Abstract: A polylactic acid resin composition includes: 0.005 parts by weight to 1.2 parts by weight of a metal phosphate represented by Formula (1): MxHyPOz??(1) (in Formula (1), M is an alkali metal atom or an alkaline earth metal atom, and x, y, and z are integers satisfying 1?x?2, 1?y?4, and 2?z?8, respectively) with respect to 100 parts by weight of a polylactic acid resin including a poly-L-lactic acid component and a poly-D-lactic acid component, wherein a crystallization enthalpy of crystals in the polylactic acid resin is not less than 5 J/g when a temperature of the polylactic acid resin composition is increased to 250° C., and the temperature is kept constant for 3 minutes, followed by decreasing the temperature at a cooling rate of 20° C./min in differential scanning calorimetry.

Abstract: A method of producing a polylactic acid block copolymer constituted of a segment(s) composed of L-lactic acid units and a segment(s) composed of D-lactic acid units, includes obtaining a mixture by mixing poly-L-lactic acid and poly-D-lactic acid one of which has a weight average molecular weight of 60,000 to 300,000 and the other of which has a weight average molecular weight of 10,000 to 50,000, the mixture having a weight average molecular weight of not less than 90,000 and a degree of stereocomplexation (Sc) satisfying: Sc=?Hh/(?Hl+?Hh)×100>60 (wherein ?Hh represents the heat of fusion of stereocomplex crystals (J/g), and ?Hl represents the heat of fusion of crystals of poly-L-lactic acid alone and crystals of poly-D-lactic acid alone (J/g)); and subsequently subjecting the mixture to solid-phase polymerization at a temperature lower than the melting point of the mixture.

Abstract: A polylactic acid resin composition includes: 0.005 parts by weight to 1.2 parts by weight of a metal phosphate represented by Formula (1): MxHyPOz??(1) (in Formula (1), M is an alkali metal atom or an alkaline earth metal atom, and x, y, and z are integers satisfying 1?x?2, 1?y?4, and 2?z?8, respectively) with respect to 100 parts by weight of a polylactic acid resin including a poly-L-lactic acid component and a poly-D-lactic acid component, wherein a crystallization enthalpy of crystals in the polylactic acid resin is not less than 5 J/g when a temperature of the polylactic acid resin composition is increased to 250° C., and the temperature is kept constant for 3 minutes, followed by decreasing the temperature at a cooling rate of 20° C./min in differential scanning calorimetry.

Abstract: A method for producing a crystallized polyester comprises the crystallization step of applying a shear and/or a pressure to a polyester selected from an aliphatic polyester and a polyalkylene terephthalate at a temperature of (Tm?70° C.) to (Tm+20° C.), where Tm is a melting point of the polyester, thereby converting the polyester into a state having a crystallinity of 10% or more and fluidity.

Abstract: A polylactic acid block copolymer constituted by a poly-L-lactic acid segment(s) contains as a major component L-lactic acid and a poly-D-lactic acid segment(s) contains as a major component D-lactic acid, the polylactic acid block copolymer satisfying Inequalities (1) and (2): Sc=?Hh/(?Hl+?Hh)×100>80 (1); 1<(Tm?Tms)/(Tme?Tm)<1.8 (2). The polylactic acid block copolymer has excellent transparency, heat resistance and mechanical properties, which forms a polylactic acid stereocomplex.

Abstract: A method of producing a polylactic acid block copolymer constituted of a segment(s) composed of L-lactic acid units and a segment(s) composed of D-lactic acid units, includes obtaining a mixture by mixing poly-L-lactic acid and poly-D-lactic acid one of which has a weight average molecular weight of 60,000 to 300,000 and the other of which has a weight average molecular weight of 10,000 to 50,000, the mixture having a weight average molecular weight of not less than 90,000 and a degree of stereocomplexation (Sc) satisfying: Sc=?Hh/(?Hl+?Hh)×100>60 (wherein ?Hh represents the heat of fusion of stereocomplex crystals (J/g), and ?Hl represents the heat of fusion of crystals of poly-L-lactic acid alone and crystals of poly-D-lactic acid alone (J/g)); and subsequently subjecting the mixture to solid-phase polymerization at a temperature lower than the melting point of the mixture.

Abstract: A method for producing a crystallized polyester comprises the crystallization step of applying a shear and/or a pressure to a polyester selected from an aliphatic polyester and a polyalkylene terephthalate at a temperature of (Tm?70° C.) to (Tm+20° C.), where Tm is a melting point of the polyester, thereby converting the polyester into a state having a crystallinity of 10% or more and fluidity.