Patent ID: 6703475
Filing Date: 2004-03-09
Classification: C08G,D01F

Abstract:
A process for continuous production of copolyamides based on a lactam (I), a diamine (II) and a dicarboxylic acid (III), which comprisesa) preparing a polymer (V) in a first reaction zone by reacting a mixture (IV) comprising a diamine (II), a dicarboxylic acid (III), water, and a lactam (I), at a pressure of from 1.3*105 to 2.5*105 Pa in the entry zone of the reaction zone and at a temperature above the melting point of the polymer (V) to a conversion, based on the molar amounts of diamine (II) and dicarboxylic acid (III), of at least 80%, b) preparing a polymer (VII) in a second reaction zone by reacting a mixture (VI) comprising lactam (I), water, a diamine (II) and a dicarboxylic acid (III) at a pressure of from 5*105 to 40*105 Pa and at a temperature above the melting point of the polymer (VII) to a conversion, based on the molar amount of lactam (I), of at least 80%, with the proviso that the molar amount of lactam (I) in said mixture (IV) is less than the molar amount of lactam (I) in the mixture (VI), and with the proviso that the molar amount of diamine (II) and dicarboxylic acid (III) in said mixture (VI) is less than the molar amount of diamine (II) and dicarboxylic acid (III) in the mixture (IV), and then c) preparing a polymer (VIII) in a third reaction zone by reacting the polymer (V) and the polymer (VII) with each other at a pressure of from 1*105 to 1.5*105 Pa in the entry zone of the reaction zone and at temperatures above the melting point of the polymer (VIII), said polymer (VIII) having a 95Â° C. water extractables content, based on lactam (I), diamine (II) and dicarboxylic acid (III), of not more than 10% by weight, and d) extracting the polymer (VIII) with water to obtain the copolyamide.