| 摘要 |
<p>[PROBLEMS] To provide a hard polyurethane foam which has good physical properties and a high oxygen index (30 or greater), and which meets the requirements of the standards for semi-non-combustible materials. [MEANS FOR SOLVING PROBLEMS] Disclosed is a process for producing a hard polyurethane foam, which comprises: subjecting an organic polyisocyanate (A) and water (B) to the urea-forming reaction and the isocyanurate-forming reaction in the presence of a flame-retardant agent (C) in an amount of 10 to 70 mass% relative to the total amount of the blend components, a foam-controlling agent (D) and a catalyst (E) comprising an isocyanurate-forming reaction catalyst, and in the presence or absence of a polyol in an amount of 5 mol% or less relative to the total amount of isocyanate reactive groups, under such conditions that the isocyanate index becomes 150 or greater as calculated by defining the isocyanate reactivity equivalence of water as 9, thereby expanding and curing the blended product.</p> |
