Plastic piling

Abstract

As structural plastic pipe has an outer diameter of at least 10 inches and is suitable for use as a plastic piling. The pipe is at least 10 feet long and comprises an inner pipe core of no more than 6 inches in diameter. There is an outer, extruded, continuous, substantially homogeneous plastic layer at least two inches thick on substantially the entire length of the steel core. The plastic layer comprises low density polyethylene, high density polyethylene, polypropylene, foaming agent, and antioxidant, as well as a synergist for the antioxidant. The plastic layer is extruded directly onto the pipe core in a single extruding operation. A die head can be used for imparting rotational motion to an extruded plastic composition before it is introduced into a mold used for forming the plastic pipe to make certain that the entire mold is filled with the plastic composition.

Dependencies are inferred from the claim text.