Disclosed is a lubricating oil composition containing a base oil, a viscosity index improver, a molybdenum-based friction modifier, a boron-containing dispersant, and at least two extreme-pressure additives selected from a sulfur-based extreme-pressure additive, a phosphorous-based extreme-pressure additive and a sulfur/phosphorus-based extreme-pressure additive, or a sulfur/phosphorus-based extreme-pressure additive. The base oil is a synthetic oil having a kinematic viscosity at 100° C. of 3 mm.sup.2/s or more and 10 mm.sup.2/s or less, the viscosity index improver is a resin having a number average molecular weight (Mn) of 1,000 or more and 10,000 or less, the mass ratio of boron atoms (B) contained in the boron-containing dispersant to molybdenum atoms (Mo) contained in the molybdenum-based friction modifier, [(B)/(Mo)] is 1 or more and 5 or less, and the mass ratio of sulfur atoms (S) to phosphorus atoms (P) contained in the extreme-pressure additive(s), [(S)/(P)] is 10 or more and 20 or less.

An aspect of the present invention relates to a refrigerating machine oil with a kinematic viscosity at 100° C. of 0.5 mm.sup.2/s or more and 1.5 mm.sup.2/s or less, a 90% distillation temperature in gas chromatography distillation of 280° C. or more and less than 360° C., and an aniline point of 70° C. or more.

The present invention provides a class of halogen-containing synthetic base oils, and preparation method and use thereof. The synthetic base oils have introduced with halogen, especially fluorine, wherein the dipole motion of the halogen groups results in dipole interaction between the dipoles of other components and the base oil molecules of dipole-dipole and dipole-induced halogen (especially fluorine), and the interaction force is stronger and more localized than the dispersion force between the molecules of pure hydrocarbon synthetic oils, and thus the performance of the base oils is directly affected. It solved the problem of oil solubility of pure hydrocarbon synthetic oils, and also improved the properties of oxidation resistance and thermal stability.

Provided is a lubricating oil composition for a refrigerator which uses a base oil including as the main component at least one kind of oxygen-containing compounds selected from polyoxyalkylene glycols, polyvinyl ethers, copolymers of poly(oxy)alkylene glycols or monoethers thereof and polyvinyl ethers, polyol esters, and polycarbonates. The lubricating oil composition for a refrigerator is used for a refrigerator that uses, as a refrigerant, a fluorine-containing organic compound, which is a refrigerant applicable to current car air conditioner systems or the like and has a specific polar structure, and has favorable sealing property, a low coefficient of friction factor in a sliding part, and excellent stability as well as excellent compatibility with the refrigerant.

A hydraulic lubricating oil composition is provided which contains a synergistic mixture of three phosphorous antiwear components in order to provide good thermal stability and good demulsibility to the lubricating oil composition.

The invention provides a lubricating composition comprising a low viscosity base oil and a synergistic mixture of a functionalized ethylene-α-olefin copolymer, a poly(meth)acrylate polymer, and a metal-free anti-wear agent. The invention also provides a method of lubricating an internal combustion engine using such a lubricating composition.

A refrigerator oil composition containing an epoxy compound (X) having at least one of an olefin skeleton and a terpene skeleton, and a base oil (Y).

Lubricant grease compositions comprising a silicone base stock oil having a kinematic viscosity of from 20,000 to 100,000 mm.sup.2/s at 25° C., a metal salt of a fatty acid wherein the metal is selected from the group of lithium, calcium, aluminium, barium titanium, zinc, magnesium and/or sodium; and a suitable anti-wear additive.

The present invention relates to a hydraulic fluid composition containing a base oil (A), an antioxidant (B) including an amine-based antioxidant (B1) and a phenol-based antioxidant (B2), and a succinimide-based compound (C), wherein the hydraulic fluid composition satisfies the following requirement (I): and is to be used for hydraulic equipment which is equipped with at least one of a wet type brake and a wet type clutch and which is selected from a construction machinery, a general industrial machinery, and a power generator, and in which a working pressure is 30 MPa or more. The hydraulic fluid composition is not only excellent in wear resistance and an effect for suppressing the sludge formation but also excellent in a braking performance or a clutch performance, even when used under a high-pressure condition.

Requirement (I): A static friction coefficient (μ.sub.s) after 1,000 cycles, as measured in conformity with the SAE No. 2 test described in JCMAS P 047:2004, is 0.100 to 0.162.

The present invention relates to a lubricating oil composition containing a mineral oil (A) containing 30% by mass or more of a bright stock (A1) on the basis of the total amount of the lubricating oil composition, wherein the lubricating oil composition further contains a synthetic oil (B) and a phosphoric acid ester (C), the content of the synthetic oil (B) is less than 70% by mass on the basis of the total amount of the lubricating oil composition, the content of the phosphoric acid ester (C) as expressed in terms of a phosphorus atom is 0.050 to 0.200% by mass on the basis of the total amount of the lubricating oil composition, and a viscosity index is 150 or more, thereby providing a lubricating oil composition having low temperature dependence and favorable lubricating characteristics even in the case of using the mineral oil containing a bright stock.