Thermosetting resin composition, cured product thereof, prepreg, fiber-reinforced composite material, and high-pressure gas container

Abstract

Provided are: a thermosetting resin composition containing (A) a polyfunctional epoxy resin, (B) a (meth)acrylate compound that does not have a glycidyl group, (C) a compound that has a (meth)acryloyloxy group and a glycidyl group, (D) an epoxy resin curing agent that includes a boron amine complex, and (E) a thermal radical polymerization initiator; a cured product thereof; a prepreg containing the thermosetting resin composition; a fiber-reinforced composite material; and a high-pressure gas container.

Description

Thermosetting resin composition and cured product thereof, prepreg, fiber-reinforced composite material, and high-pressure gas container

[0001] The present invention relates to a thermosetting resin composition and a cured product thereof, a prepreg, a fiber-reinforced composite material, and a high-pressure gas container.

[0002] In recent years, environmentally friendly natural gas vehicles (CNG vehicles) and fuel cell vehicles (FCVs) have become increasingly popular. Fuel cell vehicles are powered by fuel cells, making it essential to develop hydrogen stations where hydrogen, the fuel used for fueling these vehicles, is compressed to high pressure and filled into the vehicles. Until now, steel tanks have been used as high-pressure gas storage tanks at hydrogen stations for fuel cell vehicles, or as on-board fuel tanks for CNG vehicles and fuel cell vehicles. However, progress has been made in the development of lighter high-pressure gas storage tanks that use resin materials for the tank liner or outer layer. Reducing the weight of on-board fuel tanks has the advantage of improving the fuel efficiency of vehicles equipped with them.

[0003] Pressure vessels such as high-pressure gas storage tanks typically have a metal liner and an outer layer that covers the outer surface of the liner. However, in recent years, in order to produce lighter pressure vessels, the production of pressure vessels with plastic liners and linerless pressure vessels has also been considered.

[0004] A known method for producing a pressure vessel is to manufacture the pressure vessel by filament winding molding using a tow prepreg (also called a towpreg), in which reinforcing fibers are pre-impregnated with an epoxy resin composition.

[0005] Prepregs and curable resin compositions suitable for prepregs have also been studied. For example, Patent Document 1 discloses a prepreg useful for molding high-strength, high-toughness fiber-reinforced plastics, which includes a carbon fiber and a matrix resin. The matrix resin is a curable resin composition containing a bisphenol-type epoxy resin, a difunctional or higher (meth)acrylate compound, and a curing agent containing dicyandiamide and a radical polymerization agent. The cured product of the curable resin composition has a predetermined flexural modulus and elongation at break. Patent Document 2 also discloses a curable resin composition for prepregs useful for molding high-strength, high-toughness fiber-reinforced plastics, which includes two epoxy resins, a difunctional or higher (meth)acrylate compound, and a curing agent that meets predetermined requirements.

[0006] Japanese Patent No. 6993549 Japanese Patent Application Laid-Open No. 2022-27815

[0007] The thermosetting resin composition used as the matrix resin of the prepreg is required to have a long pot life to ensure the long-term storage stability of the prepreg. Furthermore, in order to ensure heat resistance and high toughness in the fiber-reinforced composite material obtained by curing the prepreg, the thermosetting resin composition used as the matrix resin of the prepreg is required to have both a high glass transition temperature and a high elongation percentage in the cured product. However, the techniques disclosed in Patent Documents 1 and 2 have difficulty in satisfying all of these required properties.

[0008] On the other hand, when an attempt is made to improve the elongation percentage of a cured product of a thermosetting resin composition, the tensile stress and tensile modulus of the cured product generally tend to decrease.

[0009] Therefore, an object of the present invention is to provide a thermosetting resin composition which gives a cured product having high glass transition temperature, high elongation, high tensile stress, and high tensile modulus and which has a long pot life; a cured product thereof; a prepreg and a fiber-reinforced composite material each containing the thermosetting resin composition; and a high-pressure gas container.

[0010] The present inventors have found that the above-mentioned problems can be solved by a thermosetting resin composition containing a multifunctional epoxy resin, a (meth)acrylate compound having no glycidyl group, a compound having a (meth)acryloyloxy group and a glycidyl group, a predetermined epoxy resin curing agent, and a thermal radical polymerization initiator. Specifically, the present invention relates to the following: [1] A thermosetting resin composition containing: Component (A): a multifunctional epoxy resin; Component (B): a (meth)acrylate compound having no glycidyl group; Component (C): a compound having a (meth)acryloyloxy group and a glycidyl group; Component (D): an epoxy resin curing agent containing a boron amine complex; and Component (E): a thermal radical polymerization initiator. [2] The thermosetting resin composition according to [1], wherein Component (B) contains Component (B1): poly(butadiene-co-acrylonitrile) having (meth)acryloyloxy groups at both ends. [3] The thermosetting resin composition according to [1] or [2], wherein the component (B) contains a polyfunctional (meth)acrylate having an aromatic ring. [4] The thermosetting resin composition according to any one of [1] to [3], wherein the component (C) contains a compound represented by the following general formula (1): In formula (1), R １１ represents a hydrogen atom or a methyl group. Z represents a single bond, -(CH ２ ) ｍ -O- (where m is a number from 2 to 8), or a divalent group represented by the following general formula (2): In formula (2), R １２ and R １３each independently represents a hydrogen atom or a methyl group. n is a number from 1 to 5. * represents a bond. [5] The thermosetting resin composition according to any one of [1] to [4], wherein the amine component in the boron amine complex is a trialkylamine. [6] A cured product of the thermosetting resin composition according to any one of [1] to [5]. [7] A prepreg comprising the thermosetting resin composition according to any one of [1] to [5] and reinforcing fibers. [8] The prepreg according to [7], wherein the reinforcing fibers are at least one type selected from the group consisting of carbon fibers, glass fibers, and basalt fibers. [9] The prepreg according to [7] or [8], wherein the prepreg is a tow prepreg or a tape prepreg.

[10] A fiber-reinforced composite material which is a cured product of the prepreg according to any one of [7] to [9].

[11] A high-pressure gas container comprising the fiber-reinforced composite material according to

[10] .

[0011] According to the present invention, a thermosetting resin composition can be provided which gives a cured product having a high glass transition temperature, elongation, tensile stress, and tensile modulus, and which has a long pot life; a cured product thereof; a prepreg containing the thermosetting resin composition; a fiber-reinforced composite material; and a high-pressure gas container.

[0012] [Definitions] In this specification, the term "(meth)acryloyloxy group" includes both an acryloyloxy group and a methacryloyloxy group. The same applies to "(meth)acrylate", "(meth)acrylic acid", etc. In this specification, "room temperature" means 23°C unless otherwise specified.

[0013] [Thermosetting resin composition] The thermosetting resin composition of the present invention (hereinafter also simply referred to as "the composition of the present invention") contains: Component (A): a polyfunctional epoxy resin, Component (B): a (meth)acrylate compound having no glycidyl group, Component (C): a compound having a (meth)acryloyloxy group and a glycidyl group, Component (D): an epoxy resin curing agent containing a boron amine complex, and Component (E): a thermal radical polymerization initiator. Because the composition of the present invention has the above configuration, a cured product having high glass transition temperature (Tg), elongation, tensile stress, and tensile modulus can be obtained, and the composition also has a long pot life.

[0014] The reason why the above-mentioned effects are achieved in the present invention is unclear, but is thought to be as follows. The thermosetting resin composition of the present invention contains a polyfunctional epoxy resin (A), a (meth)acrylate compound (B) not having a glycidyl group, and a compound (C) having a (meth)acryloyloxy group and a glycidyl group as thermosetting resins. The epoxy resin curing agent (D) serves as a curing agent for components (A) and (C), and the thermal radical polymerization initiator (E) acts as a thermal radical polymerization initiator for curing components (B) and (C). Thermosetting (epoxy) resin compositions comprising an epoxy resin and an epoxy resin curing agent generally have excellent curability, heat resistance, etc., but the low elongation of the cured product has been a problem for applications requiring high toughness. Furthermore, because epoxy resin compositions typically cure quickly, an improvement in pot life has also been necessary, particularly for use in prepregs stored at room temperature. The inclusion of a boron amine complex in component (D) used in the thermosetting resin composition of the present invention improves pot life. Furthermore, by forming the thermosetting resin composition of the present invention as a hybrid of an epoxy resin curing system of component (A)-component (D) and a (meth)acrylate curing system of component (B)-component (E), the elongation of the cured product is improved compared to a case in which the epoxy resin curing system is used alone, and it is believed that this can also suppress a decrease in the pot life of the composition due to the high reactivity of component (A) with the epoxy resin curing agent. Furthermore, component (C) used in the present invention contains a (meth)acryloyloxy group and a glycidyl group and can react with both component (A) and component (B), thereby acting as a crosslinking agent between component (A) and component (B). This is believed to further improve the tensile stress and tensile modulus of the resulting cured product.

[0015] <Component (A): Polyfunctional Epoxy Resin> The polyfunctional epoxy resin (A) used in the present invention is not particularly limited as long as it is an epoxy resin that does not have a (meth)acryloyloxy group and has two or more epoxy groups. From the viewpoint of improving the Tg, tensile stress, and tensile modulus of a cured product, however, a polyfunctional epoxy resin that contains an aromatic ring or an alicyclic structure in the molecule is preferred.

[0016] Specific examples of the polyfunctional epoxy resin (A) include at least one selected from the group consisting of polyfunctional epoxy resins having glycidylamino groups derived from meta-xylylenediamine, polyfunctional epoxy resins having glycidylamino groups derived from para-xylylenediamine, polyfunctional epoxy resins having glycidylamino groups derived from 1,3-bis(aminomethyl)cyclohexane, polyfunctional epoxy resins having glycidylamino groups derived from 1,4-bis(aminomethyl)cyclohexane, polyfunctional epoxy resins having glycidylamino groups derived from diaminodiphenylmethane, polyfunctional epoxy resins having glycidylamino groups and / or glycidyloxy groups derived from para-aminophenol, polyfunctional epoxy resins having glycidyloxy groups derived from resorcinol, polyfunctional epoxy resins having glycidyloxy groups derived from bisphenol A or hydrogenated products thereof, polyfunctional epoxy resins having glycidyloxy groups derived from bisphenol F or hydrogenated products thereof, and polyfunctional epoxy resins having glycidyloxy groups derived from phenol novolac. The polyfunctional epoxy resins may be used alone or in combination of two or more.

[0017] Among the above, from the viewpoint of improving the Tg, tensile stress, and tensile modulus of the cured product, the polyfunctional epoxy resin (A) is preferably one having as a main component at least one selected from the group consisting of polyfunctional epoxy resins having glycidylamino groups derived from meta-xylylenediamine, polyfunctional epoxy resins having glycidylamino groups derived from para-xylylenediamine, polyfunctional epoxy resins having glycidyloxy groups derived from bisphenol A, and polyfunctional epoxy resins having glycidyloxy groups derived from bisphenol F, and more preferably one having as a main component at least one selected from the group consisting of epoxy resins having glycidyloxy groups derived from bisphenol A and epoxy resins having glycidyloxy groups derived from bisphenol F. Here, the term "main component" means that other components may be contained within the scope of the present invention, and preferably means 50 to 100 mass%, more preferably 70 to 100 mass%, and even more preferably 90 to 100 mass% of the total.

[0018] The polyfunctional epoxy resin having a glycidyloxy group derived from bisphenol A is bisphenol A diglycidyl ether or an oligomer thereof, and is preferably a polyfunctional epoxy resin represented by the following structural formula: (In the above formula, s represents the average number of repeating units and is a number from 0 to 20.) From the viewpoint of improving the Tg, tensile stress, and tensile modulus of the cured product, s in the above formula is preferably 0 to 15, more preferably 0 to 10, even more preferably 0.05 to 10, and still more preferably 0.10 to 8.0. The polyfunctional epoxy resin having a glycidyloxy group derived from bisphenol F is bisphenol F diglycidyl ether or an oligomer thereof, and is preferably a polyfunctional epoxy resin represented by the following structural formula: (In the above formula, t represents the average number of repeating units and is a number from 0 to 20.) From the viewpoint of improving the Tg of the cured product, t in the above formula is preferably 0 to 15, more preferably 0 to 10, and even more preferably 0 to 8.0.

[0019] The polyfunctional epoxy resin (A) may be either a solid epoxy resin or a liquid epoxy resin, but from the viewpoint of easy impregnation into reinforcing fibers when applied to prepregs, it is preferable that the polyfunctional epoxy resin (A) contains a liquid epoxy resin. A "solid epoxy resin" refers to an epoxy resin that does not have fluidity at 25°C, and a "liquid epoxy resin" refers to an epoxy resin that has fluidity at 25°C. From the viewpoint of improving impregnation into reinforcing fibers, the content of the liquid epoxy resin in the polyfunctional epoxy resin (A) is preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 60% by mass or more, still more preferably 70% by mass or more, even more preferably 80% by mass or more, still more preferably 85% by mass or more, and still more preferably 90% by mass or more, but not more than 100% by mass.

[0020] The epoxy equivalent (functional group equivalent) of the polyfunctional epoxy resin (A) is not particularly limited, but from the viewpoint of facilitating impregnation into reinforcing fibers when applied to prepregs, it is preferably 1,500 g / equivalent or less, more preferably 1,200 g / equivalent or less, even more preferably 1,000 g / equivalent or less, still more preferably 800 g / equivalent or less, even more preferably 500 g / equivalent or less, still more preferably 350 g / equivalent or less, and even more preferably 250 g / equivalent or less, and from the viewpoint of improving curing properties, it is preferably 120 g / equivalent or more. When a mixture of two or more epoxy resins is used as the polyfunctional epoxy resin (A), the epoxy equivalent of the polyfunctional epoxy resin (A) means the epoxy equivalent of the mixture.

[0021] As the component (A), a polyfunctional epoxy resin having a glycidyloxy group derived from bisphenol A, commercially available products such as "jER825," "jER827," "jER828," "jER834," "jER1001," and "jER1004," manufactured by Mitsubishi Chemical Corporation, can be used. As the polyfunctional epoxy resin having a glycidyloxy group derived from bisphenol F, commercially available products such as "jER806," "jER806H," "jER807," "jER4005P," "jER4007P," and "jER4010P," manufactured by Mitsubishi Chemical Corporation, can be used.

[0022] <Component (B): (Meth)acrylate Compound Having No Glycidyl Group> Component (B) used in the present invention is a (meth)acrylate compound having no glycidyl group. Component (B) may be any compound having no glycidyl group and at least one (meth)acryloyloxy group. However, from the viewpoint of improving the Tg, elongation, tensile stress, and tensile modulus of the cured product, it preferably contains a polyfunctional (meth)acrylate compound having two or more (meth)acryloyloxy groups. The number of (meth)acryloyloxy groups in the polyfunctional (meth)acrylate compound is preferably 2 to 6, more preferably 2 to 4, even more preferably 2 to 3, and still more preferably 2. If the number of (meth)acryloyloxy groups in the polyfunctional (meth)acrylate compound is 2 or more, it is likely to contribute to improving the Tg, tensile stress, and tensile modulus of the cured product, while if the number is 6 or less, it is possible to suppress a decrease in the elongation of the cured product.

[0023] From the viewpoint of improving the Tg, elongation, tensile stress, and tensile modulus of the cured product, the content of the polyfunctional (meth)acrylate compound in component (B) is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, still more preferably 80% by mass or more, still more preferably 90% by mass or more, still more preferably 95% by mass or more, and still more preferably 98% by mass or more, but is 100% by mass or less.

[0024] From the viewpoint of improving the Tg, elongation, tensile stress, and tensile modulus of the cured product, component (B) preferably contains, as a polyfunctional (meth)acrylate compound, at least one selected from the group consisting of component (B1): poly(butadiene-co-acrylonitrile) having (meth)acryloyloxy groups at both ends; and component (B2): polyfunctional (meth)acrylate having an aromatic ring, and more preferably contains both component (B1) and component (B2).

[0025] (Component (B1): Poly(butadiene-co-acrylonitrile) terminated with (meth)acryloyloxy groups at both ends) From the viewpoint of improving the elongation of the cured product, component (B) preferably contains, as a polyfunctional (meth)acrylate compound, component (B1): poly(butadiene-co-acrylonitrile) terminated with (meth)acryloyloxy groups at both ends. Because component (B1) has a highly flexible structure, it is believed that it can suppress a decrease in elongation even in cured products with a high crosslink density. Component (B1) used in the present invention is a di(meth)acrylate having (meth)acryloyloxy groups at both ends of a main chain containing a copolymer structure of butadiene and acrylonitrile. From the viewpoint of improving the Tg, elongation, tensile stress, and tensile modulus of the cured product, the content of acrylonitrile-derived structural units in component (B1) is preferably 5 to 50% by mass, more preferably 10 to 30% by mass, and even more preferably 10 to 25% by mass. The weight-average molecular weight (Mw) of component (B1) is preferably 1,000 to 30,000, more preferably 2,000 to 10,000, and even more preferably 3,000 to 8,000. An Mw of 1,000 or more contributes to improving the elongation of the cured product, while an Mw of 30,000 or less tends to suppress decreases in the Tg, tensile stress, and tensile modulus of the cured product. Commercially available products of component (B1) include "Hypro 1300X33LC" manufactured by Chori GLEX.

[0026] The content of component (B1) in component (B) is preferably 1 to 70 mass%, more preferably 5 to 70 mass%, even more preferably 10 to 70 mass%, still more preferably 15 to 70 mass%, still more preferably 15 to 60 mass%, still more preferably 15 to 50 mass%, still more preferably 15 to 35 mass%, still more preferably 15 to 25 mass%, and still more preferably 15 to 20 mass%. When the content of component (B1) in component (B) is 1 mass% or more, it is likely to contribute to improving the elongation of the cured product, while when it is 70 mass% or less, it is possible to suppress decreases in the Tg, tensile stress, and tensile modulus of the cured product.

[0027] (Component (B2): Polyfunctional (meth)acrylate having an aromatic ring) From the viewpoint of improving the Tg, elongation, tensile stress, and tensile modulus of the cured product, component (B) preferably contains, as a polyfunctional (meth)acrylate compound, component (B2): a polyfunctional (meth)acrylate having an aromatic ring. The number of (meth)acryloyloxy groups in component (B2) is preferably 2 to 6, more preferably 2 to 4, even more preferably 2 to 3, and still more preferably 2. If the number of (meth)acryloyloxy groups in component (B2) is 2 or more, this tends to contribute to improving the Tg, tensile stress, and tensile modulus of the cured product, while if it is 6 or less, a decrease in the elongation of the cured product can be suppressed.

[0028] The aromatic ring contained in component (B2) may be a single ring or a fused ring, and examples thereof include, but are not limited to, a benzene ring, a naphthalene ring, an anthracene ring, and a tetracene ring. Among these, at least one ring selected from the group consisting of a benzene ring and a naphthalene ring is preferred, and a benzene ring is more preferred. The number of aromatic rings contained in component (B2) may be one or more, and from the viewpoint of improving the Tg, elongation, tensile stress, and tensile modulus of the cured product, it is preferably two or more.

[0029] Specific examples of the polyfunctional (meth)acrylate having an aromatic ring, which is used as component (B2), include polyfunctional (meth)acrylates having a structure derived from biphenol, polyfunctional (meth)acrylates having a structure derived from bisphenol A, polyfunctional (meth)acrylates having a structure derived from bisphenol F, polyfunctional (meth)acrylates having a fluorene structure, and polyfunctional (meth)acrylates having a structure derived from an aromatic hydrocarbon formaldehyde resin, and one or more of these can be used. Among the above, from the viewpoint of improving the Tg, elongation, tensile stress, and tensile modulus of the cured product, component (B2) preferably comprises at least one selected from the group consisting of polyfunctional (meth)acrylates having a structure derived from bisphenol A, polyfunctional (meth)acrylates having a structure derived from bisphenol F, and polyfunctional (meth)acrylates having a structure derived from an aromatic hydrocarbon formaldehyde resin, more preferably at least one selected from the group consisting of polyfunctional (meth)acrylates having a structure derived from bisphenol A and polyfunctional (meth)acrylates having a structure derived from an aromatic hydrocarbon formaldehyde resin, and even more preferably a polyfunctional (meth)acrylate having a structure derived from bisphenol A. The polyfunctional (meth)acrylate may be any of polyester (meth)acrylates having a main skeleton derived from a polyol, epoxy (meth)acrylates having a main skeleton derived from an epoxy compound, and urethane (meth)acrylates having a main skeleton derived from a polyisocyanate, but is preferably at least one selected from the group consisting of polyester (meth)acrylates and epoxy (meth)acrylates.

[0030] The aromatic hydrocarbon-formaldehyde resin is a resin obtained by reacting an aromatic hydrocarbon with formaldehyde. Examples of the aromatic hydrocarbon include at least one selected from the group consisting of benzene, xylene, toluene, mesitylene, pseudocumene, ethylbenzene, propylbenzene, decylbenzene, cyclohexylbenzene, biphenyl, methylbiphenyl, naphthalene, methylnaphthalene, dimethylnaphthalene, ethylnaphthalene, anthracene, methylanthracene, dimethylanthracene, ethylanthracene, and binaphthyl. Preferably, at least one selected from the group consisting of xylene, toluene, and mesitylene is used, and more preferably, xylene. Xylene-formaldehyde resins are also referred to as "xylene resins," toluene-formaldehyde resins as "toluene resins," and mesitylene-formaldehyde resins as "mesitylene resins."

[0031] From the viewpoint of improving the Tg, elongation, tensile stress, and tensile modulus of the cured product, the polyfunctional (meth)acrylate having an aromatic ring used as component (B2) more preferably comprises at least one selected from the group consisting of a compound represented by the following general formula (B2-1), a compound represented by the following general formula (B2-2), a compound represented by the following general formula (B2-3), and a polyfunctional (meth)acrylate having a structure derived from an aromatic hydrocarbon formaldehyde resin, even more preferably comprises at least one selected from the group consisting of a compound represented by the following general formula (B2-1) and a compound represented by the following general formula (B2-2), and even more preferably comprises a compound represented by the following general formula (B2-1): In the formula, R １ and R ２ each independently represents a hydrogen atom or a methyl group, R ３ and R ４ each independently represents a hydrogen atom or a methyl group, k and l each independently represent the number of repeating units and are a number from 0 to 20. In the formula, R １ ~R ４ is the same as above. In the formula, R １ and R ２is the same as above, and R ５ is an alkylene group having 2 to 6 carbon atoms. X is a residue of a diisocyanate, and Y is a residue of a diol. Either X or Y contains an aromatic ring. r represents the number of repeating units and is a number of 1 or more. The r+1 Xs and the r Ys may all be the same or different from one another.

[0032] In the general formula (B2-1), R １ and R ２ is preferably a methyl group, and R ３ and R ４ is preferably a methyl group. From the viewpoint of improving the Tg, elongation, tensile stress, and tensile modulus of the cured product, k and l each independently represent a number from 1 to 15, more preferably from 1 to 10, and even more preferably from 2 to 6. Furthermore, k+l represents a number from 0 to 40, and from the viewpoint of improving the Tg, elongation, tensile stress, and tensile modulus of the cured product, it is preferably a number from 2 to 30, more preferably from 2 to 20, even more preferably from 4 to 20, and still more preferably from 8 to 20.

[0033] As the compound represented by the general formula (B2-1), commercially available products such as "BPE-500" and "BPE-900" manufactured by Shin-Nakamura Chemical Co., Ltd. can be used.

[0034] In the general formula (B2-2), R １ and R ２ is preferably a methyl group, and R ３ and R ４ is preferably a methyl group. Specific examples of the compound represented by general formula (B2-2) include a (meth)acrylic acid adduct of bisphenol A diglycidyl ether [bisphenol A-type epoxy di(meth)acrylate] and a (meth)acrylic acid adduct of bisphenol F diglycidyl ether [bisphenol F-type epoxy di(meth)acrylate], of which bisphenol A-type epoxy di(meth)acrylate is preferred, and bisphenol A-type epoxy dimethacrylate is more preferred.

[0035] In the general formula (B2-3), R １ and R ２ is preferably a methyl group.５ is an alkylene group having 2 to 6 carbon atoms, and the alkylene group may be either a straight chain or a branched chain. ５ is preferably an alkylene group having 2 to 4 carbon atoms, more preferably 2 to 3 carbon atoms.

[0036] X in the general formula (B2-3) is a divalent group and is a residue of a diisocyanate represented by OCN-X-NCO. Examples of the diisocyanate include aliphatic chain diisocyanates such as trimethylene diisocyanate, tetramethylene diisocyanate, 1,3-pentamethylene diisocyanate, 1,5-pentamethylene diisocyanate, hexamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, 2-methyl-1,5-pentamethylene diisocyanate, and 3-methyl-1,5-pentamethylene diisocyanate; 1,3-cyclopentane diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, and methyl-2-methyl-1,5-pentamethylene diisocyanate; aliphatic diisocyanates containing an alicyclic structure such as methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 1,2-bis(isocyanatemethyl)cyclohexane, 1,3-bis(isocyanatemethyl)cyclohexane, isophorone diisocyanate, and norbornane diisocyanate; and diisocyanates containing an aromatic ring such as m-phenylene diisocyanate, p-phenylene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, naphthylene-1,4-diisocyanate, and naphthylene-1,5-diisocyanate. These diisocyanates can be used alone or in combination.

[0037] When Y in the general formula (B2-3) does not contain an aromatic ring, the diisocyanate is a diisocyanate containing an aromatic ring. When Y in the general formula (B2-3) contains an aromatic ring, from the viewpoint of improving the elongation percentage of the cured product, the diisocyanate is preferably at least one selected from the group consisting of chain aliphatic diisocyanates and aliphatic diisocyanates containing an alicyclic structure, more preferably at least one selected from the group consisting of hexamethylene diisocyanate, 1,2-bis(isocyanatemethyl)cyclohexane, 1,3-bis(isocyanatemethyl)cyclohexane, and isophorone diisocyanate, and even more preferably hexamethylene diisocyanate.

[0038] In the general formula (B2-3), Y is a divalent group and is a residue of a diol represented by HO-Y-OH. Examples of such diols include linear aliphatic diols such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol; diols containing an alicyclic structure such as cyclohexanedimethanol and tricyclodecanedimethanol; and diols containing an aromatic ring such as biphenol, bisphenol A, bisphenol F, and bisphenoxyfluoreneethanol, as well as diols obtained by adding ethylene oxide, propylene oxide, or caprolactone to these diols. These diols may be used alone or in combination.

[0039] From the viewpoint of improving the Tg, elongation, tensile stress, and tensile modulus of the cured product, the diol is preferably at least one selected from the group consisting of chain aliphatic diols and diols containing an aromatic ring, more preferably a diol containing an aromatic ring, and even more preferably at least one selected from the group consisting of bisphenol A, bisphenol F, and diols obtained by adding ethylene oxide or propylene oxide to these.

[0040] Y in the general formula (B2-3) is more preferably a divalent group represented by the following general formula (Y1). In the formula, R ６ and R ７ each independently represents a hydrogen atom or a methyl group, preferably a methyl group. p and q represent the number of repeating units, each independently representing a number from 0 to 20. * represents a bond.

[0041] In the general formula (B2-3), r is a number of 1 or more, and preferably a number of 1 or more and 200 or less.

[0042] Furthermore, examples of commercially available polyfunctional (meth)acrylates having a structure derived from aromatic hydrocarbon formaldehyde resins, which are used as component (B2), include "NIKANOL XUAT" (urethane acrylate xylene resin) manufactured by Fudow Co., Ltd.

[0043] The content of component (B2) in component (B) is preferably 30 to 99% by mass, more preferably 30 to 95% by mass, even more preferably 30 to 90% by mass, still more preferably 30 to 85% by mass, even more preferably 40 to 85% by mass, even more preferably 50 to 85% by mass, even more preferably 65 to 85% by mass, even more preferably 75 to 85% by mass, and even more preferably 80 to 85% by mass. If the content of component (B2) in component (B) is 30% by mass or more, it is likely to contribute to improvements in the Tg, tensile stress, and tensile modulus of the cured product, while if it is 99% by mass or less, the elongation of the cured product can be maintained.

[0044] In addition to components (B1) and (B2), component (B) may also contain a monofunctional (meth)acrylate and a polyfunctional (meth)acrylate other than components (B1) and (B2) for the purpose of lowering the viscosity of the composition, etc. However, from the viewpoint of improving the Tg, elongation, tensile stress, and tensile modulus of the cured product, the total content of components (B1) and (B2) in component (B) is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and still more preferably 95% by mass or more, but 100% by mass or less.

[0045] <Component (C): Compound Having a (Meth)acryloyloxy Group and a Glycidyl Group> Component (C) used in the present invention is a compound having a (meth)acryloyloxy group and a glycidyl group. Component (C) is not particularly limited as long as it is a compound having at least one (meth)acryloyloxy group and at least one glycidyl group. However, from the viewpoint of improving the Tg, elongation, tensile stress, and tensile modulus of the cured product, component (C) is preferably a compound having 1 to 3 (meth)acryloyloxy groups and 1 to 3 glycidyl groups, more preferably a compound having 1 to 2 (meth)acryloyloxy groups and 1 to 2 glycidyl groups, and even more preferably a compound having one (meth)acryloyloxy group and one glycidyl group.

[0046] Component (C) is preferably a low molecular weight compound from the viewpoint of acting as a crosslinking agent to improve the Tg, tensile stress, and tensile modulus of the cured product, and specifically, is a compound having a molecular weight of 1,000 or less, preferably 800 or less, and more preferably 600 or less. Furthermore, from the viewpoint of having a (meth)acryloyloxy group and a glycidyl group, the molecular weight is preferably 140 or more.

[0047] Component (C) more preferably contains a compound represented by the following general formula (1): In formula (1), R １１ represents a hydrogen atom or a methyl group. Z represents a single bond, -(CH ２ ) ｍ -O- (where m is a number from 2 to 8), or a divalent group represented by the following general formula (2): In formula (2), R １２ and R １３ each independently represents a hydrogen atom or a methyl group, and n is a number from 1 to 5. * represents a bond.

[0048] In formula (1), R １１ is preferably a methyl group. Z is preferably a single bond or a divalent group represented by the general formula (2). In formula (2), R １２ and R １３ is preferably a methyl group, and n is preferably 1 to 3, more preferably 1 to 2, and even more preferably 1.

[0049] Specific examples of the compound represented by general formula (1) include at least one selected from the group consisting of glycidyl (meth)acrylate, a compound represented by the following general formula (C-1), and a compound represented by the following general formula (C-2): Of these, from the viewpoint of improving the Tg, elongation, tensile stress, and tensile modulus of the cured product, component (C) preferably contains at least one selected from the group consisting of glycidyl (meth)acrylate and a compound represented by the following general formula (C-2), and more preferably contains at least one selected from the group consisting of glycidyl methacrylate and a compound represented by the following general formula (C-2): In the formula, R １１ represents a hydrogen atom or a methyl group.

[0050] The compound represented by the general formula (C-2) is a compound also known as bisphenol A half epoxy (meth)acrylate, and examples of commercially available products thereof include "BAEM-50" (active ingredient amount: 50% by mass) manufactured by KSM Corporation.

[0051] <Component (D): Epoxy Resin Curing Agent Containing Boron Amine Complex> Component (D) used in the present invention contains a boron amine complex from the viewpoint of improving the pot life of the composition. From the viewpoint of improving the pot life of the composition, the content of the boron amine complex in component (D) is preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 70% by mass or more, still more preferably 80% by mass or more, and still more preferably 90% by mass or more, but 100% by mass or less.

[0052] Examples of the boron amine complex include boron halide amine complexes, such as boron trifluoride amine complexes and boron trichloride amine complexes, and from the viewpoint of improving the pot life of the composition, preferably contains boron trichloride amine complexes.

[0053] Examples of the amine component in the boron amine complex include alkylamines, alkanolamines, and cyclic aliphatic amines. Examples of alkylamines include monoalkylamines such as monoethylamine, monopropylamine, monobutylamine, monohexylamine, monooctylamine, and monolaurylamine; dialkylamines such as dimethylamine, diethylamine, dipropylamine, dibutylamine, dihexylamine, dioctylamine, and dilaurylamine; and trialkylamines such as triethylamine, tripropylamine, tributylamine, trihexylamine, trioctylamine, trilaurylamine, N,N-dimethylethylamine, N,N-dimethylpropylamine, N,N-dimethylbutylamine, N,N-dimethylhexylamine, N,N-dimethyloctylamine, and N,N-dimethyllaurylamine. Examples of alkanolamines include monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, N-methylethanolamine, N-methylisopropanolamine, N-butylethanolamine, N-methyldiethanolamine, N-butyldiethanolamine, N-methyldiisopropanolamine, etc. Examples of cyclic aliphatic amines include piperidine, N,N-dicyclohexylmethylamine, etc.

[0054] Among the above, from the viewpoint of improving the pot life of the composition, the amine component in the boron amine complex is preferably a trialkylamine, more preferably contains at least one selected from the group consisting of N,N-dimethylethylamine, N,N-dimethylpropylamine, N,N-dimethylbutylamine, N,N-dimethylhexylamine, N,N-dimethyloctylamine, and N,N-dimethyllaurylamine, and further preferably contains N,N-dimethyloctylamine.

[0055] Commercially available boron amine complexes used as component (D) include "Accelerator DY 9577" (boron trichloride amine complex, amine component: N,N-dimethyl-n-octylamine) manufactured by HUNTSMAN.

[0056] Component (D) may also contain an epoxy resin curing agent other than a boron amine complex. Examples of epoxy resin curing agents other than a boron amine complex include amine-based curing agents, phenol-based curing agents, acid anhydride-based curing agents, and hydrazide-based curing agents, and one or more of these may be used. However, from the viewpoint of improving the pot life of the composition, the content of the epoxy resin curing agent other than a boron amine complex in component (D) is preferably 70% by mass or less, more preferably 50% by mass or less, even more preferably 30% by mass or less, still more preferably 20% by mass or less, still more preferably 10% by mass or less, and even more preferably 5% by mass or less, with the lower limit being 0% by mass.

[0057] <Component (E): Thermal Radical Polymerization Initiator> The component (E) used in the present invention may be any compound that generates radicals upon heating and is capable of polymerizing the (meth)acryloyloxy groups in the components (B) and (C), and examples thereof include azo compounds and organic peroxides.

[0058] Examples of the azo compound include azobisisobutyronitrile (AIBN), 2,2'-azobis(2,4-dimethylvaleronitrile) (ABVN), 4,4'-azobis(4-cyanopentanoic acid) (ABCVA), 2,2'-azobis(2-methylbutyronitrile) (AMBN), 2,2'-azobis(2-methylpropionamidine) dihydrochloride (AAPH), 2,2'-azobis(2-methylpropionate) dimethyl, 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, and the like, and one or more of these may be used.

[0059] Examples of organic peroxides include peroxyketals such as 2,2-bis(4,4-di-tert-butylperoxycyclohexyl)propane, 1,1-di(tert-hexylperoxy)cyclohexane, 1,1-di(tert-butylperoxy)cyclohexane, n-butyl-4,4-di(tert-butylperoxy)valerate, and 2,2-di(tert-butylperoxy)butane; hydroperoxides such as tert-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, and 1,1,3,3-tetramethylbutyl hydroperoxide; tert-butylcumyl peroxide, di-tert-butyl peroxide, di-tert-hexyl peroxide, dicumyl peroxide, α, Dialkyl peroxides such as α'-di(tert-butylperoxy)diisopropylbenzene, tert-butylcumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexyne-3; diacyl peroxides such as diisobutyl peroxide, di(3,5,5-trimethylhexanol) peroxide, dilauroyl peroxide, disuccinic acid peroxide, and benzoyl peroxide; peroxydicarbonates such as diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, bis(4-tert-butylcyclohexyl)peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, and di-sec-butyl peroxydicarbonate;Cumyl peroxyneodecanoate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, tert-hexyl peroxyneodecanoate, tert-butyl peroxyneodecanoate, tert-hexyl peroxypivalate, tert-butyl peroxypivalate, 2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, tert-hexyl peroxy-2-ethylhexanoate, tert-butyl peroxy-2-ethylhexanoate, tert- Examples of peroxyesters include butyl peroxylaurate, tert-butylperoxy-3,5,5-trimethylhexanoate, tert-hexylperoxyisopropyl monocarbonate, tert-butylperoxyisopropyl monocarbonate, tert-butylperoxy-2-ethylhexyl monocarbonate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, tert-butyl peroxyacetate, tert-hexyl peroxybenzoate, and tert-butyl peroxybenzoate, and one or more of these can be used;

[0060] Among the above, from the viewpoint of improving the pot life of the composition, component (E) is preferably a thermal radical polymerization initiator having a 10-hour half-life temperature of 100° C. or higher, and more preferably an organic peroxide having a 10-hour half-life temperature of 100° C. or higher. Examples of organic peroxides having a 10-hour half-life temperature of 100° C. or higher include at least one selected from the group consisting of peroxyketals, hydroperoxides, dialkyl peroxides, and peroxyesters.

[0061] From the viewpoint of the curability of components (B) and (C) and improving the pot life of the composition, component (E) preferably contains a dialkyl peroxide, and more preferably contains 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane.

[0062] <Content> The content of component (A) in the thermosetting resin composition is preferably 30 to 85% by mass, more preferably 40 to 85% by mass, even more preferably 50 to 80% by mass, and still more preferably 60 to 80% by mass, from the viewpoint of improving the pot life of the composition and the Tg, elongation, tensile stress, and tensile modulus of the cured product.

[0063] The content of component (B) in the thermosetting resin composition is preferably 5 to 60% by mass, more preferably 10 to 50% by mass, even more preferably 15 to 40% by mass, and still more preferably 15 to 30% by mass, from the viewpoint of improving the pot life of the composition and the Tg, elongation, tensile stress, and tensile modulus of the cured product.

[0064] The content of component (B) in the thermosetting resin composition is preferably 5 to 70 parts by mass, more preferably 10 to 60 parts by mass, even more preferably 10 to 50 parts by mass, even more preferably 15 to 50 parts by mass, even more preferably 20 to 50 parts by mass, and even more preferably 30 to 50 parts by mass, per 100 parts by mass of component (A). When the content of component (B) in the thermosetting resin composition is 5 parts by mass or more per 100 parts by mass of component (A), a long pot life is easily achieved. When the content is 70 parts by mass or less, the Tg, tensile stress, and tensile modulus of the cured product are easily maintained.

[0065] The content of component (C) in the thermosetting resin composition is preferably 0.1 to 20% by mass, more preferably 0.3 to 10% by mass, even more preferably 0.5 to 7.0% by mass, and still more preferably 0.8 to 5.0% by mass, from the viewpoint of improving the pot life of the composition and improving the Tg, elongation, tensile stress, and tensile modulus of the cured product.

[0066] The content of component (C) in the thermosetting resin composition is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, even more preferably 0.5 to 10 parts by mass, and even more preferably 0.8 to 6.0 parts by mass, per 100 parts by mass of the total of components (A) and (B). When the content of component (C) in the thermosetting resin composition is 0.1 part by mass or more, per 100 parts by mass of the total of components (A) and (B), it tends to contribute to improving the Tg, tensile stress, and tensile modulus of the cured product, while when it is 30 parts by mass or less, the elongation of the cured product can be maintained.

[0067] The content of component (D) in the thermosetting resin composition is preferably 0.1 to 40 parts by mass, more preferably 0.5 to 20 parts by mass, even more preferably 1 to 10 parts by mass, still more preferably 2 to 10 parts by mass, and even more preferably 3 to 8 parts by mass, per 100 parts by mass of component (A). If the content of component (D) in the thermosetting resin composition is 0.1 part by mass or more per 100 parts by mass of component (A), curability is easily ensured, and if it is 40 parts by mass or less, a long pot life is easily achieved.

[0068] The content of component (E) in the thermosetting resin composition is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 4 parts by mass, even more preferably 0.1 to 3 parts by mass, and even more preferably 0.5 to 2 parts by mass, per 100 parts by mass of component (B). If the content of component (E) in the thermosetting resin composition is 0.01 part by mass or more per 100 parts by mass of component (B), curability is easily ensured, and if it is 5 parts by mass or less, a long pot life is easily achieved.

[0069] From the viewpoint of effectively exhibiting the effects of the present invention, the total content of components (A) to (E) in the thermosetting resin composition is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and still more preferably 95% by mass or more, but 100% by mass or less, of the solid content of the thermosetting resin composition. Note that the "solid content of the thermosetting resin composition" refers to the amount obtained by excluding water and organic solvents from the total amount of the thermosetting resin composition.

[0070] <Other Components> The thermosetting resin composition may further contain other components, such as a modifying component such as a filler or a plasticizer, a flow-adjusting component such as a thixotropic agent, a reactive or non-reactive diluent, a pigment, a leveling agent, a tackifier, or a stress relaxation component, depending on the application.

[0071] Among the above, examples of the stress relaxation component include elastomer particles such as silicone-based elastomer particles, butyl acrylate-based elastomer particles, polyetheramine-based elastomer particles, and other rubber particles. Liquid rubber components such as epoxidized polybutadiene can also be used. Commercially available stress relaxation components include Kane Ace B series, FM series, M series, and MX series manufactured by Kaneka Corporation, and liquid epoxidized polybutadienes such as Epolead PB3600 and Epolead PB4700 manufactured by Daicel Corporation. When the thermosetting resin composition contains a stress relaxation component, the content thereof is preferably 0.1 to 15% by mass, more preferably 0.5 to 10% by mass, of the solid content of the thermosetting resin composition.

[0072] <Solvent> The thermosetting resin composition of the present invention may further contain a solvent from the viewpoint of improving impregnation into reinforcing fibers. Examples of the solvent include alcohol-based solvents such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methoxyethanol, 2-ethoxyethanol, 2-propoxyethanol, 2-butoxyethanol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, and 1-propoxy-2-propanol; ester-based solvents such as ethyl acetate and butyl acetate; ketone-based solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; ether-based solvents such as diethyl ether and diisopropyl ether; and hydrocarbon-based solvents such as toluene. One or more of these may be used. From the viewpoint of the solubility of the blended components and the ease of removing the solvent, the solvent is preferably at least one selected from the group consisting of alcohol-based solvents, ester-based solvents, ketone-based solvents, and hydrocarbon-based solvents having 8 or less carbon atoms, and more preferably at least one selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, and toluene.

[0073] When the thermosetting resin composition contains a solvent, its content is not particularly limited, but from the viewpoint of improving the impregnation of the reinforcing fibers, it is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more in the thermosetting resin composition. From the viewpoint of ease of solvent removal, it is preferably 80% by mass or less, more preferably 70% by mass or less. The thermosetting resin composition may be a solvent-free composition that does not substantially contain a solvent. A solvent-free thermosetting resin composition is a thermosetting resin composition in which the solvent content in the thermosetting resin composition is preferably less than 5% by mass, more preferably 2% by mass or less, even more preferably 1% by mass or less, even more preferably 0.5% by mass or less, and even more preferably 0% by mass. The thermosetting resin composition of the present invention is preferably a non-aqueous thermosetting resin composition, and it is preferable that the water content is low. The water content in the thermosetting resin composition is preferably less than 10% by mass, more preferably less than 5% by mass, even more preferably less than 2% by mass, still more preferably less than 1% by mass, still more preferably less than 0.1% by mass, and still more preferably 0% by mass. The water content here refers to the amount of water intentionally added to the thermosetting resin composition, and does not exclude the presence of a small amount of water as an impurity.

[0074] <Pot Life> The thermosetting resin composition of the present invention has a long pot life, and can achieve a pot life of, for example, 180 days or more when stored at room temperature (23°C).

[0075] There are no particular limitations on the method for preparing the thermosetting resin composition, and the composition can be prepared by mixing components (A) to (E) and other components used as needed using known methods and equipment. There are also no particular limitations on the order in which the components contained in the thermosetting resin composition are mixed. However, if any of the resin components (A) to (C) has a high viscosity, it is preferable to first heat and mix components (A) to (C) to 80 to 120°C, then cool to below 80°C, and then mix components (D) and (E). This is to prevent thermal curing from progressing during the preparation of the thermosetting resin composition.

[0076] [Cured Product] The cured product of the thermosetting resin composition of the present invention (hereinafter simply referred to as the "cured product of the present invention") is obtained by thermally curing the above-described thermosetting resin composition of the present invention using a known method. The curing conditions for the thermosetting resin composition are appropriately selected depending on the application and form. The curing temperature is preferably 80 to 180°C, more preferably 100 to 160°C, and the curing time is preferably 1 minute to 12 hours, more preferably 5 minutes to 6 hours. The form of the cured product of the present invention is also not particularly limited and can be selected depending on the application. For example, when the thermosetting resin composition is used as a paint, the cured product of the composition is usually in the form of a film. From the viewpoint of effectively exerting the effects of the present invention, the cured product of the present invention is preferably a matrix resin for a fiber-reinforced composite material, as described below.

[0077] From the viewpoint of use as a matrix resin for a fiber-reinforced composite material described below, the glass transition temperature (Tg) of the cured product of the present invention is preferably 100° C. or higher, more preferably 110° C. or higher, even more preferably 115° C. or higher, and still more preferably 120° C. or higher, and is usually 200° C. or lower. Specifically, the Tg of the cured product can be measured by the method described in the Examples.

[0078] The tensile elongation of the cured product of the present invention is preferably 4.0% or more, more preferably 4.5% or more, and even more preferably 5.0% or more from the viewpoint of improving impact resistance when used as a matrix resin for a fiber-reinforced composite material, etc., as described below, and is preferably 20% or less, more preferably 10% or less from the viewpoint of obtaining high hardness. The tensile stress of the cured product of the present invention is preferably 40 MPa or more, more preferably 43 MPa or more, and even more preferably 45 MPa or more from the viewpoint of improving hardness when used as a matrix resin for a fiber-reinforced composite material, etc., as described below. The tensile modulus of the cured product of the present invention is preferably 1.2 GPa or more, more preferably 1.3 GPa or more, and even more preferably 1.5 GPa or more from the viewpoint of improving hardness when used as a matrix resin for a fiber-reinforced composite material, etc., as described below. The tensile elongation, tensile stress, and tensile modulus of the cured product can be measured in accordance with JIS K7161-1:2014 and JIS K7161-2:2014, specifically by the methods described in the Examples.

[0079] [Prepreg] The prepreg of the present invention contains the thermosetting resin composition and reinforcing fibers. Examples of the reinforcing fibers used in the prepreg include short fibers, long fibers, and continuous fibers. Among these, from the viewpoint of producing large structures using the resulting prepreg, long fibers or continuous fibers are preferred, and continuous fibers are more preferred. In this specification, short fibers refer to fibers having a fiber length of 0.1 mm or more but less than 10 mm, and long fibers refer to fibers having a fiber length of 10 mm or more but 100 mm or less. Furthermore, continuous fibers refer to fiber bundles having a fiber length of more than 100 mm.

[0080] Examples of the shape of the continuous fiber include tow, sheet, tape, etc., and examples of the continuous fiber constituting the sheet or tape include unidirectional (UD) materials, woven fabrics, nonwoven fabrics, etc. From the viewpoint of producing a fiber-reinforced composite material using a prepreg by a filament winding method or a tape winding method, the shape of the continuous fiber is preferably tow or tape, and more preferably tow. The number of continuous fiber bundles (number of filaments) constituting the tow is preferably 3K to 50K, more preferably 6K to 40K, from the viewpoint of easily obtaining high strength and high elastic modulus.

[0081] In the case of continuous fibers, the average fiber length of the continuous fiber bundle is not particularly limited, but from the viewpoint of molding processability, it is preferably 1 to 10,000 m, more preferably 100 to 10,000 m. From the viewpoint of molding processability and the viewpoint that high strength and high elastic modulus can be easily obtained, the average fineness of the continuous fiber bundle is preferably 50 to 2,000 tex (g / 1,000 m), more preferably 200 to 1,500 tex, and even more preferably 500 to 1,500 tex. The average tensile elastic modulus of the continuous fiber bundle is preferably 50 to 1,000 GPa.

[0082] Examples of materials for the reinforcing fibers include inorganic fibers such as carbon fiber, glass fiber, basalt fiber, metal fiber, boron fiber, and ceramic fiber; and organic fibers such as aramid fiber, polyoxymethylene fiber, aromatic polyamide fiber, polyparaphenylene benzobisoxazole fiber, and ultra-high molecular weight polyethylene fiber. Among these, inorganic fibers are preferred from the viewpoint of achieving high strength. Because they are lightweight, have high strength, and have a high elastic modulus, at least one fiber selected from the group consisting of carbon fiber, glass fiber, and basalt fiber is preferred. From the viewpoint of strength and light weight, carbon fiber is more preferred. Examples of carbon fibers include polyacrylonitrile-based carbon fiber and pitch-based carbon fiber. Carbon fibers derived from plant-derived materials such as lignin and cellulose can also be used.

[0083] The reinforcing fibers may be treated with a treatment agent. Examples of the treatment agent include a surface treatment agent and a sizing agent. The surface treatment agent is preferably a silane coupling agent. Examples include a silane coupling agent having a vinyl group, a silane coupling agent having an amino group, a silane coupling agent having an epoxy group, a silane coupling agent having a (meth)acrylic group, and a silane coupling agent having a mercapto group.

[0084] Examples of the sizing agent include urethane-based sizing agents, epoxy-based sizing agents, acrylic-based sizing agents, polyester-based sizing agents, vinyl ester-based sizing agents, polyolefin-based sizing agents, polyether-based sizing agents, and carboxylic acid-based sizing agents, and these can be used alone or in combination of two or more. Examples of sizing agents that combine two or more types include urethane / epoxy-based sizing agents, urethane / acrylic-based sizing agents, and urethane / carboxylic acid-based sizing agents.

[0085] The amount of the treatment agent is preferably 0.001 to 5% by mass, more preferably 0.1 to 3% by mass, and even more preferably 0.5 to 2% by mass relative to the reinforcing fiber, from the viewpoint of improving the interfacial adhesion between the thermosetting resin composition and the cured product and further improving the strength and impact resistance of the resulting prepreg and fiber-reinforced composite material.

[0086] Commercially available products can also be used as reinforcing fibers. Commercially available continuous carbon fibers (tows) include, for example, the Torayca yarns "T300", "T300B", "T400HB", "T700SC", "T800SC", "T800HB", "T830HB", "T1000GB", "T100GC", "M35JB", "M40JB", "M46JB", "M50JB", "M55J", "M55JB", "M60JB", "M30SC", and "Z600" series manufactured by Toray Industries, Inc.; and Tenax "HTA40" series, "HTS40" series, "HTS45" series, and "HTS45P12" manufactured by Teijin Limited. series, "STS40" series, "UTS50" series, "ITS50" series, "ITS55" series, "IMS40" series, "IMS60" series, "IMS65" series, "IMS65P12" series, "HMA35" series, "UMS40" series, "UMS45" series, "UMS55" series, and "HTS40MC" series; carbon fiber tows of PYROFIL "HT", "IM", and "HM" series, GRAFIL "HT" series, and "DIALEAD" series manufactured by Mitsubishi Chemical Corporation; and the like.Commercially available continuous carbon fibers other than tow include Toray Industries, Inc.'s Torayca cloths "CO6142," "CO6151B," "CO6343," "CO6343B," "CO6347B," "CO6644B," "CK6244C," "CK6273C," "CK6261C," "UT70" series, "UM46" series, "BT70" series, "T300" series, "T300B" series, "T400HB" series, "T700SC" series, "T800SC" series, "T800HB" series, "T1000GB" series, "M35JB" series, and "M40 JB series, M46JB series, M50JB series, M55J series, M55JB series, M60JB series, M30SC series, and Z600GT series; carbon fiber fabrics such as PYROFIL "TR3110M", "TR3523M", "TR3524M", "TR6110HM", "TR6120HM", "TRK101M", "TRK510M", "TR3160TMS", "TRK979PQRW", "TRK976PQRW", "TR6185HM", and "TRK180M" manufactured by Mitsubishi Chemical Corporation; and the like.

[0087] The content of the reinforcing fibers in the prepreg is preferably in a range such that the volume fraction of the reinforcing fibers in the prepreg is 0.10 or more, more preferably 0.20 or more, even more preferably 0.30 or more, and even more preferably 0.40 or more, from the viewpoint of obtaining high strength and high elastic modulus. Also, from the viewpoint of improving impact resistance and moldability, the volume fraction of the reinforcing fibers in the prepreg is preferably 0.85 or less, more preferably 0.80 or less, and even more preferably 0.70 or less. １ can be calculated from the following formula: １ = {mass (g) of reinforcing fiber / specific gravity of reinforcing fiber} ÷ [{mass (g) of reinforcing fiber / specific gravity of reinforcing fiber} + {mass (g) of solid content of impregnated thermosetting resin composition / specific gravity of solid content of thermosetting resin composition}]

[0088] Furthermore, from the viewpoint of obtaining the effects of the present invention, the total content of the solids of the thermosetting resin composition constituting the prepreg and the reinforcing fibers is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, but 100% by mass or less.

[0089] <Prepreg Shape and Manufacturing Method> The shape of the prepreg varies depending on the shape of the reinforcing fibers used. However, from the viewpoint of manufacturing a fiber-reinforced composite material by a filament winding method or a tape winding method, the prepreg of the present invention is preferably a tow prepreg or a tape prepreg. Examples of tape prepregs include UD tape prepregs using unidirectional (UD) materials. The prepreg of the present invention may also be a sheet-shaped prepreg using continuous fibers in the form of UD materials, woven fabrics, nonwoven fabrics, etc.

[0090] The method for producing the prepreg is not particularly limited, and the prepreg can be produced according to a conventional method. For example, the prepreg can be obtained by impregnating the reinforcing fibers with the thermosetting resin composition, and then optionally subjecting the resultant to a drying step to remove the solvent.

[0091] The method for impregnating the reinforcing fibers with the thermosetting resin composition is not particularly limited, and any known method can be used as appropriate depending on the shape of the reinforcing fibers, etc. For example, when producing a tow prepreg, a method can be used in which a continuous fiber bundle unwound from a roll is immersed in a resin bath filled with the above-mentioned thermosetting resin composition, and after impregnation with the composition, the bundle is pulled out of the resin bath. A step of removing excess thermosetting resin composition using a squeeze roll or the like can then be performed. The impregnation with the thermosetting resin composition can also be performed under pressurized or reduced pressure as necessary.

[0092] Next, if necessary, the reinforcing fibers impregnated with the thermosetting resin composition are subjected to a drying process to remove the solvent. The drying conditions in the drying process are not particularly limited, but are preferably conditions that allow the solvent to be removed and do not cause excessive curing of the thermosetting resin composition. From this perspective, for example, the drying temperature can be selected in the range of 30 to 120 ° C, and the drying time can be selected in the range of 10 seconds to 5 minutes.

[0093] The prepreg obtained through the drying step may be wound up or the like to form a prepreg product, or it may be subjected to the drying step without being wound up or the like and then continuously supplied to the production of a fiber-reinforced composite material.

[0094] The prepreg of the present invention has a long pot life, and can achieve a pot life of, for example, 180 days or more when stored at room temperature (23° C.).

[0095] [Fiber-reinforced composite material] The fiber-reinforced composite material of the present invention (hereinafter also simply referred to as "composite material") is a cured product of the prepreg, and includes a cured product of the thermosetting resin composition and reinforcing fibers. By including a cured product of the thermosetting resin composition, the fiber-reinforced composite material of the present invention has high heat resistance and impact resistance due to the high glass transition temperature and elongation of the cured product. The prepreg, thermosetting resin composition, reinforcing fibers, and preferred embodiments thereof used in producing the composite material are the same as those described above.

[0096] <Content> From the viewpoint of obtaining high strength and high modulus of elasticity, the content of reinforcing fibers in the fiber reinforced composite is preferably in a range such that the volume fraction of the reinforcing fibers in the fiber reinforced composite is 0.10 or more, more preferably 0.20 or more, even more preferably 0.30 or more, and even more preferably 0.40 or more. From the viewpoint of improving impact resistance and moldability, the content is preferably 0.85 or less, more preferably 0.80 or less, and even more preferably 0.70 or less. The volume fraction Vf of the reinforcing fibers in the fiber reinforced composite can be calculated using the following formula: Vf = {mass (g) of reinforcing fibers / specific gravity of reinforcing fibers} ÷ [{mass (g) of reinforcing fibers / specific gravity of reinforcing fibers} + {mass (g) of cured product of thermosetting resin composition / specific gravity of cured product of thermosetting resin composition}]

[0097] <Method for Producing Fiber-Reinforced Composite Material> A composite material can be produced by pre-molding the prepreg into a desired shape and then curing the prepreg. For example, when the composite material of the present invention is applied to a hollow molded article such as a pipe, shaft, cylinder, or tank, a tow- or tape-shaped prepreg can be molded by a filament winding method, tape winding method, braiding method, 3D printer method, or the like to produce the composite material. In the filament winding method or tape winding method, specifically, a tow- or tape-shaped prepreg is wound around the outer surface of a balloon, mandrel, or liner, and then heat-cured to produce a composite material of a desired shape. In the braiding method, for example, a tow- or tape-shaped prepreg is braided with a braider using a balloon or mandrel to form a unidirectional or braided structure, and then the prepreg is heat-cured. Note that the braiding method can also be used to braid and mold a tow- or tape-shaped prepreg without using a balloon or mandrel.

[0098] When using a sheet-shaped prepreg using unidirectional (UD) material, woven fabric, nonwoven fabric, or the like as continuous fibers, a composite material can be produced by placing one or more prepregs in a mold and heating and curing them under vacuum or pressurized conditions.

[0099] The method for curing the prepreg in the production of the composite material is not particularly limited, and is carried out by a known method at a temperature and for a time sufficient to cure the thermosetting resin composition contained in the prepreg. The prepreg curing conditions depend on the thickness of the prepreg and the composite material to be formed, but for example, the curing temperature is preferably in the range of 80 to 180°C, more preferably 100 to 160°C, and the curing time is preferably selected in the range of 1 minute to 12 hours, more preferably 5 minutes to 6 hours.

[0100] From the viewpoint of production using a tow- or tape-shaped prepreg, the composite material of the present invention is suitably used for moldings having a hollow shape such as pipes, shafts, cylinders, tanks, etc. The composite material is suitable as a material for forming, for example, high-pressure gas containers.

[0101] [High-Pressure Gas Container] The high-pressure gas container of the present invention contains the fiber-reinforced composite material. It is sufficient that at least a portion of the high-pressure gas container of the present invention is made of the fiber-reinforced composite material. For example, in the case of a high-pressure gas container having a liner and an outer layer provided so as to cover the outer surface of the liner, at least one of the liner and the outer layer may be made of the fiber-reinforced composite material. Furthermore, in the case of a linerless high-pressure gas container, the entire container may be made of the fiber-reinforced composite material.

[0102] Specific embodiments of high-pressure gas containers containing a fiber-reinforced composite material include (1) a configuration having a metal liner and an outer layer made of the fiber-reinforced composite material of the present invention, (2) a configuration having a resin liner and an outer layer made of the fiber-reinforced composite material of the present invention, (3) a configuration having a liner made of the fiber-reinforced composite material of the present invention and an outer layer made of a material other than the fiber-reinforced composite material, and (4) a configuration consisting only of a container made of the fiber-reinforced composite material of the present invention (linerless).

[0103] Examples of the metal used for the "metallic liner" in (1) above include light alloys such as aluminum alloys and magnesium alloys.

[0104] The resin used for the "resin liner" in (2) above is not particularly limited as long as it has excellent gas barrier properties and pressure resistance, and examples thereof include thermoplastic resins, cured products of thermosetting resins, and cured products of photocurable resins. Among these, thermoplastic resins are preferred from the viewpoint of ease of molding the liner. Examples of such thermoplastic resins include polyamide resins, polyester resins, polyolefin resins, polyimide resins, polycarbonate resins, polyetherimide resins, polyamideimide resins, polyphenylene etherimide resins, polyphenylene sulfide resins, polysulfone resins, polyethersulfone resins, polyarylate resins, liquid crystal polymers, polyetheretherketone resins, polyetherketone resins, polyetherketoneketone resins, polyetheretherketoneketone resins, and polybenzimidazole resins. One or more of these resins may be used in combination. From the viewpoint of gas barrier properties and pressure resistance, the thermoplastic resin is preferably at least one resin selected from the group consisting of polyamide resins and polyolefin resins, and more preferably polyamide resins. In addition, from the viewpoint of improving impact resistance, the resin liner may contain the above-mentioned stress relaxation component.

[0105] The "outer layer made of a material other than the fiber-reinforced composite material" in (3) above is preferably an outer layer made of a fiber-reinforced composite material other than the fiber-reinforced composite material of the present invention, from the viewpoint of improving reinforcement.

[0106] In the above embodiments (1) to (3), the outer layer can be formed so as to cover the outer surface of the main body of the liner without any gaps. The outer layer may be provided directly on the outer surface of the liner. Alternatively, one or more other layers may be provided on the outer surface of the liner, and the outer layer may be provided on the surface of the other layers. For example, an adhesive layer may be provided between the liner and the outer layer to improve adhesion between the liner and the outer layer.

[0107] When the high-pressure gas container is of the above embodiment (1) or (2), the thickness of the outer layer made of the fiber-reinforced composite material of the present invention can be appropriately selected depending on the capacity, shape, etc. of the high-pressure gas container. From the viewpoint of imparting high gas barrier properties and impact resistance, the thickness is preferably 100 μm or more, more preferably 200 μm or more, and even more preferably 400 μm or more, and from the viewpoint of reducing the size and weight of the high-pressure gas container, the thickness is preferably 80 mm or less, more preferably 60 mm or less.

[0108] When the high-pressure gas container is of the above embodiment (3), the thickness of the liner made of the fiber-reinforced composite material of the present invention can be appropriately selected depending on the capacity, shape, etc. of the high-pressure gas container. From the viewpoints of gas barrier properties and pressure resistance, the thickness is preferably 100 μm or more, more preferably 200 μm or more, and even more preferably 400 μm or more, and from the viewpoints of miniaturization and weight reduction of the high-pressure gas container, the thickness is preferably 60 mm or less, more preferably 40 mm or less.

[0109] When the high-pressure gas container is of the above embodiment (4), the thickness of the container made of the fiber-reinforced composite material of the present invention can be appropriately selected depending on the capacity, shape, etc. of the high-pressure gas container. From the viewpoint of gas barrier properties and pressure resistance, the thickness is preferably 1 mm or more, more preferably 2 mm or more, and even more preferably 5 mm or more, and from the viewpoint of miniaturization and weight reduction of the high-pressure gas container, the thickness is preferably 80 mm or less, more preferably 60 mm or less.

[0110] The content of reinforcing fibers in a liner, outer layer, or high-pressure gas container made of the fiber-reinforced composite material of the present invention is preferably in a range such that the volume fraction of reinforcing fibers is 0.10 or more, more preferably 0.20 or more, even more preferably 0.30 or more, and even more preferably 0.40 or more, from the viewpoint of obtaining high strength and high elastic modulus. Furthermore, from the viewpoint of gas barrier properties, impact resistance, and moldability, the volume fraction is preferably 0.85 or less, more preferably 0.80 or less, even more preferably 0.75 or less, and even more preferably 0.70 or less. The volume fraction of reinforcing fibers can be calculated in the same manner as above.

[0111] Among the above, from the viewpoint of light weight and the requirement for high gas barrier properties for the fiber-reinforced composite material, the high-pressure gas container is preferably any one of the above-mentioned embodiments (2), (3) and (4), and embodiment (3) or (4) is more preferable.

[0112] The high-pressure gas container may further include components made of materials other than the fiber-reinforced composite material, such as a mouthpiece, a valve, etc. The surface of the high-pressure gas container may be formed with any layer, such as a protective layer, a paint layer, or a rust-preventing layer.

[0113] The gas to be stored in the high-pressure gas container may be any gas that is in a gaseous state at 25°C and 1 atm, and examples thereof include hydrogen, oxygen, carbon dioxide, nitrogen, argon, LPG, chlorofluorocarbon alternatives, methane, etc. Among these, hydrogen is preferred from the viewpoint of the effectiveness of the present invention.

[0114] <Method for Manufacturing High-Pressure Gas Container> As a method for manufacturing a high-pressure gas container of the present invention, the manufacturing methods described above for manufacturing fiber-reinforced composite materials can be used as appropriate, depending on the form of the reinforcing fiber or prepreg used. When manufacturing a high-pressure gas container using a tow- or tape-shaped prepreg, the tow- or tape-shaped prepreg can be formed by a filament winding method, a tape winding method, a braiding method, a 3D printer method, or the like, to manufacture the high-pressure gas container. When the high-pressure gas container is in the form (1) or (2) above, the tow- or tape-shaped prepreg can be wound using a filament winding method or a tape winding method so as to cover the outer surface of a metal or resin liner, and then heat-cured to form an outer layer made of a fiber-reinforced composite material, thereby manufacturing the high-pressure gas container. When the high-pressure gas container is in the form (3) or (4) above, the high-pressure gas container can be manufactured by forming the tow- or tape-shaped prepreg into a container shape by a filament winding method, a tape winding method, a braiding method, a 3D printer method, or the like, and then heat-curing the prepreg.

[0115] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. Measurements and evaluations in the examples were carried out by the following methods.

[0116] <Glass Transition Temperature (Tg)> The thermosetting resin composition prepared in each example was molded into a flat plate measuring 200 mm x 200 mm x 2 mm thick, and thermally cured in a hot air oven at 130°C for 180 minutes to produce a cured product. A strip measuring 50 mm x 10 mm x 2 mm thick was cut from the cured product to serve as a dynamic viscoelasticity (DMA) measurement sample. Using the sample, DMA bending measurement was performed under the following conditions using a rotational rheometer "ARES G2" (manufactured by TA Instruments). The peak top value of tan δ, plotted on the vertical axis and the measurement temperature on the horizontal axis, was taken as the Tg of the cured product. (Measurement Conditions) Measurement mode: bending DMA measurement Measurement temperature: 30 to 180°C Heating rate: 5°C / min

[0117] <Tensile Elongation, Tensile Stress, and Tensile Modulus of Elasticity> The thermosetting resin composition prepared in each example was molded into a 200 mm x 200 mm x 2 mm thick plate and thermally cured in a hot air oven at 130°C for 180 minutes to produce a cured product. A rectangular strip measuring 180 mm x 15 mm x 2 mm thick was cut from the cured product to serve as a tensile test specimen. Using the test specimen, a tensile test was performed under the following conditions (N = 3) in accordance with JIS K7161-1:2014 and JIS K7161-2:2014 using a precision universal testing machine ("Autograph AGX-plus" manufactured by Shimadzu Corporation). The tensile elongation, tensile stress, and tensile modulus of elasticity were calculated using the following formula. The length of the test specimen at break was calculated from the displacement of the load cell at break. (Measurement conditions) Distance between grips: 115 mm Distance between gauge lines: 75 mm Load cell (tensile force): 1 kN Tensile speed: 1 mm / min (tensile direction: longitudinal direction of test piece) (Calculation formula) Tensile elongation (%) = (length of test piece at break - initial length of test piece) / (initial length of test piece) × 100 Tensile stress (MPa) = load (N) at break of test piece / initial cross-sectional area of ​​test piece (mm ２ ) Tensile modulus (GPa) = Elastic modulus gradient (N / mm) × Initial test piece length (mm) / Initial test piece cross-sectional area (mm２ ) x 10 －３ The elastic modulus gradient here means the slope of the stress-strain curve corresponding to the two points where the tensile strain (the value obtained by dividing the increase in the gauge length by the gauge length) is 0.05% and 0.25%.

[0118] <Pot life> After measuring the initial viscosity at 23°C of the thermosetting resin composition prepared in each example, 10 g of the thermosetting resin composition was placed in a plastic cup (diameter 46 mm) and stored at 23°C. The time until the viscosity of the thermosetting resin composition became at least twice the initial viscosity was measured and is shown in the table. The viscosity of the thermosetting resin composition was measured using an E-type viscometer "TVE-22H cone-plate type viscometer" (manufactured by Toki Sangyo Co., Ltd.).

[0119] Examples 1 to 14 and Comparative Examples 1 to 5 (Preparation and Evaluation of Thermosetting Resin Compositions) The components shown in Table 1 were blended and mixed in the parts by mass shown in Table 1 to obtain thermosetting resin compositions. The obtained thermosetting resin compositions were evaluated by the methods described above. The results are shown in Table 1. The blend amounts (parts by mass) in Table 1 are all amounts of active ingredients.

[0120]

[0121] The components listed in Table 1 are as follows. <Polyfunctional epoxy resin (A)> Polyfunctional epoxy resin (liquid) having glycidyloxy groups derived from bisphenol A: "jER828" manufactured by Mitsubishi Chemical Corporation, liquid epoxy resin, epoxy equivalent: 186 g / equivalent, s = 0.11 in the structural formula below. Note that for a composition using bisphenol A half epoxy methacrylate ("BAEM-50" manufactured by KSM Corporation) described below as component (C), the "liquid polyfunctional epoxy resin (liquid) having glycidyloxy groups derived from bisphenol A" contains bisphenol A diglycidyl ether in an amount of "BAEM-50" (25% by mass) in addition to "jER828." Multifunctional epoxy resin (solid) having a glycidyloxy group derived from bisphenol A: "jER1004" manufactured by Mitsubishi Chemical Corporation, polymer type / solid epoxy resin, epoxy equivalent: 1026 g / equivalent, s=6.0 in the following structural formula

[0122] <(Meth)acrylate Compounds (B) Having No Glycidyl Group> (B1) Poly(butadiene-co-acrylonitrile) having methacryloyloxy groups at both ends, "Hypro1300X33LC" manufactured by Chori GLEX (B2-1) Ethoxylated bisphenol A dimethacrylate, k+l in the following structural formula = approximately 10, "BPE-500" manufactured by Shin-Nakamura Chemical Co., Ltd. (B2-1) Ethoxylated bisphenol A dimethacrylate, k+l in the following structural formula = approximately 17, "BPE-900" manufactured by Shin-Nakamura Chemical Co., Ltd. (B2-2) Bisphenol A epoxy dimethacrylate, a compound represented by the following structural formula, containing "BAEM-50" manufactured by KSM Co., Ltd. (25% by mass)

[0123] <Compound (C) Having a (Meth)acryloyloxy Group and a Glycidyl Group> Glycidyl methacrylate, manufactured by Mitsubishi Gas Chemical Co., Inc. Bisphenol A-type half epoxy methacrylate, a compound represented by the following structural formula, "BAEM-50" manufactured by KSM Corporation (content of bisphenol A-type half epoxy methacrylate: 50% by mass)

[0124] <Epoxy resin curing agent (D)> Boron trichloride amine complex (amine component: N,N-dimethyl-n-octylamine), "Accelerator DY 9577" manufactured by HUNTSMAN

[0125] <Thermal radical polymerization initiator (E)> 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, "Perhexa 25B" manufactured by NOF Corporation, 10-hour half-life temperature: 117.9°C

[0126] Table 1 shows that the cured products of the thermosetting resin compositions of the present invention achieved a glass transition temperature of 100°C or higher, a tensile elongation of 4% or higher, a tensile modulus of 1.2 GPa or higher, and a tensile stress of 40 MPa or higher. The thermosetting resin compositions also had a long pot life. In contrast, the cured products of the thermosetting resin compositions of Comparative Examples 1 to 5, which did not contain component (C), all had a tensile stress of less than 40 MPa, and in Comparative Examples 4 and 5, the tensile modulus was also below 1.2 GPa, failing to achieve excellent mechanical properties.

[0127] According to the present invention, a thermosetting resin composition can be provided which gives a cured product having a high glass transition temperature, elongation, tensile stress, and tensile modulus, and which has a long pot life; a cured product thereof; a prepreg containing the thermosetting resin composition; a fiber-reinforced composite material; and a high-pressure gas container.

Claims

1. A thermosetting resin composition comprising: component (A): a multifunctional epoxy resin; component (B): a (meth)acrylate compound having no glycidyl group; component (C): a compound having a (meth)acryloyloxy group and a glycidyl group; component (D): an epoxy resin curing agent containing a boron amine complex; and component (E): a thermal radical polymerization initiator.

2. The thermosetting resin composition according to claim 1, wherein said component (B) comprises component (B1): poly(butadiene-co-acrylonitrile) having (meth)acryloyloxy groups at both ends.

3. The thermosetting resin composition according to claim 1 or 2, wherein the component (B) comprises component (B2): a polyfunctional (meth)acrylate having an aromatic ring.

4. The thermosetting resin composition according to any one of claims 1 to 3, wherein the component (C) comprises a compound represented by the following general formula (1): In formula (1), R １１ represents a hydrogen atom or a methyl group. Z represents a single bond, -(CH ２ ) ｍ -O- (where m is a number from 2 to 8), or a divalent group represented by the following general formula (2). In formula (2), R １２ and R １３ each independently represents a hydrogen atom or a methyl group. n is a number from 1 to 5. * represents a bond.

5. The thermosetting resin composition according to any one of claims 1 to 4, wherein the amine component in the boron amine complex is a trialkylamine.

6. A cured product of the thermosetting resin composition according to any one of claims 1 to 5.

7. A prepreg comprising the thermosetting resin composition according to any one of claims 1 to 5 and reinforcing fibers.

8. The prepreg according to claim 7, wherein the reinforcing fibers are at least one type selected from the group consisting of carbon fibers, glass fibers, and basalt fibers.

9. The prepreg according to claim 7 or 8, wherein the prepreg is a tow prepreg or a tape prepreg.

10. A fiber-reinforced composite material which is a cured product of the prepreg according to any one of claims 7 to 9.

11. A high pressure gas container comprising the fiber reinforced composite material of claim 10.

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