Liquid polyisocyanate mixtures, a process for their preparation, and their use in the preparation of polyurethane foams
CA 2023641 C · Owner: Gupta, Pramod · Inventors: Gupta, Pramod; Gebauer, Herbert; Wiedermann, Rolf
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
This invention relates to novel urethane-modified polyisocyanate mixtures of the diphenylmethane series prepared by a process comprising reacting polyisocyanates or polyisocyanate mixtures of the diphenylmethane series with certain monohydric and/or polyhydric alcohols and optionally, subsequently mixing the initially modified products with polyisocyanates or polyisocyanate mixtures of the diphenylmethane series that have not been modified with urethane groups. This invention further relates to the use of the polyisocyanate mixtures in the preparation of polyurethane foams.
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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 August 20, 1990 and granted May 15, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended August 20, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 20, 2012.
- 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.