The present invention provides a fluorine-containing ether compound that can form a lubricating layer which has excellent wear resistance even if the thickness is thin and in which a decrease in film thickness due to spin-off is less likely to occur. The fluorine-containing ether compound is represented by the following formula. R.sup.1R.sup.2OCH.sub.2R.sup.3CH.sub.2OR.sup.4R.sup.5 (R.sup.3 is a perfluoropolyether chain. R.sup.1 and R.sup.5 are either an alkyl group which may have a substituent or a hydrocarbon group having a double bond or triple bond. R.sup.2 and R.sup.4 are each a divalent linking group containing one or more heteroatoms, and have one or more polar groups, and the terminal end on the side bonded to R.sup.1 and R.sup.5 is a heteroatom. At least one of R.sup.2 and R.sup.4 contains one or more secondary amine structures. At least one of R.sup.1R.sup.2 and R.sup.4R.sup.5 contains one or more cyano groups).

The present invention provides a fluorine-containing ether compound that can form a lubricating layer which has excellent wear resistance even if the thickness is thin and in which a decrease in film thickness due to spin-off is less likely to occur. The fluorine-containing ether compound is represented by the following formula. R.sup.1R.sup.2OCH.sub.2R.sup.3CH.sub.2OR.sup.4R.sup.5 (R.sup.3 is a perfluoropolyether chain. R.sup.1 and R.sup.5 are either an alkyl group which may have a substituent or a hydrocarbon group having a double bond or triple bond. R.sup.2 and R.sup.4 are each a divalent linking group containing one or more heteroatoms, and have one or more polar groups, and the terminal end on the side bonded to R.sup.1 and R.sup.5 is a heteroatom. At least one of R.sup.2 and R.sup.4 contains one or more secondary amine structures. At least one of R.sup.1R.sup.2 and R.sup.4R.sup.5 contains one or more cyano groups).

A stable lubricant emulsion composition for use in engine and gear applications is provided. The emulsion includes a base petroleum oil, an aqueous salt solution that functions as a friction/wear modifier, and a polymeric non-ionic surfactant composition having a hydrophilic-lipophilic balance value in the range of 2.5 to 7 and an average molecular weight in the range of 1,000 to 3,000. The surfactant composition may include a polyester surfactant, a PIB succinimide surfactant, a PIB amine surfactant, or a mixture thereof.

A stable lubricant emulsion composition for use in engine and gear applications is provided. The emulsion includes a base petroleum oil, an aqueous salt solution that functions as a friction/wear modifier, and a polymeric non-ionic surfactant composition having a hydrophilic-lipophilic balance value in the range of 2.5 to 7 and an average molecular weight in the range of 1,000 to 3,000. The surfactant composition may include a polyester surfactant, a PIB succinimide surfactant, a PIB amine surfactant, or a mixture thereof.

The present invention relates to a Fischer-Tropsch derived residual base oil having a kinematic viscosity at 100 C. according to ASTM D445 in the range of from 15 to 35 mm.sup.2/s, an average number of carbon atoms per molecule Fischer-Tropsch derived residual base oil according to .sup.13C-NMR in a range of from 25 to 50.

To provide a lubricating oil composition for internal combustion engines, which can realize low friction in both internal combustion engines equipped with a DLC and internal combustion engines not equipped with a DLC. [Solution] a lubricating oil composition for internal combustion engines, which is characterized in that the lubricating oil composition for internal combustion engines is a composition obtained by blending a molybdenum dithiocarbamate (MoDTC) and a polyalkylene glycol (PAG) in a base oil, the weight average molecular weight of the polyalkylene glycol is 2750-4500 and the content of the polyalkylene glycol is not less than 0.05 mass % and less than 10 mass % relative to the total mass of the composition.

To provide a lubricating oil composition for internal combustion engines, which can realize low friction in both internal combustion engines equipped with a DLC and internal combustion engines not equipped with a DLC. [Solution] a lubricating oil composition for internal combustion engines, which is characterized in that the lubricating oil composition for internal combustion engines is a composition obtained by blending a molybdenum dithiocarbamate (MoDTC) and a polyalkylene glycol (PAG) in a base oil, the weight average molecular weight of the polyalkylene glycol is 2750-4500 and the content of the polyalkylene glycol is not less than 0.05 mass % and less than 10 mass % relative to the total mass of the composition.

(1) A cylinder lubricating oil composition for a crosshead diesel engine, the composition having a sulfated ash content of 2.0 to 5.5 mass %; a base number of 15 to 45 mgKOH/g; and an autoignition temperature of no less than 262? C. (2) A cylinder lubricating oil composition for a crosshead diesel engine, comprising: a lubricant base oil; (B) a Ca sulfonate detergent having a base number of no less than 10 mgKOH/g and less than 60 mgKOH/g; (C) a Ca phenate detergent having a base number of 55 to 200 mgKOH/g; (D) an amine antioxidant; and (E) a zinc dithiophosphate, wherein the composition has a base number of no less than 15 mgKOH/g and less than 120 mgKOH/g.

(1) A cylinder lubricating oil composition for a crosshead diesel engine, the composition having a sulfated ash content of 2.0 to 5.5 mass %; a base number of 15 to 45 mgKOH/g; and an autoignition temperature of no less than 262? C. (2) A cylinder lubricating oil composition for a crosshead diesel engine, comprising: a lubricant base oil; (B) a Ca sulfonate detergent having a base number of no less than 10 mgKOH/g and less than 60 mgKOH/g; (C) a Ca phenate detergent having a base number of 55 to 200 mgKOH/g; (D) an amine antioxidant; and (E) a zinc dithiophosphate, wherein the composition has a base number of no less than 15 mgKOH/g and less than 120 mgKOH/g.

An oil composition comprising a first component having pendant groups and a second component but free of a third component and process for making such oil composition, where a single molecule of the third component can form large shearable stable complex structure with two molecules of the first component via van der Waals force between pendant groups and the terminal carbon chains, and a single molecule of the second component is capable of adjoining no more than one molecule of the first type. The oil composition has high shear stability making it suitable for use in lubricants subject to repeated high shear stress events.