| abstract |
A novel catalyst system, a process for using the novel catalyst system, and a product made from the process is described. The novel catalyst system is specific for producing polyethylene terephthalate made from reacting terephthalic acid and ethylene glycol, wherein the catalyst system includes at least 650 ppm antimony; cobalt and/or zinc, and at least one of zinc, magnesium, manganese or calcium. The antimony is generally present from about 650 ppm to about 1100 ppm. The cobalt and/or zinc is usually present from about 15 ppm to about 60 ppm, and the zinc, magnesium, manganese or calcium, as the third component, is generally present from about 10 ppm to about 150 ppm. The amounts of all catalyst components are based on the theoretical yield of the polymer. Using the novel catalyst system to produce PET drastically increases the polymerization rate. In the process, the novel catalyst system can be introduced any time before the polycondensation stage of the manufacturing process. |