Granted Patent
Utility
US 6,380,352 · App. 09/812,581
Polyester precursor purification process
Inventors:
Charles Edwan Sumner, Jr., Ronald Buford Sheppard
Patented Case
View Patent ↗
Granted: Apr 30, 2002
Filed: Mar 20, 2001
Inventors
Charles Edwan Sumner, Jr.
Ronald Buford Sheppard
Assignee (at issue)
Eastman Chemical Company
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.