JP2000169871A - Lubricating oil composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To have a long life of a machine in order to have good wear resistance and at the same time have excellent thermal stability and oxidation stability, and to prevent abrasion of a machine sliding part. Provided is a lubricating oil composition capable of extending the life of the lubricating oil itself. SOLUTION: At least one kind selected from mineral oil, fat and oil and synthetic oil is used as a base oil, and (A) a triaryl phosphate, (B) an alkylphenol and / or an aromatic amine, and (C) a fatty acid and / or ( D) The problem can be solved by using a lubricating oil composition containing an ester.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a lubricating oil composition, and more particularly to a lubricating oil composition having good wear resistance and excellent heat stability and oxidation stability.

[0002]

2. Description of the Related Art Conventionally, lubricating oils have been required to have good wear resistance from the viewpoint of extending the life of the machine used.
In recent years, in addition to this, the lubricating oil itself has been strongly demanded to have a longer service life for reasons such as labor saving of labor for machine maintenance and effective use of natural resources. In lubricating oils requiring abrasion resistance, antiwear agents such as zinc dithiophosphate and sulfur-phosphorus additives are usually used as additives. On the other hand, to extend the life of lubricating oil,
Although it is necessary to impart high thermal stability and oxidative stability, additives such as the above-mentioned zinc dithiophosphate and sulfur-phosphorus-based additives used for improving abrasion resistance have a heat load. When added, sludge is likely to be generated, which tends to reduce heat and oxidation stability. Therefore, it has been difficult for conventional lubricating oils using these additives to improve heat and oxidation stability while maintaining good wear resistance.

[0003]

DISCLOSURE OF THE INVENTION The present invention has good heat resistance and oxidation stability at the same time as having good abrasion resistance. It is an object of the present invention to provide a lubricating oil composition which can achieve lubrication and extend the life of the lubricating oil itself.

[0004]

Means for Solving the Problems As a result of repeated studies to overcome the above-mentioned problems, the present inventors have found that a lubricating base oil has a good abrasion resistance by containing a specific compound in combination. The present inventors have found that a lubricating oil composition having excellent heat and oxidation stability can be obtained, and have completed the present invention.

That is, the lubricating oil composition according to the present invention comprises:
A base oil comprising at least one selected from mineral oil, fats and oils, and (A) a triaryl phosphate;
It comprises an alkylphenol and / or an aromatic amine, and (C) a fatty acid.

Further, another lubricating oil composition according to the present invention comprises:
A base oil comprising at least one selected from mineral oil, fats and oils, and (A) a triaryl phosphate;
It comprises an alkylphenol and / or an aromatic amine and (D) an ester.

Further, another lubricating oil composition according to the present invention comprises:
A base oil comprising at least one selected from mineral oil, fats and oils, and (A) a triaryl phosphate;
It comprises an alkylphenol and / or aromatic amine, (C) a fatty acid, and (D) an ester.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The lubricating oil composition of the present invention is based on at least one selected from mineral oils, fats and oils, and synthetic oils. Examples of the mineral base oil usable in the present invention include solvent removal, solvent extraction, hydrocracking, and solvent removal for a lubricating oil fraction obtained by distilling crude oil under normal pressure and reduced pressure. And paraffinic or naphthenic mineral oils obtained by applying one or more kinds of refining means such as catalytic dewaxing, hydrorefining, sulfuric acid washing, and clay treatment in an appropriate combination.

The fats and oils include beef tallow, lard, soybean oil, rapeseed oil, rice bran oil, coconut oil, palm oil, palm kernel oil and hydrogenated products thereof. Examples of the synthetic oil include poly-α-olefins (ethylene-propylene copolymer, polybutene, isobutene oligomer, 1-octene oligomer, 1-decene oligomer, etc.) or hydrides thereof, isoparaffin, alkylbenzene, alkylnaphthalene, polyolefin, and the like. Examples thereof include oxyalkylene glycol, dialkyl diphenyl ether, polyphenyl ether, fluorinated polyolefin, and silicone oil.

As the base oil of the lubricating oil composition of the present invention, the above-described base oils may be used alone or in combination of two or more kinds in the form of a mixed base oil. The viscosity of the base oil used in the present invention is not particularly limited, but generally the kinematic viscosity at 40 ° C. is ² to 500 mm ² / s.
Are preferable, and those in the range of ² to 250 mm ² / s are more preferable. In addition, the viscosity index of the base oil used in the present invention is also arbitrary, but usually, a viscosity index of 85 or more is preferably used, and a viscosity index of 100 or more is more preferably used.

The component (A) in the lubricating oil composition of the present invention is a triaryl phosphate. As the triaryl phosphate, specifically, a compound represented by the following general formula (1) is preferably used.

[0012]

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In the general formula (1), R ¹ , R ² and R ³ are
A phenyl group, a naphthyl group or a carbon number 7
~ 18 alkylaryl groups are shown. As the alkylaryl group having 7 to 18 carbon atoms, specifically,
Tolyl group (the bonding position of the methyl group to the benzene ring is arbitrary), xylyl group (the bonding position of each methyl group to the benzene ring is arbitrary), ethylphenyl group (the bonding position of the ethyl group to the benzene ring) Is optional), a methylethylphenyl group (the bonding position of the methyl group and the ethyl group to the benzene ring is arbitrary), a diethylphenyl group (the bonding position of each ethyl group to the benzene ring is arbitrary), C9 to C1 such as propylphenyl, butylphenyl, pentylphenyl, hexylphenyl, heptylphenyl, octylphenyl, nonylphenyl, decylphenyl, undecylphenyl, dodecylphenyl, etc.
And a monoalkylphenyl group 8 (the alkyl group may be linear or branched, and the bonding position of the alkyl group to the benzene ring is arbitrary). From the point of excellent, phenyl group and carbon number 7
More preferred are alkylalkyl groups of 10 to 10. In the general formula (1), X ¹ , X ² , X ³ and X ⁴ each independently represent an oxygen atom or a sulfur atom, preferably an oxygen atom.

The triaryl phosphates more preferable as the component (A) of the present invention include, specifically, triphenyl phosphate, tricresyl phosphate, monocresyl diphenyl phosphate, dicresyl monophenyl phosphate, triphenyl thiophosphate, Examples thereof include tricresyl thiophosphate, monocresyl diphenyl thiophosphate, dicresyl monophenyl thiophosphate, and mixtures thereof. Of these, triphenyl phosphate, tricresyl phosphate, monocresyl diphenyl phosphate, dicresyl monophenyl phosphate are exemplified. Or a mixture thereof is particularly preferred.

The content of the component (A) in the lubricating oil composition of the present invention is optional, but the upper limit is preferably 10% by mass, more preferably 7% by mass, and still more preferably the total amount of the composition. Is 5% by weight, most preferably 2% by weight. If the content exceeds 10% by mass, no further improvement in abrasion resistance commensurate with the content is observed, and the storage stability may be impaired. On the other hand, the lower limit of the content of the component (A) is preferably 0.01% by mass, more preferably 0.02% by mass, still more preferably 0.05% by mass, and most preferably 0% by mass, based on the total amount of the composition. 0.1% by mass. When the content of the component (A) is less than 0.01% by mass, the effect of adding the component is not observed, and the wear resistance of the lubricating oil composition may be deteriorated.

The component (B) in the lubricating oil composition of the present invention comprises (B-1) an alkylphenol and / or (B-
2) It is an aromatic amine. As the alkylphenol (B-1), any alkylphenol-based compound used as an antioxidant in lubricating oils can be used, and is not particularly limited. For example, the following general formula (2) or One or more alkylphenol compounds selected from the compounds represented by the formula (3) are preferred.

[0017]

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In the above general formula (2), R ⁴ has 1 to 4 carbon atoms.
R ⁵ is a hydrogen atom or a carbon number of 1 to 4
R ⁶ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a group represented by the following general formula (i) or a group represented by the following general formula (ii) .

[0019]

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In the above general formula (i), R ⁷ has 1 to 6 carbon atoms.
And R ⁸ represents an alkyl group or alkenyl group having 1 to 24 carbon atoms.

[0021]

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In the above general formula (ii), R ⁹ has 1 to 1 carbon atoms.
6 represents an alkylene group, R ¹⁰ represents an alkyl group having 1 to 4 carbon atoms, and R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

[0023]

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In the above general formula (3), R ¹² and R ¹⁶ are
Each independently represents an alkyl group having 1 to 4 carbon atoms;
¹³ and R ¹⁷ are each independently a hydrogen atom or carbon atom 1
And R ¹⁴ and R ¹⁵ each independently represent an alkylene group having 1 to 6 carbon atoms, and Y is an alkylene group having 1 to 18 carbon atoms or represented by the following general formula (iii). Shows the group to be formed.

[0025]

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In the general formula (iii), R ¹⁸ and R
¹⁹ independently represents an alkylene group having 1 to 6 carbon atoms.

In the general formula (2), R ⁴ is specifically methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl. A tert-butyl group is preferred from the viewpoint of excellent oxidation stability.
As the R ^5, there may be mentioned an alkyl group having 1 to 4 carbon atoms, such as hydrogen atom or above, from the viewpoint of excellent oxidation stability, a methyl group or a tert- butyl group.

In the general formula (2), R ⁶ has 1 to 1 carbon atoms.
When it is an alkyl group of 4, specifically, R ⁶ is a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, or the like. However, from the viewpoint of excellent oxidation stability, a methyl group or an ethyl group is preferable.

Among the alkylphenols represented by the general formula (2), particularly preferred as a compound when R ⁶ is an alkyl group having 1 to 4 carbon atoms is 2,6-di-te
rt-butyl-p-cresol, 2,6-di-tert
-Butyl-4-ethylphenol and mixtures thereof.

When R ⁶ in the general formula (2) is a group represented by the general formula (i), the alkylene group having 1 to 6 carbon atoms represented by R ⁷ in the general formula (i) is It may be chain-like or branched, and specifically, for example, a methylene group, a methylmethylene group, an ethylene group (dimethylene group), an ethylmethylene group, a propylene group (methylethylene group), a trimethylene group, a linear or Examples include a branched butylene group, a linear or branched pentylene group, and a linear or branched hexylene group.

R ⁷ is an alkylene group having 1 to 2 carbon atoms, specifically, for example, a methylene group, a methylmethylene group, an ethylene group ( Dimethylene group) and the like.

On the other hand, the alkyl group or alkenyl group having 1 to 24 carbon atoms represented by R ⁸ in the general formula (i) may be linear or branched, and specifically, for example, methyl group, ethyl group Group, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodeci, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, Alkyl groups such as nonadecyl group, icosyl group, henycosyl group, docosyl group, tricosyl group, and tetracosyl group (these alkyl groups may be linear or branched); vinyl group, propenyl group, isopropenyl group, butenyl group , A pentenyl group, a hexenyl group,
Heptenyl group, octenyl group, nonenyl group, decenyl group, undecenyl group, dodecenyl group, tridecenyl group,
Alkenyl groups such as tetradecenyl group, pentadecenyl group, hexadecenyl group, heptadecenyl group, octadecenyl group, octadecadienyl group, nonadecenyl group, icosenyl group, henicocenyl group, docosenyl group, tricosenyl group and tetracosenyl group (these alkenyl groups are linear Or a branched bond, and the position of the double bond is also arbitrary). As R ⁸ , an alkyl group having 4 to 18 carbon atoms, specifically, for example, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, from the viewpoint of excellent solubility in a base oil. And alkyl groups such as undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, and octadecyl group (these alkyl groups may be linear or branched). ~ 12 linear or branched alkyl groups are more preferred, and the number of carbon atoms is 6 ~
Twelve branched alkyl groups are particularly preferred.

Among the phenol compounds represented by the general formula (2), when R ⁶ is a group represented by the general formula (i), R ⁷ in the general formula (i) is a compound having a carbon number of 1
A to 2 alkylene group, more preferably those wherein R ⁸ is linear or branched alkyl group having 6 to 12 carbon atoms,
It is particularly preferable that R ⁷ in the general formula (i) is an alkylene group having 1 to 2 carbon atoms, and R ⁸ is a branched alkyl group having 6 to 12 carbon atoms.

More specifically, preferred examples of the compound include n-hexyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) acetate and (3-methyl-5
-Tert-butyl-4-hydroxyphenyl) isohexyl acetate, (3-methyl-5-tert-butyl-4)
-Hydroxyphenyl) acetic acid n-heptyl, (3-methyl-5-tert-butyl-4-hydroxyphenyl)
Isoheptyl acetate, n-octyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) acetate, (3
-Methyl-5-tert-butyl-4-hydroxyphenyl) acetate isooctyl, (3-methyl-5-tert)
-Butyl-4-hydroxyphenyl) acetic acid 2-ethylhexyl, (3-methyl-5-tert-butyl-4-hydroxyphenyl) acetic acid n-nonyl, (3-methyl-5
-Tert-butyl-4-hydroxyphenyl) isononyl acetate, (3-methyl-5-tert-butyl-4-)
N-decyl (hydroxyphenyl) acetate, (3-methyl-
5-tert-butyl-4-hydroxyphenyl) isodecyl acetate, (3-methyl-5-tert-butyl-4)
-Hydroxyphenyl) n-undecyl acetate, (3-methyl-5-tert-butyl-4-hydroxyphenyl) isoundecyl acetate, (3-methyl-5-tert)
-Butyl-4-hydroxyphenyl) acetate n-dodecyl, (3-methyl-5-tert-butyl-4-hydroxyphenyl) isododecyl acetate, (3-methyl-5-
n-hexyl tert-butyl-4-hydroxyphenyl) propionate, isohexyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate, (3-methyl-5-tert-butyl-4-hydroxyphenyl) ) N-Heptyl propionate, (3-methyl-5-tert-butyl-4-hydroxyphenyl)
Isoheptyl propionate, (3-methyl-5-ter
t-butyl-4-hydroxyphenyl) propionic acid n
-Octyl, (3-methyl-5-tert-butyl-4
-Hydroxyphenyl) isooctyl propionate,
2-ethylhexyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate, n-nonyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate, (3-methyl-5 −te
rt-butyl-4-hydroxyphenyl) isononyl propionate, (3-methyl-5-tert-butyl-4)
-Hydroxyphenyl) n-decyl propionate, (3
-Methyl-5-tert-butyl-4-hydroxyphenyl) isodecyl propionate, (3-methyl-5-t
n-undecyl tert-butyl-4-hydroxyphenyl) propionate, isoundecyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate, (3-methyl-5-tert-butyl-4-hydroxyphenyl) ) N-dodecyl propionate, isododecyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate, (3,5-di-ter
n-hexyl (t-butyl-4-hydroxyphenyl) acetate, isohexyl (3,5-di-tert-butyl-4-hydroxyphenyl) acetate, (3,5-di-tert)
N-heptyl-butyl-4-hydroxyphenyl) acetate, isoheptyl (3,5-di-tert-butyl-4-hydroxyphenyl) acetate, (3,5-di-tert)
N-octyl-butyl-4-hydroxyphenyl) acetate, isooctyl (3,5-di-tert-butyl-4-hydroxyphenyl) acetate, (3,5-di-tert)
-Butyl-4-hydroxyphenyl) acetic acid 2-ethylhexyl, (3,5-di-tert-butyl-4-hydroxyphenyl) acetic acid n-nonyl, (3,5-di-ter
isononyl (t-butyl-4-hydroxyphenyl) acetate, n-decyl (3,5-di-tert-butyl-4-hydroxyphenyl) acetate, (3,5-di-tert-acetate)
Butyl-4-hydroxyphenyl) isodecyl acetate,
N-undecyl (3,5-di-tert-butyl-4-hydroxyphenyl) acetate, (3,5-di-tert-butyl)
Isoundecyl butyl-4-hydroxyphenyl) acetate, n-dodecyl (3,5-di-tert-butyl-4-hydroxyphenyl) acetate, (3,5-di-tert)
-Butyl-4-hydroxyphenyl) isododecyl acetate, n-hexyl (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, (3,5-di-
tert-butyl-4-hydroxyphenyl) isohexyl propionate, (3,5-di-tert-butyl-
4-hydroxyphenyl) n-heptyl propionate,
(3,5-di-tert-butyl-4-hydroxyphenyl) isoheptyl propionate, (3,5-di-te
n-octyl rt-butyl-4-hydroxyphenyl) propionate, (3,5-di-tert-butyl-4-)
(Hydroxyphenyl) isooctyl propionate,
2-ethylhexyl (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, n-nonyl (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, (3,5-diphenyl) -Tert-butyl-
4-hydroxyphenyl) isononyl propionate,
N-decyl (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, (3,5-di-ter-
isodecyl (tert-butyl-4-hydroxyphenyl) propionate, n-undecyl (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, (3,
5-di-tert-butyl-4-hydroxyphenyl)
Isoundecyl propionate, (3,5-di-tert
-Butyl-4-hydroxyphenyl) propionic acid n-
Dodecyl, isododecyl (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, and mixtures thereof.

When R ⁶ in the general formula (2) is a group represented by the general formula (ii), R ⁶ in the general formula (ii)
⁹ represents an alkylene group having 1 to 6 carbon atoms. The alkylene group may be linear or branched,
Specific examples include the various alkylene groups exemplified above for R ⁷ . R ⁹ is an alkylene group having 1 to 3 carbon atoms, for example, methylene group, methylmethylene group, ethylene Groups (dimethylene group), ethylmethylene group, propylene group (methylethylene group), trimethylene group and the like are more preferable.

R ¹⁰ in the general formula (ii) is
Specifically, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-
Examples thereof include a butyl group and a tert-butyl group, and a tert-butyl group is preferable from the viewpoint of excellent oxidation stability. Examples of R ¹¹ include a hydrogen atom and an alkyl group having 1 to 4 carbon atoms as described above, and a methyl group or a tert-butyl group is preferable from the viewpoint of excellent oxidation stability.

Among the alkylphenols represented by the general formula (2), when R ⁶ is a group represented by the general formula (ii), preferred compounds are specifically exemplified by bis (3,3) 5-di-tert-butyl-4-hydroxyphenyl) methane, 1,1-bis (3,5-di-t)
tert-butyl-4-hydroxyphenyl) ethane,
1,2-bis (3,5-di-tert-butyl-4-hydroxyphenyl) ethane, 1,1-bis (3,5-di-tert-butyl-4-hydroxyphenyl) propane, 1,2- Bis (3,5-di-tert-butyl-4
-Hydroxyphenyl) propane, 1,3-bis (3,
5-di-tert-butyl-4-hydroxyphenyl)
Examples include propane, 2,2-bis (3,5-di-tert-butyl-4-hydroxyphenyl) propane, and mixtures thereof.

On the other hand, in the above general formula (3), R ¹²
And R ¹⁶ are each independently an alkyl group having 1 to 4 carbon atoms, specifically, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group,
An ec-butyl group, a tert-butyl group and the like are shown, and both are preferably a tert-butyl group from the viewpoint of excellent oxidation stability. R ¹³ and R ¹⁷ each independently include a hydrogen atom or an alkyl group having 1 to 4 carbon atoms as described above. However, from the viewpoint of excellent oxidation stability, each independently represents a methyl group or tert. Preferably it is a -butyl group.

In the general formula (3), R ¹⁴ and R
The alkylene group having 1 to 6 carbon atoms which represents ¹⁵ may be linear or branched, and specifically includes the various alkylene groups described above for R ⁷ individually. The point that the compound represented by the general formula (3) can be produced in a small number of reaction steps and that the raw materials thereof are easily available
R ¹⁴ and R ¹⁵ are each more preferably an alkylene group having 1 to 2 carbon atoms, specifically, for example, a methylene group, a methylmethylene group, an ethylene group (dimethylene group) and the like.

In the general formula (3), examples of the alkylene group having 1 to 18 carbon atoms representing Y include, for example, a methylene group, a methylmethylene group, an ethylene group (dimethylene group), an ethylmethylene group, Propylene group (methylethylene group), trimethylene group, butylene group, pentylene group, hexylene group, heptylene group, octylene group, nonylene group, decylene group, undecylene group, dodecylene group, tridecylene group, tetradecylene group, pentadecylene group, hexadecylene group, Heptadecylene group, octadecylene group and the like (these alkylene groups may be linear or branched).
An alkylene group having 1 to 6 carbon atoms, specifically, for example, a methylene group, a methylmethylene group, an ethylene group (dimethylene group), an ethylmethylene group, a propylene group (methylethylene group), a trimethylene group, a butylene group, a pentylene group,
Hexylene groups and the like (these alkylene groups may be linear or branched) are more preferable, and ethylene groups (dimethylene groups), trimethylene groups, linear butylene groups (tetramethylene groups, linear pentylene groups (pentamethylene groups) ), A straight-chain alkylene group having 2 to 6 carbon atoms such as a straight-chain hexylene group (hexamethylene group), etc. In the alkylphenol represented by the general formula (3), Y represents an alkylene having 1 to 18 carbon atoms. Particularly preferred as the compound when it is a group is a compound represented by the following formula (4).

[0041]

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In the general formula (3), Y is the general formula (ii)
In the case where it is a group represented by i),
The alkylene groups having 1 to 6 carbon atoms represented by R ¹⁸ and R ¹⁹ in i) may be linear or branched. Specifically, each of them is individually described above for R ⁷ . Such various alkylene groups are mentioned. Since raw materials for producing the compound of the general formula (3) are easily available, R ¹⁸ and R ¹⁹ are each independently an alkylene group having 1 to 3 carbon atoms, specifically, for example, a methylene group, methyl Methylene group, ethylene group (dimethylene group), ethylmethylene group,
More preferably, it is a propylene group (methylethylene group), a trimethylene group or the like.

Among the alkylphenols represented by the general formula (3), those particularly preferred as compounds when Y is a group represented by the general formula (iii) are represented by the following formula (5)
It is a compound shown by these.

[0044]

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On the other hand, as the aromatic amine (B-2),
Any aromatic amine compound used as an antioxidant for a lubricating oil can be used, and is not particularly limited. For example, a compound represented by the following general formula (6) (N-
One or more aromatic amines selected from p-alkyl) phenyl-α-naphthylamine and p, p′-dialkyldiphenylamine represented by the general formula (7) are preferred.

[0046]

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In the above formula (6), R ²⁰ represents a hydrogen atom or an alkyl group having 1 to 16 carbon atoms.

[0048]

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In the general formula (7), R ²¹ and R ²² each independently represent an alkyl group having 1 to 16 carbon atoms.

In the above formula (6) representing (Np-alkyl) phenyl-α-naphthylamine, R ²⁰ represents a hydrogen atom or a linear or branched alkyl group having 1 to 16 carbon atoms. I have. When the number of carbon atoms in R ²⁰ exceeds 16, the proportion of the functional group in the molecule becomes small, and the antioxidant ability may be weakened.

Examples of the alkyl group represented by R ²⁰ include, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, Dodeci, tridecyl, tetradecyl, pentadecyl, hexadecyl, etc. (these alkyls may be linear or branched)
Is mentioned.

Among the compounds represented by the general formula (6), R
^{When 20} is an alkyl group, a branched alkyl group having 8 to 16 carbon atoms is preferable from the viewpoint of excellent solubility of its own oxidation product in the base oil, and further, an oligomer of an olefin having 3 or 4 carbon atoms is preferable. A derived C8-16 branched alkyl group is more preferred. Specific examples of the olefin having 3 or 4 carbon atoms include propylene, 1
-Butene, 2-butene and isobutylene, but propylene or isobutylene is preferred because of its excellent solubility of the oxidation product of itself in the base oil.

When (Np-alkyl) phenyl-α-naphthylamine represented by the above formula (6) is used as the component (B-2) in the present invention, R ²⁰ is a hydrogen molecule or isobutylene dimer. Branched octyl group derived from a dimer, branched nonyl group derived from a trimer of propylene, branched dodecyl group derived from a trimer of isobutylene, branched dodecyl derived from a tetramer of propylene Particularly preferred is a branched pentadecyl group derived from a pentamer or a pentamer of propylene, a branched octyl group derived from a hydrogen molecule or a dimer of isobutylene, a branched dodecyl group derived from a trimer of isobutylene or Branched dodecyl groups derived from propylene tetramers are particularly preferred.

When Np-alkylphenyl-α-naphthylamine in which R ²⁰ is an alkyl group is used as the aromatic amine represented by the general formula (6), the Np-alkylphenyl-α-naphthylamine is May be commercially available. Phenyl-α-naphthylamine and a halogenated alkyl compound having 1 to 16 carbon atoms;
It can be easily synthesized by reacting an olefin having from 16 to 16 or an olefin oligomer having from 2 to 16 carbon atoms with phenyl-α-naphthylamine using a Friedel-Crafts catalyst. As the Friedel-Crafts catalyst at this time, specifically, for example, metal halides such as aluminum chloride, zinc chloride and iron chloride; sulfuric acid,
Acid catalysts such as phosphoric acid, phosphorus pentoxide, boron fluoride, acid clay, activated clay and the like can be used.

On the other hand, in the above general formula (7) representing p, p'-dialkyldiphenylamine, R ²¹ and R ²² each independently represent an alkyl group having 1 to 16 carbon atoms. When one or both of R ²¹ and R ²² is a hydrogen atom, it may itself precipitate as sludge by oxidation. On the other hand, when the number of carbon atoms exceeds 16, the proportion of the functional group in the molecule is small. And the antioxidant ability may be weakened.

As R ²¹ and R ²² , specifically, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, Dodeci, tridecyl, tetradecyl, pentadecyl, hexadecyl, etc. (these alkyls may be linear or branched)
Is mentioned. Among these, as R ²¹ and R ²² ,
A branched alkyl group having 3 to 16 carbon atoms is preferred from the viewpoint of excellent solubility of its own oxidation product in a base oil, and further, a 3 to 4 carbon atom-derived olefin or a 3 to 4 carbon atom derived from an oligomer thereof is preferred. Sixteen branched alkyl groups are more preferred. Specific examples of the olefin having 3 or 4 carbon atoms include propylene, 1-butene, 2-butene, isobutylene, and the like, and are excellent in solubility of an oxidation product of itself in a lubricating base oil. From the viewpoint, propylene or isobutylene is preferred.

When p, p'-dialkyldiphenylamine represented by the above general formula (7) is used as the component (B-2) in the present invention, R ²¹ and R ²² are each an isopropyl group derived from propylene or isobutylene. A tert-butyl group derived from a propylene dimer, a branched hexyl group derived from a propylene dimer, a branched octyl group derived from an isobutylene dimer, and a branched nonyl group derived from a propylene trimer. , A branched dodecyl group derived from a trimer of isobutylene, a branched dodecyl group derived from a tetramer of propylene or a branched pentadecyl group derived from a pentamer of propylene is particularly preferred. A tert-butyl group, a branched hexyl group derived from a propylene dimer, and a branched hexyl group derived from an isobutylene dimer. Particularly preferred are a branched octyl group, a branched nonyl group derived from a propylene trimer, a branched dodecyl group derived from an isobutylene trimer, or a branched dodecyl group derived from a propylene tetramer.

As the p, p'-dialkyldiphenylamine represented by the general formula (7), a commercially available product may be used. Further, similarly to the Np-alkylphenyl-α-naphthylamine represented by the general formula (6), diphenylamine and a halogenated alkyl compound having 1 to 16 carbon atoms, an olefin having 2 to 16 carbon atoms, or 2 to 2 carbon atoms are used. It can be easily synthesized by reacting 16 olefins or their oligomers with diphenylamine using a Friedel-Crafts catalyst. As the Friedel-Crafts catalyst at this time, specifically, for example, metal halides and acidic catalysts listed in the synthesis of Np-alkylphenyl-α-naphthylamine are used.

As a matter of course, as the component (B) of the present invention, alkylphenols represented by the general formulas (2) and (3), and the general formulas (6) and (7) 1 selected from aromatic amines represented by
These compounds may be used alone, or a mixture of two or more compounds selected from the above at an arbitrary mixing ratio may be used.

The content of the component (B) in the lubricating oil composition of the present invention is optional, but its upper limit is preferably 10% by mass, more preferably 7% by mass, and still more preferably, based on the total amount of the composition. Is 5% by weight, most preferably 2% by weight. If the content exceeds 10% by mass, no further improvement in abrasion resistance commensurate with the content is observed, and the storage stability may be impaired.

On the other hand, the lower limit of the content of the component (B) is preferably 0.01% by mass, more preferably 0.02% by mass, still more preferably 0.05% by mass, based on the total amount of the composition. Preferably, it is 0.1% by mass. When the content of the component (B) is less than 0.01% by mass, the effect of the addition is not observed, and the wear resistance of the lubricating oil composition may be deteriorated. The lubricating oil composition of the present invention contains, as an essential component, a fatty acid as the component (C) or an ester as the component (D) in addition to the components (A) and (B).

The fatty acid of component (C) in the lubricating oil composition of the present invention may be an aliphatic monobasic acid having one carboxyl group in one molecule, or having two carboxyl groups in one branch. It may be an aliphatic dibasic acid. As the aliphatic monobasic acid, one having 6 to 24 carbon atoms is usually used. The aliphatic group may be linear or branched, and may be a saturated fatty acid or an unsaturated fatty acid.

As the aliphatic monobasic acid having 6 to 24 carbon atoms, specifically, heptanoic acid, octanoic acid, nonanoic acid,
Decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid,
Tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, icosanoic acid, henicosanoic acid, docosanoic acid, tricosanoic acid, tetracosanoic acid, pentacosanoic acid, hexacosanoic acid, heptacosanoic acid, octacosanoic acid, nonacosanoic acid, triacontyl group (Saturated aliphatic groups may be linear or branched); heptenoic acid, octenoic acid, nonenoic acid, decenoic acid, undecenoic acid, dodecenoic acid, tridecenoic acid, tetradecenoic acid, pentadecenic acid Acid, hexadecenoic acid, heptadecenoic acid, octadecenoic acid, nonadecenoic acid, icosenoic acid, heniccosenic acid, docosenoic acid, tricosenoic acid, tetracosenoic acid, pentacosenoic acid, hexacosenoic acid, heptacosenoic acid, octacosenic acid, nonacosenic acid, triaconthenic acid Unsaturated aliphatic monobasic acid (unsaturated aliphatic group may be branched be linear, also the position of the double bond is also arbitrary) or mixtures thereof and the like can be exemplified.

As the aliphatic dibasic acid, those having 2 to 10 carbon atoms are usually preferably used. As these aliphatic dibasic acids, specifically, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid,
Subaruic acid, azelaic acid, sebacic acid, methylmalonic acid, ethylmalonic acid, dimethylmalonic acid, methylsuccinic acid, 2,2-dimethylsuccinic acid, 2,3-dimethylsuccinic acid, 2-ethyl-2-methylsuccinic acid, 2 -Methylglutaric acid, 3-methylglutaric acid, unsaturated aliphatic dibasic acids such as maleic acid, fumaric acid, itaconic acid, citraconic acid, and mesaconic acid; These mixtures can be exemplified.

As the component (C) in the lubricating oil composition of the present invention, a linear chain derived from lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, and various fats and oils is particularly preferred because of its excellent abrasion resistance. Linear aliphatic monobasic acids having 12 to 18 carbon atoms of fatty acids (coconut oil fatty acids and the like) are particularly preferably used.

The content of the component (C) in the lubricating oil composition of the present invention is arbitrary, but its upper limit is preferably 5% by mass, more preferably 3% by mass, based on the total amount of the composition.
More preferably, it is 2% by mass, most preferably 1% by mass. If the content exceeds 5% by mass, no further improvement in abrasion resistance commensurate with the content is observed, and the storage stability may be impaired.

On the other hand, the lower limit of the content of the component (C) is preferably 0.001% by mass, more preferably 0.005% by mass, and still more preferably 0.01% by mass, based on the total amount of the composition.
%, Most preferably 0.05% by weight. (C)
When the content of the component is less than 0.001% by mass, the effect of adding the component is not observed, and the wear resistance of the lubricating oil composition may be deteriorated.

The component (D) in the lubricating oil composition of the present invention is an ester, and specific examples include an ester comprising an alcohol and / or phenol and a fatty acid. The alcohol constituting the ester may be a monohydric alcohol or a polyhydric alcohol.
As the monohydric alcohol, an aliphatic alcohol having 1 to 24 carbon atoms is usually used. As the aliphatic alcohol having 1 to 24 carbon atoms, specifically, methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol Examples thereof include nol, hexadecanol, heptadecanol, octadecanol, nonadecanol, icosenol, henicocenol, docosenol, tricosenol, and tetracosenol.

As the polyhydric alcohol, 2 to 10
Polyhydric alcohols are preferably used. Specific examples of these polyhydric alcohols include ethylene glycol, diethylene glycol, polyethylene glycol (3 to 15 mer of ethylene glycol), propylene glycol, dipropylene glycol, and polypropylene glycol (propylene glycol). 3-15 mer), 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,2-
Dihydric alcohols such as propanediol, 2-methyl-1,3-propanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, and neopentyl glycol Glycerin, polyglycerin (2 to 8 of glycerin);
Dimers, such as diglycerin, triglycerin, tetraglycerin, etc.), trimethylolalkanes (trimethylolethane, trimethylolpropane, trimethylolbutane, etc.) and dimers and octamers thereof, pentaerythritol and dimers of these tetramers. Body, 1,2,4-butanetriol, 1,3,5-pentanetriol, 1,2,6
Polyhydric alcohols such as hexanetriol, 1,2,3,4-butanetetrol, sorbitol, sorbitan, sorbitol glycerin condensate, adonitol, arabitol, xylitol, mannitol; xylose, arabinose, ribose, rhamnose, glucose, fructose, Examples include sugars such as galactose, mannose, sorbose, cellobiose, maltose, isomaltose, trehalose, and sucrose.

The alcohol constituting the ester of the component (D) may be the above-mentioned aliphatic alcohol or a phenol compound. As the phenol compound here, one having 6 to 12 carbon atoms is usually used, and specifically, phenol, methylphenol (also known as cresol), ethylphenol, dimethylphenol, propylphenol, ethylmethylphenol, trimethylphenol And alkylphenols such as butylphenol, pentylphenol, and hexylphenol (the alkyl group may be linear or branched, and the bonding position to the benzene ring is arbitrary).

As the fatty acid constituting the ester of the component (D), specifically, the same fatty acids as those exemplified as the fatty acid of the component (C) can be used. In addition,
In the case where a polyhydric alcohol is used as the alcohol constituting the ester of the component (D), a complete ester in which all of the hydroxyl groups are esterified may be used, and the form of the hydroxyl group in which at least one of the hydroxyl groups is not esterified may be used. May be the remaining partial ester, but is preferably a complete ester. In this case, only one type of fatty acid may be used, or two or more types of fatty acids may be used. Similarly, when a dibasic acid is used as the fatty acid constituting the ester of the component (D), it may be a complete ester in which all of the carboxyl groups are esterified, and at least one of the carboxyl groups may be esterified. It may be a partial ester remaining in the form of a carboxyl group that is not formed, but is preferably a complete ester. In this case, only one kind of alcohol may be used, or two kinds of alcohols may be used.

Particularly preferred as the ester of the component (D) are, specifically, methyl laurate, ethyl laurate, propyl laurate, butyl laurate, and the like.
Methylisolaurate, ethylisolaurate, propylisolaurate, butylisolaurate, methylmyristate, ethylmyristate, propylmyristate, butylmyristate, methylisomyristate, ethylisomyristate, propylisomyristate , Butyl isomyristate, methyl palmitate, ethyl palmitate, propyl palmitate, butyl palmitate, methyl isopalmitate, ethyl isopalmitate, propyl isopalmitate, butyl isopalmitate, methyl stearate, ethyl stearate, Propyl stearate, butyl stearate, methyl isostearate, ethyl isostearate, propyl isostearate, butyl isostearate, methyl oleate, ethyl oleate, Monoesters such as propyl oleate, butyl oleate, methyl isooleate, ethyl isooleate, propyl isooleate, butyl isooleate, glycerin trilaurate, glycerin trinoisolaurate, glycerin trimyristate, glycerin triisolate Myristate, glycerin tripalmitate, glycerin triisopalmitate, glycerin tristearate, glycerin triisostearate, glycerin trioleate, glycerin triisooleate, trimethylol ethane trilaurate, trimethylol ethane triisolaurate, tri Methylol ethane trimyristate, trimethylol ethane triisomyristate, trimethylol ethane tripalmitate, trimethylol ethane triisopallate Tate, trimethylolethanetristearate, trimethylolethanetriisostearate, trimethylolethanetrioleate, trimethylolethanetriisooleate, trimethylolpropanetrilaurate, trimethylolpropanetriisolaurate, trimethylolpropanetrimilli State, trimethylolpropane triisomyristate, trimethylolpropane tripalmitate, trimethylolpropane triisopalmitate, trimethylolpropane tristearate, trimethylolpropane triisostearate, trimethylolpropane trioleate, trimethylolpropane trilate Isooleate, pentaerythritol tetralaurate, pentaerythritol tetraisolaurate, pentaerythritol Thritol tetramyristate, pentaerythritol tetraisomyristate, pentaerythritol tetrapalmitate, pentaerythritol tetraisopalmitate, pentaerythritol tetrastearate, pentaerythritol tetraisostearate,
Pentaerythritol tetraoleate, pentaerythritol tetraisooleate, sorbitan pentalaurate, sorbitan pentaisolaurate, sorbitan pentamyristate, sorbitan pentaisomyristate, sorbitan pentapalmitate, sorbitan pentaisopalmitate, sorbitan pentastearate Sorbitan pentaisostearate, sorbitan pentaoleate, sorbitan pentaisooleate, and mixtures thereof.

The content of the component (D) in the lubricating oil composition of the present invention is optional, but the upper limit is preferably 40% by mass, more preferably 20% by mass, and still more preferably the total amount of the composition. Is 10% by weight, most preferably 5% by weight. Even if the content exceeds 40% by mass, no further improvement effect of the abrasion resistance corresponding to the content is observed.
In addition, storage stability may be deteriorated.

On the other hand, the lower limit of the content of the component (D) is preferably 0.01% by mass, more preferably 0.05% by mass, still more preferably 0.1% by mass, based on the total amount of the composition. Preferably it is 0.5% by mass. When the content of the component (D) is less than 0.01% by mass, the effect of adding the component is not observed, and the wear resistance of the lubricating oil composition may be deteriorated. Further, in the lubricating oil composition of the present invention,
It is also possible to use the ester of the component (D) as the whole base oil or a part of the base oil. In this case, the upper limit of the content of the ester corresponding to the component (D) is based on the total amount of the lubricating oil composition. , Preferably 99.9% by weight, more preferably 90% by weight.
%, More preferably 50% by mass.

As described above, the lubricating oil composition of the present invention contains the components (A), (B) and (C) in the base oil, or the components (A), (B) and (B) in the base oil. The component D) is contained as an essential component, and the base oil contains the four components (A), (B), (C) and (D) as essential components. Thereby, a lubricating oil composition having further improved abrasion resistance and thermal / oxidative stability can be obtained. In this case, the content of the component (C) and the content of the component (D) are also optional. However, the preferred content in the case of including the component (C) alone and the case of including the component (D) alone is more preferable. A preferable content, a more preferable content, and a range as described above as a particularly preferable content are preferably used.

The lubricating oil composition of the present invention may be used in a form in which other various additives are blended, if necessary, in order to enhance its excellent properties. Examples of such additives include metal deactivators such as benzotriazole and alkyl thiadiazole; antifoaming agents such as silicone oil and fluorosilicone oil; demulsifiers such as condensation products of ethylene oxide and propylene oxide; polymethacrylate and the like. Pour point depressants; viscosity index improvers such as polymethacrylates, polybutenes, polyalkylstyrenes, olefin copolymers, styrene-diene copolymers, and styrene-maleic anhydride copolymers.

When these additives are added to the lubricating oil composition of the present invention, they may be used alone or in combination of two or more. The amount of addition of these known additives is optional, but usually,
It is preferable to add an amount such that the total amount of these known additives is 15% by mass or less based on the total amount of the composition.

The lubricating oil composition of the present invention has abrasion resistance and heat and heat resistance.
Lubricating oils that require oxidation stability, specifically those that are preferably used as hydraulic oils, etc., are also used as lubricating oils such as industrial gear oils, bearing oils, compressor oils, etc. It is preferably used.

[0079]

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

(Examples 1 to 11 and Comparative Examples 1 to 15) Lubricating oil compositions according to the present invention were prepared according to the compositions shown in Table 1 (Examples 1 to 11). Further, compositions for comparison were prepared with the compositions shown in Table 2 (Comparative Examples 1 to 15). The components used in Examples 1 to 11 and Comparative Examples 1 to 15 are as follows. (Base oil) Base 1: Highly paraffinic solvent refined mineral oil (32.0 mm ²
/ S (＠ 40 ° C.)) Group 2: Poly-α-olefin hydride (number average molecular weight 6
00) and dioctyl adipate in a 85:15 (volume ratio) mixed oil (32.0 mm ² / s (@ 40 ° C.)) (A) component A1: tricresyl phosphate A2: monocresyl diphenyl phosphate (B) component B1: 2,6-di-tert-butyl-paracresol B2: P, P′-di-branched octyldiphenylamine (C) component C1: oleic acid C2: stearic acid (D) component D1: butyl stearate D2: Glycerin trioleate Other E1: Zinc dialkyl dithiophosphate E2: Di-2-ethyl-hexyl acid thiophosphate

Examples 1 to 11 and Comparative Examples 1 to 15
The composition was evaluated for abrasion resistance and thermal / oxidative stability by the following test methods. Table 1 shows the results of Examples 1 to 11, and Table 2 shows the results of Comparative Examples 1 to 15.

[Evaluation Test Method] (Abrasion resistance): Vane pump test “Standard Test Meth” specified in ASTM D2882
od for Indicating the Wear Characteristics of Petr
oleum and Non-Petroleum Hydraulic Liquidsin a Cons
In accordance with “tant Volume Vane Pump”, the wear time of the vane and ring of the vane pump was measured after a test time of 500 hours. (Heat and oxidation stability): Thermal stability test “Lubricating oil” specified in JIS K 2540 Put the sample oil in a 50 ml beaker according to the
5 g was sampled, copper and iron catalysts were put therein, left in a thermostat at 140 ° C. for 20 days, and the amount of sludge in the sample oil was measured. The copper and iron catalysts used were those obtained by cutting a catalyst used in a turbine oil oxidation stability test (JIS K 2514) into eight turns (about 3.5 cm in length).

[0083]

[Table 1]

[0084]

[Table 2]

The lubricating oil compositions of the present invention shown in Table 1 (Examples 1 to 11) had less wear and sludge than the compositions of Comparative Examples 1 to 15 shown in Table 2. It can be seen that it has both excellent performances such as excellent abrasion resistance and thermal / oxidative stability.

[0086]

Industrial Applicability The lubricating oil composition of the present invention has good abrasion resistance as well as excellent thermal stability and oxidation stability. The service life can be extended, and the service life of the lubricating oil itself can be extended.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) C10M 129: 40 129: 70 129: 74) C10N 30:06 30:08 30:10 F term (reference) 4H104 BB05C BB16C BB17C BB18C BB32C BB34C BE07C BG14C BH03C BH06C DA02A DA06A EB02 LA03 LA04 LA05 PA01 PA02 PA05

Claims (3)

[Claims] 1. A base oil comprising at least one selected from mineral oils, fats and oils, and synthetic oils, comprising (A) a triaryl phosphate, (B) an alkylphenol and / or an aromatic amine, and (C) a fatty acid. A lubricating oil composition comprising: 2. A base oil comprising at least one selected from mineral oils, fats and oils, and synthetic oils, comprising (A) a triaryl phosphate, (B) an alkylphenol and / or an aromatic amine, and (D) an ester. A lubricating oil composition comprising: 3. A base oil comprising at least one selected from mineral oils, fats and oils and synthetic oils, wherein (A) a triaryl phosphate, (B) an alkylphenol and / or an aromatic amine, (C) a fatty acid, and (D) A) a lubricating oil composition comprising an ester.