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.

Abstract: The invention provides a polyester resin for heat-shrinkable film which contains terephthalic acid as a main component of a dicarboxylic acid component, contains ethylene glycol as a main component of a diol component, and contains from 18 to 32% by mole of neopentyl glycol and from 7 to 15% by mole of diethylene glycol when a total amount of the whole diol component in total polyester resin components is taken as 100% by mole. The polyester resin has (i) an intrinsic viscosity (IV) of not less than 0.65 and less than 0.70 dl/g, (ii) a carboxyl end group concentration (AV) of 8-25 eq/t, (iii) a color b value of 1.0-8.0 in an L*a*b* color system, and (iv) aluminum and phosphorus atoms, wherein the aluminum atoms are present in an amount of 15-40 ppm, and wherein the molar ratio of the phosphorus atoms to the aluminum atoms is 1.8-2.6.

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: A polyester resin that can be beneficially employed as one finding application in deactivation of polycondensation catalysts for polyester production and suppression of forming of acetaldehyde and other aldehydes and cyclic ester oligomers at molding stage. In particular, there is provided a polyester resin composed mainly of an aromatic dicarboxylic acid component and a glycol component wherein a phosphorus compound is incorporated through copolymerization or blending in an amount of 100 to 10,000 ppm in terms of phosphorus element, characterized in that the contents of Zn element, Fe element, Ni element and Cr element are not greater than specified values.