| 摘要 |
PURPOSE: Provided is a process for producing polyethylene terephthalate excellent in various properties by transesterifying and polycondensing waste polyethylene terephthalate only or a mixture of the waste polyethylene terephthalate and dimethyl terephthalate with ethylene glycol. CONSTITUTION: The process comprises the steps of: transesterifying the waste polyethylene terephthalate only or the mixture of the waste polyethylene terephthalate and the dimethyl terephthalate with the ethylene glycol in the presence of 0.01-0.4pts.wt.(based on 100pts.wt. of the waste polyethylene terephthalate only or the mixture of the waste polyethylene terephthalate and the dimethyl terephthalate) of a transesterification catalyst, wherein the amount of the ethylene glycol is the sum of 0.38-0.64 times of dimethyl terephthalate weight and 1.5-4.0 times of waste polyethylene terephthalate weight; adding 0.01-0.20pts.wt. of a polycondensation catalyst and 0.005-0.2pts.wt. of a stabilizer; firstly and secondly polycondensing. The transesterification catalyst is at least one compound selected from calcium acetate, manganese acetate, zinc acetate, lead acetate, and cobalt acetate.
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