Disclosed is an effective thermal grease comprising a hyperbranched olefinic fluid and a thermally conductive filler. Property-modifying additives and fillers may also be included. The hyperbranched olefinic fluid is selected to have an average of at least 1.5 methine carbons per oligomer molecule and at least 40 methine carbons per one thousand total carbons. The thermal grease exhibits a flash point of 180° C. or higher, a pour point of 0° C. or lower, and a kinematic viscosity at 40° C. of no more than 200 cSt (0.0002 m 2/s). The composition may offer improved thermal conductivity, reduced tendency to migrate, and lower cost when compared with many other thermal greases, including silicone-based thermal greases.

Disclosed is an effective thermal grease comprising a hyperbranched olefinic fluid and a thermally conductive filler. Property-modifying additives and fillers may also be included. The hyperbranched olefinic fluid is selected to have an average of at least 1.5 methine carbons per oligomer molecule and at least 40 methine carbons per one thousand total carbons. The thermal grease exhibits a flash point of 180° C. or higher, a pour point of 0° C. or lower, and a kinematic viscosity at 40° C. of no more than 200 cSt (0.0002 m 2/s). The composition may offer improved thermal conductivity, reduced tendency to migrate, and lower cost when compared with many other thermal greases, including silicone-based thermal greases.

An object of the present invention is to provide a solid lubricant supplied to a surface of an image carrier of an electrophotographic image forming apparatus, wherein the solid lubricant comprises a fatty acid metal salt and polypropylene, and the polypropylene has an acid value of 1 mg KOH/g or more.

A lubricant composition of an oil of lubricating viscosity; an esterified copolymer with a backbone comprising units derived from (i) an α-olefin monomer of at least about 6 carbon atoms and (ii) an ethylenically unsaturated carboxylic acid in a mole ratio of 1:3 to 3:1; and a polymer comprising olefin monomer units of 3 to 5 carbon atoms, wherein at least 50 percent by weight of such units contain fewer than 6 carbon atoms and wherein less than 5 percent by weight of such units are ethylene monomer units; exhibits good power transfer efficiency and elastohydrodynamic film thickness.

[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.

[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 lubricating oil composition, and a method of reducing LSPI events employing the lubricating oil composition, including a base oil of lubricating viscosity, and an additive composition including: one or more overbased calcium-containing detergent(s) sufficient to provide at least 500 ppmw of calcium, and a zirconium-containing nanoparticle(s) and/or one or more zirconium-containing compound(s) sufficient to provide greater than 0 ppmw to 6000 ppmw of zirconium, wherein the nanoparticles have a size of from 1 to 500 nm, as measured by Dynamic Light Scattering, an amount of one or more molybdenum-containing compound present in an amount sufficient to provide no greater than 100 ppmw of molybdenum, and wherein the additive composition has a weight ratio of ppmw of zirconium provided by the zirconium-containing nanoparticle(s) and/or the one or more zirconium-containing compound(s) to the ppmw of calcium provided by the one or more overbased-calcium-containing detergent(s) of greater than about 0.01 to less than 5.

A lubricating oil composition, and a method of reducing LSPI events employing the lubricating oil composition, including a base oil of lubricating viscosity, and an additive composition including: one or more overbased calcium-containing detergent(s) sufficient to provide at least 500 ppmw of calcium, and a zirconium-containing nanoparticle(s) and/or one or more zirconium-containing compound(s) sufficient to provide greater than 0 ppmw to 6000 ppmw of zirconium, wherein the nanoparticles have a size of from 1 to 500 nm, as measured by Dynamic Light Scattering, an amount of one or more molybdenum-containing compound present in an amount sufficient to provide no greater than 100 ppmw of molybdenum, and wherein the additive composition has a weight ratio of ppmw of zirconium provided by the zirconium-containing nanoparticle(s) and/or the one or more zirconium-containing compound(s) to the ppmw of calcium provided by the one or more overbased-calcium-containing detergent(s) of greater than about 0.01 to less than 5.

A lubricating oil composition for industrial gears, including 10 to 90% by mass of a lubricant base oil (A) having a kinematic viscosity at 100° C. of 1 to 100 mm.sup.2/s, a viscosity index of 100 or more, and a pour point of 0° C. or lower, and 90 to 10% by mass of a liquid random copolymer (B) of ethylene and α-olefin, the liquid random copolymer (B) being prepared by means of a specific catalyst, wherein the total amount of (A) and (B) is 100% by mass, the lubricating oil composition for industrial gears having a kinematic viscosity at 40° C. of 100 to 10,000 mm.sup.2/s.

A lubricating oil composition for industrial gears, including 10 to 90% by mass of a lubricant base oil (A) having a kinematic viscosity at 100° C. of 1 to 100 mm.sup.2/s, a viscosity index of 100 or more, and a pour point of 0° C. or lower, and 90 to 10% by mass of a liquid random copolymer (B) of ethylene and α-olefin, the liquid random copolymer (B) being prepared by means of a specific catalyst, wherein the total amount of (A) and (B) is 100% by mass, the lubricating oil composition for industrial gears having a kinematic viscosity at 40° C. of 100 to 10,000 mm.sup.2/s.