Process for preparing polyisocyanates
CA 2446778 C · Owner: Wintermantel, Matthias · Inventors: Richter, Frank; Laas, Hans-Josef; Wintermantel, Matthias
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention relates to process for preparing a polyisocyanate comprising reacting a diisocyanate in the presence of an oligomerization catalyst , which is a compound prepared from an anion of pyrrole pyrazole, imidazole, 1,2,3- and 1,2,4-triazole a tetrazole, a substituted derivative thereof or a , carbocyclically or heterocyclically fused derivative thereof with a cation , which is , an alkali metal alkaline earth metal, monovalent ammonium or monovalent phosphonium cation. The invention overcomes the disadvantage of the processes of the state of the art which on the one hand use high-activity salt catalysts which , are suitable almost exclusively for generating trimers but hardly at …
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 7, 2002 and granted April 26, 2011. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 7, 2022.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 7, 2024.
- 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.