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.

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-α-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 present invention relates to a composition for cooling a propulsion system of an electric or hybrid vehicle including at least one battery, comprising: (i) at least one base oil or at least one hydrocarbon-based fluid with a boiling point of greater than or equal to 50° C.; (ii) at least one fire retardant corresponding to formula (I)

R.sub.F-L-R.sub.H  (I)

in which R.sub.F is a perfluorinated or partially fluorinated group, R.sub.H is a hydrocarbon-based group, and L is a linker; and (iii) at least one fluoro compound with a boiling point of between 50 and 250° C.

The invention also relates to the use of at least one fluoro compound with a boiling point of between 50° C. and 250° C. for promoting the contact between a fire retardant corresponding to formula (I) and an element of a propulsion system of an electric or hybrid vehicle, when thermal runaway is observed, said fire retardant of formula (I) being formulated in a base oil, or a hydrocarbon-based fluid with a boiling point of greater than or equal to 50° C.

Finally, the invention relates to a process for cooling and fire-protecting at least one battery of a propulsion system of an electric or hybrid vehicle, comprising at least one step of placing at least one battery in contact with a composition according to the invention.

The present invention relates to a composition for cooling a propulsion system of an electric or hybrid vehicle including at least one battery, comprising: (i) at least one base oil or at least one hydrocarbon-based fluid with a boiling point of greater than or equal to 50° C.; (ii) at least one fire retardant corresponding to formula (I)

R.sub.F-L-R.sub.H  (I)

in which R.sub.F is a perfluorinated or partially fluorinated group, R.sub.H is a hydrocarbon-based group, and L is a linker; and (iii) at least one fluoro compound with a boiling point of between 50 and 250° C.

The invention also relates to the use of at least one fluoro compound with a boiling point of between 50° C. and 250° C. for promoting the contact between a fire retardant corresponding to formula (I) and an element of a propulsion system of an electric or hybrid vehicle, when thermal runaway is observed, said fire retardant of formula (I) being formulated in a base oil, or a hydrocarbon-based fluid with a boiling point of greater than or equal to 50° C.

Finally, the invention relates to a process for cooling and fire-protecting at least one battery of a propulsion system of an electric or hybrid vehicle, comprising at least one step of placing at least one battery in contact with a composition according to the invention.

A lubricating oil composition for a sliding guide surface, which includes a lubricant base oil, an acid phosphate ester mixture having a structure represented by the following Formula (1) and including an acid phosphate monoester and an acid phosphate diester, and an aliphatic monoamine, and which satisfies a predetermined condition A or condition B, is provided. In Formula (1), each of R.sup.1 and R.sup.2 represents a hydrogen atom or a saturated or unsaturated straight-chain aliphatic hydrocarbon group having from 1 to 30 carbon atoms, and R.sup.1 and R.sup.2 are not simultaneously hydrogen atoms.
(R.sup.1O)(R.sup.2O)(HO)P═O  (1)

A lubricating oil composition for a sliding guide surface, which includes a lubricant base oil, an acid phosphate ester mixture having a structure represented by the following Formula (1) and including an acid phosphate monoester and an acid phosphate diester, and an aliphatic monoamine, and which satisfies a predetermined condition A or condition B, is provided. In Formula (1), each of R.sup.1 and R.sup.2 represents a hydrogen atom or a saturated or unsaturated straight-chain aliphatic hydrocarbon group having from 1 to 30 carbon atoms, and R.sup.1 and R.sup.2 are not simultaneously hydrogen atoms.
(R.sup.1O)(R.sup.2O)(HO)P═O  (1)

Lubricant compositions comprising a base oil, one or more antioxidants selected from a group consisting of N-α-naphthyl-N-phenylamine antioxidants and diphenylamine antioxidants; and a sulfur-containing additive comprising up to seven carbon atoms exhibit outstanding oxidative stability and non-corrosion properties. The N-α-naphthyl-N-phenylamine antioxidants plus diphenylamine antioxidants in total may be present from about 0.2 wt % to about 0.8 wt %, based on the total weight of the lubricant composition. The sulfur provided by the sulfur-containing additive may be present from about 50 ppm to about 1000 ppm by weight, based on the total weight of the lubricant composition.

Lubricant compositions comprising a base oil, one or more antioxidants selected from a group consisting of N-α-naphthyl-N-phenylamine antioxidants and diphenylamine antioxidants; and a sulfur-containing additive comprising up to seven carbon atoms exhibit outstanding oxidative stability and non-corrosion properties. The N-α-naphthyl-N-phenylamine antioxidants plus diphenylamine antioxidants in total may be present from about 0.2 wt % to about 0.8 wt %, based on the total weight of the lubricant composition. The sulfur provided by the sulfur-containing additive may be present from about 50 ppm to about 1000 ppm by weight, based on the total weight of the lubricant composition.

An object of the present invention is to provide a dialkyl sulfide which can effectively form a metal sulfide film on a metal surface even in a low-temperature environment, has excellent storage stability, and is suitable as an extreme-pressure additive. The present invention provides a dialkyl sulfide represented by general formula (1) below (in the formula, R.sup.1 and R.sup.2 each independently represent an alkyl group, and n is an integer), wherein the content of a compound having an n value of 1 in the general formula (1) is 10.0% by mass or less relative to the total amount of compounds represented by the general formula (1) ##STR00001##

An object of the present invention is to provide a dialkyl sulfide which can effectively form a metal sulfide film on a metal surface even in a low-temperature environment, has excellent storage stability, and is suitable as an extreme-pressure additive. The present invention provides a dialkyl sulfide represented by general formula (1) below (in the formula, R.sup.1 and R.sup.2 each independently represent an alkyl group, and n is an integer), wherein the content of a compound having an n value of 1 in the general formula (1) is 10.0% by mass or less relative to the total amount of compounds represented by the general formula (1) ##STR00001##