Adhesive composition

Abstract

To provide an adhesive composition that has sufficiently low dielectric properties and can sufficiently bond resin to metal.SOLUTION: The problem can be solved by an adhesive composition that comprises following components at a specific ratio: (A) an acid-modified styrenic elastomer, (B) an isocyanate compound having two or more isocyanate groups in one molecule, (C) fluorine-based polymer fine particles and (D) olefinic polymer fine particles, wherein the adhesive composition has sufficiently low dielectric properties and can sufficiently bond resin to metal.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an adhesive composition that is excellent in low dielectric properties (low dielectric constant, low dielectric tangent) and adhesiveness, and is suitable for manufacturing electronic components, particularly related members of a flexible printed wiring board (hereinafter, FPC).

Background Art

[0002] In recent years, with the progress of wireless communication technologies such as smartphones and mobile personal computers, it has been required to process a large amount of information at high speed, and the high-frequencyization of transmission signals has been progressing. Along with the high-frequencyization, low dielectric properties (low dielectric constant, low dielectric tangent) in the high-frequency band are also required for an FPC, which is one of the components of a wireless communication device, and its related members (for example, International Publication No. 2016 / 017473 (Patent Document 1)).

[0003] Further, as the related member, for example, when manufacturing an FPC, a laminate with an adhesive layer called a "coverlay film" is used to protect a wiring portion. The adhesive layer is also required to have strong adhesiveness to the wiring portion and the base film.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The present invention has been made in view of such circumstances, and an object thereof is to provide an adhesive composition that is excellent in low dielectric properties and adhesiveness between a resin and a metal.

Means for Solving the Problems

[0006] The present inventors, after diligent research to solve the above problems, have found that the above problems can be solved by an adhesive composition containing (A) an acid-modified styrene elastomer, (B) an isocyanate compound having two or more isocyanate groups in one molecule, (C) fluorine-based polymer fine particles, and (D) olefin-based polymer fine particles in a specific proportion. Specifically, the present invention includes the following inventions.

[0007] [1] (A) Acid-modified styrene elastomer, (B) Isocyanate compound having two or more isocyanate groups in one molecule, (C) Fluorine-based polymer fine particles, and (D) Olefin-based polymer fine particles are included. (A) The molar ratio of isocyanate groups in an isocyanate compound having two or more isocyanate groups per molecule to the total acidic groups in an acid-modified styrene elastomer (isocyanate groups / total acidic groups) is 0.3 to 3.0. (C) The content of fluorine polymer fine particles is 15 to 100 parts by weight per 100 parts by weight of (A) acid-modified styrene elastomer. (D) The content of olefin polymer fine particles is 7 to 55 parts by weight per 100 parts by weight of (A) acid-modified styrene elastomer. Adhesive composition.

[0008] [2] The adhesive composition according to [1], wherein the above (A) acid-modified styrene elastomer is obtained by modifying at least one styrene elastomer selected from the group consisting of styrene-ethylenebutylene-styrene block copolymer and styrene-ethylenepropylene block copolymer with at least one selected from the group consisting of unsaturated carboxylic acids and unsaturated carboxylic acid anhydrides.

[0009] [3] The adhesive composition according to [1], wherein the isocyanate compound having two or more isocyanate groups in one molecule of (B) is at least one compound selected from the group consisting of aliphatic polyisocyanates, alicyclic polyisocyanates, and derivatives thereof.

[0010] [4] The adhesive composition according to [1], wherein the above (C) fluorine-based polymer fine particles are fine particles composed of at least one fluorine-based polymer selected from the group consisting of polytetrafluoroethylene, fluorinated ethylene-propylene copolymer, perfluoroalkoxy polymer, tetrafluoroethylene-chlorotrifluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, and polychlorotrifluoroethylene.

[0011] [5] The adhesive composition according to [1], wherein the (D) olefin polymer fine particles are fine particles composed of at least one olefin polymer selected from the group consisting of polyethylene, polypropylene, and ethylene-propylene copolymer.

[0012] [6] Furthermore, an adhesive composition according to any one of [1] to [5], comprising (E) an organic solvent.

[0013] [7] An adhesive film made using an adhesive composition described in any one of items [1] to [5].

[0014] [8] An adhesive film made using the adhesive composition described in [6]. [Effects of the Invention]

[0015] The adhesive composition of the present invention exhibits excellent low dielectric properties and adhesion between resins and metals. Therefore, the adhesive composition of the present invention can be suitably used in applications such as laminates with adhesive layers (coverlay films, bonding sheets), resin-coated copper foil, flexible copper-clad laminates, and flexible flat cables. [Modes for carrying out 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 and implemented within the scope of the gist thereof.

[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 in one molecule, (C) fluoropolymer fine particles, and (D) olefin-based polymer fine particles. Hereinafter, the components (A) to (D) will be specifically described.

[0018] [(A) Acid-Modified Styrene-Based Elastomer] In the present invention, as a main component constituting the adhesive composition, a styrene-based elastomer (acid-modified styrene-based elastomer) modified with at least one selected from the group consisting of unsaturated carboxylic acids and unsaturated carboxylic acid anhydrides is used. Examples of the method for modifying the styrene-based elastomer include, for example, a method of subjecting the styrene-based elastomer to a graft reaction with at least one selected from the group consisting of unsaturated carboxylic acids and unsaturated carboxylic acid anhydrides.

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

[0020] Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, maleic acid, itaconic acid, fumaric acid, etc. Examples of the unsaturated carboxylic anhydride include maleic anhydride, itaconic anhydride, fumaric anhydride, etc. Among these unsaturated carboxylic acids and unsaturated carboxylic anhydrides, maleic acid, fumaric acid, and maleic anhydride are preferable, and maleic anhydride is more preferable. The amount of modification with at least one selected from the group consisting of unsaturated carboxylic acids and unsaturated carboxylic anhydrides is usually about 0.1 to 10% by weight of the whole acid-modified styrene-based elastomer. Further, in the acid-modified styrene-based elastomer, it is preferable that at least a part of all the acidic groups in the acid-modified elastomer is an acid anhydride.

[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 is, 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, 10,000 or more, preferably 30,000 or more, more preferably 50,000 or more in terms of weight average molecular weight, and is, 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 the molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

[0023] Examples of commercially available products of the acid-modified styrene-based elastomer include Tuftec M series manufactured by Asahi Kasei Corporation, and Clayton FG series manufactured by Clayton Polymer Japan Co., Ltd.

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

[0025] [(B) Isocyanate compound having two or more isocyanate groups in one molecule]Examples of isocyanate compounds having two or more isocyanate groups in one molecule in the present invention (hereinafter sometimes referred to as polyisocyanate compounds) include aromatic polyisocyanates, aliphatic polyisocyanates, aromatic aliphatic polyisocyanates, alicyclic polyisocyanates, and derivatives thereof. Examples of aromatic polyisocyanates include aromatic diisocyanates such as 1,3-phenylenediisocyanate, 4,4'-diphenyldiisocyanate, 1,4-phenylenediisocyanate, 4,4'-diphenylmethanediisocyanate, 2,4-tolylenediisocyanate, 2,6-tolylenediisocyanate, 4,4'-toluidinediisocyanate, dianisidinediisocyanate, and 4,4'-diphenyletherdiisocyanate, as well as aromatic triisocyanates such as 2,4,6-triisocyanatetoluene and 1,3,5-triisocyanatebenzene. Examples of aliphatic polyisocyanates 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, as well as aliphatic triisocyanates such as lysine triisocyanate. Examples of aromatic aliphatic polyisocyanates 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-tetramethylxylylenediisocyanate, and 1,3-tetramethylxylylenediisocyanate, as well as aromatic aliphatic triisocyanates such as 4,4',4''-triphenylmethanetriisocyanate.Examples of alicyclic polyisocyanates include 3-isocyanate methyl-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(isocyanate methyl)cyclohexane, 1,4-bis(isocyanate methyl)cyclohexane, and other alicyclic diisocyanates.

[0026] Examples of polyisocyanate compound derivatives 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 diisocyanate compounds with low molecular weight polyols or polyamines such that the terminal ends are isocyanates.

[0027] Furthermore, blocked isocyanates may be used in which at least a portion of the isocyanate groups of the polyisocyanate compound are blocked by 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, etc.

[0028] Among these isocyanate compounds having two or more isocyanate groups in one molecule, aliphatic polyisocyanates, alicyclic polyisocyanates and their derivatives are preferred, aliphatic diisocyanates, alicyclic diisocyanates and their trimers are more preferred, and trimers of 1,3-bis(isocyanatemethyl)cyclohexane and hexamethylene diisocyanate are particularly preferred.

[0029] Commercially available isocyanate compounds having two or more isocyanate groups in one molecule include TrixeneBI7982, TrixeneBI7951, TrixeneBI7961, and TrixeneBI7991 from Baxsenden, Takenate B-820NP from Mitsui Chemicals, and VESTAGON B1530 and VESTAGON BF1540 from Evonik. In the present invention, the above-mentioned isocyanate compounds may be used individually or in combination of two or more.

[0030] In the adhesive composition of the present invention, the molar ratio (isocyanate groups / total acidic groups) of isocyanate groups in (B) an isocyanate compound having two or more isocyanate groups per molecule to the total acidic groups in (A) an acid-modified styrene elastomer is usually 0.3 to 3.0, preferably 0.5 to 2.5, and more preferably 0.7 to 2.0. The total amount of acidic groups (mol) in the acid-modified styrene elastomer is calculated by dividing the acid value of the acid-modified styrene elastomer (mgCH3ONa / g) by the molecular weight of CH3ONa (sodium methoxide), and then further dividing by 10. 3 This can be determined by dividing by the total amount of acidic groups (mol / g) per gram of acid-modified styrene elastomer, and then multiplying this by the amount (g) of acid-modified styrene elastomer in the adhesive composition.

[0031] [(C) Fluorine-based polymer microparticles] The fluorine-based polymer fine particles in the present invention are fine particles mainly composed of fluorine-based polymers. Suitable fluorine-based polymers include, for example, polytetrafluoroethylene (PTFE), fluorinated ethylene-propylene copolymer (FEP), perfluoroalkoxy polymer (PFA), tetrafluoroethylene-chlorotrifluoroethylene copolymer (TFE / CTFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), and polychlorotrifluoroethylene (PCTFE). Among these fluorine-based polymers, polytetrafluoroethylene (PTFE) is preferred.

[0032] Examples of commercially available fluorine-based polymer microparticles include Fluo400XF from MicroPowders, Rubron L-5F from Daikin Industries, and SST-1MG from Shamrock.

[0033] Fluorine polymer fine particles may be composed of these fluorine polymers alone, or they may be composed of two or more types in combination. Furthermore, in the present invention, the above-mentioned fluorine polymer fine particles may be used alone, or two or more types with different compositions may be used in combination.

[0034] The average particle size of the fluorine-based polymer fine particles is preferably 10 μm or less, more preferably 7 μm or less, and even more preferably 5 μm or less, from the viewpoint of dispersibility and other factors. The average particle size is usually 0.1 μm or more.

[0035] The amount of fluorine polymer fine particles contained in the adhesive composition of the present invention is usually 15 to 100 parts by weight, preferably 20 to 80 parts by weight, per 100 parts by weight of (A) acid-modified styrene elastomer.

[0036] [(D) Olefin polymer microparticles] The olefin polymer fine particles in the present invention are fine particles mainly composed of an olefin polymer. Examples of olefin polymers include at least one polymer selected from the group consisting of olefins. Examples of olefins include ethylene, propylene, 1-butene, 4-methyl-1-pentene, etc. Specific examples of the at least one polymer selected from the group consisting of olefins include polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, ethylene-propylene copolymer, etc. Furthermore, the olefin polymer constituting the olefin polymer fine particles may be a copolymer of at least one polymer selected from the group consisting of olefins and a diene compound. Examples of diene compounds include butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, dicyclopentadiene, etc. Specific examples of copolymers of at least one polymer selected from the group consisting of olefins and a diene compound include ethylene-butadiene copolymer, ethylene-propylene-butadiene copolymer, ethylene-propylene-dicyclopentadiene copolymer, etc.

[0037] Among these olefin polymers, polyethylene, polypropylene, and ethylene-propylene copolymers are preferred.

[0038] The olefin polymer fine particles may be composed of these olefin polymers alone, or they may be composed of two or more in combination. They may also contain other thermoplastic resins other than olefin polymers.

[0039] Examples of commercially available olefin-based polymer microparticles include polyethylene microparticles such as MPP-635XF from MicroPowders, Flowbeads LE-1080 and Flowbeads HE-3040 from Sumitomo Seika Co., Ltd., and S-394N1 from Shamrock, Inc., and polypropylene microparticles such as Micropro500 from MicroPowders and S-363 from Shamrock, Inc. In the present invention, the above-mentioned olefin-based polymer microparticles may be used individually or in combination of two or more types with different compositions.

[0040] From the viewpoint of dispersibility and other factors, the average particle size of the olefin polymer fine particles is preferably 0.1 μm to 50 μm, more preferably 0.3 μm to 25 μm, and even more preferably 0.5 μm to 15 μm.

[0041] The melting point of the olefin polymer fine particles is preferably 70 to 160°C, more preferably 90 to 155°C, and even more preferably 100 to 150°C. Excellent adhesion can be achieved by keeping the melting point within this range.

[0042] The amount of olefin polymer fine particles contained in the adhesive composition of the present invention is usually 7 to 55 parts by weight, preferably 10 to 50 parts by weight, per 100 parts by weight of (A) acid-modified styrene elastomer.

[0043] [Other ingredients] In addition to the above components (A) to (D), the adhesive composition of the present invention may contain (A) other thermoplastic resins other than acid-modified styrene elastomers, curing accelerators, tackifiers, flame retardants, coupling agents, antioxidants, (C) other fillers other than fluorine-based polymer fine particles and (D) polyolefin-based polymer fine particles, and (E) organic solvents, etc.

[0044] Examples of the above-mentioned other thermoplastic resins include styrene-based elastomers that do not contain acid anhydride groups, phenoxy resins, polyamide resins, polyester resins, polycarbonate resins, polyphenylene oxide resins, polyurethane resins, polyacetal resins, polyethylene-based resins, polypropylene-based resins, and polyvinyl-based resins. These thermoplastic resins may be used individually or in combination of two or more types.

[0045] Examples of the curing accelerators mentioned above include amines such as triethylamine, lutidine, picoline, and DBU (1,8-diazabicyclo[5.4.0]-7-undecene), alkali metal compounds or alkaline earth metal compounds such as lithium methylate, sodium methylate, sodium ethylate, potassium butoxide, potassium fluoride, and sodium fluoride, and metals and metalloid compounds such as titanium, cobalt, tin, zinc, and aluminum. These curing accelerators may be used individually or in combination of two or more.

[0046] Examples of the tackifiers mentioned above include coumarone-indene resin, terpene resin, terpene-phenol resin, rosin resin, pt-butylphenol-acetylene resin, phenol-formaldehyde resin, xylene-formaldehyde resin, petroleum hydrocarbon resin, hydrogenated hydrocarbon resin, and turpentine resin. These tackifiers may be used individually or in combination of two or more.

[0047] Examples of the above-mentioned flame retardants 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 phosphate, ammonium polyphosphate, carbamate phosphate, carbamate polyphosphate, aluminum tris-diethylphosphinate, aluminum tris-methylethylphosphinate, aluminum tris-diphenylphosphinate, zinc bis-diethylphosphinate, zinc bis-methylethylphosphinate, zinc bis-diphenylphosphinate, titanyl bis-diethylphosphinate, titanium tetrakis-diethylphosphinate, titanyl bis-methylethylphosphinate, titanium tetrakis-methylethylphosphinate, titanyl bis-diphenylphosphinate, and titanium tetrakis-diphenylphosphinate; nitrogen-based flame retardants such as triazine compounds like melamine, melam, and melamine cyanurate, as well as 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; and zinc carbonate, magnesium carbonate, barium carbonate, zinc borate, and hydrated glass. These flame retardants may be used individually or in combination of two or more types.

[0048] Examples of the coupling agents mentioned above 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-isocyanatetopropyltriethoxysilane, 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.

[0049] Examples of the above antioxidants 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 include phenolic 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 may be used individually or in combination of two or more.

[0050] Other fillers mentioned above include, for example, polyacrylic acid ester powder, epoxy resin powder, polyamide powder, polyurethane powder, polysiloxane powder, and polymeric fillers such as multilayer core-shell structures 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 dioxide, 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 individually or in combination of two or more types. Furthermore, in terms of shape, for example, spherical, powdery, fibrous, needle-shaped, or flaky forms can be used.

[0051] Examples of the above (E) organic solvents 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, dioxane, cyclopentyl methyl ether, methylene chloride, chloroform, 1,2-dichloroethane, γ-butyrolactone, cellosolve, butyl cellosolve, carbitol, and butyl carbitol. These organic solvents may be used individually or in combination of two or more.

[0052] Furthermore, in addition to the other components mentioned above, the adhesive composition of the present invention may also contain, for example, stabilizers such as light stabilizers, weather stabilizers, and heat stabilizers; anionic, cationic, and nonionic surfactants such as leveling agents and defoamers; dyes; pigments; plasticizers; and the like.

[0053] The adhesive composition of the present invention can be manufactured by mixing (A) an acid-modified styrene elastomer, (B) an isocyanate compound having two or more isocyanate groups in one molecule, (C) fluorine-based polymer fine particles, (D) olefin-based polymer fine particles, and other components as needed. The mixing method is not particularly limited, as long as the adhesive composition becomes uniform. Since the adhesive composition is preferably used in a solution state in which fine particles are dispersed (hereinafter referred to as the liquid adhesive composition), the above (E) organic solvent is usually also used. By using a liquid adhesive composition, coating on the substrate and forming the adhesive layer can be performed more smoothly when manufacturing FPC-related components, and an adhesive layer of the desired thickness can be obtained more easily.

[0054] When the adhesive composition is liquid, the solid content concentration is, for example, 3 to 80% by weight, preferably 10 to 50% by weight, from the viewpoint of workability, including the formation of the adhesive layer.

[0055] [Properties of adhesive compositions] The cured product obtained by curing the adhesive composition of the present invention exhibits excellent low dielectric properties. The dielectric constant of the cured adhesive composition is usually less than 2.30, preferably less than 2.25. Furthermore, the dielectric loss tangent is usually less than 0.002, preferably less than 0.001.

[0056] The cured product obtained by curing the adhesive composition of the present invention exhibits excellent peel adhesion strength. The peel adhesion strength of the cured adhesive composition is typically 1.3 N / mm, preferably 1.5 N / mm, based on a 90° peel strength.

[0057] The properties of these adhesive compositions of the present invention are measured by the methods described in the Examples section below.

[0058] <Application> The adhesive composition of the present invention exhibits low dielectric properties and excellent adhesion between resin and metal, making it suitable for use as an adhesive (e.g., adhesive film, etc.) for manufacturing related components of FPCs. Examples of related components of FPCs in the present invention include coverlay film, bonding sheet, resin-coated copper foil, flexible copper-clad laminate, and flexible flat cable. [Examples]

[0059] 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 part of the adhesive composition has begun to harden, and the hardening of the adhesive composition will progress further due to heating or the like.

[0060] (Examples 1-10) An adhesive composition was prepared by adding each component in the proportions (parts by weight) shown in Table 1 to a 1000 ml flask equipped with a stirring device and stirring at room temperature for 6 hours to disperse the mixture. The physical properties of the obtained adhesive composition were measured and evaluated using the following method. The results are shown in Table 1. The molar ratio was calculated from (isocyanate group / total acidic group).

[0061] (Comparative Examples 1-7) An adhesive composition was prepared by adding each component in the proportions (parts by weight) shown in Table 2 to a 1000 ml flask equipped with a stirring device and stirring at room temperature for 6 hours to disperse the mixture. The physical properties of the obtained adhesive composition were measured and evaluated using the following method. The results are shown in Table 2. The molar ratio was calculated from (isocyanate group or epoxy group / total acidic group).

[0062] (1) Dielectric constant, dielectric loss tangent A glass plate that had been treated with a release agent was prepared, and the adhesive compositions described in Tables 1 and 2 were applied to one surface of the plate to a thickness of 100 μm after drying. Next, the coated glass plate was left in an oven and dried at 100°C for 10 minutes to form a B-stage adhesive layer (thickness 100 μm). Then, this adhesive layer was left in the oven and heat-cured at 160°C for 60 minutes to prepare a test specimen. For this test specimen, the dielectric constant (Dk) and dielectric loss tangent (Df) were determined using the cavity resonator method with a dielectric constant measuring device manufactured by AET Co., Ltd. at a measurement temperature of 25°C and a measurement frequency of 10 GHz. The evaluation criteria are as follows.

[0063] (dielectric constant) A... Dielectric constant is less than 2.25 B... Dielectric constant is 2.25 or higher and less than 2.30 C... Dielectric constant of 2.30 or higher

[0064] (Dielectric loss tangent) A... Dielectric loss tangent is less than 0.001 B... Dielectric loss tangent is 0.001 or greater and less than 0.002. C... Dielectric loss tangent is 0.002 or higher

[0065] (2) Peel bond strength A 25 μm thick polyimide film [Kapton 100EN, manufactured by Toray DuPont] was prepared, and the adhesive compositions described in Tables 1 and 2 were applied to one surface of the film. Next, the coated film was placed in an oven and dried at 100°C for 5 minutes to form a B-stage adhesive layer (approximately 15 μm thick), obtaining a coverlay film. Then, an 18 μm thick electrolytic copper foil was superimposed so as to be in surface contact with the adhesive layer of the coverlay film (polyimide film / adhesive layer / copper foil), and heated and pressed at 160°C and 4.5 MPa for 60 minutes to obtain a flexible copper-clad laminate. This flexible copper-clad laminate was cut to a width of 10 mm and a length of 100 mm, and the peel adhesion strength in the 90° direction (direction perpendicular to the surface direction of the laminate) was measured using a Shimadzu Autograph AGS-500 under the following measurement conditions. The test speed was set to 50 mm / min. The evaluation criteria are as follows. A... Peel adhesion strength of 1.5 N / mm or higher B... Peel adhesion strength of 1.3 N / mm or more and less than 1.5 N / mm C... Peel adhesion strength is less than 1.3 N / mm

[0066] The components in Tables 1 and 2 are as follows: [(A): Acid-modified styrene elastomer] (A-1): ToughTec M1913 (manufactured by Asahi Kasei Chemicals, maleic anhydride-modified styrene-ethylenebutylene-styrene block copolymer, acid value: 10 mgCH3ONa / g, weight-average molecular weight: 150,000) (A-2): ToughTec M1911 (manufactured by Asahi Kasei Chemicals, maleic anhydride-modified styrene-ethylenebutylene-styrene block copolymer, acid value: 2 mgCH3ONa / g, weight-average molecular weight: 150,000)

[0067] [(B): Isocyanate compounds having two or more isocyanate groups in one molecule] (B-1): Trixene BI7982 (manufactured by Baksenden, a blocked trimer of hexamethylene diisocyanate, solid content concentration: 70% by weight, isocyanate equivalent (molecular weight per isocyanate group): 410 g / eq) (B-2): Takenate B-820NP (manufactured by Mitsui Chemicals, a blocked compound of 1,3-bis(isocyanatemethyl)cyclohexane, solid content concentration: 60% by weight, isocyanate equivalent: 656 g / eq)

[0068] [(C): Fluorine-based polymer microparticles] (C-1): Fluo400XF (manufactured by MicroPowders, PTFE microparticles, average particle size: 3μm) (C-2): Lebron L-5F (manufactured by Daikin Industries, Ltd., PTFE fine particles, average particle size: 5 μm)

[0069] [(D): Olefin polymer microparticles] (D-1): MPP-635XF (MicroPowders, polyethylene microparticles, average particle size: 5 μm, melting point: 124°C) (D-2): Micropro500 (MicroPowders, polypropylene microparticles, average particle size: 6 μm, melting point: 142°C)

[0070] [(E): Solvent] (E-1): Toluene

[0071] [(F): Crosslinking agents other than isocyanate compounds having two or more isocyanate groups in one molecule] (F-1): HP-7200HH (manufactured by DIC Corporation, dicyclopentadiene type epoxy resin, epoxy equivalent: 280g / eq)

[0072] [(G): Curing accelerator] (G-1): 2-Undecylimidazole

[0073] [Table 1]

[0074] Table 2

Claims

1. (A) Acid-modified styrene elastomer, (B) Isocyanate compound having two or more isocyanate groups in one molecule, (C) Fluorine-based polymer fine particles, and (D) Olefin-based polymer fine particles are included. (A) The molar ratio of isocyanate groups in an isocyanate compound having two or more isocyanate groups per molecule to the total acidic groups in an acid-modified styrene elastomer (isocyanate groups / total acidic groups) is 0.3 to 3.

0. (C) The content of fluorine polymer fine particles is 15 to 100 parts by weight per 100 parts by weight of (A) acid-modified styrene elastomer. (D) The content of olefin polymer fine particles is 7 to 55 parts by weight per 100 parts by weight of (A) acid-modified styrene elastomer. Adhesive composition.

2. The adhesive composition according to claim 1, wherein the above (A) acid-modified styrene elastomer is obtained by modifying at least one styrene elastomer selected from the group consisting of styrene-ethylenebutylene-styrene block copolymer and styrene-ethylenepropylene block copolymer with at least one selected from the group consisting of unsaturated carboxylic acids and unsaturated carboxylic acid anhydrides.

3. The adhesive composition according to claim 1, wherein the isocyanate compound having two or more isocyanate groups in one molecule is at least one compound selected from the group consisting of aliphatic polyisocyanates, alicyclic polyisocyanates, and derivatives thereof.

4. The adhesive composition according to claim 1, wherein the above (C) fluorine-based polymer fine particles are fine particles composed of at least one fluorine-based polymer selected from the group consisting of polytetrafluoroethylene, fluorinated ethylene-propylene copolymer, perfluoroalkoxy polymer, tetrafluoroethylene-chlorotrifluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, and polychlorotrifluoroethylene.

5. The adhesive composition according to claim 1, wherein the (D) olefin polymer fine particles are fine particles composed of at least one olefin polymer selected from the group consisting of polyethylene, polypropylene, and ethylene-propylene copolymer.

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

7. An adhesive film comprising the adhesive composition according to any one of claims 1 to 5.

8. An adhesive film made using the adhesive composition described in claim 6.

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