Plywood for wooden patterns

Abstract

To provide a plywood for a wooden mold which can restrict decrease of the density of a portion thereof including a notch provided to prevent warpage, warp, or the like, thereby suppressing burning in thermal cutting processing by a laser beam.SOLUTION: A plywood 3 for a wooden mold used as a base material of the wooden mold in which a processing blade is implanted, includes a plywood body 21 having a notch 30 separating woody fibers, a cover plate 23 adhered to the plywood body 21 so as to cover the notch 30, and a coating layer 25 formed so as to cover the cover plate 23.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a plywood for a mold used as a base material of a mold in which a processing blade is implanted, and a method for manufacturing the plywood for a mold.

Background Art

[0002] A sheet-like blank in a developed form such as a paper container is generally manufactured using a mold. As a base material of the mold, plywood for a mold is widely used. The mold is configured by implanting processing blades such as punching blades and ruled line pressing blades in the plywood for a mold. When implanting a processing blade in the plywood for a mold, a narrow and thick-through insertion groove for inserting the processing blade is formed in the plywood for a mold by irradiating the plywood for a mold with a laser beam so as to correspond to the blank shape and the fold of the blank. Then, by inserting the processing blade into the formed insertion groove and implanting it in the plywood for a mold, a mold such as a Thomson punching mold is assembled.

[0003] In the mold as described above, in order to ensure high processing accuracy, it is necessary to form the insertion groove formed in the plywood for a mold with an appropriate groove width, and of course, to prevent the occurrence of warping, twisting, etc. of the plywood for a mold itself. As a method for preventing the occurrence of warping, twisting, etc. of the plywood for a mold itself, there is a method of providing a cut in the plywood body constituting the core of the plywood for a mold so as to divide the wood fiber (for example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In Patent Document 1, when attempting to manufacture highly accurate plywood for wooden patterns by preventing warping, twisting, etc., it is stated that the notches provided in the plywood body should be made to a depth of, for example, 60-70% of the thickness of the plywood body, and are formed by cutting from one side surface of the plywood body toward the other side surface using a special cutting tool.

[0006] The thickness of a cutting tool is greatest at the belly and decreases towards the tip. When a cut is made in the plywood body with such a cutting tool, the gap in the cut is largest in shallow areas, and as the depth increases, the gap in the cut decreases. In the deepest areas, the wood fibers are severed, but the elasticity of the wood fibers keeps the plywood body on both sides of the cut in contact. Thus, in the area with a cut, the density is relatively lower than in the area without a cut due to the gap that is inevitably created by the cutting tool. For this reason, in plywood used for wooden patterns, there is a variation in density between the areas with and without cuts.

[0007] Incidentally, when forming the insertion groove for the processing blade, the laser beam irradiated onto the plywood for the wooden pattern is set to an output that allows the insertion groove to be formed by thermal cutting even when irradiated onto a relatively high-density area that does not include a cut. When using a laser beam set to such an output, thermal cutting is performed without problems when forming an insertion groove in a relatively high-density area of ​​the plywood that does not include a cut, and the insertion groove can be formed to the appropriate groove width. However, even with the same laser beam output, when forming an insertion groove in a relatively low-density area of ​​the plywood that includes a cut, thermal cutting may proceed excessively, and burning may result in a groove width larger than the appropriate width. When a processing blade is inserted and planted in an insertion groove with a groove width larger than the appropriate width, the planting of the processing blade may become loose, and the processing accuracy of the blank will deteriorate.

[0008] The present invention has been made in view of the above problems, and aims to provide a plywood for wooden patterns and a method for manufacturing plywood for wooden patterns that can suppress the decrease in density of the portion including the cuts provided to prevent warping and twisting, thereby suppressing burn damage during thermal cutting with a laser beam. [Means for solving the problem]

[0009] The characteristic configuration of the wooden plywood according to the present invention, which solves the above problems, is as follows: A wooden plywood used as a base material for a wooden mold in which a processing blade is embedded, A plywood body having cuts that divide the wood fibers, A covering plate is adhered to the plywood body so as to cover the aforementioned cutout, A coating layer formed to cover the aforementioned covering plate, The goal is to provide for it.

[0010] In this type of plywood for wooden patterns, the coating layer is formed to cover the covering board. As a result, moisture evaporation from the side of the board covered by the coating layer (coated side) is suppressed compared to moisture evaporation from the side of the board bonded to the plywood body (uncoated side). Therefore, moisture evaporation proceeds relatively more on the uncoated side than on the coated side, and shrinkage progresses more on the uncoated side than on the coated side. This causes a force that results in the covering board warping, with the coated side becoming convex. Consequently, tensile stress remains in the thickness direction and compressive stress remains along the board surface within the plywood body. The portion of the plywood body containing the cuts is where the cross-sectional shape changes abruptly. In other words, where the depth of the cut is small, the gap in the cut is relatively large, and as the depth of the cut increases, the gap in the cut decreases. In the deepest part of the cut and its vicinity, the wood fibers are divided, but the elasticity of the wood fibers keeps the plywood body on both sides of the cut in contact. Of the tensile and compressive stresses remaining inside the plywood body, the compressive stress does not act in the deepest part of the cut and its vicinity where the gap is relatively large, and instead concentrates in the deepest part of the cut and its vicinity where the plywood body on both sides of the cut are in contact (so-called stress concentration). As a result, the plywood body on both sides of the cut are tightly packed in the deepest part of the cut and its vicinity, and the density of this packed area increases relatively compared to the surrounding density. In the part of plywood for wooden patterns that includes a cut, the density decreases due to the gap that inevitably arises when a cut is made, but the density increases in the deepest part of the cut and its vicinity. As a result, the decrease in density in the depth direction of the portion of the plywood used for wooden patterns that includes the cuts can be suppressed. In this way, the decrease in density of the portion including the cuts, which are provided to prevent warping and twisting, can be suppressed, and thus burn damage during thermal cutting by the laser beam when the laser beam is irradiated onto that portion can be suppressed.

[0011] In the wooden plywood according to the present invention, It is preferable that the plywood body portions on both sides of the cut are in close contact with the deepest part of the cut and in its vicinity.

[0012] With this configuration of plywood for wooden patterns, the plywood body portions on both sides of the cut are tightly fitted together in the deepest part of the cut and in its vicinity. As a result, the density of this tightly fitted portion increases relative to the surrounding density, which suppresses the decrease in the overall density in the depth direction of the part of the wooden pattern plywood including the cut. This reduces burn damage during thermal cutting by the laser beam when the laser beam is irradiated onto that portion.

[0013] In the wooden plywood according to the present invention, Preferably, the cut is made at an angle to the thickness direction of the plywood body.

[0014] For example, when embedding a processing blade in plywood for wooden patterns, if the insertion groove for inserting the processing blade, formed in the thickness direction of the plywood body, and the notch, also formed in the thickness direction of the plywood body, are arranged to overlap when viewed in the thickness direction of the plywood body, depending on the size of the gap in the notch, most of the plywood body surrounding the area where the insertion groove is provided may not function to hold the processing blade, potentially leading to a significant decrease in the blade's holding force. With this configuration of plywood for wooden patterns, the notch is formed at an angle to the thickness direction of the plywood body, so that the portion of the plywood body other than the area where the notch and the insertion groove intersect functions to hold the processing blade, thereby suppressing the decrease in the blade's holding force.

[0015] In the wooden plywood according to the present invention, Preferably, the cut is formed at an angle to at least one side of the plywood body.

[0016] When inserting a processing blade into plywood for wooden patterns, the insertion groove for the processing blade, formed in the thickness direction of the plywood body, is often formed parallel to at least one side of the plywood body. If a notch is formed parallel to at least one side of the plywood body, and the relative positions of the insertion groove and the notch coincide or are close, depending on the size of the gap in the notch, most of the plywood body around the area where the insertion groove is provided in the plywood for wooden patterns may not function to hold the processing blade, and the holding force of the processing blade may be significantly reduced. With the plywood for wooden patterns with this configuration, the notch is formed diagonally to at least one side of the plywood body, so that the insertion groove and the notch intersect. Therefore, the part of the plywood body other than the intersection of the notch and the insertion groove functions to hold the processing blade, thus suppressing the reduction in the holding force of the processing blade.

[0017] In the wooden plywood according to the present invention, Preferably, the plywood body is constructed by laminating multiple veneers in which the cuts are formed.

[0018] With this type of plywood construction, warping and twisting of each veneer are prevented by the notches formed in each veneer, thus more effectively preventing warping and twisting of the plywood body, which is made up of multiple laminated veneers. In each veneer, the gap in the notch is relatively large where the notch depth is small, and as the notch depth increases, the gap in the notch decreases. In the deepest part of the notch and its vicinity, the wood fibers are separated, but the elasticity of the wood fibers keeps the veneer portions on both sides of the notch in contact. Of the tensile and compressive stresses remaining inside the plywood body (veneer), the compressive stress does not act in the deep part of the notch and its vicinity where the gap is relatively large, and instead concentrates in the deepest part of the notch and its vicinity where the veneer portions on both sides of the notch are in contact. As a result, the veneer portions on both sides of the notch in the deepest part of the notch and its vicinity are tightly packed, and the density of this tightly packed area increases relatively compared to the surrounding density. In the portion of each veneer containing a cut, the density decreases due to the gaps that inevitably arise as a result of making the cut. However, the density increases in the portion of the cut with the greatest depth and in its vicinity. As a result, the decrease in density in the depth direction of the portion containing the cut in the plywood for wooden patterns, which has a plywood body made up of multiple veneers with cuts formed on it, can be suppressed. In this way, the decrease in density in the portion containing the cut, which is made to prevent warping and twisting, can be suppressed, and thus burn damage during thermal cutting by laser beam when a laser beam is irradiated onto that portion can be suppressed.

[0019] In the wooden plywood according to the present invention, It is preferable that the covering plate is bonded to the plywood body in such a way that the warping that occurs in the covering plate due to the formation of the coating layer is eliminated.

[0020] According to the plywood for a mold of this structure, the force applied to the covering plate to eliminate the warp generated in the covering plate by forming the coating layer causes compressive stress to occur in a form that remains inside the plywood body when the covering plate is adhered to the plywood body. Since this compressive stress is caused by the force applied to the covering plate to eliminate the warp generated in the covering plate, it is a relatively large stress, and the plywood body portions on both sides of the cut at the portion where the depth of the cut is the largest and in its vicinity can be strongly adhered. As a result, it is possible to more effectively suppress a decrease in the density of the portion including the cut in the plywood for a mold, and it is possible to surely suppress burning during thermal cutting with a laser beam.

[0021] In the plywood for a mold according to the present invention, it is preferable that the coating layer has at least one or more of an antiviral action, an antibacterial action, an insect-proof action, and a mold-proof action.

[0022] According to the plywood for a mold of this structure, it is possible to prevent the occurrence of viruses, bacteria, pests, and molds in the plywood for a mold itself by at least one or more of the antiviral action, antibacterial action, insect-proof action, and mold-proof action of the coating layer. As a result, it is possible to keep the sanitary environment of the produced blanks (products) such as paper containers clean, not to mention the production site such as punching processing.

[0023] Next, the characteristic configuration of the manufacturing method of the plywood for a mold according to the present invention for solving the above problems is <s a manufacturing method of plywood for a mold used as a base material of a mold in which a processing blade is implanted, a covering plate adhesion step of adhering a covering plate to a plywood body having a cut for dividing wood fibers so as to cover the cut, a coating layer forming step of forming a coating layer so as to cover the covering plate, " and it is included in this.

[0024] In the manufacturing method for wooden mold plywood with this configuration, a coating layer formation step is performed in which a coating layer is formed to cover the covering plate that has been bonded to the plywood body through the covering plate bonding step. As a result, since the coating layer is formed to cover the covering plate, the evaporation of moisture from the side of the covering plate that is covered by the coating layer (coated side) is suppressed more than the evaporation of moisture from the side of the covering plate that is bonded to the plywood body (uncoated side). Therefore, in the covering plate, the evaporation of moisture proceeds relatively more on the uncoated side than on the coated side, and the shrinkage effect of the uncoated side progresses more on the uncoated side than on the coated side. As a result, the covering plate attempts to warp in a way that causes a convex shape on the coated side, but because the covering plate is bonded to the plywood body, it cannot warp, and the compressive stress caused by the force that would have caused the warp remains inside the plywood body. The deepest part of the cut and the plywood body portions on both sides of the cut near it are tightly bound together by the action of residual compressive stress within the plywood body, and the density of this tightly bound portion increases relative to the surrounding density. As a result, the decrease in density of the entire depth-direction portion of the plywood for wooden patterns, including the cut, can be suppressed. In this way, the decrease in density of the portion including the cut, which is provided to prevent warping and twisting, can be suppressed, and thus burn damage during thermal cutting by the laser beam when the laser beam is irradiated onto that portion can be suppressed.

[0025] Furthermore, the characteristic configuration of the method for manufacturing wooden plywood according to the present invention, which solves the above problems, is as follows: A method for manufacturing wooden plywood used as a base material for a wooden mold in which a processing blade is embedded, A coating layer formation step in which a coating layer is formed so as to cover the covering plate, A covering plate bonding step is performed in which a covering plate, which has warped due to the formation of the coating layer on a plywood body having cuts that divide the wood fibers, is bonded to the plywood body in a manner that covers the cuts and eliminates the warping, The purpose is to include.

[0026] In the manufacturing method of wooden pattern plywood with this configuration, when the coating layer is formed to cover the covering board by the coating layer formation process, the evaporation of moisture from the board surface covered by the coating layer (coated side board surface) is suppressed more than the evaporation of moisture from the board surface that is bonded to the plywood body (uncoated side board surface). Therefore, in the covering board, moisture evaporation proceeds relatively more on the uncoated side board surface than on the coated side board surface, and the shrinkage effect of the uncoated side board surface proceeds more than on the coated side board surface. As a result, the covering board warps in a convex shape on the coated side board surface. In the covering board bonding process, the covering board, which has warped due to the formation of the coating layer, is bonded to the plywood body, which has cuts that divide the wood fibers, so as to cover the cuts in the plywood body and eliminate the warp. Therefore, the force applied to the covering board to eliminate the warp caused by the formation of the coating layer is converted into compressive stress in the form that remains inside the plywood body when the covering board is bonded to the plywood body. This compressive stress is relatively large because it is caused by the force applied to the covering plate to eliminate warping that has occurred in the covering plate. This allows for strong adhesion between the plywood body on both sides of the cut, particularly at the deepest part of the cut and in its vicinity. As a result, the decrease in density in the part of the wooden pattern plywood including the cut can be suppressed more effectively, and burn damage during thermal cutting with a laser beam can be reliably prevented. [Brief explanation of the drawing]

[0027] [Figure 1] Figure 1 is an overall perspective view of a wooden mold using plywood for wooden molds as a base material according to one embodiment of the present invention. [Figure 2] Figure 2 is a cross-sectional view of the main part of the wooden mold where the processing blade is installed. [Figure 3] Figure 3 is a cross-sectional view of a wooden pattern plywood according to one embodiment of the present invention, before the insertion groove is formed. [Figure 4] Figure 4 is an enlarged cross-sectional view of the main part of the plywood for the wooden pattern, including the cutouts. [Figure 5]Figure 5 is an explanatory diagram of the first method for manufacturing plywood for wooden patterns. [Figure 6] Figure 6 is an explanatory diagram of the second method for manufacturing plywood for wooden patterns. [Figure 7] Figure 7 is a cross-sectional view of the plywood for the wooden pattern according to another embodiment 1, before the insertion groove is formed. [Figure 8] Figure 8 is a plan view of the plywood body that constitutes the wooden pattern plywood according to another embodiment 2. [Figure 9] Figure 9 is a perspective view illustrating the structure of the plywood body that constitutes the wooden pattern plywood according to another embodiment 3. [Modes for carrying out the invention]

[0028] The present invention will now be described with reference to the drawings. In the following embodiments, a die-cutting mold (Thomson die) for manufacturing a sheet-like blank, which is the unfolded form of a paper container, will be used as an example. However, the present invention is not intended to be limited to the embodiments or configurations shown in the drawings described below. In each figure, it is shown that the plywood for die-cutting according to the present invention is composed of multiple layers, but the thickness relationships of each layer have been exaggerated or simplified as appropriate for the sake of ease of explanation, and do not strictly reflect the relative thicknesses (scale) of each layer in actual plywood for die-cutting.

[0029] <Wooden mold construction> Figure 1 is an overall perspective view of a wooden pattern 1 using a wooden pattern plywood 3 as a base material according to one embodiment of the present invention. The wooden pattern 1 shown in Figure 1 comprises a wooden pattern plywood 3 that is rectangular in plan view and a processing blade 5 embedded in the wooden pattern plywood 3. The processing blade 5 includes a punching blade 7 and a creasing blade 9. The punching blade 7 is positioned to match the outer shape of the blank to be manufactured. The creasing blade 9 is positioned to correspond to the folds of the blank to be manufactured.

[0030] Figure 2 is a cross-sectional view of the main part of the wooden pattern 1 where the processing blade 5 is installed. As shown in Figure 2, the wooden pattern 1 is constructed by inserting and installing punching blades 7 and creasing blades 9 into narrow insertion grooves 15 that penetrate in the thickness direction and are provided in the wooden pattern plywood 3. The insertion grooves 15 are formed by irradiating the wooden pattern plywood 3 with a laser beam output from a laser processing machine so as to correspond to the shape and folds of the blank.

[0031] <Plywood for wooden patterns> Figure 3 is a cross-sectional view of a wooden pattern plywood 3 before the formation of the insertion grooves according to one embodiment of the present invention. The wooden pattern plywood 3 comprises a plywood body 21 having a surface on one side (upper side) and the other side (lower side), a covering plate 23 arranged to cover each surface of the plywood body 21, and a coating layer 25 arranged to cover the surface of each covering plate 23.

[0032] <Plywood body> As the plywood body 21, for example, a laminated structural board can be used, which is made by overlapping and bonding multiple veneers (plywood) cut from raw logs using a rotary lathe or the like so that the wood grains are alternately perpendicular to each other, or a medium-density fiberboard (MDF) made from wood fibers obtained from plantation trees that can be produced on a planned basis, with a synthetic resin used as an adhesive added, and then hot-pressed into a board shape.

[0033] <cut> The plywood body 21 has required notches 30 to cut the wood fibers. The notches 30 are made to a depth of about 60-70% of the thickness direction of the plywood body 21, with the aim of preventing warping and twisting and manufacturing highly accurate plywood 3 for wooden patterns. The notches 30 are formed, for example, by using a special cutting tool with a panel processing device described in Japanese Patent Application Publication No. 2014-218034 (Patent Document 1) to cut diagonally with respect to the thickness direction of the plywood body 21 from the upper side surface to the lower side surface of the plywood body 21. In this way, the notches 30 are formed to cut diagonally at a predetermined angle with respect to the thickness direction of the plywood body 21.

[0034] Figure 4 is an enlarged cross-sectional view of the main part of the wooden pattern plywood 3 including the notch 30. As shown in Figure 4(a), in the portion of the plywood body 21 including the notch 30, the gap in the notch 30 is relatively large in the shallow part of the notch 30 (shallow part 30a), and as the depth of the notch increases, the gap in the notch 30 becomes smaller. In the deepest part of the notch 30 (deep part 30b) and its vicinity, the wood fibers are cut, but the elasticity of the wood fibers causes the parts of the plywood body 21 on both sides of the notch 30 to remain in contact.

[0035] <Covering plate> As the covering plate 23, a relatively thin laminated structure plate can be used, which is made by overlapping and bonding at least two veneers having fiber orientation so that their fiber directions are perpendicular to each other. The covering plate 23 is bonded to each surface of the plywood body 21 using adhesive.

[0036] <Coating layer> The coating layer 25 is formed by applying a paint containing at least one of known antiviral agents, antibacterial agents, insecticides, and fungicides to the surface of each covering plate 23, and has at least one of the antiviral, antibacterial, insecticide, and fungicide effects. The coating layer 25 is not particularly limited and can cover the covering plate 23 in a way that suppresses the evaporation of moisture from the covering plate 23. For example, in addition to forming the coating layer 25 by applying paint to the surface of the covering plate 23, the coating layer 25 may also be formed by adhering polyester resin or the like to the surface of the covering plate 23, or by attaching water-repellent paper, resin-impregnated paper, resin film, or other film that can suppress moisture evaporation to the surface of the covering plate 23.

[0037] In the wooden pattern plywood 3 with the above configuration, as shown in Figure 4(a), a coating layer 25 is formed to cover the covering plate 23. Therefore, evaporation of moisture from the plate surface covered by the coating layer 25 (coated side plate surface 23a) of the covering plate 23 is considerably suppressed. On the other hand, the plate surface of the covering plate 23 that is bonded to the plywood body 21 (uncoated side plate surface 23b) has an adhesive layer (not shown) formed between it and the plywood body 21 by the application of adhesive, but it is not completely coated by the adhesive layer. In addition, the plywood body 21 has a larger thickness than the covering plate 23, and the area of ​​the outer surface that comes into contact with the outside air is larger. For these reasons, evaporation of moisture from the uncoated side plate surface 23b of the covering plate 23 cannot be suppressed very well. Consequently, in the covering plate 23, evaporation of moisture progresses relatively more on the uncoated side plate surface 23b than on the coated side plate surface 23a, and the shrinkage effect on the uncoated side plate surface 23b progresses more than on the coated side plate surface 23a. As a result, a force causes the covering plate 23 to warp in a convex shape towards the coated side surface 23a, resulting in residual tensile stress in the thickness direction and residual compressive stress along the surface of the plywood body 21. The portion of the plywood body 21 including the cut 30 is where the cross-sectional shape changes abruptly. In the shallow part 30a of the cut 30, the gap in the cut 30 is relatively large, and as the depth of the cut 30 increases, the gap in the cut 30 becomes smaller. In the deep part 30b of the cut 30 and its vicinity, the wood fibers are divided, but due to the elasticity of the wood fibers, the parts of the plywood body 21 on both sides of the cut 30 remain in contact. Of the tensile and compressive stresses remaining inside the plywood body 21, the compressive stress does not act on the shallow part 30a of the notch 30 and its vicinity, where the gap is relatively large. Instead, it is concentrated in the deep part 30b of the notch 30 and its vicinity, where the parts of the plywood body 21 on both sides of the notch 30 are in contact (indicated by the arrow with the symbol "σ" in Figure 4(a)). As a result, the parts of the plywood body 21 on both sides of the notch 30 in the deep part 30b and its vicinity are tightly packed together, and the density of this tightly packed part increases relatively compared to the surrounding density.In the portion of the wooden pattern plywood 3 that includes the notch 30, although the density decreases due to the gap that inevitably arises as a result of providing the notch 30, the density increases in the deeper part 30b of the notch 30 and its vicinity. As a result, the decrease in density throughout the depth direction of the portion of the wooden pattern plywood 3 that includes the notch 30 can be suppressed. In this way, the decrease in density of the portion including the notch 30, which is provided to prevent warping and twisting, can be suppressed, and thus burn damage during thermal cutting by the laser beam when the laser beam is irradiated onto that portion can be suppressed.

[0038] In the wooden pattern plywood 3, the notch 30 is formed by cutting diagonally with respect to the thickness direction of the plywood body 21, so that the notch 30 and the insertion groove 15 intersect in the wooden pattern plywood 3. For this reason, as shown in Figure 4(b), although the part of the plywood body 21 around the area corresponding to the gap of the notch 30 (indicated by the arrow with the symbol "A" in Figure 4(b)) does not function to hold the processing blade 5, the part of the plywood body 21 other than the area where the notch 30 and the insertion groove 15 intersect functions to hold the processing blade 5, thus preventing a decrease in the holding force of the processing blade 5.

[0039] In the plywood 3 for wooden patterns, the coating layer 25 provides at least one of the following effects: antiviral, antibacterial, insecticidal, and antifungal properties, which prevents viruses, bacteria, pests, and mold from growing on the plywood itself. This ensures that the hygienic environment of production sites such as die-cutting, as well as the blanks (products) of paper containers and other materials produced, remains clean.

[0040] <First method for manufacturing plywood for wooden patterns> Figure 5 is an explanatory diagram of the first manufacturing method of the wooden pattern plywood 3. The wooden pattern plywood 3 can be manufactured by performing the following covering plate bonding step and coating layer formation step.

[0041] <Cover board adhesion process> As shown in Figures 5(a) and 5(b), in the covering plate bonding process, the covering plates 23 are bonded to each surface of the plywood body 21 using adhesive. At this time, since no coating layer 25 is formed on any of the surfaces of the covering plates 23 being bonded, moisture evaporation proceeds to the same extent on each surface of the covering plate 23, and no warping occurs on any side of the covering plate 23, resulting in a flat covering plate 23 being bonded to each surface of the plywood body 21. In this way, each surface of the plywood body 21, including the cutouts 30, is covered by the covering plates 23.

[0042] <Coating layer formation process> As shown in Figures 5(b) to (c), in the coating layer formation process, a coating layer 25 is formed so as to cover the surface of each covering plate 23 by applying a paint containing an antiviral agent or the like to the outer surface of each covering plate 23.

[0043] In the covering plate 23 of the wooden pattern plywood 3 manufactured by the first manufacturing method described above, the side of the plate covered by the coating layer 25 (coated side plate surface 23a) is prevented from contact with the outside air by the coating layer 25, so the evaporation of moisture from the coated side plate surface 23a is considerably suppressed. On the other hand, in the covering plate 23, the side of the plate that is bonded to the plywood body 21 (uncoated side plate surface 23b) has an adhesive layer (not shown) interposed between it and the plywood body 21 by the application of adhesive, but it is not completely coated by the adhesive layer. Also, the plywood body 21 has a larger thickness than the covering plate 23, and the area of ​​the outer surface that comes into contact with the outside air is larger. The uncoated side plate surface 23b of the covering plate 23 is in communication with the outside through the adhesive layer (not shown) interposed between it and the plywood body 21, and through the plywood body 21, so the evaporation of moisture from the uncoated side plate surface 23b cannot be suppressed very well. Therefore, in the covering plate 23, moisture evaporation proceeds relatively more on the uncoated side plate 23b than on the coated side plate 23a, and shrinkage proceeds more on the uncoated side plate 23b than on the coated side plate 23a. As a result, the covering plate 23 attempts to warp in a way that causes a convex shape on the coated side plate 23a side, but because the covering plate 23 is bonded to the plywood body 21, it cannot warp, and the compressive stress caused by the force that would have caused the warp remains inside the plywood body 21. The portions of the plywood body 21 on both sides of the cut 30 in the deep part 30b of the cut 30 are tightly bonded due to the action of the compressive stress remaining inside the plywood body 21, and the density of this bonded portion increases relatively to the density of the surrounding area. As a result, the decrease in the overall density in the depth direction of the portion of the wooden pattern plywood 3 including the cut 30 can be suppressed. In this way, the decrease in density in the portion including the notch 30, which is provided to prevent warping and twisting, can be suppressed, and thus burn damage during thermal cutting by the laser beam when the laser beam is irradiated onto that portion can be suppressed.

[0044] <Second method of manufacturing plywood for wooden patterns> Figure 6 is an explanatory diagram of the second manufacturing method of the wooden pattern plywood 3. The wooden pattern plywood 3 can be manufactured by performing the following coating layer formation step and covering plate bonding step.

[0045] <Coating layer formation process> As shown in Figure 6(a), in the coating layer formation process, a paint containing an antiviral agent or the like is applied only to one side of the coated plate 23. This forms a coating layer 25 that covers only one side of the coated plate 23.

[0046] When the coating layer 25 is formed to cover only one side of the covering plate 23, the evaporation of moisture from the side covered by the coating layer 25 (coated side plate surface 23a) is considerably suppressed because the coating layer 25 prevents contact with the outside air. On the other hand, the side of the plate that is bonded to the plywood body 21 (uncoated side plate surface 23b) is in contact with the outside air, so the evaporation of moisture from the uncoated side plate surface 23b cannot be suppressed. As a result, in the covering plate 23, the evaporation of moisture progresses relatively more on the uncoated side plate surface 23b than on the coated side plate surface 23a, and the shrinkage effect on the uncoated side plate surface 23b progresses more than on the coated side plate surface 23a. This causes a warp in the covering plate 23 that is convex on the coated side plate surface 23a side (shown as an upward convex and downward convex in Figure 6(a)).

[0047] <Cover board adhesion process> As shown in Figures 6(b) to (c), in the covering plate bonding process, the uncoated side surface 23b of each covering plate 23, which has warped due to the formation of the coating layer 25, is placed facing each surface of the plywood body 21, and with an adhesive (not shown) interposed between the plywood body 21 and each covering plate 23, the plywood body 21 and each covering plate 23 are pressed together using a bonding press machine to form a single unit. In this way, each surface of the plywood body 21, including the cutouts 30, is covered by the covering plate 23, and each covering plate 23 is bonded to the plywood body 21 in a manner that eliminates the warping caused by the formation of the coating layer 25.

[0048] In the second manufacturing method described above, the force applied to the covering plate 23 to eliminate the warping that occurred in the covering plate 23 by forming the coating layer 25 results in compressive stress remaining inside the plywood body 21 as the covering plate 23 is bonded to the plywood body 21. Thus, the compressive stress generated in the second manufacturing method is due to the force applied to the covering plate 23 to eliminate the warping that occurred in the covering plate 23. In contrast, the compressive stress generated in the first manufacturing method described above is due to the force that attempts to cause warping in the covering plate 23 after it has been bonded to the plywood body 21, where forming the coating layer 25 would cause a convex shape on the coated side surface 23a, but the covering plate 23 cannot warp because it is bonded to the plywood body 21, and the force that attempts to cause warping is due to this. For this reason, the compressive stress generated in the second manufacturing method is greater than the compressive stress generated in the first manufacturing method. Consequently, the portions of the plywood body 21 on both sides of the cut 30 in the deep part 30b of the cut 30 and its vicinity can be bonded more strongly. This makes it possible to more effectively suppress the decrease in density in the part of the wooden plywood 3 that includes the cut 30, and to reliably suppress burn damage during thermal cutting with a laser beam.

[0049] Although the wooden plywood and the method for manufacturing wooden plywood of the present invention have been described above based on one embodiment, the present invention is not limited to the configuration described in the above embodiment, and its configuration can be modified as appropriate without departing from the spirit of the invention.

[0050] (Another Embodiment 1) Figure 7 is a cross-sectional view of the wooden pattern plywood 3 according to another embodiment 1 before the insertion groove is formed. Figure 7(a) is an example in which diagonal cuts 30 are provided on both surfaces of the plywood body 21, Figure 7(b) is an example in which straight cuts 30' are provided on one surface of the plywood body 21, and Figure 7(c) is an example in which straight cuts 30' are provided on both surfaces of the plywood body 21.

[0051] In the above embodiment, an example was shown in which the notches 30 are formed by cutting diagonally from the upper surface to the lower surface of the plywood body 21 using a special cutting tool, but the invention is not limited to this. As shown in Figure 7(a), diagonal notches 30 that form a predetermined angle with respect to the thickness direction of the plywood body 21 may be provided on both sides of the plywood body 21 by cutting diagonally from both the upper and lower surfaces of the plywood body 21 alternately at appropriate intervals. Alternatively, instead of diagonal notches 30, notches 30' that extend straight in the thickness direction of the plywood body 21 may be provided on one side of the board surface (see Figure 7(b)), or on both sides (see Figure 7(c)).

[0052] (Another Embodiment 2) Figure 8 is a plan view of the plywood body 21 that constitutes the wooden pattern plywood 3 according to another embodiment 2. As shown in Figure 8, the wooden pattern plywood 3 may be constructed using a plywood body 21 in which notches 30(30') are formed diagonally on the long side 21a and short side 21b of the plywood body 21. According to the wooden pattern plywood 3 of another embodiment 2, since notches 30(30') are formed diagonally on the long side 21a and short side 21b of the plywood body 21, the insertion groove 15 (see Figure 2), which is often formed parallel to the long side 21a and short side 21b, and the notches 30(30') intersect. Therefore, in the wooden pattern plywood 3, the portion of the plywood body 21 other than the intersection of the notches 30(30') and the insertion groove 15 functions to hold the processing blade 5, thus suppressing a decrease in the holding force of the processing blade 5.

[0053] (Another embodiment 3) Figure 9 is a perspective view illustrating the structure of the plywood body 21 constituting the wooden pattern plywood 3 according to the other embodiment 3. In the above embodiment, an example of constructing the wooden pattern plywood 3 was shown using a plywood body 21 in which notches 30 are formed on a laminated structure board made by overlapping and bonding a plurality of veneers having fiber orientation so that their fiber directions are perpendicular to each other. However, the invention is not limited to this. As shown in Figure 9, there is also an example of constructing the wooden pattern plywood 3 using a plywood body 21 in which veneers 40 having a number of perforated notches 35 that divide the wood fibers are overlapped and bonded so that their fiber directions are perpendicular to each other. According to the wooden pattern plywood 3 of the other embodiment 3, warping and twisting of each veneer 40 are prevented by the notches 35 formed on each veneer 40, so that warping and twisting of the plywood body 21, which is made up of multiple laminated veneers 40, can be prevented more effectively. Also, similar to the above embodiment, it is possible to suppress the decrease in density of the entire depth direction of the portion of the wooden pattern plywood 3 that includes the notches 35. Therefore, the same effects as in the above embodiment can be obtained. [Industrial applicability]

[0054] The plywood for wooden patterns and the method for manufacturing the plywood for wooden patterns of the present invention can be used as a base material for wooden patterns used in the process of manufacturing blanks for paper containers, etc., and can also be used as a base material for wooden patterns used to punch out various sheet materials such as synthetic resin sheets, cloth, and leather into desired shapes. [Explanation of symbols]

[0055] 1 Wooden mold 3. Plywood for wooden patterns 5 Processing blade 21 Plywood body 23 Covering plate 25 Coating layer 30 cuts 35 cuts 40 Solid wood

Claims

1. A wooden plywood used as a base material for a wooden mold in which a processing blade is embedded, A plywood body having cuts that divide the wood fibers, A covering plate is adhered to the plywood body so as to cover the aforementioned cutout, A coating layer formed to cover the aforementioned covering plate, Equipped with, A wooden pattern plywood in which, due to a force that suppresses the evaporation of moisture from the coated side surface of the covering plate on the side covered by the coating layer, causing the covering plate to warp in such a way that it becomes convex towards the coated side surface, compressive stress remains inside the plywood body in the direction along the surface of the plywood body.

2. The plywood for wooden molds according to claim 1, wherein the plywood body portions on both sides of the cut are in close contact with the deepest part of the cut and in its vicinity.

3. The plywood for wooden molds according to claim 1 or 2, wherein the notch is formed to be cut diagonally with respect to the thickness direction of the plywood body.

4. The plywood for wooden molds according to claim 1 or 2, wherein the notches are formed diagonally with respect to at least one side of the plywood body.

5. The plywood body is constructed by laminating a plurality of veneers in which the notches are formed, as described in claim 1 or 2.

6. The plywood for wooden molds according to claim 1 or 2, wherein the coating layer has at least one of the following effects: antiviral effect, antibacterial effect, insecticidal effect, and antifungal effect.

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