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.

Date of Patent:
Jun. 03, 2025

Filed:

Apr. 26, 2021
Applicant:

Nova Chemicals (International) S.a., Fribourg, CH;

Inventors:

Derek Wasylenko, Calgary, CA;

P. Scott Chisholm, Calgary, CA;

Tony Tikuisis, Calgary, CA;

Norman Aubee, Okotoks, CA;

Fraser Waldie, Calgary, CA;

Douglas Checknita, Calgary, CA;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B29C 48/30 (2019.01); B29C 48/00 (2019.01); B29K 105/00 (2006.01);
U.S. Cl.
CPC ...
B29C 48/3003 (2019.02); B29C 48/0018 (2019.02); B29K 2023/06 (2013.01); B29K 2105/0094 (2013.01);
Abstract

In the manufacture of extruded polymers there are a number of surface defects referred to as sharkskin, snakeskin and orange peel which all generally relate to the rheology of the polymer melt. A severe form of surface defect is 'melt fracture' which is believed to result when the shear rate at the surface of the polymer is sufficiently high that the surface of the polymer begins to fracture. That is, there is a slippage of the surface of the extruded polymer relative to the body of the polymer melt. The surface generally can't flow fast enough to keep up with the body of the extrudate and a fracture in the melt occurs generally resulting in a severe loss of surface properties for the extrudate. A polymer extension process is disclosed wherein these undesirable surface defects are eliminated.


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