| 摘要 |
PURPOSE:To provide the titled pitch high in the content of optically anisotropic phase, which specific molecular weight distribution, capable of stable melt spinning at low temperatures, enabling high tenacity-high modulus carbon fiber to be given and also obtainable at low cost and in high yield. CONSTITUTION:The objective pitch capable of melt spinning at adequately low temperatures, having the following characteristics: (1) content of optically anisotropic phase 80-100%, (2) softening point 230-320 deg.C, (3) number-average molecular weight 900-1,500, (4) fraction with a molecular weight <=600, 30-60mol%, (5) fraction with a molecular weight >=1,500, 15-35mol%, (6) fraction with a molecular weight 600-1,500, 20-50mol%, (7) maximum molecular weight <=30,000. For the production of this pitch, a tarry material with each non-saturated constituent having large fa-value and both number-average molecular weight and maximum molecular weight for each constituent being sufficiently small may be subjected to pyrolytic polycondensation at 400-440 deg.C for 1-4hr under ambient pressure and inert gas flow while removing low- molecular weight substances. |
