Patent ID: 6638985
Filing Date: 2003-10-28
Classification: B29C,Y10T

Abstract:
A continuous method for making a foam material comprising:(1) mixing at least one amorphous thermoplastic polymeric material and at least one physical blowing agent in an apparatus having an exit shaping orifice at a temperature and pressure sufficient to form a melt solution wherein the blowing agent is uniformly distributed throughout the polymeric material; (2) reducing the temperature of the melt solution at the exit of the apparatus to an exit temperature that is less than 15Â° C. above the glass transition temperature of the neat polymeric material while maintaining the melt solution at a pressure sufficient to keep the blowing agent in solution; and (3) passing the solution through said exit shaping orifice and exposing the solution to atmospheric pressure, whereby the blowing agent expands causing nucleation and cell formation resulting in the melt solution foaming and solidifying at or about the time it exits the shaping orifice.