Granted Patent
Utility
US 4,472,575 · App. 06/452,806
Triphendioxazine dyestuffs
Inventor:
Andrew H. M. Renfrew
Patented Case
View Patent ↗
Granted: Sep 18, 1984
Filed: Dec 23, 1982
Inventor
Andrew H. M. Renfrew
Assignee (at issue)
IMPERIAL CHEMICAL INDUSTRIES LIMITED
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.