MANUFACTURE OF STAPLE SLIVER AND ROBBING OF OXIDATED POLYACRYLONITRILE FIBER

摘要

Staple fibre yarn is prepd. from oxidised polyacrylonitrate filaments for the subsequent prodn of high strength carbon fibres of high modulus. At least ne roving consisting of continuous filaments of oxidised polyacrylonitrile is converted to a staple yarn by first subjecting the roving to steam crimping and subsequent to extension breakage. These continuous filaments are oxidised as a roving under tension by heating this in the presence of oxygen for a length of time which is limited in such a way that the filaments remain sufficiently elastic to withstand the steam crimping step without disintegrating. The process permits the filaments to be oxidised in an untwisted state so that the oxidn. penetration is uniform, but the tensile strength of the roving is sufficient to withstand the shrinkage during such oxidn.