This disclosure provides a process for producing vinylidene dimer derivatives by subjecting one or more vinylidene dimers and one or more carbonyl-containing compounds to a carbonyl-ene reaction, optionally in the presence of a catalyst, to produce one or more vinylidene dimer derived alcohols. This disclosure also provides a process for producing vinylidene dimer derivatives by reacting one or more vinylidene dimers with one or more carbonyl-containing compounds, optionally in the presence of a catalyst, to produce one or more vinylidene dimer derived alcohols. This disclosure further provides vinylidene dimer derivatives (e.g., vinylidene dimer derived alcohols and esters) produced by these processes. This disclosure still further provides for hydrogenating/reacting the vinylidene dimer derived alcohols with acids or anhydrides to produce vinylidene dimer derived esters. This disclosure yet further relates to lubricating ester oil base stocks, and lubricating oils containing the lubricating ester oil base stocks.

It is an object of the present invention to provide a grease composition, for an outer ring rotation type rolling bearing, which is capable of satisfying all of high-temperature durability, low-temperature property, peeling resistance, and rust-preventive property. A grease composition (7) to be enclosed in the outer rig rotation type rolling bearing for use in automotive electric auxiliary machines contains base oil, a thickener, a peeling-resistant additive, a wear-resistant additive, and a rust-preventive agent. The base oil is mixed oil of trimellitic acid ester oil and synthetic hydrocarbon oil mixed therewith in a mass ratio of (70:30) to (90:10). The thickener consists of a diurea compound shown by a formula (1).

R.sup.1NHCONHR.sup.2NHCONHR.sup.1(1)

wherein a reference symbol R.sup.2 denotes a divalent aromatic hydrocarbon group having a carbon number of 6 to 15, and a reference symbol R.sup.1 denotes a cyclohexyl group.

An oil composition comprising a first component having pendant groups, a second component having two or more terminal carbon chains, and optionally a third component, where a single molecule of the second component can form shearable stable structure with two molecules of the first component via van der Waals force between pendant groups and the terminal carbon chains. Shear stability of the oil can be improved if the total concentration of the heavy fraction of the shearable stable structure is controlled at a low concentration.

An oil composition comprising a first component having pendant groups and a second component but free of a third component and process for making such oil composition, where a single molecule of the third component can form large shearable stable complex structure with two molecules of the first component via van der Waals force between pendant groups and the terminal carbon chains, and a single molecule of the second component is capable of adjoining no more than one molecule of the first type. The oil composition has high shear stability making it suitable for use in lubricants subject to repeated high shear stress events.

The application provides a rolling bearing including a grease composition, the grease composition containing a base oil and a thickener, the base oil containing an aromatic ester-based base oil, and the thickener containing a urea-based thickener, where the grease composition has a storage elastic modulus at 25 C. of from 1200 to 3000 Pa as measured under conditions of a film thickness of 1 mm and a shear strain of 1% and has an oil separation amount at 80 C. of from 200 to 270 mm.sup.2/mg; a pivot assembly bearing apparatus including the rolling bearing; and a disk drive apparatus including the pivot assembly bearing apparatus.

Object

Objective is to provide a grease composition for a pivot assembly and a pivot assembly bearing filled with the grease composition, and to provide a bearing apparatus as well as a drive apparatus including the bearing apparatus, which is capable of suppressing adhesion of a volatilized component to a magnetic disk or the like even when the grease composition is volatilized by application of the grease composition and the bearing, thereby suppressing occurrence of read/write errors of an HDD.

Solution

Provided are: a grease composition for a pivot assembly bearing including an aromatic ester-based base oil and a thickener, the aromatic ester-based base oil containing an aromatic ester compound having an ester group *(CO)O as a substituent on a ring, where * is a bonding site to an aromatic ring, and having an alkyl group with a total of 8 or more carbon atoms bonded to an oxygen atom of the ester group; a pivot assembly bearing filled with the grease composition for pivot assembly bearing; a bearing apparatus including the pivot assembly bearing; and a disk drive apparatus equipped with the bearing apparatus.

A method for reducing the friction coefficient of a lubricating oil composition in the lubrication of a mechanical device comprises formulating said lubricating oil composition with a carboxylic acid ester obtainable by reacting a mixture comprising at least on dicarboxylic acid and at least one branched C.sub.10 alcohol.

The present invention provides a lubricant composition which can be used as a lubricant for a rolling component, the composition capable of maintaining enhanced lubrication performance over a long period of time even under high temperature conditions such as temperatures of 180 C. or higher, and a rolling bearing including the lubricant composition sealed therein. A lubricant composition-sealed bearing 1 includes a lubricant composition 7 that is sealed in the peripheries of the rolling bodies 4. The lubricant composition 7 contains a base oil and an antioxidant. The base oil is an oil mixture of an alkyl diphenyl ether oil and at least one oil selected from a poly--olefin oil and an ester oil, and contains the alkyl diphenyl ether oil in an amount of 50% or more by weight of the total base oil. The antioxidant is 2,2,4-trimethyl-1,2-dihydroquinoline or a polymer thereof, and is contained in an amount of 0.1% to 10% by weight of the total lubricant composition.

A grease composition according to an embodiment includes a base oil, a thickener and 0.5% by weight or more of a dispersing agent, the dispersing agent including at least one of a carboxylic acid metal salt, a metal salt of a polycarboxylic acid and a copolymer of a carboxylic acid metal salt and a hydrocarbon compound.

A threaded tubular component configured for drilling or working hydrocarbon wells, the tubular component including, at one of its ends, a threaded zone formed on its external or internal peripheral surface depending on whether the threaded end is male or female in type. The end portion is at least partially coated with a dry film, including a thermoplastic or thermoset matrix including microcapsules filled with compounds in liquid form.