| 摘要 |
PURPOSE:To produce a polyester for a transparent film excellent in electrostatic castability, by reacting a dicarboxylic acid containing a P compound with a bis(beta-hydroxyethyl) terephthalate containing a glycol. CONSTITUTION:A slurry formed by mixing a dicarboxylic acid (e.g., terephthalic acid) containing a P compound (e.g., phosphoric acid) in an amount to provide 0.03X10<-3>-2.0X10<-3>mol of P per mol of the dicarboxylic acid with a glycol (e.g., ethylene glycol) at a molar ratio of 1:1.05-1 is added continuously or intermittently to bis(beta-hydroxyethyl) terephthalate (oligomer) to perform transesterification at 240-280 deg.C and normal pressure or a pressure of 0.3-3.0kg/cm<2> to a degree of esterification of 90-98%. A vivalent metal compound (e.g., zinc acetate) in an amount equivalent to 0.08X10<-3>-2.0X10<-3>mol of the metal of the metal per mol of the dicarboxylic acid is added to the reaction system, and the reaction mixture is polycondensed in the presence of a polycondensation catalyst (e.g., Sb2O3) to obtain a polyester of an intrinsic viscosity of 0.6-0.7.
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