Abstract: The present invention provides a polyester resin and a hollow molded body containing reduced amounts of cyclic trimer and aluminum-based foreign matter, with maintained catalytic activity and a reduced catalyst cost. A polyester resin, comprising an aluminum compound and a phosphorus compound, and satisfying the following (1) to (3): (1) a content of aluminum element in the polyester resin is 9 to 19 ppm by mass, (2) a content of phosphorus element in the polyester resin is 22 to 40 ppm by mass. and (3) a mole ratio of phosphorus element to aluminum element in the polyester resin is 1.55 or more and 1.85 or less.

Abstract: A method for producing polyester resin containing an ethylene terephthalate structural unit of not less than 85 mol%, the method comprising: a melt-polymerization step of continuously performing melt-polymerization in two or more polymerization vessels by using an aluminium compound and a phosphorus compound as a polymerization catalyst; and a solid phase polymerization step of performing solid phase polymerization after the melt-polymerization step, wherein a polymerization in a final polymerization vessel of the melt-polymerization step satisfies a condition represented by the following formula: 410?T*RT*(P/Al)?580, wherein T represents a temperature (°C) in the final polymerization vessel, RT represents residence time (hour) in the final polymerization vessel, and P/Al represents a molar ratio of phosphorus element to aluminium element in the polyester resin.

Abstract: The present invention relates to a copolymerized polyester resin which can give film characteristics being suitable for a use as a heat-shrinkable label and which is excellent in the recycling property. According to the present invention, there is provided a copolymerized polyester resin which contains dicarboxylic acid and diol as constituting components, wherein the copolymerized polyester resin 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 from 18 to 32% by mole and a content of diethylene glycol is from 7 to 15% by mole when a total amount of the whole diol component is taken as 100% by mole, and wherein a molar proportion of each phosphorus compound contained in the copolymerized polyester resin and having a specific structure satisfies the specific inequality (1).

Abstract: The present invention is to provide a high-quality polyester resin that is produced by using a polymerization catalyst containing an aluminum compound and a phosphorus compound, that can reduce a catalyst cost, for which polymerization activity is high, and in which there is less foreign matter. The polyester resin contains an aluminum compound and a phosphorus compound used as a catalyst, and the amount of aluminum atom contained in the polyester resin is 9 to 20 ppm, the amount of phosphorus atom contained in the polyester resin is 13 to 31 ppm, a mole ratio of the phosphorus atom to the aluminum atom in the polyester resin is 1.32 to 1.80.