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US 6,376,059 B1Granted
Polyethylene foams and methods of their production
AssigneeTrexel, Inc.
InventorsJere R. Anderson, Kelvin T. Okamoto
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Abstract
High-density polyethylene (HDPE) foams that are essentially free of residual chemical blowing agents and reaction-by-products of chemical blowing agent are provided. The HDPE foams can be either microcellular foams or conventional foams. She foams can be produced in extrusion, injection molding, and blow molding processes that utilize a physical blowing agent. Specific die designs useful for making high quality foams are described.
Claims12
A method of forming a foam article comprising:
- conveying polymeric material in a downstream direction in a polymer processing apparatus, the polymeric material consisting essentially of high-density polyethylene;
- introducing a physical blowing agent into the polymeric material in the polymer processing apparatus;
- and
- forming a molded foam article from the polymeric material wherein the said polymeric material is essentially free of residual chemical blowing agents or by-products of chemical blowing agents.
1 more element
Dependencies are inferred from the claim text.