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:
May. 09, 1989
Filed:
Oct. 14, 1987
Joseph L Feimer, Bright's Grove, CA;
Bernd A Koenitzer, Sarnia, CA;
Robert C Schucker, Baton Rouge, LA (US);
Exxon Research and Engineering Company, Florham Park, NJ (US);
Abstract
An anisotropic elastomeric membrane preferably made from polyurea/urethane has been prepared. These anisotropic membranes are made from the corresponding polymeric material by preparing the polymeric material in a good solvent containing less than 5 vol % non-solvent, producing a film of the polymer solution on a support with a maximum pore size less than 20 microns, subjecting the film to conditions such that the solvent vapor pressure-time factor is 1000 mm Hg-min. or less, preferably 200 mm Hg-min or less, most preferably approaching 0 mm Hg-min and quenching the membrane film in a non-solvent yielding a three-layered anisotropic membrane.