Granted Patent
Utility
US 4,452,608 · App. 06/469,494
Process for the preparation of metal complex dye formulations using membrane separation
Inventor:
Paul Erzinger
Patented Case
View Patent ↗
Granted: Jun 5, 1984
Filed: Feb 24, 1983
Inventor
Paul Erzinger
Assignee (at issue)
Ciba-Geigy
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.