Granted Patent
Utility
US 5,189,181 · App. 07/817,615
Process for preparation 2,6-dihydrobenzo[1:26, 4:5-6]-difuran dyes
Inventors:
Nigel Hall, Nigel Hughes, Prakash Patel
Patented Case
View Patent ↗
Granted: Feb 23, 1993
Filed: Jan 7, 1992
Inventors
Nigel Hall
Nigel Hughes
Prakash Patel
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.