A low-phosphorus lubricating composition having less than 600 ppm phosphorus, comprising at least 85 weight % of a lubricating base blend, and an additive comprising the following, as weight % of the total composition: (1) an organomolybdenum component comprising: (a) an organomolybdenum complex, and (b) a molybdenum dithiocarbamate, the organomolybdenum component being present at an amount which provides about 400-800 ppm Mo; (2) (iso-octyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate), at about 0.25-1.5%; (3) a dithiocarbamate component comprising (a) methylene-bis-dialkyldithiocarbamate and (b) said molybdenum dithiocarbamate, at a total dithiocarbamate component of about 0.6-1.2%; and (4) an alkylated diphenyl amine, at about 0.5-1.5%.

This invention provides a method for extending the life of a lubricant composition, said lubricant composition comprising one or more base oils and one or more additives, wherein at least one of the additive is a depleting additive, said method comprising: i. determining the amount of the one or more depleting additives required for a desired extended lifetime of the lubricant composition, wherein said extended lifetime is longer than the standard lifetime of said lubricant composition; ii. providing a first portion of said one or more depleting additives to the fresh lubricant composition; and iii. providing the remainder of the amount of the one or more depleting additives in two or more portions spread over the standard lifetime of the lubricant composition.

A low-phosphorus lubricating composition has less than 600 ppm phosphorus, comprising at least 85 weight % of a lubricating base blend, and an additive comprising the following, as weight % of the total composition: (1) an organomolybdenum compound at an amount which provides about 0.1-800 ppm Mo; (2) a hindered phenol at about 0.1-2%; and (3) a dithiocarbamate at about 0.1-2%; with a first proviso that where the dithiocarbamate does not comprise a metal dithiocarbamate, the additive additionally comprises: (4) an alkylated diphenylamine at about 0.1-2%, and with a second proviso that where the organomolybdenum compound comprises molybdenum dithiocarbamate, it is considered a metal dithiocarbamate for purposes of the first proviso, but is considered an organomolybdenum compound for the purposes of calculation of the amount present in the total composition.

The invention provides a lubricating composition containing an oil of lubricating viscosity and an ester, thioester, amide or imide of a carboxylic acid compound where said carboxylic acid is characterized in that it is functionalized with a hydroxy-substituted aromatic moiety. The invention further relates to methods of lubricating an internal combustion engine by supplying the described lubricating composition to the internal combustion engine. The invention further relates to the use of the salt of the carboxylic acid compound as an antiwear agent or an antioxidant.

Provided is a lubricating oil composition for an internal combustion engine containing: (A) a lubricant base oil with a kinematic viscosity at 100 C. of 2.0 mm.sup.2/s to 5.0 mm.sup.2/s; (B) 50 mass ppm to 2000 mass ppm of a molybdenum-based friction modifier based on the total amount of the composition as an amount of molybdenum; (C) a nitrogen-containing ashless friction modifier; (D) a succinimide or a derivative thereof as a dispersant; (E) an amine ashless antioxidant as an antioxidant; and (F) 1000 mass ppm to 2200 mass ppm of a metallic detergent based on the total amount of the composition as an amount of metal, wherein the amount of sulfated ash in the composition is 0.9 mass % or less, and a nitrogen management index is 0.60 or less. Provided is a lubricating oil composition for an internal combustion engine having improved fuel efficiency and oxidative stability, while maintaining low amount of sulfated ash.

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).

A lubricant composition comprises vegetable oil; nonionic surfactant; water in an amount of from about 0% to about 15% by weight based on total weight of the composition; optionally biocide; and optionally chelating agent, wherein the weight ratio of vegetable oil to nonionic surfactant is in a range of from about 1:1 to about 9:1. Also disclosed is a lubricant composition that comprises about 40% to about 90% by weight of vegetable oil; from about 10% to about 40% by weight of nonionic surfactant; from about 0% to about 15% by weight of based on total weight of the composition; optionally biocide; and optionally chelating agent. The disclosed lubricant compositions may further comprise the ester of fatty alcohol. Furthermore, a method of dry lubricating surface using the lubricant composition is disclosed.

The invention relates to an aqueous lubricant composition comprising at least: water; at least one polyalkylene glycol; at least one antifreeze compound selected from glycols, preferably alkylene glycols; glycerol; diglycerol; triglycerol, and mixtures thereof; at least one gallic acid ester; andat least one pH-regulating additive, making it possible to maintain the pH of said lubricant composition between (8) and (15). It also relates to the use of such an aqueous lubricant composition, for lubricating and/or cooling the moving parts in a mechanical system or as a hydraulic fluid. The invention also relates to the use of at least one gallic acid ester as an additive for improving the tribological properties of an aqueous lubricant composition.

The present invention relates to a composition a composition comprising compound of the general formula (I) ##STR00001## in which R.sup.1 a straight or branched C1-C24 alkyl group; R.sup.2 is a C1-C8 alkyl group; R.sup.3 is a C1-C8 alkyl group. The invention also relates to industrial products such as additive blends, engine oils and polymer compositions comprising this compound of the general formula (I) and to the use the compound of the general formula (I) as an additive such in industrial products such as additive blends, engine oils and polymer compositions.

A lubricant composition comprising an oil-soluble polyalkylene glycol; an ester compound selected from the group of natural esters and synthetic esters, and combinations thereof; and an additive mixture comprising an antioxidant and an anticorrosive, wherein the anticorrosive is selected from neutral alkali metal and alkaline earth metal salts of sulfonic acids, carboxylic acids, naphthoic acids, naphthenic acids, benzoic acids and phosphoric acids, and derivatives and combinations thereof.