Trexel, Inc.

Kent Blizard

Jere R Anderson

Kelvin Tsugio Okamoto

David Edward Pierick

Roland Y Kim

Srinath P Tupil

William Malavich

Richard S Straff

Ted Burnham

Ligin Chen

David Pierick

Kelvin Okamoto

A microcellular injection blow molding system and method, and microcellular blow molded articles produced thereby, are described. The system is equipped to extrude microcellular material that changes in thickness, material density, or both in the machine direction while maintaining a constant pressure drop rate during nucleation just prior to extrusion, providing the ability to produce consistent uniform microcellular material independent of material thickness. The systems and methods are particularly useful in production of strong, thin-walled, non-liquid-permeable, opaque containers that do not contain reinforcing agent, chromophore, or residue of chemical blowing agent or chemical blowing agent by-product.

Microcelluar extrusion/blow molding process and article made thereby

The invention provides a counter-rotating extrusion system for processing foam material. The system is designed to introduce a physical blowing agent into the extruder, thoroughly disperse the blowing agent within the polymer melt and, preferably, to maintain relatively high pressures downstream from the point of blowing agent introduction. High quality polymeric foams, including microcellular foams, can be produced using the extrusion system. The system is particularly suitable for the production of foams using shear sensitive and degradable materials, such as PVC.

Polymer processing system and apparatus

Systems and techniques for forming microcellular polymeric material, via injection molding, blow molding, continuous extrusion, or the like, at very low blowing agent levels, are described. The invention involves, in one aspect, the discovery of a region of very low blowing agent level where, surprisingly, microcellular material can be formed. Articles with particularly good surface properties are provided.

Polymer foam processing with low blowing agent levels

Semi-crystalline microcellular foams that include a midlevel amount of nucleating agent, and methods of their production, are provided. The microcellular foams can be produced in typical polymer processing techniques such as extrusion, injection molding and blow molding. The foams exhibit excellent mechanical properties and can be formed over a broad range of density into a number of different foam articles.

Microcellular articles and methods of their production

A polymeric foam article is comprised mainly of homopolymeric polypropylene, or unimodal polypropylene. The polymeric article can be microcellular, and can be formed into a drinking straw.

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Ashland, MA, United States of America

Kent Blizard