| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for capable of producing a high quality copolyester for a long time stably and continuously at a low cost while suppressing the quality change. SOLUTION: This method for continuously producing the copolyester comprising a process 1: slurry preparation process; process 2: esterification reaction process; and process 3: polycondensation reaction process, is provided by feeding a phosphorus compound by≥1 time through the process 1 to process 3, introducing solid neopentyl glycol newly into the slurry preparation vessel in the process 1, additionally feeding a glycol component containing the neopentyl glycol from the second esterification reaction vessel and afterwards in the process 2, setting the reaction temperature in the esterification reaction vessel as lower than that in the previous stage, also at the feeding of the phosphorus compound and afterwards, reducing the phosphorus atom content in distilled out glycol component as≤10 ppm by a distillation column so as to circulate for reusing it, and regulating the carboxy terminal group concentration of a polyester oligomer at the exit of the process 2 as within±10% of a set value. COPYRIGHT: (C)2008,JPO&INPIT
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