PROCESS FOR PREPARING RIDIG POLYISOCYANURATE FOAMS USING NATURAL-OIL POLYOLS

The present invention provides a process for producing a rigid polyisocyanurate foam involving reacting at an isocyanate index of from about 175 to about 400, a polyisocyanate with at least one natural-oil polyol containing at least about 35 wt. %, based on the weight of the polyol, of natural oil, having a hydroxyl number from about 175 to about 375 and a hydroxyl functionality of about 2.0 to about 2.8, in the presence of a blowing agent and optionally, in the presence of one or more of surfactants, flame retardants, pigments, catalysts and fillers, wherein the resulting foam has a renewable biobased content of at least 8% by weight. The foams provided by the inventive process possess properties similar to foams produced from petroleum-derived materials and may find use in wall or roof insulation systems. The high biobased content (>8%) may allow wall or roof insulation systems containing these foams to be considered for the U.S. Government's preferred procurement program.