Granted Patent
Utility
US 6,428,582 · App. 08/592,898
Dye mixtures, 1:2 cobalt complex formazan dyes and their use
Inventors:
Urs Lehmann, Marcel Frick
Patented Case
View Patent ↗
Granted: Aug 6, 2002
Filed: Jan 29, 1996
Inventors
Urs Lehmann
Marcel Frick
Assignee (at issue)
Ciba Specialty Chemicals Corporation
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.