Method for producing non-yellowing polyurethane urea foam
CA 2049833 A1 · Owner: Kato, Isao · Inventors: Kato, Isao; Morimoto, Kiyotake; Nakata, Masahiko
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A method for producing a non-yellowing polyurethane urea foam, which comprises reacting an isocyanate-terminated prepolymer obtained by the addition reaction of a polyol having a number average molecular weight of 100 to 5,000 and containing on the average 2 to 3 functional groups with an aliphatic polyisocyanate in an amount of 1.4 to 2.6 times the hydroxyl equivalent with water in an amount of 0.4 to 5 times the isocyanate equivalent in the presence of, per 100 parts by weight of the prepolymer, 0.1 to 5 parts by weight of a carboxylic acid metal salt or 0.1 to 10 parts by weight of an aminetype catalyst.
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 August 26, 1991. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended August 26, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by August 26, 2013.
- 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.