Abstract: The invention provides a copolymerized polyester resin which contains terephthalic acid as a main component of a dicarboxylic acid component; and contains ethylene glycol as a main component of a diol component, wherein a content of neopentyl glycol is more than 15% by mole and not more than 40% by mole and a content of diethylene glycol is from 6 to 20% by mole when a total amount of the whole diol component is taken as 100% by mole, wherein a content of a cyclic dimer consisting of terephthalic acid, neopentyl glycol and diethylene glycol is 5000 ppm or less, and wherein a content of a cyclic trimer consisting of terephthalic acid and ethylene glycol is 5000 ppm or less.

Abstract: The present invention is a copolymerized polyester resin which contains a dicarboxylic acid component and diol components as constituting components, wherein greater than or equal to 90 mol % of terephthalic acid is contained as the dicarboxylic acid component, 39 to 79 mol % of ethylene glycol, 20 to 60 mol % of neopentyl glycol and 1 to 5 mol % of diethylene glycol are contained as the diol components, the reduced viscosity of the resin is greater than or equal to 0.50 dl/g, the number of contaminants having a particle diameter of greater than or equal to 5 ?m is less than or equal to 100 per 1 mm2 in a sample of the copolymerized polyester resin having a thickness of 0.8 to 0.9 mm. The copolymerized polyester resin has a higher degree of clarification than conventionally known copolymerized polyesters and also has excellent color hue and heat resistance.

Abstract: The present invention is a copolymerized polyester resin which contains a dicarboxylic acid component and diol components as constituting components, wherein greater than or equal to 90 mol % of terephthalic acid is contained as the dicarboxylic acid component, 39 to 79 mol % of ethylene glycol, 20 to 60 mol % of neopentyl glycol and 1 to 5 mol % of diethylene glycol are contained as the diol components, the reduced viscosity of the resin is greater than or equal to 0.50 dl/g, the number of contaminants having a particle diameter of greater than or equal to 5 ?m is less than or equal to 100 per 1 mm2 in a sample of the copolymerized polyester resin having a thickness of 0.8 to 0.9 mm. The copolymerized polyester resin has a higher degree of clarification than conventionally known copolymerized polyesters and also has excellent color hue and heat resistance.