Flame retardant polyurethane foams

Abstract

The invention pertains to flame retardant polyurethane foams prepared by the reaction of a polyoxyalkylene polyether polyol with an organic polyisocyanate and a blowing agent wherein melamine is incorporated as the sole flame retardant compound. The amount of melamine may range from about 10 weight percent to about 55 weight percent of the total composition.

The embodiments of the invention in which an exclusive privilege or property is derived are defined as follows: 
     
       1. .[.The.]. .Iadd.A process for the .Iaddend.preparation of a flame-retardant flexible polyurethane foam consisting of reacting a polyoxyalkylene polyether polyol .Iadd.blend of (a) a glycerine or trimethylolpropane adduct containing ethylene oxide and propylene oxide, said adduct containing from about 5 to about 25 weight percent ethylene oxide and (b) a polyol containing from about 30 to about 60 weight percent of a 1:1 to 3:1 styrene to acrylonitrile graft polymer dispersion, said polyol blend .Iaddend.having an average equivalent weight of from about 500 to about 3000, .[.an organic polyisocyanate.]. .Iadd.toluene diisocyanate.Iaddend., a blowing agent, and a silicone surfactant .Iadd.to obtain a flame-retardant flexible polyurethane foam having a density of at least 1.62 pounds per cubic foot, .Iaddend.wherein dispersed in the polyether polyol .Iadd.blend .Iaddend.is melamine in the amount ranging from about 10 weight percent to about 55 weight percent of the total composition as the sole flame-retardant compound in the absence of a melamine dispersion stabilizer and wherein the melamine polyol dispersion is not crushed. 
     
     
       2. The .[.foam.]. .Iadd.process .Iaddend.of claim 1 wherein the polyether .Iadd.blend .Iaddend.polyol is a glycerine or trimethylolpropane adduct containing ethylene oxide and propylene oxide said polyol containing from about 5 to about 25 weight percent ethylene oxide. .[.3. The foam of claim 1 wherein the polyether polyol is a blend of the polyol of claim 2 and a polyol containing from about 30 to about 60 weight percent of a 1:1 to 3:1 
     
     
        styrene to acrylonitrile graft polymer dispersion..].4. The .[.foam.]. .Iadd.process .Iaddend.of claim .[.3.]. .Iadd.1 .Iaddend.wherein .[.the amount of.]. water .[.as.]. .Iadd.is .Iaddend.the blowing agent .Iadd.and .Iaddend.is .Iadd.present in an amount .Iaddend.less than about 2.5 weight 
     
     
        percent of the total composition. 5. The .[.foam.]. .Iadd.process .Iaddend.of claim .[.3.]. .Iadd.1 .Iaddend.wherein .[.the amount of.]. water .[.as.]. .Iadd.is .Iaddend.the blowing agent .Iadd.and .Iaddend.is .Iadd.present in an amount .Iaddend.less than 4.5 weight percent of the 
     
     
        total composition. 6. The .[.foam.]. .Iadd.process .Iaddend.of claim 5 wherein the polyether polyol .Iadd.blend .Iaddend.is an alkylene oxide adduct of trimethylolpropane containing at least 30 weight percent of from about 1:1 to about 3:1 styrene:acrylonitrile graft polymer dispersion. 
     
     
        .Iadd.7.  A flame-retardant flexible polyurethane foam which is the reaction product comprised of the reactants: (a) a polyether polyol blend of (i) glycerine or a trimethylolpropane adduct containing ethylene oxide and propylene oxide, said adduct containing from about 5 to about 25 weight percent ethylene oxide and (ii) a polyol containing from about 30 to about 60 weight percent of a 1:1 to 3:1 styrene to acrylonitrile graft polymer dispersion, said polyether polyol blend having an average equivalent weight of from about 500 to about 3000,   (b) toluene diisocyanate;   (c) a blowing agent; and   (d) a silicone surfactant, wherein dispersed in the polyether polyol blend is melamine in the amount ranging from about 10 weight percent to about 55 weight percent of the total composition as the sole flame retardant compound, and wherein the melamine polyol dispersion is not crushed. .Iaddend..Iadd.8. The foam as in claim 7, wherein the polyether polyol blend is glycerine or trimethylolpropane adduct containing ethylene oxide and propylene oxide, said polyol containing from about 5 to about 25 weight percent ethylene oxide. .Iaddend..Iadd.9. The foam as in claim 7 wherein water is the blowing agent and is present in an amount of less than about 2.5 weight percent of the total composition. .Iaddend..Iadd.10. The foam as in claim 7 wherein water is the blowing agent and is present in an amount of less than about 4.5 weight percent of the total composition. .Iaddend..Iadd.11. The foam as in claim 10, wherein the polyether polyol blend is an alkylene oxide adduct of trimethylolpropane containing at least 30 weight percent of from about 1:1 to about 3:1 styrene:acrylonitrile graft polymer dispersion. .Iaddend.