Abstract: A composition and method for increasing the hydrolytic stability of a stabilizer composition comprising a first phosphite, a second phosphite, an optional phosphonite and an acid scavenger.

Abstract: A method is disclosed for increasing the hydrolytic stability of a stabilizer selected from the group consisting of (A) a first phosphite of the structure: and (B) a first phosphonite of the structure: wherein R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 are independently selected from the group consisting of hydrogen and alkyl, provided that at least one of R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 is alkyl, and n is 2; wherein said method comprises blending said stabilizer with (a) from about 1 to about 25 weight percent, based on the total weight of the resulting blend, of a second phosphite of the structure wherein R11, R12, R13, R14, and R15 are independently selected from the group consisting of hydrogen and alkyl, provided that at least one of R11, R12, R13, R14, and R15 is alkyl, and R16 and R17 are independently selected alkyl groups; and (b) from about 1 to about 10 weight percent, based on the total weight of the resulting blend, of an acid scavenger.