Granted Patent
Utility
US 4,443,496 · App. 06/400,820
Agent and method for modifying surface layer of cement structures
Inventors:
Masamichi Obitsu, Takahiro Hori, Toyoji Koinuma, Yuriko Sakaguchi
Patented Case
View Patent ↗
Granted: Apr 17, 1984
Filed: Jul 22, 1982
Inventors
Masamichi Obitsu
Takahiro Hori
Toyoji Koinuma
Yuriko Sakaguchi
Assignee (at issue)
NISSAN 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.