Rigid polyurethane foams with increased heat performance

Abstract

The present invention provides a rigid polyurethane foam made from the reaction product, at an isocyanate index of from about 90 to about 400, of a polyisocyanate, and a polyol component containing about 20 to about 80 wt. %, based on the weight of the polyol component, of a double metal cyanide (DMC)-catalyzed polyether polyol having a number average molecular weight of greater than about 1000 Daltons (Da), about 80 to about 20 wt. %, based on the weight of the polyol component, of a sucrose-based polyol having a functionality of from about 2.5 to about 6 and a molecular weight of from about 350 to less than about 1,000, and about 0 to about 40 wt. %, based on the weight of the polyol component, of a low molecular weight organic compound having a number average molecular weight of less than about 600 Da, in the presence of water, polyvinylchloride (PVC) particles having a diameter of from about 0.1 to about 200 microns, and glass beads having a diameter of from about 40 to about 400 microns (about 270 to about 45 mesh), and optionally, in the presence of at least one of carbon dioxide, surfactants, flame retardants, pigments and catalysts, wherein the rigid polyurethane foam with a density of about 10 to about 25 pcf has a heat sag measured at 102 mm overhang at 121° C. and one hour of less than about 8 mm. The inventive rigid polyurethane foams exhibit increased heat performance (decreased heat sag) while also maintaining impact and rebound strengths.