Granted Patent
Utility
US 4,248,772 · App. 06/014,777
Positively or negatively charged azo compounds containing a ballasting group
Inventor:
William E. Long
Patented Case
View Patent ↗
Granted: Feb 3, 1981
Filed: Feb 23, 1979
Inventor
William E. Long
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.