Flame retardant blend containing monomeric and oligomeric flame retardants

Abstract

A flame retardant blend is disclosed that comprises: (a) a monomeric halogenated organic flame retardant that is adapted for use in a polyurethane foam formulation; and (b) an oligomeric organophosphate flame retardant having a phosphorus content of no less than about 10%, by weight, and at least three phosphate ester units therein, the amount of (a) in the blend being no less than the amount of (b). It is useful in polyurethane foams.

We claim:  
     
         1 . A flame retardant blend comprising: (a) a monomeric halogenated organic flame retardant that is adapted for use in a polyurethane foam formulation; and (b) an oligomeric organophosphate flame retardant having a phosphorus content of no less than about 10%, by weight, and at least three phosphate ester units therein, and being of the formula  
       
         
           
           
               
               
           
         
       
       where n, on a number average basis, can range from 2 to about 20, and R is selected from the group consisting of alkyl, haloalkyl and hydroxyalkyl and R′ is alkylene, the amount of (a) in the blend being no less than the amount of (b).  
     
     
         2 . A blend as claimed in  claim 1  wherein flame retardant (a) is a halogenated phosphate ester.  
     
     
         3 . A blend as claimed in  claim 1  wherein flame retardant (a) comprises a polybrominated diphenyl oxide.  
     
     
         4 . A blend as claimed in  claim 1  wherein flame retardant (a) is a halogenated phosphate ester and is present at from about 50% to about 95%, by weight of the blend.  
     
     
         5 . A blend as claimed in  claim 1  wherein flame retardant (a) is a polybrominated diphenyl oxide and is present at from about 50% to about 95%, by weight of the blend.  
     
     
         6 . A blend as claimed in any of claims  1 - 5  wherein R and R′ are ethyl and ethylene, respectively.