| 摘要 |
PROBLEM TO BE SOLVED: To provide a rigid polyurethane foam which uses water, HFC, HC and carbon dioxide as a foaming agent, and has a low density and a preferable size stability, has a high closed-cell ratio and is excellent in a performance of heat insulation or the like, by solving such a problem that it is difficult to obtain the foam having a satisfactory size stability and, in particular, it is difficult to obtain a foam having a satisfactory size stability at a low density and a high closed-cell ratio when producing the rigid polyurethane foam by using the foaming agent such as water, HFC and HC used in recent years as the foaming agent substituting for HCFC having the concern of destruction of ozone layer.SOLUTION: The rigid polyurethane foam is provided by reacting a polyol and a polyisocyanate in the presence of at least one of foaming agent selected from water, hydrofluorocarbon, hydrocarbon and carbon dioxide, a catalyst and a foam stabilizer, and has a density of 20 to 40 kg/m, a closed-cell ratio of 60 to 100% and the dimension changing rate of 10% or less. |
