Maleated high acid number high molecular weight polypropylene of low color
CA 2197791 C · Owner: Roberts, Thomas David · Inventors: Roberts, Thomas David; Coe, Stephen Wayne
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A novel, continuous process for the manufacture of novel higher molecular weight and higher acid numbered maleated polypropylenes with lower color at higher efficiencies involving specified ratios of polypropylene maleic anhydride, and free radical initiator is described. The novel maleated polypropylenes have an acid number greater than 4.5 a yellowness index color of no greater than 76 and a number average molecular weight of at least 20,000. The process entails continuously forming an intimate mixture of molten polypropylene and molten maleic anhydride at one end of a reactor continuously introducing a free radical initiator and continuously removing high acid number high molecular …
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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 August 18, 1995 and granted June 19, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 18, 2015.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 18, 2017.
- 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.