Abstract: The present invention provides a resin composition comprising polylactic acid and aliphatic polyester carbonate, which has practically adequate heal-resistance temperature, moldability, thermostability, solvent resistance and high mechanical strength, as well as a molded article thereof. In the resin composition, the Vicat softening point is 60° C. or more, the tensile modulus of elasticity is 0.9 GPa or more, the modulus in flexure is 0.6 GPa or more, and the mixing ratio of polylactic acid (A) and aliphatic polyester carbonate (B), in terms of the ratio of (A)/(B) by weight, is 95/5 to 5/95.

Abstract: The present invention provides a resin composition comprising polylactic acid and aliphatic polyester carbonate, which has practically adequate heat-resistance temperature, moldability, thermostability, solvent resistance and high mechanical strength, as well as a molded article thereof. In the resin composition, the Vicat softening point is 60° C. or more, the tensile modulus of elasticity is 0.9 GPa or more, the modulus in flexure is 0.6 GPa or more, and the mixing ratio of polylactic acid (A) and aliphatic polyester carbonate (B), in terms of the ratio of (A)/(B) by weight, is 95/5 to 5/95. Further, the present invention provides a biodegradable injection-molded article having improvements in mechanical characteristics and impact resistance and superior disposal properties, particularly having strength enough to make it usable as a headgear material for use in helmets.