Patent ID: 7018559

Claim:
A functional fluid composition that generates reduced levels of carboxylic acid during use comprising: (a) a base stock comprising a phosphate ester, and (b) at least one acid scavenger selected from (i) epoxides of the formula (ii) epoxides of the formula (iii) mixtures thereof; wherein R 1 , R 2 and R 3 are independently selected from H, and —C(O)—R 12 , and wherein one or two of R 1 , R 2 and R 3 are —C(O)—R 12 ; R 4 is selected from H or —CH 3 ; and R 5 , R 6 , R 7 and R 8 are independently selected from H, and —C(O)—R 12 , and wherein one or two of R 5 , R 6 , R 7 and R 8 are —C(O)—R 12 ; wherein; R 12 is an arylalkyl group having 7 to 12 carbon atoms.