Granted Patent
Utility
US 4,292,254 · App. 06/197,848
Preparation of polyisocyanates from polycarbamates
Inventor:
John J. Leonard
Patented Case
View Patent ↗
Granted: Sep 29, 1981
Filed: Oct 17, 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.