Sonoco Development Incorporated

Johannes Wim Van De Camp

Xiaokai Niu

David E Rhodes

Yanping Qiu

John F Whitehead

Garrett N Smith

Cliff Bellum

Tom T H Kim

Charles W Lounsbury, Jr

Nico J C Bessems

Emile Henricus Lutgens

Ed Spronk

Mark P Burns

Charles W Lounsbury

Tom T Kim

A wound paperboard tube having enhanced burst strength in high-moisture conditions up to and including complete and prolonged submersion in liquid water comprises a plurality of paperboard plies formed from a pulp comprising papermaking furnish and an effective amount of a size such that the paperboard plies have reduced moisture add-on when submerged in water, relative to paperboard plies formed from a pulp comprising the identical furnish but without the size. The plies are wound one upon another about an axis of the tube and adhered together with a water-resistant adhesive comprising a polyvinyl composition containing a cross-linking agent for inducing cross-linking of the adhesive.

Water-resistant wound paperboard tube

A winding core capable of being made in relatively thick-walled configurations and yet capable of being readily collapsed into a flattened configuration for shipping or storage prior to use comprises a plurality of fibrous plies helically wound one atop another and adhered together to form a tube. The plies are arranged in two or more groups of two or more plies each. The plies of each group are adhered to one another over at least a substantial majority of their facing surfaces, but the adjacent groups are non-adhered to each other over at least a substantial majority of their facing surfaces.

Collapsible winding core and method of making same

A tubular core and associated method of manufacture are provided. The tubular core includes at least one inner ply and at least two plastic plies disposed thereon. The inner ply, which can be paper or plastic, has an inner surface upon which identifying indicia are printed, for example, before the tube is formed and while the inner ply is in a flat configuration. The first and second plastic plies are disposed on the inner ply and adhered so that the second plastic ply substantially covers the inner ply and the first plastic ply.

Tubular core with polymer plies

Wide ply gaps are intentionally introduced into one or more plies in a radially intermediate zone of the wall of a spirally wound tube. Each ply having wide ply gaps is narrower than the width that would ordinarily be employed at a given spiral winding angle to achieve a butt joint between adjacent edges of consecutive turns of the ply, and the ply is wound at that given spiral winding angle in such a manner that gaps are defined between the adjacent edges of the consecutive turns of the ply. The wide ply gaps have the effect of increasing the compliance of the intermediate zone of the tube wall in the radial direction. Such increased radial compliance has been found to improve the ID stiffness of the tube relative to a tube constructed of the same materials but having no ply gaps in the intermediate zone.

Spirally wound tube with enhanced inner diameter stiffness, and method of making same

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Hartsville, SC, United States of America

Johannes Wim Van De Camp