Granted Patent
Utility
US 5,651,916 · App. 08/518,154
Process for the preparation of a propylene glycol antifreeze containing an alkali metal silicate
Inventor:
Thomas W. Weir
Patented Case
View Patent ↗
Granted: Jul 29, 1997
Filed: Aug 23, 1995
Inventor
Thomas W. Weir
Assignee (at issue)
Prestone Products 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.