Use of N-(aminoalkyl) pyrrolidines as catalysts for the polyisocyanate polyaddition process

Abstract

The present invention relates to a process for preparing polyisocyanate polyaddition products by reacting (a) polyisocyanates with (b) relatively high molecular weight compounds containing at least two isocyanate-reactive hydrogen atoms and (c) chain-extending agents, in the presence of (d) N-(aminoalkyl)pyrrolidine catalysts corresponding to formula (I) in which R is a C 2-12 alkylene group (optionally containing O or N atoms but not isocyanate-reactive groups) and R′ is hydrogen or a C 1-4 alkyl group, (e) optionally, other known catalysts, and (f) other known additives.

What is claimed is:  
     
       1. A process for preparing a polyisocyanate polyaddition product comprising reacting 
       (a) a polyisocyanate with  
       (b) a relatively high molecular weight compound containing at least two isocyanate-reactive hydrogen atoms and  
       (c) a chain-extending agent, in the presence of  
       (d) an N-(aminoalkyl)pyrrolidine catalyst corresponding to the formula                    
       in which  
       R is a C 2-12  alkylene group (optionally containing O or N atoms but not isocyanate-reactive groups) and  
       R′ is hydrogen or  a C 1-4  alkyl group,  
       (e) optionally, other known catalysts, and  
       (f) other known additives.  
     
     
       2. A process according to  claim 1  wherein R is a 1,3-propylene group and R′ is hydrogen or  C 1-4  alkyl group. 
     
     
       3. A process according to  claim 1  wherein the N-(aminoalkyl)pyrrolidine catalyst is N-(3-aminopropyl)pyrrolidine and N-(3-(methylamino)propyl)pyrrolidine. 
     
     
       4. A process according to  claim 1  wherein the polyisocyanate polyaddition product is a cellular plastic.