Melt crystallization process for preparing high trans,trans-isomer containing 4,4'-diisocyanato dicyclohexylmethane
CA 2039544 A1 · Owner: Seneker, Stephen D. · Inventors: Dunlap, Kenneth L.; Potter, Terry A.; Lowery, Michael K.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Mo3399CIP, PU-374-CIP, MELT CRYSTALLIZATlON PROCESS FOR PREPARING HIGH TRANS,TRANS-ISOMER CONTAINING, 4,4'-DIISOCYANATO DICYCLOHEXYLMETHANE ABSTRACT OF THE DISCLOSURE, The present invention is directed for preparing a 4,4'-diisocyanato dicyclohexylmethane which contain a relatively high amount of the trans,trans-isomer. The process broadly comprises (a) melting a mixture of 4,4'-diisocyanato dicyclohexylmethane isomers, (b) cooling the melted mixture to form: (1) a liquid phase and, (2) a solid phase (c) removing said liquid phase, which is a commercially viable product itself, (d) heating the solid phase and removing that portion of the solid phase which has melted, and, (e) recovering …
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 April 2, 1991. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended April 2, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 2, 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.