Granted Patent
Utility
US 4,877,906 · App. 07/276,275
Purification of polyols prepared using double metal cyanide complex catalysts
Inventor:
Stephen D. Harper
Patented Case
View Patent ↗
Granted: Oct 31, 1989
Filed: Nov 25, 1988
Inventor
Stephen D. Harper
Assignee (at issue)
Arco Chemical Technology, L.P.
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.