COMPOSTABLE OR BIOBASED FOAMS

摘要

The present invention describes compostable or biobased foams that are useful for fabricating foamed articles and methods for producing the same. The foams are produced using a compound comprising a compostable or biobased polyester and a blowing agent. Additives including plasticizers and chain extenders are optionally included in the compostable or biobased composition. These foams can be produced using conventional melt processing techniques, such as single and twin-screw extrusion processes. In one embodiment, foamed strand profiles are cooled and cut using conventional strand pelletizing equipment. In another embodiment, foamed beads are produced by cutting the foamed strand at the face of the extrusion die and the foamed bead or strand is subsequently cooled. The resulting compostable or biobased foamed bead has a specific gravity less than 0.15 g/cm3 and the foam is compostable, as determined by ASTM D6400.

主权项

1. A method of making compostable or biobased foam beads comprising:
mixing a biobased polymer and a physical blowing agent that does not contain a volatile organic component in an extruder wherein the extruder has a temperature that is above a melting point of the biobased polymer and wherein a biobased polymer melt is formed; extruding the biobased polymer melt by forcing the melt through an extrusion die opening to form an extrudate wherein the temperature at an exit of the extrusion die is about 30-50° C. lower than the melting temperature of the compostable or biobased polymer melt wherein the blowing agent expands within the extrudate upon exiting the extrusion die opening; and cutting the extrudate at the face of the die to produce biobased foam beads.