METHOD FOR CONTINUOUSLY PRODUCING POLYAMIDE

PROBLEM TO BE SOLVED: To provide a method for continuously producing a polyamide with a stabilized polymerization degree and good quality. SOLUTION: The method for continuously producing the polyamide includes: (a) a raw material preparation step of individually melting a diamine and dicarboxylic acid, or producing a salt of the amine and carboxylic acid in water; (b) a raw material introduction step of continuously introducing raw materials into a tubular reaction apparatus; (c) an amidation step of passing the introduced raw materials through the tubular reaction apparatus, thereby effecting amidation to obtain a reaction mixture containing an amidated product and condensed water; (d) an initial polymerization step of introducing the reaction mixture into a continuous reaction apparatus of separation and removal of water, and increasing the polymerization degree while separating and removing the water at a temperature higher than a melting point of finally obtained polyamide to obtain a polyamide prepolymer; and (e) a final polymerization step of introducing the polyamide prepolymer into a continuous reaction apparatus of separation and removal of water, and further increasing the polymerization degree at a temperature higher than the melting point of the finally obtained polyamide to obtain a polyamide adjusted to desired relative viscosity [RV]. COPYRIGHT: (C)2010,JPO&INPIT