LOW DENSITY FOAM, MIDSOLE, FOOTWEAR, AND METHODS FOR MAKING LOW DENSITY FOAM

摘要

Foamed thermoplastic elastomeric polyurethane and ethylene-vinyl acetate copolymer articles are made with a combination of a supercritical fluid and a non-supercritical fluid blowing agent.

主权项

1. A method for making a low density foamed article, comprising:
combining in an extruder a molten polymer selected from the group consisting of thermoplastic polyurethane elastomers and thermoplastic ethylene-vinyl acetate copolymers with (a) a physical or chemical blowing agent other than a supercritical fluid and (b) a supercritical fluid,wherein the blowing agent (a) is present in an amount up to about 15 wt % based on polymer weight and the supercritical fluid comprises one of about 0.1 to about 5 weight percent of supercritical CO2 based on polymer weight or about 0.1 to about 4 weight percent of supercritical N2 based on polymer weight, to form a mixture and
injection molding the mixture in a mold to form the low density foamed article, wherein the mold comprises a porous tool.