Granted Patent
Utility
US 4,980,458 · App. 07/349,907
Mixed sodium, ammonium and/or calcium salt crystals of laked monoazo disulfonated pyrazolone pigments
Inventors:
Stefan Hari, Arnold Grubenmann, Andreas Burkhard
Patented Case
View Patent ↗
Granted: Dec 25, 1990
Filed: May 8, 1989
Inventors
Stefan Hari
Arnold Grubenmann
Andreas Burkhard
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.