Wood material sheet and manufacturing method of the same and molded item and manufacturing method of molded item

Abstract

To provide a wood material sheet which can inhibit poor appearance from being caused during processing and due to temporal change.SOLUTION: A wood material sheet according to the disclosure includes: a natural wood material; a protection layer disposed on one surface of the wood material; a support layer disposed on the other surface of the wood material; a first adhesion layer provided on a wood material side surface in the protection layer; a second adhesion layer provided between the first adhesion layer and the wood material; and a thermoplastic shape follow-up layer provided between the wood material and the support layer. The first adhesion layer and the second adhesion layer are not integrated. A border is formed between the first adhesion layer and the second adhesion layer.SELECTED DRAWING: Figure 1A

Description

[Technical field]

[0001] The present disclosure relates to a wood sheet and molded product using natural wood, and a method for manufacturing a wood sheet and a method for manufacturing a molded product. [Background technology]

[0002] In recent years, in the field of decorative methods for the surfaces of parts and panels used in the fields of home appliance exteriors and automotive interiors, a wide range of design expressions and high-quality design are required due to diversifying customer orientation and the recent trend toward authenticity and high quality. Among them, wood sheets made from natural wood are actively used as decorative materials because they provide users with the texture derived from the material, such as the feel and appearance, and a luxurious expression with excellent design. In this specification, decorative materials refer to materials in sheet form with a thickness of 5 mm or less.

[0003] Patent Document 1 discloses a wood decorative board in which a transfer layer is formed on the upper part of a veneer. Figures 9 and 10 show the wood decorative board described in Patent Document 1.

[0004] As shown in Fig. 9, the wood decorative board described in Patent Document 1 is composed of a transfer layer 101, a veneer 102, a nonwoven fabric 103, and a first adhesive layer 104. The transfer layer 101 is transferred to one side of the veneer 102 by heat pressing, forming irregularities 106 similar to the irregular surface shape of the veneer 102. Furthermore, the veneer 102 is impregnated with a resin such as polyethylene glycol as necessary.

[0005] 10, the transfer layer 101 is composed of a hard coat layer 108 and a veneer adhesive layer 107 on a release layer 109 of a base film 110. The transfer layer 101 acts as a protective layer for the surface of the veneer 102. Because the transfer layer 101 is a thin film, it improves the durability of the product while maintaining the original feel and appearance of the veneer 102. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2019-64168 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, the wood decorative board described in Patent Document 1 still has room for improvement in terms of preventing poor appearance.

[0008] In order to solve the above-mentioned problems, the present disclosure aims to provide a wood sheet in which the occurrence of poor appearance due to processing and changes over time is suppressed. [Means for solving the problem]

[0009] A wood sheet of one embodiment of the present disclosure comprises a wood material made of natural wood, a protective layer arranged on one side of the wood material, a support layer arranged on the other side of the wood material, a first adhesive layer provided on the surface of the protective layer facing the wood material, a second adhesive layer provided between the first adhesive layer and the wood material, and a thermoplastic shape-conforming layer provided between the wood material and the support layer, wherein the first adhesive layer and the second adhesive layer are not integral with each other, and there is a boundary between the first adhesive layer and the second adhesive layer.

[0010] A manufacturing method for a wood sheet according to one embodiment of the present disclosure includes the steps of forming a first adhesive layer on one side of a protective layer, forming a second adhesive layer on one side of the wood material, and stacking, in order, the protective layer, the wood material with the second adhesive layer positioned opposite the first adhesive layer formed on the protective layer, a thermoplastic shape-conforming layer positioned opposite the other side of the wood material, and a support layer, and thermocompressing them to form a laminate.

[0011] A molded product according to one embodiment of the present disclosure has a wood sheet and a resin housing arranged on the support layer side of the wood sheet.

[0012] A manufacturing method for a molded product of one embodiment of the present disclosure includes a step of forming a first adhesive layer on one side of a protective layer, a step of forming a second adhesive layer on one side of a wooden material, a step of sequentially stacking and thermocompressing the protective layer, the wooden material with the second adhesive layer positioned opposite the first adhesive layer formed on the protective layer, a thermoplastic shape-conforming layer positioned opposite the other side of the wooden material, and a support layer to form a laminate, and a step of forming a resin casing on the support layer side of the laminate. Effect of the Invention

[0013] According to the present disclosure, it is possible to provide a wood sheet in which the occurrence of poor appearance due to processing and changes over time is suppressed. [Brief description of the drawings]

[0014] [Figure 1A] FIG. 1 is a schematic cross-sectional view showing a cross-sectional structure of a wood sheet according to a first embodiment of the present disclosure. [Figure 1B] FIG. 1B is a partially enlarged SEM image of the cross section of the wood sheet of FIG. 1A. [Diagram 2] FIG. 2 is a cross-sectional view of a transfer film used in manufacturing a wood sheet according to the first embodiment of the present disclosure. [Diagram 3] 3 is a cross-sectional view of a second adhesive layer and wood material that constitute a part of the wood sheet according to the first embodiment of the present disclosure. FIG. [Figure 4] FIG. 2 is a cross-sectional view of the wood sheet according to the first embodiment of the present disclosure before a thermocompression bonding process. [Diagram 5] FIG. 2 is a cross-sectional view of the wood sheet according to the first embodiment of the present disclosure during a thermocompression bonding process. [Figure 6] FIG. 2 is a cross-sectional view of the wood sheet according to the first embodiment of the present disclosure after a thermocompression bonding process. [Figure 7] FIG. 2 is a cross-sectional view of a modified example of the wood sheet according to the first embodiment of the present disclosure. [Figure 8] FIG. 11 is a schematic cross-sectional view showing a cross-sectional structure of a molded product according to a second embodiment of the present disclosure. [Figure 9] FIG. 2 is a cross-sectional view of the wooden decorative molding disclosed in Patent Document 1. [Figure 10]FIG. 1 is a cross-sectional view of the transfer film of Patent Document 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] (Background to this disclosure) When wood sheets are used for the exterior of home appliances or the interior of vehicles, a protective layer conforming to the shape of the veneer surface formed from the wood is formed to improve the durability of the product while maintaining the original texture and appearance. The protective layer is formed by hot pressing the wood.

[0016] During the hot press processing, the moisture in the wood material turns into water vapor and flows out from the wood material toward the protective layer. However, the protective layer prevents the water vapor from flowing out further, which causes convex bubbles to form on the surface of the protective layer, resulting in poor appearance of the wood sheet.

[0017] Furthermore, when the wood is impregnated with resin, the heat during hot pressing causes the resin to soften and seep out onto the surface of the protective layer, resulting in stickiness or greasiness, which in turn leads to poor appearance of the wood sheet. Furthermore, deterioration over time can also lead to poor appearance.

[0018] Therefore, the inventors of the present invention conducted extensive research into the occurrence of poor appearance caused by processing and changes over time, and came up with a structure in which a second adhesive layer, different from the first adhesive layer, which acts as a barrier layer on the surface of the wood material, is formed in advance on the surface of the wood material. This structure prevents substances from migrating from the wood material to the protective layer. It was found that this can prevent poor appearance of the wood sheet.

[0019] Based on these novel findings, the present inventors have made the following disclosure.

[0020] The wood sheet of the first embodiment of the present disclosure comprises a wood material made of natural wood, a protective layer arranged on one side of the wood material, a support layer arranged on the other side of the wood material, a first adhesive layer provided on the surface of the protective layer facing the wood material, a second adhesive layer provided between the first adhesive layer and the wood material, and a thermoplastic shape-conforming layer provided between the wood material and the support layer, wherein the first adhesive layer and the second adhesive layer are not integral with each other, and there is a boundary between the first adhesive layer and the second adhesive layer.

[0021] With this configuration, since the second adhesive layer is provided on the surface of the wood material, the migration of substances from the wood material to the protective layer is suppressed, thereby making it possible to suppress the occurrence of defects in the appearance of the wood sheet.

[0022] In the second embodiment of the wood sheet of the present disclosure, the wood has an uneven surface, and the second adhesive layer penetrates into the recesses of the uneven surface of the wood, and there may be no air layer between the second adhesive layer and the uneven surface of the wood.

[0023] With this configuration, there is no air layer between the wood material and the second adhesive layer, so that substances flowing out of the wood material cannot move over the surface of the wood material, and the movement of substances can be limited to within the wood material.

[0024] In the wood sheet according to the third embodiment of the present disclosure, the first adhesive layer and the second adhesive layer may each have a cross-linked structure.

[0025] With this configuration, the first adhesive layer and the second adhesive layer have a dense structure.

[0026] In the wood sheet according to the fourth embodiment of the present disclosure, the first adhesive layer may contain a blocked isocyanate curing agent and may have urethane bonds.

[0027] With this configuration, a cross-linked structure is formed in the first adhesive layer.

[0028] In the wood sheet according to the fifth embodiment of the present disclosure, the first adhesive layer may have an average thickness of 3 μm or more and 100 μm or less, and the second adhesive layer may have an average thickness of 10 μm or more and 100 μm or less.

[0029] With this configuration, the adhesiveness of the first adhesive layer and the function of the second adhesive layer as a barrier layer can be improved, and furthermore, the manufacturing costs of the wood sheet can be reduced.

[0030] The wood sheet of a sixth embodiment of the present disclosure further comprises a release layer arranged on the side of the protective layer opposite the first adhesive layer, and a base film arranged on the side of the release layer opposite the protective layer, wherein the protective layer has a total thickness of 3 μm or more and 100 μm or less, has a hard coat function and a UV-cut function, and the release layer and the base film may be removable from the protective layer at the interface between the release layer and the protective layer.

[0031] With this configuration, the protective layer is protected by the base film, so the surface irregularities of the protective layer are not crushed. Therefore, the protective layer can be formed on the surface of the wood material while maintaining the original texture and appearance of the wood. Furthermore, the protective layer improves the protective function and shape conformability of the surface of the wood material. In addition, the protective layer has a hard coat function and a UV cut function, so that the protective layer protects the wood material from damage, deformation, deterioration due to UV rays, etc.

[0032] The wood sheet according to the seventh embodiment of the present disclosure may further include a third adhesive layer provided between the wood and the thermoplastic shape-conforming layer.

[0033] With this configuration, adhesive layers that function as barrier layers are formed on both sides of the wood material, thereby further suppressing the migration of substances from the wood material to the protective layer, thereby further suppressing the occurrence of poor appearance of the wood material sheet.

[0034] The molded product of the eighth embodiment of the present disclosure has a wood sheet and a resin housing arranged on the support layer side of the wood sheet.

[0035] With this configuration, it is possible to suppress the occurrence of defects in the appearance of the molded product and improve its strength.

[0036] A manufacturing method for a wood sheet according to a ninth aspect of the present disclosure includes the steps of forming a first adhesive layer on one side of a protective layer, forming a second adhesive layer on one side of the wood material, and sequentially stacking and thermocompressing the protective layer, the wood material with the second adhesive layer positioned opposite the first adhesive layer formed on the protective layer, a thermoplastic shape-conforming layer positioned opposite the other side of the wood material, and a support layer to form a laminate.

[0037] In this manner, the first adhesive layer and the second adhesive layer are formed in separate steps.

[0038] In the method for producing a wood sheet according to the tenth aspect of the present disclosure, the second adhesive layer may be formed by applying the second adhesive layer in a liquid state to the surface of the wood material.

[0039] In this manner, no air gap is formed between the second adhesive layer and the wood material.

[0040] In the method for producing a wood sheet according to the eleventh aspect of the present disclosure, the second adhesive layer may be cured prior to the step of forming the laminate.

[0041] In this manner, the second adhesive layer is cured before the wood sheet is thermocompression bonded, and can function as a barrier layer during the thermocompression bonding process.

[0042] A manufacturing method for a molded product of the twelfth embodiment of the present disclosure includes a step of forming a first adhesive layer on one side of a protective layer, a step of forming a second adhesive layer on one side of a wooden material, a step of sequentially stacking and thermocompressing the protective layer, the wooden material arranged with the second adhesive layer facing the first adhesive layer formed on the protective layer, a thermoplastic shape-conforming layer arranged opposite the other side of the wooden material, and a support layer to form a laminate, and a step of forming a resin housing on the support layer side of the laminate.

[0043] By such a method, a molded product having a resin housing can be formed.

[0044] (Embodiment 1) [Overall configuration] Fig. 1A is a cross-sectional view of a laminate according to the first embodiment of the present invention, which is made up of a wood sheet 31, a base film 51, and a release layer 52. Fig. 1B is an SEM image of a partially enlarged portion of the wood sheet 31 in Fig. 1A. Fig. 2 is a cross-sectional view of a transfer film 50.

[0045] As shown in FIG. 1A, the wood sheet 31 is composed of a laminate in which, viewed from the surface side, a protective layer 1, a first adhesive layer 2, a second adhesive layer 3, a wood material 4, a thermoplastic shape-conforming layer 5, and a support layer 6 are laminated in that order.

[0046] The components constituting the wood sheet 31, the base film 51, and the release layer 52 will be described below.

[0047] <Transfer film> 2, the transfer film 50 is a film consisting of a first adhesive layer 2, a protective layer 1, which are parts of the wood sheet 31, as well as a base film 51 and a peeling layer 52. The transfer film 50 serves to transfer the protective layer 1 to the wood material 4 in the manufacturing process of the wood sheet 31. After the protective layer 1 is transferred to the wood material 4, the base film 51 and the peeling layer 52 may be removed from the wood sheet 31 at the interface between the peeling layer 52 and the protective layer 1, if necessary.

[0048] <Base film> The base film 51 is disposed on the surface of the peeling layer 52 opposite to the protective layer 1, and plays a role in protecting the surface irregularities of the protective layer 1, which will be described later, in the manufacturing process of the wood sheet 31. The base film 51 is formed of a polymeric material such as polyethylene terephthalate resin, acrylic resin, polycarbonate resin, etc. The average thickness of the base film 51 may be, for example, 20 μm or more and 50 μm or less. Since the thickness of the base film 51 is 20 μm or more, it is possible to suppress the occurrence of wrinkles, tears, warping, etc. in the base film 51 due to heat drying, etc., in the process of forming each layer of the transfer film 50. In addition, since the thickness of the base film 51 is 50 μm or less, it is possible to improve the conformability of the base film 51 to the wood material 4. In addition, if the thickness of the base film 51 is 50 μm or less, when the transfer film 50 is formed of a roll film, the total weight of the transfer film 50 is reduced, improving the handling property of the transfer film 50 when it is carried around, and reducing the manufacturing cost.

[0049] <Release layer> The release layer 52 is disposed on the surface of the protective layer 1 opposite to the first adhesive layer 2, and serves to peel the base film 51 from the wood sheet 31. For example, the release layer 52 is formed of a thermosetting melamine resin, a two-component curing urethane resin, a thermosetting silicone resin, or the like. The thickness of the release layer 52 is not particularly limited, and can be selected arbitrarily as long as it has a peeling effect.

[0050] <Protective layer> The protective layer 1 is disposed on one surface of the wood material 4 in a state of conforming to the shape thereof via a first adhesive layer 2 and a second adhesive layer 3 described later. The protective layer 1 serves to protect the wood material 4 from damage, deformation, deterioration due to ultraviolet rays, and the like, and is formed of a material having a hard coat function and a UV cut function. An example of a material having a hard coat function is an after-cure type ultraviolet curing acrylic resin. When an after-cure type material is used, a laminate consisting of a wood material sheet 31, a base film 51, and a peeling layer 52 is formed, and after removing the base film 51 and the peeling layer 52, the protective layer 1 is cured by ultraviolet light and EB irradiation. By such a formation method, the protective layer 1 is not completely cured when the laminate is formed, and the protective layer 1 has improved conformability and is less likely to crack.

[0051] On the other hand, pre-cure type ultraviolet curing acrylic resin, heat drying type one-component acrylic resin, heat drying type two-component curing urethane acrylic resin, EB (electron beam) curing acrylic resin may be used as the material of the protective layer 1. Furthermore, other materials having a hard coat function and a UV cut function may be used.

[0052] The average thickness of the protective layer 1 may be, for example, 3 μm or more and 100 μm or less. In this specification, the average thickness refers to a value obtained by measuring the thickness of the layer at multiple points and calculating the average. It is more preferable that the average thickness of the protective layer 1 is 3 μm or more and 20 μm or less. Since the average thickness of the protective layer 1 is 20 μm or less, the distance to the wooden material 4 is close, and the original texture of the wooden material 4 can be expressed without feeling the sense of depth or gloss caused by the protective layer 1.

[0053] The protective layer 1 may be provided together with other functional layers, such as a layer containing an additive such as a filler, a colored layer, or a pattern layer, which are formed using a general printing technique.

[0054] <First adhesive layer> The first adhesive layer 2 is disposed between the protective layer 1 and the second adhesive layer 3, and serves to bond the protective layer 1 and the second adhesive layer 3. The first adhesive layer 2 is made of a resin. For example, the adhesive base of the first adhesive layer 2 is made of a vinyl chloride-vinyl acetate copolymer resin, an olefin-based resin, a polyolefin-based resin, a urethane-based resin, an acrylic-based resin, or the like, and forms a crosslinked structure within the layer. In addition, a blocked isocyanate-based curing agent is added as a curing agent of the first adhesive layer 2, and forms a crosslinked structure of the adhesive base and urethane bonds.

[0055] The first adhesive layer 2 is formed on the surface of the protective layer 1 by, for example, screen printing or a coater.

[0056] The average thickness of the first adhesive layer 2 may be, for example, 3 μm or more and 100 μm or less. In order to improve the conformability to the surface of the wood material 4, it is more desirable that the average thickness of the first adhesive layer 2 is 10 μm or more and 50 μm or less.

[0057] <Second adhesive layer> The second adhesive layer 3 is disposed between the first adhesive layer 2 and the wood material 4 along the surface of the wood material 4 in advance, and serves as a barrier layer that prevents substances in the wood material 4 from migrating into the protective layer 1. In the manufacturing method described below, the second adhesive layer 3 is cured before bonding to the first adhesive layer 2, so that a boundary 9 is formed between the first adhesive layer 2 and the second adhesive layer 3, as shown in Figures 1A and 1B, and they are not integrated. Furthermore, the second adhesive layer 3 penetrates into the recesses of the surface unevenness of the wood material 4. Therefore, as shown in Figure 1B, no air layer is formed between the second adhesive layer 3 and the wood material 4, especially in the recesses of the surface unevenness of the wood material 4, and the function of the second adhesive layer 3 as a barrier layer is improved.

[0058] The second adhesive layer 3 is made of a resin. For example, the adhesive base of the second adhesive layer 3 is made of a vinyl chloride-vinyl acetate copolymer resin, an olefin-based resin, a polyolefin-based resin, a urethane-based resin, an acrylic-based resin, or the like, and has a crosslinked structure within the layer. Processes for forming the crosslinked structure include, for example, ultraviolet light, EB irradiation, heat curing, catalytic reaction, and the like.

[0059] The average thickness of the second adhesive layer 3 may be, for example, 10 μm or more and 100 μm or less. Moreover, it is more preferable that the average thickness of the second adhesive layer 3 is 20 μm or more and 80 μm or less.

[0060] <Wood materials> The wood material 4 is formed from wood derived from natural wood that contains moisture inside, and has an uneven surface shape due to vessels, depressions, etc., as shown in Fig. 1B. The wood material 4 is a thinly sliced ​​sheet-shaped board material, and its average board thickness may be, for example, 0.1 mm or more and 2 mm or less. Since the average board thickness of the wood material 4 is 0.1 mm or more, breakage is prevented and workability is improved, while the average board thickness is 2 mm or less, so the wood material 4 can be sufficiently shaped into the product shape.

[0061] In order to improve the mechanical strength and toughness of the wood material 4, an organic resin is impregnated into the wood material 4. An organic resin having a chain structure may be impregnated into the wood material 4. For example, impregnation with an organic resin having a chain structure such as polyethylene glycol or a phenolic resin improves the flexibility of the wood material 4 and makes it easier to deform.

[0062] To improve the appearance or functionality, other materials such as pigments, phosphorescent paints, dyes, or flame retardants may be added to one or both sides of the wood material 4. Furthermore, one or both sides of the wood material 4 may be subjected to treatments such as bleaching or applying a pattern.

[0063] <Thermoplastic shape-conforming layer> The thermoplastic shape-conforming layer 5 is disposed between the wood material 4 and the support layer 6, and serves to bond the wood material 4 and the support layer 6 together. The thermoplastic shape-conforming layer 5 is made of a transparent thermoplastic material. For example, the thermoplastic shape-conforming layer 5 is made of an olefin-based or polyolefin-based component. The average thickness of the thermoplastic shape-conforming layer 5 may be, for example, 50 μm or more and 200 μm or less. Since the average thickness of the thermoplastic shape-conforming layer 5 is 50 μm or more, the adhesion between the wood material 4 and the support layer 6 is improved, and since the average thickness of the thermoplastic shape-conforming layer 5 is 200 μm or less, the manufacturing cost can be reduced.

[0064] <Support layer> The support layer 6 serves to improve the strength of the wood sheet 31. When pressure is applied to the wood sheet 31, the support layer 6 buffers the deformation, thereby preventing damage to the wood sheet 31. The support layer 6 is formed, for example, of a polymer film such as polyethylene terephthalate or acrylic, or a nonwoven fabric.

[0065] [effect] The wood sheet 31 according to the first embodiment has the following advantages.

[0066] The wood sheet 31 comprises a wood material 4 made of natural wood, a protective layer 1 arranged on one side of the wood material 4, and a support layer 6 arranged on the other side of the wood material 4. A first adhesive layer 2 is provided on the surface of the protective layer 1 facing the wood material 4, and a second adhesive layer 3 is provided between the first adhesive layer 2 and the wood material 4. A thermoplastic shape-conforming layer 5 is provided between the wood material 4 and the support layer 6. The first adhesive layer 2 and the second adhesive layer 3 are not integrated, and there is a boundary 9 between the first adhesive layer 2 and the second adhesive layer 3.

[0067] With this configuration, the second adhesive layer 3 is formed on the surface of the wood material 4, which inhibits the movement of water vapor and impregnated resin from the wood material 4 toward the protective layer 1 during thermocompression bonding and changes over time. The second adhesive layer 3 provided on the surface of the wood material 4 inhibits the generation of convex bubbles caused by water vapor, seepage of the impregnated resin, stickiness, or shine on the surface of the protective layer 1, and therefore inhibits the occurrence of poor appearance of the wood material sheet 31.

[0068] The wood material 4 has an uneven surface, the second adhesive layer 3 penetrates into the recesses S3 of the uneven surface of the wood material 4, and there is no air gap between the second adhesive layer 3 and the uneven surface of the wood material 4.

[0069] With this configuration, there is no air space between the wood material 4 and the second adhesive layer 3 or on the surface of the wood material 4 through which substances that may flow out of the wood material 4 can move. Therefore, the movement of substances that may flow out of the wood material 4 can be limited to the movement within the wood material 4 in the direction toward its end face.

[0070] The first adhesive layer 2 and the second adhesive layer 3 each have a crosslinked structure.

[0071] With this configuration, the first adhesive layer 2 and the second adhesive layer 3 have a dense structure. This dense structure improves the strength of the first adhesive layer 2, preventing damage to the wood sheet 31 in the evaluation process carried out after the manufacturing process. On the other hand, this dense structure allows the second adhesive layer 3 to prevent water vapor and impregnated resin contained in the wood material 4 from leaking out of the wood material 4.

[0072] The first adhesive layer 2 contains a blocked isocyanate-based curing agent, and has urethane bonds.

[0073] With this configuration, a cross-linked structure is formed in the first adhesive layer 2.

[0074] The first adhesive layer 2 has an average thickness of 3 μm or more and 100 μm or less, and the second adhesive layer 3 has an average thickness of 10 μm or more and 100 μm or less.

[0075] With this configuration, the first adhesive layer 2 has an average thickness of 3 μm or more, which improves the adhesion between the protective layer 1 and the second adhesive layer 3. The second adhesive layer 3 has an average thickness of 10 μm or more, which allows it to function as a barrier layer. Furthermore, the first adhesive layer 2 and the second adhesive layer 3 have an average thickness of 100 μm or less, which allows the manufacturing cost to be reduced, and furthermore, the flexibility of the wood material 4 can be maintained, improving the formability of the entire wood material sheet 31.

[0076] The wood sheet 31 further includes a release layer 52 disposed on the surface of the protective layer 1 opposite the first adhesive layer 2, and a base film 51 disposed on the surface of the release layer 52 opposite the protective layer 1. The protective layer 1 has a total thickness of 3 μm to 100 μm, and has a hard coat function and a UV cut function. At the interface between the release layer 52 and the protective layer 1, the release layer 52 and the base film 51 are removable from the protective layer 1.

[0077] With this configuration, the protective layer 1 is protected by the base film 51, so the uneven surface shape of the protective layer 1 formed by conforming to the surface of the wood material 4 is not crushed, and the wood material sheet 31 can be formed. The uneven surface shape of the protective layer 1 maintains the original texture and appearance of wood, and the wood material sheet 31 achieves a luxurious expression with excellent texture and design derived from the material.

[0078] Furthermore, since the thickness of the protective layer 1 is 3 μm or more, it can exert a protective function on the surface of the wooden material 4. Since the thickness is 100 μm or less, it improves the conformability to the uneven surface shape of the wooden material 4. Furthermore, since the protective layer 1 has a hard coat function and a UV cut function, the protective layer 1 protects the wooden material 4 from damage, deformation, deterioration due to ultraviolet rays, and the like.

[0079] [Manufacturing method] Next, a method for producing the wood sheet 31 will be described.

[0080] Fig. 3 is a cross-sectional view of the second adhesive layer 3 and the wood material 4. Fig. 4 is a cross-sectional view of the wood material sheet 31 before the thermocompression bonding process. Fig. 5 is a cross-sectional view of the wood material sheet during the thermocompression bonding process. In Fig. 5, the X direction along the cross-sectional direction and the Y direction perpendicular to the cross-sectional direction are indicated by arrows. Fig. 6 is a cross-sectional view of the wood material sheet after the thermocompression bonding process.

[0081] The manufacturing method of the wood sheet 31 includes step S11 of forming a first adhesive layer 2 on one side of the protective layer 1, step S12 of forming a second adhesive layer 3 on one side of the wood material 4, and step S14 of forming a laminate by thermocompression bonding. In step S14, the protective layer 1 with the first adhesive layer 2 arranged on the lower side, the wood material 4 with the second adhesive layer 3 arranged on the upper side, the thermoplastic shape-conforming layer 5, and the support layer 6 are laminated and thermocompression bonded in order from the top along the Y direction in Fig. 5.

[0082] First, a first adhesive layer 2 is formed on one surface of a protective layer 1 to form a transfer film 50 (step S11). The transfer film 50 may be formed as a sheet film, or may be formed as a continuous roll film to improve productivity.

[0083] 3, the second adhesive layer 3 is formed by applying in a liquid state to one surface of the wooden material 4 by a process such as spraying, roll coating, or inkjet coating (step S12). Since the second adhesive layer 3 is formed in a liquid state having fluidity, it can penetrate into the recess S3 between the protrusions S1 and S2 on the surface of the wooden material 4. Although the surface of the second adhesive layer 3 shown in FIG. 3 is flat, the surface of the second adhesive layer 3 may be wavy and curved along the contour of the wooden material 4.

[0084] Next, in order to harden the second adhesive layer 3, a process suitable for the adhesive base agent and the added hardener, such as heat hardening or UV hardening, is performed (step S13). The second adhesive layer 3 is hardened while infiltrated into the recess S3.

[0085] After step S13, the transfer film 50, the wood material 4, the thermoplastic shape-conforming layer 5, and the support layer 6 are arranged in this order, as shown in Fig. 4. The transfer film 50 is arranged so that the surface on which the first adhesive layer 2 is formed faces the surface on which the second adhesive layer 3 is formed of the wood material 4.

[0086] Next, as shown in FIG. 5, each layer is thermocompression bonded by a thermocompression bonding device N (step S14). The thermally melted first adhesive layer 2 bonds the protective layer 1 and the second adhesive layer 3 cured in step S13. Since the adhesive layers 2 and 3 are cured in different steps, a boundary 9 is formed between the first adhesive layer 2 and the second adhesive layer 3. In addition, the thermally melted thermoplastic shape-following layer 5 bonds the wood material 4 and the support layer 6. The surface unevenness of the wood material 4 is transferred by following the first adhesive layer 2 and the protective layer 1. In addition, the base film 51 prevents the protective layer 1 from directly touching the thermocompression bonding device N and protects it from the pressure, so the surface unevenness transferred to the protective layer 1 is not crushed in step S14. In step S14, a laminate of the wood material sheet 31, the peeling layer 52, and the base film 51 is formed.

[0087] During thermocompression bonding, water vapor is generated from inside the wood material 4, but since a barrier layer is formed on the surface of the wood material 4 by the hardened second adhesive layer 3, the outflow of water vapor in the Y direction on the protective layer 1 side is suppressed. Furthermore, since no air layer remains in the recess S3 after the formation of the second adhesive layer 3, there is no layer through which water vapor can move between the wood material 4 and the second adhesive layer 3 or on the surface of the wood material 4. Therefore, the movement of water vapor is limited to the X direction toward the end face of the wood material 4, and water vapor flows out from the end face. In addition, when an organic resin having a chain structure is impregnated inside the wood material 4, the second adhesive layer 3 is formed on the surface of the wood material 4 by the heat and pressure during the thermocompression bonding process, so that the seepage of the impregnated resin in the Y direction can be suppressed in the same way as water vapor. The seepage of the impregnated resin due to changes over time can also be suppressed in the same way. The movement of the impregnated resin is also limited to the X direction, like water vapor.

[0088] Next, as shown in FIG. 6, after the thermocompression bonding is completed, the release layer 52 and the base film 51 are removed from the wood sheet 31 at the interface with the protective layer 1, to obtain the wood sheet 31 (step S15).

[0089] [effect] The manufacturing method of the wood material sheet 31 according to the first embodiment has the following advantages.

[0090] The second adhesive layer 3 is formed by applying it in a liquid state to the surface of the wood material 4 .

[0091] In this manner, the second adhesive layer 3 in a liquid state can expel air from the recesses S3 on the surface of the wood material 4 in step S12, and no air layer is formed between the second adhesive layer 3 and the wood material 4.

[0092] The second adhesive layer 3 is cured prior to step S14 of forming the laminate.

[0093] By using such a method, the second adhesive layer 3 cured before step S14 can suppress the movement of water vapor and the impregnated resin toward the protective layer 1 during step S14, and can suppress the occurrence of bubbles due to water vapor, seepage of the impregnated resin, shininess, stickiness, and the like in the protective layer 1. This results in a wood sheet 31 with reduced appearance defects. Furthermore, the second adhesive layer 3 can suppress the occurrence of poor appearance in the completed wood sheet 31 due to seepage of the impregnated resin over time.

[0094] In the first embodiment, the release layer 52 is described as being made of a thermosetting melamine resin, a two-component curing urethane resin, a thermosetting silicone resin, etc. However, the present invention is not limited to these materials, and any material that can provide similar effects may be used.

[0095] In the first embodiment, when an after-cure type material is used for the protective layer 1, it is explained that the protective layer 1 is cured by irradiation with ultraviolet light and EB in the final process after the peeling layer 52 is peeled off. However, this order is not limited, and the protective layer 1 may be cured at an appropriate timing in the manufacturing process of the wood sheet 31 depending on the application.

[0096] In the first embodiment, the wooden material 4 is described as a single sheet of natural wood, but the present invention is not limited to this, and the wooden material 4 may be a processed sheet-shaped wooden board made by laminating a plurality of sheets of natural wood and slicing them to an average thickness of 0.1 mm or more and 2 mm or less. Also, the wooden material 4 may be made of parquet.

[0097] The first adhesive layer 2 and the second adhesive layer 3 may be formed of the same material. Even when the first adhesive layer 2 and the second adhesive layer 3 are formed of the same material, the boundary 9 is formed between the first adhesive layer 2 and the second adhesive layer 3 because the second adhesive layer 3 is cured before the thermocompression bonding step S14.

[0098] In the first embodiment, it has been described that the release layer 52 and the base film 51 are removed after the thermocompression bonding step S14. However, the release layer 52 and the base film 51 can be removed between any steps. Therefore, it is also possible to store the wood sheet 31 with the release layer 52 and the base film 51 attached without removing the release layer 52 and the base film 51.

[0099] In the first embodiment, an example in which the second adhesive layer 3 is formed on one surface of the wooden material 4 has been described, but the present invention is not limited to this. The second adhesive layer 3 may be provided on both surfaces of the wooden material 4. That is, the second adhesive layer 3 may be formed on the surface of the wooden material 4 on the second adhesive layer side and on the surface on the thermoplastic shape-conforming layer 5 side. In addition, the second adhesive layer 3 may be formed on one surface of the wooden material 4 and cured, and then the second adhesive layer 3 may be formed on the other surface and cured. Alternatively, the second adhesive layer 3 may be formed on both surfaces of the wooden material 4 at the same time by dipping or the like, and cured.

[0100] (Variation 1) Fig. 7 is a cross-sectional view of a wood sheet 31 in which a second adhesive layer 3 and a third adhesive layer 3A are formed on both sides of a wood material 4. As shown in Fig. 3, a third adhesive layer 3A is also provided between the wood material 4 and the thermoplastic shape-conforming layer 5, so that adhesive layers 3, 3A are provided on both sides of the wood material 4.

[0101] With this configuration, adhesive layers 3, 3A are formed on both sides of the wood material 4 as barrier layers, and water vapor and impregnated resin of the wood material 4 emitted from the wood material 4 during the thermocompression bonding process can more easily escape from the end faces of the wood material 4. The occurrence of convex bubbles, seepage, stickiness, greasiness, etc. on the surface of the protective layer 1 can be further suppressed.

[0102] (Embodiment 2) A molded product 71 according to embodiment 2 of the present disclosure will be described. Note that in embodiment 2, differences from embodiment 1 will be mainly described. In embodiment 2, configurations that are the same as or similar to embodiment 1 are given the same reference numerals, and duplicated descriptions will be omitted.

[0103] FIG. 8 is a schematic cross-sectional view showing a cross-sectional structure of a molded product 71 using a wood material sheet 31 according to the second embodiment of the present disclosure.

[0104] The molded product 71 of embodiment 2 differs from the wood sheet 31 of embodiment 1 in that it has a fourth adhesive layer 7 and a resin casing 8 on the side of the support layer 6 opposite the thermoplastic shape-conforming layer 5.

[0105] The fourth adhesive layer 7 and the resin housing 8 are integrated on the support layer 6 side of the wood sheet 31 by, for example, vacuum pressure molding or insert molding to form a molded product 71. In the second embodiment, the fourth adhesive layer 7 and the resin housing 8 are formed on the wood sheet 31 before the base film 51 and the release layer 52 are removed.

[0106] <4th adhesive layer> The fourth adhesive layer 7 bonds the support layer 6 and the resin housing 8. For example, the fourth adhesive layer 7 may be composed of either a thermoplastic adhesive such as a coating type or a sheet type adhesive, or a thermosetting adhesive. The average thickness of the fourth adhesive layer 7 may be, for example, 1 μm or more and 100 μm or less.

[0107] <Plastic housing>

[0108] The resin housing 8 serves to improve the strength of the wood sheet 31. The resin housing 8 is made of general-purpose molding resin such as PMMA resin, ABS resin, PS resin, PC resin, etc. The resin housing 8 may also be made of resin that requires molding at high temperatures, such as resin for optical applications or super engineering resin.

[0109] In the method for manufacturing molded product 71, after steps S11 to S15 of the first embodiment are performed, a resin casing 8 is formed on the support layer 6 side of the laminate (step S16). The resin casing 8 may be injection molded in advance, and then attached to the support layer 6 side of the laminate in step S16, or the resin casing 8 may be injection molded directly onto the support layer 6 side of the laminate.

[0110] [effect] According to the molded product 71 of the second embodiment, the following effects can be obtained.

[0111] The molded product 71 has a wood sheet 31 and a resin housing 8 arranged on the support layer 6 side of the wood sheet 31 .

[0112] With such a configuration, the strength of the molded product 71 can be improved.

[0113] The manufacturing method of the molded product 71 includes a step of manufacturing the wood material sheet 31 according to the above-mentioned manufacturing method, and then forming the resin housing 8 on the support layer 6 side of the laminate.

[0114] By such a method, a molded product 71 having a resin housing 8 can be formed.

[0115] In the second embodiment, the wood sheet 31 and the resin housing 8 are integrated together. However, the wood sheet 31 of the first embodiment can be attached as a single sheet like wallpaper.

[0116] In the second embodiment, an example has been described in which the resin housing 8 is made of a general-purpose molding resin, but other materials may be used as long as they have the required strength.

[0117] In the second embodiment, the molded article 71 having the fourth adhesive layer 7 is described as an example, but is not limited thereto. For example, when insert molding is performed using a member having a fiber layer such as a nonwoven fabric for the support layer 6, an anchor effect is generated by the molding resin penetrating into the gaps between the fibers, and the molded article 71 can be formed without forming the fourth adhesive layer 7.

[0118] In the second embodiment, the wood sheet 31 is integrated with the plastic housing 8 without removing the release layer 52 and the base film 51, but the present invention is not limited to this. When integrating the wood sheet 31 with the plastic housing 8, the removal of the release layer 52 and the base film 51 can be selected arbitrarily depending on the application.

[0119] Although the present disclosure has been fully described in connection with the preferred embodiments with reference to the accompanying drawings, various changes and modifications will be apparent to those skilled in the art, and such changes and modifications should be understood to be included within the scope of the present disclosure as defined by the appended claims unless they depart therefrom. [Industrial Applicability]

[0120] The wood sheets and molded products of the present disclosure are useful for decorating the exteriors of home appliances and the interiors of vehicles. [Explanation of symbols]

[0121] 1 protective layer 2 First adhesive layer 3 Second adhesive layer 3A 3rd adhesive layer 4 Wood material 5 Thermoplastic shape-conforming layer 6 Support layer 7 4th adhesive layer 8 Plastic housing 9 boundaries 31 Wood Sheet 50 Transfer Film 51 Base Film 52 Peeling layer 71 Molded products

Claims

1. Natural wood materials and A protective layer disposed on one surface of the wood material; A support layer disposed on the other surface of the wood material; a first adhesive layer provided on a surface of the protective layer facing the wood material and containing a blocked isocyanate-based curing agent; A second adhesive layer provided between the first adhesive layer and the wood material; A thermoplastic shape-conforming layer provided between the wood material and the support layer; Equipped with the first adhesive layer and the second adhesive layer are not integral with each other, and there is a boundary between the first adhesive layer and the second adhesive layer; The first adhesive layer has a urethane bond.

2. The wood material has an uneven surface, The second adhesive layer penetrates into the recesses of the surface irregularities of the wood material, The wood sheet according to claim 1 , wherein there is no air gap between the second adhesive layer and the uneven surface shape of the wood material.

3. The wood sheet according to claim 1 or 2, wherein the second adhesive layer has a cross-linked structure.

4. The first adhesive layer has an average thickness of 3 μm or more and 100 μm or less, The wood sheet according to claim 1 , wherein the average thickness of the second adhesive layer is 10 μm or more and 100 μm or less.

5. a release layer disposed on a surface of the protective layer opposite to the first adhesive layer; a base film disposed on a surface of the release layer opposite to the protective layer; Further equipped with the protective layer has a total thickness of 3 μm or more and 100 μm or less, and has a hard coat function and a UV cut function; 5. The wood sheet according to claim 1, wherein the release layer and the base film are removable from the protective layer at the interface between the release layer and the protective layer.

6. 6. Wood sheet according to claim 1, further comprising a third adhesive layer between the wood and the thermoplastic shape conforming layer.

7. The wood sheet according to any one of claims 1 to 6, A resin housing arranged on the support layer side of the wood sheet; A molded article having the above structure.

8. forming a first adhesive layer containing a blocked isocyanate-based curing agent on one surface of a protective layer; forming a second adhesive layer on one surface of the wood material; a step of laminating the protective layer, the wooden material in which the second adhesive layer is disposed opposite the first adhesive layer formed on the protective layer, a thermoplastic shape-conforming layer disposed opposite the other surface of the wooden material, and a support layer in that order, and thermocompressing the layers to form a laminate; Including, The method for manufacturing a wood sheet, wherein the first adhesive layer has a urethane bond.

9. The method for manufacturing a wood sheet according to claim 8 , wherein the second adhesive layer is formed by applying the second adhesive layer in a liquid state to the surface of the wood material.

10. The method for producing a wood sheet according to claim 8 or 9, wherein the second adhesive layer is cured before the step of forming the laminate.

11. forming a first adhesive layer containing a blocked isocyanate-based curing agent on one surface of a protective layer; forming a second adhesive layer on one surface of the wood material; a step of laminating the protective layer, the wooden material in which the second adhesive layer is disposed opposite the first adhesive layer formed on the protective layer, a thermoplastic shape-conforming layer disposed opposite the other surface of the wooden material, and a support layer in that order, and thermocompressing the layers to form a laminate; forming a resin housing on the support layer side of the laminate; Including, The method for producing a molded article, wherein the first adhesive layer has a urethane bond.

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