The purpose of the present invention is to provide: an epoxy resin composition which enables the achievement of a resin cured product that has high flame retardancy and excellent mechanical characteristics; and a prepreg and a fiber-reinforced composite material, each of which uses this epoxy resin composition. One embodiment of the epoxy resin composition according to the present invention, said epoxy resin composition having achieved the above-described purpose, contains the components (A) and (B) described below. (A): a bifunctional glycidyl amine type epoxy compound (B): an epoxy compound having a specific structure and/or an epoxy compound having another specific structure

A prepreg having excellent tackiness as well as excellent resin strength after curing and strength in the non-fiber direction is described; and a fiber-reinforced composite material using the prepreg, where the prepreg is composed of reinforcing fibers and a resin composition which includes [A] an epoxy resin, [B] a dicyanamide and [C] a compound having a melting point of 130° C. or lower and a solubility parameter whose difference from the solubility parameter of [B] is 8 or less.

A photobase generator, includes a compound including a first skeleton represented by the following formula (a); and a second skeleton including a nitrogen atom bonding to a bonding position of the first skeleton to form an amide group, and a pyridine skeleton in addition to the nitrogen atom, in which the compound generates a base in which a hydrogen atom is bonded with the nitrogen atom of the second skeleton by light irradiation. In formula (a), G is a divalent aromatic group, and * represents the bonding position with the nitrogen atom.

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Provided is a curative part usable in a two-part curable composition. The curative part includes a liquid amine; a heterogeneous dispersant; and core-shell rubber particles having an elastomeric core and a (meth)acrylic shell. The core-shell rubber particles and the heterogeneous dispersant can be collectively shear-dispersed in the liquid amine such that the core-shell rubber particles are substantially non-aggregated and the curative part is phase-stable over a period of at least 3 months at ambient temperature. Advantageously, large amounts of core-shell rubber particles can thus be incorporated into a cured resin matrix, which can afford significantly enhanced impact performance.

A curable composition comprising (A) an epoxy resin containing on average more than one epoxy group per molecule; (B) a compound of formula A[—X—CO—CH.sub.2—CN].sub.n(1), wherein A is hydrogen or C.sub.1-C.sub.12 alkyl which is unsubstituted or substituted by one or more C.sub.1-C.sub.12 alkoxy groups, C.sub.1-C.sub.12 alkylcarbonyl groups, C.sub.7-C.sub.25 arylcarbonyl groups, hydroxyl groups, amino groups, C.sub.1-C.sub.12 alkylamino groups, C.sub.1-C.sub.12 dialkylamino groups, cyano groups or halogen atoms, or A is a bivalent aliphatic, cycloaliphatic, aromatic, araliphatic or heterocyclic organic radical, X denotes —O—or —NR.sub.1—, wherein R.sub.1 is hydrogen or C.sub.1-C.sub.12 alkyl which is unsubstituted or substituted by one or more C.sub.1-C.sub.12 alkoxy groups, C.sub.1-C.sub.12 alkylcarbonyl groups, C.sub.7-C.sub.25 arylcarbonyl groups, hydroxyl groups, amino groups, C.sub.1-C.sub.12 alkylamino groups, C.sub.1-C.sub.12 dialkylamino groups, cyano groups or halogen atoms, n is 1 or 2; and (C) a protected base in the form of an adduct or salt which is able to release a basic compound upon heating to a temperature greater than 70° C., is storage-stable, allows processing over a longer period of time (pot-life) and produces cured products having outstanding mechanical and thermal properties.

The present invention provides an epoxy resin composition containing:

an epoxy resin [A] that is a compound represented by Chemical formula (1) shown below:

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wherein R.sub.1 to R.sub.4 each independently represent one selected from the group consisting of a hydrogen atom, an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, and a halogen atom, and X represents one selected from —CH.sub.2—, —O—, —S—, —CO—, —C(═O)O—, —O—C(═O)—, —NHCO—, —CONH—, and —SO.sub.2—;

a bifunctional epoxy resin [B] having an amine type glycidyl group;

a curing agent [C] containing an aromatic polyamine, and having at least one substituent selected from an aliphatic substituent, an aromatic substituent, and a halogen atom at an ortho position with respect to an amino group; and

a particulate rubber component [D].

It is to provide an epoxy resin comprising a phenol compound having a curing acceleration effect even when a low reactive curing agent is used, and allowing the amount of the curing agent used to be reduced. Here is used an epoxy resin composition comprising a glycidylamine-type epoxy resin, an aromatic polyamine and 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane. The aromatic polyamine and 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane optionally form a clathrate compound.

Provided is an epoxy resin composition with improved heat resistance and resin elongation. Further provided is a fiber-reinforced composite material which uses the epoxy resin composition and thereby excels in compression strength in high-temperature environments and interlaminar toughness. The epoxy resin composition comprises the constituents [A], [B] and [C], 8-40 mass % of [B] is contained in the epoxy resin composition. The number of moles of active hydrogen contained in [C] is 1.05-2.0 times the number of moles of epoxy groups contained in the entire epoxy resin composition, in a cured resin formed by curing the epoxy resin composition and having a degree of curing of at least 90% obtained by DSC (differential scanning catorimetry), [A], [B] and [C] form a monolayer structure, or a phase separation structure of less than 500 nm. The rubber state modulus of elasticity Y (MPa) and glass transition temperature X (° C.) obtained by DMA (dynamic mechanical analysis) of the cured resin satisfy formula (1). [A] amine type epoxy resin [B] thermoplastic resin [C] aromatic amine

0.19X/° C.-31.5≦Y/MPa≦0.19X/° C.-27   (1)

An epoxy resin composition is provided including at least the following component [A], component [B], and component [C] or [D] wherein cured product obtained by curing the epoxy resin composition has a rubbery state modulus in dynamic viscoelasticity evaluation of 10 MPa or less, and the cured product has a glass transition temperature of at least 95° C.; [A] an aromatic epoxy resin having a functionality of at least 3, [B] an aromatic diamine having a substituent at ortho position of each amino group or a cycloalkyldiamine wherein the carbon atom adjacent to the carbon atom bonded to each amino group has a substituent, [C] an aliphatic polyamine having an alkylene glycol structure, [D] a straight chain or branched aliphatic polyamine containing 6 to 12 carbon atoms.

To provide a curable resin composition, from which a cured product having high heat resistance, a low dielectric loss tangent, high adhesion to a conductor can be obtained. A dry film, a resin-clad copper foil, a cured product, and an electronic component containing the curable resin composition are to be provided. A curable resin composition containing (A) an epoxy resin and (B) a compound having an active ester group is obtained, which has ratio of the total amount of epoxy group(s) in (A) the epoxy resin/the total amount of active ester group(s) in (B) the compound having an active ester group in the composition in the range of 0.2 to 0.6. A dry film, a resin-clad copper foil, a cured product, and an electronic component containing the curable resin composition are also obtained.