Vacuum pinning of molten thermoplastic film to a roughened casting roll
CA 1234958 A · Owner: E.I. Du Pont De Nemours And Company · Inventors: Heyer, David E.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process is disclosed for increasing the casting speed in manufacturing thermoplastic film and in increasing the quality of film made thereby. The film is cast, in molten form during manufacture by, means of a vacuum, onto a quench roll (casting roll) having a surface roughness of at least 3 microinches (0.08 micrometers).
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted April 12, 1988. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended April 12, 2005.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.