Laminated plastic-worked lumber

Abstract

To increase surface hardness.SOLUTION: The laminated plastic-worked wood LPW1 is a laminated plastic-worked wood PW11 in which a surface layer plastic-worked wood PW12 and a lower layer plastic-worked wood PLW1 are laminated and bonded in a direction perpendicular to the length direction of the grain and which is plastic-worked by thermal compression and fixing in the direction perpendicular to the length direction of the grain. The lower layer plastic-worked lumber PW11 bonded to the lower side of the surface layer plastic-worked lumber PW12 forming the design surface D has knots K, and the surface layer plastic-worked lumber PW11 forming the design surface D is pressed and deformed by the knots K of the lower layer plastic-worked lumber PW12 bonded thereto, so that the design surface D side of the surface layer plastic-worked lumber PW11 is more highly compressed than the boundary side (bonding boundary BL side) with the lower layer plastic-worked lumber PW12.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to laminated plastically processed wood obtained by compressing soft wood such as cedar or cypress, and in particular to laminated plastically processed wood that can increase surface hardness. [Background technology]

[0002] In recent years, the use of wood has been promoted in an effort to realize a decarbonized society, and the appeal of wood is being rediscovered. This is because, in addition to the environmental benefits of using wood as a renewable and sustainable resource, such as helping to prevent global warming, wood is also expected to have psychological and physiological effects that bring comfort such as peace and tranquility to people due to its unique warmth and fluctuation. In particular, the use of domestic coniferous trees such as cedar and cypress reduces the energy consumed for transportation compared to imported wood, and contributes more to the development of forestry within Japan through the recycling of wood use, and to the environment by preventing disasters, etc. For this reason, there have been recent attempts to use domestic timber such as cedar and cypress not only in homes but also in public and commercial facilities, which are expected to be comfortable spaces where many people gather. By using wood in areas that many people touch and see in public and commercial facilities, not only can people feel the comfort of wood, but in public and commercial facilities that are visited by an unspecified number of people, it can also help to foster awareness of domestic forests and environmental issues through the wood that they come into contact with up close.

[0003] Considering the natural texture, warmth, and softness of wood, solid wood best captures the natural flavor of the material. However, domestic solid coniferous wood, such as cedar and cypress, is soft and therefore prone to scratches and dents. In particular, in public and commercial facilities frequented by large numbers of people, many people walk in without shoes, as in residential buildings. Therefore, wood flooring must be hard enough to withstand the concentrated loads of stiletto heels and casters. However, domestic solid coniferous wood, such as cedar and cypress, is prone to scratches and dents, detracting from the aesthetic appeal of the wood. Furthermore, even for tabletops used by large numbers of people for eating, drinking, and writing, solid coniferous wood is prone to scratches and dents. Therefore, domestic solid coniferous wood, such as cedar and cypress, cannot be used in visible areas.

[0004] Incidentally, the inventors have established a technology for compaction processing (compressive plastic processing) as disclosed in Patent Documents 1 and 2, for example, as a technology capable of improving the strength characteristics of wood (solid wood) made from domestic coniferous trees such as cedar and cypress. Patent Document 1 discloses a technology that achieves stable physical properties, little variation in quality between products, no distortion due to changes in ambient environmental conditions after commercialization, and high hardness that is resistant to scars and dents. The technology involves applying an external force to the wood, which heats and compresses the thickness of the wood to plastically process it, making the air-dry specific gravity of the heat-compressed wood at least twice the air-dry specific gravity before heat compression. The technology also discloses plastically processed wood in which the acute angle between all annual ring lines on the end grain surface of the wood and an imaginary boundary line drawn along the flat or straight grain surface on the center side of the end grain surface within a range of 2 mm or less from the flat or straight grain surface on the center side of the end grain surface is 45 degrees or less.

[0005] Patent Document 2 also discloses plastically processed wood obtained by plastically processing wood by thermal compression perpendicular to the length of the grain of the wood, in which the surface layer is a high-density plastically processed region with the highest compression rate due to thermal compression, and the back layer is a medium-density plastically processed region on the opposite side of the surface layer with a lower compression rate than the surface layer, and the back layer is a low-density plastically processed region located between the surface layer and the back layer, with the compression rate being higher than that of the inner layer, and the density distribution in the thickness direction from the surface layer side to the back layer side on the opposite side gradually changes from high density to low density from the surface side of the surface layer and the back side of the back layer on the opposite side toward the inside. This surface-compressed wood has bending points in the annual ring lines that appear on the end grain of the wood and at the boundary between the surface layer and the inner layer and at the boundary between the inner layer and the back layer, thereby making the wood mechanically stronger than the original wood and preventing splitting (cracks) even when knots are present. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-251485 [Patent Document 2] Patent No. 6450489 Summary of the Invention [Problem to be solved by the invention]

[0007] However, since Patent Documents 1 and 2 involve compressing a single piece (piece) of solid wood with a certain thickness to increase its hardness, there is a limit to how much surface hardness can be increased at a compression rate that does not cause internal cracks.

[0008] Therefore, an object of the present invention is to provide laminated plastically processed wood that can increase the surface hardness. [Means for solving the problem]

[0009] The laminated plastically processed wood of the invention of claim 1 is a laminated plastically processed wood in which multiple pieces of wood are laminated and glued together perpendicular to the length direction of the wood grain, and plastically processed by heating and compressing them perpendicular to the length direction of the wood grain and then fixing them, and the lower layer of plastically processed wood that is glued to the surface layer of plastically processed wood that forms the design surface has knots, and the surface layer of plastically processed wood is pressed and deformed by the knots of the lower layer of plastically processed wood due to the heating and compression, so that the design surface side of the surface layer of plastically processed wood is more compressed than the boundary side with the lower layer of plastically processed wood.

[0010] The above-mentioned multiple pieces of wood are stacked and bonded perpendicular to the length direction of the wood grain, and plastically processed by heat-compressing and fixing the pieces in a direction perpendicular to the length direction of the wood grain means that two or three or more pieces of wood are stacked perpendicular to the length direction of the wood grain (in the direction of the trees, standing trees), i.e., in the thickness direction of the wood, and the pieces are heat-compressed in a direction perpendicular to the length direction of the wood grain, the compression is fixed, and the wood is consolidated.This may be laminated wood that has been stacked in advance with a thermosetting adhesive applied between the pieces of wood, and the thermosetting adhesive is hardened simultaneously with the heat compression in the compaction process, thereby laminating and bonding (tightly joining) the stacked pieces of wood together; it may be laminated wood that has been stacked and bonded together in advance with multiple pieces of wood before compaction, and then heat-compressed and fixed to be compacted; or it may be laminated wood that has been stacked in advance with multiple pieces of wood without the use of an adhesive, etc., and then heat-compressed and fixed to be compacted, and then laminated and bonded together.

[0011] In addition, stacking perpendicular to the length of the grain means stacking on a surface perpendicular to the length of the grain, i.e., a surface other than the end grain surface or the edge surface, preferably on the flat grain surface or the straight grain surface, and the wood may be stacked in two or more layers (two sheets, two pieces), and may be in an odd number of layers (odd number of sheets, odd number of pieces) or an even number of layers (even number of sheets, even number of pieces). Furthermore, the term "heat compression perpendicular to the length of the grain" refers to the reduction of the area of ​​the end grain of wood by applying external force using a press or the like to wood that has been cut in a direction perpendicular to the grain direction of the annual rings (tree direction, standing tree direction).

[0012] The surface-layer plastically processed wood is the surface layer that forms the design side of the laminated plastically processed wood. It is deformed from the original wood by the pressure of the knots in the lower-layer plastically processed wood laminated and bonded underneath. The cells of the wood tissue are significantly deformed in the deformed areas due to the knots, and the design side is also significantly compressed, resulting in a higher density of the wood tissue cells, resulting in a darker color and higher compression than the boundary side with the lower-layer plastically processed wood. In other words, the compression ratio and amount are greater. The boundary between the surface-layer plastically processed wood and the lower-layer plastically processed wood laminated and bonded underneath can be distinguished from each other by a fine line or by changes in the annual ring lines on the butt end surface. The design side refers to the pressed surface that is pressed and compressed by a press platen, and is the upper (surface) side when used for flooring, tabletops, etc. Preferably, the design side is the flat grain or straight grain surface on the wood surface.

[0013] The lower layer plastically processed wood is laminated and glued under the surface layer plastically processed wood that forms the design surface, and has knots. When the laminated plastically processed wood is made by laminating, gluing, and compacting two pieces of wood (two pieces), the lower layer plastically processed wood forms the back layer of the laminated plastically processed wood, and the surface opposite to the adhesive surface (opposite surface) with the surface layer plastically processed wood forms the counter-design surface, which is opposite to the design surface side of the surface layer plastically processed wood. When the laminated plastically processed wood is made by laminating, gluing, and compacting three or more pieces of wood (three pieces), the lower layer plastically processed wood forms the inner layer of the laminated plastically processed wood, and is glued to the surface layer plastically processed wood at the upper adhesive surface (opposite surface) and to another piece of plastically processed wood at the lower adhesive surface (opposite surface). The surface plastically processed wood and the lower layer plastically processed wood may be laminated so that the grain lengths of the wood are the same, or may be laminated in a direction perpendicular to the length direction of the grain.

[0014] The above-mentioned nodes are formed when the base of a branch that has died or been artificially dropped remains on the trunk, and as the tree grows larger, it becomes buried in the cells and is incorporated (wrapped up, wrapped up) into the trunk, and is therefore part of the branch that is internal to the trunk. It does not matter whether it is a living node, which is formed when a branch is incorporated into the trunk while still alive, or a dead node, which is formed when a branch is incorporated into the trunk after dying, and the base of the branch is no longer attached to the cells.

[0015] The laminated plastically processed wood of the invention of claim 2 is a laminated plastically processed wood in which multiple pieces of wood are laminated and glued together perpendicular to the length direction of the wood grain, and plastically processed by heating and compressing them perpendicular to the length direction of the wood grain and then fixing them, wherein the surface plastically processed wood that forms the design surface has knots, and the lower layer plastically processed wood that is glued to the surface plastically processed wood is pressed and deformed by the knots of the surface plastically processed wood during the heating and compression, so that the design surface side of the surface plastically processed wood is more highly compressed than the boundary side with the lower layer plastically processed wood.

[0016] The above-mentioned multiple pieces of wood are stacked and bonded perpendicular to the length of the wood grain, and plastically processed by heat-compressing and fixing the pieces in a direction perpendicular to the length of the wood grain. This means that two or three or more pieces of wood are stacked perpendicular to the length of the wood grain (in the direction of the trees, standing trees), i.e., in the thickness direction of the wood, and then heat-compressed in a direction perpendicular to the length of the wood grain, the compression fixed, and then compacted. This may be a laminated wood that has been stacked in advance with a thermosetting adhesive applied between the pieces of wood, and then the stacked pieces are laminated and bonded together (tightly joined) by hardening the thermosetting adhesive simultaneously with the heat-compression in the compaction process; it may be a laminated wood that has been stacked and bonded together in advance with multiple pieces of wood before compaction, and then heat-compressed and fixed to be compacted; or it may be a laminated wood that has been stacked in advance with multiple pieces of wood without an adhesive, etc., and then heat-compressed and fixed to be compacted, and then laminated and bonded together.

[0017] In addition, stacking perpendicular to the length of the grain means stacking on a surface perpendicular to the length of the grain, i.e., a surface other than the end grain surface or the edge surface, preferably on the flat grain surface or the straight grain surface, and the wood may be stacked in two or more layers (two sheets, two pieces), and may be in an odd number of layers (odd number of sheets, odd number of pieces) or an even number of layers (even number of sheets, even number of pieces). Furthermore, the term "heat compression perpendicular to the length of the grain" refers to the reduction of the area of ​​the end grain of wood by applying external force using a press or the like to wood that has been cut in a direction perpendicular to the grain direction of the annual rings (tree direction, standing tree direction).

[0018] The surface plastically processed wood is the surface layer that forms the design side of the laminated plastically processed wood. It has knots, and the design side is significantly compressed and deformed, resulting in a higher density of wood tissue cells, resulting in a darker color and higher compression than the boundary side with the lower plastically processed wood. This means that the compression ratio and amount are greater. The boundary between the surface plastically processed wood and the lower plastically processed wood laminated and bonded underneath can be distinguished by a dense line or by changes in the annual ring lines on the butt end. The design side refers to the pressed surface that is pressed and compressed by a press platen, and is the upper (surface) side when used for flooring, tabletops, etc. Preferably, the design side is the cross-grain or straight-grain surface on the wood surface.

[0019] The lower layer plastically processed wood is laminated and glued under the surface layer plastically processed wood that forms the design surface, and is deformed from the original wood by the pressure of the knots in the surface layer plastically processed wood, and the cells of the wood tissue are significantly deformed in the deformed areas due to the knots. When the laminated plastically processed wood is made by laminating and bonding two pieces of wood (two pieces) and compacting it, the lower layer plastically processed wood forms the back layer of the laminated plastically processed wood, and the surface opposite to the bonding surface (facing surface) with the surface layer plastically processed wood forms the counter-design surface, which is opposite to the design surface of the surface layer plastically processed wood. When the laminated plastically processed wood is made by laminating and bonding three or more pieces of wood (three pieces) and compacting it, the lower layer plastically processed wood forms the inner layer of the laminated plastically processed wood, and is bonded to the surface layer plastically processed wood at the upper bonding surface (facing surface) and to another piece of plastically processed wood at the lower bonding surface (facing surface). The surface plastically processed wood and the lower layer plastically processed wood may be laminated so that the grain lengths of the wood are the same, or may be laminated in a direction perpendicular to the length direction of the grain.

[0020] The above-mentioned nodes are formed when the base of a branch that has died or been artificially dropped remains on the trunk, and as the tree grows larger, it becomes buried in the cells and is incorporated (wrapped up, wrapped up) into the trunk, and is therefore part of the branch that is internal to the trunk. It does not matter whether it is a living node, which is formed when a branch is incorporated into the trunk while still alive, or a dead node, which is formed when a branch is incorporated into the trunk after dying, and the base of the branch is no longer attached to the cells.

[0021] The laminated plastically processed wood of the invention of claim 3 is a laminated plastically processed wood in which multiple pieces of wood are laminated and glued together perpendicular to the length direction of the wood grain, and plastically processed by heat-compressing and fixing the pieces perpendicular to the length direction of the wood grain, and the surface layer plastically processed wood that forms the design surface and the lower layer plastically processed wood that is glued to the surface layer plastically processed wood have knots, and the surface layer plastically processed wood is pressed and deformed by the knots of the lower layer plastically processed wood due to the heat-compression, and the lower layer plastically processed wood is pressed and deformed by the knots of the surface layer plastically processed wood, so that the design surface side of the surface layer plastically processed wood is more compressed than the lower layer plastically processed wood.

[0022] The above-mentioned multiple pieces of wood are stacked and bonded perpendicular to the length of the wood grain, and plastically processed by heat-compressing and fixing the pieces in a direction perpendicular to the length of the wood grain. This means that two or three or more pieces of wood are stacked perpendicular to the length of the wood grain (in the direction of the trees, standing trees), i.e., in the thickness direction of the wood, and then heat-compressed in a direction perpendicular to the length of the wood grain, the compression fixed, and then compacted. This may be a laminated wood that has been stacked in advance with a thermosetting adhesive applied between the pieces of wood, and then the stacked pieces are laminated and bonded together (tightly joined) by hardening the thermosetting adhesive simultaneously with the heat-compression in the compaction process; it may be a laminated wood that has been stacked and bonded together in advance with multiple pieces of wood before compaction, and then heat-compressed and fixed to be compacted; or it may be a laminated wood that has been stacked in advance with multiple pieces of wood without an adhesive, etc., and then heat-compressed and fixed to be compacted, and then laminated and bonded together.

[0023] In addition, stacking perpendicular to the length of the grain means stacking on a surface perpendicular to the length of the grain, i.e., a surface other than the end grain surface or the edge surface, preferably on the flat grain surface or the straight grain surface, and the wood may be stacked in two or more layers (two sheets, two pieces), and may be in an odd number of layers (odd number of sheets, odd number of pieces) or an even number of layers (even number of sheets, even number of pieces). Furthermore, the term "heat compression perpendicular to the length of the grain" refers to the reduction of the area of ​​the end grain of wood by applying external force using a press or the like to wood that has been cut in a direction perpendicular to the grain direction of the annual rings (tree direction, standing tree direction).

[0024] The surface-layer plastically processed wood is the surface layer that forms the design side of the laminated plastically processed wood. It contains knots and is deformed from the original wood by the pressure of the knots in the lower-layer plastically processed wood laminated and bonded underneath. The cells of the wood tissue are significantly deformed in the deformed areas due to the knots. Furthermore, the design side is also significantly compressed and deformed, resulting in a higher density of the wood tissue cells, resulting in a darker color and higher compression than the boundary side with the lower-layer plastically processed wood. The boundary between the surface-layer plastically processed wood and the lower-layer plastically processed wood laminated and bonded underneath can be distinguished from each other by a fine line or by changes in the annual ring lines on the butt end surface. The design side refers to the pressed surface that is pressed and compressed by a press platen, and is the upper (surface) side when used for flooring, tabletops, etc. Preferably, the design side is the flat grain or straight grain surface on the wood surface.

[0025] The lower layer plastically processed wood is laminated and glued under the surface layer plastically processed wood that forms the design surface, and has knots. The knots are pressed into the surface plastically processed wood, deforming the original wood, and the cells of the wood tissue are significantly deformed in the deformed areas due to the knots. When the laminated plastically processed wood is made by laminating and bonding two pieces of wood (two pieces) together and compacting the wood, the lower layer plastically processed wood forms the back layer of the laminated plastically processed wood, and the surface opposite the bonding surface (facing surface) with the surface plastically processed wood forms the counter-design surface, which is opposite the design surface of the surface plastically processed wood. When the laminated plastically processed wood is made by laminating and bonding three or more pieces of wood (three pieces) together and compacting the wood, the lower layer plastically processed wood forms the inner layer of the laminated plastically processed wood, and is bonded to the surface plastically processed wood at the upper bonding surface (facing surface) and to another piece of plastically processed wood at the lower bonding surface (facing surface). The surface layer plastically processed wood and the lower layer plastically processed wood, both of which have knots, are preferably stacked so that the knots do not overlap each other in the thickness direction (stacking direction). The surface layer plastically processed wood and the lower layer plastically processed wood may be laminated so that the grain lengths of the wood are the same, or so that the grain lengths are perpendicular to each other.

[0026] The laminated plastically processed wood of the invention of claim 4 is formed by laminating and bonding the surface plastically processed wood and the lower layer plastically processed wood so that the length directions of the wood grain are aligned with each other, i.e., so that the length directions of the wood grain (the fiber directions of the annual rings) are approximately parallel to each other.

[0027] In the laminated plastically processed wood of the invention of claim 5, the design surface of the surface plastically processed wood is a plain grain or straight grain surface on the front side of the wood, and the opposite surface facing the lower layer plastically processed wood is a plain grain or straight grain surface on the back side of the wood, and the surface of the lower layer plastically processed wood facing the surface plastically processed wood is a plain grain or straight grain surface on the back side of the wood. The above-mentioned cross grain or straight grain side of the wood surface refers to the cross grain or straight grain side closer to the bark when viewed from the butt end. The side opposite the wood surface, closer to the center of the annual rings and the core material, is called the back of the wood. The above-mentioned cross grain surface refers to the surface of the wood cut in the length direction of the grain of the wood, that is, the surface of the wood cut in the tangential direction of the annual ring line, parallel to the fiber direction of the annual rings. The above-mentioned straight grain surface (sometimes called flowing straight grain or semi-straight grain) refers to a wood surface that has a wood cut or grain that is intermediate between straight grain and flat grain.

[0028] In the laminated plastically processed wood of the invention of claim 6, the Brinell hardness of the design surface side of the surface plastically processed wood is preferably 10 N / mm 2 More than 50N / mm 2 Less than or equal to 25N / mm 2 More than 50N / mm 2 More preferably, 30 N / mm 2 More than 50N / mm 2 , particularly preferably 35 N / mm 2 More than 50N / mm 2 It is within the following range: The Brinell hardness (hardness) is determined in accordance with the JIS Z 2101 wood testing method by dividing the indentation load when a 10mm diameter steel ball is pressed into the design surface of the plastically processed wood at a speed of 0.5mm per minute to a depth of approximately 0.32 (1 / π)mm by the surface area of ​​the depression remaining after the load is removed. Note that wood is a natural product, and there are differences in hardness between early wood and late wood, so here the hardness is the average of measurements taken at 10 random locations.

[0029] The laminated plastically processed wood of the invention of claim 7 has the configuration of claim 1, in which the maximum value of the acute angle between the annual ring lines appearing on the end grain surface of the lower layer plastically processed wood having the knots and the adhesive boundary line of the surface layer plastically processed wood and the lower layer plastically processed wood is greater than the maximum value of the acute angle between the annual ring lines appearing on the end grain surface of the surface layer plastically processed wood and the adhesive boundary line. The annual ring lines on the butt grain surface refer to linear portions that are densely formed when viewed from the butt grain surface, and are the wood grain that appears on the butt grain surface. In addition, the maximum value of the acute angle between the annual ring lines appearing on the butt end surface and the adhesive boundary line between the surface plastically processed wood and the lower layer plastically processed wood refers to the largest angle among the annual ring angles formed by each annual ring line appearing on the butt end surface and the adhesive boundary line between the surface plastically processed wood and the lower layer plastically processed wood.

[0030] The laminated plastically processed wood of the invention of claim 8 has the configuration of claim 7, wherein the maximum value of the acute angle formed by the annual ring lines appearing on the end grain surface of the lower layer plastically processed wood having the knots and the adhesive boundary line between the surface layer plastically processed wood and the lower layer plastically processed wood is preferably 40° or more and less than 90°, more preferably 45° or more and less than 85°, and the maximum value of the acute angle formed by the annual ring lines appearing on the end grain surface of the surface layer plastically processed wood is preferably 1° or more and 40° or less, more preferably 1° or more and 35° or less.

[0031] The laminated plastically processed wood of the invention of claim 9 has the configuration of claim 1, and the knot occupancy rate on the surface of the lower layer plastically processed wood having the knots is preferably within the range of 0.5 to 20%, more preferably 1 to 15%, and even more preferably 3 to 15%. The knot occupancy rate is calculated from the diameter of the knots on the six peripheral surfaces of the lower layer plastically processed wood when it is separated from the surface plastically processed wood (two surfaces on the butt end surface, two surfaces on the edge surface, and two surfaces on the cross-grain surface, longitudinal surface, or longitudinal grain surface), and is expressed as a percentage.

[0032] The laminated plastically processed wood of the invention of claim 10 has the configuration of claim 2, in which the maximum value of the acute angle between the annual ring lines appearing on the end grain surface of the surface plastically processed wood having the knots and the adhesive boundary line of the surface plastically processed wood and the lower layer plastically processed wood is smaller than the maximum value of the acute angle between the annual ring lines appearing on the end grain surface of the lower layer plastically processed wood and the adhesive boundary line. The annual ring lines on the butt grain surface refer to linear portions that are densely formed when viewed from the butt grain surface, and are the wood grain that appears on the butt grain surface. In addition, the maximum value of the acute angle between the annual ring lines appearing on the butt end surface and the adhesive boundary line between the surface plastically processed wood and the lower layer plastically processed wood refers to the largest angle among the annual ring angles on the acute angle between each annual ring line appearing on the butt end surface and the adhesive boundary line between the surface plastically processed wood and the lower layer plastically processed wood.

[0033] The laminated plastically processed wood of the invention of claim 11 has the configuration of claim 10, wherein the maximum value of the acute angle formed by the annual ring lines appearing on the end grain surface of the surface plastically processed wood and the adhesive boundary line of the surface plastically processed wood and the lower layer plastically processed wood is preferably 10° or more and 50° or less, more preferably 10° or more and 45° or less, and the maximum value of the acute angle formed by the annual ring lines appearing on the end grain surface of the lower layer plastically processed wood is preferably 40° or more and less than 90°, more preferably 45° or more and less than 85°.

[0034] The laminated plastically processed wood of the invention of claim 12 has the configuration of claim 2, and the knot occupancy rate on the surface of the surface plastically processed wood having the knots is preferably within the range of 0.5 to 20%, more preferably 1 to 15%, and even more preferably 3 to 15%. The knot occupancy rate is calculated from the knot diameter on the six peripheral surfaces of the surface plastically processed wood when it is separated from the lower layer plastically processed wood (two surfaces on the end grain surface, two surfaces on the edge surface, and two surfaces on the cross grain surface, longitudinal grain surface, or longitudinal grain surface), and is expressed as a percentage.

[0035] The laminated plastically processed wood of the invention of claim 13 has the configuration of claim 3, in which the maximum value of the acute angle between the annual ring lines appearing on the end grain surface of the lower layer plastically processed wood having the knot and the adhesive boundary line is greater than the maximum value of the acute angle between the annual ring lines appearing on the end grain surface of the surface layer plastically processed wood having the knot and the adhesive boundary line of the surface layer plastically processed wood and the lower layer plastically processed wood. The annual ring lines on the butt grain surface refer to linear portions that are densely formed when viewed from the butt grain surface, and are the wood grain that appears on the butt grain surface. In addition, the maximum value of the acute angle between the annual ring lines appearing on the butt end surface and the adhesive boundary line between the surface plastically processed wood and the lower layer plastically processed wood refers to the largest angle among the annual ring angles formed by each annual ring line appearing on the butt end surface and the adhesive boundary line between the surface plastically processed wood and the lower layer plastically processed wood.

[0036] The laminated plastically processed wood of the invention of claim 14 is a wood having the configuration of claim 13, wherein the maximum value of the acute angle formed by the annual ring lines visible on the end grain surface and the adhesive boundary line of the lower layer plastically processed wood having the knot is preferably 40° or more and less than 90°, more preferably 45° or more and less than 85°, and the maximum value of the acute angle formed by the annual ring lines visible on the end grain surface and the adhesive boundary line of the surface layer plastically processed wood and the lower layer plastically processed wood of the knot is preferably 10° or more and 50° or less, more preferably 10° or more and 45° or less.

[0037] The laminated plastically processed wood of the invention of claim 15 has the configuration of claim 3, and the knot occupancy rate on the wood surface of the surface plastically processed wood having knots and the lower layer plastically processed wood having knots is preferably within the range of 0.5 to 20%, more preferably 1 to 15%, and even more preferably 3 to 15%. The above knot occupancy rate is calculated by calculating the knot area from the diameter of the knots on the six surrounding surfaces of each lower layer plastically processed wood and surface layer plastically processed wood when the lower layer plastically processed wood and surface layer plastically processed wood are separated (two surfaces on the end grain surface, two surfaces on the edge surface, and two surfaces on the flat grain surface, cross grain surface, or straight grain surface), and expressing the total occupancy rate as a percentage. [Effects of the Invention]

[0038] The laminated plastically processed wood of the invention of claim 1 is made by stacking and gluing multiple pieces of wood perpendicular to the length of the grain, and plastically processing them by heating and compressing them perpendicular to the length of the grain and then fixing them, and the lower layer of plastically processed wood that is glued to the surface layer of plastically processed wood that forms the design surface has knots, and the surface layer of plastically processed wood is pressed and deformed by the knots of the lower layer of plastically processed wood due to the heating and compression, so that the design surface side of the surface layer of plastically processed wood is more compressed than the boundary side with the lower layer of plastically processed wood.

[0039] According to the laminated plastically processed wood of the invention of claim 1, multiple pieces of wood are stacked and plastically processed by thermal compression perpendicular to the length of the grain and then fixed, i.e., multiple pieces of wood are stacked in the thickness direction and plastically processed. When thermally compressed perpendicular to the length of the grain, resistance occurs at the boundaries between the stacked pieces of wood in the thickness direction, which increases the compression rate on the design surface side. Furthermore, the thermal compression causes the surface plastically processed wood to be pressed and deformed by the knots of the lower plastically processed wood, and the thickness between the hard knots closer to the design surface and the design surface is highly compressed, so the design surface side of the surface plastically processed wood is more compressed than the boundary with the lower plastically processed wood. Because the knots closer to the design surface of the lower plastically processed wood are hard, the compression rate of the thickness between the hard knots and the design surface can be increased. Therefore, the surface hardness can be increased.

[0040] The laminated plastically processed wood of the invention of claim 2 is made by stacking and gluing multiple pieces of wood perpendicular to the length of the grain, and plastically processing them by heating and compressing them perpendicular to the length of the grain and then fixing them, and the surface plastically processed wood that forms the design surface has knots, and the lower layer plastically processed wood that is adhered to the surface plastically processed wood is pressed and deformed by the knots of the surface plastically processed wood during the heating and compression, so that the design surface side of the surface plastically processed wood is more compressed than the boundary side with the lower layer plastically processed wood.

[0041] According to the laminated plastically processed wood of the invention of claim 2, multiple pieces of wood are stacked and plastically processed by thermal compression in a direction perpendicular to the length of the grain and then fixed, i.e., multiple pieces of wood are stacked and plastically processed in the thickness direction. When thermally compressed in a direction perpendicular to the length of the grain, resistance occurs at the boundaries between the stacked pieces of wood in the thickness direction, which increases the compression rate on the design surface side. Furthermore, the knots in the surface plastically processed wood press and deform the lower layer plastically processed wood during thermal compression, and the thickness between the hard knots in the surface plastically processed wood and the design surface is highly compressed without causing knot cracking. As a result, the design surface side of the surface plastically processed wood is more compressed than the boundary side with the lower layer plastically processed wood. The knots in the surface plastically processed wood are hard, and the compression rate of the thickness between the hard knots and the design surface can be increased. Therefore, the surface hardness can be increased.

[0042] The laminated plastically processed wood of the invention of claim 3 is made by stacking and gluing multiple pieces of wood perpendicular to the length of the grain, and plastically processing them by heating and compressing them perpendicular to the length of the grain and then fixing them, and the surface plastically processed wood that forms the design surface and the lower layer plastically processed wood that is adhered to the surface plastically processed wood have knots, and the surface plastically processed wood is pressed and deformed by the knots of the lower layer plastically processed wood due to the heating and compression, and the lower layer plastically processed wood is pressed and deformed by the knots of the surface plastically processed wood, so that the design surface side of the surface plastically processed wood is more compressed than the lower layer plastically processed wood.

[0043] According to the laminated plastically processed wood of the invention of claim 3, a plurality of pieces of wood are laminated and plastically processed by thermal compression in a direction perpendicular to the length direction of the wood grain and then fixed, i.e., a plurality of pieces of wood are laminated in the thickness direction and plastically processed. When thermal compression is performed in a direction perpendicular to the length direction of the wood grain, resistance occurs at the boundaries between the pieces of wood that are stacked in the thickness direction, which increases the compression rate on the design surface side. Furthermore, the lower layer plastically processed wood is pressed and deformed by the knots of the surface plastically processed wood during thermal compression, and the lower layer plastically processed wood is pressed and deformed by the knots of the surface plastically processed wood during thermal compression. The knots press and deform the surface plastically processed wood, causing no knot cracking, and the thickness between the hard knots in the surface plastically processed wood and the design surface is highly compressed. Also, the knots close to the design surface of the lower layer plastically processed wood are hard, and the thickness between these hard knots and the design surface is highly compressed. As a result, the design surface side of the surface plastically processed wood is more compressed than the boundary side with the lower layer plastically processed wood. The knots in the surface plastically processed wood are hard, and the knots close to the design surface of the lower layer plastically processed wood are also hard, and the compression rate of the thickness between these hard knots and the design surface can be increased. Therefore, the surface hardness can be increased.

[0044] According to the laminated plastically processed lumber of claim 4, the surface plastically processed lumber and the lower plastically processed lumber are laminated and bonded together with their grains aligned along the lengthwise direction. Therefore, knots in the surface plastically processed lumber and / or the lower plastically processed lumber are likely to significantly compress and deform the opposing lower plastically processed lumber and / or the surface plastically processed lumber. Therefore, in addition to the effects of claims 1 to 3, if the lower plastically processed lumber contains knots, the knots are closer to the design surface of the surface plastically processed lumber, allowing for greater compression between the hard knots and the design surface, thereby increasing the compressibility of the design surface and further enhancing surface hardness. Furthermore, if the surface plastically processed lumber contains knots, the lower plastically processed lumber is more likely to be compressed and deformed, reducing the stress on the knots and making them less likely to crack.

[0045] According to the laminated plastically processed lumber of claim 5, the design surface of the surface plastically processed lumber is the plain grain or straight grain surface on the front side of the wood, and the opposite surface facing the lower-layer plastically processed lumber is the plain grain or straight grain surface on the back side of the wood. Furthermore, since the surface surface of the lower-layer plastically processed lumber is the plain grain or straight grain surface on the back side of the wood, the design surface of the surface plastically processed lumber is easily compressed. Furthermore, since the surface plastically processed lumber and the lower-layer plastically processed lumber are laminated and bonded with the plain grain or straight grain surfaces on the back sides facing each other, the resistance at the interface between them is high when heated and compressed perpendicular to the length of the wood grain, resulting in greater compression of the design surface of the surface plastically processed lumber. Therefore, in addition to the effects of any one of claims 1 to 3, it is possible to further increase the surface hardness. In addition, the surface plastically processed wood and the lower layer plastically processed wood are laminated and glued together with the plain grain surfaces on the back side of the wood facing each other, and by balancing the anisotropy of the wood's shrinkage rate, distortion is less likely to occur even if expansion and contraction forces occur due to changes in the surrounding annular conditions, resulting in high dimensional and shape stability.

[0046] According to the laminated plastically processed wood of the invention of claim 6, the Brinell hardness of the design surface side of the surface plastically processed wood is preferably 10 N / mm 2 More than 50N / mm 2 Less than or equal to 25N / mm 2 More than 50N / mm 2 More preferably, 30 N / mm 2 More than 50N / mm 2 , particularly preferably 35 N / mm 2 More than 50N / mm 2 As a result, in addition to the effects of any one of claims 1 to 3, heel marks are unlikely to be left even when used as flooring, and even when used as a tabletop, scratches caused by writing, cutters, or collisions with heavy objects such as desk legs are unlikely to occur, making it excellent for maintaining aesthetic appearance.

[0047] According to the laminated plastically processed lumber of the invention of claim 7, the maximum value of the acute angle formed by the annual ring lines on the butt end surface of the lower layer plastically processed lumber having the knots and the adhesive boundary line between the surface layer plastically processed lumber and the lower layer plastically processed lumber is greater than the maximum value of the acute angle formed by the annual ring lines on the butt end surface of the surface layer plastically processed lumber and the adhesive boundary line in the surface layer plastically processed lumber, so that the compressive strength of the lower layer plastically processed lumber is high, and the compression of the design surface side of the surface layer plastically processed lumber can be increased. Therefore, in addition to the effect of claim 1, it is possible to improve the surface hardness.

[0048] According to the laminated plastically processed wood of claim 8, the maximum acute angle between the annual ring lines on the butt end surface of the lower layer plastically processed wood having knots and the adhesive boundary between the surface layer plastically processed wood and the lower layer plastically processed wood is preferably 40° or more and less than 90°, more preferably 45° or more and less than 85°. The maximum acute angle between the annual ring lines on the butt end surface of the surface plastically processed wood is preferably 1° or more and 40° or less, more preferably 1° or more and 35° or less. This makes the lower layer plastically processed wood less susceptible to compression, while the surface layer plastically processed wood is more susceptible to compression, thereby increasing the compressibility of the design surface of the surface layer plastically processed wood. This, in addition to the effect of claim 7, further improves surface hardness.

[0049] According to the laminated plastically processed wood of the invention of claim 9, the knot occupancy rate of the lower layer plastically processed wood having the knots on its surface is preferably within the range of 0.5 to 20%, more preferably 1 to 15%, and even more preferably 3 to 15%.Therefore, in addition to the effect described in claim 1, the compression rate on the design surface side can be increased, increasing the surface hardness, and ensuring strength that is less likely to cause cracks, fissures, etc.

[0050] According to the laminated plastically processed lumber of the invention of claim 10, the maximum value of the acute angle formed by the annual ring lines on the butt end surface of the surface plastically processed lumber having the knots and the adhesive boundary line between the surface plastically processed lumber and the lower layer plastically processed lumber is smaller than the maximum value of the acute angle formed by the annual ring lines on the butt end surface of the lower layer plastically processed lumber and the adhesive boundary line in the lower layer plastically processed lumber. Therefore, the compressive strength of the lower layer plastically processed lumber is high, and the decorative surface of the surface plastically processed lumber can be compressed more. Therefore, in addition to the effect of claim 2, it is possible to improve the surface hardness.

[0051] According to the laminated plastically processed lumber of claim 11, the maximum acute angle between the annual ring lines visible on the butt end surface of the surface plastically processed lumber having knots and the adhesive boundary between the surface plastically processed lumber and the lower plastically processed lumber is preferably 10° to 50°, more preferably 10° to 45°. The maximum acute angle between the annual ring lines visible on the butt end surface of the lower plastically processed lumber and the adhesive boundary is preferably 40° to 90°, more preferably 45° to 85°. This makes the surface plastically processed lumber relatively compressible even with knots, while the lower plastically processed lumber is less compressible. This further increases the compressibility of the design surface of the surface plastically processed lumber. This not only achieves the effects of claim 10, but also improves the surface hardness and enhances the aesthetic appearance of knots even when they are visible on the design surface.

[0052] According to the laminated plastically processed wood of the invention of claim 12, the surface plastically processed wood having knots has a knot occupancy rate on the wood surface that is preferably within the range of 0.5 to 20%, more preferably 1 to 15%, and even more preferably 3 to 15%.Therefore, in addition to the effect described in claim 2, the compression rate on the design surface side can be increased, increasing the surface hardness, and ensuring strength that is less susceptible to cracks, fractures, etc.

[0053] According to the laminated plastically processed lumber of the invention of claim 13, the maximum value of the acute angle formed between the annual ring lines appearing on the butt end surface of the lower-layer plastically processed lumber having the knot and the adhesive boundary line is greater than the maximum value of the acute angle formed between the annual ring lines appearing on the butt end surface of the surface-layer plastically processed lumber having the knot and the adhesive boundary line of the surface-layer plastically processed lumber and the lower-layer plastically processed lumber, so that the compressive strength of the lower-layer plastically processed lumber is high, thereby enabling greater compression of the design surface of the surface-layer plastically processed lumber. Therefore, in addition to the effect of claim 3, it is possible to improve surface hardness.

[0054] According to the laminated plastically processed lumber of claim 14, the maximum acute angle between the annual ring lines on the butt end surface of the lower plastically processed lumber having knots and the adhesive boundary line is preferably 40° or more and less than 90°, more preferably 45° or more and less than 85°, and the maximum acute angle between the annual ring lines on the butt end surface of the surface plastically processed lumber having knots and the adhesive boundary line of the surface plastically processed lumber and the lower plastically processed lumber is preferably 10° or more and 50° or less, more preferably 10° or more and 45° or less. Therefore, in addition to the effect of claim 13, the surface plastically processed lumber is relatively compressible even with knots, and the lower plastically processed lumber is resistant to compression, thereby further increasing the compressibility of the design surface of the surface plastically processed lumber. Therefore, in addition to the effect of claim 13, further improvement in surface hardness is possible.

[0055] According to the laminated plastically processed wood of the invention of claim 15, the knot occupancy rate on the wood surface of the surface plastically processed wood having knots and the lower layer plastically processed wood having knots is preferably within the range of 0.5 to 20%, more preferably 1 to 15%, and even more preferably 3 to 15%, so in addition to the effect described in claim 3, the compression rate on the design surface side can be increased, the surface hardness can be increased, and strength that is less likely to cause cracks, fissures, etc. can be ensured. [Brief explanation of the drawings]

[0056] [Figure 1]FIG. 1 is a cross-sectional view showing a schematic configuration of an example of a plastically processed wood manufacturing apparatus for forming laminated plastically processed wood according to each embodiment of the present invention. [Figure 2] Figure 2 is an explanatory diagram for explaining an example of a manufacturing process for laminated plastically processed wood in each embodiment of the present invention, where (a) is an explanatory diagram of the supply of wood before laminated processing to be plastically processed, (b) is an explanatory diagram of the start state of heating and compression, (c) is an explanatory diagram of the heating and compression state in a sealed state, (d) is an explanatory diagram of steam pressure control processing in a sealed state, (e) is an explanatory diagram of the cooling state in a sealed state, and (f) is an explanatory diagram of the removal of laminated plastically processed wood. [Figure 3] Figure 3 is an explanatory diagram showing the relationship between laminated plastically processed wood in embodiment 1 of the present invention before and after plastic processing, where (a) is an oblique view of the unprocessed wood before plastic processing, and (b) is an oblique view of the laminated plastically processed wood after plastic processing. [Figure 4] Figure 4(a) is a partially enlarged explanatory diagram showing the relationship between the laminated plastically processed wood according to embodiment 1 of the present invention before and after plastic processing, and Figure 4(b) is an explanatory diagram of the laminated plastically processed wood according to embodiment 1 of the present invention viewed from the butt end side. [Figure 5] Figure 5(a) is a partially enlarged explanatory diagram showing the relationship between laminated plastically processed wood according to embodiment 2 of the present invention before and after plastic processing, and Figure 5(b) is an explanatory diagram of laminated plastically processed wood according to embodiment 2 of the present invention viewed from the butt end side. [Figure 6] Figure 6(a) is a partially enlarged explanatory diagram showing the relationship between laminated plastically processed wood according to embodiment 3 of the present invention before and after plastic processing, and Figure 6(b) is an explanatory diagram of laminated plastically processed wood according to embodiment 3 of the present invention viewed from the butt end side. [Figure 7] Figure 7(a) is a partially enlarged explanatory diagram showing the relationship between laminated plastically processed wood according to embodiment 4 of the present invention before and after plastic processing, and Figure 7(b) is an explanatory diagram of laminated plastically processed wood according to embodiment 4 of the present invention viewed from the butt end side. [Figure 8]Figure 8(a) is a partially enlarged explanatory diagram showing the relationship between laminated plastically processed wood according to embodiment 5 of the present invention before and after plastic processing, and Figure 8(b) is an explanatory diagram of laminated plastically processed wood according to embodiment 5 of the present invention viewed from the butt end side. [Figure 9] Figure 9(a) is a partially enlarged explanatory diagram showing the relationship between laminated plastically processed wood according to embodiment 6 of the present invention before and after plastic processing, and Figure 9(b) is an explanatory diagram of laminated plastically processed wood according to embodiment 6 of the present invention viewed from the butt end side. DETAILED DESCRIPTION OF THE INVENTION

[0057] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each embodiment, the same symbols and the same reference numerals refer to the same or corresponding functional parts, and the same symbols and the same reference numerals between the embodiments represent functional parts common to those embodiments, so duplicate detailed explanations will be omitted here.

[0058] [Common matters among all embodiments] First, common features of the embodiments will be described mainly with reference to FIGS. The raw material for the laminated plastically processed lumber LPW1, LPW2, LPW3, LPW4, LPW5, and LPW6 (hereinafter, when the laminated plastically processed lumber LPW1, LPW2, LPW3, LPW4, LPW5, and LPW6 are not particularly distinguished, they will simply be referred to as "laminated plastically processed lumber LPW") in each embodiment is raw material, raw lumber NW11, 12, 13,...,n (hereinafter, when the raw lumber NW11, NW12, NW13,..., NWn are not particularly distinguished, they will simply be referred to as "raw lumber NW"), which is pre-sawn to a predetermined dimension (thickness, width, length), i.e., felled logs or logs cut into lumber or boards and adjusted to the predetermined dimensions. Thinned lumber, damaged wood that has fallen or suffered core cracks due to natural disasters such as wind damage, flood damage, snow damage, forest fires, frost damage, and insect damage and is therefore unusable as a log, scrap wood, etc. may also be used. The thickness, width and length of the raw wood NW are appropriately set depending on the use and purpose of the laminated plastically processed wood LPW obtained by stacking and compacting the raw wood NW.

[0059] As the unprocessed wood NW, preferably, sawn lumber cut as flat grain lumber or straight grain lumber is used. Note that cross-grain lumber is wood that has been sawn tangent to the growth rings of the log, i.e., cross-grained, while straight-grain lumber is wood that is sawn in an intermediate manner between straight-grain lumber, which is sawn perpendicular to the growth rings of the log, and cross-grain lumber, which is sawn in the tangent direction of the growth rings of the log. Cross-grain lumber typically has end grain surfaces (two sides) cut perpendicular to the grain direction of the growth rings, cross-grain surfaces (two sides: the top and bottom of the wood), and edge surfaces (two sides: straight-grained surfaces). Straight-grain lumber typically has end grain surfaces (two sides) cut perpendicular to the grain direction of the wood, cross-grained surfaces (two sides: the top and bottom of the wood), which are intermediate between cross-grain and straight-grain, and edge surfaces (two sides: straight-grained surfaces). In straight-grain lumber, the growth rings appear in a parallel pattern, while in cross-grain lumber, the growth rings appear in a wavy or chevron pattern. Furthermore, the cross grain has a top and a bottom. The top is the side of the cross grain lumber that is closer to the bark, and the bottom is the side that is closer to the heartwood (core). Therefore, the cross grain is the surface of the wood cut in the lengthwise direction of the grain, i.e., parallel to the grain direction of the annual rings and tangential to the ring lines. The straight grain is the surface of the wood cut in the direction parallel to the grain direction of the annual rings and roughly radially (approximately radially) from the ring lines. Furthermore, the straight grain (also called the flowing straight grain or semi-straight grain) is a wood cut or grain that is intermediate between the straight grain and the cross grain. The end grain is the surface of the wood cut in a direction that intersects with the grain direction of the annual rings, i.e., perpendicular or diagonal to the lengthwise direction of the wood grain. The illustrations will be explained using the examples of cross grain and straight grain lumber.

[0060] The wood species is not particularly limited, and either coniferous or broad-leaved trees may be used. Examples include cedar, cypress, pine (larch, todomatsu, sakhalin, red pine, etc.), sawara, walnut, yellow poplar, Italian poplar, fir, hemlock, spruce, yew, asunaro, paulownia, hiba, birch, castanea, quince, falcata, gmelina, chinaberry, and tulip tree. Cedar and cypress are particularly widely distributed in Japan, and because they can be easily obtained in large quantities as thinned wood, they can contribute to environmental conservation.

[0061] Before undergoing a predetermined plastic processing (compaction) using a plastically processed wood manufacturing apparatus 100 shown in Figures 1 and 2, the raw wood NW is dried to a moisture content below the fiber saturation point. Drying to a moisture content below the fiber saturation point, preferably below the air-dry moisture content, provides strength and allows for sufficient chemical change during subsequent heating and compression. The moisture content of wood is the ratio of the moisture weight to the weight of wood without moisture (total dry weight, dry base), and can be measured using a measuring device such as a high-frequency moisture meter. Generally, moisture evaporates from the surface of wood, so the moisture content of wood decreases closer to the surface. However, the moisture content here refers to the value measured as the moisture content of the entire wood.

[0062] The raw wood NW can be dried to a predetermined moisture content using a known drying device, such as an artificial dryer (steam dryer, weak vacuum dryer, etc.) that uses high-temperature steam as a heat source and has a built-in refrigerator. This method is not limited to artificial drying, and natural drying (natural drying) can also be used. The overall moisture content of the raw wood NW is measured in advance, and the drying conditions in the drying device, such as the artificial dryer, are set based on the moisture content measured at that time, the wood species of the raw wood NW, its thickness, etc., so that the predetermined moisture content is achieved after drying. For example, in the case of cedar or cypress, the drying temperature is set to approximately 40 to 100°C, the wet-dry-bulb temperature difference is set to approximately 1 to 30°C, and the drying period is set to approximately 3 to 10 days. Typically, the drying temperature is gradually increased and the humidity is gradually decreased during the drying period. Although it is possible to increase the strength of the raw wood NW by reducing its moisture content, if the moisture content of the raw wood NW is lowered more than necessary, the strength of the raw wood NW will be reduced due to shrinkage, and cracks will occur during the drying process. Therefore, for example, in the case of cedar or cypress wood, it is preferable to dry the raw wood NW so that the overall moisture content is within the range of 5% to 15%. A moisture content of 8% to 10% is more preferable.

[0063] Here, in each embodiment, the laminated plastically processed wood LPW is made by stacking two or more pieces of pre-processed wood NW11, 12, 13, ..., n to form laminated pre-processed wood LNW1, LNW2, LNW3, LNW4, LNW5, LNW6 (hereinafter, when no particular distinction is made between the laminated plastically processed wood LNW1, LNW2, LNW3, LNW4, LNW5, LNW6, they will simply be referred to as ``pre-processed laminated wood LNW''), which is subjected to heat compression and compression fixation to give it the thickness of a single piece of laminated plastically processed wood LPW, and the thickness of each piece (piece) of pre-processed wood NW sawn from the raw material can be made thinner. That is, to produce laminated plastically processed wood LPW for use as tabletops, shelves, floorboards, etc. for desks such as school desks, study desks, office work desks, and home dining tables, two or more thin sheets of pre-processed wood NW are stacked and heated and compressed, and the thin pre-processed wood NW, for example, having a thickness in the range of 10 mm to 30 mm, preferably 12 to 25 mm, is dried.

[0064] Therefore, drying each piece of raw wood NW to a predetermined moisture content requires less drying time than drying a single piece of solid wood to a predetermined thickness, making it less likely to develop surface drying cracks. Furthermore, it is possible to bring the moisture content of the wood's interior closer to that of the surface. That is, a single piece of laminated plastically processed wood LPW is made by laminating and gluing together multiple pieces of raw wood NW and then compacting them to a single thickness. Because each piece of raw wood NW is thin, the drying time in the drying process before compaction can be shortened, reducing the drying load. Therefore, even if knots are used as raw material raw wood NW, knot cracks and knot loss due to drying are less likely to occur, improving yield. Furthermore, because the moisture content of the thin raw wood NW can be reduced between the interior and surface, localized compression deformation and stress are less likely to occur during subsequent heat compression, making it less likely for the wood to develop internal cracks due to heat compression. Therefore, even if a knot K exists, it is difficult for a crack or other breakage to occur there. Here, we have explained that wood cut from logs or raw timber is sawn to a specified size and then dried, but when implementing this invention, wood cut from raw timber or logs may also be dried to a specified moisture content and then sawn to a specified size.

[0065] The laminated plastically processed wood LPW in each embodiment is manufactured by heating, compressing, and compressing and fixing laminated pre-processed wood LNW, which is made by stacking multiple sheets of pre-processed wood NW that have been dried to a predetermined moisture content using an adhesive. The laminated pre-processed wood LNW is formed by applying adhesive to the stacking surfaces (facing surfaces of the pre-processed wood NW) of multiple sheets of pre-processed wood NW dried to a predetermined moisture content, and then stacking the pre-processed wood NW dried to a predetermined moisture content perpendicular to the length direction of the wood grain. In other words, the laminated pre-processed wood LNW is formed by stacking multiple sheets of pre-processed wood NW in the thickness direction of the pre-processed wood NW with adhesive interposed between the pre-processed wood NW.

[0066] Here, in the laminated pre-processed lumber LNW of each embodiment, lumber having one or more knots K is used at least for the surface layer pre-processed lumber NW11 of the surface layer (upper layer) and / or the lower layer pre-processed lumber NW12 of the lower layer laminated thereunder. In this case, if a knot K exists in the surface layer pre-processed lumber NW11, the knot-free portion of the lower layer pre-processed lumber NW12 is overlapped with the knot K present in the surface layer pre-processed lumber NW11, and the surface layer pre-processed lumber NW11 and the lower layer pre-processed lumber NW12 are laminated. Also, if a knot K exists in the lower layer pre-processed lumber NW12, the knot-free portion of the surface layer pre-processed lumber NW11 is overlapped with the knot K present in the lower layer pre-processed lumber NW12, and the surface layer pre-processed lumber NW11 and the lower layer pre-processed lumber NW12 are laminated. In other words, the knots K are prevented from overlapping each other in the thickness direction.

[0067] As a result, if knots K are present in the pre-surface-layer-processing wooden piece NW11, the knots K in the pre-surface-layer-processing wooden piece NW11 will press and deform the knot-free areas of the lower-layer-processing wooden piece NW12 during the subsequent heated compression process, and the force applied to the knots K in the pre-surface-layer-processing wooden piece NW11 will be absorbed by the knot-free areas of the lower-layer-processing wooden piece NW12, making it less likely for cracks or fissures to occur even if knots K are present. Furthermore, if knots K are present in the pre-surface-layer-processing wooden piece NW11, the thickness between the hard knots K and the design surface D will be strongly compressed.

[0068] Furthermore, if knots K exist in the lower layer pre-processing wood NW12 that is placed under the surface layer pre-processing wood NW11, the knots K of the lower layer pre-processing wood NW12 will press and deform the knot-free areas of the surface layer pre-processing wood NW11 during the subsequent heated compression process, and the force applied to the knots K of the lower layer pre-processing wood NW12 will be absorbed by the knot-free areas of the surface layer pre-processing wood NW11, making it less likely for cracks or fissures to occur even if knots K exist. The knots K of the lower layer pre-processing wood NW12 will then approach the design surface D, and the thickness between the hard knots K and the design surface D will be strongly compressed.

[0069] The adhesive applied to the opposing surfaces of the unprocessed wooden pieces NW to be stacked before heat compression, i.e., the adhesive for bonding the wooden pieces together, may be a thermosetting resin adhesive capable of bonding the wooden pieces together under the heat compression conditions of the plastic processing (heat compression and compression fixing) using a hot press (a pair of press plates 10A, 10B) described below, a thermoplastic resin adhesive, or a two-part mixed reactive curing adhesive. Preferably, a thermosetting adhesive that hardens during the heat compression of the plastic processing described below to bond the wooden pieces together can be used to obtain high adhesive strength. Examples of thermosetting resin adhesives that can be used include aqueous vinyl urethane adhesives (aqueous polymer isocyanate adhesives), urethane resin adhesives, vinyl acetate resin adhesives, urea resin adhesives, epoxy resin adhesives, phenolic resin adhesives, and synthetic rubber adhesives.

[0070] The amount of adhesive to be applied at this time is determined depending on the type of adhesive, etc. For example, in the case of a water-based vinyl urethane adhesive, the amount to be applied is 200 g / m 2 The above is preferable. Aqueous vinyl urethane adhesives can easily penetrate even wood made from conifers, providing sufficient adhesive strength to firmly bond wood pieces together during the plastic processing described below. In particular, they can penetrate into knots K, alleviating the compressive stress on the knots K during the subsequent heat compression in the plastic processing and protecting the knots K, making them effective in preventing knot K cracking during the subsequent heat compression. The adhesive application method is not particularly limited, and the adhesive may be applied to one side of the pre-processed wood NW, or, if an odd number of sheets are stacked, applying the adhesive to both sides of the pre-processed wood NW that is placed on the even-numbered sheets allows the adhesive to be applied for joining with little effort and man-hours.

[0071] Furthermore, in a laminated unprocessed wood LNW formed by stacking multiple unprocessed wood pieces NW with an adhesive therebetween, the unprocessed wood piece NW11 located in the surface layer forming the design surface D may be made of wood that has been dried and then moistened. That is, in implementing the present invention, after drying to a predetermined moisture content as described above, moisture may be added to the unprocessed wood piece NW11 located in the surface layer, i.e., humidified, in order to facilitate heat compression of the surface layer (upper layer) that will be on the design surface D side when the unprocessed wood pieces NW are stacked. For example, moisture can be added to the unprocessed wood piece NW11 located in the surface layer by immersing the entire unprocessed wood piece NW after drying in water for a predetermined time (e.g., about 5 minutes). The means for moisturizing the dried unprocessed wood piece NW11 located in the surface layer is not limited to immersing the wood in water. Water may also be sprayed or sprayed onto the design surface D with a spray or by applying water with a brush.

[0072] Laminated plastically processed wood LPW is produced by subjecting laminated pre-processed wood LNW, which is made by stacking two or more sheets of pre-processed wood NW with an adhesive therebetween, to plastic processing, including heat compression and compression fixation. If a thermosetting adhesive is used as the adhesive applied between the pre-processed wood NW, the adhesive hardens due to the heat applied during the plastic processing, including heat compression and compression fixation, and the wood pieces are bonded together.

[0073] A procedure for producing laminated plastically processed wood LPW by subjecting pre-laminated wood LNW to plastic processing, including heat compression and compression fixing, will be described in detail below with reference to FIGS. 1 and 2, the plastically processed wood manufacturing apparatus 100 for producing laminated plastically processed wood LPW is mainly composed of a press platen 10 which forms an internal space IS by a two-part structure consisting of an upper press platen 10A and a lower press platen 10B, a sealing member 11 which is arranged on the peripheral portion 10a of the upper press platen 10A opposite the peripheral portion 10b of the lower press platen 10B and keeps the internal space IS sealed within a predetermined range of up and down movement of the upper press platen 10A, a pipe 12 which is connected to the internal space IS from the upper side of the upper press platen 10A and has a pipe opening 12a for supplying steam into the internal space IS, a valve V4 upstream of the pipe 12, a pipe 13 which is connected to the internal space IS from the side of the lower press platen 10B and has a pipe opening 13a for discharging water vapor from the internal space IS, a pressure gauge P2 which detects the steam pressure in the pipe 13, a valve V5 downstream of the pipe 12, and a drain pipe 14 connected to the valve V5.

[0074] The press platen 10 is a flat mold of a size that can press the entire front and back surfaces of the wood LNW before lamination processing. The material of the mold is not particularly important, but to prevent the wood from turning black due to iron ion contamination, for example, the mold may be made of steel such as stainless steel or aluminum, or the mold surface may be plated. The material of the sealing member 11 for sealing the internal space IS is not particularly limited, but silicone rubber, silicone resin, or the like, which has excellent heat resistance and water resistance, is usually used.

[0075] Pipes ST2 and ST3 branched from steam supply pipe ST1 and steam discharge pipes ET1 and ET2 are connected to these pipes 15 and 16. Valves V1, V2, and V3 and a pressure gauge P1 for detecting the steam pressure in pipe ST1 are provided midway along steam supply pipes ST1, ST2, and ST3, and steam discharge pipes ET1 and ET2 are connected to drain pipe 14 via valve V6.

[0076] Furthermore, pipes ST12 and ST13 branch off from a cooling water supply pipe ST11, which cools to a desired temperature by passing low-temperature cooling water in place of high-temperature steam through pipe paths 15 and 16 formed in the upper press platen 10A and the lower press platen 10B, and are connected to the pipes ST2 and ST3, respectively. Valves V11, V12, and V13 are provided midway along the cooling water supply pipes ST11, ST12, and ST13. 1 and 2, the boiler device that supplies high-temperature steam to the piping ST1, the cooling water supply device that supplies cooling water to the piping ST11, and the press lifting device including a hydraulic mechanism for raising / lowering and pressurizing the upper press platen 10A relative to the lower press platen 10B on the fixed side of the press platen 10 are omitted.

[0077] When plastically processing (densifying) pre-laminated wood LNW using the plastically processed wood manufacturing apparatus 100 having such a configuration, first, as shown in Figure 2(a), the movable upper press plate 10B is raised relative to the fixed lower press plate 10B that constitutes the press plate 10, and the pre-laminated wood LNW is placed on the fixed lower press plate 10B. At this time, the side of the laminated plastically processed lumber LPW that will be the design surface D is placed facing the upper press platen 10A, and the side that will be the anti-design surface is placed facing the lower press platen 10B. That is, the surface unprocessed lumber NW11 of the laminated unprocessed lumber LNW is placed facing the upper press platen 10A, and the lower layer unprocessed lumber NW12 is placed facing the lower press platen 10B.

[0078] In this way, the pre-laminated wood LNW is placed between the upper press platen 10A and the lower press platen 10 so that the press surfaces of the upper press platen 10A and the lower press platen 10 are perpendicular to the stacking direction of the pre-laminated wood LNW, and the pre-laminated wood LNW is pressed perpendicular to the longitudinal direction of the grain of the pre-laminated wood LNW by the press platen 10, which is divided into two parts, the upper press platen 10A and the lower press platen 10B.

[0079] Specifically, as shown in Figure 2(b), the pre-laminated wood LNW is placed on the fixed lower press platen 10B of the press platen 10, with the front and back surfaces of the pre-laminated wood LNW in the lamination direction facing the upper press platen 10A and lower press platen 10B.First, the upper press platen 10A is lowered at a predetermined pressure (e.g., 0.05 to 0.3 MPa) to bring the upper surface of the pre-laminated wood LNW, i.e., the surface of the pre-surface-processed wood NW11 of the pre-laminated wood LNW (preferably the plain grain or straight grain surface on the front side of the wood), into contact for a predetermined time (e.g., 10 to 120 seconds). At this time, high-temperature steam at a predetermined temperature (e.g., 110 to 210°C, heating treatment time 10 to 25 minutes) is passed through the piping 15 of the upper press platen 10A and the piping 16 of the lower press platen 10B, thereby heating the upper press platen 10A and the lower press platen 10B to a predetermined temperature (e.g., 110 to 210°C).

[0080] The compression pressure of the upper press platen 10A against the fixed lower press platen 10B is set to a predetermined pressure (for example, 2 to 5 MPa, 20 to 50 kg / cm 2 ), and the pre-laminar wood LNW is heated and compressed by the upper press platen 10A and the lower press platen 10B (for example, a processing time of 0.5 to 3 minutes and a compression speed of 15 to 100 mm / min). As the upper press platen 10A descends, the pre-laminar wood LNW is heated and compressed by the upper press platen 10A and the lower press platen 10B, and when the peripheral edge 10a of the upper press platen 10A abuts against the peripheral edge 10b of the lower press platen 10B, as shown in FIG. 2(c), the internal space IS formed by the upper press platen 10A and the lower press platen 10B is sealed by the seal member 11 disposed on the peripheral edge 10a of the upper press platen 10A.

[0081] The vertical dimension of the internal space IS formed by the upper press platen 10A and the lower press platen 10B of the press platen 10 when the internal space IS is sealed via the sealing member 11 is set to the finished dimension in the thickness direction when the press platen 10 produces laminated plastically processed lumber LPW with a predetermined compression ratio relative to the thickness of the pre-lamination lumber LNW. Therefore, the compression ratio throughout the thickness of the pre-lamination lumber LNW, i.e., the change in thickness (compression amount) due to compression of the pre-lamination lumber LNW, is determined by the contact of the peripheral edge 10a of the upper press platen 10A with the peripheral edge 10b of the lower press platen 10B. The pressure, heating temperature, heating time, compression speed, etc. of the press platen 10 at this time are optimally set in advance through experiments, etc., using parameters such as the wood species and the moisture content of the dried lumber as parameters. If the peripheral portion 10a of the upper press platen 10A and the peripheral portion 10b of the lower press platen 10B are constructed with, for example, a jig, formwork, gauge, etc. for regulating thickness, the height of the peripheral portion 10a of the upper press platen 10A and the peripheral portion 10b of the lower press platen 10B can be adjusted according to the desired finished thickness of the laminated plastically processed wood LPW.

[0082] It is also possible to place a restraining device (spacer) (not shown) on the side of the pre-laminated lumber LNW during pressing to restrict elongation in the width direction (lateral or horizontal direction), for example. Restricting the elongation of the pre-laminated lumber LNW in the width direction perpendicular to the length direction of the grain (i.e., perpendicular to the compression direction) using a restraining device makes it easier to fix specific dimensions and specific gravity, preventing product-to-product variation and ensuring high quality. Such restriction can result in higher density at the widthwise edges of the lumber. Conversely, without restriction, the density of the widthwise edges of the lumber can be lower than that of the center. Depending on the difference in density across the width of the lumber, it is also possible to mill the surface of the widthwise edges of the lumber after compaction. In addition, the plastically processed wood manufacturing apparatus 100 can produce a large amount of laminated plastically processed wood LPW at one time by arranging multiple pre-laminated wood LNWs in the length direction of the grain of the pre-laminated wood LNW or in the width direction perpendicular to the length direction of the grain and compacting them together.

[0083] In this way, when the lower press platen 10B is fixed in place on the press platen 10 heated to a predetermined temperature and the upper press platen 10A is moved to contact the upper surface of the pre-laminated wood LNW with a predetermined pressure and lowered at a predetermined compression speed, the strength of the pre-laminated wood LNW decreases due to changes in the chemical properties of the wood components (hydrolysis of amorphous components such as hemicellulose and lignin, and a decrease in softening point) from the front and back layers to the inside, causing the cells to compress and deform, reducing the void space within the cells.

[0084] Next, with the internal space IS sealed as shown in Figure 2(d), the compression pressure of the upper press platen 10A and the lower press platen 10B is maintained, and the upper press platen 10A and the lower press platen 10B are kept at a predetermined temperature (e.g., 110 to 210°C), and the thermal compression treatment of the wood is fixed, i.e., the wood is fixed. For example, a predetermined steam pressure is supplied to the sealed internal space IS via pipe 12 and pipe port 12a (Fig. 1) connected to valve V4. The compression pressure and heating temperature of upper press platen 10A and lower press platen 10B are maintained at the same predetermined pressure and temperature as those used during thermal compression. The sealed internal space IS is then maintained at the predetermined temperature and steam pressure for a predetermined time (e.g., 20 to 90 minutes). High-temperature steam at a predetermined temperature (e.g., 110 to 210°C) is introduced into the internal space IS to adjust the sealed internal space IS to the predetermined temperature and steam pressure. The high-temperature, high-pressure steam induces sufficient chemical changes in the thermally compressed wood placed within the sealed internal space IS, resulting in uniform properties. This allows the production of laminated plastically processed lumber (LPW) that will not return to its original state when the subsequent cooling and compression is released.

[0085] During this process, high-temperature, high-pressure steam flows freely between the periphery and interior of the heated and compressed wood. Depending on the moisture content of the heated and compressed wood, the internal space IS, sealed by the upper press platen 10A and the lower press platen 10B, may be adjusted to a predetermined steam pressure. For example, excess moisture in the internal space IS based on the moisture content of the wood on both sides may be removed, and the internal space IS may be adjusted to a predetermined steam pressure. That is, while the heat-compressed wood is being fixed in the sealed internal space IS, the steam pressure may be detected by the pressure gauge P2 as a steam pressure control process. The valve V5 may be opened and closed as appropriate to allow high-temperature, high-pressure steam to be discharged from the internal space IS to the drain pipe 14 through the pipe opening 13a and pipe 13. Furthermore, a predetermined steam pressure may be supplied to the sealed internal space IS as needed.

[0086] 2(d), just before the transition from heating compression to cooling compression using the upper press platen 10A and the lower press platen 10B occurs, valve V5 is opened as a steam pressure control process, and high-temperature, high-pressure steam is discharged from the compression space IS through pipe port 13a and pipe 13 to the drain pipe 14 side. This further promotes the fixation of the wood. At this time, the supply of steam to maintain the upper press platen 10A and the lower press platen 10B at a specific temperature is also temporarily stopped.

[0087] 2(e), room temperature cooling water is passed through the piping 15 of the upper press platen 10A and the piping 16 of the lower press platen 10B to cool the upper press platen 10A and the lower press platen 10B to about room temperature, and this is maintained for a predetermined time (e.g., 20 to 90 minutes). At this time, the compression pressure of the upper press platen 10A against the fixed lower press platen 10B is maintained at the same predetermined pressure (e.g., 2 to 5 MPa) as that used during thermal compression, while the upper press platen 10A and the lower press platen 10B are cooled. Then, as shown in Figure 2(f), the upper press platen 10A is raised relative to the fixed lower press platen 10B, and the laminated plastically processed wood LPW that has completed plastic processing (compacting processing) through heating, compression, and fixation is removed from the internal space IS, completing the entire processing process.

[0088] The laminated plastically processed lumber LPW removed from the internal space IS has been compacted through a series of processing steps: heat compression, steam pressure, and cooling. Furthermore, if the adhesive applied between the pieces of wood NW is thermosetting, the adhesive hardens through these processing steps, resulting in the plastically processed lumber PW11, PW12, PW13, ..., PWn being laminated and bonded together.

[0089] After this, if necessary, one or both surfaces of the laminated plastically processed lumber LPW are machined to ensure the flatness of the product. The sides may also be machined. Usually, the finished product is completed after this machining process. Furthermore, if necessary, the surface of the laminated plastically processed lumber LPW may be coated with a resin or other material to protect it from moisture and dirt.

[0090] In this way, laminated plastically processed lumber LPW is obtained in which two or more pieces of plastically processed lumber PW11, PW12, PW13, ..., PWn that have been heated and compressed in a direction perpendicular to the length direction of the wood grain and plastically processed (densified) are laminated and bonded in a direction perpendicular to the length direction of the wood grain. In other words, the laminated plastically processed lumber LPW is obtained in which two or more pieces of unprocessed lumber NW11, 12, 13, ..., n have been heated and compressed in a direction perpendicular to the length direction of the wood grain and plastically processed (densified) to form plastically processed lumber PW11, PW12, PW13, ..., PWn that have been laminated and bonded together.

[0091] Although the example described here uses high-temperature steam to heat the upper press platen 10A and the lower press platen 10B of the press platen 10, when practicing the present invention, the heating medium for the press platen 10 is not limited to high-temperature steam, and oil or the like may also be used, and the wood can also be heated by a heating means such as high-frequency heating, microwave heating, or a heater. In particular, when high-frequency heating the wood, a method of heating the wood from the center using a high-frequency wave with a frequency slightly lower than that of microwaves is preferable to dielectric heating using microwaves.

[0092] [Embodiment 1] Next, the laminated plastically processed wooden piece LPW1 according to the first embodiment of the present invention will be described with reference to FIGS. The laminated plastically processed lumber LPW1 of this embodiment 1 is made by stacking two pieces (two pieces) of unprocessed lumber NW11 and unprocessed lumber NW12 perpendicular to the length direction of their grain using an adhesive, and then plastically processing (compacting) them by performing a heat compression and compression fixation process perpendicular to the length direction of the grain. In this first embodiment, the two pieces of unprocessed lumber NW11 and unprocessed lumber NW12 are both made of cedar or cypress. That is, the surface layer plastically processed lumber PW11 and the lower layer plastically processed lumber PW12 that make up the laminated plastically processed lumber LPW1 are made of cedar or cypress.

[0093] In detail, the laminated plastically processed timber LPW1 of this embodiment 1 uses knot-free pre-surface-layer timber NW11 on the surface layer facing the design surface D, and layers a lower layer pre-processed timber NW12 (lower layer pre-processed timber NW12) with one or more knots K underneath the knot-free pre-surface-layer timber NW11; in other words, the knot-free pre-surface-layer timber NW11 and the lower layer pre-processed timber NW12 with knots K are stacked in the thickness direction, which is perpendicular to the length direction of the wood grain, and then compacted by performing a heat compression treatment and a compression fixation treatment perpendicular to the length direction of the wood grain, and the laminated plastically processed timber LPW1 consists of knot-free surface-layer timber PW11 and knot-free lower layer timber PW12 stacked and bonded together.

[0094] In the laminated plastically processed timber LPW1 of this first embodiment, wood without knots K is used for the surface layer pre-processing timber NW11 that serves as the raw material, and wood with knots K is used for the lower layer pre-processing timber NW12, but preferably, flat grain timber or straight grain timber is used for the surface layer pre-processing timber NW11 that does not have knots K and the lower layer pre-processing timber NW12 that has knots K. In other words, the surface layer plastically processed timber PW11 and the lower layer plastically processed timber PW12 that constitute the laminated plastically processed timber LPW1 are preferably flat grain timber or straight grain timber.

[0095] More preferably, as shown in Figures 3 and 4, the pre-surface-processed lumber NW11 without knots K has the flat grain or straight grain side of its front surface facing the design surface D, and the flat grain or straight grain side of the back surface of the wood on the opposite side facing the pre-underlayer-processed lumber NW12 with knots K, and the pre-surface-processed lumber NW11 without knots K and the pre-underlayer-processed lumber NW12 with knots K are stacked in their thickness direction, with the flat grain or straight grain side of the back surface of the wood facing the pre-surface-processed lumber NW11 and the flat grain or straight grain side of the front surface of the wood on the opposite side facing the design surface D.

[0096] Furthermore, in this embodiment 1, the surface layer unprocessed timber NW11 without knots K and the lower layer unprocessed timber NW12 with knots K are stacked perpendicular to the length direction of the wood grain with the length directions of the wood grain aligned. That is, the laminated plastically processed timber LPW1 of this embodiment 1 is formed by stacking and bonding the surface layer plastically processed timber PW11 and the lower layer plastically processed timber PW12 that constitute it with the length directions of the wood grain aligned.

[0097] In this embodiment 1, the surface layer pre-processed wood NW11 without knots K is used as the surface layer (upper layer), and the lower layer pre-processed wood NW12 with knots K is stacked underneath the surface layer pre-processed wood NW11 to form the lower layer (back layer), and adhesive is applied between them and stacked to form laminated pre-processed wood LNW1.The laminated pre-processed wood LNW1 consisting of two pieces of pre-processed wood NW11, NW12 is heated and compressed in the thickness direction, i.e., perpendicular to the length direction of the grain of the pre-processed wood NW11, NW12, and then compaction processing (plastic processing) is performed to fix the compression, thereby forming laminated plastically processed wood LPW1 consisting of surface layer plastically processed wood PW11 and lower layer plastically processed wood PW12 stacked and bonded together.

[0098] Here, when knot-free unprocessed lumber NW11 is stacked as the surface layer (top layer) and knot-free unprocessed lumber NW12 as the bottom layer (bottom layer), and these are heated and compressed perpendicular to the length direction of the wood grain, resistance (compressive stress) occurs at the boundary between the unprocessed lumber NW11 and the bottom layer NW12 due to the different wood structures (discontinuous wood structure) between them, and this allows for significant compression of the design surface D side of the unprocessed lumber NW11 closer to the movable press platen 10A. Furthermore, because the knots K in the bottom layer unprocessed lumber NW12 are hard, the hard knots K press and deform the softer parts of the unprocessed lumber NW11 without knots, bringing the knots K closer to the design surface D side. Furthermore, because the knots K are hard, the thickness between the hard knots K and the design surface D can be significantly compressed. This increases the compression rate on the design surface D side, thereby increasing the surface hardness.

[0099] In particular, in the first embodiment, the knot-free pre-surface-layer lumber NW11 and the knot-free lower-layer lumber NW12 are laminated perpendicular to the grain direction with their grain lengths aligned, and the knots of the lower-layer pre-processing lumber NW12 are likely to press and deform the knot-free soft portions of the pre-surface-layer lumber NW11, and the knots of the lower-layer pre-processing lumber NW12 are likely to penetrate deeply into the pre-surface-layer lumber NW11. This makes it easier for the knots of the lower-layer pre-processing lumber NW12 to approach the design surface D, further increasing the compressibility of the thickness between the hard knots K and the design surface D and further increasing the surface hardness. That is, in the laminated plastically processed timber LPW1 of the first embodiment, the surface layer plastically processed timber PW11 and the lower layer plastically processed timber PW12 that constitute it are laminated and bonded together with the longitudinal direction of the wood grain aligned with each other, so that the knots K of the lower layer plastically processed timber PW12 press heavily against the soft parts without knots of the surface layer plastically processed timber PW11, deforming them, and the knots K of the lower layer unprocessed timber NW12 move closer to the design surface D, thereby increasing the compression rate of the thickness between the hard knots K and the design surface D and further increasing the surface hardness. Also, the variation in surface hardness can be reduced, stabilizing the surface hardness characteristics.

[0100] As described above, preferably, the surface-pre-processed lumber NW11 without knots K has the flat grain or the straight grain side of its surface side facing the design surface D, and the flat grain or the straight grain side of the back side of the wood on the opposite side facing the lower-layer-pre-processed lumber NW12 having knots K. Also, the lower-layer-pre-processed lumber NW12 having knots K has the flat grain or the straight grain side of its back side facing the surface-pre-processed lumber NW11, and the flat grain or the straight grain side of the surface side of the wood on the opposite side facing the design surface D. By heating and compressing the laminated pre-processed lumber LNW1, which is made by stacking pre-processed lumber NW11 without knots and pre-processed lumber NW12 with knots, with the surface side facing away from the design surface, perpendicular to the length of the wood grain, the resistance (compressive stress) generated at the boundary between the pre-processed lumber NW11 and the pre-processed lumber NW12 increases, allowing for greater compression of the design surface D side of the pre-processed lumber NW11 closer to the movable press platen 10A. This makes it possible to increase the compression rate of the design surface D side of the laminated plastically processed lumber LPW1 and increase the surface hardness. Furthermore, the variation in surface hardness can be reduced, resulting in more stable surface hardness characteristics.

[0101] That is, the design surface D side of the surface layer plastically processed wood PW11 that constitutes the laminated plastically processed lumber LPW1 is the plain grain or straight grain side of the wood surface, and the opposite side, the bonding surface with the lower layer plastically processed wood PW12, is the plain grain or straight grain side of the wood back, and the bonding surface with the surface layer plastically processed wood PW11 of the lower layer plastically processed wood PW12 that constitutes the laminated plastically processed lumber LPW1 is the plain grain or straight grain side of the wood back, and the opposite side, the anti-design surface, is the plain grain or straight grain side of the wood surface. In this case, it is possible to increase the compression ratio of the design surface D side of the laminated plastically processed lumber LPW1 and increase the surface hardness. Furthermore, variation in surface hardness can be reduced, and the surface hardness characteristics can be more stabilized.

[0102] Furthermore, since the plain grain or straight grain side of the surface side of the surface plastically processed timber PW11 is the press surface that the movable press platen 10A abuts against, and the plain grain or straight grain side of the surface side of the lower layer plastically processed timber PW12 is the press surface that the fixed press platen 10B abuts against, the wood is compressed in a compression direction that reduces the amount of distortion, internal resistance, and stress due to compression.In addition, since the plain grain or straight grain side of the surface side of the wood is located on the front and back surfaces of the laminated plastically processed timber LPW1, the anisotropy of shrinkage is balanced, even if expansion and contraction forces occur due to changes in ambient environmental conditions such as humidity, moisture, and dryness after compaction processing, distortion is less likely to occur, and the dimensional and shape stability is high.

[0103] Preferably, the lower layer plastically processed wood PW12 having knots K has a maximum value θ of the acute angle (annual ring angle) θ2 formed by the annual ring line GR2 appearing on the butt end surface and the adhesive boundary line BL of the surface layer plastically processed wood PW11 and the lower layer plastically processed wood PW12. max2 The maximum value θ1 of the acute angle between the annual ring line GR1 and the adhesive boundary line BL on the cut end surface of the surface plastically processed wood PW11 without knots K is max1 is larger than (θ max2 >θ max1 ). In other words, the surface plastically processed wood PW11 without knots K has the maximum value θ1 of the acute side intersection angle (annual ring angle) θ1 formed by the annual ring line GR1 appearing on the butt end surface and the adhesive boundary line BL of the surface plastically processed wood PW11 and the lower plastically processed wood PW12. max1 The maximum value θ2 of the acute angle between the annual ring line GR2 and the adhesive boundary line BL on the cut end surface of the lower layer plastically processed wood PW11 containing knot K. max2 It is smaller than

[0104] The maximum value of the acute angle θ2 (annual ring angle) between the annual ring line GR2 appearing on the end grain surface of the lower layer plastically processed wood PW12 containing knots K and the adhesive boundary line BL of the surface layer plastically processed wood PW11 and the lower layer plastically processed wood PW12 is max2The angle θ2 indicates the largest value among the multiple acute-angle crossing angles θ2 formed by the multiple annual ring lines GR2 appearing on the end grain surface of the lower layer plastically processed wood PW12 with knots K and the adhesive boundary line BL. Also, the maximum value θ1 of the acute-angle crossing angle (annual ring angle) θ1 formed by the annual ring line GR1 appearing on the end grain surface of the surface layer plastically processed wood PW11 without knots K and the adhesive boundary line BL. max1 This indicates the largest value of the multiple acute-angle intersection angles θ1 formed by the multiple annual ring lines GR1 that appear on the end grain surface of the surface plastically processed wood PW11 that is free of knots K and the adhesive boundary line BL.

[0105] The maximum value of the annual ring angle θ2 in the lower layer plastically processed wood PW12 with knot K is max2 However, the maximum value of the annual ring angle θ1 in the surface plastically processed wood PW11 without knots K is max1 In the laminated plastically processed timber LPW1 consisting of surface layer plastically processed timber PW11 and lower layer plastically processed timber PW12 larger than the surface layer pre-processed timber NW11, the lower layer pre-processed timber NW12 is less susceptible to compression (has higher compressive strength) than the surface layer pre-processed timber NW11, so the design surface D side of the surface layer plastically processed timber PW11 is strongly compressed. Therefore, the compression ratio of the design surface D side of the laminated plastically processed timber LPW1 can be increased, and the surface hardness can be further increased. Furthermore, the variation in surface hardness can be reduced, and the surface hardness characteristics can be stabilized.

[0106] Furthermore, the maximum value of the annual ring angle θ2 in the lower layer plastically processed wood PW12 with knot K is max2 However, if the angle is preferably within the range of 40° or more and less than 90°, and more preferably 45° or more and 85° or less, the lower layer plastically processed wood PW12 is less likely to be compressed (its compressive strength is high), and therefore the design surface D side of the surface layer plastically processed wood PW11 can be compressed more greatly. In other words, the compression rate of the design surface D side of the laminated plastically processed wood LPW1 can be increased, and the surface hardness can be further increased. Furthermore, the variation in surface hardness can be reduced, and the surface hardness characteristics can be more stabilized.

[0107] In addition, the maximum value of the annual ring angle θ1 in the surface plastically processed wood PW11 without knots K is max1However, if the angle is preferably within the range of 1° or more and 40° or less, and more preferably 1° or more and 35° or less, the surface plastically processed lumber PW11 is easily compressible, and the design surface D side of the surface plastically processed lumber PW11 can be compressed more greatly. In other words, the compression rate of the design surface D side of the laminated plastically processed lumber LPW1 can be increased, and the surface hardness can be further increased. Furthermore, the variation in surface hardness can be reduced, and the surface hardness characteristics can be more stabilized.

[0108] In addition, since the occupancy rate of knots K on the surface of the lower layer plastically processed wood PW12 containing knots K is preferably within the range of 0.5 to 20%, more preferably 1 to 15%, and even more preferably 3 to 15%, cracks, etc. around the knots K are less likely to occur, and the design surface D side of the surface layer plastically processed wood PW11 can be greatly compressed, further increasing the surface hardness, and further reducing the variation in surface hardness and making the surface hardness characteristics more stable.

[0109] In this way, by stacking the knot-free pre-surface-processed wood NW11 on top of the knot-free pre-substrate-processed wood NW12 that has knots underneath, and then heating and compressing them perpendicular to the length of the wood grain, the knots K in the pre-surface-processed wood NW12 are pressed and deformed in the knot-free parts of the pre-surface-processed wood NW11, bringing the knots K closer to the design surface D, and the thickness between the design surface D and the knots K is highly compressed, so that the design surface D side of the pre-surface-processed wood NW11 is more compressed than the adhesive boundary line BL side with the pre-substrate-processed wood NW12.

[0110] In the laminated plastically processed lumber LPW1 of the first embodiment, the Brinell hardness (HB) of the design surface D side of the surface plastically processed lumber PW11 is 10 N / mm 2 More than 50N / mm 2Within this range, cracks and fissures are unlikely to occur around the knots K, and even when used as flooring or the like, heel marks are unlikely to occur. Furthermore, even when used as a tabletop or the like, scratches caused by writing, cutters, or collisions with heavy objects such as desk legs are unlikely to occur, resulting in excellent maintenance of aesthetic appearance. More preferably, the Brinell hardness of the design surface D side of the wood NW11 before surface processing is 25 N / mm 2 More than 50N / mm 2 More preferably, 30 N / mm 2 More than 50N / mm 2 , particularly preferably 35 N / mm 2 More than 50N / mm 2 It is within the following range:

[0111] Furthermore, in the laminated plastically processed wood LPW1 of the first embodiment, the thickness of the surface layer plastically processed wood PW11 is preferably 0.3 to 1.0 times, and more preferably 0.4 to 0.6 times, the thickness of the lower layer plastically processed wood PW12 due to compaction. This thickness makes it difficult for cracks or fractures to occur due to compression, and high surface hardness can be obtained. Furthermore, the variation in surface hardness can be reduced, and the surface hardness characteristics can be more stabilized. Since the surface plastically processed timber PW11 and the lower layer plastically processed timber PW12 can be distinguished from each other by the dense adhesive boundary line BL or by the change in the annual ring lines GR1 and GR2 on the butt end surface, the thickness here is the average thickness measured by separating the surface plastically processed timber PW11 and the lower layer plastically processed timber PW12 at the adhesive boundary line (adhesive boundary line BL). Also, although adhesive is applied between the plastically processed timber PW11 and PW12, the thickness above does not include the thickness of the applied adhesive.

[0112] The laminated plastically processed wood LPW1 of this embodiment 1 has an overall thickness of preferably 10 mm to 40 mm, more preferably 10 mm to 35 mm, and even more preferably 10 mm to 30 mm, the thickness of the surface plastically processed wood PW11 is preferably 3 mm to 20 mm, more preferably 4 mm to 15 mm, and even more preferably 4 mm to 12 mm, and the thickness of the lower layer plastically processed wood PW12 is preferably 5 mm to 25 mm, more preferably 5 mm to 20 mm, and even more preferably 6 mm to 20 mm.Within these ranges, high surface hardness is ensured, but the thin overall thickness makes it lightweight.

[0113] Furthermore, the laminated plastically processed wood LPW1 of this embodiment 1 has a compression ratio of preferably 30% to 70%, more preferably 35% to 70%, relative to the air-dry specific gravity of the wood species of the original unprocessed wood NW, the surface plastically processed wood PW11 has a compression ratio of preferably 50% to 75%, more preferably 55% to 75%, relative to the air-dry specific gravity of the wood species of the original unprocessed wood NW, and the lower layer plastically processed wood PW12 has a compression ratio of preferably 15% to 55%, more preferably 20 to 50%, relative to the air-dry specific gravity of the wood species of the original unprocessed wood NW. Within these compression ratio ranges, lightweight and high surface hardness can be achieved at the same time.

[0114] The compression rate relative to the air-dry specific gravity of the original unprocessed wood NW is calculated from the air-dry specific gravity of the original unprocessed wood NW and the air-dry specific gravity of each plastically processed wood PW11, PW12 after compaction processing, and is obtained from the following formula. Compression rate (%) = [1-{(air-dry specific gravity of original unprocessed wood NW) / (air-dry specific gravity of plastically processed wood PW)}] ×100 The air-dry specific gravity is the specific gravity of wood when it is dried in the air, i.e., when it has reached the air-dry moisture content. It is usually expressed as the specific gravity at a moisture content of 15%, and is a value obtained by comparing the weight of wood when dried with the weight of the same volume of water. The larger the value, the heavier the wood, and the smaller the value, the lighter the wood. The air-dry specific gravity of the surface-layer plastically processed wood PW11 and the bottom-layer plastically processed wood PW12 can be measured by separating the surface-layer plastically processed wood PW11 and the bottom-layer plastically processed wood PW12 at the adhesive boundary line BL.

[0115] In addition, the air-dry specific gravity of the laminated plastically processed lumber LPW1 of the present embodiment 1 is preferably 1.2 to 2.5 times, more preferably 1.5 to 2.0 times, the air-dry specific gravity of the original unprocessed lumber NW. If the specific gravity is within this range, cracks and fractures due to compression are unlikely to occur, and both strength and lightness can be achieved.

[0116] In terms of the compression ratio of the thickness of the unprocessed wood NW11, 12, the laminated plastically processed wood LPW1 of the first embodiment preferably has a compression ratio of 30 to 75%, more preferably 35 to 75%, relative to the thickness of the laminated unprocessed wood LNW1, the surface layer plastically processed wood PW11 has a compression ratio of 50 to 75%, more preferably 55 to 75%, relative to the thickness of the original surface layer unprocessed wood NW11, and the lower layer plastically processed wood PW12 has a compression ratio of 15 to 55%, more preferably 20 to 50%, relative to the thickness of the original lower layer unprocessed wood NW12. Within these compression ratio ranges, lightweight and high surface hardness can be achieved at the same time.

[0117] In this way, in this embodiment 1, a lower layer pre-processed timber NW12 containing knots K is layered underneath a surface layer pre-processed timber NW11 without knots K, via an adhesive, to form a laminated pre-processed timber LNW1, and this laminated pre-processed timber LNW1 is then compacted to form laminated plastically processed timber LPW1.By utilizing the fact that resistance occurs at the boundary between the surface layer pre-processed timber NW11 and the lower layer pre-processed timber NW12 when compressed due to the different types of wood, it is possible to make it easier to compress the design surface D side of the surface layer pre-processed timber NW11 closer to the movable press platen 10A.Furthermore, by utilizing the hardness of the knots K of the lower layer pre-processed timber NW12 layered underneath the surface layer pre-processed timber NW11, the knots K are pushed (reduced) into the surface layer pre-processed timber NW11, and the compressibility of the thickness between the pushed-in (reduced) knots K and the design surface D side is increased, thereby increasing the surface hardness of the laminated plastically processed timber LPW1.

[0118] As explained above, the laminated plastically processed wood LPW1 according to the first embodiment is a laminated plastically processed wood PLW1 in which two pieces of wood, namely, surface layer plastically processed wood PW11 and lower layer plastically processed wood PW12, are laminated and glued together perpendicular to the longitudinal direction of the wood grain, and which has been plastically processed by heating and compressing them perpendicular to the longitudinal direction of the wood grain and then fixing them. The lower layer plastically processed wood PW12 glued underneath the surface layer plastically processed wood PW11 that forms the design surface D has knots K, and due to the heating and compression, the surface layer plastically processed wood PW11 that forms the design surface D is pressed and deformed by the knots K of the lower layer plastically processed wood PW12 glued to it, and the design surface D side of the surface layer plastically processed wood PW11 is compressed more highly than the boundary side with the lower layer plastically processed wood PW12 (the side of the adhesive boundary line BL).

[0119] The laminated plastically processed lumber LPW1 according to the first embodiment is made by stacking two pieces of wood, namely, a surface pre-processed lumber NW11 without knots K and a lower pre-processed lumber NW12 with knots K, and then heat-compressing and compressing them in a direction perpendicular to the length direction of the wood grain, and then fixing them. That is, the laminated pre-processed lumber LNW1, in which the surface pre-processed lumber NW11 and the lower pre-processed lumber NW12 are stacked, is plastically processed (densified), and is heat-compressed in a direction perpendicular to the length direction of the wood grain. During this process, resistance occurs at the boundary between the stacked surface pre-processed wood NW11 and lower layer pre-processed wood NW12, increasing the compression rate on the design surface D side; and, due to the heated compression, the surface plastically processed wood PW11 is pressed and deformed by the knots K of the lower layer plastically processed wood PW12, and the thickness between the hard knots K approaching the design surface D side and the design surface D is highly compressed, resulting in the design surface D side of the surface plastically processed wood PW11 being more compressed than the boundary side with the lower layer plastically processed wood PW12.

[0120] Thus, according to the laminated plastically processed wood LPW1 of the above-mentioned embodiment 1, the laminated structure of the surface plastically processed wood PW11 and the lower layer plastically processed wood PW12, and the hard knot K of the lower layer plastically processed wood PW12 pressingly deforms the surface plastically processed wood PW11 and moves closer to the design surface D, can increase the compression rate of the thickness between the hard knot K and the design surface D, and can increase the surface hardness on the design surface D side.

[0121] In addition, the pressure deformation caused by the knot K means that, when viewed from the end grain surface of the laminated plastically processed timber LPW1, the adhesive boundary line BL between the surface plastically processed timber PW11 and the lower layer plastically processed timber PW12 is bent, and when viewed from the adhesive surfaces (opposing surfaces) of the surface plastically processed timber PW11 and the lower layer plastically processed timber PW12, the knot K is convex on the adhesive surface of the lower layer plastically processed timber PW12, and the part of the adhesive surface of the surface plastically processed timber PW11 that is affected by the knot K of the lower layer plastically processed timber PW12 is deformed into a concave shape.

[0122] Furthermore, in the laminated plastically processed timber LPW1 according to the first embodiment, the surface-layer plastically processed timber PW11 and the lower-layer plastically processed timber PW12 are laminated and bonded together with their grains aligned in the longitudinal direction, so that the surface-layer plastically processed timber PW11 is significantly pressed and deformed by the knots K of the lower-layer plastically processed timber PW12, and the knots K of the lower-layer plastically processed timber PW12 are brought closer to the design surface D of the surface-layer plastically processed timber PW11. This allows for greater compression between the hard knots K and the design surface D, increasing the compression rate on the design surface D side and further increasing the surface hardness, thereby reducing variation in surface hardness and stabilizing the surface hardness characteristics.

[0123] In the laminated plastically processed lumber LPW1 according to the first embodiment, when the surface layer plastically processed lumber PW11 and the lower layer plastically processed lumber PW12 are laminated and bonded together with the plain grain or longitudinal grain surfaces of the backside of the wood facing each other, the anisotropy of the shrinkage rate of the lumber is balanced. Therefore, even if expansion and contraction forces occur due to changes in the surrounding annular conditions, distortion, knots, cracks, etc. are unlikely to occur, and the dimensional and shape stability is high. Furthermore, when heated and compressed perpendicular to the length direction of the wood grain, higher resistance (compressive stress) occurs at the boundary between the laminated lumber pieces, which increases the compression rate on the design surface D. This improves surface hardness, reduces surface hardness variation, and stabilizes surface hardness characteristics.

[0124] That is, in the laminated plastically processed wood LPW1 according to the first embodiment, the design surface D of the surface layer plastically processed wood PW11 is a plain grain surface or a straight grain surface on the front side of the wood, and the opposite surface, which faces the lower layer plastically processed wood PW12, is a plain grain surface or a straight grain surface on the back side of the wood, and the surface of the lower layer plastically processed wood PW12 that faces the surface layer plastically processed wood PW11 is a plain grain surface or a straight grain surface on the back side of the wood. Because the design surface D is the flat grain or straight grain surface on the front side of the wood, it is easily compressed. Furthermore, because the surface plastically processed wood PW11 and the lower layer plastically processed wood PW12 are laminated with the flat grain or straight grain surfaces on the back side of the wood facing each other, the resistance (internal stress) at the boundary between the pieces of wood (bonding boundary line BL) is high when heated and compressed perpendicular to the length of the wood grain, which allows for greater compression of the design surface D side of the surface plastically processed wood PW11. This makes it possible to improve the surface hardness on the design surface D side, reduce variation in surface hardness, and make the surface hardness characteristics more stable.

[0125] However, when carrying out the present invention, the design surface D of the surface-layer plastically processed timber PW11 is the flat grain or straight grain surface on the front side of the wood, and the opposite surface, which faces the lower-layer plastically processed timber PW12, is the flat grain or straight grain surface on the back side of the wood, but the surface of the lower-layer plastically processed timber PW12 facing the surface-layer plastically processed timber PW11 may also be the flat grain or straight grain surface on the front side of the wood. In this case, since the lower-layer plastically processed timber PW12 is easily compressed, even if it has large knots K, it is less likely to break or crack.

[0126] The laminated plastically processed wooden piece LPW1 according to the first embodiment preferably has a Brinell hardness of 10 N / mm on the design surface D side. 2 More than 50N / mm 2 Less than or equal to 25N / mm 2 More than 50N / mm 2 More preferably, 30 N / mm 2 More than 50N / mm 2 , particularly preferably 35 N / mm 2 More than 50N / mm 2This makes it difficult for heel marks to form when used as flooring or the like, and also makes it difficult for scratches caused by writing, cutters, or the like, or scratches caused by heavy objects such as desk legs to collide with it when used as a tabletop or the like, resulting in excellent maintenance of aesthetic appearance.

[0127] The laminated plastically processed timber LPW1 according to the first embodiment preferably has a maximum value θ of the acute angle θ2 formed by the annual ring line GR2 appearing on the end grain surface of the lower-layer plastically processed timber PW12 having knots K and the adhesive boundary line BL of the surface-layer plastically processed timber PW11 and the lower-layer plastically processed timber PW12. max2 The maximum value θ1 of the acute angle between the annual ring line GR1 and the adhesive boundary line BL on the end grain surface of the surface plastically processed wood PW11 without knots K is max1 Therefore, since the lower layer plastically processed wood PW12 is difficult to compress, the compression ratio of the design surface D side of the surface layer plastically processed wood PW11 can be increased, which enables the surface hardness to be improved, the variation in surface hardness to be reduced, and the surface hardness characteristics to be more stabilized.

[0128] The laminated plastically processed timber LPW1 according to the first embodiment has a maximum value θ of the acute angle θ2 formed by the annual ring line GR2 appearing on the end grain surface of the lower-layer plastically processed timber PW12 having knots K and the adhesive boundary line BL of the surface-layer plastically processed timber PW11 and the lower-layer plastically processed timber PW12. max2 is preferably 40° or more and less than 90°, more preferably 45° or more and 85° or less, so that the lower layer plastically processed wood PW12 is difficult to compress, and the compression ratio of the design surface D side of the surface layer plastically processed wood PW11 can be increased. As a result, the surface hardness can be further improved, the variation in surface hardness can be reduced, and the surface hardness characteristics can be more stabilized.

[0129] The laminated plastically processed timber LPW1 according to the first embodiment has a maximum value θ of the acute angle θ1 formed by the annual ring line GR1 appearing on the end grain surface of the surface plastically processed timber PW11 without knots K and the adhesive boundary line BL between the surface plastically processed timber PW11 and the lower plastically processed timber PW12. max1However, since the angle is preferably 1° or more and 40° or less, and more preferably 1° or more and 35° or less, the surface plastically processed lumber PW11 is easily compressible, and the design surface D side of the surface plastically processed lumber PW11 can be compressed more greatly. As a result, the compression ratio of the design surface D side of the laminated plastically processed lumber LPW1 can be increased, and the surface hardness can be further increased. In addition, the variation in surface hardness can be reduced, and the surface hardness characteristics can be more stabilized.

[0130] Furthermore, in the laminated plastically processed wood LPW1 of the above-mentioned embodiment 1, the occupancy rate of knots K on the surface of the lower layer plastically processed wood PW12 having knots K is preferably within the range of 0.5 to 20%, more preferably 1 to 15%, and even more preferably 3 to 15%, thereby ensuring strength that is less susceptible to cracks, fissures, etc., while increasing surface hardness.

[0131] [Embodiment 2] Next, a laminated plastically processed wooden piece LPW2 according to a second embodiment of the present invention will be described with reference to FIG. The laminated plastically processed lumber LPW2 of this embodiment 2 is made by stacking three or more pieces (three pieces) of unprocessed lumber NW11, NW12, NW13, ..., NWn perpendicular to the length direction of the grain using adhesive, and plastically processing (compacting) them by heating, compressing and fixing them perpendicular to the length direction of the grain. In this second embodiment, cedar or cypress wood is also used for the three or more pieces of raw lumber NW11, NW12, NW13, ..., NWn. That is, the plastically processed lumber PW11, PW12, PW13, ..., PWn that make up the laminated plastically processed lumber LPW2 are made of cedar or cypress wood.

[0132] The laminated plastically processed timber LPW2 of this embodiment 2 uses surface layer pre-processed timber NW11 that is knot-free on the surface layer that faces the design surface D, and layers lower layer pre-processed timber NW12 that has one or more knots directly below the knot-free surface layer pre-processed timber NW1. One or more other pieces of pre-processed timber NW13, ..., NWn are then layered below the lower layer pre-processed timber NW12. The knot-free surface layer pre-processed timber NW11, the knot-free lower layer pre-processed timber NW12, and the one or more other pieces of pre-processed timber NW13, ..., NWn are stacked in the thickness direction, which is perpendicular to the length direction of the wood grain, and are then compacted by heat compression treatment and compression fixation treatment perpendicular to the length direction of the wood grain. The laminated plastically processed timber LPW2 is made up of surface layer plastically processed timber PW11 that is knot-free, lower layer plastically processed timber PW12 that has knots, and one or more other pieces of plastically processed timber PW13, ..., PWn that are stacked and bonded together.

[0133] In Figure 5, the laminated plastically processed lumber LPW2 of this embodiment 2 is described as an example in which another piece of unprocessed lumber NW13 is placed under the lower layer of unprocessed lumber NW12, and the three pieces of unprocessed lumber NW11, NW12, and NW13 are stacked perpendicular to the length direction of the grain using adhesive, and plastically processed by heating, compressing, and fixing perpendicular to the length direction of the grain. One or more other pieces of unprocessed wood NW13,...,NWn that are stacked under the lower layer unprocessed wood NW12, i.e., one or more other pieces of plastically processed wood PW13,...,PWn that are stacked under the lower layer plastically processed wood PW12, may or may not have knots K.

[0134] In the second embodiment as well, the surface layer unprocessed timber NW11 without knots K and the lower layer unprocessed timber NW12 with knots K are stacked perpendicular to the length direction of the wood grain with the length direction of the wood grain aligned. Furthermore, one or more other pieces of unprocessed timber NW13, ..., NWn to be stacked below the lower layer unprocessed timber NW12 are also stacked perpendicular to the length direction of the wood grain with the length direction of the wood grain aligned with the length direction of the surface layer unprocessed timber NW11 and the lower layer unprocessed timber NW12. That is, the laminated plastically processed timber LPW2 of this embodiment 2 is made up of surface layer plastically processed timber PW11, lower layer plastically processed timber PW12, and one or more other pieces of plastically processed timber PW13, ..., PWn, which are stacked and glued together with their grains aligned in the longitudinal direction.

[0135] In the laminated plastically processed lumber LPW2 of the second embodiment, wood without knots K is used for the surface layer pre-processed lumber NW11 that serves as the raw material, and wood with knots K is used for the lower layer pre-processed lumber NW12, but preferably, flat grain lumber or straight grain lumber is used for the surface layer pre-processed lumber NW11 that does not have knots K and the lower layer pre-processed lumber NW12 that has knots K. Furthermore, flat grain lumber or straight grain lumber is preferably used for another one or more pieces of pre-processed lumber NW13, ..., NWn that are layered under the lower layer pre-processed lumber NW12. That is, the surface layer plastically processed timber PW11 and the lower layer unprocessed timber PW12 constituting the laminated plastically processed timber LPW2 of the present embodiment 2 are preferably flat grain timber or straight grain timber. One or more other pieces of plastically processed timber PW13, ..., PWn overlapping the lower layer plastically processed timber PW12 are also preferably flat grain timber or straight grain timber.

[0136] Also in this second embodiment, preferably, as shown in FIG. 5, the surface pre-processed lumber NW11 without knots K has the flat grain or longitudinal side of its front side facing the design surface D, and the flat grain or longitudinal side of the back side of the wood on the opposite side facing the lower pre-processed lumber NW12 with knots K, and the flat grain or longitudinal side of the back side of the lower pre-processed lumber NW12 with knots K faces the surface pre-processed lumber NW11, and the flat grain or longitudinal side of the front side of the wood on the opposite side faces the other pre-processed lumber NW13 that is placed underneath, and the surface pre-processed lumber NW11 without knots K and the lower pre-processed lumber NW12 with knots K are stacked in their thickness direction.

[0137] Regarding another piece of unprocessed wood NW13 that is stacked under the lower layer unprocessed wood NW12, the side facing the lower layer unprocessed wood NW12 may be the plain grain or straight grain side of the front side of the wood, or the plain grain or straight grain side of the back side of the wood. When laminated plastically processed timber LPW2 is composed of surface layer plastically processed timber PW11, lower layer plastically processed timber PW12, and another piece of plastically processed timber PW13 stacked underneath, that is, when three pieces of pre-processed timber NW11, NW12, and NW13, namely surface layer pre-processed timber NW11, lower layer pre-processed timber NW12, and another piece of pre-processed timber NW13 stacked underneath the lower layer pre-processed timber NW12, are compressed to form laminated plastically processed timber LPW2, it is preferable that, as shown in Figure 5, the flat grain or longitudinal side of the back of the other piece of pre-processed timber NW13 stacked underneath the lower layer pre-processed timber NW12 be the opposing surface (adhesive surface) to the lower layer pre-processed timber NW12, and the flat grain or longitudinal side of the front of the wood be the opposite design surface. If the counter-design surface of another piece of unprocessed wood NW13, which is opposite the design surface D of the surface layer unprocessed wood NW11, is the plain grain or longitudinal grain side of the wood surface, the press surface that the fixed press platen 10B abuts will be the plain grain or longitudinal grain side of the wood surface, and the wood will be compressed in a compression direction with less distortion, internal resistance, and stress due to compression. Therefore, the unprocessed wood NW13, which is layered under the lower layer unprocessed wood NW12 and forms the counter-design surface, will be more likely to compress, and even if it has knots K, it will be less likely to break or crack during compression. In other words, in the case of stacking three pieces of wood, it is preferable that the side of another piece of pre-processed wood NW13 that is placed underneath the lower layer pre-processed wood NW12 be the flat grain or straight grain side on the back side of the wood, and the flat grain or straight grain side on the opposite side be the press surface.This makes it easier for the other piece of pre-processed wood NW13, which is on the side opposite the design surface D of the surface layer pre-processed wood NW11, to be compressed, making it less likely to apply load to the knots K of the lower layer pre-processed wood NW12 and preventing the knots K from cracking.

[0138] If there is an odd number of sheets of plastically processed wood PW13,...,PWn overlapping the lower layer pre-plasticized wood PW12, i.e., if the entire laminated plastically processed wood LPW2 is made up of an odd number of sheets, it is preferable that the counter-design surface of the back layer of plastically processed wood PW13,...,PWn opposite the design surface D of the pre-surface-processed wood NW11 be the flat grain or straight grain side of the wood surface. As a result, since the plastically processed wood PW13,...,PWn forming the counter-design surface is easily compressed, even if it contains knots K, it is less likely to break or crack during compression. However, when carrying out the present invention, the unprocessed wood NW13 that is overlapped under the lower layer unprocessed wood NW12 and forms the opposite design surface may have the flat grain or longitudinal side on the front side of the wood as the surface facing (bonding surface) with the lower layer unprocessed wood NW12, and the flat grain or longitudinal side on the back side of the wood as the opposite design surface. In other words, the opposite design surface of the plastically processed wood PW13 opposite to the design surface D of the surface layer unprocessed wood NW11 may be the flat grain or longitudinal side on the back side of the wood.

[0139] In the second embodiment, the surface layer unprocessed lumber NW11 without knots K is used as the surface layer (upper layer), the lower layer unprocessed lumber NW12 with knots K is stacked under the surface layer unprocessed lumber NW11, and one or more other unprocessed lumber NW13, ..., NWn are stacked under that. At this time, adhesive is applied between the lumber pieces to form a laminated unprocessed lumber LNW2, and three or more unprocessed lumber pieces NW11, NW12, NW13, ..., NWn are stacked. The laminated pre-processed wood LNW2 consisting of the above is heated and compressed in the thickness direction, i.e., perpendicular to the length direction of the grain of the pre-processed wood NW11, NW12, NW13, ..., NWn, and the compression is fixed to form laminated plastically processed wood LPW2 consisting of surface layer plastically processed wood PW11, lower layer plastically processed wood PW12, and one or more other sheets of plastically processed wood PW13, ..., PWn, which are laminated and bonded together.

[0140] Here, in the second embodiment, too, when the knot-free unprocessed lumber NW11 is stacked as the surface layer (upper layer) and the knot-free unprocessed lumber NW12 is stacked as the lower layer, and these lumber pieces are heated and compressed perpendicular to the longitudinal direction of the wood grain, resistance (compressive stress) occurs at the boundary between the unprocessed lumber NW11 and the lower layer, due to the different wood structures (discontinuous wood structure) between them, and the design surface D side of the unprocessed lumber NW11 closer to the movable press platen 10A can be significantly compressed. Furthermore, because the knots K of the lower layer, unprocessed lumber NW12 are hard, the softer portions of the unprocessed lumber NW11, which are knot-free, are pressed and deformed, bringing the knots K closer to the design surface D side. Furthermore, because the knots K are hard, the thickness between the hard knots K and the design surface D can be significantly compressed. This increases the compression rate on the design surface D side, thereby increasing the surface hardness.

[0141] Also in the second embodiment, the knot-free pre-surface-layer lumber NW11 and the knot-free pre-lower-layer lumber NW12 are laminated perpendicular to the grain direction with their grain lengths aligned, and the knots of the lower-layer pre-processing lumber NW12 are likely to press and deform the soft knot-free portions of the pre-surface-layer lumber NW11, and the knots of the lower-layer pre-processing lumber NW12 are likely to penetrate deeply into the pre-surface-layer lumber NW11. This makes it easier for the knots of the lower-layer pre-processing lumber NW12 to approach the design surface D, further increasing the compressibility of the thickness between the hard knots K and the design surface D and further increasing the surface hardness. That is, in the laminated plastically processed timber LPW2 of the second embodiment, the surface layer plastically processed timber PW11 and the lower layer plastically processed timber PW12 that constitute it are laminated and glued together with the longitudinal direction of the wood grain aligned with each other, so that the knots K of the lower layer plastically processed timber PW12 press heavily against the soft parts without knots of the surface layer plastically processed timber PW11, deforming them, and the knots K of the lower layer unprocessed timber NW12 move closer to the design surface D, thereby increasing the compression rate of the thickness between the hard knots K and the design surface D and further increasing the surface hardness. Furthermore, the variation in surface hardness can be reduced, and the surface hardness characteristics can be stabilized.

[0142] In addition, when the design surface D side of the surface plastically processed wood PW11 that constitutes the laminated plastically processed wood LPW2 is the plain grain or straight grain side of the wood surface, and the opposite side, the bonding surface side opposite to the lower layer plastically processed wood PW12, is the plain grain or straight grain side of the wood back side, and the bonding surface side opposite to the surface plastically processed wood PW11 of the lower layer plastically processed wood PW12 is the plain grain or straight grain side of the wood back side, and the plain grain or straight grain side of the opposite side is the bonding surface side opposite to another piece of plastically processed wood PW13 that is overlapping it, the resistance (compressive stress) that occurs at the boundary between the surface plastically processed wood PW11 and the lower layer plastically processed wood PW12 is higher, making it possible to further increase the compression rate of the design surface D side of the laminated plastically processed wood LPW2 and further increase the surface hardness. Furthermore, the variation in surface hardness can be reduced, and the surface hardness characteristics can be more stabilized.

[0143] Furthermore, when the plain grain or straight grain side of the surface of the surface-layered plastically processed timber PW11 is the press surface that the movable press platen 10A abuts against, and when the plain grain or straight grain side of the surface of another piece of plastically processed timber PW13 is the press surface that the fixed press platen 10B abuts against, the timber is compressed in a compression direction that results in less distortion, internal resistance, and stress due to compression.In addition, since the plain grain or straight grain side of the surface of the timber is located on the front and back surfaces of the laminated plastically processed timber LPW2, the anisotropy of shrinkage is balanced, even if expansion and contraction forces occur due to changes in ambient conditions such as humidity, moisture, and dryness after compaction processing, distortion is less likely to occur, and the dimensional and shape stability is high. In addition, if the opposite design surface of the plastically processed wood PW13 on the opposite side to the design surface D of the surface plastically processed wood PW11 is the plain grain or straight grain side of the wood surface, the plastically processed wood PW13 forming the opposite design surface is easily compressed, so even if there is a knot K, it is less likely to crack or break during compression.

[0144] Also in the second embodiment, preferably, the maximum value θ of the acute angle (annual ring angle) θ2 formed by the annual ring line GR2 appearing on the end grain surface of the lower layer plastically processed wood PW12 having knots K and the adhesive boundary line BL of the surface layer plastically processed wood PW11 and the lower layer plastically processed wood PW12 max2The maximum value θ1 of the acute angle between the annual ring line GR1 and the adhesive boundary line BL on the end grain surface of the surface plastically processed wood PW11 without knots K is max1 is larger than (θ max2 >θ max1 ). The maximum value of the annual ring angle θ2 in the lower layer plastically processed wood PW12 with knot K is max2 However, the maximum value of the annual ring angle θ1 in the surface plastically processed wood PW11 without knots K is max1 In the laminated plastically processed timber LPW2 consisting of surface-layer plastically processed timber PW11 and lower-layer plastically processed timber PW12 larger than the surface-layer plastically processed timber PW11, the lower-layer plastically processed timber PW12 is more difficult to compress (has higher compressive strength) than the surface-layer plastically processed timber PW11, so the design surface D side of the surface-layer plastically processed timber PW11 is strongly compressed. Therefore, the compression ratio of the design surface D side of the laminated plastically processed timber LPW2 can be increased, and the surface hardness can be further increased. Furthermore, the variation in surface hardness can be reduced, and the surface hardness characteristics can be stabilized.

[0145] In the second embodiment, the maximum value θ of the annual ring angle θ2 in the lower layer plastically processed wood PW12 having the knot K max2 However, if the angle is preferably in the range of 40° or more and less than 90°, and more preferably 45° or more and 85° or less, the lower layer plastically processed wood PW12 is more resistant to compression (has high compressive strength), and the design surface D side of the surface layer plastically processed wood PW11 can be compressed more significantly. This makes it possible to further increase the compression rate of the design surface D side of the laminated plastically processed wood LPW2 and further increase the surface hardness. Furthermore, variation in surface hardness can be reduced, and the surface hardness characteristics can be more stabilized.

[0146] Also in the second embodiment, the maximum value θ of the annual ring angle θ1 in the surface plastically processed lumber PW11 without knots K max1However, if the angle is preferably in the range of 1° or more and 40° or less, and more preferably 1° or more and 35° or less, the surface plastically processed timber PW11 is more easily compressed, and the design surface D side of the surface plastically processed timber PW11 can be compressed more greatly. Therefore, the compression ratio of the design surface D side of the laminated plastically processed timber LPW2 can be increased, and the surface hardness can be further increased. Furthermore, the variation in surface hardness can be reduced, and the surface hardness characteristics can be more stabilized.

[0147] Furthermore, in this embodiment 2, the occupancy rate of knots K on the surface of the lower layer plastically processed wood PW12 containing knots K is preferably within the range of 0.5 to 20%, more preferably 1 to 15%, and even more preferably 3 to 15%, which makes it less likely for cracks, fissures, etc. to occur around the knots K, and allows the design surface D side of the surface layer plastically processed wood PW11 to be greatly compressed, thereby further increasing the surface hardness, and further reducing the variation in surface hardness and making the surface hardness characteristics more stable.

[0148] In this second embodiment, too, a surface layer of pre-processed wood NW11 without knots K is stacked on top of a lower layer of pre-processed wood NW12 with knots K, and then one or more pieces of pre-processed wood NW13, ..., NWn are stacked underneath that, and these pieces are heated and compressed perpendicular to the length direction of the wood grain.This causes the knot-free parts of the surface layer of pre-processed wood NW11 to be pressed and deformed by the knots K of the lower layer of pre-processed wood NW12, bringing the knots K closer to the design surface D, and the thickness between the design surface D and the knots K is highly compressed, so that the design surface D side of the surface layer of pre-processed wood NW11 is more compressed than the adhesive boundary line BL side with the lower layer of pre-processed wood NW12.

[0149] In the laminated plastically processed lumber LPW2 of the second embodiment, the Brinell hardness (HB) of the design surface D side of the surface plastically processed lumber PW11 is 10 N / mm 2 More than 50N / mm 2Within this range, cracks and fissures are unlikely to occur around the knots K, and even when used as flooring or the like, heel marks are unlikely to occur. Furthermore, even when used as a tabletop or the like, scratches caused by writing, cutters, or collisions with heavy objects such as desk legs are unlikely to occur, resulting in excellent maintenance of aesthetic appearance. More preferably, the Brinell hardness of the design surface D side of the wood NW11 before surface processing is 25 N / mm 2 More than 50N / mm 2 More preferably, 30 N / mm 2 More than 50N / mm 2 , particularly preferably 35 N / mm 2 More than 50N / mm 2 It is within the following range:

[0150] Furthermore, in the laminated plastically processed wood LPW2 of the second embodiment, the thickness of the surface layer plastically processed wood PW11 is preferably 0.3 to 1.0 times, and more preferably 0.4 to 0.6 times, the thickness of the lower layer plastically processed wood PW12 due to compaction. This thickness makes it difficult for cracks or fractures to occur due to compression, and high surface hardness can be obtained. Furthermore, the variation in surface hardness can be reduced, and the surface hardness characteristics can be more stabilized. At this time, the thickness of the plastically processed wood PW13 on the opposite design surface side is easily compressed by the fixed side press platen 10B, so it is preferably in the range of 0.4 to 1.0 times, more preferably 0.5 to 0.9 times, the thickness of the lower layer plastically processed wood PW12, and preferably in the range of 1.0 to 2.0 times, more preferably 1.2 to 1.8 times, the thickness of the surface layer plastically processed wood PW11.

[0151] For example, in Figure 5, the laminated plastically processed wood LPW2 of this embodiment 2 is preferably in the range of 10 mm or more and 40 mm or less, more preferably 10 mm or more and 35 mm or less, and even more preferably 10 mm or more and 30 mm or less, the thickness of the surface plastically processed wood PW11 is preferably in the range of 3 mm or more and 20 mm or less, more preferably 4 mm or more and 15 mm or less, and even more preferably 4 mm or more and 12 mm or less, the thickness of the lower layer plastically processed wood PW12 is preferably in the range of 5 mm or more and 25 mm or less, more preferably 5 mm or more and 20 mm or less, and even more preferably 6 mm or more and 20 mm or less, and the thickness of one piece of plastically processed wood PW13 that overlaps the lower layer plastically processed wood PW12 and forms the opposite design surface is preferably in the range of 4 mm or more and 20 mm or less, preferably 5 mm or more and 19 mm or less, and even more preferably 6 mm or more and 18 mm or less. Within this range, a high surface hardness is ensured, but the overall thickness is thin and lightweight.

[0152] Furthermore, in the laminated plastically processed wood LPW2 of this second embodiment, the compression ratio relative to the air-dry specific gravity of the wood species of the original unprocessed wood NW is preferably 30% to 70%, more preferably 35% to 70%, while the compression ratio relative to the air-dry specific gravity of the wood species of the original unprocessed wood NW of the surface layer plastically processed wood PW11 is preferably 50% to 75%, more preferably 55% to 75%, and the compression ratio relative to the air-dry specific gravity of the wood species of the original unprocessed wood NW of the lower layer plastically processed wood PW12 is preferably 15% to 55%, more preferably 20 to 50%. Within these compression ratio ranges, both light weight and high surface hardness can be achieved. At this time, the compression rate of the plastically processed wood PW13 forming the counter-design surface is preferably 20% to 60%, more preferably 25% to 50%, relative to the air-dry specific gravity of the original unprocessed wood NW13.

[0153] Additionally, the air-dry specific gravity of the laminated plastically processed lumber LPW2 of the second embodiment is preferably in the range of 1.2 to 2.5 times, more preferably 1.5 to 2.0 times, the air-dry specific gravity of the original unprocessed lumber NW. If the specific gravity is within this range, cracks and fractures due to compression are unlikely to occur, and both strength and lightness can be achieved.

[0154] In addition, in terms of the compression ratio from the thickness of the pre-processed wood NW11, 12, 13, the laminated plastically processed wood LPW2 of this embodiment 2 has a compression ratio relative to the overall thickness of the laminated pre-processed wood LNW2, which is preferably in the range of 30 to 75%, more preferably in the range of 35 to 75%; the surface layer plastically processed wood PW11 has a compression ratio relative to the thickness of the original surface layer pre-processed wood NW11, which is preferably in the range of 50% to 75%, more preferably in the range of 55% to 75%; the lower layer plastically processed wood PW12 has a compression ratio relative to the thickness of the original lower layer pre-processed wood NW12, which is preferably in the range of 15% to 55%, more preferably in the range of 20 to 50%; and the other plastically processed wood PW13 has a compression ratio relative to the thickness of the original other pre-processed wood NW13, which is preferably in the range of 20% to 55%, more preferably in the range of 25 to 50%. Within this range of compression ratio, both light weight and high surface hardness can be achieved.

[0155] In this way, in the second embodiment, the lower layer pre-processed lumber NW12 having knots K is layered under the surface layer pre-processed lumber NW11 without knots K, via an adhesive, and one or more other pre-processed lumber NW13, . . . , NWn is layered under that to form the laminated pre-processed lumber LNW2, and the laminated pre-processed lumber LNW2 is compacted to form the laminated plastically processed lumber LPW2. Also in the second embodiment, since the surface layer pre-processed lumber NW11 and the lower layer pre-processed lumber NW12 are different wood materials, By utilizing the resistance that occurs at the boundary between them during compression, it is made easier to compress the design surface D side of the pre-surface-processed wood NW11 that is closer to the movable press platen 10A, and further by utilizing the hardness of the knots K of the lower pre-surface-processed wood NW12 that is stacked below the pre-surface-processed wood NW11, the knots K are made to bite (reduced) into the pre-surface-processed wood NW11, and by increasing the compression rate of the thickness between the bitten (reduced) knots K and the design surface D side, the surface hardness of the laminated plastically processed wood LPW2 is increased.

[0156] As explained above, the laminated plastically processed wood LPW2 according to the second embodiment is a laminated plastically processed wood LPW2 in which three or more pieces of wood, namely, surface layer plastically processed wood PW11, lower layer plastically processed wood PW12, and other plastically processed wood PW13, ..., PWn, are laminated and glued together perpendicular to the longitudinal direction of the wood grain, and which has been plastically processed by thermal compression and fixation perpendicular to the longitudinal direction of the wood grain. The lower layer plastically processed wood PW12, which is glued below the surface layer plastically processed wood PW11 that forms the design surface D, has knots K, and the surface layer plastically processed wood PW11 that forms the design surface D is pressed and deformed by the knots K of the lower layer plastically processed wood PW12 glued to it through thermal compression, so that the design surface D side of the surface layer plastically processed wood PW11 is more compressed than the boundary side with the lower layer plastically processed wood PW12 (the side of the adhesive boundary line BL).

[0157] The laminated plastically processed lumber LPW2 according to the second embodiment is made by stacking three or more pieces of wood, namely, a surface layer pre-processed lumber NW11, a lower layer pre-processed lumber NW12, and other pre-processed lumber NW13, . . ., NWn, and then heating and compressing and fixing them in a direction perpendicular to the length direction of the wood grain. In other words, the laminated pre-processed lumber LNW2 is made by stacking the surface layer pre-processed lumber NW11, the lower layer pre-processed lumber NW12, and one or more other pre-processed lumber NW13, . . ., NWn, and plastically processing the laminated pre-processed lumber LNW2. When heated and compressed perpendicular to the direction, resistance occurs at the boundary between the stacked surface pre-processed wood NW11 and lower layer pre-processed wood NW12, which increases the compression rate on the design surface D side.In addition, due to the heated compression, the surface plastically processed wood PW11 is pressed and deformed by the knots K of the lower layer plastically processed wood PW12, and the thickness between the hard knots K approaching the design surface D side and the design surface D is highly compressed, so that the design surface D side of the surface plastically processed wood PW11 is more compressed than the boundary side with the lower layer plastically processed wood PW12.

[0158] Thus, according to the laminated plastically processed wood LPW2 of the above-mentioned embodiment 2, the laminated structure of the surface layer plastically processed wood PW11, the lower layer plastically processed wood PW12, and other plastically processed wood PW13, ..., PWn, and the hard knot K of the lower layer plastically processed wood PW12 presses and deforms the surface layer plastically processed wood PW11 and moves closer to the design surface D, thereby increasing the compression rate of the thickness between the hard knot K and the design surface D and increasing the surface hardness on the design surface D side.

[0159] Furthermore, in the laminated plastically processed timber LPW2 according to the second embodiment, the surface-layer plastically processed timber PW11 and the lower-layer plastically processed timber PW12 are laminated and bonded together with their grains aligned along the lengthwise direction, so that the surface-layer plastically processed timber PW11 is significantly pressed and deformed by the knots K of the lower-layer plastically processed timber PW12, and the knots K of the lower-layer plastically processed timber PW12 are brought closer to the design surface D of the surface-layer plastically processed timber PW11. This allows for greater compression between the hard knots K and the design surface D, further increasing the compression rate on the design surface D side and further increasing the surface hardness, thereby reducing variation in surface hardness and stabilizing the surface hardness characteristics.

[0160] In the laminated plastically processed lumber LPW2 according to the second embodiment, when the surface layer plastically processed lumber PW11 and the lower layer plastically processed lumber PW12 are laminated and bonded together with the plain grain or longitudinal grain surfaces of the backside of the wood facing each other, the anisotropy of the shrinkage rate of the lumber is balanced. Therefore, even if expansion and contraction forces occur due to changes in the surrounding annular conditions, distortion, knots, cracks, etc. are unlikely to occur, and the dimensional and shape stability is high. Furthermore, when heated and compressed perpendicular to the length direction of the wood grain, higher resistance (compressive stress) occurs at the boundary between the laminated lumber pieces, which increases the compression rate on the design surface D. This improves surface hardness, reduces surface hardness variation, and stabilizes surface hardness characteristics.

[0161] That is, in the laminated plastically processed wood LPW2 according to the second embodiment, the design surface D of the surface layer plastically processed wood PW11 is a plain grain surface or a straight grain surface on the front side of the wood, and the opposite surface, which faces the lower layer plastically processed wood PW12, is a plain grain surface or a straight grain surface on the back side of the wood, and the surface of the lower layer plastically processed wood PW12 facing the surface layer plastically processed wood PW11 is a plain grain surface or a straight grain surface on the back side of the wood. The design surface D of the surface plastically processed lumber PW11 is easily compressed because it is the flat grain or straight grain surface on the front side of the wood, and furthermore, because the surface plastically processed lumber PW11 and the lower layer plastically processed lumber PW12 are laminated with the flat grain or straight grain surfaces on the back side of the wood facing each other, the resistance (internal stress) at the boundary between the pieces of wood (bonding boundary line BL) is high when heated and compressed perpendicular to the length direction of the wood grain, which allows for greater compression of the design surface D side of the surface plastically processed lumber PW11. This makes it possible to improve the surface hardness of the design surface D side, reduce variation in surface hardness, and more stabilize the surface hardness characteristics.

[0162] In the laminated plastically processed wood LPW2 according to the second embodiment, the Brinell hardness of the design surface D side is preferably 10 N / mm 2 More than 50N / mm 2 Less than or equal to 25N / mm 2 More than 50N / mm 2 More preferably, 30 N / mm 2More than 50N / mm 2 , particularly preferably 35 N / mm 2 More than 50N / mm 2 This makes it difficult for heel marks to form when used as flooring or the like, and also makes it difficult for scratches caused by writing, cutters, or the like, or scratches caused by heavy objects such as desk legs to collide with it when used as a tabletop or the like, resulting in excellent maintenance of aesthetic appearance.

[0163] In the laminated plastically processed timber LPW2 according to the second embodiment, preferably, the lower layer plastically processed timber PW12 having the knot K has a maximum value θ of the acute angle θ2 formed by the annual ring line GR2 appearing on the butt end surface and the adhesive boundary line BL of the surface layer plastically processed timber PW11 and the lower layer plastically processed timber PW12. max2 The maximum value θ1 of the acute angle between the annual ring line GR1 and the adhesive boundary line BL on the end grain surface of the surface plastically processed wood PW11 is max1 Therefore, since the lower layer plastically processed wood PW12 is difficult to compress, the compression ratio of the design surface D of the surface layer plastically processed wood PW11 can be increased, which enables the surface hardness to be improved, and the variation in surface hardness can be reduced, resulting in more stable surface hardness characteristics.

[0164] The laminated plastically processed timber LPW2 according to the second embodiment has a maximum value θ of the acute angle θ2 formed by the annual ring line GR2 appearing on the end grain surface of the lower-layer plastically processed timber PW12 having knots K and the adhesive boundary line BL of the surface-layer plastically processed timber PW11 and the lower-layer plastically processed timber PW12. max2 is preferably 40° or more and less than 90°, more preferably 45° or more and 85° or less, so that the lower layer plastically processed wood PW12 is difficult to compress, and the compression ratio of the design surface D side of the surface layer plastically processed wood PW11 can be increased. As a result, the surface hardness can be further improved, the variation in surface hardness can be reduced, and the surface hardness characteristics can be more stabilized.

[0165] The laminated plastically processed timber LPW2 according to the second embodiment has a maximum value θ of the acute angle θ1 formed by the annual ring line GR1 appearing on the end grain surface of the surface plastically processed timber PW11 without knots K and the adhesive boundary line BL of the surface plastically processed timber PW11 and the lower plastically processed timber PW12. max1 However, since the angle is preferably 1° or more and 40° or less, and more preferably 1° or more and 35° or less, the surface plastically processed lumber PW11 is easily compressible, and the design surface D side of the surface plastically processed lumber PW11 can be compressed more greatly. As a result, the compression ratio of the design surface D side of the laminated plastically processed lumber LPW1 can be increased, and the surface hardness can be further increased. In addition, the variation in surface hardness can be reduced, and the surface hardness characteristics can be more stabilized.

[0166] Furthermore, in the laminated plastically processed wood LPW2 according to the above-mentioned embodiment 2, the occupancy rate of knots K on the surface of the lower layer plastically processed wood PW12 having knots K is preferably within the range of 0.5 to 20%, more preferably 1 to 15%, and even more preferably 3 to 15%, thereby ensuring strength that is less susceptible to cracks, fissures, etc., while reducing variation in surface hardness and stabilizing the surface hardness characteristics.

[0167] [Embodiment 3] Next, a laminated plastically processed wooden piece LPW3 according to a third embodiment of the present invention will be described with reference to FIG. The laminated plastically processed lumber LPW3 of this embodiment 3 is made by stacking two pieces (two pieces) of unprocessed lumber NW1 and NW2 perpendicular to the length direction of the grain using adhesive, and then plastically processing (compacting) them by heating, compressing, and fixing them perpendicular to the length direction of the grain. In this third embodiment, the two pieces of unprocessed wood NW1 and unprocessed wood NW2 are both made of cedar or cypress. That is, the surface layer plastically processed wood PW11 and the lower layer plastically processed wood PW12 that make up the laminated plastically processed wood LPW3 are made of cedar or cypress.

[0168] In detail, the laminated plastically processed timber LPW3 of this embodiment 3 uses pre-surface-processed timber NW11 having one or more knots K on the surface layer facing the design surface D, and layers pre-processed lower layer timber NW12 (pre-backside-processed timber NW12) without knots K underneath the pre-surface-processed timber NW1 having knots K. In other words, the pre-surface-processed timber NW11 having knots K and the pre-processed lower layer timber NW12 without knots K are stacked in the thickness direction, which is perpendicular to the length direction of the wood grain, and then compacted by heat compression treatment and compression fixation treatment perpendicular to the length direction of the wood grain, and consists of surface-layer plastically processed timber PW11 having knots K and lower layer plastically processed timber PW12 without knots K, which are stacked and glued together.

[0169] In the laminated plastically processed timber LPW3 of this third embodiment, wood having knots K is used for the surface layer pre-processing timber NW11 that serves as the raw material, and wood without knots K is used for the lower layer pre-processing timber NW12, but preferably, flat grain timber or straight grain timber is used for the surface layer pre-processing timber NW11 having knots K and the lower layer pre-processing timber NW12 without knots K. In other words, the surface layer plastically processed timber PW11 and the lower layer pre-processing timber PW12 that constitute the laminated plastically processed timber LPW3 are preferably flat grain timber or straight grain timber.

[0170] More preferably, as shown in FIG. 6, the pre-surface-processed lumber NW11 having knots K has the flat grain or longitudinal side of its front surface facing the design surface D, and the flat grain or longitudinal side of the back surface of the opposite side facing the knot-free pre-processed lumber NW12; and the pre-surface-processed lumber NW11 having knots K and the pre-substrate-processed lumber NW12 having knots K are stacked in the thickness direction, with the flat grain or longitudinal side of the back surface of the lower layer pre-processed lumber NW12 having knots K facing the pre-surface-processed lumber NW11, and the flat grain or longitudinal side of the front surface of the opposite side facing the design surface.

[0171] Furthermore, in this third embodiment, the surface layer unprocessed timber NW11 having knots K and the lower layer unprocessed timber NW12 without knots K are laminated perpendicular to the length direction of the wood grain with their grains aligned along the length direction. That is, the laminated plastically processed timber LPW3 of this third embodiment is also formed by laminating and bonding the surface layer plastically processed timber PW11 and the lower layer plastically processed timber PW12 that constitute it with their grains aligned along the length direction.

[0172] In this embodiment 3, the surface layer pre-processed wood NW11 containing knots K is used as the surface layer (upper layer), and the lower layer pre-processed wood NW12 without knots K is stacked underneath the surface layer pre-processed wood NW11 to form the lower layer (back layer).At this time, adhesive is applied between the two pieces of pre-processed wood NW11 and NW12, and the laminated pre-processed wood LNW3 is formed by stacking them together.The laminated pre-processed wood LNW3, consisting of two pieces of pre-processed wood NW11 and NW12, is then heated and compressed in the thickness direction, i.e., perpendicular to the length direction of the grain of the pre-processed wood NW11 and NW12, and a compaction process (plastic processing) is performed to fix the compression, thereby forming laminated plastically processed wood LPW3 consisting of the surface layer plastically processed wood PW11 and the lower layer plastically processed wood PW12, which are stacked and bonded together.

[0173] Here, when the pre-surface-layer-processed lumber NW11 containing knots K is stacked as the surface layer (upper layer) and the pre-lower-layer-processed lumber NW12 without knots K is stacked as the lower layer (back layer), and these are heated and compressed perpendicular to the length direction of the wood grain, resistance (compressive stress) occurs at the boundary between the pre-surface-layer-processed lumber NW11 and the pre-lower-layer-processed lumber NW12 due to the different wood structures (the wood structures are discontinuous), and this allows for significant compression of the design surface D side of the pre-surface-layer-processed lumber NW11 closer to the movable press platen 10A. Furthermore, because the pre-surface-layer-processed lumber NW11 contains knots K and the knots K are hard, the thickness between the hard knots K and the design surface D can be significantly compressed. This makes it possible to increase the compression rate on the design surface D side, thereby increasing the surface hardness. At this time, even if there are knots K in the surface pre-processed wood NW11, by pressing and deforming the soft parts of the lower layer pre-processed wood NW12 that do not have knots K, the knots K are less likely to be subjected to stress, making it less likely that the knots K will crack or otherwise break.

[0174] In particular, in the third embodiment, the pre-surface-layer-processed lumber NW11 having knots K and the pre-lower-layer-processed lumber NW12 without knots K are laminated perpendicular to the longitudinal direction of the grain with their grains aligned, and the presence of knots K in the pre-surface-layer-processed lumber NW11 increases the compression rate of the thickness between the hard knots K and the design surface D, thereby increasing the surface hardness. Furthermore, even if the pre-surface-layer-processed lumber NW11 has knots K, the knots K of the pre-surface-layer-processed lumber NW11 are likely to press and deform the softer parts without knots of the pre-lower-layer-processed lumber NW12, and the knots K are unlikely to be subjected to load, thereby preventing the knots K from cracking due to heating and compression. That is, the laminated plastically processed timber LPW3 of the third embodiment is made by laminating and bonding the surface-layer plastically processed timber PW11 and the lower-layer plastically processed timber PW12 that constitute it with their grains aligned in the longitudinal direction, and therefore the presence of hard knots K in the surface-layer plastically processed timber PW11 increases the compressibility of the thickness between the hard knots K of the surface-layer plastically processed timber PW11 and the design surface D, thereby increasing the surface hardness. At this time, the knots K of the surface-layer plastically processed timber PW11 strongly press and deform the soft parts without knots K of the lower-layer plastically processed timber PW12, and therefore the surface hardness can be increased without causing cracks at the knots K.

[0175] As described above, preferably, the unprocessed wood NW11 having knots K has its surface side facing the design surface D, and the unprocessed wood NW12 has its back side facing the design surface D, and the unprocessed wood NW12 has its back side facing the design surface D, and the unprocessed wood NW12 has its back side facing the design surface D, and the unprocessed wood NW12 has its back side facing the design surface D, and the unprocessed wood NW12 has its back side facing the design surface D, and the unprocessed wood NW12 has its back side facing the design surface D, and the unprocessed wood NW12 has its back side facing the design surface D, and the unprocessed wood NW12 has its back side facing the design surface D. The laminated pre-processed lumber PNW3 is made by stacking pre-processed lumber NW11 with knots K and pre-processed lumber NW12 without knots K, with the grain side facing away from the design side. By heating and compressing the laminated pre-processed lumber PNW3 in a direction perpendicular to the length of the grain, the resistance generated at the boundary between the pre-processed lumber NW11 and the pre-processed lumber NW12 increases, allowing for greater compression of the design surface D side of the pre-processed lumber NW11 closer to the movable press platen 10A. This increases the compression rate of the design surface D side of the laminated plastically processed lumber LPW3, thereby increasing the surface hardness. Furthermore, the variation in surface hardness can be reduced, resulting in more stable surface hardness characteristics.

[0176] That is, the design surface D side of the surface plastically processed wood PW11 that constitutes the laminated plastically processed lumber LPW3 is the plain grain or straight grain side of the wood surface, and the opposite side, the bonding surface with the lower layer plastically processed wood PW12, is the plain grain or straight grain side of the wood back, and the bonding surface with the surface plastically processed wood PW11 of the lower layer plastically processed wood PW12 that constitutes the laminated plastically processed lumber LPW3 is the plain grain or straight grain side of the wood back, and the opposite side, the anti-design surface, is the plain grain or straight grain side of the wood surface. In this case, it is possible to increase the compression ratio of the design surface D side of the laminated plastically processed lumber LPW3 and increase the surface hardness. Furthermore, variation in surface hardness can be reduced, and the surface hardness characteristics can be more stabilized.

[0177] Furthermore, the plain grain or straight grain side of the surface of the surface plastically processed timber PW11 is the press surface that the movable press platen 10A abuts against, and the plain grain or straight grain side of the surface of the lower layer plastically processed timber PW12 is the press surface that the fixed press platen 10B abuts against, and the wood is compressed in a compression direction that causes little distortion, internal resistance, or stress due to compression.In addition, the plain grain or straight grain side of the surface of the wood is located on the front and back surfaces of the laminated plastically processed timber LPW3, and the anisotropy of shrinkage is balanced.Therefore, even if expansion and contraction forces occur due to changes in ambient environmental conditions such as humidity, moisture, and dryness after compaction processing, distortion is unlikely to occur, and the dimensional and shape stability is high.

[0178] In addition, in the third embodiment, it is preferable that the maximum value θ of the intersection angle (annual ring angle) θ2 on the acute side formed by the annual ring line GR2 appearing on the end grain surface of the lower layer plastically processed wood PW12 without knots K and the adhesive boundary line BL of the surface layer plastically processed wood PW11 and the lower layer plastically processed wood PW12. max2 The maximum value θ1 of the acute angle between the annual ring line GR1 and the adhesive boundary line BL on the end grain surface of the surface plastically processed wood PW11 with knot K is max1 is larger than (θ max2 >θ max1 ). In other words, the surface-processed wood PW11 with knots K has the maximum value θ1 of the acute angle (annual ring angle) θ1 formed by the annual ring line GR1 appearing on the butt end surface and the adhesive boundary line BL of the surface-processed wood PW11 and the lower-processed wood PW12. max1 The maximum value θ2 of the acute angle between the annual ring line GR2 and the adhesive boundary line BL on the butt end surface of the lower layer plastically processed wood PW11 without knots K is max2 It is smaller than

[0179] The maximum value of the annual ring angle θ2 in the lower layer plastically processed wood PW12 without knots K is max2 The maximum value of the annual ring angle θ1 in the surface plastically processed wood PW11 with knot K is max1In the laminated plastically processed timber LPW2, which is composed of a surface-layer plastically processed timber PW11 and a lower-layer plastically processed timber PW12 larger than the above, the lower-layer plastically processed timber PW12 is resistant to compression (has high compressive strength), so the design surface D side of the surface-layer plastically processed timber PW11 is strongly compressed. Therefore, the compression ratio of the design surface D side of the laminated plastically processed timber LPW3 can be further increased, and the surface hardness can be further increased. In addition, the variation in surface hardness can be reduced, and the surface hardness characteristics can be stabilized.

[0180] Furthermore, the maximum value of the annual ring angle θ1 in the surface plastically processed wood PW11 with knot K is max1 However, if the angle is preferably in the range of 10° or more and 50° or less, more preferably 10° or more and 45° or less, the surface plastically processed wood PW11 is relatively easily compressed even if knots K are present, and therefore the area between the design surface D side of the surface plastically processed wood PW11 and the knots K can be significantly compressed, thereby further increasing the compression rate of the design surface D side of the laminated plastically processed wood LPW3 and further increasing the surface hardness. The knots K are prevented from being crushed, and even if the knots K are exposed on the design surface D, the aesthetic appearance of the knots K can be improved.

[0181] In addition, the maximum value of the annual ring angle θ2 in the lower layer plastically processed wood PW12 without knots K is max2 However, if the angle is preferably within a range of 40° or more and less than 90°, and more preferably 45° or more and 85° or less, the lower layer plastically processed wood PW12 is more resistant to compression (has high compressive strength), and the design surface D side of the surface layer plastically processed wood PW11 is significantly compressed. Therefore, the compression ratio of the design surface D side of the laminated plastically processed wood LPW3 can be further increased, and the surface hardness can be further increased.

[0182] In addition, since the occupancy rate of knots K on the surface of the surface plastically processed wood PW11 containing knots K is preferably within the range of 0.5 to 20%, more preferably 1 to 15%, and even more preferably 3 to 15%, cracks, etc. around the knots K are less likely to occur, and the design surface D side of the surface plastically processed wood PW11 can be greatly compressed, further increasing the surface hardness, and further reducing the variation in surface hardness and making the surface hardness characteristics more stable.

[0183] In this way, by stacking pre-surface-processed wood NW11 containing knots K on top of pre-substrate-processed wood NW12 without knots K underneath and heating and compressing them perpendicular to the length direction of the wood grain, the knots K of the pre-surface-processed wood NW11 press and deform the knot-free areas of the pre-substrate-processed wood NW12, and the thickness between the design surface D and the knots K is highly compressed without causing the knots K to crack, so that the design surface D side of the pre-surface-processed wood NW11 is compressed more than the boundary line BL side with the pre-substrate-processed wood NW12.

[0184] In the laminated plastically processed lumber LPW3 of the third embodiment, the Brinell hardness (HB) of the design surface D side of the surface plastically processed lumber PW11 is 10 N / mm 2 More than 50N / mm 2 Within this range, cracks and fissures are unlikely to occur around the knots K, and even when used as flooring or the like, heel marks are unlikely to occur. Furthermore, even when used as a tabletop or the like, scratches caused by writing, cutters, or collisions with heavy objects such as desk legs are unlikely to occur, resulting in excellent maintenance of aesthetic appearance. More preferably, the Brinell hardness of the design surface D side of the wood NW11 before surface processing is 25 N / mm 2 More than 50N / mm 2 More preferably, 30 N / mm 2 More than 50N / mm 2 , particularly preferably 35 N / mm 2 More than 50N / mm 2 It is within the following range:

[0185] Furthermore, in the laminated plastically processed wood LPW3 of the third embodiment, the thickness of the surface layer plastically processed wood PW11 is preferably 0.3 to 1.0 times, and more preferably 0.5 to 0.6 times, the thickness of the lower layer plastically processed wood PW12 due to compaction. This thickness makes it difficult for cracks or fractures to occur due to compression, and high surface hardness can be obtained. Furthermore, the variation in surface hardness can be reduced, and the surface hardness characteristics can be more stabilized.

[0186] The laminated plastically processed wood LPW3 of this third embodiment has an overall thickness of preferably 10 mm to 40 mm, more preferably 10 mm to 35 mm, and even more preferably 10 mm to 30 mm, the thickness of the surface plastically processed wood PW11 is preferably 3 mm to 20 mm, more preferably 4 mm to 15 mm, and even more preferably 4 mm to 12 mm, and the thickness of the lower layer plastically processed wood PW12 is preferably 5 mm to 25 mm, more preferably 5 mm to 20 mm, and even more preferably 6 mm to 20 mm.Within these ranges, high surface hardness is ensured, but the thin overall thickness makes it lightweight.

[0187] Furthermore, the laminated plastically processed wood LPW3 of this third embodiment has a compression ratio of preferably 30% to 70%, more preferably 35% to 70%, relative to the air-dry specific gravity of the wood species of the original unprocessed wood NW, the surface plastically processed wood PW11 has a compression ratio of preferably 50% to 75%, more preferably 55% to 75%, relative to the air-dry specific gravity of the wood species of the original unprocessed wood NW, and the lower layer plastically processed wood PW12 has a compression ratio of preferably 15% to 55%, more preferably 20 to 50%, relative to the air-dry specific gravity of the wood species of the original unprocessed wood NW. Within these compression ratio ranges, lightweight and high surface hardness can be achieved at the same time.

[0188] In addition, the air-dry specific gravity of the laminated plastically processed lumber LPW3 of the third embodiment is preferably 1.2 to 2.5 times, more preferably 1.5 to 2.0 times, the air-dry specific gravity of the original unlaminated lumber NW. If the specific gravity is within this range, cracks and fractures due to compression are unlikely to occur, and both strength and lightness can be achieved.

[0189] In terms of the compression ratio of the thickness of the unprocessed wood NW11, 12, the laminated plastically processed wood LPW1 of the first embodiment preferably has a compression ratio of 30 to 75%, more preferably 35 to 75%, relative to the thickness of the laminated unprocessed wood LNW1, the surface layer plastically processed wood PW11 has a compression ratio of 50 to 75%, more preferably 55 to 75%, relative to the thickness of the original surface layer unprocessed wood NW11, and the lower layer plastically processed wood PW12 has a compression ratio of 15 to 55%, more preferably 20 to 50%, relative to the thickness of the original lower layer unprocessed wood NW12. Within these compression ratio ranges, lightweight and high surface hardness can be achieved at the same time.

[0190] In this way, in this embodiment 3, a lower layer pre-processed wood NW12 without knots K is layered underneath a surface layer pre-processed wood NW11 containing knots K via an adhesive to form a laminated pre-processed wood LNW3, and this laminated pre-processed wood LNW3 is then compacted to form laminated plastically processed wood LPW3.By taking advantage of the fact that resistance occurs at the boundary between the surface layer pre-processed wood NW11 and the lower layer pre-processed wood NW12 due to the different types of wood, it is made easier to compress the design surface D side of the surface layer pre-processed wood NW11 closer to the movable press platen 10A, and further, by taking advantage of the hardness of the knots K in the surface layer pre-processed wood NW11 and increasing the compression rate of the thickness between the hard knots K and the design surface D side, the surface hardness of the laminated plastically processed wood LPW3 is increased. Furthermore, even if there are knots K in the pre-surface processing wood NW11, the knots K in the pre-surface processing wood NW11 press against and deform soft parts of the pre-underlayer processing wood NW12 that do not have knots K, making it difficult for load to be applied to the knots K, and therefore the knots K are unlikely to crack due to heating and compression.

[0191] As explained above, the laminated plastically processed wood LPW3 of the third embodiment is a laminated plastically processed wood PLW3 in which two pieces of wood, namely, surface plastically processed wood PW11 and lower layer plastically processed wood PW12, are laminated and glued together perpendicular to the longitudinal direction of the wood grain, and which has been plastically processed by heating and compressing them perpendicular to the longitudinal direction of the wood grain and then fixing them, wherein the surface plastically processed wood PW11 which forms the design surface D has knots K, and the lower layer plastically processed wood PW12 which is glued to the surface plastically processed wood PW11 is pressed and deformed by the knots K of the surface plastically processed wood PW11 due to the heating and compression, so that the design surface D side of the surface plastically processed wood PW11 is more compressed than the boundary side with the lower layer plastically processed wood PW12 (the side of the adhesive boundary line BL).

[0192] The laminated plastically processed lumber LPW3 according to the third embodiment is made by stacking two pieces of wood, namely, a surface pre-processed lumber NW11 having knots K and a lower pre-processed lumber NW12 without knots K, and then heat-compressing and compressing them in a direction perpendicular to the length direction of the wood grain. That is, the laminated pre-processed lumber LNW3, in which the surface pre-processed lumber NW11 and the lower pre-processed lumber NW12 are stacked, is plastically processed (densified). When the laminated pre-processed lumber LNW3 is heat-compressed in a direction perpendicular to the length direction of the wood grain, Resistance occurs at the boundary between the surface pre-processed wood NW11 and the lower pre-processed wood NW12, which are connected together, increasing the compression rate on the design surface D side, and the knots K of the surface plastically processed wood PW11 press and deform the lower plastically processed wood PW12 during heated compression, resulting in high compression of the thickness between the hard knots K of the surface plastically processed wood PW11 and the design surface D without causing cracks in the knots K, resulting in the design surface D side of the surface plastically processed wood PW11 being compressed more highly than the boundary side with the lower plastically processed wood PW12.

[0193] Thus, according to the laminated plastically processed wood LPW3 of the above-mentioned embodiment 3, due to the laminated structure of the surface plastically processed wood PW11 and the lower layer plastically processed wood PW12, and because the hard knots K of the lower layer plastically processed wood PW12 are less likely to press and deform the surface plastically processed wood PW11, thereby placing a load on the knots K, the compression rate of the thickness between the hard knots K of the surface plastically processed wood PW11 and the design surface D can be increased without causing cracks in the knots K, and the surface hardness on the design surface D side can be increased.

[0194] In addition, deformation due to pressure from the knot K means that, when viewed from the end surface of the laminated plastically processed timber LPW3, the adhesive boundary line BL between the surface plastically processed timber PW11 and the lower layer plastically processed timber PW12 is bent, and when viewed from the adhesive surfaces (opposing surfaces) of the pre-surface processed timber NW11 and the lower layer plastically processed timber PW12, the knot K is convex on the adhesive surface of the surface plastically processed timber PW11, and the part of the surface plastically processed timber PW11 that has received the knot K is deformed concavely on the adhesive surface of the lower layer plastically processed timber PW12.

[0195] In addition, in the laminated plastically processed wood LPW3 of the above-mentioned embodiment 3, the surface plastically processed wood PW11 and the lower layer plastically processed wood PW12 are laminated and glued together with the longitudinal direction of the wood grain aligned with each other, so that the lower layer plastically processed wood PW12 is significantly compressed and deformed by the knots K of the surface plastically processed wood PW11, preventing cracking of the knots K, while allowing for greater compression between the hard knots K of the surface plastically processed wood PW11 and the design surface D, thereby increasing the compression rate on the design surface D side and further increasing the surface hardness, thereby reducing variation in surface hardness and stabilizing the surface hardness characteristics.

[0196] In the laminated plastically processed lumber LPW3 according to the third embodiment, when the surface layer plastically processed lumber PW11 and the lower layer plastically processed lumber PW12 are laminated and bonded together with the plain grain or longitudinal grain surfaces of the backside of the wood facing each other, the anisotropy of the shrinkage rate of the lumber is balanced. Therefore, even if expansion and contraction forces occur due to changes in the surrounding annular conditions, distortion, knots, cracks, etc. are unlikely to occur, and the dimensional and shape stability is high. Furthermore, when heated and compressed perpendicular to the length direction of the wood grain, higher resistance (compressive stress) occurs at the boundary between the laminated lumber pieces, which increases the compression rate on the design surface D. This improves surface hardness, reduces surface hardness variation, and stabilizes surface hardness characteristics.

[0197] That is, in the laminated plastically processed wood LPW3 according to the third embodiment, the design surface D of the surface layer plastically processed wood PW11 is a plain grain surface or a straight grain surface on the front side of the wood, and the opposite surface, which faces the lower layer plastically processed wood PW12, is a plain grain surface or a straight grain surface on the back side of the wood, and the surface of the lower layer plastically processed wood PW12 that faces the surface layer plastically processed wood PW11 is a plain grain surface or a straight grain surface on the back side of the wood. Because the design surface D is the flat grain or straight grain surface on the front side of the wood, it is easily compressed. Furthermore, because the surface plastically processed wood PW11 and the lower layer plastically processed wood PW12 are laminated with the flat grain or straight grain surfaces on the back side of the wood facing each other, the resistance (internal stress) at the boundary between the pieces of wood (bonding boundary line BL) is high when heated and compressed perpendicular to the length of the wood grain, which allows for greater compression of the design surface D side of the surface plastically processed wood PW11. This makes it possible to improve the surface hardness on the design surface D side, reduce variation in surface hardness, and make the surface hardness characteristics more stable.

[0198] The laminated plastically processed wood LPW3 according to the third embodiment has a Brinell hardness of 10 N / mm 2 More than 50N / mm 2 Less than or equal to 25N / mm 2 More than 50N / mm 2 More preferably, 30 N / mm 2 More than 50N / mm 2 , particularly preferably 35 N / mm 2 More than 50N / mm 2 This makes it difficult for heel marks to form when used as flooring or the like, and also makes it difficult for scratches caused by writing, cutters, or the like, or scratches caused by heavy objects such as desk legs to collide with it when used as a tabletop or the like, resulting in excellent maintenance of aesthetic appearance.

[0199] The laminated plastically processed timber LPW3 according to the third embodiment preferably has a maximum value θ of the acute angle θ2 formed by the annual ring line GR2 appearing on the end grain surface of the lower-layer plastically processed timber PW12 without knots K and the adhesive boundary line BL of the surface-layer plastically processed timber PW11 and the lower-layer plastically processed timber PW12. max2The maximum value θ1 of the acute angle between the annual ring line GR1 and the adhesive boundary line BL on the end grain surface of the surface plastically processed wood PW11 with knot K is max1 It is larger than Therefore, since the lower layer plastically processed wood PW12 is difficult to compress (has high compressive strength), the design surface D side of the surface layer plastically processed wood PW11 is strongly compressed. As a result, the compression ratio of the design surface D side of the laminated plastically processed wood LPW3 can be further increased, and the surface hardness can be further increased. In addition, the variation in surface hardness can be reduced, and the surface hardness characteristics can be stabilized.

[0200] The laminated plastically processed timber LPW3 according to the third embodiment has a maximum value θ of the acute angle θ1 formed by the annual ring line GR1 appearing on the end grain surface of the surface-layer plastically processed timber PW11 having knots K and the adhesive boundary line BL between the surface-layer plastically processed timber PW11 and the lower-layer plastically processed timber PW12. max1 is preferably 10° or more and 50° or less, more preferably 10° or more and 45° or less, so that the surface plastically processed lumber PW11 is relatively easily compressed even if knots K are present, and therefore the area between the design surface D side of the surface plastically processed lumber PW11 and the knots K can be greatly compressed, thereby further increasing the compression rate of the design surface D side of the laminated plastically processed lumber LPW3 and further increasing the surface hardness. In addition, the knots K are prevented from being crushed, and even if the knots K are exposed on the design surface D, the aesthetic appearance of the knots K can be improved.

[0201] Furthermore, the laminated plastically processed timber LPW3 according to the third embodiment has a maximum value θ of the annual ring angle θ2 in the lower layer plastically processed timber PW12 without knots K. max2 However, if the angle is preferably within a range of 40° or more and less than 90°, and more preferably 45° or more and 85° or less, the lower layer plastically processed wood PW12 is more resistant to compression (has high compressive strength), and the design surface D side of the surface layer plastically processed wood PW11 is significantly compressed. Therefore, the compression ratio of the design surface D side of the laminated plastically processed wood LPW3 can be further increased, and the surface hardness can be further increased.

[0202] Furthermore, in the laminated plastically processed wood LPW3 of the above-mentioned embodiment 3, the occupancy rate of knots K on the surface of the surface plastically processed wood PW11 having knots K is preferably within the range of 0.5 to 20%, more preferably 1 to 15%, and even more preferably 3 to 15%, thereby increasing the surface hardness while maintaining strength that is less susceptible to cracks, fissures, etc.

[0203] [Embodiment 4] Next, a laminated plastically processed wooden piece LPW4 according to a fourth embodiment of the present invention will be described with reference to FIG. The laminated plastically processed lumber LPW4 of this embodiment 4 is made by stacking three or more pieces (three pieces) of unprocessed lumber NW11, NW12, NW13, ..., NWn perpendicular to the length direction of the grain using adhesive, and plastically processing (compacting) them by heating, compressing and fixing them perpendicular to the length direction of the grain. In this fourth embodiment, cedar or cypress wood is also used for the three or more pieces of raw lumber NW11, NW12, NW13, ..., NWn. That is, the plastically processed lumber PW11, PW12, PW13, ..., PWn constituting the laminated plastically processed lumber LPW4 are made of cedar or cypress wood.

[0204] In the laminated plastically processed timber LPW4 of this embodiment 4, a surface layer pre-processed timber NW11 having one or more knots K on the surface layer facing the design surface D is used, and a lower layer pre-processed timber NW12 without knots K is layered directly below the surface layer pre-processed timber NW1 having knots K. Furthermore, one or more other pieces of pre-processed timber NW13, ..., NWn are layered below the lower layer pre-processed timber NW12. The surface layer pre-processed timber NW11 without knots K, the lower layer pre-processed timber NW12 with knots K, and one or more other pieces of pre-processed timber NW13, ..., NWn are layered in the thickness direction, which is perpendicular to the length direction of the wood grain, and are compacted by heat compression treatment and compression fixation treatment perpendicular to the length direction of the wood grain. The laminated plastically processed timber LPW4 consists of surface layer plastically processed timber PW11 with knots K, lower layer plastically processed timber PW12 without knots K, and one or more other pieces of plastically processed timber PW13, ..., PWn, which are layered and glued together.

[0205] In Figure 7, the laminated plastically processed wood LPW4 of this embodiment 4 is described as an example in which another piece of pre-processed wood NW13 is placed under the lower layer of pre-processed wood NW12, and the three pieces of pre-processed wood NW11, NW12, and NW13 are stacked perpendicular to the length direction of the wood grain using adhesive, and plastically processed by heating, compressing, and fixing the pieces perpendicular to the length direction of the wood grain. One or more pieces of unprocessed wood NW13,...,NWn that are stacked under the lower layer unprocessed wood NW12, i.e., one or more pieces of plastically processed wood PW13,...,PWn that are stacked under the lower layer plastically processed wood PW12, may or may not have knots K.

[0206] In the fourth embodiment as well, the surface layer unprocessed timber NW11 having knots K and the lower layer unprocessed timber NW12 without knots K are stacked perpendicular to the length direction of the wood grain with the length direction of the wood grain aligned. Furthermore, one or more other pieces of unprocessed timber NW13, ..., NWn overlapping below the lower layer unprocessed timber NW12 are also stacked perpendicular to the length direction of the wood grain with the length direction of the wood grain aligned with the length direction of the surface layer unprocessed timber NW11 and the lower layer unprocessed timber NW12. That is, the laminated plastically processed timber LPW4 of this embodiment 4 is made up of surface layer plastically processed timber PW11, lower layer plastically processed timber PW12, and one or more other pieces of plastically processed timber PW13, ..., PWn, which are stacked and glued together with their grains aligned in the longitudinal direction.

[0207] In the laminated plastically processed lumber LPW4 of this fourth embodiment, lumber having knots K is used for the surface layer pre-processed lumber NW11 that serves as its raw material, and lumber without knots K is used for the lower layer pre-processed lumber NW12, but preferably, flat grain lumber or straight grain lumber is used for the surface layer pre-processed lumber NW11 having knots K and the lower layer pre-processed lumber NW12 without knots K. Furthermore, flat grain lumber or straight grain lumber is preferably used for another one or more pieces of pre-processed lumber NW13,...,NWn that overlap below the lower layer pre-processed lumber NW12. That is, the surface layer plastically processed timber PW11 and the lower layer unprocessed timber PW12 constituting the laminated plastically processed timber LPW4 of this embodiment 4 are preferably flat grain timber or straight grain timber. Another one or more pieces of plastically processed timber PW13, ..., PWn overlapping the lower layer plastically processed timber PW12 are also preferably flat grain timber or straight grain timber.

[0208] Also, in this fourth embodiment, preferably, as shown in FIG. 7, the surface pre-processed timber NW11 having knots K has the flat grain or longitudinal side of its front side facing the design surface D, and the flat grain or longitudinal side of the back side of the wood on the opposite side facing the lower layer pre-processed timber NW12 without knots K, and the flat grain or longitudinal side of the back side of the lower layer pre-processed timber NW12 without knots K faces the surface pre-processed timber NW11, and the flat grain or longitudinal side of the front side of the wood on the opposite side faces the other pre-processed timber NW13 that is placed underneath, and the surface pre-processed timber NW11 having knots K and the lower layer pre-processed timber NW12 without knots K are stacked in their thickness direction.

[0209] Regarding another piece of unprocessed wood NW13 that is stacked under the lower layer unprocessed wood NW12, the side facing the lower layer unprocessed wood NW12 may be the plain grain or straight grain side of the front side of the wood, or the plain grain or straight grain side of the back side of the wood. When laminated plastically processed wood LPW4 is composed of surface layer plastically processed wood PW11, lower layer plastically processed wood PW12, and another piece of plastically processed wood PW13 stacked underneath, that is, when three pieces of pre-processed wood NW11, NW12, and NW13, namely surface layer pre-processed wood NW11, lower layer pre-processed wood NW12, and another piece of pre-processed wood NW13 stacked underneath the lower layer pre-processed wood NW12, are compressed to form laminated plastically processed wood LPW4, it is preferable that, as shown in Figure 7, the flat grain or longitudinal grain side of the back of the other piece of pre-processed wood NW13 stacked underneath the lower layer pre-processed wood NW12 be the side facing (adhering side) to the lower layer pre-processed wood NW12, and the flat grain or longitudinal grain side of the front of the wood be the opposite design side. If the counter-design surface of another piece of unprocessed wood NW13, which is opposite the design surface D of the surface layer unprocessed wood NW11, is the plain grain or longitudinal grain side of the wood surface, the press surface that the fixed press platen 10B abuts will be the plain grain or longitudinal grain side of the wood surface, and the wood will be compressed in a compression direction with less distortion, internal resistance, and stress due to compression. Therefore, the unprocessed wood NW13, which is layered under the lower layer unprocessed wood NW12 and forms the counter-design surface, will be more likely to compress, and even if it has knots K, it will be less likely to break or crack during compression. In other words, in the case of stacking three pieces of wood, it is preferable that the side of another piece of pre-processed wood NW13 that is placed underneath the lower layer pre-processed wood NW12 be the flat grain or straight grain side on the back side of the wood, and the flat grain or straight grain side on the opposite side be the press surface.This makes it easier for the other piece of pre-processed wood NW13, which is on the side opposite the design surface D of the surface layer pre-processed wood NW11, to be compressed, making it less likely to apply load to the knots K of the lower layer pre-processed wood NW12 and preventing the knots K from cracking.

[0210] If there is an odd number of sheets of plastically processed wood PW13,...,PWn overlapping the lower layer pre-plasticized wood PW12, i.e., if the entire laminated plastically processed wood LPW4 is made up of an odd number of sheets, it is preferable that the counter-design surface of the back layer of plastically processed wood PW13,...,PWn opposite the surface pre-processed wood NW11 be the flat grain or straight grain side of the wood surface. As a result, since the plastically processed wood PW13,...,PWn forming the counter-design surface is easily compressed, even if it contains knots K, it is less likely to break or crack during compression. However, when carrying out the present invention, the unprocessed wood NW13 that is overlapped under the lower layer unprocessed wood NW12 and forms the opposite design surface may have the flat grain or longitudinal side on the front side of the wood as the surface facing (bonding surface) with the lower layer unprocessed wood NW12, and the flat grain or longitudinal side on the back side of the wood as the opposite design surface. In other words, the opposite design surface of the plastically processed wood PW13 opposite to the design surface D of the surface layer unprocessed wood NW11 may be the flat grain or longitudinal side on the back side of the wood.

[0211] In the fourth embodiment, the surface layer unprocessed lumber NW11 having knots K is used as the surface layer (upper layer), the lower layer unprocessed lumber NW12 without knots K is stacked under the surface layer unprocessed lumber NW11, and one or more other unprocessed lumber NW13, ..., NWn are stacked under that. At this time, adhesive is applied between the lumber pieces to form a laminated unprocessed lumber LNW4, and three or more unprocessed lumber pieces NW11, NW12, NW13, ..., NWn are stacked. The laminated pre-processed wood LNW4 consisting of the above is heated and compressed in the thickness direction, i.e., perpendicular to the length direction of the grain of the pre-processed wood NW11, NW12, NW13, ..., NWn, and the compression is fixed to form a laminated plastically processed wood LPW4 consisting of surface layer plastically processed wood PW11, lower layer plastically processed wood PW12, and one or more other pieces of plastically processed wood PW13, ..., PWn, which are stacked and bonded together.

[0212] Here, in the fourth embodiment as well, when the pre-surface-layer-processed lumber NW11 containing knots K is stacked as the surface layer (upper layer) and the pre-lower-layer-processed lumber NW12 without knots K is stacked as the lower layer, and they are heated and compressed perpendicular to the length direction of the wood grain, resistance (compressive stress) occurs at the boundary between the pre-surface-layer-processed lumber NW11 and the pre-lower-layer-processed lumber NW12 due to the different wood structures (the wood structures are discontinuous), and therefore the design surface D side of the pre-surface-layer-processed lumber NW11 closer to the movable press platen 10A can be significantly compressed. Furthermore, because the pre-surface-layer-processed lumber NW11 contains knots K and the knots K are hard, the thickness between the hard knots K and the design surface D can be significantly compressed. Therefore, it is possible to increase the compression rate on the design surface D side, and the surface hardness can be increased. At this time, even if there are knots K in the surface pre-processed wood NW11, by pressing and deforming the soft parts of the lower layer pre-processed wood NW12 that do not have knots K, the knots K are less likely to be subjected to load and cracks or the like are less likely to occur in the knots K.

[0213] Also in the fourth embodiment, the pre-surface-layer-processed lumber NW11 having knots K and the pre-lower-layer-processed lumber NW12 without knots K are laminated perpendicular to the longitudinal direction of the grain with their grains aligned, and the presence of knots K in the pre-surface-layer-processed lumber NW11 increases the compression rate of the thickness between the hard knots K and the design surface D, thereby increasing the surface hardness. Even if the pre-surface-layer-processed lumber NW11 has knots K, the knots K of the pre-surface-layer-processed lumber NW11 are likely to press and deform the softer parts without knots of the pre-lower-layer-processed lumber NW12, and the knots K are unlikely to be subjected to load, thereby preventing the knots K from cracking due to heat compression. That is, the laminated plastically processed timber LPW4 of the fourth embodiment is made by laminating and bonding the surface-layer plastically processed timber PW11 and the lower-layer plastically processed timber PW12 that constitute it with their grains aligned in the longitudinal direction, and therefore the presence of hard knots K in the surface-layer plastically processed timber PW11 increases the compressibility of the thickness between the hard knots K of the surface-layer plastically processed timber PW11 and the design surface D, thereby increasing the surface hardness. At this time, the knots K of the surface-layer plastically processed timber PW11 strongly press against and deform the soft parts of the lower-layer plastically processed timber PW12 that are free of knots K, and therefore the surface hardness can be increased without causing cracks at the knots K.

[0214] In addition, when the design surface D side of the surface plastically processed wood PW11 that constitutes the laminated plastically processed wood LPW4 is the plain grain or straight grain side of the wood surface, and the opposite side, the bonding surface side opposite to the lower layer plastically processed wood PW12, is the plain grain or straight grain side of the wood back side, and the bonding surface side opposite to the surface plastically processed wood PW11 of the lower layer plastically processed wood PW12 is the plain grain or straight grain side of the wood back side, and the plain grain or straight grain side of the opposite side is the bonding surface side opposite to another piece of plastically processed wood PW13 that is overlapping it, the resistance (compressive stress) that occurs at the boundary between the surface plastically processed wood PW11 and the lower layer plastically processed wood PW12 is higher, making it possible to increase the compression rate of the design surface D side of the laminated plastically processed wood LPW4 and increase the surface hardness. Furthermore, the variation in surface hardness can be reduced, and the surface hardness characteristics can be more stabilized.

[0215] Furthermore, when the plain grain or straight grain side of the surface of the surface-layered plastically processed lumber PW11 is the press surface that the movable press platen 10A abuts against, and when the plain grain or straight grain side of the surface of another piece of plastically processed lumber PW13 is the press surface that the fixed press platen 10B abuts against, the lumber is compressed in a compression direction that results in less distortion, internal resistance, and stress due to compression.In addition, since the plain grain or straight grain side of the surface of the lumber is located on the front and back surfaces of the laminated plastically processed lumber LPW4, the anisotropy of shrinkage is balanced, even if expansion and contraction forces occur due to changes in ambient environmental conditions such as humidity, moisture, and dryness after compaction processing, distortion is less likely to occur, and the dimensional and shape stability is high. In addition, if the opposite design surface of the plastically processed wood PW13 on the opposite side to the design surface D of the surface plastically processed wood PW11 is the plain grain or straight grain side of the wood surface, the plastically processed wood PW13 forming the opposite design surface is easily compressed, so even if there is a knot K, it is less likely to crack or break during compression.

[0216] In addition, in the fourth embodiment, it is preferable that the maximum value θ of the intersection angle (annual ring angle) θ2 on the acute side formed by the annual ring line GR2 appearing on the end grain surface of the lower layer plastically processed wood PW12 without knots K and the adhesive boundary line BL of the surface layer plastically processed wood PW11 and the lower layer plastically processed wood PW12.max2 The maximum value θ1 of the acute angle between the annual ring line GR1 and the adhesive boundary line BL on the end grain surface of the surface plastically processed wood PW11 with knot K is max1 is larger than (θ max2 >θ max1 ). In other words, the surface-processed wood PW11 with knots K has the maximum value θ1 of the acute angle (annual ring angle) θ1 formed by the annual ring line GR1 appearing on the butt end surface and the adhesive boundary line BL of the surface-processed wood PW11 and the lower-processed wood PW12. max1 The maximum value θ2 of the acute angle between the annual ring line GR2 and the adhesive boundary line BL on the butt end surface of the lower layer plastically processed wood PW11 without knots K is max2 It is smaller than

[0217] The maximum value of the annual ring angle θ2 in the lower layer plastically processed wood PW12 without knots K is max2 The maximum value of the annual ring angle θ1 in the surface plastically processed wood PW11 with knot K is max1 In the laminated plastically processed timber LPW4, which is composed of a surface-layer plastically processed timber PW11 and a lower-layer plastically processed timber PW12 larger than the above, the lower-layer plastically processed timber PW12 is resistant to compression (has high compressive strength), so the design surface D side of the surface-layer plastically processed timber PW11 is strongly compressed. Therefore, the compression ratio of the design surface D side of the laminated plastically processed timber LPW5 can be further increased, and the surface hardness can be further increased. In addition, the variation in surface hardness can be reduced, and the surface hardness characteristics can be stabilized.

[0218] Furthermore, the maximum value of the annual ring angle θ1 in the surface plastically processed wood PW11 with knot K is max1 However, if the angle is preferably in the range of 10° or more and 50° or less, more preferably 10° or more and 45° or less, the surface plastically processed wood PW11 is relatively easily compressed even if knots K are present, and therefore the area between the design surface D side of the surface plastically processed wood PW11 and the knots K can be significantly compressed, thereby further increasing the compression rate of the design surface D side of the laminated plastically processed wood LPW4 and further increasing the surface hardness. The knots K are prevented from being crushed, and even if the knots K are exposed on the design surface D, the aesthetic appearance of the knots K can be improved.

[0219] In addition, the maximum value of the annual ring angle θ2 in the lower layer plastically processed wood PW12 without knots K is max2 However, if the angle is preferably in the range of 40° or more and less than 90°, and more preferably 45° or more and 85° or less, the lower layer plastically processed wood PW12 is more resistant to compression (has high compressive strength), and the design surface D side of the surface layer plastically processed wood PW11 is significantly compressed. Therefore, the compression ratio of the design surface D side of the laminated plastically processed wood LPW4 can be further increased, and the surface hardness can be further increased.

[0220] In addition, in this embodiment 4, the occupancy rate of knots K on the surface of the surface plastically processed wood PW11 containing knots K is preferably within the range of 0.5 to 20%, more preferably 1 to 15%, and even more preferably 3 to 15%, which makes it less likely for cracks, fissures, etc. to occur around the knots K, and allows the design surface D side of the surface plastically processed wood PW11 to be greatly compressed, thereby further increasing the surface hardness, and further reducing the variation in surface hardness and making the surface hardness characteristics more stable.

[0221] In this fourth embodiment, too, a surface layer of pre-processed wood NW11 containing knots K is stacked on top of a lower layer of pre-processed wood NW12 without knots K, and then one or more pieces of pre-processed wood NW13, ..., NWn are stacked underneath that, and these pieces are heated and compressed perpendicular to the length direction of the wood grain.This causes the knots K of the surface layer of pre-processed wood NW12 to press and deform the knot-free parts of the lower layer of pre-processed wood NW12, and the thickness between the knots K of the surface layer of pre-processed wood NW12 and the design surface D is highly compressed without causing cracks in the knots K, so that the design surface D side of the surface layer of pre-processed wood NW11 is more compressed than the boundary line BL side with the lower layer of pre-processed wood NW12.

[0222] In the laminated plastically processed lumber LPW4 of the fourth embodiment, the Brinell hardness (HB) of the design surface D side of the surface plastically processed lumber PW11 is 10 N / mm 2 More than 50N / mm 2Within this range, cracks and fissures are unlikely to occur around the knots K, and even when used as flooring or the like, heel marks are unlikely to occur. Furthermore, even when used as a tabletop or the like, scratches caused by writing, cutters, or collisions with heavy objects such as desk legs are unlikely to occur, resulting in excellent maintenance of aesthetic appearance. More preferably, the Brinell hardness of the design surface D side of the wood NW11 before surface processing is 25 N / mm 2 More than 50N / mm 2 More preferably, 30 N / mm 2 More than 50N / mm 2 , particularly preferably 35 N / mm 2 More than 50N / mm 2 It is within the following range:

[0223] Furthermore, in the laminated plastically processed wood LPW4 of the fourth embodiment, the thickness of the surface layer plastically processed wood PW11 is preferably 0.3 to 1.0 times, and more preferably 0.4 to 0.6 times, the thickness of the lower layer plastically processed wood PW12 due to compaction. This thickness makes it difficult for cracks or fractures to occur due to compression, and high surface hardness can be obtained. Furthermore, the variation in surface hardness can be reduced, and the surface hardness characteristics can be more stabilized. At this time, the thickness of the plastically processed wood PW13 on the opposite design surface side is easily compressed by the fixed side press platen 10B, so it is preferably in the range of 0.4 to 1.0 times, more preferably 0.5 to 0.9 times, the thickness of the lower layer plastically processed wood PW12, and preferably in the range of 1.0 to 2.0 times, more preferably 1.2 to 1.8 times, the thickness of the surface layer plastically processed wood PW11.

[0224] For example, in Figure 7, the laminated plastically processed wood LPW4 of this embodiment 4 is preferably in the range of 10 mm or more and 40 mm or less, more preferably 10 mm or more and 35 mm or less, and even more preferably 10 mm or more and 30 mm or less, the thickness of the surface plastically processed wood PW11 is preferably in the range of 3 mm or more and 20 mm or less, more preferably 4 mm or more and 15 mm or less, and even more preferably 4 mm or more and 12 mm or less, the thickness of the lower layer plastically processed wood PW12 is preferably in the range of 5 mm or more and 25 mm or less, more preferably 5 mm or more and 20 mm or less, and even more preferably 6 mm or more and 20 mm or less, and the thickness of one piece of plastically processed wood PW13 that overlaps the lower layer plastically processed wood PW12 and forms the opposite design surface is preferably in the range of 4 mm or more and 20 mm or less, preferably 5 mm or more and 19 mm or less, and even more preferably 6 mm or more and 18 mm or less. Within this range, a high surface hardness is ensured, but the overall thickness is thin and lightweight.

[0225] Furthermore, in the laminated plastically processed wood LPW4 of this fourth embodiment, the compression ratio relative to the air-dry specific gravity of the wood species of the original unprocessed wood NW is preferably 30% to 70%, more preferably 35% to 70%, while the compression ratio relative to the air-dry specific gravity of the wood species of the original unprocessed wood NW of the surface plastically processed wood PW11 is preferably 50% to 75%, more preferably 55% to 75%, and the compression ratio relative to the air-dry specific gravity of the wood species of the original unprocessed wood NW of the lower layer plastically processed wood PW12 is preferably 15% to 55%, more preferably 20 to 50%. Within these compression ratio ranges, both light weight and high surface hardness can be achieved. At this time, the compression rate of the plastically processed wood PW13 forming the counter-design surface is preferably 20% to 60%, more preferably 25% to 50%, relative to the air-dry specific gravity of the original unprocessed wood NW13.

[0226] Additionally, the air-dry specific gravity of the laminated plastically processed lumber LPW4 of this fourth embodiment is preferably in the range of 1.2 to 2.5 times, more preferably 1.5 to 2.0 times, the air-dry specific gravity of the original unprocessed lumber NW. If it is within this range, cracks and fractures due to compression are unlikely to occur, and both strength and lightness can be achieved.

[0227] In terms of the compression ratio of the thickness of the pre-processed wood NW11, 12, 13, the laminated plastically processed wood LPW4 of this embodiment 4 has a compression ratio of preferably 30 to 75%, more preferably 35 to 75%, relative to the overall thickness of the laminated pre-processed wood LNW2; the surface plastically processed wood PW11 has a compression ratio of preferably 50% to 75%, more preferably 55% to 75%, relative to the thickness of the original surface pre-processed wood NW11; the lower layer plastically processed wood PW12 has a compression ratio of 15% to 55%, more preferably 20 to 50%, relative to the thickness of the original lower layer pre-processed wood NW12; and the other plastically processed wood PW13 has a compression ratio of preferably 20% to 55%, more preferably 25 to 50%, relative to the thickness of the original other pre-processed wood NW13. Within this range of compression ratio, both light weight and high surface hardness can be achieved.

[0228] Thus, in this embodiment 4, a lower layer pre-processed wood NW12 without knots K is layered underneath the surface layer pre-processed wood NW11 having knots K, via an adhesive, and one or more other pieces of pre-processed wood NW13, ..., NWn are layered underneath that to form a laminated pre-processed wood LNW4, and this laminated pre-processed wood LNW4 is then compacted to form laminated plastically processed wood LPW4.In this embodiment 4, too, the difference in wood between the surface layer pre-processed wood NW11 and the lower layer pre-processed wood NW12 makes it easier to compress the design surface D side of the surface layer pre-processed wood NW11 closer to the movable press platen 10A, and furthermore, by utilizing the hardness of the knots K in the surface layer pre-processed wood NW11 and increasing the compression rate of the thickness between the hard knots K and the design surface D side, the surface hardness of the laminated plastically processed wood LPW4 is increased. Furthermore, even if there are knots K in the pre-surface processing wood NW11, the knots K in the pre-surface processing wood NW11 press against and deform soft parts of the pre-underlayer processing wood NW12 that do not have knots K, making it difficult for load to be applied to the knots K, and therefore the knots K are unlikely to crack due to heating and compression.

[0229] As explained above, the laminated plastically processed wood LPW4 according to the fourth embodiment is a laminated plastically processed wood LPW4 in which three or more pieces of wood, namely, surface layer plastically processed wood PW11, lower layer plastically processed wood PW12, and other plastically processed wood PW13, ..., PWn, are laminated and glued together perpendicular to the longitudinal direction of the wood grain, and which has been plastically processed by heating and compressing them perpendicular to the longitudinal direction of the wood grain and then fixing them, wherein the surface layer plastically processed wood PW11, which forms the design surface D, has knots K, and the lower layer plastically processed wood PW12 glued to the surface layer plastically processed wood PW11 is pressed and deformed by the knots K of the surface layer plastically processed wood PW11 due to the heating and compression, so that the design surface D side of the surface layer plastically processed wood PW11 is more compressed than the boundary side with the lower layer plastically processed wood PW12 (the side of the adhesive boundary line BL).

[0230] According to the laminated plastically processed lumber LPW4 according to the fourth embodiment, three or more pieces of wood, namely, a surface layer pre-processed lumber NW11, a lower layer pre-processed lumber NW12, and other pre-processed lumber NW13, . . ., NWn, are laminated and heated and compressed in a direction perpendicular to the length direction of the wood grain, and are then compressed and fixed. In other words, the laminated pre-processed lumber LNW4, which is made by stacking a surface layer pre-processed lumber NW11, a lower layer pre-processed lumber NW12, and one or more other pre-processed lumber NW13, . . ., NWn, is plastically processed and is fixed in the length direction of the wood grain. When heated and compressed vertically, resistance occurs at the boundary between the stacked surface pre-processed wood NW11 and lower layer pre-processed wood NW12, which increases the compression rate on the design surface D side; and when heated and compressed, the knots K of the surface plastically processed wood PW11 press and deform the lower layer plastically processed wood PW12, and the thickness between the hard knots K of the surface plastically processed wood PW11 and the design surface D is highly compressed without causing cracks in the knots K, so that the design surface D side of the surface plastically processed wood PW11 is more compressed than the boundary side with the lower layer plastically processed wood PW12.

[0231] Thus, according to the laminated plastically processed wood LPW4 of the above-mentioned embodiment 4, due to the laminated structure of the surface layer plastically processed wood PW11, the lower layer plastically processed wood PW12, and the plastically processed wood PW, ..., PWn, and because the hard knots K of the lower layer plastically processed wood PW12 are less likely to press and deform the surface layer plastically processed wood PW11, thereby placing a load on the knots K, the compression rate of the thickness between the hard knots K of the surface layer plastically processed wood PW11 and the design surface D can be increased without causing cracks in the knots K, and the surface hardness on the design surface D side can be increased.

[0232] In addition, in the laminated plastically processed wood LPW4 of the above-mentioned embodiment 4, the surface plastically processed wood PW11 and the lower layer plastically processed wood PW12 are laminated and glued together with the longitudinal direction of the wood grain aligned with each other, so that the lower layer plastically processed wood PW12 is significantly compressed and deformed by the knots K of the surface plastically processed wood PW11, preventing cracking of the knots K, while allowing for greater compression between the hard knots K of the surface plastically processed wood PW11 and the design surface D, thereby further increasing the compression rate on the design surface D side and further increasing the surface hardness, thereby reducing variation in surface hardness and stabilizing the surface hardness characteristics.

[0233] In the laminated plastically processed lumber LPW4 according to the fourth embodiment, when the surface layer plastically processed lumber PW11 and the lower layer plastically processed lumber PW12 are laminated and bonded together with the plain grain or longitudinal grain surfaces of the backside of the wood facing each other, the anisotropy of the shrinkage rate of the lumber is balanced. Therefore, even if expansion and contraction forces occur due to changes in the surrounding annular conditions, distortion, knots, cracks, etc. are unlikely to occur, and the dimensional and shape stability is high. Furthermore, when heated and compressed perpendicular to the length direction of the wood grain, higher resistance (compressive stress) occurs at the boundary between the laminated lumber pieces, which increases the compression rate on the design surface D. This improves surface hardness, reduces surface hardness variation, and stabilizes surface hardness characteristics.

[0234] That is, in the laminated plastically processed timber LPW4 according to the fourth embodiment, the design surface D of the surface layer plastically processed timber PW11 is a plain grain surface or a straight grain surface on the front side of the wood, and the opposite surface, which faces the lower layer plastically processed timber PW12, is a plain grain surface or a straight grain surface on the back side of the wood, and the surface of the lower layer plastically processed timber PW12 which faces the surface layer plastically processed timber PW11 is a plain grain surface or a straight grain surface on the back side of the wood, Because the design surface D is the flat grain or straight grain surface on the front side of the wood, it is easily compressed. Furthermore, because the surface plastically processed wood PW11 and the lower layer plastically processed wood PW12 are laminated with the flat grain or straight grain surfaces on the back side of the wood facing each other, the resistance (internal stress) at the boundary between the pieces of wood (bonding boundary line BL) is high when heated and compressed perpendicular to the length of the wood grain, which allows for greater compression of the design surface D side of the surface plastically processed wood PW11. This makes it possible to improve the surface hardness on the design surface D side, reduce variation in surface hardness, and make the surface hardness characteristics more stable.

[0235] The laminated plastically processed wood LPW4 according to the fourth embodiment has a Brinell hardness of 10 N / mm 2 More than 50N / mm 2 Less than or equal to 25N / mm 2 More than 50N / mm 2 More preferably, 30 N / mm 2More than 50N / mm 2 , particularly preferably 35 N / mm 2 More than 50N / mm 2 This makes it difficult for heel marks to form when used as flooring or the like, and also makes it difficult for scratches caused by writing, cutters, or the like, or scratches caused by heavy objects such as desk legs to collide with it when used as a tabletop or the like, resulting in excellent maintenance of aesthetic appearance.

[0236] The laminated plastically processed timber LPW4 according to the fourth embodiment preferably has a maximum value θ of the acute angle θ2 formed by the annual ring line GR2 appearing on the end grain surface of the lower-layer plastically processed timber PW12 without knots K and the adhesive boundary line BL of the surface-layer plastically processed timber PW11 and the lower-layer plastically processed timber PW12. max2 The maximum value θ1 of the acute angle between the annual ring line GR1 and the adhesive boundary line BL on the end grain surface of the surface plastically processed wood PW11 with knot K is max1 It is larger than Therefore, since the lower layer plastically processed wood PW12 is difficult to compress (has high compressive strength), the design surface D side of the surface layer plastically processed wood PW11 is strongly compressed. As a result, the compression ratio of the design surface D side of the laminated plastically processed wood LPW4 can be further increased, and the surface hardness can be further increased. In addition, the variation in surface hardness can be reduced, and the surface hardness characteristics can be stabilized.

[0237] The laminated plastically processed timber LPW4 according to the fourth embodiment has a maximum value θ of the acute angle θ1 formed by the annual ring line GR1 appearing on the end grain surface of the surface-layer plastically processed timber PW11 having knots K and the adhesive boundary line BL between the surface-layer plastically processed timber PW11 and the lower-layer plastically processed timber PW12. max1 is preferably in the range of 10° or more and 50° or less, more preferably 10° or more and 45° or less, so that the surface plastically processed timber PW11 is relatively easily compressed even if knots K are present, and therefore the area between the design surface D side of the surface plastically processed timber PW11 and the knots K can be significantly compressed, thereby increasing the compression rate of the design surface D side of the laminated plastically processed timber LPW4 and further increasing the surface hardness. In addition, the knots K are prevented from being crushed, and even if the knots K are exposed on the design surface D, the aesthetic appearance of the knots K can be improved.

[0238] Furthermore, the laminated plastically processed timber LPW4 according to the fourth embodiment has a maximum value θ of the annual ring angle θ2 in the lower layer plastically processed timber PW12 without knots K. max2 However, if the angle is preferably in the range of 40° or more and less than 90°, and more preferably 45° or more and 85° or less, the lower layer plastically processed wood PW12 is more resistant to compression (has high compressive strength), and the design surface D side of the surface layer plastically processed wood PW11 is significantly compressed. Therefore, the compression ratio of the design surface D side of the laminated plastically processed wood LPW4 can be further increased, and the surface hardness can be further increased.

[0239] Furthermore, in the laminated plastically processed wood LPW4 of the above-mentioned embodiment 4, the occupancy rate of knots K on the surface of the surface plastically processed wood PW11 having knots K is preferably within the range of 0.5 to 20%, more preferably 1 to 15%, and even more preferably 3 to 15%, thereby increasing the surface hardness while maintaining strength that is less susceptible to cracks, fissures, etc.

[0240] [Embodiment 5] Next, a laminated plastically processed wooden piece LPW5 according to a fifth embodiment of the present invention will be described with reference to FIG. The laminated plastically processed lumber LPW5 of this embodiment 5 is made by stacking two pieces (two pieces) of unprocessed lumber NW11, NW12 perpendicular to the length direction of their grain using adhesive, and then plastically processing (compacting) them by heating, compressing, and fixing them perpendicular to the length direction of the grain. In this fifth embodiment, the two pieces of unprocessed wood NW1 and unprocessed wood NW2 are both made of cedar or cypress. That is, the surface layer plastically processed wood PW11 and the lower layer plastically processed wood PW12 that make up the laminated plastically processed wood LPW5 are made of cedar or cypress.

[0241] In detail, the laminated plastically processed timber LPW5 of this embodiment 5 uses pre-surface-processed timber NW11 having one or more knots K on the surface layer facing the design surface D, and under the pre-surface-processed timber NW1 having knots K, pre-processed lower layer timber NW12 (pre-backside-processed timber NW12) having one or more knots K is layered, and the pre-surface-processed timber NW11 and pre-processed lower layer timber NW12, both of which have knots K, are stacked in the thickness direction, which is perpendicular to the length direction of the wood grain, and then compacted by heat compression treatment and compression fixation treatment perpendicular to the length direction of the wood grain, and the laminated plastically processed timber LPW5 consists of surface-layer plastically processed timber PW11 having knots K and lower-layer plastically processed timber PW12 having knots K that are stacked and glued together.

[0242] In the laminated plastically processed lumber LPW5 of this fifth embodiment, wood having knots K is used for the surface layer pre-processing lumber NW11 that serves as the raw material, and wood having knots K is also used for the lower layer pre-processing lumber NW12, but preferably, flat grain lumber or straight grain lumber is used for the surface layer pre-processing lumber NW11 having knots K and the lower layer pre-processing lumber NW12 having knots K. In other words, the surface layer plastically processed lumber PW11 and the lower layer pre-processing lumber PW12 that constitute the laminated plastically processed lumber LPW5 are preferably flat grain lumber or straight grain lumber.

[0243] More preferably, as shown in FIG. 8, the pre-surface-processed lumber NW11 having knots K has the flat grain or longitudinal side of its front surface facing the design surface D, and the flat grain or longitudinal side of the back surface of the opposite side facing the lower-layer-processed lumber NW12 having knots K; and the pre-surface-processed lumber NW11 having knots K and the pre-substrate-processed lumber NW12 having knots K are stacked in their thickness direction, with the flat grain or longitudinal side of the back surface of the lower-layer-processed lumber NW12 having knots K facing the pre-surface-processed lumber NW11 and the flat grain or longitudinal side of the front surface of the opposite side facing the design surface D.

[0244] In this embodiment 5, the surface pre-processed wood NW11 and the lower layer pre-processed wood NW12, both of which have knots K, are stacked so that the knots K do not overlap each other in the thickness direction, and when heated and compressed, the knots K of the surface pre-processed wood NW11 and the knots K of the lower layer pre-processed wood NW12 collide with each other, causing stress to concentrate on the knots K, preventing cracks and fissures from occurring around the knots K. That is, in the laminated plastically processed timber LPW5 of this embodiment 5, the surface layer plastically processed timber PW11 and the lower layer plastically processed timber PW12, both of which have knots K, are laminated so that their knots K do not overlap in the thickness direction.

[0245] Furthermore, in this fifth embodiment, the surface layer unprocessed timber NW11 having knots K and the lower layer unprocessed timber NW12 having knots K are laminated in a direction perpendicular to the length direction of the wood grain with the length directions of the wood grain aligned. That is, the laminated plastically processed timber LPW5 of this fifth embodiment is formed by laminating and bonding the surface layer plastically processed timber PW11 and the lower layer plastically processed timber PW12 that constitute it with the length directions of the wood grain aligned.

[0246] In this embodiment 5, the surface layer pre-processed wood NW11 having knots K is used as the surface layer (upper layer), and the lower layer pre-processed wood NW12 having knots K is stacked underneath the surface layer pre-processed wood NW11 to form the lower layer (back layer).At this time, adhesive is applied between the two pieces of pre-processed wood NW11 and NW12, and the laminated pre-processed wood LNW5 is formed by stacking them together.The laminated pre-processed wood LNW5, which consists of two pieces of pre-processed wood NW11 and NW12, is heated and compressed in the thickness direction, i.e., perpendicular to the length direction of the grain of the pre-processed wood NW11 and NW12, and a compaction process (plastic processing) is performed to fix the compression, thereby forming laminated plastically processed wood LPW5 consisting of the surface layer plastically processed wood PW11 and the lower layer plastically processed wood PW12 that are stacked and bonded together.

[0247] Here, when the pre-surface-layer-processed lumber NW11 containing knots K is stacked as the surface layer (upper layer) and the pre-lower-layer-processed lumber NW12 containing knots K is stacked as the lower layer (back layer), and they are heated and compressed perpendicular to the length direction of the wood grain, resistance (compressive stress) occurs at the boundary between the pre-surface-layer-processed lumber NW11 and the pre-lower-layer-processed lumber NW12 because the wood structure is different (the wood structure is discontinuous), and so the design surface D side of the pre-surface-layer-processed lumber NW11 closer to the movable press platen 10A can be greatly compressed. Furthermore, because the pre-surface-layer-processed lumber NW11 contains knots K and the knots K are hard, the thickness between the hard knots K of the pre-surface-layer-processed lumber NW11 and the design surface D can be greatly compressed. Furthermore, the lower layer pre-processing lumber NW12 also has knots K, and the knots K of the lower layer pre-processing lumber NW12 press against and deform the soft parts without knots of the pre-surface layer processing lumber NW11, bringing the knots K of the lower layer pre-processing lumber NW12 closer to the design surface D. This also allows for a significant compression of the thickness between the hard knots K of the lower layer pre-processing lumber NW12 and the design surface D. This makes it possible to increase the compression rate on the design surface D side, and increase the surface hardness. In this case, even if the pre-surface layer processing lumber NW11 has knots K, by pressing against and deforming the soft parts without knots of the lower layer pre-processing lumber NW12 in the thickness direction, loads are less likely to be applied to the knots K of the pre-surface layer processing lumber NW11, and cracks, etc., are less likely to occur in the knots K of the pre-surface layer processing lumber NW11. Similarly, by pressing and deforming the soft parts of the pre-surface processing wood NW11 that are free of knots in the thickness direction, the knots K in the pre-lower layer processing wood NW12 are less likely to be subjected to stress, and the knots K in the pre-lower layer processing wood NW12 are less likely to crack.

[0248] In particular, in the fifth embodiment, the pre-surface-layer-processed lumber NW11 having knots K and the pre-lower-layer-processed lumber NW12 having knots K are laminated perpendicular to the longitudinal direction of the grain with their grains aligned, and the knots K of the pre-lower-layer-processed lumber NW12 press against the softer, knot-free portions of the pre-surface-layer-processed lumber NW11, easily deforming them and penetrating deeply. Therefore, the knots K of the pre-lower-layer-processed lumber NW12 are more likely to approach the design surface D, which increases the compressibility of the thickness between the hard knots K and the design surface D and further increases the surface hardness. Furthermore, the presence of knots K in the pre-surface-layer-processed lumber NW11 also increases the compressibility of the thickness between the hard knots K and the design surface D and further increases the surface hardness. Furthermore, even if there are knots K in the pre-surface-processing lumber NW11, the knots K in the pre-surface-processing lumber NW11 press against and deform soft parts of the pre-surface-processing lumber NW12 that are free of knots K, making it difficult for a load to be placed on the knots K in the pre-surface-processing lumber NW11, and also because the knots K in the pre-surface-processing lumber NW12 press against and deform soft parts of the pre-surface-processing lumber NW11 that are free of knots K and making it difficult for a load to be placed on the knots K in the pre-surface-processing lumber NW12, cracking of the knots K due to heating and compression is prevented.

[0249] That is, the laminated plastically processed timber LPW5 of the fifth embodiment is made by laminating and bonding the surface-layer plastically processed timber PW11 and the lower-layer plastically processed timber PW12 that constitute it with the longitudinal direction of the wood grain aligned with each other, so that the knots K of the lower-layer plastically processed timber PW12 press and deform the soft parts without knots K of the surface-layer plastically processed timber PW11, and the knots K of the lower-layer plastically processed timber PW12 move closer to the design surface D, thereby increasing the compression rate of the thickness between the hard knots K and the design surface D and further increasing the surface hardness. Also, the presence of hard knots K in the surface-layer plastically processed timber PW11 increases the compression rate of the thickness between the hard knots K of the surface-layer plastically processed timber PW11 and the design surface D and further increasing the surface hardness. At this time, the knots K of the surface plastically processed wood PW11 press heavily against the soft parts of the lower plastically processed wood PW12 that are free of knots K, deforming them, and the knots K of the lower plastically processed wood PW12 press heavily against the soft parts of the surface plastically processed wood PW11 that are free of knots K, deforming them, so that the surface hardness can be increased without causing cracks at the knots K.

[0250] As described above, preferably, the unprocessed wood NW11 having knots K has its surface side facing the design surface D, with the flat grain or longitudinal grain side of the wood surface facing the design surface D, and the opposite side facing the back side facing the unprocessed wood NW12 having knots K. Also, the unprocessed wood NW12 having knots K has its back side facing the unprocessed wood NW11, with the flat grain or longitudinal grain side of the wood surface facing the design surface D. The laminated pre-processed lumber LNW5, which is made by stacking pre-processed lumber NW11 with knots K and pre-processed lumber NW12 with knots K, with the grain side facing away from the design side, is heated and compressed perpendicular to the length direction of the wood grain. This increases the resistance at the boundary between the pre-processed lumber NW11 and the pre-processed lumber NW12, allowing for greater compression of the design surface D side of the pre-processed lumber NW11 closer to the movable press platen 10A. This increases the compression rate of the design surface D side of the laminated plastically processed lumber LPW5, thereby increasing the surface hardness. Furthermore, this reduces variation in surface hardness and stabilizes the surface hardness characteristics.

[0251] That is, the design surface D side of the surface plastically processed wood PW11 that constitutes the laminated plastically processed lumber LPW5 is the plain grain or straight grain side of the wood surface, and the opposite side, the bonding surface with the lower layer plastically processed wood PW12, is the plain grain or straight grain side of the wood back, and the bonding surface with the surface plastically processed wood PW11 of the lower layer plastically processed wood PW12 that constitutes the laminated plastically processed lumber LPW5 is the plain grain or straight grain side of the wood back, and the opposite side, the anti-design surface, is the plain grain or straight grain side of the wood surface. In this case, it is possible to increase the compression ratio of the design surface D side of the laminated plastically processed lumber LPW5 and increase the surface hardness. Furthermore, variation in surface hardness can be reduced, and the surface hardness characteristics can be more stabilized.

[0252] Furthermore, the plain grain or straight grain side of the surface of the surface plastically processed timber PW11 is the press surface that the movable press platen 10A abuts against, and the plain grain or straight grain side of the surface of the lower layer plastically processed timber PW12 is the press surface that the fixed press platen 10B abuts against, and the wood is compressed in a compression direction that causes little distortion, internal resistance, or stress due to compression.In addition, the plain grain or straight grain side of the surface of the wood is located on the front and back surfaces of the laminated plastically processed timber LPW5, and the anisotropy of shrinkage is balanced, so even if expansion and contraction forces occur due to changes in ambient conditions such as humidity, moisture, and dryness after compaction processing, distortion is unlikely to occur, and the dimensional and shape stability is high.

[0253] Preferably, the maximum value θ2 of the acute angle (annual ring angle) θ2 formed by the annual ring line GR2 appearing on the end grain surface of the lower layer plastically processed wood PW12 having knots K and the adhesive boundary line BL of the surface layer plastically processed wood PW11 and the lower layer plastically processed wood PW12 max2 The maximum value θ1 of the acute angle between the annual ring line GR1 and the adhesive boundary line BL on the end grain surface of the surface plastically processed wood PW11 with knot K is max1 is larger than (θ max2 >θ max1 ). In other words, the surface-processed wood PW11 with knots K has the maximum value θ1 on the acute side of the intersection angle (annual ring angle) θ1 between the annual ring line GR1 appearing on the butt end surface and the adhesive boundary line BL of the surface-processed wood PW11 and the lower-processed wood PW12. max1 The maximum value θ2 of the acute angle between the annual ring line GR2 and the adhesive boundary line BL on the cut end surface of the lower layer plastically processed wood PW11 containing knot K. max2 It is smaller than

[0254] The maximum value of the annual ring angle θ1 in the surface plastically processed wood PW11 with knots K is max1 The maximum value of the ring angle θ2 in the lower layer plastically processed wood PW12 with knot K is max2In the laminated plastically processed timber LPW5 consisting of the surface-layer plastically processed timber PW11 and the lower-layer plastically processed timber PW1, which are smaller than the surface-layer plastically processed timber PW1, the lower-layer plastically processed timber PW12 is resistant to compression (has high compressive strength), so the design surface D side of the surface-layer plastically processed timber PW11 is strongly compressed. Therefore, the compression ratio of the design surface D side of the laminated plastically processed timber LPW5 can be increased, and the surface hardness can be further increased. Furthermore, the variation in surface hardness can be reduced, and the surface hardness characteristics can be stabilized.

[0255] Furthermore, the maximum value of the annual ring angle θ2 in the lower layer plastically processed wood PW12 with knot K is max2 However, if the angle is preferably in the range of 40° or more and less than 90°, and more preferably 45° or more and 85° or less, the lower layer plastically processed wood PW12 is more resistant to compression (has high compressive strength), and the design surface D side of the surface layer plastically processed wood PW11 is significantly compressed. Therefore, the compression ratio of the design surface D side of the laminated plastically processed wood LPW5 can be further increased, and the surface hardness can be further increased.

[0256] In addition, the maximum value of the annual ring angle θ1 in the surface plastically processed wood PW11 with knot K is max1 However, if the angle is preferably in the range of 10° or more and 50° or less, more preferably 10° or more and 45° or less, the surface plastically processed wood PW11 is relatively easy to compress even if knots K are present, and therefore the area between the design surface D side of the surface plastically processed wood PW11 and the knots K can be significantly compressed, thereby further increasing the compression rate of the design surface D side of the laminated plastically processed wood LPW5 and further increasing the surface hardness. The knots K are prevented from being crushed, and even if the knots K are exposed on the design surface D, the aesthetic appearance of the knots K can be improved.

[0257] In addition, the occupancy rate of knots K on the surface of the surface plastically processed wood PW11 containing knots K and the surface of the lower layer plastically processed wood PW12 containing knots K is preferably within the range of 0.5 to 20%, more preferably 1 to 15%, and even more preferably 3 to 15%, which makes it less likely for cracks and fissures to occur around the knots K, and allows the design surface D side of the surface plastically processed wood PW11 to be significantly compressed, thereby further increasing the surface hardness, and further reducing variation in surface hardness and making the surface hardness characteristics more stable. Preferably, by making the proportion of knots K in the surface layer plastically processed wood PW11 smaller than the proportion of knots K in the lower layer plastically processed wood PW12, the design surface D side can be compressed more greatly without causing cracking or crushing of the knots K in the surface layer plastically processed wood PW11, thereby increasing the surface hardness and improving the aesthetic appearance of the knots K even if they are exposed on the design surface D.

[0258] In this way, by stacking pre-surface-processed wood NW11 containing knots K on top of pre-lower-layer-processed wood NW12 containing knots K underneath and heating and compressing them perpendicular to the length direction of the wood grain, the knots K of the pre-surface-processed wood NW11 press and deform the knot-free parts of the pre-lower-layer-processed wood NW12, and the knots K of the pre-lower-layer-processed wood NW12 press and deform the knot-free parts of the pre-surface-processed wood NW11, and the thickness between the design surface D and the knots K is highly compressed without causing the knots K to crack, so that the design surface D side of the pre-surface-processed wood NW11 is compressed more than the boundary line BL side with the pre-lower-layer-processed wood NW12.

[0259] In the laminated plastically processed wood LPW5 of the fifth embodiment, the Brinell hardness (HB) of the design surface D side of the surface plastically processed wood PW11 is 10 N / mm 2 More than 50N / mm 2 Within this range, cracks and fissures are unlikely to occur around the knots K, and even when used as flooring or the like, heel marks are unlikely to occur. Furthermore, even when used as a tabletop or the like, scratches caused by writing, cutters, or collisions with heavy objects such as desk legs are unlikely to occur, resulting in excellent maintenance of aesthetic appearance. More preferably, the Brinell hardness of the design surface D side of the wood NW11 before surface processing is 25 N / mm 2More than 50N / mm 2 More preferably, 30 N / mm 2 More than 50N / mm², particularly preferably 35N / mm² 2 More than 50N / mm 2 It is within the following range:

[0260] Furthermore, in the laminated plastically processed wood LPW5 of the fifth embodiment, the thickness of the surface layer plastically processed wood PW11 is preferably 0.3 to 1.0 times, and more preferably 0.5 to 0.6 times, the thickness of the lower layer plastically processed wood PW12 due to compaction. This thickness makes it difficult for cracks or fractures to occur due to compression, and high surface hardness can be obtained. Furthermore, the variation in surface hardness can be reduced, and the surface hardness characteristics can be more stabilized.

[0261] The laminated plastically processed wood LPW5 of this fifth embodiment has an overall thickness of preferably 10 mm to 40 mm, more preferably 10 mm to 35 mm, and even more preferably 10 mm to 30 mm, the thickness of the surface plastically processed wood PW11 is preferably 3 mm to 20 mm, more preferably 4 mm to 15 mm, and even more preferably 4 mm to 12 mm, and the thickness of the lower layer plastically processed wood PW12 is preferably 5 mm to 25 mm, more preferably 5 mm to 20 mm, and even more preferably 6 mm to 20 mm.Within these ranges, high surface hardness is ensured, but the thin overall thickness makes it lightweight.

[0262] Furthermore, the laminated plastically processed wood LPW5 of this fifth embodiment has a compression ratio of preferably 30% to 70%, more preferably 35% to 70%, relative to the air-dry specific gravity of the wood species of the original unprocessed wood NW, the surface plastically processed wood PW11 has a compression ratio of preferably 50% to 75%, more preferably 55% to 75%, relative to the air-dry specific gravity of the wood species of the original unprocessed wood NW, and the lower layer plastically processed wood PW12 has a compression ratio of preferably 15% to 55%, more preferably 20 to 50%, relative to the air-dry specific gravity of the wood species of the original unprocessed wood NW. Within these compression ratio ranges, lightweight and high surface hardness can be achieved at the same time.

[0263] In addition, the air-dry specific gravity of the laminated plastically processed lumber LPW5 of the fifth embodiment is preferably in the range of 1.2 to 2.5 times, more preferably 1.5 to 2.0 times, the air-dry specific gravity of the original unprocessed lumber NW. If it is in this range, cracks and fractures due to compression are unlikely to occur, and both strength and lightness can be achieved.

[0264] In terms of the compression ratio of the thickness of the unprocessed wood NW11, 12, the laminated plastically processed wood LPW5 of the fifth embodiment preferably has a compression ratio of 30 to 75%, more preferably 35 to 75%, relative to the thickness of the unprocessed wood LNW1, the surface layer plastically processed wood PW11 has a compression ratio of 50 to 75%, more preferably 55 to 75%, relative to the thickness of the original surface layer unprocessed wood NW11, and the lower layer plastically processed wood PW12 has a compression ratio of 15 to 55%, more preferably 20 to 50%, relative to the thickness of the original lower layer unprocessed wood NW12. Within these compression ratio ranges, lightweight and high surface hardness can be achieved at the same time.

[0265] In this way, in this embodiment 5, a lower layer pre-processed timber NW12 having knots K is layered underneath a surface layer pre-processed timber NW11 having knots K via an adhesive to form a laminated pre-processed timber LNW5, and this laminated pre-processed timber LNW5 is then compacted to form laminated plastically processed timber LPW5.By taking advantage of the fact that resistance occurs at the boundary between the surface layer pre-processed timber NW11 and the lower layer pre-processed timber NW12 when compressed due to the different types of wood, it is made easier to compress the design surface D side of the surface layer pre-processed timber NW11 closer to the movable press platen 10A.Furthermore, by taking advantage of the hardness of the knots K in the surface layer pre-processed timber NW11 and the lower layer pre-processed timber NW12, the compression rate of the thickness between the hard knots K and the design surface D side is increased, thereby increasing the surface hardness of the laminated plastically processed timber LPW5. Furthermore, since the knots K of the pre-surface processing wood NW11 press against and deform the soft parts without knots K of the lower layer pre-processing wood NW12, it is difficult for a load to be placed on the knots K of the pre-surface processing wood NW11, and since the knots K of the lower layer pre-processing wood NW12 press against and deform the soft parts without knots K of the pre-surface processing wood NW11, it is difficult for a load to be placed on the knots K of the lower layer pre-processing wood NW12, so that the knots K are less likely to crack due to heating and compression.

[0266] As explained above, the laminated plastically processed wood LPW5 of the above-mentioned embodiment 5 is a laminated plastically processed wood PLW5 in which two pieces of wood, namely, surface layer plastically processed wood PW11 and lower layer plastically processed wood PW12, are laminated and glued perpendicular to the longitudinal direction of the wood grain, and which has been plastically processed by heating and compressing them perpendicular to the longitudinal direction of the wood grain and then fixing them, and the surface layer plastically processed wood PW11 which forms the design surface D and the lower layer plastically processed wood PW12 glued underneath have knots K, and by heating and compressing, the lower layer plastically processed wood PW12 glued to the surface layer plastically processed wood PW11 is pressed and deformed by the knots K of the surface layer plastically processed wood PW11, and the lower layer plastically processed wood PW12 is pressed and deformed by the knots K of the surface layer plastically processed wood PW11, so that the design surface D side of the surface layer plastically processed wood PW11 is more compressed than the boundary side with the lower layer plastically processed wood PW12 (the side of the adhesive boundary line BL).

[0267] According to the laminated plastically processed wood LPW5 of the above-mentioned embodiment 5, two pieces of wood, namely, surface pre-processed wood NW11 and lower layer pre-processed wood NW12, are stacked and then heated and compressed perpendicular to the length direction of the wood grain, and then compressed and fixed.In other words, it is a laminated pre-processed wood LNW5 in which surface pre-processed wood NW11 and lower layer pre-processed wood NW12 are stacked, and then plastically processed.When heated and compressed perpendicular to the length direction of the wood grain, resistance occurs at the boundary between the stacked surface pre-processed wood NW11 and lower layer pre-processed wood NW12, thereby increasing the compression rate on the design surface D side. In addition, due to the heated compression, the surface plastically processed wood PW11 is pressed and deformed by the knots K of the lower layer plastically processed wood PW12, and further, the knots K of the surface plastically processed wood PW11 press and deform the lower layer plastically processed wood PW12, so that the thickness between the hard knots K of the surface plastically processed wood PW11 and the lower layer plastically processed wood PW12 and the design surface D is highly compressed without causing cracks in the knots K, and as a result, the design surface D side of the surface plastically processed wood PW11 is more compressed than the boundary side with the lower layer plastically processed wood PW12.

[0268] Thus, according to the laminated plastically processed wood LPW5 of the above-mentioned embodiment 5, due to the laminated structure of the surface plastically processed wood PW11 and the lower layer plastically processed wood PW12, and because the hard knots K of the surface plastically processed wood PW11 and the lower layer plastically processed wood PW12 are less likely to press and deform the surface plastically processed wood PW11 and the lower layer plastically processed wood PW12, and because the hard knots K of the lower layer plastically processed wood PW12 are less likely to apply load to the knots K by pressing and deforming the surface plastically processed wood PW11 and the lower layer plastically processed wood PW12, and further, because the hard knots K of the lower layer plastically processed wood PW12 press and deform the surface plastically processed wood PW11 and move closer to the design surface D, the compression rate of the thickness between the hard knots K of the surface plastically processed wood PW11 and the hard knots K of the lower layer plastically processed wood PW11 that are close to the design surface D can be increased without causing cracks in the knots K, and the surface hardness on the design surface D side can be increased. In particular, since knots K are present in both the surface plastically processed wood PW11 and the lower layer plastically processed wood PW12, stress during heating and compression is easily distributed to both the surface plastically processed wood PW11 and the lower layer plastically processed wood PW12, making it possible to increase surface hardness without increasing the probability of cracks, etc.

[0269] In addition, deformation due to pressure from the knot K means that, when viewed from the end surface of the laminated plastically processed wood LPW5, the adhesive boundary line BL between the surface plastically processed wood PW11 and the lower layer plastically processed wood PW12 is bent, and when viewed from the adhesive surfaces (opposing surfaces) of the pre-surface processed wood NW11 and the lower layer plastically processed wood PW12, the knot K is convex on the adhesive surface of the surface plastically processed wood PW11, and the portion of the adhesive surface of the lower layer plastically processed wood PW12 that has received the knot K is deformed concavely, and the knot K is also convex on the adhesive surface of the lower layer plastically processed wood PW12, and the portion of the adhesive surface of the surface plastically processed wood PW11 that has received the knot K is deformed concavely.

[0270] In the laminated plastically processed wood LPW5 according to the above-mentioned embodiment 5, the surface layer plastically processed wood PW11 and the lower layer plastically processed wood PW12 are laminated and glued together with the longitudinal direction of the wood grain aligned with each other, so that the surface layer plastically processed wood PW11 is pressed and deformed by the knots K of the lower layer plastically processed wood PW12, and further, the lower layer plastically processed wood PW12 is pressed and deformed by the knots K of the surface layer plastically processed wood PW11, preventing cracking of the knots K while enabling greater compression between the hard knots K and the design surface D, thereby further increasing the compression rate on the design surface D side and further increasing the surface hardness, thereby reducing variation in surface hardness and stabilizing the surface hardness characteristics.

[0271] In the laminated plastically processed timber LPW5 according to the fifth embodiment, when the surface layer plastically processed timber PW11 and the lower layer plastically processed timber PW12 are laminated and bonded together with their backsides facing each other, the anisotropy of the shrinkage rate of the timber is balanced. Therefore, even if expansion and contraction forces occur due to changes in the surrounding annular conditions, distortion, knots, cracks, etc. are unlikely to occur, and the dimensional and shape stability is high. Furthermore, when heated and compressed perpendicular to the length direction of the wood grain, higher resistance (compressive stress) occurs at the boundary between the laminated timber pieces, which allows for a higher compression rate on the design surface D. This improves surface hardness, reduces surface hardness variation, and stabilizes surface hardness characteristics.

[0272] That is, in the laminated plastically processed timber LPW5 according to the fifth embodiment, the design surface D of the surface layer plastically processed timber PW11 is a plain grain surface or a straight grain surface on the front side of the wood, and the opposite surface, which faces the lower layer plastically processed timber PW12, is a plain grain surface or a straight grain surface on the back side of the wood, and the surface of the lower layer plastically processed timber PW12 which faces the surface layer plastically processed timber PW11 is a plain grain surface or a straight grain surface on the back side of the wood, Because the design surface D is the plain grain or straight grain surface on the front side of the wood, it is easily compressed, and furthermore, because the surface plastically processed wood PW11 and the lower layer plastically processed wood PW12 are laminated with the plain grain or straight grain surfaces on the back side of the wood facing each other, the resistance (internal stress) at the boundary between the pieces of wood (bonding boundary line BL) is high when heated and compressed perpendicular to the length of the wood grain, allowing for greater compression of the design surface D of the surface plastically processed wood PW11. This makes it possible to improve the surface hardness on the design surface D side, reduce variation in surface hardness, and more stabilize the surface hardness characteristics.

[0273] The laminated plastically processed wood LPW5 according to the fifth embodiment has a Brinell hardness of 10 N / mm 2 More than 50N / mm 2 Less than or equal to 25N / mm 2 More than 50N / mm 2 More preferably, 30 N / mm 2 More than 50N / mm², particularly preferably 35N / mm² 2 More than 50N / mm 2 This makes it difficult for heel marks to form when used as flooring or the like, and also makes it difficult for scratches caused by writing, cutters, or the like, or scratches caused by heavy objects such as desk legs to collide with it when used as a tabletop or the like, resulting in excellent maintenance of aesthetic appearance.

[0274] In the laminated plastically processed timber LPW5 according to the fifth embodiment, preferably, the lower layer plastically processed timber PW12 having knots K has a maximum value θ of the acute angle θ2 formed by the annual ring line GR2 appearing on the butt end surface and the adhesive boundary line BL of the surface layer plastically processed timber PW11 and the lower layer plastically processed timber PW12. max2The maximum value θ1 of the acute angle between the annual ring line GR1 and the adhesive boundary line BL on the end grain surface of the surface plastically processed wood PW11 with knot K is max1 Therefore, since the lower layer plastically processed wood PW12 is difficult to compress, the compression ratio of the design surface D of the surface layer plastically processed wood PW11 can be increased, which enables the surface hardness to be improved, and the variation in surface hardness can be reduced, resulting in more stable surface hardness characteristics.

[0275] The laminated plastically processed timber LPW5 according to the fifth embodiment has a maximum value θ of the acute angle θ2 formed by the annual ring line GR2 appearing on the end grain surface of the lower-layer plastically processed timber PW12 having knots K and the adhesive boundary line BL of the surface-layer plastically processed timber PW11 and the lower-layer plastically processed timber PW12. max2 is preferably 40° or more and less than 90°, more preferably 45° or more and 85° or less, so that the lower layer plastically processed wood PW12 is difficult to compress, and the compression ratio of the design surface D side of the surface layer plastically processed wood PW11 can be increased. As a result, the surface hardness can be further improved, the variation in surface hardness can be reduced, and the surface hardness characteristics can be more stabilized.

[0276] The laminated plastically processed timber LPW5 according to the fifth embodiment has a maximum value θ of the acute-angle crossing angle θ1 formed by the annual ring line GR1 appearing on the end grain surface of the surface-layer plastically processed timber PW11 having knots K and the adhesive boundary line BL between the surface-layer plastically processed timber PW11 and the lower-layer plastically processed timber PW12. max1 is preferably 10° or more and 50° or less, more preferably 10° or more and 45° or less, so that even if knots K are present, the surface plastically processed wood PW11 is relatively easily compressed, and the area between the design surface D side of the surface plastically processed wood PW11 and the knots K can be greatly compressed, thereby further increasing the compression rate of the design surface D side of the laminated plastically processed wood LPW5 and further increasing the surface hardness.

[0277] Furthermore, in the laminated plastically processed wood LPW5 of the above-mentioned embodiment 5, the occupancy rate of knots K on the material surface of the surface layer plastically processed wood PW11 having knots K and the lower layer plastically processed wood PW12 having knots K is preferably within the range of 0.5 to 20%, more preferably 1 to 15%, and even more preferably 3 to 15%, thereby ensuring strength that is less susceptible to cracks, fissures, etc., while reducing variation in surface hardness and stabilizing surface hardness characteristics.

[0278] [Embodiment 6] Next, a laminated plastically processed wooden piece LPW6 according to a sixth embodiment of the present invention will be described with reference to FIG. The laminated plastically processed lumber LPW6 of this embodiment 6 is made by stacking three or more pieces (three pieces) of unprocessed lumber NW11, NW12, NW13, ..., NWn perpendicular to the length direction of the grain using adhesive, and plastically processing (compacting) them by heating, compressing and fixing them perpendicular to the length direction of the grain. In this sixth embodiment, cedar or cypress wood is also used for the three or more pieces of raw lumber NW11, NW12, NW13, ..., NWn. That is, the plastically processed lumber PW11, PW12, PW13, ..., PWn constituting the laminated plastically processed lumber LPW6 are made of cedar or cypress wood.

[0279] In the laminated plastically processed timber LPW6 of this embodiment 6, a surface layer pre-processed timber NW11 having one or more knots K on the surface layer facing the design surface D is used, and a lower layer pre-processed timber NW12 also having knots K is layered directly below the surface layer pre-processed timber NW1 having knots K. Furthermore, one or more other pieces of pre-processed timber NW13, ..., NWn are layered below the lower layer pre-processed timber NW12. The surface layer pre-processed timber NW11 having knots K, the lower layer pre-processed timber NW12 having knots K, and one or more other pieces of pre-processed timber NW13, ..., NWn are layered in the thickness direction, which is perpendicular to the length direction of the wood grain, and are consolidated by heat compression treatment and compression fixation treatment perpendicular to the length direction of the wood grain. The laminated plastically processed timber LPW6 consists of surface layer plastically processed timber PW11 having knots K, lower layer plastically processed timber PW12 having knots K, and one or more other pieces of plastically processed timber PW13, ..., PWn, which are layered and bonded together.

[0280] In Figure 9, the laminated plastically processed wood LPW6 of this embodiment 6 is described as an example in which another piece of pre-processed wood NW13 is placed under the lower layer of pre-processed wood NW12, and the three pieces of pre-processed wood NW11, NW12, and NW13 are stacked perpendicular to the length direction of the wood grain using adhesive, and plastically processed by heating, compressing, and fixing perpendicular to the length direction of the wood grain. One or more pieces of unprocessed wood NW13,...,NWn overlapping below the lower layer unprocessed wood NW12, i.e., one or more pieces of plastically processed wood PW13,...,PWn overlapping below the lower layer plastically processed wood PW12, may or may not have knots K.

[0281] In the sixth embodiment as well, the surface layer unprocessed timber NW11 having knots K and the lower layer unprocessed timber NW12 having knots K are stacked perpendicular to the length direction of the wood grain with the length direction of the wood grain aligned. Furthermore, one or more other pieces of unprocessed timber NW13, ..., NWn overlapping below the lower layer unprocessed timber NW12 are also stacked perpendicular to the length direction of the wood grain with the length direction of the wood grain aligned with the length direction of the surface layer unprocessed timber NW11 and the lower layer unprocessed timber NW12. That is, the laminated plastically processed timber LPW6 of this embodiment 6 is made up of surface layer plastically processed timber PW11, lower layer plastically processed timber PW12, and one or more other pieces of plastically processed timber PW13, ..., PWn, which are stacked and glued together with the length directions of the grain of each piece aligned.

[0282] In the laminated plastically processed lumber LPW6 of the sixth embodiment, lumber having knots K is used for the surface layer pre-processed lumber NW11, which is the raw material, and lumber having knots K is used for the lower layer pre-processed lumber NW12, but preferably, flat grain lumber or straight grain lumber is used for the surface layer pre-processed lumber NW11 having knots K and the lower layer pre-processed lumber NW12 having knots K. Furthermore, flat grain lumber or straight grain lumber is preferably used for another one or more pieces of pre-processed lumber NW13, ..., NWn overlapping under the lower layer pre-processed lumber NW12. That is, the surface layer plastically processed timber PW11 and the lower layer unprocessed timber PW12 constituting the laminated plastically processed timber LPW6 of the present embodiment 6 are preferably flat grain timber or straight grain timber. Another one or more pieces of plastically processed timber PW13, ..., PWn overlapping the lower layer plastically processed timber PW12 are also preferably flat grain timber or straight grain timber.

[0283] Also, in this embodiment 6, preferably, as shown in Figure 9, the surface pre-processed timber NW11 having knots K has the flat grain or longitudinal side of its front side facing the design surface D, and the flat grain or longitudinal side of the back side of the wood on the opposite side facing the lower layer pre-processed timber NW12 having knots K, and the flat grain or longitudinal side of the back side of the lower layer pre-processed timber NW12 having knots K faces the surface pre-processed timber NW11, and the flat grain or longitudinal side of the front side of the wood on the opposite side facing the other pre-processed timber NW13 that is placed underneath, and the surface pre-processed timber NW11 having knots K and the lower layer pre-processed timber NW12 without knots K are stacked in their thickness direction.

[0284] With regard to the unprocessed wood NW13 that is stacked under the lower layer unprocessed wood NW12, the side facing the lower layer unprocessed wood NW12 may be the plain grain or straight grain side of the wood front side, or the plain grain or straight grain side of the wood back side. When laminated plastically processed timber LPW6 is composed of surface layer plastically processed timber PW11, lower layer plastically processed timber PW12, and another piece of plastically processed timber PW13 stacked underneath, that is, when three pieces of pre-processed timber NW11, NW12, and NW13, namely surface layer pre-processed timber NW11, lower layer pre-processed timber NW12, and another piece of pre-processed timber NW13 stacked underneath the lower layer pre-processed timber NW12, are compressed to form laminated plastically processed timber LPW6, it is preferable that, as shown in Figure 9, the flat grain or longitudinal grain side of the back of the other piece of pre-processed timber NW13 stacked underneath the lower layer pre-processed timber NW12 be the opposing surface (adhesion surface) to the lower layer pre-processed timber NW12, and the flat grain or longitudinal grain side of the front of the wood be the opposite design surface. If the counter-design surface of another piece of unprocessed wood NW13, which is opposite the design surface D of the surface layer unprocessed wood NW11, is the plain grain or longitudinal grain side of the wood surface, the press surface that the fixed press platen 10B abuts will be the plain grain or longitudinal grain side of the wood surface, and the wood will be compressed in a compression direction with less distortion, internal resistance, and stress due to compression. Therefore, the unprocessed wood NW13, which is layered under the lower layer unprocessed wood NW12 and forms the counter-design surface, will be more likely to compress, and even if it has knots K, it will be less likely to break or crack during compression. In other words, in the case of stacking three pieces of wood, it is preferable that the side of another piece of pre-processed wood NW13 that is placed underneath the lower layer pre-processed wood NW12 be the flat grain or straight grain side on the back side of the wood, and the flat grain or straight grain side on the opposite side be the press surface.This makes it easier for the other piece of pre-processed wood NW13, which is on the side opposite the design surface D of the surface layer pre-processed wood NW11, to be compressed, making it less likely to apply load to the knots K of the lower layer pre-processed wood NW12 and preventing the knots K from cracking.

[0285] If there is an odd number of sheets of plastically processed wood PW13,...,PWn overlapping the lower layer pre-plasticized wood PW12, i.e., if the entire laminated plastically processed wood LPW6 is made up of an odd number of sheets, it is preferable that the counter-design surface of the back layer of plastically processed wood PW13,...,PWn opposite the design surface D of the pre-surface-processed wood NW11 be the flat grain or straight grain side of the wood surface. As a result, since the plastically processed wood PW13,...,PWn forming the counter-design surface is easily compressed, even if it contains knots K, it is less likely to break or crack during compression. However, when carrying out the present invention, the unprocessed wood NW13 that is overlapped under the lower layer unprocessed wood NW12 and forms the opposite design surface may have the flat grain or longitudinal side on the front side of the wood as the surface facing (bonding surface) with the lower layer unprocessed wood NW12, and the flat grain or longitudinal side on the back side of the wood as the opposite design surface. In other words, the opposite design surface of the plastically processed wood PW13 opposite to the design surface D of the surface layer unprocessed wood NW11 may be the flat grain or longitudinal side on the back side of the wood.

[0286] In the sixth embodiment, the surface layer unprocessed lumber NW11 having knots K is used as the surface layer (upper layer), the lower layer unprocessed lumber NW12 having knots K is stacked under the surface layer unprocessed lumber NW11, and one or more other unprocessed lumber NW13, . . ., NWn are stacked under that. At this time, adhesive is applied between the lumber pieces to stack them, thereby forming a laminated unprocessed lumber LNW6, and three or more unprocessed lumber pieces NW11, NW12, NW13, . . ., NWn The laminated pre-processed wood LNW6 consisting of the above is heated and compressed in the thickness direction, i.e., perpendicular to the length direction of the grain of the pre-processed wood NW11, NW12, NW13, ..., NWn, and the compression is fixed to form a laminated plastically processed wood LPW6 consisting of surface layer plastically processed wood PW11, lower layer plastically processed wood PW12, and one or more other pieces of plastically processed wood PW13, ..., PWn, which are laminated and bonded together.

[0287] In the sixth embodiment, when the pre-surface-layer-processed lumber NW11 having knots K is stacked as the surface layer (upper layer) and the pre-lower-layer-processed lumber NW12 having knots K is stacked as the lower layer, and they are heated and compressed perpendicular to the length direction of the wood grain, resistance (compressive stress) occurs at the boundary between the pre-surface-layer-processed lumber NW11 and the pre-lower-layer-processed lumber NW12 because the wood structure is different (the wood structure is discontinuous), and therefore the design surface D side of the pre-surface-layer-processed lumber NW11 closer to the movable press platen 10A can be significantly compressed. Furthermore, because the pre-surface-layer-processed lumber NW11 has knots K and the knots K are hard, the thickness between the hard knots K and the design surface D can be significantly compressed. The lower layer pre-processing wood NW12 also has knots K, and the knots K of the lower layer pre-processing wood NW12 press against and deform the soft parts of the surface layer pre-processing wood NW11 that do not have knots K, bringing the knots K of the lower layer pre-processing wood NW12 closer to the design surface D, which also significantly compresses the thickness between the hard knots K of the lower layer pre-processing wood NW12 and the design surface D. Therefore, it is possible to increase the compression rate on the design surface D side, and the surface hardness can be increased. At this time, even if the surface layer pre-processing wooden piece NW11 has knots K, by pressing and deforming the soft parts of the lower layer pre-processing wooden piece NW12 that are free of knots K in the thickness direction, a load is unlikely to be applied to the knots K in the surface layer pre-processing wooden piece NW11, and cracks, etc., are unlikely to occur in the knots K in the surface layer pre-processing wooden piece NW11. Similarly, by pressing and deforming the soft parts of the lower layer pre-processing wooden piece NW12 that are free of knots K in the surface layer pre-processing wooden piece NW11 in the thickness direction, a load is unlikely to be applied to the knots K in the lower layer pre-processing wooden piece NW12, and cracks, etc., are unlikely to occur in the knots K in the lower layer pre-processing wooden piece NW12.

[0288] In this sixth embodiment, the pre-surface-layer-processed lumber NW11 having knots K and the pre-lower-layer-processed lumber NW12 having knots K are laminated perpendicular to the longitudinal direction of the grain with their grains aligned, and the knots K of the pre-lower-layer-processed lumber NW12 press against the soft, knot-free portions of the pre-surface-layer-processed lumber NW11, easily deforming them and penetrating deeply. Therefore, the knots K of the pre-lower-layer-processed lumber NW12 are more likely to approach the design surface D, further increasing the compressibility of the thickness between the hard knots K and the design surface D, thereby further increasing the surface hardness. Furthermore, the presence of knots K in the pre-surface-layer-processed lumber NW11 also increases the compressibility of the thickness between the hard knots K and the design surface D, thereby further increasing the surface hardness. Furthermore, even if knots K exist in the pre-surface processing wood NW11 and the pre-lower layer processing wood NW12, the knots K in the pre-surface processing wood NW11 press against and deform the soft parts of the pre-lower layer processing wood NW12 that are free of knots K, making it difficult for a load to be placed on the knots K in the pre-surface processing wood NW11, and the knots K in the pre-lower layer processing wood NW12 press against and deform the soft parts of the pre-surface processing wood NW11 that are free of knots K, making it difficult for a load to be placed on the knots K in the pre-lower layer processing wood NW12, so cracking of the knots K due to heating and compression is prevented.

[0289] That is, the laminated plastically processed timber LPW6 of the sixth embodiment is made by laminating and bonding the surface-layer plastically processed timber PW11 and the lower-layer plastically processed timber PW12 that constitute it with the longitudinal direction of the wood grain aligned with each other, so that the knots K of the lower-layer plastically processed timber PW12 press and deform the soft parts without knots of the surface-layer plastically processed timber PW11, and the knots K of the lower-layer unprocessed timber NW12 move closer to the design surface D, thereby increasing the compression rate of the thickness between the hard knots K and the design surface D and further increasing the surface hardness. Also, the presence of hard knots K in the surface-layer plastically processed timber PW11 increases the compression rate of the thickness between the hard knots K of the surface-layer plastically processed timber PW11 and the design surface D and further increasing the surface hardness. At this time, the knots K of the surface plastically processed wood PW11 press heavily against the soft parts of the lower plastically processed wood PW12 that are free of knots K, deforming them, and the knots K of the lower plastically processed wood PW12 press heavily against the soft parts of the surface plastically processed wood PW11 that are free of knots K, deforming them, so that the surface hardness can be increased without causing cracks at the knots K.

[0290] In addition, when the design surface D side of the surface plastically processed wood PW11 that constitutes the laminated plastically processed wood LPW6 is the plain grain or straight grain side of the wood surface, and the opposite side, the bonding surface side opposite to the lower layer plastically processed wood PW12, is the plain grain or straight grain side of the wood back side, and when the bonding surface side opposite to the surface plastically processed wood PW11 of the lower layer plastically processed wood PW12 is the plain grain or straight grain side of the wood back side, and the opposite side, the plain grain or straight grain side of the bonding surface side opposite to the other plastically processed wood PW13 that is overlapping it, the resistance (compressive stress) that occurs at the boundary between the surface plastically processed wood PW11 and the lower layer plastically processed wood PW12 is higher, making it possible to further increase the compression rate of the design surface D side of the laminated plastically processed wood LPW6 and further increase the surface hardness. Furthermore, the variation in surface hardness can be reduced, and the surface hardness characteristics can be more stabilized.

[0291] Furthermore, when the plain grain or straight grain side of the surface of the surface-layered plastically processed lumber PW11 is the press surface that the movable press platen 10A abuts against, and when the plain grain or straight grain side of the surface of another piece of plastically processed lumber PW13 is the press surface that the fixed press platen 10B abuts against, the lumber is compressed in a compression direction that reduces the amount of distortion, internal resistance, and stress due to compression.In addition, the plain grain or straight grain side of the surface of the lumber is located on the front and back surfaces of the laminated plastically processed lumber LPW4, and the anisotropy of shrinkage is balanced.Therefore, even if expansion and contraction forces occur due to changes in ambient conditions such as humidity, moisture, and dryness after compaction processing, distortion is less likely to occur, and the dimensional and shape stability is high. In addition, if the opposite design surface of the plastically processed wood PW13 on the opposite side to the design surface D of the surface plastically processed wood PW11 is the plain grain or straight grain side of the wood surface, the plastically processed wood PW13 forming the opposite design surface is easily compressed, so even if there is a knot K, it is less likely to crack or break during compression.

[0292] Also in the sixth embodiment, preferably, the maximum value θ of the acute angle (annual ring angle) θ2 formed by the annual ring line GR2 appearing on the end grain surface of the lower layer plastically processed wood PW12 having knots K and the adhesive boundary line BL of the surface layer plastically processed wood PW11 and the lower layer plastically processed wood PW12 max2 The maximum value θ1 of the acute angle between the annual ring line GR1 an...

Claims

1. A laminated plastically processed wood product is obtained by laminating and bonding a plurality of pieces of wood in a direction perpendicular to the length direction of the wood grain, and plastically processing the pieces by heat-compressing the pieces in a direction perpendicular to the length direction of the wood grain and fixing the pieces together. This laminated plastically processed wood is characterized in that the lower layer of plastically processed wood that is bonded to the surface layer of plastically processed wood that forms the design surface has knots, and the surface layer of plastically processed wood is pressed and deformed by the knots of the lower layer of plastically processed wood during the heated compression, and the design surface side of the surface layer of plastically processed wood is more highly compressed than the boundary side with the lower layer of plastically processed wood.

2. A laminated plastically processed wood product is obtained by laminating and bonding a plurality of pieces of wood in a direction perpendicular to the length direction of the wood grain, and plastically processing the pieces by heat-compressing the pieces in a direction perpendicular to the length direction of the wood grain and fixing the pieces together. This laminated plastically processed wood is characterized in that the surface layer of plastically processed wood that forms the design surface has knots, and the lower layer of plastically processed wood that is adhered to the surface layer of plastically processed wood is pressed and deformed by the knots of the surface layer of plastically processed wood during the heated compression, and the design surface side of the surface layer of plastically processed wood is more highly compressed than the boundary side with the lower layer of plastically processed wood.

3. A laminated plastically processed wood product is obtained by laminating and bonding a plurality of pieces of wood in a direction perpendicular to the length direction of the wood grain, and plastically processing the pieces by heat-compressing the pieces in a direction perpendicular to the length direction of the wood grain and fixing the pieces together. A laminated plastically processed wood characterized in that the surface layer of plastically processed wood that forms the design surface and the lower layer of plastically processed wood that is bonded to the surface layer of plastically processed wood have knots, and the surface layer of plastically processed wood is pressed and deformed by the knots of the lower layer of plastically processed wood during the heated compression, and the lower layer of plastically processed wood is pressed and deformed by the knots of the surface layer of plastically processed wood, and the design surface side of the surface layer of plastically processed wood is more highly compressed than the lower layer of plastically processed wood.

4. 4. A laminated plastically processed wood material according to claim 1, wherein the surface plastically processed wood material and the lower layer plastically processed wood material are laminated and bonded together with their grains aligned in the longitudinal direction.

5. The surface plastically processed wood has a design surface that is a plain grain or straight grain surface on the front side of the wood, and the surface opposite to the surface plastically processed wood that is a plain grain or straight grain surface on the back side of the wood, Furthermore, the laminated plastically processed wood described in any one of claims 1 to 3 is characterized in that the surface of the lower layer plastically processed wood facing the surface layer plastically processed wood is the plain grain or straight grain surface on the back side of the wood.

6. The Brinell hardness of the design surface of the surface plastically processed wood is 10 N / mm 2 Above, 50N / mm 2 4. The laminated plastically processed wood material according to claim 1, wherein the thickness of the laminated plastically processed wood material is within the following range:

7. The laminated plastically processed wood described in claim 1, characterized in that the maximum value of the acute angle between the annual ring lines appearing on the end grain surface of the lower layer plastically processed wood having knots and the adhesive boundary line of the surface layer plastically processed wood and the lower layer plastically processed wood is greater than the maximum value of the acute angle between the annual ring lines appearing on the end grain surface of the surface layer plastically processed wood and the adhesive boundary line.

8. The lower layer plastically processed wood having the knot has a maximum intersection angle on the acute angle side between the annual ring line appearing on the butt end surface and the adhesive boundary line between the surface layer plastically processed wood and the lower layer plastically processed wood of 40° or more and less than 90°; The surface plastically processed wood is characterized in that the maximum value of the acute angle between the annual ring lines appearing on the end grain surface and the adhesive boundary line is 1° or more and 40° or less.

9. 2. The laminated plastically processed wood according to claim 1, characterized in that the knot-containing lower layer plastically processed wood has a knot occupancy rate on the wood surface in the range of 0.5% or more and 20% or less.

10. The laminated plastically processed wood described in claim 2, characterized in that the maximum value of the acute angle between the annual ring lines appearing on the end grain surface of the surface plastically processed wood having knots and the adhesive boundary line of the surface plastically processed wood and the lower layer plastically processed wood is smaller than the maximum value of the acute angle between the annual ring lines appearing on the end grain surface of the lower layer plastically processed wood and the adhesive boundary line.

11. The surface plastically processed wood having the knots has a maximum intersection angle on the acute side between the annual ring line appearing on the butt end surface and the adhesive boundary line between the surface plastically processed wood and the lower layer plastically processed wood of 10° or more and 50° or less; The laminated plastically processed wood described in claim 10, characterized in that the maximum value of the acute angle between the annual ring lines appearing on the end grain surface and the adhesive boundary line of the lower layer plastically processed wood is 40° or more and less than 90°.

12. The laminated plastically processed wood according to claim 2, characterized in that the knot-containing surface plastically processed wood has a knot occupancy rate on the wood surface in the range of 0.5% or more and 20% or less.

13. The laminated plastically processed wood described in claim 3, characterized in that the maximum value of the acute angle between the annual ring lines appearing on the end grain surface of the lower layer plastically processed wood having the knot and the adhesive boundary line is greater than the maximum value of the acute angle between the annual ring lines appearing on the end grain surface of the surface layer plastically processed wood having the knot and the adhesive boundary line of the surface layer plastically processed wood and the lower layer plastically processed wood.

14. The lower layer plastically processed wood having the knots has a maximum intersection angle on the acute side between the annual ring line appearing on the butt end surface and the adhesive boundary line of 40° or more and less than 90°, The surface plastically processed wood having knots has a maximum intersection angle on the acute side between the annual ring lines appearing on the end grain surface and the adhesive boundary line between the surface plastically processed wood and the lower layer plastically processed wood, which is 10° or more and 50° or less.

15. The laminated plastically processed wood described in claim 3, characterized in that the knot occupancy rate of the surface plastically processed wood having knots and the lower layer plastically processed wood having knots on their material surfaces is in the range of 0.5% or more and 20% or less.

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