Abstract: Provided is a hydrolysis-resistant polyester film having a low acid value due to suppression of acid value-increase during film formation. The hydrolysis-resistant polyester film of the present invention is a polyester film comprising a polyester resin composition, wherein the polyester resin composition that forms the films comprises 0.03 to 6.7 eq/ton of hindered phenol structural units, an acid value of a polyester that forms the film is less than 25 eq/ton, and an intrinsic viscosity of a polyester that forms the film is more than 0.64 dL/g and not less than 0.90 dL/g.

Abstract: The present invention is an aliphatic polyester resin in which a polyhydroxy acid skeleton is a main component, manufactured using a polymerization catalyst, characterized in that a specific organophosphorus compound is copolymerized in the resin. Activity of the polymerization catalyst contained in the aliphatic polyester resin of the present invention after the polymerization is well lowered and a lactide is hardly produced even by heating after the polymerization or after the manufacture.

Abstract: Provided is a polylactic acid resin composition useful as a molding material and a packaging material. The polylactic acid resin composition comprises a resin composition (l) comprising poly-L-lactic acid having an L-isomer content of 90-100 mol % as the main component and a resin composition (d) comprising poly-D-lactic acid having a D-isomer content of 90-100 mol % as the main component, the resin compositions (l) and (d) having been alternately stacked so that each layer has a thickness of 0.01-2.5 ?m. The polylactic acid resin composition has specific thermal properties, can be used at high temperatures even after high-temperature melt molding, and can give molded polylactic acid articles having excellent suitability for various kinds of processing, such as printing, and having excellent transparency, etc. Also provided is a stretched polylactic acid resin film obtained by heating the polylactic acid resin composition to 280° C.

Abstract: Provided is a hydrolysis-resistant polyester film having a low acid value due to suppression of acid value-increase during film formation. The hydrolysis-resistant polyester film of the present invention is a polyester film comprising a polyester resin composition, wherein the polyester resin composition that forms the films comprises 0.03 to 6.7 eq/ton of hindered phenol structural units, an acid value of a polyester that forms the film is less than 25 eq/ton, and an intrinsic viscosity of a polyester that forms the film is more than 0.64 dL/g and not less than 0.90 dL/g.

Abstract: Provided is a polylactic acid resin composition useful as a molding material and a packaging material. The polylactic acid resin composition comprises a resin composition (l) comprising poly-L-lactic acid having an L-isomer content of 90-100 mol % as the main component and a resin composition (d) comprising poly-D-lactic acid having a D-isomer content of 90-100 mol % as the main component, the resin compositions (l) and (d) having been alternately stacked so that each layer has a thickness of 0.01-2.5 ?m. The polylactic acid resin composition has specific thermal properties, can be used at high temperatures even after high-temperature melt molding, and can give molded polylactic acid articles having excellent suitability for various kinds of processing, such as printing, and having excellent transparency, etc. Also provided is a stretched polylactic acid resin film obtained by heating the polylactic acid resin composition to 280° C.

Abstract: The present invention is an aliphatic polyester resin in which a polyhydroxy acid skeleton is a main component, manufactured using a polymerization catalyst, characterized in that a specific organophosphorus compound is copolymerized in the resin. Activity of the polymerization catalyst contained in the aliphatic polyester resin of the present invention after the polymerization is well lowered and a lactide is hardly produced even by heating after the polymerization or after the manufacture.