WO2014203797A1 - Epoxy resin composition and cured article thereof, prepreg, and fiber-reinforced composite material - Google Patents

Abstract

The purpose of the present invention is to provide an epoxy resin composition the qualities and viscosity of which are easily controlled, which it is possible to easily cure within a short time and at low temperature, and which can form a cured article of exceptional mechanical characteristics such as high tensile elongation at break, and having high heat resistance, as well as cured article thereof (cured resin article). The present invention pertains to an epoxy resin composition characterized by including (A) an alicyclic epoxy compound, (B) at least one type of compound selected from the group consisting of (B1) lactone addition compounds having hydroxyl groups and (B2) polycarbonate polyols, and (C) a polyvinyl acetal resin.

Description

Epoxy resin composition and cured product thereof, prepreg, and fiber-reinforced composite material

The present invention relates to an epoxy resin composition and a cured product thereof, a prepreg obtained by impregnating or coating a reinforcing fiber with the epoxy resin composition, and a fiber-reinforced composite material obtained by curing the prepreg. This application claims the priority of Japanese Patent Application No. 2013-128160 for which it applied to Japan on June 19, 2013, and uses the content here.

Conventionally, epoxy resin compositions containing epoxy compounds (curable epoxy resin compositions) have been widely used for a wide variety of applications such as adhesives and structural materials. In recent years, development of a fiber-reinforced composite material obtained by further reinforcing a cured product obtained by curing the epoxy resin composition with reinforcing fibers such as carbon fibers has been energetically advanced. The above fiber reinforced composite material utilizes its light weight and tough properties, for example, automobile parts, civil engineering and building equipment, wind power blades, sports equipment, aircraft, ships, robots, cable materials, high pressure tanks, etc. Application as various components is expected.

Examples of the epoxy resin composition for forming the fiber reinforced composite material include, as a base material resin, bisphenol A type epoxy resin (bisphenol A diglycidyl ether), a curing agent, and a reactive diluent for epoxy resin. An epoxy resin composition or the like is known (see Patent Document 1).

Japanese Patent Laid-Open No. 9-12729

However, an epoxy resin composition containing an epoxy compound having a glycidyl group, such as a bisphenol A type epoxy resin, needs to be heated at a high temperature for a long time in order to be cured, which is problematic in terms of the productivity of the fiber-reinforced composite material. Had. Furthermore, the cured product obtained by curing the epoxy resin composition has low heat resistance and low mechanical strength such as low elongation (tensile elongation at break). From the viewpoint of mechanical properties of the fiber-reinforced composite material Had a problem.

In addition, epoxy resin compositions for forming fiber reinforced composite materials can be applied to a variety of molding methods, from liquid to solid, and in the case of liquids from low viscosity to high. It is required that the desired properties and viscosity can be easily controlled, such as those having a viscosity.

Therefore, the object of the present invention is to easily control the properties and viscosity, can be cured at a low temperature in a short time, has excellent mechanical properties such as high tensile elongation at break, and has high heat resistance. It is providing the epoxy resin composition which can form, and its hardened | cured material (resin hardened | cured material).
Furthermore, another object of the present invention is to provide fiber reinforcement excellent in productivity, heat resistance, and toughness obtained by curing a prepreg obtained by impregnating or coating the above-mentioned epoxy resin composition on a reinforcing fiber. It is to provide a composite material.

As a result of intensive studies to solve the above problems, the present inventor has an epoxy resin composition containing a specific epoxy compound, a specific compound having a hydroxyl group, and a polyvinyl formal resin, and the control of properties and viscosity is easy. It was found that it can be cured at a low temperature and in a short time, and by further curing, a cured product having excellent mechanical properties such as high tensile fracture elongation and high heat resistance can be formed, and the present invention has been completed. I let you.

That is, the present invention relates to an alicyclic epoxy compound (A), at least one compound (B) selected from the group consisting of a lactone addition compound (B1) having a hydroxyl group and a polycarbonate polyol (B2), and polyvinyl acetal. An epoxy resin composition comprising a resin (C) is provided.

Furthermore, the epoxy resin composition is provided in which the content of the compound (B) is 5 to 60 parts by weight with respect to 100 parts by weight of the alicyclic epoxy compound (A).

Furthermore, the above epoxy resin composition containing a curing catalyst (D) is provided.

Furthermore, the above epoxy resin composition, which is a resin composition for fiber reinforced composite materials, is provided.

The present invention also provides a cured product obtained by curing the above epoxy resin composition.

The present invention also provides a prepreg obtained by impregnating or coating the above-mentioned epoxy resin composition on reinforcing fibers.

The present invention also provides a fiber-reinforced composite material obtained by curing the prepreg.

That is, the present invention relates to the following.
[1] At least one compound (B) selected from the group consisting of an alicyclic epoxy compound (A), a lactone addition compound (B1) having a hydroxyl group and a polycarbonate polyol (B2), and a polyvinyl acetal resin (C The epoxy resin composition characterized by including this.
[2] The alicyclic epoxy compound (A) is (i) a compound having an epoxy group composed of two adjacent carbon atoms and oxygen atoms constituting the alicyclic ring, and (ii) an epoxy group on the alicyclic ring. The epoxy resin composition according to [1], which is at least one selected from the group consisting of compounds directly bonded by a single bond.
[3] The epoxy resin composition according to [2], wherein the compound having an epoxy group composed of two adjacent carbon atoms and oxygen atoms constituting the alicyclic ring is a compound having a cyclohexene oxide group. .
[4] (i) A compound having an epoxy group composed of two adjacent carbon atoms and oxygen atoms constituting an alicyclic ring is a compound represented by the following formula (I) [in the formula (I), X Represents a single bond or a linking group. ] The epoxy resin composition according to [2] or [3].
[5] (ii) A compound in which an epoxy group is directly bonded to the alicyclic ring by a single bond is a compound represented by the following formula (II): [wherein R ′ is a p-valent in the structural formula Is an organic group (organic residue) formed by removing p hydroxyl groups (—OH) from the alcohol, and p and n each represent a natural number. ] The epoxy resin composition according to any one of [2] to [4].
[6] Any of [1] to [5], wherein the content (blending amount) of the alicyclic epoxy compound (A) is 25 to 95% by weight with respect to the epoxy resin composition (100% by weight) The epoxy resin composition as described in one.
[7] The ratio of the alicyclic epoxy compound (A) to the total amount (100% by weight) of the alicyclic epoxy compound (A), the compound (B), and the polyvinyl acetal resin (C) is 25 to 95% by weight. The epoxy resin composition according to any one of [1] to [6].
[8] A structural unit in which the lactone addition compound (B1) having a hydroxyl group has one or more hydroxyl groups in the molecule and is formed by a ring-opening addition reaction (including ring-opening addition polymerization) of ε-caprolactone. The epoxy resin composition according to any one of [1] to [7], which is a compound having at least [—C (O) — (CH ₂ ) ₅ —O—] (ε-caprolactone addition compound) in the molecule object.
[9] The epoxy resin composition according to any one of [1] to [8], wherein the number (total number) of lactone units in the molecule of the lactone addition compound (B1) having a hydroxyl group is 2 to 40 object.
[10] The lactone addition compound (B1) having a hydroxyl group has a structure in which two or more lactone units are repeatedly directly bonded (polymerized), and the number of repeating lactone units (degree of polymerization) in the structure is 2 to 20 [ [1] The epoxy resin composition according to any one of [9].
[11] The epoxy resin composition according to any one of [1] to [10], wherein the lactone addition compound (B1) having a hydroxyl group has 2 to 10 hydroxyl groups in the molecule (total number). .
[12] A lactone addition compound (B1) having a hydroxyl group is a compound represented by the following formula (1): [wherein r represents an integer of 1 to 20; R ¹ represents an organic group (organic residue) formed by removing r hydroxyl groups from a compound [R ¹ (OH) _r ] having r hydroxyl groups in the molecule in the structural formula. q represents an integer of 0 to 10. R ² represents an alkylene group. ] The epoxy resin composition according to any one of [1] to [11].
[13] The epoxy resin composition according to any one of [1] to [12], wherein the number (total number) of hydroxyl groups in the polycarbonate polyol (B2) is 2 to 10.
[14] A compound in which the polycarbonate polyol (B2) is represented by the following formula (2) [in the formula (2), s represents an integer of 2 to 50. R ³ is the same or different and represents an alkylene group. ] The epoxy resin composition according to any one of [1] to [13].
[15] The epoxy resin composition according to any one of [1] to [14], wherein the hydroxyl value of the compound (B) is 10 to 800 mg KOH / g.
[16] The epoxy resin composition according to any one of [1] to [15], wherein the molecular weight of the compound (B) is 200 to 10,000.
[17] The epoxy resin composition according to any one of [1] to [16], wherein the viscosity (25 ° C.) of the compound (B) is 100 to 25000 mPa · s.
[18] The epoxy according to any one of [1] to [17], wherein the content of the compound (B) is 5 to 60 parts by weight with respect to 100 parts by weight of the alicyclic epoxy compound (A). Resin composition.
[19] The polyvinyl acetal resin (C) is a structural unit represented by the following formula (i) [in the formula (i), R ¹¹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. ], A structural unit represented by the following formula (ii), and a polyvinyl acetal resin containing a structural unit represented by the following formula (iii) as an essential structural unit: The epoxy resin composition described in 1.
[20] A polyvinyl acetal resin (C1) in which the polyvinyl acetal resin (C) contains the structural units represented by formulas (i) to (iii) as essential structural units and has no carboxyl group in the molecule, or The epoxy resin composition according to [19], which is a polyvinyl acetal resin (C2) containing a structural unit represented by formulas (i) to (iii) as an essential structural unit and having a carboxyl group in the molecule.
[21] The total content (total content) of the structural units represented by the formulas (i) to (iii) in the polyvinyl acetal resin (C1) is the total structural unit (100% by weight) constituting the polyvinyl acetal resin (C1). %)), The epoxy resin composition according to [20].
[22] The content (content) of the structural unit represented by the formula (i) in the polyvinyl acetal resin (C1) is based on the total structural units (100 mol%) constituting the polyvinyl acetal resin (C1). The epoxy resin composition according to [20] or [21], which is 50 to 80 mol%.
[23] The content (content) of the structural unit represented by the formula (ii) in the polyvinyl acetal resin (C1) is based on the total structural units (100 mol%) constituting the polyvinyl acetal resin (C1). The epoxy resin composition according to any one of [20] to [22], which is 0.1 to 49.9 mol%.
[24] The content (content) of the structural unit represented by the formula (iii) in the polyvinyl acetal resin (C1) is based on the total structural units (100 mol%) constituting the polyvinyl acetal resin (C1). The epoxy resin composition according to any one of [20] to [23], which is 0.1 to 49.9 mol%.
[25] The polyvinyl acetal resin (C2) is a structural unit represented by the following formula (vi) in addition to the structural units represented by the formulas (i) to (iii) [in the formula (vi), R ¹² represents Represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. ] The epoxy resin composition according to any one of [20] to [24], which is a polyvinyl acetal resin.
[26] Structural units represented by the formulas (i) to (iii) and (vi) in the polyvinyl acetal resin (C2) (the structural units represented by the formulas (i) to (iii) and the formula (vi) The total content (total content) of the structural units is 80 to 100% by weight with respect to all the structural units (100% by weight) constituting the polyvinyl acetal resin (C2) [20] to [25 ] The epoxy resin composition as described in any one of.
[27] The content (content) of the structural unit represented by the formula (i) in the polyvinyl acetal resin (C2) is based on the total structural units (100 mol%) constituting the polyvinyl acetal resin (C2). The epoxy resin composition according to any one of [20] to [26], which is 49.9 to 80 mol%.
[28] The content (content) of the structural unit represented by the formula (ii) in the polyvinyl acetal resin (C2) is based on the total structural units (100 mol%) constituting the polyvinyl acetal resin (C2). The epoxy resin composition according to any one of [20] to [27], which is 0.1 to 49.9 mol%.
[29] The content (content) of the structural unit represented by the formula (iii) in the polyvinyl acetal resin (C2) is based on the total structural units (100 mol%) constituting the polyvinyl acetal resin (C2). The epoxy resin composition according to any one of [20] to [28], which is 0.1 to 49.9 mol%.
[30] The content (content) of the structural unit represented by the formula (vi) in the polyvinyl acetal resin (C2) is based on the total structural units (100 mol%) constituting the polyvinyl acetal resin (C2). The epoxy resin composition according to any one of [20] to [29], which is 0.1 to 49.9 mol%.
[31] The epoxy resin composition according to any one of [1] to [30], wherein the polyvinyl acetal resin (C) has a weight average molecular weight of 40,000 to 140,000.
[32] Any of [1] to [31], wherein the content (blending amount) of the polyvinyl acetal resin (C) is 1 to 40 parts by weight with respect to 100 parts by weight of the alicyclic epoxy compound (A). The epoxy resin composition as described in one.
[33] The epoxy resin composition according to any one of [1] to [32], further comprising a curing catalyst (D).
[34] The content (blending amount) of the curing catalyst (D) is 0.01 to 15 parts by weight with respect to 100 parts by weight of the total amount of the cationic curable compound contained in the epoxy resin composition. The epoxy resin composition as described in any one.
[35] The epoxy resin composition according to any one of [1] to [34], which has a viscosity (25 ° C.) of less than 25000 Pa · s.
[36] The epoxy resin composition according to any one of [1] to [35], wherein the viscosity (30 ° C.) is less than 10,000 Pa · s.
[37] The epoxy resin composition according to any one of [1] to [36], which is a resin composition for fiber-reinforced composite materials.
[38] A cured product obtained by curing the epoxy resin composition according to any one of [1] to [37].
[39] A prepreg obtained by impregnating or coating a reinforcing fiber with the epoxy resin composition according to any one of [1] to [37].
[40] The prepreg according to [39], wherein the reinforcing fiber is at least one selected from the group consisting of carbon fiber, glass fiber, and aramid fiber.
[41] A fiber-reinforced composite material obtained by curing the prepreg according to [39] or [40].

Since the epoxy resin composition of the present invention has the above-described configuration, it can be cured at a low temperature and in a short time, and the properties and viscosity can be easily controlled. Furthermore, by curing the epoxy resin composition of the present invention, a cured product having excellent mechanical properties such as high tensile elongation at break and having high heat resistance can be formed with high productivity. Moreover, the fiber reinforced composite material excellent in productivity, heat resistance, and toughness can be obtained by hardening the prepreg obtained by coating or impregnating the reinforcing fiber with the epoxy resin composition of the present invention.

<Epoxy resin composition>
The epoxy resin composition (curable epoxy resin composition) of the present invention is at least one selected from the group consisting of an alicyclic epoxy compound (A), a lactone addition compound (B1) having a hydroxyl group, and a polycarbonate polyol (B2). It is a resin composition containing the seed compound (B) and the polyvinyl acetal resin (C) as essential components. In addition to the above essential components, the epoxy resin composition of the present invention may contain other components such as a curing catalyst (D) described later.

[Alicyclic epoxy compound (A)]
The alicyclic epoxy compound (A) in the epoxy resin composition of the present invention is a compound having at least an alicyclic (aliphatic hydrocarbon ring) structure and an epoxy group in the molecule (in one molecule). Specifically, as the alicyclic epoxy compound (A), (i) an epoxy group composed of two adjacent carbon atoms and oxygen atoms constituting the alicyclic ring (when referred to as “alicyclic epoxy group”) And (ii) a compound in which an epoxy group is directly bonded to the alicyclic ring with a single bond.

The compound having an epoxy group (alicyclic epoxy group) composed of two adjacent carbon atoms and oxygen atoms constituting the alicyclic ring (i) is arbitrarily selected from known or commonly used compounds. Can be used. Especially, as said alicyclic epoxy group, a cyclohexene oxide group is preferable.

As the compound having an epoxy group (alicyclic epoxy group) composed of two adjacent carbon atoms and oxygen atoms constituting the alicyclic ring (i), from the viewpoint of transparency and heat resistance, a cyclohexene oxide group is used. In particular, a compound (alicyclic epoxy compound) represented by the following formula (I) is preferable.

In the above formula (I), X represents a single bond or a linking group (a divalent group having one or more atoms). Examples of the linking group include divalent hydrocarbon groups, alkenylene groups in which part or all of carbon-carbon double bonds are epoxidized, carbonyl groups, ether bonds, ester bonds, carbonate groups, amide groups, and the like. And a group in which a plurality of are connected.

Examples of the compound in which X in the above formula (I) is a single bond include 3,4,3 ′, 4′-diepoxybicyclohexane and the like.

Examples of the divalent hydrocarbon group include a linear or branched alkylene group having 1 to 18 carbon atoms and a divalent alicyclic hydrocarbon group. Examples of the linear or branched alkylene group having 1 to 18 carbon atoms include a methylene group, a methylmethylene group, a dimethylmethylene group, an ethylene group, a propylene group, and a trimethylene group. Examples of the divalent alicyclic hydrocarbon group include 1,2-cyclopentylene group, 1,3-cyclopentylene group, cyclopentylidene group, 1,2-cyclohexylene group, 1,3-cyclopentylene group, And divalent cycloalkylene groups (including cycloalkylidene groups) such as cyclohexylene group, 1,4-cyclohexylene group, and cyclohexylidene group.

Examples of the alkenylene group in the alkenylene group in which part or all of the carbon-carbon double bond is epoxidized (sometimes referred to as “epoxidized alkenylene group”) include, for example, vinylene group, propenylene group, 1-butenylene group And straight-chain or branched alkenylene groups having 2 to 8 carbon atoms such as 2-butenylene group, butadienylene group, pentenylene group, hexenylene group, heptenylene group and octenylene group. In particular, the epoxidized alkenylene group is preferably an alkenylene group in which all of the carbon-carbon double bonds are epoxidized, more preferably 2 to 4 carbon atoms in which all of the carbon-carbon double bonds are epoxidized. Alkenylene group.

The linking group X is particularly preferably a linking group containing an oxygen atom, specifically, —CO—, —O—CO—O—, —COO—, —O—, —CONH—, epoxidation. An alkenylene group; a group in which a plurality of these groups are linked; a group in which one or more of these groups are linked to one or more of divalent hydrocarbon groups, and the like. Examples of the divalent hydrocarbon group include those exemplified above.

Representative examples of the alicyclic epoxy compounds represented by the above formula (I) include compounds represented by the following formulas (I-1) to (I-10), bis (3,4-epoxycyclohexylmethyl) ) Ether, 1,2-bis (3,4-epoxycyclohexane-1-yl) ethane, 1,2-epoxy-1,2-bis (3,4-epoxycyclohexane-1-yl) ethane, 2,2 -Bis (3,4-epoxycyclohexane-1-yl) propane and the like. In the following formulas (I-5) and (I-7), l and m each represents an integer of 1 to 30. R in the following formula (I-5) is an alkylene group having 1 to 8 carbon atoms, and is a methylene group, ethylene group, propylene group, isopropylene group, butylene group, isobutylene group, s-butylene group, pentylene group, hexylene. And linear or branched alkylene groups such as a group, heptylene group, and octylene group. Among these, linear or branched alkylene groups having 1 to 3 carbon atoms such as a methylene group, an ethylene group, a propylene group, and an isopropylene group are preferable. N1 to n6 in the following formulas (I-9) and (I-10) each represents an integer of 1 to 30.

Examples of the compound (ii) in which the epoxy group is directly bonded to the alicyclic ring with a single bond include compounds represented by the following formula (II).

In the formula (II), R ′ is an organic group (organic residue) formed by removing p hydroxyl groups (—OH) from a p-valent alcohol in the structural formula, and p and n each represent a natural number. To express. Examples of the p-valent alcohol [R ′ (OH) _p ] include polyhydric alcohols such as 2,2-bis (hydroxymethyl) -1-butanol (such as alcohols having 1 to 15 carbon atoms) described later And compounds having r hydroxyl groups. p is preferably 1 to 6, and n is preferably 1 to 30. When p is 2 or more, n in each group in () (inside the outer parenthesis) may be the same or different. Specific examples of the compound represented by the above formula (II) include 1,2-epoxy-4- (2-oxiranyl) cyclohexane adduct of 2,2-bis (hydroxymethyl) -1-butanol [for example, , Trade name “EHPE3150” (manufactured by Daicel Corporation) and the like.

In the epoxy resin composition of the present invention, the alicyclic epoxy compound (A) can be used alone or in combination of two or more. In addition, as the alicyclic epoxy compound (A), for example, commercially available products such as trade names “Celoxide 2021P” and “Celoxide 2081” (manufactured by Daicel Corporation) may be used.

Examples of the alicyclic epoxy compound (A) include compounds represented by the above formula (I-1) [3,4-epoxycyclohexylmethyl (3,4-epoxy) cyclohexanecarboxylate; for example, trade name “Celoxide 2021P”. (Daicel Co., Ltd.) etc. are particularly preferred.

The content (blending amount) of the alicyclic epoxy compound (A) in the epoxy resin composition of the present invention is not particularly limited, but is preferably 25 to 95% by weight with respect to the epoxy resin composition (100% by weight). More preferably, it is 35 to 85% by weight, still more preferably 45 to 80% by weight. By controlling the content of the alicyclic epoxy compound (A) in the above range, the curability of the epoxy resin composition tends to be higher, and the heat resistance and mechanical strength of the cured product tend to be further improved.

In the epoxy resin composition of the present invention, the ratio of the alicyclic epoxy compound (A) to the total amount (100% by weight) of the alicyclic epoxy compound (A), the compound (B), and the polyvinyl acetal resin (C) is: Although not particularly limited, it is preferably 25 to 95% by weight, more preferably 35 to 85% by weight, and still more preferably 45 to 80% by weight. By setting the ratio of the alicyclic epoxy compound (A) to 25% by weight or more, the curability of the epoxy resin composition tends to be further improved, and the heat resistance of the cured product tends to be further improved. On the other hand, when the ratio of the alicyclic epoxy compound (A) is 95% by weight or less, the mechanical properties tend to be improved, for example, the tensile strength at break of the cured product is increased.

[Compound (B)]
The compound (B) in the epoxy resin composition of the present invention is at least one compound selected from the group consisting of a lactone addition compound (B1) having a hydroxyl group and a polycarbonate polyol (B2). When the epoxy resin composition of the present invention contains the compound (B) as an essential component, the mechanical strength of the cured product tends to be improved, for example, the tensile elongation at break is increased.

The lactone addition compound (B1) having a hydroxyl group is a structural unit having one or more hydroxyl groups in the molecule and formed by a ring-opening addition reaction (including ring-opening addition polymerization) of a lactone compound (lactone). A compound having at least [—C (O) —R ^L —O—] (R ^L represents an alkylene group) (sometimes referred to as “lactone unit”) in the molecule. Examples of the lactone compound include known and commonly used lactone compounds and are not particularly limited, and examples thereof include 4- to 10-membered ring lactone compounds such as γ-butyrolactone, δ-valerolactone, and ε-caprolactone. Among these, ε-caprolactone is preferable as the lactone compound. That is, as the lactone addition compound (B1) having a hydroxyl group, a structural unit having one or more hydroxyl groups in the molecule and formed by a ring-opening addition reaction (including ring-opening addition polymerization) of ε-caprolactone. A compound (ε-caprolactone addition compound) having at least [—C (O) — (CH ₂ ) ₅ —O—] in the molecule is preferred. In addition, the lactone addition compound (B1) having a hydroxyl group may have only one kind of the lactone unit, or may have two or more kinds.

The number (total number) of lactone units in the molecule of the lactone addition compound (B1) having a hydroxyl group is not particularly limited as long as it is 1 or more, but 2 or more (for example, 2 to 40) is preferable. Further, when the lactone addition compound (B1) having a hydroxyl group has a structure in which two or more lactone units are repeatedly directly bonded (polymerized), the number of repeating lactone units (degree of polymerization) in the structure is not particularly limited. ~ 20 are preferred. Moreover, the addition form of the lactone unit in the said structure is not specifically limited, A random type may be sufficient and a block type may be sufficient.

The number (total number) of hydroxyl groups in the molecule of the lactone addition compound (B1) having a hydroxyl group is not particularly limited as long as it is 1 or more, but is preferably 2 or more (for example, 2 to 10), more preferably. Is 2-4.

The lactone addition compound (B1) having a hydroxyl group is not particularly limited. For example, in the presence of a compound (initiator) having one or more hydroxyl groups in the molecule, the lactone compound is subjected to a ring-opening addition reaction (also known as ring-opening addition polymerization). To be included). Examples of the compound having one or more hydroxyl groups in the molecule include aliphatic alcohols such as methanol, ethanol, propanol, butanol, pentanol, hexanol and octanol; aromatic alcohols such as benzyl alcohol; ethylene glycol, diethylene glycol, Triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, pentanediol, methylpentanediol, 2,4-diethylpentanediol, 1,6-hexanediol, 2-ethyl-1,3-hexanediol, neopentyl glycol, neopentyl glycol ester, cyclohexanedimethanol, glycerin, diglycerin, polyglycerin, Polyhydric alcohols such as limethylolpropane, ditrimethylolpropane, pentaerythritol, dipentaerythritol, hydrogenated bisphenol A, hydrogenated bisphenol F, hydrogenated bisphenol S; phenol, biphenol, cresol, catechol, pyrogallol, hydroquinone, hydroquinone monomethyl ether Bisphenol A, bisphenol F, 4,4′-dihydroxybenzophenone, bisphenol S, alkylene oxide adduct of bisphenol A, alkylene oxide adduct of bisphenol F, alkylene oxide adduct of bisphenol S, phenol novolac resin, cresol novolac resin, etc. Phenols: polyvinyl alcohol, polyvinyl acetate partial hydrolyzate, starch, acrylic Cellulose polymers such as all, styrene-allyl alcohol copolymer resin, polyester polyol, polycaprolactone polyol, polypropylene polyol, polytetramethylene glycol, polycarbonate polyol, polybutadiene having a hydroxyl group, cellulose, cellulose acetate, cellulose acetate butyrate, and hydroxyethyl cellulose Examples thereof include oligomers or polymers having a hydroxyl group. In particular, from the viewpoint of reactivity with the alicyclic epoxy compound (A), the lactone addition compound (B1) having a hydroxyl group includes a lactone addition compound having two or more hydroxyl groups in the molecule (particularly, ε-caprolactone addition). Compound), and more preferably, a lactone addition compound having two or more structures having a hydroxyl group at the end of the lactone unit (that is, —C (O) —R ^L —OH) in the molecule.

The ring-opening addition reaction of the lactone compound can be carried out by a known or conventional method, and is not particularly limited. For example, the lactone compound is stirred and mixed in the presence of an initiator while heating as necessary. Can be implemented. In addition, the usage-amount (preparation amount) of an initiator and a lactone compound can be suitably adjusted according to the molecular weight etc. of the target lactone adduct, and is not specifically limited. In addition, in the above ring-opening addition reaction, a known or conventional catalyst such as tetrabutyl titanate, tetraisopropyl titanate, tetraethyl titanate, dibutyltin oxide, dibutyltin laurate, tin octylate, stannous chloride is used as necessary. You can also The usage-amount of a catalyst can be suitably selected according to the kind of initiator, a lactone compound, reaction conditions, etc., and is not specifically limited.

Polycarbonate polyol (B2) is a compound having two or more hydroxyl groups in the molecule and at least a carbonate skeleton in the molecule. Polycarbonate polyol (B2) can be prepared by the same phosgene method as in the usual method for producing carbonate polyol, or a carbonate exchange reaction using dialkyl carbonate or diphenyl carbonate such as dimethyl carbonate and diethyl carbonate (Japanese Patent Laid-Open Nos. 62-187725 and 2). -175721, JP-A-2-49025, JP-A-3-220233, JP-A-3-252420, etc.). Since the carbonate bond is difficult to undergo thermal decomposition, the cured product of the resin composition containing the polycarbonate polyol (B2) tends to exhibit excellent stability even under high temperature and high humidity.

The polyol used in the carbonate exchange reaction together with the dialkyl carbonate includes 1,6-hexanediol, ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 2,3- Butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanedimethanol, 1,12-dodecanediol, butadiene diol, neopentyl glycol, tetramethylene glycol, propylene glycol, Examples include dipropylene glycol.

The number (total number) of hydroxyl groups in the polycarbonate polyol (B2) is not particularly limited as long as it is 2 or more, but is preferably 2 to 10, more preferably 2 to 4.

More specifically, examples of the compound (B) include a compound represented by the following formula (1) and a compound represented by the following formula (2).

In the formula (1), r represents an integer of 1 to 20. r is preferably an integer of 2 to 4. In formula (1), R ¹ is an organic group (organic residue) formed by removing r hydroxyl groups from a compound [R ¹ (OH) _r ] having r hydroxyl groups in the molecule in the structural formula. Indicates. Examples of the organic group include an organic group formed by removing r hydroxyl groups from a compound having one or more (r groups) hydroxyl groups in the above-described molecule in the structural formula.

In the formula (1), q means the number of repetitions of the structure (lactone unit) in parentheses with q, and represents an integer of 0 to 10. However, the total number of q in Formula (1) is an integer of 1 or more. In addition, when r is an integer greater than or equal to 2, several q may be the same and may differ.

R ² in the formula (1) represents an alkylene group, and has, for example, methylene group, methylmethylene group, dimethylmethylene group, ethylene group, propylene group, trimethylene group, tetramethylene group, pentamethylene group, etc. -18 linear or branched alkylene groups. Among these, as R ² , a pentamethylene group is preferable. In addition, when several R < ² > exists in Formula (1), these may be the same and may differ. Moreover, the addition form of the structure (lactone unit) in parentheses to which q is attached is not particularly limited, and may be a random type or a block type.

In the formula (2), s represents an integer of 2 to 50. R ³ in formula (2) is the same or different and represents an alkylene group, and examples thereof are the same as those for R ² in formula (1). In addition, several R < ³ > in the parenthesis attached | subjected s may be the same, and may differ. Moreover, the addition form of the structure in the parentheses to which s is attached (carbonate skeleton) is not particularly limited, and may be a random type or a block type.

The hydroxyl value of the compound (B) is not particularly limited, but is preferably 10 to 800 mgKOH / g, more preferably 50 to 600 mgKOH / g. By setting the hydroxyl value to 10 mgKOH / g or more, the heat resistance of the cured product tends to be further improved. On the other hand, when the hydroxyl value is 800 mgKOH / g or less, the mechanical properties of the cured product tend to be further improved. The hydroxyl value of the compound (B) can be measured according to JIS K0070.

The molecular weight of the compound (B) is not particularly limited, but is preferably 200 to 10000, more preferably 300 to 3000. By setting the molecular weight to 200 or more, there is a tendency that the effects of lowering the elastic modulus and improving the bending strength can be enjoyed more efficiently. On the other hand, when the molecular weight is 10,000 or less, the heat resistance and mechanical strength of the cured product tend to be further improved. In addition, the molecular weight of a compound (B) can be measured as a molecular weight of standard polystyrene conversion by gel permeation chromatography.

Compound (B) may be liquid at 25 ° C. or may be solid. When the compound (B) is a liquid at 25 ° C., the viscosity (25 ° C.) is not particularly limited, but is preferably 100 to 25000 mPa · s, more preferably 500 to 10000 mPa · s.

In the epoxy resin composition of the present invention, the compound (B) can be used alone or in combination of two or more. As the compound (B), for example, trade names “Placcel 205”, “Placcel 205U”, “Placcel L205AL”, “Placcel 208”, “Placcel 210”, “Placcel 210N”, “Placcel 212”, “Placcel” L212AL, Plaxel 220, Plaxel 220N, Plaxel 220NP1, Plaxel L220AL, Plaxel 230, Plaxel 230N, Plaxel 240, Plaxel 303, Plaxel 305, Plaxel "308", "Placcel 312", "Placcel L320AL", "Placcel 405D", "Placcel CD205", "Placcel CD210", "Placcel CD220", "Placcel CD205PL", "Placcel C" "205HL", "Plaxel CD210PL", "Plaxel CD210HL", "Plaxel CD220PL", "Plaxel CD220HL", "Plaxel CD220EC", "Plaxel CD221T" (manufactured by Daicel Co., Ltd.); trade name "ETERNACOLL UH-CARB50" , “ETERRNACOLL UH-CARB100”, “ETERNACOLL UH-CARB300”, “ETERNACOLL UH-CARB90 (1/3)”, “ETERNACOLL UH-CARB90 (1/1)”, “ETERNACOLL UH-CARB100” Product name “Duranol T6002”, “Duranol T5652”, “Duranol T4672”, “Duranol T469” "," Deyuranoru G3452 "(above, Asahi Kasei Chemicals Co., Ltd.) can also be used commercially available products, such as.

The content (blending amount) of the compound (B) in the epoxy resin composition of the present invention is not particularly limited, but is preferably 5 to 60 parts by weight with respect to 100 parts by weight of the alicyclic epoxy compound (A). The amount is preferably 10 to 60 parts by weight, more preferably 15 to 55 parts by weight, and particularly preferably 20 to 50 parts by weight. By setting the content of the compound (B) to 5 parts by weight or more, the tensile strength at break of the cured product tends to be high, and the mechanical strength tends to be further improved. On the other hand, when the content of the compound (B) is 60 parts by weight or less, the glass transition temperature of the cured product is kept high, and the heat resistance tends to be further improved.

[Polyvinyl acetal resin (C)]
The polyvinyl acetal resin (C) in the epoxy resin composition of the present invention is obtained by reacting a polyvinyl alcohol resin containing at least a structural unit corresponding to vinyl alcohol (sometimes referred to as “vinyl alcohol structural unit”) with an aldehyde, It is a compound (polymer) containing one or two or more structures in which adjacent vinyl alcohol structural units in the polyvinyl alcohol resin are acetalized. The epoxy resin composition of the present invention contains the polyvinyl acetal resin (C) as an essential component, and in particular, while maintaining excellent mechanical strength of the cured product such as high tensile breaking elongation, the glass transition temperature and the thermal decomposition temperature. Tends to improve the heat resistance of the cured product. Furthermore, the property and viscosity of the epoxy resin composition can be easily controlled by selecting the molecular weight of the polyvinyl acetal resin (C).

Examples of the polyvinyl acetal resin (C) include known or conventional polyvinyl acetal resins, and are not particularly limited. For example, the structural unit represented by the following formula (i), the structural unit represented by the following formula (ii), And a polyvinyl acetal resin containing a structural unit represented by the following formula (iii) as an essential structural unit. More specifically, examples of the polyvinyl acetal resin (C) include polyvinyl formal resins in which R ¹¹ in the following formula (i) is a hydrogen atom.

The structural unit represented by the above formula (i) is a structural unit having an acetal moiety, and can be formed, for example, by a reaction between a continuous (adjacent) vinyl alcohol structural unit and an aldehyde (R ¹¹ —CHO). R ¹¹ in the structural unit represented by the formula (i) is an arbitrary group or atom, and examples thereof include a hydrogen atom, an alkyl group, an alkoxy group, and an aryl group. However, when R ¹¹ in the structural unit represented by the formula (i) is a bulky group (for example, a hydrocarbon group having a large number of carbon atoms), the softening point of the polyvinyl acetal resin (C) tends to decrease. The epoxy resin composition containing the polyvinyl acetal resin (C) having a low softening point may have a viscosity that is greatly reduced at a high temperature and the resin may flow too much. Further, the polyvinyl acetal resin (C) in which R ¹¹ is a bulky group has high solubility in a solvent, but on the other hand, tends to be inferior in chemical resistance. Thus, R ¹¹ in the formula (i) is preferably a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Examples of the alkyl group having 1 to 5 carbon atoms include linear or branched alkyl groups having 1 to 5 carbon atoms such as a methyl group, an ethyl group, a propyl group, and an isopropyl group.

The structural unit represented by the above formula (ii) is a structural unit corresponding to vinyl acetate, and the structural unit represented by the above formula (iii) is a structural unit corresponding to vinyl alcohol. In general, the structural unit corresponding to vinyl acetate is formed by polymerization of vinyl acetate, and the structural unit corresponding to vinyl alcohol is formed by saponifying the structural unit corresponding to vinyl acetate.

The polyvinyl acetal resin (C) includes structural units represented by formulas (i) to (iii) (a structural unit represented by formula (i), a structural unit represented by formula (ii), and a formula (iii) It may have a structural unit other than the structural unit represented by Examples of such a structural unit include a structural unit represented by the following formula (iv) (intermolecular acetal unit) and a structural unit represented by the following formula (v) (hemiacetal unit). R ¹¹ in formula (iv) and formula (v) is the same as that in formula (i).

More specifically, as the polyvinyl acetal resin (C), for example, a polyvinyl acetal containing a structural unit represented by formulas (i) to (iii) as an essential structural unit and having no carboxyl group in the molecule. Resin (sometimes referred to as “polyvinyl acetal resin (C1)”); polyvinyl acetal containing the structural units represented by the above formulas (i) to (iii) as essential structural units and having a carboxyl group in the molecule Resin (may be referred to as “polyvinyl acetal resin (C2)”) and the like.

The total content (total content) of the structural units represented by the above formulas (i) to (iii) in the polyvinyl acetal resin (C1) is not particularly limited, but all the structural units constituting the polyvinyl acetal resin (C1) 80 to 100% by weight is preferable with respect to (100% by weight).

In the polyvinyl acetal resin (C1), the structural units represented by the formulas (i) to (iii) may be regularly arranged or randomly arranged. That is, the polyvinyl acetal resin (C1) may be a block copolymer, an alternating copolymer or the like, or a random copolymer. Among them, it is preferable that they are arranged at random.

Although content (content rate) of the structural unit represented by Formula (i) in polyvinyl acetal resin (C1) is not specifically limited, With respect to all the structural units (100 mol%) which comprise polyvinyl acetal resin (C1). Therefore, 50 to 80 mol% is preferable. When the content of the structural unit represented by the formula (i) is 50 mol% or more, the chemical resistance, flexibility, wear resistance, and mechanical strength of the polyvinyl acetal resin (C1) tend to be further improved. There is. On the other hand, making the structural unit represented by formula (i) higher than 80 mol% tends to be difficult in production. That is, the structural unit represented by the formula (i) in the polyvinyl acetal resin (C1) is formed by acetalizing a vinyl alcohol structural unit existing continuously (adjacent) in the molecular chain in the polyvinyl alcohol resin. As a result, discontinuous vinyl alcohol structural units cannot be acetalized, and as a result, it is difficult to make the content of the structural unit represented by the formula (i) higher than 80 mol%. Tend.

Although content (content rate) of the structural unit represented by Formula (ii) in polyvinyl acetal resin (C1) is not specifically limited, With respect to all the structural units (100 mol%) which comprise polyvinyl acetal resin (C1). The content is preferably 0.1 to 49.9 mol%, more preferably 1 to 30 mol%. By setting the content of the structural unit represented by the formula (ii) to 0.1 mol% or more, the solubility of the polyvinyl acetal resin (C1) in the solvent and the dissolution in the alicyclic epoxy compound (A), etc. Tend to be more improved. On the other hand, by setting the content of the structural unit represented by the formula (ii) to 49.9 mol% or less, the amount of the structural unit represented by the formula (i) can be relatively increased, and the polyvinyl acetal resin ( The chemical resistance, flexibility, wear resistance, and mechanical strength of C1) are further improved, and the expected performance tends to be exhibited more easily.

Although content (content rate) of the structural unit represented by Formula (iii) in polyvinyl acetal resin (C1) is not specifically limited, With respect to all the structural units (100 mol%) which comprise polyvinyl acetal resin (C1). The content is preferably 0.1 to 49.9 mol%, more preferably 1 to 30 mol%. By setting the content of the structural unit represented by the formula (iii) to 49.9 mol% or less, the solubility of the polyvinyl acetal resin (C1) in the solvent and the dissolution in the alicyclic epoxy compound (A), etc. Tend to be more improved. In production of the polyvinyl acetal resin (C1), when acetalizing a vinyl alcohol structural unit that is continuous (adjacent) to the polyvinyl alcohol resin, the structural unit represented by the formula (ii) and the formula (iii) are used. Since the structural unit is in an equilibrium relationship, the content of the structural unit represented by the formula (iii) is usually 0.1 mol% or more.

The content of each structural unit (for example, structural units represented by formulas (i) to (iii)) in the polyvinyl acetal resin (C1) can be measured according to JIS K6729.

As described above, the polyvinyl acetal resin (C2) is a polyvinyl acetal resin having a carboxyl group in the molecule. As the polyvinyl acetal resin (C2), for example, in addition to the structural units represented by the above formulas (i) to (iii), a polyvinyl acetal resin containing a structural unit represented by the following formula (vi) (by copolymerization) And a polyvinyl acetal resin having a carboxyl group introduced therein (sometimes referred to as a “carboxyl group-introduced polyvinyl acetal resin”).

In the above formula (vi), R ¹² represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Examples of the alkyl group having 1 to 5 carbon atoms include linear or branched alkyl groups having 1 to 5 carbon atoms such as a methyl group, an ethyl group, a propyl group, and an isopropyl group.

Structural units represented by formulas (i) to (iii) and (vi) in the polyvinyl acetal resin (C2) (constituent units represented by formulas (i) to (iii) and a structure represented by formula (vi)) The total content (total content) of the units is not particularly limited, but is preferably 80 to 100% by weight with respect to all the structural units (100% by weight) constituting the polyvinyl acetal resin (C2). The polyvinyl acetal resin (C2) may further contain other structural units such as the structural unit represented by the above formula (iv) and the structural unit represented by the formula (v).

In the polyvinyl acetal resin (C2), the structural units represented by the formulas (i) to (iii) and (vi) may be arranged with regularity or may be arranged randomly. That is, the polyvinyl acetal resin (C2) may be a block copolymer, an alternating copolymer or the like, or a random copolymer. Among them, it is preferable that they are arranged at random.

Although content (content rate) of the structural unit represented by Formula (i) in polyvinyl acetal resin (C2) is not specifically limited, With respect to all the structural units (100 mol%) which comprise polyvinyl acetal resin (C2). Therefore, 49.9 to 80 mol% is preferable. By setting the content of the structural unit represented by formula (i) to 49.9 mol% or more, the chemical resistance, flexibility, wear resistance, and mechanical strength of the polyvinyl acetal resin (C2) are further improved. Tend to. On the other hand, making the structural unit represented by formula (i) higher than 80 mol% tends to be difficult in production. That is, the structural unit represented by the formula (i) in the polyvinyl acetal resin (C2) is formed by acetalizing a vinyl alcohol structural unit existing continuously (adjacent) in the molecular chain in the polyvinyl alcohol resin. As a result, discontinuous vinyl alcohol structural units cannot be acetalized, and as a result, it is difficult to make the content of the structural unit represented by the formula (i) higher than 80 mol%. Tend.

Although content (content rate) of the structural unit represented by Formula (ii) in polyvinyl acetal resin (C2) is not specifically limited, With respect to all the structural units (100 mol%) which comprise polyvinyl acetal resin (C2). The content is preferably 0.1 to 49.9 mol%, more preferably 1 to 30 mol%. By setting the content of the structural unit represented by the formula (ii) to 0.1 mol% or more, the solubility of the polyvinyl acetal resin (C2) in the solvent and the dissolution in the alicyclic epoxy compound (A), etc. Tend to be more improved. On the other hand, by setting the content of the structural unit represented by the formula (ii) to 49.9 mol% or less, the amount of the structural unit represented by the formula (i) can be relatively increased, and the polyvinyl acetal resin ( The chemical resistance, flexibility, wear resistance, and mechanical strength of C2) tend to be further improved, and the expected performance tends to be exhibited more easily.

Although content (content rate) of the structural unit represented by Formula (iii) in polyvinyl acetal resin (C2) is not specifically limited, With respect to all the structural units (100 mol%) which comprise polyvinyl acetal resin (C2). The content is preferably 0.1 to 49.9 mol%, more preferably 1 to 30 mol%. By setting the content of the structural unit represented by the formula (iii) to 49.9 mol% or less, the solubility of the polyvinyl acetal resin (C2) in the solvent and the dissolution in the alicyclic epoxy compound (A), etc. Tend to be more improved. In the production of the polyvinyl acetal resin (C2), when the polyvinyl alcohol chain continuous (adjacent) to the polyvinyl alcohol resin is acetalized, the constitutional unit represented by the formula (ii) and the constitution represented by the formula (iii) Since the units are in an equilibrium relationship, the content of the structural unit represented by the formula (iii) is usually 0.1 mol% or more.

Although content (content rate) of the structural unit represented by Formula (vi) in polyvinyl acetal resin (C2) is not specifically limited, With respect to all the structural units (100 mol%) which comprise polyvinyl acetal resin (C2). The content is preferably 0.1 to 49.9 mol%, more preferably 1 to 30 mol%. By setting the content of the structural unit represented by formula (vi) to 0.1 mol% or more, the adhesion (adhesion) between the resin and the reinforcing fiber in the fiber-reinforced composite material is improved, and the fiber-reinforced composite material There is a tendency for the mechanical properties of to improve. On the other hand, by setting the content of the structural unit represented by the formula (vi) to 49.9 mol% or less, the amount of the structural unit represented by the formula (i) can be relatively increased, and a polyvinyl acetal resin ( The chemical resistance, flexibility, wear resistance, and mechanical strength of C2) tend to be further improved, and the expected performance tends to be exhibited more easily.

Each content of each structural unit (for example, structural units represented by formulas (i) to (iii) and (vi)) in the polyvinyl acetal resin (C2) can be measured according to JIS K6729.

The weight average molecular weight of the polyvinyl acetal resin (C) is not particularly limited, but is preferably 40,000 to 140,000, more preferably 40,000 to 80,000. By setting the weight average molecular weight to 40000 or more, the moldability of the epoxy resin composition is further improved, and the bending strength and tensile strength of the cured product and the fiber-reinforced composite material tend to be further improved. On the other hand, when the weight average molecular weight is 140000 or less, workability is ensured without excessively increasing the viscosity of the epoxy resin composition while ensuring sufficient solubility in the alicyclic epoxy compound (A) and the like. There is a tendency to improve.

In the epoxy resin composition of the present invention, the polyvinyl acetal resin (C) can be used alone or in combination of two or more. Examples of the polyvinyl acetal resin (C) include, for example, trade names “VINYREC PVF-K”, “VINYREC PVF-L”, “VINYREC PVF-H”, “VINYREC PVF-E”, “VINYREC C” (above, Commercial products such as JNC Co., Ltd.) can also be used.

The content (blending amount) of the polyvinyl acetal resin (C) in the epoxy resin composition of the present invention can be appropriately adjusted according to the desired properties and viscosity of the epoxy resin composition, and is not particularly limited. The amount is preferably 1 to 40 parts by weight, more preferably 1 to 30 parts by weight, and still more preferably 1 to 20 parts by weight with respect to 100 parts by weight of the cyclic epoxy compound (A). By setting the content of the polyvinyl acetal resin (C) to 1 part by weight or more, the viscosity of the epoxy resin composition can be controlled to an appropriate range, so that the width of the molding method to which the epoxy resin composition can be applied is expanded. In addition, the mechanical strength of the cured product and the fiber-reinforced composite material tends to be further improved. On the other hand, by setting the content of the polyvinyl acetal resin (C) to 40 parts by weight or less, the epoxy resin composition can be made into a liquid, and furthermore, the viscosity can be controlled to an appropriate range, so that it can be applied. There is a tendency for the width of the molding method to expand.

[Curing catalyst (D)]
The epoxy resin composition of the present invention may further contain a curing catalyst (D). The curing catalyst (D) in the epoxy resin composition of the present invention functions to cure the epoxy resin composition by initiating and / or accelerating a curing reaction (polymerization reaction) such as the alicyclic epoxy compound (A). It is a compound that has. The curing catalyst (D) is not particularly limited. For example, a cationic polymerization initiator (photocation polymerization initiator, thermal cation polymerization, which initiates polymerization by generating cationic species by applying light irradiation or heat treatment). Initiators, etc.), Lewis acid / amine complexes, Bronsted acid salts, imidazoles and the like.

Examples of the photocationic polymerization initiator as the curing catalyst (D) include hexafluoroantimonate salts, pentafluorohydroxyantimonate salts, hexafluorophosphate salts, hexafluoroarsenate salts, and more specifically. For example, triarylsulfonium hexafluorophosphate (eg, p-phenylthiophenyldiphenylsulfonium hexafluorophosphate), sulfonium salts such as triarylsulfonium hexafluoroantimonate (particularly, triarylsulfonium salts); diaryl iodonium hexafluorophosphate Diaryl iodonium hexafluoroantimonate, bis (dodecylphenyl) iodonium tetrakis (pentafluorophenyl) borate, Examples include iodonium salts such as donium [4- (4-methylphenyl-2-methylpropyl) phenyl] hexafluorophosphate; phosphonium salts such as tetrafluorophosphonium hexafluorophosphate; pyridinium salts such as N-hexylpyridinium tetrafluoroborate and the like. It is done. Examples of the cationic photopolymerization initiator include, for example, trade names “UVACURE 1590” (manufactured by Daicel Cytec Co., Ltd.); trade names “CD-1010”, “CD-1011”, “CD-1012” (above, the United States). Sartomer); trade name “Irgacure 264” (manufactured by BASF); trade name “CIT-1682” (manufactured by Nippon Soda Co., Ltd.); trade name “PHOTOINITIATOR 2074” (manufactured by Rhodia Japan) It can also be preferably used.

Examples of the thermal cationic polymerization initiator as the curing catalyst (D) include aryldiazonium salts, aryliodonium salts, arylsulfonium salts, allene-ion complexes, etc., and trade names “PP-33”, “CP-66”. "CP-77" (manufactured by ADEKA); trade name "FC-509" (manufactured by 3M); trade name "UVE1014" (manufactured by GE); trade name "Sun-Aid SI-60L", “Sun-Aid SI-80L”, “Sun-Aid SI-100L”, “Sun-Aid SI-110L”, “Sun-Aid SI-150L”, “SI-B3” (above, manufactured by Sanshin Chemical Industry Co., Ltd.); -24-61 "(manufactured by BASF); trade names" TA-60 "," TA-100 "," TA-120 "," TA-160 " Manufactured by B Ltd.) can be preferably used commercially available products such as. Further, as the thermal cationic polymerization initiator, a compound of a chelate compound of a metal such as aluminum or titanium and acetoacetic acid or diketones and a silanol such as triphenylsilanol, or a metal such as aluminum or titanium and acetoacetic acid or diketone Examples thereof include a compound of a chelate compound with a phenol and a phenol such as bisphenol S.

As the Lewis acid / amine complex as the curing catalyst (D), a known or commonly used Lewis acid / amine complex-based curing catalyst can be used, and is not particularly limited. For example, BF ₃ .n-hexylamine, BF ₃ · monoethylamine, BF ₃ · benzylamine, BF ₃ · diethylamine, BF ₃ · piperidine, BF ₃ · triethylamine, BF ₃ · aniline, BF ₄ - n-hexylamine, BF ₄ - monoethylamine, BF ₄ - benzylamine , BF ₄ · diethylamine, BF ₄ · piperidine, BF ₄ · triethylamine, BF ₄ · aniline, PF ₅ · ethylamine, PF ₅ · isopropylamine, PF ₅ · butylamine, PF ₅ · laurylamine, PF ₅ · benzylamine, AsF _5. Laurylamine etc. are mentioned.

As the Bronsted acid salts as the curing catalyst (D), known or commonly used Bronsted acid salts can be used, and are not particularly limited. For example, aliphatic sulfonium salts, aromatic sulfonium salts, iodonium salts, phosphoniums. Examples include salts.

As the imidazole as the curing catalyst (D), known or commonly used imidazoles can be used, and are not particularly limited. For example, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-undecyl Imidazole, 2-heptadecylimidazole, 2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2- Undecylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2-methylimidazolium isocyanurate, 2-phenylimidazolium isocyanurate, 2,4 - Amino-6- [2-methylimidazolyl- (1)]-ethyl-s-triazine, 2,4-diamino-6- [2-ethyl-4-methylimidazolyl- (1)]-ethyl-s-triazine, etc. Is mentioned.

In the epoxy resin composition of the present invention, the curing catalyst (D) can be used singly or in combination of two or more.

The content (blending amount) of the curing catalyst (D) in the epoxy resin composition of the present invention is not particularly limited, but is a cationic curable compound (for example, alicyclic epoxy compound (A)) contained in the epoxy resin composition. Is preferably 0.01 to 15 parts by weight, more preferably 0.01 to 12 parts by weight, still more preferably 0.05 to 10 parts by weight, and particularly preferably 0.05 to 8 parts by weight with respect to 100 parts by weight as a whole. Part. By using the curing catalyst (D) within the above range, the curing rate of the epoxy resin composition is increased, and the balance between the heat resistance and the transparency of the cured product tends to be improved.

[Curing agent (E)]
The epoxy resin composition of the present invention may further contain a curing agent (E) (for example, instead of the curing catalyst (D)). The curing agent (E) in the epoxy resin composition of the present invention is a compound having a function of curing the epoxy resin composition by reacting with the alicyclic epoxy compound (A) or the like. As the curing agent (E), a known or conventional curing agent can be used as a curing agent for epoxy resin, and is not particularly limited. For example, acid anhydrides (acid anhydride curing agents), amines ( Amine curing agents), polyamide resins, imidazoles (imidazole curing agents), polymercaptans (polymercaptan curing agents), phenols (phenolic curing agents), polycarboxylic acids, dicyandiamides, organic acid hydrazides, etc. Can be mentioned.

As the acid anhydrides (acid anhydride-based curing agents) as the curing agent (E), known or commonly used acid anhydride-based curing agents can be used, and are not particularly limited. For example, methyltetrahydrophthalic anhydride Acids (4-methyltetrahydrophthalic anhydride, 3-methyltetrahydrophthalic anhydride, etc.), methylhexahydrophthalic anhydride (4-methylhexahydrophthalic anhydride, 3-methylhexahydrophthalic anhydride, etc.), dodecenyl anhydride Acid, methylendomethylenetetrahydrophthalic anhydride, phthalic anhydride, maleic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylcyclohexene dicarboxylic anhydride, pyromellitic anhydride, trimellitic anhydride, benzophenone tetracarboxylic anhydride Products, nadic anhydride, methyl nadic anhydride, Hydrogenated methyl nadic acid anhydride, 4- (4-methyl-3-pentenyl) tetrahydrophthalic anhydride, succinic anhydride, adipic anhydride, sebacic anhydride, dodecanedioic anhydride, methylcyclohexene tetracarboxylic anhydride, vinyl ether -Maleic anhydride copolymer, alkylstyrene-maleic anhydride copolymer and the like. Among these, acid anhydrides [for example, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, dodecenyl succinic anhydride, methylendomethylenetetrahydrophthalic anhydride, etc.] that are liquid at 25 ° C. are preferable from the viewpoint of handleability. On the other hand, the acid anhydride that is solid at 25 ° C., for example, can be dissolved in a liquid acid anhydride at 25 ° C. to form a liquid mixture, and as a curing agent (E) in the epoxy resin composition of the present invention. There is a tendency that the handleability of is improved. As the acid anhydride curing agent, saturated monocyclic hydrocarbon dicarboxylic acid anhydrides (including those in which a substituent such as an alkyl group is bonded to the ring) are preferable from the viewpoint of heat resistance and transparency of the cured product.

As the amines (amine-based curing agent) as the curing agent (E), known or conventional amine-based curing agents can be used, and are not particularly limited. For example, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylene Aliphatic amines such as pentamine, dipropylenediamine, diethylaminopropylamine, polypropylenetriamine; mensendiamine, isophoronediamine, bis (4-amino-3-methyldicyclohexyl) methane, diaminodicyclohexylmethane, bis (aminomethyl) cyclohexane, Cycloaliphatic polyamines such as N-aminoethylpiperazine, 3,9-bis (3-aminopropyl) -3,4,8,10-tetraoxaspiro (5,5) undecane; m-phenylenediamine, p-phenyle Diamine, tolylene-2,4-diamine, tolylene-2,6-diamine, mesitylene-2,4-diamine, 3,5-diethyltolylene-2,4-diamine, 3,5-diethyltolylene-2, Mononuclear polyamines such as 6-diamine; aromatic polyamines such as biphenylenediamine, 4,4-diaminodiphenylmethane, 2,5-naphthylenediamine, and 2,6-naphthylenediamine.

As the phenols (phenolic curing agent) as the curing agent (E), known or commonly used phenolic curing agents can be used, and are not particularly limited. For example, novolac type phenol resins, cresol type novolac resins, Examples include paraxylylene-modified phenol resins, aralkyl resins such as paraxylylene / metaxylylene-modified phenol resins, terpene-modified phenol resins, dicyclopentadiene-modified phenol resins, and triphenol propane.

Examples of the polyamide resin as the curing agent (E) include a polyamide resin having one or both of a primary amino group and a secondary amino group in the molecule.

As the imidazole (imidazole curing agent) as the curing agent (E), a known or commonly used imidazole curing agent can be used, and is not particularly limited. For example, 2-methylimidazole, 2-ethyl-4 -Methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methyl Imidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2-methylimidazolium isocyanurate, 2-phenyl Imidazolium Isocyanurate, 2,4-diamino-6- [2-methylimidazolyl- (1)]-ethyl-s-triazine, 2,4-diamino-6- [2-ethyl-4-methylimidazolyl- (1)] -Ethyl-s-triazine and the like.

Examples of the polymercaptans (polymercaptan-based curing agent) as the curing agent (E) include liquid polymercaptan and polysulfide resin.

Examples of polycarboxylic acids as the curing agent (E) include adipic acid, sebacic acid, terephthalic acid, trimellitic acid, carboxyl group-containing polyester, and the like.

Among these, as the curing agent (E), acid anhydrides (acid anhydride curing agents) are preferable from the viewpoint of heat resistance and transparency of the cured product. In addition, in the epoxy resin composition of this invention, a hardening | curing agent (E) can also be used individually by 1 type, and can also be used in combination of 2 or more type. Moreover, a commercial item can also be used as a hardening | curing agent (E). For example, commercially available acid anhydride-based curing agents include trade names “Licacid MH-700”, “Licacid MH-700F” (manufactured by Shin Nippon Rika Co., Ltd.); trade name “HN-5500” (Hitachi) Kasei Kogyo Co., Ltd.).

The content (blending amount) of the curing agent (E) in the epoxy resin composition of the present invention is not particularly limited, but is 50 to 200 with respect to 100 parts by weight of the total amount of the cationic curable compound contained in the epoxy resin composition. Part by weight is preferred, more preferably 80 to 150 parts by weight. More specifically, when acid anhydrides are used as the curing agent (E), cationic polymerization in all cationic polymerizable compounds (for example, compounds having an epoxy group) contained in the epoxy resin composition of the present invention. It is preferably used at a ratio of 0.5 to 1.5 equivalents per equivalent of a group (for example, epoxy group). By making content of a hardening | curing agent (E) into 50 weight part or more, it can fully harden | cure and there exists a tendency for the toughness of hardened | cured material to improve more. On the other hand, when the content of the curing agent (E) is 200 parts by weight or less, coloring of the cured product tends to be suppressed and the hue tends to be further improved.

[Curing accelerator (F)]
When the epoxy resin composition of the present invention contains a curing agent (E), it is preferable to further contain a curing accelerator (F). The curing accelerator (F) is a compound having a function of accelerating the reaction rate when a cationic curable compound (particularly a compound having an epoxy group) reacts with the curing agent (E). As the curing accelerator (F), a known or conventional curing accelerator can be used. For example, 1,8-diazabicyclo [5.4.0] undecene-7 (DBU) or a salt thereof (for example, phenol) Salt, octylate, p-toluenesulfonate, formate, tetraphenylborate, etc.); 1,5-diazabicyclo [4.3.0] nonene-5 (DBN) or a salt thereof (eg, phenol salt, Octylate, p-toluenesulfonate, formate, tetraphenylborate, etc.); tertiary such as benzyldimethylamine, 2,4,6-tris (dimethylaminomethyl) phenol, N, N-dimethylcyclohexylamine Amines; imidazoles such as 2-ethyl-4-methylimidazole and 1-cyanoethyl-2-ethyl-4-methylimidazole; Acid esters; phosphines such as triphenylphosphine and tris (dimethoxy) phosphine; phosphonium compounds such as tetraphenylphosphonium tetra (p-tolyl) borate; organometallic salts such as zinc octylate, tin octylate and zinc stearate; aluminum And metal chelates such as acetylacetone complex. A hardening accelerator (F) can also be used individually by 1 type, and can also be used in combination of 2 or more type.

Further, as the curing accelerator (F), trade names “U-CAT SA 506”, “U-CAT SA 102”, “U-CAT 5003”, “U-CAT 18X”, “U-CAT 12XD” ( (Developed product) (San Apro Co., Ltd.); Trade names “TPP-K”, “TPP-MK” (Hokuko Chemical Co., Ltd.); Trade name “PX-4ET” (Nippon Chemical Industry ( It is also possible to use a commercial product such as a product manufactured by Co., Ltd.

The content (blending amount) of the curing accelerator (F) in the epoxy resin composition of the present invention is not particularly limited, but is 0.1% relative to 100 parts by weight of the total amount of the cationic curable compound contained in the epoxy resin composition. The amount is preferably 01 to 5 parts by weight, more preferably 0.03 to 3 parts by weight, still more preferably 0.03 to 2 parts by weight. By setting the content of the curing accelerator (F) to 0.01 parts by weight or more, a sufficient curing accelerating effect tends to be obtained. On the other hand, when the content of the curing accelerator (F) is 5 parts by weight or less, coloring of the cured product tends to be suppressed and the hue tends to be improved.

[Additive]
In addition to the above, the epoxy resin composition of the present invention may contain various additives within a range not impairing the effects of the present invention. For example, when a compound having a hydroxyl group such as ethylene glycol, diethylene glycol, propylene glycol, or glycerin is included as the additive, the reaction can be allowed to proceed slowly. Other silane coupling agents such as silicone-based and fluorine-based antifoaming agents, leveling agents, γ-glycidoxypropyltrimethoxysilane and 3-mercaptopropyltrimethoxysilane as long as the viscosity and transparency are not impaired. , Surfactants, inorganic fillers such as silica and alumina, flame retardants, colorants, antioxidants, ultraviolet absorbers, ion adsorbers, pigments, phosphors (eg, YAG phosphor fine particles, silicate phosphors) Conventional additives such as fine inorganic particles such as fine particles), release agents, solvents (for example, γ-butyrolactone, etc.), thickeners, stabilizers, and the like can be used.

The epoxy resin composition of the present invention may further contain a compound having one or more oxetanyl groups in the molecule (sometimes referred to as “oxetane compound”). When the oxetane compound is included, various effects such as an effect of increasing the curing rate, an effect of increasing the conversion rate and the degree of polymerization, and an effect of improving the heat resistance and breaking strength of the cured product tend to be obtained. The oxetane compound may be a known or commonly used oxetane compound, and is not particularly limited. For example, 3,3-bis (vinyloxymethyl) oxetane, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, 3-ethyl-3- (hydroxymethyl) oxetane, 3-ethyl-3-[(phenoxy) methyl] oxetane, 3-ethyl-3- (hexyloxymethyl) oxetane, 3-ethyl-3- (chloromethyl) oxetane 3,3-bis (chloromethyl) oxetane, bis {[1-ethyl (3-oxetanyl)] methyl} ether, 4,4′-bis [(3-ethyl-3-oxetanyl) methoxymethyl] bicyclohexyl, 1,4-bis [(3-ethyl-3-oxetanyl) methoxymethyl] cyclohexane, 1,4 -Bis {[(3-ethyl-3-oxetanyl) methoxy] methyl} benzene, 3-ethyl-3-{[(3-ethyloxetane-3-yl) methoxy] methyl} oxetane, and the like. In addition, an oxetane compound can also be used individually by 1 type, and can also be used in combination of 2 or more type.

The epoxy resin composition of the present invention is not particularly limited, but can be prepared by stirring and mixing each of the above-described components as necessary. In addition, the epoxy resin composition of the present invention can be used as a one-component composition in which each component is mixed in advance, for example, two or more components prepared separately are used before use. It can also be used as a multi-component (for example, two-component) composition used by mixing at a predetermined ratio. The stirring / mixing method is not particularly limited, and for example, known or conventional stirring / mixing means such as various mixers such as a dissolver and a homogenizer, a kneader, a roll, a bead mill, and a self-revolving stirrer can be used. Further, after stirring and mixing, defoaming may be performed under vacuum.

The epoxy resin composition of the present invention is preferably liquid at 25 ° C. The viscosity (25 ° C.) of the epoxy resin composition of the present invention is not particularly limited, but is preferably less than 25000 Pa · s, more preferably less than 10,000 Pa · s, still more preferably 500 to 50000 mPa · s, and particularly preferably 2000 to 30000 mPa. -S. By setting the viscosity at 25 ° C. to less than 25000 Pa · s, the range of applicable molding methods tends to be expanded.

The epoxy resin composition of the present invention is preferably liquid at 30 ° C. The viscosity (30 ° C.) of the epoxy resin composition of the present invention is not particularly limited, but is preferably less than 10,000 Pa · s, more preferably 500 to 50000 mPa · s, and further preferably 2000 to 30000 mPa · s. By setting the viscosity at 30 ° C. to less than 10,000 Pa · s, the range of applicable molding methods tends to be expanded. The viscosity of the epoxy resin composition at 30 ° C. and 25 ° C. is determined using, for example, a digital viscometer (model number “DVU-EII type”, manufactured by Tokimec Co., Ltd.), rotor: standard 1 ° 34 ′ × R24, The temperature can be measured under the conditions of 25 ° C. or 30 ° C., and the rotational speed: 0.5 to 10 rpm. In addition, when the epoxy resin composition of the present invention is solid at 25 ° C. or solid at 30 ° C., for example, a cured product or a cured product by a molding method (for example, transfer molding method) in which heat is applied to melt A molded body of a fiber reinforced composite material can be obtained.

<Fiber reinforced composite material>
As described above, the epoxy resin composition of the present invention can be easily controlled in properties and viscosity, can be cured at a low temperature in a short time, and is further heat resistant by curing the epoxy resin composition. Resin composition for forming a composite material (fiber reinforced composite material) of the cured product and reinforcing fibers (resin composition for fiber reinforced composite materials) Can be preferably used. Specifically, by curing a prepreg obtained by impregnating or coating a reinforcing fiber with the epoxy resin composition of the present invention (sometimes referred to as “the prepreg of the present invention”), a fiber-reinforced composite material (“ May be referred to as “the fiber-reinforced composite material of the present invention”). Since the fiber-reinforced composite material of the present invention has the above configuration, it is excellent in productivity, heat resistance, and toughness.

As the reinforcing fiber, known or commonly used reinforcing fiber can be used, and is not particularly limited. For example, carbon fiber, glass fiber, aramid fiber, boron fiber, graphite fiber, silicon carbide fiber, high-strength polyethylene fiber, Examples thereof include tungsten carbide fibers and polyparaphenylene benzoxazole fibers (PBO fibers). Examples of the carbon fiber include polyacrylonitrile (PAN) -based carbon fiber, pitch-based carbon fiber, and vapor-grown carbon fiber. Of these, carbon fibers, glass fibers, and aramid fibers are preferable from the viewpoint of mechanical properties (toughness and the like), and carbon fibers are particularly preferable. That is, the epoxy resin composition of the present invention can be preferably used particularly as a resin composition (resin composition for carbon fiber reinforced composite material) for forming a carbon fiber reinforced composite material. In addition, the said reinforced fiber can also be used individually by 1 type, and can also be used in combination of 2 or more type.

The form of the reinforcing fiber is not particularly limited, and examples thereof include a filament (long fiber) form, a tow form, a unidirectional material form in which tows are arranged in one direction, a woven form, and a non-woven form. It is done. Examples of reinforced fiber fabrics include stitches that prevent unraveling sheets that are aligned in one direction, such as plain weave, twill weave, satin weave, or non-crimp fabric, or sheets that are laminated at different angles. Stitched sheets and the like.

The content of reinforcing fiber in the prepreg of the present invention is not particularly limited and can be adjusted as appropriate.

The method for impregnating or coating the reinforcing fiber with the epoxy resin composition of the present invention is not particularly limited, and can be carried out by an impregnation or coating method in a known or commonly used prepreg manufacturing method.

The prepreg of the present invention is obtained by impregnating or coating the reinforcing resin with the epoxy resin composition of the present invention, and further performing heating, active energy ray irradiation, etc. A cyclic epoxy compound (A), at least one compound (B) selected from the group consisting of a lactone addition compound (B1) having a hydroxyl group and a polycarbonate polyol (B2), and a polyvinyl acetal resin (C)). It may be a partially reacted product (that is, a semi-cured product).

As described above, the fiber-reinforced composite material of the present invention can be obtained by curing the prepreg of the present invention, and its production method is not particularly limited, but known or conventional methods such as a hand layup method, It can be produced by a prepreg method, RTM method, SMC molding method, pultrusion method, filament winding method, spray-up method, pultrusion method and the like. That is, as the fiber reinforced composite material of the present invention, a material molded by the prepreg method, a material molded by the RTM method, a material molded by the SMC molding method (for example, C-SMC; Carbon-fiber-reinforced Sheet Molding Compound).

The fiber-reinforced composite material of the present invention can be used as a material for various structures, and is not particularly limited. For example, an aircraft fuselage, main wing, tail wing, moving wing, fairing, cowl, door, etc .; Motor case, main wing, etc .; satellite structure; automobile parts such as automobile chassis; railway car structure; bicycle structure; ship structure; wind power blade; pressure vessel; fishing rod; tennis racket; Arm: It can be preferably used as a material for a structure such as a cable (for example, a cable core). The fiber-reinforced composite material of the present invention can also be preferably used as a constituent material for high-pressure tanks such as hydrogen tanks and liquefied natural gas (LNG) tanks.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Example 1
As shown in Table 1, 100 parts by weight of an alicyclic epoxy compound (trade name “Celoxide 2021P”, manufactured by Daicel Corporation), polyester polyol (trade name “Placcel 305”, polycaprolactone triol, manufactured by Daicel Corporation) 30 parts by weight, 7 parts by weight of polyvinyl acetal resin (trade name “Vinylec C”, manufactured by JNC Corporation), and 1 part by weight of thickening inhibitor (trade name “ADK STAB PEP-36”, manufactured by ADEKA Corporation) Stir into a flask, mix by heating and stirring at 100 ° C. for 2 hours, return to room temperature, and then 1.00 parts by weight of curing catalyst (trade name “Sun-Aid SI-100L”, manufactured by Sanshin Chemical Industry Co., Ltd.) And 0.035 parts by weight of a stabilizer (trade name “Sun-Aid SI Auxiliary Agent”, manufactured by Sanshin Chemical Industry Co., Ltd.) Taken Rentaro ", using Ltd. Thinky), it was mixed with stirring at room temperature for 5 minutes to prepare an epoxy resin composition. The viscosity at 30 ° C. and 25 ° C. of the obtained epoxy resin composition was measured by the method described above.
Next, the epoxy resin composition obtained above was put into a mold (a casting mold having a thickness of 4 mm and 0.5 mm) and heated at 80 ° C. for 4 hours as shown in Table 1, followed by A cured product was prepared by heating at 110 ° C. for 2 hours.

Examples 2 to 9, Comparative Examples 1 to 3
An epoxy resin composition was prepared in the same manner as in Example 1 except that the constituent components and blending ratio of the epoxy resin composition were changed as shown in Table 1.
Next, the cured product was prepared by putting the epoxy resin composition obtained above into a molding die (a casting mold having a thickness of 4 mm and 0.5 mm) and heating under the curing conditions shown in Table 1. .

[Evaluation]
The following evaluation was implemented about the cured | curing material obtained by the Example and the comparative example, and the epoxy resin composition before hardening.

(1) Tensile properties (tensile breaking strength, tensile modulus, tensile breaking elongation)
The cured products (thickness 4 mm) obtained in the examples and comparative examples were processed to prepare test pieces having a size of 4 mm thickness × 10 mm width × 80 mm length. Using the Tensilon Universal Material Testing Machine (manufactured by Orientec Co., Ltd.), the above test piece was subjected to a tensile test [tensile speed: 5 mm / min, load FS: 5 kN, chuck distance (in accordance with JIS K7161). (Distance between marked lines): 50 mm], and the tensile strength at break, tensile elastic modulus, and tensile elongation at break of the cured product were measured. The results are shown in the column of “Tensile properties” in Table 1, respectively.

(2) Heat resistance (DMA)
From the cured products (thickness 0.5 mm) obtained in the examples and comparative examples, a test piece having a size of 0.5 mm thickness × 8 mm width × 40 mm length was cut out, and a dynamic viscoelasticity measuring apparatus (DMA) ( The peak top temperature (Tg (tan δ) (glass transition temperature), unit: ° C.) of the loss tangent (tan δ) of the test piece was measured using Seiko Instruments Inc. The measurement was performed under the conditions of a measurement temperature range: −50 to 300 ° C., a heating rate: 3 ° C./min, and a deformation mode: a tensile mode under a nitrogen stream. The results are shown in the column of “Heat resistance (DMA)” in Table 1. Two values described as the glass transition temperature indicate that there are two peaks indicating the glass transition temperature in the above measurement.

(3) Pot Life From the viscosity (V1) at 25 ° C. of the epoxy resin compositions obtained in Examples and Comparative Examples, and the viscosity (V2) at 25 ° C. after leaving the epoxy resin composition at 23 ° C. for 14 days The viscosity change rate was calculated according to the following formula. The results are shown in the “pot life” column of Table 1. It means that the pot life of an epoxy resin composition is so long that a viscosity change rate is small. In addition, when the viscosity (V2) at 25 ° C. after being allowed to stand at 23 ° C. for 14 days becomes too high to be measured, and the rate of change in viscosity could not be calculated, “Measurement” in the “Pot Life” column of Table 1 "Not possible".
Viscosity change rate (%) = {(V2−V1) / V1} × 100

(4) Gel time Using the epoxy resin compositions obtained in Examples and Comparative Examples, a gel time tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd.), rotor: diameter φ5 × 110 mm, test tube: outer diameter φ12 × 90 mm, Oil: Measured under the condition of SRX310 (heated to 120 ° C.), and the time when the sample gelled (the time when the magnet fixing the rotor was removed due to thickening) was defined as the gel time. The results are shown in the “gel time” column of Table 1.

As shown in Table 1, the epoxy resin compositions obtained in the examples were able to form a cured product by curing at a low temperature in a short time. Moreover, the epoxy resin composition obtained in the Example had a small viscosity change rate and had a long pot life. Furthermore, the cured product of the epoxy resin composition obtained in the examples was excellent in mechanical properties such as tensile properties, and had high heat resistance (glass transition temperature and thermal decomposition temperature). On the other hand, the epoxy resin composition obtained in the comparative example was inferior in each characteristic such as extremely short pot life, low tensile elongation at break and low heat resistance.

In addition, the component used by the Example and the comparative example is as follows.
[Alicyclic epoxy compounds]
Celoxide 2021P: 3,4-epoxycyclohexylmethyl (3,4-epoxy) cyclohexanecarboxylate, manufactured by Daicel Corporation [lactone addition compound having a hydroxyl group (polyester polyol)]
PLACCEL 305: Polycaprolactone triol, manufactured by Daicel Corporation PLACCEL 205: Polycaprolactone diol, manufactured by Daicel Corporation PLACCEL 405D: Polycaprolactone tetraol, manufactured by Daicel Corporation [polyvinyl acetal resin]
Vinylec C: Carboxyl group-introduced polyvinyl formal resin, manufactured by JNC Corporation Vinylec PVF-L: Polyvinyl formal resin, manufactured by JNC Corporation [Thickening inhibitor]
ADK STAB PEP-36: Bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, manufactured by ADEKA Corporation [curing catalyst]
Sun-Aid SI-100L: Curing catalyst, manufactured by Sanshin Chemical Industry Co., Ltd. [Stabilizer]
Sun-Aid SI Auxiliary Agent: Aromatic Compound, Sanshin Chemical Industry Co., Ltd.

The epoxy resin composition of the present invention can be preferably used as a resin composition for fiber reinforced composite materials. By using the resin composition for fiber-reinforced composite material of the present invention, a fiber-reinforced composite material can be obtained. The fiber-reinforced composite material is, for example, an aircraft fuselage, main wing, tail wing, moving wing, fairing, cowl, door, etc .; spacecraft motor case, main wing, etc .; satellite structure; automobile parts such as automobile chassis; Rail vehicle structure; bicycle structure; ship structure; wind power blade; pressure vessel; fishing rod; tennis racket; golf shaft; robot arm; cable (for example, cable core material, etc.) Can be used. The fiber-reinforced composite material of the present invention can also be preferably used as a constituent material for high-pressure tanks such as hydrogen tanks and liquefied natural gas (LNG) tanks.

Claims (7)

1. Including at least one compound (B) selected from the group consisting of an alicyclic epoxy compound (A), a lactone addition compound (B1) having a hydroxyl group and a polycarbonate polyol (B2), and a polyvinyl acetal resin (C) An epoxy resin composition characterized by that.
2. The epoxy resin composition according to claim 1, wherein the content of the compound (B) is 5 to 60 parts by weight with respect to 100 parts by weight of the alicyclic epoxy compound (A).
3. The epoxy resin composition according to claim 1 or 2, further comprising a curing catalyst (D).
4. The epoxy resin composition according to any one of claims 1 to 3, which is a resin composition for fiber-reinforced composite materials.
5. A cured product obtained by curing the epoxy resin composition according to any one of claims 1 to 4.
6. A prepreg obtained by impregnating or coating a reinforcing fiber with the epoxy resin composition according to any one of claims 1 to 4.
7. A fiber-reinforced composite material obtained by curing the prepreg according to claim 6.