Polyether urethane foam

Claim 1

A process for producing high resilience polyether urethane foam, said process comprising foaming and reacting a mixture comprising: I. organic polyol selected from the group consisting of (A) a polyether triol containing at least 40 mole per cent primary hydroxyl groups and having a molecular weight from about 2,000 to about 8,000 and (B) a mixture of said polyether triol and another polyether having an average of at least two hydroxyl groups, said polyether triol of said mixture amounting to at least 40 weight per cent of the total polyol content; Ii. organic polyisocyanate, said organic polyol and said polyisocyanate being present in the mixture in a major amount and in the relative amount required to produce the urethane; Iii. blowing agent in a minor amount sufficient to foam the reaction mixture; Iv. a catalytic amount of catalyst for the production of the urethane; and V. a cyanoalkoxy-alkyl modified siloxane fluid having the average formula (X).sub.z R.sub.3-z SiO(R.sub.2 SiO).sub.x [(X) (R)SiO].sub.y SiR.sub.3-z X.sub.z wherein x has a value of 2 to 6 inclusive; y has a value of 0 to 6 inclusive; z has a value of 0 to 1 inclusive; R is a lower alkyl or phenyl radical; and X is a cyanoalkoxy-alkyl radical having the formula --(O) n R'OR"CN where n has a value of 0 or 1, R' is an alkylene radical having from 3 to 8 carbon atoms and R" is an alkylene radical having from 2 to 4 carbon atoms said siloxane containing at least one of said cyanoalkoxy-alkyl radicals and having an average molecular weight in the range of about 400 to about 2000, in an amount sufficient to stabilize the foam against voids and shrinkage.