| 摘要 |
PURPOSE:To make it possible to decrease acetaldehyde formation during melt molding and to lower the acetaldehyde content of a molding such as a food container, by specifying the conditions of esterification and polycondensation. CONSTITUTION:A polyester is produced from a terephthalic acid-based dicarboxylic acid and an ethylene glycol-based glycol. The esterification is performed so that the glycol to dicarboxylic acid molar ratio at the end of the esterification may be 1.02-1.10. The reaction mixture is subjected to a polycondensation reaction to obtain a polyester prepolymer of anintrinsic viscosity of 0.3-0.7. This polyester prepolymer is subjected to solid-state polymerization. The obtained polyester for blow molding has an intrinsic viscosity of 0.60-10, an acetaldehyde content <=100ppm and the ratio of the number of terminal carboxyl groups to the total of the terminal groups of 40-70%.
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