Patent ID: 7300961

Claim:
A process for preparing a low density, solely water-blown rigid polyurethane foam consisting of reacting: (1) a polyol composition composed of: 1.) at least 30% by weight, based on the total weight of the polyol composition, of at least one aromatic amine-initiated polyether polyol having a hydroxyl number of from greater than 200 to about 405; and 2.) at least one of the following: (i) up to 50% by weight, based on the total weight of the polyol composition of a polyether polyol having a functionality greater than or equal to 2.5 which is different from the polyether polyol of 1.); and (ii) up to 70% by weight, based on the total weight of the polyol composition, of a polyester polyol; with (2) at least one isocyanate; in the presence of (3) optionally, at least one catalyst; (4) water; and (5) optionally, at least one additive or auxiliary agent selected from internal mold release agents, pigments, cell regulators, flame retarding agents, plasticizers, dyes, fillers or reinforcing agents wherein the low density, solely water-blown rigid polyurethane foam produced has a closed cell content of at least 80%.