Metal foil laminate for use in current collecting layer and method for producing same

Abstract

To provide a metallic foil laminate which maintains adequate flexibility and strength and can achieve reduction in weight, and a method for manufacturing the metallic foil laminate.SOLUTION: There are provided a laminate which has a resin layer formed of a cured product of a resin composition containing the following components (A) to (C): (A) a thermosetting resin, (B) a thermoplastic resin, and (C) a curing agent, and metallic foil layers formed on both surfaces of the resin layer; and a method for manufacturing the laminate which includes a step (1) of arranging metallic foils having a carrier on one surface on both surfaces of a resin composition layer formed of a resin composition so that the other surface is brought into contact with both of the surfaces, a step (2) of thermosetting the resin composition layer, and a step (3) of peeling the carrier from the metallic foils on both of the surfaces of the resin composition layer, after thermosetting.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a metal foil laminate used in a current collecting layer and a method for producing the same. [Background technology]

[0002] As the number of devices incorporated into equipment continues to increase in the 5G and Beyond 5G era, the weight and size of the batteries that drive them tend to become heavier and larger. For this reason, it is desirable to reduce the weight while ensuring a certain current. For example, HAPS, which flies in the stratosphere equipped with solar panels and batteries and provides wireless communication services to the ground, and electric vehicles (EVs), require weight reduction, so it is essential to reduce the weight of the electrodes used in the batteries. This requirement can be met by reducing the thickness of the metal foil used as the current collecting layer, but there are technical limitations to making the metal foil thinner, and ultra-thin metal foils easily develop wrinkles and pinholes, making them difficult to apply to production processes.

[0003] For example, Patent Document 1 discloses a resin collector having a conductive resin layer and a metal layer, and as described in paragraph

[0017] , "Of the two main surfaces of the conductive layer, the metal layer may be provided only on one main surface of the conductive resin layer, or may be provided on both main surfaces of the conductive resin layer," the metal layer is not limited to one side, and may be provided on both sides. The thickness of the metal layer is 5 to less than 200 nm. On the other hand, as a polymer compound contained in the conductive resin layer, paragraph

[0012] exemplifies epoxy resin, but polyolefin-based is preferred, and there is no specific disclosure of a composition containing epoxy resin. In addition, the thickness of the resin layer described in the examples is as thick as 85 μm, and the copper foil layer is formed by a vacuum deposition method, and no mention is made of a manufacturing method using a transfer copper foil. In addition, Patent Document 1 exemplifies only a method of forming the metal layer by deposition for the manufacturing method of the resin collector. If a vacuum deposition method is applied directly to a thin resin layer, the heat generated during the vacuum deposition will cause the resin layer to shrink or wrinkle.

[0004] Patent Document 2 discloses a method for manufacturing a laminated current collector, the method including a preparation step of preparing a laminate in which a current collector including a resin layer is laminated, a hole forming step of forming holes in the stacking direction in the end regions of the laminate, a coating step of coating the inner walls of the holes with a conductive adhesive, a placement step of placing tabs on the upper and lower surface regions of the laminate including the hole portions, and a welding step of welding the laminate and the tabs. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-33066 A [Patent Document 2] Patent Publication No. 2021-97020 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in light of the above-mentioned circumstances, and an object of the present invention is to provide a metal foil laminate that can maintain appropriate flexibility and strength while achieving weight reduction, and a method for manufacturing the metal foil laminate. [Means for solving the problem]

[0007] Means for Solving the Problems The present inventors conducted intensive research to solve the above problems and discovered that by using the following configuration, it is possible to obtain a metal foil laminate that maintains appropriate flexibility and strength while achieving weight reduction, and thus completed the present invention.

[0008] That is, the present invention has the following features. [1] The following components (A) to (C): (A) Thermosetting resin; (B) a thermoplastic resin; and (C) Hardener A laminate comprising: a resin layer made of a cured product of a resin composition containing the above-mentioned formula (1); and metal foil layers formed on both sides of the resin layer. [2] The laminate according to [1], wherein (A) the thermosetting resin is an epoxy resin. [3] (B) The laminate according to [1] or [2], wherein the thermoplastic resin is a phenoxy resin. [4] The laminate according to any one of [1] to [3], wherein the resin composition further contains (D) a curing accelerator. [5] The laminate according to any one of [1] to [4], wherein the resin composition further contains (E) a conductive filler. [6] The laminate according to any one of [1] to [5], wherein the metal foil layer is a copper foil layer. [7] The laminate according to any one of [1] to [6], wherein the resin layer has a thickness of 3 to 60 μm. [8] A method for producing the laminate according to any one of [1] to [7], (1) a step of disposing a metal foil having a carrier on one side on both sides of a resin composition layer made of a resin composition such that the other side of the metal foil is in contact with the other side of the resin composition layer; (2) a step of thermally curing the resin composition layer; and (3) A step of peeling off the carrier from the metal foils on both sides of the resin composition layer after thermal curing. A manufacturing method comprising: [9] The method according to [8], wherein the step (1) comprises: (1a-1) applying a varnish of a resin composition to one side of a metal foil having a carrier on the other side, and drying the varnish to form a resin composition layer; and (1a-2) laminating a metal foil having a carrier on one side to the resin composition layer so that the other side of the metal foil is in contact with the resin composition layer.

[10] The method according to [8], wherein the step (1) comprises: (1b-1-1) applying a varnish of a resin composition to one side of a support and drying the varnish to form a resin composition layer; (1b-1-2) laminating a metal foil having a carrier on one side to the resin composition layer so that the other side of the metal foil contacts the resin composition layer; and (1b-1-3) peeling the support and laminating a metal foil having a carrier on one side to the exposed resin composition layer so that the other side of the metal foil contacts the resin composition layer.

[11] The method according to [8], wherein the step (1) comprises: (1b-2-1) applying a varnish of a resin composition to one side of a support and drying the varnish to form a resin composition layer; and (1b-2-2) peeling the support and laminating a metal foil having a carrier on one side to both sides of the resin composition layer so that the other side of the metal foil is in contact with the other side of the metal foil. Effect of the Invention

[0009] According to the present invention, it is possible to provide a metal foil laminate that is lighter and more flexible than when the current collecting layer is made from a single metal foil. In addition, according to the present invention, the current collecting layer can be freely designed by adjusting the thickness of the metal foil and the resin layer, imparting electrical conductivity to the resin layer, and the like. In addition, when a metal film is formed on an organic film by vapor deposition, the organic film shrinks or wrinkles due to heat during the process, so that it is necessary to make the organic film thick, and it has been difficult to make a laminate (current collecting layer) that can be manufactured thin. On the other hand, according to the present invention, it is possible to produce a laminate even if the organic layer (resin layer) is thin by forming a metal film by transfer. Furthermore, according to the present invention, the adhesion between the metal foil layer and the organic layer (resin layer) is increased by undergoing a process of thermal curing after forming metal foil layers on both sides of the resin composition layer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention will be described below based on preferred embodiments thereof. [Laminate] The laminate of the present invention comprises the following components (A) to (C): (A) Thermosetting resin; (B) a thermoplastic resin; and (C) Hardener and metal foil layers formed on both sides of the resin layer.

[0011] <(A) Thermosetting resin> The thermosetting resin used in the resin composition of the present invention is not particularly limited as long as the effect of the present invention is exhibited, and examples thereof include epoxy resins, cyanate ester resins, phenolic resins, bismaleimide-triazine resins, polyimide resins, acrylic resins, vinylbenzyl resins, etc., and among them, epoxy resins are preferred from the viewpoint of low-temperature curing properties, etc. These thermosetting resins may be used alone or in combination of two or more. The thermosetting resin acts as a crosslinking component in the resin composition.

[0012] The epoxy resin is not particularly limited as long as the effects of the present invention are exhibited, and any epoxy resin having two or more epoxy groups per molecule on average and having high transmittance can be used. For example, hydrogenated epoxy resins (hydrogenated bisphenol A type epoxy resins, hydrogenated bisphenol F type epoxy resins, etc.), fluorine-containing epoxy resins, linear aliphatic epoxy resins, cyclic aliphatic epoxy resins, bisphenol A type epoxy resins, biphenyl type epoxy resins, biphenyl aralkyl type epoxy resins, fluorene type epoxy resins, naphthol type epoxy resins, naphthalene type epoxy resins, bisphenol F type epoxy resins, epoxy resins containing a hydrocarbon chain in the main skeleton, phosphorus-containing epoxy resins, bisphenol S type epoxy resins, aromatic glycidylamine type epoxy resins (e.g., tetraglycidyl diazomethane type epoxy resins, etc.), etc. aminodiphenylmethane, triglycidyl-p-aminophenol, diglycidyl toluidine, diglycidyl aniline, etc.), alicyclic epoxy resins, phenol novolac type epoxy resins, alkylphenol type epoxy resins, cresol novolac type epoxy resins, bisphenol A novolac type epoxy resins, epoxy resins having a butadiene structure, diglycidyl ethers of bisphenols, diglycidyl ethers of naphthalenediol, diglycidyl ethers of phenols, diglycidyl ethers of alcohols, and alkyl substituted versions of these epoxy resins.

[0013] The epoxy resin may be used alone or in combination of two or more kinds. From the viewpoint of reactivity and the like, the epoxy equivalent of the epoxy resin is preferably 50 to 5,000 g / eq, more preferably 50 to 3,000 g / eq, further preferably 80 to 2,000 g / eq, and particularly preferably 100 to 1,500 g / eq. The "epoxy equivalent" is the number of grams (g / eq) of a resin containing 1 gram equivalent of epoxy groups, and is measured according to the method specified in JIS K 7236. The weight average molecular weight of the epoxy resin is preferably 5,000 or less.

[0014] The weight average molecular weight in the present invention is measured by gel permeation chromatography (GPC) method (polystyrene equivalent). Specifically, the weight average molecular weight by GPC method is measured at a column temperature of 40°C using Shimadzu Corporation's LC-9A / RID-6A as a measuring device, Showa Denko Corporation's Shodex K-800P / K-804L / K-804L as a column, and chloroform or the like as a mobile phase, and can be calculated using a calibration curve of standard polystyrene.

[0015] The epoxy resin may be liquid or solid, and liquid epoxy resin and solid epoxy resin may be used in combination. Here, "liquid" and "solid" refer to the state of the epoxy resin at room temperature (25°C) and normal pressure (1 atm). From the viewpoints of coatability, processability, and adhesiveness, it is preferable that 10 mass% or more of the total epoxy resin used is liquid epoxy resin. In one embodiment of the present invention, from the viewpoint of varnish viscosity, it is preferable to use liquid epoxy resin and solid epoxy resin in combination. The mass ratio of the liquid epoxy resin to the solid epoxy resin (liquid epoxy resin:solid epoxy resin) is preferably 1:2 to 1:0, more preferably 1:1.5 to 1:0.

[0016] "Hydrogenated epoxy resin" means an epoxy resin obtained by hydrogenating an aromatic ring-containing epoxy resin. The hydrogenation rate of the hydrogenated epoxy resin is preferably 50% or more, more preferably 70% or more. "Chain aliphatic epoxy resin" means an epoxy resin having a linear or branched alkyl chain or alkyl ether chain, and "cyclic aliphatic epoxy resin" means an epoxy resin having a cyclic aliphatic skeleton, such as a cycloalkane skeleton, in the molecule. "Alkylphenol epoxy resin" means an epoxy resin having a benzene ring skeleton having one or more alkyl groups and one or more hydroxyl groups as substituents, and the hydroxyl groups are converted to glycidyl ether groups.

[0017] As the hydrogenated epoxy resin, hydrogenated bisphenol A type epoxy resin and hydrogenated bisphenol F type epoxy resin are preferable. As long as the effects of the present invention are exhibited, epoxy resins other than the above-mentioned preferable epoxy resins may be contained in the thermosetting resin.

[0018] Examples of hydrogenated bisphenol A type epoxy resins include liquid hydrogenated bisphenol A type epoxy resins (e.g., "YX8000" (manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: about 205 g / eq), "Denacol EX-252" (manufactured by Nagase ChemteX Corporation, epoxy equivalent: about 213 g / eq)), solid hydrogenated bisphenol A type epoxy resins (e.g., "YX8040" (manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: about 1000 g / eq)), and the like.

[0019] As the fluorine-containing epoxy resin, for example, the fluorine-containing epoxy resin described in WO2011 / 089947 can be used.

[0020] Examples of the linear aliphatic epoxy resin include polyglycerol polyglycidyl ether (e.g., "Denacol EX-512" and "Denacol EX-521", manufactured by Nagase ChemteX Corporation), pentaerythritol polyglycidyl ether (e.g., "Denacol EX-411", manufactured by Nagase ChemteX Corporation), diglycerol polyglycidyl ether (e.g., "Denacol EX-421", manufactured by Nagase ChemteX Corporation), glycerol polyglycidyl ether (e.g., "Denacol EX-421", manufactured by Nagase ChemteX Corporation), and glycerol polyglycidyl ether (e.g., "Denacol EX-421", manufactured by Nagase ChemteX Corporation). glycidyl ether (e.g., "Denacol EX-313" and "Denacol EX-314", manufactured by Nagase ChemteX Corporation), trimethylolpropane polyglycidyl ether (e.g., "Denacol EX-321", manufactured by Nagase ChemteX Corporation), neopentyl glycol diglycidyl ether (e.g., "Denacol EX-211", manufactured by Nagase ChemteX Corporation), 1,6-hexanediol diglycidyl ether (e.g., "Denacol EX-211", manufactured by Nagase ChemteX Corporation), 2", Nagase ChemteX Corporation), ethylene glycol diglycidyl ether (e.g., "Denacol EX-810", "Denacol EX-811", Nagase ChemteX Corporation), diethylene glycol diglycidyl ether (e.g., "Denacol EX-850", "Denacol EX-851", Nagase ChemteX Corporation), polyethylene glycol diglycidyl ether (e.g., "Denacol EX-821", "Denacol EX-83 0", "Denacol EX-832", "Denacol EX-841", "Denacol EX-861", manufactured by Nagase ChemteX Corporation), propylene glycol diglycidyl ether (e.g., "Denacol EX-911", manufactured by Nagase ChemteX Corporation), polypropylene glycol diglycidyl ether (e.g., "Denacol EX-941", "Denacol EX-920", "Denacol EX-931", manufactured by Nagase ChemteX Corporation).

[0021] An example of a cyclic aliphatic epoxy resin is "EHPE-3150" manufactured by Daicel Chemical Industries, Ltd.

[0022] Examples of alkylphenol type epoxy resins include "HP-820" manufactured by DIC Corporation; "YDC-1312" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.; and "EX-146" manufactured by Nagase ChemteX Corporation.

[0023] The term "biphenyl aralkyl type epoxy resin" refers to an epoxy resin having a main chain in which a novolac structure and a divalent biphenyl structure are bonded. The term "fluorene type epoxy resin" refers to an epoxy resin having a fluorene skeleton. The term "fluorine-containing aromatic type epoxy resin" refers to a fluorine-containing epoxy resin having an aromatic ring. For example, the fluorine-containing aromatic type epoxy resin described in WO2011 / 089947 can be used.

[0024] Examples of bisphenol A type epoxy resins include "828EL", "1001" and "1004AF" manufactured by Mitsubishi Chemical Corporation, "840" and "850-S" manufactured by DIC Corporation, and "YD-128" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. Examples of mixtures of liquid bisphenol A type epoxy resins and liquid bisphenol F type epoxy resins include "ZX-1059" (epoxy equivalent: about 165 g / eq) manufactured by Nippon Steel Chemical Co., Ltd.

[0025] Examples of bisphenol F type epoxy resins include "807" manufactured by Mitsubishi Chemical Corporation, "830" manufactured by DIC Corporation, and "YDF-170" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.

[0026] Examples of commercially available epoxy resins containing a hydrocarbon chain in the main skeleton include ADEKA's "EP-4000S" and "EP-4010S" (modified bisphenol type epoxy resins); Mitsubishi Chemical's "YL7175-500", "YL7175-1000", "YL7410", and "YX7105" (modified bisphenol type epoxy resins); DIC's "EXA-4850", "EXA-4850-150", "EXA-4816", and "EXA-4822" (modified bisphenol type epoxy resins); Osaka Gas Chemicals' "EG-280"; Nagase ChemteX's "EX-830" (modified bisphenol type epoxy resin); and Mitsubishi Chemical's "YX7400" (polybutylene glycol diglycidyl ether).

[0027] Examples of phenol novolac type epoxy resins include "N-730A", "N-740", "N-770" and "N-775" manufactured by DIC Corporation; "152" and "154" manufactured by Mitsubishi Chemical Corporation.

[0028] Examples of biphenylaralkyl type epoxy resins include "NC-3000", "NC-3000L" and "NC-3100" manufactured by Nippon Kayaku Co., Ltd.

[0029] Examples of fluorene-type epoxy resins include "OGSOL PG-100," "CG-500EG-200," and "EG-280" manufactured by Osaka Gas Chemicals Co., Ltd.

[0030] From the viewpoint of imparting toughness to the resin composition, the content of the thermosetting resin in the resin composition of the present invention is preferably 10 to 70 mass%, more preferably 15 to 65 mass%, and even more preferably 20 to 60 mass%, relative to 100 mass% of the non-volatile content of the resin composition.

[0031] <(B) Thermoplastic resin> The thermoplastic resin used in the resin composition of the present invention is not particularly limited as long as the effects of the present invention are exhibited, and examples thereof include phenoxy resin, polyvinyl acetal resin, polyimide resin, polyamideimide resin, polyethersulfone resin, polysulfone resin, polyester resin, (meth)acrylic polymer, thermoplastic elastomer (styrene-isobutylene-styrene block copolymer (SIBS), styrene-ethylene-propylene-styrene block copolymer (SEPS), etc.), and among them, phenoxy resin is preferred from the viewpoint of good compatibility with thermosetting resins (especially epoxy resins). These thermoplastic resins may be used alone or in combination of two or more. By blending the thermoplastic resin, it becomes possible to form a film in a sheet-like form.

[0032] From the viewpoints of imparting flexibility to the resin composition layer formed from the resin composition, and of the coatability (prevention of repellency) of the resin composition varnish when forming the resin composition layer, the weight average molecular weight of the thermoplastic resin is preferably 15,000 or more, more preferably 20,000 or more. However, if this weight average molecular weight is too large, there is a tendency for the compatibility of the thermoplastic resin with the thermosetting resin (particularly, the epoxy resin) to decrease, etc. Therefore, this weight average molecular weight is preferably 1,000,000 or less, more preferably 800,000 or less.

[0033] The phenoxy resin may have an epoxy group, similarly to the epoxy resin, which is a thermosetting resin. The weight average molecular weight of the phenoxy resin is preferably 15,000 to 500,000, more preferably 20,000 to 300,000. The epoxy equivalent of the phenoxy resin having an epoxy group is preferably 5,000 to 30,000 g / eq, more preferably 6,000 to 25,000 g / eq, and further preferably 7,000 to 20,000 g / eq.

[0034] Suitable phenoxy resins include those having one or more skeletons selected from the group consisting of bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenolacetophenone skeleton, novolac skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, and norbornene skeleton. Only one type of phenoxy resin may be used, or two or more types may be used in combination.

[0035] Commercially available phenoxy resins include, for example, "YX7200B35" (manufactured by Mitsubishi Chemical Corporation: phenoxy resin containing a biphenyl skeleton), "YX7180BH40" (manufactured by Mitsubishi Chemical Corporation), "1256B40" (manufactured by Mitsubishi Chemical Corporation: phenoxy resin containing a bisphenol A skeleton), "YX6954BH35" (manufactured by Mitsubishi Chemical Corporation: phenoxy resin containing a bisphenol acetophenone skeleton), "FX-293" (manufactured by Nippon Steel Chemical & Material Corporation: resin containing a bisphenol A skeleton), and "FX-310" (manufactured by Nippon Steel Chemical & Material Corporation: resin containing a bisphenol A skeleton).

[0036] As the thermoplastic resin, polyester resin is also preferred from the viewpoint of good compatibility with thermosetting resins (particularly epoxy resins).

[0037] Examples of polyester resins include "UE-9200", "UE-3600", "UE-9800", "UE-9900", "UE-9820", "UE-3550", "UE-3380", "UE-3510", "UE-3400", "UE-3220", "UE-3500", and "UE-9100" (all manufactured by Unitika Ltd.: saturated copolymer polyester resins).

[0038] The content of the thermoplastic resin in the resin composition of the present invention is preferably 3 to 50 mass%, more preferably 4 to 45 mass%, and even more preferably 5 to 40 mass%, relative to 100 mass% of the nonvolatile content of the resin composition, from the viewpoints of forming the resin composition into a sheet-like film and suppressing cracking of the cured product.

[0039] <(C) Curing agent and (D) curing accelerator> The resin composition of the present invention contains a curing agent. The curing agent is not particularly limited as long as it has the function of curing the thermosetting resin. From the viewpoint of suppressing the amount of warping or thermal distortion, the curing agent is preferably one that can cure the thermosetting resin at a temperature of 140° C. or less (preferably 120° C. or less) (one that can be cured at low temperature). Only one type of curing agent may be used, or two or more types may be used in combination.

[0040] As the curing agent, examples of the curing agent for epoxy resin, which is preferable as a thermosetting resin, are given below, such as ionic liquid, acid anhydride compound, imidazole compound, tertiary amine compound, amine adduct compound, organic acid dihydrazide compound, organic phosphine compound, dicyandiamide compound, primary and secondary amine compounds, etc.

[0041] The curing agent is preferably one or more selected from an ionic liquid, an acid anhydride compound, an imidazole compound, a tertiary amine compound, and an amine adduct compound, and more preferably one or more selected from an ionic liquid, an acid anhydride compound, an imidazole compound, and a tertiary amine compound.

[0042] In particular, the curing agent in the present invention is preferably an ionic liquid capable of curing a thermosetting resin (particularly an epoxy resin) at a temperature of 140° C. or less (preferably 120° C. or less), i.e., a salt capable of melting in a temperature range of 140° C. or less (preferably 120° C. or less) and having a curing action for a thermosetting resin (particularly an epoxy resin). The ionic liquid is desirably used in a state in which it is uniformly dissolved in the thermosetting resin (particularly an epoxy resin).

[0043] The resin composition of the present invention may contain (D) a curing accelerator in addition to the curing agent for the purpose of adjusting the curing time. The curing accelerator may be used alone or in combination of two or more. As the curing accelerator, examples of the curing accelerator for epoxy resins that are preferred as thermosetting resins are given below. For example, dimethylurea compounds and the like can be mentioned.

[0044] Examples of the cation constituting the ionic liquid as a curing agent in the present invention include ammonium-based cations such as imidazolium ion, piperidinium ion, pyrrolidinium ion, pyrazonium ion, guanidinium ion, and pyridinium ion; phosphonium-based cations such as tetraalkylphosphonium cation (e.g., tetrabutylphosphonium ion, tributylhexylphosphonium ion, etc.); and sulfonium-based cations such as triethylsulfonium ion.

[0045] Examples of anions constituting the ionic liquid as a curing agent in the present invention include halide anions such as fluoride ion, chloride ion, bromide ion, and iodide ion; alkyl sulfate anions such as methanesulfonate ion; fluorine-containing compound anions such as trifluoromethanesulfonate ion, hexafluorophosphonate ion, trifluorotris(pentafluoroethyl)phosphonate ion, bis(trifluoromethanesulfonyl)imide ion, trifluoroacetate ion, and tetrafluoroborate ion; phenol ion, 2-methoxyphenol ion, 2,6-di-tert-butylphenol ion, and the like. acidic amino acid ions such as aspartate ion and glutamate ion; neutral amino acid ions such as glycine ion, alanine ion and phenylalanine ion; N-acylamino acid ions represented by the following general formula (1), such as N-benzoylalanine ion, N-acetylphenylalanine ion and N-acetylglycine ion; and carboxylate anions such as formate ion, acetate ion, decanoate ion, 2-pyrrolidone-5-carboxylate ion, α-lipoic acid ion, lactate ion, tartrate ion, hippurate ion, N-methylhippurate ion and benzoate ion.

[0046] [ka]

[0047] (wherein R is a linear or branched alkyl group having 1 to 5 carbon atoms or a substituted or unsubstituted phenyl group, and X represents the side chain of an amino acid.)

[0048] Examples of the amino acid in the formula (1) include aspartic acid, glutamic acid, glycine, alanine, phenylalanine, etc., and among these, glycine is preferred.

[0049] Among the above, the cation is preferably an ammonium-based cation or a phosphonium-based cation, more preferably an imidazolium ion or a phosphonium ion. More specifically, the imidazolium ion is a 1-ethyl-3-methylimidazolium ion, a 1-butyl-3-methylimidazolium ion, a 1-propyl-3-methylimidazolium ion, or the like.

[0050] The anion is preferably a phenol anion, an N-acylamino acid ion represented by the general formula (1) or a carboxylate anion, and more preferably an N-acylamino acid ion or a carboxylate anion.

[0051] Specific examples of phenolic anions include 2,6-di-tert-butylphenol ion.Specific examples of carboxylate anions include acetate ion, decanoic acid ion, 2-pyrrolidone-5-carboxylate ion, formate ion, α-lipoic acid ion, lactate ion, tartrate ion, hippuric acid ion, N-methylhippuric acid ion, etc., among which acetate ion, 2-pyrrolidone-5-carboxylate ion, formate ion, lactate ion, tartrate ion, hippuric acid ion, N-methylhippuric acid ion are preferred, and acetate ion, decanoic acid ion, N-methylhippuric acid ion, and formate ion are particularly preferred. Specific examples of the N-acylamino acid ion represented by general formula (1) include an N-benzoylalanine ion, an N-acetylphenylalanine ion, an aspartic acid ion, a glycine ion, and an N-acetylglycine ion. Among these, the N-benzoylalanine ion, the N-acetylphenylalanine ion, and the N-acetylglycine ion are preferred, and the N-acetylglycine ion is particularly preferred.

[0052] Specific examples of ionic liquids include 1-butyl-3-methylimidazolium lactate, tetrabutylphosphonium-2-pyrrolidone-5-carboxylate, tetrabutylphosphonium acetate, tetrabutylphosphonium decanoate, tetrabutylphosphonium trifluoroacetate, tetrabutylphosphonium α-lipoate, tetrabutylphosphonium formate, tetrabutylphosphonium lactate, bis(tetrabutylphosphonium)tartrate, tetrabutylphosphonium hippurate, tetrabutylphosphonium N-methylhippurate, benzoyl-DL-alanine tetrabutylphosphonium salt, N-acetylphenylalanine tetrabutylphosphonium salt, 2,6-di-tert-butylphenol tetrabutylphosphonium salt, monotetrabutylphosphonium L-aspartate, glycine tetrabutylphosphonium salt, tetrabutylphosphonium ... tetrabutylphosphonium salt, N-acetylglycine tetrabutylphosphonium salt, 1-ethyl-3-methylimidazolium lactate, 1-ethyl-3-methylimidazolium acetate, formate 1-ethyl-3-methylimidazolium salt, hippuric acid 1-ethyl-3-methylimidazolium salt, N-methylhippuric acid 1-ethyl-3-methylimidazolium salt, tartrate bis(1-ethyl-3-methylimidazolium) salt, N-acetylglycine 1-ethyl-3-methylimidazolium salt are preferred, and tetrabutylphosphonium decanoate, N-acetylglycine tetrabutylphosphonium salt, 1-ethyl-3-methylimidazolium acetate, formate 1-ethyl-3-methylimidazolium salt, hippuric acid 1-ethyl-3-methylimidazolium salt, N-methylhippuric acid 1-ethyl-3-methylimidazolium salt are particularly preferred.

[0053] The synthesis method of the ionic liquid includes, but is not limited to, an anion exchange method in which a precursor composed of a cationic portion such as an alkylimidazolium, alkylpyridinium, alkylammonium, and alkylsulfonium ion and an anionic portion containing a halogen is reacted with NaBF4, NaPF6, CF3SO3Na, LiN(SO2CF3)2, etc., an acid ester method in which an amine-based substance is reacted with an acid ester to introduce an alkyl group while an organic acid residue becomes a counter anion, and a neutralization method in which an amine is neutralized with an organic acid to obtain a salt, etc. In the neutralization method using an anion, a cation, and a solvent, an anion and a cation are used in equal amounts, and the solvent in the obtained reaction liquid is distilled off and the liquid can be used as it is, or an organic solvent (methanol, toluene, ethyl acetate, acetone, etc.) can be added to concentrate the liquid.

[0054] Examples of the acid anhydride compound as the curing agent in the present invention include tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, dodecenylsuccinic anhydride, etc. Specific examples of the acid anhydride compound include Rikacid TH, TH-1A, HH, MH, MH-700, MH-700G (all manufactured by New Japan Chemical Co., Ltd.), etc.

[0055] Examples of the imidazole compound as a curing agent in the present invention include 1H-imidazole, 2-methyl-imidazole, 2-phenyl-4-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-ethyl-4-methyl-imidazole, 2-undecylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 2,4-diamino-6-(2'-undecylimidazolyl-(1'))-ethyl-s-triazine, 2-phenyl-4,5-bis(hydroxymethyl)-imidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 2-phenyl-imidazole, 2-dodecyl- Examples of the imidazole compound include imidazole, 2-heptadecylimidazole, 1,2-dimethyl-imidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,4-diamino-6-(2'-methylimidazolyl-(1')-ethyl-s-triazine, and 2,4-diamino-6-(2'-methylimidazolyl-(1'))-ethyl-s-triazine isocyanuric acid adduct. Specific examples of the imidazole compound include Curesol 2MZ, 2P4MZ, 2E4MZ, 2E4MZ-CN, C11Z, C11Z-CN, C11Z-CNS, C11Z-A, 2PHZ, 1B2MZ, 1B2PZ, 2PZ, C17Z, 1.2DMZ, 2P4MHZ-PW, 2MZ-A, and 2MA-OK (all manufactured by Shikoku Chemical Industry Co., Ltd.).

[0056] Specific examples of the tertiary amine compound as the curing agent in the present invention include DBN (1,5-diazabicyclo[4.3.0]non-5-ene), DBU (1,8-diazabicyclo[5.4.0]undec-7-ene), 2-ethylhexanoate of DBU, phenol salt of DBU, p-toluenesulfonate of DBU, U-CAT SA 102 (manufactured by San-Apro Co., Ltd.: octylate of DBU), DBU formate and other DBU-organic acid salts, tris(dimethylaminomethyl)phenol (TAP), and the like.

[0057] Specific examples of the dimethylurea compound as the curing accelerator in the present invention include DCMU (3-(3,4-dichlorophenyl)-1,1-dimethylurea), aromatic dimethylurea such as U-CAT3512T (manufactured by San-Apro Ltd.), and aliphatic dimethylurea such as U-CAT3503N (manufactured by San-Apro Ltd.). Among these, aromatic dimethylurea is preferably used from the viewpoint of curability.

[0058] Examples of the amine adduct compound as a curing agent in the present invention include epoxy adduct compounds obtained by stopping the addition reaction of a tertiary amine to an epoxy resin midway, etc. Specific examples of the amine adduct compounds include Amicure PN-23, Amicure MY-24, Amicure PN-D, Amicure MY-D, Amicure PN-H, Amicure MY-H, Amicure PN-31, Amicure PN-40, Amicure PN-40J (all manufactured by Ajinomoto Fine-Techno Co., Ltd.), etc.

[0059] Specific examples of the organic acid dihydrazide compound as the curing agent in the present invention include Amicure VDH-J, Amicure UDH, and Amicure LDH (all manufactured by Ajinomoto Fine-Techno Co., Ltd.).

[0060] Examples of the organic phosphine compound as the curing agent in the present invention include triphenylphosphine, tetraphenylphosphonium tetra-p-tolylborate, tetraphenylphosphonium tetraphenylborate, tri-tert-butylphosphonium tetraphenylborate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, butyltriphenylphosphonium thiocyanate, triphenylphosphine triphenylborane, etc. Specific examples of the organic phosphine compound include TPP, TPP-MK, TPP-K, TTBuPK, TPP-SCN, TPP-S (manufactured by Hokko Chemical Industry Co., Ltd.), etc.

[0061] The dicyandiamide compound as the curing agent in the present invention may, for example, be dicyandiamide. Specific examples of the dicyandiamide compound include DICY7 and DICY15 (both manufactured by Mitsubishi Chemical Corporation), which are finely ground dicyandiamide products.

[0062] Examples of primary and secondary amine compounds as the curing agent in the present invention include aliphatic amines such as diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, trimethylhexamethylenediamine, 2-methylpentamethylenediamine, 1,3-bisaminomethylcyclohexane, dipropylenediamine, diethylaminopropylamine, bis(4-aminocyclohexyl)methane, norbornenediamine, and 1,2-diaminocyclohexane, alicyclic amines such as N-aminoethylpiperazine and 1,4-bis(3-aminopropyl)piperazine, and aromatic amines such as diaminodiphenylmethane, m-phenylenediamine, m-xylylenediamine, metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, and diethyltoluenediamine. Specific examples of primary and secondary amine compounds include Kayahard AA (manufactured by Nippon Kayaku Co., Ltd.: 4,4'-diamino-3,3'-dimethyldiphenylmethane).

[0063] The content of the curing agent in the resin composition of the present invention is preferably 0.1 to 40 mass%, more preferably 0.5 to 38 mass parts, and even more preferably 1 to 35 mass parts, based on 100 mass% of the nonvolatile content of the resin composition. If the content is less than 0.1 mass%, sufficient curing may not be obtained, and if the content is more than 40 mass%, the storage stability of the resin composition may be impaired. When an ionic liquid is used as a curing agent, the amount of the ionic liquid is preferably 0.1 to 20 mass%, more preferably 0.5 to 18 mass%, and even more preferably 1 to 15 mass%, based on 100 mass% of the nonvolatile content of the resin composition.

[0064] When the resin composition of the present invention contains a curing accelerator, the content is preferably 0.05 to 10 mass%, more preferably 0.1 to 8 mass%, and even more preferably 0.5 to 5 mass%, based on 100 mass% of the nonvolatile content of the resin composition. If the content is less than 0.05 mass%, curing tends to be slow and the heat curing time tends to be long, and if it exceeds 10 mass%, the storage stability of the resin composition tends to decrease.

[0065] The resin composition of the present invention is preferably used in combination with a curing agent and a curing accelerator. As a combination of the curing agent and the curing accelerator, a combination of at least one selected from an ionic liquid, an acid anhydride compound, an imidazole compound, a tertiary amine compound, and an amine adduct compound and a dimethylurea compound is preferable.

[0066] <(E) Conductive filler> The resin composition of the present invention may further contain a conductive filler in order to improve the conductivity of the laminate. Examples of the conductive filler include carbon black, graphite, carbon nanotubes, metal powders (nickel, aluminum, stainless steel (SUS), silver, copper, zinc, titanium, etc.), metal oxide powders (tin oxide, indium oxide, zinc oxide, etc.), and metal-coated powders (inorganic and organic materials coated with a conductive material, etc.). Carbon black is preferred from the viewpoint of weight reduction. As carbon black, acetylene black, oil furnace black, gas furnace black, lamp black, channel black, etc. are preferred.Specific examples of carbon black include Raven 760 ULTRA, Raven 780 ULTRA, Raven 790 ULTRA, Raven 1060 ULTRA, Raven 1080 ULTRA, Raven 1170, Raven 1190 ULTRA II, Raven 1200, Raven 1250, Raven 1255, Raven 1500, Raven 2000, Raven 2500 ULTRA, Raven 3500, Raven 5000 ULTRA II, Raven 5250, Raven 5750, and Raven 7000 (all manufactured by Columbia Carbon Corporation); Monarch 700, Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 1400, Regal 1330R, Regal 1400R, Regal 1660R, and Mogul L (all manufactured by Cabot Corporation); Color Black FW1, Color Black FW2, Color Black FW2V, Color Black FW200, Color Black S150, Color Black S160, Color Black S170, Printex 35, Printex U, Printex V, Printex 140U, Printex 140V, SpecIal Black 4, SpecIal Black 4A, SpecIal Black 5, Special Black 6 (all manufactured by Degussa Corporation); MA7, MA8, MA100, MA600, MCF-88, No. 25, No. 33, No. 40, No. 47, No. 52, No. 900, No. 2300 (all manufactured by Mitsubishi Chemical Corporation); etc. Examples of carbon nanotubes include single-wall carbon nanotubes (SWCNT), multi-wall carbon nanotubes (MWCNT) such as double-wall carbon nanotubes (DWCNT), etc. The conductive filler may be used alone or in combination of two or more kinds.

[0067] From the viewpoint of the film, the particle diameter of the conductive filler is preferably 5 μm or less, more preferably 3 μm or less. For example, the particle diameter of the primary particles can be 0.001 to 3 μm, more preferably 0.005 to 2 μm. In the present invention, the "particle diameter" is measured using a laser diffraction particle size distribution meter, and is defined as the particle diameter (median diameter) at which the relative particle amount is 50% (50% of the total particle amount, the particle diameter at the midpoint of the particle amount when the total particle amount and particle diameter are graphed).

[0068] The content of the conductive filler in the resin composition of the present invention is preferably 5 to 90 mass %, and more preferably 10 to 80 mass %, based on 100 mass % of the nonvolatile content of the resin composition, from the viewpoint of electrical conductivity.

[0069] <Other additives> The resin composition of the present invention may further contain other additives different from the above-mentioned components as long as the effects of the present invention are exhibited. Examples of such additives include silane coupling agents; organic fillers such as rubber particles, silicone powder, nylon powder, and fluororesin powder; thickeners such as orben and benton; silicone-based, fluorine-based, and polymer-based defoamers or leveling agents; adhesion-imparting agents such as triazole compounds, thiazole compounds, triazine compounds, and porphyrin compounds; flame retardants such as phosphorus-based compounds and metal hydroxides; and the like.

[0070] <Method of producing resin composition> The method for producing the resin composition of the present invention is not particularly limited, and examples thereof include a method in which the above-mentioned blending components are mixed, if necessary, with a solvent or the like, using a kneading roller or a rotary mixer.

[0071] <Resin layer> In the laminate of the present invention, the resin layer is made of a cured product of the resin composition described above. The resin layer can be formed, for example, by the process described in the following [Laminate manufacturing method]. From the viewpoint of weight reduction and electrical resistance value, the thickness of the resin layer is preferably 60 μm or less, more preferably 50 μm or less, even more preferably 40 μm or less, even more preferably 30 μm or less, and particularly preferably 20 μm or less. From the viewpoint of layer formation, the lower limit of the thickness of the resin layer is preferably 3 μm or more, more preferably 5 μm or more. In one embodiment of the present invention, the thickness of the resin layer is preferably 3 to 60 μm, more preferably 5 to 50 μm.

[0072] <Metal foil layer> In the laminate of the present invention, the metal foil layer is formed on both sides of the resin layer. Examples of metals include copper, nickel, aluminum, stainless steel (SUS), silver, and titanium, and copper and nickel are preferred from the viewpoint of durability against an electrolytic solution. The metal foil layer can be formed, for example, by the process described in the following [Manufacturing method of laminate]. The thickness of the metal foil layer is preferably 0.005 to 2 μm, more preferably 0.01 to 1.5 μm, and even more preferably 0.02 to 1 μm, from the viewpoint of weight reduction and electrical resistance value.

[0073] [Method of manufacturing laminate] The method for producing the laminate of the present invention comprises the steps of: (1) a step of disposing a metal foil having a carrier on one side on both sides of a resin composition layer made of a resin composition such that the other side of the metal foil is in contact with the other side of the resin composition layer; (2) a step of thermally curing the resin composition layer; and (3) A step of peeling off the carrier from the metal foils on both sides of the resin composition layer after thermal curing. Includes. By using a metal foil having a carrier on one side (hereinafter, sometimes referred to as "metal foil with carrier"), the metal foil can be transferred to the resin composition layer, so that it is possible to form an extremely thin metal foil layer on the resin layer. Note that the resin composition in the explanation of [Method for producing a laminate] is the resin composition explained above.

[0074] The carrier of the metal foil with carrier is not particularly limited as long as the metal foil can be transferred to the resin composition layer, and examples thereof include plastic films such as polyolefins such as polyethylene, polypropylene, and polyvinyl chloride, cycloolefin polymers, polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate, polycarbonates, and polyimides. As the plastic film, PET is particularly preferred. The surface of the carrier having the metal foil may be subjected to a release treatment using a silicone resin-based release agent, an alkyd resin-based release agent, a fluorine resin-based release agent, or the like, a matte treatment, a corona treatment, or the like. In the present invention, when the carrier has a release layer, the release layer is also considered to be a part of the carrier. The thickness of the carrier is not particularly limited, but is preferably 20 to 200 μm, more preferably 20 to 125 μm, from the viewpoint of handleability and the like.

[0075] <Process (1)> In one embodiment of the present invention, step (1) comprises the steps of: (1a-1) a step of applying a varnish of a resin composition to one side of a metal foil having a carrier on the other side, and drying the other side to form a resin composition layer; and (1a-2) a step of laminating a metal foil having a carrier on one side to the resin composition layer so that the other side of the metal foil is in contact with the resin composition layer.

[0076] Step (1a-1) is carried out, for example, by coating a resin composition prepared by blending an organic solvent into a varnish on the metal foil of a carrier-attached metal foil, and drying the resulting coating by heating or blowing hot air, etc., to form a resin composition layer on the metal foil.

[0077] Examples of organic solvents include ketones such as acetone, methyl ethyl ketone (hereinafter also abbreviated as "MEK"), cyclohexanone, etc., acetate esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, carbitol acetate, etc., carbitols such as cellosolve, butyl carbitol, etc., aromatic hydrocarbons such as toluene, xylene, etc., dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc. Any one of the organic solvents may be used alone, or two or more of them may be used in combination.

[0078] The drying conditions are not particularly limited, but typically a temperature of about 50 to 100° C. for about 3 to 15 minutes is suitable.

[0079] The thickness of the resin composition layer after drying is usually in the range of 3 μm to 200 μm, preferably 5 μm to 100 μm, and more preferably 5 μm to 50 μm.

[0080] Step (1a-2) is carried out, for example, by laminating a metal foil of a carrier-attached metal foil to the resin composition layer formed in step (1a-1) using a roll laminator, a vacuum laminator or the like by a batch method, a continuous method with a roll or the like.

[0081] In another embodiment of the present invention, step (1) comprises the steps of: (1b-1-1) a step of applying a varnish of a resin composition to one side of a support and drying it to form a resin composition layer, (1b-1-2) a step of laminating a metal foil having a carrier on one side to the resin composition layer so that the other side of the metal foil is in contact with the resin composition layer, and (1b-1-3) a step of peeling off the support and laminating a metal foil having a carrier on one side to the exposed resin composition layer so that the other side of the metal foil is in contact with the resin composition layer.

[0082] Step (1b-1-1) can be carried out, for example, by forming a resin composition layer on a support in the same manner as in step (1a-1). Examples of the support used in this step include plastic films such as polyolefins such as polyethylene, polypropylene, and polyvinyl chloride, cycloolefin polymers, polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate, polycarbonates, and polyimides. As the plastic film, PET is particularly preferred. The support may also be a metal foil such as aluminum foil, stainless steel foil, and copper foil. The support may be subjected to a release treatment with a silicone resin-based release agent, an alkyd resin-based release agent, a fluorine resin-based release agent, or the like, a matte treatment, a corona treatment, or the like on the surface on which the resin composition layer is formed. In the present invention, when the support has a release layer, the release layer is also considered to be a part of the support. The thickness of the support is not particularly limited, but is preferably 20 to 200 μm, more preferably 20 to 125 μm, from the viewpoint of handleability and the like.

[0083] The step (1b-1-2) can be carried out, for example, in the same manner as in the above step (1a-2), by laminating the metal foil of the carrier-attached metal foil to the resin composition layer.

[0084] Step (1b-1-3) can be carried out, for example, by peeling off the support and then laminating a metal foil of a carrier-attached metal foil to the exposed resin composition layer in the same manner as in step (1a-2) above.

[0085] In yet another embodiment of the present invention, step (1) comprises the steps of: (1b-2-1) a step of applying a varnish of a resin composition to one side of a support and drying the varnish to form a resin composition layer; and (1b-2-2) a step of peeling off the support and laminating a metal foil having a carrier on one side to both sides of the resin composition layer so that the other side of the metal foil is in contact with the other side of the metal foil.

[0086] The step (1b-2-1) can be carried out, for example, in the same manner as in the above step (1b-1-1), by forming a resin composition layer on a support.

[0087] The step (1b-2-2) can be carried out, for example, by peeling off the support and then laminating the metal foil of the carrier-attached metal foil to both sides of the resin composition layer in the same manner as in the above step (1a-2).

[0088] <Process (2)> The heat curing can be carried out by, for example, heating and pressing using a press, a vacuum laminator, etc. From the viewpoint of adhesion between the resin composition layer and the metal foil, the temperature is preferably 70°C or more and less than 150°C, more preferably 80°C or more and less than 150°C, and the pressure is preferably 0.05 MPa or more, more preferably 0.1 MPa or more. This process can form a resin layer made of a cured product of the resin composition.

[0089] <Process (3)> After thermal curing, the carrier can be peeled off from the metal foil on both sides of the resin composition layer (the cured resin composition layer, i.e., the resin layer consisting of the cured product of the resin composition) to obtain a laminate having the resin layer of the present invention and metal foil layers formed on both sides of the resin layer (a laminate having a laminate structure of metal foil layer / resin layer / metal foil layer).

[0090] [Application] The laminate of the present invention can be suitably used, for example, as a current collecting layer, particularly as a current collecting layer for the negative electrode of a battery. EXAMPLES

[0091] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples, and can be practiced with appropriate modifications within the scope of the above and below spirit, all of which are included in the technical scope of the present invention. Note that "parts" and "%" in the amounts of components and copolymerized units mean "parts by mass" and "% by mass", respectively, unless otherwise specified.

[0092] <Ingredients> The components used in the examples and comparative examples are shown below. (A) Component: A mixture of liquid bisphenol A type epoxy resin and liquid bisphenol F type epoxy resin ("ZX-1059" manufactured by Nippon Steel Chemical Co., Ltd., epoxy equivalent: approx. 165g / eq) Flexible epoxy resin (Mitsubishi Chemical "YX7105") (B) Ingredients: Phenoxy resin solution (Mitsubishi Chemical "YX7200B35", solvent: MEK, non-volatile content: 35%, epoxy equivalent: approx. 8000g / eq) Phenoxy resin solution (Mitsubishi Chemical "YX7180BH40", solvent: mixed solvent of MEK and amine, non-volatile content: 40%, epoxy equivalent: approx. 9000g / eq) Phenoxy resin solution (Mitsubishi Chemical "1256B40", solvent: MEK, non-volatile content: 40%, epoxy equivalent: approx. 7800g / eq) (C) Ingredients: "2E4MZ" manufactured by Shikoku Chemical Industry Co., Ltd. (D) Ingredients: San-Apro "U-CAT3512T" (E) Ingredients: Carbon black (average particle size 50 nm, Mitsubishi Chemical "#20") Carbon black (average particle size 20 nm, Mitsubishi Chemical Corporation "MA600") Comparative Example Ingredients: "Novatec MA3" (Polypropylene (PP)) manufactured by Japan Polypropylene Corporation "Novatec UF230" (Polyethylene (PE)) manufactured by Japan Polyethylene Corporation

[0093] <Example 1> A varnish having the blending ratio shown in the table below was prepared by the following procedure, and a laminate was prepared using the obtained varnish. The amount (parts) of each component used in the table below indicates the amount of non-volatile content of each component in the varnish. Specifically, a mixture of liquid bisphenol A type epoxy resin and liquid bisphenol F type epoxy resin ("ZX-1059" manufactured by Nippon Steel Chemical Co., Ltd.), a phenoxy resin solution ("1256B40" manufactured by Mitsubishi Chemical Co., Ltd.), and carbon black (average particle size 50 nm, "#20" manufactured by Mitsubishi Chemical Co., Ltd.) were blended and uniformly dispersed in a high-speed rotating mixer to obtain a mixture. Furthermore, a curing accelerator ("U-CAT3512T" manufactured by San-Apro Co., Ltd.) and a curing agent ("2E4MZ" manufactured by Shikoku Kasei Kogyo Co., Ltd.) were blended in the obtained mixture and uniformly dispersed in a high-speed rotating mixer to obtain a varnish of a resin composition.

[0094] The obtained varnish was uniformly applied using a die coater onto the release-treated surface of a support (a polyethylene terephthalate film treated with a non-silicone release agent, thickness 38 μm, hereinafter abbreviated as "release PET film") so that the thickness of the resin composition layer after drying would be 10 μm. After drying at 80°C for 10 minutes, a release PET film was attached as a protective film to the surface of the formed resin composition layer so that its release-treated surface was in contact with the resin composition layer, thereby obtaining a sheet having a laminated structure of support / resin composition layer / protective film.

[0095] The protective film of the obtained sheet was peeled off, and a copper foil with a carrier (carrier: PET; thickness: 38 μm; copper foil thickness: 0.1 μm) was laminated to the exposed resin composition layer. Next, the support was peeled off, and a copper foil with a carrier (carrier: PET; thickness: 38 μm; copper foil thickness: 0.1 μm) was laminated to the exposed resin composition layer. The resulting mixture was heated and pressed at 80° C. and 0.3 MPa, and heated in an oven at 100° C. for 60 minutes to thermally cure the resin composition layer, thereby producing a laminate having a copper foil layer / resin layer / copper foil layer laminate structure.

[0096] <Example 2> A laminate having a copper foil layer / resin layer / copper foil layer laminate structure was produced in the same manner as in Example 1, except that the amount of the mixture of liquid bisphenol A type epoxy resin and liquid bisphenol F type epoxy resin ("ZX-1059" manufactured by Nippon Steel Chemical Co., Ltd.) used was changed from 80 parts to 40 parts, and 40 parts of a flexible epoxy resin ("YX7105" manufactured by Mitsubishi Chemical Corporation) was further added.

[0097] <Example 3> A laminate having a copper foil layer / resin layer / copper foil layer laminate structure was produced in the same manner as in Example 1, except that the amount of phenoxy resin solution ("1256B40" manufactured by Mitsubishi Chemical Corporation) used was changed from 120 parts to 60 parts, and 60 parts of phenoxy resin solution ("YX7200B35" manufactured by Mitsubishi Chemical Corporation) was further blended.

[0098] <Example 4> A laminate having a copper foil layer / resin layer / copper foil layer laminate structure was produced in the same manner as in Example 1, except that the amount of phenoxy resin solution ("1256B40" manufactured by Mitsubishi Chemical Corporation) used was changed from 120 parts to 60 parts, and 60 parts of phenoxy resin solution ("YX7180BH40" manufactured by Mitsubishi Chemical Corporation) was further blended.

[0099] <Example 5> A laminate having a copper foil layer / resin layer / copper foil layer structure was produced in the same manner as in Example 1, except that the carbon black (average particle size 50 nm, Mitsubishi Chemical Corporation's "#20") was changed to carbon black (average particle size 20 nm, Mitsubishi Chemical Corporation's "MA600").

[0100] <Example 6> A laminate having a copper foil layer / resin layer / copper foil layer structure was produced in the same manner as in Example 1, except that the amount of carbon black (average particle size 50 nm, Mitsubishi Chemical Corporation's "#20") used was changed from 24 parts to 10 parts.

[0101] <Example 7> A laminate having a copper foil layer / resin layer / copper foil layer structure was produced in the same manner as in Example 1, except that the amount of carbon black (average particle size 50 nm, Mitsubishi Chemical Corporation's "#20") used was changed from 24 parts to 50 parts.

[0102] <Example 8> A laminate having a copper foil layer / resin layer / copper foil layer structure was produced in the same manner as in Example 1, except that the thickness of the resin composition layer after drying was changed from 10 μm to 20 μm.

[0103] <Example 9> A laminate having a laminated structure of copper foil layer / resin layer / copper foil layer was produced in the same manner as in Example 1, except that the thickness of the copper foil was changed from 0.1 μm to 1 μm.

[0104] <Example 10> A laminate having a copper foil layer / resin layer / copper foil layer laminate structure was produced in the same manner as in Example 1, except that the amount of the mixture of liquid bisphenol A epoxy resin and liquid bisphenol F epoxy resin ("ZX-1059" manufactured by Nippon Steel Chemical Co., Ltd.) used was changed from 80 parts to 60 parts.

[0105] <Example 11> A laminate having a copper foil layer / resin layer / copper foil layer laminate structure was produced in the same manner as in Example 1, except that the amount of the mixture of liquid bisphenol A epoxy resin and liquid bisphenol F epoxy resin ("ZX-1059" manufactured by Nippon Steel Chemical Co., Ltd.) used was changed from 80 parts to 100 parts.

[0106] <Example 12> A laminate having a copper foil layer / resin layer / copper foil layer laminate structure was produced in the same manner as in Example 1, except that the amount of phenoxy resin solution ("1256B40" manufactured by Mitsubishi Chemical Corporation) used was changed from 120 parts to 80 parts.

[0107] <Example 13> A laminate having a copper foil layer / resin layer / copper foil layer laminate structure was produced in the same manner as in Example 1, except that the amount of phenoxy resin solution ("1256B40" manufactured by Mitsubishi Chemical Corporation) used was changed from 120 parts to 160 parts.

[0108] <Example 14> A laminate having a copper foil layer / resin layer / copper foil layer structure was produced in the same manner as in Example 1, except that the formulation was changed to exclude carbon black (average particle size 50 nm, Mitsubishi Chemical Corporation's "#20")

[0109] <Comparative Example 1> Instead of a laminate having a copper foil layer / resin layer / copper foil layer laminate structure, a commercially available copper foil (thickness: 12 μm) was used.

[0110] <Comparative Example 2> Instead of a laminate having a copper foil layer / resin layer / copper foil layer laminate structure, a commercially available PET film (thickness: 12 μm) was used.

[0111] <Comparative Example 3> Polypropylene (Novatec MA3 manufactured by Japan Polypropylene) and carbon black (average particle size 50 nm, #20 manufactured by Mitsubishi Chemical Corporation) were melt-blended and gelled in a high-temperature extruder. The mixture was then rolled with a roll onto the release-treated surface of a release PET film so that the resin composition layer had a thickness of 10 μm, to obtain a sheet having a laminated structure of a support body / resin composition layer.

[0112] A copper foil with a carrier (carrier: PET; thickness: 38 μm; copper foil thickness: 0.1 μm) was laminated to the resin composition layer of the obtained sheet, and then the support was peeled off. A copper foil with a carrier (carrier: PET; thickness: 38 μm; copper foil thickness: 0.1 μm) was laminated to the exposed resin composition layer, and heated and pressed at 80° C. and 0.3 MPa to produce a laminate having a copper foil layer / resin layer / copper foil layer laminate structure.

[0113] <Comparative Example 4> Polyethylene (Novatec UF230 manufactured by Japan Polyethylene Corporation) and carbon black (average particle size 50 nm, #20 manufactured by Mitsubishi Chemical Corporation) were melt-blended and passed through an extruder film molding machine to extrude the resin composition into a film on the release-treated surface of a release PET film so that the resin composition layer had a thickness of 10 μm, obtaining a sheet having a laminated structure of a support body / resin composition layer.

[0114] A copper foil with a carrier (carrier: PET; thickness: 38 μm; copper foil thickness: 0.1 μm) was laminated to the resin composition layer of the obtained sheet, and then the support was peeled off. A copper foil with a carrier (carrier: PET; thickness: 38 μm; copper foil thickness: 0.1 μm) was laminated to the exposed resin composition layer, and heated and pressed at 80° C. and 0.3 MPa to produce a laminate having a copper foil layer / resin layer / copper foil layer laminate structure.

[0115] <Comparative Example 5> An attempt was made to produce a laminate having a copper foil layer / resin layer / copper foil layer laminate structure in the same manner as in Example 1, except that copper foil layers (thickness: 1 μm) were formed on both sides of the resin composition layer of the obtained sheet by a vapor deposition process.

[0116] The laminates having a copper foil layer / resin layer / copper foil layer structure obtained in the examples and comparative examples were evaluated by the following methods.

[0117] <Evaluation of film properties> The state of the laminates having a copper foil layer / resin layer / copper foil layer structure obtained in the examples and comparative examples was evaluated as follows. 〇 (Good): Film (resin layer) formation is good and it can be used as a current collecting layer. × (bad): A film (resin layer) can be formed, but it is too tacky to be used as a current collecting layer, or a film (resin layer) can be formed, but the adhesion to the copper foil layer is weak and it cannot be used as a current collecting layer, or film formation is not possible, or the copper foil layer is too thin during the deposition process to maintain its strength and film formation is not possible.

[0118] <Weight Rating> The laminates having a copper foil layer / resin layer / copper foil layer structure obtained in the examples and comparative examples were cut into 5 cm squares, and the weight per unit area was calculated using a precision balance. ○(Good): Weight per unit area is 5mg / cm 2 less than × (defective): Weight per unit area is 5mg / cm 2 End

[0119] <Evaluation of resistance value> The laminates having a copper foil layer / resin layer / copper foil layer structure obtained in the examples and comparative examples were cut into 5 cm squares, and the resistance value of the copper foil layer surface was measured using a low resistivity meter [MCP-T700, manufactured by Mitsubishi Chemical Analytech Co., Ltd.] using the four-point probe method. The evaluation was made as follows. ○(Good): Resistance value is less than 1Ω / □ × (Fail): Unable to measure due to resistance value of 1Ω / □ or higher or high resistance

[0120] <Evaluation of Adhesion> The laminates having a copper foil layer / resin layer / copper foil layer structure obtained in the Examples and Comparative Examples were cut into 5 cm squares, one of the copper foil layers was peeled off, and glass ("OA-10G" manufactured by Nippon Electric Glass Co., Ltd.) was attached to the exposed resin layer to prepare evaluation samples having a glass / resin layer / copper foil layer laminate structure. A cross-cut test was performed with reference to JIS K5600-5-6, and the results were judged as follows. ○ (Good): Scratches are less than 15% of the total square area × (Poor): Damage to 15% or more of the total square area

[0121] [Table 1]

[0122] The results in Table 1 show that the laminates having the copper foil layer / resin layer / copper foil layer laminate structure of the examples of the present invention were excellent in the evaluations of film properties, weight, resistance value and adhesion. [Industrial Applicability]

[0123] The laminate of the present invention has an excellent resin layer film property (good film formation), is lightweight, has a low resistance value (excellent electrical conductivity), and has high adhesion between the resin layer and the metal foil layer, and can therefore be suitably used as a current collecting layer, particularly as a current collecting layer for the negative electrode of a battery.

Claims

1. The following components (A) to (C) and (E): (A) an epoxy resin as a thermosetting resin; (B) a phenoxy resin as a thermoplastic resin; (C) a curing agent; and (E) Carbon black as a conductive filler and metal foil layers formed on both sides of the resin layer, wherein the resin layer has a thickness of 3 to 60 μm.

2. The laminate according to claim 1 , wherein the resin composition further comprises (D) a curing accelerator.

3. 2. The laminate of claim 1, wherein the metal foil layer is a copper foil layer.

4. A method for producing the laminate according to claim 1, comprising the steps of: (1) a step of disposing a metal foil having a carrier on one side on both sides of a resin composition layer made of a resin composition such that the other side of the metal foil is in contact with the other side of the resin composition layer; (2) a step of thermally curing the resin composition layer; and (3) A step of peeling off the carrier from the metal foils on both sides of the resin composition layer after thermal curing. A manufacturing method comprising:

5. The method according to claim 4, wherein the step (1) comprises: (1a-1) applying a varnish of a resin composition to one surface of a metal foil having a carrier on the other surface thereof, and drying the varnish to form a resin composition layer; and (1a-2) laminating a metal foil having a carrier on one surface thereof so that the other surface of the metal foil is in contact with the resin composition layer.

6. The method according to claim 4, wherein the step (1) comprises: (1b-1-1) applying a varnish of a resin composition to one side of a support and drying the varnish to form a resin composition layer; (1b-1-2) laminating a metal foil having a carrier on one side to the resin composition layer so that the other side of the metal foil contacts the resin composition layer; and (1b-1-3) peeling the support and laminating a metal foil having a carrier on one side to the exposed resin composition layer so that the other side of the metal foil contacts the resin composition layer.

7. The method according to claim 4, wherein the step (1) comprises: (1b-2-1) applying a varnish of a resin composition to one side of a support and drying the varnish to form a resin composition layer; and (1b-2-2) peeling the support and laminating a metal foil having a carrier on one side to both sides of the resin composition layer so that the other side of the metal foil is in contact with the other side of the metal foil.

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