Granted Patent
Utility
US 4,933,437 · App. 07/029,363
Preparation of 1:2 chromium complex azo dyes asymmetrically substituted with solubilizing groups
Inventors:
Walter Iff, Daniel Parisot, Hans Schaller
Patented Case
View Patent ↗
Granted: Jun 12, 1990
Filed: Mar 23, 1987
Inventors
Walter Iff
Daniel Parisot
Hans Schaller
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.