Abstract: Epoxy resin compositions comprising (a) an epoxy resin, (b) a latent curing agent with curing power at 100° C. or below and (c) an aromatic amine-based curing agent and/or an alicyclic amine-based curing agent, which are curable in two stages, or epoxy resin compositions further comprising (d) a curing accelerator, as well as a prepregs comprising reinforcing fiber materials impregnated with the epoxy resin compositions. The compositions give die-releasable cured products by primary curing at low temperature, give highly heat-resistant cured products by secondary curing, and exhibit satisfactory stability at room temperature.

Abstract: Epoxy resin compositions comprising (a) an epoxy resin, (b) a latent curing agent with curing power at 100° C. or below and (c) an aromatic amine-based curing agent and/or an alicyclic amine-based curing agent, which are curable in two stages, or epoxy resin compositions further comprising (d) a curing accelerator, as well as a prepregs comprising reinforcing fiber materials impregnated with the epoxy resin compositions. The compositions give die-releasable cured products by primary curing at low temperature, give highly heat-resistant cured products by secondary curing, and exhibit satisfactory stability at room temperature.

Abstract: The present invention relates to a repair and reinforcement method for preexisting structures such as buildings or the like, and in particular, relates to a repair and reinforcement method for concrete structures, and to an anisotropic textile employed in this method. The present invention provides a method which permits execution even in low temperature conditions, and which moreover exhibits superior repair and reinforcement effects in a short period of time; during the impregnation of a resin into a sheet material comprising reinforcement fibers and the curing of this resin to form a fiber-reinforced resin layer which is used in the repair and reinforcement of preexisting structures, a reactive mixture having a gelling period of 15 minutes or more at a temperature of 20° C. and which polymerizes even at 5° C.

Abstract: The present invention relates to a repair and reinforcement method for preexisting structures such as buildings or the like, and in particular, relates to a repair and reinforcement method for concrete structures, and to an anisotropic textile employed in this method. The present invention provides a method which permits execution even in low temperature conditions, and which moreover exhibits superior repair and reinforcement effects in a short period of time; during the impregnation of a resin into a sheet material comprising reinforcement fibers and the curing of this resin to form a fiber-reinforced resin layer which is used in the repair and reinforcement of preexisting structures, a reactive mixture having a gelling period of 15 minutes or more at a temperature of 25° C. and which polymerizes even at 5° C.

Abstract: A prepreg for fiber-reinforced composite materials comprising (A) a reinforcing fiber having a modulus of elasticity of 200 GPa or more, (B) a fibrous thermoplastic resin having a modulus of elasticity of 100 GPa or less, and (C) a thermosetting matrix resin. The prepreg of the present invention does not only have excellent handling property equivalent to that of the prepreg with the conventional thermosetting resin as a matrix, but also gives excellent toughness to the resulting molded product without injuring the thermal and mechanical properties. Particularly, it has a high resistance to interlaminar fracture when exposed to impact, so that it is preferably used as a structural material for airplanes, etc.

Abstract: A resin composition for composites which comprises as essential components(A) a three-bismaleimide mixture of N,N'-diphenylmethanebismaleimide, N,N'-tolylenebismaleimide, and N,N'-trimethylhexamethylenebismaleimide and(B) an allyl etherified substituted phenol novolak resin and/or allyl phenyl ether compound represented by the following general formula (I): ##STR1## wherein, X denotes a direct bond or the divalent radical --CH.sub.2 --, ##STR2## --O--, --S--, --SO.sub.2 --, ##STR3## or ##STR4## and R.sub.1 through R.sub.4 are the same or different in a molecule and denote each --CH.sub.3, --C.sub.2 H.sub.5, --CH(CH.sub.3).sub.2, --nC.sub.3 H.sub.7, --nC.sub.4 H.sub.9, --C(CH.sub.3).sub.3, ##STR5## --CH.sub.2 CH(CH.sub.3).sub.2, or --Br.

Abstract: A resin composition for composites which comprises as essential components(A) a three-bismaleimide mixture of N,N'-diphenyl-methanebismaleimide, N,N'-tolylenebismaleimide, and N,N'-trimethylhexamethylenebismaleimide and(B) an allyl etherified substituted phenol novolak resin and/or allyl phenyl ether compound represented by the following general formula (I): ##STR1## wherein, X denotes a direct bond or the divalent radical ##STR2## and R.sub.1 through R.sub.4 are the same or different in a molecule and denote each --CH.sub.3, --C.sub.2 H.sub.5, --CH(CH.sub.3).sub.2, --nC.sub.3 H.sub.7, --nC.sub.4 H.sub.9, --C(CH.sub.3).sub.3, ##STR3## --CH.sub.2 CH(CH.sub.3).sub.2, or --Br.

Abstract: An epoxy resin composition is disclosed that can be cured at a temperature of 150.degree. C. or below, and can be used to provide a high performance carbon fiber composite material having a 0.degree. direction bending strength of 220 kg/mm.sup.2 or over, and an interlayer shear strength of 10 kg/mm.sup.2 or over.The composition is made up of:(A) an epoxy compound containing 10 to 100% by weight of m- or o-methyl-p-N,N-diglycidyl-aminophenyl-ester or its oligomer,(B) diaminodiphenylsulfone and/or diaminodiphenylmethane,(C) dicyandiamide, 2,6-xylenylbiguanide, o-tolylbiguanide, diphenylguanidine, adipil dihydrazide, azelayl dihydrazide, or isophthalic acid dihydrazide, and(D) a urea compound.