| 摘要 |
PURPOSE:To provide a rigid urethane foam having excellent low-temperature dimensional stability even if the density is extremely low, and having excellent mechanical strength and heat-insulation, by reacting an organic polyisocyanate with a specific polyol. CONSTITUTION:The objective foam can be produced by reacting (A) an organic polyisocyanate with (B) a polyol comprising a combination of (i) a polyether polyol having a low OH-value (<=115, especially 80-115), (ii) an amine polyol having an OH-value of >=200 (especially 300-1,000) and (iii) a non-amine polyol having an OH-value of >=300 (especially 400-550) containing a sucrose polyether polyol as at least a part of (preferably 50-100wt% of) said polyol, in the presence of a foaming agent, and if necessary, catalyst and other assistant. The amounts of the polyol components are preferably 5-10% for (i), 50-85% for (ii) and 10-35% for (iii). The component (i) is preferably pentaerythritol compound, and the component (ii) is preferably (poly)arylene polyamine compound. |
