The present invention provides an acrylate-based copolymer obtained by polymerizing constituent monomers including a polymerizable monomer (a) consisting of an alkyl acrylate-based monomer represented by the following general formula (1) in an amount of from 10 mol % to 95 mol % with respect to a total number of moles of the constituent monomers, a polymerizable monomer (b) consisting of an alkylene glycol acrylate-based monomer represented by the following general formula (2) in an amount of from 5 mol % to 50 mol % with respect to the total number of moles of the constituent monomers, and at least one kind of polymerizable monomer (c) selected from the group consisting of an aromatic vinyl-based monomer (c-1) and a short-chain alkyl acrylate-based monomer (c-2) represented by the following general formula (3) in an amount of from 0 mol % to 60 mol % with respect to the total number of moles of the constituent monomers. In the formula (1), R.sup.1 represents an alkyl group having 4 to 18 carbon atoms, and Al represents a hydrogen atom. In the formula (2), R.sup.2 represents an alkylene group having 2 to 4 carbon atoms, R.sup.3 represents a hydrogen atom or an alkyl group having 1 to 30 carbon atoms, A.sup.2 represents a hydrogen atom, and “n” represents a number from 2 to 20. In the formula (3), R.sup.4 represents an alkyl group having 1 to 3 carbon atoms, and A.sup.3 represents a hydrogen atom.

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A comb copolymer viscosity modifier may be made by polymerization comprising at least, or consisting essentially of, the following monomers: (a) a hydrogenated polybutadiene-based (alk)acrylate ester macromonomer (which repeat units may comprise from 7.0 wt % to 18 wt % of the repeat units of the comb copolymer viscosity modifier); (b) a C.sub.3-C.sub.8 alkyl (alk)acrylate ester monomer (which repeat units may comprise from 40 wt % to 71 wt % or from 45 wt % to 64 wt % of the repeat units of the comb copolymer viscosity modifier); and (c) a C.sub.12-C.sub.24 alkyl (alk)acrylate ester monomer, wherein repeat units based on the C.sub.12-C.sub.24 alkyl (alk)acrylate ester monomer comprise at least 21.0 wt % (and optionally up to 35.0 wt %) of repeat units of the comb copolymer viscosity modifier. Lubricant compositions comprising the comb copolymer viscosity modifier, as well as uses thereof and methods for modifying viscosity, are also contemplated herein.

A comb copolymer viscosity modifier may be made by polymerization comprising at least, or consisting essentially of, the following monomers: (a) a hydrogenated polybutadiene-based (alk)acrylate ester macromonomer (which repeat units may comprise from 7.0 wt % to 18 wt % of the repeat units of the comb copolymer viscosity modifier); (b) a C.sub.3-C.sub.8 alkyl (alk)acrylate ester monomer (which repeat units may comprise from 40 wt % to 71 wt % or from 45 wt % to 64 wt % of the repeat units of the comb copolymer viscosity modifier); and (c) a C.sub.12-C.sub.24 alkyl (alk)acrylate ester monomer, wherein repeat units based on the C.sub.12-C.sub.24 alkyl (alk)acrylate ester monomer comprise at least 21.0 wt % (and optionally up to 35.0 wt %) of repeat units of the comb copolymer viscosity modifier. Lubricant compositions comprising the comb copolymer viscosity modifier, as well as uses thereof and methods for modifying viscosity, are also contemplated herein.

A multi-grade lubricating oil including a (meth)acrylate polymer with at least two distinct molecular weight arms and a blend of heavier and lighter base oils with increased amounts of the heavier base oil to achieve SAE grade performance. The compositions herein achieve SAE certifications as lower CCS viscosities at target kinematic viscosities for multi-grade oils.

A multi-grade lubricating oil including a (meth)acrylate polymer with at least two distinct molecular weight arms and a blend of heavier and lighter base oils with increased amounts of the heavier base oil to achieve SAE grade performance. The compositions herein achieve SAE certifications as lower CCS viscosities at target kinematic viscosities for multi-grade oils.

This invention is directed to intramolecular crosslinked polymer chains, commonly known also as single-chain polymer nanoparticles (SCPNs), with high resistance to mechanochemical bond scission and to uses thereof in solution.

This invention is directed to intramolecular crosslinked polymer chains, commonly known also as single-chain polymer nanoparticles (SCPNs), with high resistance to mechanochemical bond scission and to uses thereof in solution.

Provided are a lubricating oil composition used in a diesel engine equipped with a forced-induction compressor, containing a base oil (A) containing a poly-α-olefin (A1), and a viscosity index improver (B) having an SSI (shear stability index) of 20 or less, having a distillation amount of a light fraction of 496° C. or less in a gas chromatography distillation test of less than 80% by volume, having a high retention of the effect of suppressing the formation of deposits that may occur inside the compressor, and being capable of retaining a high efficiency of the compressor for a long period of time, in the use thereof in a diesel engine equipped with a forced-induction compressor having an outlet temperature of the compressor becoming a high temperature reaching 190° C. or more, and a method for using the lubricating oil composition.

Provided are a lubricating oil composition used in a diesel engine equipped with a forced-induction compressor, containing a base oil (A) containing a poly-α-olefin (A1), and a viscosity index improver (B) having an SSI (shear stability index) of 20 or less, having a distillation amount of a light fraction of 496° C. or less in a gas chromatography distillation test of less than 80% by volume, having a high retention of the effect of suppressing the formation of deposits that may occur inside the compressor, and being capable of retaining a high efficiency of the compressor for a long period of time, in the use thereof in a diesel engine equipped with a forced-induction compressor having an outlet temperature of the compressor becoming a high temperature reaching 190° C. or more, and a method for using the lubricating oil composition.

A lubricating oil composition for an internal combustion engine has a HTHS viscosity at 150° C. of 2.55-2.84 mPa.Math.s and includes: (A) a lubricating base oil including (a) mineral base oil(s) and/or (a) synthetic base oil(s), and having a kinematic viscosity at 100° C. of 3.8-4.6 mm.sup.2/s; (B) 1000-2000 mass ppm, in terms of metal content, of a metallic detergent including (a) metal salicylate detergent(s), and delivering 10 mmol/kg of total salicylate soap base per kilogram of the composition; (C) 1.0 to 4.0 mass % of a comb-shaped poly(meth)acrylate having a Mw of 350,000-1,000,000 and a PDI of ≤4.0; and (D) 100-1000 mass ppm, in terms of nitrogen, of a succinimide dispersant including (i) (a) non-modified succinimide dispersant(s) and/or (ii) (a) boric acid-modified succinimide dispersant(s), wherein the (i) and the (ii), in total, deliver 70 mass % of total nitrogen content of the component (D).