| 摘要 |
PROBLEM TO BE SOLVED: To obtain a lubricating oil compsn. which is excellent in lubricity and thermal decomposition stability by compounding a lube base oil with a specific lubricating oil additive and a phenolic or amine antioxidant. SOLUTION: A lube base oil having a kinematic viscosity of 1-50 cSt at 100 deg.C and 10-1,000 cSt at 40 deg.C, a viscosity index of 70 or higher, pref. 100 or higher, an arom, content of 3-5 wt.%, pref. 1 wt.% or lower, and a sulfur and nitrogen content of 0.01 wt.% or lower, pref. 0.005 wt.% or lower, is compounded with 0.01-20 wt.%, pref. 0.05-15 wt.%, lubricating oil additive of the formula, 0.01-5 wt.%, pref. 0.05-3 wt.%, phenolic or aminic antioxidant, and optionally an oiliness improver, a, friction modifier, an extreme pressure agent, another antioxidant, a cleaning agent, a dispersant, a viscosity index improver, an antifoaming agent, a rust preventive, a flow point depressant, or the like. In the formula, R1 and R2 are each a 4C or higher hydrocarbon group; R3 is a hydrocarbon group; and (n) is 1 or higher, pref. 1-20.
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