[Problem]

From the points of view of improving the fuel efficiency of automobiles and industrial machines and saving energies thereof, the present invention provides lubricants having outstanding shear stability and low-temperature viscosity characteristics.

[Solution]

A lubricant composition includes a lubricant base oil (A) having a kinematic viscosity at 100° C. of 1 to 10 mm.sup.2/s, and an ethylene/α-olefin copolymer (B) in which (B1) the peak top molecular weight is 3,000 to 10,000, (B2) the copolymer shows no melting peak, (B3) the value B is not less than 1.1 and (B4) the kinematic viscosity at 100° C. is 140 to 500 mm.sup.2/s. The lubricant composition has a kinematic viscosity at 100° C. of not more than 20 mm.sup.2/s, a peak top of molecular weight in the range of 3,000 to 10,000, and a weight fraction of components having a molecular weight not less than 20,000 of 1 to 10% relative to all components having a molecular weight not less than the molecular weight that gives the peak top.

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 polyester is useful as a high viscosity base fluid. A method for its preparation involves isomerizing an alpha-olefin, epoxidizing an internal olefin, reacting an internal epoxide, and isolating the polyester. Lubricant compositions can contain such polyesters and the compositions are useful as automatic transmission fluids, manual transmission fluids, continuously variable transmission fluids, gear oil formulations, industrial gear oil formulations, axle fluid formulations, dual clutch transmission fluids, dedicated hybrid transmission fluids, or as hydraulic oils.

A polyester is useful as a high viscosity base fluid. A method for its preparation involves epoxidizing an alpha-olefin, reacting the alpha-epoxide or diol with a saturated linear aliphatic dicarboxylic acid, and isolating the polyester. Lubricant compositions can contain such polyesters and the compositions are useful as automatic transmission fluids, manual transmission fluids, continuously variable transmission fluids, gear oil formulations, industrial gear oil formulations, axle fluid formulations, dual clutch transmission fluids, dedicated hybrid transmission fluids, or as hydraulic oils.

A lubricant composition and method for improving engine performance using a renewable base oil composition comprising hydrocarbon mixtures and a lubricant additive having a sulfur content of up to about 0.4 wt. % and a sulphated ash content of up to about 0.5 wt. % is described herein.

The invention relates to random copolymers comprising monomers derived from conjugated dienes and alkyl (meth)acrylates, a method for manufacturing the copolymers, lubricant compositions comprising the copolymers, and the use of the copolymers as additives for lubricant compositions or as a base oil for lubricant compositions. The copolymers are favorably used for driving system lubricating oils, hydraulic oils, engine oils and industrial oil formulations.

The invention relates to a process for preparing random copolymers comprising monomers derived from conjugated diener and C.sub.7-C.sub.24 alkyl(meth)acrylates by free radical solution polymerization.

The present invention relates to hydrogenated linear copolymers comprising butadiene and isoprene monomer units, as well as the process for preparing these copolymers. The invention further relates to a lubricating oil composition comprising one or more hydrogenated linear copolymers according to the invention, as well as to the use of the aforementioned copolymers as a lubricant additive or a synthetic base fluid for lubricant compositions, especially in gear oils, transmission oils, hydraulic oils, engine oils, grease, marine oils or industrial lubricating oils.

Provided is an internal combustion engine lubricating oil composition having a major amount of an oil of lubricating viscosity; a combination of alkaline earth metal alkylhydroxybenzoate detergents; at least about 50 to about 500 ppm of boron from a boron containing detergent; a molybdenum containing compound in an amount to provide the lubricating oil composition from about 100 to about 1500 ppm molybdenum; a ZnDTP compound; where the composition comprises magnesium in an amount from about 100 to about 800 ppm, and calcium in an amount from about 500 to about 2000 ppm.

Provided is an internal combustion engine lubricating oil composition having a major amount of an oil of lubricating viscosity; a combination of alkaline earth metal alkylhydroxybenzoate detergents; at least about 50 to about 500 ppm of boron from a boron containing detergent; a molybdenum containing compound in an amount to provide the lubricating oil composition from about 100 to about 1500 ppm molybdenum; a ZnDTP compound; where the composition comprises magnesium in an amount from about 100 to about 800 ppm, and calcium in an amount from about 500 to about 2000 ppm.