Polyol compositions having good flow and water blown rigid polyurethane foams made thereby having good dimensional stability

Abstract

A polyol composition is provided which when reacted with and organic isocyanate, has good flow characteristics and makes an all water blown rigid polyurethane foam having good dimensional stability at low core densities of 1.1 pcf to 2.0 pcf. The polyol composition has a polyol component which must have present a polyoxyalkylene polyether polyol having an equivalent weight of 130 or less, an average functionality of 3.1 or greater, and a hydroxyl number of 400 or more, a polyoxyalkylene polyether polyol having an average functionality from 1.5 to 3.1 and a viscosity of less than 800 cP at 25.degree. C., and a polyoxyalkylene polyether polyol having an average functionality of greater than 3.1 and an equivalent weight of greater than 130. The polyol composition also has water as the blowing agent, and further contains a blow catalyst, a delayed action gel catalyst, and preferably a cure catalyst and a surfactant.

Dependencies are inferred from the claim text.