Patent ID: 6860953

Claim:
A process for manufacturing a backing material for a floor covering comprising the steps of: chopping a mixture of waste polymeric material wherein the waste polymeric material has about 0.1 to 40 percent aliphatic polyamide material having a predetermined melting temperature; granulating the chopped mixture into fragments that are smaller than the original size of the waste polymeric material; densifying the granulated mixture into pelletized waste polymeric material; mixing the waste polymeric material with a blowing agent having a predetermined decomposition temperature; extruding the mixed waste polymeric material and blowing agent at a temperature less than the melting temperature of a majority of the aliphatic polyamide material and less than the decomposition temperature of the blowing agent to form an extrudate; calendering the extrudate to form a backing sheet; adhering the backing sheet to the floor covering; and heating the backing sheet to a temperature above the decomposition temperature of the blowing agent, thereby causing the backing sheet to expand to form a cushioned backing layer.