Granted Patent
Utility
US 4,874,848 · App. 06/873,436
Asymmetrical polyazo chromium complex dyes comprising resorcinol as a coupling component
Inventors:
Gerhard Back, Fabio Beffa
Patented Case
View Patent ↗
Granted: Oct 17, 1989
Filed: Jun 4, 1986
Inventors
Gerhard Back
Fabio Beffa
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.