JPH09263783A - Lubricating oil composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a lubricating oil composition having excellent antioxidant properties and sludge formation preventive properties and does not deteriorate in performances even when used for a long time under high-temperature conditions by mixing a lube base oil with a specified alkyphenol in a specified ratio. SOLUTION: This composition is obtained by mixing 100 pts.wt. lube base oil with 0.1-5 pts.wt., desirably 0.2-3 pts.wt. 2-t-butyl-4-alkyloxymethyl-6- alkylphenol represented by the formula (wherein R<1> is a 1-4C alkyl; and R<2> is a 1-24C alkyl or alkenyl). The lube base oil is desirably at least one member selected among mineral oils (e.g. hydrocracked paraffinic mineral oils) having a kinematic viscosity of 5-200mm<2> /s and a total aromatic content of 15mass% or below, polymers of a 2-16C olefin of hydrogenation products thereof and having a number-avearge molecular weight of 250-4,000 (e.g. hydrogenated 1- decene oligomer) and alkylbenzenes each having 1-4 1-40C alkyls and the total number of carbon atoms of the alkyls of 6-40.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a lubricating oil composition which contains a lubricating base oil and a small amount of a phenolic compound and is excellent in oxidation stability and sludge formation preventing property.

[0002]

2. Description of the Related Art It has been conventionally known that 2,6-di-tert-butyl-p-cresol (DBPC) has excellent performance as an antioxidant for lubricating oil. The agents are frequently used in various lubricating oils, especially turbine oils. However, when the lubricating oil containing DBPC is used for a long time under high temperature conditions such as turbine oil, the concentration in the lubricating oil is lowered due to the scattering or evaporation of DBPC, and therefore the antioxidant property is prolonged. There was a problem that it could not be maintained. As a lubricant stabilizer other than DBPC, there is a sterically hindered hydroxyphenylcarboxylic acid ester described in JP-A-60-156644. According to the description in this patent publication, a sterically hindered hydroxyphenylcarboxylic acid ester is said to be useful as a stabilizer for synthetic organic polymers, animal and vegetable oils, hydrocarbons, lubricating oils, etc.
5-di-tert-butyl-4-hydroxyphenyl)
Propionate esters are mentioned. (3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid ester is scattered during use compared to DBPC.
Although it is excellent in that it has less evaporation, it is inferior in its antioxidative ability to DBPC, and was not satisfactory as a substitute for DBPC.

[0003]

SUMMARY OF THE INVENTION One of the objects of the present invention is to eliminate various problems pointed out in the lubricating oil composition containing the conventional antioxidant as described above. Another object of the present invention is to provide a new antioxidant for a lubricating oil having performance superior to or inferior to that of DBPC, and obtained by blending the antioxidant with a lubricating base oil. However, it is an object of the present invention to provide a lubricating oil composition which is excellent in the antioxidant property and the sludge generation preventive property and whose performance does not deteriorate even when used for a long time under high temperature conditions.

[0004]

The lubricating oil composition of the present invention comprises: [II] 2-tert-type represented by the following general formula (1) with respect to 100 parts by weight of a lubricating base oil. Butyl-4
-Alkyloxymethyl-6-alkylphenol 0.
1 to 5 parts by weight is blended.

Embedded image [In the formula, R ¹ represents an alkyl group having 1 to 4 carbon atoms, and R ²
Represents an alkyl group or an alkenyl group having 1 to 24 carbon atoms. ]

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the contents of the present invention will be described in more detail. The lubricating base oil that is the component [I] of the present invention is not particularly limited, and any mineral oil or synthetic system can be used as long as it is a commonly used base oil for lubricating 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 that have been refined individually or in combination of two or more may be used. Examples of synthetic lubricating base oils include poly-α-olefins (polybutene, 1-
Octene oligomer, 1-decene oligomer, etc.), alkylbenzene, alkylnaphthalene, diester (ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, di-2-ethylhexyl sebacate, etc.), polyester (trimerit) Acid ester), polyol ester (trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate, pentaerythritol pelargonate, etc.), polyoxyalkylene glycol, dialkyldiphenyl ether, polyphenyl ether, etc. Can be used. 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 is not particularly limited in its viscosity, but in general, it is preferable that the kinematic viscosity (referring to the kinematic viscosity at 40 ° C., the same applies hereinafter) is 1 to 1000 mm ² / s, It is more preferably 5 to 800 mm ² / s. However, 2-tert- which is the [II] component of the present invention
The lubricating base oil of the present invention has the following properties in that the lubricating oil composition obtained in combination with butyl-4-alkyloxymethyl-6-alkylphenol exhibits excellent antioxidant properties and sludge formation preventing properties. Show (I-1)
The oil is preferably one or more oils selected from the component (I-3). (I-1) A mineral oil having a kinematic viscosity of 5 to 200 mm ² / s and a total aromatic content of 15% by mass or less. (I-2) A polymer of an olefin having 2 to 16 carbon atoms or a hydride thereof, having a number average molecular weight of 250 to 40.
Those in the range of 00. (I-3) An alkylbenzene having 1 to 4 alkyl groups having 1 to 40 carbon atoms and having 6 to 40 total carbon atoms in the alkyl groups. The lower limit of the kinematic viscosity of the component (I-1) is 5 mm ² / s, preferably 10 mm ² / s, and the upper limit is 200 mm ² / s, preferably 100 mm ² / s. (I-1) component has a kinematic viscosity of 5 m
When it is less than m ² / s, lubricity may be deteriorated due to insufficient oil film formation, and evaporation loss of the base oil under high temperature conditions may be large. On the other hand, when the kinematic viscosity of the component (I-1) exceeds 200 mm ² / s, the fluid resistance increases, and the frictional resistance at the lubricated portion may increase. It is important that the upper limit of the total aromatic content of the component (I-1) is 15% by mass, preferably 10% by mass, more preferably 7% by mass. When the total aromatic content exceeds 15% by mass, (I-1) component and [II]
The synergistic effect with the components may not be obtained so much, and there is a possibility that the excellent antioxidant property and sludge generation preventive property may not be exhibited. 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. The total aromatic content is preferably 2% by mass or more because the solubility of sludge generated in 1 tends to be poor. The total aromatic content referred to in the present invention means ASTM D 254.
9 "Standard Test Method for Separatio"
n of Representative Aromatics and Nonaromatics Frac
tions of High-Boiling Oils by Elution Chromatograp
aromatics (aromatics fracti
on) content, and usually, in this aromatic fraction, alkylbenzene, alkylnaphthalene, anthracene, phenanthrene, and their alkylated products,
Examples include compounds in which four or more benzene rings are fused, or compounds having a heteroaromatic such as pyridines, quinolines, phenols, and naphthols. (I-
The component 1) can be produced by any known method.
For example, distillate oil of paraffin-based crude oil and / or mixed base crude oil by atmospheric distillation; vacuum distillation distillate (WVGO) of paraffin-based crude oil and / or mixed base crude oil under atmospheric distillation residue (WVGO); and / Or mild hydrocracking (MHC) treated oil (HIX);
A mixed oil of two or more kinds of oil selected from
Or a deasphalted oil (DAO); a mild hydrocracking (MHC) treated oil; a mixed oil of two or more kinds of oil selected from
This raw material oil can be obtained as it is, or the lubricating oil fraction recovered from this raw material oil can be obtained by refining it by an ordinary refining method and recovering the lubricating oil fraction. 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 purification with acid clay or activated clay, (5) chemical (acid or alkali) purification such as sulfuric acid cleaning, caustic soda cleaning, etc. One or more of these may be employed in the present invention 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 has a kinematic viscosity of 5 to 200 at 40 ° C. of itself or an arbitrary mixture thereof.
Any mineral oil or any mixture thereof can be used as the component (I-1) of the present invention as long as it is mm ² / s and the total aromatic content is 15% by mass or less. When the base oil in the lubricating oil composition of the present invention is composed only of mineral oil, the raw material oil selected from the above is recovered as it is or from this raw material oil because of its excellent synergistic effect with the component [II]. The lubricating oil fraction thus obtained is hydrocracked to recover the product as it is, or the lubricating oil fraction is recovered therefrom.
Next, perform dewaxing treatment such as solvent dewaxing and contact dewaxing,
Thereafter, the component (I-1) produced by solvent refining treatment or solvent refining treatment followed by dewaxing treatment such as solvent dewaxing or contact dewaxing is preferably 50 on the basis of the total amount of base oil. Mass% or more, more preferably 70 mass% or more,
It is particularly preferable to use 80% by mass or more. The conditions for hydrocracking referred to herein are arbitrary, but usually, in the presence of a hydrocracking catalyst, the total pressure is 6 to 25 MPa.
a, temperature 350 ~ 500 ℃, LHSV0.1 ~ 2.0hr
^Under the reaction conditions such as ^-1 , the hydrocracking conditions are adopted so that the decomposition rate is 40% by mass or more. Although any hydrocracking catalyst can be used, usually, for example, molybdenum,
Chrome, tungsten, vanadium, platinum, nickel,
Copper, iron, cobalt, oxides and / or sulfides of these, or mixtures thereof are used. These catalysts may be used as they are, or may be used in a form supported on a carrier such as silica-alumina, activated alumina and zeolite.

The olefin constituting the component (I-2) is an olefin having 2 to 16 carbon atoms, preferably 2 to 12 carbon atoms, and the olefin is a so-called α-olefin having a double bond at the terminal. However, it may be a so-called internal olefin having the double bond inside. Further, it may be a linear olefin or a branched olefin. Examples of such olefins include ethylene, propylene, 1-butene, 2-
Butene, isobutene, linear or branched pentene (including α-olefins, internal olefins), linear or branched hexene (including α-olefins, internal olefins), linear or branched Heptene (including α-olefins and internal olefins), linear or branched octene (including α-olefins and internal olefins), linear or branched nonene (α-olefins,
Internal olefins), linear or branched decene (α-olefins, including internal olefins), linear or branched undecene (α-olefins, including internal olefins), linear or Branched dodecene (including α-olefins and internal olefins), linear or branched tridecene (including α-olefins and internal olefins), linear or branched tetradecene (α-olefins, Internal olefins), linear or branched pentadecenes (α-olefins, including internal olefins), linear or branched hexadecenes (α-olefins, including internal olefins), and mixtures thereof. Etc., but especially ethylene, propylene, 1-
Butene, 2-butene, isobutene, 1-octene, 1-
Decene, 1-dodecene and mixtures thereof are preferably used. The component (I-2) of the present invention comprises a polymer of the above-mentioned olefin or a hydride thereof, and the polymer here includes not only one type of olefin homopolymer but also two or more types of olefin. A random copolymer of
Copolymers such as alternating copolymers and block copolymers are included. The olefin homopolymer or copolymer usually contains a double bond.
As the component 2), it is preferable to use a homopolymer or copolymer obtained by hydrogenating the double bond from the viewpoint of excellent heat / oxidation stability. The method for producing the olefin polymer as the component (I-2) is arbitrary and is not limited in any way, but generally, it is an organic peroxide catalyst such as benzoyl peroxide or the like by an uncatalyzed thermal reaction; aluminum chloride. , Aluminum chloride-polyhydric alcohol type, aluminum chloride-titanium tetrachloride type, aluminum chloride-alkyltin halide type, boron fluoride and other Friedel-Crafts type catalysts; organic aluminum chloride-titanium tetrachloride type, organic aluminum-tetrachloride type Ziegler type catalysts such as titanium type; metallocene type catalysts such as aluminoxane-zirconocene type and ionic compound-zirconocene type; known catalyst systems such as aluminum chloride-base type and Lewis acid complex type catalysts such as boron fluoride-base type Is used to homopolymerize or copolymerize the above olefins. Obtained by Rukoto. The method for obtaining the hydride of the olefin polymer is also optional, for example, by hydrogenating the olefin polymer with hydrogen in the presence of a known hydrogenation catalyst to saturate the double bond present in the olefin polymer. can get. Some catalysts can perform olefin polymerization and hydrogenation of double bonds present in the polymer in one step without going through the two-step process of polymerizing the olefin and hydrogenating the obtained polymer. is there. As the component (I-2) of the present invention, an ethylene-propylene copolymer, polybutene (butane which is a by-product during thermal decomposition of naphtha) is used because of its excellent heat / oxidation stability, viscosity-temperature characteristics, and low-temperature fluidity. Butene (mixture of 1-butene, 2-butene and isobutene)
Copolymers obtained by polymerization of fractions), 1-octene oligomers, 1-decene oligomers, 1-dodecene oligomers and hydrides thereof, and mixtures thereof are more preferably used, and ethylene-propylene copolymers are used. Hydride, polybutene hydride, 1-octene oligomer hydride, 1-decene oligomer hydride, 1-
Dodecene oligomer hydride, and mixtures thereof are particularly preferably used. At present, commercially available ethylene-propylene copolymers for lubricant base oils, synthetic oils such as polybutene and poly-α-olefin are
Usually, the double bond is already hydrogenated, and these commercially available products 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,
It is preferably 3000, more 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. The viscosity of the olefin polymer or its hydride that is the component (I-2) is not particularly limited,
Preferred kinematic viscosity 5 to 200 mm ² / s, more preferably from 10 to 100 mm ² / s.

The component (I-3) of the present invention has 1 to 40 carbon atoms.
An alkylbenzene having 1 to 4 alkyl groups and having a total carbon number of 6 to 40.
It 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 12 to 40, from the viewpoint of excellent heat and oxidation stability and availability. Preferred, having 1 to 4 alkyl groups having 1 to 30 carbon atoms, and having a total carbon number of 15 to 15
More preferably, it is 30 alkylbenzene. When an alkylbenzene in which the total number of carbon atoms in the alkyl group is less than 6 is used, 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 alkylbenzene in which the total carbon number of the alkyl group exceeds 40 is used, the fluid resistance increases, and thus the frictional resistance at the lubricated portion may increase. The alkyl group having 1 to 40 carbon atoms referred to in the component (I-3) may be linear or branched, and specific examples of such an alkyl group include a methyl group and an ethyl group. , Propyl group,
Isopropyl group, n-butyl group, isobutyl group, sec
-Butyl group, tert-butyl group, straight-chain or branched 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, direct 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 chain 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 Ntakoshiru group, straight or branched hexacosyl group, straight 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 dotriacontyl group, straight-chain or Branched tritriacontyl group, linear or branched tetratriacontyl group, linear or branched pentatriacontyl group, linear or branched hexatriacontyl group, linear or branched Examples thereof include a heptatriacontyl group, a linear or branched octatriacontyl group, a linear or branched nonatriacontyl group, and a linear or branched tetracontyl group. The alkyl group of alkylbenzene may be linear or branched, but is preferably a branched alkyl group from the viewpoint of viscosity-temperature characteristics and low-temperature fluidity, and is particularly available. From the viewpoint, a branched alkyl group derived from an olefin oligomer such as propylene, butene, and isobutylene is more preferable. The number of alkyl groups of alkylbenzene can be selected in the range of 1 to 4, but 1 or 2 is selected from the viewpoints of heat and oxidation stability and availability.
Alkylbenzenes having 4 alkyl groups,
Monoalkylbenzene, dialkylbenzene or a mixture thereof is most preferable as the component (I-3). Needless to say, the alkylbenzene which is the component (I-3) of the present invention 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. The alkylbenzene may have a single structure or a mixture of alkylbenzenes having different structures. The viscosity of the component (I-3) is not particularly limited, but the preferable kinematic viscosity is 5 to 200 mm ² / s, more preferably 10
~ 100 mm ² / s. The method for producing the component (I-3) of the present invention is arbitrary and is not particularly limited, but generally, it can be produced by the synthetic method shown below. Examples of the aromatic compound as a raw material include benzene, toluene,
Xylene, ethylbenzene, methylethylbenzene, diethylbenzene, a mixture thereof, or the like is used. 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 oils, Linear or branched olefin having 6 to 40 carbon atoms obtained by thermal decomposition of petroleum fraction, 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 converting the compound to a compound, and a mixture thereof can be used. Known alkylating catalysts for alkylation include 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.

In the lubricating oil composition of the present invention, the above-mentioned component (I-2) and / or (I-) is used as the component [I].
When the component 3) is used, the kinematic viscosity is preferably 5 to 200 mm ² / s, for the purpose of improving the swelling property of the member such as the rubber sealing material used in the place where the lubricating oil composition of the present invention is used. Is 10 to 100 mm ² / s for mineral oil base oils, ester base oils, ether base oils, and mixtures thereof,
It can be contained in an amount of 40% by mass or less, preferably 30% by mass or less, and more preferably 20% by mass or less, based on the total amount of the base oil as the component (I). The mineral oil base oil used in combination with the component (I-2) and / or the component (I-3) is not limited in its total aromatic content, and paraffin base crude oil or mixed base crude oil may be subjected to atmospheric distillation and vacuum distillation. The lubricating oil fraction thus obtained is subjected to a single refining treatment such as hydrorefining, solvent refining, dewaxing, clay refining, chemical (acid or alkali) refining,
Alternatively, it is possible to use a mineral oil-based base oil such as a paraffin-based or naphthene-based base oil having an arbitrary total aromatic content, which is refined by combining two or more arbitrary refining methods including the same or the same refining method in an arbitrary order. it can. However,
When using a mineral base oil, it is a component [II] 2
-Tert-butyl-4-alkyloxymethyl-6-
In terms of its excellent synergistic effect with alkylphenol,
After all, it is more preferable to use the component (I-1) of the present invention together. 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, ditridecyl adipate, and ditridecyl adipate. Diester oils such as -3-ethylhexyl sebacate; trimethylolpropane tricaprylate, trimethylolpropane triperargonate,
Examples thereof include polyol ester oils represented by pentaerythritol tetra (2-ethylhexanoate) and pentaerythritol tetrapelargonate; and mixtures of two or more ester base oils selected from these. Examples of the ether base oil include polyglycol oils represented by polyoxyethylene glycol, polyoxypropylene glycol, polyoxyethyleneoxypropylene glycol, polyoxybutylene glycol, etc .; monoalkyl etherified products of these polyglycol oils, Dialkyl ether compound; diphenyl ether, polyphenylene ether, and a mixture of two or more ether-based base oils selected from these.

The component [II] of the present invention is 2-tert-butyl-4-alkyloxymethyl-6-alkylphenol represented by the following general formula (1).

Embedded image In the above formula, R ¹ is a linear or branched alkyl group having 1 to 4 carbon atoms, and R ² is a linear or branched alkyl group or alkenyl group having 1 to 24 carbon atoms. Shown respectively. Specific examples of R ¹ include, for example, 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, but they are easy to synthesize. From the viewpoint of, a methyl group or a tert-butyl group is preferable. When R ² is an alkyl group, specific examples thereof include propyl groups such as methyl group, ethyl group, n-propyl group and isopropyl group; n-butyl group, isobutyl group, sec-butyl group, tert-butyl group. A butyl group such as a group; a linear or branched pentyl group; a linear or branched hexyl group; a linear or branched heptyl group; a linear or branched octyl group; a linear or branched nonyl group A linear or branched decyl group; a linear 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 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; A chain or branched tricosyl group; a straight chain or branched tetracosyl group can be mentioned. When R ² is an alkenyl group, specific examples thereof include a vinyl group, a propenyl group, an isopropenyl group, a linear or branched butenyl group, a linear or branched pentenyl group, a linear or branched hexenyl group. , A straight-chain or branched heptenyl group, a straight-chain or branched octenyl group, a straight-chain or branched nonenyl group, a straight-chain or branched decenyl group, a straight-chain or branched undecenyl group, a straight-chain or branched A branched dodecenyl group, a linear or branched tridecenyl group, a linear or branched tetradecenyl group, a linear or branched pentadecenyl group, a linear or branched hexadecenyl group,
Straight-chain or branched heptadecenyl group, straight-chain or branched octadecenyl group, straight-chain or branched octadecadienyl group, straight-chain or branched nonadecenyl group, straight-chain or branched icosenyl group, straight-chain Alternatively, a branched henicosenyl group, a linear or branched docosenyl group, a linear or branched tricosenyl group, a linear or branched tetracosenyl group, or the like can be given. The carbon number of R ² in the above general formula (1) is 2 or more in that the scattering and evaporation of the [II] component that occurs when the lubricating oil composition of the present invention is used for a long time under high temperature conditions is small. It is preferable. In consideration of the solubility in the component [I], R ² in the general formula (1) is an alkyl group having 4 to 18 carbon atoms, for example, 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 a branched decyl group, a straight-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 More preferably, it is an alkyl group such as a group, a straight chain or branched hexadecyl group, a straight chain or branched heptadecyl group, a straight chain or branched octadecyl group, and among these, a straight chain having 6 to 12 carbon atoms. It is even more preferred that it is a branched or branched alkyl group,
More preferably, it is a branched alkyl group having 6 to 12 carbon atoms. Most preferred R ² is a branched alkyl group having 8 carbon atoms such as 2-ethylhexyl group. Preferred [II] component is represented by R ¹ in the general formula (1).
Is a methyl group or a tert-butyl group, R ² is a linear or branched alkyl group having 6 to 12 carbon atoms, and particularly R ¹ is a methyl group or a tert-butyl group, R ² Is preferably a branched alkyl group having 6 to 12 carbon atoms. As a matter of course, in the present invention, one kind or two or more kinds of the compounds included in the general formula (1) can be used as the [II] component. Specific examples of preferred compounds as the component [II] in the present invention are 2-tert-butyl-4-n-hexyloxymethyl-6-methylphenol and 2-tert-butyl-
4-isohexyloxymethyl-6-methylphenol, 2-tert-butyl-4-n-heptyloxymethyl-6-methylphenol, 2-tert-butyl-
4-Isoheptyloxymethyl-6-methylphenol, 2-tert-butyl-4-n-octyloxymethyl-6-methylphenol, 2-tert-butyl-
4-isooctyloxymethyl-6-methylphenol, 2-tert-butyl-4- (2-ethylhexyl) oxymethyl-6-methylphenol, 2-ter
t-butyl-4-n-nonyloxymethyl-6-methylphenol, 2-tert-butyl-4-isononyloxymethyl-6-methylphenol, 2-tert-butyl-4-n-decyloxymethyl-6 -Methylphenol, 2-tert-butyl-4-isodecyloxymethyl-6-methylphenol, 2-tert-butyl-
4-n-undecyloxymethyl-6-methylphenol, 2-tert-butyl-4-isoundecyloxymethyl-6-methylphenol, 2-tert-butyl-4-n-dodecyloxymethyl-6-methyl Phenol, 2-tert-butyl-4-isododecyloxymethyl-6-methylphenol, 2,6-di-tert-
Butyl-4-n-hexyloxymethylphenol,
2,6-di-tert-butyl-4-isohexyloxymethylphenol, 2,6-di-tert-butyl-
4-n-heptyloxymethylphenol, 2,6-di-tert-butyl-4-isoheptyloxymethylphenol, 2,6-di-tert-butyl-4-n-octyloxymethylphenol, 2,6- The-tert
-Butyl-4-isooctyloxymethylphenol,
2,6-di-tert-butyl-4- (2-ethylhexyl) oxymethylphenol, 2,6-di-tert
-Butyl-4-n-nonyloxymethylphenol,
2,6-di-tert-butyl-4-isononyloxymethylphenol, 2,6-di-tert-butyl-4
-N-decyloxymethylphenol, 2,6-di-t
ert-Butyl-4-isodecyloxymethylphenol, 2,6-di-tert-butyl-4-n-undecyloxymethylphenol, 2,6-di-tert-butyl-4-isoundecyloxymethylphenol ,
2,6-di-tert-butyl-4-n-dodecyloxymethylphenol, 2,6-di-tert-butyl-
4-isododecyloxymethylphenol, a mixture thereof, and the like. 2-tert-butyl-4-alkyloxymethyl- which is the [II] component of the present invention
The method for producing 6-alkylphenol is arbitrary and is not particularly limited by the method for producing. For reference, one preferable example is 2-tert-butyl-4.
-Alkyloxymethyl-6-alkylphenol is
It can be obtained in the following three stages. First, 2-te
By reacting rt-butyl-6-alkylphenol with dimethylamine and formaldehyde, 2
-Tert-butyl-4-dimethylaminomethyl-6-
Obtain an alkylphenol. Next, this product is reacted with acetic anhydride to exchange the dimethylamino group with an acetoxyl group to obtain 3-tert-butyl-4-hydroxy-5-alkylbenzyl acetate. Next, this product is reacted with an aliphatic alcohol in the presence of a strongly acidic catalyst to convert the acetoxyl group into an alkoxyl group, whereby 2-tert-butyl-4-alkyloxymethyl-6-alkylphenol can be obtained. . The aliphatic alcohol referred to herein is an aliphatic alcohol having 1 to 24 carbon atoms, preferably an aliphatic alcohol having 4 to 18 carbon atoms, more preferably a branched aliphatic alcohol having 6 to 12 carbon atoms, and most preferably 2 Mention may be made of ethylhexyl alcohol. Examples of the strongly acidic catalyst used herein include perchloric acid, triphenylacetic acid, sulfuric acid, etc. Among them, perchloric acid is preferable.

The blending amount of the component [II] in the lubricating oil composition of the present invention is 0.1 part by weight, preferably 0.2 part by weight, based on 100 parts by weight of the lubricating base oil. On the other hand, the upper limit is 5 parts by weight, preferably 3 parts by weight.
When the blending amount of the component [II] is less than 0.1 part by weight based on 100 parts by weight of the lubricating base oil, the effect of improving the oxidation stability by the blending of the component [II] is insufficient, while the upper limit Is more than 5 parts by weight with respect to 100 parts by weight of the lubricating base oil,
It is not preferable because the effect of improving the oxidation stability corresponding to the blending amount cannot be obtained and it is economically disadvantageous.

The lubricating oil composition of the present invention is excellent in sustaining effects of antioxidant property and sludge formation preventing property as it is, but a known lubricating oil additive is used alone for the purpose of further enhancing various performances thereof. It can be used in the form of or a combination of several kinds. 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, etc. , Petroleum sulfonate, dinonylnaphthalene sulfonate, etc. rust inhibitor; Phosphate ester, sulfurized oil, sulfide, anti-wear agent such as zinc dithiophosphate, extreme pressure agent; 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; succinimides, succinates, benzylamines Ashless dispersants such as thiadiazole, ze Metal deactivators such as zotriazole, benzothiazole or their derivatives; antifoaming agents such as methyl silicone, fluorosilicone; viscosity index improvers such as polymethacrylate, polyisobutylene, olefin copolymers, polystyrene, pour point depressants, etc. Can be mentioned. The amount of these additives added is arbitrary, but normally, the lubricating base oil 1
The amount of the defoaming agent is 0.0005 to 1 with respect to 00 parts by weight.
Parts by weight, the content of the viscosity index improver is 1 to 30 parts by weight, the content of the metal deactivator is 0.005 to 1 part by weight, and the content of the other additives is 0.1 to 15 parts by weight, respectively. It is a department. 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.

[0012]

EXAMPLES The contents of the present invention will be described below in Examples and Comparative Examples.
Therefore, the present invention will be described in more detail below.
Are not limited.Synthesis example 1 First, with 2-tert-butyl-6-methylphenol
Contact with dimethylamine and formaldehyde
With, 2-tert-butyl-4-dimethylamino
Methyl-6-methylphenol was obtained. Then this product
And acetic anhydride by contacting
By exchanging the tyl group with an acetoxyl group, 3-
tert-butyl-4-hydroxy-5-methylbenzi
To obtain lu-acetate, 2-ethylhexyl alcohol
And acetylene in the presence of perchloric acid
A toxyl group is converted to an alkoxyl group, and 2-tert-
Butyl-4- (2-ethylhexyl) oxymethyl-6
-Methylphenol (E) was obtained.Synthesis example 2 Replacement of 2-tert-butyl-6-methylphenol
2,6-di-tert-butylphenol was used for
Synthesis was carried out in the same manner as in Synthesis Example 1 except for using 2,6-di-te.
rt-Butyl-4- (2-ethylhexyl) oxymethy
Luphenol (F) was obtained.Synthesis example 3 N-hexyl instead of 2-ethylhexyl alcohol
Synthesis was performed in the same manner as in Synthesis Example 1 except that alcohol was used.
2-tert-butyl-4-hexyloxymethyl
-6-Methylphenol (G) was obtained.Synthesis example 4 Instead of 2-ethylhexyl alcohol, n-butyl alcohol
Synthesis was performed in the same manner as in Synthesis Example 1 except that rucor was used.
2-tert-butyl-4-butyloxymethyl-
6-Methylphenol (H) was obtained.Synthesis example 5 2-Ethylhexyl Alcohol instead of Alcohol
Synthesis was performed in the same manner as in Synthesis Example 1 except that
-Tert-butyl-4-ethyloxymethyl-6-me
Cylphenol (I) was obtained.Synthesis example 6 Methyl alcohol instead of 2-ethylhexyl alcohol
Synthesis was performed in the same manner as in Synthesis Example 1 except that
-Tert-butyl-4-methyloxymethyl-6-me
Cylphenol (J) was obtained.Examples 1-15 and Comparative Examples 1-3 Preparation of various lubricating oil compositions using the components shown below
did.[I] component A: Kinematic viscosity at 40 ° C is 32 mm^Two/ s, wholly aromatic
Solvent refined paraffinic mineral oil with an amount of 25% by mass B: Kinematic viscosity at 40 ° C is 32 mm^Two/ s, wholly aromatic
Hydrocracking refined paraffinic mineral oil with an amount of 5% by mass C: Kinematic viscosity at 40 ° C is 31 mm^Two/ s, number average molecular weight
1-decene oligomer hydride of 480 D: Kinematic viscosity at 40 ° C is 32 mm^Two/ s, carbon number 12 ~
Monoalkylbenzene mixture having one alkyl group of 18
Compound[II] component E: 2-tert-butyl-4- (2-ethylhexyl
) Oxymethyl-6-methylphenol F: 2,6-di-tert-butyl-4- (2-ethyl)
Hexyl) oxymethylphenol G: 2-tert-butyl-4-hexyloxymethyl
-6-Methylphenol H: 2-tert-butyl-4-butyloxymethyl-
6-Methylphenol I: 2-tert-butyl-4-ethyloxymethyl-
6-Methylphenol J: 2-tert-butyl-4-methyloxymethyl-
6-methylphenol Other antioxidants K: 2,6-di-tert-butyl-p-cresol L: (3,5-di-tert-butyl-4-hydroxy
Phenyl) propionic acid ester For each prepared lubricating oil composition, JIS K 25
14 3.1 Ammonium oxide oxidation specified in 1993
Stability test (oxidation stability test I) and JISK 251
4 Rotating cylinder type acid specified in 3.3 (1993)
At the start of the test, the chemical stability test (oxidation stability test II) was performed.
The time from when to the end point was measured. Oxidation stability test
For both I and II, the test temperature was 150 ° C.
In constant temperature test I, the test is conducted under the condition of blowing air and oxidation
Stability test II uses pure oxygen of 6.3 kgf / cm^TwoPressurized to
It was enclosed. In the oxidation stability test I,
The end point was when the total acid value reached 2 mgKOH / g.
Table 1 shows the composition of each lubricating oil composition and the test results.

Base oil additive Oxidation stability test I Oxidation stability test II (parts by weight) (parts by weight) (hours) (minutes) Example 1 A (100) E (1) 168 207 Example 2 B (100 ) E (1) 216 579 Example 3 B (100) E (2) 264 695 Example 4 C (100) E (1) 264 643 Example 5 D (100) E (1) 216 562 Example 6 C (50) + D (50) E (1) 240 602 Example 7 A (100) F (1) 192 198 Example 8 B (100) F (1) 240 427 Example 9 C (100) F (1) 288 512 Example 10 D (100) F (1) 240 407 Example 11 B (50) + C (50) F (1) 264 460 Example 12 B (100) G (1) 192 565 Example 13 B ( 100) H (1) 192 510 Example 14 B (100) I (1) 168 430 Example 15 B (100) J (1) 168 380 Comparative Example 1 A (100) -24 50 Comparative Example 2 A (100 ) K (1) 144 185 Comparative Example 3 A (100) L (1) 168 160

As is clear from the results shown in Table 1, [I
All of the lubricating oil compositions of the present invention containing 2-tert-butyl-4-alkyloxymethyl-6-alkylphenols E to J, which are components [I], exhibit extremely excellent oxidative stability. On the other hand, Comparative Example 1 containing no antioxidant shows significantly lower oxidation stability in any oxidation stability test than that of the present invention. In addition, the lubricating oil composition of Comparative Example 2 containing the conventional antioxidant K has lower oxidation stability in any oxidation stability test than that of the present invention, and particularly from the results of the oxidation stability test I. It can be seen that the lubricating oil composition of Comparative Example 2 cannot withstand use at high temperature for a long time. Further, the lubricating oil composition of Comparative Example 3 containing the antioxidant L has the same oxidative stability test I as that of Example, but the oxidative stability in the oxidative stability test II is the same as that of the present invention. Remarkably low in comparison.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C10M 129: 16) C10N 30:08 30:10 40:02 40:04 40:08 40:12 40 : 20 40:22 40:24 40:25 40:30 (72) Inventor Toshio Yoshida 8 Chidoricho, Naka-ku, Yokohama City Japan Petroleum Incorporated Central Research Laboratory

Claims (1)

[Claims] 1. [II] 2-tert represented by the following general formula (1) with respect to 100 parts by weight of a lubricating base oil.
A lubricating oil composition comprising 0.1 to 5 parts by weight of -butyl-4-alkyloxymethyl-6-alkylphenol. Embedded image [In the formula, R ¹ represents an alkyl group having 1 to 4 carbon atoms, and R ²
Represents an alkyl group or an alkenyl group having 1 to 24 carbon atoms. ]