| abstract |
Lubricating oil composition comprising a lubricating base oil, (A) an alkali metal or alkaline earth metal salicylate containing at least one type of compound selected from those represented by formula (1) below and / or a basic salt or overbased salicylate, (B) a phosphorus-containing antiwear agent, (C) an ashless dispersant selected from the group consisting of nitrogen-containing compounds having at least one branched or straight-chain alkyl or alkenyl group having 40 to 400 carbon atoms in the molecules, derivatives thereof and alkenyl succinimide boron modified products, and (D) an ashless antioxidant, as essential components, and containing boron in an amount of 0.01 to 0, 15 percent by mass and sulfur in a total amount of 0.3 percent by mass or less, based on the total mass of the composition: wherein R1 and R2 are each independently hydro gene or a secondary alkyl group having 10 to 40 carbon atoms, derived from polymers or copolymers of ethylene, propylene or 1-butene, at least any one of R1 or R2 is the secondary alkyl group having 10 to 40 atoms carbon, M is an alkali or alkaline earth metal, and n is an integer of 1 or 2 depending on the valence of the metal; and wherein component (B) is at least one compound selected from the group consisting of phosphorous compounds represented by formulas (3) and (4), metal salts of the phosphorous compounds and amine salts thereof. : wherein X1, X2 and X3 are each independently oxygen or sulfur, and R5, R6 and R7 are each independently hydrogen or a hydrocarbon group having 1 to 30 carbon atoms; and wherein X4, X5, X6 and X7 are each independently oxygen, or one or two of X4, X5 and X6 are a single bond or (poly) oxyalkylene group and the other (s) and X7 are Oxygen and R8, R9 and R10 are each independently hydrogen or a hydrocarbon group having 1 to 30 carbon atoms. |