Granted Patent
Utility
US 5,552,221 · App. 08/366,346
Polybenzazole fibers having improved tensile strength retention
Inventors:
Ying H. So, Steven J. Martin, Chieh-Chun Chau, Ritchie A. Wessling, Ashish Sen, Katsuhiko Kato, Daniel B. Roitman, Willie E. Rochefort
Patented Case
View Patent ↗
Granted: Sep 3, 1996
Filed: Dec 29, 1994
Inventors
Ying H. So
Steven J. Martin
Chieh-Chun Chau
Ritchie A. Wessling
Ashish Sen
Katsuhiko Kato
Daniel B. Roitman
Willie E. Rochefort
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.