A composition including one or more diester compounds represented by the formula as defined herein. The composition has a viscosity (Kv.sub.100) from about 1 cSt to about 10 cSt at 100 C. as determined by ASTM D445, a viscosity index (VI) from about 100 to about 300 as determined by ASTM D2270, and a Noack volatility of no greater than 50 percent as determined by ASTM D5800. A process for producing the composition, a lubricating oil base stock and lubricating oil containing the composition, and a method for improving one or more of thermal and oxidative stability, solubility and dispersancy of polar additives, deposit control and traction control in a lubricating oil by using as the lubricating oil a formulated oil containing the composition.

A volatile methyl siloxane lubricant for use in the process of laminating lithium sheets into lithium films is disclosed.

A lubricating composition comprises an amide and at least one additive. The amide is the reaction product of a secondary, branched amine and a carboxylic acid. The carboxylic acid may be a monocarboxylic acid or a dicarboxylic acid, including dimer acid. The amide is hydrolytically stable, and may be used to increase the hydrolytic stability of the lubricant composition. Alternatively, the amide may be used to increase the additive solubility or detergency of the lubricant composition.

A lubricating oil composition that is hard to increase in viscosity in the low temperature range and is easy to increase in viscosity in the high temperature range. The lubricating oil composition contains a base oil and a viscosity index improver. The base oil contains a mineral oil and an oxygen-containing synthetic oil. The viscosity index improver contains a comb-shaped polymer. The lubricating oil composition has a kinematic viscosity of 100 C. of 9.3 mm.sup.2/s or less, a viscosity index of 280 or more, and a content Y (% by mass) of the oxygen-containing synthetic oil based on the total amount of the lubricating oil composition satisfying the following expression (1): Y<3.7 ln(X)+ (1), where =0.5, =19, and X represents a ratio of the number of carbon atoms and the number of oxygen atoms per one molecule of the oxygen-containing synthetic oil.

Object

To provide a fluid dynamic pressure bearing oil and a fluid dynamic pressure bearing filled with the fluid dynamic pressure bearing oil, and to provide a spindle motor and a disk drive device including the spindle motor in which the fluid dynamic pressure bearing oil and the bearing are used, thereby suppressing adhesion of a volatile component to a magnetic disk or the like even when the fluid dynamic pressure bearing oil is volatilized, so that occurrence of HDD read/write errors can be suppressed.

Solution

A fluid dynamic pressure bearing oil contains at least one compound selected from the group consisting of a monoester compound represented by the following Formula (1) and a diester compound represented by the following Formula (2): R.sub.1C(O)OR.sub.2 (1) (where R.sub.1 is an alkyl group having 10 or more carbon atoms in total, R.sub.2 is an alkyl group having 9 or more carbon atoms in total, and R.sub.3-E.sub.1-R.sub.4-E.sub.2-R.sub.5 (2) (where R.sub.3 and R.sub.5 are each independently an alkyl group having 8 or more carbon atoms in total, R.sub.4 is an alkylene group having 4 or more carbon atoms in total, and E.sub.1 and E.sub.2 are each independently C(O)O or OC(O).