Granted Patent
Utility
US 4,888,420 · App. 07/130,345
Water soluble cellulose acetate microspheres
Inventors:
Thomas L. Steiner, Dana T. Minnick, Kenneth A. Domeshek, Donald H. Lester, Jr.
Patented Case
View Patent ↗
Granted: Dec 19, 1989
Filed: Dec 8, 1987
Inventors
Thomas L. Steiner
Dana T. Minnick
Kenneth A. Domeshek
Donald H. Lester, Jr.
Assignee (at issue)
Celanese Fibers, Inc.
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.