| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for efficiently producing a polyamide, with which adhesion of an oligomer and a low-molecular compound to an exhaust line, etc., under pressure to practically advance polymerization is controlled as much as possible when a polyamide is produced by melt polymerization using a batch type polymerizer. SOLUTION: The method for producing a polyamide comprises dripping a diamine to a dicarboxylic acid melted by heating under pressure or normal pressure to carry out melt polymerization, at a stage where the number-average molecular weight of a polyamide reaches at least≥6,000, changing a reaction pressure to a reduced pressure and further carrying out polymerization. The reaction pressure after the pressure change is in a specific pressure range. COPYRIGHT: (C)2005,JPO&NCIPI
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