Rigid polyurethane foams with improved properties
View Patent ↗In the process of the present invention, an organic polyisocyanate is reacted with a sorbitol-based polyether polyol having a number average molecular weight of from about 400 to about 1500, in the presence of a pentafluoropropane blowing agent, and a catalyst.
1. A process for preparing a rigid polyurethane foam comprising reacting:
a) an organic polyisocyanate with
b) a sorbitol-based polyether polyol having a number average molecular weight of from about 400 to about 1500,
b1) an o-toluene diamine-based polyether polyol,
b2) a polyester polyol, and
b3) water in the presence of
c) a pentafluoropropane blowing agent, selected from the group consisting of 1,1,2,2,3-pentafluoropropane, 1,1,2,3,3-pentafluoropropane, 1,1,1,2,3-pentafluoropropane and 1,1,1,3,3-pentafluoropropane,
d) a tertiary amine catalyst.
2. The process of claim 1 , wherein said sorbitol-based polyether polyol is an ethylene, propylene oxide polyether polyol.