Granted Patent
Utility
US 4,647,593 · App. 06/869,540
Expandable polypropylene interpolymer particles
Inventors:
Kristine M. Bartosiak, Michael Knauff
Patented Case
View Patent ↗
Granted: Mar 3, 1987
Filed: Jun 2, 1986
Inventors
Kristine M. Bartosiak
Michael Knauff
Assignee (at issue)
Atlantic Richfield 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.