Granted Patent
Utility
US 4,208,218 · App. 05/890,809
Viscosity increasing additive for non-aqueous fluid systems
Inventor:
Claude M. Finlayson
Patented Case
View Patent ↗
Granted: Jun 17, 1980
Filed: Mar 27, 1978
Inventor
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.