Granted Patent
Utility
US 5,258,441 · App. 07/887,600
Polyimide based friction material and preparation process of the material
Inventors:
Taizo Nagahiro, Noboru Umemoto
Patented Case
View Patent ↗
Granted: Nov 2, 1993
Filed: May 21, 1992
Inventors
Taizo Nagahiro
Noboru Umemoto
Assignees (at issue)
Mitsui Toatsu Chemicals, Incorporated
NTN-Rulon Corp.
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.