NIKE, Inc.
Bead foam compression molding method with in situ steam generation for low density product

Abstract:

Disclosed is a method for molding a foamed article, such as a midsole or outsole for footwear, in which first water, then a desired amount of thermoplastic polyurethane foam beads are placed in a compression mold in the shape of the article and the mold is brought to a peak temperature of from about 130.degree. C. to about 180.degree. C. over a period of from about 300 to about 1500 seconds, then cooled to from about 5.degree. C. to about 80.degree. C. over a period of from about 300 to about 1500 seconds within about 30 seconds after the peak temperature is reached. The foamed article made by the method has a density of from about 0.1 to about 0.45 g/cm.sup.3.