Process for producing conductive graphite fiber

Abstract

A process for producing a graphite fiber is disclosed, which is characterized by using, as a starting material, an optically anisotropic pitch prepared from a compound having a specific chemical structure as represented by formula (I) shown in the specification. The resulting graphite fiber shows a highly developed graphite structure and has excellent electrical conductivity.

What is claimed is: 
     
       1. A process for producing a graphite fiber which comprises melt-spinning an optically anisotropic pitch, making the resulting fiber infusible, carbonizing the infusible fiber, and graphitizing the carbonized fiber at a temperature of from 2500° to 3000° C., wherein said optically anisotropic pitch is prepared by heat treating a compound represented by formula (I): ##STR2## wherein R represents a hydrogen atom or a methyl group; and m represents an integer of 1 or more. 
     
     
       2. A process as claimed in claim 1, wherein said pitch has an optical anisotropy of at least 95%, a softening point of from 210° to 250° C., and a toluene insoluble content of 50% by weight or less. 
     
     
       3. A process as claimed in claim 1, wherein said graphite fiber has an interlaminar distance (d 002 ) of 3.370 Å or less as determined by X-ray diffractometry and a specific resistivity of from 60 to 200 μΩcm. 
     
     
       4. A process as claimed in claim 1, wherein said compound of formula (I) is a polymer obtained by polymerizing 1,2,4-trimethylbenzene or 1,3,5-trimethylbenzene and formaldehyde in the presence of a protonic acid as a catalyst, said polymer having an oxygen content of not more than 2% by weight, and said graphite fiber having a interlaminar distance (d 002 ) of 3.370 Å or less as determined by X-ray diffractometry and a specific resistivity of from 60 to 200 μΩcm.