Abstract: A hollow article or sheet of a copolyester which comprises, as main components, terephthalic acid as a dicarboxylic acid component and ethylene glycol as a diol component and which is characterized by:(1) isophthalic acid as a dicarboxylic acid component being from 0.5 to 3.0 mol %,(2) diethylene glycol as a diol component being from 1.0 to 2.5 mol %,(3) the intrinsic viscosity being from 0.60 to 1.50 dl/g,(4) the concentration of terminal carboxyl groups being at most 18 eq/ton, and(5) the content of a cyclic trimer being at most 0.40% by weight.

Abstract: A copolyester which comprises, as main components, terephthalic acid as a dicarboxylic acid component and ethylene glycol as a diol component and which is characterized by:(1) isophthalic acid as a dicarboxylic acid component being from 0.5 to 3.0 mol %,(2) diethylene glycol as a diol component being from 1.0 to 2.5 mol %,(3) the intrinsic viscosity being from 0.60 to 1.50 dl/g,(4) the concentration of terminal carboxyl groups being at most 18 eq/ton, and(5) the content of a cyclic trimer being at most 0.40% by weight.

Abstract: A copolyester comprising a dicarboxylic acid component comprising (a) 80 to 99.5 mol % of terephthalic acid or an ester forming derivative thereof and (b) 0.5 to 4.5 mol % of a phenylenedioxy diacetic acid or an ester forming derivatives thereof and a diol component is described. Hollow containers and stretched film produced from the copolyester are further described. The copolyester has a high transparency, superior gas barrier property, mechanical strength, water resistance and heat resistance. In addition, since the copolyester has a low oligomer content, it scarcely contaminates a mold used in molding process, which leads to a high productivity. The molded article produced from the copolyester can be used widely as packaging materials including various films, sheets and containers. Moreover, since a molded article having superior properties is obtained form the copolyester alone, it is possible to manufacture various packaging materials without using a complicated apparatus and complicated process.

Abstract: Disclosed herein are a coppolymerized polyester produced by copolymerizing a dicarboxylic acid component (A) comprising(a) 10 to 90 mol % of isophthalic acid or an ester forming derivative thereof,(b) 10 to 60 mol % of a phenylenedi(oxyacetic acid) represented by the formula [I]: ##STR1## (wherein R.sup.1, R.sup.2, R.sup.3, and R.sup.4 each represent a hydrogen atom, an alkyl group having 1 to 6 carbon atom, an alkoxy group having 1 to 6 carbon atom, a phenyl group, a chlorine atom, a bromine atom or a fluorine atom), or as ester forming derivative thereof, and(c) 0 to 45 mol % of a naphthalenedicarboxylic acid or an ester forming derivative thereof, anda diol component (B); and a polyester composition containing the copolymerized polyester.

Abstract: Disclosed herein is a thermoplastic polyester molded article comprising a thermoplastic polyester and at least one of the specified diimide compounds, the latter being blended in an amount effective for ultraviolet screening. The polyester molded article and a composition for producing it according to this invention is capable of screening ultraviolet rays not only in the short wavelength region but also in the long wavelength region and has uniform dispersion stability and thermal stability. The molded articles of the present invention are free of undesired coloration and deposition of extraneous matter.

Abstract: Disclosed herein are a copolymerized polyester produced by copolymerizing a dicarboxylic acid component (A) comprising(a) 10 to 90 mol % of isophthalic acid or an ester forming derivative thereof,(b) 10 to 60 mol % of a phenylenedi(oxyacetic acid) represented by the formula [I]: ##STR1## (wherein R.sup.1, R.sup.2, R.sup.3, and R.sup.4 each represent a hydrogen atom, an alkyl group having 1 to 6 carbon atom, an alkoxy group having 1 to 6 carbon atom, a phenyl group, a chlorine atom, a bromine atom or a fluorine atom), or an ester forming derivative thereof, and(c) 0 to 45 mol % of a naphthalenedicarboxylic acid or an ester forming derivative thereof, anda diol component (B); and a polyester composition containing the copolymerized polyester.

Abstract: Disclosed herein is a thermoplastic polyester resin composition comprising a thermoplastic polyester resin and an amount effective in ultraviolet screening of at least one of naphthalenetetracarboxylic acids, acid anhydrides thereof, imides thereof and esters thereof.