Abstract: The present invention provides a poly(meth)acrylate-based viscosity index improver comprising a polymer chain comprising a structural unit represented by the following formula (1) and a structural unit represented by the following formula (2), wherein Mw is 100000 or more, and Mw/Mn, is 1.6 or less. [R1 represents hydrogen or a methyl group, and R2 represents a group represented by the following formula (3), and R3 represents a C1 to C18 alkyl group that is straight-chain or has a branch having 5 or less carbon atoms. m and n are integers which satisfy m?5, n?4, and m+n?31.

Abstract: A lubricant base oil that is a hydrocarbon oil that satisfies any of the following conditions (i), (ii) and (iii): (i) a hydrocarbon oil having a kinematic viscosity at 100° C. of 3.0 to 5.0 mm2/s, a viscosity index of 145 or more, and an SBV viscosity at ?20° C. of 3,000 to 60,000 mPa·s, (ii) a hydrocarbon oil having a kinematic viscosity at 100° C. of 5 to 9 mm2/s, a viscosity index of 155 or more, and an SBV viscosity at ?20° C. of 3,000 to 30,000 mPa·s, and (iii) a hydrocarbon oil having a kinematic viscosity at 100° C. of 2.0 to 3.0 mm2/s, a viscosity index of 130 or more, and an SBV viscosity at ?30° C. of 1,000 to 30,000 mPa·s.

Abstract: A lubricant base oil that is a hydrocarbon oil having a kinematic viscosity at 100° C. of 2.0 to 9 mm2/s, a viscosity index of 130 or more, a freezing point of ?30 to ?5° C., and an SBV viscosity at ?20° C. of 1,000 to 60,000 mPa·s, in which the freezing point of the lubricant base oil is higher by 10° C. or more than a freezing point of raffinate obtained by bringing the lubricant base oil into contact with urea and removing paraffin that can be included in the urea.

Abstract: The present invention provides a succinimide compound represented by the following formula (1-1) or (1-2), and a lubricating oil additive and a lubricating oil composition which contain the succinimide compound. wherein R represents an alkyl group or an alkenyl group having a number-average molecular weight of 500 or greater and less than 5000. wherein R represents an alkyl group or an alkenyl group having a number-average molecular weight of 500 or greater and less than 5000.

Abstract: The first refrigerating machine oil composition of the invention comprises a predetermined base oil, and at least one ester additive selected from esters of a monobasic fatty acid having 12 or more carbon atoms and a monohydric alcohol having 1-24 carbon atoms, and an ester of a chain-like dibasic acid and a monohydric alcohol. The second refrigerating machine oil composition of the invention comprises a predetermined base oil, and at least one oxygen-containing compound selected from the following (A1)-(A6). The third refrigerating machine oil composition of the invention comprises a predetermined base oil, and at least one oxygen-containing compound selected from the following (A1), (A2), (A4), (A7) and (A8).

Abstract: The lubricating base oil of the invention is characterized by having an urea adduct value of not greater than 4% by mass and a viscosity index of 100 or greater. The process for production of a lubricating base oil according to the invention is characterized by comprising a step of hydrocracking/hydroisomerization of a stock oil containing normal paraffins, until the obtained treatment product has an urea adduct value of not greater than 4% by mass and a viscosity index of 100 or greater. A lubricating oil composition according to the invention is characterized by comprising the lubricating base oil of the invention.

Abstract: A viscosity index improver of the present invention contains a star polymer obtained by a reaction of divinylbenzene with alkyl methacrylate containing stearyl methacrylate, the star polymer having a core part and an arm part, wherein the core part is derived from the divinylbenzene and the arm part is a polymer chain of the alkyl methacrylate. A lubricant oil additive and a lubricant oil composition of the present invention contain the above viscosity index improver.

Abstract: The hydrocarbon-based lubricating base oil of the invention has a urea adduct value of not greater than 4% by mass, a viscosity index of 100 or greater, and a cycloparaffin content of 30-60% by mass based on the total amount of the saturated components, as measured by field desorption/ionization mass spectrometry. The hydrocarbon-based lubricating base oil of the invention allows high levels of both viscosity-temperature characteristic and low-temperature viscosity characteristic to be obtained, and exhibits excellence in terms of evaporation property and energy efficiency.

Abstract: A hydrocarbon-based lubricating base oil wherein a urea adduct value is not greater than 4% by mass, a viscosity index is 100 or higher, an average of carbon atoms number is 23-31 as determined by gas chromatography distillation, a value obtained by dividing an integral value of a peak in 30 ppm by an integral value of total peaks in the range of from 0 ppm to 50 ppm for the 13C-NMR spectrum is 0.1-0.2, and a product of a value obtained by dividing an integral value of peaks attributed to tertiary carbon atoms by an integral value of total peaks in the range of from 0 ppm to 50 ppm for the 13C-NMR spectrum, and the average of carbon atoms number, is 1.8-2.5.

Abstract: The shock absorber fluid according to the invention is characterized by comprising a lubricating base oil that has a urea adduct value of not greater than 4% by mass and a viscosity index of 100 or greater. The shock absorber fluid according to the invention can exhibit a high level of all properties including viscosity-temperature characteristic, shear stability and antifoaming property.

Abstract: A lubricating oil composition comprising: a lubricating base oil comprising a first lubricating base oil component having a urea adduct value of not greater than 4% by mass, a kinematic viscosity at 40° C. of 14-25 mm2/s and a viscosity index of 120 or higher and a second lubricating base oil component having a kinematic viscosity at 40° C. of less than 14 mm2/s, wherein the content of the first lubricating base oil component is 10-99% by mass and the content of the second lubricating base oil component is 1-50% by mass, based on the total amount of the lubricating base oil; and a viscosity index improver, the lubricating oil composition having a kinematic viscosity at 100° C. of 4-12 mm2/s and a viscosity index of 200-350.

Abstract: The lubricating oil composition for an internal combustion engine of the invention comprises a lubricating base oil having a urea adduct value of not greater than 4% by mass and a viscosity index of 100 or greater, an ash-free antioxidant containing no sulfur as a constituent element, and at least one compound selected from among ash-free antioxidants containing sulfur as a constituent element and organic molybdenum compounds.

Abstract: The present invention provides a lubricating base oil comprising saturated components of 90% by mass or greater, wherein the proportion of cyclic saturated components among the saturated components is not greater than 40% by mass, and by having a viscosity index of 110 or higher and an iodine value of not greater than 2.5. The lubricating base oil of the invention exhibits excellent viscosity-temperature characteristics and heat and oxidation stability while also allowing additives to exhibit a higher level of function when additives are included. The lubricating base oil of the invention is suitable for use in various lubricating oil fields, and is especially useful for reducing energy loss and achieving energy savings in devices in which the lubricating base oil is applied.

Abstract: The present invention provides a succinimide compound represented by the following formula (1-1) or (1-2), and a lubricating oil additive and a lubricating oil composition which contain the succinimide compound. wherein R represents an alkyl group or an alkenyl group having a number-average molecular weight of 500 or greater and less than 5000. wherein R represents an alkyl group or an alkenyl group having a number-average molecular weight of 500 or greater and less than 5000.

Abstract: The present invention provides a refrigerating machine oil, a compressor oil composition, a hydraulic oil composition, a metalworking oil composition, a heat treating oil composition, a lubricating oil composition for machine tools and a lubricating oil composition which comprise a lubricating oil base oil having % CA of not more than 2, % CP/% CN of not less than 6 and an iodine value of not more than 2.5.

Abstract: The present invention provides a refrigerating machine oil, a compressor oil composition, a hydraulic oil composition, a metalworking oil composition, a heat treating oil composition, a lubricating oil composition for machine tools and a lubricating oil composition which comprise a lubricating oil base oil having % CA of not more than 2, % CP/% CN of not less than 6 and an iodine value of not more than 2.5.

Abstract: The present invention provides a refrigerating machine oil, a compressor oil composition, a hydraulic oil composition, a metalworking oil composition, a heat treating oil composition, a lubricating oil composition for machine tools and a lubricating oil composition which comprise a lubricating oil base oil having % CA of not more than 2, % CP/% CN of not less than 6 and an iodine value of not more than 2.5.

Abstract: The present invention provides a refrigerating machine oil, a compressor oil composition, a hydraulic oil composition, a metalworking oil composition, a heat treating oil composition, a lubricating oil composition for machine tools and a lubricating oil composition which comprise a lubricating oil base oil having % CA of not more than 2, % CP/% CN of not less than 6 and an iodine value of not more than 2.5.

Abstract: The present invention provides a refrigerating machine oil, a compressor oil composition, a hydraulic oil composition, a metalworking oil composition, a heat treating oil composition, a lubricating oil composition for machine tools and a lubricating oil composition which comprise a lubricating oil base oil having % CA of not more than 2, % CP/% CN of not less than 6 and an iodine value of not more than 2.5.

Abstract: The present invention provides a refrigerating machine oil, a compressor oil composition, a hydraulic oil composition, a metalworking oil composition, a heat treating oil composition, a lubricating oil composition for machine tools and a lubricating oil composition which comprise a lubricating oil base oil having % CA of not more than 2, % CP/% CN of not less than 6 and an iodine value of not more than 2.5.