The present invention relates to copolymers, to a method for the preparation of these copolymers, to the use of these copolymers for reducing wear in a lubricant composition, to lubricant compositions comprising these copolymers, and to the use of these lubricant compositions as an automatic transmission fluid, a continuously variable transmission fluid, an engine oil, a gear oil, or a hydraulic oil.

A lubricating oil composition for hydraulic oils including 10 to 99% by mass of a lubricant base oil (A) with a kinematic viscosity at 100° C. of 1 to 14 mm.sup.2/s, a viscosity index of 100 or more, and a pour point of 0° C. or lower, and 90 to 1% by mass of a liquid random copolymer (B) of ethylene and α-olefin prepared using a specific catalyst, wherein the total amount of (A) and (B) is 100% by mass, and having a kinematic viscosity at 100° C. of 10 to 300 mm.sup.2/s.

Provided is a lubricating oil composition comprising a base oil (A) containing a polyalkylene glycol (A1) and a polyol ester (A2), a phosphorus-based rust inhibitor (B), and an antioxidant (C) containing an amine-based antioxidant (C1). The lubricating oil composition exhibits a strong effect for suppressing sludge sedimentation even when used for an extended period of time in a high-temperature environment, and has excellent demulsibility and rust preventive properties, and therefore, can be suitably used in turbomachinery, compressors, hydraulic equipment, and machine tools.

Provided is a mixed powder for powder metallurgy that contains a readily available compound as a lubricant, does not need to contain a stain-causing metal soap, has excellent ejection properties and compressibility, and can exhibit excellent fluidity without deteriorating the ejection properties or the compressibility even in the case of further containing carbon black. The mixed powder for powder metallurgy comprising an (a) iron-based powder and a (b) lubricant, wherein the (b) lubricant is an ester of disaccharide and fatty acid represented by R—COOH, and the R is an alkyl group having 11 or more carbon atoms or an alkenyl group having 11 or more carbon atoms.

The invention is related to a composition for use in hydraulic systems of an aircraft. The composition typically comprises an adipic acid-based polyester in a phosphate ester base stock substantially consisting of trialkyl phosphates.

A liquid blend of octylated phenyl-α-naphthylamine, and at least one low molecular weight aromatic ester, wherein the octylated phenyl-α-naphthylamine is present from about 15% to about 35% by weight of the blend, as well as a lubricating composition comprising a lubricant base and an amount of the blend which provides up to 2.0% by weight of the octylated phenyl-α-naphthylamine in the composition.

A lubricant additive includes a monoester carboxylic acid salt (A) represented by formula (1). ##STR00001## In formula (1), R.sup.1 represents a single bond between carbon atoms of carbonyl groups, or a divalent hydrocarbon group having 1 to 4 carbon atoms, and R.sup.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.

A lubricant additive includes a monoester carboxylic acid salt (A) represented by formula (1).

##STR00001##

In formula (1), R.sup.1 represents a single bond between carbon atoms of carbonyl groups, or a divalent hydrocarbon group having 1 to 4 carbon atoms, and R.sup.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.

The present disclosure relates to an anti-wear, anti-friction and stably-dispersed lubricating oil or grease, and the anti-wear, anti-friction and stably-dispersed lubricating oil or grease includes a main component of a lubricating oil or grease and a long carbon chain-grafted sulfonated graphene, the preparation method of which includes mixing a main component of a lubricating oil or grease with a long carbon chain-grafted sulfonated graphene, stirring and dispersing the mixture to obtain the product. The lubricating oil or grease in the present disclosure can significantly improve the long-term dispersion stability and dispersion stability in a complex environment by adding a long carbon chain-grafted sulfonated graphene in the main component, and at the same time can significantly improve the friction coefficient, which can significantly improve the anti-wear and anti-friction properties of the lubricating oil or grease, reduce the diameter of wear scars, and reduce the wear of copper and iron.

There is disclosed an antifoam component for a mechanical device which includes a poly(acrylate) copolymer. The antifoam component has improved foam performance in finished fluids utilizing dibutyl hydrogen phosphite compounds, such as driveline fluids. A lubricating composition comprising a) at least one oil of lubricating viscosity; and b) an antifoam component comprising a poly(acrylate) copolymer. The poly(acrylate) copolymer, b) may include (i) from about 30 wt % up to about 99 wt % of a (meth)acrylate monomer having C.sub.1 to C.sub.4 alkyl esters of (meth)acrylic acid; and (ii) from about 1 wt % up to about 70 wt % of a fluorinated (meth)acrylate monomer.