Granted Patent
Utility
US 4,634,538 · App. 06/749,663
Water swellable clay composition and method to maintain stability in salt contaminated water
Inventor:
William Alexander
Patented Case
View Patent ↗
Granted: Jan 6, 1987
Filed: Jun 28, 1985
Inventor
William Alexander
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.