Importance

Loading Importance Indicators...

Abstract

The resent invention provides a carbon fiber which enables a molded article produced from a fiber-reinforced composite material using the carbon fiber to exhibit excellent flexibility and to be freed from defects such as bending. According to the method of the present invention the carbon fiber is produced by a two-stage infusibilizing process, namely carrying out a first-stage infusibilization of a pitch-based fiber, which is obtained from mesophase pitch having a softening point of 200 to 400.degree. C. and a true density of 1.30 to 1.38 g/cm.sup.3, in a mixed gas atmosphere having a nitrogen dioxide concentration of 1 to 5% by volume and an oxygen concentration of 5 to 50% by volume, the balance being an inert gas or steam, at a temperature between 100 and 200.degree. C. and then carrying out a second-stage infusibilization of the product of the first-stage infusibilization in a mixed gas atmosphere having a nitrogen dioxide concentration of 0.1 to 5% by volume and an oxygen concentration of 5 to 40% by volume, the balance being an inert gas or a mixture of the inert gas and steam, at a temperature between 200 and 350.degree. C.

Loading the Abstract Image...

First Claim