Thiophosphoric compositions, preparation and utilization of same as additives for lubricants

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 30, 1990 and granted April 23, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended March 30, 2010.
• A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by March 30, 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.