Abstract: Some embodiments of the present invention provides a method of preparing a thermoformed article composed of polylactic acid that includes the steps of providing a foam sheet comprising polylactic acid having a D-lactic acid stereo-isomer content that is about 3 mole % or less, exposing the sheet to a temperature of at least about 190° C., and forming the heated sheet in a mold at a mold temperature that is at least about 50° C. and for a length of time to form a thermoformed article having a PLA crystalline content of at least about 10%. Surprisingly, it has been discovered that heat resistant thermoformed articles can be prepared in accordance with embodiments of the invention wherein the time required for forming the foam sheet into a molded article is less than about 10 seconds.

Abstract: Some embodiments of the present invention provides a method of preparing a thermoformed article composed of polylactic acid that includes the steps of providing a foam sheet comprising polylactic acid having a D-lactic acid stereo-isomer content that is about 3 mole % or less, exposing the sheet to a temperature of at least about 190° C., and forming the heated sheet in a mold at a mold temperature that is at least about 50° C. and for a length of time to form a thermoformed article having a PLA crystalline content of at least about 10%. Surprisingly, it has been discovered that heat resistant thermoformed articles can be prepared in accordance with embodiments of the invention wherein the time required for forming the foam sheet into a molded article is less than about 10 seconds.