Granted Patent
Utility
US 4,216,113 · App. 05/324,711
Process for preparing thickening grade of silica and process of using same
Inventor:
Milton E. Winyall
Patented Case
View Patent ↗
Granted: Aug 5, 1980
Filed: Jan 18, 1973
Inventor
Milton E. Winyall
Assignee (at issue)
W. R. Grace & Co.
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.