Method for preventing scale formation in a continuous ester-interchange reaction for production of polyesters

摘要

Scale formation in a continuous ester-interchange reaction for the production of polyesters, is prevented by subjecting a dialkyl ester of a difunctional carboxylic acid at least 80 mole% of which consists of terephthalic acid and at least one glycol to a continuous ester-interchange reaction catalyst in the presence of a catalytic amount of an ester-interchange reaction catalyst composed of a manganese compound and a lithium compound, the amount of said ester-interchange reaction catalyst being the one which meets the following expressions (i) and (ii) (I) 0.015<X + Y<0.