PROCESS FOR THE PREPARATION OF MESOPHASE PITCHES

A process for the preparation of an excellent mesophase pitch suitable for use as a spinning pitch for the production of high performance carbon fibers is disclosed. The mesophase pitch can satisfy the four remarkable characteristics at the same time, i.e., a softening point of below 320 DEG C as determined by Mettler method, a mesophase content of above 90% as examined on a polarized microscope, a quinoline insoluble content of less than 20%, and a xylene soluble content of less than 20%. The mesophase pitch is particularly homogeneous and is easily spinnable. The process can be characterized by a preliminary extraction step, a continuous heat treatment step, and an extraction step. In some cases, the preliminary extraction step can be omitted. Graphite fibers having a tensile strength of about 400 Kg/mm and a modulus of elasticity of above 60 ton/mm can be obtained from the mesophase pitch. Further, even carbon fibers prepared at a carbonization temperature of 1000 DEG C have a tensile strength of about 300 Kg/mm .