Process for preparing continuously variable-composition copolymers
CA 2229366 C · Owner: Pierce, David Arthur · Inventors: Bollinger, Joseph Martin; Gore, Robert Howard; Pierce, David Arthur
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for the preparation of continuously variable-composition copolymers by effecting gradual changes in monomer composition during the polymerization is disclosed. Poly(meth)acrylate copolymers made by the process of the present invention have improved lubricating oil additive properties for, example, as pour point depressants when compared to related polymer additives made by conventional means.
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 February 13, 1998 and granted February 12, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended February 13, 2018.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by February 13, 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.