Abstract: In the production method of the present invention, a copolyester of intended sublimable diol proportion is produced by the reaction of a dicarboxylic acid and/or an ester-forming derivative thereof with a sublimable diol and a non-sublimable diol with an increased conversion of the sublimable diol. Since the escape of the sublimable diol is effectively prevented, the process solves the problem of clogging pressure-reduced pipes, etc. of an apparatus for polyester resin production.

Abstract: There is disclosed A polyester based resin composition (D) which comprises a polyamide resin (A) and a polyester resin (B), or a polyamide resin (A), a polyester resin (B) and a polyethylene terephthalate resin (C), characterized in that the polyester resin (B) is obtained by polycondensation of a dicarboxylic acid component containing 0.5 to 60 mol % of a dicarboxylic acid having a cyclic acetal skeleton and/or a diol component containing 0.5 to 60 mol % of a diol having a cyclic acetal skeleton, and that the blending proportions of the polyamide resin (A), the polyester resin (B) and the polyethylene terephthalate resin (C) are each in the range of 1 to 99% by weight, 1 to 99% by weight and 0 to 98% by weight, respectively on the basis of total sum weight of the components (A), (B) and (C). There is further disclosed a molded product (film, sheet, thin wall hollow container, etc.).

Abstract: The polyester resin of the present invention is produced by polymerizing a monomer mixture comprising a glycol component containing 5 to 60 mol % of a spiroglycol represented by Formula I: and 30 to 95 mol % of ethylene glycol, and a dicarboxylic acid component containing 80 to 100 mol % of terephthalic acid and/or an ester thereof. The polyester resin has (1): an intrinsic viscosity of 0.4 to 1.5 dL/g, (2) a melt viscosity of 700 to 5,000 Pa·s, (3) a molecular weight distribution of 2.5 to 12.0; and (4) a glass transition temperature of 90° C. or higher and a cooling crystallization exotherm peak of 5 J/g or lower. The polyester resin of the present invention is excellent in heat resistance, transparency, mechanical properties, moldability and fabrication qualities and useful for producing shaped articles such as films, sheets, hollow containers and foamed products.

Abstract: The polyester resin of the present invention is produced by polymerizing a monomer mixture comprising a glycol component containing 5 to 60 mol % of a spiroglycol represented by Formula I: 1