| 摘要 |
PROBLEM TO BE SOLVED: To provide a method or apparatus for continuously producing polybutylene terephthalate in good profitability. SOLUTION: This method for continuously producing the polybutylene terephthalate, comprising feeding a mixture of an aromatic dicarboxylic acid or its derivative and a glycol compound as raw materials into the first reactor to produce the oligoester having an average polymerization degree of 3 to 7 at a temperature of 220 to 275 degree, producing a low polymer having an average polymerization degree of 20 to 40 at a temperature of 220 to 280 degree at a pressure of the atmospheric pressure to 133 Pa in the second reactor, and then polycondensing the low polymer at a temperature of 220 to 280 degree at a pressure of 220 to 13.3 Pa in the third reactor to produce the polybutylene terephthalate having an average polymerization degree 70 to 180 is characterized in that the third reactor is equipped with a rotatable stirring rotor having stirring blade blocks corresponding to the viscosity of a treating liquid therein, and does not have a rotation shaft in the center of the stirring blades. COPYRIGHT: (C)2006,JPO&NCIPI
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