The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 05, 2003
Filed:
Aug. 09, 2000
Applicant:
Inventors:
Ligin Chen, West Roxbury, MA (US);
Kent Blizard, Ashland, MA (US);
Roland Kim, Somerville, MA (US);
Ted Burnham, Winchester, MA (US);
Assignee:
Trexel, Inc., Woburn, MA (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B29C 4/450 ;
U.S. Cl.
CPC ...
B29C 4/450 ;
Abstract
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.