CN107400198B

CN107400198B - Epoxy resin composition and cured product thereof

Info

Publication number: CN107400198B
Application number: CN201710360852.5A
Authority: CN
Inventors: 高岛智行; 石原一男; 宗正浩
Original assignee: Nippon Steel and Sumikin Chemical Co Ltd
Current assignee: Nippon Steel Chemical and Materials Co Ltd
Priority date: 2016-05-20
Filing date: 2017-05-18
Publication date: 2020-12-22
Anticipated expiration: 2037-05-18
Also published as: KR20170131267A; KR102351752B1; JP6924000B2; TW201809130A; TWI724167B; JP2017206641A; CN107400198A

Abstract

The invention provides an epoxy resin composition and a cured product thereof, which have excellent performances such as heat resistance, dielectric property and adhesive property and are useful in applications such as lamination, molding, casting and adhesion. The epoxy resin composition contains an epoxy resin (A) and a hardener (B), wherein the epoxy resin (A) contains an oxazolidone ring-containing epoxy resin (a) obtained from an epoxy resin (c) represented by the following formula (1) and an isocyanate compound (d), and the hardener (B) contains a bisphenol compound (B1) represented by the following formula (2) and a novolac phenol compound (B2) represented by the following formula (3). X¹、X²Is a cycloalkylene group having a ring member number of 5 to 8 and having a hydrocarbon group as a substituent, A¹Is benzene ring, naphthalene ring or biphenyl ring, and T is methylene or other cross-linking group. [ formula 1]

Description

Epoxy resin composition and cured product thereof

Technical Field

The present invention relates to an epoxy resin composition capable of providing a cured product having excellent low dielectric characteristics, high heat resistance, high adhesiveness, and the like, and a cured product thereof.

Background

Since the progress of electric and electronic equipment is remarkable, and particularly, communication equipment performs large-capacity and high-speed processing of data, there is a strong demand for dielectric properties such as low dielectric constant and low dielectric loss tangent of electronic equipment members such as printed wiring boards and sealing materials used for these. Further, the wiring of the metal foil secures the adhesion by roughening the adhesion surface, but there is also a problem that the adhesion needs to be maintained by suppressing roughening for high-speed processing.

With the recent dramatic increase in the amount of information, infrastructure equipment such as portable equipment and base stations that support the portable equipment, which is one of the applications of printed wiring boards, has been required to have higher functions. In portable devices, high multilayering and fine wiring are performed for the purpose of miniaturization, and a material having a lower dielectric constant is required for thinning a substrate, and a material having higher adhesiveness is required for reducing the adhesive surface due to fine wiring. In order to suppress attenuation of high-frequency signals in a substrate facing a base station, a material having a lower dielectric loss tangent is required.

The properties such as low dielectric constant, low dielectric loss tangent and high adhesion are derived to a large extent from the structures of an epoxy resin and a curing agent, which are matrix resins of printed wiring boards.

It is known that the dielectric constant is deteriorated by hydroxyl groups generated when the epoxy resin composition is cured. As one of the designs for reducing the number of hydroxyl groups, patent document 1 discloses an oxazolidone ring-containing epoxy resin in which an oxazolidone ring is formed by a reaction between an epoxy resin and an isocyanate. Examples of the epoxy resin as a raw material include a compound obtained by glycidylating a dihydric phenol such as bisphenol a, a compound obtained by glycidylating a tri (glycidyloxyphenyl) alkane, p-aminophenol or the like, and a compound obtained by glycidylating a novolak such as phenol novolak. However, none of the disclosed epoxy resins sufficiently satisfies the dielectric characteristics required for advanced functions in recent years, and the adhesiveness is also insufficient.

As a method for improving the dielectric characteristics of an epoxy resin, as shown by the formula of Clausius-moxotti (Clausius-mossoti), a reduction in molar polarizability and an increase in molar volume are effective. As a curing agent to which the effect of the increase in the molar volume is applied, a dicyclopentadiene phenol resin is disclosed in patent document 2. Patent document 3 discloses a substituted cycloalkylidene bisphenol such as 4,4' - (3,3, 5-trimethylcyclohexylidene) bisphenol, but does not disclose dielectric characteristics.

On the other hand, patent documents 4 and 5 disclose that aromatic modified phenol novolak as a curing agent is excellent in heat resistance, dielectric properties, and the like, but has a problem that the adhesive strength is likely to be insufficient.

[ Prior art documents ]

[ patent document ]

[ patent document 1] Japanese patent laid-open No. Hei 5-43655

[ patent document 2] Japanese patent laid-open publication No. 2015-535865

[ patent document 3] Japanese patent laid-open No. Hei 2-229181

[ patent document 4] Japanese patent laid-open No. 2010-235819

[ patent document 5] Japanese patent laid-open No. 2012-57079

Disclosure of Invention

[ problems to be solved by the invention ]

Accordingly, an object to be solved by the present invention is to provide an epoxy resin composition and a cured product thereof, which have excellent properties of low dielectric properties, high heat resistance and high adhesion and are useful for applications such as lamination, molding, casting and adhesion. Further, an epoxy resin composition and a cured product thereof are provided which have good flame retardancy without deteriorating the characteristics such as dielectric properties, heat resistance and adhesiveness even when a flame retardant is blended.

[ means for solving the problems ]

As a result of diligent research directed to materials having a low dielectric constant and a low dielectric loss tangent, the present inventors have found that an epoxy resin composition comprising an oxazolidone ring (oxazolidone ring) obtained by reacting an epoxy resin having a specific structure with an isocyanate compound and a curing agent comprising a specific bisphenol compound and a specific novolak phenol compound in combination achieves a low dielectric constant, a low dielectric loss tangent and a high glass transition temperature, which are not achieved by the prior art, and further, has good adhesion, and have completed the present invention. Further, it has been found that excellent flame retardancy is exhibited without deteriorating the properties such as dielectric properties, heat resistance and adhesiveness even when the flame retardant is used in combination.

That is, the present invention is an epoxy resin composition comprising an epoxy resin (a) and a curing agent (B), the epoxy resin composition being characterized in that: the epoxy resin (a) contains an oxazolidone ring-containing epoxy resin (a) obtained from an epoxy resin (c) represented by the following formula (1) and an isocyanate compound (d), and the hardener (B) contains a bisphenol compound (B1) represented by the following formula (2) and a novolak phenol compound (B2) represented by the following formula (3).

[ solution 1]

In the formula, X¹Represents a cycloalkylene group (cycloakylidine) having at least one C1-20 hydrocarbon group as a substituent and having a ring number of 5-8. R¹Each independently represents a hydrogen atom, a halogen atom, a halogenated hydrocarbon group having 1 to 20 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms and having a hetero atom. G represents a glycidyl group. n represents the number of repetitions, and the average value is 0 to 5.

[ solution 2]

In the formula, X²Represents a cycloalkylene group having 5 to 8 ring members and having at least one C1-20 hydrocarbon group as a substituent. R²Each independently represents a hydrogen atom, a halogen atom, a halogenated hydrocarbon group having 1 to 20 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms and having a hetero atom.

[ solution 3]

In the formula, A¹Each independently represents an aromatic ring group selected from a benzene ring, a naphthalene ring, or a biphenyl ring, and these aromatic ring groups may have a C1-49 hydrocarbon group which may have a hetero atom as a substituent, and have 0.1 to 2.5 substituents on average selected from a C6-48 aryl group, a C6-48 aryloxy group, a C7-49 aralkyl group, and a C7-49 aralkyloxy group. T represents any one of a divalent aliphatic cyclic hydrocarbon group and a divalent crosslinking group represented by the following formula (3a) or (3 b). k represents 1 or 2. m represents the number of repetitions, and the average value is 1.5 or more.

[ solution 4]

In the formula, R³And R⁴Each independently represents a hydrogen atom or a C1-20 hydrocarbon group which may have a hetero atom. R⁵And R⁶Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. A. the²An aromatic ring group selected from a benzene ring, a naphthalene ring and a biphenyl ring, and the aromatic ring group may have a C1-20 hydrocarbon group which may have a hetero atom as a substituent.

In the epoxy resin composition, a preferred embodiment of the present invention satisfies any one or more of the following requirements.

1) The mass ratio of the bisphenol compound (b1) to the novolak phenol compound (b2) is in the range of 5/95 to 95/5,

2) the bisphenol compound (b1) is 4,4'- (3,3, 5-trimethylcyclohexylidene) bisphenol or 4,4' - (3,3,5, 5-tetramethylcyclohexylidene) bisphenol,

3) the novolak phenol compound (b2) is a phenol compound represented by the following formula (4), or

4) The active hydrogen group of the curing agent (B) is 0.2 to 1.5 moles based on 1 mole of the epoxy group of the epoxy resin (A).

[ solution 5]

In the formula, R⁷Each independently represents a C1-6 hydrocarbon group, R⁸Is a substituent represented by the following formula (4 a). The average value of p is 0.1 to 2.5, q is 0 to 2, p + q is 0.1 to 3 in terms of average value, and m is the same as m in the formula (3).

[ solution 6]

In the formula, R⁹、R¹⁰And R¹¹Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms.

The present invention also provides an epoxy resin cured product obtained by curing the epoxy resin composition.

[ Effect of the invention ]

The epoxy resin composition of the present invention provides a cured product having a high glass transition temperature while maintaining good adhesion. Furthermore, the cured product of the present invention is excellent in dielectric properties, and exhibits good properties in applications of electronic materials requiring low dielectric constant and low dielectric loss tangent.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail.

The epoxy resin composition of the present invention contains an epoxy resin (a) and a curing agent (B). The epoxy resin (a) contains an oxazolidone ring-containing epoxy resin (a) as an essential component. The hardener (B) contains a bisphenol compound (B1) and a novolac phenol compound (B2) as essential components.

The epoxy equivalent (g/eq.) of the oxazolidone ring-containing epoxy resin (a) is preferably 200 to 1000, more preferably 220 to 700, still more preferably 230 to 500, and particularly preferably 250 to 400. If the epoxy equivalent is low, there is a concern that: the content of oxazolidone ring is reduced and the concentration of hydroxyl groups in the cured product is increased, thereby increasing the dielectric constant. In addition, when the epoxy equivalent is high, there is a concern that: the content of oxazolidone ring is increased more than necessary, and adverse effects such as deterioration of solvent solubility and increase of resin viscosity are increased due to the effect of improving dielectric characteristics. In addition, there are concerns that: the use of the cured product is problematic, for example, because the crosslink density of the cured product is low and the elastic modulus is low at the temperature of reflow soldering.

When the oxazolidone ring-containing epoxy resin (a) is used for a prepreg or a film material, the softening point is preferably 50 to 150 ℃, more preferably 60 to 135 ℃, and still more preferably 70 to 110 ℃. If the softening point is low, there is a concern that: when the resin varnish is impregnated into a glass cloth and then dried by heating in an oven, the amount of resin adhering decreases because of the low viscosity. If the softening point is high, the following may occur: the resin has a high viscosity, and therefore, impregnation properties in the prepreg are deteriorated, solubility in a solvent is deteriorated, or a diluted solvent remains in the resin without being volatilized during heat drying, and therefore, voids are generated when a laminate is produced, which causes a problem in use.

The oxazolidone ring-containing epoxy resin (a) can be advantageously obtained by a method for producing an oxazolidone ring-containing epoxy resin described later, but an oxazolidone ring-containing epoxy resin containing by-products and the like is usually obtained. Here, the by-products and the like may be interpreted to mean that unreacted substances are included. The oxazolidone ring-containing epoxy resin (a) may also be a reaction product containing the by-product and the like.

The oxazolidone ring-containing epoxy resin (a) is obtained by reacting an epoxy resin (c) represented by the formula (1) with an isocyanate compound (d). In this reaction, the epoxy group reacts with the isocyanate group to form an oxazolidone ring. Typically, when a difunctional epoxy resin is used together with an isocyanate compound, the difunctional epoxy resin has a structural unit represented by the following formula.

-E¹-O-CH₂-Ox¹-Ic¹-Ox¹-CH₂-O-

Here, E¹A residue formed by removing a glycidyl ether group from an epoxy resin, Ox¹Is an oxazolidinone ring, Ic¹Is a residue resulting from the removal of an isocyanate group from an isocyanate.

In the formula (1), R¹Each independently represents a hydrogen atom, a halogen atom, a halogenated hydrocarbon group having 1 to 20 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms and having a hetero atom.

In the present specification, the hydrocarbon group which may have a heteroatom may be a heteroatom-containing hydrocarbon group in which a part of the carbon of the hydrocarbon group or the carbon constituting the hydrocarbon group is a heteroatom. The hydrocarbon group containing a heteroatom is a hydrocarbon chain or a hydrocarbon ring in which a part of carbons constituting the hydrocarbon chain or the hydrocarbon ring is a heteroatom, and in the case of a hydrocarbon chain, the hydrocarbon chain may be located at the middle or the end. The hetero atom is an oxygen atom, a nitrogen atom, a sulfur atom, or the like, and preferably an oxygen atom. In the case where the hetero atom is an oxygen atom, it is positioned at the terminal, and the hydrocarbon group is an alkyl group, an aryl group or an aralkyl group, it may be an alkoxy group, an aryloxy group or an aralkyloxy group. In addition, the heteroatom may be in a hydroxyl-like substituent.

Examples of the halogen atom include: fluorine, chlorine, bromine, iodine.

The halogenated hydrocarbon group having 1 to 20 carbon atoms includes preferably a halogenated alkyl group having 1 to 20 carbon atoms, preferably 1 to 6 carbon atoms.

The hydrocarbon group having 1 to 20 carbon atoms, which may have a hetero atom, may be straight, branched or cyclic, and is preferably an aliphatic hydrocarbon group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms or an aromatic hydrocarbon group having 6 to 20 carbon atoms, and more preferably an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, a cycloalkoxy group having 5 to 8 carbon atoms, an aryl group having 6 to 14 carbon atoms, an aryloxy group having 6 to 14 carbon atoms, an aralkyl group having 7 to 15 carbon atoms or an aralkyloxy group having 7 to 15 carbon atoms. These may have a part of carbon as a hetero atom.

Examples of the alkyl group or alkoxy group having 1 to 8 carbon atoms include: methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, hexyl, methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, tert-butoxy, hexyloxy and the like, and examples of cycloalkyl or cycloalkoxy having 5 to 8 carbon atoms include cyclohexyl, cyclohexyloxy and the like, and examples of aryl or aryloxy having 6 to 14 carbon atoms include: phenyl, tolyl, o-xylyl, naphthyl, indanyl, phenoxy, naphthoxy, and the like, and examples of the aralkyl group or aralkyloxy group having 7 to 15 carbon atoms include: benzyl, phenethyl, 1-phenylethyl, naphthylmethyl, anthrylmethyl, benzyloxy, naphthylmethoxy, anthrylmethoxy, etc., but the same or different groups may be used.

When flame retardancy is required, a halogen atom or a halogenated hydrocarbon group having 1 to 20 carbon atoms is preferably used as a substituent, and the halogen atom is preferably a bromine atom. Examples of the halogenated hydrocarbon group having 1 to 20 carbon atoms include a methyl bromide group and the like. In the case of a non-halogen flame-retardant epoxy resin composition described later, a substituent having such a halogen atom is not included.

From the viewpoint of ease of acquisition and physical properties of the cured product, R is preferred¹Is hydrogen atom, methyl, methoxy, phenyl, benzyl, 1-phenylethyl or phenoxy. R¹Relative to the substitution position of with X¹The bonded carbon atom is either ortho, para, or meta, preferably ortho or para, and more preferably ortho.

In the formula (1), X¹A cycloalkylene group having 5 to 8 ring members and having at least one hydrocarbon group having 1 to 20 carbon atoms as a substituent. The cycloalkane ring constituting the cycloalkylene group is any one of a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, or a cyclooctane ring, and is preferably a cyclopentane ring or a cyclohexane ring.

The C1-20 hydrocarbon group as a substituent is preferably a structure having a large molecular weight, and is preferably an alkyl group having 1-8 carbon atoms, a cycloalkyl group having 5-8 carbon atoms, an aryl group having 6-14 carbon atoms, or an aralkyl group having 7-15 carbon atoms from the viewpoint of dielectric characteristics. Examples of the alkyl group having 1 to 8 carbon atoms include: methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, hexyl and the like, examples of cycloalkyl groups having 5 to 8 carbon atoms include cyclohexyl and the like, and examples of aryl groups having 6 to 14 carbon atoms include: phenyl group, tolyl group, o-xylyl group, naphthyl group, and the like, and examples of the aralkyl group having 7 to 15 carbon atoms include: benzyl group, phenethyl group, 1-phenylethyl group and the like, but are not limited thereto, and when a plurality of groups are present, they may be the same or different. From the viewpoint of ease of acquisition and physical properties of the cured product, the substituent is preferably an alkyl group having 1 to 3 carbon atoms or a phenyl group, and more preferably a methyl group.

In addition, the cycloalkylene group is a1, 1-cycloalkylene group, and the substituent restricts the movement of the cycloalkane ring due to a steric repulsive force acting between two benzene rings bonded to the carbon at the 1-position of the cycloalkylene group or the substituent, so that the dielectric characteristics are improved and the heat resistance is also improved. The substitution position may be bonded to an arbitrary position if it is a position that can restrict the mobility, but is preferably bonded to a carbon atom near the 1-position of the cycloalkylene group. Preferred positions of the substituents are carbon atoms in the 2-or 5-position of the cyclopentane ring. In the cyclohexane ring, the carbon atom is in the 2-, 3-, 5-or 6-position, more preferably in the 2-or 6-position. In the cycloheptane ring, a carbon atom at the 2-, 3-, 6-or 7-position, more preferably a carbon atom at the 2-or 7-position. In the cyclooctane ring, the carbon atom is a carbon atom at the 2-, 3-, 4-, 6-, 7-or 8-position, more preferably a carbon atom at the 2-, 3-, 7-or 8-position, and still more preferably a carbon atom at the 2-or 8-position. Among them, there are cases where it is difficult to substitute the carbon atom closest to the 1-position due to the influence of steric hindrance with the adjacent benzene ring, and in such cases, the substituent is suitably bonded to the second closest carbon atom. For example, in the cyclohexane ring, the carbon atom at the 2-position or 6-position is closest to the 1-position, but in the case where substitution is difficult due to steric hindrance, a substituent may be bonded to the second closest 3-position or 5-position.

The number of the substituents is preferably three or more, more preferably three, from the viewpoint of physical properties such as heat resistance of the cured product.

In the formula (1), n is a repeating number, and the average value (number average) thereof is 0 to 5, preferably 0 to 3, more preferably 0 to 1, further preferably 0 to 0.5, and most preferably 0. The number of repetitions may be any one of 0 to 5, or may be a mixture of 0 to 5.

The epoxy equivalent of the epoxy resin (c) is preferably 100 to 500, more preferably 125 to 400, and further preferably 150 to 300. The alcoholic hydroxyl group equivalent (g/eq.) is preferably 3000 or more, more preferably 4000 or more, and still more preferably 5000 or more. The alcoholic hydroxyl group is not preferable because the alcoholic hydroxyl group equivalent is small because it reacts with isocyanate to form a urethane bond and lowers the glass transition point of the cured product. Further, since the concentration of hydroxyl groups in the cured product is increased, the dielectric constant of the cured product is increased, which is not preferable.

The epoxy resin (c) includes epoxy resins obtained from a bisphenol compound containing a cycloalkylene group represented by the formula (2) and an epihalohydrin. Examples thereof include: 4,4'- (2-methylcyclohexylidene) bisphenol glycidyl ether, 4' - (3-methylcyclohexylidene) bisphenol glycidyl ether, 4'- (4-methylcyclohexylidene) bisphenol glycidyl ether, 4' - (3,3, 5-trimethylcyclohexylidene) -bis-phenylphenol glycidyl ether, 4'- (3,3, 5-trimethylcyclohexylidene) -bis-dimethylphenol glycidyl ether, 4' - (3,3, 5-trimethylcyclohexylidene) -bis-tert-butylphenol glycidyl ether, etc., however, the method is not limited to these, and may be used alone or in combination of two or more.

The epoxy resin (c) is preferably an epoxy resin (c1) represented by the following formula (5) obtained from 4,4' - (3,3, 5-trimethylcyclohexylidene) bisphenol and epihalohydrin, from the viewpoint of easiness of obtaining and good physical properties of the cured product. In the formula (5), n is the same as n in the formula (1).

[ solution 7]

In the production of the oxazolidone ring-containing epoxy resin (a), a desired oxazolidone ring-containing epoxy resin can be obtained by the reaction of the epoxy resin (c) with the isocyanate compound (d). The isocyanate compound (d) may be any isocyanate compound having an average of 1.8 or more isocyanate groups (-N ═ C ═ O) in one molecule, that is, a polyfunctional isocyanate compound having substantially two or more functional groups, and known and conventional isocyanate compounds may be used. The monofunctional isocyanate compound may be contained in a small amount, but it is effective for the purpose of reducing the degree of polymerization because it serves as an end group, but the degree of polymerization is not increased.

Specifically, there may be mentioned: 2, 4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, 3, 5-tolylene diisocyanate, 2' -diphenylmethane diisocyanate, 2,4' -diphenylmethane diisocyanate, 4' -diphenylmethane diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, tetramethylxylylene diisocyanate, 1, 4-naphthalenediyl diisocyanate, 1, 5-naphthalenediyl diisocyanate, 2, 6-naphthalenediyl diisocyanate, 2, 7-naphthalenediyl diisocyanate, naphthalene-1, 4-diylbis (methylene) diisocyanate, naphthalene-1, 5-diylbis (methylene) diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, biphenyl-4, 4 '-diisocyanate, 3' -dimethylbiphenyl-4, 4 '-diisocyanate, 2,3' -dimethoxybiphenyl-4, 4 '-diisocyanate, diphenylmethane-4, 4' -diisocyanate, 3 '-dimethoxydiphenylmethane-4, 4' -diisocyanate, 4 '-dimethoxydiphenylmethane-3, 3' -diisocyanate, diphenyl sulfite-4, 4 '-diisocyanate, diphenylsulfone-4, 4' -diisocyanate, bicyclo [2.2.1] heptane-2, 5-diylbis-methylene diisocyanate, bicyclo [2.2.1] heptane-2, 6-diylbis-methylene diisocyanate, isophorone diisocyanate, 4,4' -methylenedicyclohexyl diisocyanate, lysine diisocyanate, 1-bis (isocyanotomethyl) cyclohexane, 1, 2-bis (isocyanotomethyl) cyclohexane, 1, 3-bis (isocyanotomethyl) cyclohexane, 1, 4-bis (isocyanotomethyl) cyclohexane, 1, 3-cyclohexylene diisocyanate, 1, 4-cyclohexylene diisocyanate, 4-methyl-1, 3-cyclohexylene diisocyanate, 2-methyl-1, 3-cyclohexylene diisocyanate, 1-methylbenzene-2, 4-diisocyanate, 1-methylbenzene-2, 5-diisocyanate, 1-methylbenzene-2, 6-diisocyanate, 1-methylbenzene-3, 5-diisocyanate, hexamethylene diisocyanate, 2, 4-trimethylhexamethylene diisocyanate, 2,4, 4-trimethylhexamethylene diisocyanate, methane diisocyanate, ethane-1, 2-diisocyanate, propane-1, 3-diisocyanate, butane-1, 1-diisocyanate, butane-1, 2-diisocyanate, butane-1, 4-diisocyanate, 2-butene-1, 4-diisocyanate, 2-methylbutene-1, 4-diisocyanate, 2-methylbutane-1, 4-diisocyanate, pentane-1, 5-diisocyanate, 2-dimethylpentane-1, 5-diisocyanate, 2, 4-trimethylhexamethylene diisocyanate, 2,4, 4-trimethylhexamethylene diisocyanate, butane-1, 1-diisocyanate, butane-1, 2-diisocyanate, 2-dimethylpentane-1, 4-diisocyanate, 2-dimethyl, Hexane-1, 6-diisocyanate, heptane-1, 7-diisocyanate, octane-1, 8-diisocyanate, nonane-1, 9-diisocyanate, decane-1, 10-diisocyanate, dimethylsilane diisocyanate, diphenylsilane diisocyanate and other difunctional isocyanate compounds, or triphenylmethane triisocyanate, 1,3, 6-hexamethylene triisocyanate, 1, 8-diisocyanate-4-isocyanatomethyloctane, bicycloheptane triisocyanate, tris (isocyanatophenyl) thiophosphate, lysine ester triisocyanate, undecane triisocyanate, tris (4-phenylisocyanatothiophosphate) -3,3',4,4' -diphenylmethane tetraisocyanate, mixtures thereof, and mixtures thereof, A polyfunctional isocyanate compound such as polymethylene polyphenyl isocyanate, a polymer such as a dimer or trimer of the above isocyanate compound, a block isocyanate masked with a blocking agent such as alcohol or phenol, a biscarbamate compound, etc., but the present invention is not limited thereto. These isocyanate compounds may be used alone, or two or more of them may be used in combination.

Among these isocyanate compounds, a difunctional isocyanate compound or a trifunctional isocyanate compound is preferable, and a difunctional isocyanate compound is more preferable. When the number of functional groups of the isocyanate compound is large, the storage stability may be lowered, and when the number of functional groups of the isocyanate compound is small, the heat resistance and the dielectric properties may not be improved. Further preferred isocyanate compounds are those selected from the group consisting of 2, 4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, 3, 5-tolylene diisocyanate, 2' -diphenylmethane diisocyanate, 2,4' -diphenylmethane diisocyanate, 4' -diphenylmethane diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, tetramethylxylylene diisocyanate, 1, 4-naphthalenediyl diisocyanate, 1, 5-naphthalenediyl diisocyanate, 2, 6-naphthalenediyl diisocyanate, 2, 7-naphthalenediyl diisocyanate, 3' -dimethylbiphenyl-4, 4' -diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, cyclohexane-1, 4-diyl diisocyanate, and mixtures thereof, Cyclohexane-1, 3-diylbis-methylene diisocyanate, cyclohexane-1, 4-diylbis-methylene diisocyanate, hexamethylene diisocyanate, 2, 4-trimethylhexamethylene diisocyanate, 2,4, 4-trimethylhexamethylene diisocyanate, 4,4' -methylenebiscyclohexyl diisocyanate, bicyclo [2.2.1] heptane-2, 5-diylbis-methylene diisocyanate, bicyclo [2.2.1] heptane-2, 6-diylbis-methylene diisocyanate, and isophorone diisocyanate. Among these, particularly preferred isocyanate compounds (d) are at least one selected from the group consisting of 2, 4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, 3, 5-tolylene diisocyanate, 2' -diphenylmethane diisocyanate, 2,4' -diphenylmethane diisocyanate, 4' -diphenylmethane diisocyanate, cyclohexane-1, 3-diylbis-methylene diisocyanate, cyclohexane-1, 4-diylbis-methylene diisocyanate, and isophorone diisocyanate.

The reaction of the epoxy resin (c) with the isocyanate compound (d) can be carried out by a known method. The specific reaction method comprises the following steps: (1) a method in which the epoxy resin (c) is melted, the moisture in the epoxy resin is removed by a method such as purging with a dry gas or reducing the pressure in the system, and then the isocyanate compound (d) and a catalyst are added to the mixture to react with each other; or (2) a method in which the epoxy resin (c) is mixed with a catalyst in advance, water in the epoxy resin is removed by a method such as purging with a dry gas or reducing the pressure in the system, and then the isocyanate compound (d) is added to the mixture to carry out the reaction. The water content in the system at this time is preferably 0.5% by mass or less, more preferably 0.1% by mass or less, and still more preferably 0.05% by mass or less. In any method, if necessary, a non-reactive solvent may be used, for example, when the resin has a high viscosity and is difficult to stir. In this manner, the epoxy group of the epoxy resin (c) reacts with the isocyanate group of the isocyanate compound (d) to form an oxazolidone ring. When n in formula (1) is 1 or more, the isocyanate compound (d) contains an alcoholic hydroxyl group which undergoes an addition reaction with an isocyanate group of the isocyanate compound (d) to form a urethane bond. In the case where n in formula (1) is 0, there are impurities added by the urethane bond. The oxazolidone ring-containing epoxy resin (a) used in the present invention contains not only an oxazolidone ring-containing epoxy resin but also a raw material epoxy resin (c) which is not usually reacted. In addition, impurities that undergo an addition reaction using a urethane bond may be included. Even a mixture of these is included in the oxazolidone ring-containing epoxy resin (a) used in the present invention.

The epoxy equivalent (No) of the oxazolidone ring-containing epoxy resin (a) can be predicted from the following calculation formula depending on the kind and charged amount of the raw material. Conversely, the charged amounts of the epoxy resin (c) and the isocyanate compound (d) can be determined from the epoxy equivalent (Ne) of the epoxy resin (c) and the equivalent (Ni) of the isocyanate group of the isocyanate compound (d) for the oxazolidone ring-containing epoxy resin (a) having a desired epoxy equivalent according to the following calculation formula. The unit of equivalent is g/eq, and the same applies hereinafter unless otherwise specified.

[ number 1]

Me: amount of epoxy resin (c) charged (g)

Mi: amount (g) of isocyanate Compound (d) charged

For example, when the epoxy equivalent of the epoxy resin (c) is 220 and the equivalent of the isocyanate group of the isocyanate compound (d) is 125, the charged amount of the oxazolidone ring-containing epoxy resin (a) is about 500, and the isocyanate compound (d) is 30 parts by mass based on 100 parts by mass of the epoxy resin (c) according to the above calculation formula.

The oxazolidone ring-containing epoxy resin (a) used in the present invention preferably has an oxazolidone ring modification ratio of 0.15 to 0.6, more preferably 0.2 to 0.5, and even more preferably 0.25 to 0.45, from the viewpoints of suppression of high viscosity, securing of solvent solubility, or improvement of toughness, adhesiveness, and electrical characteristics. When the rate of modification of the oxazolidinone ring is high, the resulting polymer may become a macromolecule or have a high viscosity, which may result in a decrease in the solubility of the solvent. Further, when the rate of modification of the oxazolidone ring is small, the number of rigid oxazolidone rings having high molecular interaction is small, the effect of improving the heat resistance and adhesiveness of the cured product is insufficient, the number of free hydroxyl groups generated during curing is also large, and the effect of improving the electrical characteristics is also insufficient. Since the rate of modification of the oxazolidinone ring is substantially determined by the ratio of the epoxy group to the isocyanate group to be used, the rate of modification of the oxazolidinone ring is defined by the following formula in the present specification.

Oxazolidone ring modification ratio ═ (isocyanate group mol)/(epoxy group mol)

For example, in the case of the oxazolidone ring-containing epoxy resin having an epoxy equivalent of about 500, the rate of modification of the oxazolidone ring is 0.53.

Specific examples of the non-reactive solvent that can be used by the reaction of the epoxy resin (c) and the isocyanate compound (d) include: hydrocarbons such as hexane, heptane, octane, decane, dimethylbutane, pentene, cyclohexane, methylcyclohexane, benzene, toluene, xylene and ethylbenzene, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, ethers such as diethyl ether, isopropyl ether, dibutyl ether, diisoamyl ether, methylphenyl ether, ethylphenyl ether, pentylphenyl ether, ethylbenzyl ether, dioxane, methylfuran, tetrahydrofuran, diethylene glycol dimethyl ether, ethylene glycol diethyl ether and methyl ethyl carbitol, esters such as methyl cellosolve acetate, butyl cellosolve acetate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate and diethyl oxalate, amides such as N-methyl-2-pyrrolidone, N-dimethylacetamide and N, N-dimethylformamide, and lactones such as γ -butyrolactone, or sulfoxides such as dimethyl sulfoxide, ureas such as tetramethylurea, or halogenated hydrocarbons such as methylene chloride, 1, 2-dichloroethane, 1, 4-dichlorobutane, chlorobenzene, and o-dichlorobenzene, but the non-reactive solvent is not limited thereto, and these solvents may be used alone or two or more kinds may be used in combination. The amount of these solvents used is preferably 1 to 900 parts by mass, more preferably 5 to 100 parts by mass, based on 100 parts by mass of the epoxy resin (c).

The reaction of the epoxy resin (c) and the isocyanate compound (d) is preferably carried out with the addition of a catalyst. The addition temperature of the catalyst is preferably in the range of room temperature to 150 ℃, more preferably in the range of room temperature to 100 ℃.

The reaction temperature is preferably 100 to 250 ℃, more preferably 100 to 200 ℃, and further preferably 120 to 160 ℃. If the reaction temperature is low, the formation of the oxazolidone ring cannot be sufficiently advanced, and the trimerization reaction of the isocyanate group forms an isocyanurate ring. When the reaction temperature is high, the molecular weight locally increases, and the formation of insoluble gel components increases. Therefore, it is preferable to adjust the rate of addition of the isocyanate compound (d) and maintain the reaction temperature at an appropriate temperature. By appropriately controlling the reaction conditions, the oxazolidone ring can be formed substantially quantitatively from the epoxy group of the epoxy resin (c) and the isocyanate group of the isocyanate compound (d).

The reaction time is preferably in the range of 15 minutes to 10 hours, more preferably 30 minutes to 8 hours, and still more preferably 1 hour to 5 hours after the end of the addition of the isocyanate compound (d). If the reaction time is short, a large amount of isocyanate groups may remain in the product, and if the reaction time is long, the productivity may be significantly reduced.

The type of the catalyst used in the reaction is not particularly limited as long as it is a basic catalyst. Specifically, there may be mentioned: lithium compounds such as lithium chloride and lithium butoxide, boron trifluoride complex salts, quaternary ammonium salts such as tetramethylammonium chloride, tetramethylammonium bromide, tetraethylammonium bromide, tetrabutylammonium bromide, tetramethylammonium iodide, tetraethylammonium iodide and tetrabutylammonium iodide, tertiary amines such as dimethylaminoethanol, triethylamine, tributylamine, benzyldimethylamine, N-methylmorpholine, N '-dimethylpiperazine and 1, 4-diethylpiperazine, phosphines such as triphenylphosphine and tris (2, 6-dimethoxyphenyl) phosphine, pentyltriphenylphosphonium bromide, diallyldiphenylphosphonium bromide, ethyltriphenylphosphonium chloride, ethyltriphenylphosphonium bromide, ethyltriphenylphosphonium iodide, butyltriphenylphosphonium chloride, butyltriphenylphosphonium bromide, butyltriphenylphosphonium iodide, tetrabutylphosphonium acetate-acetic acid complex, tetrabutylphosphonium acetate, quaternary ammonium salts such as tetramethylammonium chloride, tetramethylammonium bromide, tetraethylammonium bromide, tetrabutylammonium bromide, N-methylmorpholine, N' -dimethylpiperazine and 1, 4-diethylpiperazine, phosphines such as, Phosphonium salts such as tetrabutylphosphonium chloride, tetrabutylphosphonium bromide and tetrabutylphosphonium iodide, combinations of triphenylantimony and iodine, imidazoles such as 2-phenylimidazole, 2-methylimidazole and 2-ethyl-4-methylimidazole, and the like, but the catalyst is not limited thereto, and these catalysts may be used alone or two or more kinds may be used in combination. Further, the liquid may be divided and used several times.

Among these catalysts, quaternary ammonium salts, tertiary amines, phosphines, and phosphonium salts are preferable, and tetramethylammonium iodide is more preferable in terms of reaction activity and reaction selectivity. If the catalyst has a low reactivity, the reaction time may be long, which may result in a decrease in productivity, and if the catalyst has a low reaction selectivity, the polymerization reaction between epoxy groups may proceed, which may result in failure to obtain desired physical properties.

The amount of the catalyst used is not particularly limited, but is 0.0001 to 5% by mass, preferably 0.0005 to 1% by mass, more preferably 0.001 to 0.5% by mass, and still more preferably 0.002 to 0.2% by mass, based on the total mass of the epoxy resin (c) and the isocyanate compound (d). If the amount of the catalyst is large, the self-polymerization reaction of the epoxy group proceeds in some cases, and thus the resin viscosity becomes high. In addition, the self-polymerization reaction of isocyanate is promoted, and the generation of oxazolidone ring is inhibited. Further, there is a fear that: the produced resin remains as impurities, and in various applications, particularly when used as a material for a laminate or a sealing material, the resulting resin has reduced insulation properties or reduced moisture resistance.

The hardener (B) contains the bisphenol compound (B1) represented by the formula (2) and the novolac phenol compound (B2) represented by the formula (3). The mixing ratio (b1/b 2; mass ratio) of the bisphenol compound (b1) to the novolak phenol compound (b2) is preferably 5/95 to 95/5, more preferably 10/90 to 10, still more preferably 20/80 to 80/20, and particularly preferably 30/70 to 70/30. The effect of the present invention can be exhibited to the maximum extent when the epoxy resin (a) is only an oxazolidone ring-containing epoxy resin (a) and the curing agent (B) is only a mixture of a bisphenol compound (B1) and a novolac phenol compound (B2). When the epoxy resin composition contains the above-mentioned combination, the effect of the content can be added as compared with the case where the epoxy resin composition does not contain the above-mentioned combination, and therefore, the amount of the addition can be small.

The content of the oxazolidone ring-containing epoxy resin (a) in the epoxy resin (a) is preferably 5 to 100% by mass, more preferably 20 to 100% by mass, even more preferably 50 to 100% by mass, particularly preferably 70 to 100% by mass, and most preferably 100% by mass. The content of the mixture of the bisphenol compound (B1) and the novolac phenol compound (B2) in the curing agent (B) is preferably 5 to 100% by mass, more preferably 20 to 100% by mass, even more preferably 50 to 100% by mass, particularly preferably 70 to 100% by mass, and most preferably 100% by mass. When a reaction product containing by-products or the like is used as the oxazolidone ring-containing epoxy resin (a), the mass of the reaction product can be calculated as the mass of the oxazolidone ring-containing epoxy resin (a) except for the case where the content of the oxazolidone ring-containing epoxy resin (a) in the reaction product is significantly small (for example, 20% by mass or less).

The bisphenol compound (b1) is represented by the formula (2). In the formula (2), R²Each independently represents a hydrogen atom, a halogen atom, a halogenated hydrocarbon group having 1 to 20 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms and having a hetero atom. These are reacted with R of the formula (1)¹The same as the description in (1). In addition, X²A cycloalkylene group having 5 to 8 ring members and at least one hydrocarbon group having 1 to 20 carbon atoms as a substituent. These are reacted with X of formula (1)¹The same as the description in (1).

The bisphenol compound (b1) can be obtained by reacting a corresponding cyclic aliphatic ketone with a phenol. Specific examples of the bisphenol compound (b1) include, but are not limited to, cycloalkylene-containing bisphenol compounds as shown below. Further, a residue obtained by removing two hydroxyphenyl groups (in the case where a substituent other than hydrogen is present) from the following bisphenol compound is X²Which is also preferred X¹. The substituents identically substituted for the two hydroxyphenyl groups being R²Which is also preferred R¹。

[ solution 8]

These exemplary cycloalkylene group-containing bisphenol compounds can be produced by the method disclosed in, for example, Japanese patent laid-open publication No. 4-282334 or Japanese patent laid-open publication No. 2015-51935, and can be obtained as commercially available products, for example: BisP-TMC, BisOC-TMC, BisP-MZ, BisP-3MZ, BisP-IPZ, BisCR-IPZ, Bis26X-IPZ, BisOCP-IPZ, BisP-nBZ, BisOEP-2HBP (trade name, manufactured by chemical industries, Ltd., Japan), and the like. Among these, 4' - (3,3, 5-trimethylcyclohexylidene) bisphenol and 4,4' - (3,3,5, 5-tetramethylcyclohexylidene) bisphenol are preferable, and 4,4' - (3,3, 5-trimethylcyclohexylidene) bisphenol is more preferable, from the viewpoint of easiness of obtaining and good physical properties of the cured product.

The novolak phenol compound (b2) is represented by said formula (3). Preferably represented by said formula (4).

In the formula (3), A¹Each independently represents an aromatic ring group selected from a benzene ring, a naphthalene ring and a biphenyl ring, and the aromatic ring groups may have a C1-49 hydrocarbon group which may have a hetero atom as a substituent (R)²⁰) The aromatic ring group has at least one substituent (R)¹⁸). The substituent (R)¹⁸) Is any one of an aryl group having 6 to 48 carbon atoms, an aryloxy group having 6 to 48 carbon atoms, an aralkyl group having 7 to 49 carbon atoms, or an aralkyloxy group having 7 to 49 carbon atoms. Substituent (R)¹⁸) The group represented by the formula (4a) is preferably a phenyl group, a naphthyl group, an indanyl group, a 2-phenylethyl group, a naphthylmethyl group, an anthrylmethyl group, a phenoxy group, a naphthyloxy group, a benzyloxy group, or a naphthylmethoxy group, and more preferably a benzyl group or a 1-phenylethyl group. By having a substituent (R)¹⁸) The physical properties of the cured product can be improved.

Constitution A¹Except for the essential substituents (R)¹⁸) In addition, the compound may have other substituents (R)¹⁷). Here, the substituent (R)¹⁸) And a substituent (R)¹⁷) Is understood to be a substituent (R)²⁰) One of (1) and (b). The substituent (a1) has a C1-49 hydrocarbon group which may have a heteroatom and is different from R in C¹The hydrocarbon groups which may have a hetero atom described in (1) are the same. Substituent (R)¹⁸) And R in the formula (4)⁸Corresponding to (R)¹⁷) And R in the formula (4)⁷Correspondingly, but as described below, further to R⁷And R⁸And (4) limiting.

Substituent (R) of these¹⁸) The (C) can be introduced by introducing a substituent (R) such as phenylphenol, cumylphenol, styrenated phenol, benzylphenol, and phenoxyphenol¹⁸) The phenol compound (b) is obtained by converting the phenol compound (b) into a raw material and then converting the raw material into a novolak. In this case, a substituent (R) is contained¹⁸) Of phenols of (a)(R¹⁸) The number of (A) is directly a substituent (R)¹⁸) Average value of the number of (2). In the adjustment of substituent (R)¹⁸) When the number of (A) is plural, the substituents (R) may be used in combination¹⁸) With unsubstituted phenols or containing non-substituents (R)¹⁸) The substituted phenols mentioned above may be used.

Further, by using an aralkylating agent for the novolak phenol compound, a substituent (R) can be introduced¹⁸). In this case, the molar amount of the aralkylating agent used relative to 1 aromatic ring of the novolak phenol compound is a substituent (R)¹⁸) Average value of the number of (2). The addition of the aralkylating agent is preferably 0.1 to 2.5 mol, more preferably 0.5 to 2.0 mol, and still more preferably 1.0 to 1.5 mol, based on 1 aromatic ring of the novolak phenol compound.

As the aralkylating agent, there may be mentioned: phenyl carbinol compound, phenyl methyl halide compound, naphthyl carbinol compound, naphthyl methyl halide compound, and styrene compound. Specifically, there may be mentioned: benzyl chloride, benzyl bromide, benzyl iodide, o-methylbenzyl chloride, m-methylbenzyl chloride, p-ethylbenzyl chloride, p-isopropylbenzyl chloride, p-tert-butylbenzyl chloride, p-phenylbenzyl chloride, 5-chloromethylacenaphthylene, 2-naphthylmethyl chloride, 1-chloromethyl-2-naphthalene and the nuclear substituted isomers thereof, α -methylbenzyl chloride, α -dimethylbenzyl chloride, benzyl methyl ether, o-methylbenzyl methyl ether, m-methylbenzyl methyl ether, p-ethylbenzyl methyl ether and the nuclear substituted isomers thereof, benzyl ethyl ether, benzyl propyl ether, benzyl isobutyl ether, benzyl n-butyl ether, p-methylbenzyl methyl ether and the nuclear substituted isomers thereof, benzyl alcohol, o-methylbenzyl alcohol, m-methylbenzyl alcohol, p-methylbenzyl methyl ether and the nuclear substituted isomers thereof, P-methylbenzyl alcohol, p-ethylbenzyl alcohol, p-isopropylbenzyl alcohol, p-tert-butylbenzyl alcohol, p-phenylbenzyl alcohol, α -naphthylmethanol and nuclear substituted isomers thereof, α -methylbenzyl alcohol, α -dimethylbenzyl alcohol, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α -methylstyrene, β -methylstyrene and the like. The styrene compound may also contain a small amount of other reaction components (e.g., unsaturated bond-containing components such as divinylbenzene, indene, coumarone, benzothiophene, indole, vinylnaphthalene, etc.). These may be used alone or in combination of two or more. Of these, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α -methylstyrene, β -methylstyrene, benzyl chloride, benzyl bromide, or benzyl alcohol is preferable because it has excellent heat resistance and a lower dielectric constant and dielectric loss tangent.

The reaction for introducing these aralkylating agents may be carried out in the presence of an acid catalyst. The acid catalyst can be suitably selected from known inorganic acids and organic acids. For example, there may be mentioned: inorganic acids (mineral acids) such as hydrochloric acid, sulfuric acid and phosphoric acid, organic acids such as formic acid, oxalic acid, trifluoroacetic acid, p-toluenesulfonic acid, dimethyl sulfuric acid and diethyl sulfuric acid, lewis acids such as zinc chloride, aluminum chloride, ferric chloride and boron trifluoride, solid acids such as ion exchange resins, activated clay, silica-alumina and zeolites, and the like.

Further, a phenol novolac compound obtained by the reaction of a bifunctional or higher phenol with a crosslinking group is reacted with the aralkylating agent in the presence of a base catalyst, whereby a part of the hydroxyl groups becomes aralkyloxy groups. Examples of the base catalyst include: alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and inorganic bases such as sodium metal, lithium metal, sodium carbonate and potassium carbonate. The amount of the compound to be used is preferably in the range of 1 to 2 moles based on 1 mole of the aralkylating agent.

Further, a substituent (R)¹⁸) In addition to the above, aryl groups and aryloxy groups may be used, and introduction of these groups is carried out by using an aryl-substituted phenol such as phenylphenol or an aryloxy-substituted phenol such as phenoxyphenol as the raw material phenol.

T is a divalent aliphatic cyclic hydrocarbon group or any of divalent crosslinking groups represented by the formula (3a) or the formula (3 b).

Carbon number of divalent aliphatic Cyclic Hydrocarbon groupPreferably 5 to 15, and more preferably 5 to 10. Specifically, a cycloalkylene group having 5 to 12 carbon atoms or a divalent group including a condensed ring represented by the following structural formula may be mentioned, but the present invention is not limited thereto. In addition, in the case where the cycloalkylene group having 5 to 12 carbon atoms has different carbon atoms or ring members, X is referred to unless a substituent is not required²Description of the cycloalkylene group described in (1).

[ solution 9]

In the formula (3a), R³And R⁴Each independently represents a hydrogen atom or a C1-20 hydrocarbon group which may have a hetero atom, and is preferably a hydrogen atom, an aliphatic hydrocarbon group having 1-20 carbon atoms, an alicyclic hydrocarbon group having 3-20 carbon atoms, or an aromatic hydrocarbon group having 6-20 carbon atoms. In the case where an aromatic ring is present among these substituents, the aromatic ring may have a hydroxyl group as a substituent.

In the formula (3b), R⁵And R⁶Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. A. the²Is an aromatic group containing a benzene ring, a naphthalene ring or a biphenyl ring. Further, constitution A²These rings of (A) may be substituted with¹The same substituents.

k is 1 or 2 and represents the number of hydroxyl groups of the starting phenol. m represents a repetition number of 1 to 20. The average value is 1.5 or more, preferably 1.7 to 10, more preferably 2.0 to 5.0, and still more preferably 2.2 to 4.0.

The novolak phenol compound (b2) is preferably a substituted phenol novolak compound represented by the formula (4). In the formula (4), R⁷Each independently represents a hydrocarbon group having 1 to 6 carbon atoms, preferably a methyl group, a tert-butyl group, a phenyl group, a cyclohexyl group, etc., more preferably a methyl group. R⁸Represents a substituent represented by the formula (4 a). p is an integer of 0 to 3, and the average value is a number of 0.1 to 2.5, preferably 0.5 to 2.0, and more preferably 1.0 to 1.5. q is an integer of 0 to 2, and the average value is a number of 0 to 2, preferably 0 to 1. In addition, p + q is a number of 0.1 to 3 in average value.

In the formula (4a), R⁹、R¹⁰And R¹¹Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms, preferably a hydrogen atom, a methyl group, a tert-butyl group or a phenyl group, and more preferably a hydrogen atom or a methyl group. More preferably R⁹And R¹⁰One is a hydrogen atom and the other is a methyl group. As R⁸Specific examples of (3) include: benzyl, methylbenzyl, ethylbenzyl, isopropylbenzyl, t-butylbenzyl, cyclohexylbenzyl, phenylbenzyl, dimethylbenzyl, 1-phenylethyl, 1-tolylethyl, 1-ditolylethyl, 2-phenylpropan-2-yl, 2-tolylpropan-2-yl, 2-ditolylpropan-2-yl and the like.

The phenol novolac compound represented by the formula (4) is preferably a styrene-modified novolac resin represented by the following formula (7) in which styrene is added to a phenol novolac resin. In the formula (7), p and m are the same as those in the formula (4).

[ solution 10]

The raw material phenols used for obtaining the novolak phenol compound (b2) include: phenol, cresol, ethylphenol, butylphenol, phenylphenol, styrenated phenol, cumylphenol, benzylphenol, phenoxyphenol, naphthol, catechol, resorcinol, naphthalenediol, and the like, but are not limited thereto, and these phenols may be used alone or in combination of two or more. Among these phenols, monophenols such as phenol and alkylphenol are preferable. As the alkyl group in the case of alkylphenol, an alkyl group having 1 to 6 carbon atoms is suitable. In the case of phenylphenol, cumylphenol, styrenated phenol, benzylphenol, phenoxyphenol, or the like, as described above, the compound that has been novolak-converted with a crosslinking agent directly becomes the novolak phenol compound (b 2). In other cases, it is necessary to add a substituent such as an aromatic ring-containing aralkyl group using an aralkylating agent or the like.

As the crosslinking agent which provides T of the formula (3), there may be mentioned: aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde and benzaldehyde, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and acetophenone, diols such as p-xylylene glycol, dialkoxy bases such as p-xylylene glycol dimethyl ether, 4 '-dimethoxymethyl biphenyl and dimethoxymethyl naphthalene, dichloromethyl bases such as p-xylylene dichloride, 4' -dichloromethyl biphenyl and dichloromethyl naphthalene, divinyl bases such as divinylbenzene, divinyl biphenyl and divinyl naphthalene, and cyclic alkadienes (alkadiene) such as cyclopentadiene and dicyclopentadiene, but the crosslinking agents are not limited thereto, and these crosslinking agents may be used alone, or two or more kinds may be used in combination. T in the formula (3) is a divalent aliphatic cyclic hydrocarbon group when a cyclic diene is used, a crosslinking group represented by the formula (3a) when an aldehyde or a ketone is used, or a crosslinking group represented by the formula (3b) when a diol, a dialkoxy group, a bischloromethane group or a divinyl group is used. Among these crosslinking agents, formaldehyde, acetaldehyde, benzaldehyde, acetone, p-xylene dichloride and 4,4' -dichloromethylbiphenyl are preferable, and formaldehyde is particularly preferable. Preferred examples of the form in which formaldehyde is used in the reaction include formalin, p-formaldehyde, trioxane, and the like.

The molar ratio of the phenol to the crosslinking agent is represented by a molar ratio of the phenol to 1 mole of the crosslinking agent (phenol/crosslinking agent), and is produced at a ratio of 0.1 or more, and when the molar ratio is large, a large amount of dinuclears and trinuclears are produced, whereas when the molar ratio is small, a large amount of high molecular weight material of five or more nuclei is produced, and the amount of dinuclears and trinuclears is small. Here, in the novolak phenol compound (b2) represented by the formula (3), the core such as a dinuclear body or a trinuclear body means A present in the molecule¹The number of (2). That is, the i nucleus is a compound having the structural formula of m ═ i-1 in formula (3). The molar ratio of the phenol to the crosslinking agent (phenol/crosslinking agent) is preferably 0.1 to 10, more preferably 0.3 to 6, and still more preferably 0.5 to 4. In addition, by reducing or removing low molecular weight components as necessary, a novolak phenol compound having a narrow molecular weight distribution can also be obtained. In this case, it is preferable that the air conditioner,as a method for reducing or removing low molecular weight components, particularly dinuclear bodies, there can be mentioned: a method utilizing poor solubility of various solvents, a method of dissolving in an alkaline aqueous solution, other known separation methods, and the like.

Examples of the acidic catalyst used for obtaining the novolak phenol compound (b2) include: protonic acids such as hydrochloric acid, phosphoric acid, sulfuric acid, nitric acid and toluenesulfonic acid, lewis acids such as boron trifluoride, aluminum chloride, tin chloride, zinc chloride and ferric chloride, oxalic acid and monochloroacetic acid, but the acidic catalysts are not limited thereto, and these acidic catalysts may be used alone or in combination of two or more. Among these acidic catalysts, phosphoric acid, toluenesulfonic acid and oxalic acid are preferable.

Epoxy resins other than the oxazolidone ring-containing epoxy resin (a) may be used in combination with the epoxy resin (a) in the epoxy resin composition of the present invention within the range that does not impair the physical properties. Epoxy resins other than the oxazolidone ring-containing epoxy resin (a) that can be used in combination are not particularly limited, and polyfunctional epoxy resins containing two or more epoxy groups are preferable. Specifically, there may be mentioned: polyglycidyl ether compounds, polyglycidyl amine compounds, polyglycidyl ester compounds, alicyclic epoxy compounds, other modified epoxy resins, and the like, but are not limited thereto. These epoxy resins may be used alone, or two or more epoxy resins of the same system may be used in combination, or epoxy resins of different systems may be used in combination. In the epoxy resin (a), the amount of the epoxy resin other than the oxazolidone ring-containing epoxy resin (a) is 0 to 95% by mass, preferably 0 to 80% by mass, more preferably 0 to 50% by mass, and still more preferably 0 to 30% by mass.

Specific examples of the polyglycidyl ether compound include: bisphenol A-type epoxy resin, bisphenol F-type epoxy resin, tetramethylbisphenol F-type epoxy resin, biphenol-type epoxy resin, hydroquinone-type epoxy resin, bisphenol fluorene-type epoxy resin, naphthalenediphenol-type epoxy resin, bisphenol S-type epoxy resin, diphenylsulfide-type epoxy resin, diphenyl ether-type epoxy resin, resorcinol-type epoxy resin, phenol novolac-type epoxy resin, cresol novolac-type epoxy resin, alkyl novolac-type epoxy resin, aromatic modified phenol novolac-type epoxy resin, bisphenol novolac-type epoxy resin, naphthol novolac-type epoxy resin, beta-naphthol aralkyl-type epoxy resin, naphthalenediol aralkyl-type epoxy resin, alpha-naphthol aralkyl-type epoxy resin, biphenylaralkyl phenol-type epoxy resin, trihydroxyphenyl methane-type epoxy resin, tetrahydroxyethane-type epoxy resin, Dicyclopentadiene type epoxy resins, alkanediol type epoxy resins, aliphatic cyclic epoxy resins, and the like, but are not limited thereto.

Specific examples of the polyglycidyl amine compound include: diaminodiphenylmethane epoxy resins, m-xylylenediamine epoxy resins, 1, 3-bisaminomethylcyclohexane epoxy resins, isocyanurate epoxy resins, aniline epoxy resins, hydantoin epoxy resins, aminophenol epoxy resins, and the like, but are not limited thereto.

Specific examples of the polyglycidyl ester compound include: dimer acid type epoxy resins, hexahydrophthalic acid type epoxy resins, trimellitic acid type epoxy resins, and the like, but are not limited thereto.

Examples of the alicyclic epoxy compound include, but are not limited to, aliphatic cyclic epoxy resins such as siroxde 2021 (manufactured by cellosolve chemical industries, ltd.).

Specific examples of the other modified epoxy resin include: urethane-modified epoxy resin, (a) epoxy resin containing oxazolidone ring other than the skeleton, epoxy-modified polybutadiene rubber derivative, CTBN-modified epoxy resin, polyvinylarene polyoxide (e.g., divinylbenzene dioxide, trivinylnaphthalene trioxide), phosphorus-containing epoxy resin, and the like, but are not limited thereto.

The curing agent (B) in the epoxy resin composition of the present invention may be used together with a curing agent other than the bisphenol compound (B1) and the novolak phenol compound (B2) within the range that does not impair the physical properties. The curing agents other than (b1) and (b2) that can be used in combination are not particularly limited as long as they are curing epoxy resins, and phenolic curing agents, acid anhydride curing agents, amine curing agents, hydrazide curing agents, active ester curing agents, phosphorus curing agents, and other curing agents for epoxy resins can be used. These curing agents may be used alone, or two or more of the same system of curing agents may be used in combination, or curing agents of different systems may be used in combination. The amount of the curing agent (B) other than (B1) and (B2) used in the curing agent (B) is 0 to 95% by mass, preferably 0 to 80% by mass, more preferably 0 to 50% by mass, and still more preferably 0 to 30% by mass.

The phenolic hardener is particularly preferably one containing a large amount of aromatic skeleton in the molecular structure, and examples thereof include: phenol novolac resins, cresol novolac resins, aromatic hydrocarbon formaldehyde resin-modified phenol resins, phenol aralkyl resins, naphthol novolac resins, naphthol-phenol co-condensed novolac resins, naphthol-cresol co-condensed novolac resins, biphenyl-modified phenol resins, biphenyl-modified naphthol resins, and aminotriazine-modified phenol resins. The same as the formula (3) in these is regarded as (b2), and therefore is preferably an unsubstituted body, an alkyl substituted body, a cycloalkyl substituted body, or an alkoxy substituted body.

Further, a benzoxazine compound which is ring-opened to a phenol compound upon heating is also useful as a curing agent. Specifically, a bisphenol F type or bisphenol S type benzoxazine compound may be mentioned, but the invention is not limited thereto.

Specific examples of the acid anhydride-based curing agent include: tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, phthalic anhydride, trimellitic anhydride, hydrogenated trimellitic anhydride, methylnadic anhydride, succinic anhydride, maleic anhydride, etc., or 4,4 '-oxydiphthalic anhydride, 4' -diphthalic anhydride, pyromellitic anhydride, hydrogenated pyromellitic anhydride, 1,2,3, 4-cyclobutanetetracarboxylic dianhydride, 1,2,3, 4-cyclopentanetetracarboxylic dianhydride, 5- (2, 5-dioxotetrahydrofurfuryl) -3-methyl-3-cyclohexene-1, 2-dicarboxylic anhydride, 4- (2, 5-dioxotetrahydrofurn-3-yl) -1,2,3, 4-tetrahydronaphthalene-1, 2-dicarboxylic anhydride, but is not limited thereto.

Examples of the amine-based curing agent include amine compounds which can be used as the various epoxy resin modifiers. In addition, there may be mentioned, but not limited to, 2,4, 6-tris (dimethylaminomethyl) phenol, dimer diamine, dicyan diamine and derivatives thereof, and amine compounds such as polyamide amine which is a condensate of polyamines and acids such as dimer acid.

Specific examples of the hydrazide-based curing agent include: adipic acid dihydrazide, isophthalic acid dihydrazide, sebacic acid dihydrazide, dodecane diacid dihydrazide, and the like, but are not limited thereto.

Examples of the active ester-based curing agent include reaction products of polyfunctional phenol compounds and aromatic carboxylic acids as described in Japanese patent No. 5152445, and commercially available products include Epiclon HPC-8000-65T (manufactured by Diesen der Ltd.), but are not limited thereto.

The ratio of the epoxy resin (a) to the curing agent (B) is preferably 0.2 to 1.5 moles of active hydrogen groups of the curing agent (B) relative to 1 mole of epoxy groups of the epoxy resin (a). If the active hydrogen group is less than 0.2 mol or more than 1.5 mol based on 1 mol of the epoxy group, curing may be incomplete and good curing properties may not be obtained. The preferable range is 0.3 to 1.5 moles, the more preferable range is 0.5 to 1.5 moles, and the further preferable range is 0.8 to 1.2 moles. The total amount of phenolic hydroxyl groups of the bisphenol compound (b1) and the novolac phenol compound (b2) is preferably 0.8 to 1.2 moles, more preferably 0.9 to 1.1 moles, and even more preferably 0.95 to 1.05 moles, based on 1 mole of epoxy groups of the oxazolidone ring-containing epoxy resin (a) or the reaction product (a2) comprising the oxazolidone ring-containing epoxy resin (a) and a by-product or the like. In the case where an epoxy resin other than the oxazolidone ring-containing epoxy resin (a) or the reaction product (a2), or a curing agent other than the bisphenol compound (b1) and the novolak phenol compound (b2) is used in combination in the epoxy resin composition, the amount of blending is preferably determined in consideration of the most preferable blending amount of the epoxy resin or the curing agent used in combination. For example, when a phenol-based curing agent, an amine-based curing agent, or an active ester-based curing agent is used in combination, active hydrogen groups are prepared in an approximately equimolar amount with respect to epoxy groups, and when an acid anhydride-based curing agent is used, acid anhydride groups are prepared in an amount of 0.5 to 1.2 moles, preferably 0.6 to 1.0 mole, with respect to 1 mole of epoxy groups.

The active hydrogen group in the present specification is a functional group having an active hydrogen reactive with an epoxy group (including a functional group having a latent active hydrogen which generates an active hydrogen by hydrolysis or the like, or a functional group which exhibits a similar curing action), and specifically includes an acid anhydride group, a carboxyl group, an amino group, a phenolic hydroxyl group, or the like. Further, as for the active hydrogen group, a carboxyl group (-COOH) or a phenolic hydroxyl group (-OH) is calculated as 1 mol, and an amino group (-NH)₂) Calculated as 2 moles. In the case where the active hydrogen group is not clear, the active hydrogen equivalent can be determined by measurement. For example, the active hydrogen equivalent of the curing agent used can be determined by reacting a monoepoxy resin having a known epoxy equivalent such as phenyl glycidyl ether with a curing agent having an unknown active hydrogen equivalent, and measuring the amount of the monoepoxy resin consumed.

In the epoxy resin composition of the present invention, a hardening accelerator may be used as needed. Examples of the hardening accelerator include: examples of the metal salt include, but are not limited to, imidazole derivatives, tertiary amines, phosphorus compounds such as phosphines, metal compounds, lewis acids, and amine complex salts (amine complex salts). These hardening accelerators may be used alone or in combination of two or more.

The imidazole derivative is not particularly limited as long as it is a compound having an imidazole skeleton. Examples thereof include: an alkyl-substituted imidazole compound such as 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, bis-2-ethyl-4-methylimidazole, 1-methyl-2-ethylimidazole, 2-isopropylimidazole, 2, 4-dimethylimidazole, 2-heptadecylimidazole or an alkyl-substituted imidazole compound such as 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-ethylimidazole, 1-benzyl-2-phenylimidazole, benzimidazole, 2-ethyl-4-methyl-1- (2' -cyanoethyl) imidazole, 2, 3-dihydro-1H-pyrrolo [1, and imidazole compounds substituted with a hydrocarbon group having a ring structure such as an aryl group or an aralkyl group, such as 2-a benzimidazole, but the present invention is not limited thereto.

Examples of tertiary amines include: 2-dimethylaminopyridine, 4-dimethylaminopyridine, 2- (dimethylaminomethyl) phenol, 1,8-diaza-bicyclo [5.4.0] -7-undecene (1,8-diaza-bicyclo [5.4.0] -7-undecene, DBU) and the like, but are not limited thereto.

Examples of phosphines include: triphenylphosphine, tricyclohexylphosphine, triphenylphosphine triphenylborane, and the like, but are not limited thereto.

Examples of the metal compound include, but are not limited to, tin octylate and the like.

Examples of the amine complex salt include: boron trifluoride monoethylamine complex, boron trifluoride diethylamine complex, boron trifluoride isopropylamine complex, boron trifluoride chlorophenylamine complex, boron trifluoride benzylamine complex, boron trifluoride aniline complex, or a mixture of these complexes, and the like, but is not limited thereto.

Among these hardening accelerators, 2-dimethylaminopyridine, 4-dimethylaminopyridine and imidazoles are preferable from the viewpoint of excellent heat resistance, dielectric properties, solder resistance and the like when used for a build-up material or a circuit board. When used as a semiconductor sealing material, triphenylphosphine or DBU is preferable in terms of excellent curing properties, heat resistance, electrical characteristics, moisture resistance reliability, and the like.

The amount of the curing accelerator to be blended may be appropriately selected depending on the purpose of use, and is 0.01 to 15 parts by mass as necessary per 100 parts by mass of the epoxy resin component in the epoxy resin composition. Preferably 0.01 to 10 parts by mass, more preferably 0.05 to 8 parts by mass, and still more preferably 0.1 to 5 parts by mass. By using a hardening accelerator, the hardening temperature can be lowered, or the hardening time can be shortened.

Organic solvents or reactive diluents can be used in the epoxy resin composition for adjusting the viscosity.

Examples of the organic solvent include: amides such as N, N-dimethylformamide and N, N-dimethylacetamide, ethers such as ethylene glycol monomethyl ether, dimethoxydiethylene glycol, ethylene glycol diethyl ether, diethylene glycol diethyl ether and triethylene glycol dimethyl ether, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, alcohols such as methanol, ethanol, 1-methoxy-2-propanol, 2-ethyl-1-hexanol, benzyl alcohol, ethylene glycol, propylene glycol, butyl diethylene glycol and pine oil, acetates such as butyl acetate, methoxybutyl acetate, methyl cellosolve acetate, ethyl diethylene glycol acetate, propylene glycol monomethyl ether acetate, carbitol acetate and benzyl alcohol acetate, benzoates such as methyl benzoate and ethyl benzoate, methyl cellosolve, etc, Cellosolves such as butyl cellosolve, carbitols such as methyl carbitol, carbitol and butyl carbitol, aromatic hydrocarbons such as benzene, toluene and xylene, dimethyl sulfoxide, acetonitrile and N-methylpyrrolidone, but the present invention is not limited thereto.

Examples of the reactive diluent include: monofunctional glycidyl ethers such as allyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, and cresyl glycidyl ether, or difunctional glycidyl ethers such as resorcinol diglycidyl ether, neopentyl glycol diglycidyl ether, 1, 4-butanediol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, and propylene glycol diglycidyl ether, or polyfunctional glycidyl ethers such as glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, trimethylolethane polyglycidyl ether, pentaerythritol polyglycidyl ether and the like, or glycidyl esters such as glycidyl neodecanoate, or glycidyl amines such as phenyl diglycidyl amine and tolyl diglycidyl amine, but the present invention is not limited thereto.

These organic solvents and reactive diluents are preferably used alone or in a mixture of two or more thereof in an amount of 90% by mass or less of nonvolatile components, and the appropriate type and amount of use may be selected as appropriate depending on the application. For example, in the case of use in a printed wiring board, a polar solvent having a boiling point of 160 ℃ or lower such as methyl ethyl ketone, acetone, or 1-methoxy-2-propanol is preferable, and the amount used is preferably 40 to 80% by mass in terms of nonvolatile components. In addition, for the adhesive film, for example, ketones, acetates, carbitols, aromatic hydrocarbons, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, and the like are preferably used, and the amount thereof is preferably 30 to 60% by mass in terms of nonvolatile components.

In the epoxy resin composition, various flame retardants conventionally known can be used in order to improve the flame retardancy of the cured product obtained without lowering the reliability. Examples of flame retardants that can be used include: halogen flame retardants, phosphorus flame retardants (phosphorus compounds as flame retardants), nitrogen flame retardants, silicone flame retardants, inorganic flame retardants, and organic metal salt flame retardants. From the viewpoint of environment, a halogen-free flame retardant is preferable, and a phosphorus-based flame retardant is particularly preferable. These flame retardants are not particularly limited in use, and may be used alone, or a plurality of flame retardants of the same system may be used, or flame retardants of different systems may be used in combination.

The phosphorus-containing additive may be either an inorganic phosphorus compound or an organic phosphorus compound. Examples of the inorganic phosphorus-based compound include: ammonium phosphates such as red phosphorus, monoammonium phosphate, diammonium phosphate, triammonium phosphate and ammonium polyphosphate, and nitrogen-containing inorganic phosphorus compounds such as phosphoramide, but the present invention is not limited thereto.

Examples of the organic phosphorus-based compound include general-purpose organic phosphorus-based compounds such as phosphate compounds, condensed phosphate esters, phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, and phosphorane compounds, nitrogen-containing organic phosphorus-based compounds, and metal phosphinates, and in addition: phosphorus compounds having an active hydrogen group directly bonded to a phosphorus atom (e.g., 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, diphenylphosphine oxide, etc.) or phosphorus-containing phenol compounds (e.g., 10- (2, 5-dihydroxyphenyl) -10H-9-oxa-10-phosphaphenanthrene-10-oxide, 10- (2, 7-dihydroxynaphthyl) -10H-9-oxa-10-phosphaphenanthrene-10-oxide, diphenylphosphino hydroquinone, diphenylphosphino-1, 4-dioxynaphthalene, 1, 4-cyclooctylenephosphinyl-1, 4-phenylenediol, 1, 5-cyclooctylenephosphinyl-1, 4-phenyl diol), or the like), or derivatives thereof obtained by reacting these organophosphorus compounds with compounds such as epoxy resins or phenol resins, but the present invention is not limited to these.

Examples of the phosphorus-containing epoxy resin that can be used in combination include: and FX-305 and FX-289B, TX-1320A, TX-1328 (manufactured by Nissian iron-on-Steel chemical Co., Ltd.) by Epotohto, but the present invention is not limited thereto. The epoxy equivalent of the phosphorus-containing epoxy resin that can be used in combination is preferably 200 to 800, more preferably 300 to 780, and even more preferably 400 to 760. The phosphorus content is preferably 0.5 to 6% by mass, more preferably 2 to 5.5% by mass, and still more preferably 3 to 5% by mass. In addition to the phosphorus-containing phenol compound, a phosphorus-containing phenol compound can be obtained by reacting a phosphorus compound with an aldehyde and a phenol compound by a production method as shown in Japanese patent laid-open No. 2008-501063 or Japanese patent No. 4548547. Further, an aromatic carboxylic acid can be reacted by a production method shown in Japanese patent laid-open publication No. 2013-185002 to obtain a phosphorus-containing active ester compound from a phosphorus-containing phenol compound. Further, a phosphorus-containing benzoxazine compound can be obtained by a production method as shown in WO 2008/010429.

The amount of the phosphorus compound to be used in combination can be suitably selected depending on the kind of the phosphorus compound, the phosphorus content, the components of the epoxy resin composition, and the desired degree of flame retardancy. When the phosphorus compound is a reactive phosphorus compound, that is, a phosphorus-containing epoxy resin or a phosphorus-containing curing agent, the phosphorus content is preferably 0.2 to 6% by mass, more preferably 0.4 to 4% by mass, even more preferably 0.5 to 3.5% by mass, and even more preferably 0.6 to 3% by mass, based on the solid content (nonvolatile content) in the entire epoxy resin composition in which the epoxy resin, the curing agent for epoxy resin, the flame retardant, and other fillers or additives are blended. If the phosphorus content is low, it may be difficult to ensure flame retardancy, and if the phosphorus content is too high, it may adversely affect heat resistance. When the phosphorus compound is an additive phosphorus flame retardant, it is preferably blended in a range of 0.1 to 2 parts by mass when red phosphorus is used, and it is also preferably blended in a range of 0.1 to 10 parts by mass, particularly preferably blended in a range of 0.5 to 6 parts by mass when an organic phosphorus compound is used, to 100 parts by mass of a solid component (nonvolatile component) in the epoxy resin composition.

When a phosphorus compound is used as the flame retardant, hydrotalcite, magnesium hydroxide, a boron compound, zirconium oxide, calcium carbonate, zinc molybdate, or the like may be used as the flame retardant aid in combination.

In the present invention, a phosphorus compound is preferably used as the flame retardant, but the following flame retardants may be used.

Examples of the nitrogen-based flame retardant include: triazine compounds, cyanuric acid compounds, isocyanuric acid compounds, phenothiazine and the like, and preferably triazine compounds, cyanuric acid compounds, isocyanuric acid compounds. The amount of the nitrogen-based flame retardant to be blended may be appropriately selected depending on the kind of the nitrogen-based flame retardant, other components of the epoxy resin composition, and the desired degree of flame retardancy, and for example, the amount of the nitrogen-based flame retardant to be blended is preferably in the range of 0.05 to 10 parts by mass, and particularly preferably in the range of 0.1 to 5 parts by mass, based on 100 parts by mass of the solid content (nonvolatile content) in the epoxy resin composition. When a nitrogen-based flame retardant is used, a metal hydroxide, a molybdenum compound, or the like may be used in combination.

The silicone flame retardant is not particularly limited as long as it is an organic compound containing a silicon atom, and examples thereof include: silicone oil, silicone rubber, silicone resin, and the like, but are not limited thereto. The amount of the silicone flame retardant to be blended may be appropriately selected depending on the type of the silicone flame retardant, other components of the epoxy resin composition, and the desired degree of flame retardancy, and is preferably in the range of 0.05 to 20 parts by mass, for example, based on 100 parts by mass of the solid content (nonvolatile content) in the epoxy resin composition. When a silicone flame retardant is used, a molybdenum compound, alumina, or the like may be used in combination.

Examples of the inorganic flame retardant include: metal hydroxides, metal oxides, metal carbonate compounds, metal powders, boron compounds, low melting point glasses, and the like, but are not limited thereto. The amount of the inorganic flame retardant to be blended may be appropriately selected depending on the kind of the inorganic flame retardant, other components of the epoxy resin composition, and the desired degree of flame retardancy, and for example, it is preferably blended in the range of 0.05 to 20 parts by mass, and particularly preferably in the range of 0.5 to 15 parts by mass, based on 100 parts by mass of the solid content (nonvolatile content) in the entire epoxy resin composition in which the epoxy resin, the curing agent for epoxy resin, the flame retardant, and other fillers or additives are blended.

Examples of the organic metal salt-based flame retardant include: ferrocene, acetylacetone metal complexes, organometallic carbonyl compounds, organic cobalt salt compounds, organic sulfonic acid metal salts, compounds in which a metal atom is ionically or coordinately bonded to an aromatic compound or a heterocyclic compound, and the like, but the invention is not limited thereto. The amount of the organic metal salt-based flame retardant to be blended may be appropriately selected depending on the kind of the organic metal salt-based flame retardant, other components of the epoxy resin composition, and the desired degree of flame retardancy, and is preferably in the range of 0.005 to 10 parts by mass, for example, based on 100 parts by mass of the solid content (nonvolatile content) of the epoxy resin composition in which the epoxy resin, the curing agent for epoxy resin, the flame retardant, and other fillers or additives are blended.

In the epoxy resin composition, if necessary, other additives such as a filler, a thermoplastic resin, or a thermosetting resin other than the epoxy resin, a silane coupling agent, an antioxidant, a release agent, an antifoaming agent, an emulsifier, a thixotropy imparting agent, a lubricant, and a pigment may be blended within a range where the properties are not impaired.

Examples of the filler include: fused silica, crystalline silica, alumina, silicon nitride, boron nitride, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, boehmite, talc, mica, clay, calcium carbonate, magnesium carbonate, barium carbonate, zinc oxide, titanium oxide, magnesium silicate, calcium silicate, zirconium silicate, barium sulfate, carbon and other inorganic fillers, carbon fibers, glass fibers, alumina fibers, aluminosilicate fibers, silicon carbide fibers, polyester fibers, cellulose fibers, aramid fibers, ceramic fibers and other fibrous fillers, and particulate rubbers. Among these fillers, those which are not decomposed or dissolved by an acidic compound such as an aqueous solution of permanganate used for the surface roughening treatment of the cured product are preferable, and particularly, fused silica or crystalline silica is preferable because fine particles are easily obtained. When the amount of the filler to be blended is particularly large, fused silica is preferably used. Either of the crushed form and the spherical form of the fused silica can be used, and in order to increase the amount of the fused silica to be blended and thereby suppress an increase in the melt viscosity of the molding material, it is more preferable to mainly use the spherical fused silica. Further, in order to increase the amount of the spherical silica, it is preferable to appropriately adjust the particle size distribution of the spherical silica. The filler may be treated with a silane coupling agent or treated with an organic acid such as stearic acid. The reason why the filler is generally used is that the impact resistance of the cured product is improved or the linear expansion of the cured product is reduced. In addition, when a metal hydroxide such as aluminum hydroxide, boehmite, or magnesium hydroxide is used, it has an effect of acting as a flame retardant aid to improve flame retardancy. When used for applications such as conductive paste, a conductive filler such as silver powder or copper powder can be used.

When the low linear expansion property or the flame retardancy of the cured product is taken into consideration, the amount of the filler to be blended is preferably high. The amount of the epoxy resin composition is preferably 1 to 90% by mass, more preferably 5 to 80% by mass, and still more preferably 10 to 60% by mass, based on the solid content (nonvolatile content) in the epoxy resin composition. If the blending amount is large, the adhesiveness required for the use as a laminate may be lowered, and further, the cured product may become brittle, and sufficient mechanical properties may not be obtained. In addition, if the blending amount is small, there is a concern that: the impact resistance of the cured product is improved, and the effect of blending the filler is not considered.

The average particle diameter of the inorganic filler is preferably 0.05 to 1.5. mu.m, more preferably 0.1 to 1 μm. When the average particle diameter of the inorganic filler is within this range, the fluidity of the epoxy resin composition is favorably maintained. The average particle diameter can be measured by a particle size distribution measuring apparatus.

The blending of the thermoplastic resin is particularly effective in the case of molding the epoxy resin composition into a sheet or film form. Examples of the thermoplastic resin include: phenoxy resins, polyurethane resins, polyester resins, polyethylene resins, polypropylene resins, polystyrene resins, ABS resins, AS resins, vinyl chloride resins, polyvinyl acetate resins, polymethyl methacrylate resins, polycarbonate resins, polyacetal resins, cyclic polyolefin resins, polyamide resins, thermoplastic polyimide resins, polyamideimide resins, polytetrafluoroethylene resins, polyetherimide resins, polyphenylene ether resins, modified polyphenylene ether resins, polyether sulfone resins, polysulfone resins, polyether ether ketone resins, polyphenylene sulfide resins, polyethylene formaldehyde resins, and the like, but are not limited thereto. The phenoxy resin is preferable in terms of compatibility with the epoxy resin, and the polyphenylene ether resin or the modified polyphenylene ether resin is preferable in terms of low dielectric characteristics.

Examples of other additives include: thermosetting resins other than epoxy resins such as phenol resins, melamine resins, urea resins, unsaturated polyester resins, alkyd resins, diallyl phthalate resins, and thermosetting polyimides, organic pigments such as quinacridone, azo, and phthalocyanine pigments, inorganic pigments such as titanium oxide, metal foil pigments, and rust preventive pigments, ultraviolet absorbers such as hindered amine, benzotriazole, and benzophenone pigments, antioxidants such as hindered phenol, phosphorus, sulfur, and hydrazide antioxidants, coupling agents such as silane and titanium, release agents such as stearic acid, palmitic acid, zinc stearate, and calcium stearate, and additives such as leveling agents, rheology control agents, pigment dispersants, shrinkage inhibitors, and antifoaming agents. The blending amount of these other additives is preferably in the range of 0.01 to 20% by mass relative to the solid content (nonvolatile content) in the epoxy resin composition.

The epoxy resin composition of the present invention can be obtained by uniformly mixing the above-mentioned respective components. The cured product of the present invention can be easily obtained by curing by a method similar to a conventionally known method. As a method for obtaining a cured product, the same method as a known epoxy resin composition can be used, and it is preferable to use: casting, pouring, dipping, drop coating, transfer molding, compression molding, or the like, or a method of forming a laminate by laminating a resin sheet, a resin-coated copper foil, a prepreg, or the like, and then heating and pressure-curing the laminate. The curing temperature in this case is usually in the range of 100 to 300 ℃ and the curing time is usually about 10 minutes to 5 hours. Examples of the cured product include: and molded and cured products such as laminates, castings, molded products, adhesive layers, insulating layers, and films.

Examples of the use of the epoxy resin composition include: a material for circuit boards, a sealing material, a potting material, a conductive paste, an adhesive, or the like. Examples of the material for the circuit board include: prepregs, resin sheets, resin-coated metal foils, insulating materials for circuit boards such as resin compositions for printed wiring boards and flexible wiring boards, interlayer insulating materials for build-up boards, adhesive films for build-up, resist inks, and the like. Among these various applications, printed wiring board materials, insulating materials for circuit boards, and adhesive films for build-up layers are used as insulating materials for boards for embedding so-called electronic components, in which passive components such as capacitors or active components such as Integrated Circuit (IC) chips are embedded in boards. Among these applications, the resin composition is preferably used for a material for a circuit board (laminate) such as a printed wiring board material, a resin composition for a flexible wiring board, an interlayer insulating material for a build-up board, and a semiconductor sealing material, in view of characteristics such as high flame retardancy, high heat resistance, low dielectric characteristics, and solvent solubility.

When the epoxy resin composition is formed into a sheet such as a laminate, the filler used is preferably a fibrous filler, more preferably a glass cloth, a glass fiber mat or a glass scrim, in terms of dimensional stability, bending strength and the like.

The prepreg used for a printed wiring board or the like can be produced by impregnating a fibrous reinforcing base material with the epoxy resin composition. As the fibrous reinforcing base material, woven or nonwoven fabrics of inorganic fibers such as glass, or organic fibers such as polyester resins, polyamine resins, polyacrylic resins, polyimide resins, and aromatic polyamide resins can be used, but the fibrous reinforcing base material is not limited thereto.

The method for producing the prepreg from the epoxy resin composition is not particularly limited, and can be obtained, for example, by: the varnish-like epoxy resin composition containing the organic solvent is prepared into a resin varnish which is further prepared with an organic solvent and adjusted to an appropriate viscosity, and the fibrous base material is impregnated with the resin varnish, and then heated and dried to half-cure (B-stage) the resin component. The heating temperature is preferably 50 to 200 ℃ and more preferably 100 to 170 ℃ depending on the type of the organic solvent used. The heating time is adjusted depending on the kind of the organic solvent used and the curability of the prepreg, and is preferably 1 to 40 minutes, and more preferably 3 to 20 minutes. In this case, the mass ratio of the epoxy resin composition to be used to the reinforcing base material is not particularly limited, and is preferably adjusted so that the resin component in the prepreg is 20 to 80 mass%.

The epoxy resin composition of the present invention can be used in the form of a sheet or a film. In this case, the sheet or film can be formed by a conventionally known method. The method for producing the resin sheet is not particularly limited, and can be obtained, for example, by: the resin varnish is applied to a supporting base film that is not dissolved in the resin varnish by using a coater such as a reverse roll coater, a comma coater, or a die coater, and then heated and dried to form a resin component in a B-stage form. Further, if necessary, another supporting base film is stacked on the coated surface (adhesive layer) as a protective film, and dried, thereby obtaining an adhesive sheet having release layers on both surfaces of the adhesive layer.

As the supporting base film, there can be mentioned: metal foils such as copper foils, polyolefin films such as polyethylene films and polypropylene films, polyester films such as polyethylene terephthalate films, polycarbonate films, silicone films, polyimide films, and the like, and among these support base films, polyethylene terephthalate films which are excellent in dimensional accuracy without defects such as chipping and also excellent in cost are preferred. Further, a metal foil, particularly a copper foil, which facilitates multilayering of the laminate is preferable. The thickness of the support base film is not particularly limited, but is preferably 10 μm to 150 μm, and more preferably 25 μm to 50 μm, in terms of having strength as a support and being less likely to cause lamination failure.

The thickness of the protective film is not particularly limited, but is generally 5 μm to 50 μm. In order to facilitate peeling of the formed adhesive sheet, it is preferable to perform surface treatment with a release agent in advance. The thickness of the coating resin varnish is preferably 5 to 200 μm, more preferably 5 to 100 μm, in terms of the thickness after drying. The heating temperature is preferably 50 to 200 ℃ and more preferably 100 to 170 ℃ depending on the type of the organic solvent used. The heating time is adjusted depending on the kind of the organic solvent used and the curability of the prepreg, and is preferably 1 to 40 minutes, and more preferably 3 to 20 minutes.

The resin sheet obtained in the above manner is usually an insulating adhesive sheet having insulating properties, but a conductive adhesive sheet may be obtained by mixing a conductive metal or metal-coated fine particles with an epoxy resin composition. The supporting base film is laminated on a circuit board, or is heated and cured to form an insulating layer, and then peeled off. If the supporting base film is peeled off after the adhesive sheet is heat-cured, adhesion of dust or the like in the curing step can be prevented. Here, the insulating adhesive sheet is also an insulating sheet.

A metal foil with resin obtained by using the epoxy resin composition will be described. As the metal foil, a single, alloy, or composite metal foil of copper, aluminum, brass, nickel, or the like can be used. Preferably, a metal foil having a thickness of 9 to 70 μm is used. The method for producing a resin-carrying metal foil from a flame-retardant resin composition containing a phosphorus-containing epoxy resin and a metal foil is not particularly limited, and can be obtained, for example, by: a resin varnish prepared by adjusting the viscosity of an epoxy resin composition with a solvent is applied to one surface of the metal foil using a roll coater or the like, and then heated and dried to half-cure (B-stage) the resin component to form a resin layer. When the resin component is half-cured, it may be dried by heating at 100 to 200 ℃ for 1 to 40 minutes, for example. Here, it is preferable that the thickness of the resin portion of the resin-attached metal foil is 5 μm to 110 μm.

In the case of curing the prepreg or the insulating adhesive sheet, a method of curing a laminate in the production of a printed wiring board is generally used, but the present invention is not limited thereto. For example, when a laminate is formed using prepregs, a laminate is obtained by laminating one or more prepregs, disposing metal foils on one side or both sides to form a laminate, and curing and integrating the prepregs by heating the laminate under pressure. Here, as the metal foil, a single, alloy, or composite metal foil of copper, aluminum, brass, nickel, or the like can be used.

The conditions for heating and pressing the laminate may be adjusted as appropriate under the conditions for curing the epoxy resin composition, but if the pressing amount is too low, bubbles may remain in the interior of the obtained laminate, and the electrical characteristics may be degraded, and therefore, it is desirable to apply the pressure under conditions that satisfy moldability. The heating temperature is preferably 160 ℃ to 250 ℃, more preferably 170 ℃ to 220 ℃. The pressurizing pressure is preferably 0.5MPa to 10MPa, more preferably 1MPa to 5 MPa. The heating and pressurizing time is preferably 10 minutes to 4 hours, and more preferably 40 minutes to 3 hours. If the heating temperature is low, the curing reaction may not be sufficiently performed, and if the heating temperature is high, thermal decomposition of the cured product may occur. If the pressing pressure is low, air bubbles may remain in the obtained laminated sheet, and the electrical characteristics may be degraded, and if the pressing pressure is high, the resin flows before curing, and a laminated sheet having a desired thickness may not be obtained. Further, if the heating and pressurizing time is short, the curing reaction may not be sufficiently performed, and if the heating and pressurizing time is long, the thermal decomposition of the cured product may be caused.

Further, a multilayer board can be produced using the single-layer laminated board obtained in the above manner as an inner layer material. In this case, first, a circuit is formed on the laminate by an additive method, a subtractive method, or the like, and the surface of the formed circuit is treated with an acid solution to perform a blackening treatment, thereby obtaining an inner layer material. On one or both circuit-formed surfaces of the inner layer, an insulating layer is formed using a prepreg, a resin sheet, an insulating adhesive sheet, or a metal foil with resin, and a conductor layer is formed on the surface of the insulating layer, thereby forming a multilayer board.

In the case of forming the insulating layer using a prepreg, one or a plurality of prepregs are arranged on the circuit forming surface of the inner layer material, and a metal foil is arranged on the outer side of the prepreg to form a laminate. The laminate is heated and pressed to be integrally molded, whereby a cured prepreg is formed as an insulating layer and a metal foil on the outside is formed as a conductor layer. Here, as the metal foil, the same metal foil as used in the laminate used as the inner layer material can be used. The heat and pressure molding may be performed under the same conditions as the molding of the inner layer material. The surface of the multilayer laminated board formed in the above manner is subjected to formation of via holes or formation of circuits by an additive method or a subtractive method, whereby a printed wiring board can be formed. Further, by repeating the above-mentioned working method using the printed wiring board as an inner layer material, a multilayer board having a plurality of layers can be further formed.

For example, in the case of forming the insulating layer by using an insulating adhesive sheet, the insulating adhesive sheet is disposed on the circuit-formed surface of the plurality of inner layers to form a laminate. Or an insulating adhesive sheet is arranged between the circuit forming surface of the inner layer material and the metal foil to form a laminate. The laminate is heated and pressed to be integrally molded, thereby forming a cured product of the insulating adhesive sheet as an insulating layer and forming a multilayer inner layer material. Alternatively, a hardened material of an insulating adhesive sheet is formed between the inner layer material and the metal foil as the conductor layer to form an insulating layer. Here, as the metal foil, the same metal foil as used in the laminate used as the inner layer material can be used. The heat and pressure molding may be performed under the same conditions as the molding of the inner layer material.

When the epoxy resin composition is applied to the laminate to form the insulating layer, the epoxy resin composition is applied to a thickness of preferably 5 to 100 μm, and then heated and dried at 100 to 200 ℃, preferably 150 to 200 ℃ for 1 to 120 minutes, preferably 30 to 90 minutes to form a sheet. Generally by a method known as casting. The thickness after drying is preferably 5 to 150 μm, preferably 5 to 80 μm. The viscosity of the epoxy resin composition is preferably in the range of 10 to 40000 mPas at 25 ℃, and more preferably in the range of 200 to 30000 mPas, in order to obtain a sufficient film thickness and to prevent uneven coating or streaks. A printed wiring board can be formed by forming a via hole or forming a circuit on the surface of the multilayer laminated board formed in the above manner by an additive method or a subtractive method. Further, by repeating the above-described working method using the printed wiring board as an inner layer material, a multilayer laminated board can be further formed.

The sealing material obtained by using the epoxy resin composition of the present invention is preferably used for a tape-shaped semiconductor chip, a potting liquid sealing, an underfill, a semiconductor interlayer insulating film, and the like. For example, the following methods can be used for molding a semiconductor package: the epoxy resin composition is cast or molded by using a transfer molding machine, an injection molding machine or the like, and further heated at 50 to 200 ℃ for 2 to 10 hours to obtain a molded article.

For preparing the epoxy resin composition for a semiconductor sealing material, the following methods are exemplified: the epoxy resin composition is mixed with a compounding agent such as an inorganic filler, or additives such as a coupling agent and a release agent, which are blended as necessary, and then sufficiently melted and mixed by using an extruder, a kneader, a roll, or the like until the mixture becomes uniform. In this case, it is preferable to mix the inorganic filler in the epoxy resin composition in a proportion of 70 to 95 mass%.

In the case where the epoxy resin composition obtained in the above manner is used as a tape-shaped sealant, the following methods can be cited: heating the semiconductor wafer to form a semi-cured sheet, forming a sealant tape, placing the sealant tape on a semiconductor chip, heating to 100-150 deg.C to soften the semiconductor chip for molding, and completely curing the semiconductor chip at 170-250 deg.C. When the epoxy resin composition is used as a potting liquid sealant, the epoxy resin composition may be dissolved in a solvent as necessary, applied to a semiconductor chip or an electronic component, and cured as it is.

In addition, the epoxy resin composition of the present invention can also be further used as a resist ink. In this case, the following methods can be cited: a resist ink composition is prepared by blending an epoxy resin composition with a vinyl monomer having an ethylenically unsaturated double bond, a cationic polymerization catalyst as a curing agent, and further adding a pigment, talc, and a filler, and then coated on a printed circuit board by a screen printing method to prepare a cured resist ink. The curing temperature in this case is preferably in a temperature range of about 20 ℃ to 250 ℃.

The epoxy resin composition of the present invention is prepared and cured by heat curing to evaluate the cured product, and as a result, a cured product exhibiting low dielectric characteristics which have not been achieved and having an excellent balance of heat resistance, adhesion, and the like can be obtained. Further, flame retardancy can be imparted to the resin composition without deteriorating heat resistance, adhesiveness, and the like while exhibiting low dielectric characteristics by blending a flame retardant.

[ examples ]

The present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited to these examples as long as the invention does not depart from the gist thereof. Unless otherwise specified, parts represent parts by mass and% represents% by mass.

The analysis method and the measurement method are shown below.

(1) Epoxy equivalent: according to Japanese Industrial Standard (JIS) K7236.

(2) Softening point: measured according to JIS K7234 by the ring and ball method. Specifically, an automatic softening point device (ASP-MG 4, manufactured by Mindacco Ltd.) was used.

(3) Glass transition temperature: the DSC · Tgm (the intermediate temperature of the variation curve with respect to the tangent line between the glass state and the rubber state) when measured under a temperature rise condition of 20 ℃/min by a differential scanning calorimetry apparatus (EXSTAR 6000 DSC6200, manufactured by Hitachi high-tech Co., Ltd.) in accordance with the IPC-TM-6502.4.25. c standard is shown.

(4) Copper foil peel strength and interlayer adhesion: the interlayer adhesion was measured by peeling between the 7 th layer and the 8 th layer in accordance with JIS C6481.

(5) Relative dielectric constant and dielectric loss tangent: the dielectric constant and the dielectric loss tangent at a frequency of 1GHz were determined by a capacitance method using a material analyzer (manufactured by Agilent Technologies) in accordance with the IPC-TM-6502.5.5.9 standard.

(6) Flame retardancy: according to UL94, the evaluation was performed by the vertical method. Evaluation was marked with V-0, V-1, and V-2.

Synthesis example 1

100 parts of TX-1468 (an epoxy resin represented by the above formula (5), having an epoxy equivalent of 219, manufactured by Nippon iron-gold chemical Co., Ltd.) and 0.11 part of tetramethylammonium iodide were charged into a glass separable flask equipped with a stirrer, a thermometer, a nitrogen gas introducing device, a condenser and a dropping device, and the temperature was raised while introducing nitrogen gas, and the temperature was maintained at 120 ℃ for 30 minutes to remove water in the system. Then, 11.5 parts of diphenylmethane diisocyanate (NCO concentration: 34%) was added dropwise while heating to 60 ℃ for 3 hours while maintaining the reaction temperature of 130 ℃ to 140 ℃. After the completion of the dropwise addition, stirring was continued for 60 minutes while maintaining the same temperature, thereby obtaining an oxazolidone ring-containing epoxy resin (resin 1). The obtained resin 1 had an oxazolidone ring modification ratio (Rox) of 0.2, an epoxy equivalent of 300 and a softening point of 85 ℃.

Synthesis example 2

100 parts of TX-1468 and 0.12 part of tetramethylammonium iodide were charged into the same apparatus as in Synthesis example 1, and the temperature was raised while introducing nitrogen gas, and the temperature was maintained at 120 ℃ for 30 minutes to remove water from the system. Then, 17.8 parts of toluene diisocyanate (a mixture of 2, 4-toluene diisocyanate (80%) and 2, 6-toluene diisocyanate (20%), NCO concentration: 48%) was added dropwise over a period of 5 hours while maintaining the reaction temperature of 140 to 150 ℃. After the completion of the dropwise addition, stirring was continued for 60 minutes while maintaining the same temperature, thereby obtaining an oxazolidone ring-containing epoxy resin (resin 2). The obtained resin 2 had a modification rate (Rox) of 0.45, an epoxy equivalent of 464 and a softening point of 125 ℃.

Synthesis example 3

100 parts of TX-1468 and 0.12 part of tetramethylammonium iodide were charged into the same apparatus as in Synthesis example 1, and the temperature was raised while introducing nitrogen gas, and the temperature was maintained at 120 ℃ for 30 minutes to remove water from the system. Then, 16.0 parts of cyclohexane-1, 3-diylbis (NCO concentration: 43%) were added dropwise over a period of 5 hours while maintaining the reaction temperature of 140 to 150 ℃. After the completion of the dropwise addition, stirring was continued for 60 minutes while maintaining the same temperature, thereby obtaining an oxazolidone ring-containing epoxy resin (resin 3). The obtained resin 3 had a modification rate (Rox) of 0.36, an epoxy equivalent of 400 and a softening point of 115 ℃.

The content (mass%) of the unreacted epoxy resin was 49% for resin 1, 20% for resin 2, and 33% for resin 3.

Synthesis example 4

The same apparatus as in Synthesis example 1 was charged with 91 parts of 4,4' - (4-methylcyclohexylidene) bisphenol, 358 parts of epichlorohydrin and 4 parts of ion-exchanged water, and the temperature was raised to 50 ℃ while stirring. After the uniform dissolution, 5.3 parts of 49% aqueous sodium hydroxide solution was charged and the reaction was carried out for 3 hours. Then, after the temperature was raised to 64 ℃, the pressure was reduced to such a degree that water was refluxed, 48 parts of 49% sodium hydroxide aqueous solution was added dropwise over 3 hours, and reflux evaporation was performed while separating the solution in a separation tankThe distilled water and epichlorohydrin were returned to the reaction vessel, and water was removed from the system to effect a reaction. After the reaction, the temperature was raised to 70 ℃ to dehydrate the reaction mixture, and the temperature was set to 135 ℃ to recover the remaining epichlorohydrin. The pressure was returned to normal pressure, and 204 parts of Methyl isobutyl ketone (MIBK) was added thereto to dissolve the Methyl isobutyl ketone. 127 parts of ion-exchanged water was added thereto, and the mixture was stirred and left to stand to dissolve the by-produced common salt in water, thereby removing the salt. Then, 2.9 parts of 49% aqueous sodium hydroxide solution was charged, and the reaction was stirred at 80 ℃ for 90 minutes to carry out a purification reaction. MIBK was added and washed several times with water to remove ionic impurities. Recovering the solvent to obtain X of said formula (1)¹Is 4-methylcyclohexylene, R¹H, n is 0.05 epoxy resin (c 4). The epoxy equivalent of the obtained epoxy resin (c4) was 206.

Then, 100 parts of the obtained epoxy resin (c4) and 0.12 part of tetramethylammonium iodide were charged into the same apparatus as in Synthesis example 1, and the temperature was raised while introducing nitrogen gas, and the temperature was maintained at 120 ℃ for 30 minutes to remove water in the system. Next, while maintaining the reaction temperature of 130 ℃ to 140 ℃, 12.2 parts of diphenylmethane diisocyanate was added dropwise over 3 hours while heating to 60 ℃. After the completion of the dropwise addition, stirring was continued for 60 minutes while maintaining the same temperature, thereby obtaining an oxazolidone ring-containing epoxy resin (resin 4). The obtained resin 4 had a modification rate (Rox) of 0.2, an epoxy equivalent of 290 and a softening point of 80 ℃.

Synthesis example 5

Into the same apparatus as in synthesis example 1 were charged 86.5 parts of 4,4' -cyclohexylidenebisphenol, 358 parts of epichlorohydrin and 4 parts of ion-exchanged water, and the temperature was raised to 50 ℃ while stirring. After the uniform dissolution, 5.3 parts of 49% aqueous sodium hydroxide solution was charged and the reaction was carried out for 3 hours. Then, after the temperature was raised to 64 ℃, the pressure was reduced to such an extent that water was refluxed, 48 parts of 49% sodium hydroxide aqueous solution was added dropwise over 3 hours, and in this dropwise addition, water distilled out by reflux and epichlorohydrin were separated by a separation tank, and the epichlorohydrin was returned to the reaction vessel, and the water was removed to the outside of the system to carry out the reaction. After the reaction, the temperature was raised to 70 ℃ to carry out dehydration, and the temperature was setThe remaining epichlorohydrin was recovered at 135 ℃. The pressure was returned to normal pressure, and 204 parts of MIBK was added for dissolution. 127 parts of ion-exchanged water was added thereto, and the mixture was stirred and left to stand to dissolve the by-produced common salt in water, thereby removing the salt. Then, 2.9 parts of 49% aqueous sodium hydroxide solution was charged, and the reaction was stirred at 80 ℃ for 90 minutes to carry out a purification reaction. MIBK was added and washed several times with water to remove ionic impurities. The solvent was recovered to obtain an epoxy resin (c 5). The epoxy resin (c5) is X of the formula (1)¹Is 4-cyclohexylene, R¹H, n is 0.06 of an epoxy resin, and has an epoxy equivalent weight of 200.

Then, 100 parts of the obtained epoxy resin (c5) and 0.11 part of tetramethylammonium iodide were charged into the same apparatus as in Synthesis example 1, and the temperature was raised while introducing nitrogen gas, and the temperature was maintained at 120 ℃ for 30 minutes to remove water in the system. Next, while maintaining the reaction temperature of 130 ℃ to 140 ℃, 12.5 parts of diphenylmethane diisocyanate was added dropwise over 3 hours while heating to 60 ℃. After the completion of the dropwise addition, stirring was continued for 60 minutes while maintaining the same temperature, thereby obtaining an oxazolidone ring-containing epoxy resin (resin H1). The modification ratio (Rox) of the obtained resin H1 was 0.2, the epoxy equivalent was 285, and the softening point was 85 ℃.

Synthesis example 6

Into the same apparatus as in Synthesis example 1 were charged 105 parts of phenol novolak (hydroxyl equivalent: 105; softening point: 130 ℃ C.) and 0.1 part of p-toluenesulfonic acid, and the temperature was raised to 150 ℃. While maintaining the same temperature, 94 parts of styrene was added dropwise over 3 hours, and further stirring was continued at the same temperature for 1 hour. Then, 500 parts of MIBK was added to dissolve the contents, and washing was performed 5 times at 80 ℃. Subsequently, after MIBK was distilled off under reduced pressure, A styrene-modified novolak phenol compound (APN-A) was obtained. The APN-A obtained had A phenolic hydroxyl equivalent of 199 and A softening point of 110 ℃. In the formula (3), with respect to one A¹The average number of substitution of the 1-phenylethyl group of (2) was 0.9.

Synthesis example 7

Into the same apparatus as in Synthesis example 1 were charged 105 parts of phenol novolak (phenolic hydroxyl equivalent: 105; softening point: 67 ℃ C.) and 0.13 part of phenol novolakP-toluenesulfonic acid, heated to 150 ℃. While maintaining the same temperature, 156 parts of styrene was added dropwise over 3 hours, and further stirring was continued at the same temperature for 1 hour. Then, a styrene-modified novolak phenol compound (APN-B) was obtained by the same treatment as in Synthesis example 6. The APN-B obtained had a phenolic hydroxyl equivalent of 261 and a softening point of 75 ℃. Relative to a¹The average number of substitution of the 1-phenylethyl group of (2) was 1.5.

Synthesis example 8

Into the same apparatus as in Synthesis example 1, 210 parts of 1-naphthol aralkyl resin (SN-475, phenolic hydroxyl equivalent 210, softening point 77 ℃ C.) and 0.18 part of p-toluenesulfonic acid were charged and the temperature was raised to 150 ℃. While maintaining the same temperature, 135 parts of styrene was added dropwise over 3 hours, and further stirring was continued at the same temperature for 1 hour. Then, a styrene-modified novolak phenol compound (APN-C) was obtained by the same treatment as in Synthesis example 6. The APN-C obtained had a phenolic hydroxyl equivalent of 345 and a softening point of 88 ℃. Relative to a¹The average number of substitution of the 1-phenylethyl group of (2) was 1.3.

Synthesis example 9

500 parts of phenol and 190 parts of boron trifluoride ether complex were charged into the same apparatus as in Synthesis example 1, and the temperature was raised to 120 ℃. 176 parts of dicyclopentadiene was added dropwise over 6 hours while maintaining the same temperature, and the reaction was further carried out at 130 ℃ for 4 hours. Then, neutralization was performed and phenol recovery was performed. Further, 500 parts of MIBK was added to dissolve the contents, and washing with water was performed 4 times at 80 ℃. Subsequently, after MIBK was distilled off under reduced pressure, a dicyclopentadiene/phenol co-condensation resin was obtained.

Then, 196 parts of the obtained dicyclopentadiene/phenol cocondensate resin and 0.11 part of p-toluenesulfonic acid were charged into the same apparatus as in synthesis example 1, and the temperature was raised to 150 ℃. While maintaining the same temperature, 31 parts of styrene was added dropwise over 3 hours, and further stirring was continued at the same temperature for 1 hour. Then, a treatment similar to that in Synthesis example 6 was carried out to obtain a substituent-containing novolak phenol compound (APN-D). The APN-D obtained had a phenolic hydroxyl equivalent of 228 and a softening point of122 deg.C. Relative to a¹The average number of substitution of the 1-phenylethyl group of (2) was 0.3.

Synthesis example 10

500 parts of phenol and 9.5 parts of boron trifluoride ether complex were charged into the same apparatus as in Synthesis example 1, and the temperature was raised to 120 ℃. While maintaining the same temperature, 88 parts of dicyclopentadiene was added dropwise over 6 hours, and the reaction was further carried out at 130 ℃ for 4 hours. Then, neutralization was performed and phenol recovery was performed. Further, 300 parts of MIBK was added to dissolve the contents, and washing with water was performed 4 times at 80 ℃. Subsequently, after MIBK was distilled off under reduced pressure, a dicyclopentadiene/phenol co-condensation resin was obtained.

Then, 178 parts of the obtained dicyclopentadiene/phenol cocondensate resin and 0.11 part of p-toluenesulfonic acid were charged into the same apparatus as in synthesis example 1, and the temperature was raised to 150 ℃. While maintaining the same temperature, 32 parts of benzyl alcohol was added dropwise over 3 hours, and further stirring was continued at the same temperature for 1 hour. Then, a treatment similar to that in Synthesis example 6 was carried out to obtain a substituent-containing novolak phenol compound (APN-E). The APN-E obtained had a phenolic hydroxyl equivalent of 205 and a softening point of 90 ℃. Relative to a¹The average number of substitution of the benzyl group of (2) is 0.3.

The abbreviations used in the examples and comparative examples are as follows.

(epoxy resin)

(1) Epoxy resin (a) containing oxazolidone ring

Resin 1 to resin 4: epoxy resins obtained in Synthesis examples 1 to 4

(2) Other epoxy resins

Resin H1: synthesis of epoxy resin obtained in example 5

TX-1468: the above-mentioned

YDPN-638: phenol novolac type epoxy resin (Epotohto YDPN-638 epoxy equivalent 176 manufactured by Nissian iron-on-gold chemical Co., Ltd.)

KDCP-130: dicyclopentadiene type epoxy resin (KDCP-130, epoxy equivalent 254, made by Kyoto chemical Co., Ltd.)

(hardening agent)

(1) Bisphenol compound (b1)

BisP-TMC: 4,4' - (3,3, 5-trimethylcyclohexylidene) bisphenol (BisP-TMC, phenolic hydroxyl equivalent: 155, manufactured by chemical industries, Ltd., of our state)

BisP-MC: 4,4' - (4-methylcyclohexylidene) bisphenol (reagent, phenolic hydroxyl equivalent)

(2) Novolac phenol compound (b2)

APN-A to APN-E: novolac phenol compounds obtained in Synthesis examples 6 to 10

(3) Other hardening agents

PN: phenol novolac resin (Showa Denko K.K., Shonol BRG-557, phenolic hydroxyl equivalent 105, softening point 80 ℃ C.)

Bis-Z: 4,4' -cyclohexylidenebisphenol (Bis-Z, phenolic hydroxyl equivalent 134, manufactured by chemical industries, Ltd., Japan)

DCPD: dicyclopentadiene-phenol compound (GDP 9140, manufactured by Rong chemical Co., Ltd., phenolic hydroxyl equivalent of 196, softening point of 130 ℃ C.)

(hardening accelerator)

2E4 MZ: 2-Ethyl-4-methylimidazole (manufactured by Siguohuainization industries, Ltd., Corlifu (Curezol)2E4MZ)

(flame retardant)

SPE-100: phosphazene flame retardant (SPE-100, available from Otsuka chemical Co., Ltd., phosphorus content: 13%)

Example 1

An epoxy resin varnish was prepared by mixing 100 parts of resin 1 as an epoxy resin, 29.0 parts of BisP-TMC as A curing agent, 29.0 parts of APN-A and 0.2 parts of 2E4MZ as A curing accelerator, and dissolving the mixture in A solvent mixture prepared from MEK, propylene glycol monomethyl ether and N, N-dimethylformamide.

Impregnating the obtained epoxy resin composition varnish into glass cloth, and drying the glass cloth in a hot air circulation oven at 150 DEG C

The obtained epoxy resin composition varnish was impregnated into a glass cloth (type ISO7628, thickness 0.16 mm). The impregnated glass cloth was dried in a hot air circulating oven at 150 ℃ to obtain a prepreg. 8 pieces of the obtained prepreg were subjected to vacuum pressing at 2MPa under a temperature condition of 130 ℃ for 15 minutes +190 ℃ for 80 minutes, to obtain a laminate sheet having a thickness of 1.6mm, by vertically laminating copper foils (manufactured by Mitsui Metal mining Co., Ltd., 3EC-III, thickness 35 μm). The results of the glass transition temperature, the copper foil peel strength, and the interlayer adhesion of the laminate are shown in table 1.

The obtained prepreg was unwound and sieved to obtain a powdery prepreg powder having a 100-mesh size. The prepreg powder was put into a fluororesin mold, and vacuum-pressed at 2MPa under the temperature conditions of 130 ℃ × 15 minutes +190 ℃ × 80 minutes to obtain a test piece 50mm square × 2mm thick. The results of the relative dielectric constant and the dielectric loss tangent of the test piece are shown in Table 1.

Examples 2 to 8

The compositions were mixed in the amounts (parts) shown in Table 1, and the same operation was carried out using the same apparatus as in example 1 to obtain a laminate and a test piece. The same test as in example 1 was carried out, and the results are shown in table 1. In addition, "b 1/b2 (equivalent ratio)" in the table indicates the equivalent ratio (molar ratio) of the bisphenol compound (b1) to the novolak phenol compound (b 2). In all examples and comparative examples, the equivalent ratio (molar ratio) of the epoxy resin (a) to the curing agent (B) was 1.0.

Comparative examples 1 to 7

The compositions were mixed at the mixing amounts (parts) shown in Table 2, and the same operation was carried out using the same apparatus as in example 1 to obtain a laminate and a test piece. The same test as in example 1 was carried out, and the results are shown in table 2.

[ Table 1]

Examples	1	2	3	4	5	6	7	8
									Resin 1	100	100	100	100	100	100	100	100
BisP-TMC	29.0	6.4	47.5	32.4	35.6	30.7	29.4	-
									BisP-MC	-	-	-	-	-	-	-	27.5
APN-A	29.0	58.0	5.3	-	-	-	-	27.5
									APN-B	-	-	-	32.4	-	-	-	-
APN-C	-	-	-	-	35.6	-	-	-
									APN-D	-	-	-	-	-	30.7	-	-
APN-E	-	-	-	-	-	-	29.4	-
									2E4MZ	0.2	0.2	0.2	0.2	0.2	0.2	0.2	0.2
b1/b2 (equivalence ratio)	56/44	12/88	92/8	63/34	69/31	60/40	57/43	59/41
									Glass transition temperature (. degree. C.)	182	180	183	175	165	186	188	175
Copper foil peel strength (kN/m)	1.6	1.4	1.8	1.6	1.6	1.4	1.4	1.6
									Interlayer adhesion (kN/m)	1.5	1.1	2.1	1.5	1.5	1.4	1.4	1.7
Relative dielectric constant	2.9	2.9	2.8	2.8	2.9	2.9	2.8	2.9
									Dielectric loss tangent	0.012	0.011	0.013	0.010	0.011	0.013	0.012	0.013

[ Table 2]

Comparative example	1	2	3	4	5	6	7
								Resin 1	100	100	100	100	100	100	100
BisP-TMC	51.6	-	-	-	-	20.8	28.8
								BisP-MC	-	47.0	-	-	-	-	-
APN-A	-	-	66.3	-	26.7	-	-
								APN-D	-	-	-	75.9	-	-	-
Bis-Z	-	-	-	-	26.7	-	-
								PN	-	-	-	-	-	20.8	-
DCPD	-	-	-	-	-	-	28.8
								2E4MZ	0.2	0.2	0.2	0.2	0.2	0.2	0.2
Glass transition temperature (. degree. C.)	184	155	178	188	165	185	186
								Copper foil peel strength (kN/m)	1.6	1.8	1.3	1.4	1.6	1.7	1.6
Interlayer adhesion (kN/m)	2.2	2.1	0.7	1.2	1.6	1.7	1.8
								Relative dielectric constant	2.9	2.9	2.9	3.0	2.9	3.0	3.0
Dielectric loss tangent	0.015	0.016	0.011	0.015	0.013	0.016	0.016

Examples 9 to 12 and comparative examples 8 to 10

The compositions were mixed at the mixing amounts (parts) shown in Table 3, and the same operation was carried out using the same apparatus as in example 1 to obtain a laminate and a test piece. The same test as in example 1 was carried out, and the results are shown in table 3.

[ Table 3]

Examples 13 to 16 and comparative example 11

The compositions were mixed at the mixing amounts (parts) shown in Table 4, and the same operations were carried out using the same apparatus as in example 1 to obtain a laminate and a test piece. The flame retardant is prepared in such an amount that the phosphorus content of the epoxy resin composition becomes 2.5%. The same test as in example 1 was carried out, and the results are shown in table 4. The test pieces for flame retardancy measurement were prepared by etching both surfaces of the laminate, and the results of flame retardancy test using the test pieces are shown in table 4.

[ Table 4]

[ Industrial Applicability ]

The epoxy resin composition and the cured product thereof of the present invention are excellent in heat resistance, adhesiveness, and dielectric properties, and can be used as an epoxy resin composition for applications such as cured epoxy resin products, prepregs, and laminates. Further, an epoxy resin composition containing a flame retardant and a cured product thereof are excellent in flame retardancy, heat resistance, adhesiveness and dielectric properties, and can be used as an epoxy resin composition for high-functional material applications such as electronic circuit board materials which meet recent requirements for high functionality.

Claims

1. An epoxy resin composition comprising an epoxy resin (A) and a hardener (B), the epoxy resin composition being characterized in that: the epoxy resin (A) contains an oxazolidone ring-containing epoxy resin (a) obtained from an epoxy resin (c) represented by the following formula (1) and an isocyanate compound (d), the hardener (B) contains a bisphenol compound (B1) represented by the following formula (2) and a novolak phenol compound (B2) represented by the following formula (3),

in the formula, X¹A cycloalkylene group having 5 to 8 ring members and having at least one C1-20 hydrocarbon group as a substituent; r¹Each independently represents a hydrogen atom, a halogen atom, a halogenated hydrocarbon group having 1 to 20 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms and having a hetero atom; g represents a glycidyl group; n represents the number of repetitions, and the average value is 0 to 5;

in the formula, X²A cycloalkylene group having 5 to 8 ring members and having at least one C1-20 hydrocarbon group as a substituent; r²Each independently represents a hydrogen atom, a halogen atom, a C1-20 halogenated hydrocarbon group, or a C1 with hetero atomA hydrocarbyl group of about 20;

in the formula, A¹Each independently represents an aromatic ring group selected from a benzene ring, a naphthalene ring, or a biphenyl ring, and these aromatic ring groups may have a C1-49 hydrocarbon group which may have a hetero atom as a substituent, and have 0.1 to 2.5 substituents on average selected from a C6-48 aryl group, a C6-48 aryloxy group, a C7-49 aralkyl group, and a C7-49 aralkyloxy group;

t represents a divalent aliphatic cyclic hydrocarbon group or a divalent crosslinking group represented by the following formula (3a) or (3 b); k represents 1 or 2; m represents a repetition number, and the average value is 1.5 or more;

in the formula, R³And R⁴Each independently represents a hydrogen atom or a C1-20 hydrocarbon group which may have a hetero atom; r⁵And R⁶Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms; a. the²An aromatic ring group selected from a benzene ring, a naphthalene ring and a biphenyl ring, and the aromatic ring group may have a C1-20 hydrocarbon group which may have a hetero atom as a substituent.

2. The epoxy resin composition according to claim 1, characterized in that: the mass ratio of the bisphenol compound (b1) to the novolac phenol compound (b2) is in the range of 5/95 to 95/5.

3. The epoxy resin composition according to claim 1 or 2, characterized in that: the bisphenol compound (b1) is 4,4'- (3,3, 5-trimethylcyclohexylidene) bisphenol or 4,4' - (3,3,5, 5-tetramethylcyclohexylidene) bisphenol.

4. The epoxy resin composition according to claim 1 or 2, characterized in that: the novolak phenol compound (b2) is a phenol compound represented by the following formula (4),

in the formula, R⁷Each independently represents a C1-6 hydrocarbon group, R⁸Is a substituent represented by the following formula (4 a); p is 0.1 to 2.5 on average, q is a number of 0 to 2, and p + q is 0.1 to 3 on average; m is as defined for formula (3);

5. The epoxy resin composition according to claim 1 or 2, characterized in that: the active hydrogen group of the curing agent (B) is 0.2 to 1.5 moles based on 1 mole of the epoxy group of the epoxy resin (A).

6. An epoxy resin cured product characterized by comprising: the epoxy resin composition according to any one of claims 1 to 5 is hardened.