Use of low triphenylphosphate, high phosphorous content isopropyl phenyl phosphates as flame retardants in polyurethane or polyisocyanurate foams

A polyurethane or polyisocyanurate foam composition comprising at least one isocyanate, polyol, or combination thereof, and a flame retarding amount of an alkylated triaryl phosphate ester, wherein said alkylated triaryl phosphate ester contains greater than about 75 wt % monalkylphenyl diphenyl phosphates, less than about 1 wt % triphenyl phosphate (“TPP”) and in the range of from about 5 to about 10 wt % organic phosphorous content, all based on the total weight of the alkylated triaryl phosphate ester wherein said alkylated triary phosphate ester is an isopropylphenyl diphenyl phosphate ester comprising:

• b) isopropylphenyl diphenyl phosphate esters comprising in the range of from about 63 to 99.9 wt % 2-isopropylphenyl phosphate (2-IPP), in the range of from about 0.1 to 4-wt % 3-isopropylphenyl phosphate (3-IPP), and in the range of from about 0.1 to 40 wt % 4-isopropylphenyl phosphate (4-IPP), wherein all wt. % are based on the total weight of the isopropylphenyl diphenyl phosphate ester.