Abstract: A co-extruded multi-layer plastic pipe and method of manufacture are disclosed in which a first extruder melts and extrudes a first plastic material into the outer annulus of a coaxial extrusion die to form an outer pipe layer, and a second extruder melts and extrudes a highly oxidation-resistant plastic material into the inner annulus of said coaxial extrusion die under a blanket of inert gas to create an inner pipe layer, whereby the outer and inner pipe layers are fused together under the protection of the inert gas blanket which prevents premature degradation of the oxidation-resistant inner layer until the finished extruded pipe has cooled and solidified.

Abstract: An extruded composite structural artificial lumber product is manufactured from wood fiber and polyethylene, including recycled polyethylene, by reducing the wood fiber and polyethylene each to a finely divided particles, mechanically mixing the wood fiber and polyethylene particles together with a measured amount of a powdered endothermic foaming agent, mechanically mixing the mixture, without pre-pelletization, in a twin-screw extruder where it is compressed and heated until it becomes plastic and homogenous, and then extruding the plastic mixture, using vacuum to remove vaporized moisture and other excess volatiles, through a molding die which forms structural profile of the desired product.

Abstract: A deck system provides an easy to install deck by using unique columns, rails and planks. The columns can house electrical components. The rails enable quick assembly because they do not require additional fasteners or tools to install the balusters. The planks include a novel tongue-in-groove assembly that allows the planks to expand without damaging the deck.