Method for preventing coloration of diphenylmethane diisocyanate compound
CA 2111928 A1 · Owner: Nakano, Toshiaki · Inventors: Nakano, Toshiaki; Shimizu, Masato
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method for preventing the coloration of a diphenylmethane diisocyanate compound, which comprises adding, to the diphenylmethane diisocyanate compound, a hindered amine compound of the formula: (I), (I), wherein, R1 and R3 are, the same or different each a hydrogen atom or a C1-C8, hydrocarbon group R2 and R4 are, the same or different, each a C1-C8 hydrocarbon group R5 is a hydrogen atom, a methyl group, an ethyl group a phenoxymethyl group or, a phenyl group and, m is 0, 1 or 2, in an amount of 0.001 to 1.0 parts by weight per 100 parts by weight of the diphenylmethane diisocyanate compound. An excellent effect of preventing the coloration can be achieved only by the addition of a small …
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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 December 20, 1993. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended December 20, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 20, 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.