Toray Industries, Inc.

Sanyo Chemical Industries, Ltd.

Itsuki Taniguchi

Shigehiro Ohuchi

Ryuichi Itoh

Toshihiro Iwatsuki

Atsushi Sumida

Motoi Itoh

Toyokazu Minakuchi

Manabu Saito

Hiroshi Hasegawa

A sizing agent for carbon fibers which comprises, as the indispensable ingredients, an epoxy resin having a viscosity of more than 1,000 P but up to 20,000 P at 50 .degree. C. and a urethane compound prepared from a polyol having an oxyalkylene unit with a polyisocyanate.

Sizing agent for carbon fiber and carbon fiber treated with said sizing

Disclosed are reinforcing fibers, particularly carbon fibers, used for the manufacture of a reinforced plastic composite material which are surface-treated with a resinous composition comprising (A) epoxy resin, (B) condensation product of an acid component comprising unsaturated dibasic acid and a hydroxyl component comprising oxyalkylated bisphenol, and (C) oxyalkylene derivative of phenol. The resinous composition has good dispersibility in water, and the reinforcing fibers surface-treated therewith exhibit improved adhesion to various resin matrixes.

Resinous composition for surface-treating reinforcing fibers and

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Kyoto, Japan

Itsuki Taniguchi