| 摘要 |
PROBLEM TO BE SOLVED: To provide a rigid polyurethane foam obtained by airless spray expansion using as a blowing agent carbon dioxide gas generated by a reaction of a polyisocyanate component with water and/or a hydrofluorocarbon(HFC) and excellent in spraying stability, workability and flame retardancy as well as excellent in dimensional stability against weathering. SOLUTION: The rigid polyurethane foam is obtained by airless spray expansion in which a polyisocyanate component is mixed in a mixing head with a formulation comprising a polyol component, a blowing agent, a catalyst and other auxiliary agents and caused to expand. As the blowing agent, is employed carbon dioxide gas generated by a reaction of a polyisocyanate component with water and/or a hydrofluorocarbon(HFC). The oxygen index (JIS K 7201) of the core portion is at least 22 and the core portion adapts to the rating 3 or higher of the flame retardancy according to JIS A 1321 at a thickness of 15-30 mm.
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