| 摘要 |
PROBLEM TO BE SOLVED: To provide a rust-preventive oil composition which has a sufficiently high rust-preventiveness as well as a satisfactorily high safety to human bodies or ecological system even without using a barium- or zinc-based rust-preventive or a tarnishing agent such as an alkyleneoxide adduct of alkyl phenols. SOLUTION: The rust-preventive oil composition contains 1-10% by mass, based on the composition total quantity, of such a sulfonate as an alkali metal sulfonate in the base oil; has contents of barium, zinc, chlorine and lead each of in the terms of the elements of less than 1,000 ppm by mass on the basis of the composition total quantity, has a content of the compound having the group expressed by formula (1) (wherein, R<1> is a 1-24C alkyl group; R<2> is a 2-4C alkylene group; m is an integer of 1-5; and n is an integer of 1-6) of less than 1,000 ppm by mass on the basis of the total composition quantity; has a total basicity of 1-20 mgKOH/g; and has a condition, concerning the above sulfonate content and the above total basicity, satisfying formula (2): TBN/Cs <=3 [wherein, Cs is a content (% by mass) of an sulfonic acid; and TBN is a total basicity (mg KOH/g)]. |
