Granted Patent
Utility
US 5,219,981 · App. 07/663,332
Semi-continuous process for synthesis of polybenzazole polymers
Inventors:
Thomas D. Gregory, Carl W. Hurtig, Harvey D. Ledbetter, Kenneth J. Quackenbush, Steven Rosenberg
Patented Case
View Patent ↗
Granted: Jun 15, 1993
Filed: Mar 1, 1991
Inventors
Thomas D. Gregory
Carl W. Hurtig
Harvey D. Ledbetter
Kenneth J. Quackenbush
Steven Rosenberg
Assignee (at issue)
THE DOW CHEMICAL 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.