Rigid polyurethane foams with improved properties

Abstract

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, in the presence of    c) a pentafluoropropane blowing agent, and    d) a catalyst.    
     
     
         2 . The process of  claim 1 , wherein said blowing agent is 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.  
     
     
         3 . The process of  claim 2 , wherein said sorbitol-based polyether polyol is an ethylene oxide, propylene oxide polyether polyol.  
     
     
         4 . The process of  claim 2 , wherein polyols which are not based on sorbitol are also included in the reaction mixture.  
     
     
         5 . The process of  claim 2 , wherein water is also included in the reaction mixture.  
     
     
         6 . and  7 . (Cancelled).  
     
     
         8 . 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, in the presence of    c) a pentafluoropropane blowing agent chosen from 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, and    d) a catalyst.    
     
     
         9 . The process of  claim 8 , wherein said sorbitol-based polyether polyol is an ethylene oxide, propylene oxide polyether polyol.  
     
     
         10 . The process of  claim 8 , wherein polyols which are not based on sorbitol are also included in the reaction mixture.  
     
     
         11 . The process of  claim 8 , wherein water is also included in the reaction mixture.