Patent ID: 8912245

Claim:
A process for making a rigid foam comprising the step of reacting an organic polyisocyanate with a polyol blend at an isocyanate index of from 90 to 400 in the presence of a blowing agent wherein the polyol blend comprises a) 10 to 90 weight percent of a polyester polyol and b) the remainder of the polyol blend is at least one polyol having a functionality of 2 to 8 and a hydroxyl number of 200 to 1,200 wherein the polyester is the reaction product of a reaction mixture consisting essentially of: A) an aromatic component comprising 80 mole percent or greater of terephthalic acid; B) a polyethylene glycol having a molecular weight from 150 to 1000; and C) a glycol different from the glycol of B); wherein A, B, and C are provided in amounts in the reaction mixture on a percent weight bases of 20 to 60 weight percent A); 40 to 75 weight percent of B); and 5 to 35 weight percent of C) and the polyester polyol has a hydroxyl number of 200 to 400 and a viscosity of less than 5,000 mPa*s at 25° C. as measured by UNI EN IAO 3291.