Granted Patent
Utility
US 4,650,880 · App. 06/811,215
Purification of substituted phthalic anhydrides
Inventor:
Avinash Kachhy
Patented Case
View Patent ↗
Granted: Mar 17, 1987
Filed: Dec 20, 1985
Inventor
Avinash Kachhy
Assignee (at issue)
Stauffer Chemical Company
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.