MANUFACTURE OF FLEXIBLE URETHANE FOAM

PURPOSE:To manufacture a flexible foam free from generation of cracks, by a method wherein the first class hydroxyl group density of polyol, the total consumption of amine and consumption of stannous octoate are specified and foam molding is performed by specifying a mold temperature at the time of initiation of reaction. CONSTITUTION:A flexible urethane foam is manufactured by making use of polyol, an amine catalyst, stannous octoate, water and appropriate auxiliary agent and polyisocyanate. In this instance, the first class hydroxyl group density of the polyol is made into at least 65 mol%. The total consumption of an amine catalyst is made into 1/40-1/15 times as much as of consumption of water at a weight ratio, consumption of the stannous octoate is made into 0.01-0.10 pts.wt. on the basis of 100 pts. wt. polyol, a mold temperature at the time of initiation of reaction is made into 50-70 deg.C and foam molding is performed. Polyol to be used is a chemical compound of water and polyhydroxy compound (for example, ethylene glycol or propylene glycol). Then the polyisocyanate to be used is, for example, 2, 4-tolylene diisocyanate or 2,6-tolylene diisocyanate.