Granted Patent
Utility
US 4,767,549 · App. 07/143,268
Dispersant coated mineral fiber in a drilling fluid
Inventors:
Terence D. McEwen, John D. Hansen
Patented Case
View Patent ↗
Granted: Aug 30, 1988
Filed: Jan 4, 1988
Inventors
Terence D. McEwen
John D. Hansen
Assignee (at issue)
USG INTERIORS, LLC
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.