Granted Patent
Utility
US 4,491,481 · App. 06/189,878
Organic pigment compositions containing an azo compound with a heterocyclic substituent
Inventors:
George H. Robertson, David M. Price, Raymond N. Birrell
Patented Case
View Patent ↗
Granted: Jan 1, 1985
Filed: Sep 23, 1980
Inventors
George H. Robertson
David M. Price
Raymond N. Birrell
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.