Disclosed is a method of treating a used hydrocarbon lubricant of ISO Viscosity Grade 46 or higher comprising oxidation products that adversely affect lubricant performance. The hydrocarbon lubricant has a Group II hydrocarbon oil or Group III hydrocarbon oil, optionally one or more lubricant additives, and an amount of varnish. The hydrocarbon lubricant is free of zinc-containing additives. The method comprises adding to the used hydrocarbon lubricant from about 2 percent by weight to about 20 percent by weight of a polyhydroxy polypropylene oxide homopolymer that has a hydroxyl number of from about 12 mg KOH/g to about 58 mg KOH/g as measured according to ASTM D4274.

Provided is a mineral base oil having a kinematic viscosity at 40 C. of 4.0 mm.sup.2/s or more and less than 6.0 mm.sup.2/s, a kinematic viscosity at 100 C. of 1.0 mm.sup.2/s or more and less than 2.0 mm.sup.2/s, and a flash point of 140 C. or higher. A lubricating oil composition containing the mineral base oil has a high flash point while having a low viscosity and thus having excellent fuel-saving performance when used as a driving system oil and the like.

The presently claimed invention is directed to poly(meth)acrylate copolymers containing alkyl(meth)acrylate comonomer with branched C17 alkyl group. The invention is further related to lubricating oil compositions comprising poly(meth)acrylate copolymers containing alkyl(meth) acrylate comonomer with branched C17 alkyl group as viscosity index improving component.

The invention provides a method for improving the air release of a lubricating oil as measured by ASTM D3427. The method comprises a step of mixing an additive into the lubricating oil.

The present invention relates to novel aminobisphosphonate compounds useful as antiwear and/or friction modifier additive components, lubricant additive compositions and lubricant compositions each comprising such compounds, and methods for making and using the same.

A fluorescent solution is disclosed for use in a hydraulic or diesel fluid to facilitate detection of injection of the hydraulic of diesel fluid into a human. The fluorescent solution includes a fluorescent dye and a stabilizing agent. The stabilizing agent may be a surfactant. A hydraulic fluid mixture is also disclosed which includes a fluorescent solution and a hydraulic fluid.

Provided are a lubricant composition for shock absorbers, a lubricant additive, and a method of adjusting friction characteristics of a lubricant composition for shock absorbers, each capable of satisfying both the operational stability and ride comfort. The lubricant composition for shock absorbers contains a base oil and a friction adjusting agent, the friction adjusting agent contains pentaerythritol esters, and the pentaerythritol esters contain a pentaerythritol tetraester and a pentaerythritol ester other than the pentaerythritol tetraester.

An oil-soluble phosphorus antiwear additive and a lubricating composition including the ashless antiwear additive having improved copper corrosion performance obtained by reacting an organic hydroxy compound with phosphorus pentasulfide to form a reaction product, distilling the reaction product and recovering a condensate, and reacting the condensate with an unsaturated ester of a carboxylic acid to form an oil-soluble phosphorus antiwear additive.

The presently claimed invention is directed to novel polyesters which are obtainable by reacting a mixture comprising at least one C8-C20 Guerbet alcohol, at least one aliphatic or cycloaliphatic dicarboxylic acid and at least one polyol with a hydroxyl functionality in the range of ?2 to ?6 and the use of these polyesters as a component of lubricating oil compositions.

The present invention provides a water-soluble lubricating oil including a water-soluble base (A) and a corrosion inhibitor (B). The water-soluble base (A) contains at least one polyether (A1). A 0.1% by weight aqueous solution of the water-soluble lubricating oil has a surface tension of 31 mN/m or higher.