PROCESS FOR PRODUCING POLYESTER AND COPOLYESTER BY USING POLYCONDENSATION OF INITIAL COMPONENTS CREATING POLYESTER AND USE OF THE POLYCONDENSING CATALYSTS

摘要

PCT No. PCT/EP94/04333 Sec. 371 Date Jul. 5, 1996 Sec. 102(e) Date Jul. 5, 1996 PCT Filed Jan. 2, 1995 PCT Pub. No. WO95/18839 PCT Pub. Date Jul. 13, 1995For the preparation of polyesters and copolyesters, titanium dioxide/silicon dioxide coprecipitates having a composition of TiO2:SiO2=90:10 to 20:80 mol/mol and/or titanium dioxide/zirconium dioxide coprecipitates having a composition of TiO2 : ZrO2=95:5 to 70:30 mol/mol are proposed as polycondensation catalysts. They have a higher catalytic activity than Sb2O3, so that the preferred amount used is only 10 to 100 ppm, based on the esters or oligoesters to be subjected to polycondensation.