Process for the solvent-free, continuous preparation of polyureas
CA 2428342 A1 · Owner: Weihrauch, Thomas · Inventors: Behrendt, Klaus; Grenda, Werner; Weiss, Jorn Volker
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention relates to a solvent-free continuous process for the preparation of polyureas by reacting at least one isocyanate and/or isocyanurate having at least two NCO groups with at least one diamine and/or polyamine in an extruder, intensive kneader, intensive mixer or static mixer by thorough mixing and brief reaction with heat supply and subsequent isolation of the end product by cooling. By adopting this process, the reaction is shortened as compared with a batchwise process using a solvent.
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 May 8, 2003. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended May 8, 2023.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 8, 2025.
- 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.