A dispersant for a lubricating oil, containing at least one compound selected from a specific nitrogen-containing compound which is obtained by using, as raw materials, (A) at least one polyolefin selected from polybutene and polyisobutene, (B) at least one maleic acid compound selected from maleic acid and maleic anhydride, and (C) polyamine; a boride of the specific nitrogen-containing compound; and an acylated product of the specific nitrogen-containing compound. The polyolefin (A) satisfies at least one of the following conditions () and (). () a ratio (Sb/Sa) of an integrated value (Sb) of a peak present at 4.40 to 5.00 ppm in a .sup.1H-NMR spectrum to an integrated value (Sa) of a peak present at 5.01 to 5.60 ppm in the 1H-NMR spectrum is 2 or more. () a ratio (Sd/Sc) of an integrated value (Sd) of a peak present at 1.76 to 2.10 ppm in the 1H-NMR spectrum to an integrated value (Sc) of a peak present at 1.65 to 1.75 ppm in the .sup.1H-NMR spectrum is 1 or more.

The invention provides a grease composition used for lubricating a mechanical part having a steel portion to be lubricated which performs a rolling motion and a rolling and sliding motion, containing a base oil, a thickener and an additive, wherein the additive includes at least one compound selected from the group consisting of polyethylene wax, oxidized polyethylene wax, polypropylene wax, montan wax and amide wax.

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

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

A polyisobutylene-substituted hydroxyaromatic compound and derivatives thereof which are suitable for use as additives in lubricating compositions. The polyisobutylene-substituted hydroxyaromatic compound may include the reaction product of a hydroxyaromatic compound with a polyisobutylene having a number average molecular weight of 150 to 800.

A polyisobutylene-substituted hydroxyaromatic compound and derivatives thereof which are suitable for use as additives in lubricating compositions. The polyisobutylene-substituted hydroxyaromatic compound may include the reaction product of a hydroxyaromatic compound with a polyisobutylene having a number average molecular weight of 150 to 800.

The disclosed technology provides a lubricating composition comprising an oil of lubricating viscosity and a detergent comprising a polyolefin-substituted hydroxy-aromatic carboxylic acid or salt thereof, wherein the polyolefin is derived from a branched alkene having at least 4 carbon atoms and wherein the polyolefin has a number average molecular weight of 150 to 800. The invention further relates to a method of lubricating a mechanical device with the lubricant composition.

The disclosed technology provides a lubricating composition comprising an oil of lubricating viscosity and a detergent comprising a polyolefin-substituted hydroxy-aromatic carboxylic acid or salt thereof, wherein the polyolefin is derived from a branched alkene having at least 4 carbon atoms and wherein the polyolefin has a number average molecular weight of 150 to 800. The invention further relates to a method of lubricating a mechanical device with the lubricant composition.

Ethylene-C.sub.3-C.sub.10 alpha olefin copolymers, dispersants and lubricating oils/fuel compositions incorporating dispersants, and related methods are generally described herein. The copolymer may comprise ethylene-derived units and C.sub.3-C.sub.10 alpha-olefin-derived units. The C.sub.3-C.sub.10 alpha-olefin-derived units may have a carbon number from three to ten. For example, the C.sub.3-C.sub.10 alpha-olefin-derived units may be propylene-derived units.

The present application describes a new process for the preparation of polyisobutene derivatives, such polyisobutene derivatives, and their use. The process irradiates a reaction mixture containing an oxygen-containing gas in contact with polyisobutene, a photosensitizer and an optional solvent, with monochromatic light emitted from an electroluminescent lighting device, at least 90% of power of said monochromatic light and at most 100% of said power being emitted in the range from 350 nm to 680 nm.