Granted Patent
Utility
US 4,986,977 · App. 07/449,589
Recovery of useful products from by-products of phosphate conversion coating process
Inventor:
Donald S. Peters
Patented Case
View Patent ↗
Granted: Jan 22, 1991
Filed: Dec 12, 1989
Inventor
Donald S. Peters
Assignee (at issue)
Man-Gill Chemical Company
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.