Granted Patent
Utility
US 5,399,783 · App. 08/225,559
Preparation of 6,6'-dihydroxy-3,3,3',3'-tetramethyl-1,1'-spirobiindane
Inventors:
Mizuo Ito, Shigeru Iimuro
Patented Case
View Patent ↗
Granted: Mar 21, 1995
Filed: Apr 11, 1994
Inventors
Mizuo Ito
Shigeru Iimuro
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.