Process for the preparation of carbon fibers having structure reflected in cross sectional view thereof as random mosaic

摘要

A process for preparing carbon fibers wherein carbon fibers are prepared from the mesophase-pitch containing not more than 80% by weight of a quinoline-insoluble component and showing, under a polarization microscope, more than 70% of optically anisotropic region, comprising the steps of subjecting a mesophase-pitch showing a viscosity of 10 to 100 poise at a temperature of spinning of 330 DEG to 450 DEG C., to rotating-centrifugal-spinning in a rotating-centrifugal spinning machine with a peripheral velocity of rotating nozzle thereof of 300 to 1000 m/min and exposing the thus spun fibers of the mesophase pitch to a flow of a gas spouting into a spinning direction at a temperature of 280 DEG to 400 DEG C. and at a linear velocity of 50 to 200 m/sec, thereby preparing carbon fibers showing a random-mosaic structural pattern in cross section thereof perpendicular to fiber axis.