JPH07216378A - Lubricating oil composition - Google Patents

Abstract

PURPOSE:To obtain a lubricating oil compsn. having greatly improved friction and wearing characteristics and suitable as an engine oil by adding a specific metal dithiocarbamate the extreme-pressure additive and further adding a specific organozinc compd. to a lubricating oil. CONSTITUTION:This lubricating oil compsn. is prepd. by compounding a lubricating oil with 0.01-10wt.% (based on the compsn.) metal dithiocarbamate of formula I (wherein M is Mo or W; at least one of R<1> to R<4> is a 5-20C alkyl with a secondary carbon atom bonded to N and the rest are each H, a 1-20C alkyl a 6-20C aryl, etc.; and one of X1 and X2 or of Y1 and Y2 is O and the other is S). Further, 0.01-7wt.% organozing compd. [e.g. zinc dithiophosphate of formula II (wherein R<5> to R<8> each is H, a 1-20C alkyl, a 6-26C aryl, etc.) or zinc dithiocarbamate] is added to the compsn. Thus obtd. compsn. has friction and wearing characteristics far better than those of a lubricating oil contg. a conventional magnetized metal dithiocarbamate, is suitable for the boundary lubrication of an internal combustion engine, and contains a very low amt. of or no phosphorus.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a lubricating oil composition,
More specifically, it relates to a lubricating oil composition having good wear resistance, extreme pressure resistance, and a low friction coefficient. The lubricating oil composition of the present invention can achieve extremely low phosphorus content or no phosphorus content, and can be used in a wide variety of fields such as lubricating oil for internal combustion engines.

[0002]

2. Description of the Related Art Lubricating oil for internal combustion engine (engine oil) is mainly used for piston rings and cylinder liners, bearings for crankshafts and connecting rods (connecting rods), valve mechanisms including cams and valve lifters, oil pumps and distributors. In addition to lubrication of various sliding parts such as drive devices, it also functions to cool the engine, clean and disperse combustion products, and prevent rust and corrosion. In this way, engine oil is required to have a variety of performances, and in addition, high performance, high output of the engine,
The required performance is changing with the harsh operating conditions.
For this reason, various additives such as antiwear agents, metal detergents, ashless dispersants, and antioxidants are blended with engine oils for the purpose of satisfying various performances.

As a basic function of engine oil, it is important that the engine operates smoothly under all conditions to prevent wear and seizure. The engine lubrication part is normally in a fluid lubrication state, but it is likely to be in a boundary lubrication state at a valve train, a top dead center of a piston, and the like. Antiwear properties under boundary lubrication of engine oils are generally imparted by the addition of zinc dialkyldithiophosphate (ZnDTP). However, ZnDTP has a problem that the exhaust gas control system is deteriorated because phosphorus (P) contained in the ZnDTP poisons the catalyst and the oxygen sensor. In addition, Zn
DTP easily loses its wear resistance due to the interaction with other additives such as succinimide and alkylamine.
Therefore, an extremely low phosphorus-free or phosphorus-free lubricating oil composition is desired.

On the other hand, in a gasoline engine, since a large amount of energy is lost in a friction portion where lubricating oil is involved, a friction modifier (friction modifier) is added as a measure for reducing friction loss and fuel consumption. As the friction reducing agent, an extreme pressure agent such as molybdenum sulfide dialkyldithiocarbamate or a compound belonging to an oily agent such as octadecylamine is used. Among these, molybdenum sulfide dialkyldithiocarbamate, which is a dithiocarbamate type organic molybdenum compound, has a particularly large friction reducing effect. However, molybdenum dialkyldithiocarbamate sulfides, which have been conventionally used, are still insufficient in wear resistance and frictional characteristics, and in the current situation where fuel economy performance is required more and more for engine oils, further improvement in performance is required. There is.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a lubricating oil composition having excellent wear resistance and frictional properties. More specifically, the object of the present invention is an extreme pressure agent comprising a dithiocarbamate type organometallic compound,
It is an object of the present invention to provide a lubricating oil composition containing an organometallic compound having significantly improved friction characteristics and wear resistance as compared with conventional products. Another object of the present invention is to provide a lubricating oil composition having further improved wear resistance and friction characteristics by using a dithiophosphate type organometallic compound in combination.

The present inventor has found that a conventional dithiocarbamate type organometallic compound such as molybdenum dialkyldithiocarbamate has a structure in which an alkyl group is bonded to a nitrogen atom through its primary carbon atom (that is, --CH _2-). N
We paid attention to having <). As a result of various studies on the alkyl group, a structure in which the secondary carbon atom of the alkyl group is bonded to the nitrogen atom (ie,> CH
A dithiocarbamate type organometallic compound having -N <), in which a metal salt of dithiocarbamic acid having a metal atom of molybdenum or tungsten is mixed with a lubricating base oil, and compared with the case where a corresponding conventional product is used. Then, they have surprisingly found to have excellent wear resistance and friction characteristics.

The lubricating oil composition of the present invention comprises a lubricating base oil,
By adding ZnDTP and / or zinc dithiocarbamate (ZnDTC) in addition to the metal salt of dithiocarbamate, friction characteristics and wear resistance are further improved. Since the metal salt of dithiocarbamic acid of the present invention is excellent in wear resistance and frictional characteristics, the content of ZnDTP can be reduced and phosphorus can be reduced even when used in combination with ZnDTP. . In addition, a phosphorus-free lubricating oil composition can be obtained by using the metal salt of dithiocarbamic acid of the present invention alone or in combination with ZnDTC without using ZnDTP together.

Further, the lubricating oil composition of the present invention can further reduce the coefficient of friction by adding a fatty acid ester and / or an organic amide compound. Of course, various other additives for lubricating oil can be added to the lubricating oil composition of the present invention as desired. The lubricating oil composition of the present invention can be used in a wide range of fields including engine oils, which are required to have excellent wear resistance and friction characteristics. The present invention has been completed based on these findings.

[0009]

Thus, according to the present invention, the lubricating base oil can be added to the general formula (1)

[0010]

[Chemical 4]

[In the formula, M is a molybdenum atom or a tungsten atom. R ¹ , R ² , R ³ and R ⁴ are each a hydrogen atom, a saturated or unsaturated alkyl group having 1 to 20 carbon atoms,
A cycloalkyl group having 6 to 26 carbon atoms or an alkyl-substituted cycloalkyl group, an aryl group having 6 to 26 carbon atoms, an alkylaryl group or an arylalkyl group, or these hydrocarbon groups, an ester bond, an ether bond, a hydroxyl group or a carboxyl group. The groups are introduced hydrocarbon groups and may be the same or different from each other. However, at least one of these four is an alkyl group having a secondary carbon atom and having 5 to 20 carbon atoms, and the secondary carbon atom is a nitrogen atom (N) in the above formula. Are connected. X ¹ and X ² are oxygen atoms or sulfur atoms.
Y ¹ and Y ² are oxygen atoms or sulfur atoms. ] The lubricating oil composition which contains the dithiocarbamic-acid metal salt (A) represented by these in a ratio of 0.01 to 10 weight% on the basis of the total amount of the composition is provided.

Further, according to the present invention, as a preferred embodiment, the following lubricating oil compositions are provided. In addition to the above-mentioned metal salt of dithiocarbamic acid (A), a lubricating base oil, and further a compound of the general formula (2)

[0013]

[Chemical 5]

(In the formula, R ⁵ , R ⁶ , R ⁷ and R
⁸ is a hydrogen atom, a saturated or unsaturated alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 6 to 26 carbon atoms or an alkyl-substituted cycloalkyl group, an aryl group having 6 to 26 carbon atoms, an alkylaryl group or aryl An alkyl group or a hydrocarbon group in which an ester bond, an ether bond, a hydroxyl group or a carboxyl group is introduced into these hydrocarbon groups, which may be the same or different from each other. ) Zinc dithiophosphate (B) represented by the formula) and the general formula (3)

[0015]

[Chemical 6]

(Wherein R ⁹ , R ¹⁰ , R ¹¹ and R
¹² is a hydrogen atom, a saturated or unsaturated alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 6 to 26 carbon atoms or an alkyl-substituted cycloalkyl group, an aryl group having 6 to 26 carbon atoms, an alkylaryl group or aryl An alkyl group or a hydrocarbon group in which an ester bond, an ether bond, a hydroxyl group or a carboxyl group is introduced into these hydrocarbon groups, which may be the same or different from each other. ) At least one organozinc compound selected from the group consisting of zinc dithiocarbamate (C)
A lubricating oil composition containing 0.01 to 7% by weight based on the total weight of the composition.

The metal salt of dithiocarbamic acid (A)
In the general formula (1), at least two of R ¹ , R ² , R ³ and R ⁴ are alkyl groups having a secondary carbon atom, and at the secondary carbon atom, The lubricating oil composition according to item (1) or (2), which is bonded to a nitrogen atom (N) in the formula. The dithiocarbamic acid metal salt (A) is a compound represented by the general formula (1), wherein at least three of R ¹ , R ² , R ³ and R ⁴ are alkyl groups having a secondary carbon atom, and The lubricating oil composition according to item 1 or 2, wherein the secondary carbon atom is bonded to the nitrogen atom (N) in the formula.

The metal salt of dithiocarbamic acid (A)
In the general formula (1), R ¹ , R ² , R ³ and R ⁴ are alkyl groups having 5 to 20 carbon atoms. In addition to the metal salt of dithiocarbamic acid (A), or in addition to the metal salt of dithiocarbamic acid (A) and zinc dithiophosphate (B) and / or zinc dithiocarbamate (C), a fatty acid ester and /
Alternatively, the lubricating oil composition according to any one of items 1 to 3, which contains an organic amide.

The present invention will be described in detail below. Base Oil The base oil used in the present invention is not particularly limited, and various conventionally known mineral oils and synthetic oils can be used. As mineral oil,
Raffinate obtained by solvent refining a lubricating oil raw material using an aromatic extractant such as phenol or furfural, or hydrotreatment obtained by hydrotreatment using a hydrogenation catalyst such as cobalt or molybdenum with silica-alumina as a carrier. Oil or mineral oil such as lubricating oil fraction obtained by isomerization of wax, specifically, for example, 60 neutral oil, 100 neutral oil, 150 neutral oil, 3
Examples include 00 neutral oil, 500 neutral oil, and bright stock. As the synthetic oil, for example,
Examples thereof include poly-α-olefin, polybutene, alkylbenzene, polyalkylene glycol ester, polyol ester, and dibasic acid ester. These base oils may be used alone or in admixture of two or more, and mineral oil and synthetic oil may be mixed and used. When used as an engine oil, the viscosity of these lubricating base oils usually has a kinematic viscosity of 3 to 20 cSt at 100 ° C.
It is preferably within the range.

Metal salt of dithiocarbamic acid (A) The metal salt of dithiocarbamic acid used in the present invention is an organometallic compound represented by the general formula (1). In the general formula (1), M is a molybdenum atom (Mo) or a tungsten atom (W), and among these, a molybdenum atom is particularly preferable. X ¹ , X ² , Y ¹ and Y ² are
Each is independently an oxygen atom or a sulfur atom. Of these four, the sum of oxygen atoms is generally 0-3 and the sum of sulfur atoms is 1-4.

R ¹ , R ² , R ³ and R ⁴ are hydrogen atoms, saturated or unsaturated alkyl groups having 1 to 20 carbon atoms, and 6 carbon atoms.
To a cycloalkyl group or an alkyl-substituted cycloalkyl group having from 26 to 26, an aryl group having 6 to 26 carbon atoms, an alkylaryl group or an arylalkyl group, or these hydrocarbon groups, an ester bond, an ether bond, a hydroxyl group or a carboxyl group is introduced. And the hydrocarbon groups may be the same or different from each other. Among these, R ^{1 to} R ⁴ are preferably an alkyl group having 5 to 20 carbon atoms, and particularly preferably an alkyl group having 6 to 18 carbon atoms.

However, at least one of R ¹ , R ² , R ³ and R ⁴ has 5 to 20 carbon atoms having a secondary carbon atom.
It is necessary that the compound is an alkyl group of and the secondary carbon atom is bonded to the nitrogen atom (N) in the general formula (1). Preferably, at least two, and more preferably at least three of these four groups are alkyl groups having 5 to 20 carbon atoms and bonded to a nitrogen atom at a secondary carbon atom.

[0023] Such a secondary
As the alkyl group having a carbon atom, for example, 1-methylpentyl, 1-ethylbutyl, 1-methylheptyl, 1-ethylhexyl, 1-methyloctyl, 1-ethylheptyl, 1-methylnonyl, 1-ethyloctyl, 1- Examples include groups such as methylundecyl, 1-ethyldecyl, 1-methylheptadecyl, 1-ethylhexadecyl. The alkyl group having these secondary carbon atoms needs to be bonded to the nitrogen atom (N) in the general formula (1) at the secondary carbon atom, and for example, 1-
In the case of a methylnonyl group, the secondary carbon atom thereof is bonded to the nitrogen atom as shown in the following formula.

[0024]

[Chemical 7]

Therefore, for example, the 2-ethylhexyl group [CH ₃ (CH ₂ ) ₃ CH (C ₂ H ₅ ) CH _2- ] has a secondary carbon atom, but the nitrogen atom is Since they are bonded at a primary carbon atom, they are not included in the alkyl group having the specific secondary carbon atom defined above.

As the group other than the alkyl group having the specific secondary carbon atom, a saturated or unsaturated alkyl group having 5 to 20 carbon atoms, or a hydrocarbon group such as an alkylaryl group is preferable. Specific examples of such a hydrocarbon group include, for example, a saturated alkyl group such as n-hexyl, 2-ethylhexyl, n-octyl, nonyl, decyl, lauryl, tridecyl, oleyl, linoleyl or an unsaturated alkyl group (alkenyl group). ), Alkylaryl groups such as nonylphenyl, and the like. Among these, an alkyl group having 6 to 18 carbon atoms is particularly preferable.

These metal salts of dithiocarbamic acid (A)
Can be used alone or in combination of two or more. The compounding ratio of the metal salt of dithiocarbamic acid (A) is, based on the total amount of the lubricating oil composition, 0.
It is from 01 to 10% by weight, preferably from 0.05 to 7% by weight, more preferably from 0.1 to 5% by weight. If this blending ratio is too small, it is difficult to obtain sufficient frictional properties and wear resistance, and conversely, if it is too large, it is uneconomical and wear resistance may decrease.

Zinc dithiophosphate (B) and dithiocarba
Zinc Minate (C) In the present invention, various lubricating oil additives can be added in addition to the dithiocarbamic acid metal salt (A).
Among them, particularly when used in combination with the zinc dithiophosphate (B) represented by the general formula (2) and / or the zinc dithiocarbamate (C) represented by the general formula (3), for the purpose of the present invention. It is possible to further improve certain wear resistance and the effect of reducing the friction coefficient. In the general formula (2), R
^{5 to} R ⁸ are preferably hydrocarbon groups having 2 to 13 carbon atoms, particularly alkyl groups. In the general formula (3), R ⁹
~ R ¹² is preferably a hydrocarbon group having 2 to 13 carbon atoms, particularly an alkyl group.

The compounding ratio of zinc dithiophosphate (B) and / or zinc dithiocarbamate (C) is 0.01 to 7% by weight, preferably 0.03 to 5 based on the total amount of the lubricating oil composition. %, And more preferably about 0.05 to 2% by weight. If this blending ratio is too small, the combined effect with the metal salt of dithiocarbamic acid (A) is small, and it is difficult to obtain sufficient wear resistance and the effect of reducing the friction coefficient. It is economical and there is a risk that the frictional characteristics will deteriorate.

Other Additives The lubricating oil composition of the present invention may contain various additives depending on the field of application such as engine oil or if desired. As such an additive, for example,
Friction reducers, metal detergents, ashless detergent dispersants, antioxidants, viscosity index improvers, rust inhibitors, defoamers, corrosion inhibitors, pour point depressants, anti-wear agents other than the above, etc. You can

The friction reducing agent is preferably a fatty acid ester such as a monoester or diester of fatty acid and glycerin, a monoester or diester of fatty acid and sorbitan, or a fatty acid amide such as oleic acid amide or lauric acid amide. Fatty acid ester
When used in an amount of usually 0.01 to 10% by weight (based on the total amount of the composition), preferably 0.05 to 5% by weight, the wear resistance and frictional properties are further improved. When the organic amide compound is used in an amount of usually 0.01 to 5% by weight (based on the total amount of the composition), preferably 0.05 to 2% by weight, it suppresses copper corrosiveness and, moreover, the friction coefficient from the initial stage. Can be reduced.

The fatty acid ester and organic amide compound will be described more specifically as follows. The fatty acid glyceride is, for example, a monoester or diester represented by the following general formulas (4) and (5).

[0033]

[Chemical 8]

[0034]

[Chemical 9] (In these formulas, R ¹³ , R ¹⁴ and R ¹⁵ have 8 to 2 carbon atoms.
2 is a saturated or unsaturated alkyl group. )

The fatty acid ester may be used alone or in combination of two or more kinds. When the metal salt of dithiocarbamic acid (A) is used in combination with the fatty acid ester, the abrasion resistance and the frictional properties are further improved as compared with the case where they are used alone. In particular, metal salts of dithiocarbamic acid (A) and zinc dithiophosphate (B) and /
Alternatively, when a fatty acid ester is further added to the combined use system with zinc dithiocarbamate (C), it is possible to obtain a lubricating oil composition having improved wear resistance and friction characteristics and a significantly reduced friction coefficient. The organic amide compound is a compound represented by the following general formula (6).

[0036]

[Chemical 10]

(In the formula, R ¹⁶ and R ¹⁷ are a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 6 to 26 carbon atoms, an aryl group having 6 to 26 carbon atoms, an alkylaryl group or an aryl group. Alkyl group or 2 to 2 carbon atoms
30 alkylene oxide groups, which may be the same or different from each other. R ¹⁸ is a hydrogen atom, having 1 to 2 carbon atoms
0 alkyl group, cycloalkyl group having 6 to 26 carbon atoms,
An aryl group having 6 to 26 carbon atoms, an alkylaryl group or an arylalkyl group, or a hydrocarbon group containing an ester bond, an ether bond, a hydroxyl group or a carboxyl group. In the general formula (6), the alkylene oxide group is a group represented by the following general formula (7) or (8).

[0038]

[Chemical 11]

[0039]

[Chemical 12] (In these formulas, R ¹⁹ and R ²⁰ are a hydrogen atom or a methyl group, and n is an integer of 1 to 10.)

In the general formula (6), R ¹⁶ and R ¹⁷ are preferably a hydrogen atom, an alkyl group having 2 to 8 carbon atoms, or 8 carbon atoms.
To 14 cycloalkyl groups, C 8-14 alkylaryl groups, and n = 1-5 alkylene oxide groups. R ¹⁸ is preferably a saturated or unsaturated alkyl group having 6 to 18 carbon atoms, a cycloalkyl group having 12 to 24 carbon atoms, or an alkylaryl group having 12 to 24 carbon atoms.

Examples of the metal detergent include barium (Ba), calcium (Ca), magnesium (Mg).
Examples thereof include phenates, sulfonates, phosphonates, and the like. Among these, overbased Ca sulfonate, Mg sulfonate, Ca phenate, or neutral Ca sulfonate is particularly preferable. The metal detergent is usually used in a proportion of 0.1 to 10% by weight (based on the total amount of the composition). As the ashless detergent dispersant, for example, benzylamine, a boron derivative of benzylamine,
Examples thereof include alkenyl succinimide and alkenyl succinimide boron derivatives. The ashless detergent dispersant is usually 0.5 to 15% by weight (based on the total amount of the composition).
Used in proportion.

Examples of the antioxidant include amine-based antioxidants such as alkylated diphenylamine, phenyl-α-naphthylamine and alkylated-α-naphthylamine, 2,6-di-t-butylphenol, 4,4′- Examples thereof include phenolic antioxidants such as methylenebis- (2,6-ditertiarybutylphenol). The antioxidant is usually 0.05 to 2.0% by weight.
It is used at a ratio of (composition total amount basis).

Examples of the viscosity index improver include polymethylmethacrylate type, polyisobutylene type, ethylene-propylene copolymer system, styrene-butadiene hydrogenated copolymer system, etc., and usually 0.5 to 35% by weight. It is used at a ratio of (composition total amount basis). Examples of the rust preventive agent include alkenyl succinic acid and its partial ester, and the like, which can be appropriately added. Examples of the defoaming agent include dimethylpolysiloxane and polyacrylate, which can be appropriately added.

[0044]

EXAMPLES The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. The methods for measuring the physical properties are as follows. <Friction / Abrasion Properties> Using a shell four-ball test, the wear scar diameter (mm) and the friction coefficient 30 minutes after the start of the test were measured. The test conditions are as follows. Load: 40 kg Oil temperature: 90 ° C Rotation speed: 1800 rpm Test time: 30 minutes

Example 1 Lubricating base oils shown in Table 1 and various compositions
Each test oil was prepared by mixing the minutes. Each component used is
It is as follows. (1) Base oil Mineral oil: 150 neutral oil; Kinematic viscosity at 100 ° C
Is 5.1 cSt (mm²/ S) Synthetic oil: 80% by weight of poly-α-olefin and diisodecyl
Mixed oil with 20% by weight of luadipate (2) Molybdenum dithiocarbamate: In general formula (1)
By the way, X¹And X²Is an oxygen atom (O), and Y¹And Y²But
Molybde sulfide dithiocarbamate, which is a sulfur source (S)
Used. Hydrocarbon group = p-C ₈~ C₁₃Alkyl: Commercially available primary
(Primary) alkyl group (mixture of 8 to 13 carbon atoms
Molybde sulfurized dithiocarbamate having an alkyl group)
Hydrocarbon group = p-C₁₃Alkyl: commercially available primary (pr
imary) disulfide having an alkyl group (having 13 carbon atoms)
Molybdenum thiocarbamate Hydrocarbon group = 1-methylheptyl: R¹~ R^FourIs 1-me
Molybde sulfide dithiocarbamate, a tylheptyl group
Hydrocarbon group = 1-methylnonyl: R¹~ R^FourIs 1-meth
Molybdenum sulfurized dithiocarbamate, which is a nononyl group Hydrocarbon group = p-C₁₃50% alkyl and 1-methylno
Nil 50%: R¹~ R^FourIs a primary alkyl group (having 1 carbon atom
3) 50-50 mixed alkyl of 1-methylnonyl
Molybdenum sulfurized dithiocarbamate (3) Zinc dithiophosphate: commercially available i-C₃/ S-C₆Al
Kill type (4) Zinc dithiocarbamate: commercially available nC_Five/ I-
C_FiveAlkyl type

The mixing ratio of each additive component in Table 1 is% by weight based on the total amount of the composition, and the balance is base oil (total 1).
00% by weight). The amount of molybdenum sulfide dithiocarbamate added was indicated by the content of molybdenum atoms. The results are shown in Table 1.

[0047]

[Table 1] (Footnote) Experimental examples marked with * are comparative examples, and others are inventive examples.

As is clear from Table 1, the lubricating oil compositions (experiment Nos. 4 to 6, 8 and 10) containing the sulfurized molybdenum dithiocarbamate having a specific secondary alkyl group of the present invention were the conventional ones. Compared with the case of blending molybdenum sulfide dithiocarbamate in which primary carbon atom is bonded to nitrogen atom (Experiment No. 2, 3, 7 and 8), the wear resistance and friction coefficient are remarkably excellent. It shows a reduced descent.

Example 2 Each test oil was prepared by mixing the lubricating base oil shown in Table 2 with each component. Each component used is
It is as follows. (1) The base oil, molybdenum sulfurized dithiocarbamate, and zinc dithiophosphate are the same as those used in Example 1. (2) Fatty acid glyceride:

[0050]

[Chemical 13] (In the formula, R represents an oleyl group.) (3) Organic amide compound: oleic acid amide The results are shown in Table 2.

[0051]

[Table 2] (Footnote) Experimental examples marked with * are comparative examples, and others are inventive examples.

As is clear from the results shown in Table 2, the addition of fatty acid ester or amide further reduces the friction coefficient.

[0053]

EFFECTS OF THE INVENTION According to the present invention, it is possible to provide a lubricating oil composition having remarkably excellent wear resistance and friction characteristics as compared with the conventional metal salt of sulfurized dithiocarbamic acid.
The lubricating oil composition of the present invention can also be extremely low phosphorus-free or phosphorus-free. Therefore, the lubricating oil composition of the present invention can be used in a wide range of fields including lubricating oils for internal combustion engines.

Claims (2)

[Claims] 1. A lubricating base oil having the general formula (1): [In the formula, M is a molybdenum atom or a tungsten atom. R ¹ , R ² , R ³ and R ⁴ are hydrogen atoms and have 1 carbon atom
To saturated or unsaturated alkyl groups having 6 to 20 carbon atoms
An ester bond, an ether bond, a hydroxyl group or a carboxyl group is introduced into a cycloalkyl group of 6 or an alkyl-substituted cycloalkyl group, an aryl group of 6 to 26 carbon atoms, an alkylaryl group or an arylalkyl group, or these hydrocarbon groups. Hydrocarbon groups, which may be the same or different from each other. However, at least one of these four has 5 carbon atoms having a secondary carbon atom.
.About.20 alkyl group, and is bonded to the nitrogen atom (N) in the above formula at its secondary carbon atom. X ¹ and X ² are oxygen atoms or sulfur atoms. Y ¹ and Y ²
Is an oxygen atom or a sulfur atom. ] The metal salt of dithiocarbamic acid (A) represented by
A lubricating oil composition containing 0.01 to 10% by weight. 2. A lubricating base oil, in addition to the metal salt of dithiocarbamic acid (A), further having the general formula (2): (In the formula, R ⁵ , R ⁶ , R ⁷ and R ⁸ are hydrogen atoms,
A saturated or unsaturated alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 6 to 26 carbon atoms or an alkyl-substituted cycloalkyl group, an aryl group having 6 to 26 carbon atoms, an alkylaryl group or an arylalkyl group, or these The hydrocarbon group is a hydrocarbon group in which an ester bond, an ether bond, a hydroxyl group or a carboxyl group is introduced,
They may be the same or different from each other. ) Zinc dithiophosphate (B), represented by the general formula (3) (In the formula, R ⁹ , R ¹⁰ , R ¹¹ and R ¹² are each a hydrogen atom, a saturated or unsaturated alkyl group having 1 to 20 carbon atoms,
A cycloalkyl group having 6 to 26 carbon atoms or an alkyl-substituted cycloalkyl group, an aryl group having 6 to 26 carbon atoms, an alkylaryl group or an arylalkyl group, or these hydrocarbon groups, an ester bond, an ether bond, a hydroxyl group or a carboxyl group. The groups are introduced hydrocarbon groups and may be the same or different from each other. 2.) At least one organozinc compound selected from the group consisting of zinc dithiocarbamate (C) represented by (4) is contained in a proportion of 0.01 to 7% by weight based on the total amount of the composition. Lubricating oil composition.