Graft copolymers and lubricants containing such as dispersant-viscosity improvers
CA 2029902 C · Owner: The Lubrizol Corporation · Inventors: Lange, Richard M.; Luciani, Carmen V.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A graft polymer is prepared by grafting onto a polymeric hydrocarbon backbone, a free-radical polymerizable vinyl nitrogen monomer, which grafting takes place in the presence of an aliphatic hydrocarbon substituted aromatic solvent capable of free-radical hydrogen atom chain transfer. The modified hydrocarbon based polymer finds utility as an additive for lubricating oils, particularly as dispersant-viscosity improvers for engine oils.
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 March 2, 1990 and granted July 13, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 2, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 2, 2012.
- 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.