Patent ID: 6060579
Filing Date: 2000-05-09
Classification: C08G

Abstract:
A method for producing polybutylene terephthalate comprising:(A) continuously esterifying a dicarboxylic acid component consisting essentially of terephthalic acid with a diol component consisting essentially of 1,4-butanediol, wherein the esterification is effected in a molar ratio of the diol component to the dicarboxylic acid component to fall between 1.1 and 1.6, in the presence of a combination of an organic titanium compound and an organic tin compound that satisfies the following requirement:amount of organic titanium compound (mol %).ltoreq.0.08.times.P-0.07where P=molar ratio of diol component to dicarboxylic acid component, resulting in an oligomer; and(B) continuous polycondensation of said oligomer.