Granted Patent
Utility
US 4,235,787 · App. 06/101,919
Benzophenone pentacarboxylic acids and their dianhydrides
Inventors:
Johann G. D. Schulz, Anatoli Onopchenko
Patented Case
View Patent ↗
Granted: Nov 25, 1980
Filed: Dec 10, 1979
Inventors
Johann G. D. Schulz
Anatoli Onopchenko
Assignee (at issue)
Gulf Research & Development Company
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.