| 摘要 |
PROBLEM TO BE SOLVED: To obtain a rigid polyurethane foam having a high rate of closed cells and being excellent in dimensional stability, adhesion and demoldability by using a specified polyol without using any special shrinkage inhibitor even when a blowing agent entirely consisting of water is used in the production of a rigid polyurethane foam. SOLUTION: The production process is one for producing a rigid polyurethane foam by reacting a polyisocyanate with a polyol in the presence of a catalyst, a foam stabilizer and a blowing agent, wherein the polyol is a product obtained by effecting an addition reaction of a saccharide with an alkylene oxide in the presence of a catalyst and a solvent, the solvent used is a polyol having an average molecular weight of at least 300 and an average functionality of at least 3, and the solvent/saccharide mixing ratio is 100/(20-400) (by weight). The solvent/saccharide mixing ratio is desirably 100/(20-150) by weight. The solvent is more desirably a polyol having an average molecular weight of at least 300 and an average functionality of at least 5. |
