High melt strength, ethylene polymer, process for making it, and use thereof
CA 2071779 C · Owner: Montell North America Inc. · Inventors: Denicola, Anthony J. Jr.; Mayfield, John W.; Mclaughlin, Thomas F.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Disclosed is a normally solid, high molecular weight gel-free, irradiated ethylene polymer having a density of from 0.89 to 0.97 g/cc characterized by high melt strength due to strain hardening which is believed to be caused by free-end long chain branches of the molecular chains forming the polymer. Also disclosed is a process for making the polymer by high energy radiation of a normally solid, high molecular weight ethylene, polymer in a reduced active oxygen environment maintaining the, irradiated material in such environment for a specific period of time, and then deactivating free radicals in the material.
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 June 22, 1992 and granted January 21, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 22, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 22, 2014.
- 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.