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:
Sep. 21, 1999
Filed:
Aug. 31, 1998
Y Paul Handa, Orleans, Ontario, CA;
Zhiyi Zhang, Vanier, Ontario, CA;
Other;
Abstract
The invention disclosed provides a method for producing ultramicrocellular polymer foams at low pressures. A polymer is saturated with a blowing agent at low temperatures and pressures within a short time period, due to retrograde vitrification. The blowing agent may be in the form of a gas or a volatile liquid. Polymer-blowing agent combinations are selected to provide a processing temperature/pressure in the area below the positive slope portion of the retrograde vitrification profile of the glass transition temperature of the polymer versus pressure. The polymer thus saturated has an exceptionally high blowing agent content, and is then foamed to produce materials with small cells and high cell density.