Abstract: A packaging laminate material comprises a paper substrate and a polyester resin layer provided on at least the innermost surface side of the substrate, wherein the polyester resin comprises dicarboxylic acid units comprising terephthalic acid and adipic acid and dihydroxy compound units comprising ethylene glycol and a second different dihydroxy compound. The polyester may also contain polyfunctional units derived from a polycarboxylic acid having a valence of 3 or more and/or derived from a polyglycol having a valence of 3 or more. The packaging laminate has a high heat-sealing strength, a small decrease in the heat-sealing strength even after the laminate is subjected to a hot water treatment or a hot hydrogen peroxide treatment, and is excellent in scent (odor) retention properties.

Abstract: In accordance with the present invention, there are provided polyester carbonate copolymers obtained by polymerization of a mixture of 20-80% by weight of an alkylene terephthalate oligomer [I] containing ethylene terephthalate as main structural units and having an intrinsic viscosity [.eta.], as measured at 25.degree. C. in o-chlorophenol, of less than 0.6 dl/g, and 20-80% by weight of a carbonate oligomer [II] containing 2,2-bis(4 -hydroxyphenyl)propane as main structural units and having an intrinsic viscosity [.eta.], as measured at 25.degree. C. in o-chlorophenol, of less than 0.6 dl/g, said copolymers having an intrinsic viscosity [.eta.], as measured at 25.degree. C. in o-chlorophenol, of 0.4-1.2 dl/g and a glass transition temperature (Tg) of 80.degree.-140.degree. C. with a single peak, and polyester resin compositions containing said copolymers, said resin composition being excellent in transparency, heat resistance and mechanical strength.