Granted Patent
Utility
US 4,380,565 · App. 06/338,020
Color preservation of wax-coated paperboard
Inventor:
Paul L. Krankkala
Patented Case
View Patent ↗
Granted: Apr 19, 1983
Filed: Jan 8, 1982
Inventor
Paul L. Krankkala
Assignee (at issue)
Champion International Corporation Limited
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.