JPH04342720A - Epoxy resin composition for wiring substrate - Google Patents

Abstract

PURPOSE:To obtain the subject composition, containing an epoxy resin, a polyfunctional-phenolic compound, an imidazole compound and a specified copolymer and excellent in heat resistance, withstand voltage properties, mechanical characteristics and adhesion with hardly any occurrence of smear. CONSTITUTION:The objective composition containing (A) an epoxy resin, (B) a polyfunctional phenolic compound (blended in an amount of preferably 0.5-1.5 equiv. phenolic hydroxyl groups based on the epoxy resin), (C) an imidazole compound such as 2-ethylimidazole (blended in an amount of preferably 0.01-10wt.% based on the epoxy resin) and (D) preferably 1-15wt.% phenolic hydroxyl group-containing aramid-polybutadiene-acrylonitrile block copolymer expressed by the formula {x is 3-7; (y) is 1-4; [y/(x+y)] is 0.1-0.3; (z) is 5-15; (m) is 1-400; (n) is 1-400; [n/(n+m)] is 0.01-0.50; (1) is 1-50; Ar<1> and Ar<3> are containing bifunctional aromatic group}.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to an epoxy resin composition used for wiring boards, and in particular, it has excellent heat resistance, voltage resistance,
The present invention relates to an epoxy resin composition with improved mechanical properties, good adhesiveness, and insulation properties.

0002

[Prior Art] In recent years, flexible wiring boards and circuit boards, which are constructed by bonding metal foil to a base material, have been developed from the viewpoint of heat dissipation, electromagnetic shielding, heat resistance, reduction of circuit space, etc. Circuit boards and the like have been widely used. These are base materials such as polyimide resin plates, glass epoxy substrates with glass fibers impregnated with epoxy resin, etc., and substrates with insulating layers on metal plates, etc., with metal foil provided on them and circuits formed by etching. There are known devices in which a circuit is directly plated onto a substrate, or a circuit is printed with conductive resin.

0003

Problems to be Solved by the Invention Among these wiring boards formed by bonding copper foil to a base material, epoxy resin is widely used as an insulating adhesive material. However, although epoxy resin has excellent insulation, heat resistance, and adhesive properties, it is brittle and can crack due to thermal shock, peel off due to external impact, generate smear when through-hole, and crack when bent due to insufficient flexibility. There are problems such as being easy to use. Conventionally, problems such as thermal shock, external mechanical shock, and lack of flexibility have been solved by adding rubber-like substances to epoxy resin. In addition to a decrease in heat resistance and a decrease in adhesion after high-temperature heating, problems such as smear generation also occur as in the past.

0004

[Means for Solving the Problems] As a result of extensive research to solve the above problems, the present inventors have discovered that at least an epoxy resin, a polyfunctional phenol compound, an imidazole compound and a phenolic hydroxyl group represented by the general formula (1) It has been found that an epoxy resin composition for wiring boards containing an aramid-polybutadiene-acrylonitrile block copolymer is useful for wiring boards.

[Formula 2] (where x = integer from 3 to 7, y = integer from 1 to 4, y/(x
+y) = 0.1 to 0.3, z = integer of 5 to 15, m = 1
~400 integer, n=1~400 integer, n/(m+n
) = 0.01 to 0.50, l = integer of 1 to 50, Ar1
, Ar3 is a divalent aromatic group, Ar2 is a divalent aromatic group containing a phenolic hydroxyl group)

0005
] By introducing the phenolic hydroxyl group-containing aramid-polybutadiene-acrylonitrile block copolymer represented by the above general formula (1) into an epoxy resin, toughness can be improved without reducing heat resistance. It has been found that cracking and peeling caused by external impact, as well as bending strength, etc. can be improved. In addition, this copolymer can achieve high effects even when added in small amounts, so not only does it not impair the insulation properties of epoxy resin, but the polybutadiene-acrylonitrile component in this copolymer can be added to the epoxy matrix with micronization. Since it exists in small quantities with the following sizes, it is presumed that it not only improves smear generation but also acts as a stress reliever against heat and external impact. Furthermore, the aramid component in this copolymer is dispersed in molecular form in the epoxy resin, which not only improves the toughness of the epoxy matrix but also improves its heat resistance. Furthermore, since the polybutadiene-acrylonitrile component is fixed to this aramid component, there is no bleeding out due to heating, and there is little change in adhesive strength due to thermal cycles. Furthermore, by using a novolac type phenolic resin as the polyfunctional phenolic compound, the bending strength at high temperatures is further improved. As a result of the above, the wiring board using the epoxy resin composition of the present invention as an insulating layer has a remarkable improvement effect that has not been seen before.

The epoxy resin used in the present invention may be any epoxy resin as long as it has at least two epoxy groups in one molecule, such as glycidyl ethers, glycidyl Examples include epoxy resins such as esters, glycidyl amines, linear aliphatic epoxides, alicyclic epoxides, and hydantoin type epoxides. Examples of the glycidyl ethers include glycidyl ether of bisphenol, polyglycidyl ether of phenol novolak, glycidyl ether of alkylene glycol or polyalkylene glycol, and the like. The glycidyl ethers of bisphenol include bisphenol A, bisphenol F, bisphenol AD, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F, tetramethylbisphenol AD, tetramethylbisphenol S,
Examples include diglycidyl ethers of dihydric phenols such as tetrachlorobisphenol A and tetrabromobisphenol A, and examples of polyglycidyl ethers of phenol novolacs include polyglycidyl ethers of novolak resins such as phenol novolak, cresol novolac, and brominated phenol novolak. Examples of diglycidyl ethers of alkylene glycols or polyalkylene glycols include diglycidyl ethers of glycols such as polyethylene glycol, polypropylene glycol, and butanediol. Examples of the glycidyl esters include hexahydrophthalic acid glycidyl ester and dimer acid glycidyl ester, and examples of the glycidyl amines include triglycidyl amino diphenylmethane, triglycidylaminophenol, and triglycidyl isocyanurate. can be mentioned. Further, examples of linear aliphatic epoxides include epoxidized polybutadiene and epoxidized soybean oil, and examples of alicyclic epoxides include 3,4-epoxy-6-methylcyclohexylmethylcarboxylate, 3, Examples include 4-epoxycyclohexylmethylcarboxylate and hydrogenated bisphenol epoxy. Examples of hydantoin-type epoxies include diglycidylhydantoin, glycidylglycidoxyalkylhydantoin, and the like.

The polyfunctional phenol compound used as a curing agent in the present invention may be any compound as long as it has two or more functional groups in one molecule and can form a molecular chain with the epoxy resin. 2'-bis(4-hydroxyphenyl)propane, 2,2'-bis(2-methyl-4
-hydroxyphenyl)propane, 2,2'-bis(4
-hydroxyphenyl)methane, 1,1'-bis(4-
hydroxyphenyl)ethane, 1,1'-bis(4-hydroxyphenyl)hexane, 1,1'-bis(4-hydroxyphenyl)docosyl, 2,2'-bis(4-hydroxyphenyl)butane, 2,2 '-Bis(4-hydroxyphenyl)hexane, bis(4-hydroxyphenyl)sulfone, bis(3-chloro-4-hydroxyphenyl)sulfone, bis(3,5-dimethyl-4-
hydroxyphenyl) sulfone, bis(4-hydroxy-3,5-dibromophenyl) sulfone, bis(4
-hydroxyphenyl) sulfide, bis(3-methyl-4-hydroxyphenyl) sulfide, 1,1-bis(4-hydroxyphenyl)cyclohexane, 4,4'
-Dihydroxybenzophenone, dihydroxynaphthalene, 1,4-(p-hydroxycumyl)benzene, or novolak resins such as phenol, cresol, alkylphenol, catechol, bisphenol A, and bisphenol F, and halogenated products of these phenol resins. . Several types of these phenol compounds can also be used in combination. From the viewpoint of drill workability, it is preferable that the amount of phenol hydroxyl group added is in the range of 0.5 to 1.5 equivalents based on the epoxy resin. In the present invention, novolac type phenolic resin is preferred because it provides high bending strength at high temperatures.

The epoxy resin composition for wiring bases of the present invention contains an imidazole compound as a curing accelerator. The imidazole compounds include imidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 1-benzyl-2-methylimidazole, 2-heptadecylimidazole, and 2-isopropyl. Imidazole, 2,4-dimethylimidazole, 2-phenyl-4
-Methylimidazole, 2-methylimidazoline, 2-
Ethylimidazoline, 2-isopropylimidazoline,
2-phenylimidazoline, 2-undecylimidazoline, 2,4-dimethylimidazoline, 2-phenyl-4
-Methylimidazoline, etc., or compounds masking these may be mentioned. Examples of the masking agent include acrylonitrile, phenylene diisocyanate, tolylene diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, methylene dibisphenyl isocyanate, and melamine acrylate. Several types of these curing accelerators may be used in combination, and the blending amount is preferably 0.01 to 10% by weight based on the epoxy resin.

Block copolymer (1) used in the present invention
can be synthesized by the following method. That is, the divalent aromatic group Ar2 having a phenolic hydroxyl group in general formula (1)
An excess amount of the aromatic dicarboxylic acid having the divalent aromatic group Ar1 in the general formula (1) and no phenolic hydroxyl group,
Add an aromatic diamine having a divalent aromatic group Ar3 into 1), and add these to, for example, an organic solvent represented by N-methyl-2-pyrrolidone in the presence of a phosphite ester and a pyridine derivative. Heat and stir under an inert atmosphere such as nitrogen. A polybutadiene-acrylonitrile copolymer having carboxyl groups at both ends is added to the resulting polyaramid oligomer solution containing aminoaryl groups at both ends, and polycondensation is performed to form a block copolymer. can get.

Examples of the dicarboxylic acids having a phenolic hydroxyl group include 5-hydroxyisophthalic acid and 4-hydroxyisophthalic acid.
Hydroxyisophthalic acid, 2-hydroxyphthalic acid, 3
-Hydroxyphthalic acid, 2-hydroxyterephthalic acid, and specific examples of the dicarboxylic acids without phenolic hydroxyl groups include phthalic acid, isophthalic acid, terephthalic acid, 4,4'-biphenyldicarboxylic acid, 3,
3'-methylene dibenzoic acid, 4,4'-methylene dibenzoic acid, 4,4'-oxydibenzoic acid, 4,4'-thiodibenzoic acid, 3,3'-carbonyl dibenzoic acid, 4, 4'
- Carbonyl dibenzoic acid, 4,4'-sulfonyl dibenzoic acid, 1,4-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, etc., but are limited to these. It's not a thing.

Further, specific examples of the aromatic diamine include m-phenylene diamine, p-phenylene diamine,
Metatolylene diamine, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4
'-Diaminodiphenylthioether, 3,3'-dimethyl-4,4'-diaminodiphenylthioether, 3
, 3'-diethoxy-4,4'-diaminodiphenylthioether, 3,3'-diaminodiphenylthioether, 4,4'-diaminobenzophenone, 3,3'-dimethyl-4,4'-diaminobenzophenone, 3,3 '
-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,3'-dimethoxy-4,4'-diaminodiphenylmethane, 2,2'-bis(3-aminophenyl)propane, 2,2'-bis(4- aminophenyl)propane, 4,4'-diaminodiphenylsulfoxide, 4,4'-diaminodiphenylsulfone, benzidine, 3,3'-dimethylbenzidine, 3,3'-dimethoxybenzidine, 3,3'-diaminobiphenyl, p
-xylylene diamine, m-xylylene diamine, etc., and these can be used alone or in combination.

[0012] In addition, a polybutadiene-acrylonitrile copolymer having carboxyl groups at both ends is produced by Goodri
It is commercially available as Hycar CTBN from ch company, and these can be used.

The epoxy resin composition used as the insulating layer for a printed wiring board of the present invention may contain a coupling agent, a coloring agent such as a dye or a pigment, an oxidation stabilizer, a light stabilizer, and the like.

Examples of the coupling agent include silane coupling agents such as γ-glycidoxypropyltrimethoxysilane and γ-glycidoxypropyltriethoxysilane;
The adhesion to the copper foil can be further strengthened by using a titanate coupling agent such as isopropyl triisostearoyl titanate or isopropyl tridodecylbenzenesulfonyl titanate.

[0015] As a method for producing the epoxy resin composition of the present invention used as an insulating layer for a printed wiring board, the above epoxy resin, a polyfunctional phenol compound, a compound of the general formula (1
) and other necessary imidazole compounds such as acetone, methyl ethyl ketone, toluene, N,N-dimethylformamide, N,N-dimethylacetamide, N
- After dissolving in a solvent such as methyl-2-pyrrolidone and making it into a varnish and applying it to a base material or impregnating it into fibers,
A wiring board prepreg is produced by heat drying at a temperature of ~200°C. At that time, a part of the epoxy resin and the general formula (1)
A reaction product consisting of a modified epoxy resin is created by reacting a block copolymer of The method of dissolving it in the above-mentioned solvent to form a varnish is preferred in order to obtain strong adhesive performance. Further details of the reaction product are as follows. That is, the reaction between the epoxy group of the epoxy resin of the present invention and the phenolic hydroxyl group of the block copolymer can be carried out in an amide solvent to obtain a reaction product. As the amide solvent, N,
N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, etc. are used. The amount of epoxy resin used is 1 to 1 to 1 for the block copolymer.
The amount is 20 times equivalent, preferably 5 to 15 times equivalent. The reaction temperature is 50°C or higher, preferably 70°C. The amount of the block copolymer used is preferably 1 to 15% by weight based on the total poxy resin contained in the epoxy resin composition for wiring boards of the present invention. Even if it is added in an amount exceeding 15% by weight, it is not preferable because a large coating film toughness or Erichsen performance cannot be obtained. Furthermore, the printed wiring board of the present invention can be manufactured by bonding copper foil to this prepreg or a prepreg obtained by further laminating this prepreg by heating and pressurizing it. It is also possible to use a liquid epoxy resin to coat a base material or impregnate fibers with a solvent-free epoxy resin composition in which these compounds are dissolved.

[0016] As the base material to which this epoxy resin composition is applied or impregnated, polyimide resin represented by Kapton, aluminum substrate, etc. are used, and as the fiber, cellulose fiber, glass fiber, aramid fiber, carbon fiber, etc. are used. used.

[0017]

[Examples] The present invention will be further explained below with reference to Examples, but the present invention is not limited thereto. Synthesis Example 1 Synthesis of phenolic hydroxyl group-containing aramid-polybutadiene-acrylonitrile block copolymer (2 mol% of phenolic hydroxyl groups contained in the aramid part); 19.60 g (118 mmol) of isophthalic acid, 3,4'-oxydianiline 26.4 g (132 mmol), 0.41 g (2.3 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 in 4 liters. Pour into a round-bottomed flask and stir to dissolve, then add 74 g of triphenyl phosphite and add 90 g of triphenyl phosphite.
The mixture was reacted at ℃ for 4 hours to produce a phenolic hydroxyl group-containing aramid oligomer. In addition, polybutadiene-acrylonitrile copolymer having carboxyl groups at both ends (Hycar CTBN, BF Goodric
Manufactured by Company H: The acrylonitrile component contained in the polybutadiene acrylonitrile part is 17 mol%, and the molecular weight is approximately 36.
00) Add a solution of 48 g dissolved in 240 ml of pyridine, react for another 4 hours, cool to room temperature, and add this reaction solution to 20 liters of methanol to prepare the polybutadiene-acrylonitrile copolymer used in the present invention. Approximately 2 mol% of phenolic hydroxyl groups with a content of 50% by weight
The aramid-polybutadiene-acrylonitrile block copolymer contained therein was precipitated. This precipitated polymer was further purified by methanol washing and methanol reflux. The intrinsic viscosity of this polymer was 0.85 dl/g (dimethylacetamide, 30°C). When the infrared spectrum of the polymer powder was measured using the diffuse reflection method, it was found that 1674
Amidocarbonyl group at cm-1, 2856-2975
An absorption based on the C-H bond of the butadiene moiety was observed at cm-1, and an absorption based on the nitrile group was observed at 2245 cm-1.

Synthesis Example 2 Synthesis of phenolic hydroxyl group-containing aramid-polybutadiene-acrylonitrile block copolymer (14 mol% of phenolic hydroxyl groups contained in the aramid part); Synthesis Example 1
, 19.93 g (120 mmo
l), 30.68 g (1
53 mmol), 3.6 5-hydroxyisophthalic acid
4 (20 mmol), polybutadiene-acrylonitrile copolymer with carboxyl groups at both ends (Hycar
CTBN, manufactured by BF Goodrich. Polymerization was carried out in the same manner as in Synthesis Example 1, except that the acrylonitrile contained in the polybutadiene acrylonitrile portion was 17 mol % and the molecular weight was approximately 3600) was replaced with 55.5 g.
A similar post-treatment was performed to precipitate an aramid-polybutadiene-acrylonitrile block copolymer containing about 14 mol% of phenolic hydroxyl groups used in the present invention. The intrinsic viscosity of this polymer was 0.82 dl/g (dimethylacetamide, 30°C). When the infrared spectrum of the polymer powder was measured using the diffuse reflection method, it was found that 1675
Amidocarbonyl group at cm-1, 2854-2971
An absorption based on the C-H bond of the butadiene moiety was observed at cm-1, and an absorption based on the nitrile group was observed at 2243 cm-1.

<Production of reaction product (A) between epoxy resin and block copolymer> 200 g of dimethylformamide
2 mol% of the phenolic hydroxyl group obtained in Synthesis Example 1 in
After dissolving 24 g of the contained phenolic hydroxyl group-containing aramidopolybutadiene acrylonitrile block copolymer, epoxy resin (AER667, bisphenol A epoxy resin, average molecular weight: 2600, epoxy equivalent: 2000, manufactured by Asahi Kasei Corporation) 5 .7 g and 0.08 g of triphenylphosphine as a reaction accelerator were added, and the mixture was reacted at 90° C. for 2 hours. This was added to water to precipitate the resin, washed repeatedly with warm water, and then tetrahydrofuran was added to azeotrope these solvents under reduced pressure.
It was vacuum dried to obtain a reaction product (A) in which the epoxy resin reacted with the aramid part. To a solution in which 1 mg of this reaction product (A) was dissolved in about 30 ml of pyridine, 1 g of anhydrous chloride-iron (trivalent) was dissolved in 100 ml of chloroform, and 8 ml of pyridine was added. (obtained by filtering the precipitate and preparing a red solution) was added and stirred, but no discoloration was observed; all the phenolic hydroxyl groups in this resin had reacted with the glycidyl groups, and no unreacted It was confirmed that no phenol residues were contained.

<Production of reaction product (B) of epoxy resin and block copolymer> 24 g of the aramidopolybutadiene acrylonitrile block copolymer containing about 14 mol% of phenolic hydroxyl groups obtained in Synthesis Example 2, epoxy Resin 14.4 (AER667, bisphenol A type epoxy resin, average molecular weight: 2600, epoxy equivalent: 2
000, manufactured by Asahi Kasei Industries, Ltd.), 0.6 mg of triphenylphosphine, a curing agent, was added with dimethylformamide 2
A reaction product (B) of an aramid-polybutadiene acrylonitrile block copolymer and an epoxy resin was obtained by dissolving the mixture in 0.0 g and performing the same operation as in Resin Composition Example 1. To a solution of 1 mg of this reaction product (B) dissolved in about 30 ml of pyridine, 1 g of anhydrous iron chloride (trivalent), anhydrous iron chloride (trivalent), was dissolved in 100 ml of chloroform, and 8 ml of pyridine was added, followed by precipitation. A few drops of the red solution (obtained by filtering the substance and preparing a red solution) were added and stirred, but no discoloration was observed; all the phenolic hydroxyl groups in this resin reacted with the glycidyl groups, and unreacted phenol remained. It was confirmed that no groups were contained.

Example 1 Brominated bisphenol A type epoxy resin (epoxy equivalent: 550) 77g Reaction product (A)

10g phenol novolac type epoxy resin (epoxy equivalent: 20
0) 20g phenol novolak resin

30g ethylamine hydrochloride
2g
γ-glycidoxypropyltrimethoxysilane
2g 1-
Cyanoethyl-2-phenylimidazole
0.2 g of each of the above compounds was dissolved in methyl ethyl ketone to prepare a varnish with a nonvolatile content of 60%. Apply this varnish to a thickness of 1 mm and a size of 50 x 50
A prepreg was obtained by impregnating a glass cloth with a diameter of 1.0 mm and then heating and drying it at 130° C. for 10 minutes.

Example 2 Example 1 was completely repeated, except that 10 g of the reaction product (A) used in Example 1 was replaced with 15 g of the reaction product (B), and 77 g of the brominated bisphenol A epoxy resin was replaced with 75 g. I got prepug in the same way.

Example 3 Same as Example 1 except that 10 g of the reaction product (A) used in Example 1 was replaced with 30 g of the reaction product (B), and 77 g of the brominated bisphenol A epoxy resin was replaced with 65 g. Prepreg was obtained in exactly the same way.

Example 4 Brominated bisphenol A type epoxy resin (epoxy equivalent: 530) 75g Reaction product (B)

15g phenol novolac type epoxy resin (epoxy equivalent: 20
0) 20g phenol novolak resin

30g ethylamine hydrochloride
2g
γ-glycidoxypropyltrimethoxysilane
2g 1-
Cyanoethyl-2-phenylimidazole
0.2 g of the above compound was dissolved in N-dimethylacetamide to prepare a varnish with a nonvolatile content of 25%. This varnish has a thickness of 125 μm and a size of 5
After coating on a 0x50 mm Kapton, it was heated and dried at 130°C for 10 minutes to obtain a prepreg.

Example 5 15 g of the reaction product (B) used in Example 4 was
A prepreg was obtained in exactly the same manner as in Example 4, except that 0 g of the brominated bisphenol A type epoxy resin was replaced with 65 g of the brominated bisphenol A epoxy resin.

Comparative Example 1 In addition to the reaction product (A) used in Example 1, 75 g of brominated bisphenol A type epoxy resin was added to 8
A prepreg was obtained in the same manner as in Example 1 except that the amount was changed to 0 g.

Comparative Example 2 In addition to the reaction product (B) used in Example 4, 75 g of brominated bisphenol A type epoxy resin was added to 8
A prepreg was obtained in the same manner as in Example 4 except that the amount was changed to 0 g.

Comparative Example 3 In addition to the reaction product (B) used in Example 4, 75 g of brominated bisphenol A type epoxy resin was added to 8
A prepreg was obtained in the same manner as in Example 4, except that 30 g of the phenol novolac resin was replaced with 4 g of dicyamine diamide.

[0029] Three prepreg sheets obtained in Examples 1 to 3 and Comparative Example 1 and a copper foil 2 with a thickness of 35 μm and a size of 50 x 50 mm.
170℃, 100 minutes, 50kg/cm2
A copper-clad laminate was produced by heating and pressing under the following conditions. Further, the prepreg described above was laminated on both sides of this copper-clad laminate under the same conditions, and heated and pressed to produce a three-layer wiring board. or,
The same 35 μm copper foil was laminated on the prepreg formed on Kapton obtained in Examples 4 and 5 and Comparative Examples 2 and 3, and heated at 170°C.
A copper-clad laminate was produced by heating and pressing under the conditions of 100 minutes and 50 kg/cm2. These copper foil circuit wiring boards were subjected to observation of smear occurrence rate, measurement of copper foil peeling strength, and bending test. These results are shown in Table 1. Evaluation of smear occurrence rate: Through-hole plating was applied to a drilled wiring board, and the connection between the inner layer copper of the hole and the through-hole plated copper was observed using a microscope on the cut surface of the through-hole section, and the occurrence of smear was investigated. (This was carried out only for the samples of Examples 1 to 3 and Comparative Example 1). Copper foil peel strength evaluation: A 1 mm wide line was formed on the copper foil on the wiring board. This line uses a negative dry film (manufactured by Hoechst, OZAPECF52) on the copper foil on the board.
5) were bonded together, exposed, developed, and etched with 40 Bё of ferric chloride aqueous solution. 90 of that line
The peel strength in the degree direction was measured at a peel rate of 50 mm/min (measured for the samples of Examples 1 to 5 and Comparative Examples 1 to 3). In Table 1, normal temperature means 25°C, and heating means after heat treatment at 155°C for 240 hours. Bending test: The circuit board was bent 180 degrees, and an evaluation of pass or fail was made based on whether or not a crack was formed at the bent part (this was done on samples of Examples 4 and 5 and Comparative Examples 2 and 3). ).

[0030]

[Table 1]

Effects of the Invention A wiring board having an insulating layer made of the epoxy resin composition of the present invention can be suitably used because it causes less smearing and has strong adhesion to copper foil and toughness.

Claims (1)

[Claims] Claim 1: At least an epoxy resin, a polyfunctional phenol compound, an imidazole compound, and the general formula (1)
An epoxy resin composition for a wiring board, comprising a phenolic hydroxyl group-containing aramid-polybutadiene-acrylonitrile block copolymer. [Formula 1] (where x = integer from 3 to 7, y = integer from 1 to 4, y/(x
+y) = 0.1 to 0.3, z = integer of 5 to 15, m = 1
~400 integer, n=1~400 integer, n/(m+n
) = 0.01 to 0.50, l = integer of 1 to 50, Ar1
, Ar3 represents a divalent aromatic group, Ar2 represents a divalent aromatic group containing a phenolic hydroxyl group) [Claim 2
10. The epoxy resin composition for wiring boards according to claim 1, wherein the polyfunctional phenol compound is a novolac type phenol resin.