Adhesive composition, two-liquid type adhesive composition, and laminate

Abstract

An adhesive composition comprising an acid-modified polyolefin and an epoxy resin, the aforementioned acid-modified polyolefin satisfying conditions (i) to (iii) below, condition (i): being an acid-modified product of a homopolymer of butene or an acid-modified product of a copolymer of butene, condition (ii): having an acid value of 0.1 mg KOH / g to 15 mg KOH / g, and condition (iii): having a weight average molecular weight of 80,000 or more, the aforementioned epoxy resin having at least one structure selected from the group consisting of a dicyclopentadiene structure, a cresol structure, a naphthalene structure, and a constituting unit derived from butadiene, and the content of the aforementioned epoxy resin being 2 mass parts to 40 mass parts relative to 100 mass parts of the aforementioned acid-modified polyolefin.

Description

Technical Field

[0001] This disclosure relates to adhesive compositions, two-component adhesive compositions, and laminates. Background Technology

[0002] Adhesive compositions are used in industrial products such as electronic devices and batteries to bond metal materials such as aluminum and copper. Furthermore, in battery applications, long-term chemical resistance is required. Adhesive compositions utilizing acid-modified polyolefins are known as materials that satisfy both adhesion to metals and chemical resistance.

[0003] For example, Patent Document 1 discloses that the composition of acid-modified polyolefins with high acid values ​​exhibits high chemical resistance.

[0004] Furthermore, Patent Document 2 or 3 discloses a method that uses an acid-modified polyolefin with a low acid value to exhibit high chemical resistance relative to 100 parts of acid-modified polyolefin combined with less than 2 parts of epoxy resin. Existing technical documents Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2020-169250 Patent Document 2: International Publication No. 2017 / 126520 Patent Document 3: International Publication No. 2021 / 131722 Summary of the Invention The problem the invention aims to solve

[0006] In recent years, such adhesives have required long-term chemical resistance, but while the adhesive compositions described in Patent Documents 1-3 can provide short-term chemical resistance, they are difficult to maintain performance over the long term.

[0007] The technical problem to be solved by this disclosure is to provide an adhesive composition with excellent long-term chemical resistance after curing. Another technical problem to be solved by this disclosure is to provide a two-component adhesive composition with excellent long-term chemical resistance after curing. Another technical problem to be solved by this disclosure is to provide a laminate using the aforementioned adhesive composition or the aforementioned two-component adhesive composition. Technical means to solve the problem

[0008] The specific measures adopted to solve the above-mentioned technical problems include the following solutions. <1> An adhesive composition comprising an acid-modified polyolefin and an epoxy resin, wherein the acid-modified polyolefin satisfies the following conditions (i)-(iii). Condition (i): It is an acid-modified homopolymer of butene or an acid-modified copolymer of butene. Condition (ii): Acid value of 0.1 mg KOH / g - 15 mg KOH / g Condition (iii): Weight-average molecular weight is above 80,000. The aforementioned epoxy resin has at least one structure selected from the group consisting of dicyclopentadiene, cresol, naphthalene, and butadiene-derived building blocks. The content of the aforementioned epoxy resin is 2 to 40 parts by mass relative to 100 parts by mass of the aforementioned acid-modified polyolefin. <2> according to <1> The adhesive composition wherein the aforementioned acid-modified polyolefin is a maleic anhydride-modified polyolefin. <3> according to <1> or <2> The adhesive composition wherein the aforementioned acid-modified polyolefin is an acid-modified copolymer of propylene and 1-butene. <4> according to <1> - <3> The adhesive composition according to any one of the following methods, wherein the acid value of the aforementioned acid-modified polyolefin is 1 mg KOH / g-10 mg KOH / g. <5> according to <1> - <4> The adhesive composition according to any one of the following methods, wherein the weight-average molecular weight of the aforementioned acid-modified polyolefin is 90,000-200,000. <6> according to <1> - <5> The adhesive composition described in any one of the above statements further comprises a curing accelerator, wherein the curing accelerator comprises an imidazole compound. <7> according to <1> - <6> The adhesive composition described in any one of the above statements further comprises aromatic solvents, alicyclic solvents, and ketone solvents. <8> according to <1> - <7> The adhesive composition described in any one of the following is an adhesive composition for use between metallic materials. <9> A two-component adhesive composition comprising a first reagent and a second reagent, The first reagent contains acid-modified polyolefin and epoxy resin. The aforementioned acid-modified polyolefins satisfy the following conditions (i)-(iii), Condition (i): It is an acid-modified homopolymer of butene or an acid-modified copolymer of butene. Condition (ii): Acid value of 0.1 mg KOH / g - 15 mg KOH / g Condition (iii): Weight-average molecular weight is 80,000-300,000. The aforementioned epoxy resin has at least one structure selected from the group consisting of dicyclopentadiene, cresol, naphthalene, and butadiene-derived building blocks. The content of the aforementioned epoxy resin is 2 to 40 parts by weight relative to 100 parts by weight of the aforementioned acid-modified polyolefin. The second reagent contains a curing accelerator. <10> according to <9> The two-component adhesive composition wherein the aforementioned acid-modified polyolefin is a maleic anhydride-modified polyolefin. <11> according to <9> or <10> The two-component adhesive composition wherein the aforementioned acid-modified polyolefin is an acid-modified copolymer of propylene and 1-butene. <12> according to <9> - <11> The two-component adhesive composition according to any one of the following methods, wherein the acid value of the aforementioned acid-modified polyolefin is 1 mg KOH / g-10 mg KOH / g. <13> according to <9> - <12> The two-component adhesive composition according to any one of the following methods, wherein the weight-average molecular weight of the aforementioned acid-modified polyolefin is 90,000-200,000. <14> according to <9> - <13> The two-component adhesive composition according to any one of the above, wherein the aforementioned curing accelerator comprises an imidazole compound. <15> according to <9> - <14> The two-component adhesive composition according to any one of the above-mentioned first reagents further comprises aromatic solvents, alicyclic solvents, and ketone solvents. <16> according to <9> - <15> The two-component adhesive composition described in any one of the following is a two-component adhesive composition for use between metallic materials. <17> A laminated body, which is formed by bonding a first metal material and a second metal material together with an adhesive, wherein the adhesive is... <1> - <8> The adhesive composition described in any one of the following statements or <9> - <16> The two-component adhesive composition described in any one of the following statements. Invention Effects

[0009] According to this disclosure, an adhesive composition with excellent long-term chemical resistance after curing is provided. According to this disclosure, a two-component adhesive composition with excellent long-term chemical resistance after curing is provided. Furthermore, according to this disclosure, a laminate using the aforementioned adhesive composition or the aforementioned two-component adhesive composition is provided. Detailed Implementation

[0010] The following describes an embodiment as an example of this disclosure. These descriptions and examples are illustrative and do not limit the scope of the embodiments. In this disclosure, the range of values ​​represented by "-" refers to the range that includes the values ​​recorded before and after "-" as the minimum and maximum values, respectively. In the numerical ranges described in this disclosure, the upper or lower limit value recorded in one numerical range can be replaced with the upper or lower limit value of the numerical range recorded in other segments. In the numerical range described in this disclosure, the upper or lower limit of the numerical range may be replaced with the values ​​shown in the embodiments. In this disclosure, the term "process" includes not only independent processes, but also processes that cannot be clearly distinguished from other processes, as long as they achieve the purpose of the process. When describing embodiments in this disclosure with reference to the accompanying drawings, the configuration of the embodiments is not limited to the configuration shown in the drawings. Furthermore, the sizes of the components in the drawings are conceptual, and the relative sizes of the components are not limited thereto. In this disclosure, each component may contain multiple corresponding substances. When referring to the amount of each component in the composition in this disclosure, if multiple substances belonging to each component are present in the composition, unless otherwise specified, it refers to the total amount of such multiple substances present in the composition. In this disclosure, "(meth)acrylic acid" is an expression that includes either acrylic acid or methacrylic acid, and "(meth)acrylate" is an expression that includes either acrylate or methacrylate.

[0011] (Adhesive composition) The adhesive composition disclosed herein comprises an acid-modified polyolefin and an epoxy resin, wherein the acid-modified polyolefin satisfies the following conditions (i)-(iii), and the epoxy resin has at least one structure selected from the group consisting of dicyclopentadiene, cresol, naphthalene, and butadiene-derived constituent units, and the content of the epoxy resin is 2 to 40 parts by mass relative to 100 parts by mass of the acid-modified polyolefin. Condition (i): It is an acid-modified homopolymer of polybutene or an acid-modified copolymer of butene. Condition (ii): Acid value of 0.1 mg KOH / g - 15 mg KOH / g Condition (iii): Weight-average molecular weight is above 80,000

[0012] As described above, as in Patent Documents 1-3, existing adhesive compositions, while capable of providing short-term chemical resistance, are difficult to maintain long-term performance. The inventors conducted a detailed study and concluded that the adhesive comprises an acid-modified polyolefin and an epoxy resin. The acid-modified polyolefin satisfies the aforementioned conditions (i)-(iii), and the epoxy resin has at least one structure selected from the group consisting of dicyclopentadiene, cresol, naphthalene, and butadiene-derived constituent units. The content of the epoxy resin is 2 to 40 parts by mass relative to 100 parts by mass of the acid-modified polyolefin. As a result, the cured adhesive composition exhibits high crystallinity and high crosslinking density, and excellent long-term chemical resistance after curing.

[0013] The adhesive composition of this disclosure is described in detail below.

[0014] <Acid-modified polyolefins> The adhesive composition disclosed herein comprises an acid-modified polyolefin that satisfies the following conditions (i)-(iii). Condition (i): It is an acid-modified homopolymer of butene or an acid-modified copolymer of butene. Condition (ii): Acid value of 0.1 mg KOH / g-15 mg KOH / g. Condition (iii): Weight-average molecular weight is above 80,000. Acid-modified polyolefins are polyolefins that have been modified by imparting acid groups to polyolefins (hereinafter also referred to as "unmodified polyolefins"). Specifically, acid-modified polyolefins are obtained by modifying unmodified polyolefins with monomers containing acid groups.

[0015] Specific examples of unmodified polyolefins include homopolymers or copolymers of butene. From the viewpoint of long-term chemical resistance after curing (hereinafter also referred to as "chemical resistance"), copolymers of butene are preferred, copolymers of 1-butene are more preferred, and copolymers of propylene and 1-butene are particularly preferred. Furthermore, copolymers of butene can be random copolymers or block copolymers. Butene used as a homopolymer or copolymer of butene can include 1-butene and isobutene, with 1-butene being a preferred example. Monomers other than butene used in copolymers of butene include ethylene, propylene, and α-olefins other than 1-butene and isobutene. Here, α-olefins other than 1-butene include 1-hexene and 1-octene.

[0016] Among the acid-containing monomers used to modify unmodified polyolefins, examples of acid groups include carboxylic acid groups, carboxylic anhydride groups, sulfonic acid groups, and phosphate groups. From the perspective of ease of modification, carboxylic acid groups and carboxylic anhydride groups are preferred, and carboxylic anhydride groups are particularly preferred. The carboxylic acid monomers used in the acid-containing monomers described below may also be carboxylic acid monomers that form carboxylic anhydride groups with the same or other carboxylic acid monomers, including carboxylic anhydride monomers. Unsaturated dicarboxylic acid compounds are particularly preferred to have carboxylic acid groups condensed to form carboxylic anhydride groups.

[0017] As monomers containing carboxylic acid groups (or carboxylic anhydride groups), these are compounds that have olefinic double bonds and carboxylic acid groups within the same molecule. Examples include various unsaturated monocarboxylic acid compounds, unsaturated dicarboxylic acid compounds, and unsaturated tricarboxylic acid compounds. Specific examples of unsaturated monocarboxylic acid compounds include acrylic acid, methacrylic acid, crotonic acid, and isocrotonic acid. Examples of unsaturated dicarboxylic acid compounds include maleic acid, itaconic acid, citraconic acid, tetrahydrophthalic acid, nadic acid, and norbornyl edodelic acid. Examples of unsaturated tricarboxylic acid compounds include aconitic acid. From the perspective of easy modification and excellent adhesion, unsaturated dicarboxylic acid compounds and unsaturated tricarboxylic acid compounds are preferred as acidic monomers, with itaconic acid, maleic acid and aconitic acid being particularly preferred. Acid-containing monomers can be used alone or in combination of two or more.

[0018] Among them, maleic acid or maleic anhydride are preferred due to their high modification effect, with maleic anhydride being particularly preferred. That is, maleic anhydride-modified polyolefins are preferred as acid-modified polyolefins.

[0019] Acid-modified polyolefins can be co-modified with an acid-containing monomer and an alkyl methacrylate (e.g., graft modification). As an alkyl methacrylate, an esterification of an alkyl alcohol with 8-18 carbon atoms and (meth)acrylic acid is preferred.

[0020] As a method for graft modification, well-known methods can be employed. For example, a method in which an acid compound is grafted onto a polyolefin in a molten or solution state in the presence of a free radical polymerization initiator such as an organic peroxide or an aliphatic azo compound.

[0021] The grafting reaction temperature is preferably 80°C-160°C when the reaction is in solution and 150°C-300°C when the reaction is in molten state. In both solution and molten states, the reaction rate increases above the lower limit of the above-mentioned reaction temperature range, while the decrease in the molecular weight of the resin can be suppressed and the mechanical strength of the obtained acid-modified polyolefin can be maintained below the upper limit of the above-mentioned reaction temperature range.

[0022] The free radical polymerization initiator used can be selected from commercially available organic peroxides, taking into account factors such as reaction temperature.

[0023] To prevent unreacted acid compounds from negatively impacting adhesive strength during grafting modification, it is preferable to remove unreacted acid compounds using known methods such as vacuum distillation.

[0024] It should be noted that the acid value can be used as a reference amount for the amount of functional groups introduced into the acid-modified polyolefin. The acid value of the acid-modified polyolefin is 0.1 mg KOH / g-15.0 mg KOH / g, and from the viewpoint of adhesion and chemical resistance, it is preferably 0.5 mg KOH / g-12.5 mg KOH / g, and more preferably 1 mg KOH / g-10 mg KOH / g. If the acid value of the acid-modified polyolefin is lower than 0.1 mg KOH / g, the adhesion is insufficient; if it exceeds 15.0 mg KOH / g, the crystallinity of the resin decreases due to modification, and the chemical resistance decreases.

[0025] From the viewpoint of heat resistance, the melting point of acid-modified polyolefins is preferably 50°C-120°C, more preferably 70°C-110°C, and even more preferably 80°C-95°C. Within these ranges, chemical resistance is superior, and solubility in solvents is also excellent.

[0026] The weight-average molecular weight (Mw) of the acid-modified polyolefin is 80,000 or more, preferably 90,000-300,000, more preferably 90,000-200,000, and particularly preferably 130,000-200,000. Within these ranges, it exhibits superior chemical resistance and excellent solubility in solvents. The weight-average molecular weight (Mw) of acid-modified polyolefins is the value of polystyrene converted from the molecular weight determined by gel permeation chromatography.

[0027] From the viewpoint of improving adhesion, the propylene unit in the acid-modified polyolefin is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more.

[0028] Acid-modified polyolefins can be used alone or in combination of two or more. From the viewpoint of chemical resistance, the content of acid-modified polyolefin is preferably 60%-98% by mass, more preferably 70%-97% by mass, and particularly preferably 80%-97% by mass, relative to all components of the adhesive composition other than the solvent (total solids of the adhesive composition).

[0029] As an acid-modified polyolefin, commercially available products can also be used. Examples of commercially available products include "Modic" manufactured by Mitsubishi Chemical Corporation, "ADMER" and "UniStol" manufactured by Mitsui Chemicals Co., Ltd., "TOYO-TAC" manufactured by Toyobo Co., Ltd., and "UMEX" manufactured by Sanyo Chemical Co., Ltd.

[0030] <Epoxy Resin> The adhesive composition disclosed herein comprises an epoxy resin having at least one structure selected from the group consisting of bridged aliphatic hydrocarbon structures, aromatic ring structures having hydroxyl and alkyl groups, polycyclic aromatic hydrocarbon structures, and butadiene-derived constituent units. Examples of bridged cyclic aliphatic hydrocarbon structures include dicyclopentadiene, norbornene, and adamantane. Examples of aromatic ring structures containing hydroxyl and alkyl groups include cresol and xylenol. Examples of polycyclic aromatic hydrocarbon structures include naphthalene, anthracene, phenanthrene, and pyrene. From the viewpoint of chemical resistance, the epoxy resin used in this disclosure preferably has at least one structure selected from the group consisting of bridged aliphatic hydrocarbon structures, aromatic ring structures having hydroxyl and alkyl groups, and polycyclic aromatic hydrocarbon structures; more preferably, it has at least one structure selected from the group consisting of bridged aliphatic hydrocarbon structures and aromatic ring structures having hydroxyl and alkyl groups; and particularly preferably, it has a bridged aliphatic hydrocarbon structure.

[0031] Examples of epoxy resins having the aforementioned structure include epoxy resins containing a dicyclopentadiene backbone, cresol phenolic epoxy resins, epoxy resins containing a naphthalene structure, and epoxidized polybutadiene. From the viewpoint of chemical resistance, the epoxy resin used in this disclosure preferably has at least one structure selected from the group consisting of dicyclopentadiene, cresol, naphthalene and butadiene-derived building blocks, more preferably has at least one structure selected from the group consisting of dicyclopentadiene, cresol and naphthalene, even more preferably has at least one structure selected from the group consisting of dicyclopentadiene and cresol, and particularly preferably has a dicyclopentadiene structure.

[0032] As an epoxy resin, compounds having two or more epoxy groups per molecule are preferred. This is because the formation of a cross-linked structure through reaction with acid-modified polyolefins exhibits high adhesion and chemical resistance. Furthermore, when using epoxy resins with two or more epoxy groups, the degree of cross-linking with acid-modified polyolefins is sufficient, resulting in adequate chemical resistance.

[0033] From the viewpoint of adhesion and chemical resistance, the epoxy equivalent of the epoxy resin is preferably 50 g / eq-400 g / eq, more preferably 100 g / eq-350 g / eq, and particularly preferably 200 g / eq-300 g / eq. The epoxy equivalent of the epoxy resin disclosed herein is defined as the mass of epoxy resin containing 1 equivalent of epoxy groups, which refers to the measurement value obtained based on JIS K 7236:2001.

[0034] Epoxy resin can be used alone or in combination with two or more types. The epoxy resin content is 2 to 40 parts by weight relative to 100 parts by weight of acid-modified polyolefin. From the viewpoint of adhesion and chemical resistance, 2 to 30 parts by weight is preferred, more preferably 3 to 20 parts by weight, and particularly preferably 4 to 10 parts by weight. If the epoxy resin content is less than 2 parts by weight or more than 40 parts by weight, the chemical resistance decreases.

[0035] <Curing Accelerator> From the viewpoint of curability and curing speed, the adhesive composition disclosed herein preferably contains a curing accelerator. From the viewpoint of curability and curing speed, as a curing accelerator, it is preferable to include at least one compound selected from the group consisting of imidazole compounds, amine compounds and phosphorus compounds, and more preferably imidazole compounds. Curing accelerators can be catalysts added from the viewpoint of promoting the reaction of the aforementioned curing agents.

[0036] Examples of imidazole compounds include 2-methylimidazolium, 2-undecylimidazolium, 2-heptadecylimidazolium, 1,2-dimethylimidazolium, 2-methyl-4-ethylimidazolium, 2-phenylimidazolium, 2-phenyl-4-methylimidazolium, 1-benzyl-2-methylimidazolium, 1-benzyl-2-phenylimidazolium, 2,4-diamino-6-[2'-methylimidazolyl-(1')]ethyl-s-triazine, and 2,4-diamino-6-[2'- Undecylimidazolyl-(1')]ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]ethyl-s-triazine, 2,4-diamino-6-[2'-methylimidazolyl-(1')]ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazolyl isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazolium, 2-phenyl-4-methyl-5-hydroxymethylimidazolium, etc.

[0037] Examples of amine compounds include benzyl dimethylamine, 2-(dimethylaminomethyl)phenol, 2,4,6-tris(dimethylaminomethyl)phenol, tetramethylguanidine, triethanolamine, N,N'-dimethylpiperazine, triethylenediamine, and 1,8-diazabicyclo[5.4.0]undecene, among other tertiary amines. In addition, examples of amine compounds include, for instance, formate, octanoate, p-toluenesulfonate, phthalate, phenolate, or phenolic resin salts of 1,8-diazabicyclo[5.4.0]undecene; and tertiary amine salts such as formate, octanoate, p-toluenesulfonate, phthalate, phenolate, or phenolic resin salts of 1,5-diazabicyclo[4.3.0]nonene.

[0038] Examples of phosphorus compounds include triphenylphosphine, tributylphosphine, methyldiphenylphosphine, tris(4-methylphenyl)phosphine, tris(4-butylphenyl)phosphine, diphenylphosphine, and phenylphosphine.

[0039] The content of curing accelerator can be appropriately determined based on the type and amount of acid-modified polyolefin, the type and amount of curing accelerator, etc. One type of curing accelerator may be used, or two or more may be used. From the viewpoint of curability and curing speed, the content of curing accelerator is preferably 0.01-2 parts by mass, more preferably 0.02-1.5 parts by mass, and particularly preferably 0.05-1 parts by mass, relative to 100 parts by mass of acid-modified polyolefin.

[0040] <Other Polymers> The adhesive composition disclosed herein may include polymers other than the aforementioned acid-modified polyolefins and high molecular weight epoxy resins for purposes such as adhesion, hydrolysis resistance, and heat resistance. When the adhesive composition includes other polymers, there may be one or more of these other polymers.

[0041] Other polymers that can be listed include, for example, phenolic resins, urea-formaldehyde resins, melamine resins, benzoguanamine resins, alkyd resins, unsaturated polyester resins, vinyl ester resins, diallyl terephthalate resins, silicone resins, polyurethane resins, furan resins, ketone resins, xylene resins, thermosetting polyimide resins, benzoxazine resins, reactive ester resins, aniline resins, cyanate ester resins, styrene-maleic anhydride (SMA) resins, polyethylene resins, polypropylene resins, polystyrene resins, rubber-modified polystyrene resins, acrylonitrile-butadiene-styrene (ABS) resins, acrylonitrile-styrene (AS) resins, polymethyl methacrylate resins, acrylic resins, polyvinylidene chloride resins, polyvinylidene chloride resins, polyethylene terephthalate resins, ethylene-vinyl alcohol resins, and acetic acid. Cellulose resins, ionomer resins, polyacrylonitrile resins, polyamide resins, polyacetal resins, polybutylene terephthalate resins, polylactic acid resins, polyphenylene ether resins, modified polyphenylene ether resins, polycarbonate resins, polysulfone resins, polyphenylene sulfide resins, polyetherimide resins, polyethersulfone resins, polyarylate resins, thermoplastic polyimide resins, polyamide-imide resins, polyetheretherketone resins, polyketide resins, liquid crystal polyester resins, fluoropolymers, syndiotactic polystyrene resins, cyclic polyolefin resins, α-olefin copolymers, acrylic elastomers, polyisoprene, hydrogenated polyisoprene, polybutadiene, cyclic olefin polymers, cyclic olefin copolymers, polyamines, polyamides, melamine resins, urea-formaldehyde resins, styrene-based thermoplastic resins, hydroxyl-modified polyolefin resins, glycidyl methacrylate-modified polyolefin resins, etc.

[0042] Other polymers may be used in single or multiple ways. The content of other polymers is preferably less than that of acid-modified polyolefins, and more preferably less than that of epoxy resins.

[0043] <Additives> In addition to the foregoing, the adhesive compositions disclosed herein may also contain additives. As an additive, known additives may be used, preferably at least one additive selected from the group consisting of antioxidants, ultraviolet absorbers, fillers, reinforcing fibers, release agents, processing aids, flame retardants, plasticizers, nucleating agents, antistatic agents, pigments, dyes, foaming agents, and combinations thereof.

[0044] Solvent From the viewpoints of stability over time, coatability, and workability, the adhesive composition disclosed herein preferably also contains a solvent. Solvents suitable for the adhesive compositions of this disclosure include well-known solvents. Specific examples of solvents include aromatic solvents such as toluene and xylene; aliphatic solvents such as n-hexane; alicyclic solvents such as cyclohexane, methylcyclohexane, and ethylcyclohexane; ketone solvents such as acetone and methyl ethyl ketone; alcohol solvents such as methanol and ethanol; ester solvents such as ethyl acetate and butyl acetate; and propylene glycol ether solvents such as propylene glycol methyl ether, propylene glycol ethyl ether, and propylene glycol tert-butyl ether. These solvents can be used in single-use or in combination of two or more.

[0045] From the viewpoint of suppressing solidification and suppressing thickening over time, the solvent preferably includes at least one solvent A selected from aromatic solvents, aliphatic solvents, ketone solvents, and alcohol solvents, and more preferably includes aromatic solvents, alicyclic solvents, and ketone solvents.

[0046] -Aromatic solvents- Aromatic solvents are solvents that contain an aromatic ring within a molecule. Examples of aromatic solvents include toluene, o-xylene, m-xylene, p-xylene, anisole, ethyl benzyl ether, tolyl methyl ether, diphenyl ether, dibenzyl ether, phenethyl ether, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, isopropyltoluene, and mesitylene. Among them, from the viewpoint of suppressing solidification and suppressing thickening over time, aromatic solvents with low substituent number of carbon atoms (especially toluene) with 6-8 carbon atoms are preferred.

[0047] Ketone solvents are solvents that contain a ketone group within a molecule. Examples of ketone solvents include methyl ethyl ketone, acetone, diethyl ketone, methyl isobutyl ketone, methyl n-pentyl ketone, methyl isopentyl ketone, and 2-heptanone.

[0048] Alcohol solvents are solvents that contain an alcohol hydroxyl group in one molecule. As alcohols, for example as alcohol solvents, examples include methanol, ethanol, isopropanol, n-propanol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, etc.

[0049] Among them, from the viewpoint of suppressing solidification and suppressing thickening over time, lower alkyl ketones (especially methyl ethyl ketone) with 3-5 carbon atoms are preferred as ketone solvents, and lower alcohols with 1-4 carbon atoms (especially isopropanol) are preferred as alcohol solvents.

[0050] -Aliphatic solvents- Aliphatic solvents are solvents that contain an aliphatic group within a molecule. Examples of aliphatic solvents include n-heptane, n-hexane, octane, nonane, decane, undecane, dodecane, isododecane; cyclohexane, methylcyclohexane, ethylcyclohexane, dimethylcyclohexane, and other alicyclic solvents; and paraffin solvents. Among them, from the viewpoint of suppressing solidification and thickening over time, aliphatic solvents (especially methylcyclohexane) are preferred as aliphatic solvents.

[0051] - Solvent composition ratio- From the viewpoint of suppressing solidification and suppressing thickening over time, the preferred amounts of each solvent are as follows, when the total amount of solvent is 100 parts by mass. The amount of aromatic solvent is preferably 10 to 45 parts by mass, more preferably 10 to 30 parts by mass, and particularly preferably 10 to 20 parts by mass. The amount of at least one solvent selected from the group consisting of ketone solvents and alcohol solvents is preferably 5 to 20 parts by mass, more preferably 8 to 20 parts by mass, and particularly preferably 10 to 20 parts by mass. The amount of aliphatic solvent is preferably 45-70 parts by mass, more preferably 55-70 parts by mass, and particularly preferably 60-70 parts by mass.

[0052] From the viewpoint of suppressing solidification and suppressing thickening over time, the ratio of aromatic solvent to aliphatic solvent is preferably 15%-25% by mass, more preferably 15%-23% by mass, and even more preferably 15%-20% by mass. From the viewpoint of suppressing solidification and suppressing thickening over time, the ratio of at least one solvent selected from the group consisting of ketone solvents and alcohol solvents is preferably 5%-35% by mass, more preferably 10%-35% by mass, and even more preferably 15%-35% by mass.

[0053] Solvents can include solvents other than aromatic solvents, ketone solvents, alcohol solvents, and aliphatic solvents. The proportion of aromatic solvents, ketone solvents, alcohol solvents and aliphatic solvents in the solvent is preferably 90% by mass or more, more preferably 95% by mass or more. It should be noted that the proportion of aromatic solvents, ketone solvents, alcohol solvents, and aliphatic solvents in the solvent is preferably 100 by mass.

[0054] The solvent content is preferably 75%-95% by mass, more preferably 80%-90% by mass, relative to the total mass of the adhesive composition.

[0055] <Applications> The adhesive composition disclosed herein exhibits excellent long-term chemical resistance after curing, making it suitable for use in electronic devices and batteries. Due to the aforementioned chemical resistance, it also exhibits excellent electrolyte resistance, making it particularly suitable for battery applications. Furthermore, the adhesive composition disclosed herein exhibits excellent adhesion between metallic materials, making it suitable for applications involving the bonding of metallic materials. The metal materials being bonded can be of the same type or different types. Furthermore, the adhesive composition disclosed herein, due to having the aforementioned properties, can be used as an adhesive for automobiles, vehicles (Shinkansen, trams), ships, aircraft, construction, civil engineering, electronics, aerospace industries, and other industrial products.

[0056] (Two-component adhesive composition) The two-component adhesive composition disclosed herein comprises a first reagent and a second reagent. The first reagent comprises an acid-modified polyolefin and an epoxy resin. The acid-modified polyolefin satisfies the following conditions (i)-(iii). The epoxy resin has at least one structure selected from the group consisting of dicyclopentadiene, cresol, naphthalene, and butadiene-derived constituent units. The content of the epoxy resin is 2 to 40 parts by mass relative to 100 parts by mass of the acid-modified polyolefin. The second reagent comprises a curing accelerator. Condition (i): It is an acid-modified homopolymer of butene or an acid-modified copolymer of butene. Condition (ii): Acid value of 0.1 mg KOH / g-15 mg KOH / g. Condition (iii): Weight-average molecular weight is above 80,000.

[0057] Except as described below, the preferred embodiments of the first reagent in the two-component adhesive composition of this disclosure are the same as the preferred embodiments of the adhesive composition of this disclosure described above. Preferably, the first reagent mentioned above does not contain a curing accelerator.

[0058] Except as described below, the preferred form of the curing accelerator of the second reagent in the two-component adhesive composition of this disclosure is the same as the preferred form of the curing accelerator in the adhesive composition of this disclosure described above. The content of the curing accelerator in the aforementioned second reagent is not particularly limited. From the viewpoint of curability and curing speed, it is preferably 0.1%-20% by mass, more preferably 1%-10% by mass, and particularly preferably 2.5%-5% by mass relative to the total mass of the aforementioned second reagent.

[0059] As the solvent contained in the aforementioned second reagent, from the viewpoint of the solubility of the curing accelerator and its stability over time, it is preferable to include at least one solvent A selected from ketone solvents and alcohol solvents, and more preferably, it includes both ketone solvents and alcohol solvents. Furthermore, from the viewpoint of the solubility of the curing accelerator and its stability over time, it is particularly preferable that the solvent contained in the aforementioned second reagent is an alcohol solvent, which contains more solvent than ketone solvents. From the viewpoint of the solubility and stability over time of the curing accelerator, the amount of ketone solvent relative to the total mass of the aforementioned second reagent is preferably 10%-50% by mass, more preferably 20%-45% by mass, and particularly preferably 30-40 parts by mass. From the viewpoint of the solubility and stability over time of the curing accelerator, the amount of alcohol solvent is preferably 30%-90% by mass, more preferably 40%-75% by mass, and particularly preferably 50%-65% by mass.

[0060] The solvents contained in the aforementioned second reagent may also include solvents other than ketone solvents, alcohol solvents and aliphatic solvents. The proportion of ketone solvents and alcohol solvents in the solvent is preferably 90% by mass or more, and more preferably 95% by mass or more. It should be noted that the proportion of ketone solvents and alcohol solvents in the solvent is preferably 100 by mass.

[0061] The solvent content in the aforementioned second reagent is preferably 80%-99.9% by mass, more preferably 90%-99% by mass, relative to the total mass of the second reagent.

[0062] (Layered structure) The laminate disclosed herein is a laminate formed by bonding a first metal material and a second metal material together with an adhesive, wherein the adhesive is the adhesive composition of the present disclosure or the two-component adhesive composition of the present disclosure.

[0063] <Metallic Materials> The metals constituting the first and second metallic materials can be selected from one or more of the following: copper, stainless steel, brass, silver, aluminum, and nickel. The first and second metal materials can be of the same type or different types. For the first and second metal materials, in order to achieve good adhesion, the surface of the metal substrate can be roughened or the residual oil on the surface of the metal substrate can be removed.

[0064] There are no particular restrictions on the shape of the first and second metal materials, as long as they are the desired shapes. For example, when the first metal material and the second metal material are plate-shaped metal substrates, the thickness of the metal substrate is preferably 1 μm or more and 200 μm or less, more preferably 3 μm or more and 100 μm or less, and even more preferably 6 μm or more and 50 μm or less. By setting the thickness to 1 μm or more, it is easy to achieve good strength in the connector. Furthermore, by setting the thickness to 1 μm or more, the metal substrate can be given the specified strength, and substrate breakage under stress can be easily suppressed.

[0065] The adhesive composition is preferably formed on a first metal material and / or a second metal material by a coating method. For example, the adhesive composition can be applied to the first metal material by a coating method, the solvent can be evaporated to form a coated metal material, the resulting coated metal material can be bonded to the second metal material, and then the coating can be cured to form an adhesive layer. When using a two-component adhesive composition, for example, a first reagent can be applied to a first metal material by a coating method, the solvent evaporates, and a first metal material with a coating film is formed. A second reagent can be applied to a second metal material by a coating method, the solvent evaporates, and a second metal material with a coating film is formed. The resulting first metal material with a coating film is bonded to the second metal material with a coating film, and then the coating film is cured, thereby forming an adhesive layer. Alternatively, for example, the first reagent and the second reagent can be mixed first, and the mixture of the first reagent and the second reagent can be coated onto the first metal material using a coating method. The solvent is then evaporated to form a coated metal material. The resulting coated metal material is then bonded to the second metal material, and the coating is then cured to form an adhesive layer.

[0066] Examples of coating methods for adhesive compositions or two-component adhesive compositions include bar coaters, spray guns, dispensers, roller coaters, curtain coaters, and dip coaters.

[0067] The temperature and time for solvent evaporation can be appropriately set considering factors such as the type of solvent; for example, they can be set to 50°C-200°C and 0.1 minutes-5 minutes.

[0068] The laminates disclosed herein can be manufactured, for example, as described below. First, a coated metal material and a second metal material are prepared by coating the adhesive composition disclosed herein. Next, the coated surface of the metal material is placed opposite the second metal material, and a hot lamination process is performed to obtain a multilayered laminate. Next, the laminate is cured to allow the coating to harden.

[0069] Thermal lamination can be performed using a known laminator. There are no special restrictions on lamination conditions; general conditions can be applied. The lamination temperature is preferably 50°C-200°C, more preferably 80°C-150°C. The preferred conveying speed during lamination is 0.01 m / min to 200 m / min, and more preferably 0.1 m / min to 100 m / min. The lamination pressure is preferably 0.01 MPa-10 MPa, more preferably 0.1 MPa-5 MPa.

[0070] Through the curing and heat-lamination of the laminate, the coating film is cured, resulting in a laminate with a stronger bond between the first metal material and the adhesive layer and the second metal material. As a curing condition, the laminate can be left to stand for 0.5 to 7 days at a temperature of 40°C to 150°C. Example

[0071] The following examples illustrate the present disclosure in more detail. However, the present disclosure is not limited to the following examples.

[0072] <Method for determining the acid value of acid-modified polyolefins> Approximately 10 g of the acid-modified polyolefin was accurately measured and placed into a 200 mL tall beaker. 150 mL of a 1:1 (volume ratio) mixture of xylene and dimethylformamide was added as the titration solvent. Titration was performed using a 1 w / v phenolphthalein ethanol solution (manufactured by FUJIFILM Wako Pure Chemical Corporation) as an indicator, and the acid value was determined from the titration volume. Specifically, the acid value was calculated according to the following formula. It should be noted that, in this invention, the aforementioned acid value is the average value obtained from three repeated titrations. Acid value (mg KOH / g) = (EP1 - BL1) × FA1 × C1 / SIZE In the above formula, “EP1” represents the titration amount (mL), “BL1” represents the blank value (mL), “FA1” represents the coefficient of the titrant (1.00), “C1” represents the concentration conversion value (5.611 mg / m), and “SIZE” represents the sampling amount of acid-modified polyolefin (g).

[0073] <Methods for determining the melting point of acid-modified polyolefins> The value was measured using a differential scanning calorimeter (TA Instruments Japan, Q-2000) at a rate of 20°C / min to melt the material, and after cooling and resinification, the temperature was measured from the peak temperature of the melt peak when the material was reheated and melted.

[0074] <Adhesive Composition Materials> 1. Acid-modified polyolefins • Acid-modified polyolefin-1 (PO-1) Propylene-butene-1 copolymer, melting point 80°C, molecular weight Mw 97000, acid value 13 mg KOH / g • Acid-modified polyolefin-2 (PO-2) Propylene-butene-1 copolymer, melting point 84°C, molecular weight Mw 106000, acid value 9 mg KOH / g • Acid-modified polyolefin-3 (PO-3) Propylene-butene-1 copolymer, melting point 80°C, molecular weight Mw 145000, acid value 10 mg KOH / g • Acid-modified polyolefin-4 (PO-4) Propylene-butene-1 copolymer, melting point 79°C, molecular weight Mw 183000, acid value 6 mg KOH / g • Acid-modified polyolefin-5 (PO-5) Propylene-butene-1 copolymer, melting point 76°C, molecular weight Mw 118000, acid value 9 mg KOH / g • Acid-modified polyolefin-6 (PO-6) Propylene-butene-1 copolymer, melting point 84°C, molecular weight Mw 57000, acid value 23 mg KOH / g • Acid-modified polyolefin-7 (PO-7) Propylene-butene-1 copolymer, melting point 93°C, molecular weight Mw 68000, acid value 17 mg KOH / g

[0075] 2. Epoxy resin • Epoxy Resin-1 (E-1) EPICLONHP-7200 (manufactured by DIC Corporation) is an epoxy resin containing a dicyclopentadiene backbone with an epoxy equivalent of 260 g / eq. • Epoxy Resin-2 (E-2) JP-200 (manufactured by Nippon Soda Co., Ltd.), epoxidized polybutadiene, epoxy equivalent 220 g / eq. • Epoxy Resin-3 (E-3) NC-7000H (manufactured by Nippon Kayaku Co., Ltd.), naphthalene-containing cresol novolak type epoxy resin, epoxy equivalent 227 g / eq. ‧ Epoxy resin - 4 (E - 4) jER828 (manufactured by Mitsubishi Chemical Corporation), bisphenol A type epoxy resin, epoxy equivalent 190 g / eq.

[0076] 3. Curing accelerator ‧ CUREZOL C11Z (manufactured by Shikoku Chemicals Corporation, imidazole compound)

[0077] <Preparation of Liquid A> ‧ Preparation of Liquid A1 (A - 1) Dissolve 13.9 g of maleic acid - modified polyolefin (PO - 1) in a mixed solvent of 10.6 g of toluene, 14.9 g of methyl ethyl ketone, and 59.5 g of methyl cyclohexane at 60°C, and then dissolve 1.1 g of epoxy resin - 1 (E - 1) to obtain Liquid A1 (A - 1).

[0078] ‧ Preparation of Liquid A2 - Liquid A19 (A - 2 - A - 19) Except for changing the components and compounding amounts used as shown in Table 1, prepare the adhesives of A - 2 - A - 19 in the same manner as A - 1.

[0079] [Table 1]

[0080] <Preparation of Liquid B> ‧ Preparation of Liquid B1 (B - 1) Dissolve 4.0 g of CUREZOL SIZ (manufactured by Shikoku Chemicals Corporation) in a mixed solvent of 38.4 g of methyl ethyl ketone and 57.6 g of isopropyl alcohol to obtain Liquid B1 (B - 1).

[0081] ‧ Preparation of Liquid B2 and Liquid B3 (B - 2 and B - 3) Except for changing the components and compounding amounts used as shown in Table 2, prepare the adhesives of B - 2 and B - 3 in the same manner as B - 1.

[0082] [Table 2] [[ID= forty - two]]

[0083] <Preparation of adhesive composition> (Example 1) Mix 100 parts of Liquid A1 (A - 1) and 1 part of Liquid B1 (B - 1)充分混合 to prepare the adhesive composition of Example 1. It should be noted that the phrase "充分混合" in the original text seems to be a bit unclear in its expression. A more accurate or common way to say it could be "thoroughly mix". Here, I translated it as "充分混合" to follow the original text as closely as possible. If there is a more specific requirement for this part, it may need to be adjusted accordingly.

[0084] (Examples 2-13 and Comparative Examples 1-6) Except for changing the types and mixing amounts of liquids A and B as shown in Table 3 or Table 4, the adhesive compositions of Examples 2-13 and Comparative Examples 1-6 were prepared in the same manner as in Example 1.

[0085] <Layered Body> The obtained adhesive composition was coated onto a 50 μm thick aluminum foil (Al foil, untreated surface) using a bar coater to a thickness of 5 μm (dry film thickness). The solvent was evaporated at 100°C for 1 minute to obtain a coated foil. Then, the coated surface of the obtained coated foil was bonded to a 12 μm thick copper foil (Cu foil, electrolytic copper foil, untreated surface) at 100°C and cured at 80°C for 2 days to solidify the aforementioned coating, resulting in a laminate consisting of Al foil, adhesive layer, and Cu foil stacked in this order.

[0086] <Determination of Initial Peel Strength> The interfacial adhesion strength between aluminum foil and copper foil in laminates was evaluated using Shimadzu Corporation's "AUTOGRAPH AG-X" under the following conditions: peeling speed 100 mm / min, peeling width 15 mm, ambient temperature 23°C, and T-shaped peeling morphology. Units are N / mm.

[0087] <Soluble Resistance Evaluation> Prepare a commercially available electrolyte (manufactured by KISHIDA CHEMICAL Co., Ltd., ethylene carbonate: diethyl carbonate: dimethyl carbonate = 1:1:1 (volume ratio), LiPF6: 1 mol%) as the electrolyte (solvent). After immersing the laminate in an electrolyte at 60°C for 150 hours, the laminate was washed with acetone, and the peel strength was measured using the same method as the initial peel strength determination described above. This peel strength was then used as the peel strength after 150 hours of immersion. Solvent resistance was evaluated based on the peel strength after 150 hours of immersion as described below.

[0088] -Evaluation Criteria- A: The peel strength after immersion for 150 hours is above 0.7 N / mm. B: The peel strength after immersion for 150 hours is above 0.6 N / mm and below 0.7 N / mm. C: The peel strength after immersion for 150 hours is above 0.5 N / mm and below 0.6 N / mm. D: Peel strength after immersion for 150 hours is less than 0.5 N / mm.

[0089] [Table 3]

[0090] [Table 4]

[0091] As shown in Tables 3 and 4, the adhesive compositions of Examples 1-13 exhibit superior long-term chemical resistance after curing compared to the adhesive compositions of Comparative Examples 1-6.

[0092] The disclosure of Japanese Patent Application No. 2023-212416, filed on December 15, 2023, is incorporated herein by reference in its entirety. All documents, patent applications and technical standards described in this specification are incorporated herein by reference as if each document, patent application and technical standard were specifically and individually described as being incorporated by reference.

Claims

1. An adhesive composition comprising an acid-modified polyolefin and an epoxy resin, The acid-modified polyolefin satisfies the following conditions (i)-(iii). Condition (i): It is an acid-modified homopolymer of butene or an acid-modified copolymer of butene. Condition (ii): Acid value of 0.1 mg KOH / g - 15 mg KOH / g, Condition (iii): Weight-average molecular weight is above 80,000. The epoxy resin has at least one structure selected from the group consisting of dicyclopentadiene, cresol, naphthalene, and butadiene-derived building blocks. The content of the epoxy resin is 2 to 40 parts by weight relative to 100 parts by weight of the acid-modified polyolefin.

2. The adhesive composition according to claim 1, wherein, The acid-modified polyolefin is a maleic anhydride-modified polyolefin.

3. The adhesive composition according to claim 1, wherein, The acid-modified polyolefin is an acid-modified copolymer of propylene and 1-butene.

4. The adhesive composition according to claim 1, wherein, The acid value of the acid-modified polyolefin is 1 mg KOH / g-10 mg KOH / g.

5. The adhesive composition according to claim 1, wherein, The weight-average molecular weight of the acid-modified polyolefin is 90,000-200,000.

6. The adhesive composition of claim 1, further comprising a curing accelerator, said curing accelerator comprising an imidazole compound.

7. The adhesive composition according to claim 1, further comprising aromatic solvents, alicyclic solvents, and ketone solvents.

8. The adhesive composition according to claim 1, wherein it is an adhesive composition for use between metallic materials.

9. A two-component adhesive composition comprising a first reagent and a second reagent, The first reagent contains acid-modified polyolefin and epoxy resin. The acid-modified polyolefin satisfies the following conditions (i)-(iii). Condition (i): It is an acid-modified homopolymer of butene or an acid-modified copolymer of butene. Condition (ii): Acid value of 0.1 mg KOH / g - 15 mg KOH / g, Condition (iii): Weight-average molecular weight is above 80,000. The epoxy resin has at least one structure selected from the group consisting of dicyclopentadiene, cresol, naphthalene, and butadiene-derived building blocks. The content of the epoxy resin is 2 to 40 parts by weight relative to 100 parts by weight of the acid-modified polyolefin. The second reagent contains a curing accelerator.

10. The two-component adhesive composition according to claim 9, wherein, The acid-modified polyolefin is a maleic anhydride-modified polyolefin.

11. The two-component adhesive composition according to claim 9, wherein, The acid-modified polyolefin is an acid-modified copolymer of propylene and 1-butene.

12. The two-component adhesive composition according to claim 9, wherein, The acid value of the acid-modified polyolefin is 1 mg KOH / g-10 mg KOH / g.

13. The two-component adhesive composition according to claim 9, wherein, The weight-average molecular weight of the acid-modified polyolefin is 90,000-200,000.

14. The two-component adhesive composition according to claim 9, wherein, The curing accelerator contains an imidazole compound.

15. The two-component adhesive composition according to claim 9, wherein, The first reagent also includes aromatic solvents, alicyclic solvents, and ketone solvents.

16. The two-component adhesive composition according to claim 9, wherein it is a two-component adhesive composition for use between metallic materials.

17. A laminated body, which is formed by bonding a first metallic material and a second metallic material together with an adhesive. The adhesive is the adhesive composition according to any one of claims 1-8 or the two-component adhesive composition according to any one of claims 9-16.

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