Polymethylene polyphenyl polyisocyanate based prepolymers
CA 2094554 C · Owner: Basf Corporation · Inventors: Narayan, Thirumurti
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
This invention is a liquid polyisocyanate prepolymer comprising the reaction product of an organic polyisocyanate blend and a polyoxyalkylene polyol, where polyisocyanate blend is A) a diphenylmethane diisocyanate comprising from 50 weight percent to 95 weight percent 4,4'-diphenylmethane diisocyanate, from 5 weight percent to 50 weight percent 2,4'-diphenylmethane diisocyanate, and less than 10 weight percent 2,2'-diphenylmethane diisocyanate said, weight percentages based on the total weight of the ingredients in A);, B) a polymethylene polyphenyl polyisocyanate comprising from 30 weight percent to 70 weight percent diphenylmethane diisocyanate, the remainder comprising polymethylene …
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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 April 21, 1993 and granted December 25, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended April 21, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 21, 2015.
- 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.