Granted Patent
Utility
US 6,790,931 · App. 10/148,776
Method for producing sulfonated aromatic polymers and use of the process products for producing membranes
Inventors:
Wei Cui, Thomas Soczka-Guth, Georg Frank
Patented Case
View Patent ↗
Granted: Sep 14, 2004
Filed: Jan 13, 2003
Inventors
Wei Cui
Thomas Soczka-Guth
Georg Frank
Assignee (at issue)
Celanese Ventures GmbH
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.