Patent ID: 6051174
Filing Date: 2000-04-18
Classification: B29C

Abstract:
A method comprising:providing a material to be foamed;mixing a supercritical fluid foaming agent into the material to create a mixture;creating a homogeneous single-phase solution from the mixture having a uniform concentration of foaming agent distributed therein and maintaining the single-phase solution at a pressure able to maintain the foaming agent in a supercritical state;nucleating the homogeneous single-phase solution by creating a rapid pressure drop in the single-phase solution at a pressure drop rate of at least about 0.18 Gpa/s (26,100 psi/s) to create a nucleated stream;shaping the nucleated stream essentially immediately after nucleating the solution to create a shaped microcellular extrudate; andreleasing the shaped microcellular extrudate into ambient conditions essentially immediately after shaping.