Patent ID: 6358578
Filing Date: 2002-03-19
Classification: C08G,Y10T

Abstract:
In a method of producing polyester from monomers of terephthalic acid, 2,6-naphthalene dicarboxylic acid, or both suitable for processing into films, bottles, molded articles, or fibers by (1) transesterification of at least a dicarboxylic acid ester or esterification of at least a dicarboxylic acid with at least a diol and (2) subsequent precondensation and polycondensation in the presence of a polycondensation catalyst, the improvement comprising catalyzing polycondensation with a carbon-containing co-catalyst in addition to the polycondensation catalyst, wherein the carbon-containing co-catalyst is activated charcoal added in quantities of 0.1 to 1000 ppm relative to the polyester and at a ratio by weight of catalyst to co-catalyst of 1:0.01 to 1:5 and (a) when the polyester is produced by esterification the carbon-containing co-catalyst is added before, during or after esterification and/or before or during the first half of the polycondensation and (b) when the polyester is produced by transesterification the carbon-containing co-catalyst is added after transesterification and before or during the first half of the polycondensation, wherein the polyester product has an intrinsic viscosity of at least 0.4 dL/g.