Granted Patent
Utility
US 5,223,626 · App. 07/437,719
Preparation of cationic alkylenediamine dye intermediates
Inventors:
Janos Vincze, Wilfried Herter
Patented Case
View Patent ↗
Granted: Jun 29, 1993
Filed: Nov 16, 1989
Inventors
Janos Vincze
Wilfried Herter
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.