RIGID POLYURETHANE FOAMS WITH LOW THERMAL CONDUCTIVITY AND A PROCESS FOR THEIR PRODUCTION

摘要

A rigid polyurethane foam having low thermal conductivity is provided to obtain polyurethane foam having a low k-factor and useful for manufacturing refrigerator systems and other applications requiring excellent insulation property. A rigid closed-cell polyurethane foam is obtained by reacting: (a) an isocyanate-reactive component containing (1) an amine-initiated polyether polyol and (2) polyester polyol; and (b) a diisocyanate or polyisocyanate, in the presence of (c) a hydrofluorocarbon foaming agent, and (d) a catalyst by using water in an amount of less than 0.3 wt% based on the total foam-forming mixture, and has a density of 2.0-4.0 lb/ft^3.