Adhesive composition and laminate with adhesive layer

Abstract

Provided are an adhesive composition that can develop sufficient adhesive strength in a short heat treatment time, and a laminate with an adhesive layer that uses the same. [Solution] The adhesive composition contains a modified thermoplastic resin (A) having a reactive functional group that reacts with an epoxy group, an epoxy resin (B), a curing accelerator (C), and a metal deactivator (D). The content of the modified thermoplastic resin (A) is 50 parts by mass or more per 100 parts by mass of the solids content of the adhesive composition, the content of the epoxy resin (B) is 1 part by mass or more and 20 parts by mass or less per 100 parts by mass of the modified thermoplastic resin (A), and the content of the curing accelerator (C) is 0.15 parts by mass or more and 9 parts by mass or less per 100 parts by mass of the epoxy resin (B). The laminate with an adhesive layer includes an adhesive layer formed from the adhesive composition and a substrate film in contact with at least one side of the adhesive layer.

Description

[Technical Field]

[0001] The present invention relates to an adhesive composition and a laminate with an adhesive layer. [Background technology]

[0002] Adhesive compositions have been used in a variety of fields. For example, in printed wiring boards used in the field of electronic devices, adhesive compositions are used to bond a substrate to a copper foil or the like.

[0003] Also known are laminates with an adhesive layer, which are formed by applying an adhesive composition in the form of a layer on a desired substrate made of a resin film, etc. For example, when producing a printed wiring board, this type of laminate with an adhesive layer is used, and the board is bonded to a target adherend via the adhesive layer.

[0004] Prior Patent Document 1 discloses a technology related to an adhesive composition used to produce an insulating layer in a printed wiring board. Specifically, Patent Document 1 describes a thermosetting resin composition that maintains a low melt viscosity when heated and then cures quickly, has improved storage stability, and is less likely to cause an increase in the linear thermal expansion coefficient of the cured product. The thermosetting resin composition contains a radically polymerizable unsaturated compound (A), a thermal radical polymerization initiator (B), and an organic radical compound (C), the organic radical compound (C) contains an organic nitroxide radical compound (C1), the amount of the thermal radical polymerization initiator (B) is 0.1 to 5 parts by mass per 100 parts by mass of the radically polymerizable unsaturated compound (A), and the amount of the organic radical compound (C) relative to the radically polymerizable unsaturated compound (A) is 0.01 to 5.0% by mass.

[0005] Furthermore, Patent Document 2 discloses a technique relating to a method for manufacturing a printed wiring board provided with an electromagnetic wave shielding sheet. Patent Document 2 describes a laminate of "polyimide film / electromagnetic wave shielding sheet / thermosetting adhesive sheet / polyimide film" that has a peel strength of about 6 N / 25 mm. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 7450224

[0007] [Patent Document 2] Patent No. 6409760 Summary of the Invention [Problem to be solved by the invention]

[0008] When a product is manufactured using an adhesive composition or a laminate with an adhesive layer, it is necessary from the viewpoint of productivity to develop sufficient adhesive strength in a short heat treatment time. For example, the above-mentioned printed wiring board is manufactured by laminating an adhesive layer formed from the adhesive composition onto a surface having wiring by hot roll lamination, hot press, or the like, and laminating the resulting product. In this case, from the viewpoint of productivity, it is necessary to develop sufficient adhesive strength in a short heat treatment time.

[0009] The present invention has been made in view of the above problems, and aims to provide an adhesive composition that can exhibit sufficient adhesive strength in a short heat treatment time, and a laminate with an adhesive layer that uses the same. [Means for solving the problem]

[0010] The adhesive composition and the laminate with an adhesive layer according to the present invention are as follows. [1] a modified thermoplastic resin (A) having a reactive functional group that reacts with an epoxy group; an epoxy resin (B); a curing accelerator (C); and a metal deactivator (D), the content of the modified thermoplastic resin (A) is 50 parts by mass or more per 100 parts by mass of the solid content of the adhesive composition, the content of the epoxy resin (B) is 1 part by mass or more and 20 parts by mass or less per 100 parts by mass of the modified thermoplastic resin (A), The content of the curing accelerator (C) is 0.15 parts by mass or more and 9 parts by mass or less per 100 parts by mass of the epoxy resin (B). Adhesive composition. [2] The modified thermoplastic resin (A) is a resin obtained by graft-modifying an unmodified thermoplastic resin with a modifying agent containing an α,β-unsaturated carboxylic acid or a derivative thereof. [1] The adhesive composition according to [1]. [3] The unmodified thermoplastic resin is at least one selected from the group consisting of a styrene-based elastomer, an ethylene-propylene copolymer, a propylene-butene copolymer, and an ethylene-propylene-butene copolymer. [2] The adhesive composition according to [2]. [4] the unmodified thermoplastic resin is a styrene-based elastomer, The adhesive composition has a gel fraction of 45% or more and 91% or less when cured at 190°C for 30 minutes. [2] The adhesive composition according to [2]. [5] The curing accelerator (C) is at least one selected from the group consisting of a tertiary amine curing accelerator, a tertiary amine salt curing accelerator, and an imidazole curing accelerator. [1] to [4] The adhesive composition according to any one of [1] to [4]. [6] The metal deactivator (D) contains at least one skeleton selected from the group consisting of a hydrazide skeleton, a triazine skeleton, and a hindered phenol skeleton. [1] to [5]. The adhesive composition according to any one of [1] to [5]. [7] the content of the metal deactivator (D) is 0.03 parts by mass or more and 2 parts by mass or less per 100 parts by mass of the solid content of the adhesive composition; [1] to [6], the adhesive composition according to any one of [1] to [6]. [8] A laminate with an adhesive layer, comprising an adhesive layer formed from the adhesive composition according to any one of [1] to [7] and a substrate film in contact with at least one side of the adhesive layer. [Effects of the Invention]

[0011] The adhesive composition has the above-mentioned configuration. That is, the adhesive composition contains a modified thermoplastic resin (A) and an epoxy resin (B), and further contains a curing accelerator (C) and a metal deactivator (D), and the contents of the modified thermoplastic resin (A), the epoxy resin (B), and the curing accelerator (C) are set to specific ranges. Therefore, when the adhesive composition forms an adhesive layer that is cured by heat treatment to bond, it is possible to develop sufficient adhesive strength in a short heat treatment time.

[0012] Furthermore, the laminate with an adhesive layer includes an adhesive layer formed from the adhesive composition, and therefore, when the adhesive layer is cured by heat treatment to bond the laminate with the adhesive layer, it is possible to achieve sufficient adhesive strength in a short heat treatment time. DETAILED DESCRIPTION OF THE INVENTION

[0013] An embodiment of the present invention will be described below, but the present invention is not limited to the examples shown in the following embodiment. Furthermore, the lower and upper limits of the numerical ranges shown below can be arbitrarily combined (omitted below).

[0014] 1. Adhesive composition The adhesive composition of this embodiment contains a modified thermoplastic resin (A), an epoxy resin (B), a curing accelerator (C), and a metal deactivator (D). The composition of the adhesive composition will be specifically described below.

[0015] 1.1 Modified thermoplastic resin (A) In the adhesive composition of this embodiment, the modified thermoplastic resin (A) is an important adhesive component that serves as the base of the adhesive composition.

[0016] The modified thermoplastic resin (A) has a reactive functional group that reacts with an epoxy group. That is, the modified thermoplastic resin (A) can be said to be an unmodified thermoplastic resin into which a reactive functional group that reacts with an epoxy group has been introduced, or it can be said to be a resin obtained by modifying an unmodified thermoplastic resin with a modifier having a reactive functional group that reacts with an epoxy group, or it can be said to be a resin obtained by modifying an unmodified thermoplastic resin so as to have reactivity with the epoxy resin (B).

[0017] Examples of reactive functional groups that react with epoxy groups include groups having active hydrogen and active ester groups. Examples of groups having active hydrogen include carboxy groups, amino groups, hydroxyl groups, acid anhydride groups, and thiol groups. These can be used alone or in combination of two or more. From the viewpoint of reactivity, the reactive functional group that reacts with epoxy groups is preferably a carboxy group or an amino group, and more preferably a carboxy group.

[0018] The modified thermoplastic resin (A) may be a resin having a structural portion derived from an unmodified thermoplastic resin and a structural portion derived from a modifying agent having a reactive functional group that reacts with an epoxy group. The modified thermoplastic resin (A) is preferably an acid-modified thermoplastic resin, and more specifically, a resin obtained by graft-modifying an unmodified thermoplastic resin with a modifying agent containing an α,β-unsaturated carboxylic acid or a derivative thereof.

[0019] In this case, more specifically, the modified thermoplastic resin (A) can have a structural portion derived from an unmodified thermoplastic resin and a structural portion derived from an α,β-unsaturated carboxylic acid or a derivative thereof. The proportion of the structural portion derived from an α,β-unsaturated carboxylic acid or a derivative thereof in the modified thermoplastic resin (A) can preferably be 0.1% by mass or more and 20% by mass or less. When the proportion of the structural portion derived from an α,β-unsaturated carboxylic acid or a derivative thereof is 0.1% by mass or more, the modified thermoplastic resin (A) has excellent solubility in solvents and particularly excellent adhesion to adherends made of metals, etc. On the other hand, when the proportion of the structural portion derived from an α,β-unsaturated carboxylic acid or a derivative thereof is 20% by mass or less, sufficient adhesion to adherends made of resins, etc. can be obtained.

[0020] The proportion of the structural moiety derived from an α,β-unsaturated carboxylic acid or a derivative thereof is preferably 0.15% by mass or more, more preferably 0.2% by mass or more, and even more preferably 0.3% by mass or more. Furthermore, the proportion of the structural moiety derived from an α,β-unsaturated carboxylic acid or a derivative thereof is preferably 19% by mass or less, more preferably 18% by mass or less, and even more preferably 15% by mass or less. By controlling the structural moiety derived from an α,β-unsaturated carboxylic acid compound within the above range, solubility in solvents can be increased, and adhesion to adherends made of metals, resins, etc. can also be further improved.

[0021] Examples of unmodified thermoplastic resins used to form the modified thermoplastic resin (A) include styrene elastomers, polyolefin resins, etc. In this case, more specifically, the modified thermoplastic resin (A) can be composed of an acid-modified styrene elastomer obtained by graft-modifying an unmodified styrene elastomer with a modifying agent containing an α,β-unsaturated carboxylic acid or a derivative thereof, or an acid-modified polyolefin resin obtained by graft-modifying an unmodified polyolefin resin with a modifying agent containing an α,β-unsaturated carboxylic acid or a derivative thereof.

[0022] Examples of the styrene-based elastomer include styrene-butadiene block copolymer (SB), styrene-ethylene propylene block copolymer (SEP), styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), styrene-ethylenebutylene-styrene block copolymer (SEBS), styrene-ethylenepropylene-styrene block copolymer (SEPS), and styrene-(ethylene-ethylene / propylene)-styrene block copolymer (SEEPS). These can be used alone or in combination of two or more. Of these, styrene-ethylenebutylene-styrene block copolymer (SEBS) is preferred from the viewpoint of adhesiveness, etc.

[0023] The polyolefin resin is not particularly limited as long as it has a structural unit derived from an olefin, but a homopolymer or copolymer having 2 to 20 carbon atoms, such as ethylene, propylene, butene, pentene, hexene, heptene, octene, or 4-methyl-1-pentene, is preferably used. The polyolefin resin is more preferably a homopolymer or copolymer of an olefin having 2 to 6 carbon atoms. Specific examples of the polyolefin resin include an ethylene-propylene copolymer, a propylene-butene copolymer, and an ethylene-propylene-butene copolymer. These can be used alone or in combination of two or more.

[0024] The modified thermoplastic resin (A) can be produced by graft modification (graft polymerization) using known methods, and a radical initiator may be used during production. Examples of methods for producing the modified thermoplastic resin (A) include a solution method in which the desired unmodified thermoplastic resin is heated and dissolved in a solvent such as toluene, and the modifier and radical initiator are added, and a melt method in which the desired unmodified thermoplastic resin, modifier, and radical initiator are melt-kneaded using a Banbury mixer, kneader, extruder, or the like. The method for using the desired unmodified thermoplastic resin, modifier, and radical initiator is not particularly limited; they may be added to the reaction system all at once or sequentially. Furthermore, when producing the modified thermoplastic resin (A), a modification aid for improving the grafting efficiency of the modifier, such as an α,β-unsaturated carboxylic acid, and a stabilizer for adjusting the resin stability may also be used.

[0025] The modifier may include an α,β-unsaturated carboxylic acid and its derivative. Examples of the α,β-unsaturated carboxylic acid include maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, aconitic acid, and norbornene dicarboxylic acid. Derivatives of unsaturated carboxylic acids include acid anhydrides, acid halides, amides, imides, and esters. Preferred modifiers include itaconic anhydride, maleic anhydride, aconitic anhydride, and citraconic anhydride, with itaconic anhydride and maleic anhydride being particularly preferred in terms of adhesiveness. When a modifier is used, it may be one or more selected from α,β-unsaturated carboxylic acids and their derivatives. Examples of the modifier include a combination of one or more α,β-unsaturated carboxylic acids and one or more derivatives thereof, a combination of two or more α,β-unsaturated carboxylic acids, or a combination of two or more derivatives of α,β-unsaturated carboxylic acids.

[0026] 1.2 Epoxy resin (B) In the adhesive composition of this embodiment, the epoxy resin (B) reacts with the reactive functional groups of the modified thermoplastic resin (A) and is an important component for imparting adhesion to the adherend and heat resistance to the cured product of the adhesive composition.

[0027] Examples of the epoxy resin (B) include bisphenol A type epoxy resins, bisphenol F type epoxy resins, and hydrogenated versions thereof; glycidyl ester-based epoxy resins such as orthophthalic acid diglycidyl ester, isophthalic acid diglycidyl ester, terephthalic acid diglycidyl ester, p-hydroxybenzoic acid glycidyl ester, tetrahydrophthalic acid diglycidyl ester, succinic acid diglycidyl ester, adipic acid diglycidyl ester, sebacic acid diglycidyl ester, and trimellitic acid triglycidyl ester; ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, and the like. Examples of epoxy resins that can be used include, but are not limited to, glycidyl ether-based epoxy resins such as diol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, tetraphenylglycidyl ether ethane, triphenylglycidyl ether ethane, sorbitol polyglycidyl ether, and polyglycerol polyglycidyl ether; glycidylamine-based epoxy resins such as triglycidyl isocyanurate and tetraglycidyldiaminodiphenylmethane; and linear aliphatic epoxy resins such as epoxidized polybutadiene and epoxidized soybean oil. Additionally, novolac-type epoxy resins such as phenol novolac epoxy resin, o-cresol novolac epoxy resin, and bisphenol A novolac epoxy resin can also be used.

[0028] Further, examples of the epoxy resin (B) include brominated bisphenol A type epoxy resins, phosphorus-containing epoxy resins, epoxy resins having a dicyclopentadiene skeleton, epoxy resins having a naphthalene skeleton, anthracene type epoxy resins, tertiary butylcatechol type epoxy resins, triphenylmethane type epoxy resins, tetraphenylethane type epoxy resins, biphenyl type epoxy resins, bisphenol S type epoxy resins, etc. These epoxy resins (B) may be used alone or in combination of two or more.

[0029] The epoxy resin (B) preferably has two or more epoxy groups in one molecule, because this forms a crosslinked structure by reaction with the modified thermoplastic resin (A), thereby enabling high heat resistance to be exhibited.

[0030] As the epoxy resin (B), from the viewpoint of ensuring the development of sufficient adhesive strength in a short heat treatment time, polyfunctional epoxy resins having an alicyclic skeleton, epoxy resins having a polycyclic aromatic hydrocarbon skeleton, etc. These can be used alone or in combination of two or more.

[0031] 1.3 Curing accelerator (C) The curing accelerator (C) is a component intended to accelerate the reaction between the modified thermoplastic resin (A) and the epoxy resin (B).

[0032] As the curing accelerator (C), from the viewpoint of accelerating the reaction between the modified thermoplastic resin (A) and the epoxy resin (B), tertiary amine curing accelerators, tertiary amine salt curing accelerators, imidazole curing accelerators, etc. can be suitably used. These may be used alone or in combination of two or more.

[0033] Examples of tertiary amine curing accelerators include benzyldimethylamine, 2-(dimethylaminomethyl)phenol, 2,4,6-tris(dimethylaminomethyl)phenol, tetramethylguanidine, triethanolamine, N,N'-dimethylpiperazine, triethylenediamine, and 1,8-diazabicyclo[5.4.0]undecene.

[0034] Examples of tertiary amine salt curing accelerators include formate, octylate, p-toluenesulfonate, o-phthalate, phenolate, and phenol novolac resin salt of 1,8-diazabicyclo[5.4.0]undecene; and formate, octylate, p-toluenesulfonate, o-phthalate, phenolate, and phenol novolac resin salt of 1,5-diazabicyclo[4.3.0]nonene.

[0035] Examples of the imidazole curing accelerator include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-methyl-4-ethylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 2,4-diamino-6-[2'-methylimidazolyl-(1')]ethyl-s-triazine, 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-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and the like.

[0036] 1.4 Metal deactivator (D) The metal deactivator (D) is an important component in an adhesive composition system containing a modified thermoplastic resin (A) and an epoxy resin (B), because, when used in combination with a curing accelerator (C), it increases the gel fraction after curing and improves adhesive strength.

[0037] As the metal deactivator (D), one containing at least one skeleton selected from the group consisting of a hydrazide skeleton, a triazine skeleton, and a hindered phenol skeleton can be suitably used, from the viewpoint that the gel fraction after curing can be increased to a suitable range by using it in combination with the curing accelerator (C) and the peel strength can be improved, etc. These may be used alone or in combination of two or more.

[0038] Examples of the metal deactivator (D) containing a hydrazide skeleton include N'1,N'12-bis(2-hydroxybenzoyl)dodecane dihydrazide.

[0039] Examples of the metal deactivator (D) containing a triazine skeleton include N-(2H-1,2,4-triazol-5-yl) salicylamide.

[0040] Examples of the metal deactivator (D) containing a hindered phenol skeleton include N,N'-bis[2-[2-(3,5-di-tert-butyl-4-hydroxyphenyl)ethylcarbonyloxy]ethyl]oxamide.

[0041] Examples of the metal deactivator (D) containing a hydrazide skeleton and a hindered phenol skeleton include 1,2'-bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propynyl]hydrazine.

[0042] 1.5 Ingredient content 1.5.1 Content of modified thermoplastic resin (A) In the adhesive composition, the content of the modified thermoplastic resin (A) is 50 parts by mass or more per 100 parts by mass of the solid content of the adhesive composition. In this disclosure, "solid content" refers to the components excluding the solvent. If the content of the modified thermoplastic resin (A) is less than 50 parts by mass per 100 parts by mass of the solid content of the adhesive composition, the adhesive components will not be sufficiently secured, making it difficult to secure adhesion to the adherend.

[0043] From the viewpoint of adhesion to the adherend, the content of the modified thermoplastic resin (A) is preferably 55 parts by mass or more, more preferably 60 parts by mass or more, and even more preferably 65 parts by mass or more, per 100 parts by mass of the solid content of the adhesive composition. From the viewpoint of adhesion to the adherend, the content of the modified thermoplastic resin (A) is preferably 99 parts by mass or less, more preferably 97 parts by mass or less, and even more preferably 95 parts by mass or less, per 100 parts by mass of the solid content of the adhesive composition.

[0044] 1.5.2 Epoxy resin (B) content In the adhesive composition, the content of the epoxy resin (B) is 1 part by mass or more and 20 parts by mass or less per 100 parts by mass of the modified thermoplastic resin (A). If the content of the epoxy resin (B) is less than 1 part by mass per 100 parts by mass of the modified thermoplastic resin (A), the reactivity with the reactive groups in the modified thermoplastic resin (A) decreases, resulting in an excessively small gel fraction after curing. On the other hand, if the content of the epoxy resin (B) is more than 20 parts by mass per 100 parts by mass of the modified thermoplastic resin (A), the gel fraction after curing becomes excessively large, making it impossible to achieve sufficient adhesive strength with a short heat treatment time.

[0045] The content of the epoxy resin (B) is preferably 1.5 parts by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more, per 100 parts by mass of the modified thermoplastic resin (A), from the viewpoint of achieving sufficient adhesiveness, etc. The content of the epoxy resin (B) is preferably 19 parts by mass or less, more preferably 18 parts by mass or less, and even more preferably 15 parts by mass or less, per 100 parts by mass of the modified thermoplastic resin (A), from the viewpoint of achieving sufficient adhesiveness and heat resistance, as well as peel strength and electrical properties.

[0046] 1.5.3 Content of hardening accelerator (C) In the adhesive composition, the content of the curing accelerator (C) is 0.15 to 9 parts by mass per 100 parts by mass of the epoxy resin (B). If the content of the curing accelerator (C) is less than 0.15 parts by mass per 100 parts by mass of the epoxy resin (B), the gel fraction of the cured product will not increase sufficiently in a short heat treatment time, making it difficult to achieve sufficient adhesive strength. On the other hand, if the content of the curing accelerator (C) is more than 9 parts by mass per 100 parts by mass of the epoxy resin (B), the gel fraction of the cured product will become excessively large in a short heat treatment time, increasing the risk of reducing adhesive strength.

[0047] The content of the curing accelerator (C) is preferably 0.2 parts by mass or more, more preferably 0.25 parts by mass or more, and even more preferably 0.3 parts by mass or more, relative to 100 parts by mass of the epoxy resin (B), from the viewpoint of developing sufficient adhesive strength, etc. The content of the curing accelerator (C) is preferably 8 parts by mass or less, more preferably 7 parts by mass or less, and even more preferably 6 parts by mass or less, relative to 100 parts by mass of the epoxy resin (B), from the viewpoint of developing sufficient adhesive strength, etc.

[0048] 1.5.4 Metal Deactivator (D) Content In the adhesive composition, the content of the metal deactivator (D) can be 0.03 parts by mass or more and 2 parts by mass or less per 100 parts by mass of the solid content of the adhesive composition. When the content of the metal deactivator (D) is 0.03 parts by mass or more per 100 parts by mass of the solid content of the adhesive composition, the gel fraction of the cured product increases in a short heat treatment time, and sufficient adhesiveness can be achieved. On the other hand, when the content of the metal deactivator (D) is 2 parts by mass or less per 100 parts by mass of the solid content of the adhesive composition, an excessively large gel fraction after curing can be prevented.

[0049] The content of the metal deactivator (D) is preferably 0.04 parts by mass or more, more preferably 0.05 parts by mass or more, and even more preferably 0.06 parts by mass or more, per 100 parts by mass of the solid content of the adhesive composition, from the viewpoint of developing sufficient adhesive strength, etc. Furthermore, the content of the metal deactivator (D) is preferably 1.9 parts by mass or less, more preferably 1.8 parts by mass or less, and even more preferably 1.5 parts by mass or less, per 100 parts by mass of the solid content of the adhesive composition, from the viewpoint of developing sufficient adhesive strength, etc.

[0050] 1.6 Other ingredients In addition to the above-mentioned modified thermoplastic resin (A), epoxy resin (B), curing accelerator (C), and metal deactivator (D), the adhesive composition of this embodiment may contain, for example, an unmodified thermoplastic resin, a tackifier, a flame retardant, a curing agent, a coupling agent, a heat aging inhibitor, an inorganic filler, a leveling agent, an antifoaming agent, a pigment, an ultraviolet absorber, a lubricant, a solvent, and the like, to an extent that does not affect the functionality of the adhesive composition.

[0051] (unmodified thermoplastic resin) Examples of unmodified thermoplastic resins that can be contained in the adhesive composition as other resin components include the above-mentioned styrene-based elastomers (unmodified), the above-mentioned polyolefin-based resins (unmodified), phenoxy resins, polyamide resins, polyester resins, polycarbonate resins, polyphenylene oxide resins, polyurethane resins, polyacetal resins, and polyvinyl-based resins. These unmodified thermoplastic resins may be used alone or in combination of two or more.

[0052] (tackifier) Examples of the tackifier include coumarone-indene resins, terpene resins, terpene-phenol resins, rosin resins, pt-butylphenol-acetylene resins, phenol-formaldehyde resins, xylene-formaldehyde resins, petroleum-based hydrocarbon resins, hydrogenated hydrocarbon resins, turpentine-based resins, etc. These tackifiers may be used alone or in combination of two or more.

[0053] (Flame retardant) The flame retardant may be either an organic flame retardant or an inorganic flame retardant. Examples of organic flame retardants include phosphorus-based flame retardants such as melamine phosphate, melamine polyphosphate, guanidine phosphate, guanidine polyphosphate, ammonium phosphate, ammonium polyphosphate, ammonium amido phosphate, ammonium amido polyphosphate, carbamate phosphate, carbamate polyphosphate, aluminum trisdiethylphosphinate, aluminum trismethylethylphosphinate, aluminum trisdiphenylphosphinate, zinc bisdiethylphosphinate, zinc bismethylethylphosphinate, zinc bisdiphenylphosphinate, titanyl bisdiethylphosphinate, titanium tetrakisdiethylphosphinate, titanyl bismethylethylphosphinate, titanium tetrakismethylethylphosphinate, titanyl bisdiphenylphosphinate, and titanium tetrakisdiphenylphosphinate; nitrogen-based flame retardants such as triazine-based compounds such as melamine, melam, and melamine cyanurate, cyanuric acid compounds, isocyanuric acid compounds, triazole-based compounds, tetrazole compounds, diazo compounds, and urea; and silicon-based flame retardants such as silicone compounds and silane compounds. Examples of inorganic flame retardants include metal hydroxides such as aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, barium hydroxide, and calcium hydroxide; metal oxides such as tin oxide, aluminum oxide, magnesium oxide, zirconium oxide, zinc oxide, molybdenum oxide, and nickel oxide; zinc carbonate, magnesium carbonate, barium carbonate, zinc borate, and hydrated glass. These flame retardants may be used alone or in combination of two or more.

[0054] (hardening agent) Examples of the curing agent include, but are not limited to, amine-based curing agents and acid anhydride-based curing agents. Examples of the amine-based curing agent include melamine resins such as methylated melamine resin, butylated melamine resin, and benzoguanamine resin, dicyandiamide, and 4,4'-diphenyldiaminosulfone. Examples of the acid anhydride include aromatic acid anhydrides and aliphatic acid anhydrides. These curing agents may be used alone or in combination of two or more.

[0055] (coupling agent) Examples of the coupling agent include silane-based coupling agents such as vinyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, bis(triethoxysilylpropyl)tetrasulfide, 3-isocyanatepropyltriethoxysilane, and imidazolesilane; titanate-based coupling agents; aluminate-based coupling agents; and zirconium-based coupling agents. These may be used alone or in combination of two or more.

[0056] (thermal antioxidant) Examples of the heat aging inhibitor include antioxidants, and specific examples thereof include 2,6-di-tert-butyl-4-methylphenol, n-octadecyl-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate, tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methane, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenol, triethylene Examples of antioxidants include phenolic antioxidants such as ethylene glycol-bis[3-(3-t-butyl-5-methyl-4-hydroxyphenyl)propionate]; sulfur-based antioxidants such as dilauryl-3,3'-thiodipropionate and dimyristyl-3,3'-dithiopropionate; and phosphorus-based antioxidants such as trisnonylphenyl phosphite and tris(2,4-di-tert-butylphenyl)phosphite. These antioxidants may be used alone or in combination of two or more.

[0057] (inorganic filler) Examples of the inorganic filler include powders of titanium oxide, aluminum oxide, zinc oxide, carbon black, silica, talc, copper, silver, etc. These may be used alone or in combination of two or more.

[0058] (lubricant) Examples of the lubricant include oleic acid amide, stearic acid amide, erucic acid amide, etc. These may be used alone or in combination of two or more.

[0059] (solvent) The adhesive composition of this embodiment can be produced by mixing a modified thermoplastic resin (A), an epoxy resin (B), a curing accelerator (C), a metal deactivator (D), and, if necessary, other components. The mixing method is not particularly limited as long as the adhesive composition is homogeneous. Since the adhesive composition is preferably used in the form of a solution or dispersion, a solvent such as an organic solvent is usually also used.

[0060] Examples of solvents include alcohols such as methanol, ethanol, isopropyl alcohol, n-propyl alcohol, isobutyl alcohol, n-butyl alcohol, benzyl alcohol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, and diacetone alcohol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone, cyclohexanone, and isophorone; aromatic hydrocarbons such as toluene, xylene, ethylbenzene, and mesitylene; esters such as methyl acetate, ethyl acetate, ethylene glycol monomethyl ether acetate, and 3-methoxybutyl acetate; and aliphatic hydrocarbons such as hexane, heptane, cyclohexane, and methylcyclohexane. These solvents may be used alone or in combination of two or more. When the adhesive composition contains a solvent and is a solution or dispersion (resin varnish) in which each component is dissolved or dispersed in the solvent, coating onto a substrate film and forming an adhesive layer can be carried out smoothly, and an adhesive layer of the desired thickness can be easily obtained.

[0061] 1.7 Gel fraction when adhesive composition is cured In the adhesive composition, when the unmodified thermoplastic resin used to constitute the modified thermoplastic resin (A) is a styrene-based elastomer, the adhesive composition preferably has a gel fraction of 45% or more and 91% or less when cured for 30 minutes at 190° C. When the gel fraction after curing under specific heat treatment conditions is within the above range, the effect of the present disclosure, that is, sufficient adhesive strength can be achieved with a short heat treatment time, can be more clearly achieved.

[0062] The gel fraction is preferably 46% or more, more preferably 48% or more, and even more preferably 50% or more, from the viewpoint of achieving sufficient adhesive strength in a short heat treatment time. The gel fraction is preferably 90% or less, more preferably 89% or less, and even more preferably 88% or less, from the viewpoint of achieving sufficient adhesive strength in a short heat treatment time. The method for measuring the gel fraction will be described in detail in the Examples below.

[0063] 1.8 Dielectric properties of cured adhesive compositions 1.8.1 Dielectric constant of the cured adhesive composition The dielectric constant (Dk, εr) of the cured adhesive composition measured at a frequency of 1 GHz is preferably less than 3.0. A dielectric constant of less than 3.0 can be used favorably in FPC-related products, which have strict requirements for dielectric properties in response to the recent trend toward ever-increasing signal speeds and ever-higher signal frequencies. The dielectric constant is preferably 2.8 or less, more preferably 2.7 or less, and even more preferably 2.6 or less. The dielectric constant can be adjusted by the type and content of each component in the adhesive composition. The method for measuring the dielectric constant will be described in detail in the Examples below.

[0064] 1.8.2 Dielectric loss tangent of the cured adhesive composition The adhesive composition of this embodiment preferably has a dielectric loss tangent (Df, tanδ) of less than 0.03 when measured at a frequency of 1 GHz. A dielectric loss tangent of less than 0.03 allows the adhesive composition to be suitably used in FPC-related products, which have stringent dielectric property requirements in response to the recent trend toward ever-increasing signal speeds and ever-higher signal frequencies. The dielectric loss tangent is preferably 0.025 or less, more preferably 0.02 or less, even more preferably 0.015 or less, even more preferably 0.01 or less, and particularly preferably 0.005 or less. The dielectric loss tangent can be measured in the same manner as the method for measuring the relative dielectric constant, which will be described in detail in the Examples below.

[0065] 1.9 Uses of adhesive compositions The adhesive composition of the present embodiment can be suitably used for, for example, flexible copper-clad laminates, rigid copper-clad laminates, flexible flat cables, sealing materials, and the like.

[0066] The flexible copper-clad laminate can be configured to have a substrate film on one side of the adhesive layer of the laminate with an adhesive layer described below, and a copper foil on the other side of the adhesive layer. Specifically, the flexible copper-clad laminate can be configured to have a substrate film and copper foil bonded together using the laminate with an adhesive layer described below. That is, the flexible copper-clad laminate can be configured to have a substrate film, an adhesive layer, and copper foil laminated in this order. The adhesive layer and copper foil may be formed on both sides of the substrate film.

[0067] The rigid copper-clad laminate can be configured to include a plate-shaped substrate made of glass epoxy or the like on one side of an adhesive layer made of the adhesive composition, and a copper foil on the other side of the adhesive layer. Specifically, the rigid copper-clad laminate can be configured in such a way that the substrate and copper foil are bonded together using an adhesive layer made of the adhesive composition. That is, the rigid copper-clad laminate can be configured to include the substrate, adhesive layer, and copper foil laminated in this order. The adhesive layer and copper foil may be formed on both sides of the substrate.

[0068] The flexible flat cable can be configured to have a base film on one side of the adhesive layer of a laminate with an adhesive layer described below, and a copper wiring on the other side of the adhesive layer. Specifically, the flexible flat cable can be configured to have a base film and copper wiring bonded together using a laminate with an adhesive layer described below. That is, the flexible flat cable can be configured to have a base film, an adhesive layer, and copper wiring laminated in this order. The adhesive layer and copper wiring may be formed on both sides of the base film.

[0069] The encapsulant may have a configuration in which a substrate film is provided on one side of the adhesive layer in a laminate with an adhesive layer described below, and a substrate film is provided on the other side of the adhesive layer. That is, the encapsulant may be one in which the substrate film, adhesive layer, and substrate film are laminated in this order.

[0070] Furthermore, the adhesive composition of this embodiment can also be suitably used for electronic materials, automotive applications, and the like, in addition to the applications for flexible printed circuit (FPC) related products described above.

[0071] 2. Laminate with adhesive layer The laminate with an adhesive layer according to this embodiment includes an adhesive layer made of the adhesive composition described above and a substrate film in contact with at least one surface of the adhesive layer. The adhesive layer may be in a B-stage state. The B-stage state of the adhesive layer refers to a semi-cured state in which part of the adhesive composition has begun to harden, and refers to a state in which the hardening of the adhesive composition progresses further by heating or the like.

[0072] One embodiment of the adhesive layer-attached laminate is a coverlay film, which is typically a laminate in which an adhesive layer is formed on at least one surface of a substrate film, making it difficult to peel the substrate film and the adhesive layer from each other.

[0073] Examples of the substrate film included in the laminate with an adhesive layer include a polyimide film, a polyether ether ketone film, a polyphenylene sulfide film, an aramid film, a polyethylene naphthalate film, a liquid crystal polymer film, etc. Among these, from the viewpoints of adhesiveness and electrical properties, a polyimide film, a polyethylene naphthalate film, and a liquid crystal polymer film are preferred.

[0074] As a method for producing a laminate with an adhesive layer, for example, a resin varnish containing the above-mentioned adhesive composition and a solvent is applied to the surface of a substrate film such as a polyimide film to form a resin varnish layer, and then the solvent is removed from this resin varnish layer, thereby producing a laminate with an adhesive layer formed thereon.

[0075] The drying temperature when removing the solvent is preferably 40 to 250° C., more preferably 70 to 170° C. Drying can be carried out by passing the laminate coated with the adhesive composition through a furnace that performs hot air drying, far-infrared heating, high-frequency induction heating, or the like.

[0076] If necessary, a release film may be laminated on the surface of the adhesive layer for storage, etc. As the release film, known films such as polyethylene terephthalate film, polyethylene film, polypropylene film, silicone release-treated paper, polyolefin resin-coated paper, polymethylpentene (TPX) film, and fluororesin film can be used.

[0077] Another embodiment of the laminate with an adhesive layer is a bonding sheet. The bonding sheet also has the above-mentioned adhesive layer formed on the surface of a base film, but the base film functions as a release film. The bonding sheet may also have an adhesive layer between two release films. The release films are peeled off when the bonding sheet is used. The release films may be the same as those described above.

[0078] A bonding sheet can be produced, for example, by applying a resin varnish containing the adhesive composition and a solvent to the surface of a release film and drying it in the same manner as in the case of the coverlay film.

[0079] In the laminate with an adhesive layer, the thickness of the adhesive layer can be preferably 5 μm or more and 100 μm or less, more preferably 10 μm or more and 70 μm or less, and even more preferably 10 μm or more and 50 μm or less, in order to fully exhibit adhesive strength. Also, the thickness of the base film can be preferably 5 μm or more and 100 μm or less, more preferably 5 μm or more and 50 μm or less, and even more preferably 5 μm or more and 30 μm or less, in order to reduce the thickness of the laminate with an adhesive layer. [Example]

[0080] The present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. In the following, parts and percentages are by mass unless otherwise specified.

[0081] 1. Evaluation Method (1) Weight average molecular weight Mw GPC measurement was carried out under the following conditions to determine the weight average molecular weight Mw of the modified thermoplastic resin (A). The weight average molecular weight Mw was calculated by converting the retention time measured by GPC based on the retention time of standard polystyrene. Apparatus: Alliance 2695 (Waters) Column: TSKgel SuperMultiporeHZ-H (2 columns), Two TSKgel SuperHZ2500 (manufactured by Tosoh Corporation) Column temperature: 40℃ Eluent: tetrahydrofuran 0.35 ml / min Detector: RI (differential refractive index detector)

[0082] (2) Acid value 1 g of modified thermoplastic resin (A) was dissolved in 30 ml of toluene, and an automatic titrator "AT-510" manufactured by Kyoto Electronics Manufacturing Co., Ltd., connected to the "APB-510-20B" buret, was used. Potentiometric titration was performed using a 0.01 mol / L benzyl alcohol KOH solution as the titration reagent, and the mg of KOH per 1 g of resin was calculated.

[0083] (3) Gel fraction of adhesive composition after curing The adhesive layer cured at 190°C for 30 minutes (both when an acid-modified styrene-based elastomer was used as the modified thermoplastic resin (A) and when an acid-modified polyolefin-based resin was used as the modified thermoplastic resin (A)) or the adhesive layer cured at 170°C for 30 minutes (only when an acid-modified polyolefin-based resin was used as the modified thermoplastic resin (A)) was cut out from the sample to a size of approximately 0.5 to 1.0 g, and the exact mass M1 before immersion in the organic solvent was measured using a precision balance. Next, the adhesive layer was wrapped in a 200-mesh metal mesh and placed in a 140 mL container. 30 g of organic solvent was added to this, and the mixture was heated and extracted at 80°C for 2 hours. When an acid-modified styrene-based elastomer was used as the modified thermoplastic resin (A), the organic solvent used was toluene / MEK = 10 / 1 (mass ratio). When an acid-modified polyolefin-based resin was used as the modified thermoplastic resin (A), the organic solvent used was methylcyclohexane / toluene / MEK = 5 / 2 / 1 (mass ratio). After cooling at room temperature for 1 hour, the adhesive layer after immersion in the organic solvent was completely dried using a vacuum dryer.The mass M2 of the completely dried adhesive layer was then measured using a precision balance.The gel fraction (%) of the adhesive composition after curing was then calculated using the following formula. Gel fraction (%) = 100 × M2 / M1 however, M1: Mass of the adhesive layer cured at the above-mentioned specified temperature for the specified time before immersion in the organic solvent M2: Mass of the adhesive layer that has been immersed in an organic solvent, dried completely, and cured for a specified time at the specified temperature above

[0084] (4) Peel adhesion strength of the cured product of the adhesive composition A copper-clad laminate (a laminate of a 25 μm-thick polyimide film and an 18 μm-thick copper foil) was prepared, and the surface of the polyimide film was roll-coated with a liquid adhesive composition listed in Tables 1 to 3. The coated film was then placed in an oven and dried at 90°C for 3 minutes to form a B-stage adhesive layer (25 μm thick), yielding a laminate with an adhesive layer. A 35 μm-thick rolled copper foil was then placed on top of the adhesive layer of the laminate so that it was in surface contact with the adhesive layer, and lamination was performed at a temperature of 120°C, a pressure of 0.4 MPa, and a speed of 0.5 m / min. This laminate (copper-clad laminate / adhesive layer / copper foil) was then heat-cured at a temperature of 190°C and a pressure of 3 MPa for 30 minutes, or at a temperature of 170°C and a pressure of 3 MPa for 30 minutes, yielding a flexible copper-clad laminate. The resulting flexible copper-clad laminate was then cut to prepare adhesion test pieces of a predetermined size. Next, to evaluate the adhesiveness, the copper-clad laminate of the adhesive test piece was peeled from the copper foil at 23°C and a pulling rate of 50 mm / min according to JIS C 6481 "Test Methods for Copper-Clad Laminates for Printed Wiring Boards," and the 180° peel adhesive strength (N / mm) was measured. The width of the adhesive test piece was 10 mm.

[0085] When an acid-modified styrene-based elastomer was used as the modified thermoplastic resin (A), if the 180° peel strength of the adhesive test piece was 1.0 N / mm or more, it was determined that sufficient adhesive strength could be developed in a short heat treatment time.If the 180° peel strength of the adhesive test piece was less than 0.6 N / mm, it was determined that sufficient adhesive strength could not be developed in a short heat treatment time.

[0086] On the other hand, when an acid-modified polyolefin resin was used as the modified thermoplastic resin (A), if the 180° peel strength of the adhesive test piece was 0.8 N / mm or more, it was determined that sufficient adhesive strength could be developed in a short heat treatment time. If the 180° peel strength of the adhesive test piece was less than 1.2 N / mm, it was determined that sufficient adhesive strength could not be developed in a short heat treatment time.

[0087] (5) Solder heat resistance of the cured adhesive composition The test was conducted in accordance with JIS C 6481, "Test Methods for Copper-Clad Laminates for Printed Wiring Boards," under the following conditions. Each adhesive test specimen was cut into 25 mm squares and heated at 120°C for 30 minutes. The specimen was then placed face up in a solder bath at a specified temperature for 10 seconds, and the foaming state on the surface of the adhesive test specimen was observed. The adhesive test specimen was then removed from the solder bath, allowed to stand at room temperature for 10 seconds, and then again floated in the solder bath at a specified temperature for 10 seconds. The foaming state on the surface of the adhesive test specimen was observed. The number of times the adhesive test specimen was floated in the solder bath was counted, and this procedure was repeated up to three times. The upper limit of the temperature at which no foaming was observed on the adhesive test specimen was defined as the solder heat resistance temperature (solder heat resistance temperature).

[0088] (6) Dielectric properties (dielectric constant) of the cured adhesive composition A 38 μm-thick release PET film was prepared, and the liquid adhesive composition listed in Tables 1 to 3 was applied to its release-treated surface. The coated film was then placed in an oven and dried at 90°C for 3 minutes to form a 50 μm-thick coating (adhesive layer), yielding an adhesive layer. The adhesive layer was then placed in an oven and cured at 190°C for 30 minutes. The release film was then peeled off to obtain a test piece (100 mm × 80 mm) made of the cured adhesive composition. The dielectric constants (Dk, εr) were measured using a network analyzer 85071E-300 (Agilent Technologies) by the split post dielectric resonator (SPDR) method at a temperature of 23°C and a frequency of 1 GHz.

[0089] 2. Raw materials for adhesive compositions The following raw materials for the adhesive composition were prepared. (1) Modified thermoplastic resin (A) Acid-modified styrene-based elastomer (a1) (manufactured by Asahi Kasei Chemicals Corporation, "Tuftec M1913", maleic anhydride-modified SEBS, acid value: 10 mg KOH / g, weight-average molecular weight Mw = 150,000) Acid-modified styrene-based elastomer (a2) (manufactured by Asahi Kasei Chemicals Corporation, "Tuftec M1911", maleic anhydride-modified SEBS, acid value: 2 mg KOH / g, weight-average molecular weight Mw = 150,000) Acid-modified polyolefin resin (a3) Acid-modified polyolefin resin (a3) ​​was prepared by the following method. 100 parts by mass of propylene / 1-butene copolymer (mass ratio: propylene / 1-butene = 70 / 30) was heated and melted in a four-neck flask under a nitrogen atmosphere. Then, while maintaining the internal temperature at 170°C and stirring, 3.0 parts by mass of maleic anhydride as an unsaturated carboxylic acid and 2.5 parts by mass of dicumyl peroxide as a radical generator were added over 1 hour, and the reaction was continued for 1 hour. After the reaction was completed, the resulting reaction product was poured into a large amount of acetone to solidify the resin. The resin was then finely chopped and processed into pellets. The pelletized resin was then mixed with acetone in an amount three times the mass of the resin and stirred at 50°C for 1 hour to wash the resin. The resin was then recovered and washed in the same manner to remove free maleic anhydride. The washed resin was then dried under reduced pressure in a vacuum dryer to obtain an acid-modified polyolefin resin (a3) ​​consisting of an acid-modified propylene / 1-butene copolymer. The resulting acid-modified polyolefin resin (a3) ​​had a weight average molecular weight Mw of 100,000 and an acid value of 30 mgKOH / g.

[0090] (2) Epoxy resin (B) Dicyclopentadiene skeleton-containing epoxy resin (DCPD-type epoxy resin) (b1) (DIC Corporation, "EPICLON HP-7200") Cresol novolac epoxy resin (DCPD epoxy resin) (b2) (DIC Corporation, "EPICLON N-655EXP")

[0091] (3) Curing accelerator (C) Imidazole-based curing accelerator (Shikoku Chemicals Corporation, "Curesol C11Z")

[0092] (4) Metal deactivator (D) Hydrazide skeleton-containing metal deactivator (ADEKA, "CDA-6S") Metal deactivator containing a hydrazide skeleton and a hindered phenol skeleton (ADEKA Corporation, "CDA-10")

[0093] (5) Other Styrene-based elastomer (unmodified) (Asahi Kasei Chemicals Corporation, "Tuftec H1041", SEBS, weight-average molecular weight Mw = 150,000)

[0094] The solvent used was a mixed solvent of toluene and methyl ethyl ketone (mass ratio = 90:10).

[0095] 3. Preparation and Evaluation of Adhesive Compositions The above raw materials were added to a 1000 ml flask equipped with a stirrer in the prescribed proportions shown in Tables 1 to 3, and a solvent was added. The mixture was stirred at room temperature (25°C) for 6 hours to dissolve the raw materials, and each adhesive composition was prepared and evaluated. The results are shown in Tables 1 to 3.

[0096] 4. Production and evaluation of laminates with adhesive layers Using the above adhesive composition, a laminate with an adhesive layer was produced and evaluated as described in the explanation for each evaluation method above. The results are shown in Tables 1 to 3.

[0097] [Table 1]

[0098] [Table 2]

[0099] [Table 3]

[0100] As shown in Tables 1 to 3, Samples 1 to 11 and Samples 1C to 4C are examples in which an acid-modified styrene-based elastomer was used as the modified thermoplastic resin (A), and Samples 12, 13, and Samples 5C to 8C are examples in which an acid-modified polyolefin-based resin was used as the modified thermoplastic resin (A).

[0101] Tables 1 to 3 reveal the following: Although the adhesive composition of Sample 1C contains all of the components (A), (B), (C), and (D), the content of the curing accelerator (C) is below the lower limit specified in the present disclosure. Therefore, Sample 1C did not achieve a sufficient increase in gel fraction after curing, and was unable to develop sufficient adhesive strength with a short heat treatment time.

[0102] Although the adhesive composition of Sample 2C contains all of the components (A), (B), (C), and (D), the content of the curing accelerator (C) exceeds the upper limit specified in this disclosure. As a result, Sample 2C had an excessively large gel fraction after curing, and was unable to develop sufficient adhesive strength even with a short heat treatment time.

[0103] Although the adhesive composition of Sample 3C contains all of the components (A), (B), (C), and (D), the content of epoxy resin (B) exceeds the upper limit specified in this disclosure. As a result, Sample 3C had an excessively large gel fraction after curing, and was unable to develop sufficient adhesive strength even with a short heat treatment time.

[0104] The adhesive composition of Sample 4C did not contain the curing accelerator (C), and therefore Sample 4C had an excessively small gel fraction after curing, and was unable to develop sufficient adhesive strength with a short heat treatment time.

[0105] The adhesive composition of Sample 5C did not contain the metal deactivator (D), and therefore Sample 5C was unable to develop sufficient adhesive strength in a short heat treatment time.

[0106] In Sample 6C, the adhesive composition contained all of the components (A), (B), (C), and (D), but the content of the curing accelerator (C) was below the lower limit specified in the present disclosure. As a result, Sample 6C was unable to develop sufficient adhesive strength and also had insufficient heat resistance.

[0107] Although the adhesive composition of Sample 7C contained all of the components (A), (B), (C), and (D), the content of the curing accelerator (C) exceeded the upper limit specified in this disclosure, and therefore Sample 7C failed to develop sufficient adhesive strength due to excessive reaction.

[0108] Sample 8C was prepared by curing Sample 5C for 30 minutes at 190°C, but the adhesive composition did not contain the metal deactivator (D). Like Sample 5C, Sample 8C was also unable to develop sufficient adhesive strength after a short heat treatment time.

[0109] In contrast, Samples 1 to 13 satisfy the requirements defined in the present disclosure, and therefore Samples 1 to 13 were able to develop sufficient adhesive strength with a short heat treatment time.

[0110] Furthermore, Sample 10 is an example in which an acid-modified styrene-based elastomer was used as the modified thermoplastic resin (A), and when the content of the metal deactivator (D) was less than 0.03 parts by mass per 100 parts by mass of the solids content of the adhesive composition, the gel fraction became smaller when cured for 30 minutes at 190°C, and there was a tendency for the adhesive strength and heat resistance to decrease. Therefore, it is clear that the content of the metal deactivator (D) is preferably 0.03 parts by mass or more per 100 parts by mass of the solids content of the adhesive composition.

[0111] In addition, Sample 11 is an example in which an acid-modified styrene-based elastomer was used as the modified thermoplastic resin (A), and when the content of the metal deactivator (D) exceeded 2 parts by mass per 100 parts by mass of the solid content of the adhesive composition, the gel fraction increased when cured for 30 minutes at 190°C, and the adhesive strength tended to decrease. Therefore, it is clear that the content of the metal deactivator (D) is preferably 2 parts by mass or less per 100 parts by mass of the solid content of the adhesive composition.

[0112] The present invention is not limited to the above-described embodiments and examples, and various modifications are possible without departing from the spirit of the present invention. Furthermore, the configurations shown in the above-described embodiments and examples can be combined in any manner.

Claims

1. A modified thermoplastic resin (A) having reactive functional groups that react with epoxy groups, an epoxy resin (B); a curing accelerator (C); An adhesive composition containing a metal deactivator (D), The content of the modified thermoplastic resin (A) is 50 parts by mass or more per 100 parts by mass of the solid content of the adhesive composition. The content of the epoxy resin (B) is 1 part by mass or more and 20 parts by mass or less per 100 parts by mass of the modified thermoplastic resin (A), The content of the curing accelerator (C) is 0.15 parts by mass or more and 9 parts by mass or less per 100 parts by mass of the epoxy resin (B). Adhesive composition.

2. The modified thermoplastic resin (A) is a resin in which an unmodified thermoplastic resin has been graft-modified with a modifying agent containing an α,β-unsaturated carboxylic acid or a derivative thereof. The adhesive composition of claim 1.

3. The aforementioned unmodified thermoplastic resin is at least one selected from the group consisting of styrene elastomers, ethylene-propylene copolymers, propylene-butene copolymers, and ethylene-propylene-butene copolymers. The adhesive composition of claim 2.

4. The aforementioned unmodified thermoplastic resin is a styrene-based elastomer. The adhesive composition has a gel fraction of 45% to 91% when cured at 190°C for 30 minutes. The adhesive composition of claim 2.

5. The curing accelerator (C) is at least one selected from the group consisting of tertiary amine curing accelerators, tertiary amine salt curing accelerators, and imidazole curing accelerators. The adhesive composition of claim 1.

6. The metal deactivator (D) contains at least one skeleton selected from the group consisting of a hydrazide skeleton, a triazine skeleton, and a hindered phenol skeleton. The adhesive composition of claim 1.

7. The content of the metal deactivator (D) is 0.03 parts by mass or more and 2 parts by mass or less per 100 parts by mass of solid content of the adhesive composition. The adhesive composition of claim 1.

8. A laminate with an adhesive layer comprising an adhesive layer formed from the adhesive composition according to any one of claims 1 to 7, and a base film in contact with at least one surface of the adhesive layer.

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