Importance

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Abstract

A tubular composite container includes a paperboard body ply wrapped into a tubular shape, and a polymer film liner ply wrapped into a tubular shape and adhered to the inner surface of the body ply. The liner ply has a circumferential length when unwrapped and flat that is less than that of the body ply so that the liner ply is substantially uncompressed circumferentially. A strip of polymer film liner material is wrapped onto a mandrel and overlapping edge portions of the liner strip are heat sealed together by first preheating the liner strip to a temperature below the sealing temperature of the heat seal material on the edge portions of the liner strip, and then further heating the overlap region of the liner strip to at least the sealing temperature to cause heat sealing of the edge portions. A paperboard strip is coated on an inner surface with adhesive and is then wrapped about the liner and adhered thereto. The outer surface of the liner strip is surface treated by corona discharge or flame treatment prior to being wrapped on the mandrel to improve adhesion to the paperboard, and the liner strip tension is maintained less than about 1 pound per inch of width to prevent liner stretching as the liner strip is advanced to and wrapped about the mandrel. The preheating of the liner strip is performed by a heated section of the mandrel over which the liner strip passes. The overlap region is locally heated by an infrared heater.

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First Claim