JP3401380B2 - Lubricating oil composition - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a lubricating oil composition, and more particularly to a lubricating oil composition having excellent oxidative stability.

[0002]

2. Description of the Related Art Conventionally, as antioxidants for lubricating oil,
2,6-di-tert-butyl-p-cresol (DB
PC) is known to have excellent performance and is frequently used in lubricating oils, especially turbine oils. However, since this 2,6-di-tert-butyl-p-cresol has a relatively low molecular weight as an antioxidant, when it is used for a long time under high temperature conditions such as turbine oil, it scatters due to heat. There is a problem that the content concentration is reduced by evaporation and the antioxidant property is not sustained. Further, JP-A-60-156644 describes that a sterically hindered hydroxyphenylcarboxylic acid ester is useful as a stabilizer for synthetic organic polymers, animal and vegetable oils, hydrocarbons, lubricating oils, etc. In the examples, (3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid ester is disclosed. However, this (3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid ester is 2,6-di-
Compared with tert-butyl-p-cresol, scattering
Although it was excellent in the evaporation prevention property, it was inferior in the antioxidant property and was insufficient in performance as a substitute for 2,6-di-tert-butyl-p-cresol. The present inventors have conducted research to develop an antioxidant for a lubricating oil having equivalent or higher performance as an alternative to 2,6-di-tert-butyl-p-cresol, and as a result, hydrogenation When highly refined base oil such as cracked oil or certain synthetic oil contains a specific amount of 3-methyl-5-tert-butyl-4-hydroxyphenyl-substituted fatty acid ester, very excellent oxidation is achieved. It was found that a lubricating oil composition having preventive properties can be obtained, and a patent application was previously filed (Japanese Patent Application No. 6-
330305).

[0003]

However, in recent years, with the increase in output, downsizing and longer life of equipment, gas turbine oil,
In lubricating oils such as compressor oils and hydraulic oils, where oxidation stability is particularly important at high temperatures, there is a marked tendency to require higher oxidation stability. By the way, the above 3
Even when a lubricating oil containing a methyl-5-tert-butyl-4-hydroxyphenyl group-substituted fatty acid ester is used, an oil with a low degree of refinement is used as the base oil, or a highly refined oil is used as the base oil. However, when the lubricating oil is used for a long time under relatively mild oxidizing conditions such as low temperature and low oxygen pressure, the existing 2,6-di-tert-butyl-p
It has been found that the 3-methyl-5-tert-butyl-4-hydroxyphenyl group-substituted fatty acid ester does not always show markedly superior performance as compared with phenolic antioxidants such as -cresol. Therefore,
As a result of further research by the present inventors, 3-methyl-5
-Tert-butyl-4-hydroxyphenyl group-substituted fatty acid ester is used in combination with a specific sulfur- and / or phosphorus-containing compound to provide a lubricant having a higher degree of antioxidation property as compared with the case where each is used alone. The inventors have found that an oil composition can be obtained, and completed the present invention. And also, when the present inventors have used a specific base oil as the base oil of the lubricating oil composition, it has excellent antioxidant properties even at high temperatures, and it can be used for a long time under high temperature conditions. It has also been found that a lubricating oil composition can be obtained in which the antioxidant property does not decrease.

[0004]

A lubricating oil composition according to the present invention comprises: [I] a lubricating base oil, based on the total amount of the composition,
[II] 3-methyl-5- represented by the following general formula (1)
0.1 to 5.0% by mass of tert-butyl-4-hydroxyphenyl group-substituted fatty acid ester, and

[Chemical 2] [In the formula (1), R ¹ represents an alkylene group having 1 to 6 carbon atoms, and R ² represents an alkyl group having 4 to 18 carbon atoms. [III] 0.1 to 5% by mass of one or more compounds selected from the following (III-1) to (III-4) : (III-1) The following general formula (2) Sulfai represented by
A sulfide represented by the following general formula (3), and
Selected from the group consisting of sulfides represented by general formula (4)
At least one sulfide, R ¹² —S _g —R ¹³ (2) [wherein R ¹² and R ¹³ are the same or different;
Well, alkyl group having 1 to 22 carbon atoms and carbon number 6 respectively
~ 20 aryl group, C7-20 alkylaryl
Group or an arylalkyl group having 7 to 20 carbon atoms
And g represents an integer of 1 to 5. ] In _{^{R 14 OCO (CH 2) h}} S j (CH 2) k COOR 15 (3) [(3) equation, even if R ¹⁴ and R ¹⁵ are identical or different
Well, each represents an alkyl group having 2 to 20 carbon atoms, h
And k may be the same or different and each is 2 to 5
Is an integer, and j is 1 or 2. ] In _{^{(R 16 SCH 2 CH 2 COOCH}} 2) 4 C (4) [(4) formula, R ¹⁶ is shows an alkyl group having 8 to 20 carbon atoms
You ] (III-2) phosphites, (III-3) dithiophosphate compound, characterized by being blended (III-4) dithiocarbamates.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The contents of the present invention will be described in more detail below. The lubricating base oil that is the component [I] of the present invention is not particularly limited, and any mineral oil or synthetic oil can be used as long as it is usually used as a lubricating base oil. As the mineral oil-based lubricating base oil, for example, a lubricating oil fraction obtained by distilling crude oil under atmospheric pressure and vacuum distillation, solvent degassing, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrogen Oils such as paraffin-based and naphthene-based oils obtained by appropriately combining chemical purification, purification with sulfuric acid, purification treatment such as clay treatment, and the like can be used. Examples of synthetic lubricating base oils include poly α-olefins (polybutene, 1-octene oligomer, 1-decene oligomer, etc.), alkylbenzene, alkylnaphthalene, diesters (ditridecyl glutarate, di-2-ethylhexyl adipate,
Diisodecyl adipate, ditridecyl adipate, di-2-ethylhexyl sebacate, etc.), polyester (trimellitic acid ester, etc.), polyol ester (trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2)
-Ethyl hexanoate, pentaerythritol pelargonate, etc.), polyoxyalkylene glycol, dialkyldiphenyl ether, polyphenyl ether, etc. can be used. In addition, these base oils may be used alone or in combination of two or more kinds at an arbitrary ratio. The lubricating base oil used in the present invention has no particular condition for its viscosity, but generally has a viscosity of 1 to 100 at 40 ° C.
Those are preferably used for 0 mm ² / s, that of 5~800mm ² / s are more preferably used.

However, the component [II] 3-methyl-5
The synergistic effect with the -tert-butyl-4-hydroxyphenyl group-substituted fatty acid ester is particularly excellent in antioxidant properties and sludge formation-preventing properties. It is preferable to use one or more base oils selected from the components (1) to (I-3). (I-1) Mineral oil having a kinematic viscosity at 40 ° C. of 5 to 200 mm ² / s and a total aromatic content of 15% by mass or less (I-2) a polymer of olefin having 2 to 16 carbon atoms or The hydride having a number average molecular weight of 250 to 4000 (I-3) having 1 to 4 alkyl groups having 1 to 40 carbon atoms, and the total number of carbon atoms of the alkyl groups is 6 to 40 Some alkylbenzene

The component (I-1) has a kinematic viscosity of 5 at 40 ° C.
~200mm a ² / s, and total aromatic content of 15 mass% of mineral oil. The lower limit of kinematic viscosity of component (I-1) at 40 ° C. is 5 mm ² / s, preferably 10 mm ² / s, while the upper limit of kinematic viscosity at 40 ° C. is 200 mm ² / s, It is preferably 100 mm ² / s. If the kinematic viscosity of the component (I-1) at 40 ° C is less than 5 mm ² / s, the oil film may not be formed sufficiently, resulting in poor lubricity. Also, the evaporation loss of the base oil under high temperature conditions is large. Could be. On the other hand, when the kinematic viscosity of the component (I-1) at 40 ° C. exceeds 200 mm ² / s, the fluid resistance increases, and the frictional resistance at the lubricated portion may increase. The upper limit of the total aromatic content of the component (I-1) is 15% by mass, preferably 10% by mass,
It is important that it is more preferably 7% by mass. When the total aromatic content exceeds 15% by mass, the synergistic effect between the component (I-1) and the component [II] may not be obtained so much that the excellent antioxidant property and sludge generation preventive property may not be exhibited. There is. The lower limit of the total aromatic content of the component (I-1) is not particularly limited, but when the total aromatic content is 0% by mass or more and less than 2% by mass, the lubricating oil composition is in use. Since the sludge generated in 1) tends to be poor in solubility, the total aromatic content of the component (I-1) is preferably 2% by mass or more. The total aromatic content in the present invention means ASTM
“Standard Test Method f stipulated in D 2549
or Separation of Representative Aromatics and Nonar
omatics Fractions of High-Boiling Oils by Elution
Chromatography ”based aromatic fraction (arom
atics fraction) content, usually, in this aromatic fraction, alkylbenzene, alkylnaphthalene, anthracene, phenanthrene, and their alkylated compounds, compounds in which four or more benzene rings are condensed,
Alternatively, compounds having a heteroaromatic such as pyridines, quinolines, phenols, and naphthols are included. The method for producing the component (I-1) having the above properties is arbitrary and can be produced by a known method. For example, a distillate of paraffin-based crude oil and / or a mixed-base crude oil by atmospheric distillation; a vacuum distillation distillate (WVGO) of a paraffin-based crude oil and / or a mixed-base crude oil atmospheric distillation residue oil; and / Or mild hydrocracking (MHC) treated oil (HIX); ~
A mixed oil of two or more oils selected from
Or a deasphalted oil (DAO); a mild hydrocracking (MHC) treated oil; a mixed oil of two or more kinds of oils selected from among, etc. as a raw material oil, and this raw material oil as it is or from this raw material oil The recovered lubricating oil fraction is obtained by refining the lubricating oil fraction by a conventional refining method. The refining method here is not particularly limited, and any refining method used in the production of the lubricating base oil can be adopted. Usual purification methods include, for example, (1) hydrocracking, hydrofinishing such as hydrofinishing, (2) solvent purification such as furfural solvent extraction, and (3) dewaxing such as solvent dewaxing or catalytic dewaxing. , (4) White clay refining with acid clay or activated clay, (5)
Chemicals (acid / alkali) such as sulfuric acid cleaning, caustic soda cleaning
Examples include purification. In the present invention, one or more of these may be employed in any combination and in any order. As a reminder, not only the mineral oil obtained by the above-exemplified method but also the mineral oil obtained by other methods can be used alone or in any mixture thereof.
Any of them can be used as the component (I-1) of the present invention as long as the kinematic viscosity at 5 ° C is 5 to 200 mm ² / s and the total aromatic content is 15% by mass or less. When using mineral oil alone as the base oil in the lubricating oil composition of the present invention,
In particular, in terms of excellent synergistic effect with the fatty acid ester which is the component [II], the raw material oil selected from the above is used as it is, or the lubricating oil fraction recovered from this raw material oil is hydrocracked, The product as it is, or the lubricating oil fraction is collected, and then subjected to dewaxing treatment such as solvent dewaxing or contact dewaxing, and then solvent refining treatment or solvent refining treatment followed by solvent dewaxing. (I-1) component produced by performing dewaxing treatment such as contact dewaxing or contacting is preferably 50 mass% or more, more preferably 70 mass% or more, particularly preferably 80 mass% based on the total amount of base oil. It is desirable to include the above. The conditions for hydrocracking referred to here are arbitrary, but usually, in the presence of a hydrocracking catalyst, the total pressure is 6 to 25 MPa, the temperature is 350 to 500 ° C, and the LH is LH.
Decomposition rate of 40 under reaction conditions such as SV0.1-2.0 hr ^-1
Hydrocracking conditions are used so that the content is at least mass%.
Any hydrocracking catalyst can be used, but usually, for example, molybdenum, chromium, tungsten, vanadium, platinum, nickel, copper, iron, cobalt, oxides and / or sulfides thereof, or a mixture thereof, etc. Is used. These catalysts may be used as they are,
It may also be used in the form of being supported on a carrier such as silica-alumina, activated alumina, or zeolite.

The component (I-2) of the present invention is a polymer and / or copolymer of an olefin having 2 to 16 carbon atoms, or a hydride thereof, and has a number average molecular weight of 250 to 4000. is there. The olefin referred to here is an olefin having 2 to 16 carbon atoms, preferably 2 to 12 carbon atoms, and is a so-called α-olefin having a double bond at the terminal, or a so-called internal olefin having the double bond inside. May be Further, it may be a linear olefin or a branched olefin. Specific examples of such an olefin include ethylene, propylene, 1-butene, 2-butene, isobutene, linear or branched pentene (including α-olefin and internal olefin), and linear olefin. Or branched hexene (α-
Olefin, including internal olefin), linear or branched heptene (including α-olefin and internal olefin), linear or branched octene (including α-olefin and internal olefin), linear Linear or branched nonene (including α-olefins and internal olefins), linear or branched decene (including α-olefins and internal olefins), linear or branched undecene (α-
Olefin, including internal olefin), linear or branched dodecene (including α-olefin and internal olefin), linear or branched tridecene (including α-olefin and internal olefin), linear Linear or branched tetradecene (including α-olefins and internal olefins), linear or branched pentadecene (including α-olefins and internal olefins), linear or branched hexadecene (α- Olefins, including internal olefins), and mixtures thereof, among others, especially ethylene, propylene, 1-butene, 2-butene, isobutene, 1-octene, 1-decene, 1-dodecene and mixtures thereof. It is preferably used. Of the present invention
The component (I-2) is a polymer of these olefins or a hydride thereof, and the polymer here means not only a homopolymer of one olefin but also a random copolymer of two or more olefins. It also means a copolymer such as a coalesce, an alternating copolymer and a block copolymer. The olefin homopolymer or copolymer usually contains a double bond, but the component (I-2) of the present invention has a double bond from the viewpoint of excellent heat / oxidation stability. It is preferable to use a homopolymer or copolymer obtained by hydrogenating. The method for producing the olefin polymer or the hydride thereof as the component (I-2) is arbitrary and is not limited at all, but generally,
Organic thermal catalysts such as benzoyl peroxide by non-catalytic thermal reaction; aluminum chloride, aluminum chloride-polyhydric alcohol system, aluminum chloride-titanium tetrachloride system, aluminum chloride-alkyltin halide system, boron fluoride, etc. Friedel-Crafts type catalyst; Ziegler type catalyst such as organic aluminum chloride-titanium tetrachloride, organic aluminum-titanium tetrachloride type; metallocene type catalyst such as aluminoxane-zirconocene type or ionic compound-zirconocene type; aluminum chloride-base It can be obtained by homopolymerization or copolymerization of the above-mentioned olefins using a known catalyst system such as a Lewis acid complex type catalyst such as a system or a boron fluoride-base system. The method for obtaining the hydrogenated product of the olefin polymer is also arbitrary, and for example, it is obtained by hydrogenating the olefin polymer with hydrogen in the presence of a known hydrogenation catalyst to saturate the double bond existing in the olefin polymer. To be Also, some catalysts can carry out the olefin polymerization and the hydrogenation of the double bond existing in the polymer in one step without going through the two-step process of olefin polymerization and hydrogenation of the obtained polymer. is there. Examples of the component (I-2) of the present invention include heat / oxidation stability,
From the viewpoint of excellent viscosity-temperature characteristics and low-temperature fluidity, ethylene-propylene copolymer, polybutene (butane-butene (mixture of 1-butene, 2-butene and isobutene) fraction produced as a by-product during naphtha thermal decomposition) fraction Copolymer obtained by polymerization), 1-octene oligomer, 1-decene oligomer, 1-dodecene oligomer and hydrides thereof,
And more preferably a mixture of these,
Ethylene-propylene copolymer hydride, polybutene hydride, 1-octene oligomer hydride, 1-decene oligomer hydride, 1-dodecene oligomer hydride, and mixtures thereof are particularly preferably used.
Incidentally, ethylene-propylene copolymer, polybutene and poly-α-which are currently commercially available for lubricating base oils.
Synthetic oils such as olefins are usually those in which the double bond has already been hydrogenated, and commercially available products thereof can also be preferably used in the present invention. The lower limit of the number average molecular weight of the component (I-2) is 250, preferably 350, and the upper limit thereof is 4000, preferably 1500. When the number average molecular weight is less than 250, the oil film may not be sufficiently formed, resulting in poor lubricity, and the evaporation loss of the base oil under high temperature conditions may increase. On the other hand, when the number average molecular weight is more than 4000, the fluid resistance increases, which may increase the frictional resistance at the lubrication point. (I-2) is an olefin polymer or the viscosity of the hydride is a component is not particularly limited, preferred kinematic viscosity 5 to 200 mm ² / s at 40 ° C., more preferably from 10 to 100 mm ² / s.

The component (I-3) of the present invention is an alkylbenzene having 1 to 4 alkyl groups having 1 to 40 carbon atoms, and the total number of carbon atoms of the alkyl groups is 6 to 40.
It has 1 carbon atom because of its excellent oxidative stability and availability.
Alkylbenzene having 1 to 4 alkyl groups of -40 to 40 and the total number of carbon atoms of the alkyl groups is 12 to 40 is preferable, and the alkyl group having 1 to 30 carbon atoms is 1
To 4 and the total number of carbon atoms of the alkyl group is 15 to 30
Is more preferably alkylbenzene. An alkylbenzene in which the total number of carbon atoms in the alkyl group is less than 6 may be inferior in lubricity due to insufficient oil film formation, and may cause a large evaporation loss of the base oil under high temperature conditions. On the other hand, since alkylbenzene in which the total number of carbon atoms of the alkyl group exceeds 40 has a large fluid resistance,
Frictional resistance at lubricated points may increase. The alkyl group having 1 to 40 carbon atoms may be linear or branched. Specifically, for example, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, linear or branched butyl group, linear or branched group. A pentyl group, a straight-chain or branched hexyl group, a straight-chain or branched heptyl group, a straight-chain or branched octyl group, a straight-chain or branched nonyl group, a straight-chain or branched decyl group, a straight chain A chain or branched undecyl group, a straight chain or branched dodecyl group, a straight chain or branched tridecyl group, a straight chain or branched tetradecyl group, a straight chain or branched pentadecyl group,
Straight-chain or branched hexadecyl group, straight-chain or branched heptadecyl group, straight-chain or branched octadecyl group, straight-chain or branched nonadecyl group, straight-chain or branched icosyl group, straight-chain or branched Henicosyl group, straight-chain or branched docosyl group, straight-chain or branched tricosyl group, straight-chain or branched tetracosyl group, straight-chain or branched pentacosyl group, straight-chain or branched hexacosyl group, direct Chain or branched heptacosyl group, straight chain or branched octacosyl group, straight chain or branched nonacosyl group, straight chain or branched triacontyl group, straight chain or branched hentriacontyl group, straight chain or branched chain Branched dotriacontyl group, straight chain or branched tritriacontyl group, straight chain or branched tetracontyl group, straight chain or branched pentacontyl group, straight chain or branched chain Sakonchiru group, straight or branched Heputakonchiru group, a linear or branched Okutakonchiru group,
A straight chain or branched nonacontyl group, a straight chain or branched tetracontyl group, and the like can be mentioned. This alkyl group may be linear or branched, but a branched alkyl group is preferable from the viewpoint of viscosity-temperature characteristics and low temperature fluidity, and in particular from the viewpoint of availability, propylene is preferable. More preferred are branched alkyl groups derived from olefin oligomers such as, butene and isobutylene. The number of alkyl groups held by the alkylbenzene component (I-3) is 1 to 4
However, the alkylbenzenes having one or two alkyl groups, that is, monoalkylbenzenes, dialkylbenzenes, and mixtures thereof, which are excellent in thermal and oxidative stability and are available, are the components (I-3). Most preferably used as Needless to say, (I-
The alkylbenzene as the component 3) may have a single structure alkylbenzene as long as it has 1 to 4 alkyl groups having 1 to 40 carbon atoms and the total number of carbon atoms of the alkyl groups is 6 to 40. It may be a mixture of alkylbenzenes having different structures. Although the viscosity of the alkylbenzene as the component (I-3) is not particularly limited, the preferable kinematic viscosity is 5 to 200 mm ² / s at 40 ° C., more preferably 10 to 1
It is 00 mm ² / s. The method for producing the alkylbenzene used as the component (I-3) is arbitrary and is not particularly limited, but it can be generally produced by the following synthetic method. Specific examples of the aromatic compound as a raw material include benzene, toluene, xylene, ethylbenzene,
Methyl ethylbenzene, diethylbenzene, a mixture thereof, or the like is used. Specific examples of the alkylating agent include lower monoolefins such as ethylene, propylene, butene, and isobutylene, preferably linear or branched olefins having 6 to 40 carbon atoms obtained by polymerization of propylene; waxes, Heavy oil, petroleum fraction, linear or branched olefin having 6 to 40 carbon atoms obtained by thermal decomposition of polyethylene, polypropylene, etc .; n-paraffin is separated from petroleum fraction of kerosene, light oil, etc. A linear olefin having 6 to 40 carbon atoms, which is obtained by olefination of C. with a catalyst; and mixtures thereof can be used. As the alkylation catalyst in the alkylation, known catalysts such as Friedel-Crafts type catalysts such as aluminum chloride and zinc chloride; acidic catalysts such as sulfuric acid, phosphoric acid, silicotungstic acid, hydrofluoric acid and activated clay; Is used.

When the above component (I-2) and / or component (I-3) is used as the component [I] in the lubricating oil composition of the present invention, the location where the lubricating oil composition of the present invention is used For the purpose of improving the swelling property of a member such as a rubber seal material used in, the kinematic viscosity at 40 ° C. is 5 to 2 if necessary.
300 mm ² / s, preferably of 10 to 100 mm ² / s, other mineral base oil, an ester based base oil, ether-based base oil, and mixtures thereof, 40 weight base oil total amount of [I] Component %
Less, preferably less than 30% by weight, more preferably 20
It is possible to contain less than mass%. The above-mentioned mineral oil-based base oil used in combination with the component (I-2) and / or the component (I-3) is not particularly limited in the total aromatic content, and may be a paraffinic base oil or a mixed base crude oil. The lubricating oil fraction obtained by pressure distillation and vacuum distillation is subjected to a single refining process such as hydrorefining, solvent refining, dewaxing, clay refining, chemical (acid / alkali) refining, or the same or similar refining method. A paraffinic system having any total aromatic content, which is purified by combining two or more optional purification methods in any order, including
Mineral oil base oils such as naphthene bases can be used. However, especially when using a mineral base oil, [II]
It is more preferable to also use the component (I-1) of the present invention together, because it is excellent in synergistic effect with the fatty acid ester as a component. Specific examples of the above-mentioned ester base oil used in combination with the component (I-2) and / or the component (I-3) include ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, and ditril. Diester oil represented by decyl adipate, di-3-ethylhexyl sebacate, etc .; trimethylolpropane tricaprylate, trimethylolpropane tripelargonate, pentaerythritol tetra (2-ethylhexanoate), pentaerythritol tetrapelargonate, etc. And a mixture of two or more kinds of ester base oils selected from these. Specific examples of the ether base oil include polyglycol oils represented by polyoxyethylene glycol, polyoxypropylene glycol, polyoxyethyleneoxypropylene glycol, polyoxybutylene glycol, etc .; Examples thereof include alkyl ether compounds and dialkyl ether compounds; diphenyl ether, polyphenylene ether, and a mixture of two or more kinds of ether base oils selected from these.

The component [II] of the present invention is 3-methyl-5-tert-butyl- which is represented by the following general formula (1).
It is a 4-hydroxyphenyl group-substituted fatty acid ester.

[Chemical 3] In the above formula (1), R ¹ is a straight chain or branched alkylene group having 1 to 6 carbon atoms, and R ² is a straight chain having 4 to 18 carbon atoms.
Alternatively, each represents a branched alkyl group. Examples of R ¹ include methylene group, methylmethylene group, ethylene group (dimethylene group), ethylmethylene group, propylene group (methylethylene group), trimethylene group, straight chain or branched butylene group, straight chain or branched chain. And a straight-chain or branched hexylene group. R ¹ is an alkylene group having 1 to 2 carbon atoms, specifically, for example, a methylene group, a methylmethylene group, an ethylene group (a dimethylene group) since it can be produced in a reaction step with a small amount of [II] component.
And the like are more preferable. As R ² , [II]
R ² in the above general formula (1) is an alkyl group having 4 to 18 carbon atoms, specifically, for example, an n-butyl group, an isobutyl group, in view of excellent solubility of the component in a lubricating base oil.
sec-butyl group, tert-butyl group, straight-chain or branched pentyl group, straight-chain or branched hexyl group, straight-chain or branched heptyl group, straight-chain or branched octyl group,
Straight-chain or branched nonyl group, straight-chain or branched decyl group, straight-chain or branched undecyl group, straight-chain or branched dodecyl group, straight-chain or branched tridecyl group, straight-chain or branched An alkyl group such as a tetradecyl group, a linear or branched pentadecyl group, a linear or branched hexadecyl group, a linear or branched heptadecyl group, a linear or branched octadecyl group, and the like. Among them, a linear or branched alkyl group having 6 to 12 carbon atoms is more preferable, and a branched alkyl group having 6 to 12 carbon atoms is particularly preferable. 3-Methyl-5-tert- which is preferable as the component [II]
In the butyl-4-hydroxyphenyl group-substituted fatty acid ester, in the formula (1), R ¹ is an alkylene group having 1 to 2 carbon atoms, and R ² is a linear or branched alkyl group having 6 to 12 carbon atoms. Is a fatty acid ester, R ¹ is an alkylene group having 1 to ² carbon atoms, and R ² is 6 to 1 carbon atoms.
The fatty acid ester which is a branched alkyl group of 2 is [II]
Particularly preferred as a component. As a matter of course, as the component [II] of the present invention, one compound represented by the formula (1) may be used alone, or two or more compounds represented by the formula (1) may be used. You may use the mixture which mixed the compound in arbitrary ratios. Specific examples of preferred compounds as the component [II] of the present invention are described below. (3-Methyl-5-tert-butyl-4-hydroxyphenyl) acetic acid n-hexyl,
(3-Methyl-5-tert-butyl-4-hydroxyphenyl) isohexyl acetate, (3-methyl-5-te
rt-Butyl-4-hydroxyphenyl) acetic acid n-heptyl, (3-methyl-5-tert-butyl-4-hydroxyphenyl) isoheptyl 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)
2-ethylhexyl acetate, (3-methyl-5-tert
-Butyl-4-hydroxyphenyl) acetic acid n-nonyl,
(3-Methyl-5-tert-butyl-4-hydroxyphenyl) isononyl acetate, (3-methyl-5-ter
t-Butyl-4-hydroxyphenyl) acetic acid n-decyl, (3-methyl-5-tert-butyl-4-hydroxyphenyl) acetic acid isodecyl, (3-methyl-5-t
ert-Butyl-4-hydroxyphenyl) acetic acid n-undecyl, (3-methyl-5-tert-butyl-4-)
Hydroxyphenyl) isoundecyl acetate, (3-methyl-5-tert-butyl-4-hydroxyphenyl)
N-dodecyl acetate, (3-methyl-5-tert-butyl-4-hydroxyphenyl) isododecyl acetate, (3
-Methyl-5-tert-butyl-4-hydroxyphenyl) n-hexyl propionate, (3-methyl-5-
tert-Butyl-4-hydroxyphenyl) isohexyl propionate, n-heptyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate, (3-methyl-5-tert-butyl-4-hydroxyphenyl) ) Isoheptyl propionate, (3-methyl-5-tert-butyl-4-hydroxyphenyl)
N-octyl propionate, (3-methyl-5-ter
t-Butyl-4-hydroxyphenyl) isooctyl propionate, (3-methyl-5-tert-butyl-4)
2-ethylhexyl-hydroxyphenyl) propionate, n-nonyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate, (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionic acid Isononyl, (3-methyl-5-tert-
N-decyl butyl-4-hydroxyphenyl) propionate, isodecyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate, (3-methyl-5-tert-butyl-4-hydroxyphenyl)
N-Undecyl propionate, (3-methyl-5-te
rt-Butyl-4-hydroxyphenyl) isoundecyl propionate, n-dodecyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate, (3-methyl-5-tert-butyl-4-hydroxyphenyl) ) Isododecyl propionate, and mixtures thereof. The method for producing the 3-methyl-5-tert-butyl-4-hydroxyphenyl group-substituted fatty acid ester, which is the component [II] of the present invention, is arbitrary and is not particularly limited by the production method. For reference, an example thereof is (3-methyl-5-tert-butyl-4-hydroxyphenyl).
2-Methyl-6 is used to produce a propionic acid ester.
Methyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate can be obtained by reacting -tert-butylphenol and methyl acrylate in the presence of a basic catalyst such as sodium metal. If necessary, this (3-methyl-5-te
By transesterifying methyl rt-butyl-4-hydroxyphenyl) propionate with another aliphatic alcohol having 4 to 18 carbon atoms, (3-methyl-5-
An esterified product of tert-butyl-4-hydroxyphenyl) propionic acid and an aliphatic alcohol having 4 to 18 carbon atoms can be easily obtained. The lower limit of the content of the [II] component in the lubricating oil composition of the present invention is 0.1% by mass, preferably 0.2% by mass, based on the total amount of the lubricating oil composition, while the upper limit thereof is Is 5.0% by mass, preferably 3.0% by mass. The content of the component [II] is 0.1 based on the total amount of the lubricating oil composition.
When it is less than mass%, the effect of improving the oxidation stability exhibited by the component [II] is not sufficient, while when the upper limit exceeds 5.0 mass% based on the total amount of the lubricating oil composition, the content is justified. However, the effect of improving the oxidation stability is not obtained and it is economically disadvantageous, so that it is not preferable.

The component [III] of the present invention comprises the following (III-1)
It is one or more kinds of sulfur and / or phosphorus-containing compounds selected from (III-4). (III-1) sulfides, (III-2) phosphites, (III-3) dithiophosphates, (III-4) dithiocarbamates

The above-mentioned component (III-1) includes, for example, dihydrocarbyl polysulfide represented by the following general formula (2). R ¹² —S _g —R ¹³ (2) In formula (2), R ¹² and R ¹³ may be the same or different, and each is a linear or branched alkyl group having 1 to 22 carbon atoms or carbon. Aryl group having 6 to 20 carbon atoms and 7 to
20 is an alkylaryl group or an arylalkyl group having 7 to 20 carbon atoms, and g is 1 to 5, preferably 1 to
2, more preferably 2. Specific examples of R ¹² and R ¹³ include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-
Butyl group, tert-butyl group, linear or branched pentyl group, linear or branched hexyl group, cyclohexyl group,
Straight-chain or branched heptyl group, straight-chain or branched octyl group (tert-octyl group, etc.), straight-chain or branched nonyl group, straight-chain or branched decyl group, straight-chain or branched undecyl group, straight-chain or Branched dodecyl group (tert-dodecyl group, etc.), straight-chain or branched tridecyl group, straight-chain or branched tetradecyl group, straight-chain or branched pentadecyl group, straight-chain or branched hexadecyl group (2-methylpentadecyl group) , Tert-hexadecyl group, etc.), straight chain or branched heptadecyl group, straight chain or branched octadecyl group, straight chain or branched nonadecyl group, straight chain or branched icosyl group, straight chain or branched henicosyl group, straight chain Or an alkyl group such as a branched docosyl group; an alkenyl group such as a propenyl group or a butenyl group; an aryl group such as a phenyl group or a naphthyl group (including all isomers) Group: tolyl group, ethylphenyl group, propylphenyl group, butylphenyl group, pentylphenyl group, hexylphenyl group, heptylphenyl group, octylphenyl group, nonylphenyl group, decylphenyl group, undecylphenyl group, dodecylphenyl group, Xylyl group, ethylmethylphenyl group, diethylphenyl group, dipropylphenyl group, dibutylphenyl group, methylnaphthyl group, ethylnaphthyl group, propylnaphthyl group, butylnaphthyl group, dimethylnaphthyl group, ethylmethylnaphthyl group, diethylnaphthyl group, An alkylaryl group such as a dipropylnaphthyl group or a dibutylnaphthyl group (the alkyl moiety of these alkylaryl groups may be linear or branched, and the substitution position of the alkyl moiety on the aryl group is arbitrary); and a benzyl group. Enechiru group, an arylalkyl group, such as phenylpropyl group (the alkyl portions of these arylalkyl group may be linear or branched, substituted position of the aryl moiety is optional.) Can be mentioned. Among the specific examples of R ¹² and R ¹³ , an alkyl group having 3 to 18 carbon atoms derived from propylene or isobutene; an aryl group having 6 to 8 carbon atoms; an alkylaryl group having 7 to 8 carbon atoms; Alternatively, an arylalkyl group having 7 to 8 carbon atoms is preferable. Examples of these groups include an isopropyl group, a branched hexyl group derived from a propylene dimer, a branched nonyl group derived from a propylene trimer,
A branched dodecyl group derived from a propylene tetramer, a branched pentadecyl group derived from a propylene pentamer,
Branched octadecyl group derived from propylene hexamer, tert-butyl group, branched octyl group derived from isobutene dimer, branched dodecyl group derived from isobutene trimer, isobutene tetramer An alkyl group such as a branched hexadecyl group derived from the body (these alkyl groups include all branched isomers); a propenyl group,
Alkenyl group such as butenyl group; alkylaryl group such as phenyl group, tolyl group, ethylphenyl group, xylyl group (the alkyl moiety of these alkylaryl groups may be linear or branched, and the substitution position of the alkyl moiety on the aryl group) Is arbitrary.); And an arylalkyl group such as a benzyl group and a phenylethyl group (the substitution position of the phenyl group is arbitrary). Of these, C3 to C1 derived from propylene or isobutene
Particularly preferred are 8 and especially 6 to 15 alkyl groups. Specific examples of the dihydrocarbyl polysulfide represented by the above general formula (2) include dimethyl polysulfide such as dimethyl monosulfide and dimethyl disulfide;
Diethyl polysulfide such as diethyl monosulfide and diethyl disulfide; Di n-propyl polysulfide such as di-n-propyl monosulfide and di-n-propyl disulfide; Diisopropyl polysulfide such as diisopropyl monosulfide and diisopropyl disulfide; Di-n-butyl Di-n-butyl polysulfide such as monosulfide and di-n-butyl disulfide; Diisobutyl polysulfide such as diisobutyl monosulfide and diisobutyl disulfide; Disec-butyl monosulfide and disec
-Disec-butyl polysulfide such as butyl disulfide; ditert-butyl monosulfide, dit
Di-tert-butyl polysulfide such as ert-butyl disulfide; di (linear or branched pentyl) monosulfide, di (linear or branched pentyl) disulfide such as di (linear or branched pentyl) disulfide; di Di (linear or branched hexyl) monosulfide, di (linear or branched hexyl) disulfide, etc. di (linear or branched hexyl) polysulfide; dicyclohexyl monosulfide, dicyclohexyl disulfide, etc .; di (direct) Chain (branched or branched heptyl) monosulfide, di (linear or branched heptyl) disulfide, etc. di (linear or branched heptyl) polysulfide; di te-octyl monosulfide, di tert-octyl disulfide, etc. t- octyl polysulfide;
Di (linear or branched octyl) monosulfide, di (linear or branched octyl) disulfide, etc., di (linear or branched octyl) polysulfide; di (linear or branched nonyl) monosulfide, di ( Di (linear or branched nonyl) polysulfide such as linear or branched nonyl) disulfide; di (linear or branched decyl) monosulfide, di (direct or branched decyl) disulfide, etc. Chain (branched or branched decyl) polysulfide; di (straight or branched undecyl) monosulfide, di (straight or branched undecyl) disulfide, or other di (straight or branched undecyl) polysulfide;
Di tert-dodecyl monosulfide, di tert-
Di-tert-dodecyl polysulfide such as dodecyl disulfide; di (linear or branched dodecyl) monosulfide, di (linear or branched dodecyl) disulfide such as di (linear or branched dodecyl) polysulfide; di (direct) Di (linear or branched tridecyl) polysulfides such as chain or branched tridecyl) monosulfide, di (linear or branched tridecyl) disulfide;
Di (linear or branched tetradecyl) monosulfide,
Di (linear or branched tetradecyl) disulfide or other di (linear or branched tetradecyl) polysulfide;
Di (linear or branched pentadecyl) monosulfide,
Di (linear or branched pentadecyl) disulfide, such as di (linear or branched pentadecyl) disulfide;
Di2-methylpentadecyl monosulfide, di2-methylpentadecyl disulfide, etc .; di2-methylpentadecyl polysulfide; ditert-hexadecyl monosulfide, ditert-hexadecyl disulfide, etc. Di (linear or branched hexadecyl) monosulfide, di (linear or branched hexadecyl) disulfide, etc. di (linear or branched hexadecyl) polysulfide; di (linear or branched heptadecyl) monosulfide, di Di (linear or branched heptadecyl) polysulfide such as (linear or branched heptadecyl) disulfide; di (linear or branched octadecyl) monosulfide, di (linear or branched octadecyl) disulfide such as di (linear or branched octadecyl) disulfide Straight chain or Branch octadecyl) polysulfide; di- (straight or branched nonadecyl) monosulfide, di (straight or branched nonadecyl) disulfide and di the (linear or branched nonadecyl) polysulfide;
Di (linear or branched icosyl) monosulfide, di (linear or branched icosyl) disulfide, etc. di (linear or branched icosyl) polysulfide; di (linear or branched henicosyl) monosulfide, di ( Di (linear or branched henicosyl) polysulfides such as linear or branched henicosyl) disulfide; di (direct or branched docosyl) monosulfide, di (direct or branched docosyl) disulfide, etc. (Chain or branched docosyl) polysulfide; dipropenyl monosulfide such as dipropenyl monosulfide, dipropenyl disulfide; dibutenyl polysulfide such as dibutenyl monosulfide, dibutenyl disulfide; diphenyl such as diphenyl monosulfide, diphenyl disulfide Risarufaido; dinaphthyl sulfide, dinaphthyl polysulfide such as dinaphthyl distearate disulfide; ditolyl mono sulfide, ditolyl such ditolyl distearate disulfide polysulfides;
Diethylphenyl polysulfide such as diethylphenyl monosulfide, diethylphenyldisulfide; Dipropylphenylpolysulfide such as dipropylphenylmonosulfide, dipropylphenyldisulfide; Dibutylphenylpolysulfide such as dibutylphenylmonosulfide, dibutylphenyldisulfide; Dipentylphenyl Monosulfide,
Dipentylphenyl polysulfide such as dipentylphenyl disulfide; Dihexylphenyl monosulfide such as dihexylphenyl monosulfide, dihexylphenyl disulfide; Diheptylphenyl polysulfide such as diheptylphenyl monosulfide, Diheptylphenyl disulfide; Dioctylphenyl monosulfide, dioctylphenyl Dioctylphenyl polysulfide such as disulfide; Dinonylphenyl polysulfide such as dinonylphenyl monosulfide and dinonylphenyl disulfide; Didecylphenyl polysulfide such as didecylphenyl monosulfide and didecylphenyl disulfide;
Diundecylphenyl monosulfide, diundecylphenyl polysulfide such as diundecylphenyl disulfide; didodecylphenyl monosulfide,
Didodecylphenyl polysulfide such as didodecylphenyl disulfide; dixylyl monosulfide,
Dixylylpolysulfides such as dixylyldisulfide; Diethylmethylphenylpolysulfides such as diethylmethylphenylmonosulfide, diethylmethylphenyldisulfide; Di (diethylphenyl) such as di (diethylphenyl) monosulfide, di (diethylphenyl) disulfide Polysulfide; Di (dipropylphenyl) polysulfide such as di (dipropylphenyl) monosulfide, di (dipropylphenyl) disulfide; Di (dibutylphenyl) such as di (dibutylphenyl) monosulfide, di (dibutylphenyl) disulfide ) Polysulfide; dimethylnaphthylpolysulfide such as dimethylnaphthylmonosulfide, dimethylnaphthyldisulfide; diethylnaphthylmonosa Diethylnaphthyl polysulfides such as Fide and diethylnaphthyldisulfide; Dipropylnaphthylpolysulfides such as dipropylnaphthylmonosulfide and dipropylnaphthyldisulfide; Dibutylnaphthylpolysulfides such as dibutylnaphthyldisulfide and dibutylnaphthylpolysulfide; Dibenzylmonosulfide, Examples thereof include dibenzyl polysulfide such as dibenzyl disulfide; diphenethyl polysulfide such as diphenethyl monosulfide and diphenethyl disulfide; diphenylpropyl polysulfide such as diphenylpropyl monosulfide and diphenylpropyl disulfide, and a mixture thereof.

Another compound contained in the sulfides as the component (III-1) is a diester polysulfide represented by the following general formula (3). ^{_{R 14 OCO (CH 2) h}} S j (CH 2) k COOR 15 (3) (3) formula, R ¹⁴ and R ¹⁵ may be the same or different, each 2 to 20 carbon atoms, preferably 4 In the straight-chain or branched alkyl group of -20, h and k may be the same or different, and each is 2-5, preferably 2, and j is 1-2, preferably 2. R ¹⁴ and R
Specific examples of ¹⁵ include ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, linear or branched pentyl group, linear or branched hexyl group. , Straight chain or branched heptyl group, straight chain or branched octyl group, straight chain or branched nonyl group, straight chain or branched decyl group, straight chain or branched undecyl group, straight chain or branched dodecyl group, straight chain Chain or branched tridecyl group, straight chain or branched tetradecyl group, straight chain or branched pentadecyl group, straight chain or branched hexadecyl group, straight chain or branched heptadecyl group, straight chain or branched octadecyl group, straight chain or Mention may be made of branched nonadecyl groups, straight-chain or branched icosyl groups. General formula (3)
Specific examples of the diester polysulfide represented by are C ₄ H ₉ OCO (CH ₂ ) ₂ S (CH ₂ ) ₂ COOC
₄ H ₉ , C ₄ H ₉ OCO (CH ₂ ) ₂ S ₂ (CH ₂ ) ₂ COOC ₄
H ₉ , C ₅ H ₁₁ OCO (CH ₂ ) ₂ S (CH ₂ ) ₂ COOC ₅
H ₁₁ , C ₅ H ₁₁ OCO (CH ₂ ) ₂ S ₂ (CH ₂ ) ₂ COOC
₅ H ₁₁ , C ₆ H ₁₃ OCO (CH ₂ ) ₂ S (CH ₂ ) ₂ COOC
₆ H ₁₃ , C ₆ H ₁₃ OCO (CH ₂ ) ₂ S ₂ (CH ₂ ) ₂ COO
_{C 6 H 13, C 7 H} 15 OCO (CH 2) 2 S (CH 2) 2 COO
_{C 7 H 15, C 7 H} 15 OCO (CH 2) 2 S 2 (CH 2) 2 CO
OC ₇ H ₁₅ , C ₈ H ₁₇ OCO (CH ₂ ) ₂ S (CH ₂ ) ₂ CO
OC ₈ H ₁₇ , C ₈ H ₁₇ OCO (CH ₂ ) ₂ S ₂ (CH ₂ ) ₂ C
OOC ₈ H ₁₇ , C ₉ H ₁₉ OCO (CH ₂ ) ₂ S (CH ₂ ) ₂ C
OOC ₉ H ₁₉ , C ₉ H ₁₉ OCO (CH ₂ ) ₂ S ₂ (CH ₂ ) ₂
COOC ₉ H ₁₉ , C ₁₀ H ₂₁ OCO (CH ₂ ) ₂ S (CH ₂ )
₂ COOC ₁₀ H ₂₁ , C ₁₀ H ₂₁ OCO (CH ₂ ) ₂ S ₂ (CH
₂ ) ₂ COOC ₁₀ H ₂₁ , C ₁₁ H ₂₃ OCO (CH ₂ ) ₂ S (C
H ₂ ) ₂ COOC ₁₁ H ₂₃ , C ₁₁ H ₂₃ OCO (CH ₂ ) ₂ S ₂
(CH ₂ ) ₂ COOC ₁₁ H ₂₃ , C ₁₂ H ₂₅ OCO (CH ₂ ) ₂
S (CH ₂ ) ₂ COOC ₁₂ H ₂₅ , C ₁₂ H ₂₅ OCO (C
H ₂ ) ₂ S ₂ (CH ₂ ) ₂ COOC ₁₂ H ₂₅ , C ₁₃ H ₂₇ OCO
(CH ₂ ) ₂ S (CH ₂ ) ₂ COOC ₁₃ H ₂₇ , C ₁₃ H ₂₇ OC
O (CH ₂ ) ₂ S ₂ (CH ₂ ) ₂ COOC ₁₃ H ₂₇ , C ₁₄ H ₂₉
OCO (CH ₂ ) ₂ S (CH ₂ ) ₂ COOC ₁₄ H ₂₉ , C ₁₄ H
₂₉ OCO (CH ₂ ) ₂ S ₂ (CH ₂ ) ₂ COOC ₁₄ H ₂₉ , C
₁₅ H ₃₁ OCO (CH ₂ ) ₂ S (CH ₂ ) ₂ COOC ₁₅ H ₃₁ ,
C ₁₅ H ₃₁ OCO (CH ₂ ) ₂ S ₂ (CH ₂ ) ₂ COOC ₁₅ H
₃₁ , C ₁₆ H ₃₃ OCO (CH ₂ ) ₂ S (CH ₂ ) ₂ COOC ₁₆
H ₃₃ , C ₁₆ H ₃₃ OCO (CH ₂ ) ₂ S ₂ (CH ₂ ) ₂ COO
C ₁₆ H ₃₃ , C ₁₇ H ₃₅ OCO (CH ₂ ) ₂ S (CH ₂ ) ₂ CO
OC ₁₇ H ₃₅ , C ₁₇ H ₃₅ OCO (CH ₂ ) ₂ S ₂ (CH ₂ ) ₂
COOC ₁₇ H ₃₅ , C ₁₈ H ₃₇ OCO (CH ₂ ) ₂ S (C
H ₂ ) ₂ COOC ₁₈ H ₃₇ , C ₁₈ H ₃₇ OCO (CH ₂ ) ₂ S ₂
(CH ₂ ) ₂ COOC ₁₈ H ₃₇ , C ₁₉ H ₃₉ OCO (CH ₂ ) ₂
S (CH ₂ ) ₂ COOC ₁₉ H ₃₉ , C ₁₉ H ₃₉ OCO (C
H ₂ ) ₂ S ₂ (CH ₂ ) ₂ COOC ₁₉ H ₃₉ , C ₂₀ H ₄₁ OCO
(CH ₂ ) ₂ S (CH ₂ ) ₂ COOC ₂₀ H ₄₁ , C ₂₀ H ₄₁ OC
_{O (CH 2) 2 S 2} (CH 2) 2 COOC 20 H 41 or a mixture thereof.

Still another compound contained in the sulfides as the component (III-1) is a tetraester tetrasulfide represented by the following general formula (4). (R ¹⁶ SCH ₂ CH ₂ COOCH ₂ ) ₄ C (4) In the formula (4), R ¹⁶ has 8 to 20 carbon atoms, preferably 12 to
13 represents a linear or branched alkyl group. Specific examples of R ¹⁶ include straight chain or branched octyl group, straight chain or branched nonyl group, straight chain or branched decyl group, straight chain or branched undecyl group, straight chain or branched dodecyl group, straight chain or Branched tridecyl group, straight chain or branched tetradecyl group,
Straight-chain or branched pentadecyl group, straight-chain or branched hexadecyl group, straight-chain or branched heptadecyl group, straight-chain or branched octadecyl group, straight-chain or branched nonadecyl group, straight-chain or branched icosyl group In particular, a straight chain or branched dodecyl group and a straight chain or branched tridecyl group are preferable. Specific examples of the tetraester tetrasulfide represented by the general formula (4) include (C ₈ H ₁₇ SCH ₂ CH
₂ COOCH ₂ ) ₄ C, (C ₉ H ₁₉ SCH ₂ CH ₂ COOCH
₂ ) ₄ C, (C ₁₀ H ₂₁ SCH ₂ CH ₂ COOCH ₂ ) ₄ C,
(C ₁₁ H ₂₃ SCH ₂ CH ₂ COOCH ₂ ) ₄ C, (C ₁₂ H ₂₅
SCH ₂ CH ₂ COOCH ₂ ) ₄ C, (C ₁₃ H ₂₇ SCH ₂ C
H ₂ COOCH ₂ ) ₄ C, (C ₁₄ H ₂₉ SCH ₂ CH ₂ COO
CH ₂ ) ₄ C, (C ₁₅ H ₃₁ SCH ₂ CH ₂ COOCH ₂ )
₄ C, (C ₁₆ H ₃₃ SCH ₂ CH ₂ COOCH ₂ ) ₄ C, (C
₁₇ H ₃₅ SCH ₂ CH ₂ COOCH ₂ ) ₄ C, (C ₁₈ H ₃₇ SC
H ₂ CH ₂ COOCH ₂ ) ₄ C, (C ₁₉ H ₃₉ SCH ₂ CH ₂ C
OOCH ₂ ) ₄ C, (C ₂₀ H ₄₁ SCH ₂ CH ₂ COOC
H ₂ ) ₄ C or mixtures thereof, especially (C _{12
H 25 SCH 2 CH 2 COOCH 2} ) 4 C is preferred.

One of the compounds included in the phosphite which is the component (III-2) is represented by the following general formula (5). In _{^{(R 17 O) m -P- (}} OR 18) 3-m (5) (5) formula, R ¹⁷ is a linear or branched alkyl group having 4 to 20 carbon atoms, R ¹⁸ is phenyl Group or carbon number 1
The alkylphenyl group having 20 alkyl groups, m is 0 to 3. Specific examples of R ¹⁷ include n-butyl group, isobutyl group, sec-butyl group, tert-butyl group,
Straight-chain or branched pentyl group, straight-chain or branched hexyl group, straight-chain or branched heptyl group, straight-chain or branched octyl group, straight-chain or branched nonyl group, straight-chain or branched decyl group, straight-chain Or a branched undecyl group, a straight chain or branched dodecyl group, a straight chain or branched tridecyl group, a straight chain or branched tetradecyl group, a straight chain or branched pentadecyl group, a straight chain or branched hexadecyl group, a straight chain or branched chain A branched heptadecyl group, a linear or branched octadecyl group, a linear or branched nonadecyl group, a linear or branched icosyl group,
Among these, an octyl group such as a 2-ethylhexyl group and a decyl group are particularly preferable. Specific examples of R ¹⁸ include phenyl group, methylphenyl group, dimethylphenyl group, ethylphenyl group, diethylphenyl group, n-propylphenyl group, di-n-propylphenyl group, isopropylphenyl group, diisopropylphenyl group, n-butyl. Phenyl group, di-n-butylphenyl group, isobutylphenyl group,
Diisobutylphenyl group, sec-butylphenyl group,
Disec-butylphenyl group, tert-butylphenyl group, ditert-butylphenyl group, (linear or branched pentyl) phenyl group, di (linear or branched pentyl) phenyl group, (linear or branched hexyl ) Phenyl group, di (linear or branched hexyl) phenyl group, (linear or branched heptyl) phenyl group, di (linear or branched heptyl) phenyl group, (linear or branched octyl) phenyl group, A di (linear or branched octyl) phenyl group,
(Linear or branched nonyl) phenyl group, di (linear or branched nonyl) phenyl group, (linear or branched decyl) phenyl group, di (linear or branched decyl) phenyl group,
(Linear or branched undecyl) phenyl group, di (linear or branched undecyl) phenyl group, (linear or branched dodecyl) phenyl group, di (linear or branched dodecyl) phenyl group, (linear or branched Branched tridecyl) phenyl group,
Di (linear or branched tridecyl) phenyl group, (linear or branched tetradecyl) phenyl group, di (linear or branched tetradecyl) phenyl group, (linear or branched pentadecyl) phenyl group, di (linear chain) Or a branched pentadecyl) phenyl group. (Linear or branched hexadecyl) phenyl group, di (linear or branched hexadecyl) phenyl group, (linear or branched heptadecyl) phenyl group, di (linear or branched heptadecyl) phenyl group, (linear or branched A branched octadecyl) phenyl group, a di (linear or branched octadecyl) phenyl group,
(Straight or branched nonadecyl) phenyl group, di (straight or branched nonadecyl) phenyl group, (straight or branched icosyl) phenyl group, di (straight or branched icosyl) phenyl group, Of these, a phenyl group, a (linear or branched nonyl) phenyl group, and a di (linear or branched nonyl) phenyl group are particularly preferable. Specific examples of the phosphites represented by the general formula (5) include nonylphenyl-bis (dinonylphenyl) phosphite, tris (nonylphenyl) phosphite, 2-ethylhexyl-diphenylphosphite, decyl- Diphenyl phosphite, tridecyl phosphite, triphenyl phosphite or mixtures thereof can be mentioned.

Other compounds included in the phosphite which is the component (III-2) can be represented by the following general formula (6). ((R ¹⁹ O) ₂ P (OPh)) ₂ C (CH ₃ ) ₂ (6) (6) In the formula, R ¹⁹ represents a straight-chain or branched alkyl group having 12 to 15 carbon atoms, Ph represents a phenyl group. R
Specific examples of ¹⁹ include a straight chain or branched dodecyl group, a straight chain or branched tridecyl group, a straight chain or branched tetradecyl group, and a straight chain or branched pentadecyl group. Specific examples of the phosphite represented by the general formula (11) include ((C ₁₂ H ₂₅ O) ₂ P (OPh)) ₂ C (CH ₃ ) ₂ ,
((C ₁₃ H ₂₇ O) ₂ P (OPh)) ₂ C (CH ₃ ) ₂ ,
((C ₁₄ H ₂₉ O) ₂ P (OPh)) ₂ C (CH ₃ ) ₂ ,
((C ₁₅ H ₃₁ O) ₂ P (OPh)) ₂ C (CH ₃ ) ₂ or mixtures thereof.

One of the compounds contained in the dithiophosphates as the component (III-3) is zinc dihydrocarbyl dithiophosphate represented by the following general formula (7).

[Chemical 4] In the formula (7), R ²⁰ , R ²¹ , R ²² and R ²³ may be the same or different and each have a linear or branched alkyl group having 2 to 18 carbon atoms, preferably 3 to 8 carbon atoms, or An aryl group having 6 to 24 carbon atoms is shown. Specific examples of R ²⁰ , R ²¹ , R ²² and R ²³ include ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group and s.
ec-butyl group, tert-butyl group, straight chain or branched pentyl group, straight chain or branched hexyl group, straight chain or branched heptyl group, straight chain or branched octyl group, straight chain or branched nonyl group, Straight chain or branched decyl group, straight chain or branched undecyl group, straight chain or branched dodecyl group, straight chain or branched tridecyl group, straight chain or branched tetradecyl group,
Alkyl groups such as linear or branched pentadecyl groups, linear or branched hexadecyl groups, linear or branched heptadecyl groups, linear or branched octadecyl groups; and phenyl groups, ethylphenyl groups, propylphenyl groups, isopropylphenyl Group, butylphenyl group, pentylphenyl group, hexylphenyl group, heptylphenyl group, octylphenyl group, 2-ethylhexylphenyl group, nonylphenyl group, decylphenyl group, undecylphenyl group, dodecylphenyl group, tridecylphenyl group, Examples of the aryl group include a tetradecylphenyl group, a pentadecylphenyl group, a hexadecylphenyl group, a heptadecylphenyl group, and an octadecylphenyl group. Specific examples of the zinc dihydrocarbyl dithiophosphate represented by the general formula (7) include zinc diethyldithiophosphate, zinc di-n-propyldithiophosphate, zinc diisopropyldithiophosphate, zinc di-n-butyldithiophosphate, zinc diisobutyldithiophosphate, Zinc disec-butyldithiophosphate,
Zinc ditert-butyl dithiophosphate, zinc di (linear or branched pentyl) dithiophosphate, zinc di (linear or branched hexyl) dithiophosphate, zinc di (linear or branched heptyl) dithiophosphate, di (direct Chain or branched octyl) zinc dithiophosphate, zinc di (linear or branched nonyl) dithiophosphate, zinc di (linear or branched decyl) dithiophosphate, zinc di (linear or branched undecyl) dithiophosphate, di Zinc (straight or branched dodecyl) dithiophosphate, Zinc di (straight or branched tridecyl) dithiophosphate, Zinc di (straight or branched tetradecyl) dithiophosphate, Zinc di (straight or branched pentadecyl) dithiophosphate Zinc di (linear or branched hexadecyl) dithiophosphate, Zinc di (linear or branched octadecyl) dithiophosphate, diphenyldithio Phosphate zinc, diethyl phenyl zinc dithiophosphate, dipropyl phenyl zinc dithiophosphate, diisopropylphenyl zinc dithiophosphate, dibutyl phenyl zinc dithiophosphate, dipentyl phenyl zinc dithiophosphate, dihexyl phenyl zinc dithiophosphate,
Zinc diheptylphenyldithiophosphate, zinc dioctylphenyldithiophosphate, zinc di2-ethylhexylphenyldithiophosphate, zinc dinonylphenyldithiophosphate, zinc didecylphenyldithiophosphate, zinc diundecylphenyldithiophosphate, zinc didodecylphenyldithiophosphate, Zinc ditridecyl phenyldithiophosphate,
Mention may be made of zinc ditetradecylphenyldithiophosphate, zinc dipentadecylphenyldithiophosphate, zinc dihexadecylphenyldithiophosphate, zinc diheptadecylphenyldithiophosphate, zinc dioctadecylphenyldithiophosphate or mixtures thereof.

Another compound contained in the dithiophosphates as the component (III-3) is dihydrocarbyl dithiophosphate represented by the following general formula (8).

[Chemical 5] In the formula (8), R ²⁴ , R ²⁵ , R ²⁶ and R ²⁷ may be the same or different and each have a linear or branched alkyl group having 2 to 18 carbon atoms, preferably 3 to 8 carbon atoms, or A represents an aryl group having 6 to 24 carbon atoms, A is S, SS or S
Shows the -CH ₂ -S. Specific examples of R ²⁴ , R ²⁵ , R ²⁶ and R ²⁷ include ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, straight chain or branched chain. A branched pentyl group,
Straight-chain or branched hexyl group, straight-chain or branched heptyl group, straight-chain or branched octyl group, straight-chain or branched nonyl group, straight-chain or branched decyl group, straight-chain or branched undecyl group, straight-chain Or a branched dodecyl group, a straight chain or branched tridecyl group, a straight chain or branched tetradecyl group, a straight chain or branched pentadecyl group, a straight chain or branched hexadecyl group,
Alkyl group such as linear or branched heptadecyl group, linear or branched octadecyl group; and phenyl group, ethylphenyl group, propylphenyl group, isopropylphenyl group, butylphenyl group, pentylphenyl group, hexylphenyl group, heptylphenyl group Group, octylphenyl group, 2-ethylhexylphenyl group, nonylphenyl group, decylphenyl group, undecylphenyl group, dodecylphenyl group, tridecylphenyl group, tetradecylphenyl group, pentadecylphenyl group, hexadecylphenyl group, hepta An aryl group such as a decylphenyl group or an octadecylphenyl group can be used.

One of the compounds contained in the dithiocarbamate which is the component (III-4) is zinc dihydrocarbyl dithiocarbamate represented by the following general formula (9).

[Chemical 6] In formula (6), R ²⁸ , R ²⁹ , R ³⁰ and R ³¹ may be the same or different and each have a linear or branched alkyl group having 2 to 18 carbon atoms, preferably 3 to 8 carbon atoms, or An aryl group having 6 to 24 carbon atoms is shown. Specific examples of R ²⁸ , R ²⁹ , R ³⁰ and R ³¹ include ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s
ec-butyl group, tert-butyl group, straight chain or branched pentyl group, straight chain or branched hexyl group, straight chain or branched heptyl group, straight chain or branched octyl group, straight chain or branched nonyl group, Straight chain or branched decyl group, straight chain or branched undecyl group, straight chain or branched dodecyl group, straight chain or branched tridecyl group, straight chain or branched tetradecyl group,
Alkyl groups such as linear or branched pentadecyl groups, linear or branched hexadecyl groups, linear or branched heptadecyl groups, linear or branched octadecyl groups; and phenyl groups, ethylphenyl groups, propylphenyl groups, isopropylphenyl Group, butylphenyl group, pentylphenyl group, hexylphenyl group, heptylphenyl group, octylphenyl group, 2-ethylhexylphenyl group, nonylphenyl group, decylphenyl group, undecylphenyl group, dodecylphenyl group, tridecylphenyl group, Examples of the aryl group include a tetradecylphenyl group, a pentadecylphenyl group, a hexadecylphenyl group, a heptadecylphenyl group, and an octadecylphenyl group. Specific examples of the zinc dihydrocarbyl dithiocarbamate represented by the general formula (9) include zinc diethyldithiocarbamate, zinc di-n-propyldithiocarbamate, zinc diisopropyldithiocarbamate, zinc din-butyldithiocarbamate, zinc diisobutyldithiocarbamate, Zinc disec-butyldithiocarbamate, dite
Zinc rt-butyldithiocarbamate, zinc di (linear or branched pentyl) dithiocarbamate, zinc di (linear or branched hexyl) dithiocarbamate, zinc di (linear or branched heptyl) dithiocarbamate, di (linear) Or branched octyl) zinc dithiocarbamate, zinc di (linear or branched nonyl) dithiocarbamate, zinc di (linear or branched decyl) dithiocarbamate, zinc di (linear or branched undecyl) dithiocarbamate, di ( Linear or branched dodecyl) zinc dithiocarbamate,
Zinc di (linear or branched tridecyl) dithiocarbamate, Zinc di (linear or branched tetradecyl) dithiocarbamate, Zinc di (linear or branched pentadecyl) dithiocarbamate, Di (linear or branched hexadecyl) dithiocarbamic acid Zinc, zinc di (linear or branched heptadecyl) dithiocarbamate, zinc di (linear or branched octadecyl) dithiocarbamate, zinc diphenyldithiocarbamate, zinc diethylphenyldithiocarbamate, zinc dipropylphenyldithiocarbamate,
Zinc diisopropylphenyldithiocarbamate, zinc dibutylphenyldithiocarbamate, zinc dipentylphenyldithiocarbamate, zinc dihexylphenyldithiocarbamate, zinc diheptylphenyldithiocarbamate, zinc dioctylphenyldithiocarbamate, zinc di2-ethylhexylphenyldithiocarbamate, dinonylphenyldithiocarbamine Zinc acid, zinc didecylphenyldithiocarbamate, zinc diundecylphenyldithiocarbamate, zinc didodecylphenyldithiocarbamate, zinc ditridecylphenyldithiocarbamate, zinc ditetradecylphenyldithiocarbamate, zinc dipentadecylphenyldithiocarbamate, dihexadecyl Zinc phenyldithiocarbamate, diheptadecyl Zinc phenyl dithiocarbamate,
Mention may be made of zinc dioctadecylphenyldithiocarbamate or mixtures thereof.

Another compound included in the dithiocarbamate which is the component (III-4) is dihydrocarbyl dithiocarbamate represented by the following general formula (10).

[Chemical 7] In the formula (10), R ³² , R ³³ , R ³⁴ and R ³⁵ may be the same or different and each have a linear or branched alkyl group having 2 to 18 carbon atoms, preferably 3 to 8 carbon atoms, or an aryl group having 6 to 24 carbon atoms, B is S, shows the S-S or S-CH ₂ -S. Specific examples of R ³² , R ³³ , R ³⁴ and R ³⁵ include ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, straight chain or A branched pentyl group,
Straight-chain or branched hexyl group, straight-chain or branched heptyl group, straight-chain or branched octyl group, straight-chain or branched nonyl group, straight-chain or branched decyl group, straight-chain or branched undecyl group, straight-chain Or a branched dodecyl group, a straight chain or branched tridecyl group, a straight chain or branched tetradecyl group, a straight chain or branched pentadecyl group, a straight chain or branched hexadecyl group,
Alkyl group such as linear or branched heptadecyl group, linear or branched octadecyl group; and phenyl group, ethylphenyl group, propylphenyl group, isopropylphenyl group, butylphenyl group, pentylphenyl group, hexylphenyl group, heptylphenyl group Group, octylphenyl group, 2-ethylhexylphenyl group, nonylphenyl group, decylphenyl group, undecylphenyl group, dodecylphenyl group, tridecylphenyl group, tetradecylphenyl group, pentadecylphenyl group, hexadecylphenyl group, hepta An aryl group such as a decylphenyl group or an octadecylphenyl group can be used.

Components [II] in the lubricating oil composition of the present invention
The content of [I] is, based on the total amount of the lubricating oil composition, a lower limit value of 0.1% by mass, preferably 0.2% by mass, while an upper limit value thereof is 5.0% by mass, preferably 2%. It is 0.0 mass%. When the content of the component [III] is less than 0.1% by mass based on the total amount of the lubricating oil composition, the effect obtained by blending the component [III] is not sufficient, while the upper limit is the lubricating oil composition. If the total amount of the substances exceeds 5.0% by mass, it is economically disadvantageous and therefore not preferable.

The lubricating oil composition of the present invention has an excellent antioxidative sustaining effect as it is, but for the purpose of further enhancing various performances thereof, known lubricating oil additives may be used alone or in combination of several kinds. It can be used in different forms. Specific examples of these known additives include phenol-based, amine-based, sulfur-based, zinc dithiophosphate-based, phenothiazine-based antioxidants; alkenyl succinic acid, alkenyl succinic acid ester, polyhydric alcohol ester. Rust inhibitors such as petroleum sulfonate and dinonylnaphthalene sulfonate; antiwear agents such as phosphoric acid ester, sulfurized oil, sulfide, zinc dithiophosphate, extreme pressure agents; aliphatic alcohol, fatty acid, aliphatic amine, aliphatic amine Friction reducing agents such as salts and fatty acid amides;
Metal-based detergents such as alkaline earth metal sulfonates, alkaline earth metal phenates, alkaline earth metal salicylates, alkaline earth metal phosphonates; ashless dispersants such as succinimides, succinic acid esters and benzylamines; methyl silicone, fluoro Antifoaming agent such as silicone; viscosity index improver such as polymethacrylate, polyisobutylene, olefin copolymer, polystyrene,
Examples include pour point depressants. The amount of these additives added is arbitrary, but normally the content of the defoaming agent is 0.0005 to 1% by weight, and the content of the viscosity index improver is 1 to 30% by weight based on the total amount of the lubricating oil composition. %, The content of metal deactivator is 0.005 to 1% by weight, and the content of other additives is 0.1 to 15% by weight, respectively. The lubricating oil composition of the present invention is particularly preferably used as a turbine oil, but in addition, engine oil such as gasoline engine oil and diesel engine oil; automotive gear oil (automatic transmission oil, manual transmission oil, differential) Oil) and gear oils such as industrial gear oils; hydraulic oils; compressor oils; refrigerating machine oils; cutting oils, plastic working oils (rolling oil, press oil, forging oil, drawing oil, drawing oil, punching oil, etc.), It is also preferably used in various lubricating oils such as metal working oils such as heat treatment oils and electric discharge machining oils; sliding guide surface oils; bearing oils; rust preventive oils; heat carrier oils.

[0024]

EXAMPLES The contents of the present invention will be described more specifically below with reference to Examples and Comparative Examples, but the present invention is not limited to these. Examples 1 to 9 and Comparative Examples 1 to 3 Lubricating oil compositions according to the present invention were prepared according to the compositions shown in Table 1. For comparison, a lubricating oil composition having the composition shown in Table 1 was prepared also when the component [II] was not used (Comparative Examples 1 and 2) and when the component [III] was not used (Comparative Example 3). . The components used to prepare each lubricating oil composition are as follows. [I] Component A: Solvent refined paraffinic mineral oil having a kinematic viscosity at 40 ° C. of 32 mm ² / s and a total aromatic content of 25% by mass B: Kinematic viscosity at 40 ° C. of 32 mm ² / s and a total aromatic content 5% by mass of hydrocracked and refined paraffinic mineral oil C: 1-decene oligomer hydride having a number average molecular weight of 480 (kinematic viscosity 31 mm ² / s (@ 40 ° C.)) [II] Component D:

[Chemical 8] E:

[Chemical 9] Component [III] : K: dilauryl thiodipropionate (dilauryl thiodipropionate) L: trinonylphenyl phosphite (trinonylphenyl phosphite) M: zinc dioctyldithiophosphate N: zinc dipentyldithiocarbamate Prepared Regarding each lubricating oil composition, JIS K 25
14 Lubricating oil oxidation stability test (oxidation stability test I) specified in 3.1 and rotary cylinder type oxidation stability test (oxidation stability test specified in JIS K 25143.3)
II) was performed and the time from the start of the test to the end was measured. In both of the oxidation stability tests I and II, the test temperature was 150 ° C. In the oxidation stability test I, the test was conducted under air blowing conditions, and in the oxidation stability test II, pure oxygen was added to 6.
The test was carried out by pressurizing and sealing to 3 kgf / cm ² . In the oxidation stability test I, the end point was the point when the total acid value of the sample oil reached 2 mgKOH / g. Table 1 shows the test results of the lubricating oil compositions of the examples, and Table 2 shows the test results of the lubricating oil compositions of the comparative examples.

[0025]

[Table 1]

[0026]

[Table 2]

As is clear from the comparison of Tables 1 and 2, the compositions of Examples 1 to 9 according to the present invention were tested under two kinds of oxidation tests under different test conditions.
It shows very good oxidative stability. In particular, the compositions of Examples 2 and 3 using the particular base oil as the base oil are superior to the composition of Example 1. On the other hand,
The compositions of Comparative Examples 1 and 2 which did not use the component [II] were greatly inferior in oxidation stability in any oxidation test. Further, the composition of Comparative Example 3 not using the component [III] is
Although it shows better oxidative stability than the compositions of Comparative Examples 1 and 2, it is inferior in oxidative stability to the compositions of Examples containing all the components [I] to [III]. As described above, the effect of using the components [I], [II] and [III] together is clear.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI C10M 135: 18) C10M 135: 20 (C10M 141/08 137: 02 129: 76 C10M 137: 10 Z 135: 20) 101: 02 (C10M 141/10 105: 06 129: 76 107: 02 137: 02) C10N 20:02 (C10M 141/10 20:04 129: 76 30:08 137: 10) 30:10 (C10M 169/04 40: 12 101: 02 105: 06 107: 02 129: 76 135: 18 135: 20 137: 02 137: 10) C10N 20:02 20:04 30:08 30:10 40:12 (72) Inventor Toshio Yoshida Yokohama Central Chiba Research Institute, Japan Petroleum Co., Ltd. (56) References JP-A-7-258677 (JP, A) JP-A-7-150175 (JP, A) JP-A-5-179275 (JP , A) JP 2-284994 (JP, A) JP 62-89796 (JP, A) JP 6-93281 (JP, A) JP 5-70788 (JP, A) Kai 61-148287 (JP, A) JP 61-254540 (JP, A) JP 9-183991 (JP, A) JP 9-183994 (JP, A) JP 60-156644 ( JP, A) JP 62-298557 (JP, A) JP 57-48944 (JP, A) JP 8-157848 (JP, A) JP 8-157854 (JP, A) (58) ) Fields investigated (Int.Cl. ⁷ , DB name) C10M 141/08-141/10 C10M 101/02 C10M 105/06 C10M 107/02-107/18 C10M 129/76 C10M 135/18-135/30 C10M 137/02 C10M 137/10 C10M 169/04 C10N 20:02-20:04 C10N 30:08-30:10 C10N 40:12-40:13

Claims (2)

(57) [Claims] 1. [I] a lubricating base oil and, based on the total amount of the composition, [II] 3-methyl-represented by the following general formula (1):
The 5-tert-butyl-4-hydroxyphenyl group-substituted fatty acid ester 0.1 to 5.0 wt%, and ## STR1 ## [In the formula (1), R ¹ represents an alkylene group having 1 to 6 carbon atoms, and R ² represents an alkyl group having 4 to 18 carbon atoms. ] [II
I] 0.1 to 5 mass% of one or more compounds selected from the following (III-1) to (III-4) : (III-1) represented by the following general formula (2) Being sulphid
A sulfide represented by the following general formula (3), and
Selected from the group consisting of sulfides represented by general formula (4)
At least one sulfide, R ¹² —S _g —R ¹³ (2) [wherein R ¹² and R ¹³ are the same or different;
Well, alkyl group having 1 to 22 carbon atoms and carbon number 6 respectively
~ 20 aryl group, C7-20 alkylaryl
Group or an arylalkyl group having 7 to 20 carbon atoms
And g represents an integer of 1 to 5. ] In _{^{R 14 OCO (CH 2) h}} S j (CH 2) k COOR 15 (3) [(3) equation, even if R ¹⁴ and R ¹⁵ are identical or different
Well, each represents an alkyl group having 2 to 20 carbon atoms, h
And k may be the same or different and each is 2 to 5
Is an integer, and j is 1 or 2. ] In _{^{(R 16 SCH 2 CH 2 COOCH}} 2) 4 C (4) [(4) formula, R ¹⁶ is shows an alkyl group having 8 to 20 carbon atoms
You ] (III-2) phosphites, (III-3) dithiophosphates, and (III-4) dithiocarbamates are contained, The lubricating oil composition characterized by the above-mentioned. 2. A lubricating base oil of component [I] has the following (I-
The lubricating oil composition according to claim 1, which is one or two or more lubricating base oils selected from the components 1) to (I-3). (I-1) Mineral oil having a kinematic viscosity at 40 ° C. of 5 to 200 mm ² / s and a total aromatic content of 15% by weight or less (I-2) a polymer of an olefin having 2 to 16 carbon atoms or The hydride thereof having a number average molecular weight of 250 to 4000 (I-3) having 1 to 4 alkyl groups having 1 to 40 carbon atoms,
And an alkylbenzene whose alkyl group has a total carbon number of 6 to 40