S-alkylthiopropionic acids and derivatives
CA 2019769 C · Owner: Chisholm, Daniel R. · Inventors: Peveler, Richard D.; Flanagan, Mark E.; Fisch, Michael H.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
3-alkylthiopropionic acids are provided which are a direct addition reaction product of an alkylmercaptan and acrylic acid or an alkali metal salt thereof, the reaction being carried out by heating the reactants in the presence of an aqueous alkaline solution having a pH of at least about 11. The acids can be esterified with pentaerythritol in order to form tetraesters which are especially useful as stabilizers for polymer resins and polymers.
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 June 26, 1990 and granted January 26, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended June 26, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by June 26, 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.