JP2020164588A - Lubricant composition - Google Patents

Abstract

To provide the lubricant composition that can maintain a higher intermetallic friction coefficient under a medium surface pressure condition, and further can reduce an intermetallic friction coefficient under a low surface pressure condition.SOLUTION: The lubricant composition comprises: a lubricant base oil, (A) a calcium-based cleaning agent having a base value of more than 100 mgKOH/g; (B) a phosphite ester-based anti-wear agent, and (C) amino acids and/or derivatives thereof having an alkyl, alkenyl or acyl group having 6 to 24 carbon atoms.SELECTED DRAWING: None

Description

The present invention relates to a lubricating oil composition, and more particularly to a lubricating oil composition that can be preferably used for lubricating a continuously variable transmission.

Push belt type continuously variable transmissions are rapidly becoming widespread in recent years because they are effective in improving fuel efficiency of automobiles. The push belt type continuously variable transmission includes a pair of pulleys including a drive pulley and a driven pulley, and a metal belt wound around the pair of pulleys, and the metal belt is sandwiched between the pulleys and released. A plurality of metal elements (transverse elements; coma) that orbit around the pair of pulleys while repeating the above, and at least one ring-shaped metal band that holds the plurality of metal elements on the path of the orbital movement. (Carrier) and. Power is transmitted from the input side (drive pulley) to the output side (driven pulley) by the drive pulley sandwiching the piece held by the carrier of the metal belt and pushing it toward the driven pulley. The gear ratio is controlled by adjusting the radius of the arcuate movement path of the metal element in one or both pulleys. The radius of the movement path is adjusted by changing the distance between the pair of conical surfaces (sheaves) in which the pulley sandwiches the metal element. In order to increase the transmitted torque capacity of the metal belt, the surface pressure between the metal element and the sheave is usually maintained higher than the surface pressure at other sliding parts (excluding the gear tooth surface). That is, the surface pressure at other sliding parts (excluding the gear tooth surface) is a low surface pressure (for example, about 1 to 10 MPa), whereas the surface pressure between the metal element and the sheave is a medium surface pressure (for example, about 1 to 10 MPa). For example, it is maintained at 0.1 GPa or more and less than 1 GPa).

JP-A-10-306292

One approach to energy saving in transmissions is to reduce the size and weight of the transmission. By reducing the size and weight of the transmission, the fuel efficiency of the vehicle equipped with the transmission will be improved. Especially for push belt type continuously variable transmissions, if the friction coefficient (coefficient of friction between metals) under the intermediate surface pressure condition between the metal element and the sheave can be increased, (1) the hydraulic pressure from the oil pump is lowered. Therefore, the oil pump can be miniaturized, and (2) the transmission can be miniaturized without impairing the transmission torque capacity of the metal belt. Therefore, it is desirable that the lubricating oil used in the continuously variable transmission keeps a high coefficient of friction between metals under medium surface pressure conditions. On the other hand, from the viewpoint of reducing friction loss at other sliding parts and improving fuel efficiency, it is desirable that the coefficient of friction between metals is low under low surface pressure conditions.

However, in general, in a lubricating oil having a high coefficient of friction between metals under medium surface pressure conditions, the coefficient of friction between metals tends to be high under low surface pressure conditions, and the coefficient of friction between metals under low surface pressure conditions tends to be high. With a lower lubricating oil, the coefficient of friction between metals also tends to be lower under medium surface pressure conditions.

An object of the present invention is to provide a lubricating oil composition capable of further reducing the coefficient of friction between metals under low surface pressure conditions while maintaining a higher coefficient of friction between metals under medium surface pressure conditions. And.

One embodiment of the present invention includes a lubricating oil base oil, (A) a calcium-based cleaning agent having a base value of more than 100 mgKOH / g, (B) a phosphite ester-based abrasion inhibitor, and (C) 6 carbon atoms. A lubricating oil composition comprising ~ 24 alkyl or alkenyl or an amino acid having an acyl group and / or a derivative thereof.

In the lubricating oil composition, the component (A) is preferably a calcium sulfonate cleaning agent having a base value of more than 100 mgKOH / g.

The lubricating oil composition of the present invention can be preferably used as a lubricating oil composition for continuously variable transmissions.

According to the present invention, there is provided a lubricating oil composition capable of further reducing the coefficient of friction between metals under low surface pressure conditions while maintaining a higher coefficient of friction between metals under medium surface pressure conditions. Can be done.

Hereinafter, the present invention will be described in detail. In this specification, unless otherwise specified, the notation "A to B" for the numerical values A and B is equivalent to "A or more and B or less". When a unit is attached only to the numerical value B in such a notation, the unit shall be applied to the numerical value A as well. In the present specification, the terms "or" and "or" shall mean OR unless otherwise specified. In the present specification, the notation "E ₁ and / or E ₂ " for the elements E ₁ and E ₂ is equivalent to "E ₁ , or E ₂ , or a combination thereof", and N elements E ₁ , ... (N is an integer of 3 or more.) _E N for _{"E 1,} ..., and / or _{E N"} notation is _{"E 1,} ..., or _{E N,} or combinations thereof," to be equivalent.

<Lubricating oil base oil>
The lubricating oil base oil in the lubricating oil composition of the present invention (hereinafter, may be referred to as “lubricating oil composition” or simply “composition”) includes Group II base oil and Group III base oil classified as API base oil. , Group IV base oil, Group V base oil, or a mixed base oil thereof can be used without particular limitation. The API group II base oil is a mineral oil-based base oil having a sulfur content of 0.03% by mass or less, a saturation content of 90% by mass or more, and a viscosity index of 80 or more and less than 120. The API group III base oil is a mineral oil-based base oil having a sulfur content of 0.03% by mass or less, a saturation content of 90% by mass or more, and a viscosity index of 120 or more. The API Group IV base oil is a poly α-olefin base oil. The API Group V base oil is an ester-based base oil.

As the mineral oil-based base oil, solvent desorption, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, and hydrorefining of the lubricating oil distillate obtained by atmospheric distillation and vacuum distillation of crude oil are carried out. , Paraffin-based or naphthen-based mineral oil-based base oils, which are obtained by appropriately combining one or more kinds of purification means such as sulfuric acid washing and white clay treatment. API Group II base oils and Group III base oils are usually produced through a hydrocracking process. Further, a wax isomerized base oil, a base oil produced by a method of isomerizing GTL WAX (gas to liquid wax), and the like can also be used.

Examples of the API group IV base oil include ethylene-propylene copolymers, polybutenes, 1-octene oligomers, 1-decene oligomers, and hydrides thereof.

API group V base oils include, for example, monoesters (eg, butylstearate, octyllaurate); diesters (eg, ditridecylglutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, di-2-ethylhexyl sepa). Kate, etc.); Polyester (eg, trimellitic acid ester, etc.); Polyester ester (eg, trimethylolpropane caprilate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate, pentaerythritol pelargonate, etc.) Can be done.

The lubricating oil base oil may consist of one type of base oil or may be a mixed base oil containing two or more types of base oils. In a mixed base oil containing two or more kinds of base oils, the API classifications of the base oils may be the same or different from each other. In one embodiment, the lubricating oil base oil is an API Group II base oil, or an API Group III base oil, or an API Group IV base oil, or a combination thereof.

The kinematic viscosity of the lubricating oil base oil at 100 ° C. is preferably 2.5 to 5.0 mm ² / s, more preferably 3.3 to 4.7 mm ² / s, still more preferably 3.8 to 4.5 mm. ^{It is 2} / s. When the kinematic viscosity of the lubricating oil base oil at 100 ° C. is not more than the above upper limit value, it is possible to improve fuel efficiency. Further, when the kinematic viscosity of the lubricating oil base oil at 100 ° C. is at least the above lower limit value, it is possible to sufficiently form an oil film at the lubricated portion and improve the lubricity. In the present specification, the "kinematic viscosity at 100 ° C." means the kinematic viscosity at 100 ° C. defined in ASTM D-445.

The kinematic viscosity of the lubricating oil base oil at 40 ° C. is preferably 8.5 to 30.0 mm ² / s, more preferably 12.0 to 28.0 mm ² / s, still more preferably 15.0 to 25. It is 0 mm ² / s or less. When the kinematic viscosity of the lubricating oil base oil at 40 ° C. is not more than the above upper limit value, it is possible to improve fuel efficiency. Further, when the kinematic viscosity of the lubricating oil base oil at 40 ° C. is at least the above lower limit value, it is possible to sufficiently form an oil film at the lubricated portion and improve the lubricity. In the present specification, the "kinematic viscosity at 40 ° C." means the kinematic viscosity at 40 ° C. defined in ASTM D-445.

The viscosity index of the lubricating oil base oil is preferably 100 or more, more preferably 105 or more, and in one embodiment, it may be 110 or more, 120 or more, or 125 or more. .. When the viscosity index of the lubricating oil base oil is at least the above lower limit value, it is possible to improve the viscosity-temperature characteristics, thermal / oxidation stability, and wear prevention property of the lubricating oil composition. In addition, in this specification, a viscosity index means a viscosity index measured according to JIS K 2283-1993.

The content of sulfur in the lubricating oil base oil is preferably 0.03 mass% (300 mass ppm) or less, more preferably 50 mass ppm or less, and particularly preferably 10 mass ppm or less from the viewpoint of oxidative stability. It may be 1 mass ppm or less.

The content of the lubricating oil base oil (total base oil) in the lubricating oil composition is preferably 70 to 99.3% by mass, more preferably 80 to 99.3% by mass, based on the total amount of the lubricating oil composition. It can be 85-99.3% by mass in the embodiment of.

<(A) Calcium-based cleaning agent>
The lubricating oil composition of the present invention contains (A) a calcium-based cleaning agent having a base value of more than 100 mgKOH / g (hereinafter, may be simply referred to as "component (A)"). As the component (A), known calcium-based cleaning agents such as calcium sulfonate cleaning agent, calcium salicylate cleaning agent, and calcium phenate cleaning agent can be used, and the calcium sulfonate cleaning agent can be preferably used. As the component (A), one kind of cleaning agent may be used alone, or two or more kinds of cleaning agents may be used in combination.

Preferred examples of the calcium sulfonate cleaning agent include a calcium salt of an alkyl aromatic sulfonic acid obtained by sulfonated an alkyl aromatic compound, or a basic salt or a hyperbasic salt thereof. The weight average molecular weight of the alkyl aromatic compound is preferably 400 to 1500, more preferably 700 to 1300.
Examples of the alkyl aromatic sulfonic acid include so-called petroleum sulfonic acid and synthetic sulfonic acid. Examples of the petroleum sulfonic acid referred to here include sulfonated alkyl aromatic compounds of the lubricating oil fraction of mineral oil, so-called mahoganic acid, which is by-produced during the production of white oil. Further, as an example of synthetic sulfonic acid, a linear or branched alkyl obtained by recovering a by-product in an alkylbenzene production plant which is a raw material of a detergent or by alkylating benzene with polyolefin. Examples thereof include sulfonated alkylbenzenes having a group. As another example of the synthetic sulfonic acid, sulfonated alkylnaphthalene such as dinonylnaphthalene can be mentioned. Further, the sulfonate agent for sulfonated these alkyl aromatic compounds is not particularly limited, and for example, fuming sulfuric acid or anhydrous sulfuric acid can be used.

Preferred examples of the calcium salicylate cleaning agent include calcium salicylate or a basic salt or a hyperbasic salt thereof. A preferable example of calcium salicylate is a compound represented by the following general formula (1).

In the general formula (1), R ¹ independently represents an alkyl group or an alkenyl group having 14 to 30 carbon atoms. a represents 1 or 2, preferably 1. When a = 2, R ¹ may be a combination of different groups.

The method for producing calcium salicylate is not particularly limited, and a known method for producing monoalkyl salicylate or the like can be used. For example, phenol is used as a starting material, and olefins are used for alkylation, and then monoalkylsalicylic acid obtained by carboxylating with carbon dioxide or the like, or salicylic acid is used as a starting material, and an equivalent amount of the above olefins is used for alkylation. The obtained monoalkylsalicylic acid or the like is reacted with a metal base such as a calcium oxide or a hydroxide, or these monoalkylsalicylic acids or the like are once converted into an alkali metal salt such as a sodium salt or a potassium salt and then a calcium salt. Calcium salicylate can be obtained by exchanging metal with and the like.

A preferred example of the phenate-based cleaning agent is a hyperbasic salt of a calcium salt of a compound having a structure represented by the following general formula (2).

In the general formula (2), R ² represents a linear or branched chain having 6 to 21 carbon atoms, a saturated or unsaturated alkyl group or an alkenyl group, and b represents a degree of polymerization and represents an integer of 1 to 10. A represents a sulfide (-S-) group or a methylene (-CH _2- ) group, and c represents an integer of 1 to 3. R ² may be a combination of two or more different groups.

The carbon number of R ² in the general formula (2) is preferably 9 to 18, more preferably 9 to 15. When the carbon number of R ² is at least the above lower limit value, it becomes possible to enhance the solubility in the base oil. Further, when the carbon number of R ² is not more than the above upper limit value, the heat resistance can be improved.

The degree of polymerization b in the general formula (2) is preferably 1 to 3. When the degree of polymerization b is within this range, the heat resistance can be enhanced.

The method for obtaining the superbasified calcium sulfonate, phenate, or salicylate is not particularly limited, but for example, the calcium sulfonate, phenate, or salicylate is converted into a calcium base (for example, calcium oxide, hydroxide) in the presence of carbon dioxide gas. By reacting with calcium or the like), a hyperbasified calcium sulfonate, phenate, or salicylate can be obtained.

The base value of the component (A) is more than 100 mgKOH / g, preferably more than 100 mgKOH / g and less than 500 mgKOH / g, more preferably 150 to 500 mgKOH / g, still more preferably 200 to 500 mgKOH / g. When the base value of the component (A) is more than 100 mgKOH / g, it is possible to increase the coefficient of friction between metals (transmission torque capacity of the metal belt) under medium surface pressure conditions. In the present specification, the base value means the base value measured by the perchloric acid method as measured in accordance with ASTM D 2896.

The content of the component (A) in the lubricating oil composition is preferably 50 to 1500 mass ppm, more preferably 80 to 1000 mass ppm as the amount of calcium (calcium element equivalent amount) based on the total amount of the lubricating oil composition. , Can be 100-600 mass ppm in one embodiment. When the content of the component (A) is equal to or higher than the above lower limit value, the friction coefficient between metals (transmission torque capacity of the metal belt) under medium surface pressure conditions is maintained or further increased, and between metals under low surface pressure conditions. It is possible to further reduce the coefficient of friction (the coefficient of friction in sliding gears, bearings, etc.). Further, when the content of the component (A) is not more than the above upper limit value, the clutch torque capacity and the shifting characteristic can be maintained satisfactorily for a long period of time.

<(B) Phosphite ester anti-wear agent>
The lubricating oil composition of the present invention contains a phosphite ester-based wear inhibitor (hereinafter, may be referred to as "component (B)"). Examples of the component (B) include a compound represented by the following general formula (3), and a metal salt and an ammonium salt thereof. As the component (B), one kind of compound may be used alone, or two or more kinds of compounds may be used in combination.

（一般式（３）中、Ｘ^１、Ｘ^２、及びＸ^３は、それぞれ独立に酸素原子または硫黄原子を表し；Ｒ^３は炭素数１〜３０の炭化水素基を表し；Ｒ^４及びＲ^５はそれぞれ独立に水素原子または炭素数１〜３０の炭化水素基を表し；Ｒ^３、Ｒ^４、及びＲ^５は同一でも相互に異なっていてもよく；一般式（３）の化合物はタウトマーであってもよい。）

(In general formula (3), X ¹ , X ² , and X ³ independently represent an oxygen atom or a sulfur atom; R ³ represents a hydrocarbon group having 1 to 30 carbon atoms; R ⁴ and R ⁵ Represent each independently a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms; R ³ , R ⁴ , and R ⁵ may be the same or different from each other; the compound of general formula (3) is toutmer. May be.)

Examples of the hydrocarbon group having 1 to 30 carbon atoms in the general formula (3) include an alkyl group, a cycloalkyl group, an alkenyl group, an alkyl-substituted cycloalkyl group, an aryl group, an alkyl-substituted aryl group, and an arylalkyl group. Can be mentioned. The hydrocarbon group is preferably an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 24 carbon atoms, and in one embodiment, an alkyl group having 3 to 18 carbon atoms, more preferably an alkyl group having 4 to 12 carbon atoms. It is an aryl group or an alkylaryl group.

Specific examples of metals forming a metal salt with a phosphorus compound represented by the general formula (3) include alkali metals such as lithium, sodium, potassium and cesium, and alkaline earths such as calcium, magnesium and barium. Examples include metals, heavy metals such as zinc, copper, iron, lead, nickel, silver and manganese. Among these, alkaline earth metals such as calcium and magnesium, zinc, or a combination thereof is preferable.

Examples of the nitrogen-containing compound forming an ammonium salt with the phosphorus compound represented by the general formula (3) include ammonia, monoamine, diamine, polyamine, and alkanolamine. More specifically, a nitrogen-containing compound represented by the following general formula (4); alkylenediamines such as methylenediamine, ethylenediamine, propylenediamine, and butylenediamine; diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine. Et al., And combinations thereof, and the like.

（一般式（４）中、Ｒ^６〜Ｒ^８はそれぞれ独立に、水素原子、炭素数１〜８のヒドロカルビル基、又は水酸基を有する炭素数１〜８のヒドロカルビル基を表し；Ｒ^６〜Ｒ^８のうち少なくとも１つは炭素数１〜８のヒドロカルビル基、又は水酸基を有する炭素数１〜８のヒドロカルビル基である。）

(In the general formula (4), R ^{6 to} R ⁸ independently represent a hydrogen atom, a hydrocarbyl group having 1 to 8 carbon atoms, or a hydrocarbyl group having a hydroxyl group and having 1 to 8 carbon atoms; R ^{6 to} R ⁸ At least one of them is a hydrocarbyl group having 1 to 8 carbon atoms or a hydrocarbyl group having a hydroxyl group and having 1 to 8 carbon atoms.)

Among the above-mentioned compounds, the phosphite ester compound can be preferably used as the phosphorus-containing additive, and among them, an alkyl group, an aryl group, or an alkylaryl group having 3 to 18 carbon atoms (preferably 4 to 12) can be used. Hydrogen phosphite having is particularly preferable. For example, one or more hydrogen phosphites selected from diphenylhydrogenphosphine, triphenylphosphine, dibutylhydrogenphosphine, and dilaurylhydrogenphosphine can be preferably used.

In one embodiment, as the component (B), a compound represented by the following general formula (5) can be preferably used. By using the phosphite ester compound represented by the general formula (5) as the component (B), it becomes possible to enhance the wear resistance and the fatigue resistance.

一般式（５）において、Ｒ^９及びＲ^１０はそれぞれ独立に、水素原子、炭素数１〜１８の直鎖炭化水素基、又は下記一般式（６）で表される炭素数５〜２０の基であり、Ｒ^９及びＲ^１０の少なくとも一方は炭素数１〜１８の直鎖炭化水素基または下記一般式（６）で表される炭素数５〜２０の基である。一の好ましい実施形態において、Ｒ^９及びＲ^１０の両方がそれぞれ独立に炭素数１〜１８の直鎖炭化水素基または下記一般式（６）で表される炭素数５〜２０の基である。

In the general formula (5), R ⁹ and R ¹⁰ are independently hydrogen atoms, linear hydrocarbon groups having 1 to 18 carbon atoms, or groups having 5 to 20 carbon atoms represented by the following general formula (6). At least one of R ⁹ and R ¹⁰ is a linear hydrocarbon group having 1 to 18 carbon atoms or a group having 5 to 20 carbon atoms represented by the following general formula (6). In one preferred embodiment, both R ⁹ and R ¹⁰ are independently linear hydrocarbon groups having 1 to 18 carbon atoms or groups having 5 to 20 carbon atoms represented by the following general formula (6).

一般式（６）において、Ｒ^１１は炭素数２〜１７の直鎖炭化水素基であり、好ましくはエチレン基またはプロピレン基であり、一の実施形態においてエチレン基である。Ｒ^１２は炭素数２〜１７の直鎖炭化水素基であり、好ましくは炭素数２〜１６の直鎖炭化水素基であり、特に好ましくは炭素数６〜１０の直鎖炭化水素基である。Ｘ^４は酸素原子または硫黄原子であり、好ましくは硫黄原子である。

In the general formula (6), R ¹¹ is a linear hydrocarbon group having 2 to 17 carbon atoms, preferably an ethylene group or a propylene group, and in one embodiment, an ethylene group. R ¹² is a linear hydrocarbon group having 2 to 17 carbon atoms, preferably a linear hydrocarbon group having 2 to 16 carbon atoms, and particularly preferably a linear hydrocarbon group having 6 to 10 carbon atoms. X ⁴ is an oxygen atom or a sulfur atom, preferably a sulfur atom.

In one embodiment, preferred examples of R ⁹ and R ¹⁰ include linear alkyl groups having 4 to 18 carbon atoms. Examples of linear alkyl groups include butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group and heptadecyl group. , Octadecyl group can be mentioned.

In one embodiment, preferred examples of R ⁹ and R ¹⁰ are 3-thiapentyl group, 3-thiahexyl group, 3-thiaheptyl group, 3-thiaoctyl group, 3-thianonyl group, 3-thiadecyl group, 3-thiaundesyl. Group, 4-thiahexyl group, 3-oxapentyl group, 3-oxahexyl group, 3-oxaheptyl group, 3-oxaoctyl group, 3-oxanonyl group, 3-oxadecyl group, 3-oxaundecyl group, 3-oxadodecyl Group, 3-oxatridecyl group, 3-oxatetradecyl group, 3-oxapentadecyl group, 3-oxahexadecyl group, 3-oxaheptadecyl group, 3-oxaheptadecyl group, 3-oxanonadecyl group, 4 -Oxahexyl group, 4-oxaheptyl group, and 4-oxaoctyl group can be mentioned.

The content of the component (B) in the lubricating oil composition is preferably 50 to 800 mass ppm, more preferably 50 to 500 mass ppm as the phosphorus content based on the total amount of the lubricating oil composition, and is 100 in one embodiment. It can be ~ 300 mass ppm. When the content of the component (B) is at least the above lower limit value, it is possible to further increase the coefficient of friction between metals under medium surface pressure conditions, and also enhance wear resistance, seizure resistance, and fatigue life. Will be possible. Further, when the content of the component (B) is not more than the above upper limit value, it becomes possible to further reduce the coefficient of friction between metals under low surface pressure conditions, and also wear resistance, seizure resistance, and fatigue life. It becomes possible to increase.

<(C) Ash-free friction modifier>
The lubricating oil composition of the present invention may be an ashless friction modifier, an amino acid having an alkyl or alkenyl having 6 to 24 carbon atoms or an acyl group, and / or a derivative thereof (hereinafter, referred to as "component (C)". ) Is contained. As the component (C), one kind of compound may be used alone, or two or more kinds of compounds may be used in combination. Examples of amino acids having an alkyl or alkenyl or acyl group having 6 to 24 carbon atoms include a compound represented by the following general formula (7).

一般式（７）において、Ｒ^１３は炭素数６〜２４の直鎖又は分岐鎖のアルキル又はアルケニル又はアシル基である。Ｒ^１４は水素原子又は炭素数１〜４の直鎖又は分岐鎖のアルキル基である。Ｒ^１５は官能基を有していてもよく直鎖又は分岐鎖の飽和炭化水素基を含む炭素数１〜１０の炭化水素基、又は水素原子である。ｄは０又は１であり、ｄ＝１のとき、Ｒ^１６は水素原子又は炭素数１〜４の直鎖又は分岐鎖アルキル基である。

In the general formula (7), R ¹³ is a linear or branched chain alkyl, alkenyl or acyl group having 6 to 24 carbon atoms. R ¹⁴ is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms. R ¹⁵ may have a functional group, and is a hydrocarbon group having 1 to 10 carbon atoms including a linear or branched saturated hydrocarbon group, or a hydrogen atom. d is 0 or 1, and when d = 1, R ¹⁶ is a hydrogen atom or a straight or branched chain alkyl group having 1 to 4 carbon atoms.

The carbon number of R ¹³ is 6 to 24, preferably 12 to 24, and more preferably 12 to 18. When the carbon number of R ¹³ is at least the above lower limit value, it becomes possible to increase the solubility in the base oil and reduce the coefficient of friction between metals under low surface pressure conditions. R ¹³ may be a straight chain or a branched chain, but from the viewpoint of further reducing the coefficient of friction between metals under low surface pressure conditions, R ¹³ is a straight chain alkyl, alkenyl or acyl group. Is preferable. Examples of alkyl groups include hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecil group and icosyl group. Examples include a group, a henicosyl group, a docosyl group, a tricosyl group, and a tetracosyl group. Examples of alkenyl groups include hexenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, undecenyl group, dodecenyl group, tridecenyl group, tetradecenyl group, pentadecenyl group, hexadecenyl group, heptadecenyl group, octadecenyl group, nonadesenyl group, icodecenyl group. Examples include a group, a henicosenyl group, a docosenyl group, a tricosenyl group, and a tetracosenyl group. The position of the double bond in the alkenyl group may be any position, but it is preferably other than the α-position (that is, the carbon atom bonded to the nitrogen atom). An example of an acyl group is a linear or branched alkyl or alkenyl group having a methylene group at the α-position in which the methylene group at the α-position (that is, bonded to a nitrogen atom) is replaced with a carbonyl group. Can be mentioned.

R ¹⁴ is a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, preferably a linear or branched alkyl group having 1 to 4 carbon atoms from the viewpoint of storage stability, and more preferably a linear or branched alkyl group having 1 to 4 carbon atoms. It is an alkyl group 1-3, more preferably a methyl group or an ethyl group, and in one embodiment it can be a methyl group.

R ¹⁵ may have a functional group, and is a hydrocarbon group having 1 to 10 carbon atoms including a linear or branched saturated hydrocarbon group, or a hydrogen atom. R ¹⁵ may have a cyclic structure or a heterocyclic structure such as a phenyl group, a phenylene group, an imidazolyl group and an indrill group, and may have a hydroxy group, a carboxy group, an amide bond, an amino group, a mercapto group, a sulfide bond and a guanidino group. It may have a functional group such as. Viewpoint increase the solubility in the base oil, and further in view of reducing the friction coefficient between metals in Teimen圧conditions, R ¹⁵ is preferably methyl or ethyl group or a hydrogen atom, more preferably a methyl group or hydrogen It is an atom, particularly preferably a hydrogen atom.

d is 0 or 1, and when d = 1, R ¹⁶ is a hydrogen atom or a straight or branched chain alkyl group having 1 to 4 carbon atoms. From the viewpoint of storage stability, R ¹⁶ is preferably an alkyl group or a hydrogen atom having 1 to 3 carbon atoms, more preferably a methyl group or an ethyl group or a hydrogen atom, and particularly preferably a hydrogen atom.

One preferred embodiment of the compound represented by the general formula (7) is a compound in which R ¹³ is an aliphatic acyl group and R ¹⁴ is a methyl group, that is, the nitrogen atom of an N-methyl amino acid is acylated with a fatty acid. N-acylated-N-methyl amino acids having the above-mentioned structure can be mentioned. In the compound, R ¹³ is an aliphatic acyl group corresponding to a fatty acid. Such a compound can be obtained as a condensation product, for example, by reacting an N-methyl amino acid with an acylating agent derived from a fatty acid in the presence of a base, if necessary. In the present specification, the "aliphatic acyl group corresponding to the fatty acid" means an acyl group (R-CO- group) obtained by removing the hydroxy group from the carboxy group of the fatty acid (R-CO ₂ H). To do.

The N-methyl amino acid is a compound having a structure in which the amino group of the amino acid (α-amino group when the amino acid is α-amino acid, β-amino group when the amino acid is β-amino acid) is methylated. is there. The N-methyl amino acid may be a mixture of two or more compounds. Examples of amino acids include glycine, alanine, phenylalanine, valine, leucine, isoleucine, serine, threonine, tyrosine, cysteine, methionine, aspartic acid, glutamine, aspartic acid, glutamic acid, tryptophan, lysine, arginine, histidine, ornithine, citrulline, theanine. Α-amino acids such as; and β-amino acids such as β-alanine. The amino acid having an asymmetric center may be a D-form, an L-form, a racemate, or a mixture thereof. Among these amino acids, glycine, alanine, valine, leucine, isoleucine, or β-alanine is preferable, and glycine or β-alanine is particularly preferable.

Examples of fatty acid-derived acylating agents include acid halides of fatty acids (eg, acid salts, acid bromides, etc.), active esters of fatty acids (eg, esters of fatty acids with N-hydroxysuccinimide (NHS), etc.). Esters of fatty acids and 1-hydroxybenzotriazole (HOBt), etc.), acid anhydrides of fatty acids, etc. can be mentioned. As the fatty acid, a fatty acid having 6 to 24 carbon atoms, preferably 8 to 24 carbon atoms, more preferably 12 to 24 carbon atoms, and further preferably 12 to 22 carbon atoms can be used. The fatty acid may be a saturated fatty acid or an unsaturated fatty acid, but is preferably a linear fatty acid. Preferred examples of fatty acids are caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, palmitreic acid, stearic acid, oleic acid, linoleic acid, lignoceric acid, elaidic acid, eleostearic acid, arachidic acid, eicosenoic acid. , Bechenic acid, elaidic acid, lignoceric acid, and mixtures thereof. Fatty acids derived from natural fats and oils may be used as a mixture containing two or more of the above fatty acids. Examples of fatty acids derived from natural fats and oils include coconut oil fatty acids, palm kernel oil fatty acids, palm oil fatty acids, millet oil fatty acids, tall oil fatty acids, corn oil fatty acids, rapeseed oil fatty acids, olive oil fatty acids, sesame oil fatty acids, soybean oil fatty acids, and rice bran. Examples thereof include oil fatty acids, sunflower oil fatty acids, sunflower oil fatty acids, linseed oil fatty acids, fish oil fatty acids, beef fat fatty acids, and mixtures thereof.

In the reaction of the N-methyl amino acid with the acylating agent, if necessary, the amino group of the N-methyl amino acid (α-amino group when the amino acid is α-amino acid, α-amino group when the amino acid is β-amino acid, β-amino acid). The above condensation reaction may be carried out in a state where a protective group is introduced into one or more functional groups (for example, a carboxy group) other than β-amino group), and then deprotection may be carried out if necessary. Examples of the protecting group of the α-carboxy group (β-carboxy group when the amino acid is β-amino acid) include methyl ester, ethyl ester, benzyl ester, tert-butyl ester and the like. Examples of protecting groups for the carboxy group of the aspartic acid and glutamic acid side chains include tert-butyl ester, cyclohexyl ester, and allyl ester. Examples of the protecting group for the alcoholic hydroxy group of the serine and threonine side chains include a benzyl group and a tert-butyl group. Examples of the protecting group for the phenolic hydroxy group of the tyrosine side chain include a 2-bromobenzyloxycarbonyl group, a tert-butyl group and the like. Examples of the protecting group of the mercapto group of the cysteine side chain include a 4-methylbenzyl group, a trityl group, a tert-butyl group and the like. Examples of the protecting group for the guanidine group in the arginine side chain include the p-toluenesulfonyl group. Examples of the protecting group for the imidazolyl group of the histidine side chain include a benzyloxymethyl group, a tert-butoxymethyl group, a 2,4-dinitrophenyl group, a trityl group and the like. Examples of the protecting group for the indole ring of the tryptophan side chain include a formyl group and a tert-butoxycarbonyl group. Known reaction conditions can be applied to the introduction and deprotection of protecting groups.

In another embodiment of the compound represented by the general formula (7), R ¹³ is a linear or branched alkyl or alkenyl group, preferably a linear alkyl or alkenyl group, and R ¹⁴ is methyl. Examples thereof include a compound as a group, that is, an N-alkyl or alkenyl-N-methyl amino acid having a structure in which the nitrogen atom of the N-methyl amino acid is alkylated or alkenylated. Such compounds can be obtained, for example, by reacting an N-methyl amino acid with a linear or branched chain alkyl or alkenyl halide in the presence of a base. As the N-methyl amino acid, the N-methyl amino acid described above can be used. The alkyl or alkenyl halide, can be used with alkyl or alkenyl groups described above in relation to R ^13, a chlorine atom, a bromine atom, an alkyl or alkenyl halide and the halogen atom is bonded to an iodine atom. In one embodiment, as the alkyl or alkenyl halide, the alkyl or alkenyl halide corresponding to the aliphatic alcohol corresponding to the fatty acid described above can be preferably used. In the present specification, the "aliphatic alcohol corresponding to a fatty acid" means an aliphatic alcohol obtained by hydride-reducing the carboxy group of the fatty acid. Further, in the present specification, the "alkyl or alkenyl halide corresponding to the aliphatic alcohol" means an alkyl or alkenyl halide having a structure in which the hydroxy group of the aliphatic alcohol is converted into a halogeno group. In the reaction of N-methyl amino acid with alkyl or alkenyl halide, if necessary, the amino group of N-methyl amino acid (α-amino group when the amino acid is α-amino acid, β-amino acid when the amino acid is β-amino acid) Reacts with the above alkyl or alkenyl halide in a state where a protective group is introduced into one or more functional groups (for example, a carboxy group) other than β-amino group), and then deprotection is performed as necessary. You may go. The protecting groups are as described above.

One typical embodiment of the compound represented by the general formula (7) is N-acylated-N-methylglycine (generally) having a structure in which the amino group of N-methylglycine is acylated with a fatty acid. In the formula (7), R ¹³ is an acyl group corresponding to a fatty acid, R ¹⁴ is a methyl group, R ¹⁵ is a hydrogen atom, and d = 0).
Another typical embodiment of the compound represented by the general formula (7) is N-acylated-N-methyl having a structure in which the amino group of N-methyl-β-alanine is acylated with a fatty acid. -Β-alanine (in the general formula (7), R ¹³ is an acyl group corresponding to a fatty acid, R ¹⁴ is a methyl group, R ¹⁵ is a hydrogen atom, d = 1, R ¹⁶ is a hydrogen atom).

In one embodiment, the compound represented by the general formula (7) can be preferably used as it is as the component (C). In other embodiments, a derivative of the compound represented by the general formula (7) may be used as the component (C), or a compound represented by the general formula (7) and a derivative thereof may be combined as the component (C). May be used. Derivatives of the compound represented by the general formula (7) include metal salts, ethanolamine salts, primary or secondary amides, methyl esters, and polyhydric alcohol esters.

Examples of the metal forming the metal salt with the compound represented by the general formula (7) include alkali metals such as sodium and potassium; alkaline earth metals such as calcium and magnesium; and zinc. From the viewpoint of maintaining the friction adjusting effect for a long period of time, the metal salt is preferably an alkaline earth metal salt or a zinc salt. In this specification, magnesium is included in alkaline earth metals.
The metal salt and ethanolamine salt of the compound represented by the general formula (7) are, for example, the compound represented by the general formula (7), a metal base (for example, a metal oxide, a metal hydroxide, etc.) or ethanolamine. It can be obtained by reacting with a salt.

The methyl ester of the compound represented by the general formula (7) is a carboxy group (α-carboxy group when the amino acid is an α-amino acid, β- when it is a β-amino acid) in the general formula (7). A carboxy group.) Is a derivative converted to a methyl ester. The methyl ester may be obtained, for example, by a condensation reaction between a compound represented by the general formula (7) and methanol, and the amino group of an amino acid methyl ester or an N-alkyl amino acid methyl ester (when the amino acid is an α-amino acid). the α- amino groups, in the case of β- amino acid may be obtained by introducing a substituent R ¹³ on the nitrogen atom of the β- amino group.).

The primary amide of the compound represented by the general formula (7) is a carboxy group in the general formula (7) (α-carboxy group when the amino acid is α-amino acid, α-carboxy group when the amino acid is β-amino acid, and β-amino acid). A β-carboxy group.) Is a derivative converted to a primary amide (-CONH ₂ ). The primary amide may be obtained, for example, by reacting an ester of a compound represented by the general formula (7) (for example, methyl ester, ethyl ester, etc.) with ammonia (ammonolesis), and the primary amide of an amino acid. Alternatively, a substituent on the nitrogen atom of the amino group of the primary amide of the N-alkyl amino acid (α-amino group when the amino acid is α-amino acid, β-amino group when the amino acid is β-amino acid). it may be obtained by introducing the R ^13.

The secondary amide of the compound represented by the general formula (7) is a carboxy group in the general formula (7) (α-carboxy group when the amino acid is α-amino acid, α-carboxy group when the amino acid is β-amino acid, and β-amino acid). A β-carboxy group.) Is a derivative converted to a secondary amide (-CONHR ¹⁷ ). R ¹⁷ is preferably a straight chain or branched chain alkyl group having 1 to 4 carbon atoms. The secondary amide may be obtained, for example, by a condensation reaction of a compound represented by the general formula (7) with a primary amine, and may be obtained from a secondary amide of an amino acid or a secondary amide of an N-alkyl amino acid. amino groups (when the amino acids are α- amino acid α- amino groups, in the case of β- amino acid β- amino group.) may be obtained by introducing a substituent R ¹³ on the nitrogen atom of the ..
As the amide derivative of the compound represented by the general formula (7), a primary amide is preferable.

The polyhydric alcohol ester of the compound represented by the general formula (7) is a carboxy group in the general formula (7) (α-carboxy group when the amino acid is α-amino acid, α-carboxy group when the amino acid is β-amino acid, and β-amino acid). The β-carboxy group.) Is a derivative in which an ester is formed with a polyhydric alcohol. The polyhydric alcohol ester can be obtained, for example, by a condensation reaction between the compound represented by the general formula (7) and the polyhydric alcohol.
Examples of polyhydric alcohols that form an ester with a carboxy group include ethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1 , 5-Pentanediol, Neopentyl glycol, Isoprene glycol (3-methyl-1,3-Butandiol), 1,2-Hexanediol, 1,6-Hexanediol, 3-Methyl-1,5-Pentanediol, 2,2-diethyl-1,3-propanediol (3,3-dimethylolpentane), 1,2-octanediol, 1,8-octanediol, 2-ethyl-1,3-hexanediol, 2,2 , 4-trimethyl-1,3-pentanediol, 1,9-nonanediol, 2-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptan), 2-methyl-1,8 -Octanediol, 1,10-decanediol, 1,12-dodecanediol, isosorbide, catechol, resorcin, hydroquinone, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,4 -Divalent alcohols such as cyclohexanedimethanol, bisphenol A, bisphenol F, hydride bisphenol A, hydride bisphenol F, dimerdiol, diethylene glycol, dipropylene glycol, triethylene glycol; glycerin, trimethylolmethane, 1, 2, 3 -Butantriol, 1,2,4-butanetriol, 2-methyl-1,2,3-propanetriol, 1,2,3-pentantriol, 1,2,4-pentantriol, 1,2,5- Pentantriol, 1,3,5-pentantriol, 2,3,4-pentantriol, 3-methyl-1,2,3-butanetriol, trimethylolethane, 1,2,3-hexanetriol, 1,2 , 6-Hexanetriol, 1,3,6-hexanetriol, 2,3,4-hexanetriol, 2-ethyl-1,2,3-butanetriol, trimethylpropane, 4-propyl-3,4,5 -Trivalent alcohols such as heptanetriol, pentamethylglycerin (2,4-dimethyl-2,3,4-pentantriol); pentaerythritol, erythritol, 1,2,3,4-pentantetrol, 1,2, 4,5-Pentantetrol, 1,3 , 4,5-hexanetetrol, 1,2,5,6-hexanetetrol, 2,3,4,5-hexanetetrol, diglycerin, sorbitan and other tetrahydric alcohols; adonitol, arabitol, xylitol, allose , Tarose, triglycerin and other pentahydric alcohols; dipentaerythritol, sorbitol, mannitol, iditol, inositol, darsitol and other hexahydric alcohols; polyglycerin; and dehydration condensates thereof; and mixtures thereof. ..

The content of the component (C) in the lubricating oil composition is preferably 0.10 to 0.40% by mass, more preferably 0.15 to 0.30% by mass, based on the total amount of the lubricating oil composition. In one embodiment, it is 0.18 to 0.25% by mass. When the content of the component (C) is at least the above lower limit value, the coefficient of friction between metals under low surface pressure conditions can be further reduced. Further, when the content of the component (C) is not more than the above upper limit value, the coefficient of friction between metals under high surface pressure condition can be further increased.

<(D) Succinimide-based ashless dispersant>
In one preferred embodiment, the lubricating oil composition may further comprise (D) an imide succinimide-based ashless dispersant (hereinafter sometimes referred to as "component (D)"). As the component (D), one kind of dispersant may be used alone, or two or more kinds of dispersants may be used in combination. As the component (D), a boborated succinimide-based ashless dispersant may be used, a non-borated succinimide succinimide-based ashless dispersant may be used, or both may be used in combination.

As the component (D), for example, succinimide having at least one alkyl group or alkenyl group in the molecule or a derivative thereof can be used. Examples of the succinimide having at least one alkyl group or alkenyl group in the molecule include a compound represented by the following general formula (8) or (9).

In the general formula (8), R ¹⁸ represents an alkyl group or an alkenyl group having 40 to 400 carbon atoms, and e represents an integer of 1 to 5, preferably 2 to 4. The number of carbon atoms in R ¹⁸ is preferably 60 to 350.

In the general formula (9), R ¹⁹ and R ²⁰ each independently represent an alkyl group or an alkenyl group having 40 to 400 carbon atoms, and may be a combination of different groups. R ¹⁹ and R ²⁰ are particularly preferably polybutenyl groups. Further, f represents an integer of 0 to 4, preferably 1 to 4, and more preferably 1 to 3. The carbon number of R ¹⁹ and R ²⁰ is preferably 60 to 350.

When the carbon number of R ^{18 to} R ²⁰ in the general formulas (8) and (9) is at least the above lower limit value, good solubility in the lubricating oil base oil can be obtained. On the other hand, when the number of carbon atoms of R ^{18 to} R ²⁰ is not more than the above upper limit value, the low temperature fluidity of the lubricating oil composition can be enhanced.

The alkyl group or alkenyl group (R ^{18 to} R ²⁰ ) in the general formulas (8) and (9) may be linear or branched, and is preferably an oligomer of an olefin such as propylene, 1-butene, or isobutene. Examples thereof include branched alkyl groups and branched alkenyl groups derived from co-oligomers of ethylene and propylene. Of these, a branched alkyl group or alkenyl group commonly derived from an oligomer of isobutene commonly called polyisobutylene, or a polybutenyl group is most preferable.
The preferred number average molecular weight of the alkyl or alkenyl groups (R ^{18 to} R ²⁰ ) in the general formulas (8) and (9) is 800 to 3500, more preferably 1000 to 3500.

A so-called monotype succinimide represented by the general formula (8), in which succinic anhydride is added to only one end of the polyamine chain to the succinimide having at least one alkyl group or alkenyl group in the molecule. Includes imides and so-called bis-type succinimides represented by the general formula (9), in which succinic anhydride is added to both ends of the polyamine chain. The lubricating oil composition may contain either a monotype succinimide or a bis-type succinimide, and both of them may be contained as a mixture. The content of the bis-type succinimide or a derivative thereof in the component (D) is preferably 50% by mass or more, more preferably 70% by mass or more, based on the total amount of the component (D) (100% by mass). ..

The method for producing an imide succinate having at least one alkyl group or alkenyl group in the molecule is not particularly limited, and for example, an alkyl or alkenyl succinic acid having an alkyl group or an alkenyl group having 40 to 400 carbon atoms or an alkenyl succinic acid thereof. It can be obtained as a condensation reaction product by reacting the anhydride with the polyamine. As the component (D), the condensation product may be used as it is, or the condensation product may be converted into a derivative described later and used. The condensation product of alkyl or alkenyl succinic acid or its anhydride and polyamine may be a bis-type succinimide (see general formula (9)) in which both ends of the polyamine chain are imidized. It may be a monotype succinimide (see general formula (8)) in which only one end of the polyamine chain is imidized, or a mixture thereof. Here, examples of the polyamine include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine, and a mixture thereof, and a polyamine raw material containing at least one selected from these is preferable. Can be used. The polyamine raw material may or may not further contain ethylenediamine, but from the viewpoint of enhancing the performance of the condensation product or its derivative as a dispersant, the content of ethylenediamine in the polyamine raw material is the total amount of polyamine. By reference, it is preferably 0 to 10% by mass, more preferably 0 to 5% by mass. The succinimide obtained as a condensation reaction product of an alkyl or alkenyl succinic acid having an alkyl or alkenyl group having 40 to 400 carbon atoms or an anhydride thereof and a mixture of two or more kinds of polyamines has a general formula (8). Or a mixture of compounds having different e or f in (9).

Examples of the derivative of the succinate imide include (i) the above-mentioned succinate imide, a monocarboxylic acid having 1 to 30 carbon atoms such as a fatty acid, and a polycarboxylic acid having 2 to 30 carbon atoms (for example, oxalic acid, phthalic acid, etc.). Trimellitic acid, pyromellitic acid, etc.), these anhydrides or ester compounds, alkylene oxides having 2 to 6 carbon atoms, or hydroxy (poly) oxyalkylene carbonates, and the remaining amino groups and / or Modified compounds with oxygen-containing organic compounds in which some or all of the imino groups are neutralized or amidated; (ii) Remaining amino groups and / or iminos by allowing boric acid to act on the above-mentioned succinate imide. Boron-modified compounds (borinated succinate imide) in which some or all of the groups are neutralized or amidated; (iii) The remaining amino groups and / by allowing phosphoric acid to act on the succinate imide described above. Alternatively, a phosphate-modified compound in which some or all of the imino groups are neutralized or amidated; (iv) a sulfur-modified compound obtained by allowing a sulfur compound to act on the above-mentioned succinate imide; and (v). ) Examples thereof include modified compounds obtained by subjecting the above-mentioned succinate imide to a combination of two or more modifications selected from modification with an oxygen-containing organic compound, boron modification, phosphoric acid modification, and sulfur modification. Among these derivatives (i) to (v), a boron-modified compound (borated succinimide) can be preferably used.

The weight average molecular weight of the succinimide-based ashless dispersant (D) is preferably 1000 to 20000, more preferably 1000 to 15000, and particularly preferably 2000 to 9000. When the weight average molecular weight of the component (D) is within the above range, the clutch characteristics and sludge dispersibility can be improved.

When the lubricating oil composition contains the component (D), the content thereof is preferably 0.5 to 8.0% by mass, more preferably 1.0 to 6.0% by mass based on the total amount of the lubricating oil composition. %, More preferably 2.0 to 5.0% by mass. When the content of the component (D) is equal to or higher than the above lower limit, the coefficient of friction between metals under low surface pressure conditions can be further reduced, and the coefficient of friction between metals under medium surface pressure conditions can be further increased, and the clutch. It is possible to improve the characteristics. Further, when the content of the component (D) is not more than the above upper limit value, it becomes possible to further reduce the coefficient of friction between metals under low surface pressure conditions and to improve the clutch characteristics.

When the lubricating oil composition contains the component (D), the content as the nitrogen content is preferably 0.01 to 0.20% by mass, more preferably 0.02 to 0.02 to the total amount of the lubricating oil composition. It is 0.15% by mass, more preferably 0.03 to 0.10% by mass. When the content of the component (D) as the amount of nitrogen is equal to or higher than the above lower limit, the coefficient of friction between metals under low surface pressure conditions is further reduced, and the coefficient of friction between metals under medium surface pressure conditions is further increased. It is possible to improve the clutch characteristics. Further, when the content of the component (D) as the amount of nitrogen is not more than the above upper limit value, it becomes possible to further reduce the coefficient of friction between metals under low surface pressure conditions and to improve the clutch characteristics. ..

When the lubricating oil composition contains a borated succinimide ashless dispersant as the component (D), the content of the component (D) as the amount of boron is preferably 0.001 to 0.001 based on the total amount of the lubricating oil composition. It is 0.05% by mass, more preferably 0.002 to 0.03% by mass, still more preferably 0.003 to 0.02% by mass. When the content of the component (D) as the amount of boron is equal to or higher than the above lower limit, the wear resistance, the transmission torque capacity of the wet clutch, and the coefficient of friction between metals under low surface pressure conditions are further reduced, and the inner surface is further reduced. It is possible to further increase the coefficient of friction between metals under pressure conditions. Further, when the content of the component (D) as the amount of boron is not more than the above upper limit value, it becomes possible to improve the wear resistance and the seizure resistance.

<(E) Antioxidant>
In one preferred embodiment, the lubricating oil composition may further comprise (E) an antioxidant (hereinafter sometimes referred to as "component (E)"). As the component (E), one kind of compound may be used alone, or two or more kinds of compounds may be used in combination. As the component (E), known antioxidants such as amine-based antioxidants and phenol-based antioxidants can be used without particular limitation.

Examples of amine-based antioxidants include aromatic amine-based antioxidants and hindered amine-based antioxidants. Examples of aromatic amine-based antioxidants include primary aromatic amine compounds such as alkylated α-naphthylamine; and alkylated diphenylamine, phenyl-α-naphthylamine, alkylated phenyl-α-naphthylamine, and phenyl-β. -Secondary aromatic amine compounds such as naphthylamine; can be mentioned. As the aromatic amine-based antioxidant, alkylated diphenylamine, alkylated phenyl-α-naphthylamine, or a combination thereof can be preferably used.

Examples of hindered amine-based antioxidants include 2,2,6,6-tetraalkylpiperidine derivatives. As the 2,2,6,6-tetraalkylpiperidine derivative, a 2,2,6,6-tetraalkylpiperidine derivative having a substituent at the 4-position is preferable. Further, two 2,2,6,6-tetraalkylpiperidine skeletons may be bonded via their respective 4-position substituents. Further, the N-position of the 2,2,6,6-tetraalkylpiperidine skeleton may be unsubstituted, and the N-position may be substituted with an alkyl group having 1 to 4 carbon atoms. The 2,2,6,6-tetraalkylpiperidine skeleton is preferably a 2,2,6,6-tetramethylpiperidine skeleton.

As the substituent at the 4-position of the 2,2,6,6-tetraalkylpiperidine skeleton, an asyloxy group (R ²¹ COO-), an alkoxy group (R ²¹ O-), an alkylamino group (R ²¹ NH-), Acylamino group (R ²¹ CONH-), etc. can be mentioned. R ²¹ is preferably a hydrocarbon group having 1 to 30 carbon atoms, more preferably 1 to 24 carbon atoms, and even more preferably 1 to 20 carbon atoms. Examples of the hydrocarbon group include an alkyl group, an alkenyl group, a cycloalkyl group, an alkylcycloalkyl group, an aryl group, an alkylaryl group, an arylalkyl group and the like.

When two 2,2,6,6-tetraalkylpiperidine skeletons are bonded via their respective 4-position substituents, the substituent is a hydrocarbylenebis (carbonyloxy) group (-OOC-). R ²² -COO-), hydrocarbylene diamino group (-HN-R ²² -NH-), hydrocarbylenebis (carbonylamino) group (-HNCO-R ²² -CONH-), and the like. R ²² is preferably a hydrocarbylene group having 1 to 30 carbon atoms, and more preferably an alkylene group.

As the substituent at the 4-position of the 2,2,6,6-tetraalkylpiperidine skeleton, an asyloxy group is preferable. An example of a compound having an asyloxy group at the 4-position of the 2,2,6,6-tetraalkylpiperidine skeleton is an ester of 2,2,6,6-tetramethyl-4-piperidinol and a carboxylic acid. Can be done. Examples of the carboxylic acid include straight-chain or branched-chain aliphatic carboxylic acids having 8 to 20 carbon atoms.

Examples of phenolic antioxidants are 4,4'-methylenebis (2,6-di-tert-butylphenol); 4,4'-bis (2,6-di-tert-butylphenol); 4,4'. -Bis (2-methyl-6-tert-butylphenol); 2,2'-methylenebis (4-ethyl-6-tert-butylphenol); 2,2'-methylenebis (4-methyl-6-tert-butylphenol); 4,4'-butylidenebis (3-methyl-6-tert-butylphenol); 4,4'-isopropyridenebis (2,6-di-tert-butylphenol); 2,2'-methylenebis (4-methyl-6) -Nonylphenol); 2,2'-isobutylidenebis (4,6-dimethylphenol); 2,2'-methylenebis (4-methyl-6-cyclohexylphenol); 2,6-di-tert-butyl-4 -Methylphenol; 2,6-di-tert-butyl-4-ethylphenol; 2,4-dimethyl-6-tert-butylphenol; 2,6-di-tert-butyl-4- (N, N'-dimethyl) Aminomethyl) phenol; 4,4'-thiobis (2-methyl-6-tert-butylphenol); 4,4'-thiobis (3-methyl-6-tert-butylphenol); 2,2'-thiobis (4-) Methyl-6-tert-butylphenol); bis (3-methyl-4-hydroxy-5-tert-butylbenzyl) sulfide; bis (3,5-di-tert-butyl-4-hydroxybenzyl) sulfide; 2,2 '-Thio-diethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate]; tridecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate; Pentaerythritol-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate]; octyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate; octadecyl- 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate; 3-methyl-5-tert-butyl-4-hydroxyphenol fatty acid esters and the like can be mentioned.

When the lubricating oil composition contains an amine-based antioxidant as the component (E), the content thereof is preferably 0.01 to 5% by mass, more preferably 0.02 to 2% by mass based on the total amount of the lubricating oil composition. It is 3% by mass. When the content of the amine-based antioxidant is equal to or higher than the above lower limit, the oxidation stability is enhanced, the friction coefficient between metals under low surface pressure conditions is further reduced, and the friction coefficient between metals under medium surface pressure conditions is further reduced. Can be further enhanced. Further, when the content of the amine-based antioxidant is not more than the above upper limit value, it is possible to enhance the oxidative stability.

When the lubricating oil composition contains a phenolic antioxidant as the component (E), the content thereof is preferably 0.01 to 5% by mass, more preferably 0.02 to 2% by mass based on the total amount of the lubricating oil composition. It is 3% by mass. When the content of the phenolic antioxidant is equal to or higher than the above lower limit, the oxidation stability is enhanced, the friction coefficient between metals under low surface pressure conditions is further reduced, and the friction coefficient between metals under medium surface pressure conditions is further reduced. Can be further enhanced. Further, when the content of the phenolic antioxidant is not more than the above upper limit value, it is possible to enhance the oxidative stability.

<(F) Thiadiazole compound>
In one preferred embodiment, the lubricating oil composition may further comprise one or more thiadiazole compounds (hereinafter sometimes referred to as "component (F)"). As the component (F), one kind of compound may be used alone, or two or more kinds of compounds may be used in combination.

Examples of the component (F) include 1,3,4-thiadiazole represented by the following general formula (10), 1,2,4-thiadiazole compound represented by the following general formula (11), and the following general formula. Examples thereof include 1,2,3-thiadiazole compounds represented by (12).

（一般式（１０）〜（１２）中、Ｒ^２３及びＲ^２４は同一でも異なっていてもよく、それぞれ独立に水素又は炭素数１〜２０のヒドロカルビル基を表し；ｇ及びｈは同一でも異なっていてもよく、それぞれ独立に０〜８の整数を表す。）

(In the general formulas (10) to (12), R ²³ and R ²⁴ may be the same or different, and independently represent hydrogen or a hydrocarbyl group having 1 to 20 carbon atoms; g and h are the same or different. It may represent an integer from 0 to 8 independently.)

Among the thiadiazole compounds, a thiadiazole compound represented by any of the general formulas (10) to (12) and having a hydrocarbyl dithio group can be particularly preferably used.

The content of the component (F) in the lubricating oil composition is preferably 0.005 to 1% by mass, more preferably 0.01 to 0.50% by mass, based on the total amount of the lubricating oil composition. When the content of the component (F) is at least the above lower limit, it is possible to improve seizure resistance, wear resistance, and fatigue resistance, and further reduce the coefficient of friction between metals under low surface pressure conditions. However, it becomes possible to further increase the coefficient of friction between metals under medium surface pressure conditions. Further, when the content of the component (F) is not more than the above upper limit value, the seizure resistance and the fatigue resistance can be improved.

<Other additives>
In one embodiment, the lubricating oil composition comprises a viscosity index improver, a pour point lowering agent, an antiwear or extreme pressure agent other than component (B), an antiwear additive other than component (C), and component (F). It may further contain one or more selected from corrosion inhibitors other than, rust preventives, metal inactivating agents other than the component (F), seal swelling agents, defoaming agents, anti-emulsifiers, and colorants.

As the viscosity index improver, a known viscosity index improver used in a lubricating oil can be used without particular limitation. Examples of viscosity index improvers include polymethacrylate, ethylene-α-olefin copolymer and hydride thereof, copolymer of α-olefin and ester monomer having a polymerizable unsaturated bond, polyisobutylene and its hydride. Examples thereof include hydrides, hydrides of styrene-diene copolymers, styrene-maleic anhydride copolymers, and polyalkylstyrenes. Among these, polymethacrylate, ethylene-α-olefin copolymer or hydride thereof, or a combination thereof can be preferably used. The viscosity index improver may be a dispersed type or a non-dispersed type. In one embodiment, the weight average molecular weight of the viscosity index improver can be, for example, 2000-30000. The lubricating oil composition does not have to contain a viscosity index improver, but when the lubricating oil composition contains a viscosity index improver, the content thereof is usually 1.0 to 15% by mass based on the total amount of the composition. %.

As the pour point lowering agent, for example, a known pour point lowering agent such as a polymethacrylate-based polymer can be used without particular limitation. The lubricating oil composition does not have to contain a pour point lowering agent, but when the lubricating oil composition contains a pour point lowering agent, the content thereof is usually 0.01 to 0, based on the total amount of the composition. It is 5% by mass.

Examples of the wear inhibitor or extreme pressure agent other than the component (B) include sulfur compounds such as disulfides, olefins sulfide, and oils and fats sulfide, and phosphorus-containing wear inhibitors other than the component (B). Examples of the phosphorus-containing anti-wear agent other than the component (B) include phosphoric acid, thiophosphate, dithiophosphate, trithiophosphate, their complete esters, and partial esters thereof. The lubricating oil composition does not have to contain an anti-wear agent other than the component (B), but when the lubricating oil composition contains an anti-wear agent other than the component (B), the content thereof is the total amount of the composition. By standard, it is usually 0.01 to 5% by mass.

As the friction modifier other than the component (C), for example, one or more friction modifiers selected from organic molybdenum compounds and ashless friction modifiers can be used. The lubricating oil composition does not have to contain a friction modifier other than the component (C), but when the lubricating oil composition contains a friction modifier other than the component (C), the content thereof is the total amount of the composition. By standard, it is usually 0.01 to 3% by mass.

Examples of the organic molybdenum compound include a sulfur-containing organic molybdenum compound and a sulfur-free organic molybdenum compound as a constituent element. Examples of sulfur-containing organic molybdenum compounds include molybdenum dithiocarbamate compounds; molybdenum dithiophosphate compounds; molybdenum compounds (for example, molybdenum oxide such as molybdenum dioxide and molybdenum trioxide, orthomolybdenum acid, paramolybdenum acid, and (poly) sulfide. Of molybdenum acid such as molybdenum acid, metal salt of these molybdenum acid, molybdate such as ammonium salt, molybdenum disulfide, molybdenum trisulfide, molybdenum pentasulfide, molybdenum sulfide such as polymolybdenum sulfide, molybdenum sulfide acid, molybdenum sulfide acid Metal salts or amine salts, molybdenum halides such as molybdenum chloride, etc.) and sulfur-containing organic compounds (eg, alkyl (thio) xanthate, thiadiazol, mercaptothiaizole, thiocarbonate, tetrahydrocarbyltiuram disulfide, bis (di (thio) Thio) Hydrocarbyl dithiophosphonate) Disulfide, organic (poly) sulfide, sulfide ester, etc.) or complexes with other organic compounds; and sulfur-containing molybdenum compounds such as molybdenum sulfide and molybdenum sulfide and alkenyl succinic acid. Examples thereof include organic molybdenum compounds containing sulfur, such as a complex with imide. The organic molybdenum compound may be a mononuclear molybdenum compound or a polynuclear molybdenum compound such as a dinuclear molybdenum compound or a trinuclear molybdenum compound. Examples of sulfur-free organic molybdenum compounds as constituent elements include molybdenum-amine complexes, molybdenum-succinateimide complexes, organic acid molybdenum salts, and alcohol molybdenum salts.

Examples of ashless friction modifiers other than the component (C) include compounds such as aliphatic amines, fatty acid amides, aliphatic ureas, fatty acid hydrazides, fatty acid esters, fatty acids, fatty acid metal salts, fatty alcohols, and aliphatic ethers. Can be mentioned. These compounds preferably have a hydrocarbon group having 10 to 30 carbon atoms, more preferably an alkyl or alkenyl group having 10 to 30 carbon atoms, and even more preferably a linear alkyl or alkenyl group having 12 to 24 carbon atoms.

As the corrosion inhibitor other than the component (F), for example, known corrosion inhibitors such as benzotriazole-based, tolyltriazole-based, and imidazole-based compounds can be used. The lubricating oil composition does not have to contain a corrosion inhibitor other than the component (F), but when the lubricating oil composition contains a corrosion inhibitor other than the component (F), the content thereof is the lubricating oil composition. It is usually 0.005 to 5% by mass based on the total amount of the material.

As the rust preventive, known rust preventives such as petroleum sulfonate, alkylbenzene sulfonate, dinonylnaphthalene sulfonate, alkenyl succinate ester, and polyhydric alcohol ester can be used. The lubricating oil composition does not have to contain a rust preventive, but when the lubricating oil composition contains a rust preventive, the content thereof is usually 0.005 to 5 mass based on the total amount of the lubricating oil composition. %.

Examples of the metal inactivating agent other than the component (F) include imidazoline, a pyrimidine derivative, mercaptobenzothiazole, benzotriazole and its derivative, 2- (alkyldithio) benzimidazole, and β- (o-carboxybenzylthio). A known metal inactivating agent such as propionnitrile can be used. The lubricating oil composition does not have to contain a metal inactivating agent other than the component (F), but when the lubricating oil composition contains a metal inactivating agent other than the component (F), the content thereof is The total amount of the lubricating oil composition is usually 0.005 to 5% by mass.

As the seal swelling agent, for example, a known seal swelling agent such as alcohol, alkylbenzene, substituted sulfolane, or mineral oil that causes swelling of the elastomer material can be used.
The alcohol-based seal swelling agent is a low-volatile linear alkyl alcohol, and preferred examples thereof include decyl alcohol, tridecyl alcohol, and tetradecyl alcohol.
Examples of alkylbenzene that can be used as a seal swelling agent include dodecylbenzene, tetradecylbenzene, dinonylbenzene, di (2-ethylhexyl) benzene and the like.
Examples of the substituted sulfolane that can be used as the seal swelling agent include a substituted sulfolane compound represented by the following general formula (13).

一般式（１３）中、Ｒ^２５は炭素数４以上の炭化水素基であり、好ましくは炭素数４〜２５、より好ましくは炭素数４〜１０のアルキル又はアルケニル基である。Ｒ^２６及びＲ^２７はそれぞれ水素原子または炭素数７以下の（好ましくは直鎖の）アルキル基であり、好ましくはＲ^２６及びＲ^２７の一方が水素原子、他方（好ましくはＲ^２７）が水素原子またはメチル基であり、より好ましくはＲ^２６及びＲ^２７の両方が水素原子である。Ｘ^５は酸素原子または硫黄原子であり、好ましくは酸素原子である。
シール膨潤剤として用いることのできる鉱油は典型的には、ナフテン分または芳香族分の含有量の高い低粘度鉱油である。
潤滑油組成物はシール膨潤剤を含有してもよく、含有しなくてもよいが、潤滑油組成物がシール膨潤剤を含有する場合、その含有量は、組成物全量基準で、通常０．０１〜３．０質量％である。

In the general formula (13), R ²⁵ is a hydrocarbon group having 4 or more carbon atoms, preferably an alkyl or alkenyl group having 4 to 25 carbon atoms, and more preferably 4 to 10 carbon atoms. R ²⁶ and R ²⁷ are hydrogen atoms or alkyl groups having 7 or less carbon atoms (preferably linear), respectively, preferably one of R ²⁶ and R ²⁷ is a hydrogen atom and the other (preferably R ²⁷ ) is a hydrogen atom. Alternatively, it is a methyl group, more preferably both R ²⁶ and R ²⁷ are hydrogen atoms. X ⁵ is an oxygen atom or a sulfur atom, preferably an oxygen atom.
Mineral oils that can be used as seal swelling agents are typically low viscosity mineral oils with high naphthenic or aromatic content.
The lubricating oil composition may or may not contain a seal swelling agent, but when the lubricating oil composition contains a seal swelling agent, the content thereof is usually 0, based on the total amount of the composition. It is 01 to 3.0% by mass.

As the defoaming agent, for example, known defoaming agents such as silicone, fluorosilicone, and fluoroalkyl ether can be used. When the lubricating oil composition contains an antifoaming agent, the content thereof is usually 0.0005 to 0.01% by mass based on the total amount of the lubricating oil composition.

As the anti-emulsifier, a known anti-emulsifier such as a polyalkylene glycol-based nonionic surfactant can be used. When the lubricating oil composition contains an anti-emulsifier, the content thereof is usually 0.005 to 5% by mass based on the total amount of the lubricating oil composition.

As the colorant, a known colorant such as an azo compound can be used.

<Lubricating oil composition>
The kinematic viscosity of the lubricating oil composition at 40 ° C. is preferably 12 to 40 mm ² / s, more preferably 14 to 30 mm ² / s, and even more preferably 16 to 25 mm ² / s. When the kinematic viscosity of the lubricating oil composition at 40 ° C. is not more than the above upper limit value, it is possible to improve fuel efficiency. Further, when the kinematic viscosity of the lubricating oil composition at 40 ° C. is at least the above lower limit value, it is possible to sufficiently form an oil film at the lubricated portion and improve the wear resistance.

Kinematic viscosity at 100 ° C. of the lubricating oil composition is preferably 2-12 mm ² / s, more preferably 3 to 8 mm ² / s, more preferably 4 to 6 mm ² / s. When the kinematic viscosity of the lubricating oil composition at 100 ° C. is equal to or higher than the above lower limit value, it is possible to sufficiently form an oil film at the lubricated portion and enhance wear resistance. Further, when the kinematic viscosity of the lubricating oil composition at 100 ° C. is not more than the above upper limit value, it is possible to improve fuel efficiency.

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples. However, the present invention is not limited to these examples.

<Examples 1 to 13 and Comparative Examples 1 to 11>
As shown in Tables 1 to 5, the lubricating oil composition of the present invention (Examples 1 to 13) and the lubricating oil composition for comparison (Comparative Examples 1 to 11) were prepared, respectively. In the table, the content of each component is based on the total amount of the lubricating oil composition (100% by mass). The details of the ingredients are as follows.

(Lubricating oil base oil)
O-1: Hydrorefined mineral oil (API group III base oil, kinematic viscosity (40 ° C): 19.42 mm ² / s, kinematic viscosity (100 ° C): 4.234 mm ² / s, viscosity index: 125, pour point _{: -17.5 ℃,% C P:} 79.4,% C N: 20.6, sulfur content: less than 10 mass ppm)

((A) Calcium-based cleaning agent)
A-1: Calcium sulfonate detergent, base value 300 mgKOH / g, Ca: 11.6% by mass
A-2: Calcium salicylate detergent, base value 225 mgKOH / g, Ca: 8.0% by mass
A-3 ^* : Calcium sulfonate detergent, base value 85 mgKOH / g, Ca: 4.8% by mass

((B) Phosphite ester anti-wear agent)
B-1: Bis (3-thiaundesyl) hydrogen phosphite, P: 7.3% by mass
B-2: Dibutylhydrogenphosphite, P: 15.9% by mass

((C) Ash-free friction modifier)
C-1: N-oleoyl-N-methylglycin C-2 ^* : Gglycerol monooleate C-3 ^* : Oleylamine-ethylene oxide adduct C-4 ^* : Succinimide-based friction modifier (alkenyl succinic anhydride) Condensation product of product and polyamine, carbon number of alkenyl group: 18, N: 5.5% by mass)
C-5 ^* : Polyamine-based friction modifier (condensation product of tetraethylenepentamine and isostearic acid)

((D) Succinimide-based ashless dispersant)
D-1: Borylated polybutenyl succinimide, weight average molecular weight: 5000, number average molecular weight of polybutenyl groups: 1000, B: 0.3% by mass, N: 1.3% by mass
D-2: Non-borated polybutenyl succinimide, weight average molecular weight: 4500, number average molecular weight of polybutenyl groups: 1000, N: 1.3% by mass

((E) Antioxidant)
E-1: Amine-based antioxidant E-2: Phenolic antioxidant

((F) Thiadiazole compound)
F-1: Thiadiazole compound having a hydrocarbyl dithio group represented by the general formulas (10) to (12), S: 36% by mass.

((G) Other additives)
Seal swelling agent: substituted sulfolane compound represented by the general formula (13), X ⁵ = oxygen atom, molecular weight: 278.45, S: 11.5% by mass

(Pin-on disk test)
For each of the lubricating oil compositions, a pin-on disc tester was used to measure the coefficient of friction between the disc and the pin immersed in the sample oil. The measurement conditions are as follows.
Pin: Material JIS SUJ-2, diameter 6 mm
Disc: Material JIS SUJ-2, diameter 32 mm
Load: 200N
Surface pressure: 5.3 MPa
Slip speed: 0.2m / s
Oil supply method: Oil bath supply Oil temperature: 80 ° C
Test time: 30 minutes The results are shown in Tables 1-5. The lower the coefficient of friction between metals measured in this test, the lower the coefficient of friction between metals under low surface pressure conditions, which is preferable.

(LFW-1 test)
For each of the lubricating oil compositions, a block-on-ring friction and wear test was conducted in accordance with JASO M358-2005 (coefficient of friction characteristic test of belt-type CVT oil) except that the load was changed to 1100 N and the surface pressure was changed to 0.6 GPa. The coefficient of friction between metals (coefficient of dynamic friction) was measured by a machine (LFW-1). The test conditions were block: H60, ring: S10, load: 1100 N, surface pressure: 0.6 GPa, oil temperature 80 ° C., and the coefficient of friction between metals was measured at a slip speed of 0.1 m / s. The results are shown in Tables 1-5. The higher the coefficient of friction between metals measured in this test, the higher (larger) the coefficient of friction between metals (transmission torque capacity of the metal belt) under medium surface pressure conditions, which is preferable.

(Evaluation results)
The lubricating oil compositions of Examples 1 to 13 showed good results in both the coefficient of friction between metals under medium surface pressure conditions and the coefficient of friction between metals under low surface pressure conditions.
The lubricating oil composition of Comparative Example 1 containing a calcium-based cleaning agent outside the range of the component (A) instead of the component (A) was subjected to lower surface pressure conditions as compared with the lubricating oil composition of Example 1. The results were inferior in the coefficient of friction between metals.
The lubricating oil composition of Comparative Example 2 containing no component (C) showed inferior results in the coefficient of friction between metals under low surface pressure conditions as compared with the lubricating oil composition of Example 1.
The lubricating oil composition of Comparative Example 3 containing an ashless friction modifier outside the range of the component (C) instead of the component (C) has a lower surface pressure condition than the lubricating oil composition of Example 1. Inferior results were shown in both the coefficient of friction between metals below and the coefficient of friction between metals under medium surface pressure conditions.
The lubricating oil composition of Comparative Example 4 containing a calcium-based cleaning agent outside the range of the component (A) instead of the component (A) was compared with the lubricating oil composition of Example 2 under medium surface pressure conditions. The results were inferior in the coefficient of friction between metals.
The lubricating oil composition of Comparative Example 5 containing no component (C) showed inferior results in the coefficient of friction between metals under low surface pressure conditions as compared with the lubricating oil composition of Example 2.
The lubricating oil composition of Comparative Example 6 containing no component (C) showed inferior results in the coefficient of friction between metals under low surface pressure conditions as compared with the lubricating oil composition of Example 7.
The lubricating oil composition of Comparative Example 7 containing an ashless friction modifier other than the component (C) instead of the component (C) was compared with the lubricating oil composition of Example 7 under low surface pressure conditions. The result was inferior in the coefficient of friction between metals.
The lubricating oil composition of Comparative Example 8 containing an ashless friction modifier other than the component (C) instead of the component (C) was compared with the lubricating oil composition of Example 7 under low surface pressure conditions. The results were inferior in both the coefficient of friction between metals and the coefficient of friction between metals under medium surface pressure conditions.
The lubricating oil composition of Comparative Example 9 containing an ashless friction modifier other than the component (C) instead of the component (C) was compared with the lubricating oil composition of Example 8 under low surface pressure conditions. The result was inferior in the coefficient of friction between metals.
The lubricating oil composition of Comparative Example 10 containing a plurality of ashless friction modifiers other than the component (C) instead of the component (C) has a lower surface pressure condition than the lubricating oil composition of Example 8. Inferior results were shown in the coefficient of friction between metals below.
The lubricating oil composition of Comparative Example 11 containing a plurality of ashless friction modifiers other than the component (C) instead of the component (C) had medium surface pressure conditions as compared with the lubricating oil composition of Example 8. Inferior results were shown in the coefficient of friction between metals below.

Claims (3)

Lubricating oil base oil and
(A) A calcium-based cleaning agent having a base value of more than 100 mgKOH / g,
(B) Phosphite ester-based anti-wear agent,
(C) A lubricating oil composition, which comprises an amino acid having an alkyl or alkenyl having 6 to 24 carbon atoms or an acyl group and / or a derivative thereof. The lubricating oil composition according to claim 1, wherein the component (A) is a calcium sulfonate cleaning agent having a base value of more than 100 mgKOH / g. The lubricating oil composition according to claim 1 or 2, which is a lubricating oil composition for a continuously variable transmission.