METHOD FOR PRODUCING A PRECURSOR PITCH FOR CARBON FIBER

摘要

KAWASAKI STEEL 58-38,182 Precursor pitch to be used for formation of carbon fiber is produced by heating a coal tar soft or middle pitch at a temperature of 350-500.degree.C at a first stage to form mesophase, extracting the thus treated pitch with a solvent, separating and removing the solvent insoluble portion including mesophase to obtain a pitch containing no free carbon and further at the second stage heat-treating the pitch containing no free carbon in an inert gas atmosphere under atmospheric pressure or a reduced pressure under the following condition 600-1.2 T ? 0 ? 1,800-3.6 T (provided that 350 ? T ? 500) wherein T(.degree.C) is the temperature of the heat treatment and .theta. (min) is the time for which said temperature is held, to form bulk mesophase pitch containing 20-60% by weight of quinoline insoluble portion.