DISCONTINUOUS METHOD FOR MAKING A POLYAMIDE

摘要

The invention concerns a discontinuous method for making a polyamide from at least a diacid and at least a diamine. Said method comprises the following essential steps: a) preparing a liquid mixture of diacid and diamine with a diacid/diamine mol ratio > 1; b) adjusting the stoichiometry by adding diamine in the liquid mixture of diacid and diamine, until the difference ( DELTA TG = CTG ATG) between the amount of carboxylic terminal groups (CTG) and the amount of amine terminal groups (ATG), expressed in meq (or mmoles)/kg of the polymer reaches a predetermined setpoint value, the additional input of diamine being subjected at least at the end of the addition to an analysis of the mixture of diacid and diamine to determine the evolution of DELTA TG in time; c) polymerising with elimination of water until the desired degree of polymerisation is reached; provided that the liquid diacid/diamine mixture, non polymerised or at least partly polymerised, is maintained, in steps a) and b) at a temperature theta sufficient to maintain the medium in liquid state and avoid any solidification.