Method for producing a low density flexible polyurethane foam for a vehicle seat cushion

摘要

PROBLEM TO BE SOLVED: To produce a low-density flexible polyurethane foam excellent in impact resilience, mechanical strengths, and wet set by increasing the viscosity of a resin premix and by decreasing the degree of total unsaturation of a polyoxyalkylene polyol used. SOLUTION: This foam is produced by mixing a resin premix with an organic polyisocyanate. The resin premix contains a polyoxyalkylene polyol, a polymer polyol, water, a surfactant, and a catalyst and has a viscosity higher than 2.5 Pa.sec and lower than 4.5 Pa.sec. At least either the above polyoxyalkylene polyol or a polyoxyalkylene polyol used for producing the above polymer polyol has a degree of total unsaturation of 0.03 meq/g or lower, a functionality of 3 to 4, and a hydroxyl value of 20 to 40 mgKOH/g. A foam having a core density of 30 to 50 kg/m3, an impact resilience of 65 to 75, and a wet set of 5 to 15% is produced.