JP4878441B2 - Lubricating oil composition - Google Patents

Description

  The present invention relates to a lubricating oil composition.

  Conventionally, lubricating oil for hydraulic actuators (hereinafter referred to as “hydraulic hydraulic oil”) has been widely used in fields such as construction machinery. In general, hydraulic fluid is blended with an anti-wear additive such as zinc dithiophosphate (ZnDTP) in order to impart anti-wear properties.

  However, in recent years, higher and higher characteristics have been demanded of hydraulic fluids, and the development of new hydraulic fluids is desired because the above-mentioned hydraulic fluids are difficult to meet such requirements. .

  For example, in recent years, in the field of construction machinery and the like, hydraulic actuators have become smaller and faster, and hydraulic actuators have been increased in pressure. Accordingly, higher wear resistance is required for hydraulic fluids.

  Construction machinery is also used in tropical regions. In this case, the oil temperature of the hydraulic fluid may exceed 100 ° C. Therefore, the hydraulic fluid for construction machinery is required to exhibit excellent wear resistance even at such a high temperature. Yes.

  Further, in the case of hydraulic fluid, there is a tendency that a deteriorated base oil or additive is gradually generated as the usage time increases. Accordingly, the hydraulic fluid is required to have characteristics that hardly cause deterioration of the base oil and additives, and that the generated deterioration is less likely to precipitate as sludge.

  Furthermore, the hydraulic operation system is becoming more sophisticated, and the flow rate and direction of the hydraulic system are controlled by a valve such as a spool valve to perform high-speed and high-precision control, and a servo valve is installed. Although the number of cases has increased, it is known that the performance of a valve such as a spool valve or a servo valve is greatly reduced by sludge in hydraulic fluid. For this reason, there is a strong demand for sludge-less hydraulic fluid that does not generate sludge, as well as excellent wear resistance, as a hydraulic fluid used in recent high-performance systems.

Therefore, various attempts have been made to improve the characteristics of hydraulic fluid. For example, for the purpose of ensuring abrasion resistance while preventing the generation of sludge, instead of ZnDTP, aromatic phosphate ester, phosphite ester and amine salt thereof, thiophosphate, β-dithiophosphorylation The use of non-zinc hydraulic fluids containing non-zinc wear inhibitors such as propionic acid compounds has been proposed. (For example, refer to Patent Documents 1 and 2).
JP-A-10-67993 JP 2002-265971 A

  However, even the above-described conventional hydraulic fluids have room for improvement in the following points and are not necessarily sufficient for practical use.

  For example, non-zinc-based antiwear agents such as aromatic phosphate esters, phosphite esters and their amine salts, and thiophosphate are effective in suppressing sludge as compared to ZnDTP, but sludge when used for a long time. May occur. Moreover, these non-zinc-based antiwear agents tend to be inferior in wear resistance as compared to ZnDTP.

  In addition, when a β-dithiophosphorylated propionic acid compound is used as an antiwear agent, a sufficient effect may not be obtained in terms of sludge suppression, especially when the compound is used alone. This tendency becomes remarkable.

  In addition to the above, means for suppressing sludge include a method of adding an ashless dispersant such as succinimide, a metal detergent such as calcium sulfonate, and the like to the hydraulic fluid. However, since hydraulic fluids that may be mixed with water are required to have good water separation properties, the use of succinimide or calcium sulfonate that adversely affects water separation performance is a fundamental solution. It can't be.

  The present invention has been made in view of such circumstances, and provides a lubricating oil composition that is excellent in wear resistance and sludge suppression, and suitable for applications such as hydraulic fluids used under high temperature and high pressure. The purpose is to do.

［式中、Ｒ^１５は水素原子又はメチル基を示し、Ｒ^１６は炭素数１〜１８のアルキル基を示す。］

［式中、Ｒ^１７は水素原子又はメチル基を示し、Ｒ^１８は炭素数１〜１２の炭化水素基を示す。］

［式中、Ｙ^１及びＹ^２は同一でも異なっていてもよく、それぞれ水素原子、炭素数１〜１８のアルコキシ基、又は炭素数１〜１８のモノアルキルアミノ基を示す。］

［式中、Ｒ^１９は水素原子又はメチル基を示し、Ｒ^２０は炭素数２〜１８のアルキレン基を示し、ａは０又は１を示し、Ｙ^３は窒素原子を含有する炭素数１〜３０の有機基を示す。］

［式中、Ｒ^２１は水素原子又はメチル基を示し、Ｙ^４は窒素原子を含有する炭素数１〜３０の有機基を示す。］ In order to solve the above-mentioned problems, the lubricating oil composition of the present invention comprises at least one base oil selected from mineral oils, fats and oils, phosphorus-containing carboxylic acid compounds, and phosphorus other than the phosphorus-containing carboxylic acid compounds. A phosphorus-based antiwear agent containing no sulfur, a compound represented by the following general formula (8), (9) or (10), or one or more monomers selected from the following general formula: Improved dispersion type viscosity index, which is a copolymer with one or more monomers selected from compounds represented by formula (11) or (12) and has a number average molecular weight of 10,000 to 200,000 It contains an agent, an ester oily agent, and magnesium sulfonate .

[Wherein, R ¹⁵ represents a hydrogen atom or a methyl group, and R ¹⁶ represents an alkyl group having 1 to 18 carbon atoms. ]

[Wherein, R ¹⁷ represents a hydrogen atom or a methyl group, and R ¹⁸ represents a hydrocarbon group having 1 to 12 carbon atoms. ]

[Wherein Y ¹ and Y ² may be the same or different and each represents a hydrogen atom, an alkoxy group having 1 to 18 carbon atoms, or a monoalkylamino group having 1 to 18 carbon atoms. ]

[Wherein, R ¹⁹ represents a hydrogen atom or a methyl group, R ²⁰ represents an alkylene group having 2 to 18 carbon atoms, a represents 0 or 1, and Y ³ represents 1 to 30 carbon atoms containing a nitrogen atom. An organic group of ]

[Wherein, R ²¹ represents a hydrogen atom or a methyl group, and Y ⁴ represents a C 1-30 organic group containing a nitrogen atom. ]

Thus, a phosphorus-containing carboxylic acid compound, a phosphorus-containing compound other than the phosphorus-containing carboxylic acid compound and containing no sulfur (hereinafter, simply referred to as “phosphorus-based antiwear agent”), One or more monomers selected from compounds represented by formula (8), (9) or (10), and one compound selected from compounds represented by the following general formula (11) or (12) Alternatively, a dispersion type viscosity index improver having a number average molecular weight of 10,000 to 200,000, an ester oiliness agent, and magnesium sulfonate, which is a copolymer with two or more kinds of monomers, is used as a predetermined base oil. By blending, it becomes possible to realize a lubricating oil composition that maintains a sufficient level of water separation while achieving a high level of wear resistance, sludge suppression, and further frictional properties in a well-balanced manner. Therefore, the lubricating oil composition of the present invention can exhibit sufficient wear resistance or further friction characteristics even under high temperature and high pressure, and it can generate sludge sufficiently even if it is used for a long time. Can be suppressed.

  According to the present invention, it is possible to realize a lubricating oil composition that is excellent in wear resistance, sludge suppression and water separation properties, and also has excellent friction characteristics. Such lubricating oil compositions are suitable for applications such as hydraulic fluids used at high temperatures and high pressures.

  Hereinafter, preferred embodiments of the present invention will be described in detail.

  The lubricating oil composition of the present invention comprises at least one base oil selected from mineral oil, fat and synthetic oil, (A) a phosphorus-containing carboxylic acid compound, (B) a phosphorus-based antiwear agent, and (C) a dispersion. And a mold viscosity index improver.

  Among the base oils used in the present invention, as the mineral oil, the lubricating oil fraction obtained by subjecting the crude oil to atmospheric distillation and reduced pressure distillation, solvent removal, solvent extraction, hydrocracking, solvent dewaxing, Mention may be made of paraffinic or naphthenic mineral oils obtained by applying a suitable combination of one or more purification means such as catalytic dewaxing, hydrorefining, sulfuric acid washing and clay treatment. Examples of the fats and oils include beef tallow, lard, sunflower oil, soybean oil, rapeseed oil, rice bran oil, coconut oil, palm oil, palm kernel oil, and hydrogenated products thereof.

  Synthetic oils include, for example, poly α-olefins (ethylene-propylene copolymer, polybutene, 1-octene oligomer, 1-decene oligomer, and hydrides thereof), alkylbenzene, alkylnaphthalene, monoester (butyl). Stearate, octyl laurate), diester (ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, di-2-ethylhexyl sepacate, etc.), polyester (trimellitic acid ester, etc.), polyol ester (Trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate, pentaerythritol pelargonate, etc.), polyoxyalkylene glycol Lumpur, polyphenyl ether, dialkyl diphenyl ether, phosphate ester (tricresyl phosphate, etc.), fluorine-containing compound (perfluoropolyether, fluorinated polyolefin and the like), silicone oils and the like. As a base oil of the lubricating oil composition of the present invention, the above base oils may be used alone or in combination of two or more.

  Among the above-mentioned base oils, it is preferable to use a mineral oil that has been subjected to hydrocracking treatment from the viewpoint of obtaining better sludge suppression.

The kinematic viscosity of the base oil used in the present invention is not particularly limited, but is usually kinematic viscosity at 40 ° C. from the viewpoints of excellent friction characteristics, cooling properties (heat removal properties), and low friction loss due to stirring resistance. Is preferably 5 to 1,000 mm ² / s, more preferably 7 to 500 mm ² / s, and still more preferably 10 to 200 mm ² / s. The viscosity index of the base oil is not particularly limited, but is preferably 80 to 500, and more preferably 100 to 300, from the viewpoint of suppressing oil film deterioration at high temperatures. Furthermore, although the pour point is also arbitrary, from the viewpoint of pump startability in winter, the pour point is usually preferably −5 ° C. or lower, more preferably −15 ° C. or lower.

As the (A) phosphorus-containing carboxylic acid compound, abrasion resistance and sludge inhibitory, or from further friction characteristics point, preferably phosphoryl carboxylic acid.

［式（１）中、Ｒ^１及びＲ^２は同一でも異なっていてもよく、それぞれ水素原子又は炭素数１〜３０の炭化水素基を示し、Ｒ^３は炭素数１〜２０のアルキレン基を示し、Ｒ^４は水素原子又は炭素数１〜３０の炭化水素基を示し、炭素数Ｘ^１、Ｘ^２、Ｘ^３及びＸ^４は同一でも異なっていてもよく、それぞれ酸素原子又は硫黄原子を示す。］ Examples of the phosphorylated carboxylic acid include compounds represented by the following general formula (1).

[In Formula (1), R ¹ and R ² may be the same or different, and each represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, and R ³ represents an alkylene group having 1 to 20 carbon atoms. , R ⁴ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, and the carbon numbers X ¹ , X ² , X ³ and X ⁴ may be the same or different and each represents an oxygen atom or a sulfur atom. ]

［式（２）中、Ｒ^５及びＲ^６は同一でも異なっていてもよく、それぞれ水素原子又は炭素数１〜４のアルキル基を示し、Ｒ^５及びＲ^６の双方がメチル基であることが好ましい。］
Ｒ^１及びＲ^２としては、これらの中でもアルキル基、シクロアルキル基、シクロアルキルアルキル基、トリシクロアルキルアルキル基、アリール基、アルキルアリール基、Ｒ^１とＲ^２とが結合した上記一般式（２）で表されるような２価の基であることが好ましく、アルキル基であることがより好ましい。 In General Formula (1), R ¹ and R ² each represent a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. Examples of the hydrocarbon group having 1 to 30 carbon atoms include an alkyl group, an alkenyl group, a cycloalkyl group, a bicycloalkyl group, a tricycloalkyl group, an alkylcycloalkyl group, an alkylbicycloalkyl group, an alkyltricycloalkyl group, and a cycloalkylalkyl. Group, bicycloalkylalkyl group, tricycloalkylalkyl group, aryl group, alkylaryl group, arylalkyl group and the like. R ¹ and R ² may be bonded to form a divalent group represented by the following general formula (2). The two bonds of the divalent group are bonded to X ¹ and X ² , respectively.

[In the formula (2), R ⁵ and R ⁶ may be the same or different, each represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and both R ⁵ and R ⁶ are methyl groups. preferable. ]
R ¹ and R ² include, among these, an alkyl group, a cycloalkyl group, a cycloalkylalkyl group, a tricycloalkylalkyl group, an aryl group, an alkylaryl group, and the above general formula (2) in which R ¹ and R ² are bonded. ) Is preferably a divalent group, and more preferably an alkyl group.

The alkyl group as R ¹ and R ² may be linear or branched. The alkyl group preferably has 1 to 18 carbon atoms. Specific examples of such alkyl groups include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, isopentyl, hexyl, heptyl, 3-heptyl, octyl, 2-ethylhexyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, 2-ethylbutyl, 1-ethyl Methylphenyl group, 1,3-dimethylbutyl group, 1,1,3,3-tetramethylbutyl group, 1-methylhexyl group, isoheptyl group, 1-methylheptyl group, 1,1,3-trimethylhexyl group and Examples include 1-methylundecyl group. Among these, a C3-C18 alkyl group is preferable and a C3-C8 alkyl group is more preferable.

Examples of the cycloalkyl group as R ¹ and R ² include a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, and a cyclododecyl group. Among these, a cycloalkyl group having 5 or 6 carbon atoms (cyclopentyl group and cyclohexyl group) is preferable, and a cyclohexyl group is particularly preferable.

The cycloalkylalkyl group as R ¹ and R ² is preferably a cycloalkylmethyl group, more preferably a cycloalkylmethyl group having 6 or 7 carbon atoms, and particularly preferably a cyclopentylmethyl group and a cyclohexylmethyl group.

As the bicycloalkylalkyl group as R ¹ and R ² , a bicycloalkylmethyl group is preferable, a bicycloalkylmethyl group having 9 to 11 carbon atoms is more preferable, and a decalinylmethyl group is particularly preferable.

The tricycloalkylalkyl group as R ¹ and R ² is preferably a tricycloalkylmethyl group, more preferably a tricycloalkylmethyl group having 9 to 15 carbon atoms, represented by the following formula (3) or (4). Particularly preferred are the groups

As the aryl group and alkylaryl group as R ¹ and R ² , phenyl group, tolyl group, xylyl group, ethylphenyl group, vinylphenyl group, methylphenyl group, dimethylphenyl group, trimethylphenyl group, ethylphenyl group, isopropyl Examples thereof include a phenyl group, a tert-butylphenyl group, a di-tert-butylphenyl group, and a 2,6-di-tert-butyl-4-methylphenyl group. Among these, an aryl group having 6 to 15 carbon atoms and an alkylaryl group are preferable.

R ³ represents an alkylene group having 1 to 20 carbon atoms. The number of carbon atoms of the alkylene group is preferably 1 to 10, more preferably 2 to 6, and further preferably 3 to 4. Moreover, as such an alkylene group, what is represented by following General formula (5) is preferable.

In the general formula (5), R ⁷ , R ⁸ , R ⁹ and R ¹⁰ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, and R ⁷ , R ⁸ , R The total number of carbon atoms of ⁹ and R ¹⁰ is 6 or less. Preferably, R ⁷ , R ⁸ , R ⁹ and R ¹⁰ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms, and R ⁷ , R ⁸ , R ⁹ and The total number of carbon atoms of R ¹⁰ is 5 or less. More preferably, R ⁷ , R ⁸ , R ⁹ and R ¹⁰ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 1 or 2 carbon atoms, and R ⁷ , R ⁸ , R ⁹ and R 10 The total of ¹⁰ carbon atoms is 4 or less. Particularly preferably, R ⁷ , R ⁸ , R ⁹ and R ¹⁰ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 1 to 2 carbon atoms, and R ⁷ , R ⁸ , R ⁹ and R 10 The total of ¹⁰ carbon atoms is 3 or less. Most preferably, either R ⁹ or R ¹⁰ is a methyl group and the remaining three groups are hydrogen atoms.

In general formula (1) ^{R 4} in the show a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms. Examples of the hydrocarbon group include the hydrocarbon groups exemplified in the description of R ¹ and R ² . From the viewpoint of wear resistance, R ⁴ is preferably a hydrogen atom.

Further, X ¹ , X ² , X ³ and X ⁴ in the general formula (1) may be the same or different and each represents an oxygen atom or a sulfur atom. From the viewpoint of wear resistance, one or more of X ¹ , X ² , X ³ or X ⁴ are preferably sulfur atoms, more preferably two or more are sulfur atoms, and two are sulfur atoms. More preferably, the remaining two are oxygen atoms. In this case, it is arbitrary which of X ¹ , X ² , X ³ or X ⁴ is a sulfur atom, but X ¹ and X ² are oxygen atoms, and X ³ and X ⁴ are sulfur atoms. It is preferable.

［式（６）中、Ｒ^１、Ｒ^２はそれぞれ式（１）中のＲ^１、Ｒ^２と同一の定義内容を示し、Ｒ^７、Ｒ^８、Ｒ^９、Ｒ^１０はそれぞれ（５）中のＲ^７、Ｒ^８、Ｒ^９、Ｒ^１０と同一の定義内容を示す。］ As mentioned above, although each group in General formula (1) was demonstrated, since it is more excellent in abrasion resistance and a friction characteristic, (beta) -dithio phosphorylated propionic acid represented by following General formula (6) is used preferably. Is done.

Wherein ^(6), R 1, ^{R 2} represents a ^R 1, ^{R 2} identical definitions and their respective formulas ^{(1), R 7, R 8, R} 9, R 10 are each (5) The same definition content as R ⁷ , R ⁸ , R ⁹ , and R ¹⁰ is shown. ]

The content of the phosphorus-containing carboxylic acid compound in the lubricating oil composition of the present invention is not particularly limited, but is preferably 0.001 to 1% by mass, more preferably 0.002 to 0.5% by mass, based on the total amount of the composition. It is. When the content of the phosphorus-containing carboxylic acid compound is less than the lower limit value, the effect of improving the wear resistance and friction characteristics tends to be insufficient. On the other hand, when the content exceeds the upper limit value, the sludge inhibiting property tends to be lowered. In addition, among the phosphorylated carboxylic acids represented by the general formula (1), the compound containing R ⁴ is a hydrogen atom (including β-dithiophosphorylated propionic acid represented by the general formula (6)). The amount is preferably 0.001 to 0.1% by mass, more preferably 0.002 to 0.08% by mass, still more preferably 0.003 to 0.07% by mass, and still more preferably 0.004 to 0%. 0.06% by mass, particularly preferably 0.005 to 0.05% by mass. When the content is less than 0.001, the effect of improving wear resistance and friction characteristics tends to be insufficient. On the other hand, when the content exceeds 0.1% by mass, sludge suppression tends to be reduced.

  (B) Phosphorus antiwear agent is a phosphorus-containing compound other than (A) phosphorus-containing carboxylic acid compound and does not contain sulfur. Specifically, phosphoric monoester, phosphoric diester, phosphoric acid Phosphate esters such as triester; Phosphite monoester, phosphite diester, phosphite esters such as phosphite triester; salts of these phosphate esters and phosphites; and these A mixture etc. are mentioned. The above-described phosphate esters and phosphites are compounds containing a hydrocarbon group usually having 2 to 30 carbon atoms, preferably 3 to 20 carbon atoms.

  Specific examples of the hydrocarbon group having 2 to 30 carbon atoms include ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl. Group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, etc. (these alkyl groups may be linear or branched); butenyl group, pentenyl group, hexenyl group, heptenyl group Alkenyl groups such as octenyl group, nonenyl group, decenyl group, undecenyl group, dodecenyl group, tridecenyl group, tetradecenyl group, pentadecenyl group, hexadecenyl group, heptadecenyl group, octadecenyl group (these alkenyl groups may be linear or branched) Good, and the position of the double bond is arbitrary); C5-C7 cycloalkyl group such as pentyl group, cyclohexyl group, cycloheptyl group; methylcyclopentyl group, dimethylcyclopentyl group, methylethylcyclopentyl group, diethylcyclopentyl group, methylcyclohexyl group, dimethylcyclohexyl group, methylethylcyclohexyl group Alkylcycloalkyl groups having 6 to 11 carbon atoms such as diethylcyclohexyl group, methylcycloheptyl group, dimethylcycloheptyl group, methylethylcycloheptyl group, and diethylcycloheptyl group (the substitution position of the alkyl group to the cycloalkyl group is also arbitrary) Aryl groups such as phenyl group and naphthyl group: tolyl group, xylyl group, ethylphenyl group, propylphenyl group, butylphenyl group, pentylphenyl group, hexylphenyl group, heptyl Each alkylaryl group having 7 to 18 carbon atoms such as an phenyl group, an octylphenyl group, a nonylphenyl group, a decylphenyl group, an undecylphenyl group, a dodecylphenyl group (the alkyl group may be linear or branched, The substitution position on the aryl group is also arbitrary); each arylalkyl group having 7 to 12 carbon atoms such as benzyl group, phenylethyl group, phenylpropyl group, phenylbutyl group, phenylpentyl group, phenylhexyl group (these alkyl groups) May be linear or branched).

  (B) Specific examples of preferable compounds as phosphorus wear inhibitors include monoalkyl phosphates such as monopropyl phosphate, monobutyl phosphate, monopentyl phosphate, monohexyl phosphate, monopeptyl phosphate, monooctyl phosphate and the like. Esters (alkyl groups may be linear or branched); mono (alkyl) aryl phosphates such as monophenyl phosphate and monocresyl phosphate; dipropyl phosphate, dibutyl phosphate, dipentyl phosphate, dihexyl phosphate, dipeptide Dialkyl phosphates such as ruphosphate and dioctyl phosphate (the alkyl group may be linear or branched); di (alkyl alkyl phosphates such as diphenyl phosphate and dicresyl phosphate Aryl ester; Trialkyl phosphate, tributyl phosphate, tripentyl phosphate, trihexyl phosphate, tripeptyl phosphate, trioctyl phosphate, etc. phosphoric acid trialkyl ester (alkyl group may be linear or branched); triphenyl Tri (alkyl) aryl phosphates such as phosphate and tricresyl phosphate; monopropyl phosphite, monobutyl phosphite, monopentyl phosphite, monohexyl phosphite, monopeptyl phosphite, monooctyl phosphite, etc. Phosphoric acid monoalkyl ester (alkyl group may be linear or branched); Phosphorous acid mono (alkyl) aryl ester such as monophenyl phosphite, monocresyl phosphite; Dialkyl phosphites such as ruphosphite, dibutyl phosphite, dipentyl phosphite, dihexyl phosphite, dipeptyl phosphite, dioctyl phosphite (the alkyl group may be linear or branched); diphenyl phosphite, dicrete Phosphorous acid di (alkyl) aryl esters such as phosphite; tripropyl phosphite, tributyl phosphite, tripentyl phosphite, trihexyl phosphite, tripeptyl phosphite, trioctyl phosphite Alkyl esters (the alkyl group may be linear or branched); tri (alkyl) aryl phosphites such as triphenyl phosphite and tricresyl phosphite; and mixtures thereof.

  Specific examples of the salts of the phosphoric acid esters and phosphite esters described above include phosphoric acid monoesters, phosphoric acid diesters, phosphorous acid monoesters, phosphorous acid diester esters, ammonia, carbon Examples include salts obtained by allowing a nitrogen-containing compound such as an amine compound containing only a hydrocarbon group of 1 to 8 or a hydroxyl group-containing hydrocarbon group in the molecule to act to neutralize part or all of the remaining acidic hydrogen. It is done.

  Specific examples of the nitrogen-containing compound include ammonia; monomethylamine, monoethylamine, monopropylamine, monobutylamine, monopentylamine, monohexylamine, monoheptylamine, monooctylamine, dimethylamine, methylethylamine, Alkylamines such as diethylamine, methylpropylamine, ethylpropylamine, dipropylamine, methylbutylamine, ethylbutylamine, propylbutylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, etc. May be branched); monomethanolamine, monoethanolamine, monopropanolamine, monobutanolamine, monopentanolamine, monohexanolamine , Monoheptanolamine, monooctanolamine, monononanolamine, dimethanolamine, methanolethanolamine, diethanolamine, methanolpropanolamine, ethanolpropanolamine, dipropanolamine, methanolbutanolamine, ethanolbutanolamine, propanolbutanolamine, dibutanol And alkanolamines such as amines, dipentanolamines, dihexanolamines, diheptanolamines, dioctanolamines (the alkanol groups may be linear or branched); and mixtures thereof.

  As a matter of course, as the (B) phosphorus-based antiwear agent, one of the above-mentioned compounds may be used alone, or two or more compounds selected from the above may be used. You may use the mixture in arbitrary mixing ratios.

  (B) Among phosphorous antiwear agents, among phosphoric acid esters and phosphites, phosphoric acid esters are preferable and phosphoric acid triesters are more preferable because of excellent thermal stability. The hydrocarbon group of the phosphate ester is preferably a phenyl group or an alkylphenyl group, more preferably a phenyl group or an alkylphenyl group having 1 to 10 carbon atoms, and a phenyl group or 1 to 5 carbon atoms. An alkylphenyl group having an alkyl group is more preferable, and a phenyl group or an alkylphenyl group having an alkyl group having 1 to 3 carbon atoms is particularly preferable.

  The content of the (B) phosphorus-based antiwear agent is preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 3% by mass or less, based on the total amount of the composition. Even if the content exceeds 5% by mass, the effect of further improving the wear resistance just commensurate with the content cannot be obtained, and the oxidation stability tends to decrease. On the other hand, the content of the phosphorus-based antiwear agent described above is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and further preferably 0.1% by mass or more, based on the total amount of the composition. . When the said content is less than 0.01 mass%, it exists in the tendency for the abrasion resistance by the addition to become inadequate.

  Further, (B) the phosphorus-based antiwear agent can contribute to the improvement of the friction characteristics of the lubricating oil composition of the present invention, but if the content of (B) the phosphorus-based additive exceeds the upper limit, the friction characteristics. Tends to be insufficient. Therefore, for example, when the lubricating oil composition of the present invention is used as a hydraulic fluid such as a hydraulic excavator, the friction characteristics between the inner surface of the cylinder body and the guide seal become insufficient, and the occurrence of squeal in the cylinder portion is prevented. Tend to be difficult.

  The lubricating oil composition of the present invention comprises an antiwear agent (hereinafter referred to as “a phosphorous wear inhibitor”) containing a phosphorus atom and a sulfur atom such as a zinc dithiophosphate compound and a phosphorothionate. It may further contain a “sulfur-containing phosphorus-based antiwear agent”.

［式中、Ｒ^１１、Ｒ^１２、Ｒ^１３及びＲ^１４は同一でも異なっていてもよく、それぞれ炭素数１以上の炭化水素基を表し、Ｘ¹及びＸ²は、それぞれ酸素原子又は硫黄原子を表す。］ Examples of the zinc dithiophosphate compound include compounds represented by the following general formula (7).

[Wherein R ¹¹ , R ¹² , R ¹³ and R ¹⁴ may be the same or different and each represents a hydrocarbon group having 1 or more carbon atoms, and X ¹ and X ² each represents an oxygen atom or a sulfur atom. To express. ]

Examples of the hydrocarbon group represented by R ^{16 to} R ³¹ include an alkyl group having 1 to 24 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, an alkylcycloalkyl group having 6 to 11 carbon atoms, and 2 carbon atoms. -24 alkenyl group, C6-C18 aryl group, C7-C24 alkylaryl group, and C7-C12 arylalkyl group can be mentioned.

  Specific examples of the phosphorothioate include tributyl phosphorothioate, tripentyl phosphorothioate, trihexyl phosphorothionate, triheptyl phosphorothionate, trioctyl phosphorothionate, trinonyl phosphorothioate. Thionate, tridecyl phosphorothioate, triundecyl phosphorothionate, tridodecyl phosphorothionate, tritridecyl phosphorothionate, tritetradecyl phosphorothionate, tripentadecyl phosphorothionate, trihexa Decyl phosphorothioate, triheptadecyl phosphorothionate, trioctadecyl phosphorothioate, trioleyl phosphorothionate, triphenyl phosphorothionate, tricresyl phosphorothione , Trixylenyl phosphorothioate, cresyl diphenyl phosphorothioate, xylenyl diphenyl phosphorothioate, tris (n-propylphenyl) phosphorothioate, tris (isopropylphenyl) phosphorothionate, tris (N-butylphenyl) phosphorothionate, tris (isobutylphenyl) phosphorothionate, tris (s-butylphenyl) phosphorothionate, tris (t-butylphenyl) phosphorothionate, and the like. Mixtures of these can also be used.

  In addition, when the above sulfur-containing phosphorus-based antiwear agent is used instead of (B) phosphorus-based antiwear agent, there is a decrease in sludge suppression, an increase in friction coefficient, and a decrease in cylinder squealing prevention due to this. It becomes easy to occur and the same effect as the lubricating oil composition of the present invention cannot be obtained.

  In addition, when a sulfur-containing phosphorus-based wear inhibitor is used in the presence of the components (A) to (C) according to the present invention, the sludge suppression property may be deteriorated. The content is preferably 5% by mass or less, more preferably 1% by mass or less, even more preferably 0.1% by mass or less, and more preferably 0.1% by mass or less, based on the total amount of the composition. Most preferably, it contains no inhibitor.

  The lubricating oil composition of the present invention may further contain a sulfur-based antiwear agent in addition to (B) the phosphorus-based antiwear agent. Examples of the sulfur-based antiwear agent include dihydrocarbyl polysulfide, sulfide ester, sulfide mineral oil, zinc dithiocarbamate compound, molybdenum dithiophosphate, and molybdenum dithiocarbamate.

  However, the use of a sulfur-based antiwear agent causes a decrease in sludge suppression, an increase in friction coefficient, and a decrease in cylinder squeal prevention. Therefore, the addition amount of the sulfur-based antiwear agent is preferably 5% by mass or less, more preferably 1% by mass or less, and further preferably 0.5% by mass or less, based on the total amount of the composition. More preferably, most not added.

［式中、Ｒ^１５は水素原子又はメチル基を示し、Ｒ^１６は炭素数１〜１８のアルキル基を示す。］

［式中、Ｒ^１７は水素原子又はメチル基を示し、Ｒ^１８は炭素数１〜１２の炭化水素基を示す。］

［式中、Ｙ^１及びＹ^２は同一でも異なっていてもよく、それぞれ水素原子、炭素数１〜１８のアルコキシ基、又は炭素数１〜１８のモノアルキルアミノ基を示す。］

［式中、Ｒ^１９は水素原子又はメチル基を示し、Ｒ^２０は炭素数２〜１８のアルキレン基を示し、ａは０又は１を示し、Ｙ^３は窒素原子を含有する炭素数１〜３０の有機基を示す。］

［式中、Ｒ^２１は水素原子又はメチル基を示し、Ｙ^４は窒素原子を含有する炭素数１〜３０の有機基を示す。］ (C) As the dispersion-type viscosity index improver, any compound used as a dispersion-type viscosity index improver for lubricating oil can be used. For example, a nitrogen-containing monomer having an ethylenically unsaturated bond is a copolymerization component. The copolymer containing as is preferable. More specifically, one or more monomers selected from the compounds represented by the following general formula (8), (9) or (10) (hereinafter referred to as “monomer (C-1)”); The copolymer with the 1 type (s) or 2 or more types of monomer (henceforth "monomer (C-2)") chosen from the compound represented by the following general formula (11) or (12) is preferable.

[Wherein, R ¹⁵ represents a hydrogen atom or a methyl group, and R ¹⁶ represents an alkyl group having 1 to 18 carbon atoms. ]

[Wherein, R ¹⁷ represents a hydrogen atom or a methyl group, and R ¹⁸ represents a hydrocarbon group having 1 to 12 carbon atoms. ]

[Wherein Y ¹ and Y ² may be the same or different and each represents a hydrogen atom, an alkoxy group having 1 to 18 carbon atoms, or a monoalkylamino group having 1 to 18 carbon atoms. ]

[Wherein, R ¹⁹ represents a hydrogen atom or a methyl group, R ²⁰ represents an alkylene group having 2 to 18 carbon atoms, a represents 0 or 1, and Y ³ represents 1 to 30 carbon atoms containing a nitrogen atom. An organic group of ]

[Wherein, R ²¹ represents a hydrogen atom or a methyl group, and Y ⁴ represents a C 1-30 organic group containing a nitrogen atom. ]

Specific examples of the alkyl group having 1 to 18 carbon atoms represented by R ¹⁶ in the general formula (8) include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, and octyl. Group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, etc. alkyl groups (these alkyl groups may be linear or branched) Is mentioned.

Specific examples of the hydrocarbon group having 1 to 12 carbon atoms represented by R ¹⁸ in the general formula (9) include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, Alkyl groups such as octyl, nonyl, decyl, undecyl, dodecyl (these alkyl groups may be linear or branched); butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl Groups, decenyl groups, undecenyl groups, dodecenyl groups and the like (these alkenyl groups may be linear or branched); C5-C7 cycloalkyl groups such as cyclopentyl, cyclohexyl, and cycloheptyl Methylcyclopentyl group, dimethylcyclopentyl group, methylethylcyclopentyl group, diethylcyclopentyl group, methylcyclo Alkylcycloalkyl groups having 6 to 11 carbon atoms such as cyclohexyl, dimethylcyclohexyl, methylethylcyclohexyl, diethylcyclohexyl, methylcycloheptyl, dimethylcycloheptyl, methylethylcycloheptyl, and diethylcycloheptyl groups (alkyl The group may be linear or branched, and the bonding position to the cycloalkyl group is also arbitrary); aryl group such as phenyl group, naphthyl group; tolyl group, xylyl group, ethylphenyl group, propylphenyl group Each alkylaryl group having 7 to 12 carbon atoms such as butylphenyl group, pentylphenyl group, hexylphenyl group (the alkyl group may be linear or branched, and the bonding position to the aryl group is arbitrary) ); Benzyl group, phenylethyl group, phenylpropyl group, C7-12 arylalkyl groups such as an phenylbutyl group, a phenylpentyl group, a phenylhexyl group (the alkyl group may be linear or branched, and the bonding position of the aryl group to the alkyl group is arbitrary) Etc.

The alkoxy group having 1 to 18 carbon atoms represented by Y ¹ and Y ² in the general formula (10) is a residue obtained by removing a hydrogen atom from a hydroxyl group of an alkyl alcohol having 1 to 18 carbon atoms (—OR ²² ; R ²² Is an alkyl group having 1 to 18 carbon atoms. The alkyl group having 1 to 18 carbon atoms represented by R ^22, include the exemplified alkyl group in the description of the alkyl group having 1 to 18 carbon atoms represented by R ¹⁶ in the general formula (8).

The monoalkylamino group having 1 to 18 carbon atoms represented by Y ¹ and Y ² in the general formula (10) is a residue (—NHR) obtained by removing a hydrogen atom from the amino group of a monoalkylamine having 1 to 18 carbon atoms. ^{23; R 23} is an alkyl group) having 1 to 18 carbon atoms. The alkyl group having 1 to 18 carbon atoms denoted by R ^23, include the exemplified alkyl group in the description of the alkyl group having 1 to 18 carbon atoms represented by R ¹⁶ in the general formula (8).

Specific examples of the alkylene group having 2 to 18 carbon atoms represented by R ²⁰ in the general formula (11) include ethylene group, propylene group, butylene group, pentylene group, hexylene group, heptylene group, octylene group, Nonylene group, decylene group, undecylene group, dodecylene group, tridecylene group, tetradecylene group, pentadecylene group, hexadecylene group, heptadecylene group, octadecylene group and other alkylene groups (these alkylene groups may be linear or branched), etc. Can be mentioned.

The organic group represented by Y ³ and Y ⁴ is preferably a group further containing an oxygen atom, and is preferably a group having a ring. In particular, it is preferable that the organic groups represented by Y ³ and Y ⁴ have a ring containing an oxygen atom from the viewpoint of sludge suppression, wear resistance, and friction characteristics. Further, when the organic group represented by Y ³ and Y ⁴ is a group having a ring, the ring may be either an aliphatic ring or an aromatic ring, but is preferably an aliphatic ring. Furthermore, the ring of the organic group represented by Y ³ and Y ⁴ is preferably a 6-membered ring from the viewpoints of sludge suppression, wear resistance, and friction characteristics.

Specific examples of the organic group represented by Y ³ and Y ⁴ include a dimethylamino group, a diethylamino group, a dipropylamino group, a dibutylamino group, an anilino group, a toluidino group, a xylidino group, an acetylamino group, and a benzoylamino group. Morpholino group, pyrrolyl group, pyrrolino group, pyridyl group, methylpyridyl group, pyrrolidinyl group, piperidinyl group, quinonyl group, pyrrolidonyl group, pyrrolidono group, imidazolino group, pyrazino group, etc., among which morpholino group is particularly preferable .

  Preferred examples of the compounds represented by the general formulas (8) to (10) include alkyl acrylates having 1 to 18 carbon atoms, alkyl methacrylates having 1 to 18 carbon atoms, olefins having 2 to 20 carbon atoms, styrene, Examples thereof include methylstyrene, maleic anhydride ester, maleic anhydride amide, and a mixture thereof.

  Preferred examples of the compound represented by the general formula (11) or (12) include dimethylaminomethyl methacrylate, diethylaminomethyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, 2-methyl-5-vinylpyridine, Examples include morpholinomethyl methacrylate, morpholinoethyl methacrylate, N-vinylpyrrolidone, and mixtures thereof.

  Among the compounds represented by the general formulas (8) to (10), the compound represented by the general formula (8) is preferable as the monomer (C-1) from the viewpoint of low-temperature performance. On the other hand, the monomer (C-2) is represented by the general formula (11) among the compounds represented by the general formula (11) or (12) in terms of sludge suppression, wear resistance, and friction characteristics. Are preferred.

  When the monomer (C-1) and the monomer (C-2) are copolymerized, the polymerization ratio (molar ratio) between the monomer (C-1) and the monomer (C-2) is arbitrary, but 80:20 It is preferable to be within the range of ~ 95: 5. The reaction method of the copolymerization is also arbitrary. Usually, the monomer (C-1) and the monomer (C-2) are subjected to radical solution polymerization in the presence of a polymerization initiator such as benzoyl peroxide. This copolymer can be obtained easily and reliably. Although the number average molecular weight of the copolymer obtained is also arbitrary, Preferably it is 1,000-1,500,000, More preferably, it is 10,000-200,000.

  The content of (C) the dispersion type viscosity index improver is preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 2% by mass or less, based on the total amount of the composition. Even if the content exceeds 10% by mass, no further improvement in sludge suppression, wear resistance and frictional properties commensurate with the content is observed, and viscosity reduction due to shear tends to occur. The content of the (C) dispersion type viscosity index improver is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and further preferably 0.1% by mass or more, based on the total amount of the composition. It is. When content is less than 0.01 mass%, it exists in the tendency for sludge suppression property, abrasion resistance, or a friction characteristic to fall.

  The lubricating oil composition of the present invention may comprise the above base oil, (A) a phosphorus-containing carboxylic acid compound, (B) a phosphorus-based antiwear agent, and (C) a dispersion-type viscosity index improver. However, it is preferable to further contain (D) an oily agent from the viewpoint of further improving the cylinder squealing prevention property (stick slip prevention property).

  (D) As oily agent, ester oily agent, alcohol oily agent, carboxylic acid oily agent, ether oily agent, amine oily agent, amide oily agent, etc. are mentioned.

  The ester oily agent is obtained by reacting an alcohol and a carboxylic acid. The alcohol may be a monohydric alcohol or a polyhydric alcohol. The carboxylic acid may be a monobasic acid or a polybasic acid.

  As the monohydric alcohol constituting the ester oil-based agent, those having 1 to 24 carbon atoms, preferably 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms are usually used. May be saturated, saturated or unsaturated. Specific examples of the alcohol having 1 to 24 carbon atoms include methanol, ethanol, linear or branched propanol, linear or branched butanol, linear or branched pentanol, and linear Linear or branched hexanol, linear or branched heptanol, linear or branched octanol, linear or branched nonanol, linear or branched decanol, linear or branched Undecanol, linear or branched dodecanol, linear or branched tridecanol, linear or branched tetradecanol, linear or branched pentadecanol, linear or branched hexadecane Decanol, linear or branched heptadecanol, linear or branched octadecanol, linear or branched nonadecanol, linear or branched icosa Lumpur, linear or branched Hen'ikosanoru, linear or branched Torikosanoru, such as linear or branched tetracosanol, and mixtures thereof.

  Moreover, as a polyhydric alcohol which comprises ester oiliness agent, a 2-10 valence is used normally, Preferably a 2-6 valence is used. Specific examples of the 2 to 10 polyhydric alcohol include, for example, ethylene glycol, diethylene glycol, polyethylene glycol (3 to 15 mer of ethylene glycol), propylene glycol, dipropylene glycol, and polypropylene glycol (3 to 15 of propylene glycol). Monomer), 1,3-propanediol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,2-propanediol, 2-methyl-1,3 -Dihydric alcohols such as propanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, neopentylglycol; glycerin, polyglycerin (glycerin 2- Octamers such as diglycerin, triglyceride Phosphorus, tetraglycerin, etc.), trimethylolalkanes (trimethylolethane, trimethylolpropane, trimethylolbutane, etc.) and their 2- to 8-mer, pentaerythritol and their 2- to 4-mer, 1,2,4- Butanetriol, 1,3,5-pentanetriol, 1,2,6-hexanetriol, 1,2,3,4-butanetetrol, sorbitol, sorbitan, sorbitol glycerin condensate, adonitol, arabitol, xylitol, mannitol, etc. Polyhydric alcohols; sugars such as xylose, arabinose, ribose, rhamnose, glucose, fructose, galactose, mannose, sorbose, cellobiose, maltose, isomaltose, trehalose, sucrose, and mixtures thereof That.

  Among these polyhydric alcohols, ethylene glycol, diethylene glycol, polyethylene glycol (ethylene glycol 3-10 mer), propylene glycol, dipropylene glycol, polypropylene glycol (propylene glycol 3-10 mer), 1,3- Propanediol, 2-methyl-1,2-propanediol, 2-methyl-1,3-propanediol, neopentyl glycol, glycerin, diglycerin, triglycerin, trimethylolalkane (trimethylolethane, trimethylolpropane, trimethylol Methylol butane and the like, and dimers and tetramers thereof, pentaerythritol, dipentaerythritol, 1,2,4-butanetriol, 1,3,5-pentanetriol, 1,2,6-hexanetriol , 1,2,3,4 butane tetrol, sorbitol, sorbitan, sorbitol glycerin condensate, adonitol, arabitol, xylitol, divalent to hexavalent polyhydric alcohols and mixtures thereof, such as mannitol and the like are preferable. Furthermore, ethylene glycol, propylene glycol, neopentyl glycol, glycerin, trimethylol ethane, trimethylol propane, pentaerythritol, sorbitan, and a mixture thereof are more preferable because they are more excellent in preventing cylinder squealing.

  The alcohol constituting the ester oily agent may be a monohydric alcohol or a polyhydric alcohol as described above, but is preferably a polyhydric alcohol from the viewpoint of excellent cylinder squealing prevention properties.

  Of the acids constituting the ester oily agent, as the monobasic acid, a fatty acid having 1 to 24 carbon atoms is usually used, and the fatty acid may be linear or branched, and may not be saturated. It may be saturated. Specifically, for example, formic acid, acetic acid, propionic acid, linear or branched butanoic acid, linear or branched pentanoic acid, linear or branched hexanoic acid, linear or branched Heptanoic acid, linear or branched octanoic acid, linear or branched nonanoic acid, linear or branched decanoic acid, linear or branched undecanoic acid, linear or branched Dodecanoic acid, linear or branched tridecanoic acid, linear or branched tetradecanoic acid, linear or branched pentadecanoic acid, linear or branched hexadecanoic acid, linear or branched Heptadecanoic acid, linear or branched octadecanoic acid, linear or branched hydroxyoctadecanoic acid, linear or branched nonadecanoic acid, linear or branched icosanoic acid, linear or branched Henicosanoic acid, linear or minute Docosanoic acid, linear or branched tricosanoic acid, saturated fatty acids such as linear or branched tetracosanoic acid, acrylic acid, linear or branched butenoic acid, linear or branched pentene Acid, linear or branched hexenoic acid, linear or branched heptenoic acid, linear or branched octenoic acid, linear or branched nonenoic acid, linear or branched decene Acid, linear or branched undecenoic acid, linear or branched dodecenoic acid, linear or branched tridecenoic acid, linear or branched tetradecenoic acid, linear or branched pentadecene Acid, linear or branched hexadecenoic acid, linear or branched heptadecenoic acid, linear or branched octadecenoic acid, linear or branched hydroxyoctadecenoic acid, linear or branched Nonadecenoic acid, linear or minute Unsaturated fatty acids such as linear icosenoic acid, linear or branched henicosenoic acid, linear or branched docosenoic acid, linear or branched tricosenoic acid, linear or branched tetracosenoic acid, And mixtures thereof.

  Examples of the polybasic acid include dibasic acid and trimellitic acid, and dibasic acid is preferable. The dibasic acid may be a chain dibasic acid or a cyclic dibasic acid. Further, in the case of a chain dibasic acid, it may be either linear or branched, and may be either saturated or unsaturated. The chain dibasic acid is preferably a chain dibasic acid having 2 to 16 carbon atoms. Specifically, for example, ethanedioic acid, propanedioic acid, linear or branched butanedioic acid, linear Or branched pentanedioic acid, linear or branched hexanedioic acid, linear or branched heptanedioic acid, linear or branched octanedioic acid, linear or branched nonane diacid Acid, linear or branched decanedioic acid, linear or branched undecanedioic acid, linear or branched dodecanedioic acid, linear or branched tridecanedioic acid, linear or Branched tetradecanedioic acid, linear or branched heptadecanedioic acid, linear or branched hexadecanedioic acid, linear or branched hexenedioic acid, linear or branched heptenedioic acid Linear or branched octene diacid, linear or branched nonene diacid, linear or branched Branched decenedioic acid, linear or branched undecenedioic acid, linear or branched dodecenedioic acid, linear or branched tridecenedioic acid, linear or branched tetradecenedioic acid And linear or branched heptacene diacid, linear or branched hexadecene diacid, and mixtures thereof. Examples of the cyclic dibasic acid include 1,2-cyclohexanedicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, and aromatic dicarboxylic acid. Among these, a chain dibasic acid is preferable from the viewpoint of stability.

  The acid constituting the ester oil-based agent may be a monobasic acid or a polybasic acid as described above, but a monobasic acid is preferred from the viewpoint of preventing cylinder squealing.

The combination of the alcohol and the acid in the ester oily agent is arbitrary and is not particularly limited, and examples thereof include esters by the following combinations (i) to (vii).
(I) ester of monohydric alcohol and monobasic acid (ii) ester of polyhydric alcohol and monobasic acid (iii) ester of monohydric alcohol and polybasic acid (iv) polyhydric alcohol and polybasic acid Ester (v) monohydric alcohol, mixture of polyhydric alcohol and polybasic acid (vi) mixed ester of polyhydric alcohol with monobasic acid, polybasic acid (vii) monohydric alcohol A mixed ester of a mixture of a polyhydric alcohol and a monobasic acid or polybasic acid.

  Each of the esters (ii) to (vii) may be a complete ester in which all of the hydroxyl groups of the polyhydric alcohol or the carboxyl groups of the polybasic acid are esterified, and some of them are hydroxyl groups or carboxyl groups. The remaining partial ester may be used.

  Among the esters (i) to (vii) above, (ii) an ester of a polyhydric alcohol and a monobasic acid is preferable. Such an ester has a very high effect of improving the cylinder noise.

  The ester of (ii) may be a complete ester in which all of the hydroxyl groups of the polyhydric alcohol are esterified, or may be a partial ester in which a portion remains as a hydroxyl group. Complete esters are preferable from the viewpoint of precipitation prevention, and partial esters are preferable from the viewpoint of friction characteristics.

  Furthermore, when the ester of (ii) contains a partial ester, the partial ester is a combination of two or more types of partial esters having different degrees of esterification from the standpoints of precipitation prevention, friction characteristics, wear resistance, and rust prevention. It is preferably a mixture, and more preferably a mixture of a partial ester having a degree of esterification of 1 and a partial ester having a degree of esterification of 2 or more. The degree of esterification here means the number of ester bonds in one molecule. For example, when the polyhydric alcohol constituting the ester of (ii) is sorbitan, the partial ester having a degree of esterification of 1 is a sorbitan monoester, while the partial ester having a degree of esterification of 2 or more Sorbitan diesters and sorbitan triesters are included.

  Furthermore, when the ester of (ii) includes both a partial ester having a degree of esterification of 1 and a partial ester having a degree of esterification of 2 or more, the ratio of the partial ester having a degree of esterification of 1 is Based on the total amount of the two, it is preferably 10 to 70 mol%, more preferably 20 to 50 mol%. Moreover, the ratio of the partial ester whose esterification degree is 2 or more is preferably 30 to 70 mol%, more preferably 50 to 80 mol%, based on the total amount of both.

  Further, the monobasic acid constituting the ester of (ii) may be either a straight chain fatty acid or a branched fatty acid, but a straight chain fatty acid is preferable from the viewpoint of frictional properties, and the precipitation preventing property Is preferably a branched fatty acid.

  The monobasic acid constituting the ester of (ii) may be either a saturated fatty acid or an unsaturated fatty acid, but is preferably a saturated fatty acid from the viewpoint of friction characteristics and wear resistance, and prevents precipitation. From the viewpoint of sex, unsaturated fatty acids are preferred. Furthermore, when the monobasic acid contains both saturated fatty acid and unsaturated fatty acid, the ratio of the saturated fatty acid to the total of both is preferably 60 mol% or more from the viewpoint of friction characteristics (particularly reduction of the friction coefficient), More preferably, it is 75 mol% or more, More preferably, it is 90 mol% or more, More preferably, it is 95 mol% or more.

  Further, the carbon number of the monobasic acid constituting the ester of (ii) is not particularly limited, but from the viewpoint of precipitation prevention, a short-chain fatty acid having 1 to 4 carbon atoms, more preferably 2 carbon atoms, and carbon It is preferable to combine with a long chain fatty acid of several 10 to 24, more preferably 12 to 18 carbon atoms. Furthermore, when combining said short chain fatty acid and long chain fatty acid, the ratio of the short chain fatty acid to the sum total of both becomes like this. Preferably it is 50-80 mol%, More preferably, it is 60-75 mol%, More preferably, it is 65-65. 70 mol%.

Among the esters of the above (ii), it is preferable to use the esters shown in the following (ii-1) to (ii-4) from the viewpoint that various properties such as friction properties and precipitation preventing properties can be achieved in a balanced manner.
(Ii-1) Monoester of polyhydric alcohol and unsaturated fatty acid (ii-2) An ester of polyhydric alcohol and unsaturated fatty acid, the partial ester having a degree of esterification of 1 and the degree of esterification of 2 The ester (ii-3) containing both the partial ester and the complete ester of a polyhydric alcohol and a fatty acid, wherein the constituent fatty acid is a short chain fatty acid having 1 to 4 carbon atoms and a long chain having 10 to 24 carbon atoms Ester containing both fatty acids (ii-4) An ester of a polyhydric alcohol and a branched saturated fatty acid, including both a partial ester having a degree of esterification of 1 and a partial ester having a degree of esterification of 2 or more ester.

  The ester of (ii-1) is preferable in that the friction characteristics and the precipitation preventing property can be achieved at a high level. The number of carbon atoms of the unsaturated fatty acid constituting the ester (ii-1) is preferably 10 or more, more preferably 12 or more, and still more preferably 14 or more, from the viewpoint that the anti-cylinder property is further improved. In addition, the number of carbon atoms of the unsaturated fatty acid is preferably 28 or less, more preferably 26 or less, and still more preferably 24 or less, from the viewpoint of precipitation prevention. Examples of such esters include glycerin monooleate and sorbitan monooleate.

  The ester (ii-2) is preferable in that it can achieve all of friction characteristics (particularly cylinder squeal prevention), precipitation prevention, wear resistance, and rust prevention in a high level with a good balance. The polyhydric alcohol constituting the ester of (ii-2) may be one kind or a mixture of two or more kinds. However, when the polyhydric alcohol contains a divalent alcohol, a polyvalent alcohol having a valence of 3 or more. It is necessary to further contain a monohydric alcohol.

  In the ester of (ii-2), the ratio of the partial ester having an esterification degree of 1 is based on the total amount of the partial ester having an esterification degree of 1 and the partial ester having an esterification degree of 2 or more. , Preferably it is 10-70 mol%, More preferably, it is 20-50 mol%. The proportion of the partial ester having an esterification degree of 2 or more is preferably 30 to 70 mol based on the total amount of the partial ester having an esterification degree of 1 and the partial ester having an esterification degree of 2 or more. %, More preferably 50 to 80 mol%. The ester of (ii-2) may further contain a complete ester, but all of friction characteristics (particularly cylinder squealing prevention), precipitation prevention, wear resistance and rust prevention are at a high level. From the viewpoint of achieving a good balance, the content of the complete ester is preferably 10 mol% or less, more preferably 5 mol% or less, based on the total amount of the ester (ii-2), and (ii) It is particularly preferred that the ester of -2) does not contain a complete ester.

  The ester (ii-3) is preferable in that it can achieve all of friction characteristics (particularly, reduction of friction coefficient and energy saving), precipitation prevention and wear resistance at a high level in a well-balanced manner. In the ester of (ii-3), it is preferable to combine a short-chain fatty acid having 2 carbon atoms and a long-chain fatty acid having 12 to 18 carbon atoms from the viewpoint that the precipitation preventing property can be further improved. Moreover, the ratio of the short chain fatty acid to the total amount of the constituent fatty acid is preferably 60 to 80 mol%, more preferably 60 to 75 mol%, still more preferably 65 to 70 mol%. Furthermore, from the viewpoint of further improving the friction characteristics (particularly reduction of the friction coefficient), the ratio of the saturated fatty acid to the total amount of the constituent fatty acids is preferably 60 mol% or more, more preferably 75 mol% or more, and still more preferably 90 mol. % Or more, more preferably 95 mol% or more.

  The partial ester (ii-4) is preferable in that it can achieve all of friction characteristics, precipitation prevention, wear resistance, and rust prevention at a high level in a well-balanced manner. In addition, the polyhydric alcohol constituting the ester of (ii-4) may be one kind or a mixture of two or more kinds. However, when the polyhydric alcohol contains a divalent alcohol, a polyvalent alcohol having a valence of 3 or more. It is necessary to further contain a monohydric alcohol.

  In the partial ester (ii-4) above, the ratio of the partial ester having an esterification degree of 1 is based on the total amount of the partial ester having an esterification degree of 1 and the partial ester having an esterification degree of 2 or more. As, it is preferably 10 to 70 mol%, more preferably 20 to 50 mol%. The proportion of the partial ester having an esterification degree of 2 or more is preferably 30 to 70 mol based on the total amount of the partial ester having an esterification degree of 1 and the partial ester having an esterification degree of 2 or more. %, More preferably 50 to 80 mol%. In addition, although the ester of (ii-4) may further contain a complete ester, all of friction characteristics (particularly cylinder squealing prevention), precipitation prevention, wear resistance and rust prevention are all at a high level. From the viewpoint of achieving a good balance, the content of the complete ester is preferably 10 mol% or less, more preferably 5 mol% or less, based on the total amount of the ester (ii-4), and (ii) It is particularly preferred that the ester of -4) does not contain a complete ester.

  Among the esters of (ii-1) to (ii-4) above, the balance of friction characteristics, precipitation prevention and wear resistance is the best, and also excellent in rust prevention, so that (ii-2) The esters are particularly preferred.

  Examples of the alcohol oil-based agent include alcohols exemplified in the description of the ester oil-based agent. The number of carbon atoms in the alcohol oil-based agent is preferably 6 or more, more preferably 8 or more, and most preferably 10 or more, from the viewpoint of improving cylinder squealing prevention. Moreover, since there exists a possibility that it may precipitate easily when carbon number is too large, 24 or less are preferable, 20 or less are more preferable, and 18 or less are the most preferable.

  The carboxylic acid oily agent may be a monobasic acid or a polybasic acid. Examples of such carboxylic acids include monobasic acids and polybasic acids exemplified in the description of the ester oily agent. Among these, monobasic acids are preferable from the viewpoint of improving the prevention of cylinder squealing. In addition, the number of carbon atoms of the carboxylic acid oil-based agent is preferably 6 or more, more preferably 8 or more, and most preferably 10 or more, from the viewpoint of improving cylinder squealing prevention. Moreover, since there exists a possibility that it may precipitate easily when carbon number of a carboxylic acid oiliness agent is too large, 24 or less are preferable, 20 or less are more preferable, and 18 or less are the most preferable.

  Examples of ether oily agents include etherified products of 3 to 6 aliphatic polyhydric alcohols, bimolecular condensates or trimolecular condensates of 3 to 6 aliphatic polyhydric alcohols, and the like.

［式中、Ｒ^２４〜Ｒ^４８は同一でも異なっていてもよく、それぞれ水素原子又は炭素数１〜１８の直鎖状もしくは分岐鎖状のアルキル基、アリル基、アラルキル基、−（Ｒ^ａＯ）_ｎ−Ｒ^ｂ（Ｒ^ａは炭素数２〜６のアルキレン基、Ｒ^ｂは炭素数１〜２０のアルキル基、アリル基、アラルキル基、ｎは１〜１０の整数を示す）で示されるグリコールエーテル残基を示す。］ The etherified product of a 3-6 valent aliphatic polyhydric alcohol is represented by the following general formulas (13)-(18), for example.

[Wherein R ^{24 to} R ⁴⁸ may be the same or different, and each represents a hydrogen atom or a linear or branched alkyl group having 1 to 18 carbon atoms, an allyl group, an aralkyl group, — (R ^a O ) _N- R ^b (R ^a is an alkylene group having 2 to 6 carbon atoms, R ^b is an alkyl group having 1 to 20 carbon atoms, an allyl group, an aralkyl group, and n is an integer of 1 to 10) Indicates an ether residue. ]

Specific examples of the 3-6 valent aliphatic polyhydric alcohol include glycerin, trimethylolpropane, erythritol, pentaerythritol, arabitol, sorbitol, mannitol and the like. R ^{24 to} R ⁴⁸ in the general formulas (13) to (18) are methyl group, ethyl group, n-propyl group, isopropyl group, various butyl groups, various pentyl groups, various hexyl groups, various heptyl groups, Various octyl groups, various nonyl groups, various decyl groups, various undecyl groups, various dodecyl groups, various tridecyl groups, various tetradecyl groups, various pentadecyl groups, various hexadecyl groups, various heptadecyl groups, various octadecyl groups, phenyl groups, benzyl groups, etc. Is mentioned. The etherified product also includes a partially etherified product in which a part of R ^{24 to} R ⁴⁸ is a hydrogen atom.

［式中、Ｒ^２４〜Ｒ^２６及びＲ^３４〜Ｒ^３７はそれぞれ式（１３）中のＲ^２４〜Ｒ^２６及び式（１６）中のＲ^３４〜Ｒ^３７と同一の定義内容を示す。］ The etherified product of a bimolecular condensate or a trimolecular condensate of a 3-6 valent aliphatic polyhydric alcohol is the same or different kind of condensate among the compounds represented by the general formulas (13) to (18). Is mentioned. For example, the bimolecular condensate of alcohol and the etherified product of trimolecular condensate represented by general formula (13) are represented by general formulas (19) and (20), respectively. Moreover, the etherified product of the alcohol bimolecular condensate and trimolecular condensate represented by the general formula (16) is represented by the general formulas (21) and (22), respectively.

^Wherein indicates the ^R 34 ^{to R 37} the same definition and R 24 ^{to R 26} and ^R 34 ^{to R 37} each formula (13) ^R 24 ^{to R 26} and the formula (16) in. ]

  Specific examples of bimolecular and trimolecular condensates of 3-6 valent aliphatic polyhydric alcohols include diglycerin, ditrimethylolpropane, dipentaerythritol, disorbitol, triglycerin, tritrimethylolpropane, tripentaerythritol. And trisorbitol.

  Specific examples of the ether oil agents represented by the general formulas (13) to (18) include trihexyl ether of glycerin, dimethyl octyl triether of glycerin, di (methyloxyisopropylene) dodecyl triether of glycerin, and glycerin. Diphenyl octyl triether, di (phenyloxy isopropylene) dodecyl triether of glycerol, trihexyl ether of trimethylol propane, dimethyl octyl triether of trimethylol propane, di (methyloxy isopropylene) dodecyl triether of trimethylol propane, Tetrahexyl ether of pentaerythritol, trimethyloctyl tetraether of pentaerythritol, tri (methyloxyisopropylene) dodecylte of pentaerythritol Laether, Hexapropyl ether of sorbitol, Tetramethyloctylpentaether of sorbitol, Hexa (methyloxyisopropylene) ether of sorbitol, Tetrabutyl ether of diglycerol, Dimethyldioctyltetraether of diglycerol, Tri (methyloxyisopropylene) ) Dodecyl tetraether, triglycerin pentaethyl ether, triglycerin trimethyldioctylpentaether, triglycerin tetra (methyloxyisopropylene) decylpentaether, ditrimethylolpropane tetrabutylether, ditrimethylolpropane dimethyldioctyltetraether, Tri (methyloxyisopropylene) dodecyltetrae of ditrimethylolpropane Ter, tritrimethylolpropane pentaethyl ether, tritrimethylolpropane trimethyldioctylpentaether, tritrimethylolpropane tetra (methyloxyisopropylene) decylpentaether, dipentaerythritol hexapropylether, dipentaerythritol pentamethyloctylhexa Ether, dipentaerythritol hexa (methyloxyisopropylene) ether, tripentaerythritol octapropyl ether, tripentaerythritol pentamethyloctyl hexaether, tripentaerythritol hexa (methyloxyisopropylene) ether, disorbitol octater Methyl dioctyl deca ether, disorbitol deca (methyloxyisopropylate) N) ether. Among these, diphenyl octyl triether of glycerin, di (methyloxyisopropylene) dodecyl triether of trimethylolpropane, tetrahexyl ether of pentaerythritol, hexapropyl ether of sorbitol, dimethyldioctyl tetraether of diglycerin, triglycerin Tetra (methyloxyisopropylene) decyl pentaether, hexapropyl ether of dipentaerythritol, and pentamethyloctyl hexaether of tripentaerythritol are preferred.

  Specific examples of monoamines include monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monopropylamine (including all isomers), dipropylamine (including all isomers), Propylamine (including all isomers), monobutylamine (including all isomers), dibutylamine (including all isomers), tributylamine (including all isomers), monopentylamine (all including all isomers) Including isomers), dipentylamine (including all isomers), tripentylamine (including all isomers), monohexylamine (including all isomers), dihexylamine (including all isomers) ), Monoheptylamine (including all isomers), diheptylamine (including all isomers) ), Monooctylamine (including all isomers), dioctylamine (including all isomers), monononylamine (including all isomers), monodecylamine (including all isomers), monoundecyl (Including all isomers), monododecylamine (including all isomers), monotridecylamine (including all isomers), monotetradecylamine (including all isomers), monopentadecyl Amine (including all isomers), monohexadecylamine (including all isomers), monoheptadecylamine (including all isomers), monooctadecylamine (including all isomers), mononona Decylamine (including all isomers), monoicosylamine (including all isomers), monohenicosylamine (including all isomers), monodocosyl Min (including all isomers), monotricosylamine (including all isomers), dimethyl (ethyl) amine, dimethyl (propyl) amine (including all isomers), dimethyl (butyl) amine (all Isomers), dimethyl (pentyl) amine (including all isomers), dimethyl (hexyl) amine (including all isomers), dimethyl (heptyl) amine (including all isomers), dimethyl ( Octyl) amine (including all isomers), dimethyl (nonyl) amine (including all isomers), dimethyl (decyl) amine (including all isomers), dimethyl (undecyl) amine (all isomers) ), Dimethyl (dodecyl) amine (including all isomers), dimethyl (tridecyl) amine (including all isomers), dimethyl (tetradecyl) ) Amine (including all isomers), dimethyl (pentadecyl) amine (including all isomers), dimethyl (hexadecyl) amine (including all isomers), dimethyl (heptadecyl) amine (all isomers) ), Dimethyl (octadecyl) amine (including all isomers), dimethyl (nonadecyl) amine (including all isomers), dimethyl (icosyl) amine (including all isomers), dimethyl (henicosyl) Alkylamines such as amines (including all isomers), dimethyl (tricosyl) amine (including all isomers);

Monovinylamine, divinylamine, trivinylamine, monopropenylamine (including all isomers), dipropenylamine (including all isomers), tripropenylamine (including all isomers), monobutenylamine (Including all isomers), dibutenylamine (including all isomers), tributenylamine (including all isomers), monopentenylamine (including all isomers), dipentenylamine (all isomers) ), Tripentenylamine (including all isomers), monohexenylamine (including all isomers), dihexenylamine (including all isomers), monoheptenylamine (all isomers) ), Diheptenylamine (including all isomers), monooctenylamine (including all isomers), dioctenylamine (Including all isomers), monononenylamine (including all isomers), monodecenylamine (including all isomers), monoundecenyl (including all isomers), monododecenylamine (Including all isomers), monotridecenylamine (including all isomers), monotetradecenylamine (including all isomers), monopentadecenylamine (including all isomers), Monohexadecenylamine (including all isomers), monoheptadecenylamine (including all isomers), monooctadecenylamine (including all isomers), monononadecenylamine (all isomers) ), Monoicosenylamine (including all isomers), monohenicocenylamine (including all isomers), monodocosenylamine (including all isomers), Trichoderma cell (including all isomers) cycloalkenyl amines alkenyl amines, such as;
Dimethyl (vinyl) amine, dimethyl (propenyl) amine (including all isomers), dimethyl (butenyl) amine (including all isomers), dimethyl (pentenyl) amine (including all isomers), dimethyl ( Hexenyl) amine (including all isomers), dimethyl (heptenyl) amine (including all isomers), dimethyl (octenyl) amine (including all isomers), dimethyl (nonenyl) amine (all isomers) ), Dimethyl (decenyl) amine (including all isomers), dimethyl (undecenyl) amine (including all isomers), dimethyl (dodecenyl) amine (including all isomers), dimethyl (tridecenyl) Amine (including all isomers), dimethyl (tetradecenyl) amine (including all isomers), dimethyl (pen Decenyl) amine (including all isomers), dimethyl (hexadecenyl) amine (including all isomers), dimethyl (heptadecenyl) amine (including all isomers), dimethyl (octadecenyl) amine (all isomers) ), Dimethyl (nonadecenyl) amine (including all isomers), dimethyl (icosenyl) amine (including all isomers), dimethyl (henicosenyl) amine (including all isomers), dimethyl (tricosenyl) Monoamines having alkyl and alkenyl groups such as amines (including all isomers);
Monobenzylamine, (1-phenyltyl) amine, (2-phenylethyl) amine (also known as monophenethylamine), dibenzylamine, bis (1-phenethyl) amine, bis (2-phenylethylene) amine (also known as diphenethylamine) Aromatic substituted alkylamines such as

  C5-C16 cycloalkylamines such as monocyclopentylamine, dicyclopentylamine, tricyclopentylamine, monocyclohexylamine, dicyclohexylamine, monocycloheptylamine, dicycloheptylamine;

Monoamines having an alkyl group and a cycloalkyl group, such as dimethyl (cyclopentyl) amine, dimethyl (cyclohexyl) amine, dimethyl (cycloheptyl) amine;
(Methylcyclopentyl) amine (including all substituted isomers), bis (methylcyclopentyl) amine (including all substituted isomers), (dimethylcyclopentyl) amine (including all substituted isomers), bis (dimethylcyclopentyl) ) Amine (including all substituted isomers), (ethylcyclopentyl) amine (including all substituted isomers), bis (ethylcyclopentyl) amine (including all substituted isomers), (methylethylcyclopentyl) amine ( All substituted isomers included), bis (methylethylcyclopentyl) amine (including all substituted isomers), (diethylcyclopentyl) amine (including all substituted isomers), (methylcyclohexyl) amine (all substituted isomers) Isomers), bis (methylcyclohexyl) amine (all substituted isomers) ), (Dimethylcyclohexyl) amine (including all substituted isomers), bis (dimethylcyclohexyl) amine (including all substituted isomers), (ethylcyclohexyl) amine (including all substituted isomers), bis (Ethylcyclohexyl) amine (including all substituted isomers), (Methylethylcyclohexyl) amine (including all substituted isomers), (Diethylcyclohexyl) amine (including all substituted isomers), (Methylcycloheptyl) ) Amine (including all substituted isomers), bis (methylcycloheptyl) amine (including all substituted isomers), (dimethylcycloheptyl) amine (including all substituted isomers), (ethylcycloheptylamine) (Including all substituted isomers), (methylethylcycloheptyl) amine (all substituted isomers) And alkyl cycloalkylamines such as (diethylcycloheptyl) amine (including all substituted isomers), etc. The monoamine also includes monoamines derived from fats and oils such as beef tallow amine. It is.

  Among the above-mentioned monoamines, alkylamine, monoamines having an alkyl group and an alkenyl group, monoamines having an alkyl group and a cycloalkyl group, cycloalkylamines and alkylcycloalkylamines are particularly preferable from the viewpoint of cylinder noise prevention, and alkylamines are preferred. And monoamines having an alkyl group and an alkenyl group are more preferred.

  Although there is no restriction | limiting in particular about carbon number of monoamine, From the point of cylinder squeal prevention property, it is preferable that it is 8 or more, and it is more preferable that it is 12 or more. Moreover, it is preferable that it is 24 or less from the point of the solubility to base oil, and it is more preferable that it is 18 or less.

  Furthermore, the number of hydrocarbon groups bonded to the nitrogen atom in the monoamine is not particularly limited, but is preferably 1 or 2 and more preferably 1 from the viewpoint of preventing cylinder noise.

  Amide oil-based agents include nitrogen-containing compounds such as amine compounds containing only fatty acids having 6 to 30 carbon atoms or acid chlorides thereof, ammonia, hydrocarbon groups having 1 to 8 carbon atoms or hydroxyl group-containing hydrocarbon groups in the molecule. And amides obtained by reacting.

  The fatty acid here may be a linear fatty acid or a branched fatty acid, and may be a saturated fatty acid or an unsaturated fatty acid. The carbon number is 6-30, preferably 9-24.

  Specific examples of the fatty acid include heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, Saturated fatty acids such as icosanoic acid, henicosanoic acid, docosanoic acid, tricosanoic acid, tetracosanoic acid, pentacosanoic acid, hexacosanoic acid, heptacosanoic acid, octacosanoic acid, nonacosanoic acid and triacontyl group (these saturated fatty acids may be linear or branched) ); Heptenoic acid, octenoic acid, nonenoic acid, decenoic acid, undecenoic acid, dodecenoic acid, tridecenoic acid, tetradecenoic acid, pentadecenoic acid, hexadecenoic acid, heptadecenoic acid, octadecenoic acid (including oleic acid), nonadecenoic acid, icosenic acid, Henicosenoic acid Unsaturated fatty acids such as docosenoic acid, tricosenoic acid, tetracosenoic acid, pentacosenoic acid, hexacosenoic acid, heptacosenoic acid, octacosenoic acid, nonacenoic acid, triacontenoic acid (these unsaturated fatty acids may be linear or branched, The position of the heavy bond is also arbitrary); but the linear fatty acids derived from lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, various fats and oils (coconut oil fatty acid etc.) A mixture of linear fatty acid and branched fatty acid synthesized by the oxo method or the like is preferably used.

  Specific examples of the nitrogen-containing compound to be reacted with the fatty acid include ammonia; monomethylamine, monoethylamine, monopropylamine, monobutylamine, monopentylamine, monohexylamine, monoheptylamine, monooctylamine, dimethylamine, Alkylamines such as methylethylamine, diethylamine, methylpropylamine, ethylpropylamine, dipropylamine, methylbutylamine, ethylbutylamine, propylbutylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, etc. May be chain or branched); monomethanolamine, monoethanolamine, monopropanolamine, monobutanolamine, monopentanolamine, monohexene Noramine, monoheptanolamine, monooctanolamine, monononanolamine, dimethanolamine, methanolethanolamine, diethanolamine, methanolpropanolamine, ethanolpropanolamine, dipropanolamine, methanolbutanolamine, ethanolbutanolamine, propanolbutanolamine, di Examples thereof include alkanolamines such as butanolamine, dipentanolamine, dihexanolamine, diheptanolamine and dioctanolamine (the alkanol group may be linear or branched); and mixtures thereof.

  Specific examples of fatty acid amides include lauric acid amide, lauric acid diethanolamide, lauric acid monopropanolamide, myristic acid amide, myristic acid diethanolamide, myristic acid monopropanolamide, palmitic acid amide, palmitic acid diethanolamide, and palmitic acid. Acid monopropanolamide, stearic acid amide, stearic acid diethanolamide, stearic acid monopropanolamide, oleic acid amide, oleic acid diethanolamide, oleic acid monopropanolamide, coconut oil fatty acid amide, coconut oil fatty acid diethanolamide, coconut oil fatty acid mono Propanolamide, C12-13 synthetic mixed fatty acid amide, C12-13 synthetic mixed fatty acid diethanolamide, C12-13 synthetic blend Fatty acid mono-propanol amides, and mixtures thereof are particularly preferred.

  As the oil-based agent (D) in the present invention, an ester oil-based agent (more preferably a polyhydric alcohol partial ester) and an amide oil-based agent are particularly preferable from the viewpoint of cylinder noise prevention.

  (D) Although content of oiliness agent is arbitrary, from the point which is excellent in the improvement effect of cylinder squealing prevention property, Preferably it is 0.01 mass% or more on the basis of the composition whole quantity, More preferably, it is 0.05 mass% As mentioned above, More preferably, it is 0.1 mass% or more. In addition, the content is preferably 10% by mass or less, more preferably 7.5% by mass or less, and further preferably 5% by mass or less, based on the total amount of the composition, from the viewpoint of precipitation prevention.

In addition, the lubricating oil composition of the present invention can further contain (E) an epoxy compound. (E) As an epoxy compound, the compound shown to the following (E-1)-(E-8) is mentioned.
(E-1) Phenyl glycidyl ether type epoxy compound (E-2) Alkyl glycidyl ether type epoxy compound (E-3) Glycidyl ester type epoxy compound (E-4) Allyl oxirane compound (E-5) Alkyl oxirane compound (E -6) Alicyclic epoxy compound (E-7) Epoxidized fatty acid monoester (E-8) Epoxidized vegetable oil.

  (E-1) Specific examples of the phenyl glycidyl ether type epoxy compound include phenyl glycidyl ether and alkylphenyl glycidyl ether. As used herein, the alkylphenyl glycidyl ether includes those having 1 to 3 alkyl groups having 1 to 13 carbon atoms, and those having one alkyl group having 4 to 10 carbon atoms, such as n-butylphenyl glycidyl. Ether, i-butylphenyl glycidyl ether, sec-butylphenyl glycidyl ether, tert-butylphenyl glycidyl ether, pentylphenyl glycidyl ether, hexylphenyl glycidyl ether, heptylphenyl glycidyl ether, octylphenyl glycidyl ether, nonylphenyl glycidyl ether, decylphenyl A glycidyl ether etc. can be illustrated as a preferable thing.

  (E-2) Specifically, as the alkyl glycidyl ether type epoxy compound, decyl glycidyl ether, undecyl glycidyl ether, dodecyl glycidyl ether, tridecyl glycidyl ether, tetradecyl glycidyl ether, 2-ethylhexyl glycidyl ether, neopentyl Examples include glycol diglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, 1,6-hexanediol diglycidyl ether, sorbitol polyglycidyl ether, polyalkylene glycol monoglycidyl ether, and polyalkylene glycol diglycidyl ether. .

［式中、Ｒ^４９は炭素数１〜１８の炭化水素基を表す］ (E-3) Specific examples of the glycidyl ester type epoxy compound include compounds represented by the following general formula (23).

[Wherein R ⁴⁹ represents a hydrocarbon group having 1 to 18 carbon atoms]

In the above formula (23), R ⁴⁹ represents a hydrocarbon group having 1 to 18 carbon atoms. Examples of such a hydrocarbon group include an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms, C5-C7 cycloalkyl group, C6-C18 alkylcycloalkyl group, C6-C10 aryl group, C7-C18 alkylaryl group, C7-C18 arylalkyl group, etc. Is mentioned. Among these, an alkylphenyl group having an alkyl group having 5 to 15 carbon atoms, an alkenyl group having 2 to 15 carbon atoms, a phenyl group, and an alkyl group having 1 to 4 carbon atoms is preferable.

  Among the glycidyl ester type epoxy compounds, preferred examples include glycidyl-2,2-dimethyloctanoate, glycidyl benzoate, glycidyl-tert-butyl benzoate, glycidyl acrylate, glycidyl methacrylate, and the like.

  Specific examples of the (E-4) allyloxirane compound include 1,2-epoxystyrene, alkyl-1,2-epoxystyrene, and the like.

  Specific examples of (E-5) alkyloxirane compounds include 1,2-epoxybutane, 1,2-epoxypentane, 1,2-epoxyhexane, 1,2-epoxyheptane, and 1,2-epoxyoctane. 1,2-epoxynonane, 1,2-epoxydecane, 1,2-epoxyundecane, 1,2-epoxydodecane, 1,2-epoxytridecane, 1,2-epoxytetradecane, 1,2-epoxypentadecane 1,2-epoxyhexadecane, 1,2-epoxyheptadecane, 1,1,2-epoxyoctadecane, 2-epoxynonadecane, 1,2-epoxyicosane and the like.

(E-6) As an alicyclic epoxy compound, the compound in which the carbon atom which comprises an epoxy group directly comprises the alicyclic ring like the compound represented by the following general formula (24) is mentioned. .

  (E-6) As the alicyclic epoxy compound, specifically, 1,2-epoxycyclohexane, 1,2-epoxycyclopentane, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, Bis (3,4-epoxycyclohexylmethyl) adipate, exo-2,3-epoxynorbornane, bis (3,4-epoxy-6-methylcyclohexylmethyl) adipate, 2- (7-oxabicyclo [4.1.0] ] Hept-3-yl) -spiro (1,3-dioxane-5,3 ′-[7] oxabicyclo [4.1.0] heptane, 4- (1′-methylepoxyethyl) -1,2- Examples thereof include epoxy-2-methylcyclohexane and 4-epoxyethyl-1,2-epoxycyclohexane.

  Specific examples of the (E-7) epoxidized fatty acid monoester include esters of epoxidized fatty acids having 12 to 20 carbon atoms with alcohols or phenols having 1 to 8 carbon atoms and alkylphenols. In particular, butyl, hexyl, benzyl, cyclohexyl, methoxyethyl, octyl, phenyl and butylphenyl esters of epoxy stearate are preferably used.

  Specific examples of (E-8) epoxidized vegetable oils include epoxy compounds of vegetable oils such as soybean oil, linseed oil, and cottonseed oil.

  Among these epoxy compounds, phenyl glycidyl ether type epoxy compounds, glycidyl ester type epoxy compounds, alicyclic epoxy compounds, and epoxidized fatty acid monoesters are preferable because glycidyl ether can be further improved in heat and hydrolysis stability. An ester type epoxy compound and an alicyclic epoxy compound are more preferable.

  (E) When the epoxy compound is contained in the lubricating oil composition of the present invention, the content is not particularly limited, but is preferably 0.1 to 5.0% by mass, more preferably 0.8%, based on the total amount of the composition. 2 to 2.0% by mass.

  Moreover, it is preferable that the lubricating oil composition of this invention further contains (F) phenolic antioxidant and / or (G) amine antioxidant from the point of oxidation stability and sludge suppression property.

［式中、Ｒ^５０は炭素数１〜４のアルキル基を示し、Ｒ^５１は水素原子又は炭素数１〜４のアルキル基を示し、Ｒ^５２は水素原子、炭素数１〜４のアルキル基、あるいは下記一般式（ｉ）又は（ｉｉ）で表される基を示す。

（式中、Ｒ^５３は炭素数１〜６のアルキレン基を示し、Ｒ^５４は炭素数１〜２４のアルキル基又はアルケニル基を示す。）

（式中、Ｒ^５５は炭素数１〜６のアルキレン基を示し、Ｒ^５６は炭素数１〜４のアルキル基を示し、Ｒ^５７は水素原子または炭素数１〜４のアルキル基を示す。）］

［式中、Ｒ^５８及びＲ^６２は同一でも異なっていてもよく、それぞれ炭素数１〜４のアルキル基を示し、Ｒ^５９及びＲ^６３は同一でも異なっていてもよく、それぞれ水素原子又は炭素数１〜４のアルキル基を示し、Ｒ^６０及びＲ^６１は同一でも異なっていてもよく、それぞれ炭素数１〜６のアルキレン基を示し、Ｘは炭素数１〜１８のアルキレン基又は下記一般式（ｉｉｉ）で表される基を示す。 As the (F) phenolic antioxidant, any phenolic compound used as an antioxidant for lubricating oils can be used, and although not particularly limited, the following general formula (25) or (26 The alkylphenol compound represented by this is preferable.

[Wherein, R ⁵⁰ represents an alkyl group having 1 to 4 carbon atoms, R ⁵¹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R ⁵² represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, Or the group represented by the following general formula (i) or (ii) is shown.

(In the formula, R ⁵³ represents an alkylene group having 1 to 6 carbon atoms, and R ⁵⁴ represents an alkyl group or alkenyl group having 1 to 24 carbon atoms.)

(In the formula, R ⁵⁵ represents an alkylene group having 1 to 6 carbon atoms, R ⁵⁶ represents an alkyl group having 1 to 4 carbon atoms, and R ⁵⁷ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.) ]

[Wherein, R ⁵⁸ and R ⁶² may be the same or different and each represents an alkyl group having 1 to 4 carbon atoms; R ⁵⁹ and R ⁶³ may be the same or different and each represents a hydrogen atom or a carbon number; 1 to 4 alkyl groups, R ⁶⁰ and R ^{61, which} may be the same or different, each represents an alkylene group having 1 to 6 carbon atoms, and X represents an alkylene group having 1 to 18 carbon atoms or the following general formula ( The group represented by iii) is shown.

—R ⁶⁴ —S—R ⁶⁵ — (iii)
(In the formula, R ⁶⁴ and R ⁶⁵ may be the same or different and each represents an alkylene group having 1 to 6 carbon atoms.)]

Specific examples of R ⁵⁰ in the general formula (25) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group. Although mentioned, a tert- butyl group is preferable from the point which is excellent in oxidation stability. Examples of R ⁵³ include a hydrogen atom or an alkyl group having 1 to 4 carbon atoms as described above, and a methyl group or a tert-butyl group is preferable from the viewpoint of excellent oxidation stability.

In the case where R ⁵² in the general formula (25) is an alkyl group having 1 to 4 carbon atoms, as R ⁵² , methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec -Butyl group, tert-butyl group and the like are mentioned, and from the viewpoint of excellent oxidation stability, a methyl group or an ethyl group is preferable.

Among the alkylphenol compounds represented by the general formula (25), 2,6-di-tert-butyl-p-cresol is particularly preferable as a compound when R ⁵² is an alkyl group having 1 to 4 carbon atoms. 2,6-di-tert-butyl-4-ethylphenol and mixtures thereof.

In the case where R ⁵² in the general formula (25) is a group represented by the general formula (i), the alkylene group having 1 to 6 carbon atoms represented by R ⁵³ in the general formula (i) is linear. However, it may be branched. Specifically, for example, methylene group, methylmethylene group, ethylene group (dimethylene group), ethylmethylene group, propylene group (methylethylene group), trimethylene group, straight chain or branched A butylene group, a linear or branched pentylene group, a linear or branched hexylene group, and the like.

R ⁵³ is an alkylene group having 1 to 2 carbon atoms, specifically, for example, a methylene group, a methylmethylene group, an ethylene group (dimethylene group), in that the compound represented by the general formula (25) can be produced by a reaction process with few. Etc. are more preferable.

On the other hand, the alkyl group or alkenyl group having 1 to 24 carbon atoms represented by R ⁵⁴ in the general formula (i) may be linear or branched, and specifically includes, for example, methyl group, ethyl group, propyl group. Group, 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, heptadecyl group, octadecyl group, nonadecyl group, Alkyl groups such as icosyl group, henocosyl group, docosyl group, tricosyl group, tetracosyl group (these alkyl groups may be linear or branched); vinyl group, propenyl group, isopropenyl group, butenyl group, pentenyl group Hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl Group, tridecenyl group, tetradecenyl group, pentadecenyl group, hexadecenyl group, heptadecenyl group, octadecenyl group, octadecadienyl group, nonadecenyl group, icocenyl group, henicosenyl group, alkenyl group such as dococenyl group, tricocenyl group, tetracocenyl group, etc. The alkenyl group may be linear or branched, and the position of the double bond is arbitrary).

R ⁵⁴ is an alkyl group having 4 to 18 carbon atoms, specifically, for example, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, because of its excellent solubility in base oil. Alkyl groups such as undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, and octadecyl group (these alkyl groups may be linear or branched), and have 6 carbon atoms. A linear or branched alkyl group having ˜12 is more preferable, and a branched alkyl group having 6 to 12 carbon atoms is particularly preferable.

Among the phenol compounds represented by the general formula (25), as a compound in the case where R ⁵² is a group represented by the general formula (i), R ⁵³ in the general formula (i) has 1 to 2 carbon atoms. R ⁵⁴ is more preferably a linear or branched alkyl group having 6 to 12 carbon atoms, and R ⁵³ in the general formula (i) is an alkylene group having 1 to 2 carbon atoms. R ⁵⁴ is particularly preferably a branched alkyl group having 6 to 12 carbon atoms.

  Specific examples of preferred compounds include (3-methyl-5-tert-butyl-4-hydroxyphenyl) acetate n-hexyl, (3-methyl-5-tert-butyl-4-hydroxyphenyl) isohexyl acetate, N-heptyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) acetate, isoheptyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) acetate, (3-methyl-5-tert-butyl) -4-hydroxyphenyl) acetic acid n-octyl, (3-methyl-5-tert-butyl-4-hydroxyphenyl) isooctyl acetate, (3-methyl-5-tert-butyl-4-hydroxyphenyl) acetic acid 2-ethylhexyl , (3-Methyl-5-tert-butyl-4-hydroxyphenyl) acetic acid n-nonyl (3-Methyl-5-tert-butyl-4-hydroxyphenyl) acetic acid isononyl, (3-methyl-5-tert-butyl-4-hydroxyphenyl) acetic acid n-decyl, (3-methyl-5-tert-butyl) -4-hydroxyphenyl) isodecyl acetate, (3-methyl-5-tert-butyl-4-hydroxyphenyl) acetate n-undecyl, (3-methyl-5-tert-butyl-4-hydroxyphenyl) isoundecyl acetate, 3-methyl-5-tert-butyl-4-hydroxyphenyl) acetate n-dodecyl, (3-methyl-5-tert-butyl-4-hydroxyphenyl) acetate isododecyl, (3-methyl-5-tert-butyl- 4-Hydroxyphenyl) propionate n-hexyl, (3-methyl-5-tert-butyl) 4-Hydroxyphenyl) isohexyl propionate, n-heptyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate, isoheptyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate N-octyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate, isooctyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate, (3-methyl-5- tert-butyl-4-hydroxyphenyl) 2-ethylhexyl propionate, n-nonyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate, (3-methyl-5-tert-butyl-4- Hydroxyphenyl) isononyl propionate, (3-methyl -5-tert-butyl-4-hydroxyphenyl) n-decyl propionate, isodecyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate, (3-methyl-5-tert-butyl-4 -Hydroxyphenyl) n-undecyl propionate, (3-methyl-5-tert-butyl-4-hydroxyphenyl) isoundecyl propionate, (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate n- Dodecyl, isododecyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate, (3,5-di-tert-butyl-4-hydroxyphenyl) acetate n-hexyl, (3,5-di-) tert-butyl-4-hydroxyphenyl) isohexyl acetate, (3,5-di- ert-Butyl-4-hydroxyphenyl) acetic acid n-heptyl, (3,5-di-tert-butyl-4-hydroxyphenyl) acetate isoheptyl, (3,5-di-tert-butyl-4-hydroxyphenyl) acetic acid n-octyl, (3,5-di-tert-butyl-4-hydroxyphenyl) isooctyl acetate, (3,5-di-tert-butyl-4-hydroxyphenyl) acetic acid 2-ethylhexyl, (3,5-di-) -Tert-butyl-4-hydroxyphenyl) acetic acid n-nonyl, (3,5-di-tert-butyl-4-hydroxyphenyl) acetic acid isononyl, (3,5-di-tert-butyl-4-hydroxyphenyl) N-decyl acetate, (3,5-di-tert-butyl-4-hydroxyphenyl) isodecyl acetate, (3,5-di-t rt-butyl-4-hydroxyphenyl) acetic acid n-undecyl, (3,5-di-tert-butyl-4-hydroxyphenyl) isoundecyl acetate, (3,5-di-tert-butyl-4-hydroxyphenyl) acetic acid n-dodecyl, (3,5-di-tert-butyl-4-hydroxyphenyl) isododecyl acetate, (3,5-di-tert-butyl-4-hydroxyphenyl) propionate n-hexyl, (3,5- Di-tert-butyl-4-hydroxyphenyl) isohexyl propionate, n-heptyl (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, (3,5-di-tert-butyl-4- Hydroxyphenyl) isoheptyl propionate, (3,5-di-tert-butyl-4-hydroxyphenyl) N-octyl propionate, (3,5-di-tert-butyl-4-hydroxyphenyl) isooctyl propionate, (3,5-di-tert-butyl-4-hydroxyphenyl) 2-ethylhexyl propionate, (3 , 5-Di-tert-butyl-4-hydroxyphenyl) n-nonyl propionate, (3,5-di-tert-butyl-4-hydroxyphenyl) isononyl propionate, (3,5-di-tert-butyl) -4-hydroxyphenyl) propionate n-decyl, (3,5-di-tert-butyl-4-hydroxyphenyl) isodecylpropionate, (3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid n-undecyl, (3,5-di-tert-butyl-4-hydroxyphenyl) propion Isoundecyl, n-dodecyl (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, isododecyl (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, and mixtures thereof Can be mentioned.

In the case where R ⁵² in the general formula (25) is a group represented by the general formula (ii), R ⁵⁵ in the general formula (ii) represents an alkylene group having 1 to 6 carbon atoms. The alkylene group may be linear or branched, and specific examples include various alkylene groups exemplified in the description of R ⁵³ above. R ⁵⁵ is an alkylene group having 1 to 3 carbon atoms, specifically, for example, a methylene group, a methylmethylene group, ethylene, because the compound of the general formula (25) can be produced in a reaction step with few reactions and its raw materials are easily available. A group (dimethylene group), ethylmethylene group, propylene group (methylethylene group), trimethylene group and the like are more preferable. Specific examples of R ⁵⁶ in the general formula (ii) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group. However, a tert-butyl group is preferable from the viewpoint of excellent oxidation stability. Examples of R ⁵⁷ include a hydrogen atom or an alkyl group having 1 to 4 carbon atoms as described above, and a methyl group or a tert-butyl group is preferable from the viewpoint of excellent oxidation stability.

Of the alkylphenol compounds represented by the general formula (25), specific examples of preferred compounds in the case where R ⁵² is a group represented by the general formula (ii) include bis (3,5- Di-tert-butyl-4-hydroxyphenyl) methane, 1,1-bis (3,5-di-tert-butyl-4-hydroxyphenyl) ethane, 1,2-bis (3,5-di-tert- Butyl-4-hydroxyphenyl) ethane, 1,1-bis (3,5-di-tert-butyl-4-hydroxyphenyl) propane, 1,2-bis (3,5-di-tert-butyl-4- Hydroxyphenyl) propane, 1,3-bis (3,5-di-tert-butyl-4-hydroxyphenyl) propane, 2,2-bis (3,5-di-tert-butyl-4-hydroxyphenyl) Nyl) propane, and mixtures thereof.

On the other hand, in the above general formula (26), R ⁵⁸ and R ⁶² may be the same or different and are each an alkyl group having 1 to 4 carbon atoms, specifically a methyl group, an ethyl group, or an n-propyl group. , An isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, and the like. From the viewpoint of excellent oxidation stability, both are preferably tert-butyl groups. R ⁵⁹ and R ⁶³ may be the same or different, and each includes a hydrogen atom or an alkyl group having 1 to 4 carbon atoms as described above. Or a tert-butyl group.

In addition, the alkylene group having 1 to 6 carbon atoms representing R ⁶⁰ and R ⁶¹ in the general formula (26) may be linear or branched, and specifically, each R individually. ^The various alkylene groups illustrated in description of ⁵³ are mentioned. R ⁶⁰ and R ⁶¹ are each independently an alkylene group having 1 to 2 carbon atoms, in that the compound represented by the general formula (26) can be produced by a reaction process with few compounds and the raw material is easily available. Specifically, for example, a methylene group, a methylmethylene group, an ethylene group (dimethylene group) and the like are more preferable.

In the general formula (26), the alkylene group having 1 to 18 carbon atoms represented by X is specifically, for example, a methylene group, a methylmethylene group, an ethylene group (dimethylene group), an ethylmethylene group, or a propylene group. (Methylethylene group), trimethylene group, butylene group, pentylene group, hexylene group, heptylene group, octylene group, nonylene group, decylene group, undecylene group, dodecylene group, tridecylene group, tetradecylene group, pentadecylene group, hexadecylene group, heptadecylene group , Octadecylene groups and the like (these alkylene groups may be linear or branched). From the viewpoint of easy availability of raw materials, an alkylene group having 1 to 6 carbon atoms, specifically, for example, a methylene group , Methylmethylene group, ethylene group (dimethylene group), ethylmethylene group, Pyrene group (methylethylene group), trimethylene group, butylene group, pentylene group, hexylene group and the like (these alkylene groups may be linear or branched) are more preferable, ethylene group (dimethylene group), trimethylene group, A linear alkylene group having 2 to 6 carbon atoms such as a linear butylene group (tetramethylene group, linear pentylene group (pentamethylene group), linear hexylene group (hexamethylene group), etc. is particularly preferred. Of the alkylphenol compounds represented, a compound represented by the following formula (27) is particularly preferred as a compound when X is an alkylene group having 1 to 18 carbon atoms.

In the case where X in the general formula (26) is a group represented by the general formula (iii), the alkylene group having 1 to 6 carbon atoms represented by R ⁶⁴ and R ⁶⁵ in the general formula (iii) is These may be linear or branched, and specific examples include various alkylene groups as described above for R ⁵³ individually. Since raw materials for producing the compound of the general formula (26) are easily available, R ⁶⁴ and R ⁶⁵ are each independently an alkylene group having 1 to 3 carbon atoms, specifically, for example, methylene group, methyl More preferred are methylene group, ethylene group (dimethylene group), ethylmethylene group, propylene group (methylethylene group), trimethylene group and the like. Of the alkylphenols represented by the general formula (26), a compound represented by the following formula (28) is particularly preferred as a compound when X is a group represented by the general formula (iii).

  Of course, as the component (F) of the present invention, one compound selected from alkylphenol compounds represented by the general formulas (25) and (26) may be used alone. Furthermore, a mixture or the like of any two or more compounds selected from the above may be used.

  (F) The content of the phenolic antioxidant is preferably 3% by mass or less, more preferably 2% by mass or less, and still more preferably 1% by mass or less, based on the total amount of the composition. Even if the content exceeds 3% by mass, oxidation stability sufficient to meet the content and further improvement of the sludge formation inhibiting effect are not seen, and the solubility in the base oil tends to decrease. On the other hand, the content of (F) phenolic antioxidant is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and further preferably 0.2% by mass or more, based on the total amount of the composition. is there. When the content is less than 0.01% by mass, the effect of improving the oxidation stability and sludge generation inhibiting property of the lubricating oil composition due to the addition tends to be insufficient.

［式中、Ｒ^６６は水素原子又は炭素数１〜１６のアルキル基を示す。］

［式中、Ｒ^６７及びＲ^６８は同一でも異なっていてもよく、それぞれ炭素数１〜１６のアルキル基を示す。］ In addition, as the (G) amine-based antioxidant, any amine-based compound used as an antioxidant for lubricating oils can be used, and is not particularly limited. For example, the following general formula (29 ) -Represented by phenyl-α-naphthylamine or p, p′-dialkyldiphenylamine represented by the following general formula (30), one or more aromatic amines are preferred.

[Wherein R ⁶⁶ represents a hydrogen atom or an alkyl group having 1 to 16 carbon atoms. ]

[Wherein, R ⁶⁷ and R ⁶⁸ may be the same or different and each represents an alkyl group having 1 to 16 carbon atoms. ]

In the above general formula (29) representing phenyl-α-naphthylamine, R ⁶⁶ represents a hydrogen atom or a linear or branched alkyl group having 1 to 16 carbon atoms. When the number of carbon atoms in R ⁶⁶ exceeds 16, the proportion of functional groups in the molecule becomes small, and the antioxidant ability may be weakened. Specific examples of the alkyl group for R ⁶⁶ include, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, A tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group and the like (these alkyl groups may be linear or branched).

Among the compounds represented by the general formula (29), when R ⁶⁶ is an alkyl group, a branched alkyl group having 8 to 16 carbon atoms is preferable because of its excellent solubility of the oxidation product itself in the base oil. Further, a branched alkyl group having 8 to 16 carbon atoms derived from an oligomer of an olefin having 3 or 4 carbon atoms is more preferable. Specific examples of the olefin having 3 or 4 carbon atoms include propylene, 1-butene, 2-butene and isobutylene, but from the viewpoint of excellent solubility of its own oxidation product in the base oil, Propylene or isobutylene is preferred.

When the phenyl-α-naphthylamine represented by the general formula (29) is used as the component (G) in the present invention, R ⁶⁶ represents a branched octyl group derived from a hydrogen molecule or a dimer of isobutylene, propylene Branched nonyl group derived from trimer, branched dodecyl group derived from isobutylene trimer, branched dodecyl group derived from propylene tetramer, or propylene pentamer Branched pentadecyl groups are particularly preferred, branched octyl groups derived from hydrogen molecules or dimers of isobutylene, branched dodecyl groups derived from isobutylene trimers or branched dodecyl derived from propylene tetramers The group is particularly preferred.

When Np-alkylphenyl-α-naphthylamine in which R ⁶⁶ is an alkyl group is used as the phenyl-α-naphthylamine represented by the general formula (29), as this Np-alkylphenyl-α-naphthylamine, A commercially available product may be used. In addition, phenyl-α-naphthylamine and a halogenated alkyl compound having 1 to 16 carbon atoms, an olefin having 2 to 16 carbon atoms, or an olefin oligomer having 2 to 16 carbon atoms and phenyl-α-naphthylamine using a Friedel-Crafts catalyst. It can be easily synthesized by reacting. Specific examples of Friedel-Crafts catalysts in this case include metal halides such as aluminum chloride, zinc chloride, and iron chloride; sulfuric acid, phosphoric acid, phosphorus pentoxide, boron fluoride, acidic clay, activated clay, etc. Or an acidic catalyst.

On the other hand, in the general formula (30) representing p, p′-dialkyldiphenylamine, R ⁶⁷ and R ⁶⁸ may be the same or different and each represents an alkyl group having 1 to 16 carbon atoms. When one or both of R ⁶⁷ and R ⁶⁸ are hydrogen atoms, they themselves may precipitate as sludge due to oxidation. On the other hand, when the number of carbon atoms exceeds 16, the proportion of functional groups in the molecule is small. Therefore, the antioxidant ability may be weakened.

Specific examples of R ⁶⁷ and R ⁶⁸ include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, A tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group and the like (these alkyl groups may be linear or branched). Among these, as R ¹⁸ and R ¹⁹ , a branched alkyl group having 3 to 16 carbon atoms is preferable from the viewpoint of excellent solubility of the oxidation product itself in the base oil, and further an olefin having 3 or 4 carbon atoms, Alternatively, a branched alkyl group having 3 to 16 carbon atoms derived from the oligomer is more preferable. Specific examples of the olefin having 3 or 4 carbon atoms include propylene, 1-butene, 2-butene, isobutylene, and the like, but the solubility of its own oxidation product in a lubricating base oil is excellent. From the viewpoint, propylene or isobutylene is preferable.

When the p, p′-dialkyldiphenylamine represented by the general formula (30) is used as the component (G) in the present invention, R ⁶⁷ and R ⁶⁸ are derived from an isopropyl group derived from propylene or isobutylene. tert-butyl group, branched hexyl group derived from propylene dimer, branched octyl group derived from isobutylene dimer, branched nonyl group derived from propylene trimer, isobutylene 3 A branched dodecyl group derived from a mer, a branched dodecyl group derived from a tetramer of propylene or a branched pentadecyl group derived from a pentamer of propylene is particularly preferred, and tert-butyl derived from isobutylene. A branched hexyl group derived from a dimer of propylene, a branched hexyl group derived from a dimer of isobutylene Butyl group, a branched nonyl group derived from propylene trimer, is a branched dodecyl group derived from a tetramer of a branched dodecyl or propylene derived from a trimer of isobutylene particularly preferred.

  A commercially available product may be used as the p, p'-dialkyldiphenylamine represented by the general formula (30). Further, similarly to the phenyl-α-naphthylamine represented by the general formula (29), diphenylamine and a halogenated alkyl compound having 1 to 16 carbon atoms, an olefin having 2 to 16 carbon atoms, an olefin having 2 to 16 carbon atoms, or these These oligomers and diphenylamine can be easily synthesized using a Friedel-Crafts catalyst. As the Friedel-Crafts catalyst at this time, specifically, for example, metal halides and acidic catalysts listed in the synthesis of phenyl-α-naphthylamine are used. As a matter of course, as the component (G) of the present invention, one compound selected from the aromatic amines represented by the general formulas (29) and (30) may be used alone. Furthermore, a mixture of two or more compounds selected from the above in an arbitrary mixing ratio may be used.

  (G) The content of the amine-based antioxidant is preferably 3% by mass or less, more preferably 2% by mass or less, and still more preferably 1% by mass or less, based on the total amount of the composition. Even if the content exceeds 3% by mass, no further improvement in oxidation stability and sludge generation inhibition sufficient for the content is observed, and the solubility in base oil tends to decrease. On the other hand, the content of the (G) amine-based antioxidant is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and further preferably 0.2% by mass or more, based on the total amount of the composition. is there. (G) When content of a component is less than 0.01 mass%, it exists in the tendency for the improvement effect of the oxidation stability and sludge production | generation suppression property by the addition to become inadequate.

  Moreover, the lubricating oil composition of the present invention can further contain (H) an organic acid metal salt.

  As such organic acid metal salts, sulfonates, phenates, salicylates, and mixtures thereof having alkali metals such as sodium and potassium, alkaline earth metals such as magnesium, calcium and barium as positive components are preferably used. Magnesium salts are particularly preferable from the viewpoint of improving the friction characteristics.

  The production method of the sulfonate used in the present invention is not particularly limited. For example, alkyl aromatic sulfonic acid alkali metal salts, alkaline earth metal salts and mixtures thereof obtained by sulfonating alkyl aromatic compounds having a molecular weight of 100 to 1500 (preferably 200 to 700) are preferably used. The alkyl aromatic sulfonic acid referred to here includes a sulfonated alkyl aromatic compound of a lubricating oil fraction of mineral oil, petroleum sulfonic acid such as mahogany acid by-produced during white oil production, linear or branched Synthesis of sulfonated alkylbenzene having alkyl group (by-product from alkylbenzene production plant as raw material of detergent or alkylated product of benzene by polyolefin) or sulfonated alkylnaphthalene such as dinonylnaphthalene Sulfonic acid and the like are included.

  Further, as the phenate used in the present invention, specifically, an alkali metal salt or alkaline earth of alkylphenol having 1 to 2 alkyl groups having 4 to 20 carbon atoms in the presence or absence of elemental sulfur. Examples thereof include metal salts and mixtures thereof.

  The salicylate used in the present invention is specifically an alkali metal salt or alkaline earth of alkyl salicylic acid having 1 to 2 alkyl groups having 4 to 20 carbon atoms in the presence or absence of elemental sulfur. Metal salts and mixtures thereof.

  Among the above organic acid metal salts, magnesium sulfonate is particularly preferable because it can further improve the friction characteristics.

  (H) The base number of the organic acid metal salt is preferably 2 mgKOH / g or more, more preferably 5 mgKOH / g or more, and even more preferably 10 mgKOH / g or more, from the viewpoint of friction characteristics. It is more preferably 50 mgKOH / g or more, particularly preferably 100 mgKOH / g or more, and most preferably 150 mgKOH / g or more. The base number referred to here is 6. JIS K 2501 “Petroleum products and lubricants—neutralization number test method”. The base number [mgKOH / g] measured by the hydrochloric acid method according to the above.

  The organic acid metal salt whose base number satisfies the above conditions includes the above aromatic sulfonic acid, alkylphenol or alkylsalicylic acid, and a base containing an alkali metal (such as an alkali metal oxide or hydroxide) or an alkaline earth metal. It can be obtained by reacting with a base (such as an oxide or hydroxide of an alkaline earth metal) to synthesize a so-called neutral salt (normal salt) and then further basifying it. Such a basified salt includes a basic salt obtained by heating the neutral salt and an excess of an alkali metal base or an alkaline earth metal base in the presence of water; in the presence of carbon dioxide. Carbonate overbased salt (superbasic salt) obtained by reacting the neutral salt with an alkali metal base or alkaline earth metal base; and the neutral salt is an alkali metal base or alkaline earth By reacting with a metal base and a boric acid compound such as boric acid or anhydrous boric acid, or reacting a borate compound such as boric acid or boric anhydride with a carbonate overbased salt (super basic salt) Examples of so-called borate overbased salts (superbasic salts) to be produced; and mixtures thereof.

  The content of the (H) organic acid metal salt is required to be 0.01% by mass, preferably 0.1% by mass or more, based on the total amount of the composition from the viewpoint of friction characteristics, and is preferably 0% or more. More preferably, it is 15% by mass or more. Further, from the viewpoint of thermal stability and antioxidant life, it is necessary that it is 2% by mass or less, preferably 1.5% by mass or less, and 1% by mass or less, based on the total amount of the composition. Is more preferable, and it is still more preferable that it is 0.8 mass% or less.

  In addition, when (H) organic acid metal salt is mix | blended with base oil, you may mix | blend (H) organic acid metal salt as it is, and (H) 20-60 mass% of organic acid metal salt in carrier oil. You may mix | blend the solution melt | dissolved to the extent. However, when a solution containing (H) an organic acid metal salt is used, it is preferable that the base number of the (H) organic acid metal salt not containing carrier oil satisfies the above conditions. For example, when a 50 mass% solution of (H) organic acid metal salt is used, a value obtained by doubling the base number in the solution state preferably satisfies the above conditions.

  Moreover, when using the solution containing (H) organic acid metal salt, content of (H) organic acid metal salt in a lubricating oil composition means the net content of (H) organic acid metal salt. For example, when a 50% by mass solution of (H) organic acid metal salt is used, the solution can be adjusted to a desired amount by weighing and mixing the solution having twice the mass of the desired amount. it can.

  Furthermore, the base number of the solution containing (H) the organic acid metal salt is not particularly limited, but is preferably 2 mgKOH / g or more, more preferably 5 mgKOH / g or more, from the viewpoint of friction characteristics, and 10 mgKOH / g. g is more preferably 50 mgKOH / g or more, particularly preferably 100 mgKOH / g or more, and most preferably 150 mgKOH / g or more.

  In addition, in the lubricating oil composition of the present invention, for the purpose of further improving its performance, (C) a viscosity index improver other than a dispersion-type viscosity index improver, a detergent dispersant, a rust inhibitor, Various additives represented by metal deactivators, pour point depressants, antifoaming agents and the like may be further contained alone or in combination of several kinds.

  (C) Specific examples of the viscosity index improver other than the dispersion type viscosity index improver include a copolymer of one or more monomers selected from various methacrylic esters or a hydrogenated product thereof, ethylene- α-Olefin copolymer (Examples of α-olefin include propylene, 1-butene, 1-pentene, etc.) or a hydride thereof, polyisobutylene or a hydrogenated product thereof, styrene-diene hydrogenated copolymer, and polyalkyl Examples include so-called non-dispersed viscosity index improvers such as styrene. Examples of the detergent dispersant other than (C) the dispersion type viscosity index improver include alkenyl succinimide, sulfonate, salicylate, phenate and the like. In the present invention, one or two or more compounds arbitrarily selected from these viscosity index improvers can be contained in any amount, but the content is usually the total amount of the composition. It is desirable that the content is 0.01 to 10% by mass.

  Specific examples of rust inhibitors include metal soaps such as fatty acid metal salts, lanolin fatty acid metal salts, and oxidized wax metal salts; partial alcohol esters such as sorbitan fatty acid esters; esters such as lanolin fatty acid esters; Examples thereof include sulfonates such as calcium sulfonate and barium sulfonate; oxidized wax; amines; phosphoric acid; In the present invention, one or two or more compounds arbitrarily selected from these rust inhibitors can be contained in any amount, but the content is usually based on the total amount of the composition. It is desirable that it is 0.01-1 mass%.

  Specific examples of the metal deactivator include benzotriazole, thiadiazole, and imidazole compounds. In the present invention, one kind or two or more kinds of compounds arbitrarily selected from these metal deactivators can be contained in any amount, but the content thereof is usually the composition. It is desirable that it is 0.001-1 mass% on the basis of the total amount.

  Specific examples of the pour point depressant include copolymers of one or more monomers selected from various acrylic esters and methacrylic esters or hydrogenated products thereof. In the present invention, one or two or more compounds arbitrarily selected from these pour point depressants can be contained in any amount, but usually the content is the total amount of the composition. It is desirable that the content is 0.01 to 5% by mass.

  Specific examples of the antifoaming agent include silicones such as dimethyl silicone and fluorosilicone. In the present invention, one or two or more compounds arbitrarily selected from these antifoaming agents can be contained in any amount, and the content is usually based on the total amount of the composition. It is desirable that it is 0.001-0.05 mass%.

The kinematic viscosity of the lubricating oil composition of the present invention is not particularly limited, but the kinematic viscosity at 40 ° C. is preferable from the viewpoints of excellent friction characteristics, cooling properties (heat removal properties), and low friction loss due to stirring resistance. Is from 5 to 1,000 mm ² / s, more preferably from 7 to 500 mm ² / s, still more preferably from 10 to ²⁰⁰ mm ² / s. In addition, the viscosity index of the lubricating oil composition of the present invention is not particularly limited, but is preferably 80 to 500, more preferably 100 to 300, from the viewpoint of suppressing oil film decrease at high temperature. Furthermore, although the pour point is also arbitrary, from the viewpoint of pump startability in winter, the pour point is usually preferably −5 ° C. or lower, more preferably −15 ° C. or lower.

  The lubricating oil composition of the present invention can be used as, for example, hydraulic fluid, turbine oil, compressor oil, gear oil, slip guide surface oil, bearing oil, and the like. Among these applications, when used as a hydraulic fluid for hydraulic equipment such as injection molding machines, machine tools, construction machines, steel making equipment, industrial robots, hydraulic elevators, etc., it is possible to exert more excellent effects. . Among them, particularly excellent effects can be exhibited when used as a hydraulic fluid for construction machinery.

EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example , a reference example, and a comparative example, this invention is not limited to a following example at all.

[ Reference Examples 1 to 7 and 9, Example 8 and Comparative Examples 1 to 8]

In Reference Examples 1 to 7 and 9, Example 8 and Comparative Examples 1 to 8, lubricating oil compositions having the compositions shown in Tables 1 to 3 were prepared using the base oils and additives shown below, respectively.
Base oil:
Base oil 1: Paraffin-based highly solvent refined base oil (kinematic viscosity at 40 ° C .: 46.1 mm ² / s, viscosity index 100)
Base oil 2: Paraffinic hydrocracked base oil (kinematic viscosity at 40 ° C .: 46.1 mm ² / s, viscosity index 125)
(A) Phosphorus-containing carboxylic acid compound:
A1: β-dithiophosphorylated propionic acid (B) phosphorus-based antiwear agent:
B1: tricresyl phosphate B2: dioctyl phosphate (C) dispersion type viscosity index improver:
C1: Copolymer of C1-C18 alkyl methacrylate (90 mol%) and morpholinoethyl methacrylate (10 mol%) (number average molecular weight: 80,000)
C2: Copolymer of C1-C18 alkyl methacrylate (90 mol%) and benzoylamino methacrylate (10 mol%) (number average molecular weight: 70,000)
(D) Oiliness agent:
D1: sorbitan monooleate D2: ester of sorbitan and oleic acid (sorbitan monooleate 25 mol%, sorbitan dioleate 40 mol%, sorbitan trioleate 30 mol%, sorbitan tetraoleate 5 mol%)
D3: Triester of glycerin and a mixed fatty acid of acetic acid and a fatty acid having 16 to 20 carbon atoms (fatty acid composition: 66 mol% acetic acid, 30 mol% linear saturated fatty acid having 16 to 20 carbon atoms, straight chain having 18 carbon atoms Unsaturated fatty acid 4 mol%)
D4: ester of glycerin and a branched saturated fatty acid having 16 to 20 carbon atoms (glycerin monoester 25 mol%, glycerin diester 75 mol%, glycerin triester 0 mol%)
(F) Phenolic antioxidants:
F1: 2,6-di-tert-butyl-p-cresol (G) amine-based antioxidant:
G1: Dioctylphenylamine (H) organic acid metal salt:
H1: Magnesium sulfonate (base number: 400 mgKOH / g)
Other additives:
X1: A homopolymer of alkyl methacrylate having 1 to 18 carbon atoms (number average molecular weight: 150,000)
X2: Monotype polybutenyl succinimide obtained by reaction of polybutenyl succinic anhydride and tetraethylenepentamine X3: Calcium dinonylnaphthalene sulfonate (50% by mass solution, carrier oil: paraffinic solvent refined mineral oil, Base number of the solution: 170 mg KOH / g).

  [Thermal stability test]

For each of the lubricating oil compositions of Reference Examples 1 to 7 and 9, Example 8 and Comparative Examples 1 to 8, according to “Lubricant Thermal Stability Method” defined in JIS K 2540, a sample oil of 50 ml was placed in a beaker having a capacity of 50 ml. Was collected, and a coiled catalyst of iron and copper was added, and a thermal stability test was performed in a constant temperature air bath at 140 ° C. (10 days, 20 days). The sample oil after the test was filtered with a filter, and the amount of sludge in the sample oil was measured. The obtained results are shown in Tables 1 to 4.

  "Abrasion resistance test"

For each of the lubricating oil compositions of Reference Examples 1 to 7 and 9, Example 8 and Comparative Examples 1 to 8, the vane pump test defined in ASTM D 2882 was performed, and the weights of the vanes and rings before and after the test were measured. The amount of wear was measured. The test time was 100 hours. The obtained results are shown in Tables 1 to 4.

  [Cylinder squeal prevention test (1)]

For each of the lubricating oil compositions of Reference Examples 1 to 7 and 9 and Example 8 , a cylinder squealing prevention test was performed as follows.

  FIG. 1 is a schematic configuration diagram showing a hydraulic cylinder testing machine used for the test. The test machine shown in FIG. 1 includes a test cylinder main body 1 having one end opened, a piston rod 2 inserted into the test cylinder main body 1 through the opening and arranged so that the axial direction is horizontal, and a piston The drive part 3 provided in the other end side of the rod 2 and the radial load part 4 arrange | positioned at the opening side upper part of the cylinder body 1 for a test are provided. Although not shown in detail, the drive unit 3 has a hydraulic cylinder that reciprocates the piston rod 2 in its axial direction and a load cell that detects vibration of the piston rod at that time. Further, the radial load portion 4 can apply a load vertically downward from the outer peripheral side of the test cylinder body 1.

  FIG. 2 is a cross-sectional view schematically showing the inside of the test cylinder body 1. As shown in the figure, the outer diameter of the piston rod 2 is smaller than the inner diameter of the cylinder body 1, and the piston rod 2 is held horizontally inside the test cylinder body 1 by a guide seal 5 provided at a predetermined position thereof. A space formed by the inner peripheral surface of the cylinder body 1, the piston rod 2, and the guide seal 5 is filled with a lubricating oil composition as a hydraulic fluid. When the piston rod 2 is reciprocated in the axial direction by the drive unit 3, the piston rod 5 is also reciprocated together with the guide seal 5, and the inner peripheral surface of the cylinder body 1 and the guide seal 5 are in a lubricating oil composition. Rub through the object. In this test, the cylinder body 1 for testing, the piston rod 2 and the guide seal 5 were each used for a hydraulic excavator.

  In the testing machine having the above configuration, the temperature of the lubricating oil composition was 90 ° C., the pressure was 24.8 MPa, the radial load was 3.43 kN, and the piston rod 2 was reciprocated in the axial direction at a predetermined speed. The vibration at that time was measured with a load cell, and the prevention of cylinder squealing was evaluated based on the presence or absence of stick-slip. The obtained result is shown to Tables 1-2. In the table, A indicates that stick-slip did not occur in the entire speed range of 0.1 to 4.8 m / min, and B indicates that stick-slip occurred in part of the speed range of 0.1 to 4.8 m / min. In other words, C means that stick slip occurred in the entire speed range of 0.1 to 4.8 m / min.

  [Cylinder squealing prevention test (2)]

For each of the lubricating oil compositions of Reference Examples 4 to 7 and 9 and Example 8 , the cylinder squealing prevention property was evaluated in the same manner as described above except that the pressure was 30.0 MPa. The obtained result is shown to Tables 1-2. In the table, A indicates that stick-slip did not occur in the entire speed range of 0.1 to 4.8 m / min, and B indicates that stick-slip occurred in part of the speed range of 0.1 to 4.8 m / min. In other words, C means that stick slip occurred in the entire speed range of 0.1 to 4.8 m / min.

It is a schematic block diagram which shows the hydraulic cylinder testing machine used in the Example. It is a schematic cross section which shows the inside of the cylinder body for a test of the testing machine shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Test cylinder body, 2 ... Piston rod, 3 ... Drive part, 4 ... Radial load part, 5 ... Guide seal.

Claims (3)

At least one base oil selected from mineral oil, fats and oils, a phosphorus-containing carboxylic acid compound represented by the following general formula (1) , and a phosphorus-containing compound other than the phosphorus-containing carboxylic acid compound, A phosphorus-based antiwear agent not contained, one or more monomers selected from the compounds represented by the following general formula (8), (9) or (10), and the following general formula (11) or (12 And a dispersible viscosity index improver having a number average molecular weight of 10,000 to 200,000, and an ester oily agent. And a lubricating oil composition comprising magnesium sulfonate.

[In Formula (1), R ¹ and R ² may be the same or different, and each represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, and R ³ represents an alkylene group having 1 to 20 carbon atoms. , R ⁴ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, and the carbon numbers X ¹ , X ² , X ³ and X ⁴ may be the same or different and each represents an oxygen atom or a sulfur atom. ]

[Wherein, R ¹⁵ represents a hydrogen atom or a methyl group, and R ¹⁶ represents an alkyl group having 1 to 18 carbon atoms. ]

[Wherein, R ¹⁷ represents a hydrogen atom or a methyl group, and R ¹⁸ represents a hydrocarbon group having 1 to 12 carbon atoms. ]

[Wherein Y ¹ and Y ² may be the same or different and each represents a hydrogen atom, an alkoxy group having 1 to 18 carbon atoms, or a monoalkylamino group having 1 to 18 carbon atoms. ]

[Wherein, R ¹⁹ represents a hydrogen atom or a methyl group, R ²⁰ represents an alkylene group having 2 to 18 carbon atoms, a represents 0 or 1, and Y ³ represents 1 to 30 carbon atoms containing a nitrogen atom. An organic group of ]

[Wherein, R ²¹ represents a hydrogen atom or a methyl group, and Y ⁴ represents a C 1-30 organic group containing a nitrogen atom. ]   The lubricating oil composition according to claim 1, wherein the phosphorus-containing carboxylic acid compound is a phosphorylated carboxylic acid.   The lubricating oil composition according to claim 1 or 2, wherein the phosphorus-based wear inhibitor that is a phosphorus-containing compound other than the phosphorus-containing carboxylic acid compound and does not contain sulfur is a phosphate ester.

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