Process of making lightweight, rigid polyurethane foam

摘要

In a process generating a polyurethane foam by forming a mixture including isocyanate and polyol reactants, catalyst, and blowing agent, which mixture reacts exothermically to yield a rigid polyurethane foam, there is included expandable polystyrene beads made of a polystyrene that has a softening point at or below the maximum temperature reached during the exothermic reaction.