Rigid urethane foam, insulation door and the heat-insulating main body of the refrigerator using a rigid urethane foam, method for producing a rigid urethane foam manufacturing for pre-mix the polyol and the insulating box or insulated door

摘要

PROBLEM TO BE SOLVED: To improve the thermal insulation of a refrigerator by raising the fluidity of a urethane raw material and filling urethane in a thermal insulating box interior of the refrigerator.SOLUTION: A hard urethane foam contains cyclopentane as a foaming agent, and has a thermal conductivity at 10°C of 18.0 to 19.0 mW/m K, and a bending strength at 10°C of 0.3 MPa, and has, in the case where an infrared absorption spectral peak intensity at 1,700 to 1,720 cmis represented as A1, and an infrared absorption spectral peak intensity at 1,590 to 1,610 cmis represented as A2, A1/A2 of 1.2 to 1.7. A premix polyol forms the hard urethane foam.