Abstract: Disclosed is a polyol composition containing an aromatic polyester polyol having a hydroxyl number of 300-500 mgKOH/g and an average number of functional groups of 2.0-2.5, a medium-chain polyether polyol having a hydroxyl number of 100-250 mgKOH/g and an average number of functional groups of 2.0-4.0 and composed of a polyoxypropylene unit, and a long-chain polyether polyol having a hydroxyl number of 15-40 mgKOH/g, an average number of functional groups of 2.0-4.0 and an oxyethylene content of not more than 14% by weight and mainly composed of a polyoxypropylene unit.

Abstract: Disclosed is a polyol composition containing an aromatic polyester polyol having a hydroxyl number of 300-500 mgKOH/g and an average number of functional groups of 2.0-2.5, a medium-chain polyether polyol having a hydroxyl number of 100-250 mgKOH/g and an average number of functional groups of 2.0-4.0 and composed of a polyoxypropylene unit, and a long-chain polyether polyol having a hydroxyl number of 15-40 mgKOH/g, an average number of functional groups of 2.0-4.0 and an oxyethylene content of not more than 14% by weight and mainly composed of a polyoxypropylene unit.

Abstract: A method of producing a rigid urethane foam, which comprises reacting a blend polyol consisting of a polyol having a hydroxyl value of 300 to 450 mg KOH/g as prepared by using an acyclic sugar alcohol of 5 to 6 carbon atoms as an initiator and one or more other polyols, said blend polyol having a sugar alcohol content of 3 to 14 weight % and an average hydroxyl value of 300 to 430 mg KOH/g, with a polyisocyanate using 4.0 to 7.0 weight parts of water based on 100 weight parts of said polyol composition as a blowing agent, can reduce the CFC requirements by 50 to 100 percent as compared with the known production technology for rigid urethane foams and, moreover, the adhesive property of the resulting foam is not inferior to that of the conventional urethane foam.