Gear oil compositions
CA 2052292 C · Owner: Eckert, Rudolf J. (Deceased) · Inventors: Eckert, Rudolf J. (Deceased); Loeffler, Donald E.; Rhodes, Robert B.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention provides gear oil compositions comprising a base oil and a hydrogenated star polymer comprising at least four arms, each arm comprising before hydrogenation, polymerised conjugated diene monomer units and having a weight average molecular weight in the range of from 3,000 to 15,000; a method of preparing said compositions; and the use of said hydrogenated star polymers as viscosity index improver additives in gear oil compositions.
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 September 26, 1991 and granted July 30, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended September 26, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 26, 2013.
- 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.