Epoxy resin composition, reinforcing fiber-containing epoxy resin composition, prepreg, and fiber-reinforced plastic using these

Abstract

To provide: an epoxy resin composition with an excellent compatibility suitable for an on-site polymerization type fiber-reinforced thermoplastic application; a reinforcing fiber-containing epoxy resin composition containing the epoxy resin composition; a prepreg; and a fiber-reinforced plastic excellent in strength, elastic modulus and heat resistance by using these.SOLUTION: There is provided an epoxy resin composition containing a bifunctional epoxy resin, a compound represented by the following general formula (1), and a polymerization catalyst, wherein the amount of the compound represented by the general formula (1) is 0.90 to 1.10 mol based on 1 mol of the bifunctional epoxy resin. (In the formula (1), X is a divalent group. Q is a 5-20C unsaturated heterocyclic ring-containing acyl group or a hydrogen atom, and 5 mol% or more is the above acyl group. Further, the compound represented by the general formula (1) may be a mixture of two or more selected from a compound in which both of Q's are the acyl groups, a compound in which one of Q's is the acyl group, and a compound in which both of Q's are hydrogen atoms.)SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an epoxy resin composition, a reinforcing fiber-containing epoxy resin composition, a prepreg, and a fiber-reinforced plastic using the same. [Background technology]

[0002] Fiber-reinforced plastics (FRP) have excellent physical properties such as light weight and high strength, and are used in many fields. Among them, those using carbon fiber as the reinforcing fiber (CFRP) are known to have particularly excellent mechanical strength.

[0003] Epoxy resin is mainly used as the base resin for FRP because it has an excellent balance between price and physical properties. A method has been proposed in which epoxy compounds and / or phenolic hydroxyl group-containing compounds are mixed with reinforcing fibers in advance, polymerized by polyaddition reaction using a polymerization catalyst, and fiber-reinforced thermoplastic resin is molded. This epoxy resin is also called in-situ polymerization thermoplastic epoxy resin, and FRP using this is expected to have excellent mass production, moldability, and recyclability. In-situ polymerization thermoplastic epoxy resin has good impregnation properties because it is impregnated into fibers in a low viscosity state before polymerization, and the proportion of reinforcing fibers can be increased. It has superior impact strength and toughness compared to general-purpose thermosetting epoxy resins. In particular, Patent Document 1 reports that the heat resistance of FRP can be improved by using a compound having a fluorene skeleton in an epoxy compound and / or a phenolic hydroxyl group-containing compound.

[0004] However, since the epoxy compound having a fluorene skeleton and the compound containing a phenolic hydroxyl group described in Patent Document 1 are difficult to melt and it is difficult to obtain a homogeneous mixture of precursors to an epoxy resin composition, it has been found that the bending strength is insufficient, and the application to members used under high bending stress has been limited. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2006 / 123577 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide an epoxy resin composition having excellent compatibility, and a fiber-reinforced plastic using the epoxy resin composition, which has excellent strength, elastic modulus and heat resistance. [Means for solving the problem]

[0007] In order to solve the above problems, the present inventors have conducted extensive research into epoxy resin compositions and have found that an epoxy resin composition using a compound having a specific structure and represented by general formula (1) has excellent compatibility, and further found that a fiber-reinforced plastic using a prepreg made of a reinforcing fiber-containing epoxy resin composition containing the same has excellent heat resistance, strength and elastic modulus, thereby completing the present invention.

[0008] That is, the present invention relates to an epoxy resin composition comprising a bifunctional epoxy resin, a compound represented by general formula (1), and a polymerization catalyst, wherein the amount of the compound represented by general formula (1) is 0.90 to 1.10 mol per 1 mol of the bifunctional epoxy resin. [ka] Here, X is a divalent group. Q is an unsaturated heterocycle-containing acyl group having 5 to 20 carbon atoms or a hydrogen atom, and 5 mol % or more of the acyl group is the above. The compound represented by general formula (1) may be a mixture of two or more selected from a compound in which both Qs are the above acyl group, a compound in which one Q is the above acyl group, and a compound in which both Qs are hydrogen atoms.

[0009] The unsaturated heterocyclic ring-containing acyl group having 5 to 20 carbon atoms is preferably any one of the unsaturated heterocyclic ring-containing acyl groups represented by the following formulas (2a) to (2f). [ka] Here, R 1 ~R 6 are independently a hydrocarbon group having 1 to 6 carbon atoms, n1 is an integer of 0 to 3, n2 is an integer of 0 to 5, n3 is an integer of 0 to 5, n4 is an integer of 0 to 4, n5 is an integer of 0 to 6, and n6 is an integer of 0 to 8. W is an oxygen atom or a sulfur atom.

[0010] The content of the polymerization catalyst is preferably 0.001 to 10 parts by weight per 100 parts by weight of the total amount of the difunctional epoxy resin and the compound represented by general formula (1).

[0011] It is preferred that the epoxy resin composition of the present invention does not contain an organic solvent, or if it contains an organic solvent, the content of the organic solvent is from 0.01 to 10% by weight of the epoxy resin composition, the viscosity at 85°C is from 0.1 to 100 Pa s, and the bifunctional epoxy resin and the compound represented by general formula (1) are uniformly dissolved in the epoxy resin composition.

[0012] The present invention also relates to a reinforcing fiber-containing epoxy resin composition comprising the above-mentioned epoxy resin composition and reinforcing fibers, and the reinforcing fibers are preferably carbon fibers in an amount of 20 to 80% by weight.

[0013] The present invention also relates to a prepreg comprising the above-mentioned reinforcing fiber-containing epoxy resin composition.

[0014] The present invention also relates to a fiber-reinforced plastic using the above-mentioned reinforcing fiber-containing epoxy resin composition.

[0015] The present invention also relates to a fiber-reinforced plastic using the above prepreg. Effect of the Invention

[0016] The epoxy resin composition of the present invention has excellent compatibility and is therefore suitable for use in in-situ polymerization type fiber reinforced thermoplastics. The epoxy resin composition of the present invention can also provide fiber reinforced plastics (FRP) with excellent heat resistance, strength and elastic modulus. In particular, the introduction of furyl groups is beneficial in terms of carbon neutrality, since a raw material that can be obtained from a biomass raw material (corn) is used. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The present invention will be described in detail below based on preferred embodiments thereof. The epoxy resin composition of the present invention is a composition that contains a compound represented by general formula (1), a bifunctional epoxy resin, and a polymerization catalyst as essential components, and is polymerized by heating to become a thermoplastic. This composition may contain additives such as a bifunctional phenol compound, an organic solvent, a filler, or a flame retardant. The reinforcing fiber-containing epoxy resin composition of the present invention contains this epoxy resin composition and reinforcing fibers as essential components.

[0018] The bifunctional epoxy resin used in the epoxy resin composition may be an epoxy resin having two epoxy groups in the molecule. If the purity of the bifunctional epoxy resin is high, it may contain positional isomers or oligomers, and the purity of the bifunctional epoxy resin is preferably 95% by weight or more. These bifunctional epoxy resins may be used alone or in combination.

[0019] The difunctional epoxy resin is particularly preferably a difunctional epoxy resin represented by the following general formula (4). [ka] In the formula, Z 2 is a divalent group, and is preferably a divalent group represented by the following formula (4b). 1 is a glycidyl group. [ka]

[0020] In formula (4b), Z 1 is a divalent group represented by the following formula (4c). [ka]

[0021] In formula (4b), m is the number of repetitions, and its average value is from 0 to 6, and preferably from 0 to 3. In formula (4c), k is 0, 1 or 2, and preferably 0 or 1.

[0022] In formula (4c), Ar is independently an aromatic ring group of either a benzene ring or a naphthalene ring. These aromatic rings may have any of 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 aralkyl group having 7 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, an aralkyloxy group having 7 to 13 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, or an alkynyl group having 2 to 12 carbon atoms as a substituent.

[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, and a cyclododecyl group.

[0024] The alkoxy group having 1 to 12 carbon atoms may be linear, branched, or cyclic, and examples thereof 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, a methylcyclohexyloxy group, an n-octyloxy group, a cyclooctyloxy group, an n-nonyloxy group, a 3,3,5-trimethylcyclohexyloxy group, an n-decyloxy group, a cyclodecyloxy group, an n-undecyloxy group, an n-dodecyloxy group, and a cyclododecyloxy group.

[0025] Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, an o-tolyl group, a 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 vinylnaphthyl group.

[0026] 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.

[0027] Examples of the aryloxy group having 6 to 12 carbon atoms include a phenoxy group, an o-tolyloxy group, a m-tolyloxy group, a p-tolyloxy group, an ethylphenoxy group, a styryloxy group, a xylyloxy group, an n-propylphenoxy group, an isopropylphenoxy group, a mesityloxy group, an ethynylphenoxy group, a naphthyloxy group, and a vinylnaphthyloxy group.

[0028] Examples of the aralkyloxy group having 7 to 13 carbon atoms include a benzyloxy group, a methylbenzyloxy group, a dimethylbenzyloxy group, a trimethylbenzyloxy group, a phenethyloxy group, a 1-phenylethoxy group, a 2-phenylisopropoxy group, and a naphthylmethoxy group.

[0029] Examples of alkenyl groups having 2 to 12 carbon atoms include vinyl groups, 1-propenyl groups, 2-propenyl groups, 1-methylvinyl groups, 1-butenyl groups, 2-butenyl groups, 3-butenyl groups, 1,3-butadienyl groups, cyclohexenyl groups, cyclohexadienyl groups, cinnamyl groups, and naphthylvinyl groups.

[0030] 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-butadiynyl group, a phenylethynyl group, and a naphthylethynyl group.

[0031] In formula (4c), R is a divalent group selected from a single bond, a divalent hydrocarbon group having 1 to 21 carbon atoms, -CO-, -O-, -S-, -SO2-, and -C(CF3)2-.

[0032] The divalent hydrocarbon group having 1 to 21 carbon atoms is preferably an alkylene group having 1 to 21 carbon atoms or an arylene group having 6 to 21 carbon atoms, and may be linear, branched, or cyclic, and examples thereof include -CH2-, -C(CH3)2-, -CH(CH3)-, -CHPh-, -C(CH3)Ph-, -C(CH3)(C2H5)-, -C(Ph)2-, -C2H4-, -C3H6-, -C4H8-, 1,1-cyclopentylene group, 1,1-cyclohexylene group, 1,1-cycloheptylene group, methyl-1,1-cyclohexylene group, 1,1-cyclononylene group, 1,1-cyclooctylene, and the like. Examples of the aryl group include, but are not limited to, 3,3,5-trimethyl-1,1-cyclohexylene, 1,1-cyclodecylene, 1,1-cyclododecylene, 1,2-cyclopentylene, 1,2-cyclohexylene, 1,3-cyclopentylene, 1,3-cyclohexylene, 1,4-cyclohexylene, 1,2-phenylene, 1,3-phenylene, 1,4-phenylene, 1,2-xylylene, 1,4-xylylene, tetrahydrodicyclopentadienylene, tetrahydrotricyclopentadienylene, and 1,1-fluorenediyl. Ph represents a phenyl group (-CH), and the phenyl group may have a substituent as long as the total number of carbon atoms is 21 or less.

[0033] Examples of bifunctional epoxy resins include bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol E diglycidyl ether, bisphenol Z diglycidyl ether, bisphenol S diglycidyl ether, bisphenol AD ​​diglycidyl ether, bisphenol acetophenone diglycidyl ether, bisphenol trimethylcyclohexane diglycidyl ether, bisphenol fluorene diglycidyl ether (e.g., ZX-1201 (manufactured by Nippon Steel Chemical & Material Co., Ltd.)), biscresol fluorene diglycidyl ether, tetramethyl bisphenol A diglycidyl ether, tetramethyl bisphenol F diglycidyl ether, tetra-t-butyl bisphenol A diglycidyl ether, tetramethyl bisphenol S diglycidyl ether, dihydroxydiphenyl ether diglycidyl ether, thio ... Examples of epoxy resins that can be used include bisphenol type epoxy resins such as phenol diglycidyl ether and tetrabromobisphenol A diglycidyl ether; biphenol type epoxy resins such as biphenol diglycidyl ether, tetramethylbiphenol diglycidyl ether, dimethylbiphenol diglycidyl ether and tetra-t-butylbiphenol diglycidyl ether; benzenediol type epoxy resins such as hydroquinone diglycidyl ether, methylhydroquinone diglycidyl ether, dibutylhydroquinone diglycidyl ether, resorcinol diglycidyl ether and methylresorcinol diglycidyl ether; dihydroxyanthracene diglycidyl ether, hydroanthrahydroquinone diglycidyl ether, dihydroxynaphthalene diglycidyl ether, bisnaphthol fluorene diglycidyl ether, and diphenyldicyclopentadiene type epoxy resins.

[0034] Further examples of the bifunctional epoxy resin include bifunctional epoxy resins in which hydrogen has been added to the aromatic ring of the above-mentioned bifunctional epoxy resins, glycidyl ester type epoxy resins produced from various dicarboxylic acids such as adipic acid, succinic acid, phthalic acid, tetrahydrophthalic acid, methylhexahydrophthalic acid, terephthalic acid, isophthalic acid, orthophthalic acid, biphenyldicarboxylic acid, and dimer acid, and epihalohydrin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, polytetramethylene glycol diglycidyl ether, 1,5-pentanediol diglycidyl ether, polypentamethylene glycol diglycidyl ether, 1,5-pentanediol diglycidyl ether, polypentamethylene glycol diglycidyl ether, 1,6-pentanediol diglycidyl ether, 1,7-pentanediol diglycidyl ether, 1,8-pentanediol diglycidyl ether, 1,9-pentanediol diglycidyl ether, 2,3-pentanediol diglycidyl ether, 2,4-pentanediol diglycidyl ether, 2,5-pentanediol diglycidyl ether, 2,6-pentanediol diglycidyl ether, 2,7-pentanediol diglycidyl ether, 2,8-pentanediol diglycidyl ether, 2,9 ...9-pentanediol di Examples of the epoxy resins include (poly)alkylene glycol type epoxy resins consisting only of a chain structure, such as 1,6-hexanediol diglycidyl ether, polyhexamethylene glycol diglycidyl ether, 1,7-heptanediol diglycidyl ether, polyheptamethylene glycol diglycidyl ether, 1,8-octanediol diglycidyl ether, 1,10-decanediol diglycidyl ether, and 2,2-dimethyl-1,3-propanediol diglycidyl ether; alkylene glycol type epoxy resins having a cyclic structure, such as 1,4-cyclohexanedimethanol diglycidyl ether; aliphatic cyclic epoxy resins; and phosphorus-containing bifunctional epoxy resins (for example, FX-305 (manufactured by Nippon Steel Chemical & Material Co., Ltd.), diphenylphosphinyl hydroquinone diglycidyl ether, etc.).

[0035] For improving the heat resistance of fiber-reinforced plastics, dihydroxynaphthalene diglycidyl ether, bisphenol fluorene diglycidyl ether, biscresol fluorene diglycidyl ether, and bisnaphthol fluorene diglycidyl ether are preferred, and bifunctional epoxy resins having a fluorene ring structure such as bisphenol fluorene diglycidyl ether, biscresol fluorene diglycidyl ether, and bisnaphthol fluorene diglycidyl ether are more preferred. For imparting flame retardancy, tetrabromobisphenol A diglycidyl ether and phosphorus-containing bifunctional epoxy resins are preferred, and phosphorus-containing bifunctional epoxy resins are more preferred.

[0036] The difunctional epoxy resin used in the epoxy resin composition of the present invention is mainly composed of difunctional components. If monofunctional impurities are contained in a bifunctional epoxy resin, the molecular weight after polymerization will not increase, and the mechanical properties of the resulting thermoplastic resin product may deteriorate. Therefore, it is preferable that the monofunctional impurities are 2% by weight or less relative to the bifunctional epoxy resin. When trifunctional or higher impurities are contained in a bifunctional epoxy resin, the impurities tend to form crosslinked structures, which may lead to increased dispersion of the polymer and gelation, resulting in loss of thermoplasticity. Therefore, it is preferable that the amount of trifunctional or higher impurities is 1% by weight or less relative to the bifunctional epoxy resin.

[0037] The difunctional epoxy resin used in the present invention may, for example, be an epoxy resin obtained by reacting a difunctional phenol compound with epihalohydrin in the presence of an alkali metal compound. Examples of epihalohydrin include epichlorohydrin and epibromohydrin.

[0038] Examples of bifunctional phenolic compounds include bisphenols such as bisphenol A, bisphenol F, bisphenol E, bisphenol Z, bisphenol S, bisphenol AD, bisphenolacetophenone, bisphenoltrimethylcyclohexane, bisphenolfluorene, biscresolfluorene, tetramethylbisphenol A, tetramethylbisphenol F, tetra-t-butylbisphenol A, tetramethylbisphenol S, dihydroxydiphenylether, dihydroxydiphenylmethane, bis(hydroxyphenoxy)benzene, thiodiphenol, and dihydroxystilbene; biphenols such as biphenol, tetramethylbiphenol, dimethylbiphenol, and tetra-t-butylbiphenol; benzenediols such as hydroquinone, methylhydroquinone, dibutylhydroquinone, resorcin, and methylresorcin; dihydroxyanthracene, dihydroxynaphthalene, and dihydroanthrahyde; 10-(2,5-dihydroxyphenyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(2,7-dihydroxy-1-naphthyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(1,4-dihydroxy-2-naphthyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(2,5-dihydroxyphenyl)-8-benzyl-9,10-dihydro-9-oxa-1 Examples of phosphorus-containing phenols include 0-phosphaphenanthrene-10-oxide, 10-(2,7-dihydroxy-1-naphthyl)-8-benzyl-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, diphenylphosphinylhydroquinone, diphenylphosphinyl-1,4-dioxynaphthalene, 1,4-cyclooctylenephosphinyl-1,4-phenyldiol, and 1,5-cyclooctylenephosphinyl-1,4-phenyldiol. 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.

[0039] In the reaction between the bifunctional phenol compound and epihalohydrin to obtain the starting bifunctional epoxy resin, an alkali metal compound is used in an amount of 0.80 to 1.20 times by mole, preferably 0.85 to 1.05 times by mole, based on the functional group in the bifunctional phenol compound. If the amount is less than this, the amount of residual hydrolyzable chlorine increases, which is not preferable. The alkali metal compound is used in the form of an aqueous solution, an alcohol solution, or a solid.

[0040] In the epoxidation reaction, an excess amount of epihalohydrin is used relative to the bifunctional phenol compound. Usually, 1.5 to 15 times the molar amount of epihalohydrin is used relative to 1 mole of the functional group in the bifunctional phenol compound, preferably 2 to 10 times the molar amount, more preferably 5 to 8 times the molar amount. If the amount is more than this amount, the production efficiency decreases, and if it is less than this amount, the amount of high molecular weight epoxy resin produced increases, and it may become unsuitable as a raw material.

[0041] The epoxidation reaction is usually carried out at a temperature of 120° C. or less. 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 less, and more preferably 85° C. or less.

[0042] When a bifunctional phenol compound is reacted with epihalohydrin, m usually becomes greater than 0. In order to make m 0, an epoxy resin produced by a known method can be highly purified by a technique such as distillation or crystallization, or a bifunctional phenol compound can be allylated and then epoxidized by oxidizing the olefin moiety.

[0043] In the compound represented by general formula (1) used in the epoxy resin composition of the present invention, Q is an unsaturated heterocyclic ring-containing acyl group having 5 to 20 carbon atoms. In formula (1), 5 mol % or more of Q is an unsaturated heterocyclic ring-containing acyl group having 5 to 20 carbon atoms, and the rest is a hydrogen atom. By having 5 mol % or more of the acyl group, it is preferable that the polymerized product has sufficient strength because it contributes to suppressing gel generation. Here, the compound represented by general formula (1) may be a mixture of two or more selected from a diester compound in which both Qs are the acyl group, a monoester compound in which one is the acyl group and the other is a hydrogen atom, and a diol compound in which both Qs are hydrogen atoms. The compound represented by general formula (1) is called a diester compound. The diester compound may be a diester compound in which both Qs are the acyl group, or the main component (preferably 5 mol % or more, more preferably 50 mol % or more, even more preferably 70 mol % or more, particularly preferably 90 mol % or more) is the compound (mixture). That is, the molar ratio of the acyl group to the hydrogen atom (acyl group / hydrogen atom) is 100 / 0 to 5 / 95. When the monoester compounds and diol compounds having one or less functionalities are contained, the molecular weight after polymerization tends not to increase, and the mechanical properties of the produced thermoplastic resin may become insufficient. Therefore, it is preferable that the amount of these compounds having one or less functionalities is 2% by weight or less in the compound represented by the general formula (1). When trifunctional or higher impurities are contained, the impurities tend to form crosslinked structures as starting points, which may lead to increased dispersion of the polymer and gelation, resulting in loss of thermoplasticity. Therefore, the amount of trifunctional or higher impurities is preferably 1% by weight or less relative to the compound represented by general formula (1).

[0044] Regarding impurity components that do not have active groups that react with either the bifunctional epoxy resin or the compound represented by general formula (1) and do not inhibit the polymerization reaction by themselves, if the amount is large, there is a risk that the molecular weight after polymerization will become small. Therefore, it is preferable that the amount of each of the bifunctional epoxy resin and the compound represented by general formula (1) is 2% by weight or less. The total amount of impurity components in the compound represented by general formula (1) is preferably 5% by weight or less, more preferably 3% by weight or less.

[0045] In the present invention, the compound represented by the above general formula (1) can be obtained, for example, by acylation of a diol compound having an X group and two hydroxy groups with an acid component such as an organic acid containing an unsaturated heterocycle, an acid anhydride of an organic acid containing an unsaturated heterocycle, an ester of an organic acid containing an unsaturated heterocycle, a halide of an organic acid containing an unsaturated heterocycle, or an ester of an organic acid containing an unsaturated heterocycle, etc. Acylation may be performed not only by direct esterification but also by a method such as transesterification.

[0046] Examples of the unsaturated heterocyclic organic acid include furan carboxylic acid, thiophene carboxylic acid, and pyridine carboxylic acid. Examples of the anhydrides of the unsaturated heterocyclic organic acid include bis(2-furan carboxylic acid) anhydride and bis(2-thiophene carboxylic acid) anhydride. Examples of the esters of the unsaturated heterocyclic organic acid include ethyl 2-furan carboxylate and methyl 2-thiophene. Examples of the halides of the unsaturated heterocyclic organic acid include 2-furan carboxylic acid chloride and 2-thiophene acid chloride.

[0047] As the unsaturated heterocycle-containing compound used for esterification, preferred are halides of unsaturated heterocycle-containing organic acids such as 2-furancarboxylic acid chloride and 2-thiophenecarboxylic acid chloride, and acid anhydrides of unsaturated heterocycle-containing organic acids such as bis(2-furancarboxylic) anhydride and bis(2-thiophenecarboxylic) anhydride. Of these, unsaturated heterocycle-containing acid anhydrides such as bis(2-furancarboxylic) anhydride and bis(2-thiophenecarboxylic) anhydride are more preferred in order to avoid the need for washing with water after esterification and to avoid the inclusion of halogens, which are undesirable in electrical material applications.

[0048] The unsaturated heterocycle-containing acyl group (R 0 -CO-) is represented by the following formulas (2a) to (2f), and specific examples include the following formulas (3a) to (3c). [ka]

[0049] The unsaturated heterocyclic ring-containing acyl group (R 0 -CO-), R 0 As the unsaturated heterocyclic substituent having 4 to 19 carbon atoms, a furyl group having 4 carbon atoms (the above formula (2a), W = oxygen atom (O)), a thienyl group having 4 carbon atoms (the above formula (2a), W = sulfur atom (S)), a pyran skeleton substituent having 5 carbon atoms (the above formula (2b), W = O), a thiopyran skeleton substituent having 5 carbon atoms (the above formula (2c), W = S), a pyridyl group having 5 to 12 carbon atoms (the above formula (2d)), an azanaphthyl group (the above formula (2e)), an azaanthracenyl group (the above formula (2f)), and the like are preferred. Among these, a furyl group (the above formula (3a)), a thienyl group (the above formula (3b)), and a pyridyl group (the above formula (3c)) are preferred, and a furyl group (the above formula (3a)) and a thienyl group (the above formula (3b)) are particularly preferred.

[0050] In the epoxy resin composition of the present invention, a part of the compound represented by the above general formula (1) may be replaced with a diol compound in order to adjust the viscosity, solubility, reactivity, and physical properties of the polymer. By making a plurality of components compatible with each other, it is expected that the effect of suppressing reprecipitation due to crystallization and improving solubility can be expected.

[0051] The diol compound having an X group is not particularly limited as long as it is a compound having two hydroxyl groups. For example, a bifunctional phenol compound having two phenolic hydroxyl groups, a dialcohol compound such as benzene dimethanol having two alcoholic hydroxyl groups, and a monoalcohol monophenol compound such as hydroxybenzyl alcohol having one phenolic hydroxyl group and one alcoholic hydroxyl group are included, and a bifunctional phenol compound is preferred from the viewpoint of reactivity. The X group is a divalent group that is a residual skeleton obtained by removing two hydroxyl groups from these diol compounds. As the bifunctional phenol compound, a bisphenol compound or a biphenyl compound is preferred. Examples of bisphenol compounds include bisphenol A, bisphenol acetophenone (e.g., BisP-AP (manufactured by Honshu Chemical Industry Co., Ltd.)), bisphenol AF (e.g., BIS-AF (manufactured by Central Glass Co., Ltd.)), bisphenol AD, bisphenol B, bisphenol BP, bisphenol C (e.g., S-BOC (manufactured by Honshu Chemical Industry Co., Ltd.)), bisphenol E (e.g., Bis-E (manufactured by Honshu Chemical Industry Co., Ltd.)), bisphenol F, bisphenol G, bisphenol M, bisphenol S (e.g., BPS (manufactured by Nisso Metal Chemical Co., Ltd.)), bisphenol P, bisphenol PH, bisphenol C, bisphenol D, bisphenol E, bisphenol F, bisphenol G, bisphenol M, bisphenol S (e.g., BPS (manufactured by Nisso Metal Chemical Co., Ltd.)), ... Examples of the biphenol compounds include cyclohexane (e.g., Bis-Z (manufactured by Honshu Chemical Industry Co., Ltd.)), bisphenol methylcyclohexane (e.g., BisP-3MZ (manufactured by Honshu Chemical Industry Co., Ltd.)), bisphenol trimethylcyclohexane (e.g., BisP-HTG (manufactured by Honshu Chemical Industry Co., Ltd.)), bisphenol cyclododecane (e.g., BisP-CDE (manufactured by Honshu Chemical Industry Co., Ltd.)), bisphenol fluorene (e.g., BPF (manufactured by Osaka Gas Chemical Co., Ltd.)), biscresol fluorene (e.g., BCF (manufactured by Osaka Gas Chemical Co., Ltd.), BisOC-FL (manufactured by Honshu Chemical Industry Co., Ltd.), and tetramethyl bisphenol F. Examples of biphenol compounds include biphenol, dimethyl biphenol, and tetramethyl biphenol.Other bifunctional phenol compounds include, for example, benzenediols such as hydroquinone, methylhydroquinone, dibutylhydroquinone, resorcin, methylresorcin, catechol, and methylcatechol; naphthalenediols such as naphthalenediol; thiodiphenol; and dihydroxydiphenyl ether. For the purpose of imparting flame retardancy, phosphorus-containing phenolic compounds such as 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO-HQ), 10-(2,7-dihydroxynaphthyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO-NQ), 10-(1,4-dihydroxy-2-naphthyl)-10H-9-oxa-10-phosphaphenanthrene-10-oxide, diphenylphosphinyl hydroquinone, diphenylphosphinyl-1,4-dioxynaphthalene, 1,4-cyclooctylenephosphinyl-1,4-phenyldiol, and 1,5-cyclooctylenephosphinyl-1,4-phenyldiol may be used. These phenol compounds may be unsubstituted or may have an alkyl group, an aryl group or an aralkyl group having 1 to 10 carbon atoms as a substituent on the aromatic ring. From the viewpoint of heat resistance, bisphenol trimethylcyclohexane, bisphenol fluorene, biscresol fluorene, DOPO-HQ and DOPO-NQ are preferred.

[0052] When the epoxy resin composition of the present invention contains a diol compound, the ratio of the diol compound is preferably 40% by weight or less, more preferably 5 to 20% by weight, based on the total weight of the composition. If the ratio of the diol compound exceeds 40% by weight, the ratio of the diol compound becomes high, and there is a risk of a large amount of gel being generated.

[0053] In the epoxy resin composition of the present invention, the ratio of the compound represented by general formula (1) (including a diol compound) is 0.90 to 1.10 mol, preferably 0.95 to 0.99 mol, and more preferably 0.96 to 0.98 mol, relative to 1.00 mol of the bifunctional epoxy resin. In the epoxy resin composition of the present invention, the bifunctional epoxy resin and the compound represented by general formula (1) react successively to form a linear structure, thereby exhibiting thermoplasticity. If the bifunctional epoxy resin is in excess, the polymer will have an epoxy group terminal, and if the compound represented by general formula (1) is in excess, the polymer will have the above-mentioned unsaturated heterocycle-containing group terminal or hydroxyl group terminal, and the reaction will terminate. If the ratio of the compound represented by general formula (1) exceeds 1.10 mol per 1.00 mol of the bifunctional epoxy resin, the polymer will end up with the above-mentioned unsaturated heterocycle-containing group or hydroxyl group, and the reaction will be terminated, so that it may be difficult to increase the molecular weight. On the other hand, if the ratio of the compound represented by general formula (1) is less than 0.90 mol, the excess epoxy group may cause a side reaction, causing the polymer to gel and impairing the thermoplasticity.

[0054] In an epoxy resin composition, if the compound represented by general formula (1) is present in a crystalline state in the epoxy resin, the molar ratio will deviate from the design when viewed microscopically. If the reaction is started in this state, the polymerization may not proceed sufficiently. In order to allow the polymerization to proceed sufficiently, an epoxy resin composition in which the compound represented by general formula (1) and the bifunctional epoxy resin are mutually and uniformly compatible is preferred. In addition, it is desirable that the epoxy resin composition before blending with reinforcing fibers, etc., is completely dissolved or in a uniform liquid state, but for example, when the molten mixture is poured into a glass petri dish to a thickness of 2 mm without any air bubbles and the haze value in the thickness direction is measured, if the haze value in the thickness direction is less than 30%, it is judged that the composition has dissolved to a level that does not affect the polymerization reaction or has become a uniform liquid state. The haze value is more preferably less than 20%, and even more preferably less than 10%.

[0055] The epoxy resin composition of the present invention contains a polymerization catalyst as an essential component. Specific examples of the polymerization catalyst include amine compounds such as 4-dimethylaminopyridine, triethylamine, and tributylamine, imidazole compounds such as 4-methylimidazole, 1B2MZ, 1B2PZ, and TBZ (manufactured by Shikoku Chemical Industry Co., Ltd.), phosphorus compounds such as triphenylphosphine, tris(paratolyl)phosphine, tris(orthotolyl)phosphine, and tris(paramethoxyphenyl)phosphine, quaternary ammonium salts such as tetramethylammonium chloride and tetramethylammonium bromide, crown ether complexes such as 18-crown-6 (18-C-6) / AcOK complex and 18-C-6 / KF complex, and metal chlorides. Preferred are amine compounds such as 4-dimethylaminopyridine, triethylamine, and tributylamine, and phosphorus compounds such as triphenylphosphine, tris(paratolyl)phosphine, tris(orthotolyl)phosphine, and tris(paramethoxyphenyl)phosphine.

[0056] The amount of the polymerization catalyst is preferably 0.01% by weight or more and 5% by weight or less based on the total amount of the epoxy resin composition. If it is less than 0.01% by weight, the in-situ polymerization takes too long, which may reduce productivity, and the catalyst may be deactivated for some reason before the target molecular weight is reached. On the other hand, if it exceeds 5% by weight, the polymerization reaction proceeds quickly, but storage stability may be impaired, which may cause problems in process compatibility, and since the catalyst is a component that participates in the reaction but is not incorporated into the skeleton, it may impair the physical properties after polymerization, and is simply expensive, which is economically disadvantageous. More preferably, it is 0.05 to 1.0% by weight.

[0057] The epoxy resin composition of the present invention desirably does not contain an organic solvent, but may contain an organic solvent as a solvent for the polymerization catalyst or for viscosity adjustment, if necessary. The organic solvent is not particularly limited as long as it does not inhibit the reaction between the bifunctional epoxy resin and the compound represented by general formula (1), but hydrocarbons, ketones, and ethers are preferred because of their ease of availability. Specific examples include toluene, xylene, acetone, methyl ethyl ketone, isobutyl ketone, cyclopentanone, cyclohexanone, and diethylene glycol dimethyl ether. However, if a large amount of organic solvent is present, it may inhibit the polymerization reaction, and if the organic solvent remains in the polymer, it may deteriorate the mechanical properties and heat resistance. For this reason, when an organic solvent is blended, its proportion in the epoxy resin composition is 10% by weight or less, preferably 5% by weight or less, and particularly preferably 2% by weight or less. When an organic solvent is blended, the lower limit is not limited, but it is usually preferably contained at 0.01% by weight or more, and more preferably 0.5% by weight or more.

[0058] The epoxy resin composition of the present invention desirably has a low viscosity in order to maintain the impregnation property into the reinforcing fiber. The viscosity when heated to 85°C is preferably 100 Pa·s or less, more preferably 50 Pa·s or less, and even more preferably 10 Pa·s or less. There is no restriction on the lower limit of the viscosity, but it is usually preferably 0.1 Pa·s or more, and more preferably 1 Pa·s or more. In addition, the time until the viscosity measured initially is doubled (viscosity doubling time) is preferably 30 minutes or more, and more preferably 60 minutes or more.

[0059] The progress of polymerization of the epoxy resin composition of the present invention can be judged by the transition of the weight average molecular weight of the polymer. The polymerization temperature is preferably 140 to 180°C, since polymerization does not proceed sufficiently if it is less than 140°C, and crosslinking reaction is promoted if it exceeds 180°C, and the polymerization time is preferably 30 to 180 minutes, since polymerization does not proceed sufficiently if it is less than 30 minutes, and polymerization proceeds to a three-dimensional crosslinked product if it exceeds 180 minutes.

[0060] The weight average molecular weight (Mw) of the polymer obtained by polymerizing the epoxy resin composition of the present invention is 5,000 or more and 200,000 or less. If the weight average molecular weight of the polymer is below the lower limit of the range, it will contain a large amount of compounds that have not been sufficiently polymerized, and there is a risk of the mechanical strength being deteriorated. On the other hand, if the weight average molecular weight of the polymer is above the upper limit of the range, the crosslinking reaction will have progressed, and there is a risk of the thermoplasticity being impaired. The Mw is preferably 10,000 or more and 150,000 or less, more preferably 20,000 or more and 120,000 or less. The epoxy equivalent of the polymer is preferably 2,000 to 80,000 g / eq. If the epoxy equivalent is less than 2,000 g / eq., the polymerization may not proceed sufficiently. The epoxy equivalent is more preferably 2,500 to 40,000 g / eq., further preferably 3,000 to 30,000 g / eq., and particularly preferably 4,000 to 20,000 g / eq.

[0061] The epoxy resin composition of the present invention may contain additives, such as fillers such as fumed silica, flame retardants such as aluminum hydroxide and red phosphorus, modifiers such as core-shell rubber, and viscosity adjusters such as xylene resin.

[0062] The epoxy resin composition of the present invention becomes a thermoplastic plastic by polymerization. This thermoplastic plastic has excellent adhesion to various fibers as a resin component of fiber-reinforced plastics. The reinforcing fiber-containing epoxy resin composition of the present invention can be obtained by mixing or impregnating the above-mentioned epoxy resin composition with reinforcing fibers. The prepreg can be obtained as follows.

[0063] The epoxy resin composition of the present invention is applied to a release-treated paper or plastic film, and a release-treated cover film is applied as necessary to obtain an epoxy resin composition film. The release paper, release plastic film, and cover film can be any known one, and are not particularly limited. The thickness of the epoxy resin composition film is determined by the design thickness and resin ratio of the prepreg, and is usually 1 μm or more and 300 μm or less. If the thickness is less than 1 μm, there is a problem that the opening of the fiber becomes noticeable unless the reinforcing fiber is defibrated cleanly, and if the thickness exceeds 300 μm, it is difficult to uniformly impregnate the reinforcing fiber. The thickness is preferably 5 μm or more and 150 μm or less, and more preferably 10 μm or more and 100 μm or less.

[0064] The reinforcing fibers used in the present invention are intended to reinforce plastics, such as carbon fibers, aramid fibers, and cellulose fibers, and are not particularly limited. The form of the fibers is also not particularly limited, and includes UD sheets, woven fabrics, tows, chopped fibers, nonwoven fabrics, paper, and the like, in which the fibers are aligned. However, from the viewpoint of impregnation, the thickness of each fiber bundle is 1 mm or less, preferably 0.5 mm or less, and more preferably 0.2 mm or less.

[0065] The reinforcing fiber-containing epoxy resin composition or prepreg of the present invention is obtained from the above-mentioned epoxy resin composition and / or epoxy resin composition film and reinforcing fiber. The ratio of reinforcing fiber to epoxy resin composition is preferably 2:8 to 8:2 by weight. If the ratio of reinforcing fiber is too small, the strength required for the fiber-reinforced material may not be fully satisfied, and if the ratio of reinforcing fiber is too large, defects such as voids may occur. EXAMPLES

[0066] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. Unless otherwise specified, "parts" refers to parts by weight, and "%" refers to % by weight.

[0067] The raw materials and catalysts used in the examples are as follows. [Bifunctional epoxy resin] A1: Tetramethylbiphenol type epoxy resin (Mitsubishi Chemical Corporation, YX4000, epoxy equivalent 186, m≒0.05) [ka] A2: Bisphenol A type epoxy resin (Nippon Steel Chemical & Material Co., Ltd., YD-128, epoxy equivalent 186, m≒0.09) [ka] Here, each m has the same meaning as m in the above formula (4b).

[0068] [Compound represented by general formula (1); diester compound] B1: 2-furancarboxylic acid, 4,4'-(3,3,5-trimethylcyclohexylidene)-di-4,1-phenylene ester (Honshu Chemical Industry Co., Ltd., BH-1, active ester group equivalent 249) [ka] B2: 1,1-bis(4-(2-thiophenecarboxyphenyl))-3,3,5-trimethylcyclohexane (active ester group equivalent: 265) obtained in Synthesis Example 1 [ka] B3: 1,1-bis(4-(2-quinolinecarboxyphenyl))-3,3,5-trimethylcyclohexane (active ester group equivalent: 310) obtained in Synthesis Example 3 [ka] B4: 1,1-bis(4-acetoxyphenyl)-3,3,5-trimethylcyclohexane (active ester group equivalent: 197) obtained in Synthesis Example 4 [ka]

[0069] [Bifunctional phenolic compounds] C1: Bisphenol A (manufactured by Nippon Steel Chemical & Material Co., Ltd., hydroxyl equivalent: 114) [ka] C2: 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane (Honshu Chemical Industry Co., Ltd., BisP-HTG, hydroxyl equivalent 155) [ka]

[0070] [Polymerization catalyst] D1: 4-Dimethylaminopyridine (Tokyo Chemical Industry Co., Ltd.)

[0071] [Acid anhydride] E1: Thiophene-2-carboxylic anhydride (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) E2: Acetic anhydride (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) E3: 2-quinolinecarboxylic anhydride obtained in Synthesis Example 2

[0072] The evaluation methods used in the examples are as follows.

[0073] Compatibility (haze value): Whether the compound represented by the general formula (1) is uniformly dissolved in the epoxy resin was judged by the haze value. Specifically, the epoxy resin composition was placed in a colorless transparent glass petri dish to a thickness of 2 mm, and the haze value was evaluated using a haze standard plate manufactured by Murakami Color Research Laboratory as a reference, with a five-level scale of "less than 5% (<5)", "5% to less than 10% (<10)", "10% to less than 20% (<20)", "20% to less than 30% (<30)", and "30% or more (30<)". If the haze value is less than 30%, it can be judged that the compound represented by the general formula (1) is uniformly dissolved in the epoxy resin.

[0074] Epoxy equivalent weight: The measurements were performed in accordance with JIS K7236 and expressed in units of g / eq. Specifically, a potentiometric titrator (HIRANUMA SANGYO CO., LTD., COM-1600ST) was used, chloroform was used as the solvent, a tetraethylammonium bromide acetate solution was added, and a 0.1 mol / L perchloric acid-acetic acid solution was used.

[0075] Weight average molecular weight (Mw): The weight average molecular weight (Mw) was determined by GPC measurement. Specifically, a column (TSKgel SuperH-H, SuperH2000, SuperHM-H, SuperHM-H, all of which are manufactured by Tosoh Corporation) was used in series with the main body HLC8320GPC (manufactured by Tosoh Corporation), and the column temperature was set to 40°C. The eluent was tetrahydrofuran (THF) at a flow rate of 1.0 mL / min, and a differential refractive index detector was used as the detector. The measurement sample was 50 μL of a solid content of 0.1 g dissolved in 10 mL of THF and filtered through a 0.45 μm microfilter. Mw was calculated by conversion from a calibration curve obtained from standard polystyrene (manufactured by Tosoh Corporation, PStQuick A, PStQuick B, PStQuick C). Data processing was performed using GPC8020 model II version 6.00 manufactured by Tosoh Corporation.

[0076] Gel fraction: Approximately 1 g of the sample (resin plate) was weighed out in a 100 mL vial, 50 mL of tetrahydrofuran was added, ultrasonic diffusion was performed at room temperature for 1 hour, and then the plate was left to stand at room temperature for 23 hours or more to dissolve. A 325 mesh wire mesh was dried in an oven at 100 ° C for 1 hour and its weight was measured. The 325 mesh wire mesh was folded into a funnel shape, and the entire sample solution was poured onto the funnel. The vial was washed with tetrahydrofuran until no insoluble matter of the sample remained, and the sample was poured into the funnel. The insoluble matter on the mesh and the mesh were further washed with tetrahydrofuran and then dried in an oven at 100 ° C for 4 hours or more. The dry weight of the mesh was subtracted from the weight of the dried sample and mesh, and this was divided by the weight of the sample to obtain the gel fraction in %. If the gel fraction is 10% or less, the moldability can be judged to be good.

[0077] Heat resistance: The heat resistance of fiber-reinforced plastics was measured in accordance with the IPC-TM-650 2.4.25.c standard. Specifically, a sample (fiber-reinforced plastic) with a thickness of 4 mm and a length and width of 3 mm was measured for two cycles in the range of 20 to 200°C at a temperature increase rate of 10°C / min using a differential scanning calorimeter EXSTAR6000 DSC6200 (manufactured by Hitachi High-Tech Science Corporation), and the midpoint glass transition temperature (Tmg) of the second scan measurement chart was obtained.

[0078] Flexural strength and flexural modulus: The bending strength and bending modulus of fiber reinforced plastic (FRP) were measured in accordance with JIS K7074, with the fiber orientation of the FRP at 90 degrees (perpendicular) to the input of bending load. The test was performed using a Shimadzu Science Autograph AGS-X, with the sample (fiber reinforced plastic) dimensions of 2 mm thick, 100 mm long, and 15 mm wide, a bending span of 70 mm, and a test speed of 1 mm / min.

[0079] Synthesis Example 1 (Synthesis of Ester Compound B2) A glass reaction vessel equipped with a stirrer, a thermometer, a nitrogen gas inlet, a cooling tube, and a dropping device was charged with 50 parts of C2, 154 parts of E1, and 150 parts of pyridine at room temperature, and the mixture was heated to 60°C while stirring under nitrogen gas flow, and reacted for 2 hours. The mixture was then dried under reduced pressure at 130°C and 1.3 kPa (10 torr) for 2 hours to remove pyridine. The mixture was then washed with a large amount of water to obtain 70 parts of 1,1-bis(4-(2-thiophenecarboxyphenyl))-3,3,5-trimethylcyclohexane (B2).

[0080] Synthesis Example 2 In a glass reaction vessel equipped with a stirrer, a thermometer, a nitrogen gas introduction device, a cooling tube, and a dropping device, 195 parts of sodium quinaldate (manufactured by Tokyo Chemical Industry Co., Ltd.), 192 parts of quinaldoyl chloride (manufactured by Sigma-Aldrich Co., Ltd.), and 300 parts of nitroethane (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were charged at room temperature, and the mixture was heated to 110°C while stirring under nitrogen gas flow, and reacted for 3 hours. After that, the mixture was dried under reduced pressure at 120°C and 1.3 kPa (10 torr) for 2 hours, and 292 parts of 2-quinolinecarboxylic anhydride (E3) was obtained.

[0081] Synthesis Example 3 In a glass reaction vessel equipped with a stirrer, a thermometer, a nitrogen gas inlet, a cooling tube, and a dropping device, 100 parts of C2, 106 parts of E3, 102 parts of pyridine, and 100 parts of toluene were charged at room temperature, and the mixture was heated to 60°C while stirring under nitrogen gas flow, and reacted for 2 hours. After that, the mixture was dried under reduced pressure at 115°C and 1.3 kPa (10 torr) for 2 hours, and 200 parts of 1,1-bis(4-(2-quinolinecarboxyphenyl))-3,3,5-trimethylcyclohexane (B3) was obtained.

[0082] Synthesis Example 4 (Synthesis of Ester Compound B4) In a glass reaction vessel equipped with a stirrer, a thermometer, a nitrogen gas inlet, a cooling tube, and a dropping device, 100 parts of C2, 135 parts of E2, and 102 parts of pyridine were charged at room temperature, and the mixture was heated to 60°C while being stirred under nitrogen gas flow, and reacted for 2 hours. After that, the mixture was dried under reduced pressure at 115°C and 1.3 kPa (10 torr) for 2 hours, and 127 parts of 1,1-bis(4-acetoxyphenyl)-3,3,5-trimethylcyclohexane (B4) was obtained.

[0083] Example 1 100 parts of bifunctional epoxy resin A1 and 100 parts of compound B1 represented by general formula (1) were weighed out, pulverized and mixed using a Henschel mixer, and then sealed in a metal can. The metal can was then placed in a hot air circulating oven preheated to 180°C for 30 minutes to dissolve the resin, and then cooled to room temperature to obtain a precursor mixture of an epoxy resin composition. The haze value of the obtained precursor mixture was less than 10%, and it was uniformly dissolved.

[0084] 100 parts of the precursor mixture preheated to 80°C was weighed into a disposable cup, 0.1 parts of polymerization catalyst D1 was added, and the mixture was mixed for 2 minutes under vacuum conditions (vacuum degree 4 kPa) at a rotation speed of 2000 rpm using a planetary centrifugal mixer (Shinki Corporation, Awatori Rentaro, ARV-310). After mixing, the mixture was quickly removed and immediately cooled to 40°C or lower to obtain epoxy resin composition E1. The haze value of the obtained epoxy resin composition E1 was less than 10%, and it was uniformly dissolved.

[0085] The obtained epoxy resin composition E1 was heated again to 80°C and poured into a chrome-plated iron mold container with a clearance of 4 mm set in advance, and thermally polymerized at 180°C for 60 minutes in a hot air circulating oven to obtain a polymerized product (resin plate). The epoxy equivalent of the obtained polymer was 10,000 g / eq., and Mw was 70,000. The gel fraction was 0%.

[0086] In addition, the obtained epoxy resin composition E1 was heated to 80°C, and using an applicator preheated to a predetermined temperature, it was applied to a release paper (casting paper for carbon fiber composite materials, manufactured by Lintec Corporation) as a film substrate to obtain a coating film of a resin film F1. The thickness of the resin composition in the resulting resin film was 45 μm.

[0087] Carbon fibers (T700-12K-50C, manufactured by Toray Industries, Inc.) were arranged in parallel to the resin composition-coated surface of the obtained resin film F1, and the resin composition-coated surface of another resin film was placed on top of it to form a sandwich structure. This was passed through a heated roll at 100°C for impregnation to obtain a unidirectional (UD) prepreg with a resin content Rc of 35%.

[0088] Furthermore, 13 sheets of the obtained UD prepregs were laminated with the same fiber orientation direction, then sandwiched between release films and vacuum pressed at 160°C, 0.1 MPa, and 240 minutes using a vacuum press to obtain a UD fiber-reinforced plastic. The heat resistance of the obtained UD fiber-reinforced plastic was 135°C, the bending strength was 125 MPa, and the bending modulus was 7.0 GPa.

[0089] Examples 2 to 5, Comparative Examples 1 to 4 The ingredients were mixed in the amounts (parts) shown in Table 1, and the same operations as in Example 1 were carried out to obtain a precursor mixture, an epoxy resin composition, a polymer, a resin film, a UD prepreg, and a UD fiber-reinforced plastic. The evaluation results for each are shown in Table 1. When C1 was used, it was added at the stage of preparing the precursor mixture. The "molar ratio" in the table indicates the molar ratio of the compound represented by general formula (1) and the bifunctional phenol compound to 1 mole of the bifunctional epoxy resin.

[0090] [Table 1]

Claims

1. An epoxy resin composition comprising a bifunctional epoxy resin, a compound represented by the following general formula (1), and a polymerization catalyst, An epoxy resin composition, characterized in that the amount of the compound represented by the above general formula (1) is 0.90 to 1.10 mol per mol of a difunctional epoxy resin. 【Chemistry 1】 Here, X is a divalent group. Q is an unsaturated heterocycle-containing acyl group having 5 to 20 carbon atoms or a hydrogen atom, and 5 mol % or more of Q is the above-mentioned acyl group. The compound represented by general formula (1) may be a mixture of two or more selected from a compound in which both Qs are the above-mentioned acyl group, a compound in which one Q is the above-mentioned acyl group, and a compound in which both Qs are hydrogen atoms.

2. 2. The epoxy resin composition according to claim 1, wherein the unsaturated heterocyclic ring-containing acyl group having 5 to 20 carbon atoms is any one of the unsaturated heterocyclic ring-containing acyl groups represented by the following formulas (2a) to (2f): 【Chemistry 2】 Here, R １ ~R ６ are independently a hydrocarbon group having 1 to 6 carbon atoms, n1 is an integer from 0 to 3, n2 is an integer from 0 to 5, n3 is an integer from 0 to 5, n4 is an integer from 0 to 4, n5 is an integer from 0 to 6, and n6 is an integer from 0 to 8. W is an oxygen atom or a sulfur atom.

3. 2. The epoxy resin composition according to claim 1, wherein the content of the polymerization catalyst is 0.001 to 10 parts by weight per 100 parts by weight of the total amount of the bifunctional epoxy resin and the compound represented by general formula (1).

4. 2. The epoxy resin composition according to claim 1, characterized in that it does not contain an organic solvent, or if it contains an organic solvent, the content of the organic solvent is 0.01% by weight or more and 10% by weight or less of the epoxy resin composition, the viscosity at 85°C is 0.1 Pa s or more and 100 Pa s or less, and the bifunctional epoxy resin and the compound represented by general formula (1) are uniformly dissolved in the epoxy resin composition.

5. A reinforcing fiber-containing epoxy resin composition comprising the epoxy resin composition according to any one of claims 1 to 4 and reinforcing fibers.

6. 6. The reinforcing fiber-containing epoxy resin composition according to claim 5, comprising 20 to 80% by weight of carbon fiber as the reinforcing fiber.

7. A prepreg comprising the reinforcing fiber-containing epoxy resin composition according to claim 5.

8. A fiber-reinforced plastic using the reinforcing fiber-containing epoxy resin composition according to claim 5.

9. A fiber reinforced plastic using the prepreg according to claim 7.

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