Provided is an epoxy resin composition that can achieve excellent low dielectric characteristics and high adhesive strength to metal. Specifically, provided is an epoxy resin composition comprising organic fine particles and an epoxy resin having a specific structure.

A resinous polymer compound used as a durable surface coating that maximizes content of epoxidized soybean oil (“ESO”) in lieu of bisphenol-A epoxy and hydrogenated bisphenol-A epoxy at various proportions to produce a less brittle, more elastic (flexible) film that, at various weight-percentages of substitution, presents a rapid enough reaction rate for efficient commercial production and yields a colorless and transparent film while lessening the amount of synthetic, petroleum-derived ingredients.

A resinous polymer compound used as a durable surface coating that maximizes content of epoxidized soybean oil (“ESO”) in lieu of bisphenol-A epoxy and hydrogenated bisphenol-A epoxy at various proportions to produce a less brittle, more elastic (flexible) film that, at various weight-percentages of substitution, presents a rapid enough reaction rate for efficient commercial production and yields a colorless and transparent film while lessening the amount of synthetic, petroleum-derived ingredients.

The present invention provides an epoxy resin composition containing:

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

##STR00001##

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].

The present invention provides a resin composition for a fiber-reinforced plastic, the resin composition including a cyanate ester (A), an epoxy resin (B), and an aromatic amine-based curing agent that is liquid at 25° C. (C), wherein the average number of cyanate groups in the cyanate ester (A) is 2.1 or greater, and/or the average number of epoxy groups in the epoxy resin (B) is 2.1 or greater. A fiber-reinforced plastic that is produced using this composition and a reinforcing fiber has favorable heat resistance and excellent tensile and bending properties, and therefore can be applied to a wide variety of fields including transport vehicles such as ships, automobiles, and aircrafts, sporting goods, building materials such as sinks and window frames, as well as industrial machinery and materials such as high-pressure gas tanks and blades for wind power generation.

A flux resin composition includes an epoxy resin, an imidazole compound, a thixo agent, and an activator. The epoxy resin includes at least one resin selected from the group consisting of naphthalene epoxy resins, biphenyl aralkyl epoxy resins, trisphenol methane epoxy resins, biphenyl epoxy resins, and dicyclopentadiene epoxy resins. The content of the at least one resin is equal to or greater than 20% by weight with respect to a total weight of the epoxy resin.

A flux resin composition includes an epoxy resin, an imidazole compound, a thixo agent, and an activator. The epoxy resin includes at least one resin selected from the group consisting of naphthalene epoxy resins, biphenyl aralkyl epoxy resins, trisphenol methane epoxy resins, biphenyl epoxy resins, and dicyclopentadiene epoxy resins. The content of the at least one resin is equal to or greater than 20% by weight with respect to a total weight of the epoxy resin.

An epoxy resin composition suitable for molding a fiber-reinforced plastic molded article is provided. The molded article has exceptional mechanical properties. In particular, a tubular molded article has high breaking strength. The epoxy resin composition contains components (A), (C), and (D), where component (A) is an epoxy resin of a particular formula, component (C) is an epoxy resin other than component (A) that is liquid at 25° C., and component (D) is a curing agent.

A copolymer is formed by reacting a composition I, which includes (a) a first epoxy compound having a chemical structure of

##STR00001##

wherein R.sup.1 is single bond, —O—,

##STR00002##

(b) a second epoxy compound that is different from (a) the first epoxy compound, and (c) a curing agent. The copolymer can be mixed with inorganic powder to form a composite material.

The present invention disclosed novel epoxy novolac composite comprising environmentally friendly toughening agents based on bio-derived chemicals namely, Difunctional glycidyl ether epoxy resin (Cardolite NC-514) and Polyglycidyl ether of an alkenyl phenol formaldehyde novolac resin (Cardolite NC-547) used for the toughening of epoxy novolac resin namely Poly[(phenyl glycidyl ether)-co-formaldehyde] [PPGEF].