Abstract: The present invention discloses: a composition comprising (A) an epoxy group-containing vinyl ester resin having, in the molecule, 0.8 to 0.3 equivalent of epoxy group and 0.2 to 0.7 equivalent of an ethylenically unsaturated group, (B) a radical-polymerizable monomer, (C) a curing agent, and (D) a carbon fiber impregnated with 0.5 to 5% by mass of (d) a vinyl ester resin as a sizing agent, obtained by an addition reaction of an epoxy resin and an ethylenically unsaturated carboxylic acid, and a carbon fiber-reinforced resin composite material produced by curing the above composition.

Abstract: A sizing agent for carbon fiber consisting of a reaction products containing an unsaturated urethane compound as the principal component obtained by reacting an unsaturated alcohol with an isocyanate compound is disclosed in claim 1.

Abstract: A process for producing a carbon fiber sheet, which comprises allowing, as necessary, an oxidized polyacrylonitrile fiber sheet to contain 0.2 to 5% by mass of a resin, then subjecting the resin-containing oxidized polyacrylonitrile fiber sheet to a compression treatment in the thickness direction under the conditions of 150 to 300° C. and 5 to 100 MPa (10 to 100 MPa when no resin treatment is made) to obtain a compressed, oxidized fiber sheet having a bulk density of 0.40 to 0.80 g/cm3 and a compression ratio of 40 to 75%, and thereafter subjecting the compressed, oxidized fiber sheet to a carbonizing treatment, which carbon fiber sheet has a thickness of 0.15 to 1.0 mm, a bulk density of 0.15 to 0.45 g/cm3, a carbon fiber content of 95% by mass or more, a compression deformation ratio of 10 to 35%, an electric resistance of 6 m&OHgr; or less and a feeling of 5 to 70 g.

Abstract: The invention provides a production method capable of reducing the amount of the chemical liquid (hydrazine and sodium carbonate, etc.) for applying a crosslinking treatment and a hydrolytic treatment, capable of shortening the treatment time, and capable of obtaining crosslinked acrylic moisture absorbing fibers having a sufficient moisture absorbing-moisture releasing performance and provides crosslinked acrylic moisture absorbing fibers. In the case of producing the crosslinked acrylic moisture absorbing fibers by applying a crosslinking treatment and a hydrolytic treatment to acrylic fibers, acrylic fibers made of a copolymer containing from 1 to 5% by weight a comonomer having an acidic group as a comonomer component are used as the raw material fibers to be treated.

Abstract: A phenol resin-impregnated sheet formed by impregnating a porous resin sheet with a phenol resin having a degree of cure of from 70% to 95% is arranged on and lamininated to the surface of a carbon fiber-reinforced thermosetting resin sheet. The thickness of the phenol resin impregnated sheet is between 0.01 mm and 1.0 mm. A very even, strong and water-proof wood reinforcing material is obtained. The wood reinforcing material is intergrated and cured on the surface of the wood material by the phenol resin-impregnated sheet to reinforce wood material (single board or bonded board) to form a reinforced wood material. The wood reinforcing material adheres suitably with the wood material and does not cause environmental contamination.