A process for the conditioning and/or purification of organic isocyanates
CA 2064929 C · Owner: Bayer Aktiengesellschaft · Inventors: Scholl, Hans-Joachim
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention relates to a process for the conditioning and/or purification of organic isocyanates by a) mixing organic isocyanates at 20 to 150°C with 0.001 to 1 mole %, based on the isocyanate, of a silylated acid corresponding to the formula, X-Si(CH3) n wherein, X represents the neutral acid residue obtained by removing the acidic hydrogen atoms from an n-basic acid having a pKa value of at most 3, with the exception of hydrohalic acids and, n is an integer from 1 to 3 and, b) optionally working up the resulting mixture by distillation after a residence time of at least 5 minutes.
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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 April 2, 1992 and granted June 11, 2002. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 2, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 2, 2014.
- 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.