PROCESSES FOR PRODUCING FLAMEPROOF FIBER AND CARBON FIBER

摘要

A process for producing flameproof fibers by subjecting polyacrylic precursor fibers to flameproofing in an oxidizing atmosphere. The process for flameproof-fiber production includes a pretreatment for flameproofing, the pretreatment comprising: shrinking the precursor fibers under conditions of a temperature in the range of 220-260°C and a load of 0.58 g/tex or lower so that the precursor fibers come to have a degree of cyclization (I1620/I2240) not higher than 7%; and then conducting initial stretching at a load of 2.7-3.5 g/tex in a 230-260°C oxidizing atmosphere so that the fibers come to have a degree of cyclization not higher than 27% and a density not higher than 1.2 g/cm3. The fibers pretreated are successively subjected to ordinary flameproofing to produce flameproof fibers. By successively carbonizing the flameproof fibers, high-strength high-elasticity carbon fibers are obtained which are suitable for use in a composite material having high composite performance.