This disclosure relates to a lubricating oil (e.g., gear oil) for use in an electric or hybrid vehicle. The lubricating oil has a composition including one or more lubricating oil base stocks as a major component, and one or more lubricating oil additives, as a minor component. The one or more lubricating oil base stocks include at least one Group IV base oil, or at least one Group V base oil. The lubricating oil has a kinematic viscosity (KV.sub.100) from 1 cSt to 7 cSt at 100° C. as determined by ASTM D-445, and an electrical conductivity at room temperature of less than 15,000 pS/m as determined by ASTM D-2624. This disclosure also relates to methods for producing a lubricating oil for a transmission, gear train, gear set, gear box, or gears of an electric vehicle powertrain and methods for improving energy efficiency, while maintaining or improving wear control.

A hydrocarbon fluid is disclosed that has a pour point of at most −30° C., as measured by ASTM D5950, and that comprises at least 99 wt % of naphthenes and paraffins, based on the total weight of the hydrocarbon fluid, wherein the weight ratio of naphthenes to paraffins is at least 1, as measured by GC-MS, and wherein the paraffins consist essentially of isoparaffins, as determined by GC-FID. In addition, preferred uses of said hydrocarbon fluid are disclosed.

Hydrophilic coatings including a base coat layer and a top coat layer wherein at least one of the base coat and top coat compositions that form the hydrophilic coatings comprises a diacrylate compound have a number average molecular weight less than 1000.

A working fluid composition for a refrigerating machine, containing: a refrigerant containing trifluoroiodometbane; and a refrigerating machine oil containing a polyol ester and a hindered phenol compound, wherein a content of the hindered phenol compound is 0.6 to 10% by mass based on a total amount of the refrigerating machine oil.

A lubricating oil composition including a base oil (X) having a tertiary carbon atom at a content of 8.0 at % or more based on the total carbon of hydrocarbons and an antioxidant (Y) having an amine-based antioxidant (A), a phenol-based antioxidant (B), and a phosphor-based antioxidant (C). The amine-based antioxidant (A) includes a diphenylamine compound (A1) represented by the following general formula (a1):

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where R.sup.a1 and R.sup.a2, na1 and na2 are defined in the disclosure.

A lubricating oil composition may be capable of satisfactorily exhibiting sludge prevention properties and wear resistance evaluated by scoring resistance and seizure resistance over a long period of time. Such a lubricating oil composition may contain: a base oil (A); a hindered phenol-based antioxidant (B); one or more imide compounds (C) selected from the group consisting of a monoimide compound (C1) and a bisimide compound (C2); and an extreme pressure agent (D), in which the hindered phenol-based antioxidant (B) is 2,6-di-tert-butylphenol, the monoimide compound (C1) is one or more selected from the group consisting of an alkenyl succinic monoimide compound and an alkyl succinic monoimide compound, and the bisimide compound (C2) is one or more selected from the group consisting of an alkenyl succinic bisimide compound and an alkyl succinic bisimide compound.

A lubricating oil composition for an internal combustion engine includes: a lubricant base oil including at least one mineral base oil, at least one synthetic base oil, or any combination thereof, and having a kinematic viscosity at 100° C. of 3.0 to 4.0 mm.sup.2/s and a NOACK evaporation loss at 250° C. of no more than 15 mass %; (A) a calcium-containing metallic detergent in an amount of no less than 1000 mass ppm and less than 2000 mass ppm in terms of calcium; (B) a magnesium-containing metallic detergent in an amount of 100 to 1000 mass ppm in terms of magnesium; (G) a zinc dialkyl dithiophosphate in an amount of no less than 600 mass ppm in terms of phosphorus; and optionally (C) a viscosity index improver in an amount of no more than 5 mass %.

An aspect of the present invention provides a refrigerating machine oil containing an ester-based base oil, at least one epoxy compound selected from an alkyl glycidyl ether and an aryl glycidyl ether, and a phenol-based antioxidant, wherein a content of the epoxy compound is 0.7% by mass or more based on a total amount of the refrigerating machine oil, and the refrigerating machine oil is used with a refrigerant containing trifluoroiodomethane.

A method for inhibiting adsorption of α-olefin in a lubricant composition to a metal surface is disclosed. The lubricant composition comprises any of oils of Group III, Group IV and polyisobutylenes classified into Group V according to the API base oil classification or a mixture thereof as a base oil, and the α-olefin coexisting in an amount of 1% by mass or less based on the total amount of the composition. The method comprises adding a sarcosinic acid derivative, an aspartic acid derivative or a diethanolamine derivative, or a mixture thereof to the lubricant composition.

A lubricant composition comprising a base oil; at least one additive; and 0.001-10% by weight, based on the total weight of the lubricant composition, of an organic compound comprising both a polar moiety and a nonpolar moiety, as lubricity improver, wherein the organic compound has a relative permittivity ε.sub.r in the range from 1.5 to 10, and a quotient ∫S.sub.1/∫S.sub.2 for the organic compound is in the range from 1 to 25, wherein ∫S.sub.1 denotes the sum total of the area(s) of the IR absorption band(s) in the wavenumber range of 3100-2750 cm.sup.−1 in an ATR spectrum of the organic compound, and ∫S.sub.2 denotes the sum total of the area(s) of the IR absorption band(s) in the wavenumber range of 1800-1650 cm.sup.−1 in an ATR spectrum of the organic compound.