Granted Patent
Utility
US 4,391,637 · App. 06/313,031
Rheological additive for non-aqueous fluid systems
Inventors:
Wilbur Mardis, Claude M. Finlayson
Patented Case
View Patent ↗
Granted: Jul 5, 1983
Filed: Oct 19, 1981
Inventors
Wilbur Mardis
Claude M. Finlayson
Assignee (at issue)
NL Industries, Inc.
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.