Wood composite material, flooring material, method for manufacturing wood composite material, and method for manufacturing flooring material

Abstract

To provide a wooden composite material, a flooring material, and a method for manufacturing the same, capable of suppressing warping caused by dimensional change due to humidity change and the like, and sufficiently ensuring scratch resistance with excellent design.SOLUTION: A floor material 1 includes a wooden composite material 2 and a coating film 3. The wooden composite material 2 includes a wooden base material 10, a first wooden fiber board 11 bonded to the surface of the wooden base material 10, a second wooden fiber board 12 adhered to the surface of the first wooden fiber board 11, a decorative material 13 adhered to the surface of the second wooden fiber board 12, and grooves 14 formed in the decorative material 13 and the second wooden fiber board 12. The second wooden fiber board 12 is softwood MDF.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wood composite, a flooring material, a method for manufacturing a wood composite, and a method for manufacturing a flooring material. [Background technology]

[0002] Flooring materials used in detached houses, apartment buildings, and other buildings include solid wood flooring, as well as decorative flooring made from the surface of wood substrates such as plywood, MDF, and particle board, or laminated wood substrates (hereinafter, laminated wood substrates will also be referred to simply as "wood substrates") with a decorative material made of fine wood applied to the surface.

[0003] Decorative flooring materials use a base material that expands and contracts less due to moisture than solid wood, and the surface is coated with various types of paint to prevent moisture from penetrating inside. As a result, they are less likely to warp and are easier to handle in the environment in which they are used after installation, and for these reasons, they are becoming more widely used on construction sites.

[0004] Flooring, a type of composite material, has a decorative panel placed on the surface (top surface) of a wood substrate, with grooves such as V-shaped grooves formed in the decorative panel to enhance the design. The surface of the flooring is then finished with a coating to ensure abrasion resistance, scratch resistance, and smoothness, and to prevent cleaning cloth fibers from remaining in the grooves. The finishing coat is applied using colorless paint or colored paint, and the flooring surface, including the grooves, is made up of a coating film.

[0005] In order to effectively utilize wood substrates with defective surface quality, such as coniferous plywood and wood substrates made from planted trees, composite materials are used in which wood fiber boards are combined with the surface of the wood substrate (see, for example, Patent Documents 1 to 4). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 5909087 specification [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-50896 [Patent Document 3] Patent No. 5820994 specification [Patent Document 4] Japanese Utility Model Application Publication No. 6-16004 Summary of the Invention [Problem to be solved by the invention]

[0007] In the configuration described in Patent Document 1, the wood fiberboard directly beneath the decorative surface layer of the flooring is made of hardwood fiber. Because hardwood fiberboards are dark in color, if the decorative surface layer is light in color, the underlying hardwood fiberboard will show through the decorative surface layer, resulting in the color of the underlying board showing through. This show-through of the underlying board color marshalling the light color of the decorative surface layer and reducing the design appeal. However, simply replacing hardwood fiberboards with softwood fiberboards results in significant dimensional change of the softwood fiberboard in response to humidity changes. This results in significant dimensional change of the flooring due to moisture from the concrete foundation and humidity changes when underfloor heating is in use or not, leading to significant warping of the flooring.

[0008] In the configuration described in Patent Document 2, a surface decorative material is laminated on a wooden substrate, and grooves are formed across the surface decorative material and the wooden substrate. A primer containing a scale-like pigment is applied to the inner surface of the grooves, preventing excessive absorption of the colored paint into the wooden substrate in the grooves. However, since penetration of the colored paint into the grooves is prevented, there is a risk of paint pooling in the grooves. This paint pooling in the grooves reduces the design quality.

[0009] The wood board described in Patent Document 3 has a structure in which a wood-based thermoplastic resin sheet containing wood flour and inorganic filler is bonded to the surface of a wood-based substrate, and a decorative layer is further provided on the surface. Joint grooves are formed in the decorative layer and the wood-based thermoplastic resin sheet, and the surface of the wood board, including the joint grooves, is covered with a surface protective coating. Even with this structure, as with the structure described in Patent Document 2, the penetration of colored paint into the grooves is suppressed, so there is a risk of paint pooling in the grooves. Paint pooling in the grooves reduces the design.

[0010] The veneer-laminated decorative board described in Patent Document 4 has a configuration in which a veneer dyed in a similar color to the thin veneer is interposed between the thin veneer placed on the front side of the decorative board and the wood substrate placed on the back side of the decorative board. However, with this configuration, it is difficult to ensure sufficient strength for the veneer, and it is difficult to ensure sufficient scratch resistance, such as resistance to dents when a heavy object is dropped.

[0011] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a wood composite material, a flooring material, and a manufacturing method thereof that can suppress warping caused by dimensional changes due to humidity changes, etc., have excellent design properties, and can ensure sufficient scratch resistance. [Means for solving the problem]

[0012] The present invention relates to the following wood composite material, flooring material, and manufacturing methods thereof.

[0013] (1) a wood substrate; a first wood fiber board adhered to the surface of the wood substrate; a second wood fiber board adhered to the surface of the first wood fiber board; a decorative material adhered to the surface of the second wood fiber board; Grooves formed in the decorative material and the second wood fiber board; Equipped with The second wood fiberboard is a softwood MDF, a wood composite.

[0014] (2) The wood composite material according to (1), wherein the first wood fiber board is hardwood MDF.

[0015] (3) The density of the softwood MDF is 0.70 g / cm 3 The density of the hardwood MDF is 0.70 g / cm or more. 3 The wood composite material according to (2) above, which satisfies at least one of the above requirements.

[0016] (4) The wood composite material according to any one of (1) to (3), wherein the second wood fiber board is thinner than the first wood fiber board.

[0017] (5) The composite wood material according to any one of (1) to (4), wherein the decorative material is a light-colored board.

[0018] (6) The wood composite material according to any one of (1) to (5), wherein the wood substrate includes a softwood layer.

[0019] (7) The composite wood material according to any one of (1) to (6), a coating film formed on the surface of the decorative material and the surface of the groove portion; The flooring is provided with:

[0020] (8) a wood substrate; a first wood fiber board adhered to the surface of the wood substrate; a second wood fiber board adhered to the surface of the first wood fiber board; a decorative material adhered to the surface of the second wood fiber board; Grooves formed in the decorative material and the second wood fiber board; Equipped with A method for producing a wood composite material, wherein the second wood fiber board is softwood MDF, A method for manufacturing a wood composite material, comprising the steps of: preparing the wood base material, the first wood fiber board, the second wood fiber board, and the decorative material separately; and then stacking the wood base material, the first wood fiber board, the second wood fiber board, and the decorative material together.

[0021] (9) Dividing the first wood fiber board along the board surface direction at multiple positions in the thickness direction of the first wood fiber board to form multiple first divided boards; The method for manufacturing a wood composite material according to (8) above, wherein any one of the plurality of first divided boards is the first wood fiber board.

[0022] (10) Dividing the second material wood fiber board along the board surface direction at multiple positions in the thickness direction of the second material wood fiber board to form multiple second divided boards; The method for producing a wood composite material according to (8) or (9), wherein any one of the plurality of second divided plates is the second wood fiber plate.

[0023] (11) The method for manufacturing a wood composite material according to (10), wherein the divided boards that become the wood fiber boards contain a relatively dense rock layer in the raw wood fiber board.

[0024] (12) The method for manufacturing a wood composite material described in (11) above, in which the divided boards that become the wood fiber boards are arranged with the rock layer facing the decorative material side.

[0025] (13) A step of forming grooves in the decorative material and the second wood fiber board of the wood composite material according to any one of (8) to (12); a coating step of coating the wood composite material in which the grooves are formed; A method for manufacturing a flooring material, comprising: [Effects of the Invention]

[0026] According to the present invention, it is possible to provide a wood composite material that can suppress warping caused by dimensional changes due to changes in humidity, has excellent design properties, and ensures sufficient scratch resistance. [Brief explanation of the drawings]

[0027] [Figure 1]Fig. 1(A) is a cross-sectional view of a flooring material including a wood composite material according to this embodiment, showing the state of the flooring material cut at a cross section perpendicular to the longitudinal direction. Fig. 1(B) is an enlarged view of a portion of Fig. 1(A). [Figure 2] 2(A) and 2(B) are schematic diagrams showing the main steps of preparing a first wood fiber board and a second wood fiber board in the (A1) preparation step, respectively. [Figure 3] FIG. 3 is a schematic diagram showing the (A2) bonding step. [Figure 4] FIG. 4(A) is a schematic diagram showing the (A3) groove forming step, and FIG. 4(B) is a schematic diagram showing the (A4) painting step. DETAILED DESCRIPTION OF THE INVENTION

[0028] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0029] FIG. 1(A) is a cross-sectional view of a flooring material 1 including a wood composite material 2 according to this embodiment, showing the state of the flooring material 1 cut at a cross section perpendicular to the longitudinal direction. FIG. 1(B) is an enlarged view of a portion of FIG. 1(A). FIGS. 2(A) and 2(B) are schematic diagrams showing the main steps of preparing a first wood fiber board and a second wood fiber board in the (A1) preparation step. FIG. 3 is a schematic diagram showing the (A2) bonding step. FIG. 4(A) is a schematic diagram showing the (A3) groove forming step. FIG. 4(B) is a schematic diagram showing the (A4) painting step.

[0030] 1. Wood composite material according to this embodiment Referring to Figures 1(A) and 1(B), the flooring material 1 according to this embodiment has a total thickness of approximately 12.0 mm. There are no particular restrictions on the width or length of the flooring material 1. Typically, the width is 150, 300, or 303 mm, and the length is 900, 1800, or 1818 mm. A thin thickness is preferable from the standpoint of workability (e.g., because it is easy to cut and there is little waste material), but from the standpoint of rigidity, a thickness of 5.0 mm or more is preferable, and 6.0 mm or more is more preferable. The flooring material 1 is installed on a base board or a heated floor mat for underfloor heating. Hereinafter, when the flooring material 1 is installed in a building, the surface of the flooring material 1 facing the member on which the flooring material 1 will be placed is referred to as the back surface, and the surface facing the ceiling of the building is referred to as the front surface.

[0031] The flooring material 1 has a wood composite material 2 and a coating film 3.

[0032] The wood composite material 2 has a wood base material 10, a first wood fiber board 11 adhered to the surface of the wood base material 10, a second wood fiber board 12 adhered to the surface of the first wood fiber board 11, a decorative material 13 adhered to the surface of the second wood fiber board 12, and grooves 14 formed in the decorative material 13 and the second wood fiber board 12.

[0033] There are no particular restrictions on the structure of the wood substrate 10. Examples of wood substrate 10 include plywood, LVL (laminated veneer lumber), particle board, and OSB (oriented strand board). The material of the wood substrate is not particularly limited, but examples include softwood plywood, plywood made from fast-growing trees such as planted trees, hardwood plywood, and plywood made from a combination of multiple of these wood materials.

[0034] Examples of the softwood plywood include larch, todomatsu, hinoki, cedar, spruce, Japanese spruce, red pine, Douglas fir, western hemlock, spruce, and radiata pine, and also include plywood made from one or more selected species of these. Examples of fast-growing tree plywood, such as plantation trees, include falcata, eucalyptus, acacia mangium, japonica, samosa, and poplar, and also include plywood made from one or more selected species of these. Examples of hardwood plywood include tropical woods such as meranti, and fast-growing tree plywood such as lauan plywood and falcata plywood.

[0035] In this embodiment, the wood substrate 10 is a laminated board made of multiple laminated veneers, such as a 5-ply softwood plywood. For example, the first, third, and fifth layers are made of Abies sachalinensis, and the second and fourth layers are made of cedar. For the first and fifth layers (back boards), it is particularly advisable to select a wood species with a relatively higher specific gravity than the second and fourth layers (core boards). This is because wood species with a higher specific gravity tend to have higher strength and better surface properties, while wood species with a lower specific gravity tend to have lower strength and more defects such as knots. This laminated board may also be a plywood in which the first, third, and fifth layers are made of Meranti wood and the second and fourth layers are made of Falcata wood. The wood species may be selected appropriately depending on the performance required of the substrate.

[0036] The thickness of each of the first, third, and fifth layers can be 1.0 mm or more, 1.2 mm or more, 1.4 mm or more, 1.6 mm or more, or 1.7 mm or more. The thickness of each of the second and fourth layers can be 2.0 mm or more, 2.2 mm or more, 2.4 mm or more, or 2.6 mm or more. Preferably, the second and fourth layers are made of the same wood species and have the same thickness. The thickness of each layer can be selected appropriately depending on the performance required of the substrate.

[0037] The number of plies in the laminated board that constitutes the wood base material 10 may be 3, 7, or more than 7. The laminated board may also be plywood made of a mixture of wood species depending on the required performance.

[0038] The thickness of the wood substrate 10 is not particularly limited, but can be, for example, 8.0 to 12.0 mm. In particular, to ensure sufficient strength, a thickness of 9.0 mm or more is preferable, for example, about 10 mm. The bending Young's modulus of the wood substrate 10 in the width direction is preferably 3.0 GPa or more.

[0039] A backing material may be attached to the back surface of the wood substrate 10. Examples of backing materials include veneer, paper, resin film, resin-laminated paper, and polysand paper, which is a resin composite with paper on both sides. In order to prevent water vapor from entering the flooring material 1, the backing material should have a water vapor permeability of 5 g / (m2) or less as measured by JIS K 7129B (infrared sensor). 2 ·d) or less, and 2 ·d) or less is more preferable. When the backing material is sliced ​​veneer, the thickness is preferably 0.1 mm to 0.4 mm. When the backing material is paper or film, the thickness is preferably 5 μm to 100 μm.

[0040] The first wood fiber board 11 is not particularly limited as long as it is a wood fiber board. Examples of the first wood fiber board 11 include MDF (Medium Density Fiberboard), HB (Hardboard), and insulation board. Examples of MDF include softwood MDF and hardwood MDF. Examples of these softwoods and hardwoods include the above-mentioned tree species. It is preferable that the first wood fiber board 11 is made of hardwood MDF, which has excellent hardness and little dimensional change due to humidity changes. The density of hardwood MDF is 0.70 g / cm3 from the viewpoint of ensuring sufficient scratch resistance when a heavy object is dropped. 3 The above is preferable.

[0041] The hardwood MDF is a dark-colored MDF primarily made of hardwood. The thickness of the hardwood MDF constituting the first wood fiber board 11 is preferably 0.7 mm to 2.7 mm. By making the hardwood MDF 0.7 mm or thicker, the strength (hardness) of the hardwood MDF can be sufficiently ensured. This allows the hardwood MDF to effectively absorb the irregularities of the wood base material 10, more reliably preventing the irregularities of the wood base material 10 from rising up onto the decorative material 13. By making the hardwood MDF 2.7 mm or thinner, the dimensional change of the first wood fiber board 11 due to humidity is prevented from becoming too large, more reliably preventing warping of the flooring material 1. Examples of lower limits for the thickness of the hardwood MDF include 0.7 mm, 1.0 mm, and 1.1 mm. Examples of upper limits for the thickness of hardwood MDF include 2.7 mm, 2.2 mm, 1.7 mm, 1.5 mm, 1.4 mm, and 1.3 mm.

[0042] 1(B) and 2(B), the first wood fiber board 11 can be obtained by, for example, dividing a first material wood fiber board 21 (MDF), which is the material for the first wood fiber board 11, in half thicknesswise using a slicer or the like, and then polishing one of the resulting two first divided boards 31 to a predetermined thickness using a sander or the like. Dividing the MDF into the first wood fiber board 11 eliminates the need to adjust the thickness of the MDF (first material wood fiber board 21) to match the thickness of the first wood fiber board 11. Furthermore, polishing reduces variations in the thickness of the board surface. Furthermore, from the perspective of ensuring the strength of the first wood fiber board 11, it is preferable that the first divided board 31 used as the first wood fiber board 11 be either the top or bottom surface of the MDF in the first material wood fiber board 21, including the high-density rock layers on both sides. Furthermore, the first divided board 31 used as the first wood fiber board 11 is preferably arranged with the cut surface of the first material wood fiber board 21 facing the wood base material 10 (with the rock layer facing the decorative material 13). This allows the high-strength rock layer to absorb impacts from the decorative material 13, further improving the scratch resistance (i.e., the resistance to dents) of the flooring material 1. Note that the number of divisions into which the first material wood fiber board 21 is divided when forming the first wood fiber board 11 may be more than two. Alternatively, the first material wood fiber board 21 may be used as the first wood fiber board 11 without being divided. The thickness of the first material wood fiber board 21 is not limited.

[0043] The second wood fiber board 12 is made of softwood MDF. Examples of softwood include the above-mentioned tree species. The density of softwood MDF is 0.70 g / cm3 from the viewpoint of ensuring sufficient damage resistance when a heavy object is dropped. 3 More than 0.80 g / cm is preferable. 3 More preferably, 0.85 g / cm or more is more preferable, and even more preferably 0.85 g / cm 3 That's all. The surface density of the part of the second wood fiber board 12 where the grooves 14 are machined affects the paint absorption. If the density is too high, the paint absorption will be poor and there is a risk of paint pooling in the grooves 14. From the viewpoint of paint absorption, the surface density of softwood MDF is 1.1 g / cm 3 The following is preferred:

[0044] In this specification, for both softwood MDF and hardwood MDF, a density of 0.85 g / cm 3 Higher density materials than these are also included in MDF.

[0045] The softwood MDF is a light-colored MDF primarily made of softwood. The thickness of the softwood MDF constituting the second wood fiber board 12 is preferably 0.3 mm to 1.0 mm. A softwood MDF thickness of 0.3 mm or more ensures scratch resistance, such as dents caused by a heavy object being dropped. Furthermore, a softwood MDF thickness of 1.0 mm or less prevents excessive dimensional changes in the second wood fiber board 12 due to humidity changes, thereby more reliably preventing warping of the flooring material 1. Furthermore, while wood fiber boards are more susceptible to paint penetration than decorative materials such as veneers, a softwood MDF thickness of 1.0 mm or less can prevent excessive paint penetration in the grooves 14, preventing the formation of a coating film 3 on the surface of the second wood fiber board 12. This allows the coating film 3 to be more uniformly formed on the surfaces of the second wood fiber board 12 and the decorative material 13 in the grooves 14. The lower limit of the thickness of the softwood MDF can be 0.3 mm or 0.4 mm, and the upper limit of the thickness of the softwood MDF can be 1.0 mm, 0.7 mm, or 0.6 mm.

[0046] 1(B) and 2(A), the second wood fiber board 12 can be obtained by, for example, dividing a second material wood fiber board 22 (MDF), which is the material for the second wood fiber board 12, into four pieces in the thickness direction using a slicer or the like, and then grinding one of the four second divided boards 32 to a predetermined thickness using a sander or the like. Dividing MDF into the second wood fiber board 12 eliminates the need to adjust the thickness of the MDF (second material wood fiber board 22) to match the thickness of the second wood fiber board 12. Grinding reduces thickness variations across the board surface. Furthermore, from the perspective of ensuring the strength of the second wood fiber board 12, it is preferable that the second divided boards 32 used as the second wood fiber board 12 be either the top or bottom surface of the softwood MDF in the second material wood fiber board 22, including the high-density rock layers on both sides. Furthermore, the second divided board 32 used as the second wood fiber board 12 is preferably arranged with the cut surface of the second material wood fiber board 22 facing the wood base material 10 (with the rock layer facing the decorative material 13). This allows the high-strength rock layer to absorb impacts from the decorative material 13, further improving the scratch resistance (i.e., the resistance to dents) of the flooring material 1. The number of divisions of the second material wood fiber board 22 when forming the second wood fiber board 12 may be two, three, or more than four. The thickness of the second material wood fiber board 22 is not limited.

[0047] In this embodiment, the second wood fiber board 12 is thinner than the first wood fiber board 11. This prevents the second wood fiber board 12 from becoming excessively thick. As a result, the paint used to form the coating film 3 is prevented from excessively seeping into the second wood fiber board 12 in the grooves 14, making the finish (appearance) of the coating film 3 more uniform in the grooves 14 and the decorative material 13. Furthermore, dimensional change in the second wood fiber board 12, which is made of MDF containing softwood, which is subject to greater dimensional change due to humidity changes than hardwood, can be reduced. This more reliably prevents warping of the flooring material 1.

[0048] The combined thickness of the first and second wood fiber boards 11 and 12 (total thickness) is preferably 1.0 mm to 3.0 mm. By making the combined thickness of the wood fiber boards 11 and 12 1.0 mm or more, the strength of the wood fiber boards 11 and 12 can be ensured. This allows the wood fiber boards 11 and 12, particularly the first wood fiber board 11, to effectively absorb irregularities in the wood base material 10, more reliably preventing the irregularities in the wood base material 10 from rising up onto the decorative material 13. Furthermore, by making the combined thickness of the wood fiber boards 11 and 12 3.0 mm or less, dimensional changes in the wood fiber boards 11 and 12, particularly the second wood fiber board 12, due to humidity are prevented from becoming too large, more reliably preventing warping of the flooring material 1. Examples of lower limits for the combined thickness of the wood fiber boards 11 and 12 include 1.0 mm, 1.2 mm, 1.5 mm, and 1.6 mm. The upper limit of the total thickness of the wood fiber boards 11, 12 can be exemplified as 3.0 mm, 2.5 mm, 2.2 mm, 1.9 mm, and 1.8 mm.

[0049] The decorative material 13 can be made of processed wood such as veneer or sawn board, or a decorative sheet with a colored pattern printed on a sheet such as a resin film or paper. The thickness of the decorative material 13 is generally 0.05 mm to 3.0 mm, but is not limited to this thickness. When attaching the wooden decorative material 13 by hot pressing (hot pressing), the thickness of the decorative material 13 is preferably 1.0 mm or less to increase the adhesive strength by applying sufficient heat to the adhesive bonding the decorative material 13 to the second wood fiber board 12. In this embodiment, the decorative material 13 is preferably composed of a single light-colored board. Examples of wood species for this light-colored board include maple, paulownia, camphor, chestnut, linden, oak, birch, ash, ash, horse chestnut, oak, elm, beech, sycamore, and cherry. The wood species for the light-colored board are not limited to the above-mentioned tree species. In this way, by forming decorative material 13 from a single light-colored board, it is possible to reduce the color difference between decorative material 13 and second wood fiber board 12, which is made of softwood MDF and has a light color. Therefore, it is possible to reduce the color difference between decorative material 13 and second wood fiber board 12 in groove portion 14 using coating film 3, or to eliminate this effort. Furthermore, even if decorative material 13 is thin, the design is only slightly impaired by the reflection of second wood fiber board 12, allowing for greater freedom in selecting the thickness of decorative material 13.

[0050] The adhesive used to bond the surface of the wood substrate 10 to the back surface of the first wood fiber board 11, the adhesive used to bond the surface of the first wood fiber board 11 to the back surface of the second wood fiber board 12, and the adhesive used to bond the surface of the second wood fiber board 12 to the decorative material are not particularly limited. When the first wood fiber board 11 is hardwood MDF, a modified vinyl acetate adhesive can be used as the adhesive to bond the wood substrate 10 to the first wood fiber board 11, and a urea-melamine resin adhesive can be used as the adhesive to bond the wood fiber boards 11, 12 together. When the decorative material 13 is wood, a urea-melamine resin adhesive can be used as the adhesive to bond the second wood fiber board 12 to the decorative material 13. On the other hand, when the decorative material 13 is a decorative sheet, a water-based adhesive or a hot-melt adhesive can be used as the adhesive to bond the second wood fiber board 12 to the decorative material 13. It is preferable that the adhesive for bonding the wood fiber boards 11 and 12 together be placed at least at a location on the second wood fiber board 12 that faces up and down to the location where the groove portion 14 is formed, in order to prevent the paint for forming the coating film from seeping into the groove portion 14.

[0051] The grooves 14 are formed along the length of the wood composite material 2. The grooves 14 are formed in the decorative material 13 and the second wood fiber board 12, and are, for example, V-shaped in a cross section perpendicular to the length of the wood composite material 2. The cross-sectional shape of the grooves 14 is not particularly limited. For example, the grooves 14 may be R-shaped grooves with curved cross-sectional shapes or VR-shaped grooves with cross-sectional shapes that combine straight and curved surfaces. The grooves 14 may be formed throughout the decorative material 13 and the second wood fiber board 12, and their depth is not limited. However, it is preferable that the depth of the grooves 14 be within the thickness of the second wood fiber board 12. If the grooves 14 reach the first wood fiber board 11, the first wood fiber board 11 would be exposed on the surface of the wood composite material 2, and the difference in color between the bottom of the groove and the opening of the groove would detract from the design. The angle formed by the pair of side surfaces of the groove 14 is not particularly limited, but can be, for example, about 30 to 120 degrees.

[0052] The figure illustrates an example in which groove 14 is formed at the middle position in the width direction of wood composite material 2. However, this does not have to be the case. Groove 14 may be a half groove (a portion that functions as a single groove when combined with adjacent products when installed as a product) provided on the four sides of the periphery of the surface of wood composite material 2, or a chamfered portion. If the width of wood composite material 2 is small, groove 14 may not be formed along the length of wood composite material 2 at the middle position in the width direction, but may be formed only on the periphery of wood composite material 2.

[0053] Furthermore, the grooves 14 may be formed by horizontal grooves extending along the width direction in addition to vertical grooves extending along the length direction. In the case of a composite wood material 2 having a herringbone design, the grooves 14 extend diagonally relative to the length direction and width direction. In this way, the orientation and placement of the grooves 14 are determined appropriately depending on the design conditions of the composite wood material 2, and are not limited to specific conditions.

[0054] The coating film 3 is formed on the surface of the decorative material 13 and the surface of the grooves 14 by applying a transparent paint, a translucent paint, or a colored paint to the surface of the wood composite material 2 and drying it. Examples of the paint include water-based paint, solvent-based paint, and solventless paint. The thickness of the coating film 3 is not particularly limited.

[0055] 2. Manufacturing method of flooring material 1 according to this embodiment Referring to FIGS. 1(A) to 4(B), the flooring material 1 according to this embodiment can be manufactured by the following steps. (A1) A preparation step of individually preparing a wood base material 10, a first wood fiber board 11, a second wood fiber board 12, and a decorative material 13; (A2) a bonding step of laminating and bonding the wood base material 10, the first wood fiber board 11, the second wood fiber board 12, and the decorative material 13 to form a composite material 40; (A3) a groove forming step of forming grooves 14 in the decorative material 13 and the second wood fiber board 12 of the composite material 40 to form the wood composite material 2; (A4) A coating process in which the surface of the decorative material 13 and the groove portion 14 of the wood composite material 2 is coated to form a coating film 3, thereby converting the wood composite material 2 into a flooring material 1. A more specific explanation will be given below.

[0056] <(A1) Preparation step of individually preparing the wood base material 10, the first wood fiber board 11, the second wood fiber board 12, and the decorative material 13> The wood base material 10, the first wood fiber board 11, the second wood fiber board 12, and the decorative material 13 are each prepared as a single piece of the above-mentioned material.

[0057] For the first wood fiber board 11, the first material wood fiber board 21 is divided along the board surface direction at multiple positions in the thickness direction of the first material wood fiber board 21 to form multiple (e.g., two) first divided boards 31, and one of the multiple first divided boards 31 serves as the first wood fiber board 11. The first divided board 31 that will become the first wood fiber board 11 is preferably polished to a predetermined thickness to become the first wood fiber board 11. The first material wood fiber board 21 may be divided into three or more pieces, but it is preferable that the first divided board 31 that will become the first wood fiber board 11 includes a relatively dense rock layer in the first material wood fiber board 21.

[0058] For the second wood fiber board 12, the second material wood fiber board 22 is divided along the board surface direction at multiple positions in the thickness direction of the second material wood fiber board 22 to form multiple (e.g., four) second divided plates 32, and one of the multiple second divided plates 32 serves as the second wood fiber board 12. The second divided plates 32 that will become the second wood fiber board 12 are preferably ground to a predetermined thickness. The number of second divided plates 32 formed from the second material wood fiber board 22 (number of divisions) may be two, three, or more than four. For the second divided plates 32 that will become the second wood fiber board 12, it is preferable from the standpoints of production and cost to set the thickness when divided from the second material wood fiber board 22 to a value close to the desired final thickness and then adjust to the final thickness by grinding. The second divided board 32 that will become the second wood fiber board 12 preferably contains the rock layer of the second material wood fiber board 22, which has a relatively high density.

[0059] <(A2) Adhesion step of laminating and adhering the wood base material 10, the first wood fiber board 11, the second wood fiber board 12, and the decorative material 13 to form the composite material 40> When forming the composite material 40, various patterns can be considered for the order in which the wood base material 10, first wood fiber board 11, second wood fiber board 12, and decorative material 13 are layered and bonded together. For example, the following patterns 1 to 3 can be exemplified. When bonding the components together, an appropriate bonding method can be selected, such as hot pressing or room temperature pasting.

[0060] An example of pattern 1 is a pattern in which a first wood fiber board 11 is bonded to a wood base material 10, then a second wood fiber board 12 is bonded to the first wood fiber board 11, and then a decorative material 13 is bonded to form a composite material 40, as shown in Figure 3.

[0061] An example of pattern 2 is a pattern in which, as shown in Figure 3, wood fiber boards 11 and 12 are bonded together, then a wood base material 10 is bonded to the composite fiber board formed by bonding the wood fiber boards 11 and 12 together, and then a decorative material 13 is bonded to the second wood fiber board 12 to form a composite material 40.

[0062] An example of pattern 3 is a pattern in which, as shown in Figure 3, wood fiber boards 11 and 12 are bonded together, then a decorative material 13 is bonded to the composite fiber board formed by bonding the wood fiber boards 11 and 12 together, and then a wood base material 10 is bonded to the first wood fiber board 11 to form a composite material 40.

[0063] Since the second wood fiber board 12 and the decorative material 13 are both extremely thin, it is not practical to bond these second wood fiber boards 12 and decorative material 13 together, but such a bonding process is not excluded.

[0064] In addition, examples of the adhesive used to bond the wood base material 10 and the first wood fiber board 11, the adhesive used to bond the wood fiber boards 11 and 12 together, and the adhesive used to bond the second wood fiber board 12 and the decorative material 13 include those described above.

[0065] A more specific example of a method for overlapping and bonding a wood base material 10, a first wood fiber board 11, a second wood fiber board 12, and a decorative material 13 is to apply a modified vinyl acetate adhesive to the wood base material 10, attach a first wood fiber board 11 made of hardwood MDF, and heat-pressure combine to form a composite base material, then apply a urea-melamine resin adhesive to the first wood fiber board 11 of this composite base material, attach a second wood fiber board 12 made of softwood MDF, and then temporarily pressurize the board, apply urea-melamine resin adhesive on top, and attach a decorative material 13 to perform heat-pressure combine (simultaneous bonding).

[0066] A more specific example of a method for overlapping and adhering a wood base material 10, a first wood fiber board 11, a second wood fiber board 12, and a decorative material 13 is the use of a decorative sheet as the decorative material 13. In this case, a modified vinyl acetate adhesive is applied to the wood base material 10, and a first wood fiber board 11 made of hardwood MDF is attached and heat-pressed to form a composite substrate. Next, a urea-melamine resin adhesive is applied to the first wood fiber board 11 of the composite substrate, and a second wood fiber board 12 made of softwood MDF is attached and heat-pressed. Next, a decorative sheet is attached to the composite substrate with a water-based adhesive or hot-melt adhesive, etc., up to the second wood fiber board 12.

[0067] <(A3) Groove forming step of forming grooves 14 in the composite material 40 to form the wood composite material 2> In this process, as shown in Figure 4(A), grooves are formed in the decorative material 13 of the composite material 40 and the second wood fiber board 12 using a cutter or the like to form grooves 14 in the composite material 40, and the wood composite material 2 is formed.

[0068] <(A4) A coating process in which the surfaces of the decorative material 13 and the grooves 14 in the wood composite material 2 are coated to form the coating film 3, thereby converting the wood composite material 2 into the flooring material 1> In this process, as shown in FIG. 4(B), the above-mentioned paint is applied to the decorative material 13 and the grooves 14 of the wood composite material 2 having the grooves 14 formed therein, and then dried to form a flooring material 1 having a coating film 3 formed on the surface of the wood composite material 2. The method of applying the paint in the painting process is not particularly limited. Examples of application methods include a flow coater (curtain coater) that applies the paint thickly, a roll coater, and spray application. Of these application methods, when using a flow coater to apply the paint thickly, the absorption of paint into the grooves 14 has a significant impact on the design of the flooring material 1. Note that in roll coater and spray application, the absorption of paint into the grooves 14 also affects the design of the flooring material 1.

[0069] As described above, in this embodiment, the grooves 14 are formed in the decorative material 13 and the second wood fiber board 12, and the second wood fiber board 12 is made of softwood MDF. The first wood fiber board 11 is bonded to the back surface of the second wood fiber board 12. This configuration allows the second wood fiber board 12 to be thin. This reduces dimensional changes in the second wood fiber board 12 in the wood composite material 2, such as dimensional changes due to moisture from the building or due to drying when underfloor heating is in use. Furthermore, when the decorative material 13 is made of a light-colored board, both the decorative material 13 and the second wood fiber board 12 are light-colored. This reduces the color difference between the decorative material 13 and the second wood fiber board 12 in the grooves 14, preventing the color of the base (the second wood fiber board 12) from showing through. Furthermore, the paint used to form the coating film 3 on the surface of the wood composite material 2 does not need to be a colored paint, and a transparent paint can be used. This allows for a natural finish with excellent design. Furthermore, because an adhesive layer is provided between the second wood fiber board 12 and the first wood fiber board 11, the paint is prevented from seeping below this adhesive layer. Therefore, the paint is absorbed into the second wood fiber board 12, which is formed to be moderately thin, in the grooves 14. As a result, the paint is applied appropriately to the surface of the grooves 14, preventing paint from pooling in the grooves 14. This results in a natural finish with even better design. Furthermore, when the decorative material 13 is made of a dark-colored board, a color difference occurs between the decorative material 13 and the light-colored second wood fiber board 12 in the grooves 14, so a colored paint is required as a material for the coating film 3. However, as described above, the second wood fiber board 12 can be made moderately thin, and because an adhesive layer is provided between the second wood fiber board 12 and the first wood fiber board 11, the paint is prevented from seeping below the adhesive layer into the first wood fiber board 11. Therefore, the colored paint is absorbed into the second wood fiber board 12 in the grooves 14 in an appropriate amount. As a result, the paint is applied to the surface of the grooves 14 in an appropriate amount, and the coating film 3 can be reliably formed in the grooves 14. Therefore, even if dirt occurs in the grooves 14, the dirt will adhere to the coating film 3, making it easy to wipe off the dirt by hand.Furthermore, if the coating film 3 is not formed in the grooves 14, moisture or wax may seep into the second wood fiber board 12, causing swelling or mold. However, this prevents such problems. Furthermore, because the coating film 3 is applied to the grooves 14 in an appropriate amount, the formation of paint pools in the grooves 14 is prevented. As a result, a natural color can be achieved across the decorative material 13 and the second wood fiber board 12 in the grooves 14, resulting in a natural finish with excellent design. Furthermore, because the coating film 3 penetrates the second wood fiber board 12 to a certain extent, adhesion between the coating film 3 and the wood composite material 2 is improved, preventing peeling of the coating film 3 from the wood composite material 2 and reducing degradation of the design. Furthermore, because the second wood fiber board 12, made of MDF, which is stronger than veneer, is placed directly below the decorative material 13, scratch resistance, such as resistance to dents when a heavy object is dropped, is ensured. As a result, it is possible to realize a wood composite material 2 that can suppress warping caused by dimensional changes due to humidity changes, etc., has excellent design, and is sufficiently scratch-resistant.

[0070] Furthermore, in this embodiment, when the first wood fiber board 11 is made of hardwood MDF, the first wood fiber board 11 can be made of a material that undergoes less dimensional change due to humidity changes than softwood, which makes it possible to more reliably suppress warping of the wood composite material 2.

[0071] Furthermore, in this embodiment, the second wood fiber board 12 is thinner than the first wood fiber board 11, so that the paint that is the material of the coating film 3 is absorbed appropriately into the second wood fiber board 12. Furthermore, dimensional changes in the second wood fiber board 12 caused by humidity changes are small, so warping of the flooring material 1 can be reduced.

[0072] Furthermore, according to this embodiment, even when the decorative material 13 is a light-colored board, it is possible to reduce the degree to which the second wood fiber board 12 made of softwood MDF is visible through the decorative material 13. Therefore, even when the decorative material 13 is a light-colored board, it is possible to achieve a natural color of the flooring material 1, and the design of the flooring material 1 can be improved.

[0073] Furthermore, according to this embodiment, when the wood substrate 10 includes a coniferous tree layer, tree species that are relatively widespread in Japan, such as cedar and cypress, can be effectively used for the flooring material 1. In particular, when the wood substrate 10 includes both a coniferous tree layer and a broad-leaved tree layer, the use of broad-leaved trees, which experience minimal dimensional change due to humidity changes, can more reliably prevent warping of the flooring material 1.

[0074] In the above embodiment, the wood composite material 2 is used as a flooring material. However, this is not necessarily the case. The wood composite material 2 may be used for other purposes, such as a wall material. [Example]

[0075] In order to confirm the effects of the present invention, flooring materials of Example, Comparative Example 1, Comparative Example 2, and Comparative Example 3 were produced.

[0076] <Production Method of Example> A composite substrate was produced by applying a modified vinyl acetate adhesive to the surface of a wood substrate made of softwood plywood, then laminating a first wood fiberboard made of hardwood MDF and thermocompressing the two together. Next, a urea-melamine resin adhesive was applied to the surface of the first wood fiberboard in the composite substrate, and a second wood fiberboard made of softwood MDF was then laminated. This was then temporarily pressed together, and another urea-melamine resin adhesive was applied on top of that. A decorative board was then laminated and thermocompressed (simultaneous lamination) to produce a wood composite. Grooves were then formed in the decorative material and the second wood fiberboard of the wood composite, and paint was applied to the surface of the wood composite using a flow coater to complete the flooring material.

[0077] <Production method of Comparative Example 1> A composite substrate was produced by applying a modified vinyl acetate adhesive to the surface of a wood substrate made of softwood plywood, and then laminating a wood fiberboard made of hardwood MDF and thermocompressing the material. Next, a urea-melamine resin adhesive was applied to the surface of the wood fiberboard in the composite substrate, and then a decorative board was laminated and thermocompressed to produce a wood composite. Next, grooves were formed in the decorative material and wood fiberboard of the wood composite, and then paint was applied to the surface of the wood composite using a flow coater to complete the flooring material.

[0078] <Production method of Comparative Example 2> A composite substrate was produced by applying a modified vinyl acetate adhesive to the surface of a wood substrate made of softwood plywood, and then laminating a wood fiberboard made of softwood HB and thermocompressing the material. Next, a urea-melamine resin adhesive was applied to the surface of the wood fiberboard in the composite substrate, and then laminating a decorative board and thermocompressing the material to produce a wood composite. Next, grooves were formed in the decorative material and wood fiberboard of the wood composite, and then paint was applied to the surface of the wood composite using a flow coater to complete the flooring material.

[0079] <Production method of Comparative Example 3> A flooring material was produced that was constructed in the same manner as in Comparative Example 1, except that softwood MDF was used as the wood fiberboard.

[0080] <Materials and thicknesses of Examples and Comparative Examples 1 to 3> The configuration of the embodiment is as follows. Wood substrate: 10.0 mm softwood plywood (with backer paper) First wood fiberboard: 1.2mm hardwood MDF Second wood fiberboard: 0.47mm softwood MDF Decorative material: 0.3mm veneer (maple)

[0081] The configuration of Comparative Example 1 is as follows. Wood base material: 9.0mm softwood plywood Wood fiberboard: 2.7mm hardwood MDF Decorative material: 0.3mm veneer (maple)

[0082] The configuration of Comparative Example 2 is as follows. Wood substrate: 10.0 mm softwood plywood (with backer paper) Wood fiberboard: 1.8mm softwood HB Decorative material: 0.3mm veneer (maple)

[0083] The configuration of Comparative Example 3 is as follows. Wood base material: 9.0mm softwood plywood Wood fiberboard: 2.7mm softwood MDF Decorative material: 0.3mm veneer (maple)

[0084] As is clear from the above explanation, two wood fiber boards, a first and a second wood fiber board, are provided in the Example, whereas only one wood fiber board is provided in Comparative Examples 1 to 3. The dimensions of the Example and Comparative Examples 1 to 3 are all 303 mm wide x 1818 mm long.

[0085] <Test Method> Test 1 (drying test): The sample was left in a dry environment at a temperature of 40°C and a humidity of 30% for two weeks, and the dimensional change before and after the test was measured. Test 2 (moisture absorption test): The sample was left in a moisture-absorbing environment at a temperature of 30°C and a humidity of 90% for two weeks, and the dimensional change before and after the test was measured. In addition, in Tests 1 and 2, the design of the grooves was visually evaluated. The results are shown in Table 1 [Table 1]

[0086] <Evaluation of dimensional changes> The dimensional change rate was evaluated. The dimensional change rate (% / %) is the amount of dimensional change per 1% of moisture content, calculated by dividing the amount of dimensional change (%) due to the drying or moisture absorption of the wood by the size before the test, and dividing this amount by the amount of change (%) in the moisture content of the wood due to drying or moisture absorption. The moisture content was measured using the total dry method, which measures the total dry weight of the product, and the total dry moisture content was used for calculations.

[0087] For example, if the original dimension was 1818 mm and it was 1816 mm after the drying test, the change was 2 mm, and the dimensional change was 2 mm / 1818 mm = 0.11 (%). For example, if the moisture content changed by 4% after the drying test, the dimensional change rate would be 0.11 (%) / 4 (%) = 0.0275 (% / %). The larger the dimensional change rate, the larger the amount of dimensional change when the moisture content changes by 1%, and it can be said that warping and gaps are more likely to occur (larger behavior).

[0088] In the drying test, the dimensional change rate of the Examples was the smallest in both the length direction and the width direction, demonstrating that the degree of dimensional change due to drying is extremely small. In addition, in the moisture absorption test, the dimensional change rate of the Examples was greater than that of Comparative Examples 1 and 3 in both the length direction and the width direction, but was significantly smaller than the dimensional change rate of the Examples in the drying test, demonstrating that the degree of dimensional change due to moisture absorption is extremely small.

[0089] As is clear from Comparative Examples 2 and 3, when the wood fiberboard is entirely made of softwood, even if it is thin (even if the ratio to plywood is small), dimensional change is greater than with hardwood, resulting in significant warping when humidity changes, especially during drying. In the Examples, dimensional change was suppressed by reducing the thickness ratio of softwood MDF as the second wood fiberboard, demonstrating minimal behavior in response to humidity changes. Since dimensional change can be minimized, especially under dry conditions, warping and gaps can be minimized when using underfloor heating.

[0090] <Design evaluation> For Examples and Comparative Examples 1 to 3, both electron microscope observation and visual inspection with the naked eye were performed. For electron microscope observation, a cross section perpendicular to the longitudinal direction was magnified 100 times with an electron microscope, and the magnified image was photographed. The magnified image was then used to determine whether a coating film was formed on the entire surface of the decorative material and the grooves, and whether there were any problems with the coating film in the grooves based on the presence of paint pools at the bottom of the grooves. The same judgments were made in the visual inspection with the naked eye as those made using the photographed images.

[0091] The presence or absence of paint accumulation was judged mainly by visual inspection with the naked eye, and whether or not a coating film had been formed over the entire surface of the decorative material and groove portion was judged mainly by images taken using an electron microscope.

[0092] The evaluation was as follows: ○: No problem with the design of the groove. ×: There are some grooves where the coating film does not remain. ××: There are areas where paint has accumulated in the grooves. As long as a coating film is formed on the surface of the flooring material, there are no problems with dirt or the absorption of water or wax, so the evaluation was based on the presence or absence of a coating film.

[0093] In Comparative Examples 1 and 3, the grooves absorbed too much paint, resulting in some areas where the paint film did not remain, resulting in a rating of ×. In Comparative Example 2, the high surface density of the HB made it difficult for the paint to penetrate, resulting in some areas where paint pooled in the grooves, and in the electron microscope photograph, the cross section of the paint film on the grooves was U-shaped rather than V-shaped, resulting in a rating of ××. In Comparative Example 2, the grooves appeared to be filled with paint when visually inspected. Note that, as in Comparative Example 2, the wood fiberboard was 1.8 mm thick with HB and had a surface density of 1.1 g / cm. 3 In contrast, in the example, the wood fiber board was polished to a thickness of 0.3 to 0.4 mm so as to leave the relatively dense rock layer, and the measured surface density was 0.85 g / cm on average. 3 (0.83~0.88g / cm 3 ) The surface density of MDF, which is also a wood fiberboard, was 1.1 g / cm 3 If the color is too dark, it can be said that there is a risk of paint puddling, just like with HB. Furthermore, the HB of Comparative Example 2 uses softwood material, but is dark in color due to manufacturing. Therefore, when using a light-colored board as a decorative material, coloring of the groove is necessary. On the other hand, in the Example, a coating film of appropriate thickness is formed over the entire groove, there is no paint puddling, and the coating film in the groove is formed in a V-shaped cross section. There are no problems with the design finish of the groove, and it is rated ○, demonstrating excellent design. [Industrial Applicability]

[0094] According to the present invention, a wood composite material, a flooring material, and a method for manufacturing the same can be provided. [Explanation of symbols]

[0095] 1. Flooring 2 Wood composite material 3 Coating 10 Wood base material 11 First wood fiberboard 12 Second wood fiberboard 13 Cosmetic materials 14 Groove 21 The first material: wood fiberboard 22 Second Material: Wood Fiberboard 31 First dividing plate 32 Second dividing plate

Claims

1. A wood substrate and a first wood fiber board adhered to the surface of the wood substrate; a second wood fiber board adhered to the surface of the first wood fiber board; a decorative material adhered to the surface of the second wood fiber board; Grooves formed in the decorative material and the second wood fiber board; Equipped with A wood composite material, wherein the second wood fiber board is softwood MDF.

2. The wood composite of claim 1 , wherein the first wood fiber board is hardwood MDF.

3. The density of the softwood MDF is 0.70 g / cm ３ The density of the hardwood MDF is 0.70 g / cm or more. ３ The wood composite material according to claim 2, which satisfies at least one of the above conditions.

4. The wood composite material according to any one of claims 1 to 3, wherein the second wood fiber board is thinner than the first wood fiber board.

5. The wood composite material according to any one of claims 1 to 4, wherein the decorative material is a light-colored board.

6. The wood composite material according to any one of claims 1 to 5, wherein the wood substrate includes a coniferous layer.

7. The composite wood material according to any one of claims 1 to 6, a coating film formed on the surface of the decorative material and the surface of the groove portion; The flooring is provided with:

8. A wood substrate and a first wood fiber board adhered to the surface of the wood substrate; a second wood fiber board adhered to the surface of the first wood fiber board; a decorative material adhered to the surface of the second wood fiber board; Grooves formed in the decorative material and the second wood fiber board; Equipped with A method for producing a wood composite material, wherein the second wood fiber board is softwood MDF, A method for manufacturing a wood composite material, comprising the steps of: preparing the wood base material, the first wood fiber board, the second wood fiber board, and the decorative material separately; and then stacking the wood base material, the first wood fiber board, the second wood fiber board, and the decorative material together.

9. Dividing the first material wood fiber board along the board surface direction at a plurality of positions in the thickness direction of the first material wood fiber board to form a plurality of first divided boards; The method for manufacturing a wood composite material according to claim 8 , wherein any one of the plurality of first divided plates is the first wood fiber plate.

10. Dividing the second material wood fiber board along the board surface direction at a plurality of positions in the thickness direction of the second material wood fiber board to form a plurality of second divided boards; The method for manufacturing a wood composite material according to claim 8 or claim 9, wherein any one of the plurality of second divided plates is the second wood fiber plate.

11. The method for manufacturing a wood composite material according to claim 10, wherein the divided boards that become the wood fiber boards include a relatively dense rock layer in the raw wood fiber board.

12. The method for manufacturing a wood composite material according to claim 11, wherein the divided boards that will become the wood fiber boards are arranged with the rock layer facing the decorative material.

13. A step of forming grooves in the decorative material and the second wood fiber board of the wood composite material according to any one of claims 8 to 12; a coating step of coating the wood composite material in which the grooves are formed; A method for manufacturing a flooring material, comprising:

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