adhesive composition

Abstract

To provide an adhesive composition that is excellent in low dielectric properties and adhesion to an LCP.SOLUTION: As a result of extensive studies, the inventors have discovered that an adhesive composition comprising (A) an acid-modified styrenic elastomer, (B) an isocyanate compound having two or more isocyanate groups in one molecule and (C) an ethylene-propylene-diene copolymer at a specific ratio is excellent in low dielectric properties and also excellent in adhesion to a low polar substrate, particularly an LCP, which can solve the foregoing problem.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an adhesive composition that has low dielectric properties (low dielectric constant, low dielectric loss tangent) and excellent adhesion, and is suitable for producing electronic components, particularly components related to flexible printed circuit boards (hereinafter referred to as FPCs). [Background technology]

[0002] In recent years, advances in wireless communication technology for smartphones, mobile PCs, and other devices have created a demand for high-speed processing of large volumes of information, leading to the increasing frequency of transmission signals. As frequencies increase, FPCs and their related components, which are components of wireless communication devices, are also required to have low dielectric properties (low dielectric constant, low dielectric loss tangent) in the high-frequency band (see, for example, Patent Document 1).

[0003] As an FPC-related component having such excellent low dielectric properties, for example, a laminate formed by laminating a resin film and an adhesive layer made of an adhesive composition containing an acid-modified styrene-based elastomer and a polyisocyanate component is known to have excellent low dielectric properties (Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2016 / 017473 Brochure [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-163131 Summary of the Invention [Problem to be solved by the invention]

[0005] However, although LCP, which is used as the material for the resin film in the above laminate, has excellent low dielectric properties, it has low polarity and is a poorly adhesive material. Therefore, the adhesive composition specifically described in Patent Document 2 does not provide sufficient adhesive strength, and it has sometimes been difficult to produce FPC-related components such as coverlay films and laminates.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an adhesive composition that has low dielectric properties and excellent adhesion to LCP. [Means for solving the problem]

[0007] As a result of extensive research aimed at solving the above problems, the present inventors have found that the above problems can be solved by an adhesive composition containing (A) an acid-modified styrene-based elastomer, (B) an isocyanate compound having two or more isocyanate groups per molecule, and (C) an ethylene-propylene-diene copolymer in specific proportions. Specifically, the present invention includes the following inventions.

[0008] [1] (A) an acid-modified styrene-based elastomer, (B) an isocyanate compound having two or more isocyanate groups in one molecule, and (C) an ethylene-propylene-diene copolymer, the molar ratio (total isocyanate groups / total acidic groups) of the total acidic groups in (A) the acid-modified styrene elastomer to the total isocyanate groups in (B) the isocyanate compound having two or more isocyanate groups per molecule is 0.3 to 3.0, An adhesive composition in which the content of (C) is 5 to 80 parts by weight per 100 parts by weight of (A).

[0009] [2] 2. The adhesive composition according to claim 1, wherein (A) is at least one styrene-based elastomer selected from the group consisting of styrene-ethylenebutylene-styrene block copolymers and styrene-ethylenepropylene block copolymers, modified with an unsaturated carboxylic acid.

[0010] [3] The adhesive composition according to [1] or [2], wherein (B) is at least one isocyanate compound selected from the group consisting of aliphatic polyisocyanates, alicyclic polyisocyanates, and derivatives thereof.

[0011] [4] The adhesive composition according to any one of [1] to [3], wherein the (C) is an ethylene-propylene-diene copolymer in which the diene is dicyclopentadiene and / or ethylidene norbornene.

[0012] [5] The adhesive composition according to any one of [1] to [4], further comprising (D) a crosslinking agent.

[0013] [6] The adhesive composition according to any one of [1] to [5], further comprising (E) an organic solvent.

[0014] [7] An adhesive film obtained by using the adhesive composition according to any one of [1] to [6]. [Effects of the Invention]

[0015] The adhesive composition of the present invention has excellent low dielectric properties and excellent adhesion to low-polarity substrates, particularly LCP, and is therefore suitable for use in FPC-related components such as laminates with adhesive layers (coverlay films, bonding sheets), resin-coated copper foils, flexible copper-clad laminates, and flexible flat cables. DETAILED DESCRIPTION OF THE INVENTION

[0016] The present invention will be described in detail below. Note that the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present invention.

[0017] <Adhesive composition of the present invention> The adhesive composition of the present invention contains (A) an acid-modified styrene-based elastomer, (B) an isocyanate compound having two or more isocyanate groups per molecule, and (C) an ethylene-propylene-diene copolymer in specific proportions. The components (A) to (C) are described in detail below.

[0018] [(A) Acid-modified styrene-based elastomer] The acid-modified styrene elastomer in the present invention is an elastomer obtained by modifying a styrene elastomer with at least one selected from the group consisting of unsaturated carboxylic acids and unsaturated carboxylic anhydrides. Examples of methods for modifying a styrene elastomer include a method of subjecting a styrene elastomer to a graft reaction with at least one selected from the group consisting of unsaturated carboxylic acids and unsaturated carboxylic anhydrides.

[0019] Specific examples of styrene-based elastomers include styrene-butadiene block copolymer, styrene-ethylene propylene block copolymer, styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene block copolymer (SIS), styrene-ethylenebutylene-styrene block copolymer (SEBS), styrene-ethylenepropylene-styrene block copolymer (SEPS), etc. Among these styrene-based elastomers, styrene-ethylenebutylene-styrene block copolymer (SEBS) and styrene-ethylenepropylene-styrene block copolymer (SEPS) are preferred from the viewpoints of adhesiveness and low dielectric properties.

[0020] Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, itaconic acid, and fumaric acid. Examples of unsaturated carboxylic acid anhydrides include maleic anhydride, itaconic anhydride, and fumaric anhydride. Among these unsaturated carboxylic acids and unsaturated carboxylic acid anhydrides, maleic acid, fumaric acid, and maleic anhydride are preferred, with maleic anhydride being more preferred. The amount of modification with at least one selected from the group consisting of unsaturated carboxylic acids and unsaturated carboxylic acid anhydrides is typically about 0.1 to 10% by weight of the entire acid-modified styrene-based elastomer. Furthermore, it is preferred that at least a portion of the total acidic groups in the acid-modified styrene-based elastomer be acid anhydrides.

[0021] The acid value of the acid-modified styrene-based elastomer is, for example, 0.1 mg CH3ONa / g or more, preferably 0.5 mg CH3ONa / g or more, more preferably 1.0 mg CH3ONa / g or more, and for example, 20 mg CH3ONa / g or less, preferably 18 mg CH3ONa / g or less, more preferably 15 mg CH3ONa / g or less.

[0022] The molecular weight of the acid-modified styrene-based elastomer is, for example, a weight-average molecular weight of 10,000 or more, preferably 30,000 or more, more preferably 50,000 or more, and for example, 500,000 or less, preferably 300,000 or less, more preferably 200,000 or less. The weight-average molecular weight in the present invention is a molecular weight measured by gel permeation chromatography (GPC) in terms of polystyrene.

[0023] Examples of commercially available acid-modified styrene elastomers include the Tuftec M series manufactured by Asahi Kasei Corporation and the Kraton FG series manufactured by Kraton Polymer Japan.

[0024] In the present invention, the above-mentioned acid-modified styrene elastomers may be used alone or in combination of two or more kinds.

[0025] [(B) Isocyanate compound having two or more isocyanate groups in one molecule] Examples of the isocyanate compound having two or more isocyanate groups per molecule in the present invention (hereinafter, sometimes referred to as a polyisocyanate compound) include aromatic polyisocyanates, aliphatic polyisocyanates, araliphatic polyisocyanates, alicyclic polyisocyanates, and derivatives thereof. Examples of aromatic polyisocyanates include aromatic diisocyanates such as 1,3-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,4-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-toluidine diisocyanate, dianisidine diisocyanate, and 4,4'-diphenyl ether diisocyanate, and aromatic triisocyanates such as 2,4,6-triisocyanate toluene and 1,3,5-triisocyanate benzene. Examples of the aliphatic polyisocyanate include aliphatic diisocyanates such as trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate; and aliphatic triisocyanates such as lysine triisocyanate. Examples of the aromatic aliphatic polyisocyanate include aromatic aliphatic diisocyanates such as ω,ω'-diisocyanate-1,3-dimethylbenzene, ω,ω'-diisocyanate-1,4-dimethylbenzene, ω,ω'-diisocyanate-1,4-diethylbenzene, 1,4-tetramethylxylylene diisocyanate, and 1,3-tetramethylxylylene diisocyanate; and aromatic aliphatic triisocyanates such as 4,4',4"-triphenylmethane triisocyanate.Examples of alicyclic polyisocyanates include alicyclic diisocyanates such as 3-isocyanatemethyl-3,5,5-trimethylcyclohexyl isocyanate [also known as isophorone diisocyanate], 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), 1,3-bis(isocyanatemethyl)cyclohexane, and 1,4-bis(isocyanatemethyl)cyclohexane.

[0026] Examples of derivatives of polyisocyanate compounds include polymers of the above-mentioned polyisocyanate compounds (e.g., dimers, trimers (e.g., isocyanurate derivatives), etc.), allophanate derivatives, biuret derivatives, uretdione derivatives, and urethane prepolymers obtained by reacting a diisocyanate compound with a low-molecular-weight polyol or polyamine so that the terminal isocyanate groups.

[0027] Alternatively, a blocked isocyanate may be used in which at least a portion of the isocyanate groups of a polyisocyanate compound are blocked with a blocking agent. Specific examples include isocyanate compounds in which the isocyanate groups are blocked with ε-caprolactam, MEK (methyl ethyl ketone) oxime, cyclohexanone oxime, pyrazole, phenol, or the like.

[0028] Among these polyisocyanate compounds, aliphatic polyisocyanates, alicyclic polyisocyanates, and derivatives thereof are preferred, aliphatic diisocyanates, alicyclic diisocyanates, and trimers thereof are more preferred, and 1,3-bis(isocyanatemethyl)cyclohexane and trimers of hexamethylene diisocyanate are particularly preferred.

[0029] Commercially available polyisocyanate compounds include TrixeneBI7982, TrixeneBI7951, TrixeneBI7961, and TrixeneBI7991 manufactured by Baxenden Co., Ltd., Takenate B-820NP manufactured by Mitsui Chemicals, Inc., and VESTAGONB1530 and VESTAGONBF1540 manufactured by Evonik Co., Ltd. In the present invention, the above-mentioned polyisocyanate compounds may be used alone or in combination of two or more.

[0030] The content of (B) isocyanate compound having two or more isocyanate groups per molecule in the adhesive composition of the present invention is an amount such that the molar ratio (total isocyanate groups / total acidic groups) of the total acidic groups in (A) acid-modified styrene-based elastomer to the total isocyanate groups in (B) isocyanate compound having two or more isocyanate groups per molecule is usually 0.3 to 3.0, preferably 0.5 to 2.5, and more preferably 0.5 to 2.0. The total amount of acidic groups (mol) in the acid-modified styrene-based elastomer is calculated by dividing the acid value (mg CH3ONa / g) of the acid-modified styrene-based elastomer by the molecular weight of CH3ONa (sodium methoxide), and then multiplying by 10. 3 The total number of isocyanate groups in the isocyanate compound can be determined by dividing the amount (g) of the isocyanate compound in the adhesive composition by the isocyanate equivalent (g / mol) determined by a standard method.

[0031] [(C) Ethylene-propylene-diene copolymer] Ethylene-propylene-diene copolymers are also generally called EPDM (ethylene propylene diene rubber). Examples of the ethylene-propylene-diene copolymers of the present invention include ethylene-propylene-diene copolymers in which the diene is at least one selected from the group consisting of dicyclopentadiene (DCP), ethylidene norbornene (ENB), and 1,4-hexadiene (HD). Among these ethylene-propylene-diene copolymers, ethylene-propylene-diene copolymers in which the diene is dicyclopentadiene and / or ethylidene norbornene are preferred. Furthermore, the ethylene-propylene-diene copolymer is preferably liquid at room temperature (25°C).

[0032] Commercially available ethylene-propylene-diene copolymers include, for example, TRILENE 65, TRILENE 66, and TRILENE 77 manufactured by GSI Creos, and EPT manufactured by Mitsui Chemicals.

[0033] The amount of the ethylene-propylene-diene copolymer contained in the adhesive composition of the present invention is usually 5 to 80 parts by weight, preferably 10 to 60 parts by weight, per 100 parts by weight of the acid-modified styrene-based elastomer (A). In the present invention, the above-mentioned ethylene-propylene-diene copolymers may be used alone or in combination of two or more kinds.

[0034] [(D) Crosslinking agent] The adhesive composition of the present invention preferably further contains a crosslinking agent. Examples of crosslinking agents that can be used include those commonly used for crosslinking ethylene-propylene-diene copolymers, such as organic peroxides, sulfur, quinoids, bismaleimides, and phenolic resins. Examples of organic peroxides include tert-butyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)-3-hexyne, tert-butylcumyl peroxide, 1,3-di[(tert-butylperoxy)isopropyl]benzene, 1,4-di[(tert-butylperoxy)isopropyl]benzene, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, peroxyketals, and peroxyesters.

[0035] Examples of peroxyketals include n-butyl-4,4-di(tert-butylperoxy)valerate, 2,21-di(tert-butylperoxy)butane, 2,2-di[4,4-di(tert-butylperoxy)cyclohexyl]propane, 1,1-di(tert-butylperoxy)cyclohexane, di(3,5,5-trimethylhexanoyl)peroxide, 1,1-di(tert-hexylperoxy)cyclohexane, 1,1-di(tert-hexylperoxy)-3,3,5-trimethylcyclohexane, and 1,1-di(tert-butylperoxy)-2-methylcyclohexane.

[0036] Examples of peroxyesters include tert-butyl peroxybenzoate, tert-butyl peroxyacetate, tert-hexyl peroxybenzoate, tert-butylperoxy-2-ethylhexyl monocarbonate, tert-butyl peroxylaurate, tert-butylperoxyisopropyl carbonate, tert-butylperoxy-3,5,5-trimethylhexanoate, tert-butylperoxymaleic acid, and tert-hexylperoxyisopropyl carbonate.

[0037] Commercially available organic peroxides include, for example, Perbutyl P, Perbutyl H, Percumyl H, Percumyl P, Permenta H, and Perocta H, all manufactured by NOF Corp. In the present invention, the above organic peroxides may be used alone or in combination of two or more.

[0038] When a crosslinking agent is contained, the content thereof is, for example, 0.5 to 150 parts by weight, and preferably 2.0 to 50 parts by weight, relative to 100 parts by weight of the ethylene-propylene-diene copolymer (C).

[0039] [Other ingredients] In addition to the above components (A) to (D), the adhesive composition of the present invention may contain other thermoplastic resins other than the (A) acid-modified styrene-based elastomer and the (C) ethylene-propylene-diene copolymer, a curing accelerator, a tackifier, a flame retardant, a coupling agent, an antioxidant, a filler, and (E) an organic solvent.

[0040] Examples of the other thermoplastic resins include styrene elastomers other than the (A) acid-modified styrene elastomer, phenoxy resins, polyamide resins, polyester resins, polycarbonate resins, polyphenylene oxide resins, polyurethane resins, polyacetal resins, polyethylene resins, polypropylene resins, and polyvinyl resins. These thermoplastic resins may be used alone or in combination of two or more.

[0041] Examples of the curing accelerator include amines such as triethylamine, lutidine, picoline, and DBU (1,8-diazabicyclo[5.4.0]-7-undecene), alkali metal and alkaline earth metal compounds such as lithium methylate, sodium methylate, sodium ethylate, potassium butoxide, potassium fluoride, and sodium fluoride, and metal and semimetal compounds such as titanium, cobalt, tin, zinc, and aluminum. These curing accelerators may be used alone or in combination of two or more.

[0042] Examples of the tackifier include coumarone-indene resin, terpene resin, terpene-phenol resin, rosin resin, pt-butylphenol-acetylene resin, phenol-formaldehyde resin, xylene-formaldehyde resin, petroleum-based hydrocarbon resin, hydrogenated hydrocarbon resin, turpentine-based resin, etc. These tackifiers may be used alone or in combination of two or more.

[0043] Examples of the flame retardant include organic flame retardants and inorganic flame retardants. 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 melamine, melam, and melamine cyanurate; cyanuric acid compounds, isocyanuric acid compounds, triazole 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.

[0044] 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-isocyanatopropyltriethoxysilane, and imidazole silane, 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.

[0045] Examples of the antioxidant 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 glycol- Examples of antioxidants include phenol-based antioxidants such as 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.

[0046] Examples of the filler include fluorine-based polymer fine particles, olefin-based polymer fine particles, polyacrylic ester powder, epoxy resin powder, polyamide powder, polyurethane powder, and polysiloxane powder, as well as polymer fillers such as multilayer core-shell fillers using silicone, acrylic, styrene-butadiene rubber, and butadiene rubber, and inorganic fillers such as silica, mica, talc, kaolin, clay, hydrotalcite, wollastonite, xonotlite, silicon nitride, boron nitride, aluminum nitride, calcium hydrogen phosphate, calcium phosphate, glass flakes, hydrated glass, calcium titanate, sepiolite, magnesium sulfate, aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, barium hydroxide, calcium hydroxide, titanium oxide, tin oxide, aluminum oxide, magnesium oxide, zirconium oxide, zinc oxide, molybdenum oxide, antimony oxide, nickel oxide, zinc carbonate, magnesium carbonate, calcium carbonate, barium carbonate, zinc borate, and aluminum borate. These fillers may be used alone or in combination of two or more. The shape may be, for example, spherical, powdery, fibrous, needle-like, or scaly.

[0047] Examples of the organic solvent (E) include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, cyclohexane, methylcyclohexane, toluene, xylene, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, ethylene glycol monomethyl ether acetate, propylene glycol dimethyl ether, benzenedioxane, cyclopentyl methyl ether, methylene chloride, chloroform, 1,2-dichloroethane, γ-butyrolactone, cellosolve, butyl cellosolve, carbitol, butyl carbitol, etc. These solvents may be used alone or in combination of two or more.

[0048] In addition to the other components described above, the adhesive composition of the present invention may also contain, for example, stabilizers such as light resistance stabilizers, weather resistance stabilizers, and heat stabilizers, leveling agents, antifoaming agents and other anionic, cationic, and nonionic surfactants, dyes, pigments, plasticizers, and the like.

[0049] The adhesive composition of the present invention can be produced by mixing (A) an acid-modified styrene-based elastomer, (B) an isocyanate compound having two or more isocyanate groups per molecule, (C) an ethylene-propylene-diene copolymer, 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 in which fine particles are dispersed (hereinafter referred to as a liquid adhesive composition), an organic solvent (E) is also typically used. By using a liquid adhesive composition, coating of the substrate and formation of an adhesive layer can be carried out more smoothly when producing FPC-related components, making it easier to obtain an adhesive layer of the desired thickness.

[0050] When the adhesive composition is in a liquid form, the solid content concentration is, for example, 3 to 80% by weight, and preferably 10 to 50% by weight, from the viewpoint of workability including the formation of the adhesive layer.

[0051] [Characteristics of adhesive composition] The cured product obtained by curing the adhesive composition of the present invention has excellent low dielectric properties. The dielectric constant of the cured adhesive composition is usually less than 2.40, preferably less than 2.30. The dielectric loss tangent is usually less than 0.002, preferably less than 0.001.

[0052] These properties of the adhesive composition of the present invention are measured by the methods described in the Examples section below.

[0053] [Application] The adhesive composition of the present invention has excellent low dielectric properties and excellent adhesion to low-polarity substrates, particularly LCP, and can therefore be suitably used as an adhesive (e.g., adhesive film) for producing FPC-related components. Examples of FPC-related components of the present invention include coverlay films, bonding sheets, resin-coated copper foils, flexible copper-clad laminates, and flexible flat cables. [Example]

[0054] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these. In the following examples, the adhesive layer being in a B-stage state refers to a semi-cured state in which a portion of the adhesive composition has begun to harden, and the curing of the adhesive composition will proceed further by heating or the like.

[0055] Examples 1 to 9 The components were added to a 1000 ml flask equipped with a stirrer in the proportions (parts by weight) shown in Table 1, and mixed by stirring at 25°C for 6 hours to prepare an adhesive composition. Using the resulting adhesive composition, various physical properties were measured and evaluated using the methods described below. The results are shown in Table 1. The molar ratio was calculated from (total isocyanate groups / total acidic groups).

[0056] (Comparative Examples 1 to 4) The components were added to a 1000 ml flask equipped with a stirrer in the proportions (parts by weight) shown in Table 2, and mixed by stirring at 25°C for 6 hours to prepare an adhesive composition. Using the resulting adhesive composition, various physical properties were measured and evaluated using the methods described below. The results are shown in Table 2. The molar ratio was calculated from (total isocyanate groups / total acidic groups).

[0057] (1) Dielectric constant and dielectric loss tangent A release-treated glass plate was prepared, and one surface thereof was coated with the adhesive composition described in Tables 1 and 2 to a dry thickness of 100 μm. The coated film was then placed in an oven and dried at 100°C for 10 minutes to form a B-stage adhesive layer (100 μm thick). This adhesive layer was then placed in an oven and heat-cured at 160°C for 60 minutes to prepare a test specimen. The dielectric constant (Dk) and dielectric loss tangent (Df) of the prepared test specimen were measured using a dielectric constant measuring device manufactured by AET Corporation by the cavity resonator method at a measurement temperature of 25°C and a measurement frequency of 10 GHz.

[0058] (2) Peeling strength (90° peel strength) A 50 μm-thick LCP film ("Vexstar CTQ-50" manufactured by Kuraray Co., Ltd.) was prepared, and one surface thereof was coated with the adhesive composition listed in Tables 1 and 2. The coated film was then placed in an oven and dried at 100°C for 5 minutes to form a B-stage adhesive layer (approximately 15 μm thick), yielding a coverlay film. The same LCP film as above was then laminated to obtain a laminate in which two LCP films were bonded together via the adhesive composition. The laminate was then heated and pressed at 160°C and 4.5 MPa for 60 minutes, and then cut to a width of 10 mm and a length of 100 mm to prepare a sample for measuring the peel strength of the LCP film. The resulting measurement sample was measured for peel strength (90° peel strength, N / mm) in the 90° direction (the direction perpendicular to the surface direction of the laminate) using a Shimadzu Autograph AGS-500 at a test speed of 50 mm / min. Tables 1 and 2 show the ratio of the adhesive strength of each Example and Comparative Example when the adhesive strength of Comparative Example 1 is taken as 100% (the ratio, %) calculated by [peel adhesive strength of each Example and Comparative Example (N / mm)] / [peel adhesive strength of Comparative Example 1 (N / mm)]×100).

[0059] The components in Tables 1 and 2 are as follows: [(A): Acid-modified styrene-based elastomer] (A-1): Tuftec M1913 (Asahi Kasei Chemicals Corporation, maleic anhydride-modified styrene-ethylene butylene-styrene block copolymer, acid value: 10 mg CH3ONa / g, weight-average molecular weight: 150,000) (A-2): Tuftec M1911 (Asahi Kasei Chemicals Corporation, maleic anhydride-modified styrene-ethylene butylene-styrene block copolymer, acid value: 2 mg CH3ONa / g, weight-average molecular weight: 150,000)

[0060] [(B): Isocyanate compound having two or more isocyanate groups in one molecule] (B-1): Trixene BI7982 (manufactured by Baxenden, blocked hexamethylene diisocyanate trimer, solid content: 70% by weight, isocyanate equivalent (molecular weight per isocyanate group): 410 g / mol)

[0061] [(C): Ethylene-propylene-diene copolymer] (C-1): Trilene 65 (Liquid EPDM, manufactured by Lion Elastomers, diene: dicyclopentadiene) (C-2): Trilene 67 (Liquid EPDM, manufactured by Lion Elastomers, diene: ethylidene norbornene) (C-3): Trilene 77 (manufactured by Lion Elastomers, solid EPDM, diene: ethylidene norbornene)

[0062] [(D) Crosslinking agent] (D-1): Perbutyl P (NOF Corporation)

[0063] [(E): Organic solvent] (E-1): Toluene

[0064] [Table 1]

[0065] [Table 2]

Claims

1. (A) an acid-modified styrene-based elastomer, (B) an isocyanate compound having two or more isocyanate groups in one molecule, and (C) an ethylene-propylene-diene copolymer, the molar ratio (total isocyanate groups / total acidic groups) of the total acidic groups in (A) the acid-modified styrene-based elastomer to the total isocyanate groups in (B) the isocyanate compound having two or more isocyanate groups per molecule is 0.3 to 3.0, The content of (C) is 5 to 80 parts by weight per 100 parts by weight of (A). Adhesive composition.

2. 2. The adhesive composition according to claim 1, wherein (A) is at least one styrene-based elastomer selected from the group consisting of a styrene-ethylene butylene-styrene block copolymer and a styrene-ethylene propylene block copolymer, modified with an unsaturated carboxylic acid.

3. 3. The adhesive composition according to claim 1, wherein (B) is at least one isocyanate compound selected from the group consisting of aliphatic polyisocyanates, alicyclic polyisocyanates, and derivatives thereof.

4. 4. The adhesive composition according to claim 1, wherein the (C) is an ethylene-propylene-diene copolymer in which the diene is dicyclopentadiene and / or ethylidene norbornene.

5. The adhesive composition according to any one of claims 1 to 4, further comprising (D) a crosslinking agent.

6. The adhesive composition according to any one of claims 1 to 5, further comprising (E) an organic solvent.

7. An adhesive film obtained by using the adhesive composition according to any one of claims 1 to 6.

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