CPC C10M 169/044 (2013.01) [C10M 101/02 (2013.01); C10M 129/54 (2013.01); C10M 145/14 (2013.01); C10M 149/10 (2013.01); C10M 155/00 (2013.01); C10M 157/10 (2013.01); C10M 161/00 (2013.01); C10M 2203/1006 (2013.01); C10M 2207/262 (2013.01); C10M 2209/084 (2013.01); C10M 2217/028 (2013.01); C10M 2229/00 (2013.01); C10N 2020/02 (2013.01); C10N 2020/04 (2013.01); C10N 2020/071 (2020.05); C10N 2030/02 (2013.01); C10N 2030/04 (2013.01); C10N 2040/25 (2013.01)] | 19 Claims |
1. A lubricating oil composition for an internal combustion engine, the composition consisting of:
(A) a lubricating base oil comprising at least one mineral base oil or at least one synthetic base oil or any combination thereof, and having a kinematic viscosity at 100° C. of 3.8 to 4.6 mm2/s;
(B) a metallic detergent comprising at least one metal salicylate detergent, wherein the component (B) is present in an amount of 1000 to 2000 mass ppm in terms of metal content on the basis of the total mass of the composition, and wherein the component (B) is present in an amount of no less than 10 mmol/kg in terms of total molar amount of any salicylate soap base per kilogram of the composition, and wherein the component (B) is overbased with at least one basic metal salt, wherein the at least one basic metal salt overbasing the component (B) consists of:
at least one first basic metal salt selected from the group consisting of at least one metal carbonate, at least one alkaline earth metal borate, and any combination thereof; and
optionally at least one second basic metal salt selected from the group consisting of at least one alkali metal hydroxide, at least one alkaline earth metal hydroxide, at least one alkali metal oxide, at least one alkaline earth metal oxide, and any combination thereof; and
at least one additive other than any metallic detergent, the at least one additive comprising:
(C) at least one comb-shaped poly(meth)acrylate in an amount of 1.0 to 4.0 mass % in terms of resin content on the basis of the total mass of the composition, the comb-shaped poly(meth)acrylate having a weight average molecular weight of 350,000 to 1,000,000 and a polydispersity index of no more than 4.0, wherein each said comb-shaped poly(meth)acrylate is obtained by polymerization of a monomer composition consisting of:
at least one poly(meth)acrylate macromonomer (M-6);
at least one monomer selected from the group consisting of
at least one monomer (M-1) represented by the following general formula (4), at least one monomer (M-2) represented by the following general formula (5), at least one monomer (M-3) represented by the following general formula (6), at least one monomer (M-4) represented by the following general formula (7), at least one monomer (M-5) represented by the following general formula (8), and any combination thereof,
wherein the macromonomer (M-6) is obtained via polymerizing:
at least one monomer selected from the group consisting of the monomers (M-1), (M-2), (M-3), and (M-4), and any combination thereof, and
optionally at least one said monomer (M-5),
and wherein the macromonomer (M-6) has a single polymerizable functional group in one molecule; and
(D) a succinimide dispersant in an amount of 100 to 1000 mass ppm in terms of nitrogen on the basis of the total mass of the composition, the component (D) comprising at least one non-modified succinimide dispersant or at least one boric acid-modified succinimide dispersant or any combination thereof, wherein a total nitrogen content derived from the non-modified succinimide dispersant and the boric acid-modified succinimide dispersant is no less than 70 mass % of a total nitrogen content of the component (D),
wherein the composition has HTHS viscosity at 150° C. of no less than 2.25 mPa·s and less than 2.55 mPa·s:
![]() wherein in the general formula (4), R3 represents a hydrogen atom or a methyl group; and R4 represents a linear or branched chain C1-5 alkyl group;
![]() wherein in the general formula (5), R5 represents a hydrogen atom or a methyl group; and R6 represents a linear or branched chain C6-18 alkyl group;
![]() wherein in the general formula (6), R7 represents a hydrogen atom or a methyl group; and R8 represents a linear or branched chain hydrocarbon alkyl group having a carbon number of no less than 19;
![]() wherein in the general formula (7), R9 represents a hydrogen atom or a methyl group; R10 represents a C1-18 alkylene group; E1 represents an amine residue having 1 to 2 nitrogen atoms and 0 to 2 oxygen atoms, or a heterocyclic residue having 1 to 2 nitrogen atoms and 0 to 2 oxygen atoms; and b represents 0 or 1; and
![]() wherein in the general formula (8), R11 represents a hydrogen atom or a methyl group; and E2 represents an amine residue having 1 to 2 nitrogen atoms and 0 to 2 oxygen atoms, or a heterocyclic residue having 1 to 2 nitrogen atoms and 0 to 2 oxygen atoms.
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