Diphosphonates as corrosion inhibitors for antifreeze coolants and other functional fluids
CA 2108601 C · Owner: Hirozawa, Stanley T. · Inventors: Welch, Michael Charles; Hirozawa, Stanley T.; Turcotte, David E.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A coolant or antifreeze composition has one or more glycols or glycol ethers in combination with water one or more additives, and an effective amount of one or more of the compounds 1-hydroxyoctylidene-1,1-diphosphonic acid 1-hydroxynonylidene-1,1- diphosphonic acid 1-hydroxydecylidene-1,1-diphosphonic acid 1- hydroxyundecylidene-1,1-diphosphonic acid and 1-hydroxy dodecylidene-1,1-diphosphonic acid as corrosion inhibitors.
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 October 18, 1993 and granted December 19, 2000. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 18, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 18, 2015.
- 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.