Granted Patent
Utility
US 4,289,906 · App. 06/101,544
Chemical process for preparing methylene bis-anilines
Inventor:
Kju H. Shin
Patented Case
View Patent ↗
Granted: Sep 15, 1981
Filed: Dec 10, 1979
Inventor
Kju H. Shin
Assignee (at issue)
Ethyl Corporation
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.