Granted Patent
Utility
US 5,177,135 · App. 07/621,497
.beta.-keto esters as stabilizers for chlorinated polymers
Inventors:
Wolfgang Wehner, Hermann O. Wirth
Patented Case
View Patent ↗
Granted: Jan 5, 1993
Filed: Dec 3, 1990
Inventors
Wolfgang Wehner
Hermann O. Wirth
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.