Granted Patent
Utility
US 5,032,297 · App. 07/354,042
Enzymatically degradable fluid loss additive
Inventors:
Charles D. Williamson, Stephan J. Allenson, Robert K. Gabel, David A. Huddleston
Patented Case
View Patent ↗
Granted: Jul 16, 1991
Filed: May 19, 1989
Inventors
Charles D. Williamson
Stephan J. Allenson
Robert K. Gabel
David A. Huddleston
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.