Granted Patent
Utility
US 5,089,568 · App. 07/256,338
Process of making thermoplastic copolymers containing polybenzoxazole, polybenzothiazole and polybenzimidazole moieties
Inventors:
William J. Harris, Wen-Fang Hwang
Patented Case
View Patent ↗
Granted: Feb 18, 1992
Filed: Oct 11, 1988
Inventors
William J. Harris
Wen-Fang Hwang
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.