A hydraulic fluid includes an oil of lubricating viscosity and at least 2 wt. % of an ester of a carboxy group-containing interpolymer comprising units derived from a vinyl aromatic monomer and units derived from a carboxylic acid monomer. The interpolymer also contains nitrogen functionality. The hydraulic fluid is at least substantially free of polyacrylates and polymethacrylates.

A lubricating composition suited to use for lubricating a hydraulic system includes an oil of lubricating viscosity and a compound comprising a polyolefin-substituted bridged hydroxyaromatic compound or metal salt thereof, wherein the wherein the polyolefin is derived from a isobutylene having a number average molecular weight of 150 to 800.

The invention provides a lubricating oil composition comprising a ethylene/-olefin copolymer and, optionally, and additive comprising an amine salt of a hydrocarbyl thiophosphoric acid ester. The invention also provides a method of improving air release of a lubricating oil composition by mixing an ethylene/-olefin copolymer with an oil of lubricating viscosity.

A lubricating oil composition including 100 mass parts of (A) an ester compound, 0.05 to 1.5 mass parts of (B) an amine salt of an acidic phosphoric ester and 0.01 to 0.50 mass parts of (C) a monoesterified compound, wherein (A) the ester compound is an ester compound of trimethylolpropane, a straight-chain saturated fatty acid having a carbon number of 8 to 10 and adipic acid; (B) the amine salt is an amine salt of an acidic phophoric ester; and (C) the monoesterified compound is a monoesterified compound of an alkane diol having a carbon number of 3 to 8 and of succinic acid having an alkyl group having a carbon number of 8 to 18 or an alkenyl group having a carbon number of 8 to 18.

The invention relates to low molecular weight hydrogenated polybutadienes and to a method for the preparation of these polymers. The invention is also directed to lubricant compositions comprising these polymers and uses thereof.

A fully-formulating lubricating composition comprising an oil of lubricating viscosity; an ionic tetrahedral borate compound including a tetrahedral borate anion having a boron atom with two bidentate di-oxo ligands both being a linear C18-tartrimide; a first dispersant comprising a conventional ammonium substituted polyisobutenyl succinimide compound having a polyisobutenyl number average molecular weight of 750 to 2,500; a second dispersant comprising an ammonium substituted polyisobutenyl succinimde compound having an N:CO ratio of 1.8 and a polyisobutylenyl number average molecular weight of 750 to 2,500, wherein one or more of the first dispersant and the second dispersant are in cationic form. The fully formulated lubricating composition including one or more performance additives.

Disclosed are Group III base stocks comprising greater than or equal to about 90 wt. % saturated hydrocarbons (saturates); a viscosity index from 120 to 145; a unique ratio of molecules with multi-ring naphthenes to single ring naphthenes (2R+N/1RN); a unique ratio of branched carbons to straight chain carbons (BC/SC); a unique ratio of branched carbons to terminal carbons (BC/TC); and unique MRV behavior as a function of base stock naphthene ratio (2R+N/1RN). A method for preparing the base stocks is also disclosed. Also disclosed is a lubricating oil having the base stock as a major component, and an additive as a minor component.

A hydrocarbon fluid is disclosed that has a pour point of at most 30 C., as measured by ASTM D5950, and that comprises at least 99 wt % of naphthenes and paraffins, based on the total weight of the hydrocarbon fluid, wherein the weight ratio of naphthenes to paraffins is at least 1, as measured by GC-MS, and wherein the paraffins consist essentially of isoparaffins, as determined by GC-FID. In addition, preferred uses of said hydrocarbon fluid are disclosed.

The present invention relates to a lubricant composition, and more particularly to a lubricant composition, which has superior oxidation stability and friction characteristics even under harsh conditions of high temperature and high pressure and is thus suitable for use in hydraulic oil. The lubricant composition of the present invention includes a base oil, a liquid olefin copolymer, a phosphorothioate compound, and phosphonium phosphate.

An antioxidant package composition including a combination of: (i) at least one aromatic amine, and (ii) at least one polyether sulphide; a lubricant composition including: (a) the above antioxidant package and (b) at least one base oil; a process for preparing the antioxidant package; and a process for preparing the lubricant composition.