Patent ID: 8901271

Claim:
Process for making polyethylene terephthalate (PET) from ethylene glycol (EG), purified terephthalic acid (PTA) and optionally up to 6 mol % comonomer, using a mixed metal catalyst system and comprising: a) esterifying EG and PTA to form diethylene glycol terephthalate and oligomers (DGT), and b) melt-phase polycondensing DGT to form PET and EG, wherein the catalyst system substantially consists of a Sb-compound, a Zn-compound and Ti-glycolate as active components, at concentration of 70-160 ppm Sb, 20-70 ppm Zn and 0.5-20 ppm Ti (ppm metal based on PET), and optionally a P-compound.