JP7132784B2 - Epoxy resin composition, prepreg, laminate and printed wiring board - Google Patents

Description

TECHNICAL FIELD The present invention relates to an epoxy resin composition for prepregs, prepregs, laminates, and printed wiring boards that are used in the production of printed wiring boards and multilayer printed wiring boards that are excellent in low dielectric properties and high adhesiveness.

Epoxy resins are excellent in adhesiveness, flexibility, heat resistance, chemical resistance, insulation properties, and curing reactivity, so they are used in a wide variety of applications such as coatings, adhesion to civil engineering, casting, electrical and electronic materials, and film materials. In particular, it is widely used for printed wiring boards, which is one of electrical and electronic materials, by imparting flame retardancy to epoxy resins.

2. Description of the Related Art In recent years, the miniaturization and performance enhancement of information equipment are progressing rapidly, and along with this, materials used in the fields of semiconductors and electronic parts are required to have higher performance than ever before. In particular, from the viewpoint of reliability, epoxy resin compositions, which are used as materials for electrical and electronic parts, are required to have high heat resistance with a glass transition temperature of 150° C. or higher and low dielectric properties as substrates become thinner and more functional. ing.

As shown in Patent Document 1, a dicyclopentadiene phenol resin or the like into which an aliphatic skeleton is introduced as a linking group has hitherto been used to reduce the dielectric constant for use in circuit boards. Although various phenols have been exemplified, only unsubstituted phenols have been verified for effectiveness. Sexually, it wasn't satisfying either.

As a resin for obtaining a low dielectric loss tangent, as shown in Patent Document 2, an aromatic modified epoxy resin or the like having an aromatic skeleton introduced has been used. There was a problem, and there was a demand for the development of a resin that has a low dielectric loss tangent and high adhesive strength.

As shown above, none of the epoxy resins disclosed in these documents satisfactorily satisfies the performance requirements based on recent advances in functionality, and was insufficient to ensure low dielectric properties and adhesiveness. .

On the other hand, the 2,6-disubstituted phenol/dicyclopentadiene type resin disclosed in Patent Document 3 has been used for sealing applications because of its low viscosity. Although the application to a circuit board is also described, there is no specific example applied to that application, nor is there any description of an epoxy resin composition suitable for that application.

Japanese Patent Application Laid-Open No. 2001-240654 JP 2015-187190 A JP-A-5-339341

Accordingly, the problem to be solved by the present invention is to provide an epoxy resin composition that exhibits excellent low dielectric properties in a cured product and that exhibits excellent copper foil peel strength and interlayer adhesion when used for printed wiring boards. It is in.

In order to solve the above problems, the present inventors have found that when using a resin obtained by epoxidizing a dicyclopentadiene type phenol resin obtained by reacting a 2,6-disubstituted phenol with dicyclopentadiene, The inventors have found that the resulting cured product has excellent low dielectric properties and adhesiveness, and completed the present invention.

That is, the present invention is an epoxy resin composition for a circuit board comprising an epoxy resin and a curing agent as essential components, wherein at least 10% by mass of the epoxy resin is an epoxy resin represented by the following general formula (1). It is an epoxy resin composition for circuit boards.

式中、Ｒは炭素数１～８のアルキル基、フェニル基またはアリル基を示し、ｎは平均値で０～１０の数を示す。

In the formula, R represents an alkyl group having 1 to 8 carbon atoms, a phenyl group or an allyl group, and n represents an average number of 0 to 10.

The epoxy resin of the 2,6-disubstituted phenol/dicyclopentadiene type epoxy resin has an epoxy equivalent of 244 to 3700 g/eq. is suitable as the epoxy resin for the epoxy resin composition for circuit boards.

The above curing agent is preferably a phenolic resin curing agent.

The present invention also provides a cured product obtained by curing the above epoxy resin composition, and a prepreg, laminate, or printed wiring board using the above epoxy resin composition.

The epoxy resin composition of the present invention exhibits excellent low dielectric properties in its cured product, and is suitable as a curing agent that provides epoxy resin compositions with excellent copper foil peel strength and interlayer adhesion strength for use in printed wiring boards. used for In particular, it can be suitably used for mobile applications and server applications where low dielectric properties are strongly required.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail.
The epoxy resin composition of the present invention contains an epoxy resin and a curing agent as essential components. At least 10% by mass or more of the epoxy resin is the epoxy resin represented by the general formula (1).

In general formula (1), R represents an alkyl group having 1 to 8 carbon atoms, a phenyl group or an allyl group. Examples of alkyl groups having 1 to 8 carbon atoms include carbonized groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, isobutyl group, t-butyl group and hexyl group. Examples include, but are not limited to, a hydrogen group and a cycloalkyl group having 5 to 6 carbon atoms such as a cyclohexyl group. A methyl group is preferable from the viewpoint of availability and reactivity when a cured product is obtained.

n is the number of repetitions and represents an average value of 0 to 10, preferably 0.05 to 5, more preferably 0.1 to 3.5, further preferably 0.2 to 1, and 0.25 ~0.5 is particularly preferred.

The epoxy resin is prepared by first reacting a 2,6-disubstituted phenol compound and dicyclopentadiene in the presence of a catalyst such as boron trifluoride-ether complex, and is represented by the following general formula (2). Synthesize a diphenol compound. Then, it can be obtained by reacting the obtained diphenol compound with an epihalohydrin such as epichlorohydrin to epoxidize it.

一般式（２）において、Ｒは一般式（１）のＲと同義である。

In general formula (2), R has the same definition as R in general formula (1).

The diphenol compound represented by the general formula (2) is obtained by adding preferably 2 to 15 mol, more preferably 3 to 12 mol, of dicyclopentadiene to 1 mol of the 2,6-disubstituted phenol compound, and It can be obtained by reacting in the presence.

The raw material phenols of the diphenol compound represented by the general formula (2) include 2,6-dimethylphenol, 2,6-diethylphenol, 2,6-dipropylphenol, 2,6-diisopropylphenol, 2 ,6-di(n-butyl)phenol, 2,6-di(t-butyl)phenol, 2,6-dihexylphenol, 2,6-dicyclohexylphenol, 2,6-diphenylphenol and the like. 2,6-dimethylphenol is preferred from the viewpoint of ease of curing and reactivity when a cured product is obtained.

The acid catalyst used when reacting phenols and dicyclopentadiene is a Lewis acid. Boron fluoride compounds, metal chlorides such as aluminum chloride, tin chloride, zinc chloride, titanium tetrachloride and iron chloride, and organic sulfonic acids such as methanesulfonic acid, ethanesulfonic acid and propanesulfonic acid, among others. A boron trifluoride-ether complex is preferred because of its ease of handling. The acid catalyst is used in an amount of 0.001 to 20 parts by mass, preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of dicyclopentadiene in the case of boron trifluoride-ether complex.

As a reaction method, a system in which a 2,6-disubstituted phenol and a catalyst are charged in a reactor and dicyclopentadiene is added dropwise over 1 to 10 hours is preferred.

The reaction temperature is 50 to 200° C., and the reaction time is 1 to 10 hours.

After completion of the reaction, an alkali such as sodium hydroxide or potassium hydroxide is added to deactivate the catalyst, and unreacted 2,6-disubstituted phenol is recovered under reduced pressure.

Thereafter, in order to separate and purify the reaction product, a solvent such as toluene, xylene, methyl ethyl ketone, or methyl isobutyl ketone is added to dissolve the product, washed with water, and the solvent is recovered under reduced pressure to obtain the desired diphenol compound. Obtainable.

Also in the reaction, a solvent such as benzene, toluene, xylene, chlorobenzene, dichlorobenzene, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether may be used as necessary for viscosity adjustment.

The epoxy resin used in the present invention is obtained by reacting the diphenol compound obtained by the above method with epihalohydrin. This reaction is carried out according to a conventionally known method.

For example, an alkali metal hydroxide such as sodium hydroxide is added as a solid or a concentrated aqueous solution to a mixture of a diphenol compound and epihalohydrin in excess moles relative to the hydroxyl groups of the diphenol compound, and the mixture is reacted at a reaction temperature of 30 to 120°C. It can be obtained by reacting for 0.5 to 10 hours, or by adding a quaternary ammonium salt such as tetraethylammonium chloride to a diphenol compound and excess moles of epihalohydrin as a catalyst and reacting at a temperature of 50 to 150° C. for 1 to 5 hours. It can be obtained by adding an alkali metal hydroxide such as sodium hydroxide as a solid or a concentrated aqueous solution to a polyhalohydrin ether and reacting it at a temperature of 30 to 120° C. for 1 to 10 hours.

In the above reaction, the amount of epihalohydrin used is 1 to 10 times, preferably 2 to 5 times, the molar amount of the hydroxyl group of the diphenol compound, and the amount of the alkali metal hydroxide used is the amount of the diphenol compound. It is in the range of 0.85 to 1.1 times the moles of hydroxyl groups.

Since the epoxy resin obtained by these reactions contains unreacted epihalohydrin and alkali metal halide, the unreacted epihalohydrin is removed from the reaction mixture by evaporation, and the alkali metal halide is extracted with water. , the desired epoxy resin can be obtained by removing by a method such as filtering.

The epoxy equivalent (g/eq.) of the dicyclopentadiene type epoxy resin is preferably from 244 to 3700, more preferably from 260 to 2000, more preferably more than 270 and less than 700. Especially when dicyandiamide is used as a curing agent, crystals of dicyandiamide are deposited on the prepreg, so the epoxy equivalent is preferably 300 or more.

The molecular weight distribution of the obtained epoxy resin can be changed by changing the charging ratio of the diphenol compound and epihalohydrin during the epoxidation reaction, and the amount of epihalohydrin used is brought close to equimolar to the hydroxyl group of the diphenol compound. The higher the molecular weight distribution, the lower the molecular weight distribution. Moreover, it is also possible to increase the molecular weight of the obtained epoxy resin by reacting the diphenol compound again.

By using such an epoxy resin, the epoxy resin composition aimed at by the present invention can be obtained.

As the epoxy resin used to obtain the epoxy resin composition of the present invention, in addition to the above dicyclopentadiene type epoxy resin, one or two or more of various epoxy resins may be used in combination, if necessary. When these other epoxy resins are used together, it is preferably 70% by mass or less, more preferably 50% by mass or less, of the total epoxy resin. If too much epoxy resin is used in combination, the dielectric properties of the epoxy resin composition may deteriorate.

Usual epoxy resins having two or more epoxy groups in the molecule can be used as the epoxy resins used in combination. Examples include bisphenol A type epoxy resin, bisphenol F type epoxy resin, tetramethylbisphenol F type epoxy resin, hydroquinone type epoxy resin, biphenyl type epoxy resin, bisphenol fluorene type epoxy resin, bisphenol S type epoxy resin, bisthioether type epoxy resin. Epoxy resin, resorcinol type epoxy resin, biphenylaralkylphenol type epoxy resin, naphthalene diol type epoxy resin, phenol novolac type epoxy resin, aromatic modified phenol novolac type epoxy resin, cresol novolak type epoxy resin, alkyl novolak type epoxy resin, bisphenol novolak type epoxy resin, naphthol novolak type epoxy resin, β-naphthol aralkyl type epoxy resin, dinaphthol aralkyl type epoxy resin, α-naphthol aralkyl type epoxy resin, trisphenylmethane type epoxy resin, alkylene glycol type epoxy resin, aliphatic cyclic epoxy Examples include, but are not limited to, resins, diaminodiphenylmethane tetraglycidylamine, aminophenol-type epoxy resins, phosphorus-containing epoxy resins, urethane-modified epoxy resins, and oxazolidone ring-containing epoxy resins. From the viewpoint of availability, naphthalenediol type epoxy resin, phenol novolak type epoxy resin, aromatic modified phenol novolak type epoxy resin, cresol novolak type epoxy resin, α-naphthol aralkyl type epoxy resin, other dicyclopentadiene type epoxy resins. , phosphorus-containing epoxy resins, oxazolidone ring-containing epoxy resins, and the like are preferred.

The epoxy resin composition of the present invention can be cured with conventional known curing agents. Curing agents that can be used include commonly used curing agents such as phenolic resin curing agents, acid anhydride curing agents, amine curing agents, and other curing agents. may be used, or two or more types may be used in combination.

The amount of the curing agent used in the epoxy resin composition is in the range of 0.2 mol or more and 1.5 mol or less of the active hydrogen group of the curing agent per 1 mol of the epoxy groups of the entire epoxy resin. If the active hydrogen group is less than 0.2 mol or more than 1.5 mol per 1 mol of epoxy group, curing may be incomplete and good cured physical properties may not be obtained. A preferable range is 0.3 mol or more and 1.5 mol or less, a more preferable range is 0.5 mol or more and 1.5 mol or less, and a further preferable range is 0.8 mol or more and 1.2 mol or less. For example, when using a phenol resin-based curing agent or an amine-based curing agent, an active hydrogen group is blended in an almost equimolar amount with respect to the epoxy group, and when an acid anhydride-based curing agent is used, per 1 mol of the epoxy group 0.5 to 1.2 mol, preferably 0.6 to 1.0 mol, of the acid anhydride group is blended.

The term "active hydrogen group" as used in the present invention means a functional group having an active hydrogen reactive with an epoxy group (including a functional group having a latent active hydrogen that generates an active hydrogen by hydrolysis, etc., and a functional group that exhibits an equivalent curing effect). ), and specific examples include an acid anhydride group, a carboxyl group, an amino group, a phenolic hydroxyl group, and the like. Regarding active hydrogen groups, 1 mol of carboxyl group and phenolic hydroxyl group is calculated as 1 mol, and amino group (NH ₂ ) is calculated as 2 mol. Moreover, when the active hydrogen group is not clear, the active hydrogen equivalent can be determined by measurement. For example, by reacting a monoepoxy resin such as phenyl glycidyl ether with a known epoxy equivalent with a curing agent with an unknown active hydrogen equivalent and measuring the amount of monoepoxy resin consumed, the active hydrogen equivalent of the curing agent used can be asked for.

Specific examples of phenolic resin curing agents include bisphenol A, bisphenol F, bisphenol C, bisphenol K, bisphenol Z, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F, tetramethylbisphenol S, and tetramethylbisphenol Z. , dihydroxydiphenyl sulfide, bisphenols such as 4,4'-thiobis(3-methyl-6-t-butylphenol), catechol, resorcinol, methylresorcinol, hydroquinone, monomethylhydroquinone, dimethylhydroquinone, trimethylhydroquinone, mono-t- Dihydroxybenzenes such as butylhydroquinone and di-t-butylhydroquinone, hydroxynaphthalenes such as dihydroxynaphthalene, dihydroxymethylnaphthalene, and trihydroxynaphthalene, phosphorus-containing phenolic curing agents such as LC-950PM60 (manufactured by Shin-AT&C), and , Shaunol BRG-555 (manufactured by Aica Kogyo Co., Ltd.) and other phenol novolak resins, DC-5 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) and other cresol novolak resins, aromatic modified phenol novolac resins, bisphenol A novolak resins, Resitop TPM -100 (manufactured by Gun Ei Chemical Industry Co., Ltd.) trishydroxyphenylmethane type novolac resin, phenols such as naphthol novolac resin, naphthols and / or condensates of bisphenols and aldehydes, SN-160, SN- 395, SN-485 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) and other phenols, condensates of naphthols and/or bisphenols and xylylene glycol, condensates of phenols and/or naphthols and isopropenylacetophenone, Reaction products of phenols, naphthols and/or bisphenols with dicyclopentadiene, condensates of phenols, naphthols and/or bisphenols and biphenyl-based cross-linking agents, etc., so-called "novolac-type phenolic resins" A phenol compound etc. are mentioned. Phenol novolac resins, dicyclopentadiene type phenol resins, trishydroxyphenylmethane type novolac resins, aromatic modified phenol novolak resins, and the like are preferable from the viewpoint of availability.

In the case of novolak-type phenolic resins, phenols include phenol, cresol, xylenol, butylphenol, amylphenol, nonylphenol, butylmethylphenol, trimethylphenol, phenylphenol, etc. Naphthols include 1-naphthol, 2- Naphthol and the like are included, and in addition, the above bisphenols are included. Aldehydes include formaldehyde, acetaldehyde, propylaldehyde, butyraldehyde, valeraldehyde, capronaldehyde, benzaldehyde, chloraldehyde, bromaldehyde, glyoxal, malonaldehyde, succinaldehyde, glutaraldehyde, adipaldehyde, pimelinaldehyde, and sebacaldehyde. , acrolein, crotonaldehyde, salicylaldehyde, phthalaldehyde, hydroxybenzaldehyde and the like. Biphenyl-based cross-linking agents include bis(methylol)biphenyl, bis(methoxymethyl)biphenyl, bis(ethoxymethyl)biphenyl, bis(chloromethyl)biphenyl and the like.

Specific examples of acid anhydride curing agents include methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, pyromellitic anhydride, phthalic anhydride, trimellitic anhydride, and methylnadic acid.

Specific examples of amine curing agents include diethylenetriamine, triethylenetetramine, metaxylenediamine, isophoronediamine, diaminodiphenylmethane, diaminodiphenylsulfone, diaminodiphenyl ether, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl ) Amine compounds such as polyamidoamine, which are condensates of acids such as phenol, dicyandiamide, dimer acid, and polyamines.

Specific examples of other curing agents include phosphine compounds such as triphenylphosphine, phosphonium salts such as tetraphenylphosphonium bromide, 2-methylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole, 2 -imidazoles such as undecylimidazole and 1-cyanoethyl-2-methylimidazole, imidazole salts that are salts of imidazoles with trimellitic acid, isocyanuric acid or boric acid, quaternary ammonium salts such as trimethylammonium chloride, diazabicyclo compounds, salts of diazabicyclo compounds with phenols or phenol novolak resins, etc., complex compounds of boron trifluoride with amines, ether compounds, etc., aromatic phosphonium salts, or iodonium salts.

A curing accelerator can be used in the epoxy resin composition as needed. Examples of curing accelerators that can be used include imidazoles such as 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-(dimethylaminomethyl)phenol, 1,8-diaza-bicyclo(5 ,4,0) tertiary amines such as undecene-7, phosphines such as triphenylphosphine, tricyclohexylphosphine, triphenylphosphine and triphenylborane, and metal compounds such as tin octylate. 0.02 to 5 parts by mass of the curing accelerator is used as necessary with respect to 100 parts by mass of the epoxy resin component in the epoxy resin composition of the present invention. By using a curing accelerator, the curing temperature can be lowered and the curing time can be shortened.

An organic solvent or reactive diluent can be used in the epoxy resin composition for viscosity adjustment.

Examples of organic solvents include amides such as N,N-dimethylformamide and N,N-dimethylacetamide, and ethers such as ethylene glycol monomethyl ether, dimethoxydiethylene glycol, ethylene glycol diethyl ether, diethylene glycol diethyl ether, and triethylene glycol dimethyl ether. and ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methanol, ethanol, 1-methoxy-2-propanol, 2-ethyl-1-hexanol, benzyl alcohol, ethylene glycol, propylene glycol, butyl diglycol , alcohols such as pine oil, acetic acid esters such as butyl acetate, methoxybutyl acetate, methyl cellosolve acetate, cellosolve acetate, ethyl diglycol acetate, propylene glycol monomethyl ether acetate, carbitol acetate, benzyl alcohol acetate, and benzoic acid Benzoic acid esters such as methyl and ethyl benzoate, cellosolves such as methyl cellosolve, cellosolve, and butyl cellosolve, carbitols such as methyl carbitol, carbitol, and butyl carbitol, and fragrances such as benzene, toluene, and xylene Group hydrocarbons, dimethylsulfoxide, acetonitrile, N-methylpyrrolidone, etc., but are not limited to these.

Examples of reactive diluents include monofunctional glycidyl ethers such as allyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, tolyl glycidyl ether, resorcinol diglycidyl ether, and neopentyl glycol diglycidyl ether. , 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, propylene glycol diglycidyl ether and other bifunctional glycidyl ethers, glycerol polyglycidyl ether, trimethylolpropane Polyfunctional glycidyl ethers such as polyglycidyl ether, trimethylolethane polyglycidyl ether, and pentaerythritol polyglycidyl ether; glycidyl esters such as neodecanoic acid glycidyl ester; and glycidylamines such as phenyldiglycidylamine and tolyldiglycidylamine. include, but are not limited to.

These organic solvents or reactive diluents are preferably used singly or as a mixture of a plurality of them at a non-volatile content of 90% by mass or less, and the appropriate type and amount to be used are appropriately selected depending on the application. For printed wiring board applications, a polar solvent having a boiling point of 160° C. or lower, such as methyl ethyl ketone, acetone, or 1-methoxy-2-propanol, is preferred, and the amount used is preferably 40 to 80% by mass in terms of non-volatile matter. Further, when used for an adhesive film laminated on a copper foil, for example, ketones, acetic esters, carbitols, aromatic hydrocarbons, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc. can be used. The amount used is preferably 30 to 60% by mass in terms of non-volatile matter.

The epoxy resin composition may contain other thermosetting resins and thermoplastic resins as long as the properties are not impaired. For example, phenol resin, acrylic resin, petroleum resin, indene resin, coumarone-indene resin, phenoxy resin, polyurethane resin, polyester resin, polyamide resin, polyimide resin, polyamideimide resin, polyetherimide resin, polyphenylene ether resin, modified polyphenylene ether Resins, polyether sulfone resins, polysulfone resins, polyether ether ketone resins, polyphenylene sulfide resins, polyvinyl formal resins, etc., but not limited to these.

Various known flame retardants can be used in the epoxy resin composition for the purpose of improving the flame retardancy of the resulting cured product. Usable flame retardants include, for example, halogen flame retardants, phosphorus flame retardants, nitrogen flame retardants, silicone flame retardants, inorganic flame retardants, and organic metal salt flame retardants. From an environmental point of view, halogen-free flame retardants are preferred, and phosphorus-based flame retardants are particularly preferred. These flame retardants may be used alone or in combination of two or more.

Both inorganic phosphorus compounds and organic phosphorus compounds can be used as phosphorus flame retardants. Examples of inorganic phosphorus compounds include red phosphorus, monoammonium phosphate, diammonium phosphate, triammonium phosphate, ammonium phosphates such as ammonium polyphosphate, and inorganic nitrogen-containing phosphorus compounds such as amide phosphoric acid. be done. Examples of organic phosphorus compounds include aliphatic phosphates, phosphate ester compounds, condensed phosphates such as PX-200 (manufactured by Daihachi Chemical Industry Co., Ltd.), phosphonic acid compounds, phosphinic acid compounds, General-purpose organic phosphorus compounds such as phosphine oxide compounds, phosphorane compounds, organic nitrogen-containing phosphorus compounds such as phosphazene, metal salts of phosphinic acid, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10 -oxide, 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(2,7-dihydroxynaphthyl)-10H-9-oxa-10 Examples include cyclic organic phosphorus compounds such as -phosphaphenanthrene-10-oxide, and phosphorus-containing epoxy resins and phosphorus-containing curing agents which are derivatives obtained by reacting these compounds with compounds such as epoxy resins and phenol resins.

The blending amount of the flame retardant is appropriately selected according to the type of phosphorus-based flame retardant, the components of the epoxy resin composition, and the desired degree of flame retardancy. For example, the phosphorus content in the organic components (excluding the organic solvent) in the epoxy resin composition is preferably 0.2 to 4% by mass, more preferably 0.4 to 3.5% by mass, More preferably, it is 0.6 to 3% by mass. If the phosphorus content is too low, it may become difficult to ensure flame retardancy, and if it is too high, the heat resistance may be adversely affected. Moreover, when using a phosphorus flame retardant, you may use flame retardant adjuvant, such as magnesium hydroxide, together.

A filler can be used in the epoxy resin composition as needed. Specifically, fused silica, crystalline silica, alumina, silicon nitride, aluminum hydroxide, boehmite, magnesium hydroxide, talc, mica, calcium carbonate, calcium silicate, calcium hydroxide, magnesium carbonate, barium carbonate, barium sulfate, Boron nitride, carbon, carbon fiber, glass fiber, alumina fiber, silica alumina fiber, silicon carbide fiber, polyester fiber, cellulose fiber, aramid fiber, ceramic fiber, fine particle rubber, thermoplastic elastomer, pigment and the like. The reason for using a filler in general is the effect of improving the impact resistance. Moreover, when metal hydroxides such as aluminum hydroxide, boehmite, and magnesium hydroxide are used, they act as flame retardant aids and have the effect of improving flame retardancy. The blending amount of these fillers is preferably 1 to 150% by mass, more preferably 10 to 70% by mass, based on the entire epoxy resin composition. If the blending amount is too large, there is a risk that the adhesiveness required for laminated circuit board applications will decrease, and furthermore, the cured product will be brittle, and there is a risk that sufficient mechanical properties will not be obtained. On the other hand, if the blending amount is too small, there is a fear that the blending effect of the filler, such as improving the impact resistance of the cured product, may not be achieved.

When the epoxy resin composition is used as a plate-like substrate or the like, fibrous fillers are preferred in terms of dimensional stability, bending strength, and the like. A more preferred substrate is a glass fiber substrate in which glass fibers are woven into a mesh.

The epoxy resin composition further contains nuclide additives such as silane coupling agents, antioxidants, release agents, antifoaming agents, emulsifiers, thixotropic agents, smoothing agents, flame retardants, pigments, etc. be able to. These additives are preferably in the range of 0.01 to 20 mass % with respect to the epoxy resin composition.

A fibrous base material can be impregnated with the epoxy resin composition to prepare a prepreg used in a printed wiring board. As the fibrous base material, inorganic fibers such as glass, and woven or non-woven fabrics of organic fibers such as polyester resin, polyamine resin, polyacrylic resin, polyimide resin, aromatic polyamide resin, etc. can be used, but not limited thereto. not something. The method for producing a prepreg from an epoxy resin composition is not particularly limited. It is obtained by semi-curing (B-staged) the components, and can be dried by heating at 100 to 200° C. for 1 to 40 minutes, for example. Here, the resin content in the prepreg is preferably 30 to 80% by mass.

In order to cure the prepreg, a laminate curing method generally used for manufacturing printed wiring boards can be used, but the method is not limited to this. For example, when forming a laminate using prepreg, one or more prepregs are laminated, a metal foil is arranged on one side or both sides to form a laminate, and this laminate is heated and pressed to form an integrated laminate. become Here, as the metal foil, copper, aluminum, brass, nickel, or the like can be used alone, as an alloy, or as a composite metal foil. Then, the prepared laminate is pressurized and heated to cure the prepreg and obtain a laminate. At that time, it is preferable to set the heating temperature to 160 to 220° C., the pressure to 50 to 500 N/cm ² , and the time to heat and press for 40 to 240 minutes to obtain the desired cured product. If the heating temperature is too low, the curing reaction will not proceed sufficiently, and if the heating temperature is too high, the epoxy resin composition may begin to decompose. In addition, if the pressure is too low, air bubbles may remain inside the resulting laminate, resulting in deterioration of the electrical properties. There is a risk that it will not be possible. Furthermore, if the heating and pressurizing time is short, the curing reaction may not proceed sufficiently, and if it is long, the epoxy resin composition in the prepreg may be thermally decomposed, which is not preferable.

The epoxy resin composition can be cured in the same manner as for known epoxy resin compositions to obtain a cured epoxy resin. As a method for obtaining a cured product, the same methods as those for known epoxy resin compositions can be used, such as casting, injection, potting, dipping, drip coating, transfer molding, compression molding, resin sheets, resins, etc. A method of forming a laminated plate by laminating a laminated copper foil, prepreg, or the like and curing under heat and pressure is preferably used. The curing temperature at that time is usually in the range of 100 to 300° C., and the curing time is usually about 1 to 5 hours.

We prepared an epoxy resin composition and evaluated the epoxy resin cured product of the laminate by heat curing. An excellent epoxy resin composition was able to be provided.

EXAMPLES The present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to these. Unless otherwise specified, "parts" represent parts by mass, and "%" represents mass%. Moreover, the measurement method was each measured by the following methods.

Epoxy equivalent: Measured in accordance with JIS K7236, and expressed in units of "g/eq." Specifically, using an automatic potentiometric titrator (manufactured by Hiranuma Sangyo Co., Ltd., COM-1600ST), using chloroform as a solvent, adding tetraethylammonium bromide acetic acid solution, 0.1 mol / L perchloric acid - acetic acid solution was titrated with

Softening point: Measured according to JIS K7234 standard, ring and ball method. Specifically, an automatic softening point apparatus (ASP-MG4 manufactured by Meitec Co., Ltd.) was used.

Phenol hydroxyl group equivalent: Measured according to JIS K0070 standard, and expressed in units of "g/eq."

Glass transition temperature: IPC-TM-650 2.4.25. DSC Tgm (for the tangential line of the glass state and the rubber state was expressed as the temperature at the middle temperature of the mutation curve).

Copper foil peel strength and interlayer adhesion: Measured according to JIS C6481, and the interlayer adhesion was measured by peeling off between the 7th and 8th layers.

Relative permittivity and dielectric loss tangent: According to IPC-TM-650 2.5.5.9, using a material analyzer (manufactured by AGILENT Technologies), evaluate by determining the relative permittivity and dielectric loss tangent at a frequency of 1 GHz by the capacitance method. did.

Flame retardancy: Evaluated by vertical method according to UL94. The evaluation was described as V-0, V-1 and V-2.

[Epoxy resin]
A1: 2,6-xylenol/dicyclopentadiene type epoxy resin obtained in Synthesis Example 2 A2: 2,6-xylenol/dicyclopentadiene type epoxy resin obtained in Synthesis Example 3 A3: Phenol/dicyclopentadiene type Epoxy resin (manufactured by DIC Corporation, HP-7200H, epoxy equivalent 280, softening point 83 ° C.)
A4: Aromatic modified novolac epoxy resin (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., YDAN-1000-9HH, epoxy equivalent 293, softening point 97 ° C.)
A5: Phosphorus-containing epoxy resin (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., YDFR-1320, epoxy equivalent 747, phosphorus content 5.0%)

[Curing agent]
B1: Phenol novolac resin (manufactured by Aica Kogyo Co., Ltd., Shaunol BRG-557, phenol hydroxyl equivalent 105, softening point 80 ° C.)
B2: Dicyclopentadiene type phenol resin (manufactured by Gun Ei Chemical Industry Co., Ltd., GDP-6140, phenol hydroxyl equivalent 196, softening point 130 ° C.)
B3: Aromatic modified phenolic resin obtained in Synthesis Example 4 B4: Trishydroxyphenylmethane type novolac resin (manufactured by Gunei Chemical Industry Co., Ltd., Resitop TPM-100, phenol hydroxyl equivalent 98, softening point 108°C)
B5: Dicyandiamide (manufactured by Nippon Carbide Industry Co., Ltd., DIHARD, active hydrogen equivalent 21)

[Curing accelerator]
2E4MZ: 2-ethyl-4-methylimidazole (manufactured by Shikoku Kasei Co., Ltd., Curesol)

Synthesis example 1
1220 parts of 2,6-xylenol and 14.2 parts of 47% BF ₃ ether complex were charged into a separable glass flask equipped with a stirrer, thermometer, nitrogen gas introduction device, condenser tube and dropping device, and stirred. Warmed to 115°C. While maintaining the same temperature, 132 parts of dicyclopentadiene was added dropwise over 4 hours. After reacting at a temperature of 120 to 130° C. for 3 hours, 2.0 parts of calcium hydroxide was added. An additional 4.0 parts of 10% aqueous oxalic acid solution was added. Then, after heating to 160° C. for dehydration, the mixture was heated to 200° C. under a reduced pressure of 5 mmHg to evaporate and remove unreacted 2,6-xylenol. 900 parts of methyl isobutyl ketone (MIBK) was added to dissolve the product, and 300 parts of hot water at 80° C. was added to wash with water to separate and remove the water in the lower layer. After that, the mixture was heated to 200° C. under a reduced pressure of 5 mmHg to remove MIBK by evaporation to obtain 355 parts of a reddish brown diphenol compound.

Synthesis example 2
184 parts of the diphenol compound obtained in Synthesis Example 1, 370 parts of epichlorohydrin and 74 parts of diethylene glycol dimethyl ether were added and heated to 60°C. Under a reduced pressure of 110 mmHg, while maintaining the temperature at 58 to 62° C., 80 parts of a 49% sodium hydroxide aqueous solution was added dropwise over 4 hours. During this time, epichlorohydrin was azeotropically distilled with water, and the distilled water was sequentially removed out of the system. After completion of the reaction, epichlorohydrin was recovered at 5 mmHg and 180° C., and 560 parts of MIBK was added to dissolve the product. After that, 33 parts of a 10% aqueous sodium hydroxide solution is added, reacted at 80 to 90° C. for 2 hours, 230 parts of water is added to dissolve the by-produced salt, and the solution is left to stand to separate and remove the lower salt solution. did. After neutralization with an aqueous solution of phosphoric acid, the resin solution was washed with water until the washings became neutral and filtered. MIBK was distilled off by heating to 180° C. under a reduced pressure of 5 mmHg to obtain 238 parts of a reddish brown 2,6-xylenol/dicyclopentadiene type epoxy resin. The epoxy equivalent was 271 and the softening point was 55°C.

Synthesis example 3
184 parts of the diphenol compound obtained in Synthesis Example 1, 320 parts of epichlorohydrin and 64 parts of diethylene glycol dimethyl ether were added and heated to 60°C. Under a reduced pressure of 110 mmHg, while maintaining the temperature at 58 to 62° C., 80 parts of a 49% sodium hydroxide aqueous solution was added dropwise over 4 hours. During this time, epichlorohydrin was azeotropically distilled with water, and the distilled water was sequentially removed out of the system. After completion of the reaction, epichlorohydrin was recovered at 5 mmHg and 180° C., and 560 parts of MIBK was added to dissolve the product. After that, 33 parts of a 10% aqueous sodium hydroxide solution is added, reacted at 80 to 90° C. for 2 hours, 230 parts of water is added to dissolve the by-produced salt, and the solution is left to stand to separate and remove the lower salt solution. did. After neutralization with an aqueous solution of phosphoric acid, the resin solution was washed with water until the washings became neutral and filtered. MIBK was distilled off by heating to 180° C. under a reduced pressure of 5 mmHg to obtain 230 parts of a reddish brown 2,6-xylenol/dicyclopentadiene type epoxy resin. The epoxy equivalent was 310 and the softening point was 70°C.

Synthesis example 4
105 parts of phenol novolac resin (phenolic hydroxyl equivalent 105, softening point 130 ° C.), p-toluenesulfonic acid, and p-toluenesulfonic acid was charged, and the temperature was raised to 150°C. While maintaining the same temperature, 94 parts of styrene was added dropwise over 3 hours, and stirring was continued at the same temperature for 1 hour. Then, it was dissolved in 500 parts of MIBK and washed with water at 80° C. five times. Subsequently, MIBK was distilled off under reduced pressure to obtain an aromatic modified phenol novolac resin. The phenolic hydroxyl equivalent was 199 and the softening point was 110°C.

Example 1
100 parts of epoxy resin (A1), 40 parts of curing agent (B1), 0.2 parts of 2E4MZ as a curing accelerator, mixed solvent prepared with methyl ethyl ketone, propylene glycol monomethyl ether, and N,N-dimethylformamide. to obtain an epoxy resin composition varnish. A glass cloth (WEA 7628 XS13, manufactured by Nitto Boseki Co., Ltd., 0.18 mm thick) was impregnated with the obtained epoxy resin composition varnish. The impregnated glass cloth was dried in a hot air circulating oven at 150° C. for 9 minutes to obtain a prepreg. The obtained 8 sheets of prepreg and copper foil (manufactured by Mitsui Kinzoku Mining Co., Ltd., 3EC-III, thickness 35 μm) are stacked on top and bottom, and vacuum pressed at 2 MPa under temperature conditions of 130 ° C. x 15 minutes + 190 ° C. x 80 minutes. , a laminate having a thickness of 1.6 mm was obtained. Table 1 shows the results of copper foil peel strength, interlayer adhesive strength, and glass transition temperature of the laminate.

In addition, the obtained prepreg was loosened and passed through a sieve to obtain powdery prepreg powder of 100 mesh pass. The obtained prepreg powder was placed in a fluororesin mold and vacuum pressed at 2 MPa under temperature conditions of 130° C.×15 minutes+190° C.×80 minutes to obtain a test piece of 50 mm square×2 mm thickness. Table 1 shows the relative permittivity and dielectric loss tangent results of the test piece.

Examples 2-8
They were blended in the amounts (parts) shown in Table 1, and the same operation as in Example 1 was performed to obtain a laminate and a test piece. The amount of curing accelerator used was such that the varnish gel time could be adjusted to about 300 seconds. The same test as in Example 1 was conducted, and the results are shown in Table 1.

Comparative Examples 1-8
They were blended in the amounts (parts) shown in Table 2, and the same operation as in Example 1 was performed to obtain a laminate and a test piece. The same test as in Example 2 was conducted and the results are shown in Table 2.

Comparative example 9
100 parts of epoxy resin (A3) and 3.8 parts of curing agent (B5) were blended without using 2E4MZ, and the same operation as in Example 1 was performed to obtain a prepreg. When the obtained prepreg was observed, crystals thought to be the curing agent (B5) were scattered on the prepreg. Therefore, it was evaluated as NG, and no laminate was produced.

The examples have significantly reduced dielectric properties while maintaining Tg and adhesion.

Example 9 and Comparative Example 10
They were blended in the amounts (parts) shown in Table 3, and the same operation as in Example 1 was performed to obtain a laminate and a test piece. The same test as in Example 1 was conducted, and the results are shown in Table 3.

As is clear from these results, the examples using the 2,6-disubstituted dicyclopentadiene type epoxy resin composition of the present invention exhibited very good low dielectric properties as a circuit board (laminate). and excellent adhesion.

Claims (6)

Epoxy containing 10 to 100% by mass of a 2,6-disubstituted phenol/dicyclopentadiene type epoxy resin having an epoxy equivalent (g/eq.) of more than 270 and not more than 2000, represented by the following general formula (1) An epoxy resin composition for circuit boards comprising a resin component and a curing agent as essential components.

(In the formula, R represents an alkyl group having 1 to 8 carbon atoms, a phenyl group or an allyl group, and n represents an average number of 0.05 to 5. ) 2. The epoxy resin composition for a circuit board according to claim 1, wherein the active hydrogen group of the curing agent is blended in the range of 0.2 mol or more and 1.5 mol or less per 1 mol of the epoxy groups of all the epoxy resin components . 3. The epoxy resin composition for circuit boards according to claim 1, wherein the curing agent is a phenolic resin curing agent. A prepreg for a circuit board, wherein the epoxy resin composition according to any one of claims 1 to 3 is used. A laminate for a circuit board, wherein the epoxy resin composition according to any one of claims 1 to 3 is used. A printed wiring board obtained by using the epoxy resin composition according to any one of claims 1 to 3.