Oxidative stability of flexible polyurethane foams

Claim 1

In a method for improving the oxidative stability of flexible cellular polyurethanes prepared by reacting a polyol containing at least two active hydrogen atoms per molecule, as determined by the Zerewitinoff method, with a stoichiometric excess of a polyfunctional isocyanate, the reaction being conducted in the presence of water as a blowing agent, at least one tertiary amine blowing catalyst, and effective amount of a gel catalyst of the formula R a 1 SnX 4 -a, (R 3 1 Sn) 2 S, ##STR7## wherein X is a monovalent radical selected from the group consisting of ##STR8## chlorine and bromine, R 2 and R 3 each represents an alkyl radical containing between 1 and 20 carbon atoms, a cycloalkyl, phenylalkyl, alkylphenyl or a phenyl radical, R 4 represents an alkyl radical containing between 1 and 20 carbon atoms, a cycloalkyl, phenyl or a substituted phenyl radical, a represents the integer 1, 2 or 3 and n represents an integer between 1 and 12, inclusive, the improvement consisting essentially of employing a gel catalyst wherein R 1 is selected from the group consisting of methyl, allyl, phenyl, and substituted phenyl.