A process for the preparation of aqueous dispersions containing both blocked polyisocyanates and polyhydroxyl compounds
CA 2072931 C · Owner: Bayer Corporation · Inventors: Tirpak, Robin E.; Rosthauser, James W.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The present invention is directed to a process for the preparation of an aqueous dispersion containing both a blocked polyisocyanate and a polyhydroxyl compound by reacting an aqueously dispersed polyisocyanate having an isocyanate content of at least 12% by weight, based on the weight of the polyisocyanate, with a monofunctional blocking agent which is more reactive with isocyanate groups than water at an equivalent ratio of monofunctional blocking groups to isocyanate groups of 0.5:1 to 2:1 in the presence of a polyhydroxyl compound which is either water soluble or water dispersible, wherein the polyhydroxyl compound is present in an amount which is sufficient to provide an equivalent …
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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 2, 1992 and granted December 30, 2003. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended July 2, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by July 2, 2014.
- 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
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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.