JP2001081282A - Epoxy resin composition and flexible printed wiring board material containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin composition that can give a flexible printed wiring board excellent in resistance to repeated flex, heat resistance, humidity resistance, and adhesion by mixing an epoxy resin with a curing agent and a phenolic-hydroxyl-containing polyamide/polybutadiene/acrylonitrile copolymer in a specified weight ratio. SOLUTION: This composition comprises (A) an epoxy resin, (B) a curing agent, and (C) a phenolic-hydroxyl-containing polyamide/polybutadiene/ acrylonitrile copolymer in a weight ratio C/(A+B+C) of 0.05-0.90. It is desirable that component C is the one obtained by reacting a dicarboxylic acid component containing a phenolic-hydroxyl-containing dicarboxylic acid with 3,4'- diaminodiphenyl ether, particularly, a copolymer represented by the formula. In the formula, x=3-7; y=1-4; z=5-15; 1+m=2-200; and m/(l+m)>=0.14. It is desirable that component A is a glycidyl ether type epoxy resin and that component B is a phenolic curing agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a flexible printed wiring board material, a flexible printed wiring board, a coverlay material and a bonding sheet, which have excellent repetitive bending resistance, adhesiveness, heat resistance and moisture resistance. The present invention relates to an epoxy resin composition having the same, a substrate for flexible printed wiring, a coverlay material, and a bonding sheet using the same.

[0002]

2. Description of the Related Art In recent years, the development of the electronics field has been remarkable, and in particular, the miniaturization of communication and consumer electronic devices,
With the progress of weight reduction and high density, demands for these performances are becoming more and more advanced. In response to such demands, flexible printed wiring boards are flexible and have the property of withstanding repeated bending, so that they can be mounted three-dimensionally and with high density in a narrow space, and can be connected to electronic devices. Its use is expanding as a composite component having a cable or a connector function. This flexible printed wiring board is obtained by forming a circuit on a substrate for flexible printed wiring by a conventional method, and depending on the purpose of use, the circuit is covered with a coverlay to protect it.

A flexible printed wiring board is formed by laminating and integrating an electrically insulating base film having high heat resistance and excellent electrical and mechanical properties with a metal foil via an adhesive. Characteristics required for the wiring substrate include adhesiveness, adhesion, heat resistance, electrical characteristics, workability, and the like.

In recent years, in particular, a COF (Chip on Chip) in which an IC chip is directly mounted on a flexible printed wiring board has been developed.
Flex) has been commercialized or CSP (ChipSca)
le Packaging, MCM (Multi C)
A flexible printed wiring board as a semiconductor package constituent material is required to further improve heat resistance and moisture resistance, for example, a flexible printed wiring board is adopted as an interposer of a hip module.

The coverlay is provided for protecting a circuit of a flexible printed wiring board, improving flexibility, and the like.
Types of coverlay materials include a film-based coverlay in which an adhesive is applied to one side of an electrically insulating base film, a dry film type in which the adhesive layer also serves as an insulating layer, a liquid type, and the like. The characteristics required for these coverlays are:
Examples include storability, adhesion, heat resistance, electrical characteristics, workability, and the like.

[0006] The bonding sheet is formed by laminating a release material having one surface coated with an adhesive and another release material. The bonding sheet is formed by laminating a flexible printed wiring board and a flexible printed wiring board to each other. Is used as an adhesive material for manufacturing flexible printed wiring boards and bonding reinforcing boards to flexible printed wiring boards. Properties required for this bonding sheet include storability, adhesion, heat resistance, electrical properties, workability, and the like.

Conventionally, nylon / epoxy resin, acrylic / phenol, and the like have been used as adhesives used in flexible printed wiring board materials such as flexible printed wiring boards, coverlay materials, bonding sheets, etc., which can satisfy these requirements. Adhesives of resin type, polyester / epoxy resin type, nitrile rubber (NBR) / epoxy resin type, etc. have been proposed, but the glass transition temperature is designed to be low in order to satisfy the repeated bending property, and the heat resistance and moisture resistance Was not satisfactory.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems by providing an epoxy resin composition having excellent flexibility and heat resistance and moisture resistance at the same time, and flexible printing using the same. Provided are a wiring substrate, a coverlay material, and a bonding sheet.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, by including a specific copolymer in a specific ratio, an epoxy resin which simultaneously satisfies the above-mentioned properties. It has been found that a resin composition can be obtained. That is, the present invention comprises (1) an epoxy resin (a), a curing agent (b), and a phenolic hydroxyl group-containing polyamide-polybutadiene-acrylonitrile copolymer (c), and their compounding weight ratio (weight ratio) is as follows. (C) / {(a) + (b) + (c)} = 0.05-0.
90, an epoxy resin composition,
(2) The compounding weight ratio is (c) / ｛(a) + (b) +
(C) The epoxy resin composition according to the above (1), wherein｝ = 0.30 to 0.70, (3) the phenolic hydroxyl group-containing polyamide-polybutadiene-acrylonitrile copolymer (c) has a phenolic hydroxyl group. The above-mentioned (1), which is obtained by reacting a dicarboxylic acid containing a dicarboxylic acid with a diamine and obtained by using 3,4′-diaminodiphenyl ether as the diamine.
Or the epoxy resin composition according to (2), and (4) a phenolic hydroxyl group-containing polyamide-polybutadiene-acrylonitrile copolymer (c) represented by the following formula (Formula 2)

[0010]

Embedded image

(Where x, y, z, l, m and n are average degrees of polymerization, respectively; x = 3-7, y = 1-4,
z is an integer of 5 to 15 and l + m is an integer of 2 to 200, and m / (l + m) ≧ 0.04. The epoxy resin composition according to any one of the above (1) to (3), wherein the epoxy resin (a) is a glycidyl ether type epoxy resin. The epoxy resin composition according to any one of (1) to (4),
(6) The epoxy resin composition according to the above (5), wherein the glycidyl ether type epoxy resin is a bisphenol A type epoxy resin, and (7) the above (5), wherein the glycidyl ether type epoxy resin is a bisphenol F type epoxy resin.
(8) The epoxy resin composition according to (5), wherein the glycidyl ether type epoxy resin is a phenol novolak type epoxy resin.
(9) The epoxy resin composition according to the above (8), wherein the phenol novolak type epoxy resin is a novolak type epoxy resin having a methyl group in a phenol skeleton.
0) The epoxy resin composition according to the above (5), wherein the glycidyl ether type epoxy resin is a novolak type epoxy resin having a phenol skeleton and a naphthol skeleton.
1) The epoxy resin composition according to the above (10), wherein the novolak type epoxy resin having a phenol skeleton and a naphthol skeleton is a novolak type epoxy resin having a methyl group in the phenol skeleton, and (12) the glycidyl ether type epoxy resin is phenol. The epoxy resin composition according to the above (5), which is a novolak type epoxy resin having a skeleton and a biphenyl skeleton; and (13) the epoxy resin composition according to the above (5), wherein the glycidyl ether type epoxy resin is a novolak type epoxy resin having a trifphenylmethane skeleton. (14) The epoxy resin composition according to (5), wherein the glycidyl ether type epoxy resin is a novolak type epoxy resin having a dicyclopentadiene skeleton, and (15) the curing agent (b) is phenol. (1) to () 4) The epoxy resin composition according to any one of the above items (1) to (15), wherein the glass transition point after curing is 80 ° C. or higher. (17) The epoxy resin composition according to the above (16), wherein the glass transition point after curing is 120 ° C. or more, (18) the epoxy resin composition according to any one of the above (1) to (17). (19) A coverlay film using the epoxy resin composition according to any one of the above (1) to (17), (20) a coverlay film using the epoxy resin composition according to any one of the above (1) to (17). And (21) a cured sheet obtained by curing the epoxy resin composition according to any one of (1) to (17). .

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The epoxy resin composition used in the present invention contains an epoxy resin (a), a curing agent (b), and a phenolic hydroxyl group-containing polyamide-polybutadiene-acrylonitrile copolymer (c).

Epoxy resin (a) used in the present invention
Are, for example, a polyfunctional epoxy resin which is a glycidyl etherified product of a polyphenol compound, a polyfunctional epoxy resin which is a glycidyl etherified product of various novolak resins, an alicyclic epoxy resin, a heterocyclic epoxy resin, a glycidyl ester-based epoxy resin, and glycidylamine. Examples include, but are not limited to, epoxy resins and epoxy resins obtained by glycidylation of halogenated phenols. Here, the polyfunctional epoxy resin is an epoxy resin having two or more glycidyl groups.

Examples of the polyfunctional epoxy resin which is a glycidyl etherified product of a polyphenol compound include bisphenol A, bisphenol F, bisphenol S, 4,4′-biphenylphenol, tetramethylbisphenol A, dimethylbisphenol A, and tetramethylbisphenol F , Dimethylbisphenol F, tetramethylbisphenol S, dimethylbisphenol S, tetramethyl-4,4'-biphenol, dimethyl-4,4'-biphenylphenol, 1- (4-hydroxyphenyl) -2- [4- (1 , 1-bis- (4-hydroxyphenyl) ethyl) phenyl] propane, 2,
2′-methylene-bis (4-methyl-6-tert-butylphenol), 4,4′-butylidene-bis (3-
Methyl-6-tert-butylphenol), trishydroxyphenylmethane, resorcinol, hydroquinone, pyrogallol, phenols having a diisopropylidene skeleton, phenols having a fluorene skeleton such as 1,1-di-4-hydroxyphenylfluorene, phenol And polyfunctional epoxy resins which are glycidyl etherified products of polyphenol compounds such as polybutadiene.

Examples of polyfunctional epoxy resins which are glycidyl etherified compounds of various novolak resins include various phenols such as phenol, cresols, ethylphenols, butylphenols, octylphenols, bisphenol A, bisphenol F, bisphenol S, naphthols and the like. Glycidyl of various novolak resins such as novolak resin, phenol novolak resin containing xylylene skeleton, phenol novolak resin containing dicyclopentadiene skeleton, phenol novolak resin containing biphenyl skeleton, phenol novolak resin containing fluorene skeleton, and phenol novolak resin containing furan skeleton Etherified compounds.

Examples of the alicyclic epoxy resin include an alicyclic epoxy resin having an aliphatic skeleton such as cyclohexane, and examples of the aliphatic epoxy resin include 1,4-butanediol and 1,6-hexane. Diol,
Glycidyl ethers of polyhydric alcohols such as polyethylene glycol and pentaerythritol are mentioned.

Examples of the heterocyclic epoxy resin include a heterocyclic epoxy resin having a heterocyclic ring such as an isocyanuric ring and a hydantoin ring, and examples of the glycidyl ester-based epoxy resin include diglycidyl hexahydrophthalate and the like. Examples of the epoxy resin include carboxylic acids. Examples of the glycidylamine-based epoxy resin include epoxy resins obtained by glycidylation of amines such as aniline and toluidine.

Examples of epoxy resins obtained by glycidylation of halogenated phenols include brominated bisphenol A, brominated bisphenol F, brominated bisphenol S, brominated phenol novolak, brominated cresol novolak, chlorinated bisphenol S, and chlorinated bisphenol. An epoxy resin obtained by glycidylation of a halogenated phenol such as A is exemplified.

[0020] Among these epoxy resins, which epoxy resin is used is appropriately selected depending on required characteristics, but a glycidyl ether type epoxy resin is preferable, and a bisphenol A type epoxy resin and a bisphenol F type epoxy resin are more preferable. Phenol novolak epoxy resin, cresol novolak epoxy resin, novolak epoxy resin having phenol skeleton and naphthol skeleton, novolak epoxy resin having phenol skeleton and biphenyl skeleton, novolak epoxy resin having triphenylmethane skeleton, dicyclo It is a novolak type epoxy resin having a pentadiene skeleton. The novolak type epoxy resin having a phenol skeleton and a naphthol skeleton is more preferably a resin having a methyl group in the phenol skeleton. For example, NC-7000 (trade name: manufactured by Nippon Kayaku Co., Ltd.) and NC-7300 (trade name:
Nippon Kayaku Co., Ltd.). A novolak-type epoxy resin having a phenol skeleton and a biphenyl skeleton is commercially available, for example, as NC-3000P (trade name, manufactured by Nippon Kayaku Co., Ltd.). Novolak-type epoxy resins having a triphenylmethane skeleton include, for example, E
It is commercially available as PPN-501H and EPPN-502H (trade name: manufactured by Nippon Kayaku Co., Ltd.). A novolak type epoxy resin having a dicyclopentadiene skeleton is commercially available as, for example, XD-1000 (trade name: manufactured by Nippon Kayaku Co., Ltd.). Further, these epoxy resins can be used as one kind or as a mixture of two or more kinds as required, for example, for imparting heat resistance and flame retardancy.

The curing agent (b) used in the present invention includes, for example, acid anhydrides, amines, phenols, imidazoles, dihydrazines, Lewis acids, Bronsted acid salts, polymercaptons, isocyanates, And block isocyanates.

Examples of the acid anhydride that can be used include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, ethylene glycol trimellitic anhydride, and biphenyltetracarboxylic anhydride. Carboxylic acid anhydrides such as anhydrides, azelaic acid, sebacic acid, aliphatic carboxylic acid anhydrides such as dodecanedioic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, nadic anhydride, and heptonic anhydride And alicyclic carboxylic acid anhydrides such as hymic acid anhydride.

Examples of amines that can be used include diaminodiphenylmethane, diaminodiphenylsulfone, diaminodiphenylether, p-phenylenediamine, m-phenylenediamine, o-phenylenediamine, 1,5-diaminonaphthalene, and m-xylylenediamine. Aromatic amine, ethylenediamine, diethylenediamine, isophoronediamine, bis (4-amino-
Aliphatic amines such as 3-methyldicyclohexyl) methane and polyetherdiamine, dicyandiamide, 1- (o
-Tolyl) guanidines such as biguanide;

Examples of usable phenols include bisphenol A, bisphenol F, bisphenol S, 4,4′-biphenylphenol, tetramethylbisphenol A, dimethylbisphenol A, tetramethylbisphenol F, dimethylbisphenol F, and tetramethylbisphenol S , Dimethylbisphenol S, tetramethyl-4,4'-biphenol, dimethyl-4,4'-biphenylphenol, 1- (4-hydroxyphenyl) -2- [4- (1,1-bis- (4-hydroxy Phenyl) ethyl) phenyl] propane, 2,
2′-methylene-bis (4-methyl-6-tert-butylphenol), 4,4′-butylidene-bis (3-
Methyl-6-tert-butylphenol), trishydroxyphenylmethane, resorcinol, hydroquinone, pyrogallol, phenols having a diisopropylidene skeleton, phenols having a fluorene skeleton such as 1,1-di-4-hydroxyphenylfluorene, phenol Resins derived from various phenols such as polybutadiene, phenol, cresols, ethylphenols, butylphenols, octylphenols, bisphenol A, bisphenol F, bisphenol S, and naphthols, phenol novolak resins containing a xylylene skeleton, dicyclopentadiene Phenol novolak resin containing skeleton, phenol novolak resin containing biphenyl skeleton, phenol novolak resin containing fluorene skeleton, fura Various novolak resins such as skeleton-containing phenol novolak resins, brominated bisphenol A, brominated bisphenol F, brominated bisphenol S, brominated phenol novolak, brominated cresol novolac, chlorinated bisphenol S, halogenated phenols such as chlorinated bisphenol A And the like.

Examples of usable imidazoles include 2-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenyl-4-methylimidazole,
1-benzyl-2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-
Methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 2,4-diamino-6 (2′-methylimidazole (1 ′)) ethyl-s-triazine, 2,4- Diamino-6 (2'-undecylimidazole (1 '))
Ethyl-s-triazine, 2,4-diamino-6 (2 ′
-Ethyl, 4-methylimidazole (1 ')) ethyl-
s-Triazine, 2,4-diamino-6 (2′-methylimidazole (1 ′)) ethyl-s-triazine.isocyanuric acid adduct, 2-methylimidazole 2: 3 adduct of isocyanuric acid, 2-phenylimidazole Isocyanuric acid adduct, 2-phenyl-3,5-dihydroxymethylimidazole, 2-phenyl-4-hydroxymethyl-5-methylimidazole, 1-cyanoethyl-2
Various imidazoles of -phenyl-3,5-dicyanoethoxymethylimidazole, and those imidazoles and phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, naphthalenedicarboxylic acid, maleic acid, oxalic acid, etc. And salts with polyvalent carboxylic acids.

[0026] Among these curing agents, which curing agent is used is appropriately selected according to the characteristics required for the adhesive, and is preferably a phenol.

The amount of the curing agent (b) used is generally in the range of 0.3 to 2.0, preferably 0.4 to 2.0, in terms of the equivalent ratio of the curing agent to the epoxy group of the epoxy resin (a).
It is used in the range of 1.6, more preferably in the range of 0.5 to 1.3. The above curing agents can be used as a mixture of two or more kinds.

The Tg (glass transition point) after curing of the epoxy resin composition of the present invention is preferably 80 ° C. or more, more preferably 120 ° C. or more, from the viewpoint of heat resistance, moisture resistance and pressure cooker resistance. is there. T in this case
g is the temperature of the maximum value of tan δ when the epoxy resin composition molded and cured into a film is measured by a dynamic viscoelasticity method (DMA method).

In the present invention, a phenolic hydroxyl group-containing polyamide-polybutadiene-acrylonitrile copolymer (c) is used. This is necessary for imparting bending resistance and adhesiveness, and by adding the same, flexibility can be imparted to the cured product, and at the same time, the adhesive strength with other flexible substrate constituting materials can be increased. In the entire epoxy resin composition, the weight ratio of the phenolic hydroxyl group-containing polyamide-polybutadiene-acrylonitrile copolymer (c) to the epoxy resin (a) and the curing agent (b) was (c) / ｛(a ) + (B) + (c)｝ = 0.05-0.
90, more preferably (c) /
{(A) + (b) + (c)} = 0.30 to 0.70.

The phenolic hydroxyl group-containing polyamide-polybutadiene-acrylonitrile copolymer (c) used in the present invention can be synthesized, for example, by the following method. That is, an excess amount of diamine is added to a dicarboxylic acid component containing a dicarboxylic acid having a phenolic hydroxyl group,
These are heated and stirred, for example, in an organic solvent represented by N-methyl-2-pyrrolidone under an inert atmosphere such as nitrogen, using a condensing agent in the presence of a phosphite and a pyridine derivative. The reaction is performed to produce a polyamide oligomer containing a phenolic hydroxyl group. As a result, it can be obtained by adding a polybutadiene-acrylonitrile copolymer having a carboxyl group at both ends to the obtained phenolic hydroxyl group-containing polyamide oligomer solution having amino groups at both ends and subjecting the solution to polycondensation. Further, the dicarboxylic acid was added to the diamine in excess to synthesize the polyamide in which both ends became a carboxylic acid group, and the both ends were blocked using a polybutadiene-acrylonitrile copolymer having amino groups at both ends. It can also be converted. Furthermore, it is also possible to modify the terminal of these polyamide or polybutadiene-acrylonitrile copolymers into functional groups that can be blocked.
Other combinations of functional groups include vinyl groups and -N
Examples thereof include a combination with an H group or an -SH group. In order to contain a phenolic hydroxyl group in the polyamide portion of the block copolymer synthesized in this manner, a dicarboxylic acid containing a phenolic hydroxyl group or a diamine containing a phenolic hydroxyl group is contained in the dicarboxylic acid or diamine. This is possible by conducting the above-mentioned condensation polymerization.

The phenolic hydroxyl group-containing dicarboxylic acid used in the phenolic hydroxyl group-containing polyamide-polybutadiene-acrylonitrile copolymer (c) includes, for example, 5-hydroxyisophthalic acid, 4-hydroxyisophthalic acid, 2-hydroxyphthalic acid, 3-hydroxyphthalic acid, 2-hydroxyterephthalic acid, dicarboxylic acids having no phenolic hydroxyl group include phthalic acid, isophthalic acid, terephthalic acid, dicarboxylnaphthalene, succinic acid, fumaric acid, glutaric acid, adipic acid, 3-cyclohexanedicarboxylic acid, 4,4'-
Examples include diphenyldicarboxylic acid and 3,3'-methylene dibenzoic acid.

As the diamine component, as a diamine containing a phenolic hydroxyl group, 3,3′-diamine-
4,4'-dihydroxyphenylmethane, 2,2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane, 2,2-bis (3-amino-4-hydroxyphenyl) difluoromethane, 3,4-diamino -1,5
-Benzenediol, 3,3'-dihydroxy-4,
4'-diaminobisphenyl, 3,3'-diamino-
4,4'-dihydroxybiphenyl, 2,2-bis (3
-Amino-4-hydroxyphenyl) ketone, 2,2-
Bis (3-amino-4-hydroxyphenyl) sulfide, 2,2-bis (3-amino-4-hydroxyphenyl) ether, 2,2-bis (3-amino-4-hydroxyphenyl) sulfone, 2,2 -Bis (3-amino-
4-hydroxyphenyl) propane, 2,2-bis (3
-Hydroxy-4-aminophenyl) propane, 2,2
As a diamine containing no phenolic hydroxyl group, such as -bis (3-hydroxy-4-aminophenyl) methane,
3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, diaminonaphthalene, piperazine, hexanetylenediamine, tetramethylenediamine, m-xylenediamine, 4,4'-diaminodiphenylmethane , 4,4'-diaminobenzophenone, 2,2'-bis (4-aminophenyl) propane, 3,3'-diaminodiphenylsulfone, 3,3'-diaminodiphenyl and the like. Diaminodiphenyl ether is preferable, but the present invention is not limited to these.

Of these, a particularly preferred phenolic hydroxyl group-containing polyamide-polybutadiene-acrylonitrile copolymer (c) is represented by the following formula (Formula 3)

[0034]

Embedded image

(Where x, y, z, l, m and n are average degrees of polymerization, respectively; x = 3-7, y = 1-4,
z is an integer of 5 to 15 and l + m is an integer of 2 to 200, and m / (l + m) ≧ 0.04. ).

A polybutadiene-acrylonitrile copolymer having various functional groups at both terminals is available from Goodr.
It is commercially available as Hycar CTBN from ich and can be used to block them with the phenolic hydroxyl-containing polyamides described above.

The epoxy resin composition of the present invention may contain a curing accelerator, if necessary. Examples of the curing accelerator include phosphorus compounds such as triphenylphosphine, for example, triethylamine, tetraethanolamine, 1,8-diaza-bicyclo [5.4.
0] -7-undecene (DBU), tertiary amines such as N, N-dimethylbenzylamine, 1,1,3,3-tetramethylguanidine, 2-ethyl-4-methylimidazole, N-methylpiperazine Compounds, for example 1,8-
And boron-based compounds such as diaza-bicyclo [5.4.0] -7-undecenium tetraphenylborate.

[0038] Other additives can be added to the epoxy resin composition of the present invention as needed. For example, plasticizers such as natural waxes, synthetic waxes and metal salts of long-chain aliphatic acids, release agents such as acid amides, esters and paraffins, stress relievers such as nitrile rubber and butadiene rubber, and trioxide Inorganic flame retardants such as antimony, antimony pentoxide, tin oxide, tin hydroxide, molybdenum oxide, zinc borate, barium metaborate, red phosphorus, aluminum hydroxide, magnesium hydroxide, calcium aluminate, tetrabromobisphenol A, tetrabromo anhydride Brominated flame retardants such as phthalic acid, hexabromobenzene, brominated phenol novolak, coupling agents such as silane coupling agents, titanate coupling agents, aluminum coupling agents, fused silica, crystalline silica, low α Linear silica, glass flake, glass beads, glass balloon, talc Metals such as alumina, calcium silicate, aluminum hydroxide, calcium carbonate, barium sulfate, magnesia, silicon nitride, boron nitride, ferrite, rare earth cobalt, gold, silver, nickel, copper, lead, iron powder, iron oxide, iron sand, etc. Inorganic fillers such as powder, graphite, carbon, red iron oxide, and graphite or conductive particles, coloring agents such as dyes and pigments, carbon fiber, glass fiber, boron fiber, silicon carbide fiber, alumina fiber, silica-alumina fiber Such as inorganic fibers, organic fibers such as aramid fibers, polyester fibers, cellulose fibers, and carbon fibers, oxidation stabilizers, light stabilizers, moisture resistance improvers, thixotropy-imparting agents, diluents, defoamers, and various other types. , A resin, a tackifier, an antistatic agent, a lubricant, an ultraviolet absorber, and the like.

The epoxy resin composition of the present invention comprises an epoxy resin (a), a curing agent (b), a phenolic hydroxyl group-containing polyamide-polybutadiene-acrylonitrile copolymer (c), a curing accelerator if necessary, and other additives. When used as an adhesive described below, a varnish is obtained by uniformly mixing the above components at a predetermined ratio in a solvent. Examples of the solvent in this case include organic solvents such as toluene, ethanol, cellosolve, tetrahydrofuran, N-methyl-2-pyrrolidone, and dimethylformamide.

The curing of the epoxy resin composition of the present invention comprises:
It is mainly carried out by heat curing, but it is also possible to use, for example, room temperature curing caused by a catalyst or oxygen or moisture at around room temperature, or photocuring caused by a catalyst caused by an acid generated by ultraviolet irradiation.

The epoxy resin composition of the present invention can be preferably used as an adhesive constituting a flexible printed wiring board, a cover lay material, and a bonding sheet (hereinafter, collectively referred to as a flexible printed wiring board material). The configuration of the flexible wiring substrate has a three-layer structure of an electrically insulating film / adhesive / metal foil, and the thickness of the adhesive is generally 10 to 20 μm, but is appropriately determined depending on the use conditions and the like. As a form of the coverlay material, a film base coverlay in which an adhesive is applied to one side of a base film is mainly used. The structure of the film base coverlay is a three-layer structure composed of an electrically insulating film / adhesive / release material, and the thickness of the adhesive is generally 15 to 50 μm.
However, it is determined as appropriate depending on the use situation and the like. In addition,
The form of the coverlay includes a dry film type, a liquid type and the like. The dry film type has a three-layer structure including a release material / adhesive / release material, and the adhesive layer also serves as an insulating layer. The thickness of the adhesive is generally 25 to 100 μm, but can be appropriately determined depending on the use conditions and the like. The liquid type forms an insulating layer by coating and curing. The configuration of the bonding sheet is a three-layer structure composed of a release material / a thermosetting adhesive / a release material, and the thickness of the adhesive is generally 15 to 50 μm, but is appropriately determined depending on the use conditions and the like.

Examples of the electrically insulating film that can be used in the present invention include a polyimide film, a PET (polyethylene terephthalate) film, a polyester film, a polyparabanic acid film, a polyetheretherketone film, a polyphenylene sulfide film, and an aramid film. Among them, a polyimide film is preferred from the viewpoint of heat resistance, dimensional stability, mechanical properties and the like. The thickness of the film is usually in the range of 12.5 to 75 μm, but an appropriate thickness may be used as needed.
One or both surfaces of these films may be subjected to a surface treatment such as a low-temperature plasma treatment, a corona discharge treatment, and a sandblast treatment.

The metal foil usable in the present invention includes an electrolytic copper foil, a rolled copper foil, an aluminum foil, a tungsten foil,
An iron foil or the like is exemplified, and generally, an electrolytic copper foil or a rolled copper foil is used in view of workability, flexibility, electric conductivity, and the like. The thickness of the metal foil is generally from 18 to 70 μm, but can be appropriately determined depending on the use conditions and the like.

The release material usable in the present invention includes polyethylene film, polypropylene film, TPX
Film, PE film, polyethylene film with silicone release agent, polypropylene film and PE film, polyethylene resin coated paper, polypropylene resin coated paper and TPX resin coated paper, etc., and the thickness of the release material is based on film. The thickness is preferably from 13 to 75 μm, and from 50 to 200 μm for a paper base, but an appropriate thickness may be used as necessary.

Hereinafter, a method for producing the above-mentioned flexible printed wiring board material will be described. In the method for producing a substrate for flexible printed wiring of the present invention, a varnish (adhesive) made of the epoxy resin composition of the present invention prepared in advance is applied to the electrical insulating film using a roll coater, a comma coater or the like. . This is passed through an in-line dryer and heat-treated at 40 to 160 ° C. for 2 to 20 minutes to remove the solvent in the adhesive to form an adhesive layer. The adhesive-coated surface of the release material with adhesive and the release material are pressed by a heating roll. The coating thickness of the adhesive is generally 10 to 10 in a dry state.
What is necessary is just 20 micrometers.

In the method for producing a film-based coverlay of the present invention, a varnish (adhesive) made of the epoxy resin composition of the present invention prepared in advance is applied to the electric insulating film using a roll coater, a comma coater or the like. I do.
This is passed through an in-line dryer and heat-treated at 40 to 160 ° C. for 2 to 20 minutes to remove the solvent in the adhesive to form an adhesive layer. The adhesive-coated surface of the film with the adhesive and the release material are pressed by a heating roll. The thickness of the applied adhesive may be generally 15 to 50 μm in a dry state.

In the method for producing a dry film type coverlay of the present invention, a varnish (adhesive) made of the epoxy resin composition of the present invention prepared in advance is applied to a release material using a roll coater, a comma coater or the like. I do. Pass this through an in-line dryer at 40-160 ° C for 2-
Heat treatment is performed for 20 minutes to remove the solvent in the adhesive to form an adhesive layer. The adhesive-coated surface of the release material with adhesive and the release material are pressed by a heating roll. The thickness of the adhesive applied may be generally 25 to 100 μm in a dry state.

The method for producing a liquid type coverlay of the present invention is obtained by adjusting a varnish (adhesive) made of the epoxy resin composition of the present invention prepared in advance to a viscosity suitable for a coating method.

In the method for producing a bonding sheet of the present invention, a varnish (adhesive) made of the epoxy resin composition of the present invention prepared in advance is applied to a release material using a roll coater, a comma coater or the like. This is passed through an in-line dryer and heat-treated at 40 to 160 ° C. for 2 to 20 minutes to remove the solvent in the adhesive to form an adhesive layer. The adhesive-coated surface of the release material with adhesive and the release material are pressed by a heating roll. The thickness of the applied adhesive may be generally 15 to 50 μm in a dry state.

[0050]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited thereto. In Examples and Comparative Examples,% and parts are by weight unless otherwise specified. The unit of epoxy equivalent and hydroxyl equivalent is g / eq.

Synthesis Example 1 Synthesis of polyamide A (phenolic hydroxyl group-containing aromatic polyamide-polybutadiene / acrylonitrile block copolymer). 19.93 g (120 mmol) of isophthalic acid, 3,4'-diaminodiphenyl ether 30.6
3 g (153 mmol), 3.64 g (20 mmol) of 5-hydroxyisophthalic acid, 3.9 g of lithium chloride,
12.1 g of calcium chloride, 240 ml of N-methyl-2-pyrrolidone and 54 ml of pyridine were placed in a 1-liter four-necked round-bottomed flask, stirred and dissolved, and 74 g of triphenyl phosphite was added thereto. For 4 hours to produce a phenolic hydroxyl group-containing aromatic polyamide oligomer. In addition, a polybutadiene / acrylonitrile copolymer having carboxyl groups at both ends (Hyc
ar CTBN, manufactured by BF Goodrich. The acrylonitrile component contained in the polybutadiene acrylonitrile part is 17 mol% and has a molecular weight of about 3600).
A solution dissolved in 40 ml of N-methyl-2-pyrrolidone was added, and the reaction was further carried out for 4 hours. After cooling to room temperature, the reaction solution was poured into 20 liters of methanol, and the polybutadiene / acrylonitrile copolymer used in the present invention was used. The content of the coalesced part is 50 wt%, and the phenolic hydroxyl group is reduced to about 14%.
An aromatic polyamide-polybutadiene / acrylonitrile block copolymer containing mol% was precipitated. The precipitated polymer was further purified by washing with methanol and refluxing methanol. The intrinsic viscosity of this polymer is 0.85 dl /
g (dimethylacetamide, 30 ° C.). When an infrared spectrum of the polymer powder was measured by a diffuse reflection method, an amide carbonyl group was found at 1,674 cm ^-1 .
The absorption based on C-H bonds of the butadiene part in 6-2975cm ^-1, revealed absorption based on nitrile group in 2245 cm ^-1.

Example 1 (Example of a substrate for flexible printed wiring) The composition (weight ratio) shown in the column of Example 1 in (Table 1) was used as an epoxy resin composition, and 1 weight of N-methyl-2-pyrrolidone (NMP) was used. The resin was dissolved in a mixed solvent of 1 part by weight of MEK (methyl ethyl ketone) to prepare a 50% by weight resin solution. The compounding amount of the curing agent was 1.0 in equivalent ratio. Next, the above resin solution was applied on a 25 μm-thick Kapton film (trade name, manufactured by Du Pont-Toray Co., Ltd., polyimide film) using a roll coater so that the thickness after drying was 18 μm, and 120 ° C. The solvent was removed under a drying condition of 10 minutes. The adhesive layer did not crack, chip, or peel off even when the Kapton film was curved, and had sufficient strength and flexibility. The treated surface of 35 μm-thick BHN foil (trade name; rolled copper foil manufactured by Japan Energy Co., Ltd.)
Crimping was performed at 100 ° C. under a linear pressure of 2 kg / cm. This was subjected to a heat treatment at 160 ° C. for 2 hours, and the adhesive was cured to obtain a flexible printed wiring board. The thus obtained flexible printed wiring board was used as a sample for evaluation, and its physical properties were evaluated. The results are shown in Table 2. (Example of film base coverlay) The composition shown in the column of Example 1 in Table 1 as an epoxy resin composition was added to MEK1 based on 1 part by weight of N-methyl-2-pyrrolidone (NMP).
It was dissolved in parts by weight of a mixed solvent to prepare a 50% by weight resin solution. The compounding amount of the curing agent was 1.0 in equivalent ratio. Next, the resin solution was applied on a 25 μm-thick Kapton film (trade name, manufactured by Du Pont-Toray Co., Ltd., polyimide film) using a roll coater so that the thickness after drying was 35 μm. The solvent was removed under drying conditions for 10 minutes. The adhesive layer did not crack, chip, or peel off even when the Kapton film was curved, and had sufficient strength and flexibility. A polyethylene-coated paper treated with a silicone resin was thermocompression-bonded to the adhesive surface of the Kapton film with the adhesive layer to obtain a film base coverlay. A sample for evaluation was prepared for the film base coverlay thus obtained, and its physical properties were evaluated. The results are shown in Table 3. (Example of Dry Film Coverlay) The composition shown in the column of Example 1 in Table 1 as an epoxy resin composition was added to MEK1 with respect to 1 part by weight of N-methyl-2-pyrrolidone (NMP).
It was dissolved in parts by weight of a mixed solvent to prepare a 50% by weight resin solution. The compounding amount of the curing agent was 1.0 in equivalent ratio. Next, the adhesive solution was applied on a silicone-treated PET film (thickness: 25 μm) by a roll coater so that the thickness after drying was 75 μm, and the solvent was dried at 100 ° C. for 10 minutes. Was removed to leave the adhesive in a semi-cured state. A dry film coverlay was obtained by thermocompression-bonding a silicone-coated polyethylene-coated paper (thickness: 130 μm) to the adhesive surface of the PET film with adhesive in the semi-cured state. A sample for evaluation was prepared for the dry film coverlay thus obtained, and its physical properties were evaluated. The results are shown in Table 4 below. (Example of liquid coverlay) The composition shown in the column of Example 1 of (Table 1) as the epoxy resin composition was changed to N-methyl-2-.
It was dissolved in a mixed solvent of 1 part by weight of MEK with respect to 1 part by weight of pyrrolidone (NMP) to prepare a resin solution of 50% by weight.
The compounding amount of the curing agent was 1.0 in equivalent ratio. A sample for evaluation was prepared for the liquid coverlay thus obtained, and its physical properties were evaluated. The results are shown in (Table 5). (Example of bonding sheet) The composition shown in the column of Example 1 of (Table 1) was N-methyl-2 as the epoxy resin composition.
The resin was dissolved in a mixed solvent of 1 part by weight of MEK with respect to 1 part by weight of pyrrolidone (NMP) to prepare a 50% by weight resin solution. The compounding amount of the curing agent was 1.0 in equivalent ratio. Next, the adhesive solution was applied on a silicone-treated PET film (thickness: 25 μm) using a roll coater so that the thickness after drying became 50 μm, and the solvent was dried at 100 ° C. for 10 minutes. Was removed to leave the adhesive in a semi-cured state. A polyethylene-coated paper (thickness: 130 μm) treated with a silicone resin was thermocompression-bonded to the adhesive surface of the semi-cured PET film with an adhesive to obtain a bonding sheet. A sample for evaluation was prepared for the bonding sheet thus obtained, and its physical properties were evaluated. The results are shown in (Table 6).

Examples 2 to 10 and Comparative Examples 1 and 2 (Examples of Flexible Printed Wiring Board) Examples 2 to 10 and Comparative Examples 1 and 2 of (Table 1) as epoxy resin compositions
In the same manner as in Example 1 except that the compositions shown in the respective columns were used, a flexible printed wiring board was prepared. The evaluation results of the physical properties of the substrate for flexible printed wiring are shown in (Table 2). (Example of film base coverlay) A film base cover was prepared in the same manner as in Example 1 except that the compositions shown in Examples 2 to 10 of Table 1 and Comparative Examples 1 and 2 were used as the epoxy resin composition. Created a ray. The evaluation results of the physical properties of the film-based coverlay are shown in (Table 3). (Example of Dry Film Coverlay) Dry film cover was performed in the same manner as in Example 1 except that the compositions shown in Examples 2 to 10 of Table 1 and Comparative Examples 1 and 2 were used as the epoxy resin composition. Created a ray. The results of evaluation of the physical properties of this dry film coverlay are shown in (Table 4). (Example of Liquid Coverlay) A liquid coverlay was prepared in the same manner as in Example 1 except that the compositions shown in Examples 2 to 10 of Table 1 and Comparative Examples 1 and 2 were used as the epoxy resin composition. Created. The evaluation results of the physical properties of this liquid coverlay are shown in (Table 5). (Example of bonding sheet) A bonding sheet was prepared in the same manner as in Example 1 except that the compositions shown in Examples 2 to 10 of Table 1 and Comparative Examples 1 and 2 were used as the epoxy resin composition. . The evaluation results of the physical properties of this bonding sheet are shown in (Table 6).

The methods for preparing evaluation samples and the methods for evaluating physical properties in Examples and Comparative Examples are as follows. Method for preparing evaluation samples (Sample for DMA measurement) On an aluminum plate coated with a mold release agent The resin solutions prepared in Examples and Comparative Examples were applied with an applicator so that the dry film thickness was about 80 μm. The solvent was removed under a drying condition of 120 ° C. for 10 minutes, and then cured at 160 ° C. for 2 hours. The cured coating film was peeled off from the aluminum plate and cut to a width of 5 mm.
A sample for MA measurement was used. (Flexible Printed Wiring Board) The flexible printed wiring boards produced in the examples and comparative examples were used as they were as samples for evaluation. The evaluation items were peel strength, solder heat resistance test, peel strength after long-term heating, and peel strength after pressure cooker test (PCT). (Flexible Printed Wiring Board for Coverlay Evaluation) Example 1
JIS C6 for flexible printed wiring board prepared in
A circuit having a width of 1 mm conforming to 471 was prepared by a standard method (screen printing → copper etching) and used as the following flexible printed wiring board for coverlay evaluation. (Film base cover lay) The release material of the film base cover lay was peeled off, and a flexible printed wiring board for cover lay evaluation was heat-pressed at 160 ° C. × 5 MPa for 30 minutes and used as a sample for evaluation. The evaluation items were a solder heat resistance test, an MIT bending resistance test, and a circuit embedding property. (Dry film cover lay) The release material of the dry film cover lay was peeled off on one side, and then heat-pressed with a flexible printed wiring board for cover lay evaluation at 160 ° C. × 5 MPa for 30 minutes. Finally, the release material on the opposite side was peeled off Was used as a sample for evaluation. The evaluation items were a solder heat resistance test, an MIT bending resistance test, and a circuit embedding property. (Liquid Coverlay) A liquid coverlay was applied to a flexible printed wiring board for coverlay evaluation using an applicator so as to have a dry film thickness of 40 μm, dried at 100 ° C. for 10 minutes, and then heated and cured at 160 ° C. for 30 minutes. These were used as evaluation samples. Evaluation items were solder heat test, M
IT bending resistance test, circuit embedding property. (Bonding Sheet) The release material on one side of the bonding sheet is peeled off, and the adhesive applied surface of the bonding sheet is temporarily fixed to the glossy surface of a 35 μm thick BHN foil (described above).
Next, the release material on the other side was peeled off, a 25 μm-thick Kapton film was placed on this adhesive-coated surface, and the composition was Kapton film / bonding sheet (product from which the release material had been removed) / the glossy surface of the BHN foil at 160 ° C. × 5 MPa. 30 under the condition
What was heated and pressed for one minute was used as a sample for evaluation.
The evaluation items were peel strength, solder heat resistance test, peel strength after long-term heating, and peel strength after pressure cooker test (PCT).

Method for evaluating physical properties of evaluation sample Tg (DMA method): The DMA measurement sample was subjected to a dynamic viscoelasticity measurement apparatus (manufactured by Seiko Instruments: DMS).
-100). Measurement temperature range is 20 to 300
° C, the measurement conditions were 2 ° C / min in temperature, the measurement frequency was 10 Hz,
The measurement was performed in the shear mode, and the maximum value of tan δ was defined as Tg. The measurement results are shown in (Table 1). Peeling strength: A sample for evaluation cut into a width of 10 mm was peeled off from the copper foil side at 50 mm / min in a 90 ° direction using a Tensilon tester (manufactured by Toyo Baldwin), and the strength was measured. Solder heat resistance test: Based on JIS C6471. 20
25 ° C., 60% RH for 24 hours
After being cut into a square of mm and floating on a solder bath at 350 ° C. for 30 seconds, the appearance was visually inspected. At this time, swelling,
The presence or absence of peeling was confirmed. ：: no swelling or peeling ×: swelling or peeling Peel strength after long-term heating: 15 samples for peel strength measurement
After the heat treatment at 0 ° C. × 240 hours, the peel strength was measured. Peel strength after pressure cooker test (PCT): A peel strength evaluation sample was treated at 121 ° C. and 2 atm for 20 hours, and then the peel strength was measured. MIT bending resistance test: Based on JIS P8115. A bending test was carried out on an MIT tester (manufactured by Yasuda Seiki Seisakusho) for a sample obtained by cutting the evaluation sample to a width of 10 mm. Tip bending radius 0.38mmR, load 0.5k
The bending test was performed under the condition of g, and the number of times of occurrence of cracks, floating, peeling and the like was recorded. The appearance was visually inspected. Circuit embedding property: The coverlay evaluation circuit was observed with a 40 × stereo microscope, and the embedding property of the copper circuit coverlay adhesive in the circuit was observed. ：: no embedding failure ×: embedding failure.

[0056]

[Table 1]

[0057]

[Table 2]

[0058]

[Table 3]

[0059]

[Table 4]

[0060]

[Table 5]

[0061]

[Table 6]

In Table 1, abbreviations indicate the following. Epoxy resin A: Epomic R-302 (bisphenol A type epoxy resin; manufactured by Mitsui Chemicals, Inc .; epoxy equivalent: 650) Epoxy resin B: Epototo YDF-2001 (bisphenol F type epoxy resin; manufactured by Toto Kasei Corporation; epoxy equivalent: 470) Epoxy resin C: EOCN-1020 (cresol novolak type epoxy resin; Nippon Kayaku Co., Ltd .; epoxy equivalent: 195) Epoxy resin D: NC-7000 (novolak type epoxy resin having a phenol skeleton and a naphthol skeleton; Nippon Kayaku Co., Ltd.) Epoxy resin E: NC-3000P (Novolak type epoxy resin having a phenol skeleton and a biphenyl skeleton; Nippon Kayaku Co., Ltd .; Epoxy equivalent: 285) Epoxy resin F: EPPN-502H (Triphe Novolak epoxy resin having a methane skeleton; Nippon Kayaku Co., Ltd .; Epoxy equivalent: 171) Epoxy resin G: XD-1000 (Novolak epoxy resin having a dicyclopentadiene skeleton; Nippon Kayaku Co., Ltd .; Epoxy equivalent: 254) Epoxy resin H: BREN-S (brominated phenol novolak type epoxy resin; Nippon Kayaku Co., Ltd .; epoxy equivalent: 280; Br content about 35%) Curing agent A: PN-80 (phenol novolak resin; Japan) Curing agent B: Kayahard NHN (novolak resin having a phenol skeleton and a naphthol skeleton; Nippon Kayaku Co., Ltd .; hydroxyl equivalent: 143) Curing agent C: Kayahard TPM (triphenylmethane) Novolac epoxy resin with skeleton; Nippon Kayaku Co., Ltd. Accelerator A: 2MZ-A (imidazole-based curing accelerator; manufactured by Shikoku Chemicals) Accelerator B: Triphenylphosphine NBR: Nipol 1072 (nitrile rubber; acrylonitrile content about 27%, carboxyl group-containing Rate 0.07
5%; manufactured by Zeon Corporation)

[0063]

The epoxy resin composition of the present invention retains excellent adhesive properties, solder heat resistance, etc., and has good physical properties even after long-term exposure to high temperature and high humidity conditions. The reliability of a flexible printed wiring board using the epoxy resin composition of (1) becomes extremely high.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 77:06) (72) Inventor Takumi 1325 Oji-gun, Sanyo-cho, Asa-gun, Yamaguchi Prefecture F-term (Reference) 4J002 AC073 AC112 AC113 CC032 CC082 CD011 CD021 CD041 CD051 CD061 CD071 CD111 CD121 CD131 CD171 CL073 EF126 EJ016 EJ036 EN036 EN076 EN096 ER026 EU116 EU186 EU196 FD142 FD146 FD150 GQ00 GQ01 5E314 AA08 GG01 FF08

Claims (21)

[Claims] An epoxy resin (a), a curing agent (b), and a phenolic hydroxyl group-containing polyamide-polybutadiene-acrylonitrile copolymer (c), and the compounding weight ratio (weight ratio) thereof is (c). / ｛(A) + (b) +
(C) An epoxy resin composition, wherein｝ = 0.05 to 0.90. 2. The compounding weight ratio is (c) / ｛(a) + (b) +
(C) The epoxy resin composition according to claim 1, wherein｝ = 0.30 to 0.70. 3. A phenolic hydroxyl group-containing polyamide-polybutadiene-acrylonitrile copolymer (c) obtained by reacting a dicarboxylic acid containing a dicarboxylic acid having a phenolic hydroxyl group with a diamine. 3. The epoxy resin composition according to claim 1, which is obtained using 4,4'-diaminodiphenyl ether. 4. A phenolic hydroxyl group-containing polyamide-polybutadiene-acrylonitrile copolymer (c) represented by the following formula (1): ## STR1 ## (Where x, y, z, l, m, and n are average polymerization degrees, respectively; x = 3-7, y = 1-4, z = 5-1)
5, l + m = integers of 2 to 200, and m /
(L + m) ≧ 0.04. The epoxy resin composition according to any one of claims 1 to 3, which is a copolymer represented by the following formula: 5. The epoxy resin composition according to claim 1, wherein the epoxy resin (a) is a glycidyl ether type epoxy resin. 6. The epoxy resin composition according to claim 5, wherein the glycidyl ether type epoxy resin is a bisphenol A type epoxy resin. 7. The epoxy resin composition according to claim 5, wherein the glycidyl ether type epoxy resin is a bisphenol F type epoxy resin. 8. The epoxy resin composition according to claim 5, wherein the glycidyl ether type epoxy resin is a phenol novolak type epoxy resin. 9. The epoxy resin composition according to claim 8, wherein the phenol novolak epoxy resin is a novolak epoxy resin having a methyl group in a phenol skeleton. 10. The epoxy resin composition according to claim 5, wherein the glycidyl ether type epoxy resin is a novolak type epoxy resin having a phenol skeleton and a naphthol skeleton. 11. The novolak epoxy resin having a phenol skeleton and a naphthol skeleton is a novolak epoxy resin having a methyl group in the phenol skeleton.
The epoxy resin composition according to 0. 12. The epoxy resin composition according to claim 5, wherein the glycidyl ether type epoxy resin is a novolak type epoxy resin having a phenol skeleton and a biphenyl skeleton. 13. The epoxy resin composition according to claim 5, wherein the glycidyl ether type epoxy resin is a novolak type epoxy resin having a triphenylmethane skeleton. 14. The epoxy resin composition according to claim 5, wherein the glycidyl ether type epoxy resin is a novolak type epoxy resin having a dicyclopentadiene skeleton. 15. The epoxy resin composition according to claim 1, wherein the curing agent (b) is a phenolic curing agent. 16. The epoxy resin composition according to claim 1, wherein the glass transition point after curing is 80 ° C. or higher. 17. The epoxy resin composition according to claim 16, wherein the glass transition point after curing is 120 ° C. or higher. 18. A flexible printed wiring board using the epoxy resin composition according to claim 1. Description: 19. A coverlay film using the epoxy resin composition according to any one of claims 1 to 17. 20. A bonding sheet using the epoxy resin composition according to any one of claims 1 to 17. 21. A cured product obtained by curing the epoxy resin composition according to any one of claims 1 to 17.