Granted Patent
Utility
US 6,077,918 · App. 08/973,638
Polyarylene sulphides with polymer-bound phosphonium salts and process for producing them
Inventor:
Helmut Witteler
Patented Case
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Granted: Jun 20, 2000
Filed: Dec 23, 1997
Inventor
Helmut Witteler
Assignee (at issue)
Hoechst GmbH
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.