Granted Patent
Utility
US 4,692,539 · App. 06/922,803
Pentaerythritol diphosphite stabilizers and process
Inventor:
John D. Spivack
Patented Case
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Granted: Sep 8, 1987
Filed: Oct 24, 1986
Inventor
John D. Spivack
Assignee (at issue)
Ciba-Geigy
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.