Granted Patent
Utility
US 4,243,583 · App. 06/042,696
Process for the preparation of azo dyes
Inventor:
Robert Portmann
Patented Case
View Patent ↗
Granted: Jan 6, 1981
Filed: May 25, 1979
Inventor
Robert Portmann
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.