Polyvalent hydroxy resins, epoxy resins, methods for producing them, epoxy resin compositions and cured products thereof

Abstract

Provided are an epoxy resin composition that exhibits excellent low dielectric characteristics, a polyhydric hydroxy resin and epoxy resin that provide this epoxy resin composition, and methods for producing the preceding. The polyhydric hydroxy resin is characterized by being represented by general formula (1). [Chem. 1]

Description

[Technical Field]

[0001] The present invention relates to a polyvalent hydroxy resin or epoxy resin that exhibits excellent low viscosity and low dielectric properties, and a method for producing the same. [Background technology]

[0002] Epoxy resins are used in a wide range of applications, including paints, civil engineering adhesives, casting, electrical and electronic materials, and film materials, due to their excellent adhesive properties, flexibility, heat resistance, chemical resistance, insulation, and curing reaction. In particular, they are widely used in printed circuit board applications, a type of electrical and electronic material, by imparting flame retardancy to epoxy resins.

[0003] In recent years, information devices have become smaller and more high-performance at an accelerating pace, and consequently, materials used in the fields of semiconductors and electronic components are required to have higher performance than ever before. In particular, epoxy resin compositions used as materials for electrical and electronic components require low dielectric properties to accommodate the thinning and high-performance nature of substrates.

[0004] Until now, dicyclopentadienephenol resins with aliphatic skeletons have been used to lower the dielectric constant for laminate applications, but these have been ineffective in improving the dielectric loss tangent, and have not provided satisfactory low viscosity for increasing the amount of filler (Patent Documents 1 and 2). Furthermore, although dielectric properties have been improved by using aromatically modified dicyclopentadienephenol resins, it has not been possible to achieve both low dielectric properties and low viscosity (Patent Document 3). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2001-240654 [Patent Document 2] Japanese Patent Application Publication No. 5-339341 [Patent Document 3] Japanese Patent Publication No. 2016-69524

Summary of the Invention

[0006] Therefore, the problem to be solved by the present invention is to provide a polyhydroxy resin that exhibits excellent dielectric tangent and can obtain a cured product with good low viscosity, an epoxy resin thereof, an epoxy resin composition using them, and a method for producing them.

[0007] As a result of various studies by the present inventors to solve the above problems, by reacting a dicyclopentadiene-type phenol resin with an aromatic vinyl compound in a specific ratio, an aromatic skeleton derived from the aromatic vinyl compound can be added to the phenol ring of the dicyclopentadiene-type phenol resin. Furthermore, it has been found that the epoxy resin obtained when this phenol resin is epoxidized is excellent in low viscosity, and when cured with a curing agent, the obtained cured product has excellent low dielectric properties, and the present invention has been completed.

[0008] That is, the present invention is a polyhydroxy resin (A) characterized by being represented by the following general formula (1).

Chemical formula

[0009] The above R 1A methyl group or a phenyl group is preferred, and i is preferably 1 or 2.

[0010] The present invention also relates to a method for producing a polyhydroxy resin, which comprises reacting a polyhydroxy resin (a) represented by the following general formula (4) with an aromatic vinyl compound (b) represented by the following general formula (5a) and / or general formula (5b).

Chemical formula

Chemical formula

[0011] The above production method is preferably carried out in the presence of an acid catalyst. Preferably, 0.05 to 2.0 mol of the above aromatic vinyl compound is reacted with 1 mol of the phenolic hydroxyl group of the above polyhydroxy resin at a reaction temperature of 50 to 200 °C.

[0012] The present invention also relates to an epoxy resin characterized by being represented by the following general formula (6).

Chemical formula

[0013] The present invention also provides a method for producing epoxy resin, characterized by reacting 1 to 20 moles of epihalohydrin with 1 mole of phenolic hydroxyl groups of the polyvalent hydroxy resin (A) in the presence of an alkali metal hydroxide.

[0014] Furthermore, the present invention relates to an epoxy resin composition containing an epoxy resin and a curing agent, characterized in that the above-mentioned polyvalent hydroxy resin (A) and / or epoxy resin are essential.

[0015] The present invention also relates to a cured product obtained by curing the above epoxy resin composition, and to a prepreg, laminate, or printed circuit board using the above epoxy resin composition.

[0016] The manufacturing method of the present invention allows for the easy addition of an aromatic skeleton derived from an aromatic vinyl compound to the phenol ring of a dicyclopentadiene-type polyvalent hydroxy resin. Furthermore, the cured product using the polyvalent hydroxy resin and / or epoxy resin obtained by this manufacturing method exhibits excellent dielectric loss tangent and provides an epoxy resin composition with excellent copper foil peel strength and interlayer adhesion strength for printed circuit board applications. [Brief explanation of the drawing]

[0017] [Figure 1] This is the GPC chart of the phenolic resin obtained in Example 1. [Figure 2] This is the GPC chart of the epoxy resin obtained in Example 6. [Modes for carrying out the invention]

[0018] The embodiments of the present invention will be described in detail below. The polyvalent hydroxy resin (also called phenolic resin) of the present invention is a polyvalent hydroxy resin (A) represented by the above general formula (1). This resin can be obtained, for example, by reacting a dicyclopentadiene-type polyvalent hydroxy resin (a) represented by the above general formula (4) with an aromatic vinyl compound (b) represented by general formula (5a) and / or general formula (5b) in the presence of a Lewis acid. Here, the polyvalent hydroxy resin (a) has a structure in which phenols are linked by dicyclopentadiene. The polyvalent hydroxy resin (A) of the present invention is a dicyclopentadiene-type polyvalent hydroxy resin (a) in which an aromatic skeleton represented by the above formula (2) is further added to the phenol ring.

[0019] In general formula (1), R 1 represents a hydrocarbon group having 1 to 8 carbon atoms, and preferably an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 8 carbon atoms, an aralkyl group having 7 to 8 carbon atoms, or an allyl group. The alkyl group having 1 to 8 carbon atoms can be linear, branched, or cyclic, and examples include, but are not limited to, methyl, ethyl, propyl, isopropyl, n-butyl, t-butyl, hexyl, cyclohexyl, and methylcyclohexyl groups. The aryl group having 6 to 8 carbon atoms can be, but is not limited to, phenyl, tolyl, xylyl, and ethylphenyl groups. The aralkyl group having 7 to 8 carbon atoms can be, but is not limited to, benzyl and α-methylbenzyl groups. Among these substituents, from the viewpoint of ease of availability and reactivity when cured, the phenyl and methyl groups are preferred, and the methyl group is particularly preferred. 1 The substitution position may be ortho, meta, or para, but the ortho position is preferred.

[0020] R 2 R represents a hydrogen atom or a group represented by formula (2) or formula (3), and at least one of them is formula (2) or formula (3). 2 R is a substituent. 1 Unlike the above, it does not necessarily indicate only substituents, but also hydrogen atoms. The group represented by formula (2) is a group derived from a monovinyl compound represented by general formula (5a) among aromatic vinyl compounds (b), and the group represented by formula (3) is a group derived from a divinyl compound represented by general formula (5b) among aromatic vinyl compounds (b).

[0021] i is a substituent R 1 The number is between 0 and 2, preferably 1 or 2, more preferably 2.

[0022] n1 is a repeating number, representing a number greater than or equal to 0, and its mean value (number mean) is between 0 and 5, preferably between 1.0 and 4.0, more preferably between 1.1 and 3.0, and even more preferably between 1.2 and 2.5.

[0023] In equation (2), R 3 R represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. Examples of hydrocarbon groups having 1 to 8 carbon atoms include R. 1 Similar examples are given. 3 Also, R 2 Similarly, the substituent R 1 Unlike the above, it does not necessarily indicate only substituents, but also hydrogen atoms. When using a monovinyl compound represented by formula (5a) as a raw material, R 3 From the viewpoint of ease of availability and heat resistance of the cured product, hydrogen atoms, methyl groups, and ethyl groups are preferred, and hydrogen atoms and ethyl groups are particularly preferred. When using a divinyl compound represented by formula (5b) as a raw material, R 3 It may also contain a vinyl group. 3 The substitution site may be ortho, meta, or para, but meta and para are preferred. Preferably, R 3 One of them is an ethyl group, and the rest are hydrogen atoms.

[0024] In equation (3), A is obtained from equation (1) by two R 2 The residues excluding R in this case 2 is a hydrogen atom or a group represented by formula (2). In other words, A does not contain a group represented by formula (3).

[0025] R in equation (3) 3 Also, R in equation (2) 3 It is synonymous with [the above]. R 4 R represents a hydrogen atom or a group represented by formula (2). 4 Also, R 2 Ya R 3 Similarly, the substituent R 1 Unlike the above, it does not necessarily indicate only substituents, but also hydrogen atoms.

[0026] p is the repeating number, representing a number greater than or equal to 0, and its mean value (number mean) is between 0.01 and 3, preferably between 0.1 and 2.0, more preferably between 0.2 and 1.0, and even more preferably between 0.3 and 0.8.

[0027] The weight-average molecular weight (Mw) of the phenolic resin of the present invention is preferably 400 to 2000, and more preferably 500 to 1500. The number-average molecular weight (Mn) is preferably 350 to 1500, and more preferably 400 to 1000. The phenolic hydroxyl group equivalent (g / eq.) is preferably 190 to 500, more preferably 200 to 500, and even more preferably 220 to 400. In terms of content by GPC, the molecular weight distribution of the raw material polyvalent hydroxy resin (a) is maintained almost as is, and in general formula (1), preferably, the n1=0 isomer is in the range of 10 area% or less, the n1=1 isomer is in the range of 50 to 90 area%, and the n1=2 or more isomers are in the range of 0 to 50 area%. The softening point is preferably 50 to 180°C, and more preferably 50 to 120°C. The phenolic resin of the present invention exhibits low viscosity, with a melt viscosity of 0.01 to 1.0 Pa·s at 150°C. Preferably, it is 0.03 to 0.5 Pa·s, and more preferably 0.05 to 0.4 Pa·s.

[0028] In general formula (4), R 1 And i are equivalent to the definitions in general formula (1), and m is equivalent to n1 in general formula (1).

[0029] In general formula (5a), R 3 R represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. Examples of hydrocarbon groups having 1 to 8 carbon atoms include R. 1 Similar examples are given. 3 From the viewpoint of ease of availability and heat resistance of the cured product, hydrogen atoms, methyl groups, and ethyl groups are preferred, and hydrogen atoms and ethyl groups are particularly preferred. 3 The substitution site may be ortho, meta, or para, but meta and para are preferred.

[0030] In general formula (5b), the substitution position of the vinyl group may be ortho, meta, or para, but meta and para are preferred, and a mixture thereof may also be used.

[0031] The aromatic vinyl compound (b) represented by general formula (5) requires a monovinyl compound (the compound represented by general formula (5a)) and may also contain a divinyl compound (the compound represented by general formula (5b)). The higher the amount of divinyl compound, the higher the molecular weight of the polyvalent hydroxy resin (A). Therefore, the amount of polyvalent hydroxy resin (a) should be adjusted while taking its molecular weight into consideration to achieve the desired molecular weight. The monovinyl compound undergoes an addition reaction to form a substituent R represented by formula (2). 2 or R 4 This results in a reduction in dielectric properties.

[0032] Examples of monovinyl compounds include vinyl aromatic compounds such as styrene, vinylnaphthalene, vinylbiphenyl, and α-methylstyrene; nuclear alkyl-substituted vinyl aromatic compounds such as o-methylstyrene, m-methylstyrene, p-methylstyrene, o,p-dimethylstyrene, o-ethylvinylbenzene, m-ethylvinylbenzene, p-ethylvinylbenzene, ethylvinylbiphenyl, and ethylvinylnaphthalene; and cyclic vinyl aromatic compounds such as indene, acenaphthylene, benzothiophene, and coumarone. Styrene and ethylvinylbenzene are preferred. These can be used individually or in combination of two or more types.

[0033] Examples of divinyl compounds include divinyl aromatic compounds such as divinylbenzene, divinylnaphthalene, and divinylbiphenyl. Divinylbenzene is preferred. These can be used individually or in combination of two or more types.

[0034] The proportions of monovinyl compound and divinyl compound should be such that the monovinyl compound is 15-50% by mass and the divinyl compound is 50-85% by mass relative to the total amount of vinyl compound. Preferably, the monovinyl compound is 30-50% by mass, more preferably 40-50% by mass. Preferably, the divinyl compound is 50-70% by mass, more preferably 50-60% by mass.

[0035] The above polyvalent hydroxy resin (a) is obtained by reacting dicyclopentadiene with phenols represented by the following general formula (7) in the presence of a Lewis acid. [ka] Here, R 1 And i are equivalent to the definitions in general formula (1).

[0036] The phenolic hydroxyl group equivalent (g / eq.) of this polyvalent hydroxy resin (a) is preferably 160 to 220, more preferably 165 to 210, and even more preferably 170 to 200. In terms of GPC content, it is preferable that the m=0 compound is within 10 area percent or less, the m=1 compound is within 50 to 90 area percent, and the m=2 or more compound is within 0 to 50 area percent.

[0037] Examples of phenols represented by general formula (7) include phenol, cresol, ethylphenol, propylphenol, isopropylphenol, n-butylphenol, t-butylphenol, hexylphenol, cyclohexylphenol, phenylphenol, tolylphenol, benzylphenol, α-methylbenzylphenol, allylphenol, dimethylphenol, diethylphenol, dipropylphenol, diisopropylphenol, di(n-butyl)phenol, di(t-butyl)phenol, dihexylphenol, dicyclohexylphenol, diphenylphenol, ditolylphenol, dibenzylphenol, bis(α-methylbenzyl)phenol, methylethylphenol, methylpropylphenol, methylisopropylphenol, methylbutylphenol, methyl-t-butylphenol, methylallylphenol, tolylphenylphenol, and the like. From the viewpoint of ease of availability and reactivity when cured, phenol, cresol, phenylphenol, dimethylphenol, and diphenylphenol are preferred, with cresol and dimethylphenol being particularly preferred.

[0038] The catalyst used in this reaction is a Lewis acid, specifically boron trifluoride, boron trifluoride-phenol complex, boron trifluoride-ether complex, aluminum chloride, tin chloride, zinc chloride, iron chloride, etc., but boron trifluoride-ether complex is preferred due to its ease of handling. In the case of boron trifluoride-ether complex, the amount of catalyst used is 0.001 to 20 parts by mass, preferably 0.5 to 10 parts by mass, per 100 parts by mass of dicyclopentadiene.

[0039] The ratio of phenols to dicyclopentadiene in the reaction is 0.08 to 0.80 moles, preferably 0.09 to 0.60 moles, more preferably 0.10 to 0.50 moles, even more preferably 0.10 to 0.40 moles, and particularly preferably 0.10 to 0.20 moles of dicyclopentadiene per mole of phenols.

[0040] This reaction is best carried out by charging phenols and a catalyst into a reactor and gradually adding dicyclopentadiene dropwise over 0.1 to 10 hours, preferably 0.5 to 8 hours, and more preferably 1 to 6 hours.

[0041] The reaction temperature is preferably 50 to 200°C, more preferably 100 to 180°C, and even more preferably 120 to 160°C. The reaction time is preferably 1 to 10 hours, more preferably 3 to 10 hours, and even more preferably 4 to 8 hours.

[0042] After the reaction is complete, alkalis such as sodium hydroxide, potassium hydroxide, and calcium hydroxide are added to deactivate the catalyst. Then, solvents such as aromatic hydrocarbons such as toluene and xylene, or ketones such as methyl ethyl ketone and methyl isobutyl ketone are added to dissolve the catalyst, and after washing with water, the solvent is recovered under reduced pressure to obtain the desired dicyclopentadienephenol resin represented by general formula (3). It is preferable to react as much of the dicyclopentadiene as possible and recover any unreacted phenolic raw materials under reduced pressure.

[0043] During the reaction, solvents such as aromatic hydrocarbons like benzene, toluene, and xylene, ketones like methyl ethyl ketone and methyl isobutyl ketone, halogenated hydrocarbons like chlorobenzene and dichlorobenzene, and ethers like ethylene glycol dimethyl ether and diethylene glycol dimethyl ether may be used as needed.

[0044] A reaction method for introducing an aromatic skeleton structure of formula (2) or formula (3) into a polyvalent hydroxy resin (a) is to react the polyvalent hydroxy resin (a) with an aromatic vinyl compound (b) in a predetermined ratio. The reaction ratio is 0.05 to 2.0 moles of aromatic vinyl compound (b) per mole of phenolic hydroxyl groups of polyvalent hydroxy resin (a), more preferably 0.1 to 1.0 moles, even more preferably 0.15 to 0.80 moles, and particularly preferably 0.30 to 0.70 moles.

[0045] The catalyst used in the reaction is an acid catalyst, specifically including mineral acids such as hydrochloric acid, sulfuric acid, and phosphoric acid; organic acids such as formic acid, oxalic acid, trifluoroacetic acid, and p-toluenesulfonic acid; Lewis acids such as zinc chloride, aluminum chloride, iron chloride, and boron trifluoride; or solid acids such as activated clay, silica-alumina, and zeolite. Among these, p-toluenesulfonic acid is preferred due to its ease of handling. In the case of p-toluenesulfonic acid, the amount of catalyst used is 0.001 to 20 parts by mass, preferably 0.5 to 10 parts by mass, per 100 parts by mass of polyvalent hydroxy resin (a).

[0046] This reaction is preferably carried out by charging a polyvalent hydroxy resin (a), a catalyst, and a solvent into a reactor, dissolving them, and then adding the aromatic vinyl compound (b) dropwise over 0.1 to 10 hours, preferably 0.5 to 8 hours, and more preferably 0.5 to 5 hours.

[0047] The reaction temperature is preferably 50 to 200°C, more preferably 100 to 180°C, and even more preferably 120 to 160°C. The reaction time is preferably 1 to 10 hours, more preferably 3 to 10 hours, and even more preferably 4 to 8 hours.

[0048] After the reaction is complete, alkalis such as sodium hydroxide, potassium hydroxide, and calcium hydroxide are added to deactivate the catalyst. Then, solvents such as aromatic hydrocarbons like toluene and xylene, or ketones like methyl ethyl ketone and methyl isobutyl ketone are added to dissolve the catalyst. After washing with water, the solvent is recovered under reduced pressure to obtain the desired phenolic resin.

[0049] The solvents used in the reaction include aromatic hydrocarbons such as benzene, toluene, and xylene; ketones such as methyl ethyl ketone and methyl isobutyl ketone; halogenated hydrocarbons such as chlorobenzene and dichlorobenzene; and ethers such as ethylene glycol dimethyl ether and diethylene glycol dimethyl ether. These solvents may be used individually or in mixtures of two or more.

[0050] The epoxy resin of the present invention is represented by general formula (6). This epoxy resin is obtained by reacting the polyvalent hydroxy resin (A) of the present invention with an epihalohydrin such as epichlorohydrin. This reaction is carried out according to conventionally known methods.

[0051] In general formula (6), R 1 , R 2 , and i are equivalent to the definitions in general formula (1), and n3 is equivalent to n1 in general formula (1).

[0052] For example, epoxidation can be performed by adding an alkali metal hydroxide such as sodium hydroxide in solid or concentrated aqueous form to a mixture of phenol resin and an excess molar amount of epihalohydrin relative to the hydroxyl groups of the phenol resin, and reacting the mixture at a reaction temperature of 30 to 120°C for 0.5 to 10 hours, or by adding a quaternary ammonium salt such as tetraethylammonium chloride as a catalyst to a phenol resin and an excess molar amount of epihalohydrin, reacting the mixture at a temperature of 50 to 150°C for 1 to 5 hours, and then adding an alkali metal hydroxide such as sodium hydroxide in solid or concentrated aqueous form to the resulting polyhalohydrin ether and reacting the mixture at a temperature of 30 to 120°C for 1 to 10 hours.

[0053] In the above reaction, the amount of epihalohydrin used is 1 to 20 times the molar amount relative to the hydroxyl groups of the phenol resin, preferably 2 to 8 times the molar amount. The amount of alkali metal hydroxide used is 0.85 to 1.15 times the molar amount relative to the hydroxyl groups of the phenol resin.

[0054] Since the epoxy resin obtained from these reactions contains unreacted epihalohydrins and alkali metal halides, the unreacted epihalohydrins can be removed from the reaction mixture by evaporation, and the alkali metal halides can be removed by methods such as extraction with water or filtration to obtain the desired epoxy resin.

[0055] The epoxy equivalent (g / eq.) of the epoxy resin of the present invention is preferably 200 to 4000, more preferably 220 to 2000, and even more preferably 250 to 700. In particular, when dicyandiamide is used as a curing agent, the epoxy equivalent is preferably 300 or more in order to prevent the precipitation of dicyandiamide crystals on the prepreg. In terms of content by GPC, the molecular weight distribution of the raw materials, polyvalent hydroxy resin (a) and phenolic resin, is maintained almost as is, and in general formula (6), preferably, the n3=0 isomer is in the range of 10 area% or less, the n3=1 isomer is in the range of 40 to 90 area%, and the n3=2 or more isomers are in the range of 0 to 60 area%. The total chlorine content is preferably 2000 ppm or less, and more preferably 1500 ppm or less. The epoxy resin of the present invention exhibits low viscosity, with a melt viscosity of 0.01 to 1.0 Pa·s at 150°C. Preferably, it is 0.05 to 0.7 Pa·s, and more preferably 0.1 to 0.5 Pa·s.

[0056] An epoxy resin composition of the present invention can be obtained by using the polyvalent hydroxy resin and / or the epoxy resin of the present invention. The epoxy resin composition of the present invention comprises an epoxy resin and a curing agent as essential components. In this embodiment, part or all of the curing agent is the polyvalent hydroxy resin of the present invention, part or all of the epoxy resin is the epoxy resin of the present invention, or part or all of the curing agent is the polyvalent hydroxy resin of the present invention and part or all of the epoxy resin is the epoxy resin of the present invention.

[0057] Preferably, at least 30% by mass of the curing agent is the polyvalent hydroxy resin of the present invention, or at least 30% by mass of the epoxy resin is the epoxy resin of the present invention. More preferably, each is contained at 50% by mass or more, and even more preferably at 70% by mass. If the amount is less than this, the dielectric properties may deteriorate. In other words, if 30% by mass or more of the curing agent is the polyvalent hydroxy resin of the present invention, the epoxy resin does not need to be the epoxy resin of the present invention, and if the polyvalent hydroxy resin of the present invention is less than 30% by mass of the curing agent, it is essential that 30% by mass or more of the epoxy resin is the epoxy resin of the present invention.

[0058] As the epoxy resin used to obtain the epoxy resin composition of the present invention, one or more types of epoxy resins may be used in combination as needed.

[0059] Any conventional epoxy resin having two or more epoxy groups in its molecule can be used in combination with this product. For example, trifunctional epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, tetramethylbisphenol F type epoxy resin, hydroquinone type epoxy resin, biphenyl type epoxy resin, stilbene type epoxy resin, bisphenol fluorene type epoxy resin, bisphenol S type epoxy resin, bisthioether type epoxy resin, resorcinol type epoxy resin, biphenyl aralkylphenol type epoxy resin, naphthalenediol type epoxy resin, phenol novolac type epoxy resin, aromatic modified phenol novolac type epoxy resin, cresol novolac type epoxy resin, alkyl novolac type epoxy resin, bisphenol novolac type epoxy resin, binaphthol type epoxy resin, naphthol novolac type epoxy resin, β-naphthol aralkyl type epoxy resin, dinaphthol aralkyl type epoxy resin, α-naphthol aralkyl type epoxy resin, trisphenylmethane type epoxy resin, and tetrafunctional epoxy resins such as tetrakisphenylethane type epoxy resin. Other examples of epoxy resins include, but are not limited to, dicyclopentadiene-type epoxy resins, polyhydric alcohol polyglycidyl ethers such as 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, trimethylolethane polyglycidyl ether, and pentaerythritol polyglycidyl ether; alkylene glycol-type epoxy resins such as propylene glycol diglycidyl ether; aliphatic cyclic epoxy resins such as cyclohexanedimethanol diglycidyl ether; glycidyl esters such as dimer acid polyglycidyl esters; glycidylamine-type epoxy resins such as phenyl diglycidylamine, tol diglycidylamine, diaminodiphenylmethane tetraglycidylamine, and aminophenol-type epoxy resins; alicyclic epoxy resins such as Celoxide 2021P (manufactured by Daicel Corporation); phosphorus-containing epoxy resins; bromine-containing epoxy resins; urethane-modified epoxy resins; and oxazolidone ring-containing epoxy resins.Furthermore, these epoxy resins may be used individually or in combination of two or more types. From the viewpoint of availability, it is even more preferable to use epoxy resins represented by the following general formula (8), or dicyclopentadiene type epoxy resins other than those of the present invention, naphthalenediol type epoxy resins, phenol novolac type epoxy resins, aromatic modified phenol novolac type epoxy resins, cresol novolac type epoxy resins, α-naphthol aralkyl type epoxy resins, dicyclopentadiene type epoxy resins, phosphorus-containing epoxy resins, or oxazolidone ring-containing epoxy resins.

[0060] [ka] Here, R 5 These independently represent hydrocarbon groups having 1 to 8 carbon atoms, such as alkyl groups including methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, n-hexyl, and cyclohexyl groups, and may be the same or different from each other. X represents a divalent organic group, such as an alkylene group including a methylene group, ethylene group, isopropyledene group, isobutylene group, hexafluoroisopropylidene group, -CO-, -O-, -S-, -SO2-, -SS-, or an aralkylene group represented by formula (8a). R 6 Each of these independently represents a hydrogen atom or a hydrocarbon group having one or more carbon atoms, for example, a methyl group, and they may be the same or different from each other. Ar is a benzene ring or a naphthalene ring, and these benzene rings or naphthalene rings may have substituents such as an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an aryl group having 6 to 11 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, an aryloxy group having 6 to 11 carbon atoms, or an aralkyloxy group having 7 to 12 carbon atoms.

[0061] As a curing agent, in addition to the polyvalent hydroxy resin (A) of general formula (1), one or more commonly used curing agents such as various phenolic resins, acid anhydrides, amines, cyanate esters, activated esters, hydrazides, acidic polyesters, and aromatic cyanates may be used in combination as needed. When these curing agents are used in combination, the amount of the combined curing agent is preferably 70% by mass or less, and more preferably 50% by mass or less, of the total curing agent. If the proportion of the combined curing agent is too high, the dielectric properties of the epoxy resin composition may deteriorate.

[0062] In the epoxy resin composition of the present invention, the molar ratio of active hydrogen groups of the curing agent to 1 mole of epoxy groups of the total epoxy resin is preferably 0.2 to 1.5 moles, more preferably 0.3 to 1.4 moles, even more preferably 0.5 to 1.3 moles, and particularly preferably 0.8 to 1.2 moles. If the ratio deviates from this range, curing may be incomplete, and good cured properties may not be obtained. For example, when using a phenol resin-based curing agent or an amine-based curing agent, the active hydrogen groups are blended in approximately equimolar amounts to the epoxy groups. When using an acid anhydride-based curing agent, the acid anhydride groups are blended in an amount of 0.5 to 1.2 moles, preferably 0.6 to 1.0 moles, per mole of epoxy groups. When using the phenol resin of the present invention alone as a curing agent, it is desirable to use it in a range of 0.9 to 1.1 moles per mole of epoxy resin.

[0063] In this invention, an active hydrogen group refers to a functional group having active hydrogen that reacts with epoxy groups (including functional groups having latent active hydrogen that generates active hydrogen through hydrolysis, etc., and functional groups that exhibit equivalent curing activity). Specifically, examples include acid anhydride groups, carboxyl groups, amino groups, and phenolic hydroxyl groups. Regarding active hydrogen groups, 1 mole of carboxyl groups or phenolic hydroxyl groups is calculated as 1 mole, and 2 moles of amino groups (NH2). If 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 such as phenyl glycidyl ether with a known epoxy equivalent with a curing agent whose active hydrogen equivalent is unknown, and measuring the amount of monoepoxy resin consumed.

[0064] Specific examples of phenolic resin curing agents that can be used in the epoxy resin composition of the present invention include bisphenol A, bisphenol F, bisphenol C, bisphenol K, bisphenol Z, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F, tetramethylbisphenol S, tetramethylbisphenol Z, tetrabromobisphenol A, dihydroxydiphenyl sulfide, 4,Bisphenols such as 4'-thiobis(3-methyl-6-t-butylphenol), dihydroxybenzenes such as catechol, resorcinol, methylresorcinol, hydroquinone, monomethylhydroquinone, dimethylhydroquinone, trimethylhydroquinone, mono-t-butylhydroquinone, and di-t-butylhydroquinone, hydroxynaphthalenes such as dihydroxynaphthalene, dihydroxymethylnaphthalene, dihydroxymethylnaphthalene, and trihydroxynaphthalene, phosphorus-containing phenol curing agents such as LC-950PM60 (manufactured by Shin-AT&C), phenol novolac resins such as Shonol BRG-555 (manufactured by Aica Kogyo Co., Ltd.), cresol novolac resins such as DC-5 (manufactured by Nippon Steel Chemical & Material Co., Ltd.), triazine skeleton-containing phenol resins, aromatically modified phenol novolac resins, bisphenol A novolac resins, and trishydroxyphenylmethane-type novolac resins such as Resitopp TPM-100 (manufactured by Gun-ei Chemical Industry Co., Ltd.) Examples include phenol compounds known as novolac phenol resins, such as naphthol novolac resins, phenols such as naphthol novolac resins, condensates of naphthols and / or bisphenols with aldehydes, phenols such as SN-160, SN-395, SN-485 (manufactured by Nippon Steel Chemical & Material Co., Ltd.), condensates of phenols and / or naphthols and / or bisphenols with xylylene glycol, condensates of phenols and / or naphthols with isopropenylacetophenone, reaction products of phenols and / or naphthols and / or bisphenols with dicyclopentadiene, reaction products of phenols and / or naphthols and / or bisphenols with divinylbenzene, reaction products of phenols and / or naphthols and / or bisphenols with terpenes, and condensates of phenols and / or naphthols and / or bisphenols with biphenyl crosslinking agents, polybutadiene-modified phenol resins, and phenol resins having spiro rings. From the viewpoint of availability, phenol novolac resins, dicyclopentadienephenol resins, trishydroxyphenylmethane-type novolac resins, aromatically modified phenol novolac resins, etc., are preferred.

[0065] Novolac phenol resin can be obtained from phenols and crosslinking agents. Examples of phenols include phenol, cresol, xylenol, butylphenol, amylphenol, nonylphenol, butylmethylphenol, trimethylphenol, and phenylphenol. Examples of naphthols include 1-naphthol and 2-naphthol. In addition, bisphenols, which were listed as phenol resin curing agents above, can be used. Examples of aldehydes used as crosslinking agents include formaldehyde, acetaldehyde, propylaldehyde, butyraldehyde, valeraldehyde, caproaldehyde, benzaldehyde, chloraldehyde, bromaldehyde, glyoxal, malonaldehyde, succinaldehyde, glutaraldehyde, adipinealdehyde, pimelinaldehyde, sebacinaldehyde, acrolein, crotonaldehyde, salicylaldehyde, phthalaldehyde, and hydroxybenzaldehyde. Examples of biphenyl-based crosslinking agents include bis(methylol)biphenyl, bis(methoxymethyl)biphenyl, bis(ethoxymethyl)biphenyl, and bis(chloromethyl)biphenyl.

[0066] Examples of acid anhydride-based curing agents include maleic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, methylbicyclo[2.2.1]heptane-2,3-dicarboxylic acid anhydride, bicyclo[2.2.1]heptane-2,3-dicarboxylic acid anhydride, 1,2,3,6-tetrahydrophthalic anhydride, pyromellitic anhydride, phthalic anhydride, trimellitic anhydride, methylnadic acid, copolymers of styrene monomer and maleic anhydride, copolymers of indenes and maleic anhydride, and the like.

[0067] Examples of amine-based curing agents include, specifically, diethylenetriamine, triethylenetetramine, metaxylenediamine, isophoronediamine, diaminodiphenylmethane, diaminodiphenylsulfone, diaminodiphenyl ether, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, polyetheramines, biguanide compounds, dicyandiamide, anisidine and other aromatic amines, and amine compounds such as polyamidoamines, which are condensates of acids such as dimer acids and polyamines.

[0068] The cyanate ester compound is not particularly limited as long as it is a compound having two or more cyanate groups (cyanate ester groups) in one molecule. Examples include novolac-type cyanate ester curing agents such as phenol novolac type and alkylphenol novolac type, naphthol aralkyl-type cyanate ester curing agents, biphenylalkyl-type cyanate ester curing agents, dicyclopentadiene-type cyanate ester curing agents, bisphenol-type cyanate ester curing agents such as bisphenol A type, bisphenol F type, bisphenol E type, tetramethylbisphenol F type, and bisphenol S type, and prepolymers in which these are partially triazined. Specific examples of cyanate ester-based curing agents include, for example, bisphenol A dicyanate, polyphenol cyanate (oligo(3-methylene-1,5-phenylene cyanate), bis(3-methyl-4-cyanatophenyl)methane, bis(3-ethyl-4-cyanatophenyl)methane, bis(4-cyanatophenyl)-1,1-ethane, 4,4-dicyanate-diphenyl, 2,2-bis(4-cyanatophenyl)-1,1,1,3,3,3-hexafluoropropane, 4,4'-methylenebis(2,6-dimethylphenyl cyanate), 4,4'-ethylidenediphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanato)phenylpropane, 1,1-bis(4-cyanatophenyl Examples include difunctional cyanate resins such as methane, bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanatephenyl-1-(methylethylidene))benzene, bis(4-cyanatephenyl)thioether, and bis(4-cyanatephenyl)ether; cyanate esters of trivalent phenols such as tris(4-cyanatephenyl)-1,1,1-ethane and bis(3,5-dimethyl-4-cyanatephenyl)-4-cyanatephenyl-1,1,1-ethane; polyfunctional cyanate resins derived from phenol novolacs, cresol novolacs, and phenol resins containing dicyclopentadiene structures; and prepolymers in which these cyanate resins are partially triazined. One or more of these can be used.

[0069] While there are no particular restrictions on the active ester curing agent, compounds having two or more highly reactive ester groups in one molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds, are generally preferred. The active ester curing agent is preferably obtained by a condensation reaction between a carboxylic acid compound and / or a thiocarboxylic acid compound and a hydroxy compound and / or a thiol compound. Particularly from the viewpoint of improving heat resistance, an active ester curing agent obtained from a carboxylic acid compound and a hydroxy compound is preferred, and an active ester curing agent obtained from a carboxylic acid compound and / or a naphthol compound is more preferred. Examples of carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid. Examples of phenol compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalein, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadienyldiphenol, dicyclopentadienphenol resin (a precursor of the epoxy resin of the present invention), phenol novolac, and the like. One or more active ester curing agents can be used. As active ester curing agents, specifically, active ester curing agents containing a dicyclopentadienyldiphenol structure, active ester curing agents containing a naphthalene structure, active ester curing agents that are acetylated phenol novolacs, and active ester curing agents that are benzoylated phenol novolacs are preferred, and among these, active ester curing agents containing a dicyclopentadienyldiphenol structure, which is a precursor of the epoxy resin of the present invention, are more preferred in that they are excellent in improving peel strength.

[0070] Other curing agents include, specifically, phosphine compounds such as triphenylphosphine, phosphonium salts such as tetraphenylphosphonium bromide, imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, and 1-cyanoethyl-2-methylimidazole, imidazole salts which are salts of imidazoles with trimellitic acid, isocyanuric acid, or boron, etc., quaternary ammonium salts such as trimethylammonium chloride, diazabicyclo compounds, salts of diazabicyclo compounds with phenols or phenol novolac resins, etc., complex compounds of boron trifluoride with amines or ether compounds, aromatic phosphoniums, or iodonium salts.

[0071] A curing accelerator may be used in the epoxy resin composition as needed. Examples of usable curing accelerators include imidazoles such as 2-methylimidazole, 2-ethylimidazole, and 2-ethyl-4-methylimidazole; tertiary amines such as 4-dimethylaminopyridine, 2-(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)undecene-7; phosphines such as triphenylphosphine, tricyclohexylphosphine, and triphenylphosphinetriphenylborane; and metal compounds such as tin octylate. When using a curing accelerator, the amount used is preferably 0.02 to 5 parts by mass per 100 parts by mass of the epoxy resin component in the epoxy resin composition of the present invention. By using a curing accelerator, the curing temperature can be lowered and the curing time can be shortened.

[0072] The epoxy resin composition may be used with an organic solvent or reactive diluent to adjust its viscosity.

[0073] Examples of organic solvents 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 diglycol, and pine oil; and vinegar. Examples of acetate esters such as butyl acid, methoxybutyl acetate, methyl cellosolve acetate, cellosolve acetate, ethyl diglycol acetate, propylene glycol monomethyl ether acetate, carbitol acetate, and benzyl alcohol acetate; benzoic acid esters such as methyl benzoate and ethyl benzoate; cellosolves such as methyl cellosolve, cellosolve, and butyl cellosolve; carbitols such as methyl carbitol, carbitol, and butyl carbitol; aromatic hydrocarbons such as benzene, toluene, and xylene; and dimethyl sulfoxide, acetonitrile, and N-methylpyrrolidone, but are not limited to these.

[0074] Examples of reactive diluents include, but are not limited to, monofunctional glycidyl ethers such as allyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, and tolyl glycidyl ether, as well as monofunctional glycidyl esters such as neodecanoic acid glycidyl ester.

[0075] These organic solvents or reactive diluents are preferably used in the resin composition, either individually or in mixtures of several types, at a non-volatile content of 90% by mass or less, and the appropriate type and amount are selected as appropriate depending on the application. For example, in printed circuit board applications, polar solvents with a boiling point of 160°C or less, such as methyl ethyl ketone, acetone, and 1-methoxy-2-propanol, are preferred, and the amount used in the resin composition is preferably 40 to 80% by mass in terms of non-volatile content. In adhesive film applications, for example, ketones, acetate esters, carbitols, aromatic hydrocarbons, dimethylformamide, dimethylacetamide, and N-methylpyrrolidone are preferred, and the amount used is preferably 30 to 60% by mass in terms of non-volatile content.

[0076] The epoxy resin composition may contain other thermosetting resins or thermoplastic resins to the extent that it does not impair the properties. Examples include, but are not limited to, phenolic resins, benzoxazine resins, bismaleimide resins, bismaleimidotriazine resins, acrylic resins, petroleum resins, indene resins, coumarone indene resins, phenoxy resins, polyurethane resins, polyester resins, polyamide resins, polyimide resins, polyamideimide resins, polyetherimide resins, polyphenylene ether resins, modified polyphenylene ether resins, polyethersulfone resins, polysulfone resins, polyetheretherketone resins, polyphenylene sulfide resins, polyvinyl formal resins, polysiloxane compounds, and alkylene resins containing reactive functional groups such as hydroxyl group-containing polybutadiene.

[0077] Various known flame retardants can be used in the epoxy resin composition to improve the flame retardancy of the resulting cured product. Examples of usable flame retardants include halogen-based flame retardants, phosphorus-based flame retardants, nitrogen-based flame retardants, silicone-based flame retardants, inorganic flame retardants, and organometallic salt-based flame retardants. From an environmental standpoint, halogen-free flame retardants are preferred, and phosphorus-based flame retardants are particularly preferred. These flame retardants may be used individually or in combination of two or more types.

[0078] Phosphorus-based flame retardants can be either inorganic phosphorus compounds or organophosphorus compounds. Examples of inorganic phosphorus compounds include ammonium phosphates such as red phosphorus, monoammonium phosphate, diammonium phosphate, triammonium phosphate, and polyammonium phosphate, as well as inorganic nitrogen-containing phosphorus compounds such as phosphate amides. Examples of organophosphorus compounds include aliphatic phosphate esters, phosphate ester compounds, condensed phosphate esters such as PX-200 (manufactured by Daihachi Chemical Industry Co., Ltd.), phosphazenes, phosphonic acid compounds, phosphinic acid compounds, phosphine oxide compounds, phospholane compounds, and organic nitrogen-containing phosphorus compounds, as well as metal salts of phosphinic acid, cyclic organophosphorus compounds such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(2,5-dihydrooxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, and 10-(2,7-dihydrooxynaphthyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, and derivatives obtained by reacting these with compounds such as epoxy resins and phenolic resins, such as phosphorus-containing epoxy resins and phosphorus-containing curing agents.

[0079] The amount of flame retardant added is appropriately selected depending on the type of phosphorus-based flame retardant, the components of the epoxy resin composition, and the desired degree of flame retardancy. For example, the phosphorus content in the organic components (excluding organic solvents) of the epoxy resin composition is preferably 0.2 to 4% by mass, more preferably 0.4 to 3.5% by mass, and even more preferably 0.6 to 3% by mass. If the phosphorus content is too low, it may be difficult to ensure flame retardancy, and if it is too high, it may adversely affect the heat resistance. When using a phosphorus-based flame retardant, a flame retardant aid such as magnesium hydroxide may also be used in combination.

[0080] Fillers may be used in epoxy resin compositions as needed. Specifically, examples include fused silica, crystalline silica, alumina, silicon nitride, aluminum hydroxide, boehmite, magnesium hydroxide, talc, mica, calcium carbonate, calcium silicate, calcium hydroxide, magnesium carbonate, barium carbonate, barium sulfate, boron nitride, carbon, carbon fiber, glass fiber, alumina fiber, silica-alumina fiber, silicon carbide fiber, polyester fiber, cellulose fiber, aramid fiber, ceramic fiber, fine particle rubber, silicone rubber, thermoplastic elastomer, carbon black, and pigments. Generally, the reason for using fillers is to improve impact resistance. In addition, when metal hydroxides such as aluminum hydroxide, boehmite, and magnesium hydroxide are used, they act as flame retardant aids, improving flame retardancy. The amount of these fillers added to the epoxy resin composition is preferably 1 to 150% by mass, and more preferably 10 to 70% by mass. If the amount added is too high, the adhesion required for laminate applications may decrease, and the cured product may become brittle, resulting in insufficient mechanical properties. Furthermore, if the amount of filler used is too small, the intended effects of the filler, such as improved impact resistance of the cured product, may not be realized.

[0081] When epoxy resin compositions are used to form plate-shaped substrates, fibrous materials are preferred as fillers in terms of dimensional stability and flexural strength. More preferably, glass fiber substrates are made by weaving glass fibers into a mesh.

[0082] The epoxy resin composition may further contain various additives as needed, such as silane coupling agents, antioxidants, mold release agents, defoaming agents, emulsifiers, thixotropy-inducing agents, smoothing agents, flame retardants, and pigments. The amount of these additives added is preferably in the range of 0.01 to 20% by mass relative to the epoxy resin composition.

[0083] The epoxy resin composition can be used to create prepregs for use in printed circuit boards and the like by impregnating a fibrous substrate with it. The fibrous substrate can be inorganic fibers such as glass, or woven or nonwoven fabrics of organic fibers such as polyester resin, polyamine resin, polyacrylic resin, polyimide resin, or aromatic polyamide resin, but is not limited to these. The method for producing a prepreg from an epoxy resin composition is not particularly limited, but for example, it can be obtained by immersing the epoxy resin composition in a resin varnish prepared by adjusting the viscosity with an organic solvent, impregnating it, and then heating and drying it to partially cure (B-stage) the resin component. For example, it can be heated and dried at 100 to 200°C for 1 to 40 minutes. Here, the amount of resin in the prepreg is preferably 30 to 80% by mass.

[0084] Furthermore, while the curing method for laminates, commonly used in the manufacture of printed circuit boards, can be used to cure the prepreg, it is not limited to this method. For example, when forming a laminate using a prepreg, one or more prepregs are stacked, metal foil is placed on one or both sides to form a laminate, and this laminate is heated and pressurized to integrate the layers. Here, single, alloy, or composite metal foils of copper, aluminum, brass, nickel, etc., can be used as the metal foil. Then, the prepreg is cured by pressurizing and heating the created laminate to obtain a laminate. At that time, it is preferable to set the heating temperature to 160-220°C, the pressurizing pressure to 5-50 MPa, and the heating and pressurizing time to 40-240 minutes, in order to obtain the desired cured product. If the heating temperature is too low, the curing reaction will not proceed sufficiently, and if it is too high, there is a risk that the epoxy resin composition will begin to decompose. Also, if the pressurizing pressure is too low, air bubbles may remain inside the resulting laminate, which may reduce its electrical properties, and if it is too high, the resin may flow before curing, which may prevent obtaining a cured product of the desired thickness. Furthermore, if the heating and pressurizing time is too short, the curing reaction may not proceed sufficiently, and if it is too long, thermal decomposition of the epoxy resin composition in the prepreg may occur, which is undesirable.

[0085] Epoxy resin compositions can be cured in the same manner as known epoxy resin compositions to obtain a cured epoxy resin product. Methods for obtaining the cured product can be the same as those for known epoxy resin compositions, and methods such as casting, injection, potting, dipping, drip coating, transfer molding, compression molding, etc., or lamination of resin sheets, resin-coated copper foil, prepregs, etc., followed by heating, pressing, and curing to form laminates are preferably used. The curing temperature is typically 100-300°C, and the curing time is typically 1-5 hours.

[0086] The epoxy resin cured product of the present invention can take the form of a laminate, molded product, adhesive product, coating film, film, or the like.

[0087] We prepared epoxy resin compositions and evaluated laminates and cured products by heat curing. As a result, we were able to provide an epoxy-curable resin composition that exhibits excellent low dielectric properties in the cured product. Specifically, the dielectric properties include a relative permittivity of 3.00 or less, more preferably 2.90 or less, and a dielectric loss tangent of 0.015 or less, more preferably 0.010 or less. Furthermore, the glass transition temperature (Tg) of the cured product is 120°C or higher, and it is also possible to raise it to 150°C or higher. [Examples]

[0088] The present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited to these. Unless otherwise specified, "parts" refers to parts by mass, "%" refers to mass percent, and "ppm" refers to mass ppm. The measurements were performed using the following methods.

[0089] • Hydroxyl group equivalent: Measurements were performed in accordance with JIS K 0070 standard, and the unit is expressed as "g / eq.". Unless otherwise specified, the hydroxyl group equivalent of phenolic resin refers to the phenolic hydroxyl group equivalent.

[0090] ·Softening point: Measurements were taken in accordance with the JIS K 7234 standard and the ring-sphere method. Specifically, an automatic softening point device (ASP-MG4, manufactured by Maytec Co., Ltd.) was used.

[0091] • Epoxy equivalent: Measurements were performed in accordance with JIS K 7236 standard, and the unit is expressed as "g / eq.". Specifically, an automatic potentiometric titrator (Hiranuma Sangyo Co., Ltd., COM-1600ST) was used, chloroform was used as the solvent, tetraethylammonium brominated acetate solution was added, and titration was performed with 0.1 mol / L perchloric acid-acetic acid solution.

[0092] ·Total chlorine content: Measurements were performed in accordance with JIS K 7243-3 standard, and the unit was expressed in "ppm". Specifically, diethylene glycol monobutyl ether was used as the solvent, and after adding a 1 mol / L potassium hydroxide 1,2-propanediol solution and heating, the sample was titrated with a 0.01 mol / L silver nitrate solution using an automatic potentiometric titrator (Hiranuma Sangyo Co., Ltd., COM-1700).

[0093] • Melt viscosity: The melt viscosity at 150°C was measured using an ICI viscosity analyzer (CV-1S, manufactured by Toa Kogyo Co., Ltd.).

[0094] • Relative permittivity and dielectric loss tangent: Measurements were performed in accordance with IPC-TM-650 2.5.5.9. Specifically, the samples were dried in an oven set to 105°C for 2 hours, cooled in a desiccator, and then evaluated by determining the relative permittivity and dielectric loss tangent at a frequency of 1 GHz using the capacitance method with a material analyzer manufactured by AGILENT Technologies.

[0095] • Copper foil peel strength and interlayer adhesion: The interlayer adhesion strength was measured in accordance with JIS C 6481, by peeling the material between the 7th and 8th layers.

[0096] • GPC (Gel Permeation Chromatography) measurement: A system consisting of a main unit (Tosoh Corporation, HLC-8220GPC) and columns (Tosoh Corporation, TSKgelG4000HXL, TSKgelG3000HXL, TSKgelG2000HXL) connected in series was used, with the column temperature set to 40°C. Tetrahydrofuran (THF) was used as the eluent at a flow rate of 1 mL / min, and a differential refractive index detector was used. For the measurement sample, 0.1 g of the sample was dissolved in 10 mL of THF, filtered through a microfilter, and 50 μL of the resulting sample was used. Data processing was performed using Tosoh Corporation's GPC-8020 Model II version 6.00.

[0097] ·ESI-MS: Mass spectrometry was performed using a mass spectrometer (Shimadzu Corporation, LCMS-2020) with acetonitrile and water as the mobile phases, by measuring the sample dissolved in acetonitrile.

[0098] The abbreviations used in the examples and comparative examples are as follows:

[0099] [Epoxy resin] E1: Epoxy resin obtained in Example 6 E2: Epoxy resin obtained in Example 7 E3: Epoxy resin obtained in Example 8 E4: Epoxy resin obtained in Example 9 E5: Epoxy resin obtained in Example 10 EH1: Epoxy resin obtained in Synthesis Example 4 EH2: Phenol-dicyclopentadiene type epoxy resin (manufactured by DIC Corporation, HP-7200H, epoxy equivalent 280, softening point 83°C, melt viscosity at 150°C 0.40 Pa·s)

[0100] [Hardening agent] P1: Phenolic resin obtained in Example 1 P2: Phenolic resin obtained in Example 2 P3: Phenolic resin obtained in Example 3 P4: Phenolic resin obtained in Example 4 P5: Phenolic resin obtained in Example 5 PH1: Phenolic resin obtained in Synthesis Example 1 PH2: Phenolic resin obtained in Synthesis Example 2 PH3: Aromatic modified phenol resin obtained in Synthesis Example 3 PH4: Phenol novolac resin (manufactured by Aica Kogyo Co., Ltd., Shownol BRG-557, hydroxyl group equivalent 105, softening point 80°C, melt viscosity at 150°C 0.30 Pa·s)

[0101] [Curing accelerator] C1:2E4MZ:2-Ethyl-4-methylimidazole (manufactured by Shikoku Chemicals Co., Ltd., Curesol 2E4MZ)

[0102] Synthesis Example 1 In a reaction apparatus consisting of a glass separable flask equipped with a stirrer, thermometer, nitrogen blowing tube, dropping funnel, and condenser, 500 parts of 2,6-xylenol and 7.3 parts of 47% BF3 ether complex were charged and heated to 100°C with stirring. While maintaining the same temperature, 67.6 parts of dicyclopentadiene (0.12 molars relative to 2,6-xylenol) were added dropwise over 1 hour. The reaction was further carried out at a temperature of 115-125°C for 4 hours, and 11 parts of calcium hydroxide were added. Then, 19 parts of 10% aqueous oxalic acid solution were added. After that, the mixture was heated to 160°C to dehydrate it, and then heated to 200°C under reduced pressure of 5 mmHg to evaporate and remove unreacted starting materials. 1320 parts of MIBK were added to dissolve the product, and 400 parts of 80°C warm water were added for washing, and the lower layer of water was separated and removed. Subsequently, MIBK was evaporated and removed by heating to 160°C under reduced pressure of 5 mmHg, yielding 164 parts of reddish-brown phenolic resin (PH1). The hydroxyl group equivalent was 195, and the softening point was 73°C. In GPC, Mw was 470, Mn was 440, the m=0 content was 2.8 area%, the m=1 content was 86.2 area%, and the m=2 or more content was 11.0 area%. The melt viscosity at 150°C was 0.05 Pa·s.

[0103] Synthesis Example 2 In a reaction apparatus similar to that used in Synthesis Example 1, 361 parts of ortho-cresol and 5.9 parts of 47% BF3 ether complex were charged and heated to 100°C with stirring. While maintaining the same temperature, 55.2 parts of dicyclopentadiene (0.13 molars relative to ortho-cresol) were added dropwise over 1 hour. The reaction was further carried out at 115-125°C for 4 hours, and 9 parts of calcium hydroxide were added. Then, 16 parts of 10% oxalic acid aqueous solution were added. After that, the mixture was heated to 160°C to dehydrate it, and then heated to 200°C under reduced pressure of 5 mmHg to evaporate and remove unreacted starting materials. 970 parts of MIBK were added to dissolve the product, and 290 parts of 80°C warm water were added to wash it, and the lower layer of water was separated and removed. Then, under reduced pressure of 5 mmHg, the mixture was heated to 160°C to evaporate and remove the MIBK, yielding 137 parts of reddish-brown phenolic resin (PH2). The hydroxyl group equivalent was 184, and the softening point was 78°C. In GPC, Mw was 460, Mn was 410, m=0 content was 0.8 area%, m=1 content was 75.5 area%, and m=2 or more content was 23.7 area%. The melt viscosity at 150°C was 0.07 Pa·s.

[0104] Synthesis Example 3 In a reaction apparatus similar to that used in Synthesis Example 1, 105 parts of phenol novolac resin (hydroxyl equivalent 105, softening point 130°C) and 0.1 parts of p-toluenesulfonic acid were charged, and the temperature was raised to 150°C. While maintaining the same temperature, 94 parts of styrene were added dropwise over 3 hours, and stirring was continued at the same temperature for another hour. Subsequently, the resin was dissolved in 500 parts of MIBK and washed five times with water at 80°C. MIBK was then removed by distillation under reduced pressure to obtain aromatically modified phenol novolac resin (PH3). The hydroxyl equivalent was 199, and the softening point was 110°C. The melt viscosity at 150°C was 0.18 Pa·s.

[0105] Example 1 In a reaction apparatus similar to that used in Synthesis Example 1, 100 parts of the phenolic resin (PH1) obtained in Synthesis Example 1, 1.0 part of p-toluenesulfonic acid monohydrate, and 25 parts of MIBK were charged and heated to 120°C while stirring. While maintaining the same temperature, 30 parts of divinylbenzene (Aldrich, 55% divinylbenzene, 45% ethylvinylbenzene) (0.45 times the molar amount relative to the phenolic resin) were added dropwise over 1 hour. The reaction was further carried out at a temperature of 120-130°C for 4 hours. 280 parts of MIBK were added to dissolve the product, neutralized with 1.3 parts of sodium bicarbonate, and washed with 90 parts of 80°C warm water. The lower layer of water was separated and removed. Subsequently, the mixture was heated to 180°C under reduced pressure of 5 mmHg to evaporate and remove the MIBK, yielding 123 parts of reddish-brown phenolic resin (P1). The hydroxyl group equivalent was 250, and the softening point was 81°C. Mass spectra were measured using ESI-MS (negative), and M-=375, 507, 629, 639, and 761 were identified. The GPC of the obtained phenolic resin (P1) is shown in Figure 1. In the GPC, Mw was 740, Mn was 540, the content of n=0 was 4.9 area%, the content of n=1 was 53.3 area%, and the content of n=2 or more was 41.8 area. The melt viscosity at 150°C was 0.13 Pa·s.

[0106] Example 2 In a reaction apparatus similar to that used in Synthesis Example 1, 100 parts of the phenolic resin (PH1) obtained in Synthesis Example 1, 1.0 part of p-toluenesulfonic acid monohydrate, and 25 parts of MIBK were charged and heated to 120°C while stirring. While maintaining the same temperature, 45 parts of divinylbenzene (Aldrich, 55% divinylbenzene, 45% ethylvinylbenzene) (0.67 molars relative to the phenolic resin) were added dropwise over 1 hour. The reaction was further carried out at a temperature of 120-130°C for 4 hours. 310 parts of MIBK were added to dissolve the product, neutralized with 1.3 parts of sodium bicarbonate, and washed with 100 parts of 80°C water. The lower layer of water was separated and removed. Subsequently, the mixture was heated to 180°C under reduced pressure of 5 mmHg to evaporate and remove the MIBK, yielding 139 parts of reddish-brown phenolic resin (P2). The hydroxyl group equivalent was 276, and the softening point was 71°C. Mass spectra measured by ESI-MS (negative) revealed M-=375, 507, 629, 639, and 761. GPC showed Mw = 800, Mn = 540, n=0 content = 6.5 area%, n=1 content = 51.1 area%, and n=2 or more content = 42.4 area%. The melt viscosity at 150°C was 0.09 Pa·s.

[0107] Example 3 In a reaction apparatus similar to that used in Synthesis Example 1, 80 parts of the phenolic resin (PH1) obtained in Synthesis Example 1, 0.8 parts of p-toluenesulfonic acid monohydrate, and 20 parts of MIBK were charged and heated to 120°C while stirring. While maintaining the same temperature, 48 parts of divinylbenzene (Aldrich, 55% divinylbenzene, 45% ethylvinylbenzene) (0.90 molar ratio to the phenolic resin) were added dropwise over 1 hour. The reaction was further carried out at a temperature of 120-130°C for 4 hours. 280 parts of MIBK were added to dissolve the product, neutralized with 1.1 parts of sodium bicarbonate, and washed with 90 parts of 80°C warm water. The lower layer of water was separated and removed. Subsequently, the mixture was heated to 180°C under reduced pressure of 5 mmHg to evaporate and remove the MIBK, yielding 120 parts of reddish-brown phenolic resin (P3). The hydroxyl group equivalent was 306, and the softening point was 68°C. Mass spectra measured by ESI-MS (negative) revealed M-=375, 507, 629, 639, and 761. GPC showed Mw = 910, Mn = 550, n=0 content = 7.5 area%, n=1 content = 48.9 area%, and n=2 or more content = 43.6 area. The melt viscosity at 150°C was 0.08 Pa·s.

[0108] Example 4 In a reaction apparatus similar to that used in Synthesis Example 1, 93 parts of the phenolic resin (PH1) obtained in Synthesis Example 1, 0.9 parts of p-toluenesulfonic acid monohydrate, and 23 parts of MIBK were charged and heated to 120°C while stirring. While maintaining the same temperature, 41.8 parts of divinylbenzene (Aldrich, 80% divinylbenzene, 20% ethylvinylbenzene) (0.90 molar ratio to the phenolic resin) were added dropwise over 1 hour. The reaction was further carried out at a temperature of 120-130°C for 4 hours. 290 parts of MIBK were added to dissolve the product, neutralized with 1.2 parts of sodium bicarbonate, and washed with 90 parts of 80°C warm water. The lower layer of water was separated and removed. Subsequently, the mixture was heated to 180°C under reduced pressure of 5 mmHg to evaporate and remove the MIBK, yielding 128 parts of reddish-brown phenolic resin (P4). The hydroxyl group equivalent was 281, and the softening point was 88°C. Mass spectra measured by ESI-MS (negative) revealed M-=375, 507, 629, 639, and 761. GPC showed Mw = 1400, Mn = 650, n=0 content = 3.1 area%, n=1 content = 43.3 area%, and n=2 or more content = 53.6 area%. The melt viscosity at 150°C was 0.33 Pa·s.

[0109] Example 5 In a reaction apparatus similar to that used in Synthesis Example 1, 100 parts of the phenolic resin (PH2) obtained in Synthesis Example 2, 1.0 part of p-toluenesulfonic acid monohydrate, and 25 parts of MIBK were charged and heated to 120°C while stirring. While maintaining the same temperature, 45 parts of divinylbenzene (Aldrich, 55% divinylbenzene, 45% ethylvinylbenzene) (0.45 times the molar amount relative to the phenolic resin) were added dropwise over 1 hour. The reaction was further carried out at a temperature of 120-130°C for 4 hours. 310 parts of MIBK were added to dissolve the product, neutralized with 1.3 parts of sodium bicarbonate, and washed with 100 parts of 80°C water. The lower layer of water was separated and removed. Subsequently, the mixture was heated to 180°C under reduced pressure of 5 mmHg to evaporate and remove the MIBK, yielding 140 parts of reddish-brown phenolic resin (P5). The hydroxyl group equivalent was 255, and the softening point was 77°C. Mass spectra measured by ESI-MS (negative) revealed M-=347, 479, 587, 611, and 719. GPC showed Mw = 780, Mn = 500, n=0 content = 3.0 area%, n=1 content = 45.1 area%, and n=2 or more content = 51.9 area%. The melt viscosity at 150°C was 0.20 Pa·s.

[0110] Example 6 In a reaction apparatus equipped with a stirrer, thermometer, nitrogen blowing tube, dropping funnel, and condenser, 100 parts of the phenol resin (P1) obtained in Example 1, 185 parts of epichlorohydrin, and 55 parts of diethylene glycol dimethyl ether were added and heated to 65°C. Under reduced pressure of 125 mmHg, 35.9 parts of 49% sodium hydroxide aqueous solution were added dropwise over 4 hours while maintaining a temperature of 63-67°C. During this time, the epichlorohydrin was azeotropically mixed with water, and the resulting water was sequentially removed from the system. After the reaction was complete, the epichlorohydrin was recovered under conditions of 5 mmHg and 180°C, and the product was dissolved by adding 290 parts of MIBK. Then, 90 parts of water were added to dissolve the by-product sodium chloride, and the mixture was allowed to stand to separate and remove the lower layer of saline solution. After neutralization with phosphoric acid aqueous solution, the resin solution was washed with water until the water wash was neutral, and then filtered. Under reduced pressure of 5 mmHg, the mixture was heated to 180°C to remove MIBK, yielding 117 parts of a reddish-brown epoxy resin (E1). The epoxy equivalent was 315, the total chlorine content was 590 ppm, and the softening point was 62°C. The GPC of the obtained epoxy resin (E1) is shown in Figure 2. In the GPC, Mw was 890, Mn was 580, the k=0 content was 3.8 area%, the k=1 content was 50.7 area%, and the k=2 or higher content was 45.5 area%. The melt viscosity at 150°C was 0.18 Pa·s.

[0111] Example 7 In a reaction apparatus equipped with a stirrer, thermometer, nitrogen blowing tube, dropping funnel, and condenser, 102 parts of the phenol resin (P2) obtained in Example 2, 171 parts of epichlorohydrin, and 51 parts of diethylene glycol dimethyl ether were added and heated to 65°C. Under reduced pressure of 125 mmHg, 33.3 parts of 49% sodium hydroxide aqueous solution were added dropwise over 4 hours while maintaining a temperature of 63-67°C. During this time, the epichlorohydrin was azeotropically mixed with water, and the resulting water was sequentially removed from the system. After the reaction was complete, the epichlorohydrin was recovered under conditions of 5 mmHg and 180°C, and the product was dissolved by adding 290 parts of MIBK. Then, 90 parts of water were added to dissolve the by-product sodium chloride, and the mixture was allowed to stand to separate and remove the lower layer of saline solution. After neutralization with phosphoric acid aqueous solution, the resin solution was washed with water until the rinse solution was neutral, and then filtered. Under reduced pressure of 5 mmHg, the mixture was heated to 180°C to remove MIBK, yielding 118 parts of a reddish-brown epoxy resin (E2). The epoxy equivalent was 345, the total chlorine content was 510 ppm, and the softening point was 57°C. The Mw in the GPC was 1180, the Mn was 590, the k=0 content was 5.5 area%, the k=1 content was 48.0 area%, and the k=2 or higher content was 46.5 area%. The melt viscosity at 150°C was 0.14 Pa·s.

[0112] Example 8 In a reaction apparatus equipped with a stirrer, thermometer, nitrogen blowing tube, dropping funnel, and condenser, 101 parts of the phenol resin (P3) obtained in Example 3, 153 parts of epichlorohydrin, and 46 parts of diethylene glycol dimethyl ether were added and heated to 65°C. Under reduced pressure of 125 mmHg, 29.7 parts of 49% sodium hydroxide aqueous solution were added dropwise over 4 hours while maintaining a temperature of 63-67°C. During this time, the epichlorohydrin was azeotropically mixed with water, and the resulting water was sequentially removed from the system. After the reaction was complete, the epichlorohydrin was recovered under conditions of 5 mmHg and 180°C, and the product was dissolved by adding 280 parts of MIBK. Then, 80 parts of water were added to dissolve the by-product sodium chloride, and the mixture was allowed to stand to separate and remove the lower layer of saline solution. After neutralization with phosphoric acid aqueous solution, the resin solution was washed with water until the rinse solution was neutral, and then filtered. Under reduced pressure of 5 mmHg, the mixture was heated to 180°C to remove MIBK, yielding 113 parts of a reddish-brown epoxy resin (E3). The epoxy equivalent was 373, the total chlorine content was 530 ppm, and the resin was semi-solid at room temperature. The Mw in the GPC was 1670, Mn was 610, the k=0 isomer content was 6.1 area%, the k=1 isomer content was 45.5 area%, and the k=2 or higher isomer content was 48.4 area%. The melt viscosity at 150°C was 0.15 Pa·s.

[0113] Example 9 In a reaction apparatus equipped with a stirrer, thermometer, nitrogen blowing tube, dropping funnel, and condenser, 101 parts of the phenol resin (P4) obtained in Example 4, 166 parts of epichlorohydrin, and 50 parts of diethylene glycol dimethyl ether were added and heated to 65°C. Under reduced pressure of 125 mmHg, 32.3 parts of 49% sodium hydroxide aqueous solution were added dropwise over 4 hours while maintaining a temperature of 63-67°C. During this time, the epichlorohydrin was azeotropically mixed with water, and the resulting water was sequentially removed from the system. After the reaction was complete, the epichlorohydrin was recovered under conditions of 5 mmHg and 180°C, and the product was dissolved by adding 280 parts of MIBK. Then, 90 parts of water were added to dissolve the by-product sodium chloride, and the mixture was allowed to stand to separate and remove the lower layer of saline solution. After neutralization with phosphoric acid aqueous solution, the resin solution was washed with water until the rinse solution was neutral, and then filtered. Under reduced pressure of 5 mmHg, the mixture was heated to 180°C to remove MIBK, yielding 118 parts of a reddish-brown epoxy resin (E4). The epoxy equivalent was 351, the total chlorine content was 550 ppm, and the softening point was 77°C. The Mw in the GPC was 2080, the Mn was 690, the k=0 isomer content was 2.6 area%, the k=1 isomer content was 40.0 area%, and the k=2 or more isomer content was 57.4 area%. The melt viscosity at 150°C was 0.44 Pa·s.

[0114] Example 10 In a reaction apparatus equipped with a stirrer, thermometer, nitrogen blowing tube, dropping funnel, and condenser, 100 parts of the phenol resin (P5) obtained in Example 5, 181 parts of epichlorohydrin, and 54 parts of diethylene glycol dimethyl ether were added and heated to 65°C. Under reduced pressure of 125 mmHg, 35.2 parts of 49% sodium hydroxide aqueous solution were added dropwise over 4 hours while maintaining a temperature of 63-67°C. During this time, the epichlorohydrin was azeotropically mixed with water, and the resulting water was sequentially removed from the system. After the reaction was complete, the epichlorohydrin was recovered under conditions of 5 mmHg and 180°C, and the product was dissolved by adding 290 parts of MIBK. Then, 90 parts of water were added to dissolve the by-product sodium chloride, and the mixture was allowed to stand to separate and remove the lower layer of saline solution. After neutralization with phosphoric acid aqueous solution, the resin solution was washed with water until the water wash was neutral, and then filtered. Under reduced pressure of 5 mmHg, the mixture was heated to 180°C to remove MIBK, yielding 116 parts of a reddish-brown epoxy resin (E5). The epoxy equivalent was 323, the total chlorine content was 580 ppm, and the softening point was 70°C. The Mw in the GPC was 1200, Mn was 550, the k=0 content was 2.5 area%, the k=1 content was 42.0 area%, and the k=2 or higher content was 55.5 area%. The melt viscosity at 150°C was 0.32 Pa·s.

[0115] Synthesis Example 4 In a reaction apparatus similar to that of Example 6, 150 parts of the phenol resin (P1) obtained in Synthesis Example 1, 356 parts of epichlorohydrin, and 107 parts of diethylene glycol dimethyl ether were added and heated to 65°C. Under reduced pressure of 125 mmHg, 69.1 parts of 49% sodium hydroxide aqueous solution were added dropwise over 4 hours while maintaining a temperature of 63-67°C. During this time, the epichlorohydrin was azeotropically mixed with water, and the resulting water was sequentially removed from the system. After the reaction was complete, the epichlorohydrin was recovered under conditions of 5 mmHg and 180°C, and the product was dissolved by adding 450 parts of MIBK. Then, 140 parts of water were added to dissolve the by-product sodium chloride, and the mixture was allowed to stand to separate and remove the lower layer of saline solution. After neutralization with phosphoric acid aqueous solution, the resin solution was washed with water until the rinse solution was neutral, and then filtered. Under reduced pressure of 5 mmHg, the mixture was heated to 180°C to remove MIBK, yielding 183 parts of a reddish-brown dicyclopentadiene-type epoxy resin (EH1). The epoxy equivalent was 261, the total chlorine content was 710 ppm, and the softening point was 55°C. The Mw in the GPC was 670, the Mn was 570, the k=0 isomer content was 2.3 area%, the k=1 isomer content was 73.1 area%, and the k=2 or higher isomer content was 24.6 area%. The melt viscosity at 150°C was 0.10 Pa·s.

[0116] Example 11 An epoxy resin composition varnish was obtained by mixing 100 parts epoxy resin (E1) as the epoxy resin, 33 parts phenolic resin (PH4) as the curing agent, and 0.40 parts C1 as the curing accelerator, and dissolving them in a mixed solvent prepared with MEK, propylene glycol monomethyl ether, and N,N-dimethylformamide. The obtained epoxy resin composition varnish was impregnated into glass cloth (manufactured by Nitto Boseki Co., Ltd., WEA 7628 XS13, 0.18 mm thick). The impregnated glass cloth was dried in a hot air circulating oven at 150°C for 9 minutes to obtain a prepreg. Eight of the obtained prepregs were stacked with copper foil (manufactured by Mitsui Mining & Smelting Co., Ltd., 3EC-III, 35 μm thick) on the top and bottom, and vacuum pressing was performed at 2 MPa under the temperature conditions of 130°C for 15 minutes + 190°C for 80 minutes to obtain a 1.6 mm thick laminate. The results of the copper foil peel strength and interlayer adhesion strength of the laminate are shown in Table 1.

[0117] Furthermore, the obtained prepreg was loosened and sieved to produce a 100-mesh pass prepreg powder. The obtained prepreg powder was placed in a fluororesin mold and subjected to a vacuum press at 2 MPa under the temperature conditions of 130°C for 15 minutes + 190°C for 80 minutes to obtain a 50 mm square x 2 mm thick test specimen. The relative permittivity and dielectric loss tangent of the test specimen are shown in Table 1.

[0118] Examples 12-32 and Comparative Examples 1-8 The mixtures were prepared using the proportions (parts) shown in Tables 1-4, and the same procedure as in Example 11 was followed to obtain laminates and test specimens. The amount of curing accelerator used was sufficient to adjust the varnish gel time to approximately 300 seconds. The same test as in Example 11 was performed, and the results are shown in Tables 1-4.

[0119] [Table 1]

[0120] [Table 2]

[0121] [Table 3]

[0122] [Table 4]

[0123] As is clear from these results, the polyvalent hydroxy resins and epoxy resins obtained in the examples exhibit very good low viscosity, and resin compositions containing them can provide cured resin products that exhibit very good low dielectric properties while maintaining an adhesiveness of 1.0 kN / m or higher, which is practically acceptable. Industrial application fields

[0124] The polyvalent hydroxy resin, epoxy resin, or epoxy resin composition of the present invention can be used in paints, civil engineering adhesives, casting, electrical and electronic materials, film materials, etc., and is particularly useful in applications of printed circuit boards, which are one type of electrical and electronic material.

Claims

1. A polyvalent hydroxy resin characterized by being represented by the following general formula (1). 【Chemistry 1】 (Here, R １ R independently represents an alkyl group having 1 to 8 carbon atoms. ２ R independently represents a hydrogen atom, a group represented by formula (2), or a group represented by formula (3), and has at least a group represented by formula (2) and a group represented by formula (3). ３ (Each represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. i is an integer from 0 to 2. n1 indicates the number of repetitions, with an average value from 0 to 5.)

2. The aforementioned R １ The polyvalent hydroxy resin according to claim 1, wherein is a methyl group and i is 1 or 2.

3. A method for producing a polyvalent hydroxy resin, characterized by reacting a polyvalent hydroxy resin (a) represented by the following general formula (4) with an aromatic vinyl compound (b) represented by the following general formulas (5a) and (5b). 【Chemistry 2】 (Here, R １ (Each represents an alkyl group with 1 to 8 carbon atoms. i is an integer from 0 to 2. m represents the number of repeats, with an average value from 0 to 5.) 【Transformation 3】 (Here, R ３ (This represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms.)

4. A method for producing a polyvalent hydroxy resin according to claim 3, characterized in that, in the presence of an acid catalyst, 0.05 to 2.0 moles of the aromatic vinyl compound (b) per mole of phenolic hydroxyl groups of the polyvalent hydroxy resin (a) are reacted at a reaction temperature of 50 to 200°C.

5. An epoxy resin characterized by being represented by the following general formula (6). 【Chemistry 4】 (Here, R １ independently represents an alkyl group having 1 to 8 carbon atoms, and R ２ independently represents a hydrogen atom, a group represented by the formula (2), or a group represented by the formula (3), and has at least a group represented by the formula (2) and a group represented by the formula (3). R ３ independently represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms. i is an integer of 0 to 2. n3 represents the number of repetitions, and the average value thereof is a number of 0 to 5.)

6. A method for producing epoxy resin, characterized by reacting 1 to 20 moles of epihalohydrin with 1 mole of phenolic hydroxyl groups of a polyvalent hydroxyl resin represented by general formula (1) as described in claim 1, in the presence of an alkali metal hydroxide.

7. An epoxy resin composition comprising an epoxy resin and a curing agent, characterized in that it requires the polyvalent hydroxy resin described in claim 1 and / or the epoxy resin described in claim 5.

8. A prepreg characterized by using the epoxy resin composition described in claim 7.

9. A laminate characterized by using the epoxy resin composition described in claim 7.

10. A printed circuit board characterized by using the epoxy resin composition described in claim 7.

11. A cured product obtained by curing the epoxy resin composition according to claim 7.

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