Granted Patent
Utility
US 4,994,544 · App. 07/431,779
Production process for polyimide fibers
Inventors:
Taizo Nagahiro, Masahiro Ohta, Shuichi Morikawa, Nubohito Koga, Shoji Tamai
Patented Case
View Patent ↗
Granted: Feb 19, 1991
Filed: Nov 6, 1989
Inventors
Taizo Nagahiro
Masahiro Ohta
Shuichi Morikawa
Nubohito Koga
Shoji Tamai
Assignee (at issue)
Mitsui Toatsu Chemicals, Incorporated
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.