Granted Patent
Utility
US 4,075,804 · App. 05/615,727
Fire resistant asbestos-free door, panel or building elements, and method of manufacture using unique compositions
Inventor:
Herbert E. Zimmerman
Patented Case
View Patent ↗
Granted: Feb 28, 1978
Filed: Sep 22, 1975
Inventor
Herbert E. Zimmerman
Assignee (at issue)
Champion International Corporation Limited
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.