Abstract: The present invention relates to a process for producing a carbon fiber chopped strand which comprises preparing a pitch fiber from petroleum pitch or coal pitch, cutting the pitch fiber to a predetermined desired length, heating the cut pitch fiber at a high density accumulation in the atmosphere of an oxidative gas to infusibilize the cut pitch fiber, and then carbonizing and graphitizing the infusibilized fiber in an inert atmosphere. According to the process of the invention, no fuzz are formed on the fiber and no uneven infusibilization takes place. Further, the pitch fiber chopped strand accumulation has a high bulk density and relieve exothermic excursion naturally, and therefore neither combustion nor sticking takes place even in an oxidative atmosphere. Accordingly, the production speed can be enhanced and the cost can be lowered to a great extent.

Abstract: Disclosed is a method for producing carbon fiber chopped strands excellent in bundling of fibers, high in bulk density, uniform in fiber length and superior in molding operability which includes application of an inorganic and/or organic binder in an amount of 0.1-3% by weight in terms of solid to carbon fiber or graphite fiber strands or chopped strands made from a petroleum or coal pitch.

Abstract: The present invention relates to a process for the infusibilization of pitch fiber which comprises, in the production of pitch type carbon fiber, attaching a powder of solid lubricant to a pitch fiber and then subjecting the pitch fiber to an infusibilizing treatment. According to the present invention, the use of oxidant used in prior processes can be excluded, the process can be operated with a high safety, and the period of time required for the infusibilization can be shortened. Further, the infusibilized fiber obtained according to the invention can directly be introduced into the carbonization process, without any particular washing treatment and the like.