Patent ID: 7361618

Claim:
A prepreg, comprising a carbon fiber-made reinforcing woven fabric impregnated with 30 to 50 wt % of a resin, and having a cover factor of not less than 90%, wherein the carbon fiber-made reinforcing woven fabric comprises, warp yarns each of which comprises carbon fibers and weft yarns each of which comprises carbon fibers, and auxiliary yarns each of which comprises a glass fiber yarn and arranged along at least either the warp yarns comprising the carbon fibers, as warp-oriented auxiliary yarns or the weft yarns comprising the carbon fibers, as weft-oriented auxiliary yarns, wherein each of the warp-oriented auxiliary yarns or the weft-oriented auxiliary yarns is arranged in an up and down pattern of passing over and under the weft yarns or the warp yarns, respectively, at an up/down frequency such that an up/down frequency of a selected warp-oriented auxiliary yarn with respect to the weft yarns is different from that of an adjacent warp yarn or an un/down frequency of a selected weft-oriented auxiliary yarn with respect to the warp yarns is different from that of an adjacent weft yarn, and wherein each of the auxiliary yarns is arranged between the warp yarns adjacent each other or the weft yarns adjacent each other, and wherein the respective fineness of each of the warp yarns and each of the weft yarns are in a range from 3,000 to 90,000 deniers, and the glass fiber yam has a fineness of not more than 500 denier.