Process for preparing polyamide.

摘要

A process for preparing a polyamide is provided. The polyamide is prepared by causing a dicarboxylic acid and a diamine to polycondensate directly under an atmosphere of an inert gas at atmospheric pressure. The polycondensation reaction is mainly carried out in two diamine component-adding steps, one step comprising adding part of the diamine to the molten dicarboxylic acid until the molar ratio of the diamine to the dicarboxylic acid is brought to within the range of from 0.900 to 0.990 while raising continuously the temperature of the reaction mixture to a temperature not exceeding about 5°C above the melting point of the object polyamide and the other step comprising adding the remainder of the diamine to the reaction mixture maintained at a temperature higher than about 10 °C, but not exceeding about 35 °C above the melting point of the object polyamide until the overall molar ratio of the diamine to the dicarboxylic acid is brought to within the range of from 0.995 to 1.005.