Method of producing mesophase pitch type carbon fibers and nozzle for spinning same

摘要

In a method of producing mesophase pitch based carbon fibers, including the steps of melt-spinning a mesophase pitch through a nozzle (1) having at least one pair of a counter-bore (2) and a circular capillary (3) to form a pitch fiber and subjecting the pitch fiber to an infusible treatment, a carbonization treatment, and if necessary, a graphitization treatment, to form a carbon fiber, the nozzle has a degree of asymmetry phi of from 0.1 to 0.9, phi being defined by the following equation phi =SA/SB, wherein SA is an area of an inscribed circle in a contour of the cross-section of the counter-bore, which circles is perpendicular to the nozzle axis and has a center on the axis of the capillary and inscribed and SB is a total area of the cross-section of the counter-bore.