PROCESS FOR PRODUCTION OF HARD POLYURETHANE FOAM

摘要

[PROBLEMS] To provide a process for producing a hard polyurethane foam for a thick heat-insulating material, which has an excellent curing property, which can be release-molded within a short period, and which is expanded with cyclopentane. [MEANS FOR SOLVING PROBLEMS] Disclosed is a process for producing a hard polyurethane foam for a thick heat-insulating material, which comprises reacting/expanding a polyisocyanate (A) and a polyol (B) in the presence of a catalyst (C) and a foaming agent (D), wherein the polyisocyanate (A) comprises a prepolymer (A1) having an isocyanate group therein and produced by reacting a polymeric MDI (A1-1) with a low-molecular-weight polyol (A1-2) having a side chain alkyl group therein and a foam-controlling agent (A2), wherein the polyol (B) comprises four types of polyether polyols (B1) to (B4), wherein the catalyst (C) comprises an urethane-forming catalyst (C1) and a trimerizing catalyst (C2), and wherein the foaming agent (D) comprises cyclopentane (D1) and water (D2).