Granted Patent
Utility
US 5,011,936 · App. 07/319,698
Process for refining 1,3-dimethyl-2-imidazolidinone
Inventors:
Tadashi Kobayashi, Mitsuo Wada, Shouzi Obuchi, Hiroshi Takayanagi
Patented Case
View Patent ↗
Granted: Apr 30, 1991
Filed: Mar 7, 1989
Inventors
Tadashi Kobayashi
Mitsuo Wada
Shouzi Obuchi
Hiroshi Takayanagi
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.