Granted Patent
Utility
US 4,054,556 · App. 05/289,460
Polyurethanes cured with derivatives of 2,4-diamino-benzoic acid
Inventor:
Norman M. van Gulick
Patented Case
View Patent ↗
Granted: Oct 18, 1977
Filed: Sep 15, 1972
Inventor
Norman M. van Gulick
Assignee (at issue)
E.I. DU PONT DE NEMOURS AND 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.