Granted Patent
Utility
US 4,725,424 · App. 06/777,292
Process for producing carbon black
Inventors:
Mitsuru Tanaka, Takanori Uchida, Hideyuki Hisashi
Patented Case
View Patent ↗
Granted: Feb 16, 1988
Filed: Sep 18, 1985
Inventors
Mitsuru Tanaka
Takanori Uchida
Hideyuki Hisashi
Assignee (at issue)
Mitsubishi Chemical Industries, Ltd.
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.