JP2023046722A - Adhesive composition, laminated film, and printed wiring board - Google Patents

Abstract

To provide an adhesive composition that has low dielectric constant and excellent storage stability, a laminated film including a cured layer of the adhesive composition, and a printed wiring board including the laminated film.SOLUTION: An adhesive composition contains a styrenic elastomer not subjected to acid modification, a polyphenylene ether, a curing agent having an unsaturated bond or a peroxide bond, an acid-modified elastomer, an epoxy resin, and a curing agent for epoxy resin. Relative to 100 pts.wt. of the styrenic elastomer, the curing agent having an unsaturated bond or a peroxide bond is 0.1-2 pts.wt.SELECTED DRAWING: None

Description

The present invention relates to adhesive compositions, laminated films, and printed wiring boards.

2. Description of the Related Art In recent years, electronic devices such as portable personal computers and mobile phones are becoming more sophisticated, smaller, and more multifunctional. Along with this, there is a strong demand for higher density, smaller size, and thinner thickness for electronic components that constitute electronic devices.

Furthermore, with the progress of information technology (IT) or information communication technology (ICT), it is required to process large amounts of information at high speed. Along with this, transmission signals are becoming higher in frequency, and materials constituting printed wiring boards are required to have a low dielectric constant (ε) and a low dielectric loss tangent (tan δ).

As a low dielectric adhesive composition, for example, materials described in Patent Documents 1 and 2 are known. Patent Document 1 describes an adhesive composition containing a modified polyolefin resin and an epoxy resin. Patent Document 2 describes an adhesive composition containing a vinyl compound having a polyphenylene ether skeleton, a maleimide resin, and a thermoplastic elastomer.

WO2016/047289 WO2016/117554

An adhesive composition containing an epoxy resin has a high curing speed, but a laminate with an adhesive layer formed by coating the adhesive composition on a base film has excellent storage stability and a long shelf life ( A long shelf life is required. In recent years, from the viewpoint of further high-speed processing of information, the adhesive composition is required to have high adhesive strength to the modified polyimide film after curing.

However, although the adhesive compositions described in Patent Documents 1 and 2 have been improved, they are still insufficient and further improvements are required.

The present invention provides an adhesive composition having a low dielectric constant and excellent storage stability, a laminated film having a cured layer obtained by curing the adhesive composition, and a printed wiring board provided with the laminated film. With the goal.

A first aspect of the present invention comprises a non-acid-modified styrene elastomer, a polyphenylene ether, a curing agent having an unsaturated bond or a peroxide bond, an acid-modified elastomer, an epoxy resin, and a curing agent for an epoxy resin. and a curing agent having an unsaturated bond or a peroxide bond in a ratio of 0.1 to 2 parts by weight with respect to 100 parts by weight of the styrene elastomer. be.

A second aspect is characterized in that, in the adhesive composition of the first aspect, the ratio of the epoxy resin to 50 parts by weight of the acid-modified elastomer is 1 to 10 parts by weight.

A third aspect is characterized in that, in the adhesive composition of the first or second aspect, the ratio of the polyphenylene ether to 100 parts by weight of the styrene-based elastomer is 25 to 75 parts by weight.

A fourth aspect is the adhesive composition of any one of the first to third aspects, wherein the ratio of the acid-modified elastomer to 100 parts by weight of the styrene-based elastomer is 20 to 80 parts by weight. .

A fifth aspect is the adhesive composition of any one of the first to fourth aspects, wherein the ratio of the epoxy resin curing agent to 50 parts by weight of the acid-modified elastomer is 0.01 to 1.5 parts by weight. It is characterized by

A sixth aspect is a laminated film having a cured layer formed by curing the adhesive composition of any one of the first to fifth aspects on a base film.

A seventh aspect is a printed wiring board comprising the laminated film of the sixth aspect.

The adhesive composition of the present invention has a low dielectric constant and excellent storage stability. Therefore, it is suitable as a laminated film having a cured layer in which the adhesive is cured, and as an adhesive for a printed wiring board provided with the laminated film.

The present invention will be described below based on preferred embodiments.

The adhesive composition of the embodiment comprises a non-acid-modified styrene elastomer, polyphenylene ether, a curing agent having an unsaturated bond or a peroxide bond, an acid-modified elastomer, an epoxy resin, and a curing agent for epoxy resin. agent. The adhesive composition of the embodiment may use one type of styrene-based elastomer, or may use two or more types of styrene-based elastomers in combination.

<Styrene-based elastomer>
The adhesive composition of the embodiment contains a styrenic elastomer. This styrene-based elastomer is a styrene-based elastomer that has not been acid-modified. The styrene-based elastomer mainly contributes to low dielectric properties, heat resistance, improved adhesiveness of the adhesive composition, and improved flexibility when the adhesive composition is formed into a film.

Styrenic elastomers include copolymers having polyolefin blocks and polystyrene blocks. At least one selected from ethylene, propylene, butene, isobutene, butadiene, isoprene and the like can be used as the olefin used as the monomer of the polyolefin block. Units derived from dienes such as butadiene and isoprene may be converted into units such as ethylene, propylene and butylene (butene) by hydrogenation (hydrogenation).

Specific examples of styrene-based thermoplastic elastomers include styrene-ethylene-butylene-styrene (SEBS), styrene-ethylene-propylene-styrene (SEPS), styrene-butylene-styrene (SBS), and styrene-isoprene-styrene (SIS). At least one selected from The weight ratio of styrene units in the styrene-based thermoplastic elastomer is preferably 10-40% by weight, more preferably 10-30% by weight, and even more preferably 10-25% by weight, relative to the total weight of the styrene-based thermoplastic elastomer. .

<Polyphenylene ether>
The adhesive composition of embodiments contains a polyphenylene ether. A polyphenylene ether is a compound having -[O-Y]- or -[Y-O]- as a phenylene ether-type repeating unit consisting of an aromatic divalent group Y and an oxygen atom O. One type of polyphenylene ether may be used for the adhesive composition of the embodiment, or two or more types of polyphenylene ethers may be used in combination.

The aromatic divalent group Y is an unsubstituted phenylene group (—C ₆ H ₄ —) or a substituted phenylene group having 1 to 4 substituents on the phenylene group. A phenylene group represented by Y is preferably a p-phenylene group. The phenylene group represented by Y may have one or more substituents selected from halogen atoms such as fluorine and chlorine; alkyl groups having 1 to 6 carbon atoms, haloalkyl groups, phenyl groups and the like. Specific examples of the substituted phenylene group represented by Y include a 2,6-dimethyl-p-phenylene group, a 2,3,6-trimethyl-p-phenylene group, and a 2,3,5,6-tetramethyl-p-phenylene group. and the like.

The polyphenylene ether preferably has an unsaturated hydrocarbon group on at least one end of the molecule, and more preferably has an unsaturated hydrocarbon group on both ends of the molecule. Examples of unsaturated hydrocarbon groups include vinyl groups, allyl groups, propenyl groups, isopropenyl groups, and butenyl groups. Polyphenylene ether is preferably a compound represented by the following structural formula (I) or structural formula (II).

VW-[X] _a -[OY] _b -OZO-[YO] _c -[X] _d -WV (I)

VW-[X] _a -[OY] _e -O-[X] _d -WV (II)

In Structural Formula (I) or Structural Formula (II), V is an unsaturated hydrocarbon group such as a vinyl group. Two Ws are each independently an unsubstituted phenylene group (—C ₆ H ₄ —) or a substituted phenylene group having 1 to 4 substituents on the phenylene group. The phenylene group represented by W may be any of p-phenylene group, m-phenylene group and o-phenylene group. The phenylene group represented by W may have one or more substituents selected from halogen atoms such as fluorine and chlorine; alkyl groups having 1 to 6 carbon atoms, haloalkyl groups, phenyl groups and the like.

X is an organic group having 1 or more carbon atoms. The organic group represented by X may contain an oxygen atom, a sulfur atom or a halogen atom. The organic group represented by X is preferably a divalent organic group having 1 to 6 carbon atoms, and may be, for example, an aliphatic hydrocarbon group such as an alkylene group. X may be a methylene group ( _--CH.sub.2-- ). When V is a vinyl group, W is a p-phenylene group, and X is a methylene group, VWX- may be a p-vinylbenzyl group.

When X contains an oxygen atom, a sulfur atom or a halogen atom, those atoms may be a hydroxyl group, a keto group, an ether bond, a thioether, a fluoro group, a chloro group, etc., but -X- or -X-O- Y- does not contain a peroxide bond (-O-O-). a and d are 0 or 1 respectively. When a is 0, -[X] _a - is a single bond. When d is 0, -[X] _d - is a single bond.

Each Y is independently an unsubstituted phenylene group (—C ₆ H ₄ —) or a substituted phenylene group having 1 to 4 substituents on the phenylene group. In Structural Formula (I), each of b and c is preferably an integer of 0-100, more preferably an integer of 0-20. At least one of b and c is preferably non-zero. When b is 0, -[OY] _b - is a single bond. When c is 0, -[YO] _c - is a single bond. In Structural Formula (II), e is preferably an integer of 1-200, more preferably an integer of 2-40.

In Structural Formula (I), -Z- is preferably a divalent group represented by -UAU-. Here, U is an unsubstituted phenylene group ( _{--C.sub.6H.sub.4--} ) or a substituted phenylene group having 1 to 4 substituents on the _phenylene group. A phenylene group represented by U is preferably a p-phenylene group. The phenylene group represented by U may have one or more substituents selected from halogen atoms such as fluorine and chlorine; alkyl groups having 1 to 6 carbon atoms, haloalkyl groups, phenyl groups and the like.

A is a single bond or a hydrocarbon group having 1 to 20 carbon atoms. The hydrocarbon group represented by A may be linear, branched or cyclic. When A is a hydrocarbon group, it is preferably a divalent hydrocarbon group having 1 to 20 carbon atoms, and may be, for example, an aliphatic hydrocarbon group such as an alkylene group. When A is a single bond, -Z- has a biphenyl skeleton represented by -UU-.

Although the method for producing the polyphenylene ether represented by Structural Formula (I) or Structural Formula (II) is not particularly limited, examples thereof include the following methods. First, a dihydric phenol compound represented by HO-Z-OH or HO-Y-OH is oxidatively coupled with a monohydric phenol compound represented by HO-Y-H or HY-OH to form a skeleton portion. Generate. Furthermore, the terminal hydroxyl group of the skeleton is etherified to introduce a VW-[X] _a - moiety.

The combined use of polyphenylene ether and a styrenic thermoplastic elastomer contributes to improving the thermosetting properties, heat resistance and low dielectric properties of the adhesive composition. The ratio of polyphenylene ether to 100 parts by weight of the styrene-based elastomer is preferably 25 to 75 parts by weight. If the proportion of polyphenylene ether is less than 25 parts by weight, the heat resistance of the adhesive composition may deteriorate. If the proportion of polyphenylene ether exceeds 75 parts by weight, the adhesive strength of the adhesive composition may decrease.

The polyphenylene ether preferably has a number average molecular weight in the range of 500-3000. Number average molecular weights can be determined by gel permeation chromatography with polystyrene standards. A polyphenylene ether having a number average molecular weight of 500 or more is preferable because it is easy to suppress outflow due to a decrease in viscosity. Polyphenylene ether having a number average molecular weight of 3,000 or less is preferable because the solubility is improved.

<Curing agent>
The adhesive composition of the embodiment contains a curing agent. This curing agent is a curing agent having unsaturated bonds or peroxide bonds. Examples of unsaturated bonds include maleimide groups, acryloyl groups, methacryloyl groups, vinyl ether groups, allyl ether groups, and the like. The adhesive composition of the embodiment may use one curing agent or two or more curing agents in combination.

Curing agents with peroxide bonds include peroxides (R—O—O—R′), hydroperoxides (R—O—O—H), acyl peroxides (R—CO—O—O—CO—R '), peroxide esters (R—CO—O—O—R′), peracids (R—CO—O—O—H), and the like. In these general formulas, R and R' are each independently an organic group such as an alkyl group. A curing agent having a peroxide bond can cure a compound having an unsaturated bond by generating radicals. R and R' each independently include a hydrocarbon group having 1 to 20 carbon atoms, an aliphatic group, an alicyclic group, an aromatic group, and the like.

A maleimide-based compound having a maleimide group is preferable as the curing agent having an unsaturated bond. A maleimide-based compound can be heat-cured by itself, but can be heat-cured even at a lower temperature by coexisting it with another compound having an unsaturated bond. The maleimide-based compound preferably has two or more maleimide groups in the molecule. As the maleimide compound, compounds represented by the following structural formulas (i) to (iv) are preferred.

MPBPM (i)

M-P-O-D-O-P-M (ii)

MP-CH ₂ -[P(M)-CH ₂ ] _n -PM (iii)

M-E-M (iv)

In structural formulas (i)-(iv), M is a maleimido group. A maleimido group is a monovalent group that is attached to another atom (such as the carbon atom of P or E) at the nitrogen atom of the maleimide.

In structural formulas (i) to (iii), each P is independently an unsubstituted phenylene group (—C ₆ H ₄ —) or a substituted phenylene group having 1 to 4 substituents on the phenylene group. . The phenylene group represented by P may be p-phenylene group, m-phenylene group or o-phenylene group. The phenylene group represented by P may have one or more substituents selected from alkyl groups having 1 to 6 carbon atoms. The alkyl group having 1 to 6 carbon atoms includes methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group and the like. Specific examples of the substituted phenylene group represented by P include 2,6-dimethyl-p-phenylene group and 2-ethyl-6-methyl-p-phenylene group.

In Structural Formula (i), B is a single bond, a divalent hydrocarbon group having 1 to 20 carbon atoms, or an oxygen atom. Preferably, B is a divalent aliphatic saturated hydrocarbon group having 1 to 4 carbon atoms. Specific examples of B include a methylene group ( _--CH.sub.2-- ), an ethylidene group [--CH( _CH.sub.3 )--] _, a propylidene group [--CH( _{CH.sub.2CH.sub.3} )--], an isopropylidene group [--C( CH ₃ ) ₂ —], p-phenylenediisopropylidene group, m-phenylenediisopropylidene group, cyclohexylidene group, phenylmethylene group [—CH(C ₆ H ₅ )-], naphthylmethylene group, 1-phenyl Examples include ethylidene group, m-phenylene group, p-phenylene group and the like.

In Structural Formula (ii), D is a divalent hydrocarbon group having 1 to 20 carbon atoms. -D- may be a divalent group represented by -GKG-. G is an unsubstituted phenylene group (—C ₆ H ₄ —) or a substituted phenylene group having 1 to 4 substituents on the phenylene group. The phenylene group represented by G may have one or more substituents selected from alkyl groups having 1 to 4 carbon atoms. K is a divalent aliphatic saturated hydrocarbon group having 1 to 4 carbon atoms. Specific examples of D include p-phenylene group, m-phenylene group, methylenedi-p-phenylene group, isopropylidenedi-p-phenylene group and the like. When K is an alkylene group and G is a phenylene group, -GKG- is an alkylenediphenylene group.

In Structural Formula (iii), P(M) is a phenylene group having at least a maleimide group as a substituent. P(M) may be a phenylene group [-C ₆ H ₃ (M)-] having only a maleimide group as a substituent, or a substituted phenylene group having 1 to 3 other substituents in addition to a maleimide group to the phenylene group. good. Examples of substituents other than maleimido groups in P(M) include alkyl groups having 1 to 6 carbon atoms. n is an integer from 1 to 20;

In structural formula (iv), E is a divalent aliphatic hydrocarbon group having 1 to 20 carbon atoms. Examples of E include an ethylene group (--CH ₂ CH ₂ --), a trimethylene group (--CH ₂ CH ₂ CH ₂ --), a tetramethylene group (--CH ₂ CH ₂ CH ₂ CH ₂ --), and a hexamethylene group ( —CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ —), 2,2,4-trimethylhexamethylene group [—CH ₂ C(CH ₃ ) ₂ CH ₂ CH(CH ₃ )CH ₂ CH ₂ —], etc. is mentioned.

The ratio of the curing agent having an unsaturated bond or a peroxide bond to 100 parts by weight of the styrene-based elastomer is preferably 0.1 to 2 parts by weight. If the proportion of the curing agent is less than 0.1 parts by weight, the heat resistance of the adhesive composition may deteriorate. If the amount of curing agent is too small, resin flow may become excessive. If the proportion of the curing agent exceeds 2 parts by weight, the heat resistance, adhesive strength and low dielectric properties of the adhesive composition may deteriorate. If the amount of the curing agent is too large, an excessive amount of low-molecular-weight outgassing may be generated and the heat resistance of the adhesive composition may be lowered.

<Acid-modified elastomer>
The adhesive composition of the embodiment contains an acid-modified elastomer. The acid-modified elastomer is a component different from the styrene-based elastomer that is not acid-modified. The adhesive composition of the embodiment may use one type of acid-modified elastomer, or may use two or more types of acid-modified elastomers in combination.

In order to impart elasticity as an elastomer to the acid-modified elastomer, for example, a soft segment and a hard segment may be provided in the molecular structure. Alternatively, a physical cross-linked structure may be provided that cross-links the molecular structure at room temperature (eg, 5 to 35° C.) and reduces cross-linkability and increases fluidity at higher temperatures. Alternatively, it may be a polymer blend in which a rubber component is dispersed in a resin component. In order to contribute to the low dielectric properties of the adhesive composition, it is preferably an acid-modified elastomer obtained by modifying a low-polarity thermoplastic elastomer. The acid-modified elastomer is preferably at least one selected from acid-modified styrene-based elastomers and acid-modified olefin-based elastomers.

An acid-modified styrene-based elastomer is a material in which a styrene-based elastomer is modified with an acid functional group. Specific examples of the acid-modified styrene elastomer are selected from acid-modified styrene-ethylene-butylene-styrene, acid-modified styrene-ethylene-propylene-styrene, acid-modified styrene-butylene-styrene, and acid-modified styrene-isoprene-styrene. At least 1 type is mentioned. The weight ratio of styrene units in the acid-modified styrene elastomer is preferably 10 to 40 wt%, more preferably 10 to 30 wt%, and even more preferably 10 to 25 wt%, relative to the total weight of the acid-modified styrene elastomer. .

An acid-modified olefin elastomer is a material obtained by modifying a polyolefin resin, which is a thermoplastic elastomer, with an acid functional group. At least one selected from ethylene, propylene, butene, isobutene, butadiene, isoprene and the like can be used as the olefin used as a monomer for the acid-modified polyolefin resin. The polyolefin resin may be a homopolymer containing one olefin or a copolymer containing two or more olefins.

Specific examples of acid-modified polyolefin resins include acid-modified polypropylene and acid-modified polyethylene. The acid-modified polypropylene may be a propylene homopolymer or a copolymer of propylene and ethylene, butene, isobutene, butadiene, isoprene, or the like. The weight ratio of propylene units in the acid-modified polypropylene is preferably 50 to 98% by weight with respect to the total weight of the modified polypropylene.

The acid functional groups used for modifying the acid-modified elastomer are preferably carboxy groups or acid anhydride groups. Examples of modifying monomers used for acid modification of acid-modified elastomers include α,β-unsaturated carboxylic acids and acid anhydrides thereof. Specific examples of α,β-unsaturated carboxylic acids include unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid and crotonic acid; maleic acid, fumaric acid, citraconic acid, mesaconic acid, itaconic acid, tetrahydrophthalic acid, norbornene Unsaturated dicarboxylic acids such as dicarboxylic acids; aconitic acid; Specific examples of α,β-unsaturated carboxylic acid anhydrides include maleic anhydride, citraconic anhydride, itaconic anhydride, tetrahydrophthalic anhydride, norbornene dicarboxylic anhydride, and aconitic anhydride.

The modifying monomer may be copolymerized on the main chain of the thermoplastic elastomer or may be grafted on the side chains of the thermoplastic elastomer. In grafting, for example, an unmodified thermoplastic elastomer and a modified monomer may be reacted in the presence of a radical initiator. Radical initiators include aromatic peroxides such as benzoyl peroxide and dicumyl peroxide; aliphatic peroxides such as dilauroyl peroxide and di-t-butyl peroxide; and hydroperoxides such as cumene hydroperoxide.

The weight ratio of modified monomer units in the acid-modified elastomer is preferably 0.1 to 20% by weight with respect to the total weight of the acid-modified elastomer. The weight average molecular weight (Mw) of the acid-modified elastomer is not particularly limited, but is, for example, 10,000 to 500,000, more preferably 30,000 to 250,000.

The ratio of the acid-modified elastomer to 100 parts by weight of the styrene-based elastomer is preferably 20 to 80 parts by weight. If the proportion of the acid-modified elastomer is less than 20 parts by weight, the adhesive strength of the adhesive composition may decrease. If the proportion of the acid-modified elastomer exceeds 80 parts by weight, the resin flow of the adhesive composition may deteriorate.

<Epoxy resin>
The adhesive composition of the embodiment contains an epoxy resin. Epoxy resins are compounds with epoxy groups capable of reacting with carboxy groups. For this reason, the epoxy resin reacts with the acid-modified elastomer and can exhibit high adhesiveness to the adherend and heat resistance of the cured product.

Examples of epoxy resins include bisphenol-type epoxy resins, glycidyl ethers of polyhydric alcohols or polyhydric phenols, glycidyl esters of polycarboxylic acids, glycidylamine-type epoxy resins, and the like. The adhesive composition of the embodiment may use one type of epoxy resin, or two or more types of epoxy resins may be used in combination.

Bisphenol type epoxy resins include bisphenol A type epoxy resins, bisphenol F type epoxy resins, hydrogenated bisphenol A type epoxy resins, and the like.
Glycidyl ether epoxy resins include ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, and pentaerythritol. Examples include tetraglycidyl ether, tetraphenylglycidyl ether ethane, triphenylglycidyl ether ethane, polyglycidyl ether of sorbitol, and polyglycidyl ether of polyglycerin.

Glycidyl ester epoxy resins include diglycidyl phthalate, diglycidyl isophthalate, diglycidyl terephthalate, glycidyl p-hydroxybenzoate, diglycidyl tetrahydrophthalate, diglycidyl succinate, and adipic acid. Examples include diglycidyl ester, diglycidyl sebacate, and triglycidyl trimellitate.
Glycidylamine type epoxy resins include triglycidyl isocyanurate, tetraglycidyldiaminodiphenylmethane, tetraglycidylmeta-xylylenediamine, and the like.

Other epoxy resins include non-cyclic aliphatic epoxy resins such as epoxidized polybutadiene and epoxidized soybean oil; Alicyclic epoxy resins such as cyclopentadiene epoxy resins; polycyclic aromatic epoxy resins such as naphthalene epoxy resins and anthracene epoxy resins; flame-retardant epoxy resins such as brominated epoxy resins and phosphorus-containing epoxy resins; mentioned.

The epoxy resin is preferably a compound having two or more epoxy groups in the molecule. When the reaction between the epoxy group and the carboxy group occurs at two or more sites, the epoxy resin forms a crosslinked structure with the acid-modified polyolefin resin, and high heat resistance can be imparted to the cured product of the adhesive composition.

The ratio of the epoxy resin to 50 parts by weight of the acid-modified elastomer is preferably 1 to 10 parts by weight. If the proportion of the epoxy resin is less than 1 part by weight, the heat resistance of the adhesive composition may deteriorate. If the proportion of the epoxy resin exceeds 10 parts by weight, the adhesive strength and resin flow of the adhesive composition may be reduced.

<Curing agent for epoxy resin>
The adhesive composition of the embodiment contains an epoxy resin curing agent. The curing agent for epoxy resin is a component different from the curing agent having the unsaturated bond or the peroxide bond. The adhesive composition of the embodiment may use one epoxy resin curing agent, or two or more epoxy resin curing agents in combination. Curing agents for epoxy resins include amine-based curing agents, acid anhydride-based curing agents, tertiary amine-based curing agents, imidazole-based curing agents, polyamide resins, dicyandiamide, and boron trifluoride.

Amine-based curing agents, acid anhydride-based curing agents, and the like are curing agents having active hydrogen capable of reacting with epoxy groups. Examples of amine curing agents include melamine resins such as methylated melamine resins, butylated melamine resins and benzoguanamine resins, and aromatic amines such as dicyandiamide and 4,4'-diphenyldiaminosulfone. Examples of acid anhydride-based curing agents include aromatic acid anhydrides, aliphatic acid anhydrides, and alicyclic acid anhydrides.

A tertiary amine-based curing agent, an imidazole-based curing agent, and the like can accelerate the reaction between the epoxy resin and the compound having active hydrogen. Tertiary amine curing agents include benzyldimethylamine, 2-(dimethylaminomethyl)phenol, 2,4,6-tris(dimethylaminomethyl)phenol, tetramethylguanidine, triethanolamine, N,N'- dimethylpiperazine, triethylenediamine, 1,8-diazabicyclo[5.4.0]undecene and the like.

Examples of imidazole curing accelerators include 2-methylimidazole, 1,2-dimethylimidazole, 2-methyl-4-ethylimidazole, 2-undecylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2- phenylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-bis(hydroxymethyl)imidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole and the like.

Polyamide resins include polyamidoamine compounds produced by condensing a dimer acid obtained by dimerization of an unsaturated fatty acid with a polyamine.
Dicyandiamide may be used in combination with basic compounds such as tertiary amines, imidazoles and aromatic amines.
Boron trifluoride (BF ₃ ), like metal halides such as ZnCl ₂ , SnCl ₄ , FeCl ₃ and AlCl ₃ , becomes a Lewis acid and is used as a cationic polymerization catalyst for epoxy groups. Boron trifluoride may be used as an amine complex.

The ratio of the epoxy resin curing agent to 50 parts by weight of the acid-modified elastomer is preferably 0.01 to 1.5 parts by weight. If the proportion of the curing agent for epoxy resin is less than 0.01 parts by weight, the heat resistance of the adhesive composition may deteriorate. If the proportion of the curing agent for epoxy resin exceeds 1.5 parts by weight, an excessive amount of low-molecular-weight outgassing may occur, and the heat resistance of the adhesive composition may decrease.

<Adhesive composition>
The adhesive composition of the embodiment comprises, as essential components, a non-acid-modified styrene elastomer, a polyphenylene ether, a curing agent having an unsaturated bond or a peroxide bond, an acid-modified elastomer, an epoxy resin, and a curing agent for epoxy resin.

Adhesion with an excellent balance of adhesive strength and resin flow to various adherends by using both an adhesive based on a styrene elastomer that is not acid-modified and an adhesive based on an acid-modified elastomer. agent composition can be realized.

Optional components of the adhesive composition include fillers, flame retardants, reaction accelerators, cross-linking agents, polymerization inhibitors, coupling agents, thermosetting resins, thermoplastic resins, dyes, pigments, thickeners, lubricants, Antifoaming agents, ultraviolet absorbers, and the like are included. Two or more optional ingredients may be added.

The adhesive compositions of embodiments have low dielectric properties. The dielectric constant (ε) of the adhesive composition is preferably 2.0 to 3.0, more preferably 2.0 to 2.5. Furthermore, the dielectric loss tangent (tan δ) of the adhesive composition is preferably 0.005 or less. The dielectric properties of the adhesive composition may be measured on the adhesive composition in a dry state or on a cured layer after curing the adhesive composition. The adhesive composition before curing may be in an uncured state such as A-stage or in a semi-cured state such as B-stage.

The adhesive composition of the embodiment may be formed into a film form by coating, drying, etc. from a liquid adhesive liquid in which each component is dissolved or dispersed in a solvent. The adhesive liquid may be either a solution or a dispersion.

The solvent for the adhesive liquid is not particularly limited, but hydrocarbon solvents such as benzene, toluene and xylene; glycol solvents such as ethylene glycol ethyl ether, propylene glycol dimethyl ether and ethylene glycol monomethyl ether acetate; Ether-based solvents; Ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and cyclopentanone; Ester-based solvents such as ethyl acetate, butyl acetate, and γ-butyrolactone; N,N-dimethylformamide, N,N-dimethyl Amide solvents such as acetamide and N-methyl-2-pyrrolidone; sulfur-containing solvents such as dimethylsulfoxide; chlorine solvents such as dichloromethane, chloroform and 1,2-dichloroethane; .

Examples of the method for preparing the adhesive liquid include a method in which each component of the adhesive composition and a solvent are added to a container equipped with a stirring device and stirred. If you want to shorten the dissolution time, you may heat it. The solid content of the adhesive liquid is not particularly limited, but is, for example, 10 to 50% by weight, preferably 15 to 40% by weight.

In order to prepare an adhesive film in which an adhesive composition is formed from an adhesive liquid, a method of applying the adhesive liquid to a coating substrate and drying the solvent from the adhesive liquid on the coating substrate can be mentioned. . The coating substrate is not particularly limited as long as it is a material having a surface capable of receiving the applied adhesive liquid, but plastic film, metal foil, paper, woven fabric, non-woven fabric, or a laminate containing these is mentioned. The dried adhesive film may be laminated and integrated with the coating substrate. The coated surface of the coating substrate may be subjected to a release treatment to form the adhesive film releasable from the coating substrate.

The method of applying the adhesive liquid is not particularly limited, but air doctor coating, bar coating, blade coating, knife coating, reverse coating, transfer roll coating, gravure roll coating, kiss coating, cast coating, spray coating, slot orifice coating, Coating methods such as calender coating, dam coating, dip coating and die coating, and printing methods such as gravure printing, intaglio printing, screen printing and stencil printing can be used.

The drying method of the adhesive liquid is not particularly limited, but can be appropriately set according to the type of solvent, the thickness of the adhesive liquid, the area, and the like. The drying temperature is, for example, 60 to 150°C. The drying time is, for example, 1 to 60 minutes, more preferably 1 to 30 minutes, still more preferably 1 to 10 minutes. The shorter the drying time, the higher the productivity, which is preferable. The coating substrate may be a sheet having a flat surface or a roll that can be wound up.

When the adhesive liquid is applied to the roll-shaped coating substrate, the adhesive liquid is continuously applied on the flat part of the coating substrate while pulling out the coating substrate from the roll and conveying it in the length direction. You can apply it. The adhesive liquid applied to the coating substrate may be sequentially dried at a predetermined drying temperature for a predetermined drying time, and then wound into a roll again. A release treatment may be applied to the surface of the coating substrate opposite to the surface to which the adhesive liquid is applied. A release paper or a release film that has been subjected to a release treatment may be superimposed on the dried adhesive film to protect the adhesive film.

A laminate in which the adhesive composition of the embodiment is laminated on a release sheet can be used as a bonding sheet. The release sheet may be a release film mainly composed of a plastic film or a release paper mainly composed of paper. Although the thickness of the release sheet is not particularly limited, it is preferably a release film with a thickness of 10 to 100 μm or a release paper with a thickness of 50 to 200 μm.

The material of the release film is not particularly limited, but examples include polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polyethylene terephthalate, polyethylene naphthalate, and the like. The material of the release paper is not particularly limited, but examples thereof include polyethylene-coated paper and polypropylene-coated paper. The release sheet may be subjected to release treatment using a release agent such as silicone. Although the thickness of the adhesive film used for the bonding sheet can be set arbitrarily, it is preferably 5 to 50 μm, more preferably 5 to 25 μm in dry state.

A release sheet may be laminated on at least one side of the adhesive film. By superimposing the adhesive film from which the release sheet has been removed on the adherend and curing the adhesive film, the adherend can be adhered. An adhesive film with a substrate may be produced by laminating a substrate such as copper foil on one side of the adhesive film. The base material and the adherend can be bonded by laying the adherend on the opposite side of the base material of the adhesive film with the base material and curing the adhesive film.

Among adhesive films with a substrate, those using a copper foil as a substrate can be used as an adhesive film with a copper foil (FRCC: Flexible Resin Coated Copper). The thickness of the copper foil is preferably 5-50 μm, more preferably 9-25 μm. Although the thickness of the adhesive film used for FRCC can be set arbitrarily, it is preferably 1 to 50 μm, more preferably 1 to 25 μm in dry state.

Among adhesive films with a substrate, those using an electrically insulating film as a substrate can be used as a coverlay film. It is preferable that the electrically insulating film have heat resistance capable of coping with heat curing of the adhesive film. The material of the electrically insulating film is not particularly limited, but polyimide, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyparabanic acid, polyether ether ketone, polyphenylene sulfide, liquid crystal polymer (LCP), syndiotactic polystyrene, polycarbonate. etc. The polyimide may be modified polyimide (mPI). Examples of modified polyimides include, but are not limited to, isocyanate-modified polyimides, acid-modified polyimides, olefin-modified polyimides, polycarbonate-modified polyimides, silicone-modified polyimides, polysiloxane-modified polyimides, epoxy-modified polyimides, polyester-modified polyimides, and urethane-modified polyimides. .

Although the thickness of the electrically insulating film can be set arbitrarily, it is, for example, 1 to 50 μm, preferably 3 to 38 μm, particularly preferably 5 to 25 μm. For the purpose of increasing the strength of adhesion with the adhesive composition, the surface of the electrically insulating film may be subjected to surface treatment such as chemical solution treatment, plasma treatment, corona discharge treatment, sandblast treatment, and the like. Although the thickness of the adhesive film used for the coverlay film can be set arbitrarily, it is preferably 5 to 50 μm, more preferably 5 to 38 μm, even more preferably 5 to 25 μm in a dry state.

Among adhesive films with a substrate, those using a copper clad laminate (CCL) as a substrate can be used as a copper clad laminate with an adhesive. For example, a copper foil may be laminated on one surface of the electrically insulating film, and an adhesive film may be laminated on the other surface of the electrically insulating film. If the copper-clad laminate has flexibility, it can be used to produce a flexible printed wiring board.

From the viewpoint of obtaining an adhesive composition having excellent storage stability and a long shelf life, the adhesive film of the embodiment preferably has a large resin flow after storage of the adhesive film at 40° C. for 7 days. When the resin flow is large, the shelf life is excellent, and the embedding of irregularities such as wiring is excellent. However, if the resin flow is too large, the adhesive may overflow from the edge of the substrate, etc., and the thickness of the adhesive required for adhesive strength and solder heat resistance may not be ensured. A suitable range of resin flow is preferably 0.05 to 0.35 mm, more preferably 0.1 to 0.3 mm.

<Laminated film>
By curing the adhesive composition of the embodiment on a substrate, a laminated film having a cured layer of the adhesive composition can be produced. A method for curing the adhesive composition is not particularly limited, but includes, for example, a method of heating to a temperature of 150 to 180°C. The heating time is, for example, 20 minutes to 5 hours, and may be 30 minutes to 2 hours. Heating methods include, for example, hot air circulation ovens, presses, and autoclaves.

The base material of the laminated film is not particularly limited, but includes plastic films, metal foils, papers, woven fabrics, non-woven fabrics, and laminates containing these. The plastic film may be the electrically insulating film described above. The metal foil may be the copper foil described above. The substrate of the laminated film may be a plastic film or a composite film mainly composed of plastic. A laminated film substrate may be used as the coating substrate described above. When laminating the cured layer on a substrate different from the coating substrate, for example, an adhesive film formed from the adhesive composition before curing is transferred from the coating substrate onto the substrate, and the adhesive film is formed on the substrate. It may be cured.

<Printed wiring board>
The printed wiring board of the embodiment can be produced by including the cured layer of the adhesive composition or the laminated film. The printed wiring board may be a printed circuit board in which circuits are connected by circuit parts such as printed parts and mounting parts. It may be a printed wiring board having wiring before circuit components are formed. The wiring may be formed by patterning the copper foil of the laminated film by etching or the like. Copper foil may be used to form parts or functions such as antennas integrally with the wiring.

The printed wiring board may be a rigid printed wiring board having a rigid insulating substrate. The printed wiring board may be a flexible printed wiring board having a flexible insulating substrate. The insulating substrate may be a flex-rigid printed wiring board having a rigid portion and a flexible portion. The flexible insulating substrate may be the electrically insulating film described above. An insulating substrate having a rigid portion and a flexible portion may be formed by laminating a rigid insulating material on a partial region of the electrically insulating film.

Since the adhesive composition of the embodiment has a low dielectric constant, it is suitable as a material for high frequency printed wiring boards. Since the adhesive composition of the embodiment has excellent storage stability, it can be used as an adhesive used for producing a laminated film having a cured layer in which the adhesive is cured, and a printed wiring board provided with the laminated film. preferred.

Although the present invention has been described above based on preferred embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

EXAMPLES The present invention will be specifically described below with reference to examples.

(Preparation of adhesive solution)
Each component having the composition shown in Tables 1 to 4 below was charged into a container, and all components were dissolved using a solvent. The resulting liquid was filtered through a nylon mesh (wire diameter: 30 μm, 255 mesh) to obtain an adhesive solution. During preparation of the adhesive solution, the temperature of the solution was controlled so as not to exceed 30°C.

"Styrenic" shown in Tables 1 to 4 is a styrenic elastomer that has not been acid-modified.
"PPE" as shown in Tables 1-4 is polyphenylene ether.
"Peroxide", as shown in Tables 1-4, is a curing agent with peroxide linkages.
"Acid-modified" shown in Tables 1-4 are acid-modified elastomers.
"Epoxy resin" shown in Tables 1-4 is an epoxy resin.
"Imidazole" shown in Tables 1 to 4 is an imidazole curing agent for epoxy resins.

(Preparation of adhesive film)
An applicator was used to apply the adhesive solution to a release-treated polyethylene terephthalate film (silicone treatment, thickness 38 μm) so that the thickness after drying was 25 μm. Then, it was dried in a ventilation oven set at 100° C. for 5 minutes to obtain an adhesive film having a thickness of 25 μm.

(Measurement of adhesive strength to LCP)
Using a roll laminator, the adhesive film was laminated on a 25 μm-thick LCP film (trade name: Vecstar (registered trademark) CT-Z, manufactured by Kuraray Co., Ltd.). Working conditions were a roll temperature of 120° C., a pressure of 30 N/cm, and a speed of 0.5 m/min. Next, the same LCP films as above were laminated to obtain a laminate in which two LCP films were bonded together via an adhesive film. The laminate was heat-pressed under the conditions of 160°C x 0.5 MPa x 2 minutes, then heat-cured in a ventilation oven at 180°C x 1 hour, and then cut into 10 mm x 100 mm pieces to measure adhesive strength to LCP. A sample for Using a universal tensile tester (manufactured by Orientec Co., Ltd.), the LCP film of the measurement sample was peeled off in the direction of 90° at a tensile speed of 50 mm/min to measure the adhesive strength.

(Measurement of adhesive strength to mPI)
The adhesive film was laminated to a 50 μm thick mPI film using a roll laminator. Working conditions were a roll temperature of 120° C., a pressure of 30 N/cm, and a speed of 0.5 m/min. Next, the same mPI films as above were laminated to obtain a laminate in which two mPI films were laminated via an adhesive film. The laminate was heat-pressed under the conditions of 160°C x 0.5 MPa x 2 minutes, then heat-cured in a ventilation oven at 180°C x 1 hour, and then cut into 10 mm x 100 mm pieces to measure the adhesive strength to mPI. A sample for Using a universal tensile tester (manufactured by Orientec Co., Ltd.), the mPI film of the measurement sample was peeled off in the direction of 90° at a tensile speed of 50 mm/min to measure the adhesive strength.

(Measurement of adhesive strength to Cu)
An adhesive film was laminated on a copper foil (trade name: FQ-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) with a thickness of 18 μm using a roll laminator. Working conditions were a roll temperature of 120° C., a pressure of 30 N/cm, and a speed of 0.5 m/min. Next, the same copper foils as above were laminated to obtain a laminate in which the shiny surfaces of the two copper foils were bonded together via an adhesive film. The laminate was heat-pressed under the conditions of 160°C x 0.5 MPa x 2 minutes, then heat-cured in a ventilation oven at 180°C x 1 hour, and then cut into 10 mm x 100 mm pieces to measure the adhesion strength to Cu. A sample for Using a universal tensile tester (manufactured by Orientec Co., Ltd.), the copper foil of the measurement sample was peeled off in the direction of 90° at a tensile speed of 50 mm/min to measure the adhesive strength.

(Measurement of solder heat resistance)
A sample for measurement of solder heat resistance temperature using LCP was prepared in the same manner as the sample for measurement of adhesive strength to LCP, except that the cut size of the sample for measurement was 25 mm × 25 mm. In addition, a sample for measurement of solder heat resistance temperature using Cu was produced in the same manner as the sample for measurement of adhesive strength to Cu, except that the cut size of the sample for measurement was 25 mm × 25 mm. Each sample for measurement was subjected to humidity conditioning treatment under conditions of 20° C.×65% RH×96 hours, and then floated in a solder bath at a predetermined temperature for 60 seconds. Both the measurement sample using LCP and the measurement sample using Cu were evaluated to have solder heat resistance at the relevant temperature when abnormalities such as swelling, tearing, and turning up did not occur during the 60-second float. . If any abnormality occurred in the measurement sample using LCP or Cu, it was evaluated as having no solder heat resistance at that temperature. The temperature of the solder bath was set to 260° C., 270° C., 280° C., 290° C., and 300° C., and the highest temperature with solder heat resistance was measured.

(Measurement of dielectric properties)
Adhesive films with a thickness of 25 μm were successively laminated using a roll laminator to obtain an adhesive laminate with a thickness of 200 μm. With the release-treated polyethylene terephthalate film superimposed on both sides of the adhesive laminate, it was cured by heating in a ventilation oven at 180° C. for 1 hour, then cut into 2 mm×50 mm pieces and measured for dielectric properties. A sample for The release-treated polyethylene terephthalate film was removed immediately before the measurement, and the dielectric constant (ε) and dielectric loss tangent (tan δ) at 10 GHz were measured for the adhesive laminate by the cavity resonator perturbation method.

(Measurement of resin flow)
The laminate obtained by laminating the adhesive film on the release-treated polyethylene terephthalate film was stored in an environment of 40° C. for 7 days. After being stored at 40° C. for 7 days, the laminate was punched with a punch having a punch hole diameter of 6 mmφ, and a roll laminator was used to apply a 25 μm-thick LCP film (trade name: Vecstar (registered trademark) CT). -Z. manufactured by Kuraray Co., Ltd.). The operating conditions of the roll laminator were a roll temperature of 120° C., a pressure of 30 N/cm, and a speed of 0.5 m/min. Next, a copper foil (trade name: FQ-VLP, manufactured by Mitsui Mining & Smelting Co., Ltd.) having a thickness of 18 μm is laminated using a roll laminator on the side of the adhesive film from which the release-treated polyethylene terephthalate film has been peeled off. Then, a sample for measurement of resin flow was obtained, which consisted of a laminate in which an LCP film and a copper foil were bonded together via an adhesive film having punched holes. The center of the punched hole portion of the measurement sample was marked, a cross was drawn, and the diameter of the punched hole (diameter before hot pressing: d0) was measured with a microscope. After the measurement sample was heat-pressed under the conditions of 160° C.×0.5 MPa×2 minutes, the diameter of the punch hole of the measurement sample (diameter after hot-pressing: d1) was measured with a microscope. Resin flow (mm) was obtained by subtracting the diameter (d1) after hot-pressing from the diameter (d0) before hot-pressing, and half {(d0-d1)/2}.

(Measurement result)
Tables 1 to 4 show measurement results for each of the above items.

The adhesive films of Examples 1 to 19 have high adhesion to both LCP films and mPI films, which are preferably used as electrical insulating films for printed wiring boards, and copper foils, which are preferably used as wiring materials. It exhibited strength, had high solder heat resistance, and had low dielectric properties. In addition, regarding the storage stability of the adhesive composition, the adhesive films of Examples 1 to 19 had an appropriate range of resin flow even after being stored at 40°C for 7 days, and had a long shelf life. It has been shown.

The adhesive film of Comparative Example 1 had a small resin flow, and was inferior in embedding in irregularities such as wiring. This is probably because the adhesive tends to harden when the three components of the acid-modified elastomer, the epoxy resin, and the curing agent for the epoxy resin are cured.

The adhesive film of Comparative Example 2 had low adhesive strength to the mPI film and copper foil. This is presumably because the affinity of mPI and other adherends decreases when the three components of the non-acid-modified styrene elastomer, the polyphenylene ether, and the curing agent having a peroxide bond are cured.

The adhesive film of Comparative Example 3 had low adhesive strength to the mPI film and copper foil. This is probably because the ratio of the curing agent to the styrene-based elastomer is too high.

With the adhesive film of Comparative Example 4, the resin flow was too large, and the adhesive easily overflowed. This is probably because the ratio of the curing agent to the styrene-based elastomer is too small.

Claims (7)

A styrene-based elastomer that is not acid-modified, a polyphenylene ether, a curing agent having an unsaturated bond or a peroxide bond, an acid-modified elastomer, an epoxy resin, and an epoxy resin curing agent, wherein the styrene-based An adhesive composition characterized in that the proportion of said curing agent having an unsaturated bond or a peroxide bond is 0.1 to 2 parts by weight with respect to 100 parts by weight of elastomer. 2. The adhesive composition according to claim 1, wherein a ratio of said epoxy resin to 50 parts by weight of said acid-modified elastomer is 1 to 10 parts by weight. 3. The adhesive composition according to claim 1, wherein the proportion of said polyphenylene ether is 25 to 75 parts by weight with respect to 100 parts by weight of said styrene elastomer. 4. The adhesive composition according to any one of claims 1 to 3, wherein the proportion of said acid-modified elastomer to 100 parts by weight of said styrene elastomer is 20 to 80 parts by weight. 5. The adhesive composition according to any one of claims 1 to 4, wherein a ratio of said epoxy resin curing agent to 50 parts by weight of said acid-modified elastomer is 0.01 to 1.5 parts by weight. thing. A laminate film having a cured layer formed by curing the adhesive composition according to any one of claims 1 to 5 on a base film. A printed wiring board comprising the laminated film according to claim 6 .