Baked pencil lead and method for manufacturing the same

摘要

Baked pencil leads are disclosed herein which are prepared by kneading, extruding and baking a composition containing a graphite as a filler and a binder, wherein a degree of orientation pi of the graphite in the direction of an extrusion axis measured by X-ray diffraction is 0.85 or more and the resultant leads have a flexural modulus of 100 GPa or more and a bending strength of 320 MPa or more. The baked pencil leads can be manufactured by carrying out the extrusion so that back face pressure just above an extrusion nozzle may be 300 kg/cm or more and a shear rate at a time when the molten kneaded composition passes through the nozzle may be 5x104 (1/sec) or more.