Metal-resin composite material, vehicle using same, and method for dismantling metal-resin composite material

Abstract

To provide a metal resin composite material which is strongly bonded, can be easily disassembled and is composed of a fiber-reinforced resin and a metal member.SOLUTION: A metal resin composite material is a metal resin composite material 10 in which a metal member 2 and a fiber-reinforced resin 1 are bonded to each other through an adhesive 3, wherein the fiber-reinforced resin 1 is composed of a resin having a kinetic covalent bond reversibly dissociable and bondable to the adhesive 3, and a fiber, the adhesive 3 is a thermosetting adhesive which is any one of an epoxy resin, an urethane resin and an acrylic resin, and a glass transition temperature of the adhesive 3 is lower than a glass transition temperature of the fiber-reinforced resin 1. The metal resin composite material 10 is heated to a temperature equal to or higher than the glass transition temperature of the adhesive 3 and equal to or lower than the glass transition temperature of the fiber-reinforced resin 1 and peeled, and thereby can be easily disassembled.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a metal-resin composite material, a vehicle using the same, and a method for dismantling a metal-resin composite material. [Background technology]

[0002] In response to environmental regulations and energy conservation, efforts are being made to reduce the weight of moving bodies such as automobiles, aircraft, and railway vehicles. In particular, weight reduction and increased rigidity have been achieved by constructing structural members by attaching fiber-reinforced resin containing fibers to metal members. Patent Document 1 describes attaching carbon fiber-reinforced resin to the double skin material of a railway vehicle body structure to increase the rigidity of the body structure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-86588 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology described in Patent Document 1 bonds metal and fiber-reinforced resin with an adhesive, and in some cases, rivets, Huck bolts, etc. are also used. These metal-resin composites, made of metal and resin, require that the components be firmly bonded or joined together during use. However, in the event of a defective product during manufacturing or after use, it is desirable that the components be easily separated so that the metal, resin, and other constituent components can be recycled. Due to stricter environmental regulations, recyclability is also strongly required, and it is difficult to achieve both of these contradictory properties: adhesion and easy disassembly. With the technology described in Patent Document 1, the use of an adhesive makes it difficult for the metal and fiber-reinforced resin to separate, making it difficult to recycle the fiber-resin components.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a metal-resin composite material in which a metal member and a fiber-reinforced resin are bonded with an adhesive, which can be easily disassembled. [Means for solving the problem]

[0006] One example of the "metal-resin composite" of the present invention for solving the above-mentioned problems is a metal-resin composite in which a metal member and a fiber-reinforced resin are bonded via an adhesive, wherein the fiber-reinforced resin is composed of a resin and fibers having a dynamic covalent bond that can reversibly dissociate and bond with the adhesive, and the glass transition temperature of the adhesive is lower than the glass transition temperature of the fiber-reinforced resin.

[0007] Furthermore, one example of the "method for dismantling a metal-resin composite" of the present invention is a method for dismantling a metal-resin composite in which a metal member and a fiber-reinforced resin are bonded via an adhesive, characterized in that the bonded portion between the fiber-reinforced resin and the metal member is heated to a temperature equal to or higher than the glass transition temperature of the adhesive and equal to or lower than the glass transition temperature of the fiber-reinforced resin, thereby releasing the bond and separating the metal member from the fiber-reinforced resin, thereby dismantling the metal-resin composite. [Effects of the Invention]

[0008] According to the present invention, the chemical bond between the adhesive and the fiber-reinforced resin is dissociated due to the reversibility of the bond when the metal-resin composite material is heated, making it possible to easily separate the metal member and the fiber-reinforced resin.

[0009] Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional schematic view of a metal-resin composite material of the present invention. [Figure 2] FIG. 1 is a diagram showing the interaction between the functional groups of the fiber-reinforced resin and the functional groups of the adhesive layer in the metal-resin composite material of the present invention, and is a diagram showing the state in which the fiber-reinforced resin and the adhesive layer are chemically bonded. [Figure 3] 1A to 1C are diagrams illustrating a method for dismantling a metal-resin composite material according to the present invention. [Figure 4]1 is a schematic diagram of an automobile using a metal-resin composite material of the present invention. [Figure 5] 1 is a schematic diagram of a railway vehicle using the metal-resin composite material of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the metal-resin composite material and the method for dismantling the metal-resin composite material of the present invention will be described in detail with reference to the drawings as appropriate. However, the present invention should not be interpreted as being limited to the description of the embodiments shown below. Those skilled in the art will easily understand that the specific configuration can be changed within the scope of the idea or gist of the present invention.

[0012] 1 is a cross-sectional view of a metal resin composite 10. The metal resin composite 10 is constructed by bonding a fiber reinforced resin 1 having a covalent bond (hereinafter referred to as a dynamic covalent bond) that reversibly dissociates and bonds with an adhesive to a metal member 2 via an adhesive layer 3. A dynamic covalent bond is formed between the fiber reinforced resin 1 and the adhesive layer 3 between functional groups present on the surface of the fiber reinforced resin 1 and functional groups present on the surface of the adhesive layer 3.

[0013] The dynamic covalent bond is, for example, an ester bond, and the target functional group is, for example, a hydroxyl group, but is not limited to these. The dynamic covalent bond will be explained with reference to Chemical Formula 1. Chemical Formula 1 is the structure of the dynamic covalent bond of the present invention. Note that Chemical Formula 1 is a part of the structure obtained by transesterification. Note that in this chemical reaction formula, R, R', and R'' represent any chemical structure. For example, the fiber-reinforced resin 1 and the adhesive layer 3 are chemically bonded by forming a dynamic covalent bond through bonding between functional groups present on the surface. In Chemical Formula 1, the left side indicates the bonding state.

[0014] [ka]

[0015] On the other hand, in the state of the left side, by heating at least the bonded portion and applying stress, the dynamic covalent bond is rearranged and the reaction proceeds to the right side. As a result, the dynamic covalent bond formed by the R'O of the fiber-reinforced resin 1 and the R''OH of the adhesive layer 3 is dissociated, resulting in the fiber-reinforced resin 1 shown in the first item on the right side and the adhesive layer 3 shown in the second item on the right side. As a result, the ester bond formed between the fiber-reinforced resin 1 and the adhesive layer 3 is easily broken, causing the dynamic covalent bond to rearrange and the bond to be released.

[0016] The resin of the fiber-reinforced resin of the present invention is not particularly limited as long as it is a resin that forms a dynamic covalent bond with the adhesive, and examples thereof include at least one of epoxy resin, phenolic resin, polyester resin, etc. Among these, epoxy resin is preferable. Epoxy resin has the advantage that by adjusting the composition ratio of the epoxy compound and the acid anhydride curing agent, dynamic covalent bonds can be easily introduced through the curing reaction, forming an ester group and a hydroxyl group. Below, an example will be given in which the resin of the fiber-reinforced resin is an epoxy resin, but the first resin is not limited to an epoxy resin.

[0017] The epoxy resin can be obtained by curing a mixture containing, for example, an epoxy compound having two or more epoxy groups in the molecule, at least one curing agent selected from carboxylic acids or carboxylic anhydrides, and a transesterification catalyst that promotes the transesterification reaction. The mixture may further contain a polymerization initiation catalyst, etc.

[0018] Examples of epoxy compounds having two or more epoxy groups in the molecule include bisphenol A resins, novolac resins, alicyclic resins, and glycidylamine resins. Examples of epoxy compounds include bisphenol A diglycidyl ether phenol, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, resorcinol diglycidyl ether, hexahydrobisphenol A diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, phthalic acid diglycidyl ester, dimer acid diglycidyl ester, triglycidyl isocyanurate, tetraglycidyldiaminodiphenylmethane, tetraglycidylmeta-xylenediamine, cresol novolac polyglycidyl ether, tetrabromobisphenol A diglycidyl ether, and bisphenol hexafluoroacetone diglycidyl ether, but are not limited thereto.

[0019] Examples of carboxylic acids and acid anhydrides that serve as curing agents include, but are not limited to, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, 3-dodecenylsuccinic anhydride, octenylsuccinic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, dodecylsuccinic anhydride, chlorendic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, ethylene glycol bis(anhydrotrimate), methylcyclohexenetetracarboxylic anhydride, trimellitic anhydride, polyazelaic anhydride, ethylene glycol bisanhydrotrimellitate, 1,2,3,4-butanetetracarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, and polyvalent fatty acids.

[0020] The amount of acid anhydride added is, for example, 30 mol% or more and 70 mol% or less relative to the epoxy groups. It is more desirable to use 40 mol% or more and 60 mol% or less. By using an amount of acid anhydride within this range, hydroxyl groups remain after polymerization, allowing for efficient reorganization of the polymer structure through dynamic covalent bonds. In particular, using an amount of acid anhydride of 30 mol% or more allows for sufficient curing. Using an amount of acid anhydride of 70 mol% or less increases the amount of hydroxyl groups produced, facilitating the progress of the transesterification reaction.

[0021] The resin of the fiber reinforced resin may contain a vinyl monomer having a hydroxyl group, an ester group, and two or more vinyl groups, and a polymerization initiator catalyst for polymerizing the vinyl monomer. Specific examples of the vinyl monomer include 2-hydroxymethacrylate, hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, divinylethylene glycol, monomethyl fumarate, hydroxypropyl acrylate, ethyl 2-(hydroxymethyl)acrylate, glycerol dimethacrylate, allyl acrylate, methyl crotonate, methyl methacrylate, methyl 3,3-dimethacrylate, diethylene glycol dimethacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, dimethyl fumarate, and fumarate. Examples of suitable methacrylates include, but are not limited to, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,3-butanediol dimethacrylate, tetraethylene glycol dimethacrylate, tetraethylene glycol diacrylate, vinyl crotonate, crotonic anhydride, diallyl maleate, neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, bisphenol A glycerolate dimethacrylate, and the like.

[0022] Examples of the polymerization initiator catalyst include peroxide polymerization initiators and azo compound polymerization initiators. Specific examples include azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile), 1,1'-azobis(cyclohexanecarbonitrile), and 2,2'-azobis(2,4,4-trimethylpentane); dialkyl peroxides such as di-t-butyl peroxide, di-t-hexyl peroxide, and dicumyl peroxide; 1,1-bis(t-butylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, and 2,2-bis(4,4-di-t-butylperoxy)cyclohexane; peroxyketals such as t-butylperoxycyclohexylpropane; peroxyesters such as t-butylperoxybenzoate, t-hexylperoxybenzoate, t-butylperoxyacetate, t-butylperoxylaurate, and t-hexylperoxyneodecanoate; diacyl peroxides such as benzoyl peroxide and lauroyl peroxide; and peroxycarbonates such as t-butylperoxyisopropyl monocarbonate, t-hexylperoxyisopropyl monocarbonate, di-n-propylperoxydicarbonate, diisopropylperoxydicarbonate, and di-2-ethylhexylperoxydicarbonate, but are not limited to these.

[0023] The transesterification catalyst is preferably one that disperses uniformly in the mixture and promotes the transesterification reaction. For example, manganese(III) acetylacetonate, manganese(III) naphthanate, manganese(III) isopropoxide, manganese(III) acetate, manganese(III) di(2-ethylhexanoate), zinc(II) acetate, zinc(II) acetylacetonate, zinc(II) naphthenate, iron(III) acetylacetonate, cobalt(II) acetylacetonate, cobalt(III) acetylacetonate, aluminum isopropoxide, titanium isopropoxide, methoxide(triphenylphosphine) copper(I) complex, ethoxide(triphenylphosphine) copper(I) complex, propoxide(triphenylphosphine) copper(I) complex, isopropoxide(triphenylphosphine) copper(I) complex, methoxidebis(triphenylphosphine) copper(II). complex, ethoxidebis(triphenylphosphine)copper(II) complex, propoxidebis(triphenylphosphine)copper(II) complex, isopropoxidebis(triphenylphosphine)copper(II) complex, tris(2,4-pentanedionato)cobalt(III), cobalt naphthenate(II), cobalt stearate(II), tin diacetate(II), tin di(2-ethylhexanoate)(II), N,N-dimethyl-4-aminopyridine, diazabicycloundecene, diazabicyclononene, triazabicyclodecene, triphenylphosphine, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-phenylimidazole, and the like.

[0024] The fiber reinforced resin 1 of the present invention contains fibers. By containing fibers, the strength and rigidity of the fiber reinforced resin can be improved.

[0025] Fibers include inorganic and organic fibers. Examples of inorganic fibers include aramid fibers, glass fibers, asbestos fibers, carbon fibers, silica fibers, silica-alumina fibers, alumina fibers, zirconia fibers, potassium titanate fibers, Tyranno fibers, silicon carbide fibers, and metal fibers. Examples of organic fibers include high-strength polyethylene fibers, polyacetal fibers, aliphatic or aromatic polyamide fibers, polyacrylate fibers, fluorine fibers, boron fibers, polyacrylonitrile fibers, aramid fibers, and PBO (poly-p-phenylene benzobisoxazole) fibers. These fibers can be used alone or in combination. Among these fibers, organic fibers, particularly carbon fibers, are preferred in terms of mechanical strength. Carbon fibers can be classified based on their raw materials into synthetic polymer-derived carbon fibers (e.g., polyacrylonitrile-based, polyvinyl alcohol-based, and rayon-based carbon fibers) and mineral-derived carbon fibers (e.g., pitch-based carbon fibers). Among these, synthetic polymer-derived carbon fibers are preferred in terms of mechanical strength. These fibers are used in the form of continuous fibers, long fibers, short fibers, chopped fibers, etc., and in the form of unidirectional materials, plain weaves, nonwoven fabrics, etc. They may also be added directly to resins, but the present embodiment is not limited to these fiber shapes and fiber states. Methods for producing fiber-reinforced resins containing fibers include a method in which resin-impregnated fibers are stacked and pressurized and heated, a method in which resin is injected into a mold with fibers laid therein and heated, and a method in which fibers are mixed into resin and injection molded.

[0026] Furthermore, the fiber-reinforced resin 1 may contain an inorganic filler. Examples of inorganic fillers that can be used in the present invention include powders such as fused silica, crystalline silica, alumina, zircon, calcium silicate, calcium carbonate, potassium titanate, silicon carbide, aluminum nitride, boron nitride, beryllia, zircon, fosterite, stearite, spirel, mullite, and titania, as well as spherical beads and glass fibers made from these. There are no limitations on the shape of the inorganic filler, and any shape, such as spherical or flaky, may be used.

[0027] Furthermore, the fiber reinforced resin 1 may contain additives such as a curing accelerator, a flame retardant, an antioxidant, a light stabilizer, a dispersant, a lubricant, a plasticizer, an antistatic agent, a pigment, and a dye, as needed.

[0028] The metal member 2 of the present invention is a member to be reinforced with fiber-reinforced resin. Examples of the metal member 2 include steel, aluminum, aluminum alloy, magnesium alloy, and titanium alloy.

[0029] The adhesives used in the present invention include urethane, epoxy, and acrylic resins. These adhesives have, for example, hydroxyl groups or ester groups as target functional groups for dynamic covalent bonding. For the disassembly method described below, the glass transition temperature of the cured adhesive layer must be lower than the glass transition temperature of the fiber-reinforced resin.

[0030] Urethane resins used as adhesives are obtained by polymerizing polyols and polyisocyanates. An adhesive layer can be obtained by mixing the polyols and polyisocyanates in a predetermined ratio, applying the mixture, and then curing the mixture. The polyols are not particularly limited. Specific examples include polyester polyols, polyether polyols, acrylic polyols, and low-molecular-weight polyols. These can be used alone or in combination of two or more. The polyisocyanates are not particularly limited. Examples include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylene-1,4-diisocyanate, xylene-1,3-diisocyanate, 4,4'-diphenylmethane diisocyanate, and modified mixtures thereof. These can be used alone or in combination of two or more.

[0031] Epoxy resin adhesives are obtained by reacting an epoxy compound containing two or more epoxy groups in its molecule with an amine, an acid anhydride, or a carboxylic acid.

[0032] The acrylic resin used as an adhesive is obtained by reacting an acrylic monomer with a curing agent.

[0033] FIG. 2 is a diagram illustrating the interaction between functional groups of fiber-reinforced resin 1 and adhesive layer 3 in a metal-resin composite of the present invention, showing a state in which a metal member 2 and fiber-reinforced resin 1 are bonded via adhesive layer 3. As shown in FIG. 2, metal-resin composite 10 includes fiber-reinforced resin 1 and adhesive layer 3. Fiber-reinforced resin 1 is composed of a resin and fibers that form dynamic covalent bonds with the adhesive. In metal-resin composite 10, a reversible, dissociable transesterification reaction occurs at the interface between fiber-reinforced resin 1 and adhesive layer 3. Specifically, an ester bond is formed between an ester group or hydroxyl group constituting fiber-reinforced resin 1 and a hydroxyl group or ester group in adhesive layer 3, chemically bonding fiber-reinforced resin 1 and adhesive layer 3. This ester bond is the dynamic covalent bond described above, and is reversibly cleaved.

[0034] FIG. 3 shows a method for dismantling the metal-resin composite material 10. When the metal-resin composite material 10 has been used and is to be discarded, the method shown in FIG. 3 can be applied to separate and discard the fiber-reinforced resin 1 and the metal member 2. By heating the joint portion of the metal-resin composite material 10 and applying a peeling stress, the ester bond formed between the fiber-reinforced resin 1 and the adhesive 3 is broken. As a result, the adhesive strength is reduced, and the fiber-reinforced resin 1 can be easily peeled from the adhesive layer 3. As a result, the metal-resin composite material 10 can be easily dismantled and recycled.

[0035] These heating methods can be used. For example, the entire product may be heated in a thermostatic bath or the like, or a desired position may be partially heated by irradiating the desired position with microwaves or infrared rays. Furthermore, the product may be heated by pressing a metal plate heated by an electric heater or the like against the desired position.

[0036] When separating, heating may be performed while applying a pulling force in the lamination direction of the fiber reinforced resin 1 and the metal member 2, or heating may be performed without applying such a force. Furthermore, when heating is performed without applying such a force, they can also be separated by applying a pulling force after heating.

[0037] The heating temperature varies depending on the material composition and compounding ratio of the fiber reinforced resin 1 and the adhesive layer 3, but is, for example, approximately 100°C to 150°C. This temperature is below the glass transition temperature of the resin contained in the fiber reinforced resin 1 and above the glass transition temperature of the adhesive layer 3. By heating within this temperature range, the adhesive layer 3 becomes rubbery due to heating, and the elastic modulus decreases, making it easier to peel. Furthermore, by becoming rubbery, the transesterification reaction progresses more easily, and ester bonds are broken at the interface between the fiber reinforced resin 1 and the adhesive layer 3, making it easier to peel.

[0038] If the heating temperature is below the glass transition temperature of the adhesive layer 3, the transesterification reaction does not proceed easily and the elastic modulus of the adhesive layer 3 is maintained, resulting in high adhesive strength and difficulty in peeling. If the heating temperature is above the glass transition temperature of the fiber-reinforced resin 1, the fiber-reinforced resin 1 as well as the adhesive layer 3 will become rubbery, making peeling easier, but the matrix of the fiber-reinforced resin 1 will be destroyed, making this unsuitable for recycling.

[0039] Next, the present invention will be described in more detail with reference to examples. To dismantle the metal-resin composite, the composite was placed in a thermostatic chamber and heated at a given temperature for 10 minutes. Immediately after 10 minutes of heating, the fiber-reinforced resin and metal components were peeled off by hand to evaluate dismantling properties. Materials that had no adhesive attached to the fiber-reinforced resin and could be peeled off without breaking were deemed to be easily dismantlable.

[0040] This will be explained in detail below.

[0041] [Example 1] A fiber-reinforced resin was prepared as follows. First, 100 parts by mass of a bisphenol A diglycidyl ether epoxy compound (jER828, manufactured by Mitsubishi Chemical Corporation) was mixed with 44 parts by mass of an acid anhydride (HN-2200, manufactured by Showa Denko Materials Co., Ltd.), 19 parts by mass of manganese(III) acetylacetonate (a transesterification catalyst, manufactured by Tokyo Chemical Industry Co., Ltd.), and 0.3 parts by mass of 2E4MZ-CN (manufactured by Shikoku Chemical Industry Co., Ltd.) as a curing accelerator, and the mixture was stirred and mixed in the air to obtain a mixture. The amount of acid anhydride used was 50 mol% (half the amount in stoichiometric ratio) relative to the amount of epoxy compound used, and the amount of manganese(III) acetylacetonate used was 10 mol% relative to the amount of epoxy compound used. Next, the mixture was impregnated into carbon fiber (CO6343B, manufactured by Toray Industries, Inc.) using a vacuum infusion method, and then heated at 100°C for 1 hour and then at 200°C for 1 hour to cure the mixture, yielding a flat-plate-shaped fiber-reinforced resin. The glass transition temperature of this fiber-reinforced resin is 150°C. The fiber-reinforced resin has ester bonds formed by dehydration condensation between acid anhydrides and hydroxyl groups as dynamic covalent bonds on its surface and inside. The fiber-reinforced resin was then bonded to an aluminum alloy plate, which is a metal component, using a urethane adhesive to obtain a metal-resin composite. The glass transition temperature of the urethane adhesive is 80°C. The metal-resin composite was placed in a thermostatic chamber and heated at 100°C for 10 minutes. Immediately after 10 minutes of heating, the fiber-reinforced resin and the metal component were manually peeled off to evaluate disassembly. It was confirmed that the adhesive did not adhere to the fiber-reinforced resin and that the fiber-reinforced resin could be peeled off without breaking.

[0042] [Example 2] The fiber-reinforced resin described in Example 1 and an aluminum alloy metal member were bonded with an epoxy adhesive to obtain a metal-resin composite. The glass transition temperature of the epoxy adhesive was 100°C. The produced metal-resin composite was placed in a thermostatic chamber and heated at 120°C for 10 minutes. Immediately after 10 minutes of heating, the fiber-reinforced resin and the metal member were peeled off by hand, and dismantling was evaluated. As a result, it was confirmed that the adhesive did not adhere to the fiber-reinforced resin, and the fiber-reinforced resin could be peeled off without breaking.

[0043] [Example 3] The fiber-reinforced resin described in Example 1 and an aluminum alloy metal member were bonded with an acrylic adhesive to obtain a metal-resin composite. The glass transition temperature of the acrylic adhesive was 110°C. The produced metal-resin composite was placed in a thermostatic chamber and heated at 130°C for 10 minutes. Immediately after 10 minutes of heating, the fiber-reinforced resin and the metal member were peeled off by hand to evaluate dismantling properties. As a result, it was confirmed that the adhesive did not adhere to the fiber-reinforced resin and that the fiber-reinforced resin could be peeled off without breaking.

[0044] [Comparative Example 1] A fiber-reinforced resin was prepared in the same manner as in Example 1, except that the amount of acid anhydride used was 100 mol% (stoichiometrically equivalent) relative to the amount of epoxy compound used. In Comparative Example 1, the epoxy compound and acid anhydride reacted stoichiometrically during preparation, and the fiber-reinforced resin did not have a dynamic covalent bond. This fiber-reinforced resin was bonded to an aluminum alloy plate, which was a metal member, with a urethane adhesive to obtain a metal-resin composite. The glass transition temperature of the urethane adhesive was 80°C. The prepared metal-resin composite was placed in a thermostatic chamber and heated at 100°C for 10 minutes. Immediately after 10 minutes of heating, the fiber-reinforced resin and the metal member were manually peeled off, and disassembly was evaluated. Cohesive failure of the adhesive occurred, and the adhesive adhered to the fiber-reinforced resin after peeling. This is because the adhesive and resin were not dynamically covalently bonded, so no bond recombination occurred at the interface, making them difficult to peel off.

[0045] Comparative Example 2 The metal-resin composite material described in Example 1 was placed in a thermostatic chamber and heated at 50°C for 10 minutes. Immediately after 10 minutes of heating, the fiber-reinforced resin and the metal member were peeled off by hand, and dismantling was evaluated. As a result, cohesive failure of the adhesive occurred, and the adhesive adhered to the fiber-reinforced resin after peeling.

[0046] Comparative Example 3 The metal-resin composite material described in Example 1 was placed in a thermostatic chamber and heated at 180°C for 10 minutes. Immediately after 10 minutes of heating, the fiber-reinforced resin and the metal member were peeled off by hand, and dismantling was evaluated. As a result, the fiber-reinforced resin matrix was destroyed, and the fiber-reinforced resin itself was destroyed.

[0047] Comparative Example 4 The metal-resin composite material described in Example 2 was placed in a thermostatic chamber and heated at 50°C for 10 minutes. Immediately after 10 minutes of heating, the fiber-reinforced resin and the metal member were peeled off by hand, and dismantling was evaluated. Cohesive failure of the adhesive occurred, and the adhesive adhered to the fiber-reinforced resin after peeling.

[0048] Comparative Example 5 The metal-resin composite material described in Example 2 was placed in a thermostatic chamber and heated at 180°C for 10 minutes. Immediately after 10 minutes of heating, the fiber-reinforced resin and the metal member were peeled off by hand, and dismantling was evaluated. As a result, the fiber-reinforced resin matrix was destroyed, and the fiber-reinforced resin itself was destroyed.

[0049] Comparative Example 6 The metal-resin composite material described in Example 3 was placed in a thermostatic chamber and heated at 50°C for 10 minutes. Immediately after 10 minutes of heating, the fiber-reinforced resin and the metal member were peeled off by hand, and dismantling was evaluated. Cohesive failure of the adhesive occurred, and the adhesive adhered to the fiber-reinforced resin after peeling.

[0050] Comparative Example 7 The metal-resin composite material described in Example 3 was placed in a thermostatic chamber and heated at 180°C for 10 minutes. Immediately after 10 minutes of heating, the fiber-reinforced resin and the metal member were peeled off by hand, and dismantling was evaluated. As a result, the fiber-reinforced resin matrix was destroyed, and the fiber-reinforced resin itself was destroyed.

[0051] From the above results, the metal resin composites produced in Examples 1 to 3 can be easily disassembled by heating them to a temperature below the glass transition temperature of the fiber reinforced resin and above the glass transition temperature of the adhesive and peeling them off.

[0052] [Example 4] An example of an automobile using the metal resin composite material of the present invention in the body is shown in Figure 4. The metal resin composite material of the present invention is used in the automobile body 20. The metal member of the metal resin composite material is preferably a body steel plate. [Example 5] An example of a railway vehicle using the metal resin composite material of the present invention in its body is shown in Figure 5. The metal resin composite material of the present invention is used in the railway vehicle body 30. The metal member of the metal resin composite material is preferably an aluminum alloy plate.

[0053] In vehicles such as automobiles and railcars that use the metal-resin composite material of the present invention in their car bodies, the use of the metal-resin composite material can reduce the weight of the car body and improve the rigidity of the car body, and the metal members and resin can be easily disassembled during recycling.

[0054] The metal-resin composite material of the present invention can be used for vehicle parts as well as parts and bodies used in various fields, such as ships, aircraft, modular baths, septic tanks, printed circuit boards, playground equipment, skis, etc. The size and shape can vary depending on the desired size and shape of the above-mentioned parts, etc.

[0055] According to the present invention, when dismantling a metal-resin composite, the composite is heated to a temperature above the glass transition temperature of the adhesive and below the glass transition temperature of the fiber-reinforced resin. This dissociates the chemical bond between the adhesive and the fiber-reinforced resin due to the reversibility of the bond, allowing for easy separation at the interface between the adhesive layer and the fiber-reinforced resin. This allows the fiber-reinforced resin to be peeled from the metal member without the adhesive adhering to the fiber-reinforced resin or destroying the fiber-reinforced resin. This allows for easy recycling of the metal member and the resin components. [Explanation of symbols]

[0056] 1 Fiber reinforced resin 2 Metallic parts 3 Adhesive layer (adhesive) 10 Metal resin composite material 20 Automobile body 30 Railway vehicle body

Claims

1. A metal-resin composite material in which a metal member and a fiber-reinforced resin are bonded via an adhesive, The fiber-reinforced resin is composed of a resin and a fiber having a dynamic covalent bond that can be reversibly dissociated and bonded to an adhesive, the adhesive has a glass transition temperature lower than the glass transition temperature of the fiber-reinforced resin; The fiber-reinforced resin is filled with an epoxy resin in which an ester bond and a hydroxyl group are formed through a curing process, The metal-resin composite material is characterized in that the fiber-reinforced resin contains any one of manganese (III) acetylacetonate, manganese (III) acetate, and manganese (III) naphthanate as an ester exchange reaction catalyst.

2. The metal-resin composite material according to claim 1, A metal-resin composite material characterized in that a dynamic covalent bond is formed between a functional group present on the surface of the fiber-reinforced resin and a functional group present on the surface of the adhesive layer.

3. The metal-resin composite material according to claim 1, The metal-resin composite material is characterized in that the metal member is a member made of steel, aluminum, or an aluminum alloy.

4. The metal-resin composite material according to claim 1, The metal resin composite material is characterized in that the fiber reinforced resin is composed of one of epoxy resin, phenolic resin, and polyester resin and the fibers.

5. The metal-resin composite material according to claim 1, A metal-resin composite material characterized in that the fiber-reinforced resin contains any one of aramid fiber, glass fiber, and carbon fiber.

6. The metal-resin composite material according to claim 1, The metal-resin composite material is characterized in that the adhesive is a thermosetting adhesive selected from the group consisting of epoxy, urethane, and acrylic.

7. A vehicle using the metal-resin composite material according to claim 1 in a body.

8. A vehicle as claimed in claim 7, The vehicle is a motor vehicle, The vehicle, wherein the metal member is a body steel plate.

9. A vehicle as claimed in claim 8, the vehicle is a railcar; The vehicle characterized in that the metal member is made of an aluminum alloy.

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