Teijin Limited

Shigehiro Ichihara

Tadashi Konishi

Yorihiko Omoto

Hisanori Murai

A process for preparing a polyester which comprises reacting a di-lower alkyl ester of a difunctional carboxylic acid at least 90 mole% of which consists of terephthalic acid with a polymethylene glycol containing 2 to 10 carbon atoms at least 90 mole% of which consists of ethylene glycol in the presence of an ester-interchange reaction catalyst to form an ester-interchange reaction product, and then polycondensing it in the presence of a polycondensation catalyst, wherein a substantially uniform solution in ethylene glycol of (A) 20 to 150 millimole%, based on said di-lower alkyl ester of the difunctional carboxylic acid, of calcium acetate and (B) 2 to 25 millimole%, based on said di-lower alkyl ester, of cobalt acetate is used as the ester-interchange reaction catalyst.

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Matsuyama, Japan

Shigehiro Ichihara