To obtain the subject composition not depositing a germanium compound, even when stored for a long period, and useful for producing polyester resins excellent in transparency, impact resistance and the like by including the germanium compound, water, an amine compound and a specific amount of a dihydric alcohol.
This catalyst composition comprises (A) a germanium compound such as germanium dioxide, (B) water, (C) an amine compound such as tetraethylammonium hydroxide, and (D) a dihydric alcohol such as ethylene glycol in an amount of ≤55 wt.% or ≥85 wt.% based on the total amount of the composition. The component A is preferably added in an amount of 0.01-0.1 mol.%, and the component C is preferably added in an amount of 0.3-1.0 fold mole that of the component A. The pH of the catalyst composition is preferably ≤5.0 or ≥8.5. The catalyst composition is useful for producing polyethylene terephthalate, polybutylene terephthalate or the like.
FUJITA AKIHARU
HIRAYAMA TAKASHI
