Composite body and method for manufacturing same

Abstract

A composite body (1) according to the present invention is composed of an integrated product in which an aluminum-containing base part (2) and a design layer (6) are joined via an intermediate layer (4). The intermediate layer (4) is composed of a wood block aggregate impregnated with resin or a wood plate impregnated with resin, and the surface of the base part on the intermediate-layer side is provided with a plurality of overhang parts. The resin is preferably contained in the cell wall of the wood block or the wood plate.

Description

Composite and manufacturing method thereof

[0001] The present invention relates to a composite body having an aluminum-containing base and an intermediate layer that has excellent adhesion to a decorative layer, and a method for producing the same.

[0002] A known technology for producing wood-based molded articles with a wood-like texture is to process sustainably available wood logs, waste wood, or recycled materials into powder, fibers, chips, etc., and then place them together with a resin or a precursor thereof in a mold cavity and perform compression molding under heated conditions. Composites obtained by integrating such wood-based molded articles with substrates made of metal or the like, as necessary, are used in vehicle interior materials, fixtures such as furniture, and building materials such as flooring and wall materials.

[0003] The following techniques are known for composites with a wood-like texture or methods for producing such composites. Patent Document 1 discloses a wood decorative board comprising a metal substrate on one side of which a fiber-reinforced synthetic resin layer containing dispersed wood chips is provided, a coating film made of unsaturated polyester resin is provided on the fiber-reinforced synthetic resin layer, and a fiber-reinforced synthetic resin layer is provided on the other side of the metal substrate. Patent Document 1 also discloses a method for producing a wood decorative board in which a metal substrate is placed on a fiber substrate impregnated with uncured synthetic resin, a composite substrate containing dispersed wood chips on the reinforcing fiber substrate impregnated with uncured synthetic resin is placed on the metal substrate, and the resulting mixture is heated and pressurized to cure the resin and obtain an integrated product, after which an unsaturated polyester resin paint is applied to the integrated composite substrate. Patent Document 2 discloses a method for producing a composite material in which highly flexible synthetic resin is impregnated into wood by vacuum or vacuum pressure, and the impregnated resin is then layered on a backing material without using an adhesive while still unhardened. Heat is applied while the wood is curved and punched, and the synthetic resin impregnated into the wood reacts and hardens, while at the same time the resin that flows out of the wood bonds the wood to the backing material, thereby producing a composite material.

[0004] Patent Document 3 discloses a joining member in which a wood-based material and a non-wood-based material having recesses and / or protrusions on their surfaces are joined and integrated, wherein the wood-based material penetrates into the recesses or surrounds the protrusions of the non-wood-based material, filling them with a state in which the relative positions of the wood fiber cells have changed. Patent Document 4 also discloses a non-flammable wood composite material comprising a first wood material having a thickness of 2 to 4 mm and containing a flame retardant, an inorganic substrate or a second wood material, and an adhesive layer interposed between the first wood material and the inorganic substrate or the second wood material, wherein the flame retardant contains a first compound having a hydroxyl group, and the adhesive layer is made of an adhesive containing a second compound having a hydroxyl group or an aqueous material. Patent Document 4 also discloses a method for producing a non-flammable wood composite material, in which a first wood material having a thickness in the range of 2 to 4 mm and containing a flame retardant agent is bonded to an inorganic substrate or a second wood material using an adhesive, in which the flame retardant agent contains a first compound having a hydroxyl group, and the adhesive contains a second compound having a hydroxyl group or an aqueous material, and the adhesive is cured to form an adhesive layer to produce the non-flammable wood composite material.

[0005] Patent Document 5 proposes surface modification of a metal substrate (forming an oxide film or increasing the surface area) to improve adhesion when adhering an organic polymeric substance to the surface of the substrate. Specifically, the method for treating a metal surface comprises a first step of chemical etching the metal surface to form a film, and a second step of chemically removing the film formed on the metal surface by the first step. In Example 1 of Patent Document 1, an aluminum plate, which is a metal substrate, is surface-treated (forming a chromium phosphate film) before the wood veneer is manufactured.

[0006] JP 3-239543, JP 10-113906, JP 2021-88059, JP 2022-7386, JP 11-293476

[0007] The object of the present invention is to provide a composite having a base containing aluminum, an intermediate layer containing a wood material, and a decorative layer, which has excellent adhesion between the base and the intermediate layer, and between the decorative layer and the intermediate layer, and which has excellent structural stability as a multilayer body, and a method for manufacturing the composite.

[0008] The inventors have discovered that by placing an assembly of resin-impregnated wood chips (chipped wood material) or a resin-impregnated wooden board on an aluminum-containing roughened substrate having an overhang, and then placing a decorative material on top of that, and hot-pressing the resulting load, a composite can be obtained that comprises an aluminum-containing base, an intermediate layer derived from the above-mentioned assembly of resin-impregnated wood chips (chipped wood material) or the resin-impregnated wooden board, and a decorative layer, and that has excellent adhesion between the base and the intermediate layer and between the decorative layer and the intermediate layer, and that has excellent structural stability as a multilayer body.

[0009] The present invention is described below. (1) A composite comprising an integrated body in which an aluminum-containing base and a decorative layer are joined via an intermediate layer, wherein the intermediate layer is made of an aggregate of resin-impregnated wood chips or a resin-impregnated wood board, and the surface of the base on the intermediate layer side has a plurality of overhanging portions. (2) The composite according to (1), in which the resin is also contained in the cell walls of the wood chips or wood board. (3) The composite according to (1), in which the resin is derived from at least one resin selected from melamine resin, phenolic resin, urea resin, acrylic resin, styrene-based resin, and urethane resin. (4) The composite according to (1), in which the thickness of the intermediate layer is 0.1 to 20 mm. (5) The composite according to (1), in which the decorative layer comprises a thin wood body. (6) The composite according to (1), in which the overhanging portions are formed by subjecting the surface of an article containing metallic aluminum or an aluminum alloy to acid treatment, electric discharge machining, shot blasting, or electrolytic etching. (7) A method for producing the composite described in (1) above, comprising the steps of: subjecting a substrate containing metallic aluminum or an aluminum alloy to acid treatment, electric discharge machining treatment, shot blasting treatment, or electrolytic etching treatment to form a plurality of overhang portions on the surface of the substrate to produce an aluminum-containing roughened substrate; crushing resin-component-impregnated wood, which is wood impregnated with a resin component containing at least one selected from a thermoplastic resin precursor and a thermosetting resin, to produce resin-component-containing crushed wood; placing the resin-component-containing crushed wood on the surface of the aluminum-containing roughened substrate having the overhang portions to produce a first load; placing a decorative material on the layer of resin-component-containing crushed wood in the first load to produce a second load; and subjecting the second load to hot pressing. (8) The method for producing a composite described in (7) above, in which the thermoplastic resin is a urethane resin. (9) The method for producing a composite according to (7) above, wherein the thermosetting resin comprises at least one selected from the group consisting of melamine resin, phenolic resin, urea resin, and urethane resin. (10) The method for producing a composite according to (7) above, wherein the resin component-containing crushed wood material has a major axis of 0.05 to 10 mm.(11) A method for producing the composite described in (1) above, comprising the steps of: subjecting a substrate containing metallic aluminum or an aluminum alloy to acid treatment, electric discharge machining treatment, shot blasting treatment, or electrolytic etching treatment to form a plurality of overhang portions on the surface of the substrate to produce an aluminum-containing roughened substrate; producing a resin-component-impregnated wooden board by impregnating a wooden board with a resin component containing at least one selected from a thermoplastic resin precursor and a thermosetting resin; placing the resin-component-impregnated wooden board on the surface of the aluminum-containing roughened substrate having the overhang portions to produce a third load; placing a decorative material on the resin-component-impregnated wooden board in the third load to produce a fourth load; and subjecting the fourth load to hot pressing. (12) The method for producing a composite described in (11) above, wherein the thermoplastic resin is a urethane resin. (13) The method for producing a composite according to (11) above, wherein the thermosetting resin comprises at least one selected from the group consisting of melamine resin, phenolic resin, and urea resin. (14) The method for producing a composite according to (11) above, wherein the thickness of the resin-component-impregnated wooden board is 0.01 to 20 mm. (15) The method for producing a composite according to (7) or (11) above, wherein the decorative material comprises a thin-walled piece of wood.

[0010] The composite of the present invention has excellent adhesion between the aluminum-containing base and intermediate layer, and between the decorative layer and intermediate layer, resulting in excellent structural stability as a multilayer body. When the decorative layer is derived from wood, the composite can have a clear wood grain, etc. Because the base can serve as a support, the composite can be suitably used as building materials and architectural components, furniture and furnishings, vehicle components, home appliance parts, daily necessities, and the like, which have excellent appearances due to the decorative layer. The composite manufacturing method of the present invention allows for efficient manufacturing of composites that exhibit the above-mentioned effects.

[0011] FIG. 1 is a schematic diagram showing the cross-sectional structure of a composite of the present invention. FIG. 2 is a schematic diagram illustrating the cross-sectional shape of an overhang portion formed on the surface of an intermediate layer side of an aluminum-containing base that constitutes a composite of the present invention. FIG. 3 is a schematic cross-sectional view showing an example of the outermost surface of an aluminum-containing roughened substrate used in producing a composite of the present invention. FIG. 4 is a cross-sectional image showing the outermost surface of a metal aluminum plate before surface treatment before roughening in [Example]. FIG. 5 is a cross-sectional image showing the outermost surface of a metal aluminum plate that has been acid-treated in [Example]. FIG. 6 is a cross-sectional image showing the outermost surface of an aluminum alloy plate (ADC12) that has been acid-treated in [Example]. FIG. 7 is a cross-sectional image showing the outermost surface of an aluminum alloy plate (AC4CH) that has been acid-treated in [Example]. FIG. 8 is a cross-sectional image showing the outermost surface of a metal aluminum plate that has been electric discharge machined in [Example]. FIG. 9 is a cross-sectional image showing the outermost surface of an aluminum alloy plate (ADC12) that has been shot blasted in [Example]. FIG. 10 is a cross-sectional image showing the outermost surface of a sanded metal aluminum plate in [Example]. FIG. 11 is an external appearance image of a composite obtained in Example 1. FIG. 12 is a cross-sectional image of a composite obtained in Example 1. FIG. 13 is an enlarged image of the interface between the base and intermediate layer of a composite obtained in Example 1. 1 is an image showing the appearance of the composite obtained in Example 3.

[0012] The composite of the present invention is an integrated product formed by joining an aluminum-containing base and a decorative layer via an intermediate layer, the intermediate layer being an aggregate of resin-impregnated wood chips or a resin-impregnated wood board, and characterized in that the surface of the base on the intermediate layer side has a plurality of overhang portions. Figure 1 is a schematic diagram showing the cross-sectional structure of the composite 1 of the present invention, and although the overhang portions are not shown, the surface of the base 2 has an intermediate layer 4 and a decorative layer 6, in that order.

[0013] In the composite of the present invention, the base 2 including the overhang portion contains aluminum element, and is preferably mainly composed of metallic aluminum or an aluminum alloy, and may further contain an aluminum compound such as aluminum oxide. The overhang portion and the remaining base main body portion may be made of different aluminum components.

[0014] The base 2 essentially functions as a support. The shape of the base 2 is not particularly limited, and may be plate-like, linear (rod-like), block-like, ring-like, or the like, and may be thin-walled or thick-walled. In the present invention, the surface of the base 2 on the side of the intermediate layer 4 is provided with a plurality of overhanging portions, so that the surface of the base 2 is rough, but the overall surface of the base 2 is usually flat or uneven (including wavy and jagged patterns).

[0015] The overhang portion according to the present invention has a shape that protrudes obliquely from the surface of the base 2, or extends from the surface of the base 2 in a direction perpendicular to the base 2 while bending at its tip, with a recessed portion between the protruding tip and the base 2. The cross-sectional structure of the overhang portion is not particularly limited, but examples are shown in FIGS. 2A and 2B . FIG. 2A is a schematic diagram showing an overhang portion 8 having a recessed portion 9 below the protruding tip on the base 2 side, and FIG. 2B is a schematic diagram showing multiple (two) overhang portions 8 on one convex portion. The size of the overhang portion 8 (e.g., height from the surface of the base 2, width from the protruding tip to the base of the recessed portion 9, etc.) is not particularly limited. The protruding tip may be needle-shaped, tapered plate-shaped, or the like.

[0016] The number of overhangs on the surface of the base 2 is not particularly limited, but from the viewpoint of the adhesiveness between the intermediate layer 4 and the base 2, it is preferably 10 to 10,000 per 1 mm. ２ , more preferably 100 to 10,000 pieces / 1 mm ２ is.

[0017] The overhang portion 8 is preferably formed by subjecting the surface of the article containing metallic aluminum or an aluminum alloy to an acid treatment, an electric discharge treatment, a shot blasting treatment, or an electrolytic etching treatment. The acid treatment, the electric discharge treatment, the shot blasting treatment, and the electrolytic etching treatment will be described later.

[0018] The intermediate layer 4 is made of at least one of a resin-impregnated assembly of wood chips and a resin-impregnated wooden board. The resin contained in the intermediate layer 4 is not particularly limited as long as it has adhesive properties to the article, but is preferably derived from at least one of a thermosetting resin and a thermoplastic resin. Therefore, the resin contained in the intermediate layer 4 is usually at least one of a cured resin and a thermoplastic resin.

[0019] Examples of thermosetting resins include melamine resins, phenolic resins, urea resins, urethane resins, unsaturated polyesters, diallyl phthalate, silicone resins, vinyl ester resins, and polyimide resins. Of these, melamine resins, phenolic resins, urea resins, and urethane resins are preferred from the viewpoint of adhesiveness. Examples of thermoplastic resins include acrylic resins, olefinic resins, styrene-based resins, polyesters, polyamide resins, urethane resins, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, polytetrafluoroethylene, polyacetal, polycarbonate, polyphenylene ether, polyphenylene sulfide, polysulfone, polyether sulfone, polyarylate, polyether ether ketone, polyimide, and polyamide imide. Of these, acrylic resins, styrene-based resins, and urethane resins are preferred from the viewpoint of adhesiveness.

[0020] The wood chips or wood boards contained in the intermediate layer 4 are derived from plants having cell walls, such as wood (conifers such as cedar, cypress, and pine; broad-leaved trees such as poplar, beech, oak, and birch), bamboo, flax (jute, kenaf, flax, hemp, ramie, and sisal), and herbs. They may be the plant itself (sawn board, veneer, wood chips, powder, fiber, etc.), waste wood, or chemically processed products thereof. The intermediate layer 4 may contain wood chips or wood boards from multiple tree species. In the present invention, veneer, veneer, wood chips, powder, and fiber are preferred from the viewpoint of resin impregnation. Furthermore, in the intermediate layer 4, it is preferable that a portion of the resin is contained within the cell walls of the wood chips or wood boards.

[0021] The shape and size of the wood pieces contained in the intermediate layer 4 are not particularly limited. The wood pieces may be either regular-shaped or irregular-shaped, and their major diameter is preferably 0.05 to 10 mm, more preferably 0.05 to 5 mm. The shape and size of the wooden board contained in the intermediate layer 4 are also not particularly limited. The thickness of the wooden board is preferably 0.01 to 20 mm, more preferably 0.05 to 5 mm.

[0022] The content ratios (mass ratios) of the wood chips and resin contained in the intermediate layer 4, when the total of both is taken as 100% by mass, are preferably 5 to 95% by mass and 5 to 95% by mass, more preferably 10 to 90% by mass and 10 to 90% by mass, and even more preferably 20 to 80% by mass and 20 to 80% by mass, respectively. Furthermore, the content ratios (mass ratios) of the wood board and resin contained in the intermediate layer 4, when the total of both is taken as 100% by mass, are preferably 5 to 95% by mass and 5 to 95% by mass, more preferably 10 to 90% by mass and 10 to 90% by mass, and even more preferably 20 to 80% by mass and 20 to 80% by mass, respectively. When the content ratios of the wood chips or wood board and resin are within the above ranges, excellent adhesion is achieved between the intermediate layer 4 and the base 2 or the decorative layer 6. Furthermore, since the composite of the present invention includes an overhang portion 8 on the surface of the base 2, the preferred configuration of the intermediate layer 4 described above provides particularly excellent structural stability of the composite.

[0023] The thickness of the intermediate layer 4 is selected appropriately depending on the type, application, etc. of the composite of the present invention, but is usually 0.01 to 20 mm, preferably 0.05 to 5 mm. From the viewpoint of adhesion between the intermediate layer 4 and the base 2 or the decorative layer 6, it is preferable that the resin is contained throughout the entire intermediate layer 4, but depending on the shape, thickness, etc. of the intermediate layer 4, the resin may be contained only on the interface side of the intermediate layer 4 with the base 2 and the decorative layer 6.

[0024] The design layer 6 is provided to impart design to the composite of the present invention. The design layer 6 may be either a single-layer or multi-layer type. The constituent material of the design layer 6 is not particularly limited, and may be a thin wooden body, i.e., a thin wooden body obtained by processing wood, a resin film, paper, a wooden board, or the like, all of which exhibit good adhesion to the intermediate layer 4. In the present invention, the design layer 6 preferably includes a thin wooden body, and in this case, the outermost surface of the design layer 6 may be provided with a transparent protective film layer, a paint layer, or the like.

[0025] The composite of the present invention can be manufactured using an aluminum-containing substrate with an overhang for the base 2, at least one of wood chips (crushed wood, etc.) and wood boards for the intermediate layer 4, a resin component (a thermoplastic resin precursor or a thermosetting resin) to be impregnated into the wood chips and wood boards, and a decorative material for the decorative layer 6.

[0026] Next, a method for producing the composite of the present invention will be described. One embodiment of the composite production method of the present invention (hereinafter referred to as the "first production method") includes a step of subjecting a substrate containing metallic aluminum or an aluminum alloy (hereinafter referred to as the "aluminum substrate") to an acid treatment, an electric discharge treatment, a shot blasting treatment, or an electrolytic etching treatment to form a plurality of overhang portions on the surface of the aluminum substrate to produce an aluminum-containing roughened substrate (hereinafter referred to as the "aluminum-containing roughened substrate production step"); and a step of impregnating wood with a resin component containing at least one selected from a thermoplastic resin precursor (hereinafter also referred to as a "precursor composition") and a thermosetting resin. The method sequentially comprises a step of crushing resin-component-impregnated wood to produce resin-component-containing crushed wood material (hereinafter referred to as the "resin-component-containing crushed wood material production step"), a step of placing the resin-component-containing crushed wood material on the surface of the aluminum-containing roughened base material having the overhanging portion to produce a first load (hereinafter referred to as the "first load material production step"), a step of placing a decorative material on the resin-component-containing crushed wood material layer in the first load to produce a second load (hereinafter referred to as the "second load material production step"), and a step of subjecting the second load to hot pressing (hereinafter referred to as the "first hot pressing step").

[0027] In addition, another aspect of the composite manufacturing method of the present invention (hereinafter referred to as the "second manufacturing method") sequentially includes the same aluminum-containing roughened substrate manufacturing step as in the first manufacturing method, a step of manufacturing a resin component-impregnated wooden board by impregnating a wooden board with a resin component containing at least one selected from a precursor (precursor composition) of a thermoplastic resin and a thermosetting resin (hereinafter referred to as the "resin component-impregnated wooden board manufacturing step"), a step of placing the resin component-impregnated wooden board on the surface having the overhang portion of the aluminum-containing roughened substrate to manufacture a third loaded object (hereinafter referred to as the "third loaded object manufacturing step"), a step of placing a decorative material on the resin component-impregnated wooden board in the third loaded object to manufacture a fourth loaded object (hereinafter referred to as the "fourth loaded object manufacturing step"), and a step of subjecting the fourth loaded object to hot pressing (hereinafter referred to as the "second hot pressing step").

[0028] In the present invention, the aluminum-containing roughened substrate preparation step according to the first and second production methods is a step of subjecting an aluminum substrate to an acid treatment, an electric discharge treatment, a shot blasting treatment, or an electrolytic etching treatment to form a plurality of overhang portions 8 on the surface of the aluminum substrate, thereby preparing an aluminum-containing roughened substrate 10 (see FIG. 3 ).

[0029] An example of an acid treatment method for an aluminum substrate is a method of contacting the aluminum substrate with an acid aqueous solution. The acid aqueous solution is not particularly limited and can be one consisting of at least one inorganic acid and organic acid and water. Examples of inorganic acids include hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, and phosphoric acid. Examples of organic acids include acetic acid and citric acid. From the viewpoint of overhang formation, the pH of the acid aqueous solution is preferably 6 or less, more preferably 3 or less. The contact time between such an acid aqueous solution and the aluminum substrate is preferably 1 to 10 minutes, more preferably 3 to 10 minutes, when using an acid aqueous solution at 25°C, for example.

[0030] An example of a method for electrical discharge machining of an aluminum substrate is a method in which a voltage is applied between the aluminum substrate and an electrode in an insulating working fluid. The insulating working fluid is not particularly limited, and insulating liquids such as water and oil can be used. The electrode material is also not particularly limited, and can be conductive, such as copper, brass, tungsten, and graphite. Furthermore, the size and shape of the electrode are not limited, and wire, rod, tube, bulk, etc. can be used.

[0031] An example of a shot blasting method for an aluminum substrate is a method in which particles known as shot media are collided with the surface of the aluminum substrate. Examples of shot media include iron-based particles, stainless steel-based particles, aluminum-based particles, zinc particles, copper particles, glass beads, ceramic particles (alumina particles, silicon carbide particles, silicon nitride particles, zirconia particles, etc.), and resin particles. The particle size of the shot media is not particularly limited, but is typically 10 to 4000 μm, and preferably 100 to 2000 μm.

[0032] In the aluminum-containing roughened substrate preparation step, when acid treatment, electrical discharge machining treatment, shot blasting treatment, or electrolytic etching treatment is performed, multiple overhang portions are formed, and an aluminum oxide layer may be formed on the surface of the obtained aluminum-containing roughened substrate, or the overhang portions may be made of aluminum oxide. In the present invention, even if the state of aluminum on the surface of the aluminum-containing roughened substrate after each of the above surface treatments is not the same as before the surface treatment, the substrate can be directly proceeded to the first load preparation step (in the case of the first production method) or the third load preparation step (in the case of the second production method).

[0033] The resin component-containing crushed wood product preparation step in the first manufacturing method is a step of crushing resin component-impregnated wood, which is wood impregnated with a resin component containing at least one selected from a precursor composition and a thermosetting resin, to prepare resin component-containing crushed wood. When the resin component is a thermoplastic resin precursor (precursor composition), the resin component-impregnated wood is precursor composition-impregnated wood, which can be crushed as is to prepare precursor composition-containing crushed wood, which is resin component-containing crushed wood. When the resin component is a thermosetting resin, the resin component-impregnated wood is thermosetting resin-impregnated wood, which can be crushed while the thermosetting resin is uncured to prepare thermosetting resin-containing crushed wood, which is resin component-containing crushed wood.

[0034] The wood used in the first manufacturing method may be either a coniferous or broad-leaved tree, and the wood used in the resin-component-containing crushed wood product preparation step may be either a shaped or irregularly shaped piece. Furthermore, the wood may be from multiple tree species. Since multiple pieces of resin-component-containing crushed wood are typically used in the first load preparation step, it is preferable that they are uniform in shape or have minimal size variation. To obtain such resin-component-containing crushed wood, the wood used in the resin-component-containing crushed wood product preparation step is preferably a shaped piece. In this case, for example, the wooden board may be made of a coniferous or broad-leaved tree and obtained by cutting or milling lumber. The shape and size of the wooden board are not particularly limited, but from the viewpoint of impregnation of the precursor composition or thermosetting resin into the wooden board, the thickness of the wooden board is preferably 0.5 to 10 mm, more preferably 1 to 5 mm. The coniferous and broad-leaved trees listed above can be used.

[0035] The resin-impregnated wood is obtained by impregnating wood with at least one material selected from a precursor composition and a thermosetting resin.

[0036] For example, thermosetting resin-impregnated wood may be wood impregnated with only a thermosetting resin, or wood impregnated with a thermosetting resin and a curing agent, or wood impregnated with a thermosetting resin and a thermoplastic resin, or wood impregnated with a thermosetting resin and a precursor composition.

[0037] The thermosetting resin is preferably a melamine resin, a phenolic resin, a urea resin, or a urethane resin, more preferably a melamine resin. The content of the thermosetting resin in the thermosetting resin-impregnated wood, or the total content of the thermosetting resin and the curing agent, is preferably 5 to 1,900 parts by mass, more preferably 11 to 900 parts by mass, based on 100 parts by mass of the wood.

[0038] In the present invention, the combined use of a thermosetting resin and a thermoplastic resin precursor (precursor composition) is a preferred method for forming an intermediate layer that firmly bonds an aluminum-containing roughened substrate and a decorative material. Examples of the thermoplastic resin precursor (precursor composition) include a precursor composition of a urethane resin, which is a thermoplastic resin. This precursor composition is preferably a composition containing a blocked isocyanate compound and polyethylene glycol (hereinafter referred to as a "urethane resin-forming composition").

[0039] The blocked isocyanate compound is preferably formed from an isocyanate compound and a blocking agent that protects the isocyanate group contained in the isocyanate compound, and is inactivated by a group derived from the blocking agent. In the present invention, the blocked isocyanate compound is more preferably a compound that can be deblocked by heating at a temperature of 40°C to 200°C, i.e., the group derived from the blocking agent dissociates to produce the isocyanate compound. Furthermore, a particularly preferred blocked isocyanate compound is a compound that forms a thermoplastic polyurethane by reacting the deblocked blocked isocyanate compound with the ethylene glycol.

[0040] The isocyanate compound is not particularly limited as long as it has an isocyanate group, but the number of isocyanate groups contained is preferably 1 to 5, more preferably 1 to 2, and particularly preferably 1. The isocyanate compound may have other functional groups in addition to the isocyanate group, such as a (meth)acryloyloxy group.

[0041] Examples of the blocking agent include oximes such as formamidoxime, acetaldoxime, acetoxime, methyl ethyl ketoxime, diacetyl monooxime, benzophenone oxime, and cyclohexanone oxime; active methylenes such as dimethyl malonate, diethyl malonate, ethyl acetoacetate, methyl acetoacetate, and acetylacetone; lactams such as ε-caprolactam, δ-valerolactam, γ-butyrolactam, and β-propiolactam; phenols such as phenol, cresol, resorcinol, and xylenol; and alcohols such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol, tert-butyl alcohol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, and benzyl alcohol.

[0042] The blocked isocyanate compound is particularly preferably a compound having one -N(H)CO as a structure before being deblocked by heating, and having a group derived from a blocking agent bonded to the C atom of this -N(H)CO. For example, when the blocking agent is methyl ethyl ketoxime, a -O-N=C(CH ３ ) C ２ H ５ is a compound having a (meth)acryloyloxy group bonded thereto. Furthermore, as described above, the blocked isocyanate compound that can be deblocked to produce the isocyanate compound having another functional group, such as a (meth)acryloyloxy group, of the preferred embodiment, preferably has a (meth)acryloyloxy group. By using such a blocked isocyanate compound having a (meth)acryloyloxy group, it is possible to obtain thermosetting resin-impregnated wood in which thermoplastic polyurethane and thermosetting resin are contained in the cell walls of the wood.

[0043] The blocked isocyanate compound is particularly preferably 2-[0-(1'-methylpropylideneamino)carboxyamino]ethyl methacrylate, because it is liquid at room temperature, easily penetrates into the cell walls of wood, and can generate an isocyanate compound at 200°C or less, which does not decompose wood.

[0044] The polyethylene glycol is preferably a compound represented by the following general formula (1): HO—(CH ２ -CH ２ -O) ｎ —H (1) In the above general formula (1), n ​​is preferably 1 to 12,000, more preferably 4 to 500, and even more preferably 10 to 450, from the viewpoint of penetration into wood cell walls.

[0045] In the urethane resin-forming composition, the content ratios of the blocked isocyanate compound and polyethylene glycol can be appropriately set depending on the number of isocyanate groups contained in the isocyanate compound generated from the blocked isocyanate compound. In the present invention, when the total of the blocked isocyanate compound and polyethylene glycol is taken as 100% by mass, the content ratios are preferably 5 to 95% by mass and 5 to 95% by mass, more preferably 20 to 80% by mass and 20 to 80% by mass, and even more preferably 35 to 65% by mass and 35 to 65% by mass, respectively.

[0046] The urethane resin-forming composition may consist solely of a blocked isocyanate compound and polyethylene glycol, or may further contain other materials such as a liquid medium such as water or an organic solvent, an antioxidant, a heat stabilizer, a plasticizer, and the like.

[0047] In the present invention, when the urethane resin-forming composition, which is a precursor composition, is used in combination with a thermosetting resin, the total amount of the blocked isocyanate compound and polyethylene glycol used is preferably 5 to 2,000 parts by mass, and more preferably 20 to 1,000 parts by mass, relative to 100 parts by mass of the amount of the thermosetting resin used, or the total amount of the thermosetting resin and the curing agent used.

[0048] The precursor composition-impregnated wood is preferably a wooden board or piece impregnated with the urethane resin-forming composition as the precursor composition.

[0049] The method for producing resin-impregnated wood is not particularly limited, and can be a method in which wood is brought into contact with a precursor composition or a thermosetting resin. The contact conditions are appropriately set depending on the types of precursor composition and thermosetting resin. The resin-impregnated wood may have a coating containing the precursor composition or the thermosetting resin on its surface.

[0050] In the resin-component-containing crushed wood product preparation step according to the first manufacturing method, the method for crushing the resin-component-impregnated wood is not particularly limited as long as the contained precursor composition or thermosetting resin, etc. is not denatured, and conventionally known crushers, etc., can be used. Furthermore, the shape and size of the resulting resin-component-containing crushed wood are not particularly limited, and it is not necessarily required that the shape and size be uniform. However, from the viewpoints of workability in the first load preparation step and adhesion to the aluminum-containing roughened substrate and the decorative material, the major axis is preferably 0.05 to 10 mm, more preferably 0.1 to 5 mm.

[0051] The first loaded material preparation step in the first manufacturing method is a step of placing resin-component-containing crushed wood (precursor composition-containing crushed wood or uncured thermosetting resin-containing crushed wood) on the surface of the aluminum-containing roughened substrate having an overhang portion to prepare the first loaded material. The method and amount of resin-component-containing crushed wood are appropriately selected depending on the adhesion area of ​​the aluminum-containing roughened substrate and the decorative material, and are not particularly limited. Generally, it is preferable to place multiple resin-component-containing crushed wood pieces on the entire surface of a predetermined surface of the aluminum-containing roughened substrate without any gaps. However, as long as the first heat-pressing step suppresses void formation and a high-density intermediate layer consisting of a continuous phase is obtained, multiple resin-component-containing crushed wood pieces may be placed, for example, at equal intervals, so that a portion of the surface of the aluminum-containing roughened substrate is exposed.

[0052] The second load preparation step in the first manufacturing method is a step of placing a decorative material on the resin-containing crushed wood layer in the first load to prepare the second load. The decorative material can be a thin wood body, a thin wood body impregnated in whole or in part with a precursor composition or a thermosetting resin, a resin film, paper, a wooden board, etc. The thickness of the decorative material is not particularly limited.

[0053] The first heat-pressing step in the first manufacturing method is a step of heat-pressing a second load, which is formed by sequentially placing resin-containing wood crushed material and a decorative material on an aluminum-containing roughened substrate. The pressure direction is usually the loading direction. The press load and heating temperature are appropriately selected depending on the type of precursor composition or thermosetting resin contained in the resin-containing wood crushed material, and are not particularly limited. In the first heat-pressing step, the second load may be heated and pressed simultaneously, or the pressing of the second load may be delayed, with heating first and then pressing.

[0054] When using thermosetting resin-containing wood crushed material containing the above-mentioned urethane resin-forming composition as the resin component-containing wood crushed material, the blocked isocyanate compound is efficiently deblocked to produce an isocyanate compound, and this isocyanate compound reacts with polyethylene glycol to smoothly form polyurethane, so the heating temperature of the second load is preferably 80°C or higher, more preferably 100°C or higher.

[0055] The first hot pressing process makes it possible to efficiently produce a composite with excellent structural stability, consisting of an integrated product in which an aluminum-containing base and a decorative layer are joined via an intermediate layer made of a collection of resin-impregnated wood pieces.

[0056] Next, the second manufacturing method will be described. In the second manufacturing method, a resin-impregnated wood board is prepared (a resin-impregnated wood board preparation step), and then placed on the surface of the aluminum-containing roughened substrate obtained in the same aluminum-containing roughened substrate preparation step as in the first manufacturing method, with the overhanging portion, to prepare a third load (a third load preparation step). Next, a decorative material is placed on the resin-impregnated wood board in this third load to prepare a fourth load (a fourth load preparation step). Then, this fourth load is subjected to a hot press (a second hot press step). In the first manufacturing method, multiple resin-containing wood crushed pieces are placed between the aluminum-containing roughened substrate and the decorative material to produce the composite. In the second manufacturing method, at least one resin-impregnated wood board is placed between the aluminum-containing roughened substrate and the decorative material to produce the composite.

[0057] The resin-component-impregnated wood board manufacturing process in the second manufacturing method is a process for manufacturing a resin-component-impregnated wood board (a wood board containing a precursor composition or a wood board containing an uncured thermosetting resin) by impregnating a wood board with a resin component containing at least one selected from a precursor composition and a thermosetting resin. The wood board can be made of softwood or hardwood, and the resin-component-impregnated wood board can be resin-component-impregnated wood obtained by using a wood board as the wood in the first manufacturing method. The resin component can also be the same as the resin component in the first manufacturing method.

[0058] The method for producing a resin-impregnated wood board is not particularly limited, and may involve contacting a precursor composition or a thermosetting resin with a wood board having a thickness of preferably 0.01 to 20 mm, more preferably 0.05 to 5 mm. The contact conditions are appropriately set depending on the thickness of the wood board, the types of precursor composition and thermosetting resin, etc. The resin-impregnated wood board obtained by the resin-impregnated wood board production step may have a coating containing the precursor composition or the thermosetting resin on its surface.

[0059] The third loaded object preparation step in the second manufacturing method is a step of placing a resin-impregnated wood board (a wood board containing a precursor composition or a wood board containing an uncured thermosetting resin) on the surface of the aluminum-containing roughened substrate having an overhang portion to prepare a third loaded object. The external shape of the resin-impregnated wood board is usually approximately the same as that of the decorative material, and is approximately the same as the shape drawn by connecting the extreme ends of the overhang portions formed on the aluminum-containing roughened substrate. Note that the amount of resin-impregnated wood board placed (used amount) relative to the aluminum-containing roughened substrate is not particularly limited.

[0060] The fourth load fabrication step and the second hot-pressing step of the second manufacturing method can be directly applied to the second load fabrication step and the first hot-pressing step of the first manufacturing method, respectively. The second hot-pressing step makes it possible to efficiently manufacture a composite with excellent structural stability, which is an integrated product in which an aluminum-containing base and a decorative layer are joined via an intermediate layer made of a resin-impregnated wooden board.

[0061] The composite of the present invention is suitable for use as building materials and construction members, furniture and furnishings, vehicle members, home appliance parts, daily necessities, and the like.

[0062] When the third load in the second manufacturing method is subjected to a hot press in the loading direction, a bonded body of the resin-impregnated wood board and the aluminum-containing roughened base material can be obtained. If a good wood grain pattern or the like is observed on the surface of the resin-impregnated wood board on the side not bonded to the aluminum-containing roughened base material, this bonded body can also be suitably used for the above-mentioned composite applications.

[0063] The present invention will be explained in more detail below by way of examples, but the present invention is not limited to these examples.

[0064] 1. Preparation of Aluminum-Containing Roughened Substrate A flat plate (thickness: 1.6 mm) made of metal aluminum (material: A1050) or aluminum alloy (material: AC4CH, ADC12) was subjected to the following methods: Method 1 (acid treatment), Method 2 (electrical discharge machining), Method 3 (shot blasting), and Method 4 (sanding) to prepare a roughened metal aluminum substrate.

[0065] (Method 1) Acid treatment was performed by immersing a flat aluminum substrate in hydrochloric acid (pH 0.5) at 25°C for 10 minutes. (Method 2) Electrical discharge machining was performed on the surface of the aluminum substrate using a Fanuc wire electric discharge machine "α-C400iA" with tap water as the machining fluid and brass wire (φ0.3 mm) as the electrode. (Method 3) Shot blasting was performed on the surface of the aluminum substrate using a Daiei Dental Industry Co., Ltd. circulating sandblaster "Cycle Blaster Jr." by spraying glass beads with diameters of 600 to 850 μm onto the surface of the aluminum substrate at an air pressure of 0.40 MPa for 10 seconds. (Method 4) The surface of the aluminum substrate was sanded under dry conditions using SiC waterproof abrasive paper #120 (abrasive grain size 125 μm or less) until the metallic luster was lost.

[0066] Cross sections of each of the aluminum-containing roughened substrates obtained by methods 1, 2, 3, and 4 were photographed using a Keyence VHX-5000 digital microscope, including the outermost surface, and are shown in Figures 5 to 10. Figure 4 is a cross-sectional image of the metal aluminum plate before surface treatment, Figures 5, 6, and 7 are cross-sectional images of the metal aluminum plate, aluminum alloy plate (AC4CH), and aluminum alloy plate (ADC12), respectively, after acid treatment, Figure 8 is a cross-sectional image of the metal aluminum plate after electrical discharge machining, Figure 9 is a cross-sectional image of the aluminum alloy plate (ADC12) after shot blasting, and Figure 10 is a cross-sectional image of the metal aluminum plate after sanding. As is clear from Figures 5 to 10, methods 1, 2, and 3 resulted in the formation of overhanging portions on the surface of the metal aluminum substrate, while method 4 resulted in no overhanging portions on the surface of the metal aluminum substrate.

[0067] 2. Preparation of Thermosetting Resin-Containing Crushed Wood Materials After producing a thermosetting resin-impregnated wooden board, the thermosetting resin-impregnated wooden board was crushed while it was still uncured, and thermosetting resin-containing crushed wood materials were obtained by contacting the crushed wood materials with a thermosetting resin.

[0068] Preparation Example 1-1 (Preparation of Melamine Resin-Containing Wood Crushed Material) First, several plate-shaped samples (size: 80 mm (in the fiber direction) × approximately 80 mm (in the direction perpendicular to the fiber)) were prepared from cypress veneer (thickness: 1 mm) and dried with air at 105°C for at least 1 hour. Meanwhile, a melamine / formaldehyde resin "Amidia M-3 (60)" (trade name) manufactured by DIC Corporation was diluted with water to obtain a melamine / formaldehyde resin aqueous solution with a solids concentration of 50% by mass (hereinafter referred to as "melamine resin aqueous solution (1)"). Next, the dried plate-shaped samples were immersed in a container containing the melamine resin aqueous solution (1) at approximately 20°C. The solution was then subjected to a reduced pressure (0.01 MPa, 1 hour) at room temperature (approximately 20°C) and then pressurized (0.8 MPa, approximately 18 hours). The plate-shaped sample impregnated with the melamine resin aqueous solution (1) was then removed from the container, placed on a wire rack, and air-dried at room temperature (approximately 20°C) for two days. The sample was then dried at 35°C for approximately three days using a blower dryer, and then at 35°C for two or more days using a vacuum dryer, yielding a melamine resin-containing plate-shaped sample W1 (weight increase rate: 118% by mass) as a thermosetting resin-impregnated wood board. The melamine resin-containing plate-shaped sample W1 was then pulverized for approximately 30 seconds using a pulverizer "Wonder Crush / Mill WDL-1" (trade name) manufactured by Osaka Chemical Co., Ltd., to yield a melamine resin-containing crushed wood product C1 as a thermosetting resin-containing crushed wood product. The melamine resin-containing crushed wood C1 was then sieved and classified, and three types were collected: melamine resin-containing crushed wood C1-1 (150 μm pass) that passed through a 150 μm mesh, melamine resin-containing crushed wood C1-2 (150-300 μm) that passed through a 300 μm mesh but not through a 150 μm mesh, and melamine resin-containing crushed wood C1-3 (300 μm on) that did not pass through a 300 μm mesh. All of these melamine resin-containing crushed wood products contained residual wood cell fibers and had an elongated shape (average aspect ratio of 5 or more).

[0069] Preparation Example 1-2 (Preparation of Melamine Resin-Containing Crushed Wood) First, cypress veneer (3 mm thick) was crushed for approximately 30 seconds using the above-mentioned crusher to obtain crushed wood (shape: rod-shaped, size: diameter: approximately 500 mm or less). Next, the crushed wood was immersed in a container containing melamine resin aqueous solution (1) at approximately 20 ° C., and then reduced pressure (0.01 MPa, 1 hour) at room temperature (approximately 20 ° C.) and then pressurized (0.8 MPa, approximately 18 hours). The crushed wood impregnated with the melamine resin aqueous solution (1) was removed from the container, placed on a wire rack, and air-dried at room temperature (approximately 20 ° C.) for two days. Next, the crushed wood was dried using a blower dryer at 35 ° C. for approximately three days and then at 35 ° C. for two more days using a vacuum dryer to obtain melamine resin-containing crushed wood C2 (weight increase rate: 91% by mass) as thermosetting resin-impregnated wood.

[0070] 3. Preparation of Precursor Composition-Containing Crushed Wood Crushed wood containing a precursor composition was obtained by a method in which a precursor composition of a thermoplastic polyurethane resin was brought into contact with crushed wood.

[0071] Preparation Example 2-1 (Preparation of Wood Crushed Material Containing Polyurethane Precursor Composition) First, peeled Japanese cypress veneer (thickness: 3 mm) was crushed for about 30 seconds using the above-mentioned crusher to obtain wood crushed material (shape: rod-like, size: diameter: about 500 mm or less). Meanwhile, as a precursor composition for polyurethane resin, a blocked isocyanate compound, 2-[0-(1'-methylpropylideneamino)carboxyamino]ethyl methacrylate "KARENZ MOI-BM" (trade name) manufactured by Showa Denko K.K., and polyethylene glycol "PEG-1540" (trade name, molecular weight: 1540) manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., diluted with a solvent was used. This precursor composition was prepared by dissolving polyethylene glycol melted at 60°C in water to prepare an aqueous polyethylene glycol solution, cooling this aqueous polyethylene glycol solution to room temperature, mixing it with an ethanol solution obtained by dissolving a blocked isocyanate compound in ethanol, and adding water as necessary, resulting in a liquid composition with a polyethylene glycol:blocked isocyanate compound ratio of 1:1 (by mass) and a solids concentration of 50%, 30%, or 10% by mass. Next, three types of crushed wood products containing a precursor composition of a thermoplastic polyurethane resin were obtained by performing the same operation as in Preparation Example 1-2, except that the melamine resin aqueous solution (1) was replaced with each of the precursor compositions having a solids concentration of 50%, 30%, or 10% by mass. The precursor composition containing precursor composition C3 (weight increase rate: 81% by mass) was obtained using a precursor composition with a solid content of 50% by mass, the precursor composition containing precursor composition C4 (weight increase rate: 41% by mass) was obtained using a precursor composition with a solid content of 30% by mass, and the precursor composition containing precursor composition C5 (weight increase rate: 13% by mass) was obtained using a precursor composition with a solid content of 10% by mass.

[0072] 4. Preparation of Thermosetting Resin-Impregnated Wood Boards Thermosetting resin-impregnated wood boards were prepared by applying the melamine resin aqueous solution (1), which was a melamine / formaldehyde-based resin aqueous solution having a solids concentration of 50% by mass used in Preparation Example 1-1, the melamine resin aqueous solution (2), which was a melamine / formaldehyde-based resin aqueous solution having a lower solids concentration of 30% by mass, and the phenol / formaldehyde-based resin aqueous solution to cypress boards.

[0073] Preparation Example 3-1 First, several plate-shaped samples (size: approximately 100 mm (in the fiber direction) × approximately 200 mm (in the direction perpendicular to the fiber)) were prepared from cypress veneer (thickness: 3 mm) and dried with air at 105°C for at least one hour. Next, the dried plate-shaped samples were immersed in a container containing melamine resin aqueous solution (1) or (2) at approximately 20°C. In this state, the sample was subjected to reduced pressure (0.01 MPa, 1 hour) at room temperature (approximately 20°C), and then pressurized (0.8 MPa, approximately 18 hours). The plate-shaped samples impregnated with the melamine resin aqueous solution were then removed from the container, placed on a wire rack, and air-dried at room temperature (approximately 20°C) for two days. Next, the sample was dried in a blower oven at 35°C for approximately three days, and then in a vacuum oven at 35°C for at least two days. The boards were then cut to obtain thermosetting resin-impregnated wooden boards measuring 10 mm (in the fiber direction) × 10 mm (in the direction perpendicular to the fiber direction) × approximately 3 mm (thickness). The board obtained using melamine resin aqueous solution (1), which was a melamine / formaldehyde-based resin aqueous solution with a solids concentration of 50% by mass, was designated melamine resin-impregnated wooden board W2 (weight increase rate: 110% by mass), and the board obtained using melamine resin aqueous solution (2), which was a melamine / formaldehyde-based resin aqueous solution with a solids concentration of 30% by mass, was designated melamine resin-impregnated wooden board W3 (weight increase rate: 69% by mass).

[0074] Preparation Example 3-2 The same procedure as in Preparation Example 3-1 was carried out, except that an aqueous solution obtained by diluting a phenol / formaldehyde resin "AIKANEORESIN PX-341" (trade name) manufactured by AICA Kogyo Co., Ltd. with water (solid content concentration: 50% by mass, hereinafter referred to as "phenolic resin aqueous solution") was used instead of the melamine resin aqueous solution, to obtain a phenolic resin-impregnated wooden board W4 (weight increase rate: 127% by mass).

[0075] 5. Preparation of Precursor Composition-Impregnated Wood Board Using the precursor composition of the polyurethane resin used in Preparation Example 2-1, a precursor composition-impregnated wood board was obtained.

[0076] Preparation Example 4-1 The precursor composition of the polyurethane resin used in Preparation Example 2-1 was used and cut in the same manner as in Preparation Example 3-1 to obtain a precursor composition-impregnated wooden board W5 (weight increase rate: 64% by mass).

[0077] 6. Preparation of decorative materials The decorative materials used to manufacture the composites or laminates (for reference) are listed below.

[0078] Preparation Example 5-1 (Preparation of Wood Boards Containing Melamine Resin-Added Polyurethane Precursor) First, multiple plate-shaped samples (size: 200 mm (in the fiber direction) × approximately 300 mm (in the direction perpendicular to the fiber)) were prepared from Japanese cypress veneer (thickness: 4 mm) and dried with air at 105° C. for at least 1 hour. On the other hand, the precursor composition to be impregnated into the plate-shaped samples was a blocked isocyanate compound, 2-[0-(1′-methylpropylideneamino)carboxyamino]ethyl methacrylate "KARENZ MOI-BM" (trade name) manufactured by Showa Denko K.K., polyethylene glycol "PEG-1540" (trade name, molecular weight: 1540) manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., and a melamine / formaldehyde resin "Amidea M-3(60)" (trade name) manufactured by DIC Corporation, diluted with a solvent. This precursor composition was prepared by first dissolving polyethylene glycol melted at 60°C in water to prepare an aqueous polyethylene glycol solution, cooling the resulting polyethylene glycol solution to room temperature, adding a melamine / formaldehyde resin to form a mixed solution, and then mixing this mixed solution with an ethanol solution obtained by dissolving a blocked isocyanate compound in ethanol, with water added as needed. This preparation method yielded a melamine resin-added polyurethane precursor-containing liquid containing 35% ethanol by weight, with a polyethylene glycol 1540:blocked isocyanate compound:melamine / formaldehyde resin ratio of 1:1:1 (by weight), and a solids concentration of 20% by weight. Subsequently, a plate-shaped sample was impregnated with the melamine resin-added polyurethane precursor-containing liquid in the same manner as in Preparation Example 1-1, except that the melamine resin-added polyurethane precursor-containing liquid was used instead of the aqueous melamine resin solution, to obtain a melamine resin-added polyurethane precursor-containing wooden board (mass increase rate: 43% by weight, hereinafter referred to as "design material DD1").

[0079] Preparation Example 5-2: A cypress veneer (thickness 4 mm) was cut and processed to prepare a plate-shaped sample (size: 10 mm (in the direction of the fibers) x 10 mm (in the direction perpendicular to the fibers) with wood grain on the surface, which was used as a decorative material (hereinafter referred to as "decorative material DD2").

[0080] 7. Production and Evaluation of Composites Composites having a multilayer structure were produced using an aluminum-containing roughened substrate, resin-containing crushed wood or resin-impregnated wood board, and a decorative material.

[0081] Example 1: A metal aluminum plate (size: 20 mm x 20 mm) made of A1050 and having an overhang, obtained by acid treatment according to Method 1 above, was placed with its rough surface facing up on a hot plate preheated to 170°C and heated. Next, approximately 1 g of melamine resin-containing crushed wood material C1 was evenly distributed on the rough surface of the metal aluminum plate, and then decorative material DD1 was placed on top and hot pressed (170°C, 2 kN (5 MPa), 5 minutes). The plate was then cooled to approximately 40°C to obtain a composite.

[0082] An external image of the obtained composite (the design surface is the top) is shown in Figure 11. A cross-sectional image is also shown in Figure 12. These figures show that the resin precursor contained in the melamine resin-containing crushed wood material C1 is modified into a hardened resin by the heat press, forming an adhesive layer (intermediate layer) (4) with such a high density that no voids are formed, effectively bonding the acid-treated surface of the metal aluminum plate (2) and the decorative material DD1 (6). Furthermore, Figure 11 shows that the surface of the composite's decorative layer (6) retains its grain and provides a good wood texture.

[0083] Figure 13 is an enlarged image of the bonding interface between the intermediate layer (4) and the metal aluminum plate (2) of the resulting composite. From Figure 13, it can be seen that the unevenness of the surface of the metal aluminum plate, measured at the level of several tens of microns, was filled with the wood cells (cell walls) and hardened melamine resin contained in the melamine resin-containing crushed wood material C1. Furthermore, it was observed that the melamine resin oozed from the melamine resin-containing crushed wood material C1 into the interior of even smaller, minute overhangs, measured at the level of several microns, and then hardened to fill the gaps. The inventors believe that the hardened resin in the overhangs and the engagement of the wood cells result in a strong bond, thereby providing structural stability for the composite. The arrows (three in Figure 13) indicate cell walls derived from the Japanese cypress that make up the melamine resin-containing crushed wood material C1.

[0084] Example 2 A composite (not shown) was obtained in the same manner as in Example 1, except that a metal aluminum plate having an overhang made of A1050 and obtained by electrical discharge machining in the above-mentioned method 2 was used instead of the metal aluminum plate obtained by acid treatment in the above-mentioned method 1. When this composite was visually observed, its appearance was as good as that of the composite obtained in Example 1.

[0085] Comparative Example 1 The same operation as in Example 1 was carried out, except that a metal aluminum plate made of A1050 that had not been surface-treated was used instead of the metal aluminum plate obtained by acid treatment based on the above-mentioned Method 1. However, no integrated product was obtained after hot pressing.

[0086] Comparative Example 2 The same operation as in Example 1 was carried out, except that a metal aluminum plate made of A1050 with a sanded surface was used instead of the metal aluminum plate obtained by acid treatment based on the above-mentioned Method 1. However, no integrated product was obtained after hot pressing.

[0087] Example 3: A metal aluminum plate (size: approximately 10 mm x approximately 10 mm) made of A1050 and having an overhang, obtained by acid treatment according to Method 1 above, was placed with its rough surface facing up on a hot plate preheated to 170 ° C. and heated. Next, this metal aluminum plate was placed with its rough surface facing up in a mold (inner dimensions: 10 mm x 10 mm) preheated to 170 ° C., and the melamine resin-impregnated wood board W2 (size: 10 mm x 10 mm x approximately 3 mm) and decorative material DD2 were placed on top of it in this order, followed by a hot press (170 ° C, 0.5 kN (5 MPa), 5 minutes). The mixture was then cooled to approximately 40 ° C. to obtain a composite. An external image of the obtained composite (with the decorative surface facing up) is shown in Figure 14. It can be seen that the acid-treated surface of the metal aluminum plate and the decorative material DD2 are well bonded via an adhesive layer (intermediate layer) containing melamine cured resin. Furthermore, the surface of the decorative layer of the composite retained the cypress grain that was present in the decorative material DD2, and the high quality texture of the wood was maintained.

[0088] 8. Manufacturing and evaluation of laminates (1) The use of decorative materials was omitted, and an adhesive layer (intermediate layer) was formed on the surface of a metal aluminum substrate using crushed wood containing a resin component to form a laminate, and an experiment was conducted to confirm whether the two could be bonded properly.

[0089] Reference Example 1-1 An aluminum alloy plate (size: approximately 10 mm x approximately 10 mm) having an overhang made of AC4CH obtained by acid treatment based on the above method 1 was placed with its rough surface facing up on a hot plate preheated to 170 ° C. and heated. Next, this aluminum alloy plate was placed with its rough surface facing up in a mold (inner dimensions: 10 mm x 10 mm) preheated to 170 ° C., and approximately 1 g of the above melamine resin-containing crushed wood material C2 was evenly distributed on top and heated and pressed (170 ° C., 0.5 kN (5 MPa), 5 minutes). Then, it was cooled to approximately 40 ° C. to obtain a laminate. Visual observation of this laminate revealed that an aggregate of wood chips containing melamine cured resin formed a high-density layer and was well adhered to the rough surface of the aluminum alloy plate.

[0090] Reference Example 1-2 A laminate was obtained in the same manner as in Reference Example 1-1, except that an aluminum alloy plate having an overhang made of ADC12 was used instead of the aluminum alloy plate made of AC4CH. In this laminate, too, an aggregate of wood chips containing melamine cured resin formed a high-density layer and was well adhered to the rough surface of the aluminum alloy plate.

[0091] Reference Example 1-3 A laminate was obtained in the same manner as in Reference Example 1-1, except that an aluminum alloy plate having an overhang made of ADC12 was used instead of the aluminum alloy plate made of AC4CH, and precursor composition-containing crushed wood C3 was used instead of the melamine resin-containing crushed wood C2. Visual observation of this laminate revealed that an aggregate of wood chips containing polyurethane resin formed a high-density layer and was well adhered to the rough surface of the aluminum alloy plate.

[0092] Reference Example 1-4 A laminate was obtained in the same manner as in Reference Example 1-1, except that an aluminum alloy plate having an overhang made of ADC12 was used instead of the aluminum alloy plate made of AC4CH, and precursor composition-containing crushed wood material C4 was used instead of the melamine resin-containing crushed wood material C2. In this laminate, too, an aggregate of wood chips containing polyurethane resin formed a high-density layer and was well adhered to the rough surface of the aluminum alloy plate.

[0093] Reference Example 1-5 A laminate was obtained in the same manner as in Reference Example 1-1, except that an aluminum alloy plate having an overhang made of ADC12 was used instead of the aluminum alloy plate made of AC4CH, and precursor composition-containing crushed wood C5 was used instead of the melamine resin-containing crushed wood C2. In this laminate, too, an aggregate of wood chips containing polyurethane resin formed a high-density layer and was well adhered to the rough surface of the aluminum alloy plate.

[0094] 9. Manufacture and evaluation of laminate (2) The use of decorative materials was omitted, and a laminate was made by forming an adhesive layer (intermediate layer) on the surface of the metal aluminum base material using a resin-impregnated wooden board, and an experiment was conducted to confirm whether the two could be bonded properly.

[0095] Reference Example 2-1 A metal aluminum plate (size: approximately 10 mm x approximately 10 mm) having an overhang made of A1050 obtained by acid treatment based on the above method 1 was placed on a hot plate preheated to 170 ° C. with its rough surface facing up and heated. Next, this metal aluminum plate was placed in a mold (inner dimensions: 10 mm x 10 mm) preheated to 170 ° C. with its rough surface facing up, and the melamine resin-impregnated wood board W2 (size: 10 mm x 10 mm x approximately 3 mm) obtained in Preparation Example 3-1 was placed on top and heated (170 ° C., 0.5 kN (5 MPa), 5 minutes). Then, it was cooled to approximately 40 ° C. to obtain a laminate. When this laminate was visually observed, it was found that the thin plate containing the melamine cured resin was well adhered to the rough surface of the metal aluminum plate.

[0096] Reference Example 2-2 A laminate was obtained in the same manner as in Reference Example 2-1, except that an aluminum alloy plate having an overhang made of AC4CH was used instead of the metal aluminum plate made of A1050. In this laminate, too, the thin plate containing the melamine cured resin was well adhered to the rough surface of the aluminum alloy plate.

[0097] Reference Example 2-3 A laminate was obtained in the same manner as in Reference Example 2-1, except that an aluminum alloy plate having an overhang made of ADC12 was used instead of the metal aluminum plate made of A1050. In this laminate, too, the thin plate containing the melamine cured resin was well adhered to the rough surface of the aluminum alloy plate.

[0098] Reference Example 2-4: A laminate was obtained in the same manner as in Reference Example 2-1, except that the melamine resin-impregnated wood board W3 (size: 10 mm × 10 mm × approximately 3 mm) obtained in Preparation Example 3-1 was used instead of the melamine resin-impregnated wood board W2. In this laminate, the thin plate containing the melamine cured resin also adhered well to the rough surface of the metal aluminum plate.

[0099] Reference Example 2-5: A laminate was obtained in the same manner as in Reference Example 2-1, except that an aluminum alloy plate having an overhang made of AC4CH was used instead of the metal aluminum plate made of A1050, and the melamine resin-impregnated wood board W3 (size: 10 mm × 10 mm × approximately 3 mm) obtained in Preparation Example 3-1 was used instead of the melamine resin-impregnated wood board W2. In this laminate, too, the thin plate containing the melamine cured resin was well adhered to the rough surface of the aluminum alloy plate.

[0100] Reference Example 2-6: A laminate was obtained in the same manner as Reference Example 2-1, except that an aluminum alloy plate having an overhang made of ADC12 was used instead of the metal aluminum plate made of A1050, and the melamine resin-impregnated wood board W3 (size: 10 mm × 10 mm × approximately 3 mm) obtained in Preparation Example 3-1 was used instead of the melamine resin-impregnated wood board W2. In this laminate, the thin plate containing the melamine cured resin was well adhered to the rough surface of the aluminum alloy plate.

[0101] Reference Example 2-7: A laminate was obtained in the same manner as Reference Example 2-1, except that an aluminum alloy plate having an overhang made of AC4CH was used instead of the metal aluminum plate made of A1050, and the phenolic resin-impregnated wood board W4 (size: 10 mm × 10 mm × approximately 3 mm) obtained in Preparation Example 3-2 was used instead of the melamine resin-impregnated wood board W2. In this laminate, the thin plate containing the phenolic cured resin was well adhered to the rough surface of the aluminum alloy plate.

[0102] Reference Example 2-8: A laminate was obtained in the same manner as in Reference Example 2-1, except that an aluminum alloy plate having an overhang made of ADC12 was used instead of the metal aluminum plate made of A1050, and the precursor composition impregnated wood board W5 (size: 10 mm × 10 mm × approximately 3 mm) obtained in Preparation Example 4-1 was used instead of the melamine resin impregnated wood board W2. In this laminate, the thin plate containing polyurethane resin was well adhered to the rough surface of the aluminum alloy plate.

[0103] Reference Examples 3-1 to 3-3 Laminates were obtained in the same manner as in Reference Examples 2-1, 2-3, and 2-4, except that the treatment method for the metal aluminum plate was changed from Method 1 to Method 3, and designated as Reference Examples 3-1, 3-2, and 3-3, respectively. Visual observation of these laminates revealed that the thin plate containing the melamine cured resin and the metal aluminum plate were well bonded.

[0104] 10. Adhesion between the aluminum-containing roughened substrate and the hardened layer formed from the melamine resin-containing crushed wood C1 One side of a plate (30 mm x 25 mm x 1.6 mm) made of metal aluminum (A1050) or a plate (30 mm x 25 mm x 5.0 mm) made of aluminum alloy (A6063) was subjected to electrical discharge machining based on the above method 2 to produce two types of aluminum-containing roughened substrates. Then, this aluminum-containing roughened substrate, melamine resin-containing crushed wood C1-1, C1-2 or C1-3, and a melamine resin-containing plate-shaped sample W6 (hereinafter referred to as "thickness adjustment plate") prepared by the following method were used to produce a bonded test specimen bonded in this order, and a block shear test was performed to measure the compressive shear adhesive strength.

[0105] (Method for producing melamine resin-containing plate-shaped sample W6) A melamine resin-containing plate-shaped sample W6 was obtained by the same operation as in Production Example 1-1, except that a cypress board (size: 30 mm (fiber direction) × 25 mm (direction perpendicular to the fibers) × 4 mm (thickness)) and a melamine resin aqueous solution obtained by diluting the melamine resin aqueous solution (1) with water to a solid content concentration of 10 mass% were used.

[0106] Test Example 1 A roughened aluminum alloy substrate (A6063) was placed with its rough surface facing up on a hot plate preheated to 170°C and heated. Next, approximately 1.5 g of melamine resin-containing crushed wood C1-1 was evenly distributed over a portion (25 mm x 25 mm) of the roughened surface. Two thickness adjustment plates were then placed on top of each other and subjected to a hot press (170°C, 3.1 kN (5 MPa), 5 minutes). The test piece was then cooled to approximately 40°C to obtain a bonded test piece. Next, a block shear test was performed according to a method in accordance with JIS K 6852. Specifically, the bonded test piece was placed in a wood shear test fixture, and a load was applied to the wood material side with the aluminum substrate fixed at a test speed of 0.5 mm / min using a precision universal testing machine "AUTOGRAPH AG-X plus" (trade name) manufactured by Shimadzu Corporation. The bonded test piece was then subjected to a test to measure the bond area (625 mm ２ The maximum load (N) per bond area was measured and found to be 3.1 kN. The compressive shear bond strength (unit: MPa) was calculated using the following formula and found to be 7.8 MPa (see Table 1). Compressive shear bond strength = maximum load / bond area

[0107] Test Example 2 A bonded specimen was prepared in the same manner as in Test Example 1, except that melamine resin-containing crushed wood C1-2 was used instead of melamine resin-containing crushed wood C1-1. The maximum load and compressive shear bond strength were measured, and were found to be 3.1 kN and 8.6 MPa, respectively (see Table 1).

[0108] Test Example 3 A bonded specimen was prepared in the same manner as in Test Example 1, except that melamine resin-containing crushed wood C1-3 was used instead of melamine resin-containing crushed wood C1-1. The maximum load and compressive shear bond strength were measured, and were 3.1 kN and 9.6 MPa, respectively (see Table 1).

[0109] Test Example 4 A bonded specimen was prepared in the same manner as in Test Example 2, except that the press load during hot pressing was 1.0 kN (1.6 MPa). The maximum load and compressive shear bond strength were measured and found to be 1.0 kN and 8.1 MPa, respectively (see Table 1).

[0110] Test Example 5 A bonded specimen was prepared in the same manner as in Test Example 1, except that a roughened metal aluminum substrate (A1050) was used instead of the roughened aluminum alloy substrate (A6063). The maximum load and compressive shear bond strength were measured and found to be 3.1 kN and 9.4 MPa, respectively (see Table 1).

[0111] Test Example 6 A bonded specimen was prepared in the same manner as in Test Example 2, except that a roughened metal aluminum substrate (A1050) was used instead of the roughened aluminum alloy substrate (A6063). The maximum load and compressive shear bond strength were measured and found to be 3.1 kN and 8.0 MPa, respectively (see Table 1).

[0112] Test Example 7 A bonded specimen was prepared in the same manner as in Test Example 3, except that a roughened metal aluminum substrate (A1050) was used instead of the roughened aluminum alloy substrate (A6063). The maximum load and compressive shear bond strength were measured and found to be 3.1 kN and 9.9 MPa, respectively (see Table 1).

[0113] Test Example 8 A bonded specimen was prepared in the same manner as in Test Example 1, except that instead of the melamine resin-containing crushed wood material C1-1, a crushed composite material (hereinafter referred to as "crushed material P") was used, which was obtained by kneading equal weights of wood flour and polypropylene resin with an outer diameter of approximately 200 μm or less that was not impregnated with resin. The maximum load and compressive shear bond strength were measured and found to be 3.1 kN and 3.6 MPa, respectively (see Table 1).

[0114] Test Example 9 A bonded specimen was prepared in the same manner as in Test Example 4, except that crushed material P was used instead of melamine resin-containing crushed wood material C1-2. The maximum load and compressive shear bond strength were measured, and were found to be 1.0 kN and 4.6 MPa, respectively (see Table 1).

[0115] Test Example 10 A bonded specimen was prepared in the same manner as in Test Example 5, except that crushed wood P was used instead of melamine resin-containing crushed wood C1-1. The maximum load and compressive shear bond strength were measured, and were found to be 3.1 kN and 6.8 MPa, respectively (see Table 1).

[0116]

[0117] As is clear from Table 1, when melamine resin-containing crushed wood materials C1-1, C1-2, or C1-3 were used, the compressive shear bond strength to the aluminum substrate was greater and stronger bonding was achieved than when crushed wood material P was used. Furthermore, no difference was observed in the effect of the melamine resin-containing crushed wood material within the range of Test Examples 1 to 7, and it was confirmed that as long as the size was such that wood cell fibers were maintained, it contributed to strong bonding. Furthermore, even when the press load was reduced to about one-third (press pressure: 1.6 MPa), the compressive shear bond strength was at the same level as when the press pressure was 5 MPa.

[0118] The composite of the present invention is a multilayer structure having a base containing aluminum and excellent structural stability, and can be suitably used as a plate, a frame, etc., or as a building material / construction component, furniture / furnishings, vehicle component, home appliance component, daily necessities, etc., having an excellent appearance in the design layer.

[0119] 1: Composite 2: Base 4: Intermediate layer 6: Design layer 8: Overhang 9: Recessed portion 10: Aluminum-containing roughened substrate

Claims

1. A composite consisting of an integrated body in which an aluminum-containing base and a decorative layer are joined via an intermediate layer, the intermediate layer being made of an assembly of resin-impregnated wood pieces or a resin-impregnated wooden board, and the surface of the base on the intermediate layer side being provided with a plurality of overhanging portions.

2. The composite of claim 1, wherein said resin is also contained within the cell walls of said wood pieces or said wood boards.

3. The composite according to claim 1, wherein the resin is at least one selected from the group consisting of melamine resin, phenolic resin, urea resin, acrylic resin, styrene-based resin and urethane resin.

4. The composite according to claim 1, wherein the thickness of said intermediate layer is 0.1 to 20 mm.

5. The composite of claim 1, wherein said decorative layer comprises a thin body of wood.

6. The composite according to claim 1, wherein the overhang portion is formed by subjecting the surface of an article containing metallic aluminum or an aluminum alloy to an acid treatment, an electric discharge treatment, a shot blasting treatment or an electrolytic etching treatment.

7. A method for producing the composite described in claim 1, comprising the steps of: subjecting a base material containing metallic aluminum or an aluminum alloy to acid treatment, electric discharge machining treatment, shot blasting treatment or electrolytic etching treatment to form a plurality of overhanging portions on the surface of the base material to produce an aluminum-containing roughened base material; crushing resin-component-impregnated wood, in which wood is impregnated with a resin component containing at least one selected from a precursor of a thermoplastic resin and a thermosetting resin, to produce resin-component-containing crushed wood; placing the resin-component-containing crushed wood on the surface of the aluminum-containing roughened base material having the overhanging portions to produce a first load; placing a decorative material on the layer of resin-component-containing crushed wood in the first load to produce a second load; and subjecting the second load to hot pressing.

8. The method for producing a composite according to claim 7, wherein said thermoplastic resin is a urethane resin.

9. The method for producing a composite body according to claim 7, wherein said thermosetting resin contains at least one type selected from the group consisting of melamine resin, phenolic resin and urea resin.

10. The method for producing a composite material according to claim 7, wherein the major axis of the crushed wood material containing a resin component is 0.05 to 10 mm.

11. A method for producing the composite according to claim 1, comprising the steps of: subjecting a substrate containing metallic aluminum or an aluminum alloy to an acid treatment, an electric discharge machining treatment, a shot blasting treatment or an electrolytic etching treatment to form a plurality of overhanging portions on the surface of the substrate to produce an aluminum-containing roughened substrate; producing a resin component-impregnated wooden board by impregnating a wooden board with a resin component containing at least one selected from a precursor of a thermoplastic resin and a thermosetting resin; placing the resin component-impregnated wooden board on the surface of the aluminum-containing roughened substrate having the overhanging portions to produce a third load; placing a decorative material on the resin component-impregnated wooden board of the third load to produce a fourth load; and subjecting the fourth load to a hot press.

12. The method for producing a composite according to claim 11, wherein said thermoplastic resin is a urethane resin.

13. The method for producing a composite body according to claim 11, wherein the thermosetting resin contains at least one type selected from the group consisting of melamine resin, phenolic resin and urea resin.

14. The method for producing a composite body according to claim 11, wherein the thickness of said resin-impregnated wooden board is 0.01 to 20 mm.

15. A method for manufacturing a composite material as claimed in claim 7 or 11, wherein the decorative material comprises a thin-walled body of wood.

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