Process for enabling secondary expansion of expandable beads

摘要

The present invention enables the secondary expansion of lightweight foamed beads. The foamed beads are produced using a compound comprising a compostable or biobased polyester and a physical blowing agent as well as a chemical blowing agent. Secondary expansion can be used either to lower the density of the foamed bead further or to enable expansion of the beads during molding to promote fusion. The foam beads can be produced using conventional melt processing techniques, such as single and twin-screw extrusion processes.

主权项

1. A method comprising:
meltprocessing an admixture comprising a first blowing agent and a second blowing agent forming an extrudate to form a partially foamed compostable or biobased polymer extrudate bead comprising a chemical blowing agent that is introduced during meltprocessing; where said chemical blowing agent causes subsequent expansion of the extrudate bead.