Granted Patent
Utility
US 4,785,069 · App. 07/139,600
Preparation process of heat-resistant polymers from polycarboxylic acids or anhydrides in the presence of an alkali metal fluoride and quaternary onium salt
Inventors:
Masahiro Kouno, Akihiro Yamaguchi, Masanori Osawa, Kohei Shizuka, Hiromi Nakano, Kazumi Mizutani
Patented Case
View Patent ↗
Granted: Nov 15, 1988
Filed: Dec 29, 1987
Inventors
Masahiro Kouno
Akihiro Yamaguchi
Masanori Osawa
Kohei Shizuka
Hiromi Nakano
Kazumi Mizutani
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.