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:
Dec. 08, 1992
Filed:
Jun. 14, 1991
Gregory J Courval, Napanee, CA;
Symplastics Limited, Ontario, CA;
Abstract
In a solid state extrusion process a semi-crystalline polymer billet in a pressure chamber is forced through a die at the end of the chamber, with the polymer passing through the die at a temperature between 30.degree. C. below the alpha-crystalline temperature and the melting point of the polymer to form an oriented polymer profile. The pressure chamber is heated to about 0.50-0.95 of the melting point of the polymer and the die is heated to about 0.65-1.2 of the melting point of the polymer, with the die preferably being heated to at least 5.degree. C. warmer than the billet. A haul off stress on the profile extruded from the die is maintained between at least 0.5 MPa and a maximum amount without plastic deformation of the extrudate to obtain an oriented profile having a cross-sectional area greater than 0.5 cm.sup.2 at an extrusion rate greater than 0.5 m/min.