Granted Patent
Utility
US 4,294,987 · App. 06/108,522
Process for preparing methylene dianilines
Inventors:
Richard A. Prather, Nirad N. Shah
Patented Case
View Patent ↗
Granted: Oct 13, 1981
Filed: Dec 31, 1979
Inventors
Richard A. Prather
Nirad N. Shah
Assignee (at issue)
The Upjohn Co.
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.