Granted Patent
Utility
US 5,770,643 · App. 08/618,591
Pyrrolodiazine derivatives as stabilizers for chlorine-containing polymers
Inventors:
Wolfgang Wehner, Hans-Helmut Friedrich, Rolf Drewes
Patented Case
View Patent ↗
Granted: Jun 23, 1998
Filed: Mar 20, 1996
Inventors
Wolfgang Wehner
Hans-Helmut Friedrich
Rolf Drewes
Assignee (at issue)
Ciba Specialty Chemicals Corporation
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.