Granted Patent
Utility
US 4,190,718 · App. 05/581,375
Process for increasing molecular weight of vinylpyrrolidone polymer
Inventors:
Donald H. Lorenz, Earl P. Williams, Herman S. Schultz
Patented Case
View Patent ↗
Granted: Feb 26, 1980
Filed: May 27, 1975
Inventors
Donald H. Lorenz
Earl P. Williams
Herman S. Schultz
Assignee (at issue)
GAF Corporation
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.