FLEXIBLE POLYURETHANE FOAM AND ITS PRODUCTION

PROBLEM TO BE SOLVED: To obtain a high-hardness flexible polyurethane foam by using a polyoxyalkylene polyol having a low ratio of the content of hydroxyl groups derived from a monool to the total hydroxyl group content and a high degree of selectivity of head-to-tail bonding of oxypropylene units. SOLUTION: In a process for producing a flexible polyurethane foam from a polyoxyalkylene polyol and a polyisocyanate compd., the polyol used has a degree of selectivity of head-to-tail bonding in propylene oxide polymn. of 96mol% or higher. The polyol has a hydroxyl value higher than 35mgkOH/g but not higher than 50mgkOH/g and a content of hydroxyl groups derived from a monool of 2.5% or lower of the total hydroxyl group content, or has a hydroxyl value higher than 50mgkOH/g but not higher than 60mgkOH/g and a content of hydroxyl groups derived from a monool of 1.5% or lower of the total hydroxyl group content, or has a hydoxyl value higher than 60 mgkOH/g but not higher than 70mgkOH/g and a content of hydroxyl groups derived from a monool of 0.8% or lower of the total hydroxyl group content.