Discontinuous process for polycondensation of terephthalic acid and 1,4-bis(hydroxymethyl)cyclohexane

摘要

Process for discontinuous production of polyesters by esterification of terephthalic acid with a definite excess of 1,4-bis(hydroxymethyl)cyclohexane in the presence of a titanium catalyst at 180 DEG to 300 DEG C. and 0.8 to 1.5 bar up to a conversion of 98.0% to 99.6%, then precondensation with the addition of more titanium catalyst at 270 DEG to 300 DEG C. and 500 to 5 mbar up to a conversion of 99.5% to 99.9% and polycondensation at 295 DEG to 310 DEG C. and less than 1.5 mbar up to a conversion corresponding to 40% to 95% of the maximum possible viscosity.