Patent ID: 6440241
Filing Date: 2002-08-27
Classification: B29C

Abstract:
A method for producing a multilayer foam comprising the steps of:(a) providing at least one foamable composition comprising at least one polymer or copolymer and a blowing agent formulation, (b) extruding the foamable composition of step (a) through a die having a plurality of orifices, (c) foaming the extruded foamable composition of step (b) at a foaming temperature which is above the glass-transition temperature or the melting temperature of the polymer composition to make individual foaming layers, (d) maintaining the individual foaming layers of step (c) at an elevated temperature for a sufficient period of Time and contacting the individual foaming layers with each other to obtain adhesion between the individual foaming layers, and (e) allowing the product of step (d) to cool, wherein the plurality of orifices of step (b) comprises at least one orifice so designed that at least one monolithic foam layer extending across the whole breadth of the product of step (d) is produced, the first contact between the individual foaming layers according to step (d) is after step (b), and the product of step (e) has a density in the range from 16 to 80 kg/M3 and comprises a plurality of foam layers adhered directly to each other, wherein at least one of these foam layers is a monolithic foam layer extending across the whole breadth of the product of step (e).