Granted Patent
Utility
US 4,335,218 · App. 06/201,137
Process for the preparation of a foam-cored laminate having metal facers and rigid polyisocyanurate foam core prepared in the presence of a dipolar aprotic organic solvent
Inventor:
David T. DeGuiseppi
Patented Case
View Patent ↗
Granted: Jun 15, 1982
Filed: Oct 27, 1980
Inventor
David T. DeGuiseppi
Assignee (at issue)
The Upjohn Co.
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.