Granted Patent
Utility
US 4,940,759 · App. 07/325,629
Process for making film grade PVC
Inventor:
Yung-Chin Yang
Patented Case
View Patent ↗
Granted: Jul 10, 1990
Filed: Mar 20, 1989
Inventor
Yung-Chin Yang
Assignee (at issue)
B. F. Goodrich 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.