Granted Patent
Utility
US 4,290,940 · App. 06/164,194
Pyrrole stabilizers for chlorine-containing thermoplastics
Inventors:
Hermann O. Wirth, Jurgen Bussing, Hans-Helmut Friedrich
Patented Case
View Patent ↗
Granted: Sep 22, 1981
Filed: Jun 30, 1980
Inventors
Hermann O. Wirth
Jurgen Bussing
Hans-Helmut Friedrich
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.