| 摘要 |
The invention relates to a method for producing polyesters and copolyesters. According to said method, coprecipitates are used as polycondensation catalysts alone or as mixtures, which coprecipitates were produced by simultaneous hydrolytic precipitation of a titanium compound and a metal compound of a metal selected from the groups IA, IIA, VIIIA, IB, IIB, IIIB and IVB. The titanium compound and the metal compound independently of each other are an alkylate, alcoholate or carboxylate of the titanium or metal and the molar ratio of titanium compound to metal compound is >=50:50 mol/mol. The coprecipitates have a greater catalytic activity than Sb2O 3, so that the preferred quantity used is only between 10 and 100 ppm in relation to the esters or oligo-esters to be polycondensated. |
