Uretdione diisocyanates and a process for their production
CA 2196027 A1 · Owner: Laas, Hans-Josef · Inventors: Pedain, Josef; Halpaap, Reinhard; Konig, Klaus
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 preparing pure bis(isocyanatoalkyl)-monouretdiones corresponding to formula (I) (see fig. I) (I), wherein, R represents identical or different linear or branched alkyl groups having 4 to 9 carbon atoms, by oligomerizing at least a portion of the isocyanate groups of aliphatic diisocyanates in the presence of catalysts which accelerate the dimerization of isocyanate groups, terminating the reaction at the desired degree of oligomerization removing unreacted excess diisocyanate by extraction or thin film distillation to obtain a distillation residue, subjecting the distillation residue to thin film distillation at a temperature of 160 to 220°C …
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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 January 27, 1997. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended January 27, 2017.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by January 27, 2019.
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Timeline
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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.