A lubricating grease composition includes a base oil, a thickener, and a solid lubricant, wherein the base oil is a synthetic hydrocarbon oil with a kinematic viscosity of 600 to 2000 mm.sup.2/s at 40 C., the thickener is a barium complex soap, and the solid lubricant is an inorganic fine particle with Mohs hardness of 3 to 6 and an average particle size of 10 to 40 m.

This invention relates to unsaturated polyol esters that can be used in hydraulic fluid applications, including fire-resistant hydraulic fluid applications, marine hydraulic fluid applications, metalworking fluid applications, food grade fluid applications, and transformer fluid applications, and methods for making the same.

A lubricating oil composition for industrial machines containing a base oil (A) and a specific acylglycerol (B) and having excellent brake squeal preventing performance, and a lubrication method using the composition.

An industrial fluid is disclosed. The fluid comprises an oleaginous component, an aqueous component, and a surfactant dispersed in the aqueous component. The industrial fluid does not contain defoamers or anti-foam compounds. The surfactant is bound within micelles of the oleaginous component and the aqueous component.

A lubricating oil composition prepared by blending a base oil (A) containing a compound (A1) that is an ester or ether and has two or more aromatic rings, with a polyalkylene glycol (B) is provided. The lubricating oil composition has a high density (i.e., a high bulk modulus), a high viscosity index, and excellent shear stability.

A viscosity index improver comprising a copolymer having a unit (a) derived from a maleimide monomer and a unit (b) derived from a macromonomer, wherein viscosity measured by the following method is 8000 mPa.Math.s or less. Viscosity measurement method: A solution composed of 78 mass % of a Group III base oil (viscosity index: 122, kinematic viscosity at 40 C.: 19.6 mm.sup.2/s) on the American Petroleum Institute (API) classification and 22 mass % of the copolymer is measured with a viscometer (TVB-10 manufactured by Toki Sangyo Co., Ltd., rotor: SPINDLE No. M3, rotation speed: 6 rpm) at 25 C.

Polyalkyl(meth)acrylate (PAMA) polymers comprising a certain amount of hydroxyl-functionalized alkyl (meth)acrylates can be used for improving the demulsibility performance of high VI lubricating oil compositions. The lubricating oil compositions can be those which are based on apolar base oils, especially hydraulic fluid compositions. The polymers can be comprised in certain lubricating oil compositions.

A method for improving wear control and sludge control, while maintaining or improving fuel efficiency, of a lubricating oil in an engine or other mechanical component lubricated with the lubricating oil by using as the lubricating oil a formulated oil. The formulated oil has a composition including a lubricating oil base stock as a major component, and at least one lubricating oil additive, as a minor component. The at least one lubricating oil additive includes a zirconium-containing compound. The zirconium-containing compound is present in an amount from about 0.1 to about 1200 parts per million (ppm). The zirconium-containing compound is soluble in the lubricating oil base stock. The lubricating oil is useful as a passenger vehicle engine oil (PVEO), a commercial vehicle engine oil (CVEO), and other lubricating oils (hydraulic, gear, transmission, etc.).

A lubricating composition includes an oil of lubricating viscosity and an ionic tetrahedral borate compound which includes a cation and a tetrahedral borate anion which includes a boron atom, the boron atom having at least one aromatic bidentate di-oxo ligand. The compound may be represented by formula (I), where R.sup.1 and R.sup.2 are selected from C.sub.1-48 hydrocarbyl groups or together form a substituted or unsubstituted 5- or 6-membered ring; R.sup.3 and R.sup.4 together represent a substituted or unsubstituted aromatic ring; m is 0 or 1; X is hydrogen, a C.sub.1-24 hydrocarbyl group, OR.sup.5, NHR.sup.5, or ?O, R.sup.5 is a C.sub.1-24 hydrocarbyl group; M represents the cation; and n is at least 1. The cation may be selected to provide detergent and/or dispersant properties to the lubricating composition. In the case of ammonium cations, the molecular weight may be 260 g/mol or higher for providing a highly soluble compound, particularly when X is ?O. ##STR00001##

Sustainable lubricant compositions made from recycled thermoplastic polyesters and other reclaimed or biorenewable reactants and a method of formulating them are disclosed. The lubricant compositions comprise a polyester base oil, which incorporates recurring units from a digested thermoplastic polyester, a low-molecular-weight polyol, and C.sub.8-C.sub.24 fatty acid. The base oil has a number-average molecular weight within the range of 300 to 5000 g/mol, a hydroxyl value less than 50 mg KOH/g, and a viscosity at 40 C. less than 5000 cSt. Some of the lubricant compositions comprise the polyester base oil and one or more additives including anti-wear agents, corrosion inhibitors, antioxidants, thickeners, detergents, and the like. The lubricants have properties that rival those of commercial products made from nonrenewable hydrocarbon blends or polyol esters and are useful for many practical applications such as internal combustion engine oils, gear lubrication oils, hydraulic oils, compressor oils, metal working fluids, and lubricating greases.