Granted Patent
Utility
US 4,374,021 · App. 06/225,927
Method for controlling a pretreatment process
Inventor:
David B. Bartholic
Patented Case
View Patent ↗
Granted: Feb 15, 1983
Filed: Jan 19, 1981
Inventor
David B. Bartholic
Assignee (at issue)
Engelhard Minerals & Chemicals Corporation
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.