A lubricant composition improves a performance of reducing a formation of compressor deposit. The lubricant composition also ensures low temperature properties of the lubricant composition. The lubricant composition includes 14 mass % or more of a fraction having a boiling point of 500 C. to 550 C. and 5 mass % or more of a fraction having a boiling point of over 550 C.

An object of the present invention is to provide a lubricating oil composition for hydraulic actuation which has excellent safety and which is imparted with electrical conductivity in order to prevent the generation of noise that adversely affects devices including hydraulic circuits equipped with an electronic control device for the valve system. The composition uses a hydrocarbon base oil, and the base oil contains from 30 to 250 ppm of ultrabasic magnesium salicylate in terms of magnesium content relative to the total amount of the composition, and from 0.07 to 5.0 mass % of non-dispersible polymethacrylate having a weight-average molecular weight of from 5,000 to 200,000 as a net amount relative to the total amount of the composition. The conductivity of the composition at 25 C. is 200 pS/m or more, the flash point is 240 C. or more, the pour point is negative 40 C. or less, and the coefficient of friction at 140 C. by a microclutch is 0.08 or more. This lubricating oil composition can be imparted with conductivity in order to prevent the generation of noise that adversely affects electronic controls when used in machinery equipped with electronic control devices.

Provided are marine lubricating oils including from 15 to 95 wt % of a Group III base stock having a kinematic viscosity at 100 deg. C. of 4 to 12 cSt, 0.5 to 55 wt % of cobase stock having a kinematic viscosity at 100 deg. C. of 29 to 1000 cSt, 0.1 to 2.0 wt % of a molydithiocarbamate friction modifier, 0.1 to 2.0 wt % of a zinc dithiocarbamate anti-wear additive, and 2 to 30 wt % of other lubricating oil additives. The cobase stock is selected from the group consisting of a Group I, a Group IV, a Group V and combinations thereof. Also provided are methods of making and using the marine lubricating oils.

A composition comprising an oil of lubricating viscosity and a compound represented by formula (I) wherein: R.sup.1 and R.sup.2 are each independently a hydrocarbyl group containing from about 4 to about 18 carbon atoms; p and q are each independently 0 or an integer from 1 to 3, and the sum of p and q is 1, 2, 3, 4, 5, or 6. The composition is effective at swelling seals.

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The invention provides a lubricating oil composition for automatic transmissions is made such that it comprises proportionately as its main constituents: 60 to 98 mass % as low viscosity base oils being base oils belonging to Groups 2 to 4 of the API (American Petroleum Institute) base oil categories wherein the kinematic viscosity at 100 C. is 2 to 5 mm.sup.2/s (Fischer-Tropsch synthetic oil comprising at least 45 to 80 mass %); 1 to 20 mass % as high-viscosity base oils being metallocene/poly--olefins with a kinematic viscosity at 100 C. of 100 to 600 mm.sup.2/s; and 1 to 20 mass % being a polymethacrylate with a weight-average molecular weight of 10,000 to 50,000. The viscosity index of this composition is not less than 190, the Brookfield viscosity at 40 C. is not more than 5000 mPa.Math.s, the 100 C. kinematic viscosity is 5 to 7 mm.sup.2/s, and the rate of reduction of the 100 C. kinematic viscosity after a KRL shear stability test (60 C., 20 hr) is not more than 3%.

The invention provides a lubricating oil composition being a lubricating oil composition containing a base oil composition which includes a lubricant base oil belonging to Group 3 of the base oil categories specified by the American Petroleum Institute (API) and a comb-like polymethacrylate-based viscosity index improver wherein the weight-halving temperature is not less than 310 C., and the sulphur content in the aforementioned lubricating oil composition is not more than 0.3 weight % in terms of the total weight of the aforementioned lubricating oil composition, and the aforementioned lubricating oil composition has an SAE viscosity grade of 0W-20, 5W-20 or 5W-30, a viscosity index of not less than 185 and a high-temperature high-shear viscosity at 100 C. of not more than 7.5 mPa.Math.s.

The invention is the use, as oil for aluminium and aluminium alloys cold rolling, of a fluid having a boiling point in the range of from 200 C. to 400 C. and a boiling range below 80 C., said fluid comprising more than 95% by weight isoparaffins and less than 3% by weight of naphthens, a biocarbon content of at least 95% by weight, containing less than 100 ppm by weight aromatics.

The invention is the use, in an electric vehicle, of a fluid having a boiling point in the range of from 200 C. to 400 C. and a boiling range below 80 C., said fluid comprising more than 95% by weight isoparaffins and less than 3% by weight of naphthens, a biocarbon content of at least 95% by weight, containing less than 100 ppm by weight aromatics.

Methods are provided for producing Group III base stocks having high viscosity and also having one or more properties indicative of a high quality base stock. The resulting Group III base stocks can have a viscosity at 100 C. and/or a viscosity at 40 C. that is greater than the corresponding viscosity for a conventional Group III base stock. Additionally, the resulting Group III base stocks can have one or more properties that are indicative of a high quality base stock.

Methods are provided for producing Group I base stocks having high viscosity and also having one or more properties indicative of a high quality base stock. The resulting Group I base stocks can have a viscosity at 100? C. and/or a viscosity at 40? C. that is greater than the corresponding viscosity for a conventional Group I bright stock formed by solvent processing. Additionally, the resulting Group I base stocks can have one or more properties that are indicative of a high quality base stock.