Non-round profiled pultruded tube

Abstract

A tubular article is formed of a spirally wound tube of paperboard. The paperboard tube has a circular cross-section at both its inner and outer surfaces. A shell of resin is pultruded onto the outer surface of the tube. Various resins can be used, including polyesters, vinyl esters, thermosetting epoxy resins, and others. The shell can optionally include reinforcing fibers, which can be short fibers or substantially continuous fibers oriented in various orientations relative to the paperboard tube. The reinforcing fibers can be in the form of rovings or fiber mats or woven fabrics. The shell's inner surface conforms to the circular outer surface of the tube and is intimately bonded thereto. The outer surface of the shell is defined by the pultrusion die to be non-circular in cross-section. Various non-circular shapes can be provided at the outer surface of the shell.

Dependencies are inferred from the claim text.