Granted Patent
Utility
US 5,047,591 · App. 07/241,828
Single-stage process for producing bis-(amino-nitrophenyl)-methane
Inventor:
Werner Stegmann
Patented Case
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Granted: Sep 10, 1991
Filed: Sep 6, 1988
Inventor
Werner Stegmann
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.