Process for preparing highly reactive (semi) crystalline and amorphous blocked polyisocyanates
CA 2352675 A1 · Owner: Weihrauch, Thomas · Inventors: Weihrauch, Thomas; Wenning, Andreas
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Disclosed is a solventless continuous process for preparing a mixture of (semi)crystalline and amphorous blocked polyisocyanates, by:, I reacting a mixture of (A) an aliphatic (cyclo)aliphatic or cycloaliphatic diisocyanate compound and (B) an aliphatic, (cyclo)aliphatic or cycloaliphatic polyisocyanate compound containing an isocyanurate group with a blocking agent that is (C) 1,2,4-triazine or (D) a pyrazole compound, in an extruder, intensive compounder intensive mixer, or static mixer by intensive commixing and short term reaction with a supply of heat, and, II isolating the resulting end product by rapid cooling.
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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 July 5, 2001. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended July 5, 2021.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 5, 2023.
- 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.