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:
Aug. 19, 1997
Filed:
May. 07, 1996
Applicant:
Inventors:
John E Cadotte, Minnetonka, MN (US);
Daniel A Batzel, Glenview, IL (US);
Thomas F Stocker, San Diego, CA (US);
Assignee:
The Dow Chemical Company, Midland, MI (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B01D / ;
U.S. Cl.
CPC ...
21050038 ; 21050037 ; 210490 ; 264 451 ; 264 48 ;
Abstract
To prevent the deterioration of the flux and salt rejection characteristics of polyamide, thin-film, composite reverse osmosis membranes when subjected to relatively high temperature drying conditions, an unsubstituted inorganic ammonium cation salt of an acid is incorporated into the process of manufacture. The ammonium salt can be introduced into the process either before or after the membrane is formed by interfacial polymerization so long as it is added before the membrane is heated.