TW202344544A - Epoxy resin composition, reinforcing fiber-containing epoxy resin composition, prepreg and fiber-reinforced plastic using these, and thermoplastic epoxy resin - Google Patents

Abstract

An object of the present invention is to provide an epoxy resin composition, a reinforcing fiber-containing epoxy resin composition containing the same, a prepreg, and a fiber-reinforced plastic using these, wherein the epoxy resin composition contains a bifunctional epoxy resin, a bifunctional compound and a polymerization catalyst, has a sufficiently long pot life before the reaction, allows the polymerization reaction to proceed sufficiently, and becomes a thermoplastic epoxy resin by the reaction.

The epoxy resin composition contains a difunctional epoxy compound, a difunctional compound, and a polymerization catalyst as essential components, and becomes a thermoplastic epoxy resin through a polymerization reaction, wherein the polymerization catalyst is an N-substituted aminopyridine compound represented by the following formula (1).

In the formula, R¹ and R² are independently a hydrocarbon group having 1 to 12 carbon atoms, and further R¹ and R² may be bonded together to form a heterocyclic ring, and -O-, -NH-, or -NR⁴- may be present as a bond. However, R⁴ is a hydrocarbon group having 1 to 12 carbon atoms. R³ is independently a hydrocarbon group having 1-12 carbon atoms and k is an integer of 0-4.

Description

Epoxy resin compositions, epoxy resin compositions containing reinforced fibers, prepregs and fiber-reinforced plastics using these, and thermoplastic epoxy resins

The present invention relates to epoxy resin compositions, epoxy resin compositions containing reinforced fibers, prepregs, fiber-reinforced plastics using the same, and thermoplastic epoxy resins.

Fiber-reinforced plastic (FRP) exhibits excellent physical properties such as light weight and high strength, and is used in many fields. Among them, those using carbon fibers as reinforcing fibers (CFRP) are known to have particularly excellent mechanical strength.

Because of its excellent balance between price and physical properties, epoxy resin is mainly used as the base material resin of FRP. Among them, Patent Document 1 proposes a method in which an epoxy compound and a compound containing a phenolic hydroxyl group are mixed with reinforcing fibers in advance, and a polymerization contact agent is used. The solvent and reaction retardant are used to polymerize through a complex addition reaction and form fiber-reinforced thermoplastic resin. Patent Document 2 also proposes a bifunctional epoxy compound having a phenolic hydroxyl group, an amine group, a carboxyl group, a thiol group, and an isocyanate group. A bifunctional compound with a functional group in the group consisting of a cyanate ester group undergoes a complex addition reaction. Such epoxy resin is also called in-situ polymerization type thermoplastic epoxy resin, and using this FRP can be expected to have excellent mass production, moldability, and recyclability. In-situ polymerization thermoplastic epoxy resin is impregnated into fibers in a low viscosity state before polymerization, so it has good impregnation properties and can increase the proportion of reinforcing fibers. Compared with general thermosetting epoxy resin, in-situ polymerization thermoplastic epoxy resin The resin has excellent impact strength or toughness.

One of the required characteristics of FRP is to improve heat resistance. If the heat resistance is above 120°C, it can be used to expand the applicable components. Methods for improving the heat resistance of epoxy resin include increasing the cross-linking density and applying a rigid molecular structure to the skeleton. Increasing the cross-linking density is not suitable for in-situ polymerization thermoplastic epoxy resins which are thermoplastic resins. Changing to a rigid skeleton will increase the viscosity of the resin or worsen the compatibility of the reaction components. Therefore, the steps of coating the resin film or impregnating the fiber become difficult, and the reactivity within the fiber is also reduced.

Methods for reducing the viscosity of a resin with a rigid skeleton molecular structure and easing the steps of coating a resin film or impregnating the resin include adding a solvent or raising the resin treatment temperature. The addition of solvent will remain in the polymer, thereby reducing the physical properties of the final product. The increase in processing temperature will accelerate the reaction speed of the resin, so the usable time will be shortened and processing will become difficult.

By reducing the amount of polymerization catalyst added, the usable life of the resin can be extended, but the reactivity will become worse, and in-situ polymerization will be more time-consuming, so there is a risk of lowering productivity, and there is a risk of side reactions before reaching the target molecular weight. Risk of inactivation for any reason.

The example of Patent Document 3 discloses an in-situ polymerization thermoplastic epoxy resin using a phosphine-based polymerization catalyst and raising the Tg to 139°C, but the resin composition contains more than 30 parts by weight. If the solvent remains in the polymer, it may adversely affect the physical properties. Patent Document 4 examines the use of amine catalysts as polymerization catalysts, but there is no description of the usable time limit.

[Prior technical literature]

[Patent Document]

Patent Document 1: Japanese Patent Application Publication No. 2006-321897.

Patent Document 2: International Publication No. 2004/060981.

Patent Document 3: International Publication No. 2006/123577.

Patent Document 4: International Publication No. 2010/079832.

The object of the present invention is to provide an epoxy resin composition, which is a thermoplastic epoxy resin obtained by reacting a bifunctional epoxy resin with a compound having two phenolic hydroxyl groups and/or active ester groups as functional groups in one molecule. In this case, the usable time before reaction can be sufficiently extended and the polymerization reaction can be fully carried out, and an epoxy resin composition containing reinforced fibers, prepregs and fibers using the same are provided. Reinforced plastic.

The present inventors conducted in-depth studies to solve the above problems and found that a thermoplastic epoxy resin can be obtained using a bifunctional epoxy resin and a compound having two phenolic hydroxyl groups and/or active ester groups as functional groups in one molecule as raw materials. In this case, the above problems can be solved by using a specific N-substituted aminopyridine compound as a polymerization catalyst, leading to the completion of the present invention.

That is, the present invention provides an epoxy resin composition containing an epoxy compound (A) having two epoxy groups in one molecule, two phenolic hydroxyl groups in one molecule, and/or an active ester. A compound (B) having a hydroxyl group (acyloxy group) as a functional group and a polymerization catalyst (C) as essential components, and forming a thermoplastic epoxy resin through a polymerization reaction, wherein the polymerization catalyst (C) is as follows N-substituted aminopyridine compounds represented by formula (1),

In the formula, R ¹ and R ² are independently hydrocarbon groups with 1 to 12 carbon atoms. In addition, R ¹ and R ² can be bonded to each other to form a heterocyclic ring, and the bonding bond can be -O-, -NH-, or -NR. ^4- . However, R ⁴ is a hydrocarbon group having 1 to 12 carbon atoms. R ³ is independently a hydrocarbon group having 1 to 12 carbon atoms, and k is an integer from 0 to 4.

Preferably, 0.90 to 1.10 mol of the above-mentioned compound (B) is blended with 1 mole of the above-mentioned epoxy compound (A), and it is preferably blended with 100 parts by weight of the total amount of the epoxy compound (A) and the compound (B). The usage amount of polymerization catalyst (C) is preferably 0.01 to 10 parts by weight.

啉基吡啶、及4-哌

基吡啶所組成的群組。 The polymerization catalyst (C) is preferably selected from the group consisting of 4-(dimethylamino)pyridine, 4-pyrrolidinylpyridine, 4-piperidylpyridine, 4-(4-methylpiperidyl)pyridine, 4-

Phinopyridine, and 4-piperidine

A group consisting of pyridines.

Part or all of the epoxy compound (A) and/or the compound (B) may be a phosphorus-containing compound. In this case, the phosphorus content of the thermoplastic epoxy resin obtained is preferably 1 to 6% by weight.

The epoxy group equivalent weight of the obtained thermoplastic epoxy resin is preferably 4,000 to 200,000 g/eq.

The above-mentioned epoxy resin composition preferably does not contain an organic solvent, or when it contains an organic solvent, the organic solvent content is not less than 0.01% by weight and not more than 10% by weight of the epoxy resin composition, measured when the temperature is heated to 85°C. The viscosity of the oxygen resin composition is 100Pa‧s or less.

Furthermore, the present invention provides a reinforcing fiber-containing epoxy resin composition containing the above-mentioned epoxy resin composition and reinforcing fibers, and also provides a prepreg composed of the above-mentioned reinforcing fiber-containing epoxy resin composition. Moreover, the reinforcing fiber is preferably carbon fiber, and is preferably contained in a proportion of 50 to 80% by weight.

Furthermore, the present invention provides a fiber-reinforced plastic that uses the above-mentioned epoxy resin composition containing reinforced fibers and uses the above-mentioned prepreg.

Furthermore, the present invention provides a thermoplastic epoxy resin obtained from the above-mentioned epoxy resin composition, having a weight average molecular weight of not less than 30,000 and not more than 200,000, and having an impact strength measured by a notched Izod impact test. is 12kJ/m ² or more.

The epoxy resin composition of the present invention can reduce the amount of catalyst added, maintain a longer usable period, and exhibit good reactivity. Therefore, it can be used as an in-situ polymerization type resin composition to provide thermoplastic fiber-reinforced plastic (FRP) with low void content and excellent heat resistance and impact resistance.

The preferred embodiments of the present invention will be described in detail below.

The epoxy resin composition of the present invention contains an epoxy compound (A) having two epoxy groups in one molecule, two phenolic hydroxyl groups and/or active ester groups (acyloxy groups) in one molecule as functional A composition in which a base compound (B) and an N-substituted aminopyridine compound represented by the above formula (1) are used as a polymerization catalyst (C) as essential components, and are heated and polymerized to become a thermoplastic epoxy resin. . The composition may also contain organic solvents, fillers, flame retardants and other additives.

In addition, in this specification, the epoxy compound (A) having two epoxy groups in one molecule may be called "epoxy compound (A)" or "bifunctional epoxy compound (A)". A compound (B) having two phenolic hydroxyl groups and/or active ester groups (acyloxy groups) as functional groups in one molecule may be called "compound (B)" or "bifunctional compound (B)". Thermoplastic epoxy resin is sometimes called "thermoplastic resin".

The epoxy compound (A) used in the epoxy resin composition of the present invention may be an epoxy compound having two epoxy groups in one molecule. The purity of the epoxy compound (A) is preferably 95% or more. When the epoxy compound (A) contains a monofunctional impurity, the molecular weight after polymerization cannot be increased, so the mechanical properties of the resulting thermoplastic resin product may deteriorate. Therefore, the monofunctional impurity is preferably 2% by weight or less based on the epoxy compound (A). When trifunctional or higher impurities are contained, it is easy to form a cross-linked structure using the impurities as a starting point, so the dispersion of the polymer becomes large, and there is a risk of gelation and loss of thermoplasticity. Therefore, the trifunctional or higher functional impurities are preferably 1% by weight or less relative to the epoxy compound (A). If the purity of the epoxy compound (A) is high, positional isomers or oligomers may be contained. Moreover, these epoxy compounds (A) may be used only 1 type or in combination of several types.

Examples of the epoxy compound (A) include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol E type epoxy resin, bisphenol Z type epoxy resin, bisphenol S type epoxy resin, Bisphenol AD type epoxy resin, bisphenol acetophenone type epoxy resin, bisphenol trimethylcyclohexane type epoxy resin, bisphenol fluorine type epoxy resin (such as ZX-1201 (NIPPON STEEL Chemical & Material Co., Ltd. Co., Ltd.), bis-cresol-type epoxy resin (such as OGSOL CG-500 (manufactured by Osaka Gas Chemical Co., Ltd.), etc.), tetramethylbisphenol A-type epoxy resin, tetramethylbisphenol F type epoxy resin (such as YSLV-80XY (manufactured by NIPPON STEEL Chemical & Material Co., Ltd.), etc.), tetrakis-tert-butylbisphenol A type epoxy resin, tetramethylbisphenol S type epoxy resin, Bisphenol epoxy resins such as dihydroxydiphenyl ether type epoxy resin, sulfodiphenol type epoxy resin, tetrabromobisphenol A type epoxy resin; biphenol type epoxy resin, tetramethylbiphenol type epoxy resin Oxygen resin (such as YX-4000 (manufactured by Mitsubishi Chemical Co., Ltd.), etc.), dimethylbiphenol-type epoxy resin, tetrakis-tert-butylbiphenol-type epoxy resin and other diphenol-type epoxy resins; or hydroquinone benzenediol-type epoxy resin, methylhydroquinone-type epoxy resin, dibutylhydroquinone-type epoxy resin, resorcinol-type epoxy resin, methylresorcinol-type epoxy resin, etc. Resin, or dihydroxyanthracene-type epoxy resin, hydroanthrahydroquinone-type epoxy resin, dihydroxynaphthalene-type epoxy resin, bis-naphthol-type epoxy resin, diphenyldicyclopentadiene-type epoxy resin, etc. .

The bifunctional epoxy compound (A) can further include a bifunctional epoxy compound in which hydrogen is added to the aromatic ring of the above bifunctional epoxy compound; a bifunctional epoxy compound composed of adipic acid, succinic acid, phthalic acid, tetrahydrophthalic acid, Epoxy produced from various dicarboxylic acids such as methylhexahydrophthalic acid, terephthalic acid, isophthalic acid, phthalic acid, biphenyl dicarboxylic acid, dimer acid and epihalopropane Propyl ester type epoxy resin; epoxy propylamine type epoxy resin made from amine compounds such as aniline and epihalohydrin; or ethylene glycol diglycidyl ether, polyethylene glycol dialpoxypropyl ether, Propylene glycol diepoxypropyl ether, polypropylene glycol diepoxypropyl ether, 1,4-butanediol diepoxypropyl ether, polytetramethylene glycol diepoxypropyl ether, 1,5-pentanediol Diol diglycidyl ether, polypentamethylene glycol dialpoxypropyl ether, 1,6-hexanediol dialpoxypropyl ether, polyhexamethylene glycol dialpoxypropyl ether , 1,7-heptanediol diepoxypropyl ether, polyheptamethylene glycol diepoxypropyl ether, 1,8-octanediol diepoxypropyl ether, 1,10-decanediol (poly)alkylene glycol type epoxy resin composed only of chain structures such as alcohol dialpoxypropyl ether and 2,2-dimethyl-1,3-propanediol diepoxypropyl ether; 1,4 - Alkylene glycol-type epoxy resins with cyclic structures such as cyclohexane dimethanol diglycidyl ether; aliphatic cyclic epoxy resins; phosphorus-containing bifunctional epoxy resin (such as FX-305 (manufactured by NIPPON STEEL Chemical & Material Co., Ltd.), diphenylphosphinylhydroquinone diepoxypropyl ether, etc.).

In order to improve the heat resistance of the thermoplastic epoxy resin, the preferred ones are dihydroxynaphthalene-type epoxy resin, bisphenol-type epoxy resin, di-cresol-type epoxy resin, and bis-naphthol-type epoxy resin. More preferably, Bi-functional epoxy compounds with a fluorine ring structure such as bisphenol fluorine type epoxy resin, bisphenol fluorine type epoxy resin, bisnaphthol fluorine type epoxy resin, etc. In order to provide flame retardancy, a tetrabromobisphenol A-type epoxy resin or a phosphorus-containing bifunctional epoxy resin is preferred, and a phosphorus-containing bifunctional epoxy resin is more preferred.

In particular, when used in an epoxy resin composition containing reinforcing fibers, it is preferable to contain the epoxy compound (a) represented by the following formula (2). At this time, the epoxy compound (A) preferably contains 50% by weight or more, more preferably 66% by weight or more, still more preferably 75% by weight or more, and particularly preferably 80% by weight or more. The epoxy compound (a) forms a part of the epoxy compound (A).

n is the number of repetitions, and its average value is 0 to 5, preferably 0 to 1. Moreover, the epoxy group equivalent weight of the epoxy compound (a) is preferably 150 to 350 g/eq. The purity of the epoxy compound (a) is preferably 95% or more.

In formula (2), A is a divalent base represented by the following formula (2a).

In formula (2a), X is any one of a single bond, a hydrocarbon group having 1 to 13 carbon atoms, -O-, -CO-, -COO-, -S-, or -SO ₂ -.

The hydrocarbon group with 1 to 13 carbon atoms is preferably an alkylene group with 1 to 9 carbon atoms or an aryl group with 6 to 13 carbon atoms. Examples include: -CH ₂ -, -CH(CH ₃ )-, -C (CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -CHPh-, -C(CH ₃ )Ph-, 1,1-cyclopropyl, 1,1-cyclobutyl, 1,1 -Cyclopentyl, 1,1-cyclohexyl, 4-methyl-1,1-cyclohexyl, 3,3,5-trimethyl-1,1-cyclohexyl, 1,1-cyclohexyl Octyl, 1,1-cyclopentyl, 1,2-ethyl, 1,2-cyclopropyl, 1,2-cyclobutyl, 1,2-cyclopentyl, 1, 2-cyclohexylene, 1,2-phenyl, 1,3-propylene, 1,3-cyclobutyl, 1,3-cyclopentyl, 1,3-cyclohexylene, 1, 3-phenylene, 1,4-butylene, 1,4-cyclohexylene, 1,4-phenylene, 1,1-phenylene, 1,2-xylylene, 1,4- Xylylene, tetrahydrodicyclopentadienylene, tetrahydrotricyclopentadienylene, etc. Furthermore, Ph represents a phenyl group.

Among these, X is preferably a single bond, -O-, -CO-, -COO-, -S-, -SO ₂ -, -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -CHPh-, -C(CH ₃ )Ph-, 1,1-cyclohexyl, 4-methyl-1,1-cyclohexyl, 3,3,5-trimethyl-1, 1-cyclohexyl, 1,4-cyclohexyl, 1,4-phenylene, 1,1-benzoyl, more preferably single bond, -O-, -CO-, -COO-, -S- , -SO ₂ -, -CH ₂ -, -CH(CH ₃ )-, -C(CH ₃ ) ₂ -, -C(CH ₃ )Ph-, 1,1-cyclohexyl, 3,3,5 -Trimethyl-1,1-cyclohexyl, 1,1-benzoyl. Furthermore, Ph represents a phenyl group. Alkylene is meant to include alkylene groups.

Y ¹ is independently any one of an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 10 carbon atoms.

Examples of the alkyl group having 1 to 4 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, second-butyl, isobutyl, and third-butyl.

Examples of the aryl group having 6 to 10 carbon atoms include phenyl, tolyl, ethylphenyl, styryl, n-propylphenyl, isopropylphenyl, mesityl, and naphthyl.

Among these, methyl, ethyl, n-propyl, n-butyl, tert-butyl, phenyl, tolyl, stubble, or naphthyl are preferred, and methyl, ethyl, and n-propyl are more preferred. , n-butyl, tert-butyl, phenyl, or tolyl.

Y ² is independently any one of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 10 carbon atoms, and is preferably a group other than a hydrogen atom. Examples of alkyl groups and aryl groups are the same as the groups exemplified for Y ¹ above. Preferably Y ² is the same as Y ¹ .

Y ³ is independently any one of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an aryl group having 6 to 10 carbon atoms. Examples of alkyl groups and aryl groups are the same as the groups exemplified for Y ¹ . Preferably Y ³ is a hydrogen atom or the same as Y ¹ .

Examples of the epoxy compound (a) include tetramethylbisphenol F-type epoxy resin, tetramethylbiphenol-type epoxy resin, bisphenol-type epoxy resin, and bis-cresol-type epoxy resin.

The bifunctional compound (B) used in the epoxy resin composition of the present invention may be a diphenol compound (B1) having two hydroxyl groups bonded to an aromatic ring, or a diphenol compound (B1) having two hydroxyl groups bonded to an aromatic ring. A diester compound (B2) having a base, or a monoester compound (B3) having one hydroxyl group and one acyloxy group each bonded to an aromatic ring. In addition, the diester compound (B2) and the monoester compound (B3) may be called "ester compounds" without distinction.

The purity of the bifunctional compound (B) is preferably 95% by weight or more. When monofunctional impurities are contained, the molecular weight after polymerization cannot be increased, so the mechanical properties of the produced thermoplastic resin may deteriorate. Therefore, the monofunctional impurity is preferably 2% by weight or less relative to the bifunctional compound (B). When impurities with more than three functions are contained, it is easy to form a cross-linked structure using the impurities as a starting point. In addition to the components of the polymer, The dispersion becomes large, and there is a risk of gelation and loss of thermoplasticity. Therefore, the amount of trifunctional or higher impurities is preferably 1% by weight or less relative to the bifunctional compound (B). If the purity of the bifunctional compound (B) is high, it may contain positional isomers. Moreover, these bifunctional compounds (B) may be used only 1 type or in combination of several types. Moreover, the acyloxy group is represented by R-CO-O-, and R is a hydrocarbon group having 1 to 19 carbon atoms. The hydrocarbon group having 1 to 19 carbon atoms is preferably an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an aralkyl group having 7 to 13 carbon atoms.

The alkyl group having 1 to 12 carbon atoms may be linear, branched, or cyclic. Examples include: methyl, ethyl, n-propyl, isopropyl, n-butyl, and second-butyl. , tert-butyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, cyclopentyl, n-hexyl, isohexyl, cyclohexyl, n-heptyl, cycloheptyl, methylcyclohexyl, n- Octyl, cyclooctyl, n-nonyl, 3,3,5-trimethylcyclohexyl, n-decyl, cyclodecyl, n-undecyl, n-dodecyl, cyclododecyl, etc.

Examples of aryl groups having 6 to 12 carbon atoms include phenyl, tolyl, ethylphenyl, styryl, n-propylphenyl, isopropylphenyl, mesityl, naphthyl, and methylnaphthyl. wait.

Examples of aralkyl groups having 7 to 13 carbon atoms include benzyl, methylbenzyl, dimethylbenzyl, trimethylbenzyl, phenethyl, 2-phenylisopropyl, naphthylmethyl, etc. .

Among these, a acyloxy group having a hydrocarbon group having 1 to 7 carbon atoms is preferred, and an acetyloxy group, a propyloxy group, a butyloxy group, a benzyloxy group, and a methylbenzyl group are more preferred. The acyloxy group is more preferably an acetyloxy group or a benzyloxy group, and particularly preferably an acetyloxy group.

Examples of the diphenol compound (B1) include bisphenol A, bisphenol F, bisphenol E, bisphenol Z, bisphenol S, bisphenol AD, bisphenol AF, bisphenol B, bisphenol BP, and bisphenol C. Bisphenol G, bisphenol M, bisphenol P, bisphenol PH, bisphenol acetophenone, bisphenol trimethylcyclohexane, bisphenol futon, dicresol futon, tetramethylbisphenol A, tetramethyl bisphenol Bisphenol F, tetrabutyl bisphenol A, tetramethyl bisphenol S, Bisphenol compounds such as dihydroxydiphenyl ether, dihydroxydiphenylmethane, bis(hydroxyphenoxy)benzene, thiodiphenol, and dihydroxystilbene, or biphenol, tetramethylbiphenol, and dimethylbiphenol , diphenol compounds such as tetra-tert-butylbiphenol, or benzenediol compounds such as hydroquinone, methylhydroquinone, dibutylhydroquinone, resorcinol, methylresorcinol, or dihydroxyanthracene, Dihydroxynaphthalene, dihydroanthrahydroquinone, etc., or 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, 10-(2,5-dihydroxyphenyl)-8-benzyl-9,10- Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(2,7-dihydroxy-1-naphthyl)-8-benzyl-9,10-dihydro-9-oxo Hetero-10-phosphaphenanthrene-10-oxide, diphenylphosphinylhydroquinone, diphenylphosphinyl-1,4-dioxonaphthalene, 1,4-cyclooctylphosphinyl-1 , 4-phenylglycol, 1,5-cyclooctylphosphinylglycol-1,4-phenylglycol and other phosphorus-containing phenol compounds.

In order to improve the heat resistance of the thermoplastic epoxy resin, dihydroxynaphthalene, bisphenol fume, and dicresol fume are preferred, and bisphenol fume and dicresol fume are more preferred. Especially when used in an epoxy resin composition containing reinforced fibers, a bisphenol compound or a biphenyl compound is preferred. Moreover, a phosphorus-containing phenol compound may be used for the purpose of imparting flame retardancy.

Examples of the diester compound (B2) and the monoester compound (B3) include compounds in which two or one of the hydroxyl groups of the diphenol compound (B1) are substituted with acyloxy groups (active ester). The diester compound (B2) can be obtained by a condensation reaction between a diphenol compound (B1) and a chelating agent such as an anhydride of an organic acid, a halide of an organic acid, or an organic acid. The monoester compound (B3) can be obtained by isolating a mixture of the monoester compound (B3), the diester compound (B2), and the diphenol compound (B1) by adjusting the diphenol compound (B1). B1) Obtained from the molar ratio of the chelating agent during chelation.

Examples of acid components used in the above-mentioned chelation include acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caprylic acid, caprylic acid, lauric acid, stearic acid, oleic acid, benzoic acid, and tert-butylbenzoic acid. , hexahydrobenzoic acid, phenoxyacetic acid, acrylic acid, methacrylic acid and other organic acids; organic acid anhydrides, organic acid halides, or organic acid esters, etc.

Examples of anhydrides of organic acids include acetic anhydride, benzoic anhydride, phenoxyacetic anhydride, and the like.

Examples of esterified products of organic acids include methyl acetate, ethyl acetate, butyl acetate, methyl benzoate, and ethyl benzoate. Examples of halides of organic acids include acetic acid chloride, benzoic acid chloride, phenoxyacetic acid chloride, and the like.

These chelating agents are preferably halides of organic acids such as acetic acid chloride, benzoic acid chloride, and phenoxyacetic acid chloride; or acid halides such as acetic anhydride, benzoic acid anhydride, phenoxyacetic anhydride, or other acid halides or organic acids. The acid anhydride is more preferably an acid anhydride such as acetic anhydride or benzoic anhydride, and more preferably acetic anhydride, in the sense that it does not require water washing after esterification and avoids mixing of halogen, which is undesirable in electronic material applications.

In the epoxy resin composition of the present invention, the ratio of compound (B) to 1.00 mole of epoxy compound (A) is 0.90 to 1.10 mole, preferably 0.95 to 0.99 mole, more preferably 0.97 to 0.98 More.

In the epoxy resin composition of the present invention, the epoxy compound (A) and the compound (B) react sequentially to form a linear structure, thereby exhibiting thermoplasticity. When the epoxy compound (A) is excessive, it becomes an epoxy group terminal. When the compound (B) is excessive, it becomes a phenol group terminal or a acyloxy group terminal, and the reaction ends.

When the ratio of compound (B) exceeds 0.99 mol, the polymer may become phenol group terminal or acyloxy group terminal and the reaction will be terminated, so there is a risk that the polymer cannot be quantified into a high molecular weight. On the other hand, compound (B) When the ratio is less than 0.95 mol, the excess epoxy groups will produce side reactions, so there is a risk of gelation of the polymer and loss of thermoplasticity.

In the epoxy resin composition of the present invention, if compound (B) exists in a crystalline state in the epoxy compound (A), the molar ratio will exceed the design value at a microscopic level. If the reaction starts in this state, polymerization will not proceed sufficiently. In order to fully advance polymerization, an epoxy resin composition in which the compound (B) and the epoxy compound (A) are uniformly miscible with each other is preferred.

In addition, the epoxy resin composition before blending the reinforcing fibers, etc. is preferably completely dissolved or in a uniform liquid state. For example, the molten mixture is placed in a glass plate so that the thickness becomes 2 mm in a bubble-free state. When measuring the haze value in the thickness direction, if the haze value in the thickness direction does not reach 30%, it is judged to be a dissolved or uniform liquid that will not affect the level of polymerization reaction. The haze value is preferably less than 20%, and more preferably less than 10%. In addition, the method for measuring the haze value is based on the conditions described in the examples.

Examples of the diester compound (B2) include compounds represented by the following formula (3).

Here, X, Y ¹ , Y ² and Y ³ are synonymous with X, Y ¹ , Y ² and Y ³ in the above formula (2a).

The diester compound (B2) may be a phosphorus-containing compound, and examples of the phosphorus-containing compound include the diethyl compound of the cyclic phosphorus compound (HCA-HQ) represented by the following formula (4).

From the viewpoint of imparting flame retardancy, the phosphorus content is preferably not less than 1% by weight and not more than 6% by weight, more preferably not less than 1.5% by weight5, based on the total amount of the epoxy compound (A) and the compound (B). % by weight or less, more preferably 2% by weight or more and 4% by weight.

Furthermore, when the amount of impurity components that do not have an active group that reacts with either the epoxy compound (A) or the compound (B) and whose monomer does not hinder the polymerization reaction increases, the molecular weight after polymerization may become smaller. . Therefore, it is preferable that the impurity component is 2% by weight or less with respect to either of the bifunctional epoxy compound (A) and the bifunctional compound (B).

The polymerization catalyst (C) of the epoxy resin composition of the present invention contains at least one N-substituted aminopyridine compound represented by the following formula (1) as an essential component. The N-substituted aminopyridine compound serves as a reaction catalyst between the bifunctional epoxy compound (A) and the bifunctional compound (B).

In formula (1), R ¹ and R ² are independently hydrocarbon groups with 1 to 12 carbon atoms. In addition, R ¹ and R ² can be bonded to each other to form a heterocyclic ring. The bonding bond can be -O-, -NH-. , or -NR ⁴ -. However, R ⁴ is a hydrocarbon group having 1 to 12 carbon atoms, preferably an alkyl group having 1 to 3 carbon atoms.

R ¹ and R ² are preferably an alkyl group having 1 to 3 carbon atoms, or a group having a cyclopentane ring or a cyclohexane ring formed by bonding with each other.

R ³ is independently a hydrocarbon group having 1 to 12 carbon atoms, preferably an alkyl group having 1 to 3 carbon atoms.

The hydrocarbon group having 1 to 12 carbon atoms is the same as that exemplified by R ¹ and R ² when it is not bonded.

k represents the number of substituent R ³ and is an integer from 0 to 4, preferably 0 or 1, more preferably 0.

The substitution position of the N-substituted amino group can be any one of the 2nd position, the 3rd position, and the 4th position of pyridine, preferably the 4th position, and more preferably the compound represented by the following formula (5).

In the formula, R ¹ and R ² are synonymous with R ¹ and R ² in formula (1).

啉基吡啶、3-二甲胺基吡啶、N,N-二乙基-3-吡啶胺、4-二甲胺基吡啶、4-二乙胺基吡啶、4-二丙胺基吡啶、4-二丁胺基吡啶、4-二苄基胺基吡啶、4-二己胺基吡啶、4-二己胺基吡啶、4-二辛胺基吡啶、4-二壬胺基吡啶、4-二癸胺基吡啶、4-十一烷基胺基吡啶、4-十二烷基胺基吡啶、4-二苄基胺基吡啶、4-二苯胺基吡啶、4-吡咯烷基吡啶、4-哌啶基吡啶、4-(4-甲基哌啶基)吡啶、4-

啉基吡啶、4-甲基乙胺基吡啶、4-甲基丙胺基吡啶、4-甲基苄基胺基吡啶、4-甲基苯胺基吡啶、2-甲基-4-(二甲胺基)吡啶、2-乙基-4-(二甲胺基)吡啶、2-苯基-4-(二甲胺基)吡 啶、3-甲基-4-(二甲胺基)吡啶、3-乙基-4-(二甲胺基)吡啶、3-苯基-4-(二甲胺基)吡啶、3,5-二甲基-4-(二甲胺基)吡啶、2,5-二第三丁基-4-(二甲胺基)吡啶、1-(吡啶-4-基)氮雜環辛烷等，較佳為4-二甲胺基吡啶、4-二乙胺基吡啶、4-二丙胺基吡啶、4-二丁胺基吡啶、4-二苄基胺基吡啶、4-二己胺基吡啶、4-二己胺基吡啶、4-二辛胺基吡啶、4-二壬胺基吡啶、4-二癸胺基吡啶、4-十一烷基胺基吡啶、4-十二烷基胺基吡啶、4-二苄基胺基吡啶、4-二苯胺基吡啶、4-吡咯烷基吡啶、4-哌啶基吡啶、4-(4-甲基哌啶基)吡啶、4-

啉基吡啶、4-甲基乙胺基吡啶、4-甲基丙胺基吡啶、4-甲基苄基胺基吡啶，更佳為4-甲基苯胺基吡啶4-(二甲胺基)吡啶(下式(5a))、4-吡咯烷基吡啶(下式(5b))、4-哌啶基吡啶(下式(5c))、4-(4-甲基哌啶基)吡啶(下式(5d))、4-

啉基吡啶(下式(5e))、4-哌

基吡啶(下式(5f))，又更佳為4-(二甲胺基)吡啶、4-吡咯烷基吡啶、4-哌

基吡啶。該等N-取代胺基吡啶系化合物可僅使用1種亦可組合複數種使用。 Examples of the polymerization catalyst (C) include 2-dimethylaminopyridine, 2-pyrrolidinylpyridine, 2-(dimethylamino)-6-methylpyridine, 2-methylethylaminopyridine, 2 -Methylbutylaminopyridine, 2-diethylaminopyridine, 2-methylpropylaminopyridine, 2-pyrrolidinyl-4-methylpyridine, 2-pyrrolidinyl-5-methylpyridine, 2- Pyrrolidinyl-6-methylpyridine, 2-

Phinopyridine, 3-dimethylaminopyridine, N,N-diethyl-3-pyridinamine, 4-dimethylaminopyridine, 4-diethylaminopyridine, 4-dipropylaminopyridine, 4- Dibutylaminopyridine, 4-dibenzylaminopyridine, 4-dihexylaminopyridine, 4-dihexylaminopyridine, 4-dioctylaminopyridine, 4-dnonylaminopyridine, 4-dibutylaminopyridine Decylamine pyridine, 4-Undecylamine pyridine, 4-dodecylamine pyridine, 4-dibenzylaminopyridine, 4-diphenylamine pyridine, 4-pyrrolidinylpyridine, 4- Piperidylpyridine, 4-(4-methylpiperidyl)pyridine, 4-

Phinopyridine, 4-methylethylaminopyridine, 4-methylpropylaminopyridine, 4-methylbenzylaminopyridine, 4-methylanilinopyridine, 2-methyl-4-(dimethylamine base)pyridine, 2-ethyl-4-(dimethylamino)pyridine, 2-phenyl-4-(dimethylamino)pyridine, 3-methyl-4-(dimethylamino)pyridine, 3 -Ethyl-4-(dimethylamino)pyridine, 3-phenyl-4-(dimethylamino)pyridine, 3,5-dimethyl-4-(dimethylamino)pyridine, 2,5 -Di-tert-butyl-4-(dimethylamino)pyridine, 1-(pyridin-4-yl)azepane, etc., preferably 4-dimethylaminopyridine, 4-diethylamino Pyridine, 4-dipropylaminopyridine, 4-dibutylaminopyridine, 4-dibenzylaminopyridine, 4-dihexylaminopyridine, 4-dihexylaminopyridine, 4-dioctylaminopyridine, 4-Dinonylaminopyridine, 4-didecylaminepyridine, 4-Undecylaminopyridine, 4-dodecylaminopyridine, 4-dibenzylaminopyridine, 4-diphenylamine Pyridine, 4-pyrrolidinylpyridine, 4-piperidinylpyridine, 4-(4-methylpiperidinyl)pyridine, 4-

Phinopyridine, 4-methylethylaminopyridine, 4-methylpropylaminopyridine, 4-methylbenzylaminopyridine, more preferably 4-methylanilinopyridine 4-(dimethylamino)pyridine (the following formula (5a)), 4-pyrrolidinylpyridine (the following formula (5b)), 4-piperidinylpyridine (the following formula (5c)), 4-(4-methylpiperidinyl)pyridine (the following Formula (5d)), 4-

Phylylpyridine (the following formula (5e)), 4-piperidine

pyridine (the following formula (5f)), more preferably 4-(dimethylamino)pyridine, 4-pyrrolidinylpyridine, 4-piperidine

pyridine. These N-substituted aminopyridine compounds may be used alone or in combination.

The compounding amount of the polymerization catalyst (C) is preferably not less than 0.01% by weight and not more than 10% by weight relative to the total amount of the epoxy compound (A) and the compound (B). When it does not reach 0.01% by weight, except for poly In addition to the time-consuming reaction, the productivity may be reduced, and the reaction may be deactivated for some reason before reaching the target molecular weight. On the other hand, when it exceeds 10% by weight, the polymerization reaction will proceed rapidly, but on the other hand, it may damage the storage stability and cause problems in process compatibility. It is a component that participates in the reaction but does not enter the skeleton, so There is a risk of impairing the physical properties after polymerization, and because it is simply more expensive, it is also economically disadvantageous. More preferably, it is 0.03 to 5.0% by weight, still more preferably 0.05 to 1.0% by weight.

In the epoxy resin composition of the present invention, other catalysts may be used together with the above-mentioned N-substituted aminopyridine compound. There are no particular restrictions on other catalysts as long as they are catalysts used in the manufacturing method of epoxy resin called "two-stage method". Examples thereof include alkali metal compounds, organophosphorus compounds, tertiary amines, quaternary ammonium salts, cyclic amines, imidazole compounds, and the like. Only one type of these other catalysts may be used, or two or more types may be used in combination. In addition, when used in an epoxy resin composition containing reinforced fibers, it is preferable not to contain other catalysts.

The epoxy resin composition of the present invention preferably does not contain organic solvents, but may also contain organic solvents as a solvent for polymerization catalysts or to adjust viscosity as needed. The organic solvent is not particularly limited as long as it does not hinder the reaction between the epoxy compound (A) and the compound (B). However, in terms of ease of acquisition, hydrocarbon-based solvents, ketone-based solvents, and ether-based solvents are preferred. Specific examples include toluene, xylene, acetone, methyl ethyl ketone, isobutyl ketone, cyclopentanone, cyclohexanone, diethylene glycol dimethyl ether, and the like. However, if a large amount of organic solvent is present in the reaction, the polymerization reaction may be hindered. In addition, if an organic solvent remains in the polymer, mechanical properties or heat resistance will deteriorate. Therefore, when an organic solvent is blended, its proportion is 10% by weight or less in the epoxy resin composition, preferably 5% by weight or less, more preferably 2% by weight or less, and particularly preferably 1.5% by weight or less.

The progress of polymerization of the epoxy resin composition of the present invention can be judged by the change in the weight average molecular weight of the polymer (thermoplastic epoxy resin). When heating for less than 1 hour, reheat The weight average molecular weight tends to increase, and polymerization may not proceed sufficiently. When heating is performed for 1 hour or more, the epoxy group equivalent system hardly increases from the value at the time point of 1 hour, and it can be judged that the polymerization proceeds sufficiently. Therefore, gelation caused by excessive heating or side reactions caused by out of control will not occur, and the standard polymerization conditions for obtaining polymers from epoxy resin compositions to fully progress the polymerization reaction are preferably 130 to 250°C, Heating conditions for more than 1 hour. Here, the physical property values of the polymers in the examples are measured values obtained by polymerizing under heating conditions of 160°C and 1 hour.

The polymerization reaction of fiber-containing resins such as fiber-reinforced epoxy resin composites or prepregs is hindered by the presence of fibers, so polymerization requires about 2 to 4 times the polymerization time as in the case of resin monomers. Therefore, the standard polymerization conditions for fiber-reinforced epoxy resin composites, prepregs, etc. are heating at 160°C for 4 hours.

The weight average molecular weight (Mw) of the polymer obtained by polymerizing the epoxy resin composition of the present invention is 30,000 or more and 200,000 or less. When the weight average molecular weight of the polymer is less than the lower limit of the range, a large amount of compounds that are not sufficiently polymerized may be contained, and the mechanical strength may be deteriorated. On the other hand, when the weight average molecular weight of the polymer exceeds the upper limit of the range, a cross-linking reaction may occur, which may impair thermoplasticity. Mw is preferably from 40,000 to 150,000, more preferably from 50,000 to 100,000.

The epoxy group equivalent weight of the polymer is preferably from 4,000g/eq. to 200,000g/eq. If the epoxy group equivalent weight is less than 4,000 g/eq., polymerization may not proceed sufficiently. When the epoxy group equivalent exceeds 200,000 g/eq., the number of epoxy groups becomes too small, which may adversely affect the adhesion to fibers and the like. The epoxy group equivalent weight is preferably from 10,000g/eq. to 150,000g/eq., more preferably from 20,000g/eq. to 100,000g/eq.

The glass transition temperature (Tg) of the polymer is preferably 120°C or higher, more preferably 130°C or higher.

When using a phosphorus-containing compound as a raw material, the phosphorus content of the polymer is preferably 1.0 to 6.0% by weight, more preferably 1.5 to 5.0% by weight, and even more preferably 2.0 to 4.0% by weight.

The impact strength of the polymer is evaluated by a notched Izod impact test (specifically, the measurement method described in the examples). The impact strength is preferably above 12kJ/m ² .

The epoxy resin composition of the present invention may contain additives. Examples of additives include fillers such as atomized silica, flame retardants such as aluminum hydroxide or red enamel, modifiers such as core-shell rubber, and viscosity adjusters such as xylene resin. From the perspective of stabilizing the polymerization reaction, the additives are preferably blended with those that are different from the resin, but plasticizers and compatible flame retardants can be included within the range that does not affect the reaction.

The epoxy resin composition of the present invention can be polymerized to form a thermoplastic epoxy resin. This thermoplastic epoxy resin is excellent as a resin component of fiber-reinforced plastics.

The epoxy resin composition containing reinforcing fibers of the present invention can be obtained by mixing or impregnating the above-mentioned epoxy resin composition and reinforcing fibers.

The method for impregnating carbon fiber with the epoxy resin composition of the present invention and molding it can use general FRP molding methods such as pultrusion, winding molding, RTM method, VaRTM method, hand deposition method, and PIF method. In addition, the prepreg can be obtained in the following manner.

The epoxy resin composition of the present invention is coated on a release-treated paper or plastic film, and a release-treated protective film is added as needed, thereby obtaining an epoxy resin composition film. The release paper, release plastic film, and protective film can be any publicly known ones and are not particularly limited. The thickness of the epoxy resin composition film is determined based on the design thickness of the prepreg and the resin ratio. Generally, the thickness is between 1 μm and 300 μm. When it is less than 1μm, there are reinforced fibers. If the fiber is not completely defibrated, the pore size of the fiber will be The most obvious problem is that when the thickness exceeds 300 μm, it is difficult to evenly impregnate the reinforcing fibers. The thickness is preferably from 5 μm to 150 μm, and more preferably from 10 μm to 100 μm.

The coating viscosity of the epoxy resin composition of the present invention is preferably 0.1 Pa‧s or more and 100 Pa‧s or less, more preferably 0.5 Pa‧s or more and 70 Pa‧s or less, and still more preferably 1 Pa‧s or more and 50 Pa‧s or less. . When the coating viscosity is less than 0.1Pa‧s, repeated coating is required to obtain the desired resin film thickness. When the coating viscosity exceeds 100 Pa·s, it becomes difficult to apply the resin film uniformly to a desired thickness. In addition, the measurement method is based on the conditions described in the Examples.

The coating temperature of the epoxy resin composition of the present invention is preferably 120°C or lower, more preferably 100°C or lower, and still more preferably 85°C or lower. If the viscosity becomes coatable, there is no lower limit to the coating temperature.

When using a compound with a rigid skeleton to increase the Tg of the polymer, it is necessary to increase the coating temperature in order to adjust the resin viscosity to a suitable one for coating without adding a solvent. When the coating temperature exceeds 120°C, the resin will significantly thicken due to the polymerization reaction, making it difficult to apply it stably.

In the present invention, for an epoxy resin composition in which the Tg of the thermoplastic epoxy resin is 120°C or higher, the temperature at which the viscosity becomes suitable for coating is 85°C as the standard condition.

The viscosity doubling time at 85°C of the epoxy resin composition of the present invention is preferably more than 20 minutes, more preferably more than 30 minutes, and still more preferably more than 60 minutes. There is no upper limit to the optimal viscosity doubling time. When the viscosity doubling time is less than 20 minutes, the viscosity increase during the coating step becomes significant, making it difficult to coat with a stable film thickness.

The reinforcing fibers used in the present invention are not particularly limited as long as they are carbon fibers, amide fibers, cellulose fibers, etc. used to reinforce plastics. In addition, fiber forms include UD sheets with aligned fibers, woven fabrics, rattan, staple fibers, nonwoven fabrics, papermaking, etc., but are not particularly limited. Only, with From the viewpoint of impregnation, the thickness of each fiber bundle is 1 mm or less, preferably 0.5 mm or less, more preferably 0.2 mm or less.

It is preferable to use carbon fiber as reinforcing fiber because it can obtain a composite material with balanced strength and rigidity. The carbon fiber can be either PAN type or pitch type, and PAN type is particularly preferred.

The epoxy resin composition or prepreg system containing reinforced fibers of the present invention can be obtained from the above-mentioned epoxy resin composition and/or epoxy resin composition film and reinforced fibers. In terms of weight ratio, the ratio of reinforcing fiber and epoxy resin composition is preferably 5:5 to 8:2. Regarding the ratio of reinforcing fibers, if there are too few reinforcing fibers, there is a risk that the required strength of the fiber-reinforced material cannot be fully met. If there are too many reinforcing fibers, defects such as voids may occur.

The epoxy resin composition of the present invention has excellent storage stability. Therefore, it can be used in fields such as carbon fiber reinforced resin.

[Example]

The present invention will be described in more detail below based on examples, but the present invention is not limited to the following examples. Unless otherwise specified, "part" means parts by weight, and "%" means weight %.

The raw materials, catalysts, solvents, and reinforcing fibers used in the examples are as follows.

[Epoxy resin]

A1: Tetramethylbiphenol type epoxy resin (manufactured by Mitsubishi Chemical Co., Ltd., YX-4000, epoxy group equivalent: 186).

A2: Bisphenol-type epoxy resin (manufactured by NIPPON STEEL Chemical & Material Co., Ltd., ESF300, epoxy equivalent weight 250).

A3: Bisphenol A-type liquid epoxy resin (manufactured by NIPPON STEEL Chemical & Material Co., Ltd., YD-128, epoxy group equivalent: 188).

[Phenol compounds and ester compounds]

B1: Bisphenol A (manufactured by NIPPON STEEL Chemical & Material Co., Ltd., hydroxyl equivalent: 114).

B2: 4,4'-bis(3,3,5-trimethylcyclohexylene)bisphenol (manufactured by Honshu Chemical Industry Co., Ltd., BisP-HTG, hydroxyl equivalent: 155).

B3: 4,4'-(1-phenylethylene)bisphenol (manufactured by Honshu Chemical Industry Co., Ltd., BisP-AP, hydroxyl equivalent: 145).

B4: 4,4'-cyclododecane-1-ylidene)bisphenol (manufactured by Honshu Chemical Industry Co., Ltd., BisP-CDE, hydroxyl equivalent: 176).

B5: 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (manufactured by Sanko Co., Ltd., HCA-HQ, hydroxyl equivalent 162).

B6: Bifunctional acetylated compound (10-(2,5-diethyloxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10- obtained in Synthesis Example 1 Oxide, phosphorus compound represented by formula (4), phosphorus content 7.6%, acetyl equivalent 204).

[Polymerization Catalyst]

C1: 4-dimethylaminopyridine (made by Tokyo Chemical Industry Co., Ltd., DMAP, formula (5a)).

C2: 4-pyrrolidinylpyridine (manufactured by Tokyo Chemical Industry Co., Ltd., formula (5b)).

(東京化成工業股份有限公司製，式(5f))。 C3: 1-(4-pyridyl)piperdine

(Made by Tokyo Chemical Industry Co., Ltd., formula (5f)).

C4: 2,3-dihydro-1H-pyrrolo-[1,2-a]benzimidazole (manufactured by Shikoku Chemical Industry Co., Ltd., TBZ).

C5: Tris(p-methoxyphenyl)phosphine (manufactured by Bukheung Chemical Industry Co., Ltd., TPAP).

C6: Tris-o-tolylphosphine (manufactured by Bukheung Chemical Industry Co., Ltd., TOTP).

[other]

D: Cyclohexanone (first-grade reagent, manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.).

E: PAN carbon fiber (manufactured by TORAY Co., Ltd., T700-12K-60E).

The evaluation method in the Examples is as follows.

Compatibility:

The haze value is used to determine whether the phenolic compounds and ester compounds are uniformly melted in the epoxy resin. Specifically, the epoxy resin composition was added to a colorless and transparent glass plate so that the thickness became 2 mm. Referring to the haze standard plate produced by Murakami Color Technology Research Institute, "less than 5% (<5)", "5% or more but less than 10% (<10)", "10% or more but less than 20% (<20)", "20% or more but less than 30% (<30)" )", "30% or more (30<)" five-stage evaluation haze value. If the haze value is less than 30%, it can be judged that the phenolic compound and the ester compound are uniformly dissolved in the epoxy resin.

Viscosity and viscosity doubling time:

According to JIS K 6870 standards and JIS K 5600-2-3 standards, the viscosity and viscosity doubling time at 85°C are measured. Measurement was performed with MCR 102 manufactured by Anton-Paar Company. Measure the viscosity when heated to 85°C under the conditions of a 20mm diameter flat plate with a measuring frequency of 3Hz, a load deformation of 1%, and a gap between the plates of 0.5mm. When the temperature is maintained at 85°C, the time until the viscosity becomes twice the initial measured viscosity is measured and used as the viscosity doubling time. If the viscosity does not reach twice the initial value even after being kept warm for more than 60 minutes, it can be judged to have sufficient potential, so the measurement time is until 60 minutes, and this time is recorded as "60<".

Epoxy equivalent weight:

Measured in accordance with JIS K 7236 standards, the unit is expressed in "g/eq." Specifically, a potentiometric titration device was used, chloroform was used as the solvent, a tetraethylammonium bromide acetic acid solution was added, and a 0.1 mol/L perchloric acid-acetic acid solution was used.

Molecular weight:

The weight average molecular weight (Mw) and the number average molecular weight (Mn) were determined by GPC measurement. Specifically, when using the main body HLC8320GPC (manufactured by TOSOH Co., Ltd.) and a column (TSKgelSuperH-H, SuperH2000, SuperHM-H, SuperHM-H, made by TOSOH Co., Ltd.) in series, the column temperature is 40°C . Tetrahydrofuran (THF) was used as the eluent, the flow rate was 0.3 mL/min, and a differential refractive index detector was used as the detector. Measure the sample When 0.1g of solid content is dissolved in 10mL of THF and filtered with a 0.45μm membrane filter, the injection volume is 20μL. Mw and Mn are obtained by converting the calibration curve using standard polystyrene (PStQuick A, PStQuick B, PStQuick C manufactured by TOSOH Co., Ltd.). In addition, the data processing system uses GPC8020 model II Version 6.00 manufactured by TOSOH Co., Ltd.

Glass transition temperature (Tg):

According to the JIS K 7121 standard, the measurement was performed with a differential scanning calorimetry device (EXSTAR6000 DSC6200 manufactured by Hitachi-Hightech Co., Ltd.) at a temperature rise condition of 10°C/min. At this time, the DSC. Temperature representation of Tmg (the middle temperature of the mutation curve of the wiring between the glass state and the rubber state).

Solvent solubility:

Add 1 g of the sample and 50 mL of tetrahydrofuran to a 100 mL sample bottle, conduct ultrasonic diffusion at room temperature for 1 hour, and then let it stand at room temperature for more than 23 hours to dissolve. When the polymer is dissolved in the solvent and no solid matter is observed, the solvent solubility is evaluated as ○. △ when a partially dissolved residue is produced and a gel state is observed. When the polymer is not soluble in the solvent, it is rated as ×.

Impact strength:

Measured in accordance with the notched Izod impact test in accordance with JIS K 7110. As the testing machine, a digital impact testing machine DG-UB type (manufactured by Toyo Seiki Manufacturing Co., Ltd.) was used, and the lifting angle was set to 150°. The hammer system is suitable for those with nominal swing energy of 0.5J, 1J, or 3J. The dimensions of the sample are 4 mm in thickness, 80 mm in length, and 10 mm in width. The notch is processed to become an A-notch. (Width of the notch: 8.0mm, radius: 0.25mm). Let the hammer pendulum fall on the sample, and calculate the impact strength from the measured hammer pendulum angle.

Bending strength and bending elastic modulus:

Measured in the 90-degree direction using a three-point bending test (Method A) in accordance with JIS K 7074 standards. A testing machine (Autograph AGS-X manufactured by Shimadzu Science) was used. The sample dimensions were thickness 2 mm, length 100 mm, width 15 mm, bending interval 70 mm, and the test was performed at a test speed of 1 mm/min.

Synthesis Example 1 (Ester Compound)

In a glass reaction vessel equipped with a stirring device, a thermometer, a nitrogen introduction device, a cooling tube, and a dropping device, 162 parts of bifunctional phenol compound B5, 105 parts of acetic anhydride, and 79 parts of pyridine were added at room temperature while circulating While stirring under nitrogen, the temperature was raised to 60°C and the reaction was carried out for 2 hours. Thereafter, the mixture was dried under reduced pressure for 2 hours at 150° C. and 1.3 kPa (10 torr) to obtain 203 parts of the phosphorus-containing compound B6 represented by the above formula (4).

(precursor mixture)

Measure 722 parts of A1, 971 parts of A2, 500 parts of B1, and 500 parts of B2 respectively, and grind and mix them using a Henschel mixer. Next, an S1KRC kneader (manufactured by Kurimoto Iron Works Co., Ltd.) whose cylinder temperature is preheated to 190°C is used for melt mixing, and the total amount is recovered in a metal can, and is cooled to 85°C while stirring to obtain an epoxy resin composition. Displacement mixture (F1).

Blending is carried out according to the blending amount (parts) of the prescription in Table 1, and the epoxy resin composition precursor mixture (F2 to F7) is obtained through the same procedure. In addition, the "molar ratio" in the table represents the equivalent ratio of the functional groups of the phenolic compound and the ester compound to the epoxy group of the epoxy resin.

Regarding F7, since the epoxy resin is in liquid form, the pre-mixing using a planetary mixer and a three-roller instead of a Henschel mixer is put into the kneader, and the barrel temperature of the kneader is adjusted. Preheat to 120°C and perform melt mixing. The total amount is recovered in a metal can and cooled to 85°C while stirring to obtain an epoxy resin composition precursor mixture (F7).

[Table 1]

Example 1

0.1 part of C1 (polymerization catalyst) was dissolved in 0.2 part of D1 (organic solvent) in advance to obtain a polymerization catalyst solution. 100 parts of the precursor mixture (F1) was added to a planetary mixer set at 85°C, and the previous polymerization catalyst solution was added and mixed. After mixing, the mixture was quickly taken out and immediately cooled to below 40° C. to obtain an epoxy resin composition (G1).

The haze value (compatibility) of the epoxy resin composition (G1) was measured. The result was 5% or more and less than 10% (<10), and it was judged that it was uniformly dissolved. The viscosity measured at 85℃ is 7.5Pa‧s, and the viscosity doubling time is 55 minutes.

The obtained epoxy resin composition G1 was heated to 85°C and stirred, then flowed into an iron chrome-plated mold container with a gap set to 4mm in advance, and thermally polymerized at 160°C for 60 minutes in a hot air circulation oven to obtain a thermoplastic resin. Polymer (H1).

The obtained polymer had Mw of 63,000, Mn of 16,000, and solvent solubility of ○. The epoxy group equivalent, glass transition temperature (Tg) and impact strength were measured, and the results are shown in Table 2.

Examples 2 to 9, Comparative Examples 1 to 7

The epoxy resin composition and polymers (G2 to G16, H2 to H16) were obtained by blending with the blending amounts (parts) of the prescription in Table 2 and operating in the same manner as in Example 1. In addition, G10 to G16 and H10 to H16 are comparative examples.

The physical properties of the obtained epoxy resin composition and polymers (G2 to G16, H2 to H16) were measured in the same manner as in Example 1, and the evaluation results are shown in Table 2.

[Table 2]

Example 10

The release-treated release paper is fixed on a heating plate preheated to 85°C with the release surface facing up, and 100 parts by weight of the epoxy resin composition (G1) obtained in Example 1 is placed on the release paper. , use a rod coater preheated to 85°C, and apply so that the area weight of the resin becomes 79 g/m ² . Immediately after coating, it was removed from the heating plate and air-cooled to obtain an epoxy resin composition sheet.

Next, carbon fiber (E) was bonded to the obtained epoxy resin composition sheet so that the area weight of the fiber became 153 g/m ² , and a hot press preheated to 90° C. was used to apply the surface pressure to 0.5 MPa. pressure, take it out after 1 minute and air-cool, and obtain a prepreg (I1) with Rc=34%.

After stacking 13 pieces so that the alignment directions of the prepreg (I1) and fibers are the same, the release films are attached to the upper and lower sides and sandwiched with aluminum plates with a thickness of 3 mm. After wrapping the aluminum plate sandwiching the prepreg and the connector with a bag film, connect the connector and the vacuum pump to degas the air in the bag film. Place the bag in a hot-air circulation oven preheated to 160°C, maintain vacuum and harden, and form a unidirectional fiber-reinforced plastic (J1) with a thickness of 2 mm. In addition, the hardening conditions are 160°C and 240 minutes.

The molecular weight of the resin component of the obtained unidirectional fiber-reinforced plastic (J1) was measured. The results showed that Mw was 71,000 and Mn was 17,000. The result of measuring the glass transition temperature (Tg) of unidirectional reinforced fiber plastic is 147°C. The results of measuring the bending strength and bending elastic modulus were 76MPa and 6.1GPa.

The obtained unidirectional fiber-reinforced plastic (J1) was cut into 10 mm width × 100 mm length. After leaving it for 10 minutes in a hot air circulation oven preheated to 200°C, the secondary processability was confirmed by hand bending. Easily bended.

Comparative example 8

To 100 parts of the epoxy resin composition (G13) obtained in Comparative Example 1, 20 parts of the organic solvent (D) was added and mixed while preheating to 85°C, thereby obtaining an epoxy resin composition (G17). The viscosity of the epoxy resin composition at 65°C was measured to be 9.5 Pa‧s, and the viscosity doubling time was 50 minutes.

Except that the preheating temperature of the hot plate and rod coater was set to 65°C, the epoxy resin composition sheet, prepreg (I2), and unidirectional fiber-reinforced plastic (J2) were obtained in the same procedure as in Example 10. The same evaluation as in Example 10 was performed. The results are shown in Table 3.

[table 3]

It can be confirmed from Table 3 that when an organic solvent is added to the resin composition in order to adjust the coating viscosity and viscosity doubling time, the polymerizability, heat resistance, and mechanical strength deteriorate.

By using the epoxy resin composition of the present invention, the polymerization reaction can fully proceed even in in-situ polymerization, and a thermoplastic CFRP with high heat resistance and high fiber content can be obtained.

[Industrial availability]

The epoxy resin composition of the present invention can be used as an in-situ polymerization resin composition, and can provide a thermoplastic fiber-reinforced plastic (FRP) with low void content and excellent heat resistance and impact resistance.

Claims (15)

An epoxy resin composition containing an epoxy compound (A) having two epoxy groups in one molecule, a compound (B) having two phenolic hydroxyl groups and/or active ester groups as functional groups in one molecule, and a polymerization catalyst (C) as an essential component, and a thermoplastic epoxy resin is formed by polymerization reaction, wherein the polymerization catalyst (C) contains an N-substituted aminopyridine compound represented by the following formula (1) At least 1 type,

In the formula, R ¹ and R ² are independently hydrocarbon groups with 1 to 12 carbon atoms. In addition, R ¹ and R ² can be bonded to each other to form a heterocyclic ring. The bonding bond can be -O-, -NH-, or - NR ⁴ -, but R ⁴ is a hydrocarbon group with 1 to 12 carbon atoms, R ³ is independently a hydrocarbon group with 1 to 12 carbon atoms, and k is an integer from 0 to 4. The epoxy resin composition according to claim 1, wherein the blending amount of the epoxy compound (A) and the compound (B) is 1 mol relative to the epoxy compound (A), and the compound (B) is 0.90 to 1.10 moles. The epoxy resin composition according to claim 1, wherein 0.01 to 10 parts by weight of the polymerization catalyst (C) is used relative to 100 parts by weight of the total amount of the epoxy compound (A) and the compound (B). The epoxy resin composition according to claim 1, wherein the polymerization catalyst (C) is selected from the group consisting of 4-(dimethylamino)pyridine, 4-pyrrolidinylpyridine, 4-piperidinylpyridine, 4- (4-methylpiperidyl)pyridine, 4-

Phinopyridine, and 4-piperidine

At least one compound in the group consisting of pyridines. The epoxy resin composition according to claim 1, wherein part or all of the epoxy compound (A) and/or the compound (B) is a phosphorus-containing compound. The epoxy resin composition according to claim 5, wherein the obtained thermoplastic epoxy resin has a phosphorus content of 1 to 6% by weight. The epoxy resin composition described in claim 1 does not contain an organic solvent, or when it contains an organic solvent, the content of the organic solvent is not less than 0.01% by weight and not more than 10% by weight of the epoxy resin composition, and is heated to 85 The viscosity at ℃ is above 0.1Pa‧s and below 100Pa‧s. The epoxy resin composition according to claim 1, wherein the epoxy group equivalent weight of the obtained thermoplastic epoxy resin is 4,000 to 200,000 g/eq. An epoxy resin composition containing reinforced fibers contains the epoxy resin composition described in any one of claims 1 to 8, and reinforced fibers. The epoxy resin composition containing reinforcing fibers as described in claim 9, wherein carbon fibers are contained as reinforcing fibers in a proportion of 50 to 80% by weight. A prepreg composed of a mixture containing the epoxy resin composition described in any one of claims 1 to 8 and reinforcing fibers. The prepreg according to claim 11, wherein carbon fiber is contained as reinforcing fiber in a proportion of 50 to 80% by weight. A fiber-reinforced plastic uses the epoxy resin composition containing reinforced fibers described in claim 9. A fiber-reinforced plastic using the prepreg described in claim 11. A thermoplastic epoxy resin obtained from the epoxy resin composition described in any one of claims 1 to 8, with a weight average molecular weight of 30,000 to 200,000, and an impact strength measured by a notched Izod impact test of 12 kJ /m ² or more.