Extrusion process of polypropylene foam
CA 1190013 A · Owner: Sumitomo Chemical Co. Ltd. · Inventors: Sakakura, Kazuaki; Okumura, Takuzo; Fukushima, Nobuo
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for producing a highly expanded polypropylene foam uniform in the viscosity at the extrusion foaming, improved in melt strength and free from unevenness of surface by using a polypropylene resin having a specified melt tension.
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 July 9, 1985. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended July 9, 2002.
- 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.