METHOD FOR PREPARING RAW MATERIAL FOR PITCH CARBON FIBER

摘要

PURPOSE:To obtain raw material pitch for melt spinning, which has an extremely low insoluble matter content, by subjecting a raw material pitch from which low-boiling matters have been removed to a thermal reaction treatment at a specified raw material pitch flow rate in a reactor having a specified inner diameter and a head difference. CONSTITUTION:A raw material pitch from which low-boiling matters have been removed is subjected to a thermal reaction treatment in an inert gas stream at a flow rate of F (l/min) in a reactor having an inner diameter D (mm.) and a head difference L (mm.) to prepare pitch as a raw material for the melt spinning of pitch carbon fiber. Said thermal reaction treatment is carried out in the range of L/F of 23-26, when a reactor having a L/D ratio of 1.2-2.5 is used. Pref. naphtha-cracked pitch is used as the raw pitch and the thermal reaction treatment is carried out at 355-390 deg.C. When L/F is in the range of 23-46, the flow rate of the inert gas used for the thermal reaction treatment is greatly increased and the thermal reaction can be terminated in a short time.