Granted Patent
Utility
US 5,086,841 · App. 07/656,437
Method of reducing circulation fluid loss using water absorbing polymer
Inventors:
Ansell L. Reid, Henry A. Grichuk
Patented Case
View Patent ↗
Granted: Feb 11, 1992
Filed: Feb 19, 1991
Inventors
Ansell L. Reid
Henry A. Grichuk
Assignee (at issue)
Nalco Chemical 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.