Polyol composition having good flow and formic acid blown rigid polyurethane foams made thereby having good dimensional stability

摘要

A polyol composition is provided which when reacted with an organic isocyanate, has good flow characteristics and makes a rigid polyurethane foam having good dimensional stability at low densities. The polyol composition has a polyol component which must have present a polyoxyalkylene polyether polyol having an equivalent weight of 130 or less 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° C., and a polyoxyalkylene polyether polyol having an average functionality of greater than 3.1 and a viscosity of 5, 000 cp or less at 25° C. The polyol composition also has formic acid or a mixture of formic acid and water as blowing agents, and further contains a delayed action blow catalyst and a delayed action gel catalyst.