| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for producing a polyester resin, capable of rapidly reducing a cyclic trimer in solid phase polymerization, and providing a polyester resin suitably used for a beverage container while hardly causing mold fouling in heating since the increase of the cyclic trimer is minimized. SOLUTION: In the method for producing a polyester resin by liquid-phase polycondensing a low-order condensate of an aromatic dicarboxylic acid and an aliphatic diol followed by solid-phase polycondensing, the liquid-phase polycondensation is performed so as to satisfy the following expressions (a), (b) and (c), and the solid-phase polycondensation is performed so as to satisfy the following expression (f). (a) 0.1≤M1≤1.0, (b) 0.01≤M2≤10, (c) 0.1≤M2/M1, and (f) IV≥0.70 (M1 is the molar amount of Ge atom per ton of the produced polyester resin, M2 is the molar amount of alkali metal atom per ton of the produced polyester resin, and IV is the specific viscosity (dl/g) of the produced polyester resin). COPYRIGHT: (C)2009,JPO&INPIT |
