Patent ID: 6197233
Filing Date: 2001-03-06
Classification: B29C,C08J

Abstract:
A method for producing an alkylene aromatic polymer or copolymer multistrand or coalesced strand foam, comprising the steps of:(a) providing a foamable composition comprising at least one polymer selected from the group consisting of alkylene aromatic polymers and alkylene aromatic copolymers and a blowing agent formulation,(b) extruding the composition through a die having a plurality of orifices,(c) foaming the extruded composition at a foaming temperature which is above the glass-transition temperature or the melting temperature of the polymer or coplymer,(d) maintaining the foaming product at an elevated temperature for a sufficient period of time to obtain adhesion between individual foam strands, and(e) allowing the foamed product to cool,characterized in that in steps (d) and (e) the temperature of the foam is controlled based on the thermodynamic nature of the blowing agent formulation wherein:the blowing agent formulation has a low evaporative cooling capacity and step (e) includes an accelerated cooling of the foamed product orthe blowing agent has a high evaporative cooling capacity and step (d) includes a transfer of additional heat to the foaming product.