Flame resistant polyurethane foams - by reacting diphenylmethane polyisocyanate-4,4'-dihydrazinostilbene-2,2'-disulphinic acid reaction

摘要

Foam materials with carbodiimide groups are prepd. by reacting (I) a reaction product of a polyisocyanate of the diphenylmethane series with 1-10wt.% 4,41-dehydrazinostilbene-2,21-disulphonic acid, and opt. (II) an organic cpd. at least two active H atoms, with splitting out of carbon dioxide, in the presence of (III) a catalyst promoting the formation of carbodiimide groups. Gives foam materials with a good flame resistance and a good dimensional stability. Prolonged heating to cure the foam material is unnecessary.