| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a polyethylene terephthalate in high catalytic activity. SOLUTION: The method for producing the PET comprises in polycondensing a low-order condensate between terephthalic acid and ethylene glycol in the presence of a catalyst in a liquid phase to give a liquid-phase polycondensed PET and then polycondensing the liquid-phase polycondensed PET in a solid phase to give the PET, using a titanium-based catalyst as a catalyst and polycondensing the liquid-phase polycondensed PET having a COOH group concentration of≤50 equivalents/ton in a solid phase. The titanium-based catalyst is a hydrolyzate of a titanium halide, a solid titanium complex obtained by dehydrating and drying the hydrolyzate in the presence of a polyhydric alcohol, a solution obtained by dissolving the hydrolyzate or the solid titanium complex in a solution containing ethylene glycol, a hydrolyzate of a mixture of a titanium halide and a compound of at least one kind of an element selected from elements except titanium, a solid titanium complex obtained by dehydrating and drying this hydrolyzate in the presence of a polyhydric alcohol or a solution obtained by dissolving this hydrolyzate or the solid titanium complex in a solution containing ethylene glycol. COPYRIGHT: (C)2005,JPO&NCIPI
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