TWI784365B - Adhesive composition - Google Patents

Abstract

The present invention provides an adhesive composition which has excellent electrical properties and can form an adhesive layer with excellent adhesiveness (adhesiveness) after heating and hardening, and can improve the adhesiveness (adhesion) in the lamination step. property) to prevent temporary fixation, peeling and floating of the layer during operation during roll-to-roll. It is an adhesive composition containing carboxyl-containing styrene elastomer, carboxyl-free styrene elastomer, and epoxy resin.

Description

Adhesive composition

The present invention relates to adhesive compositions. Specifically, it relates to an adhesive composition that can be used for bonding electronic parts and the like.

With the miniaturization and weight reduction of electronic equipment, the application of bonding electronic parts and the like is diversifying, and the demand for laminates with adhesive layers is increasing. In addition, flexible printed circuit boards (hereinafter also referred to as FPCs), which are one of electronic parts, need to process a large amount of data at high speed, and the response to high frequency is progressing. In order to increase the frequency of FPC, the low dielectric of the components is required, and the development of low dielectric base film and low dielectric adhesive is in progress.

However, low-dielectric adhesives have low molecular polarity, so it is difficult to exhibit adhesion (adhesion) to substrate films, metal layers, and other components related to electronic parts, and low dielectric Similarly, the base film may have poor adhesion (adhesiveness) to the adhesive. Therefore, in order to have good electrical properties (low relative permittivity, and low dielectric tangent) and to meet the needs of high adhesiveness, it was proposed to use carboxyl-containing styrene-based elastomer (A), and ring An adhesive composition of epoxy resin (B), and a laminate composed of an adhesive layer composed of the adhesive composition and a base film has been proposed (for example, refer to Patent Document 1). [Prior Art Literature] [Patent Document]

[Patent Document 1] International Publication No. 2016/017473

[Problem to be Solved by the Invention]

However, although the adhesive composition of the above-mentioned Patent Document 1 exhibits high adhesiveness (adhesiveness) after heating and hardening, it is known that it is used for lamination with a short heating time in, for example, a manufacturing step of a laminate. During steps, etc., it may not be able to adhere sufficiently to the substrate film and other components related to electronic parts. In the lamination step, if the adhesive composition cannot sufficiently adhere to the base film and other components related to electronic parts, in the manufacture of the laminate, thermal compression is used for temporary fixation during lamination, and roller pairs During the operation of the roll, peeling and floating of the layer may occur. Therefore, various flaws in the laminated body may occur such as lamination defects, gaps caused by fine unevenness generated between layers, and swelling of the layers in the subsequent heating step.

Therefore, the object of the present invention is to provide an adhesive composition that has excellent electrical properties, and can form an adhesive layer with excellent adhesion (adhesiveness) after heating and hardening, and can improve the adhesion in the lamination step. Adhesiveness (adhesiveness) can prevent peeling and floating of layers during temporary fixation and roll-to-roll operation. [Means to solve the problem]

The inventors of the present case have repeatedly and diligently studied in order to solve the above problems, and as a result, they have found an adhesive composition containing at least three components: a carboxyl-containing styrene-based elastomer, a carboxyl-free styrene-based elastomer, and an epoxy resin. , not only expresses high adhesion (adhesion) to the substrate film after heating and hardening, but also exhibits sufficient adhesion (adhesion) to the substrate film in the lamination step, which can solve the above problems, And complete the present invention.

The present invention also includes the following aspects. [1] An adhesive composition comprising a carboxyl-containing styrene-based elastomer, a carboxyl-free styrene-based elastomer, and an epoxy resin. [2] The adhesive composition according to [1], wherein the content of the epoxy resin is 1 to 20 parts by mass based on 100 parts by mass of the adhesive composition. [3] The adhesive composition according to [1] or [2], wherein the content of the carboxyl group-containing styrene-based elastomer is less than 50 parts by mass based on 100 parts by mass of the adhesive composition. [4] The adhesive composition according to any one of [1] to [3], wherein the epoxy resin has a softening point or a melting point of 90°C or lower. [5] The adhesive composition according to any one of [1] to [4], which further contains an organic peroxide. [6] An adhesive layer comprising the adhesive composition according to any one of [1] to [5], the adhesive layer has a storage elastic modulus of 5 at 120°C before hardening ×10 ⁵ Pa or less. [7] An adhesive layer consisting of the adhesive composition according to any one of [1] to [5], the adhesive layer has a storage elastic modulus of 8 at 25°C after hardening ×10 ⁷ Pa or more. [8] An adhesive layer, measured at a frequency of 28 GHz on an adhesive layer formed by hardening the adhesive composition as described in any one of [1] to [5] The relative permittivity is 3.5 or less, and the dielectric tangent is 0.01 or less. [9] A laminate comprising: a base film, and an adhesive layer composed of the adhesive composition according to any one of [1] to [5], or any one of [6] to [8] Any one of the adhesive layers. [10] The laminate according to [9], wherein the base film contains a polyetheretherketone (PEEK) resin. [11] A cover layer film with an adhesive layer, comprising the laminate according to [9] or [10]. [12] A copper-clad laminate comprising the laminate according to [9] or [10]. [13] A printed circuit board comprising the laminate of [9] or [10]. [14] A shielding film comprising the laminate according to [9] or [10]. [15] A printed circuit board with a shielding film, comprising the laminate of [9] or [10]. [Effect of Invention]

According to the present invention, it is possible to provide an adhesive composition which has excellent electrical characteristics and which can form an adhesive layer having excellent adhesiveness (adhesiveness) after heating and hardening, and which can also improve the adhesiveness in the lamination step. (Adhesiveness) can prevent temporary fixation, peeling and floating of layers during operation during roll-to-roll.

Hereinafter, the adhesive composition of the present invention, a laminate including an adhesive layer composed of the adhesive composition, and components related to electronic components including the laminate will be described in detail, but the following The description of the constituent elements is an example of one embodiment of the present invention, and is not limited to these contents.

(adhesive composition) The adhesive composition of the present invention contains carboxyl-containing styrene elastomer, carboxyl-free styrene elastomer, and epoxy resin. The adhesive composition of the present invention may contain other components as necessary.

＜Styrene-based elastomers containing carboxyl groups＞ The carboxyl group-containing styrene-based elastomer is also effective as a component that imparts electrical characteristics in addition to adhesiveness and flexibility of the cured product. If the adhesive composition contains a carboxyl group-containing styrene-based elastomer, even a base film with good electrical characteristics and low polarity, the soft adhesive composition can still fully adhere to the substrate film. The surface, therefore, can exhibit adhesion to the low-polarity skeleton, even if it is a metal layer, because the highly polar carboxyl group can exhibit adhesion, so the adhesion of the adhesive layer will be improved. Also, since the carboxyl group-containing styrene-based elastomer is reactive, the heat resistance and chemical resistance of the adhesive layer are also improved by epoxy curing. The so-called carboxyl-containing styrene-based elastomers refer to copolymers with block and random structures of conjugated diene compounds and aromatic vinyl compounds as the main body, and their hydrogenated products, which are modified with unsaturated carboxylic acids. made by sex. In terms of aromatic vinyl compounds, examples include styrene, tert-butylstyrene, α-methylstyrene, divinylbenzene, 1,1-diphenylethylene, N,N-diethyl- p-Aminoethylstyrene, vinyltoluene, etc. Moreover, examples of the conjugated diene compound include butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, and the like.

The modification of the carboxyl group-containing styrene-based elastomer can be carried out, for example, by copolymerizing an unsaturated carboxylic acid with the styrene-based elastomer during polymerization. Moreover, it can implement by heating and kneading a styrene-type elastomer and an unsaturated carboxylic acid in presence of an organic peroxide. Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, itaconic acid, fumaric acid, maleic anhydride, and itaconic anhydride. The amount of modification by unsaturated carboxylic acid is preferably 0.1 to 10% by mass. The acid value of the carboxyl group-containing styrene-based elastomer is preferably 0.1 to 30 mg KOH/g, more preferably 0.5 to 25 mg KOH/g. When the acid value is 0.1 mg KOH/g or more, the curing system of the adhesive composition is sufficient, and good adhesiveness and heat resistance can be obtained. On the other hand, if the above-mentioned acid value is 25 mg KOH/g or less, since the cohesive force of the adhesive composition is suppressed, the adhesion is excellent and the electrical characteristics are also excellent.

Furthermore, the weight average molecular weight of the carboxyl group-containing styrene-based elastomer is preferably 1 to 500,000, more preferably 30,000 to 300,000, and even more preferably 50,000 to 200,000. When the weight average molecular weight is more than the above-mentioned lower limit, excellent adhesiveness can be exhibited, and the coating property at the time of being melt|dissolved in a solvent and applying also becomes favorable. The compatibility with an epoxy resin will become favorable that a weight average molecular weight is below the said upper limit. The weight average molecular weight is a numerical value obtained by converting the molecular weight measured by gel permeation chromatography (hereinafter also referred to as "GPC") in terms of polystyrene.

Specific examples of carboxyl-containing styrene-based elastomers include styrene-butadiene block copolymers, styrene-ethylene-propylene block copolymers, styrene-butadiene-styrene Segment copolymers, styrene-isoprene-styrene block copolymers, styrene-ethylene-butylene-styrene block copolymers, and styrene-ethylene-propylene-styrene block copolymers, etc. Modification of saturated carboxylic acid. These carboxyl group-containing styrene-based elastomers may be used alone or in combination of two or more. Among the above-mentioned copolymers, styrene-ethylene-butylene-styrene block copolymers and styrene-ethylene-propylene-styrene block copolymers are preferable from the viewpoint of adhesiveness and electrical characteristics. Also, the mass ratio of styrene/ethylene butene in the styrene-ethylene-butylene-styrene block copolymer, and the mass ratio of styrene/ethylene-propylene in the styrene-ethylene-propylene-styrene block copolymer , 10/90-50/50 is more ideal, and 20/80-40/60 is more ideal. If the mass ratio falls within this range, an adhesive composition with excellent adhesive properties can be obtained.

The content of the carboxyl group-containing styrene-based elastomer is preferably less than 50 parts by mass relative to 100 parts by mass of the solid content of the adhesive composition. If the content of the carboxyl group-containing styrene-based elastomer is too large, it will not be possible to improve the adhesion (adhesion) in the lamination step.

＜Carboxyl-free styrene-based elastomer＞ Compared with the aforementioned carboxyl-containing styrene-based elastomers, carboxyl-free styrene-based elastomers have low cohesive force due to the absence of carboxyl-group interactions, and have a low elastic modulus at temperatures higher than the glass transition point. Therefore, by including a carboxyl-free styrene-based elastomer in the adhesive composition, the adhesiveness of the adhesive layer can be improved, especially the adhesiveness (adhesion) in the lamination step can be achieved. improve. The term "carboxyl-free styrene-based elastomer" refers to copolymers mainly composed of block and random structures of conjugated diene compounds and aromatic vinyl compounds, and hydrogenated products thereof. This elastomer is not modified with unsaturated carboxylic acid. The types of aromatic vinyl compounds and conjugated diene compounds constituting styrene-based elastomers, and specific examples of styrene-based elastomers are as described above in <Carboxyl-containing styrene-based elastomers> .

The content of the carboxyl-free styrene-based elastomer is preferably 30 to 70 parts by mass with respect to 100 parts by mass of the solid content of the adhesive composition. Adhesiveness (adhesiveness) in lamination will improve that content of the styrene-type elastomer which does not contain a carboxyl group is more than the said lower limit. On the other hand, if it is below the said upper limit, the component to harden|cure can fully be blended, and heat resistance can be ensured.

＜Epoxy resin＞ Epoxy resin is a component that reacts with the carboxyl group in the above-mentioned carboxyl group-containing styrene-based elastomer, and exhibits high adhesiveness to the adherend and heat resistance of the cured adhesive.

In terms of examples of epoxy resins, such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, or those obtained by hydrogenating them; diglycidyl phthalate, isophthalic acid Diglycidyl Ester, Diglycidyl Terephthalate, Glycidyl Paraben, Diglycidyl Tetrahydrophthalate, Diglycidyl Succinate, Diglycidyl Adipate, Sebis glycidyl acid diglycidyl ester, trimellitic acid triglycidyl ester and other glycidyl ester epoxy resins; ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1 ,6-Hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, neopentylthritol tetraglycidyl ether, tetraphenyl glycidyl ether ethane, triphenyl glycidyl ether ethane, sorbitol Glycidyl ether-based epoxy resins such as polyglycidyl ether and polyglycidyl ether of polyglycerol; glycidylamine-based epoxy resins such as triglycidyl isocyanurate and tetraglycidyl diaminodiphenylmethane; Linear aliphatic epoxy resins such as oxidized polybutadiene and epoxidized soybean oil, etc., but are not limited to these. In addition, novolac epoxy resins containing xylene structures, naphthol novolac epoxy resins, phenol novolak epoxy resins, o-cresol novolak epoxy resins, bisphenol A novolac epoxy resins, etc. can also be used. Novolak type epoxy resin.

Also, as examples of epoxy resins, brominated bisphenol A type epoxy resins, phosphorus-containing epoxy resins, fluorine-containing epoxy resins, dicyclopentadiene-skeleton-containing epoxy resins, naphthalene-skeleton-containing Epoxy resins, anthracene epoxy resins, tertiary catechol epoxy resins, terphenylmethane epoxy resins, tetraphenylethane epoxy resins, biphenyl epoxy resins, biphenyl epoxy resins, Phenol S-type epoxy resin, etc. These epoxy resins may use only 1 type, and may use 2 or more types together. Among the above-mentioned epoxy resins, an epoxy resin not having a hydroxyl group is preferable in view of obtaining an adhesive composition having excellent electrical properties and having good compatibility with styrene-based elastomers. In particular, novolac epoxy resins, such as epoxy resins with the following structure, are epoxy resins with a suitable soft skeleton, so they are not easy to cause brittle fracture of the hardened product. For long-term use of the hardened product of the adhesive composition The stability of the performance will be improved, and because the number of functional groups is high, the heat resistance will also be improved, so it is more ideal.

R為包含亞甲基-芳基-亞甲基的結構、或包含碳數為6以上之脂肪族烴結構的結構，就芳基而言，可列舉如苯、二甲苯、萘、聯苯等，就脂肪族烴而言，可列舉如己烷、二甲基環己烷、二環戊二烯等。 就酚醛清漆型之環氧樹脂的具體例而言，可列舉如三菱化學(股)公司製脂「YX7700」(含二甲苯結構之酚醛清漆型環氧樹脂)、日本化藥(股)公司製之「NC7000L」(萘酚酚醛清漆型環氧樹脂)、新日鐵住金化學(股)公司製之「ESN485」(萘酚酚醛清漆型環氧樹脂)、DIC(股)公司製之「N-690」(甲酚酚醛清漆型環氧樹脂)、DIC(股)公司製之「N-695」(甲酚酚醛清漆型環氧樹脂)等。[chemical 1]

R is a structure containing methylene-aryl-methylene, or a structure containing an aliphatic hydrocarbon structure with a carbon number of 6 or more. Examples of the aryl group include benzene, xylene, naphthalene, biphenyl, etc. , As for aliphatic hydrocarbons, for example, hexane, dimethylcyclohexane, dicyclopentadiene and the like can be cited. Specific examples of novolac-type epoxy resins include Mitsubishi Chemical Co., Ltd. resin "YX7700" (a novolak-type epoxy resin containing a xylene structure), Nippon Kayaku Co., Ltd. "NC7000L" (naphthol novolac epoxy resin), "ESN485" (naphthol novolac epoxy resin) manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., "N- 690" (cresol novolak-type epoxy resin), "N-695" (cresol novolac-type epoxy resin) manufactured by DIC Co., Ltd., and the like.

In addition, the epoxy resin having amine groups can shorten the curing time or lower the curing temperature due to the catalytic action of the amine groups, so that the workability can be improved. Moreover, since it contains an amine group, the adhesiveness with a metal layer improves. In particular, it is more desirable if the epoxy resin is a glycidylamine type epoxy resin. Because the glycidyl amine type epoxy resin is multifunctional, it can be cured in a small amount, and because the molecular skeleton contains amine, it has good compatibility with amine-containing styrene-based elastomers, and it also has the effect of accelerating the reaction. Effect. Moreover, since it contains an amine group, the adhesiveness with a metal layer improves. Specific examples of glycidylamine-type epoxy resins include, for example, tetraglycidyldiaminodiphenylmethane, "jER604" manufactured by Mitsubishi Chemical Co., Ltd., Sumitomo Chemical Co., Ltd. "SUMI-EPOXY ELM434" manufactured by a company, "Araldite MY720", "Araldite MY721", "Araldite MY9512", "Araldite MY9612", "Araldite MY9634", "Araldite MY9663" manufactured by Huntsman Advanced Materials Co., Ltd. "TETRAD-X" and "TETRAD-C" manufactured by Gas Chemical Co., Ltd.

The epoxy resin used in the present invention preferably has two or more epoxy groups in one molecule. Because it can form a cross-linked structure by reacting with carboxyl-containing styrene-based elastomers, it exhibits high heat resistance. Also, when an epoxy resin having two or more epoxy groups is used, the degree of crosslinking with the carboxyl group-containing styrene-based elastomer is sufficient, and sufficient heat resistance can be obtained.

The content of the epoxy resin is preferably 1 to 20 parts by mass with respect to 100 parts by mass of the solid content of the adhesive composition. If the content of the above-mentioned epoxy resin is more than the above-mentioned lower limit, the adhesive composition can be fully cured, and good heat resistance and chemical resistance can be ensured. On the other hand, since adhesiveness will fall when there is too much content of an epoxy resin, favorable adhesiveness can be securable if it is below the said upper limit. If the content of the epoxy resin is too large, the improvement of the adhesion (adhesion) in the lamination step cannot be achieved.

The softening point or melting point of the above-mentioned epoxy resin is preferably below 90°C. If the softening point or melting point of the epoxy resin is below 90°C, the elastic modulus of the adhesive composition before hardening can be reduced in the high temperature range, and the adhesive composition after hardening can be reduced in the normal temperature range (room temperature) ) modulus of elasticity increases.

＜Other ingredients＞ In the adhesive composition, in addition to the above-mentioned carboxyl-containing styrene-based elastomer, carboxyl-free styrene-based elastomer, and epoxy resin, it can be contained in an amount that does not affect the function of the adhesive composition. Carboxyl-containing styrene-based elastomers and other thermoplastic resins other than carboxyl-free styrene-based elastomers, tackifiers, flame retardants, hardeners, hardening accelerators, coupling agents, heat-resistant aging agents, leveling Agents, defoamers, inorganic fillers, pigments, and solvents.

A more desirable embodiment of the adhesive composition containing other components includes, for example, an adhesive composition containing an organic peroxide. Thereby, the styrene-based elastomer without carboxyl group can also be cross-linked, which can further improve the heat resistance and chemical resistance of the adhesive layer. As far as organic peroxides are concerned, those generally known as radical polymerization initiators can be used, such as benzoyl peroxide, lauryl peroxide, tert-butyl peroxypivalate, ethyl peroxide, etc. tert-butyl hexanoate, 1,1'-bis-(tert-butylperoxy)cyclohexane, tertiary pentyl peroxy-2-ethylhexanoate, 2-ethylhexyl peroxide Organic peroxides such as tertiary hexyl ester.

Among the above-mentioned other components, the above-mentioned other thermoplastic resins include, for example, phenoxy resins, polyamide resins, polyester resins, polycarbonate resins, polyphenylene oxide resins, polyurethane resins, Polyacetal resins, polyethylene-based resins, polypropylene-based resins, polyvinyl-based resins, and the like. These thermoplastic resins may be used alone or in combination of two or more.

In terms of the above-mentioned tackifiers, for example, coumarone-indene resins, terpene resins, terpene-phenolic resins, rosin resins, p-tert-butylphenol-acetylene resins, phenol-formaldehyde resins, 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.

The above-mentioned flame retardant may be any of organic flame retardants and inorganic flame retardants. Examples of organic flame retardants include melamine phosphate, melamine polyphosphate, guanidine phosphate, guanidine polyphosphate, ammonium phosphate, ammonium polyphosphate, ammonium phosphatamide, ammonium polyphosphate amide, urethane formate, Polyphosphate urethane formate, ginseng (diethylphosphinate) aluminum, ginseng (methylethylphosphinate) aluminum, ginseng (diphenylphosphinate) aluminum, bis(diethylphosphinate) Zinc, bis(methylethylphosphinate)zinc, bis(diphenylphosphinate)zinc, bis(diethylphosphinate)oxytitanium, tetrakis(diethylphosphinate)titanium, bis( Phosphorous flame retardants such as methyl ethyl phosphinate) oxytitanium, tetrakis (methylethyl phosphinate) titanium, bis(diphenylphosphinate) oxytitanium, tetrakis (diphenylphosphinate) titanium, etc. Nitrogen series compounds such as melamine, melam, melamine cyanurate, etc., cyanuric acid compounds, isocyanuric acid compounds, triazole compounds, tetrazole compounds, diazo compounds, urea, etc. Flame retardants; silicon-based flame retardants such as polysiloxane compounds and silane compounds. In addition, in terms of inorganic flame retardants, metal hydroxides such as aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, barium hydroxide, calcium hydroxide; tin oxide, aluminum oxide, magnesium oxide, zirconium oxide, etc. , zinc oxide, molybdenum oxide, nickel oxide and other metal oxides; zinc carbonate, magnesium carbonate, barium carbonate, zinc borate, hydrated glass, etc. Two or more of these flame retardants may be used in combination.

Examples of the curing agent include amine-based curing agents and acid anhydride-based curing agents, but are not limited thereto. Examples of the amine-based curing agent include melamine resins such as methylated melamine resins, butylated melamine resins, and benzoguanamine resins, dicyandiamine, and 4,4'-diphenyldiaminosulfone. Moreover, as an acid anhydride, an aromatic acid anhydride and an aliphatic acid anhydride are mentioned, for example. These curing agents may be used alone or in combination of two or more. The content of the curing agent is preferably 0.5 to 100 parts by mass, more preferably 5 to 70 parts by mass, relative to 100 parts by mass of the adhesive composition.

The above-mentioned hardening accelerators are used to accelerate the reaction between carboxyl-containing styrene-based elastomers and epoxy resins. Tertiary amine-based hardening accelerators, third-level ammonium salt-based hardening accelerators, and imidazole-based hardening accelerators can be used. agent etc.

As for the tertiary amine hardening accelerator, examples include benzyldimethylamine, 2-(dimethylaminomethyl)phenol, 2,4,6-paraffin(dimethylaminomethyl)phenol , tetramethylguanidine, triethanolamine, N,N'-dimethylpiperone, triethylenediamine, 1,8-diazabicyclo[5.4.0]undecene, etc.

As for the tertiary ammonium salt-based hardening accelerator, formate, octanoate, p-toluenesulfonate, phthalate, 1,8-diazabicyclo[5.4.0]undecene Formate, phenate or phenol novolac resin salt, 1,5-diazabicyclo[4.3.0]nonene formate, octanoate, p-toluenesulfonate, phthalate, phenol Salt or phenol novolak resin salt etc.

Examples of imidazole-based hardening accelerators 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-trimethazolium, 2,4-diamino-6-[2'-undecylimidazolyl-(1') ]Ethyl-s-trimethazolium, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]ethyl-s-trimethazolium, 2,4 -Diamino-6-[2'-methylimidazolyl-(1')]ethyl-s-tri-isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct , 2-phenyl-4,5-dimethylolimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, etc. These curing accelerators may be used alone or in combination of two or more.

When the adhesive composition contains a hardening accelerator, the content of the hardening accelerator is preferably 0.05 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the adhesive composition. If the content of the hardening accelerator falls within the above range, the reaction between the carboxyl group-containing styrene-based elastomer and the epoxy resin, and the reaction between the epoxy resins can be easily carried out, and the adhesion and heat resistance can be easily ensured. .

Also, in terms of the above-mentioned coupling agent, vinyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropyl Methyldimethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-ureidopropyl Triethoxysilane, 3-mercaptopropylmethyldimethoxysilane, bis(triethoxysilylpropyl)tetrasulfide, 3-isocyanatopropyltriethoxysilane, imidazole silane, etc. Silane-based coupling agent; titanate-based coupling agent; aluminate-based coupling agent; zirconium-based coupling agent, etc. These may be used alone or in combination of two or more.

In terms of the above-mentioned anti-aging agents, such as 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, neopentylthritol tetra[ 3-(3,5-di-tert-butyl-4-hydroxyphenol)], triethylene glycol-bis[3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propane phenolic acid ester] and other phenol antioxidants; sulfur-based antioxidants such as 3,3'-dilauryl sulfur dipropionate and 3,3'-dimyristyl sulfur dipropionate; ginseng nonylphenyl phosphite Phosphorous antioxidants such as ginseng (2,4-di-tert-butylphenyl) phosphite, etc. These may be used alone or in combination of two or more.

Examples of the inorganic fillers include powders made of titanium oxide, aluminum oxide, zinc oxide, carbon black, silicon dioxide, talc, copper, and silver. These may be used alone or in combination of two or more.

(adhesive layer) The adhesive layer of the present invention is composed of the above-mentioned adhesive composition of the present invention. The adhesive composition forming the adhesive layer can be hardened. The curing method is not particularly limited, and can be appropriately selected according to the purpose, and examples thereof include thermal curing and the like. The thickness of the adhesive layer is not particularly limited and can be appropriately selected according to the purpose. For example, it is preferably 3-100 μm, more preferably 5-70 μm, and even more preferably 10-50 μm.

＜Manufacturing method of adhesive layer＞ The adhesive layer can be produced by forming a film of the above-mentioned adhesive composition. The above-mentioned adhesive composition can be produced by mixing a carboxyl group-containing styrene-based elastomer, a carboxyl-free styrene-based elastomer, an epoxy resin, and other components. The mixing method is not particularly limited, as long as the adhesive composition is uniform. The adhesive composition usually uses a solvent from the viewpoint of being ideally usable in the state of a solution or a dispersion. For the solvent, methanol, ethanol, isopropanol, n-propanol, isobutanol, n-butanol, benzyl alcohol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, etc. , diacetone alcohol and other alcohols; acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone, cyclohexanone, isophorone and other ketones; toluene, xylene, ethylbenzene, homo Aromatic hydrocarbons such as trimethylbenzene; esters such as methyl acetate, ethyl acetate, ethylene glycol monomethyl ether acetate, 3-methoxybutyl acetate; hexane, heptane, cyclohexane, Aliphatic hydrocarbons such as methylcyclohexane, etc. These solvents may be used alone or in combination of two or more. If the adhesive composition is a solution or dispersion (resin varnish) containing a solvent, the coating of the substrate film and the formation of the adhesive layer can be carried out smoothly, and the adhesion of the desired thickness can be easily obtained agent layer. When the adhesive composition contains a solvent, the solid content concentration is preferably in the range of 3 to 80% by mass, more preferably in the range of 10 to 50% by mass, in consideration of workability including formation of the adhesive layer. If the solid content concentration is 80 mass % or less, the viscosity of a solution will be appropriate, and it will become easy to coat uniformly. In a more specific embodiment of the method for producing the adhesive layer, after the resin varnish layer is formed by applying the resin varnish containing the above-mentioned adhesive composition and solvent to the surface of the substrate film, the resin varnish layer can be formed from the resin The varnish layer removes the solvent, thereby forming a B-staged adhesive layer. Here, the B-stage state of the adhesive layer refers to an uncured state of the adhesive composition or a semi-hardened state where a part of the adhesive composition begins to harden. step-by-step status. Here, the method of coating the resin varnish on the substrate film is not particularly limited, and can be appropriately selected according to the purpose, such as spray method, spin coating method, dip coating method, roll coating method, Blade coating method, doctor roll method, doctor blade method, curtain coating method, slit coating method, screen printing method, inkjet method, dispensing method, etc. The adhesive layer in the above B-stage state can be further heated to form a hardened adhesive layer.

<Characteristics of Adhesive Layer> The adhesive layer of the present invention preferably has a storage elastic modulus at 120° C. before hardening of 1×10 ³ Pa or more and 5×10 ⁵ Pa or less. If the storage elastic modulus is 5×10 ⁵ Pa or less, the adhesive layer will be easily bonded to other components related to the base film and electronic parts because the storage elastic modulus is low at the temperature of the lamination step. Do sticking.

[Storage modulus of elasticity (Pa)] For the storage elastic modulus of the adhesive layer, for example, an adhesive film with a thickness of 100 μm can be prepared for a sample composed of the adhesive layer, and the viscoelasticity measurement device (RSA-G2 manufactured by TA Instruments) can be used for measurement. Under the conditions of frequency 1Hz and heating rate 5°C/min, it was measured in accordance with JIS K7244 and obtained.

The adhesive layer of the present invention preferably has a storage elastic modulus of not less than 8×10 ⁷ Pa and not more than 5×10 ⁹ Pa at 25° C. after hardening. If the storage elastic modulus is 8×10 ⁷ Pa or more, the adhesive layer can maintain the adhesive force with the base film and other components related to electronic parts because the storage elastic modulus at room temperature is high.

The adhesive layer of the present invention obtained by hardening the adhesive composition has a relative permittivity (εr) of 3.5 or less and a dielectric tangent (tanδ) of 0.01 measured at a frequency of 28 GHz. The following are ideal. If the relative permittivity is 3.5 or less and the dielectric tangent is 0.01 or less, it can be ideally used even in FPC-related products that require strict electrical characteristics.

[Relative permittivity and dielectric tangent] For the relative permittivity and dielectric tangent of the adhesive layer, Network Analyzers MS46122B (manufactured by Anritsu Corporation) and open resonator Fabry-Perro DPS-03 (manufactured by KEYCOM Corporation) can be used, and the open resonator According to the method, the temperature is 23°C and the frequency is 28GHz.

(Laminate) The laminate of the present invention includes a base film, and the above-mentioned adhesive layer on at least one surface of the base film.

＜Base Film＞ The base film used in the present invention can be selected according to the application of the laminate. For example, when the laminate is used as a cover layer film or a copper clad laminate (CCL), polyimide film, polyether ether ketone film, polyphenylene sulfide film, aramid film, etc. , polyethylene naphthalate film, and liquid crystal polymer film, etc. Among them, polyimide film, polyether ether ketone (PEEK) film, polyethylene naphthalate film, and liquid crystal polymer film are preferable from the viewpoint of adhesiveness and electrical characteristics.

Also, when using the laminate of the present invention as an adhesive sheet (bonding sheet), the base film must be a release film, such as polyethylene terephthalate film, polyethylene film, polypropylene film, Silicone release paper, polyolefin resin coated paper, TPX (polymethylpentene) film, and fluorine resin film, etc.

When the laminate of the present invention is used as a shielding film, the base film must be a film having electromagnetic wave shielding capability, for example, a laminate of a protective insulating layer and a metal foil.

(Surface film) A more desirable embodiment of the laminate of the present invention includes, for example, a cover layer film. When manufacturing FPC, in order to protect the wiring part, a laminate with an adhesive layer called "cover film" is usually used. This cover film has an insulating resin layer and an adhesive layer formed on the surface. For example, the cover layer film is a laminate in which the above-mentioned adhesive layer is formed on at least one surface of the above-mentioned base film, and the peeling of the base film and the adhesive layer is generally difficult. The thickness of the base film contained in the cover layer film is preferably 5 to 100 μm, more preferably 5 to 50 μm, even more preferably 5 to 30 μm. If the thickness of the base film is not more than the above-mentioned upper limit, the cover layer film can be thinned. If the thickness of the base film is more than the above-mentioned lower limit, the design of the printed circuit board can be easily carried out, and the handling is also preferable. In the method of producing a cover layer film, for example, after coating a resin varnish containing the above-mentioned adhesive composition and a solvent on the surface of the above-mentioned base film to form a resin varnish layer, the solvent may be removed from the resin varnish layer , thereby manufacturing a cover layer film having an adhesive layer in a B-stage state. The drying temperature when removing the solvent is preferably 40 to 250°C, more preferably 70 to 170°C. Drying is performed by passing the laminate coated with the adhesive composition through a furnace that performs hot air drying, far-infrared heating, and high-frequency induction heating. Moreover, a release film may be laminated|stacked on the surface of an adhesive bond layer for uses, such as storage, as needed. As the release film, polyethylene terephthalate film, polyethylene film, polypropylene film, silicone release-treated paper, polyolefin resin coated paper, TPX film, fluororesin film can be used Wait for the public. The cover layer film of the present invention uses the low-dielectric adhesive composition of the present invention, so it can achieve high-speed transmission of electronic devices and has excellent bonding stability with electronic devices.

(adhesive sheet) As a more desirable embodiment of the laminate of the present invention, an adhesive sheet is exemplified. Adhesive sheet is one in which the above-mentioned adhesive layer is formed on the surface of a release film (substrate film). In addition, the adhesive sheet may have an adhesive layer between two release films. When using an adhesive sheet, it is used after peeling off the release film. As the release film, the same ones as described in the above (cover layer film) can be used. The thickness of the base film contained in the adhesive sheet is preferably 5 to 100 μm, more preferably 25 to 75 μm, and still more preferably 38 to 50 μm. If the thickness of the base film falls within the above-mentioned range, the production of the adhesive sheet is easy and the handling is also good. As for the method of producing the adhesive sheet, for example, there is a method of applying the resin varnish containing the above-mentioned adhesive composition and solvent to the surface of the release film, and drying it in the same way as the case of the above-mentioned surface layer film. . The adhesive sheet of the present invention uses the low-dielectric adhesive composition of the present invention, so it can achieve high-speed transmission of electronic devices and has excellent bonding stability with electronic devices.

(Copper Clad Laminates (CCL)) A more desirable embodiment of the laminate of the present invention includes a copper-clad laminate in which copper foil is bonded to the adhesive layer in the laminate of the present invention. A copper-clad laminate uses the above-mentioned laminate and bonds copper foil, for example, to a substrate film, an adhesive layer, and copper foil in this order. In addition, the adhesive layer and the copper foil may also be formed on both surfaces of the base film. The adhesive composition used in the present invention is also excellent in adhesion to objects containing copper. The copper-clad laminate of the present invention uses the low-dielectric adhesive composition of the present invention, so it can achieve high-speed transmission of electronic equipment and has excellent bonding stability.

As for the method of manufacturing copper-clad laminates, for example, the adhesive layer of the above-mentioned laminate is brought into surface contact with the copper foil, and thermal lamination is performed at 80°C to 150°C, followed by post-hardening. A method of hardening an adhesive layer. The post-curing conditions can be set, for example, at 100° C. to 200° C. and 30 minutes to 4 hours in an inert gas environment. In addition, the said copper foil is not specifically limited, Electrolytic copper foil, rolled copper foil, etc. can be used.

(A printed circuit board) A preferred embodiment of the laminate of the present invention is, for example, a printed circuit board in which copper wiring is bonded to the adhesive layer in the laminate of the present invention. A printed circuit board can be obtained by forming an electronic circuit on the above-mentioned copper-clad laminated board. The printed circuit board is formed by bonding the base film and the copper wiring using the above-mentioned laminate, and is constructed in this order of the base film, the adhesive layer, and the copper wiring. In addition, the adhesive layer and copper wiring may be formed on both surfaces of the base film. For example, a printed circuit board is manufactured by bonding the cover layer film to the surface having the wiring portion through the adhesive layer by heat pressing or the like. The printed circuit board of the present invention uses the low-dielectric adhesive composition of the present invention, so it can achieve high-speed transmission of electronic equipment and has excellent bonding stability. In terms of the method of manufacturing the printed circuit board of the present invention, for example, the adhesive layer of the above-mentioned laminate is brought into contact with the copper wiring, and thermal lamination is performed at 80°C to 150°C, followed by post-curing, whereby A method of hardening an adhesive layer. The post-curing conditions can be set, for example, at 100° C. to 200° C. and 30 minutes to 4 hours. The shape of the said copper wiring is not specifically limited, What is necessary is just to select a shape etc. suitably as desired.

(shielding film) As a preferred embodiment of the laminate of the present invention, a masking film is exemplified. Shielding film is a film used for shielding in various electronic devices in order to block electromagnetic wave noise that affects various electronic devices such as computers, mobile phones, and analysis equipment and becomes the cause of malfunction. Also known as electromagnetic wave shielding film. The electromagnetic shielding film is formed by laminating, for example, an insulating resin layer, a metal layer, and the adhesive layer of the present invention in this order. The shielding film of the present invention uses the low-dielectric adhesive composition of the present invention, so it can achieve high-speed transmission of electronic devices and has excellent bonding stability with electronic devices.

(printed circuit board with shielding film) A preferred embodiment of the laminate of the present invention includes, for example, a printed circuit board with a masking film. A printed circuit board with a shielding film is a printed circuit board with a printed circuit on at least one side of the substrate, and the above-mentioned electromagnetic wave shielding film is pasted on it. The printed circuit board with shielding film includes, for example, a printed circuit board, an insulating film adjacent to the surface of the printed circuit board on which the printed circuit is provided, and the above-mentioned electromagnetic wave shielding film. The printed circuit board with shielding film of the present invention uses the low-dielectric adhesive composition of the present invention, so it can achieve high-speed transmission of electronic equipment and has excellent adhesion stability. [Example]

Although the following examples are given and the present invention will be described in more detail, the scope of the present invention is not limited to these examples. In addition, in the following, "parts" and "%" are based on mass unless otherwise specified.

(Carboxyl-containing styrene-based elastomer) "Tuftec M1911 (trade name)" (maleic acid-modified styrene-ethylene-butylene-styrene block copolymer) manufactured by Asahi Kasei Co., Ltd. was used. The acid value of this copolymer was 2 mg KOH/g, the ratio of styrene/ethylene butene was 30/70, and the weight average molecular weight was 69,000. (Styrene-based elastomers without carboxyl groups) "Tuftec P1500 (trade name)" (hydrogenated styrene elastomer) manufactured by Asahi Kasei Co., Ltd. was used. The acid value of this copolymer was 0 mg KOH/g, the ratio of styrene/ethylene butene was 30/70, and the weight average molecular weight was 67,000. (epoxy resin) "YX7700 (trade name)" (epoxy resin, softening point: 65° C.) manufactured by Mitsubishi Chemical Co., Ltd. was used. (Perbutyl E) As the organic peroxide, "Perbutyl E (trade name)" which is a peroxyester manufactured by NOF Co., Ltd. was used. (solvent) A mixed solvent (mass ratio=90:10) composed of toluene and methyl ethyl ketone was used. (substrate film) "Shin-Etsu Sepla Film PEEK" (polyether ether ketone, thickness 50 μm) manufactured by Shin-Etsu Polymer Co., Ltd. was used as the base film. (electrolytic copper foil) "TQ-M7-VSP" (electrodeposited copper foil, thickness 12 μm, glossy surface Rz 1.27 μm, glossy surface Ra 0.197 μm, glossy surface Rsm 12.95 μm) manufactured by Mitsui Metal Mining Co., Ltd. was used as the electrodeposited copper foil. The surface roughness of the glossy surface is the value obtained by measuring the roughness curve using a laser microscope and following JIS B 0601:2013 (ISO 4287:1997 Amd.1:2009) from the roughness curve. (release film) As the release film, NP75SA (polysiloxane release PET film, 50 μm) manufactured by PANAC was used.

(Example 1) Each component constituting the adhesive layer shown in Table 1 was contained in the ratio shown in Table 1, and these components were dissolved in a solvent to prepare a resin varnish having a solid content concentration of 20% by mass. Corona treatment is performed on the surface of the substrate film. The resin varnish was coated on the surface of the substrate film, dried in an oven at 110°C for 4 minutes, and the toluene was volatilized to form an adhesive layer, and the substrate film with the adhesive was obtained. The adhesive layer of the adhesive laminate was superimposed in a state of being in contact with the glossy surface of the electrolytic copper foil, and thermally laminated at 120°C to obtain an adhesive laminate before hardening. The pre-cured adhesive laminate was post-cured at 150° C. for 60 minutes to harden the adhesive layer to obtain a cured adhesive laminate. The adhesion force (N/cm) between the electrodeposited copper foil and the base film of the adhesive laminated body before hardening and the adhesive laminated body after hardening of Example 1 was measured.

[Adhesion force (N/cm)] By cutting the adhesive laminate before hardening and the adhesive laminate after hardening into a test body with a width of 25mm, and following JIS Z0237: 2009 (adhesive tape, adhesive sheet test method), measure the peeling The adhesion force was measured by the peel strength when the electrodeposited copper foil was peeled off from the adhesive-attached base film fixed on the support under the conditions of speed 0.3m/min and peel angle 180°.

Then, the storage modulus (Pa) of the adhesive layer of Example 1 at 120° C. before hardening and the storage elastic modulus (Pa) at 25° C. after hardening were also measured.

[Storage modulus of elasticity (Pa)] For the storage elastic modulus of the adhesive layer, an adhesive film with a thickness of 100 μm was made for the sample composed of the adhesive layer, and the measurement frequency was 1 Hz using a viscoelasticity measuring device (RSA-G2 manufactured by TA Instruments Co., Ltd.) , Measured in accordance with JIS K7244 at a heating rate of 5°C/min. The test sample is to roll-coat the resin varnish on the release film, then place the coated film in an oven and dry it at 110°C for 4 minutes to form a B-stage adhesive layer ( Thickness 50μm). Then, the adhesive layer was thermally laminated at 120° C. in a state where the adhesive surfaces were in contact with each other to form an adhesive film (thickness: 100 μm) before hardening. Put the unhardened adhesive film (thickness 100 μm) in an oven, heat and harden at 150°C for 60 minutes, and make a hardened adhesive film (100mm×100mm). The release film was peeled off from the adhesive film and the storage elastic modulus (Pa) of the adhesive layer was measured.

The relative permittivity and dielectric tangent of the adhesive layer in the laminate of Example 1 were also measured at a frequency of 28 GHz.

[Relative permittivity and dielectric tangent] For the relative permittivity and dielectric tangent of the adhesive layer, Network Analyzers MS46122B (manufactured by Anritsu Corporation) and an open resonator Fabry-Pero DPS-03 (manufactured by KEYCOM Corporation) were used, and the open resonator According to the method, the temperature is 23°C and the frequency is 28GHz. The test sample is to roll-coat the resin varnish on the release film, then place the coated film in an oven and dry it at 110°C for 4 minutes to form a B-stage adhesive layer ( Thickness 50μm). Then, the adhesive layer was thermally laminated at 120° C. in a state where the adhesive surfaces were in contact with each other to form an adhesive film (thickness: 100 μm) before hardening. Put the unhardened adhesive film (thickness 100 μm) in an oven, heat and harden at 150°C for 60 minutes, and make a hardened adhesive film (100mm×100mm). The release film was peeled off from the hardened adhesive film and the relative dielectric constant and dielectric tangent of the adhesive layer were measured.

Each measurement result is shown in Table 1.

(Example 2 to Example 5) In Example 1, the types and blending amounts of the components constituting the adhesive layer were changed as shown in Table 1, and the laminates of Examples 2 to 5 were produced in the same manner as in Example 1. . The evaluation similar to Example 1 was performed about the obtained laminated body. The results are shown in Table 1.

(Comparative example 1 to comparative example 4) In Example 1, except that the types and blending amounts of the components constituting the adhesive layer were changed as shown in Table 1, laminates of Comparative Examples 1 to 4 were produced in the same manner as in Example 1. . The evaluation similar to Example 1 was performed about the obtained laminated body. The results are shown in Table 1.

[Table 1] Components of the adhesive layer Adhesive force(N/cm) Storage modulus of elasticity (Pa) electrical characteristics M1911 P1500 YX7700 Perbutyl E 120°C lamination Hardening after 150°C 25°C 120°C Relative permittivity Dielectric tangent Example 1 45.0 45.0 10 0 3.0 8.0 1.3E+08 2.0E+05 2.43 0.0070 Example 2 45.0 45.0 10 3 3.1 9.0 1.3E+08 2.3E+05 2.45 0.0075 Example 3 47.5 47.5 5 0 3.0 8.0 1.3E+08 2.0E+05 2.46 0.0045 Example 4 40.0 55.0 5 0 3.1 8.3 9.0E+07 4.0E+05 2.45 0.0041 Example 5 40.0 55.0 5 3 3.1 8.8 9.1E+07 4.5E+05 2.47 0.0047 Comparative example 1 95.0 0 5 0 2.1 9.5 7.2E+07 1.1E+06 2.45 0.0047 Comparative example 2 0 95.0 5 0 3.7 3.3 9.0E+07 2.6E+05 2.44 0.0045 Comparative example 3 0 100 0 0 3.6 3.6 6.2E+07 3.1E+05 2.45 0.0009 Comparative example 4 50.0 50.0 0 0 3.1 6.9 6.5E+07 5.5E+05 2.46 0.0010 As shown in Examples 1 to 5, the adhesive layer composed of the adhesive composition of the present invention has excellent adhesiveness (adhesiveness) after heating and hardening, and the adhesiveness (adhesiveness) during the lamination step is excellent. properties) are also excellent.

This application claims priority based on Japanese Patent Application No. 2019-230539 filed on December 20, 2019, and uses all the contents of the Japanese patent application. [industrial availability]

A laminate having an adhesive layer composed of the adhesive composition of the present invention can be ideally used in electronic devices such as smart phones, mobile phones, optical modules, digital cameras, game machines, notebook computers, and medical appliances. Manufacturing of FPC-related products for equipment.

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Claims (13)

An adhesive composition, containing carboxyl-containing styrene-based elastomers, carboxyl-free styrene-based elastomers, and epoxy resins, with respect to 100 parts by mass of the adhesive composition, the carboxyl-containing styrene The content of the elastomer is less than 50 parts by mass, and the content of the carboxyl-free styrene-based elastomer is 30 to 70 parts by mass relative to 100 parts by mass of the adhesive composition. 100 parts by mass, the content of the epoxy resin is 1-20 parts by mass. The adhesive composition according to claim 1, wherein the epoxy resin has a softening point or a melting point of 90°C or lower. The adhesive composition according to any one of Claims 1 to 2 further contains an organic peroxide. An adhesive layer consisting of the adhesive composition according to any one of claims 1 to 3, the adhesive layer has a storage elastic modulus of 5×10 ⁵ Pa or less at 120°C before hardening . An adhesive layer consisting of the adhesive composition according to any one of claims 1 to 3, the adhesive layer has a storage elastic modulus of 8×10 ⁷ Pa or more at 25°C after hardening . An adhesive layer, the relative dielectric constant of the adhesive layer measured by the adhesive layer formed by hardening the adhesive composition according to any one of claims 1 to 3 at a frequency of 28 GHz 3.5 or less, and a dielectric tangent of 0.01 or less. A laminate comprising: a base film, and an adhesive layer composed of the adhesive composition according to any one of claims 1 to 3, or the adhesive according to any one of claims 4 to 6 agent layer. The laminate according to claim 7, wherein the base film contains polyetheretherketone (PEEK) resin. A surface coating film with an adhesive layer, comprising the laminate according to claim 7 or 8. A copper-clad laminate, comprising the laminate according to claim 7 or 8. A printed circuit board comprising the laminate according to claim 7 or 8. A shielding film comprising the laminate according to claim 7 or 8. A printed circuit board with a shielding film, comprising the laminate according to claim 7 or 8.