Nippon Steel Corporation

Nippon Steel Chemical Co., Ltd.

Nobuyuki Tsuji

Hiromi Kimura

Toshikazu Takeda

Kenji Kubomura

Michiya Hayashida

Kenji Kobomura

Hironori Maikuma

Hideo Osone

Mikio Shima

A pitch-based carbon fiber reinforced composite material is improved with regard to its compressive strength and compression strain at failure by combining polyacrylonitrile-based carbon fibers. The pitch-based carbon fibers have a modulus in tension of not less than 400 GPa, a tensile strength of not less than 2000 MPa, a compressive strength as a unidirectionally reinforced composite material of 100 MPa to 800 MPa and a fiber diameter of 4 .mu.m to 15 .mu.m and the polyacrylonitrile-based carbon fibers have a modulus in tension of not less than 200 GPa, a compressive strength and compression strain at failure as a unidirectionally reinforced composite material larger than those of the pitch-based carbon fibers, and a fiber diameter smaller than that of the pitch-based carbon fibers.

Unidirectional prepreg and carbon fiber reinforced composite materials

A process for producing a bicycle frame of a fiber-reinforced plastics (FRP) including the steps of: forming parts of a bicycle frame such as an upper pipe, a lower pipe, a vertical pipe, a chain stay and a rear fork, or a combination thereof, with an FRP; arranging the bicycle frame parts in a structure of the bicycle frame; forming, with an FRP, lug portions onto the arranged bicycle frame parts at a required position whereat the bicycle frame parts are to be connected and fixed to each other; and curing all of the lug portions at one time, to thereby simultaneously accomplish an assembling of the bicycle frame. A process for forming a lug portion of a FRP bicycle is disclosed which includes the steps of: providing a female mold with a cavity having a shape of a final lug portion; disposing a flexible sheet on a surface of the cavity; arranging frame parts in a structure of a bicycle frame; arranging the female mold at a lug portion of the arranged bicycle frame parts; supplying and foaming a foaming material in the female mold at the lug portion; removing the female mold to leave an assembly of the frame parts with a foamed body; removing the flexible sheet from the female mold; laminating a foaming sheet and then a prepreg of resin-impregnated continuous fibers onto the foamed body; arranging the female mold over the laminated prepreg; and heating to cure the resin while foaming the foaming sheet, to thereby form the lug portion of the FRP bicycle frame.

Process for producing a bicycle frame made of fiber-reinforced plastics

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Kawasaki, Japan

Nobuyuki Tsuji