Patent ID: 6623674
Filing Date: 2003-09-23
Classification: B29C,B32B,C08J,C09J,Y10T

Abstract:
A method of making a foam article comprising:(1) forming a mixture consisting essentially of at least one thermoplastic polymer and at least one blowing agent that is, or that produces, a fugitive gas in an amount greater than about 65 volume percent at Standard Pressure and Temperature per 100 volume percent polymer to form a foamable melt mixture, (2) shaping the melt mixture such that it has at least one major surface, (3) affixing or creating a barrier layer of nonfoaming material on one or more of said major surfaces, wherein the composition and thickness of the barrier layer inhibits diffusion of the fugitive gas out of the foamable melt mixture, and (4) causing the melt mixture to foam, wherein the density of the foam article is at least 20% less than would be the density of a similar foam article made without a barrier layer.