Granted Patent
Utility
US 4,275,230 · App. 05/969,431
Purification of dicarboxylic acids
Inventor:
Peter Donaldson
Patented Case
View Patent ↗
Granted: Jun 23, 1981
Filed: Dec 14, 1978
Inventor
Peter Donaldson
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.