| 摘要 |
PROBLEM TO BE SOLVED: To efficiently and stably produce a polyamide having a low content of cyclic oligomers. SOLUTION: The method for producing the polyamide is a method for producing a polyamide mainly consisting of capramide units and comprises subjecting an aqueous caprolactam solution of a water content of 2-20 wt.% to polymerization while feeding the solution to a normal pressure polymerization apparatus to form a thin film of the solution at the upper part of the apparatus. Alternatively, the method comprises subjecting a polyamide prepolymer of an amino group content of 0.03 mmol/1 g or more and a cyclic oligomer content of 0.6 wt.% or less obtained by heating an aqueous caprolactam solution of a water content of 2-20 wt.% at 200-330°C under the elevated pressure for 1-60 min to polymerization while feeding it to a normal pressure polymerization apparatus to form a thin film of the solution at the upper part of the apparatus. COPYRIGHT: (C)2009,JPO&INPIT
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