Granted Patent
Utility
US 5,214,161 · App. 07/898,833
Preparation of polycyclic dyes
Inventor:
David J. Milner
Patented Case
View Patent ↗
Granted: May 25, 1993
Filed: Jun 15, 1992
Inventor
David J. Milner
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.