JP2001279286A - Lubricant oil composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a lubricant oil composition for transmission gears that has excellent increasing effect on both of dynamic and static friction coefficients, particularly of a wet clutch. SOLUTION: The objective lubricant composition is obtained characteristically by formulating (A)>=0.035 mass % of a boron-containing, ash-free dispersant calculated as boron on the basis of the whole amount of the composition and (B)>=0.01 mass % of an alkaline earth metal sulfonate with the whole base value of 50-500 mg KOH/g calculated as an alkaline earth metal on the basis of whole amount of the composition, to a lubricant base oil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating oil composition, and more particularly to a lubricating oil composition which is effective for increasing the friction coefficient of a wet clutch and is particularly suitable for an automatic transmission or a continuously variable transmission. .

[0002]

2. Description of the Related Art An automatic transmission is composed of a torque converter, a wet clutch, a gear bearing mechanism and a hydraulic control mechanism for controlling these, and the speed ratio is determined by the number of teeth of meshed gears. The automatic transmission has several types of gear mechanisms, and a gear for determining a gear ratio is appropriately selected in accordance with a vehicle speed and a load to obtain a desired gear ratio. An automatic transmission has a large number of wet clutches, and when one is engaged and the other is idle, a gear for determining a gear ratio is selected. When changing the gear ratio, the wet clutch that had been engaged until then is released and another wet clutch is engaged, so that the dynamic friction coefficient of the wet clutch is sufficient to realize quick shifting. Need to be high. In order to transmit the engine torque, the engaged wet clutch must not slip until it is released, and the coefficient of static friction must be sufficiently high. These friction coefficients are strongly affected by the performance of the lubricating oil used together with the material of the clutch.

[0003] In the design of an automatic transmission, the size, the number, and the pressing oil pressure of the wet clutch are determined according to the output of the engine to be combined. If the friction coefficient of the wet clutch is low, it is necessary to increase the clutch size, increase the number of clutches, or increase the pressing hydraulic pressure. An increase in the clutch size and the number of clutches increase the size of the automatic transmission, and an increase in the pressing oil pressure imposes an excessive load on a hydraulic pump incorporated in the automatic transmission. On the other hand, unlike an automatic transmission, a continuously variable transmission does not use a wet clutch for shifting, but uses a wet clutch for switching between forward and backward travel. In addition, most continuously variable transmissions combined with a torque converter have a built-in lock-up clutch that is effective for improving fuel efficiency. With respect to increasing the friction coefficient of a wet clutch, for example, JP-A-6-240275 discloses a lubricating oil containing an amine compound, an overbased calcium phenate, a succinimide-based ashless dispersant, and a B-shielded succinimide. It has been proposed that the composition is effective in increasing the coefficient of static friction. Also, Japanese Patent Application Laid-Open No. 8-12778
In JP-A-9, a lubricating oil composition containing a bis-type alkenyl succinimide, a mono-type alkenyl succinimide, and a low-molecular weight and high-molecular weight polydimethylsiloxane is effective in improving the dynamic friction coefficient and the static friction coefficient. Although many lubricating oil compositions to which these techniques are applied have been put to practical use, they are still insufficient for fuel efficiency of automobiles, and further improvements have been desired.

[0004]

[0005] Against the background of global environmental problems, there is an urgent need to improve the fuel efficiency of automobiles, mainly for the purpose of reducing carbon dioxide emissions. There is a strong demand for the development of a lubricating oil that is effective in increasing the friction coefficient of a wet clutch in order to reduce the size of the transmission and reduce pump loss. Also in a continuously variable transmission, increasing the friction coefficient of the wet clutch is effective in reducing the size of the transmission and reducing pump loss, and the high friction coefficient of the wet clutch is the same as the lubricating oil used in automatic transmissions. The development of lubricating oils that are effective in the development of fuel oil is eagerly awaited. SUMMARY OF THE INVENTION The present invention meets these requirements, and an object thereof is to provide a lubricating oil composition which is particularly excellent in improving the dynamic friction coefficient and the static friction coefficient of a wet clutch.

[0005]

According to the present invention, a lubricating base oil contains a boron-containing ashless dispersant (hereinafter referred to as "component (A)") in an amount of 0.035% by mass or more based on the total amount of the composition. And a lubricating composition containing an alkaline earth metal sulfonate having a total base number of 50 to 500 mgKOH / g (hereinafter referred to as "component (B)") in an amount of 0.01% by mass or more as an alkaline earth metal based on the total amount of the composition. Oil composition.
The present invention is preferably a lubricant composition comprising the above lubricating oil composition and a phosphorus-based additive (hereinafter referred to as “component (C)”).

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the contents of the present invention will be described in more detail. As the lubricating base oil in the lubricating oil composition of the present invention, any mineral oil and / or synthetic oil used as the base oil of ordinary lubricating oils can be used. As the mineral oil, specifically, for example, a lubricating oil fraction obtained by atmospheric distillation and vacuum distillation of crude oil is subjected to solvent dewatering, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, and hydrogenation. Purification, sulfuric acid washing,
A paraffinic or naphthenic oil or normal paraffin refined by appropriately combining purification treatments such as clay treatment can be used.

[0007] The synthetic oil is not particularly limited,
For example, poly-α-olefins (1-octene oligomer, 1-decene oligomer, ethylene-propylene oligomer, etc.) and hydrides thereof, isobutene oligomers and hydrides thereof, isoparaffin, alkylbenzene,
Alkyl naphthalene, diester (ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, di-2-ethylhexyl sebacate, etc.), polyol ester (trimethylolpropane caprylate, trimethylolpropaneperalgonate, pentaerythritol 2) -Ethylhexanoate, pentaerythritol pelargonate), polyoxyalkylene glycol, dialkyldiphenyl ether, polyphenyl ether and the like.

[0008] The kinematic viscosity of these lubricating base oils is not particularly limited, and is arbitrary. Usually, the kinematic viscosity at 100 ° C is preferably 1 to 10 mm ² / s, more preferably ^{2 to} 8 mm ² / s.
/ S.

The component (A) in the lubricating oil composition of the present invention is an ashless dispersant containing boron. The component (A)
It is important to contain boron. When an ashless dispersant containing no boron is used as the component (A), the effect of increasing the friction coefficient of the wet clutch is poor, which is not preferable. The boron content in the component (A) is arbitrary, but the lower limit of the content is preferably from the viewpoint that the effect of improving the friction coefficient of the wet clutch, and the effects excellent in wear resistance and oxidation stability are obtained. The content is 0.2% by mass, more preferably 0.4% by mass, while the upper limit of the content is preferably 4% by mass, more preferably 2.5% by mass.

As the component (A), a nitrogen-containing compound having at least one alkyl group or alkenyl group in the molecule or a derivative thereof modified with a boron compound can be mentioned. This alkyl group or alkenyl group may be linear or branched, but is preferably, for example, olefin, oligomer such as propylene, 1-butene, isobutylene or co-oligomer of ethylene and propylene. Derived branched alkyl groups and branched alkenyl groups are mentioned. This alkyl group or alkenyl group preferably has 40 to 400 carbon atoms, more preferably 6 carbon atoms.
0 to 350. When the number of carbon atoms of the alkyl group or the alkenyl group is less than 40, the solubility of the compound in a lubricating base oil may decrease. On the other hand, when the number of carbon atoms of the alkyl group or the alkenyl group exceeds 400, the lubricating oil composition It is not preferable because the low-temperature fluidity of the material may be deteriorated.

Specific examples of the nitrogen-containing compound or a derivative thereof include one or more compounds selected from the following compounds. (A-1) succinimide having at least one alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule, or a derivative thereof (A-2) having an alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule (A-3) a polyamine having at least one alkyl or alkenyl group having 40 to 400 carbon atoms in a molecule, or a derivative thereof

Specific examples of the succinimide (A-1) include compounds represented by the following general formula (1) or (2).

[0013]

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(1) In the formula (1), R ¹ has a carbon number of 40 to 40.
Represents an alkyl group or alkenyl group of 0, preferably 60 to 350, and a represents an integer of 1 to 5, preferably 2 to 4. )

[0015]

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In the formula (2), R ² and R ³ each independently represent an alkyl or alkenyl group having 40 to 400, preferably 60 to 350 carbon atoms, and b is 0 to 4, preferably 1 to 4. 3 represents an integer.)

The succinimide is a so-called mono-type succinimide of the general formula (1) in which succinic anhydride is added to one end of a polyamine to form an imide bond, and succinic anhydride is added to both ends of the polyamine. There is a so-called bis-type succinimide such as the general formula (2) in which an acid is added to form an imide bond, and the component (A-1) includes
Either one or a mixture thereof may be used.

As the benzylamine (A-2), specifically, for example, a compound represented by the general formula (3) can be mentioned.

[0019]

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(3) In the formula (3), R ⁴ has ^{40 to 40} carbon atoms.
Represents an alkyl group or alkenyl group of 0, preferably 60 to 350, and c represents an integer of 1 to 5, preferably 2 to 4. Although the method for producing this benzylamine is not limited at all, for example, a polyolefin such as a propylene oligomer having 40 to 400 carbon atoms, polybutene, and an ethylene-α-olefin copolymer is reacted with phenol to form an alkylphenol. Thereafter, it can be obtained by reacting formaldehyde with a polyamine such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, or pentaethylenehexamine by a Mannich reaction.

As the polyamine (A-3), specifically, for example, a compound represented by the following general formula (4) can be mentioned.

[0022]

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In the formula (4), R ⁵ is a group having 40 to 40 carbon atoms.
Represents an alkyl group or alkenyl group of 0, preferably 60 to 350, and d represents an integer of 1 to 5, preferably 2 to 4. The method for producing this polyamine is not limited at all. For example, after chlorinating a polyolefin such as a propylene oligomer having 40 to 400 carbon atoms, polybutene, and an ethylene-α-olefin copolymer, ammonia, ethylenediamine, diethylenetriamine, It can be obtained by reacting a polyamine such as triethylenetetramine, tetraethylenepentamine and pentaethylenehexamine.

Examples of the derivative of the nitrogen-containing compound include, for example, monocarboxylic acids having 2 to 30 carbon atoms (such as fatty acids), oxalic acid, phthalic acid and trimellitic acid. , Pyromellitic acid, etc.
30 to 30 polycarboxylic acids to neutralize or amidate the remaining amino groups and / or imino groups, or to so-called carboxylic acid-modified compounds or nitrogen-containing compounds as described above. Examples thereof include a sulfur-modified compound reacted with a sulfur compound and a mixture thereof.

The component (A) of the present invention is obtained by modifying the above-mentioned nitrogen-containing compound or a derivative thereof with a boron compound. The method of modifying the nitrogen-containing compound or a derivative thereof with the boron compound is not limited at all, and any method is possible. For example, boric acid, boric acid, A method in which a boron compound such as a salt or a borate ester is allowed to act to neutralize or amidate some or all of the amino group and / or imino group remaining in the nitrogen-containing compound or a derivative thereof. .

Specific examples of the boric acid include orthoboric acid, metaboric acid, tetraboric acid, and the like. Further, specific examples of the borate include alkali metal salts, alkaline earth metal salts, and ammonium salts of boric acid. More specifically, for example, lithium borate such as lithium metaborate, lithium tetraborate, lithium pentaborate, lithium perborate; sodium metaborate, sodium diborate, sodium tetraborate, sodium pentaborate, Sodium hexaborate,
Sodium borate such as sodium octaborate; potassium borate such as potassium metaborate, potassium tetraborate, potassium pentaborate, potassium hexaborate, potassium octaborate; calcium metaborate, calcium diborate, tetraborate Calcium borate such as tricalcium phosphate, pentacalcium tetraborate and calcium hexaborate; magnesium borate such as magnesium metaborate, magnesium diborate, trimagnesium tetraborate, pentamagnesium tetraborate and magnesium hexaborate And ammonium borates such as ammonium metaborate, ammonium tetraborate, ammonium pentaborate and ammonium octaborate.

Examples of the boric acid ester include esters of boric acid and preferably an alkyl alcohol having 1 to 6 carbon atoms. More specifically, for example, monomethyl borate, dimethyl borate, trimethyl borate, Monoethyl borate, diethyl borate, triethyl borate, monopropyl borate, dipropyl borate, tripropyl borate,
Monobutyl borate, dibutyl borate, tributyl borate and the like can be mentioned.

The component (A) of the present invention includes the component (A-
1) Modification of a nitrogen-containing compound represented by (A-2) or (A-3) or a derivative thereof with a boron compound
Species or a mixture of two or more species can be used. Particularly, from the viewpoint of obtaining an excellent effect of improving the friction coefficient of a wet clutch, the succinimide represented by (A-1) or a derivative thereof is converted to a boron compound. It is preferable to use those modified by

In the lubricating oil composition of the present invention, the lower limit of the amount of component (A) is 0.035% by mass, preferably 0.04% by mass, based on the total amount of the lubricating oil composition. . When the content of the component (A) is less than 0.035% by mass in terms of boron based on the total amount of the lubricating oil composition,
It is not preferable because the effect of improving the friction coefficient of the wet clutch by the component (A) is poor. On the other hand, the upper limit of the amount of component (A) is not particularly limited, but in order to maintain the storage stability and low-temperature fluidity of the lubricating oil composition,
0.5% by mass as boron based on the total amount of the lubricating oil composition
Is more preferably 0.3% by mass, particularly preferably 0.2% by mass.

The component (B) in the lubricating oil composition of the present invention is an alkaline earth metal sulfonate having a total base number of 50 to 500 mgKOH / g. The lower limit of the total base number of the alkaline earth metal sulfonate of the component (B) is 50 mgKOH /
g, preferably 100 mg KOH / g, more preferably 150 mg KOH / g, while the upper limit is 50 mg KOH / g.
0 mgKOH / g, more preferably 450 mgKOH / g
g. When the total base number is less than 50 mgKOH / g, the effect of increasing the friction coefficient of the wet clutch is poor.
When the total base number exceeds 500 mgKOH / g, the storage stability of the lubricating oil composition may be adversely affected, which is not preferable. Here, the total base number is defined in JIS K2501 "Petroleum products and lubricating oils-Neutralization number test method". Means the total base number measured by the perchloric acid method in accordance with

The alkaline earth metal used in the present invention is preferably magnesium or calcium.

The alkaline earth metal sulfonates include:
More specifically, for example, alkaline earth metal salts of alkyl aromatic sulfonic acids, particularly magnesium salts and / or calcium salts, obtained by sulfonating alkyl aromatic compounds having a molecular weight of 100 to 1500, preferably 200 to 700. Is preferably used. Specific examples of the alkyl aromatic sulfonic acid include so-called petroleum sulfonic acid and synthetic sulfonic acid.

As the petroleum sulfonic acid, generally used are those obtained by sulfonating an alkyl aromatic compound of a lubricating oil fraction of a mineral oil and so-called mahoganic acid which is a by-product of white oil production. Examples of the synthetic sulfonic acid include, as a raw material, an alkylbenzene having a linear or branched alkyl group, which is obtained as a by-product from an alkylbenzene production plant, which is a raw material of a detergent, or obtained by alkylating a polyolefin to benzene. And those obtained by sulfonating this, or those obtained by sulfonating dinonylnaphthalene. The sulfonating agent for sulfonating these alkyl aromatic compounds is not particularly limited, but fuming sulfuric acid or sulfuric acid is usually used. Alkaline earth metal sulfonates are usually commercially available in a diluted state with a light lubricating base oil or the like, and are available, but generally have a metal content of 1.0 to 2%.
It is desirable to use 0 mass%, preferably 2.0 to 16 mass%.

In the lubricating oil composition of the present invention, the lower limit of the amount of the component (B) is 0.01% by mass, preferably 0.0% by mass, as alkaline earth metal, based on the total amount of the lubricating oil composition.
2% by mass. When the amount of the component (B) is less than 0.01% by mass based on the total amount of the lubricating oil composition, the effect of increasing the friction coefficient of the wet clutch is poor, which is not preferable.
The upper limit of the amount of the component (B) is not particularly limited. However, in order to maintain the storage stability and the oxidation stability of the lubricating oil composition, the upper limit is 0.5% based on the total amount of the lubricating oil composition.
% By mass, more preferably 0.4% by mass.
% By mass, and particularly preferably 0.3% by mass.

The lubricating oil composition of the present invention preferably further contains (C) a phosphorus-based additive. By adding the component (C), the friction coefficient of the wet clutch can be further improved. In the present invention, the component (C) includes, for example, zinc alkyldithiophosphate, phosphoric acid, phosphorous acid, phosphoric acid monoesters, phosphoric acid diesters, phosphoric acid triesters, phosphorous acid monoesters, and phosphorous acid Acid diesters, phosphite triesters,
(A) Salts of phosphoric acid esters, and mixtures thereof.

Of the components (C) listed above, phosphoric acid,
Those other than phosphorous acid are usually compounds containing a hydrocarbon group having 2 to 30 carbon atoms, preferably 3 to 20 carbon atoms. As the hydrocarbon group having 2 to 30 carbon atoms, specifically,
For example, the following alkyl group, cycloalkyl group, alkyl-substituted cycloalkyl group, alkenyl group, aryl group,
Examples include an alkyl-substituted aryl group and an aryl-substituted alkyl group.

Examples of the alkyl group include an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group,
Heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group,
Examples thereof include alkyl groups such as a pentadecyl group, a hexadecyl group, a heptadecyl group, and an octadecyl group (the alkyl groups may be linear or branched).

Examples of the cycloalkyl group include a cycloalkyl group having 5 to 7 carbon atoms such as a cyclopentyl group, a cyclohexyl group and a cycloheptyl group; examples of the alkylcycloalkyl group include methylcyclopentyl Group, dimethylcyclopentyl, methylethylcyclopentyl, diethylcyclopentyl, methylcyclohexyl, dimethylcyclohexyl, methylethylcyclohexyl, diethylcyclohexyl, methylcycloheptyl, dimethylcycloheptyl, methylethylcycloheptyl, diethylcyclo Examples thereof include an alkylcycloalkyl group having 6 to 11 carbon atoms such as a heptyl group (the substitution position of the alkyl group with the cycloalkyl group is also arbitrary).

The alkenyl group includes, for example, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group,
Alkenyl groups such as octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecenyl and octadecenyl (these alkenyl groups may be linear or branched; And the position of the double bond is also arbitrary).

Examples of the aryl group include aryl groups such as a phenyl group and a naphthyl group. : Examples of the alkylaryl group include a tolyl group, a xylyl group, an ethylphenyl group, a propylphenyl group, a butylphenyl group, a pentylphenyl group, a hexylphenyl group, a heptylphenyl group, an octylphenyl group, a nonylphenyl group, and a decylphenyl. Alkylaryl groups having 7 to 18 carbon atoms such as a group, undecylphenyl group, dodecylphenyl group, etc. (the alkyl group may be linear or branched, and the substitution position of the aryl group is arbitrary)
Can be mentioned. As arylalkyl groups, for example, arylalkyl groups having 7 to 12 carbon atoms such as benzyl group, phenylethyl group, phenylpropyl group, phenylbutyl group, phenylpentyl group and phenylhexyl group (these alkyl groups are directly Chain or branched).

Examples of the above-mentioned (phosphite) salts of phosphoric acid esters include, for example, phosphoric acid monoester, phosphoric acid diester, phosphorous acid monoester, phosphorous acid diester, etc. Salts obtained by reacting a nitrogen-containing compound such as an amine compound containing only 1 to 8 hydrocarbon groups or hydroxyl group-containing hydrocarbon groups in the molecule to neutralize a part or all of the remaining acidic hydrogen can be exemplified. . Specific examples of the nitrogen-containing compound include ammonia; monomethylamine, monoethylamine, monopropylamine, monobutylamine, monopentylamine, monohexylamine, monoheptylamine, monooctylamine, dimethylamine, methylethylamine, and diethylamine. And alkylamines such as methylpropylamine, ethylpropylamine, dipropylamine, methylbutylamine, ethylbutylamine, propylbutylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, and dioctylamine. May be branched); monomethanolamine, monoethanolamine, monopropanolamine, monobutanolamine, monopentanolamine, monohexanolamine, Heptanolamine, monooctanolamine, monononanolamine, dimethanolamine, methanolethanolamine, diethanolamine, methanolpropanolamine, ethanolpropanolamine, dipropanolamine, methanolbutanolamine, ethanolbutanolamine, propanolbutanolamine, dibutanolamine, Alkanolamines such as dipentanolamine, dihexanolamine, diheptanolamine, and dioctanolamine (alkanol groups may be linear or branched); and mixtures thereof. One or more of these components (C) can be arbitrarily compounded.

Specific examples of preferred compounds as component (C) include phosphoric acid; phosphorous acid; zinc dipropyldithiophosphate, zinc dibutyldithiophosphate, zinc dipentyldithiophosphate, zinc dihexyldithiophosphate, and diheptyldithiophosphate. Zinc, zinc alkyldithiophosphate such as zinc dioctyldithiophosphate (the alkyl group may be linear or branched); monopropyl phosphate, monobutyl phosphate, monopentyl phosphate, monohexyl phosphate, monoheptyl phosphate, monooctyl Monoalkyl phosphates such as phosphate (the alkyl group may be linear or branched); Mono (alkyl) aryl phosphates such as monophenyl phosphate and monocresyl phosphate; dipropyl phosphate, dibutyl Phosphate dialkyl esters such as phosphate, dipentyl phosphate, dihexyl phosphate, diheptyl phosphate and dioctyl phosphate (the alkyl group may be linear or branched); di (alkyl) phosphate such as diphenyl phosphate and dicresyl phosphate Aryl esters; trialkyl phosphates such as tripropyl phosphate, tributyl phosphate, tripentyl phosphate, trihexyl phosphate, tripeptyl phosphate and trioctyl phosphate (the alkyl group may be linear or branched);

Tri (alkyl) aryl phosphates such as triphenyl phosphate and tricresyl phosphate; monopropyl phosphite, monobutyl phosphite, monopentyl phosphite, monohexyl phosphite, monoheptyl phosphite, monooctyl Phosphite monoalkyl phosphite (alkyl group may be linear or branched); phosphite mono (alkyl) aryl ester such as monophenyl phosphite, monocresyl phosphite; dipropyl phosphite Phyte, dibutyl phosphite, dipentyl phosphite,
Dialkyl phosphites such as dihexyl phosphite, dipeptyl phosphite and dioctyl phosphite (the alkyl group may be linear or branched); diphosphites such as diphenyl phosphite and dicresyl phosphite Alkyl) aryl esters; trialkyl phosphites such as tripropyl phosphite, tributyl phosphite, tripentyl phosphite, trihexyl phosphite, tripeptyl phosphite, and trioctyl phosphite; May be branched); tri (alkyl) aryl phosphites such as triphenyl phosphite and tricresyl phosphite; salts of the above (sub) phosphites; and mixtures thereof.

When the component (C) is blended in the lubricating oil composition of the present invention, its blending amount is not particularly limited, but it is necessary to obtain the effect of improving the friction coefficient of a wet clutch and the excellent oxidation stability of the lubricating oil composition. Preferably, the phosphorus content is in the range of 0.005 to 0.2% by mass, more preferably 0.01 to 0.1% by mass, based on the total amount of the lubricating oil composition.
It is in the range of 5% by mass.

In the present invention, the friction coefficient of the wet clutch can be reduced by blending the components (A) and (B) in specific amounts with the lubricating base oil, and more preferably by blending the component (C). A high lubricating oil composition can be obtained. For the purpose of further improving the performance, if necessary, furthermore, an ashless dispersant other than the component (A), a metal detergent other than the component (B), a friction modifier, a viscosity index improver,
Various additives typified by extreme pressure additives, antioxidants, corrosion inhibitors, defoamers, coloring agents, etc. may be used alone or in combination of several kinds.

Hereinafter, these additives will be described.
Specific examples of the ashless dispersant other than the component (A) of the present invention which can be used in combination with the lubricating oil composition of the present invention include a succinimide-based ashless dispersant containing no boron. Examples of the succinimide-based ashless dispersant mentioned here include the component represented by (A-1) or a derivative thereof. By using these ashless dispersants in combination, it is possible to further improve the cleanliness of the lubricating oil. In the present invention, one or more compounds arbitrarily selected from these ashless dispersants can be blended in an arbitrary amount. The compounding amount is usually in the range of 0.05 to 10% by mass, and preferably in the range of 1 to 7% by mass, based on the total amount of the lubricating oil composition.

As the metallic detergent which can be used in combination with the lubricating oil composition of the present invention, any compound other than the component (B) which is usually used as a metallic detergent for lubricating oils can be used. Examples of these include alkali metal or alkaline earth metal phenates, salicylates, and naphthenates. These can be used alone or in combination of two or more. Here, it is preferable that the alkali metal is sodium or potassium, and that the alkaline earth metal is calcium or magnesium. As a specific metal detergent, calcium or magnesium phenates and salicylates are preferably used. The total base number and the amount of these metal detergents can be arbitrarily selected according to the required performance of the lubricating oil.

As the friction modifier which can be used in combination with the lubricating oil composition of the present invention, any compound usually used as a friction modifier for lubricating oils can be used. In particular,
For example, an amine compound, a fatty acid ester, a fatty acid amide and a fatty acid metal salt having at least one alkyl group or alkenyl group having 6 to 30 carbon atoms, particularly a linear alkyl group or linear alkenyl group having 6 to 30 carbon atoms, in the molecule. Can be mentioned. Examples of the amine compound include linear or branched, preferably linear aliphatic monoamines having 6 to 30 carbon atoms, linear or branched, preferably linear aliphatic polyamines, and these. Can be exemplified. As the fatty acid ester, a linear or branched C7-C31,
Preferably, an ester of a linear fatty acid with an aliphatic monohydric alcohol or an aliphatic polyhydric alcohol can be exemplified.
Examples of the fatty acid amide include an amide of a linear or branched, preferably linear, fatty acid having 7 to 31 carbon atoms and an aliphatic monoamine or an aliphatic polyamine.
Examples of the fatty acid metal salt include an alkaline earth metal salt (such as a magnesium salt and a calcium salt) and a zinc salt of a linear or branched, preferably linear, fatty acid having 7 to 31 carbon atoms. . In the present invention, one or more compounds arbitrarily selected from these friction modifiers can be contained in an arbitrary amount. The content of the friction modifier is usually 0.01% based on the total amount of the lubricating oil composition.
To 5.0% by mass, preferably 0.03 to 3.0% by mass.

As the viscosity index improver which can be used in combination with the lubricating oil composition of the present invention, specifically, a polymer, copolymer or copolymer of one or more monomers selected from various methacrylates Examples thereof include a so-called non-dispersion type viscosity index improver such as a hydrogenated product thereof, and a so-called dispersion type viscosity index improver obtained by copolymerizing various methacrylates containing a nitrogen compound. Specific examples of other viscosity index improvers include non-dispersed or dispersed ethylene-α
-Olefin copolymers (examples of α-olefins include propylene, 1-butene, 1-pentene, etc.) and hydrides thereof, polyisobutylene and hydrogenated products thereof, styrene-diene copolymer hydrides, styrene- Mention may be made of maleic anhydride copolymers, polyalkylstyrenes and the like.

The molecular weight of these viscosity index improvers is selected in consideration of shear stability. Specifically, the number average molecular weight of the viscosity index improver is, for example, 5,000 to 150,000 in the case of a dispersion type and a non-dispersion type polymethacrylate.
0, preferably 5,000 to 35,000 is 800 to 5,5 in the case of polyisobutylene or a hydride thereof.
000, preferably 1,000 to 4,000,
In the case of an ethylene-α-olefin copolymer or a hydride thereof, 800 to 150,000, preferably 3,000
~ 12,000 are preferred. When an ethylene-α-olefin copolymer or a hydride thereof is used among these viscosity index improvers, a lubricating oil composition having particularly excellent shear stability can be obtained. In the present invention, one or two or more compounds arbitrarily selected from these viscosity index improvers can be blended in an arbitrary amount. The compounding amount of the viscosity index improver is usually in the range of 0.1 to 40.0% by mass based on the total amount of the lubricating oil composition.

As the extreme pressure additive that can be used in combination with the lubricating oil composition of the present invention, any compound usually used as an extreme pressure additive for a lubricating oil can be used. Examples of these include sulfur compounds such as disulfides, sulfurized olefins, sulfurized oils and the like. One or more compounds arbitrarily selected from these extreme pressure additives can be blended in an arbitrary amount. The amount of the extreme pressure additive is usually 0.01 to 5.0 based on the total amount of the lubricating oil composition.
% By mass.

Examples of the antioxidant which can be used in combination with the lubricating oil composition of the present invention include those generally used in lubricating oils such as phenolic compounds and amine compounds. Specifically, for example, 2,6-di-t
alkylphenols such as tert-butyl-4-methylphenol; methylene-4,4-bisphenol (2,6
Bisphenols such as -di-tert-butyl-4-methylphenol); naphthylamines such as phenyl-α-naphthylamine; dialkyldiphenylamines; zinc dialkyldithiophosphates such as zinc di-2-ethylhexyldithiophosphate; and (3 , 5-di-tert-butyl-4-hydroxyphenyl) fatty acid (such as propionic acid) and a monohydric or polyhydric alcohol such as methanol, octadecanol, 1,6 hexadiol, neopentyl glycol, thiodiethylene glycol, and triethylene Examples thereof include esters with glycol, pentaerythritol and the like. One or more compounds arbitrarily selected from these antioxidants can be blended in an arbitrary amount. In the present invention, it is preferable to use an amine compound and a phenol compound in combination. The compounding amount of the antioxidant is usually 0.1% based on the total amount of the lubricating oil composition.
0.01 to 5.0% by mass.

As the corrosion inhibitor usable in combination with the lubricating oil composition of the present invention, any compound usually used as a corrosion inhibitor for lubricating oils can be used. Examples thereof include benzotriazole, tolyltriazole, thiadiazole and imidazole compounds. One or more compounds arbitrarily selected from these corrosion inhibitors can be blended in an arbitrary amount. The compounding amount of the corrosion inhibitor is usually 0.01 to 3.0% by mass based on the total amount of the lubricating oil composition.

As the antifoaming agent which can be used in combination with the lubricating oil composition of the present invention, any compound which is usually used as an antifoaming agent for lubricating oils can be used. Examples of these include silicones such as dimethyl silicone and fluorosilicone. One or more compounds arbitrarily selected from these defoaming agents can be blended in an arbitrary amount. The compounding amount of the antifoaming agent is usually 0.001 to 0.05% by mass based on the total amount of the lubricating oil composition.

The colorant that can be used in combination with the lubricating oil composition of the present invention is optional and may be added in any amount.
The amount of the coloring agent is usually 0.0% based on the total amount of the lubricating oil composition.
0.01 to 1.0% by mass.

[0056]

EXAMPLES Hereinafter, the content of the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

(Preparation of lubricating oil composition) According to the composition shown in Table 1, the lubricating oil composition according to the present invention (Examples 1 to 4) and the lubricating oil composition for comparison (Comparative Examples 1 to 4) were prepared. Prepared.

(Evaluation of Performance by Friction Property Test) A friction property test of a wet clutch was carried out for each composition. The friction characteristics test of the wet clutch was performed according to JASO M348-95.
SAE based on "Test Method for Oil Friction Characteristics of Automatic Transmission"
No. The test was performed on two test machines. This test consists of a dynamic friction test and a static friction test.
After rotating without load at 00 rpm and an inertial mass of 0.343 kg · m, the clutch is pressed by applying pressure to stop the rotation. The friction coefficient was calculated from the torque generated when the relative rotation speed of the clutch was 1800 rpm, and this was arranged as a dynamic friction coefficient. In the static friction test, the clutch pressed and pressed is rotated at a relative rotational speed of 0.72 rpm, and the friction coefficient is calculated from the torque generated at this time. The friction coefficient at the maximum torque at which the clutch slips at low speed rotation was arranged as the static friction coefficient. In the test, a dynamic friction test and a static friction test were repeatedly performed, and the friction coefficient improvement performance of each composition was evaluated at a friction coefficient of 1000 cycles.

[0059]

[Table 1]

Notes: 1) Hydrorefined mineral oil (kinematic viscosity at 100 ° C. 4 mm ² / s,
Clay index 120) 2) Boron-modified polybutenyl succinimide (monotype, weight average molecular weight of polybutenyl group 1000, boron content 2% by mass) 3) Boron-modified polybutenyl succinimide (bis type, polybutenyl group 4) Polybutenyl succinimide (monotype, weight average molecular weight of polybutenyl group 1000, not containing boron) 5) Petroleum Ca sulfonate (total base number 300 mg KO)
H / g, Ca content 12.2% by mass) 6) Petroleum-based Mg sulfonate (total base number 400 mg KO)
H / g, Mg content 9.4% by mass) 7) Synthetic Ca sulfonate (total base number 13 mg KOH)
/ G, Ca content 2.5% by mass) 8) Diphenyl hydrogen phosphite (phosphorus content 13.2% by mass) 9) Dispersion type polymethacrylate 10) Dialkyldiphenylamine type 11) Bisphenol type 12) Amine type 13 ) Amides 14) Tolyltriazole 15) Polydimethylsiloxane

As is clear from the results shown in Table 1, the lubricating oil compositions of Examples 1 to 4 according to the present invention all have high dynamic friction coefficients and high static friction coefficients, and have an excellent effect of improving the friction coefficient of a wet clutch. are doing. In contrast, in the case of a lubricating oil composition containing an ashless dispersant containing no boron (Comparative Example 1), when the boron content in the lubricating oil composition is less than the range specified in the present invention (Comparative Example 2) The case where the alkaline earth metal content in the lubricating oil composition is less than the range specified in the present invention (Comparative Example 3) and the case where the total base number of the alkaline earth metal sulfonate is smaller than the range specified in the present invention (Comparative Example) In Example 4), the coefficient of friction is low.

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Claims (3)

[Claims] 1. A lubricating base oil containing (A) a boron-containing ashless dispersant in an amount of 0.035% by mass or more based on the total amount of the composition, and (B) a total base number of 50 to 500 mg KOH.
/ G of alkaline earth metal sulfonate in an amount of 0.01% by mass or more as alkaline earth metal based on the total amount of the composition. 2. The lubricating oil composition according to claim 1, further comprising (C) a phosphorus-based additive. 3. The lubricating oil composition according to claim 1, which is used for an automatic transmission or a continuously variable transmission.