| 摘要 |
PROBLEM TO BE SOLVED: To provide a method to obtain a polyacrylonitrile polymer solution with high quality and at a low cost, which has a specific molecular weight distribution required for the production of carbon fiber precursor fiber to give excellent spinning properties in a dry-moisture spinning method. SOLUTION: A method of manufacturing polyacrylonitrile polymer solution has 2 processes of polymerization, processes A and B. The process A includes obtaining a polymer solution containing polyacrylonitrile having a weight-average molecular weight Mw of 800,000-8,000,000 and unreacted acrylonitrile by heating and polymerizing a solution containing acrylonitrile and 0.001-0.09 mmol/L of polymerization initiator. The process B includes adding and heating the polymerization initiator in such an amount that the ratio (A/B) of the amount of polymerization initiator used in the process A to the amount of polymerization initiator used in the process B is 0.001-0.2, and a chain transfer agent to a polymer solution containing the unreacted acrylonitrile and polyacrylonitrile obtained in the process A, in the same polymerization tank as the one used in the process A, so that a weight-average molecular weight Mw of the polyacrylonitrile in the polymer solution is 100,000-700,000. According to this method of manufacturing the polyacrylonitrile polymer solution, the heating temperature and/or heating period of the process B is adjusted so that the amount of polymerization initiator left in the polymerization tank at the end of process B is 0-50% of the amount of polymerization initiator added in the process A. COPYRIGHT: (C)2011,JPO&INPIT |
