Granted Patent
Utility
US 5,427,990 · App. 08/154,277
Method of Improving absorption of salt water by water-swellable clay by redrying
Inventor:
John Hughes
Patented Case
View Patent ↗
Granted: Jun 27, 1995
Filed: Nov 18, 1993
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.