Patent ID: 7928045

Claim:
A lubricant composition comprising: (A) at least one lubricating oil selected from the group consisting of natural and synthetic lubricating base oils; (B) 0.1 to 5.0 weight percent based on the weight of the composition of at least one diphenylamine of the formula: wherein R 1 and R 2 are independently selected from the group consisting of hydrogen, alkyl of 1 to 12 carbon atoms, styryl, and α-alkyl styryl, provided that at least one of R 1 and R 2 is not hydrogen; and (C) 2,2′-thiobis(4-methyl-6-tert-butyl-phenol) wherein the weight ratio of the diphenylamine to 2,2′-thiobis(4-methyl-6-tert-butyl-phenol) is greater than 3:1.