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:
Feb. 12, 1991
Filed:
Aug. 24, 1990
Raymond F Malon, St. Charles, MO (US);
Clint A Cruse, St. John, MO (US);
Permea, Inc., St. Louis, MO (US);
Abstract
A dope for forming membranes and the resulting asymmetric gas separation membranes are disclosed, the membranes having graded density skins which exhibit improved permeability characteristics and increased failure pressure strength. The membranes are produced from a process utilizing membrane forming dopes of complexing solvent systems formulated from two non-solvents and one or more solvents. The non-solvents are chosen one each, from non-solvents grouped according to non-solvent strength, i.e., one strong non-solvent and one weak non-solvent which are combined with one or more solvents in an acid:base complex solvent system for dissolving high weight percent total solids of membrane forming polymers. The process for forming the membranes is also disclosed.