Process for the manufacture of carbon fibers

Claim 1

In a process for producing fibers or filaments of carbon comprising melt spinning a carbonaceous material to form a spun fiber or filament, oxidizing the spun fiber or filament of said carbonaceous material at a temperature below that at which is softens and for a length of time necessary to render it infusible thereby stabilizing said fiber or filament and carbonizing the stabilized fiber or filament, the improvements comprising (a) employing as the carbonaceous material a filtered solution or extract of coal, said solution or extract of coal being formed by contacting and dissolving or extracting coal with a solvent boiling at above 200°C. which dissolves or extracts soluble or solubilizable aromatic constituents of coal to form a solution or extract of coal, filtering the solution or extract of coal and concentrating said solution or extract of coal to produce a filtrate containing 40-60% solvent and (b) as the step of oxidizing the spun fiber or filament, oxidizing the spun fiber or filament with air or oxygen at a heating rate of at least about 1°C/min., whereby said fiber or filament is stabilized to further heat treatment, said heat treatment including said step of carbonizing said stabilized fiber or filament.