JP7211744B2 - Epoxy resin composition and cured product thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to an epoxy resin composition used for manufacturing a printed wiring board or multilayer printed wiring board having high heat resistance and excellent flame retardancy, and a prepreg, laminate, or printed wiring board obtained from the epoxy resin composition. .

Epoxy resin compositions are excellent in adhesiveness, flexibility, heat resistance, chemical resistance, insulation, and curing reactivity, so they are used in a wide range of applications such as paints, civil engineering adhesion, cast molding, electrical and electronic materials, and film materials. there is In particular, it is widely practiced to impart flame retardancy to epoxy resin compositions for use in printed wiring boards, which is one of electrical and electronic materials.

In recent years, electronic devices have been made flame-retardant, and in consideration of the impact on the environment, efforts have been made to suppress toxic gases generated during combustion. It is a halogen-free flame retardant that aims at flame retardancy with an organic phosphorus compound instead of flame retardancy with a halogen-containing compound as typified by a conventional brominated epoxy resin. These countermeasures are widely used and recognized as phosphorus flame retardancy not only for electronic circuit boards but also in the general field of epoxy resins for circuit boards.

As specific typical examples of such flame-retardant epoxy resins, proposals have been made to apply organophosphorus compounds as disclosed in Patent Documents 1 to 4. Patent Document 1 discloses a thermosetting resin obtained by reacting 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide with epoxy resins at a predetermined molar ratio.

In Patent Documents 1 and 2, a phosphorus compound that exhibits flame retardancy and a polyfunctional epoxy resin are reacted, so the heat resistance after curing using a curing agent is the glass transition temperature (Tg) equivalent to that of an FR-4 substrate. However, in recent years, as substrates have become more densely mounted and mounting from automobile cabins to around the hood drive part has progressed, Tg, which is equivalent to FR-5 heat resistance, is required to cope with even higher temperatures. The reality is that there are

Patent Document 3 describes a specific example of synthesizing a phosphorous-containing epoxy resin in combination with a trifunctional epoxy resin that provides a higher Tg than conventional novolak type epoxy resins, and giving a cured product with a Tg of about 180°C. ing. Further, Patent Document 4 describes a highly heat-resistant phosphorus-containing epoxy resin obtained by reacting a phosphorus-containing oligomer obtained by reacting a phosphorus compound and hydroxybenzaldehyde with a polyfunctional epoxy resin. Specific examples are disclosed. A large number of techniques have been published and are becoming generalized as substrates having a heat resistance standard equivalent to FR-5 such as these.

In any of these documents, a high phosphorus content is required to ensure flame retardancy, and there has been a demand for the establishment of a method for exhibiting high flame retardancy even with a low phosphorus content.

JP-A-11-166035 JP-A-11-279258 Japanese Patent Application Laid-Open No. 2002-206019 JP 2013-35921 A

The problem to be solved by the present invention is an epoxy resin composition that exhibits excellent heat resistance and flame retardancy in a cured product even with a low phosphorus content, and that provides excellent cured product properties particularly for use in printed wiring boards. It is about providing things.

In order to solve the above-mentioned problems, the present inventors have made intensive studies on epoxy resins. The inventors have found that the heat resistance and flame retardancy of the cured product are excellent even when the phosphorus content is low, and have completed the present invention.

ここで、ｎは繰り返し数であって０以上の数を示し、その平均値は１．３～２０の数であり、Ｒ^１、Ｒ^２およびＲ^３はそれぞれ独立に水素原子または炭素数１～８の炭化水素基を表す。 That is, the present invention is an epoxy resin composition comprising an epoxy resin and a curing agent as essential components, wherein the epoxy resin comprises a biphenyl aralkyl type epoxy resin represented by the following general formula (1) and a phosphorus-containing epoxy resin. An epoxy resin composition characterized by

Here, n is the number of repetitions and represents a number of 0 or more, its average value is a number of 1.3 to 20, R ¹ , R ² and R ³ are each independently a hydrogen atom or a represents the hydrocarbon group of 8.

The epoxy equivalent of the phosphorus-containing epoxy resin is 200 to 1000 g/eq. is preferable, and the phosphorus content is preferably 1.0 to 6.0% by mass.

The present invention also provides a prepreg, laminate, or printed wiring board using the epoxy resin composition.

INDUSTRIAL APPLICABILITY The epoxy resin composition of the present invention exhibits excellent heat resistance and flame retardancy in its cured product even with a low phosphorus content, and is therefore useful for printed wiring board applications, particularly for automotive applications where high reliability is required. Useful for substrates.

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 comprises an epoxy resin (A) and a curing agent (B) as essential components, wherein the epoxy resin (A) is a biphenyl aralkyl epoxy resin (a1) represented by the above general formula (1); An epoxy resin composition characterized by containing a phosphorus-containing epoxy resin (a2) as an essential component.

The epoxy resin (A) contains the biphenyl aralkyl type epoxy resin (a1) and the phosphorus-containing epoxy resin (a2) as essential components, and may contain other various epoxy resins (a3). In order to develop heat resistance and flame retardancy at a low phosphorus content, the biphenyl aralkyl type epoxy resin (a1) is preferably 5% by mass or more and 30% by mass or less, preferably 7% by mass or more, of the total epoxy resin (A). 25% by mass or less is more preferable.

In general formula (1) above, R ¹ , R ² and R ³ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. Examples of hydrocarbon groups having 1 to 8 carbon atoms include alkyl groups having 1 to 8 carbon atoms such as methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, t-butyl group and hexyl group, Cycloalkyl groups having 5 to 8 carbon atoms such as cyclohexyl groups; aryl groups having 6 to 8 carbon atoms such as phenyl groups, tolyl groups and xylyl groups; and carbon numbers such as benzyl groups, phenethyl groups and 1-phenylethyl groups. Examples include, but are not limited to, 7 to 8 aralkyl groups, each of which may be the same or different. Preferred R ¹ , R ² , and R ³ are a hydrogen atom, a 1-phenylethyl group, or a methyl group from the viewpoint of availability and physical properties such as heat resistance when cured.

n is the number of repetitions and represents a number of 0 or more, the average value (number average) is 1.3 to 20, preferably 1.5 to 15, more preferably 1.7 to 10, 2 to 6 is more preferred.

Further, the weight average molecular weight (Mw) of the biphenyl aralkyl epoxy resin (a1) measured by gel permeation chromatography (GPC) is preferably 1000 to 8000, more preferably 2000 to 7000, even more preferably 3000 to 6000.

The content of the n=0 component, where n is 0, is preferably less than 15%, more preferably 10% or less, and even more preferably 6% or less as area % by GPC measurement from the viewpoint of solvent solubility. In particular, in the case of dissolving in an organic solvent for use in laminates or the like, the content is preferably 2 to 5%. In addition, the content of n=5 or more components is preferably 20% or more, more preferably 25% or more, and even more preferably 27% or more, from the viewpoint of improving heat resistance. GPC measurement conditions are according to the method described in Examples.

The epoxy equivalent (g/eq.) of the biphenylaralkyl-type epoxy resin (a1) is preferably 200-240, more preferably 205-235, and even more preferably 210-230. The softening point is preferably 70 to 130°C, more preferably 80 to 120°C, even more preferably 90 to 110°C.

The biphenyl aralkyl type epoxy resin (a1) can be produced by the method disclosed in WO2011/074517 and the like. Specifically, it is a method of reacting a biphenol compound and a biphenyl-based condensing agent with less than 1 mol of the biphenyl-based condensing agent per 1 mol of the biphenol compound, and epoxidizing the resulting biphenylaralkyl-type phenolic resin.

Examples of the biphenol compound include 4,4'-biphenol, 2,4'-biphenol, and 2,2'-biphenol, with 4,4'-biphenol being preferred from the viewpoint of reactivity. Further, these biphenol compounds may have one hydrocarbon group having 1 to 8 carbon atoms as a substituent on each aromatic ring.

Examples of the biphenyl-based condensing agent include biphenyl-4,4′-dimethanol, 4,4′-bis(chloromethyl)biphenyl, 4,4′-bis(bromomethyl)biphenyl, 4,4′-bis(methoxymethyl) ) biphenyl, 4,4′-bis(ethoxymethyl)biphenyl, biphenyl-2,4′-dimethanol, 2,4′-bis(chloromethyl)biphenyl, 2,4′-bis(bromomethyl)biphenyl, 2, 4'-bis(methoxymethyl)biphenyl, 2,4'-bis(ethoxymethyl)biphenyl, biphenyl-2,2'-dimethanol, 2,2'-bis(chloromethyl)biphenyl, 2,2'-bis (bromomethyl)biphenyl, 2,2'-bis(methoxymethyl)biphenyl, 2,2'-bis(ethoxymethyl)biphenyl and the like. From the viewpoint of reactivity, biphenyl-4,4'-dimethanol and 4,4'-bis(chloromethyl)biphenyl are preferred, and from the viewpoint of reducing ionic impurities, biphenyl-4,4'-dimethanol , 4,4′-bis(methoxymethyl)biphenyl are preferred. Further, these biphenyl-based condensing agents may have one or two hydrocarbon groups having 1 to 8 carbon atoms as substituents on each aromatic ring.

For the reaction between the biphenol compound and the biphenyl-based condensing agent, an excess amount of the biphenol compound is used relative to the biphenyl-based condensing agent. The amount of the biphenyl condensing agent used is preferably 0.1 to 0.55 mol, more preferably 0.3 to 0.5 mol, per 1 mol of the biphenol compound. If the amount of biphenyl-based condensing agent used is too large, the amount of unreacted raw material biphenol compound decreases, but the molecular weight itself increases, and the softening point and melt viscosity of the resin increase, which may interfere with moldability and workability. . On the other hand, if it is too small, the amount of unreacted raw material biphenol compound removed after the reaction is finished becomes large, which is not industrially preferable.

This reaction is usually carried out in the presence of an acid catalyst such as a known inorganic acid or organic acid. Examples of such acid catalysts include mineral acids such as hydrochloric acid, sulfuric acid and phosphoric acid; organic acids such as formic acid, oxalic acid, trifluoroacetic acid and p-toluenesulfonic acid; zinc chloride, aluminum chloride, iron chloride; Examples include Lewis acids such as boron trifluoride, solid acids such as activated clay, silica-alumina, and zeolite.

The reaction is usually carried out at 10-250° C. for 1-20 hours. Furthermore, as solvents for the reaction, for example, alcohols such as methanol, ethanol, propanol, butanol, ethylene glycol, methyl cellosolve, and ethyl cellosolve; ethers such as diethylene glycol dimethyl ether and triglyme; and halogens such as chlorobenzene and dichlorobenzene. It is preferable to use an aromatic compound or the like, and among these, ethyl cellosolve, diethylene glycol dimethyl ether, triglyme and the like are particularly preferable.

Since the biphenyl aralkyl-type phenolic resin obtained by the above method may contain a large amount of unreacted starting biphenol compound, it is preferable to add a step of removing the unreacted starting biphenol compound as necessary after the completion of the reaction. From the viewpoint of solvent solubility, the content of the unreacted starting biphenol compound is preferably less than 15% (area % by GPC measurement), more preferably 10% or less, even more preferably 6% or less, and particularly 3 to 5%. preferable.

In the process of removing unreacted raw biphenol compounds of biphenylaralkyl-type phenolic resins, for example, a mixed solvent of a poor solvent and a good solvent is used in order to dissolve the high-molecular-weight components produced without dissolving the raw biphenol compounds. Then, it is preferable to remove the unreacted starting biphenol compound by a method such as filtration. The poor solvent is not particularly limited as long as it hardly dissolves the starting biphenol compound, and examples thereof include aromatic solvents such as benzene, toluene and xylene. Good solvents include alcohols, ethers, halogenated aromatic compounds, and ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone.

The softening point of the biphenylaralkyl-type phenolic resin can be easily adjusted by changing the molar ratio of the biphenol compound and the biphenyl condensing agent. If the ratio is changed, the content of the unreacted starting biphenol compound that needs to be removed increases, the workability deteriorates, and the yield greatly decreases, so there is a limit.

The biphenylaralkyl type epoxy resin (a1) used in the present invention can be produced by reacting the above biphenylaralkyl type phenolic resin with epichlorohydrin. This reaction can be carried out in the same manner as a normal epoxidation reaction. For example, after dissolving a biphenylaralkyl-type phenolic resin in an excess of epichlorohydrin, the solution is dissolved in the presence of an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide at 50 to 150°C, preferably at 60 to 120°C for 1 to 10 hours. A method of reacting can be mentioned. At this time, the amount of alkali metal hydroxide used is 0.8 to 1.2 mol, preferably 0.9 to 1.0 mol, per 1 mol of hydroxyl group in the biphenylaralkyl-type phenolic resin. Epichlorohydrin is used in an excess amount relative to the hydroxyl groups in the biphenylaralkyl-type phenolic resin, and is usually 1.5 to 15 mol, preferably 2 to 8 mol, per 1 mol of the hydroxyl groups in the biphenylaralkyl-type phenolic resin. . After completion of the reaction, excess epichlorohydrin is distilled off, the residue is dissolved in a solvent such as toluene or methyl isobutyl ketone, filtered and washed with water to remove inorganic salts, and then the solvent is distilled off to obtain biphenyl aralkyl. type epoxy resin can be obtained. During epoxidation, the epoxy groups of the resulting epoxy compound may be ring-opened and condensed to form a small amount of an oligomerized epoxy compound as a by-product.

The phosphorus-containing epoxy resin (a2) used in the present invention is preferably used alone or in combination of two or more. A phosphorus-free epoxy resin (a3) may also be used in combination. As the phosphorus-containing epoxy resin (a2), as disclosed in JP-A-04-11662, JP-A-05-214070, JP-A-2000-309624, JP-A-2002-265562, etc. , Reactive phosphorus compounds such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and diphenylphosphine oxide, and optionally 1,4-benzoquinone and 1,4-naphthoquinone. Particularly preferred is one obtained by reacting with an epoxy resin after reacting with a quinone compound.

The epoxy equivalent (g/eq.) of these phosphorus-containing epoxy resins (a2) is preferably 200-1000, more preferably 250-800, and even more preferably 270-700. The phosphorus content is preferably 1.0 to 6.0% by mass, more preferably 1.5 to 5.5% by mass, even more preferably 1.7 to 5.0% by mass.

When the phosphorus-free epoxy resin (a3) is used together, the phosphorus content of the phosphorus-containing epoxy resin (a23) obtained by mixing the phosphorus-containing epoxy resin (a2) and the phosphorus-free epoxy resin (a3) is The phosphorus content of the phosphorus-containing epoxy resin (a2) and the mixing amount of the phosphorus-containing epoxy resin (a2) and the phosphorus-free epoxy resin (a3) are adjusted so that the phosphorus content of the resin (a2) falls within the preferred range. do.

The phosphorus content in the epoxy resin composition to achieve V-0 in the flame retardancy test UL-94 is preferably 1.0 to 5.0% by mass, more preferably 1.3 to 4.5% by mass. preferable. 1.5 to 2.3% by weight is particularly preferred. If the phosphorus content in the epoxy resin composition is low, the flame retardance may be insufficient, and if it is high, the heat resistance and adhesion may be impaired.

Specific examples of the phosphorus-containing epoxy resin (a2) include Epotoot FX-305, Epotoot FX-289B, Epotoot FX-1225, YDFR-1320, and TX-1328 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.). but not limited to these.

The phosphorus-free epoxy resin (a3) that can be used in combination is not particularly limited, and ordinary epoxy resins having two or more epoxy groups in the molecule can be used, and trifunctional or higher epoxy resins are preferred. For example, 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, Resorcinol-type epoxy resins, biphenylaralkyl-type epoxy resins other than those represented by the general formula (1) above, naphthalenediol-type epoxy resins, phenol novolac-type epoxy resins, aromatic modified phenol novolak-type epoxy resins, cresol novolac-type epoxy resins , alkyl novolak type epoxy resin, bisphenol novolac 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 resins, aliphatic cyclic epoxy resins, diaminodiphenylmethane tetraglycidylamine, aminophenol-type epoxy resins, urethane-modified epoxy resins, oxazolidone ring-containing epoxy resins and the like may be mentioned, but are not limited to these. From the viewpoint of availability, naphthalenediol type epoxy resin, phenol novolac type epoxy resin, aromatic modified phenol novolac type epoxy resin, cresol novolak type epoxy resin, α-naphthol aralkyl type epoxy resin, dicyclopentadiene type epoxy resin, oxazolidone Ring-containing epoxy resins and the like are preferred.

The curing agent (B) in the epoxy resin composition of the present invention is not particularly limited, and conventionally known curing agents can be used. For example, commonly used curing agents such as phenolic resin curing agents, acid anhydride curing agents, amine curing agents, and other curing agents can be used. , may be used in combination of two or more.

In the epoxy resin composition of the present invention, the amount of the curing agent (B) used is 0.2 mol or more of the active hydrogen group of the curing agent (B) per 1 mol of the epoxy groups of the entire epoxy resin (A). 0.5 mol or less. 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), the above biphenol compounds, catechol, resorcinol, methylresorcinol, hydroquinone, monomethylhydroquinone, dimethylhydroquinone, trimethylhydroquinone , mono-t-butylhydroquinone, di-t-butylhydroquinone and other dihydroxybenzenes, dihydroxynaphthalene, dihydroxymethylnaphthalene, trihydroxynaphthalene and other hydroxynaphthalenes, and phosphorus such as LC-950PM60 (manufactured by Shin-AT&C). Containing phenol curing agent, phenol novolak resin such as Shaunol BRG-555 (manufactured by Aica Kogyo Co., Ltd.), cresol novolak resin such as DC-5 (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.), aromatic modified phenol novolac resin, bisphenol A Novolac resins, trishydroxyphenylmethane type novolac resins such as Resitop TPM-100 (manufactured by Gun Ei Chemical Industry Co., Ltd.), phenols such as naphthol novolac resins, 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, naphthols and/or condensates of bisphenols and xylylene glycol, phenols and/or naphthols and isopropenylacetophenone condensates, reaction products of phenols, naphthols and/or bisphenols with dicyclopentadiene, condensates of phenols, naphthols and/or bisphenols and biphenyl-based cross-linking agents, so-called "novolac-type phenol phenolic compounds called "resin". Phenol novolak resins, dicyclopentadiene type phenol resins, trishydroxyphenylmethane type novolak 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- Examples include naphthol, and other examples include the above-mentioned biphenol compounds and bisphenols. 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-un imidazoles such as decylimidazole and 1-cyanoethyl-2-methylimidazole; imidazole salts which 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 and phenols or phenolic novolak resins, complex compounds of boron trifluoride and amines or ether compounds, aromatic phosphonium salts, or iodonium salts can be mentioned.

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 example, for printed wiring board applications, a polar solvent having a boiling point of 160° C. or less, 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. In addition, for adhesive film applications, for example, it is preferable to use ketones, acetic esters, carbitols, aromatic hydrocarbons, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc., and the amount used is nonvolatile is preferably 30 to 60% by mass.

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 combination with the epoxy resin composition for the purpose of improving the flame retardancy of the resulting cured product. Flame retardants that can be used in combination include, for example, phosphorus-based flame retardants, nitrogen-based flame retardants, silicone-based flame retardants, and inorganic flame retardants. 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, Phosphine oxide compounds such as PPQ (manufactured by Hokko Chemical Industry Co., Ltd.), phosphorane compounds, general-purpose organic phosphorus compounds such as organic nitrogen-containing phosphorus compounds such as phosphazene, metal salts of phosphinic acid, 9,10-dihydro- 9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(2, Cyclic organic phosphorus compounds such as 7-dihydroxynaphthyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, phosphorus-containing curing agents which are derivatives obtained by reacting them with compounds such as phenol resins, etc. mentioned.

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. Even when a phosphorus-based flame retardant is blended, for example, the phosphorus content in the organic components (excluding the organic solvent) in the epoxy resin composition is the total of all phosphorus compounds (phosphorus-containing epoxy resin and phosphorus-based flame retardant) The amount is preferably 0.2% by mass or more and 4% by mass or less, more preferably 0.4% by mass or more and 3.5% by mass or less, and still more preferably 0.6% by mass or more and 3% by mass or less. be. If the phosphorus content is too low, it may become difficult to ensure flame retardancy, and if it is too high, heat resistance may be adversely affected, and the object of the present invention cannot be achieved. Moreover, you may use flame-retardant auxiliary agents, 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 parts by mass, more preferably 10 to 70 parts by mass, per 100 parts by mass of the epoxy resin composition. If the compounding amount is too large, there is a risk that the adhesiveness required for use as a laminated plate will be lowered, 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 parts by mass with respect to 100 parts by mass of the epoxy resin composition.

By impregnating a fibrous base material with the epoxy resin composition, a prepreg for use in printed wiring boards and the like can be produced. 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 heat-drying to semi-harden (to B-stage) the resin component. For example, it can be heat-dried at 100 to 200° C. for 1 to 40 minutes. Here, the amount of resin in the prepreg is preferably 30 to 80% by mass.

In order to cure the prepreg, a laminate curing method generally used in the manufacture of 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. Also, if the applied 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. 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. Moreover, a printed wiring board can be obtained by forming a circuit on the laminate by an additive method, a subtractive method, or the like.

A multilayer laminate can also be obtained by using the above laminate as an inner layer material. For example, first, a circuit is formed on a laminate by an additive method, a subtractive method, or the like, and the inner layer material is obtained by blackening the surface of the circuit with an acid solution. A laminate is formed by placing one or more sheets of the prepreg on one or both sides of the circuit forming surface of the obtained inner layer material and placing a metal foil on the outside thereof. A multi-layer laminate is obtained by integrally molding the laminate under heat and pressure. For forming the insulating layer, an insulating adhesive sheet, a resin-coated metal foil, or the like can be used instead of the prepreg. The same metal foil as that used for the laminate is used as the metal foil. Further, the heat and pressure molding can be performed under the same conditions as those described above. A multilayer printed wiring board is obtained by forming via holes and circuits on the surface of the obtained multilayer laminate by an additive method or a subtractive method. Further, by repeating the above method using this multilayer printed wiring board as an inner layer material, a further multilayer printed wiring board can be obtained.

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.

When an epoxy resin composition is prepared, a laminate is formed, and the laminate is heat-cured to form a laminate, the epoxy resin cured product can exhibit excellent heat resistance and flame retardancy.

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 K 7236, 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 K 7234 standard, ring and ball method. Specifically, an automatic softening point apparatus (ASP-MG4 manufactured by Meitec Co., Ltd.) was used.

GPC measurement: A body (manufactured by Tosoh Corporation, HLC-8220GPC) equipped with columns (manufactured by Tosoh Corporation, TSKgelG4000H _XL , TSKgelG3000H _XL , TSKgelG2000H _XL ) in series was used, and the column temperature was set to 40 ° C. Tetrahydrofuran (THF) was used as the eluent, the flow rate was 1 mL/min, and the detector was a differential refractive index detector.The measurement sample was dissolved in 10 mL of THF in 0.1 g of the sample, and filtered through a microfilter. Data was processed using GPC-8020 model II version 6.00 manufactured by Tosoh Corp. From the obtained chromatogram, the amounts of n = 0 component and n = 5 or more components were calculated. , Standard monodisperse polystyrene (manufactured by Tosoh Corporation, A-500, A-1000, A-2500, A-5000, F-1, F-2, F-4, F-10, F-20, F- 40, F-80, F-128), the number average molecular weight (Mn), weight average molecular weight (Mw), and dispersity (Mw/Mn) were measured.

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).

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

Copper foil peel strength and interlayer adhesive strength: Measured according to JIS C 6481 standards, and the interlayer adhesive strength was measured by peeling off between the 7th and 8th layers.

[Epoxy resin]
A1: Biphenol aralkyl type epoxy resin obtained in Synthesis Example 2 A2: Triphenolmethane type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., EPPN-501H, epoxy equivalent 166)
A3: Phosphorus-containing epoxy resin (Nippon Steel & Sumikin Chemical Co., Ltd., FX-1225, epoxy equivalent 318, phosphorus content 2.5%)
A4: Phosphorus-containing epoxy resin (manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., YDFR-1320, epoxy equivalent 763, phosphorus content 5.0%)

[Curing agent]
B1: Phenol novolac resin (manufactured by Aica Kogyo Co., Ltd., Shaunol BRG-557, phenolic hydroxyl group equivalent 105, softening point 80 ° C.)
B2: Dicyandiamide (manufactured by Nippon Carbide Industry Co., Ltd., DICY, active hydrogen equivalent 21)
B3: Phenolic resin (manufactured by Gun Ei Chemical Industry Co., Ltd., Resitop TPM-100, phenol hydroxyl equivalent 98, softening point 108 ° C.)

[Curing accelerator]
C1: 2-ethyl-4-methylimidazole (manufactured by Shikoku Kasei Co., Ltd., Curesol 2E4MZ)

Synthesis example 1
246 parts of 4,4'-biphenol, 380 parts of diethylene glycol dimethyl ether, and 133 parts of 4,4'-bischloromethylbiphenyl were charged into a reactor equipped with a stirrer, thermometer, nitrogen inlet tube, and cooling tube, and a nitrogen stream was introduced. While stirring, the temperature was raised to 170° C. and the mixture was reacted for 2 hours. After the reaction, all diethylene glycol dimethyl ether was distilled off under reduced pressure, 311 parts of toluene and 104 parts of methyl isobutyl ketone were added, stirred and mixed, cooled to room temperature, and unreacted raw material 4,4'-biphenol precipitated was filtered off. After removing it separately, toluene and methyl isobutyl ketone were distilled off to obtain 187 parts of a biphenylaralkyl type phenol resin. The phenolic hydroxyl equivalent was 155 and the softening point was 130°C.

Synthesis example 2
127 parts of the biphenylaralkyl-type phenolic resin obtained in Synthesis Example 1 was put into a reaction apparatus equipped with a stirrer, a thermometer, a nitrogen inlet tube, and a cooling tube, and 448 parts of epichlorohydrin and 67 parts of diethylene glycol dimethyl ether were added. and warmed to 60°C. Under a reduced pressure of 110 mmHg, 64 parts of a 49% sodium hydroxide aqueous solution was added dropwise over 4 hours while maintaining the temperature at 58-62°C. 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 toluene was added to dissolve the product. 180 parts of water was added to dissolve the by-produced salt, and the solution was allowed to stand to separate and remove the lower salt solution. After neutralization with an aqueous solution of phosphoric acid, the resin solution was washed with water until the washings became neutral and filtered. The mixture was heated to 180° C. under a reduced pressure of 5 mmHg to distill off toluene to obtain 95 parts of a biphenyl aralkyl type epoxy resin (A1). The epoxy equivalent is 218, the softening point is 97° C., the n=0 component is 4.3 area %, the n=5 or more component is 30.5 area %, the Mn is 1440, the Mw is 3200, and the Mw/Mn is 2.22. there were.

Example 1
10 parts of A1, 90 parts of A3, 35 parts of B1, and 0.05 parts of C1 are blended, and dissolved in a mixed solvent prepared with MEK, propylene glycol monomethyl ether, and N,N-dimethylformamide to form an epoxy resin composition. got a 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 glass transition temperature, copper foil peel strength, interlayer adhesion and flame retardancy of the laminate.

Examples 2-7
A1 to A4 as an epoxy resin, B1 to B3 as a curing agent, and C1 as a curing accelerator are blended in the amounts (parts) shown in Table 1, and the same operation as in Example 1 is performed to obtain a laminate and a test piece. got At this time, the amount of the 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. The phosphorus content in the table is the value for the epoxy resin composition.

Comparative Examples 1-8
A2 to A4 as an epoxy resin, B1 to B3 as a curing agent, and C1 as a curing accelerator are blended in the amounts (parts) shown in Table 2, and the same operation as in Example 1 is performed to obtain a laminate and a test piece. got The same test as in Example 1 was conducted and the results are shown in Table 2.

As is clear from these results, an epoxy resin composition using a biphenyl aralkyl type epoxy resin and a phosphorus-containing epoxy resin can be obtained as an epoxy resin composition having both high heat resistance and flame retardancy.

Claims (5)

An epoxy resin composition containing an epoxy resin and a curing agent as essential components, wherein the epoxy resin comprises a biphenyl aralkyl type epoxy resin represented by the following general formula (1) and a phosphorus-containing epoxy resin, and 3. An epoxy resin composition comprising 5% by mass or more and 30% by mass or less of the biphenyl aralkyl type epoxy resin .

(Here, n is the number of repetitions and represents a number of 0 or more, the average value is a number of 1.3 to 20, R ¹ , R ² and R ³ are each independently a hydrogen atom or a carbon number of 1 represents a hydrocarbon group of ~8.) The phosphorus-containing epoxy resin has an epoxy equivalent of 200 to 1000 g/eq. The epoxy resin composition according to claim 1, wherein the phosphorus content is 1.0 to 6.0% by mass. A prepreg using the epoxy resin composition according to claim 1 or 2. A laminate using the epoxy resin composition according to claim 1 or 2. A printed wiring board using the epoxy resin composition according to claim 1 or 2.