A process for extrusion
CA 2255246 C · Owner: Union Carbide Chemicals & Plastics Technology Corporation · Inventors: Neubauer, Anthony Charles
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for the extrusion of polyethylene having a broad molecular weight distribution wherein the polyethylene is prepared in pellet form said extrusion taking place in a pelletizing extruder having one or more zones essentially filled with polyethylene and two or more zones partially filled with polyethylene including a feed zone comprising (i) introducing the polyethylene into the extruder at a temperature sufficient to melt the polyethylene; (ii) introducing a mixture of an inert gas and oxygen into at least one partially filled zone with the exception of the feed zone said mixture containing about 1 to about 21 percent by volume oxygen based on the volume of the gaseous mixture; …
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 December 8, 1998 and granted December 23, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 8, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 8, 2020.
- 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.