A process for producing thermoformable foam sheet using a physical blowing agent
CA 2399438 C · Owner: Dow Global Technologies Inc. · Inventors: Welsh, Gary C.; Salmang, Roldolfo J.; Ballot, Michael M.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention is a process for producing a thermoplastic foam sheet comprising contacting a molten monovinylidene aromatic or olefinic polymer with a physical blowing agent to form a polymer/blowing agent mixture and , foaming the mixture into a region of lower pressure within a sheet extrusion line, wherein the extrudate is pulled and compressed to form a thermoplastic foam sheet having a uniform thickness of less than 3 mm.
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
- Filed January 12, 2001 and granted January 11, 2011. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended January 12, 2021.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 12, 2023.
- 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.