Patent ID: 7449517
Filing Date: 2008-11-11
Classification: C08J

Abstract:
1. An extruded composite building material, comprising: a thermoplastic resin material; a mixture of additive materials; a cellulosic material, wherein individual pieces of the cellulosic material are in the form of a chip having a size of −12 to +40 mesh, wherein the cellulosic material is dried, independent of the thermoplastic resin material, to 0.1% to 0.4% moisture by weight, and wherein the level of moisture of the cellulosic material is maintained until the cellulosic material is introduced into an extruder; wherein the thermoplastic resin material, the mixture of additive materials, and the cellulosic material are blended immediately prior to introduction into an extruder, to form a composite material, wherein the composite material comprises between 50% to 90% cellulosic material by weight, wherein the blended composite material is extruded to form the extruded composite building material, and wherein the mixture of additive materials comprises a blowing agent, which, when activated, acts to achieve density reduction in the composite building material, such that the composite building material has a density of between 0.4 and 0.8 sq.