Method for producing modified epoxy resin

Abstract

To provide a method for producing a modified epoxy resin giving a cured product having high adhesiveness and high mechanical strength together with a low dielectric constant and dielectric loss tangent.SOLUTION: The method for producing a modified epoxy resin comprises reacting an aromatic ester compound represented by general formula (1) and / or a carbonate ester compound represented by general formula (3) with an epoxy resin in the presence of a catalyst, wherein the catalyst is a carboxylate of a quaternary phosphonium salt.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing a modified epoxy resin that gives a cured product having a low dielectric loss tangent and excellent adhesiveness and mechanical strength. [Background technology]

[0002] Epoxy resin compositions containing an epoxy resin and its curing agent as essential components exhibit excellent heat resistance and insulating properties in the cured product, and are therefore widely used in electronic component applications such as semiconductors and multilayer printed circuit boards. In the field of electronic component applications, particularly in the field of insulating materials for multilayer printed circuit boards, the speed and frequency of signals in various electronic devices have been increasing in recent years. However, as signal speeds and frequencies increase, it is becoming increasingly difficult to obtain a low dielectric loss tangent. At the same time, high adhesiveness and mechanical strength are required from the standpoint of reliability.

[0003] Therefore, it is desired to provide a thermosetting resin composition that can give a cured product that exhibits high adhesiveness and high mechanical strength as well as a low dielectric loss tangent, even for signals with higher speeds and frequencies.

[0004] Regarding the reduction of the dielectric constant of epoxy resins, Patent Documents 1 and 2 disclose modified epoxy resins obtained by reacting epoxy resins with diester compounds, and their cured products. In these documents, polarization is suppressed by esterifying the secondary hydroxyl groups produced by the reaction of epoxy resins with phenolic compounds. However, Patent Documents 1 and 2 only discuss the use of N,N'-dimethylaminopyridine, 2-ethyl-4(5)-methylimidazole, or tetrabutylammonium bromide as catalysts for the reaction of epoxy resins with diester compounds, and do not consider the adhesiveness or mechanical strength of these compounds.

[0005] Patent Document 3 discloses a modified epoxy resin obtained by reacting an epoxy resin with a carbonate ester compound. This modified epoxy resin is thought to suppress polarization because it does not produce secondary hydroxyl groups, which are produced by the reaction of an epoxy resin with a phenolic compound. However, Patent Document 3 only discusses quaternary onium salt catalysts, crown ether complex catalysts, tertiary amine catalysts, or tertiary phosphine catalysts as catalysts used in the reaction of the epoxy resin with the carbonate ester compound, and does not consider dielectric properties, adhesiveness, or mechanical strength. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 3642353 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-089165 [Patent Document 3] Japanese Patent Application Publication No. 11-302369 Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, an object of the present invention is to provide a method for producing a modified epoxy resin which gives a cured product having low dielectric properties as well as excellent adhesive properties and mechanical strength, and is useful for applications such as lamination, molding, casting, and adhesion. [Means for solving the problem]

[0008] In order to solve the above problems, the present inventors have conducted extensive research into catalysts to be used in the reaction of an aromatic ester compound and / or a carbonate ester compound with an epoxy resin. As a result, they have found that a cured product obtained by curing a resin composition containing a modified epoxy resin produced using a catalyst with a specific structure has excellent dielectric properties, adhesiveness and mechanical strength, and have completed the present invention.

[0009] That is, the present invention provides a method for producing a modified epoxy resin by reacting an aromatic ester compound represented by the following general formula (1) and / or a carbonate ester compound represented by the following general formula (3) with an epoxy resin in the presence of a catalyst, wherein the catalyst is a carboxylic acid salt of a quaternary phosphonium salt. [ka] In formula (1), A is an aromatic ring selected from the group consisting of a benzene ring, a naphthalene ring, a biphenyl ring, and a bisphenyl ring, and these aromatic rings may have a substituent, and may have an oxygen atom, a phosphorus atom, a nitrogen atom, and / or a sulfur atom. 1 and X 2 is an acyloxy group or a hydroxyl group represented by the following formula (2), and at least one is an acyloxy group. [ka] In equation (2), R 1 is a methyl group or a phenyl group. * indicates the bonding position. [ka] In equation (3), R 2 and R 3 are independently a group selected from an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, and an alkynyl group having 2 to 12 carbon atoms.

[0010] The aromatic ester compound is preferably a phosphorus compound represented by the following general formula (4) and / or general formula (5). [ka] In formula (4) and formula (5), B is a benzene ring or a naphthalene ring, which may have a hydrocarbon group having 1 to 12 carbon atoms as a substituent, and the substituent may have a hetero element. 4 and R 5is a hydrocarbon group having 1 to 12 carbon atoms which may have a heteroatom, and together with the phosphorus atom, R 4 , R 5 may be bonded to form a cyclic structure. n is 0 or 1. X 1 and X 2 has the same meaning as general formula (1).

[0011] The carbonate ester compound is preferably diphenyl carbonate represented by the following general formula (6). [ka]

[0012] The carboxylic acid salt of the quaternary phosphonium salt preferably contains a salt of a phosphonium cation represented by the following general formula (7) and an anionic residue of a carboxylic acid. [ka] In equation (7), R 8 , R 9 , R 10 and R 11 are independently a group selected from alkyl groups having 1 to 12 carbon atoms and phenyl groups which may have a substituent on the aromatic ring. [Effects of the Invention]

[0013] The present invention provides a modified epoxy resin and resin composition having excellent dielectric properties, adhesiveness, and mechanical strength. The modified epoxy resin has excellent dielectric properties, adhesiveness, and mechanical strength, and can be suitably used in applications requiring a low dielectric constant, low dielectric dissipation factor, adhesiveness, and mechanical strength, such as multilayer printed wiring boards, laminates for electric and electronic circuits (e.g., capacitors), adhesives (e.g., film adhesives, liquid adhesives), semiconductor encapsulation materials, underfill materials, interchip fill materials for 3D-LSIs, insulating sheets, prepregs, and heat dissipation substrates. [Brief explanation of the drawings]

[0014] [Figure 1]1 shows GPC charts of modified epoxy resins of Example 1 and Comparative Example 1. The solid line indicates Example 1 (Resin R1), and the dashed line indicates Comparative Example 1 (Resin HR1). DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments and examples, and can be implemented with any modifications within the scope of the claims of the present invention and their equivalents.

[0016] The modified epoxy resin of the present invention is obtained by reacting an aromatic ester compound represented by the following general formula (1) and / or a carbonate ester compound represented by the following general formula (3) with an epoxy resin in the presence of a carboxylic acid salt of a quaternary phosphonium salt.

[0017] The weight-average molecular weight (Mw) of the modified epoxy resin obtained by the method of the present invention is preferably 500 or more and 100,000 or less. Here, if Mw is less than 500, there is a risk that the structure that improves the dielectric properties will not be fully introduced. If Mw is greater than 100,000, compatibility may decrease and the resin may be difficult to handle. Furthermore, from the viewpoint of improving the film-forming properties of the modified epoxy resin, Mw is preferably 5,000 or more, more preferably 10,000 or more, and even more preferably 15,000 or more. From the viewpoint of improving compatibility and handleability, Mw is more preferably 160,000 or less, even more preferably 120,000 or less, and particularly preferably 80,000 or less. For substrate applications where the resin is used by impregnation into a substrate, Mw may be 10,000 or less, more preferably 5,000 or less. The Mw of the modified epoxy resin can be measured by gel permeation chromatography (GPC) as described in the examples.

[0018] Furthermore, if the epoxy equivalent is 200 to 100,000 g / eq., the modified epoxy resin can participate in the curing reaction and be incorporated into a crosslinked structure. Therefore, the epoxy equivalent of the modified epoxy resin obtained by the method of the present invention is preferably 300 to 40,000, more preferably 400 to 30,000, and even more preferably 440 to 20,000. On the other hand, for substrate applications where the resin is impregnated into a substrate, good impregnation properties are required, so a low epoxy equivalent is preferable, i.e., 280 to 10,000, more preferably 280 to 5,000, and even more preferably 280 to 3,000. The lower limit in this case can also be changed as appropriate within the above numerical range.

[0019] Here, the aromatic ester compound represented by the general formula (1) is X 1 and X 2 and a monoester compound in which one is an acyloxy group and the other is a hydroxyl group, and the mixture may be a diester compound or a monoester compound, or a mixture containing a diester compound and / or a monoester compound. 1 and X 2 A diphenol compound in which both X and X are hydroxyl groups may be included, but the amount is preferably 50 mol % or less, more preferably 30 mol % or less. In other words, the amount of diester compounds and / or monoester compounds in the mixture is preferably 50 mol % or more, more preferably 70 mol % or more. A diester-based compound containing a diester compound as the main component is preferred, and the diester-based compound is preferably a compound containing X as the main component. 1 and X 2 It is preferable that both of the above are acyloxy groups in the diester compound, or that the main component (50 mol % or more) is a diester compound (mixture). If the content of monoester compounds or diphenol compounds is high, the acylation rate will be low. [ka]

[0020] In formula (1), A is an aromatic ring selected from the group consisting of a benzene ring, a naphthalene ring, a biphenyl ring, and a bisphenyl ring, and these aromatic rings may have a substituent, and may have an oxygen atom, a phosphorus atom, a nitrogen atom, and / or a sulfur atom.

[0021] Examples of A include, but are not limited to, the following formulas (a-1) to (a-20). These aromatic rings may be substituted with a hydrocarbon group having 1 to 12 carbon atoms as a substituent, and may have an oxygen atom, a phosphorus atom, a nitrogen atom, and / or a sulfur atom. In particular, examples of the substituent containing a phosphorus atom include the phosphorus-containing groups described below. [ka]

[0022] Examples of the hydrocarbon group having 1 to 12 carbon atoms (which may have an oxygen atom) substituting A include an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, an aralkyl group having 7 to 12 carbon atoms, and an aralkyloxy group having 7 to 12 carbon atoms.

[0023] The alkyl group having 1 to 12 carbon atoms may be linear, branched, or cyclic, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, a t-pentyl group, a cyclopentyl group, an n-hexyl group, an isohexyl group, a cyclohexyl group, an n-heptyl group, a cycloheptyl group, a methylcyclohexyl group, an n-octyl group, a cyclooctyl group, an n-nonyl group, a 3,3,5-trimethylcyclohexyl group, an n-decyl group, a cyclodecyl group, an n-undecyl group, an n-dodecyl group, a cyclododecyl group, a benzyl group, a methylbenzyl group, a dimethylbenzyl group, a trimethylbenzyl group, a naphthylmethyl group, a phenethyl group, and a 2-phenylisopropyl group.

[0024] Examples of the alkoxy group having 1 to 12 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, a t-butoxy group, an n-pentoxy group, an isopentoxy group, a neopentoxy group, a t-pentoxy group, a cyclopentoxy group, an n-hexyloxy group, an isohexyloxy group, a cyclohexyloxy group, an n-heptoxy group, a cycloheptoxy group, and a methylcyclohexyloxy group. , n-octyloxy group, cyclooctyloxy group, n-nonyloxy group, 3,3,5-trimethylcyclohexyloxy group, n-decyloxy group, cyclodecyloxy group, n-undecyloxy group, n-dodecyloxy group, cyclododecyloxy group, benzyloxy group, methylbenzyloxy group, dimethylbenzyloxy group, trimethylbenzyloxy group, naphthylmethoxy group, phenethyloxy group, 2-phenylisopropoxy group, and the like.

[0025] Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, an ethylphenyl group, a styryl group, a xylyl group, an n-propylphenyl group, an isopropylphenyl group, a mesityl group, an ethynylphenyl group, a naphthyl group, and a methylnaphthyl group.

[0026] Examples of the aryloxy group having 6 to 12 carbon atoms include a phenoxy group, a tolyloxy group, a xylyloxy group, a naphthyloxy group, and a biphenyloxy group.

[0027] Examples of the aralkyl group having 7 to 12 carbon atoms include a benzyl group, a methylbenzyl group, a dimethylbenzyl group, a trimethylbenzyl group, a phenethyl group, a 2-phenylisopropyl group, and a naphthylmethyl group.

[0028] Examples of the aralkyloxy group having 7 to 12 carbon atoms include a benzyloxy group, a methylbenzyloxy group, a dimethylbenzyloxy group, a trimethylbenzyloxy group, a phenethyloxy group, a 1-phenylethyloxy group, a 2-phenylisopropyloxy group, and a naphthylmethyloxy group.

[0029] Preferred examples of A include a structure containing a benzene ring, a methyl-substituted benzene ring, a 1-phenylethyl-substituted benzene ring, a naphthalene ring, a methyl-substituted naphthalene ring, or a 1-phenylethyl-substituted naphthalene ring. For applications requiring higher solubility, A preferably contains a benzene ring, a methyl-substituted benzene ring, or a 1-phenylethyl-substituted benzene ring, and for applications requiring higher flame retardancy and heat resistance, A preferably contains a naphthalene ring, a methyl-substituted naphthalene ring, or a 1-phenylethyl-substituted naphthalene ring.

[0030] In formula (1), X 1 and X 2 is an acyloxy group or a hydroxyl group represented by the following formula (2), and at least one is an acyloxy group. [ka] In equation (2), R 1 is a methyl group or a phenyl group. * indicates the bonding position.

[0031] By reacting an aromatic ester compound represented by general formula (1) with an epoxy resin, the epoxy group of the epoxy resin reacts (addition reaction) with the acyloxy group of the aromatic ester compound. A new acyloxy group is generated by addition of the dissociated acyl group to the new secondary hydroxyl group generated during the reaction. Therefore, the final reaction product of the reaction between the aromatic ester compound represented by general formula (1) and the epoxy resin contains an acyloxy group, resulting in a modified epoxy resin. The modified epoxy resin of the present invention has low polarity and good low dielectric properties due to the inclusion of the acyloxy group represented by formula (2).

[0032] In order to impart flame retardancy to the modified epoxy resin, the aromatic ester compound is preferably a phosphorus compound represented by the following general formula (4) and / or general formula (5). [ka]

[0033] In formula (4) and formula (5), B is a benzene ring or a naphthalene ring, which may have a hydrocarbon group having 1 to 12 carbon atoms as a substituent, and the substituent may have a hetero element. 4 and R 5 is a hydrocarbon group having 1 to 12 carbon atoms which may have a heteroatom, and together with the phosphorus atom, R 4 , R 5 may be bonded to form a cyclic structure. n is 0 or 1. X 1 and X 2 has the same meaning as general formula (1).

[0034] In formula (4) and formula (5), examples of the hydrocarbon group having 1 to 12 carbon atoms that substitutes the structure of B include an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an aralkyl group having 7 to 12 carbon atoms.

[0035] For example, the alkyl group having 1 to 12 carbon atoms may be linear, branched, or cyclic, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, a t-pentyl group, a cyclopentyl group, an n-hexyl group, an isohexyl group, a cyclohexyl group, an n-heptyl group, a cycloheptyl group, a methylcyclohexyl group, an n-octyl group, a cyclooctyl group, an n-nonyl group, a 3,3,5-trimethylcyclohexyl group, an n-decyl group, a cyclodecyl group, an n-undecyl group, an n-dodecyl group, a cyclododecyl group, a benzyl group, a methylbenzyl group, a dimethylbenzyl group, a trimethylbenzyl group, a naphthylmethyl group, a phenethyl group, and a 2-phenylisopropyl group.

[0036] Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a tolyl group, an ethylphenyl group, a xylyl group, an n-propylphenyl group, an isopropylphenyl group, a mesityl group, a naphthyl group, and a methylnaphthyl group.

[0037] Examples of the aralkyl group having 7 to 12 carbon atoms include a benzyl group, a methylbenzyl group, a dimethylbenzyl group, a trimethylbenzyl group, a phenethyl group, a 2-phenylisopropyl group, and a naphthylmethyl group.

[0038] The phosphorus-containing group is preferably a phosphorus-containing group represented by the following formula (b-1) or (b-2). [ka]

[0039] In the formula, R 6 and R 7 are each preferably independently a hydrogen atom or a hydrocarbon group having 1 to 11 carbon atoms. Examples of the hydrocarbon group having 1 to 11 carbon atoms include a methyl group, an ethyl group, a t-butyl group, a cyclohexyl group, a phenyl group, a tolyl group, and a benzyl group, and are preferably a hydrogen atom, a methyl group, a phenyl group, or a benzyl group.

[0040] Examples of phosphorus-containing groups other than those represented by formula (b-1) or (b-2) include, but are not limited to, phosphorus-containing groups represented by the following formulas (c-1) to (c-10). [ka]

[0041] The phosphorus content of the flame-retardant modified epoxy resin is preferably 1.0 to 6.0% by mass. If the phosphorus content is less than 1.0% by mass, the improvement in flame retardancy tends to be insufficient. If the phosphorus content exceeds 6.0% by mass, the solvent solubility tends to decrease. A phosphorus content of 1.5 to 5.0% by mass is more preferable.

[0042] The starting aromatic ester compound used in the present invention can be obtained, for example, by acylation of a bifunctional phenol compound by a condensation reaction with an acid anhydride of an organic acid, a halide of an organic acid, or an organic acid. Here, the bifunctional phenol compound is a compound represented by the formula (1) above, 1 and X 2and hydroxyl groups.

[0043] Here, the carbonate compound is represented by the following general formula (3). [ka]

[0044] In equation (3), R 2 and R 3 are independently a group selected from an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, and an alkynyl group having 2 to 12 carbon atoms.

[0045] The alkyl group having 1 to 12 carbon atoms may be linear, branched, or cyclic, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, a t-pentyl group, a cyclopentyl group, an n-hexyl group, an isohexyl group, a cyclohexyl group, an n-heptyl group, a cycloheptyl group, a methylcyclohexyl group, an n-octyl group, a cyclooctyl group, an n-nonyl group, a 3,3,5-trimethylcyclohexyl group, an n-decyl group, a cyclodecyl group, an n-undecyl group, an n-dodecyl group, a cyclododecyl group, a benzyl group, a methylbenzyl group, a dimethylbenzyl group, a trimethylbenzyl group, a naphthylmethyl group, a phenethyl group, and a 2-phenylisopropyl group.

[0046] Examples of the alkoxy group having 1 to 12 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, a t-butoxy group, an n-pentoxy group, an isopentoxy group, a neopentoxy group, a t-pentoxy group, a cyclopentoxy group, an n-hexyloxy group, an isohexyloxy group, a cyclohexyloxy group, an n-heptoxy group, a cycloheptoxy group, and a methylcyclohexyloxy group. , n-octyloxy group, cyclooctyloxy group, n-nonyloxy group, 3,3,5-trimethylcyclohexyloxy group, n-decyloxy group, cyclodecyloxy group, n-undecyloxy group, n-dodecyloxy group, cyclododecyloxy group, benzyloxy group, methylbenzyloxy group, dimethylbenzyloxy group, trimethylbenzyloxy group, naphthylmethoxy group, phenethyloxy group, 2-phenylisopropoxy group, and the like.

[0047] Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, an ethylphenyl group, a styryl group, a xylyl group, an n-propylphenyl group, an isopropylphenyl group, a mesityl group, an ethynylphenyl group, a naphthyl group, and a methylnaphthyl group.

[0048] Examples of alkenyl groups having 2 to 12 carbon atoms include vinyl, 1-propenyl, 2-propenyl, 1-methylvinyl, 1-butenyl, 2-butenyl, 3-butenyl, 1,3-butadienyl, cyclohexenyl, cyclohexadienyl, cinnamyl, and naphthylvinyl groups.

[0049] Examples of the alkynyl group having 2 to 12 carbon atoms include an ethynyl group, a 1-propynyl group, a 2-propynyl group, a 1-butynyl group, a 2-butynyl group, a 3-butynyl group, a 1,3-butadienyl group, a phenylethynyl group, and a naphthylethynyl group.

[0050] The modified epoxy resin of the present invention does not increase secondary hydroxyl groups in the structure during modification, and therefore has low polarity and good low dielectric properties.

[0051] In order to impart low dielectric properties to the modified epoxy resin, the carbonate ester compound is preferably diphenyl carbonate represented by the following general formula (6). [ka] Regarding the reaction mechanism between an epoxy resin and a carbonate ester compound, for example, the reaction between an epoxy resin and diphenyl carbonate of formula (6) is considered to be a mechanism in which diphenyl carbonate dissociates into phenol and undergoes a polycondensation reaction with the epoxy group, not the secondary hydroxyl group, of the epoxy resin.

[0052] The epoxy resin used in the present invention may be, for example, an epoxy resin obtained by reacting a phenol compound with an epihalohydrin in the presence of an alkali metal compound.

[0053] Examples of epihalohydrins include epichlorohydrin and epibromohydrin.

[0054] Examples of alkali metal compounds include alkali metal hydroxides such as sodium hydroxide, lithium hydroxide, and potassium hydroxide; alkali metal salts such as sodium carbonate, sodium bicarbonate, sodium chloride, lithium chloride, and potassium chloride; alkali metal alkoxides such as sodium methoxide and sodium ethoxide; alkali metal salts of organic acids such as sodium acetate and sodium stearate; alkali metal phenoxides, sodium hydride, and lithium hydride. The amount used is 0.80 to 1.20 times, preferably 0.85 to 1.05 times, the molar ratio of the functional group (hydroxyl group) in the phenol compound. Less than this amount may result in a large amount of residual hydrolyzable chlorine. The alkali metal compound is used in the form of an aqueous solution, an alcohol solution, or a solid.

[0055] In the epoxidation reaction, an excess amount of epihalohydrin is used relative to the phenol compound. Typically, 1.5 to 15 moles of epihalohydrin are used per mole of functional groups in the phenol compound, preferably 2 to 10 moles, and more preferably 5 to 8 moles. If the amount is greater than this, production efficiency decreases, and if it is less than this, the amount of high-molecular-weight epoxy resin produced increases, making it unsuitable as a raw material in some cases.

[0056] The epoxidation reaction is usually carried out at a temperature of 120°C or lower. If the reaction temperature is high, the amount of so-called difficultly hydrolyzable chlorine increases, making it difficult to achieve high purification. The temperature is preferably 100°C or lower, and more preferably 85°C or lower.

[0057] Examples of epoxy resins used as raw materials include bisphenol type epoxy resins such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol acetophenone type epoxy resins, and diphenyl ether type epoxy resins, biphenol type epoxy resins, diphenyldicyclopentadiene type epoxy resins, alkylene glycol type epoxy resins, aliphatic cyclic epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, alkyl novolac type epoxy resins, styrenated phenol novolac type epoxy resins, naphthol novolac type epoxy resins, β-naphthalene novolac type epoxy resins, and the like. Examples of epoxy resins include novolac epoxy resins such as phthalocyanine aralkyl epoxy resins, dinaphthol aralkyl epoxy resins, and α-naphthol aralkyl epoxy resins, polyglycidyl ether compounds such as alicyclic epoxy resins, polyglycidyl amine compounds such as diaminodiphenylmethane epoxy resins, metaxylenediamine epoxy resins, 1,3-bisaminomethylcyclohexane epoxy resins, isocyanurate epoxy resins, and aminophenol epoxy resins, polyglycidyl ester compounds such as dimer acid epoxy resins and hexahydrophthalic acid epoxy resins, and alicyclic epoxy compounds. Other examples include, but are not limited to, trihydroxyphenylmethane epoxy resins. These epoxy resins may be used alone or in combination of two or more.

[0058] The reaction of the aromatic ester compound represented by general formula (1) and / or the carbonate ester compound represented by general formula (3) with the epoxy resin can be carried out by known methods. The active ester or active hydrogen of the aromatic ester compound represented by general formula (1) reacts with the epoxy group of the epoxy resin. One molecule of the carbonate ester compound represented by general formula (3) reacts with two epoxy groups of the epoxy resin, resulting in polycondensation. The end point of the reaction is confirmed by tracking the epoxy equivalent, when it reaches a value of 99% or more of the theoretical epoxy equivalent. Either method may be used, but it is necessary to sufficiently react the epoxy resin with the aromatic ester compound represented by general formula (1) and / or the carbonate ester compound represented by general formula (3). A catalyst is used in consideration of the reaction rate.

[0059] The amount of epoxy resin and aromatic ester compound represented by general formula (1) used is preferably 0.1 to 0.6 equivalents of ester group and / or hydroxyl group per equivalent of epoxy group, more preferably 0.3 to 0.6. This equivalent ratio facilitates the promotion of high molecular weight polymerization with epoxy groups at the molecular terminals. It is also possible to replace a portion of the aromatic ester compound with a bifunctional phenol compound. This allows the presence of an appropriate amount of secondary hydroxyl groups in the modified epoxy resin of the present invention through a reaction between the epoxy groups and hydroxyl groups of the epoxy resin, thereby enabling fine adjustment of solvent solubility, dielectric properties, moisture resistance, adhesiveness, and the like. On the other hand, the amount of the epoxy resin and the carbonate ester compound represented by general formula (3) used is preferably 0.1 to 0.6 equivalents per equivalent of epoxy group, more preferably 0.3 to 0.6. This equivalent ratio facilitates the promotion of high molecular weight polymerization with epoxy groups at the molecular terminals. It is also possible to replace a portion of the aromatic ester compound with a bifunctional phenol compound. This allows the presence of an appropriate amount of secondary hydroxyl groups in the modified epoxy resin of the present invention through a reaction between the epoxy groups and hydroxyl groups of the epoxy resin, thereby enabling fine adjustment of solvent solubility, dielectric properties, moisture resistance, adhesiveness, and the like.

[0060] The reason why the effects of the present invention are achieved is believed to be that the carboxylic acid salt of a quaternary phosphonium salt used as a catalyst is a compound with catalytic activity that causes the aromatic ester compound represented by general formula (1) and / or the carbonate ester compound represented by the following general formula (3) to react preferentially with the epoxy group rather than the secondary hydroxyl group of the epoxy resin, and the reduction in impurity components lowers the dispersity (Mw / Mn), resulting in improved mechanical strength and adhesiveness. Furthermore, the carboxylic acid salt of a quaternary phosphonium salt used as a catalyst may be used alone or in combination of two or more.

[0061] It is particularly preferable that the carboxylic acid salt of the quaternary phosphonium salt contains a salt of a phosphonium cation represented by the following general formula (7) and an anionic residue of a carboxylic acid. [ka]

[0062] Here, in equation (7), R 8 , R 9 , R 10 and R 11 are independently a group selected from an alkyl group having 1 to 12 carbon atoms or a phenyl group which may have a substituent on the aromatic ring.

[0063] The alkyl group having 1 to 12 carbon atoms may be linear, branched, or cyclic, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a t-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, a t-pentyl group, a cyclopentyl group, an n-hexyl group, an isohexyl group, a cyclohexyl group, an n-heptyl group, a cycloheptyl group, a methylcyclohexyl group, an n-octyl group, a cyclooctyl group, an n-nonyl group, a 3,3,5-trimethylcyclohexyl group, an n-decyl group, a cyclodecyl group, an n-undecyl group, an n-dodecyl group, a cyclododecyl group, a benzyl group, a methylbenzyl group, a dimethylbenzyl group, a trimethylbenzyl group, a naphthylmethyl group, a phenethyl group, and a 2-phenylisopropyl group.

[0064] Examples of the phenyl group which may have a substituent on the aromatic ring include a phenyl group and a p-tolyl group.

[0065] The anion residue of the carboxylic acid is not limited as long as it forms a salt with the phosphonium cation represented by the formula (7), but in terms of producing the catalytic effect in the above-mentioned reaction, it is preferable that it is derived from a carboxylic acid having two or more polybasic acid structures. Here, the anion residue of the carboxylic acid refers to a monovalent or divalent or higher carboxy anion formed by removing a hydrogen atom from one or more carboxy groups of the carboxylic acid.

[0066] The carboxylic acid that provides such an anionic residue of a carboxylic acid is not limited, and examples thereof include aliphatic carboxylic acids, alicyclic carboxylic acids, aromatic carboxylic acids, and anhydrides thereof. Examples of aliphatic carboxylic acids include mono- to tetracarboxylic acids, which may contain a hydroxyl group or an unsaturated bond. Examples include monocarboxylic acids such as acetic acid, lactic acid, hexanoic acid, octanoic acid, and decanoic acid, dicarboxylic acids such as succinic acid, malic acid, adipic acid, and maleic acid, tricarboxylic acids such as citric acid and aconitic acid, and tetracarboxylic acids such as 1,2,3,4-butanetetracarboxylic acid.

[0067] Examples of the alicyclic carboxylic acid include monovalent alicyclic carboxylic acids such as cyclohexanecarboxylic acid, divalent alicyclic carboxylic acids such as 1,2-cyclohexanedicarboxylic acid, trivalent alicyclic carboxylic acids such as cyclohexane-1,3,5-tricarboxylic acid, and tetravalent alicyclic carboxylic acids such as 1,2,4,5-cyclohexanetetracarboxylic acid.

[0068] Further, examples of aromatic carboxylic acids include monovalent aromatic carboxylic acids such as benzoic acid and salicylic acid, divalent aromatic carboxylic acids such as phthalic acid, methylphthalic acid, hydroxyphthalic acid and 2,3-naphthalenedicarboxylic acid, trivalent aromatic carboxylic acids such as 1,3,5-benzenetricarboxylic acid, and tetravalent aromatic carboxylic acids such as pyromellitic acid.

[0069] The salt of the phosphonium cation represented by the formula (7) and the anionic residue of a carboxylic acid is preferably a 1:1 salt of 1 mole of the phosphonium cation and 1 mole of at least one kind of the anionic residue of the carboxylic acid. A preferred embodiment of the carboxylic acid salt of a quaternary phosphonium salt in the present invention is tetrabutylphosphonium hydrogenhexahydrophthalate, which is a salt of a tetrabutylphosphonium cation and a monovalent anion of 1,2-cyclohexanedicarboxylic acid, as represented by the following formula (8), but is not limited thereto. [ka]

[0070] In the present invention, it is essential to use the carboxylic acid salt of the quaternary phosphonium salt as the catalyst. However, other known catalysts may also be used, and the use of such catalysts is not excluded as long as they have the catalytic ability to promote the reaction between the epoxy group and the ester group. In this case, the carboxylic acid salt of the quaternary phosphonium salt is preferably used in an amount of 50% by mass or more, more preferably 75% by mass or more, and even more preferably 90% by mass or more, of the catalyst used. Examples of other catalysts include known tertiary amines, cyclic amines, imidazole compounds, organic phosphorus compounds, and quaternary ammonium salts. These other catalysts may be used alone or in combination of two or more.

[0071] The amount of catalyst used is usually 0.001 to 1 mass% of the reaction solids, but when these compounds are used as catalysts, the catalyst remains as residue in the resulting modified epoxy resin, which may deteriorate the insulating properties of the printed wiring board or shorten the pot life of the composition, so the content of catalyst-derived nitrogen in the modified epoxy resin is preferably 0.5 mass% or less, more preferably 0.3 mass% or less. Also, the content of catalyst-derived phosphorus in the modified epoxy resin is preferably 0.5 mass% or less, more preferably 0.3 mass% or less.

[0072] In the production method of the present invention, a reaction solvent may be used, and any solvent that can dissolve the modified epoxy resin may be used. Examples of the solvent include aromatic solvents, ketone solvents, amide solvents, glycol ether solvents, and ester solvents. These solvents may be used alone or in combination of two or more.

[0073] In the production method, the solids concentration during the reaction is preferably 35 to 100% by mass, more preferably 50 to 90% by mass, and even more preferably 70 to 90% by mass. If a highly viscous product is produced during the reaction, the reaction can be continued by adding additional solvent. After the reaction is complete, the solvent can be removed or further added as necessary.

[0074] The reaction temperature is set within a range that does not decompose the catalyst used. If the reaction temperature is too high, the catalyst may decompose, halting the reaction or degrading the resulting modified epoxy resin. If the reaction temperature is too low, the reaction may not proceed sufficiently to achieve the desired molecular weight. Therefore, the reaction temperature is preferably 50 to 230°C, more preferably 70 to 210°C, even more preferably 90 to 200°C, and particularly preferably 100 to 180°C. The reaction time is typically 1 to 12 hours, preferably 3 to 10 hours. When using a low-boiling solvent such as acetone or methyl ethyl ketone, the reaction temperature can be maintained by conducting the reaction under high pressure using an autoclave. If the heat of reaction needs to be removed, this is usually achieved by evaporating, condensing, and refluxing the solvent using the heat of reaction, indirect cooling, or a combination of these.

[0075] The modified epoxy resin obtained by the method of the present invention can be suitably used as an epoxy resin composition (sometimes simply referred to as a "resin composition") using the same. The epoxy resin composition is a resin composition containing at least the modified epoxy resin obtained by the method of the present invention and a curing agent. Furthermore, the epoxy resin composition can be appropriately blended with various additives such as other epoxy resins described below, inorganic fillers, coupling agents, and antioxidants, as needed. The epoxy resin composition gives a cured product that fully satisfies the various physical properties required for various applications.

[0076] Here, the curing agent refers to a substance that contributes to the crosslinking reaction with the epoxy resin. In the present invention, even substances that are usually called curing accelerators are considered to be curing agents as long as they contribute to the crosslinking reaction of the epoxy resin.

[0077] The content of the curing agent in the resin composition is preferably 0.1 to 150 parts by mass, more preferably 2 to 130 parts by mass, per 100 parts by mass of the modified epoxy resin (or all epoxy resins including other epoxy resins if other epoxy resins are contained). Note that this refers to the amount of nonvolatile content (solid content) in the resin composition.

[0078] When the resin composition contains other epoxy resins, the modified epoxy resin obtained by the method of the present invention preferably accounts for 1 to 99 mass % of the total epoxy resins, more preferably 50 mass % or more, and even more preferably 80 mass % or more. In the present invention, the term "solid content" refers to the components excluding the solvent, and includes not only solid modified epoxy resins and other epoxy resins, but also semi-solid and viscous liquids. The term "resin component" refers to the total of the modified epoxy resin obtained by the method of the present invention and other epoxy resins.

[0079] The curing agent used in the resin composition is not particularly limited, and any curing agent generally known as an epoxy resin curing agent can be used. From the viewpoint of improving heat resistance, preferred curing agents include phenolic resins, amide compounds, imidazole compounds, and active ester curing agents. These curing agents may be used alone or in combination of two or more.

[0080] Examples of other curing agents include acrylic ester resins, melamine resins, urea resins, cationic polymerization agents, amine compounds, acid anhydrides, tertiary amines, organic phosphines, phosphonium salts, tetraphenylboron salts, organic acid dihydrazides, boron halide amine complexes, polymercaptan curing agents, isocyanate compounds, polyisocyanate compounds, blocked isocyanate compounds, carbodiimide compounds, etc. These other curing agents may be used alone, or two or more may be mixed in any combination and ratio.

[0081] The resin composition may contain other epoxy resins in addition to the modified epoxy resin obtained by the method of the present invention. The use of other epoxy resins can compensate for insufficient physical properties or improve various physical properties. The epoxy resin preferably has two or more epoxy groups in the molecule, and more preferably has three or more epoxy groups. Examples include polyglycidyl ether compounds, polyglycidyl amine compounds, polyglycidyl ester compounds, alicyclic epoxy compounds, and other modified epoxy resins. These epoxy resins may be used alone, or two or more types of epoxy resins of the same type may be used in combination, or different types of epoxy resins may be used in combination.

[0082] A solvent or reactive diluent may be blended into the resin composition to appropriately adjust the viscosity of the resin composition when handling it to form a coating film. In the resin composition, the solvent or reactive diluent is used to ensure the handleability and workability of the resin composition when molding it, and there is no particular limit to the amount used. In the present invention, the term "solvent" and the aforementioned term "solvent" are used to distinguish between them depending on their use form, but they may be the same or different independently.

[0083] Examples of solvents that the resin composition may contain include ketones such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone, and cyclohexanone, esters such as ethyl acetate, ethers such as ethylene glycol monomethyl ether, amides such as N,N-dimethylformamide and N,N-dimethylacetamide, alcohols such as methanol and ethanol, alkanes such as hexane and cyclohexane, aromatics such as toluene and xylene, etc. The above-mentioned solvents may be used alone, or two or more may be mixed in any combination and ratio.

[0084] Examples of reactive diluents include monofunctional glycidyl ethers such as allyl glycidyl ether, bifunctional glycidyl ethers such as propylene glycol diglycidyl ether, polyfunctional glycidyl ethers such as trimethylolpropane polyglycidyl ether, glycidyl esters, and glycidyl amines.

[0085] These solvents or reactive diluents are preferably used in an amount of 90% by mass or less, particularly 20 to 80% by mass, based on nonvolatile content, with the appropriate type and amount being selected appropriately depending on the application. For example, for printed wiring 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, with the amount used being 40 to 80% by mass based on nonvolatile content. For adhesive film applications, for example, ketones, acetate esters, carbitols, aromatic hydrocarbons, dimethylformamide, dimethylacetamide, and N-methylpyrrolidone are preferred, with the amount used being 30 to 60% by mass based on nonvolatile content.

[0086] If necessary, a curing accelerator or catalyst can be used in the resin composition. Examples of the curing accelerator or catalyst include imidazole compounds, tertiary amines, phosphorus compounds such as phosphines, metal compounds, Lewis acids, and amine complex salts. These may be used alone or in combination of two or more.

[0087] The amount of curing accelerator or catalyst may be appropriately selected depending on the intended use, but 0.01 to 15 parts by mass is used as needed per 100 parts by mass of the epoxy resin components in the resin composition (all epoxy resins including the modified epoxy resin obtained by the method of the present invention). The amount is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 8 parts by mass, even more preferably 0.1 to 5 parts by mass, and particularly preferably 0.1 to 1.0 part by mass. The use of a curing accelerator or catalyst can lower the curing temperature and shorten the curing time.

[0088] Various known flame retardants can be used in the resin composition to improve the flame retardancy of the resulting cured product, as long as the reliability is not reduced. Usable flame retardants include, for example, halogen-based flame retardants, phosphorus-based flame retardants, nitrogen-based flame retardants, silicone-based flame retardants, inorganic flame retardants, and organic metal salt-based flame retardants. From an environmental perspective, halogen-free flame retardants are preferred, and phosphorus-based flame retardants are particularly preferred. These flame retardants may be used alone, or two or more of the same type of flame retardants may be used in combination, or different types of flame retardants may be used in combination.

[0089] The resin composition may contain components other than those described above to further improve its functionality, such as fillers, thermoplastic resins, thermosetting resins, photocurable resins, ultraviolet inhibitors, antioxidants, coupling agents, plasticizers, fluxes, thixotropic agents, smoothing agents, colorants, pigments, dispersants, emulsifiers, elasticity reducing agents, release agents, antifoaming agents, and ion trapping agents.

[0090] The resin composition can be obtained by uniformly mixing the above components. The resin composition, which contains the modified epoxy resin, the curing agent, and, if necessary, various other components, can be easily cured by a method similar to that known in the art. This cured product exhibits low moisture absorption, excellent dielectric properties, and good cured physical properties. Curing here refers to intentionally curing the resin composition with heat and / or light, etc., and the degree of curing can be controlled depending on the desired physical properties and application. The degree of progress may be fully cured or semi-cured, and is not particularly limited, but the reaction rate of the curing reaction between the epoxy group and the curing agent is usually 5 to 95%.

[0091] The resin composition can be cured to obtain a cured product by the same method as for known epoxy resin compositions. Methods for obtaining a cured product include those similar to those for known epoxy resin compositions, such as casting, injection, potting, dipping, drip coating, transfer molding, and compression molding, as well as laminating resin sheets, resin-coated copper foils, prepregs, etc., and curing them under heat and pressure to form laminates. The curing temperature is typically in the range of 80 to 300°C, and the curing time is typically about 10 to 360 minutes. This heating is preferably carried out in two stages: a primary heating step at 80 to 180°C for 10 to 90 minutes, followed by a secondary heating step at 120 to 200°C for 60 to 150 minutes. Furthermore, for formulations whose glass transition temperature (Tg) exceeds the secondary heating temperature, a tertiary heating step at 150 to 280°C for 60 to 120 minutes is preferably carried out. Such secondary and tertiary heating steps can reduce poor curing. When producing a semi-cured resin product such as a resin sheet, a resin-coated copper foil, or a prepreg, the curing reaction of the resin composition is usually allowed to proceed to an extent that the shape can be maintained by heating, etc. When the resin composition contains a solvent, most of the solvent is usually removed by techniques such as heating, decompression, or air drying, but 5% by mass or less of the solvent may remain in the semi-cured resin product.

[0092] A prepreg obtained using the resin composition will now be described. The prepreg comprises the resin composition or a semi-cured product thereof and a fibrous substrate. The fibrous substrate can be, but is not limited to, woven or nonwoven fabrics made of inorganic fibers such as glass or organic fibers such as polyester, polyamine, polyacrylic, polyimide, Kevlar, or cellulose. The method for producing a prepreg from the resin composition and fibrous substrate is not particularly limited. For example, the substrate can be immersed in a resin varnish obtained by adjusting the viscosity of the resin composition with a solvent, and then heated and dried to semi-cure (B-stage) the resin component. For example, the prepreg can be obtained by heating and drying at 100 to 200°C for 1 to 40 minutes. The resin content in the prepreg is preferably 30 to 80% by mass.

[0093] A resin sheet obtained using a resin composition will now be described. The resin sheet comprises the resin composition or a semi-cured product thereof and a support film. Examples of the support film include, but are not limited to, polyolefins such as polyethylene, polypropylene, and polyvinyl chloride; polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate; polycarbonate; polyimide; and even release paper and metal foils such as copper foil and aluminum foil. The thickness of the support film is not particularly limited, but is typically 10 to 150 μm, preferably 25 to 50 μm. The method for producing a resin sheet from the resin composition and support film is not particularly limited, and examples include a method in which the resin composition is applied to the support film with a resin varnish whose viscosity has been adjusted with an aromatic or ketone solvent, followed by drying. The resin sheet is obtained by semi-curing (B-staging) the resin component by heating and drying, and can be obtained by, for example, heating and drying at 100 to 200°C for 1 to 40 minutes. The resin content in the resin sheet is preferably 30 to 80% by mass. The thickness of the resin component is not particularly limited, but is preferably in the range of 3 to 200 μm, more preferably 5 to 105 μm. The coating can be repeated multiple times as needed, and in this case, it is also possible to repeat the coating using multiple solutions with different compositions and concentrations, and adjust the final resin composition and resin amount to the desired one.

[0094] A method for manufacturing a laminate using prepreg or a resin sheet will be described. When forming a laminate using prepreg, for example, one or more prepreg sheets are laminated, and metal foil is placed on one or both sides to form a laminate, which is then heated and pressed to be integrated. Here, the metal foil can be a single, alloy, or composite metal foil of copper, aluminum, brass, nickel, or the like. The conditions for heating and pressing the laminate can be appropriately adjusted to the conditions under which the resin composition hardens. If the pressure is too low, air bubbles may remain inside the resulting laminate, potentially reducing its electrical properties. Therefore, it is desirable to pressurize under conditions that satisfy moldability. For example, a temperature of 160 to 220°C and a pressure of 49 to 490 N / cm are used. 2(5-50kgf / cm 2 ) and the heating time can be set to 10 to 240 minutes. A resin sheet can also be used instead of the prepreg.

[0095] Furthermore, a multilayer board can be produced using the single-layer laminate obtained in this way as an inner layer material. In this case, a circuit is first formed on the laminate by an additive method, a subtractive method, or the like, and the surface of the formed circuit is blackened by treating it with an acid solution to obtain an inner layer material. An insulating layer is formed on one or both circuit-forming surfaces of this inner layer material using a prepreg or a resin sheet, and a conductor layer is formed on the surface of the insulating layer to form a multilayer board.

[0096] When forming an insulating layer using a resin sheet, a laminate is formed by placing a resin sheet on the circuit-forming surfaces of multiple inner layer materials. Alternatively, a resin sheet is placed between the circuit-forming surfaces of the inner layer materials and a metal foil to form a laminate. This laminate is then heated and pressurized to form an integral molding, thereby forming the cured resin sheet as an insulating layer and forming a multilayer inner layer material. Alternatively, the inner layer material and the metal foil as a conductor layer are combined to form the cured resin sheet as an insulating layer. Here, the metal foil can be the same as that used in the laminate used as the inner layer material. Furthermore, the hot and pressure molding can be carried out under the same conditions as those for molding the inner layer material. When forming an insulating layer by applying a resin composition to a laminate, the resin for forming the circuit on the outermost layer of the inner layer material is preferably applied to a thickness of 5 to 100 μm with the above-mentioned resin composition, and then heated and dried at 100 to 200°C for 1 to 90 minutes to form a sheet. This is generally formed by a method called a casting method. The thickness after drying is preferably formed to 5 to 80 μm. A printed wiring board can be formed by further forming via holes and circuits on the surface of the multilayer laminate thus formed by an additive method or a subtractive method. Furthermore, by repeating the above process using this printed wiring board as an inner layer material, it is possible to form a multi-layer laminate.

[0097] When forming an insulating layer using prepreg, one or more prepreg sheets are placed on the circuit-forming surface of the inner layer material, and a metal foil is placed on the outside of the prepreg to form a laminate. This laminate is then heated and pressurized to form an integral molding, whereby the cured prepreg is formed as an insulating layer and the outer metal foil is formed as a conductor layer. Here, the metal foil may be the same as that used in the laminate used as the inner layer material. The hot-press molding can be carried out under the same conditions as those for molding the inner layer material. The surface of the multilayer laminate thus molded can be further subjected to via hole formation and circuit formation by an additive method or a subtractive method to mold a printed wiring board. Furthermore, by repeating the above process using this printed wiring board as an inner layer material, it is possible to form a multi-layer board with even more layers.

[0098] Furthermore, when a resin sheet is used as a bonding sheet, for example, two substrates can be bonded together with the resin sheet. Each of the two substrates is, for example, a laminate or a printed wiring board. Specifically, for example, a resin sheet is produced by forming an epoxy resin composition into a sheet on a support film by a coating method or the like, and then heating it to dry or semi-cure it. This resin sheet is then placed on a substrate (first substrate), the support film is peeled off from the resin sheet, and another substrate (second substrate) is placed on top of it. That is, the first substrate, the resin sheet (epoxy resin composition), and the second substrate are laminated in this order. Subsequently, the first substrate and the second substrate are bonded together via the cured product of the epoxy resin composition by heating and curing.

[0099] Cured products and laminates for electrical and electronic circuits obtained from epoxy resin compositions using modified epoxy resins obtained by the method of the present invention have excellent low dielectric properties, adhesive properties, and mechanical strength. [Example]

[0100] The present invention will be explained in more detail below with reference to examples and comparative examples, but is not limited to these. Unless otherwise specified, "parts" means parts by mass, and "%" means % by mass. Analytical and measurement methods are also shown below. The unit of equivalent weight is "g / eq."

[0101] (1) Epoxy equivalent: The measurement was carried out in accordance with JIS K 7236. Specifically, a potentiometric titrator was used, chloroform was used as the solvent, tetraethylammonium bromide acetate solution was added, and a 0.1 mol / L perchloric acid-acetic acid solution was used.

[0102] (2) Weight average molecular weight (Mw), number average molecular weight (Mn), dispersity (Mw / Mn): The chromatographic index was determined by GPC measurement. Specifically, a Tosoh HLC8320 GPC main unit equipped with columns (TSKgel SuperH-H, SuperH2000, SuperHM-H, and SuperHM-H, all manufactured by Tosoh) was used. The column temperature was 40°C. Tetrahydrofuran (THF) was used as the eluent at a flow rate of 1.0 mL / min, and a refractive index detector was used. 0.1 g of solids was dissolved in 10 mL of THF and filtered through a 0.45 μm microfilter. 50 μL of the sample was used. A calibration curve was prepared using standard polystyrenes (Tosoh PStQuick A, PStQuick B, and PStQuick C). Data processing was performed using a Tosoh GPC8020 Model II version 6.00.

[0103] (3) Dielectric constant and dielectric loss tangent: The measurement equipment used was a Keysight Technologies network analyzer (E8363C) as the network analyzer and split post dielectric resonators (SPDR) as the resonators, and measurements were carried out in an environment of 23°C and 50% humidity.

[0104] (4) Copper foil peel strength: Measurements were made in accordance with JIS C6481 standard.

[0105] (5) Tensile modulus, tensile strength, tensile elongation: The test was conducted in accordance with JIS K7161. Specifically, a universal material testing machine (Autograph AGS-H manufactured by Shimadzu Science Co., Ltd.) was used. At room temperature, a dumbbell test piece measuring 215 mm in total length including the grip, 10 mm in width, and 2 mm in thickness was subjected to a tensile test with a chuck distance of 114 mm and a speed of 50 mm / min. The tensile strength, tensile modulus, and tensile elongation were determined from the obtained stress-strain diagram.

[0106] The abbreviations used in the examples and comparative examples are as follows: [Epoxy resin] A1: Bisphenol f type liquid epoxy resin (Nippon Steel Chemical & Material Co., Ltd., YDf-170, epoxy equivalent weight 168) A2: Tetramethylbisphenol f-type epoxy resin (Nippon Steel Chemical & Material Co., Ltd., YSLV-80XY, epoxy equivalent weight 192) A3: Bisphenol A liquid epoxy resin (Nippon Steel Chemical & Material Co., Ltd., Y D-128, epoxy equivalent 186)

[0107] [Phenol compounds] B1: 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (manufactured by Sanko Co., Ltd., HCA-HQ, hydroxyl equivalent 162) [ka]

[0108] [Aromatic ester compounds] C1: 10-(2,5-diacetoxyphenyl)-9,10-dihydro9-oxa-10-phosphaphenanthrene-10-oxide (compound obtained in Synthesis Example 1, active equivalent: 204. Here, active equivalent refers to the equivalent of the active ester group). [ka] C2: 4,4'-diacetoxybiphenyl (Tokyo Chemical Industry Co., Ltd., active equivalent weight 135) [ka]

[0109] [Carbonate ester compounds] D1: Diphenyl carbonate (Tokyo Chemical Industry Co., Ltd., active equivalent weight 107) [ka]

[0110] [catalyst] E1: Pyridine (Fujifilm Wako Pure Chemical Industries, Ltd.) E2: Tetrabutylphosphonium hydrogen hexahydrophthalate (Hokko Chemical Industry Co., Ltd., TBP-3S) [ka] E3: 4-Dimethylaminopyridine (Fujifilm Wako Pure Chemical Industries, Ltd.) [ka] E4: 2-ethyl-4-methylimidazole (Curesol 2E4MZ, manufactured by Shikoku Chemicals Corporation)

[0111] [Hardening agent] F1: Phenolic resin (Aica Kogyo Co., Ltd., Shounol BRG-557, phenolic hydroxyl group equivalent: 105)

[0112] [Acid anhydride] G1: Acetic anhydride (Fujifilm Wako Pure Chemical Industries, Ltd.)

[0113] Synthesis Example 1 A four-necked glass separable flask equipped with a stirrer, thermometer, condenser, and nitrogen gas inlet was charged with 100 parts of phenol compound (B1) and 252 parts of acid anhydride (G1) at room temperature, and the mixture was heated to 70°C while stirring under nitrogen gas flow. 0.98 parts of catalyst (E1) was added, and the reaction was carried out for 5 hours. The mixture was then dried under reduced pressure at 180°C and 1.3 kPa (10 torr) for 3 hours to obtain 120 parts of aromatic ester compound (C1).

[0114] Example 1 A four-necked glass separable flask equipped with a stirrer, a thermometer, a condenser, and a nitrogen gas inlet was charged with 100 parts of bisphenol f-type liquid epoxy resin (A1) as an epoxy resin and 65 parts of 10-(2,5-diacetoxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (C1) as an aromatic ester compound at room temperature, and the mixture was heated to 125°C while stirring and nitrogen gas was passed through. 0.08 parts of catalyst (E2) was then added, and the mixture was heated to 150°C and reacted at the same temperature for 5 hours to obtain a modified epoxy resin (R1).

[0115] Examples 2 to 3, Comparative Examples 1 to 3 The same procedure as in Example 1 was carried out using the amounts (parts) of each raw material shown in Tables 1 and 2 to obtain modified epoxy resins (R2 to R3) according to Examples 2 and 3, and reaction products (HR1 to HR3) according to Comparative Examples 1 to 3. The epoxy equivalent, weight-average molecular weight (Mw), number-average molecular weight (Mn), and dispersity (Mw / Mn) of the obtained modified epoxy resins (R1 to R3) and reaction products (HR1 to HR3) were measured. The results are shown in Table 1. Figure 1 shows GPC charts of the modified epoxy resins (R1 and HR1) obtained in Example 1 and Comparative Example 1. In Figure 1, the solid line indicates the GPC chart of R1, and the dashed line indicates the GPC chart of HR1.

[0116] [Table 1]

[0117] Example 4 100 parts of the modified epoxy resin (R1) obtained in Example 1 and 17 parts of the curing agent (F1) were mixed and dissolved in a mixed solvent prepared from MEK and propylene glycol monomethyl ether to obtain a resin composition varnish.

[0118] The obtained resin composition varnish was impregnated into a glass cloth (WEA 7628 XS13, 0.18 mm thick, manufactured by Nitto Boseki Co., Ltd.) The impregnated glass cloth was dried in a hot air circulating oven at 150°C for 5 minutes to obtain a prepreg.

[0119] Eight sheets of the resulting prepreg were layered on top and bottom with copper foil (3EC-III, 35 μm thick, manufactured by Mitsui Mining & Smelting Co., Ltd.), and vacuum pressed at 2 MPa under the temperature conditions of 130°C for 15 minutes and 170°C for 80 minutes to obtain a laminate. The copper foil peel strength of the laminate was measured, and the results are shown in Table 2.

[0120] The obtained prepreg was then loosened and sieved to form a powdered prepreg, passing through a 100-mesh sieve. The obtained prepreg powder was placed in a fluororesin mold and vacuum pressed at 2 MPa under the following temperature conditions: 130°C for 15 minutes and 190°C for 80 minutes to obtain a test specimen. The evaluation results for the dielectric constant and dielectric loss tangent of the test specimen are shown in Table 2.

[0121] The resulting prepreg was then loosened and sieved to a powder form, passing through a 100-mesh sieve. The resulting prepreg powder was placed in a fluororesin mold hollowed out to the shape specified in JIS K-7161, and subjected to a vacuum press at 2 MPa under the following temperature conditions: 130°C for 15 minutes and 190°C for 80 minutes, yielding test specimens for tensile testing. The evaluation results for the tensile modulus, tensile strength, and tensile elongation of the test specimens are shown in Table 2.

[0122] Examples 5 to 6, Comparative Examples 4 to 6 The components were compounded in the amounts (parts) shown in Table 2, and the same operations as in Example 4 were carried out to obtain a resin composition varnish, a prepreg, a laminate, and a test piece. Tests similar to those in Example 4 were carried out, and the results are shown in Table 2. Here, the copper foil peel strength and tensile strength were compared with the results when resins of the same type were used as the epoxy resins A1 to A3, and the results were also shown as ratios (Example 4 / Comparative Example 4, Example 5 / Comparative Example 5, Example 6 / Comparative Example 6).

[0123] [Table 2]

[0124] As can be seen from Table 2, the cured products obtained using the modified epoxy resins obtained by the method of the present invention have excellent adhesiveness and mechanical strength while maintaining low dielectric constants and dielectric loss tangents.

Claims

1. A method for producing a modified epoxy resin by reacting an aromatic ester compound represented by the following general formula (1) and / or a carbonate ester compound represented by the following general formula (3) with an epoxy resin in the presence of a catalyst, comprising:

1. A method for producing a modified epoxy resin, wherein the catalyst is a carboxylic acid salt of a quaternary phosphonium salt. 【Chemistry 1】 In formula (1), A is an aromatic ring selected from the group consisting of a benzene ring, a naphthalene ring, a biphenyl ring, and a bisphenyl ring, and these aromatic rings may have a substituent, and may have an oxygen atom, a phosphorus atom, a nitrogen atom, and / or a sulfur atom. １ and X ２ are acyloxy groups or hydroxyl groups represented by the following formula (2), and at least one of them is an acyloxy group. 【Chemistry 2】 In formula (2), R １ is a methyl group or a phenyl group. * indicates the bonding position. 【Transformation 3】 In formula (3), R ２ and R ３ are independently a group selected from an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, and an alkynyl group having 2 to 12 carbon atoms.

2. 2. The method for producing a modified epoxy resin according to claim 1, wherein the aromatic ester compound is a phosphorus compound represented by the following general formula (4) and / or general formula (5): 【Chemistry 4】 In formula (4) and formula (5), B is a benzene ring or a naphthalene ring, which may have a hydrocarbon group having 1 to 12 carbon atoms as a substituent, and the substituent may have a hetero element. ４ and R ５ is a hydrocarbon group having 1 to 12 carbon atoms which may have a heteroatom, and together with the phosphorus atom, R ４ , R ５ may be bonded to form a cyclic structure. n is 0 or 1. X １ and X ２ has the same meaning as general formula (1).

3. 2. The method for producing a modified epoxy resin according to claim 1, wherein the carbonate ester is diphenyl carbonate represented by the following general formula (6): 【Transformation 5】

4. 2. The method for producing a modified epoxy resin according to claim 1, wherein the carboxylic acid salt of the quaternary phosphonium salt comprises a salt of a phosphonium cation represented by the following general formula (7) and an anionic residue of a carboxylic acid: 【Transformation 6】 In formula (7), R ８ , R ９ , R １０ and R １１ are independently a group selected from alkyl groups having 1 to 12 carbon atoms and phenyl groups which may have a substituent on the aromatic ring.

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