Granted Patent
Utility
US 4,290,968 · App. 06/171,522
Preparation of polyisocyanates from polycarbamates
Inventor:
John J. Leonard
Patented Case
View Patent ↗
Granted: Sep 22, 1981
Filed: Jul 23, 1980
Inventor
John J. Leonard
Assignee (at issue)
Atlantic Richfield 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.