| 摘要 |
PROBLEM TO BE SOLVED: To provide a carbon fiber which has excellent tensile elasticity and adhesion strength and exerts excellent mechanical strength in carbon fiber reinforced composite materials using the carbon fiber in a very small amount used.SOLUTION: A method of producing a carbon fiber bundle comprises: subjecting polyacrylonitrile based precursor fiber bundle to a flame resistance imparting treatment and preliminary carbonization to obtain a preliminarily carbonized fiber bundle; and carbonizing the preliminarily carbonized fiber bundle in an inert atmosphere of 1,200-2,000°C under a tensile force of 13-18 mN/dtex. The trial length dependency coefficient mof the bundle strength of the preliminarily carbonized fiber bundle during carbonization is 10-40, or the carbon fiber bundle has a crystallite size Lc (nm) of 1.7-5.6, a crystal orientation &pgr;(%) meeting the condition 3.1×Lc+82<&pgr;<3.1×Lc+83 and a trial length dependency coefficient mof the bundle strength of 12-40. |
