Granted Patent
Utility
US 5,114,893 · App. 07/608,816
Method of improving water-swellable clay properties by re-drying, compositions and articles
Inventor:
John Hughes
Patented Case
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Granted: May 19, 1992
Filed: Nov 5, 1990
Inventor
John Hughes
Assignee (at issue)
American Colloid Company
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.