Lubricant additive, lubricant additive composition, and lubricating oil composition containing the same
A lubricant additive includes a monoester carboxylic acid salt (A) represented by formula (1). In formula (1), R 1 represents a single bond between carbon atoms of carbonyl groups, or a divalent hydrocarbon group having 1 to 4 carbon atoms, and R 2 represents a hydrocarbon group having 1 to 22 carbon atoms. AO represents an oxyalkylene group of one type selected from oxyalkylene groups having 2 to 4 carbon atoms, or a mixed oxyalkylene group of two or more types selected from oxyalkylene groups having 2 to 4 carbon atoms, and n is an average number of added moles of the oxyalkylene group represented by AO and is 0 to 5. M represents organic ammonium.
1. A lubricant additive, comprising:
a monoester carboxylic acid salt (A) represented by formula (1),
wherein R 1 represents a divalent hydrocarbon group having 2 carbon atoms, R 2 represents a linear or branched saturated hydrocarbon group or a linear or branched unsaturated hydrocarbon group having 4 to 18 carbon atoms, AO represents an oxyalkylene group of one type selected from oxyalkylene groups having 2 to 3 carbon atoms, or a mixed oxyalkylene group of two or more types selected from oxyalkylene groups having 2 to 3 carbon atoms, n is an average number of added moles of the oxyalkylene group represented by AO and is 1 to 3, and M represents organic ammonium selected from the group of secondary and tertiary ammonium cations in which a saturated or unsaturated hydrocarbon group having 1 to 24 carbon atoms is bonded to a nitrogen atom.
2. A lubricant additive composition, comprising:
the lubricant additive according to claim 1 ; and
zinc dithiophosphate (B) represented by formula (2),
wherein R 3 to R 6 each independently represents a hydrocarbon group having 1 to 24 carbon atoms, wherein
(A):(B) being a mass ratio of the monoester carboxylic acid salt (A) to the zinc dithiophosphate (B) is 99:1 to 1:99.
3. A lubricating oil composition, comprising:
90 to 99.9 mass% of a lubricant base oil; and
0.1 to 10 mass% of the lubricant additive according to claim 1 .
4. A lubricating oil composition, comprising:
70 to 99.99 mass% of a lubricant base oil; and
0.01 to 30 mass% of the lubricant additive composition according to claim 2 .