Granted Patent
Utility
US 4,256,802 · App. 06/127,478
Process for polyisocyanurate foams suitable for panels
Inventors:
Charles E. Koehler, Thomas R. McClellan, Pat L. Murray
Patented Case
View Patent ↗
Granted: Mar 17, 1981
Filed: Mar 5, 1980
Inventors
Charles E. Koehler
Thomas R. McClellan
Pat L. Murray
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.