Pactiv Corporation

Tenneco Packaging Inc.

Pregis Innovative Packaging LLC

Tenneco Protective Packaging, Inc.

Jeffrey J Stimler

Gary R Wilkes

Ronnie D Kisner

David P Zettel

Said K Farha

Kim A Bly

Eugene R Uhl

Harris A Dunbar

A method and apparatus for making a densified skin polymer foam plank comprising providing a polymer foam having a plurality of cells and heating an outer surface of the foam at a heating station. The heating step collapses and melts the cells adjacent the outer surface to form the densified skin having a density greater than a density of the foam before the heating step. Additionally, the method and apparatus may further include extruding the polymer foam from an extruder.

Polymer foam plank with densified skin, method and apparatus for producing a densified skin on a foam plank

A polymeric composition to be used in producing foam in which the polymeric composition comprises high density polyethylene, alkenyl aromatic polymer and a resiliency modifier resin. The high density polyethylene is in an amount of from about 5 to 45 weight percent of the polymeric composition. The high density polyethylene has a z-average molecular weight, M,, greater than about 1,000,000. The alkenyl aromatic polymer is in the amount of from about 3 to about 45 weight percent of the polymeric composition. The resiliency modifier resin is in the amount of from 10 to about 85 weight percent of the polymeric composition.

Foamable composition using high density polyethylene

A polymeric composition for producing foam in which the polymeric composition comprises high density polyethylene, alkenyl aromatic polymer and, optionally, a resiliency modifier resin. The high density polyethylene is in an amount of from about 45 to about 90 weight percent of the polymeric composition. The high density polyethylene has a z-average molecular weight, M.sub.z, greater than about 1,000,000. The alkenyl aromatic polymer is in the amount of from about 3 to about 45 weight percent of the polymeric composition. The resiliency modifier resin is in the amount of from 0 to about 40 weight percent of the polymeric composition. The foam is produced in the absence of a significant amount of a stability control agent.

A propylene homopolymer or copolymer, or a blend thereof, possessing both sufficient strain hardening, viscoelastic behavior, and melt ductility is heated, melted, and mixed in an extruder with an organic or inorganic physical blowing agent, or a mixture of organic and inorganic physical blowing agents, and with optional compatibilizing agents, nucleating agents, stabilizers and miscellaneous additives. This mixture is pressurized and, subsequently, is cooled to an appropriate temperature at an elevated pressure, and is extruded through a die at rates in excess of 1000 kg/hr to produce an expanded and dimensionally-stable, predominately closed cell propylene polymer foam with a density of between 10 kg/m.sup.3 and 150 kg/m.sup.3, and with a thickness in excess of 1.3 cm. The resultant foamed structure is characterized by a Foamability Index of greater than 1.9 and an Ebullition Time of less than 2.0.times.10.sup.-4 seconds.

Growing community of inventors

Queensbury, NY, United States of America

Jeffrey J Stimler