JPH07286190A - Lubricating oil composition - Google Patents

Abstract

PURPOSE:To obtain an lubricating oil composition comprising a specific lubricating oil base oil, a specific diarylamine compound and a specific molybdenum compound in a specified ratio, excellent in heat resistance, oxidation stability, and low abrasion resistance, and suitable for internal combustion engines, etc. CONSTITUTION:This lubricating oil composition comprises (A) a lubricating oil base oil containing <=3wt.% of aromatic components, >=20wt.% of monocyclic naphthene components, <=50ppm of sulfur content and <=50ppm of nitrogen content, and having a viscosity of 2-50mm<2>/s at 100 deg.C, (B) one or more kinds of diarylamine compounds of formulas I (R<1> to R<4> are H, 1-18C hydrocarbon) and II (R<5>, R<6> are R<1>) in an amount of 0.05-3wt.% based on the whole weight of the composition, and (C) one or more kinds of molybdenum compounds of formulas III (R<7>, R<8> are 5-23C hydrocarbon; m+n=4), IV (R<9>, R<10> are 1-18C hydrocarbon; x +y=4), and V (R<11>, R<12> are 1-30C hydrocarbon; X, Y are O, S) in an amount of 50-2000ppm (as molybdenum) based on the whole weight of the composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel lubricating oil composition, and more particularly, it has high heat resistance, high oxidative stability and low friction, and has an internal combustion engine, automatic transmission, shock absorber, power steering, etc. The present invention relates to a lubricating oil composition, which is preferably used as a lubricating oil for internal combustion engines.

[0002]

2. Description of the Related Art Conventionally, lubricating oils have been used in internal combustion engines, drivetrain devices such as automatic transmissions, shock absorbers, power steering systems, gears, etc. in order to ensure smooth operation. In particular, lubricating oil for internal combustion engines (engine oil) mainly lubricates various sliding parts, such as piston rings and cylinder liners, bearings for crankshafts and connecting rods (connecting rods), valve trains including cams and valve lifters, etc. It functions to cool the engine, cleanly disperse combustion products, and prevent rust and corrosion. As described above, lubricating oils for internal combustion engines are required to have various performances, and in recent years, high performances have been required as the performances, output power, and operating conditions of internal combustion engines have become more severe. . Therefore,
In order to satisfy such required performance, the lubricating oil for internal combustion engine may be, for example, an antiwear agent, a metal detergent, an ashless dispersant,
Various additives such as antioxidants are blended. As a basic function of a lubricating oil for an internal combustion engine, it is important to operate the engine smoothly under all conditions to prevent wear and seizure. Most of the engine lubrication part is in a fluid lubrication state, but boundary lubrication is likely to occur at the valve operating system and the top and bottom dead center of the piston, and the wear prevention property under such boundary lubrication is generally zinc dithiophosphate ( ZnDTP)
And zinc dithiocarbamate (ZnDTC). By the way, in an internal combustion engine, energy loss is large in a friction portion where lubricating oil is involved.
As a measure to reduce friction loss and fuel consumption, a friction modifier (F
(M: Friction modifier), and lubricating oils in which various additives are combined are used (for example, Japanese Patent Publication No. 3-23595). Lubricating oils for internal combustion engines of automobiles are operated at various oil temperatures, rotational speeds, and loads. Therefore, in order to further improve fuel consumption, it is necessary to have excellent friction characteristics under a wide range of use conditions. further,
In addition to the above-mentioned properties, the properties required of the lubricating oil for an internal combustion engine include high heat resistance, high oxidative stability, and appropriate viscosity characteristics.

[0003]

Under these circumstances, the present invention has excellent low friction properties, high heat resistance, high oxidative stability, and moderate viscosity properties, and is particularly useful for internal combustion. The purpose of the present invention is to provide a lubricating oil composition suitable as a lubricating oil for engines.

[0004]

As a result of intensive studies to develop a lubricating oil composition having the above-mentioned preferable properties, the inventors of the present invention have found that the lubricating oil having a specific property with a low content of aromatic components. For base oil, specific amine-based antioxidant and sulfurized oxymolybdenum dithiocarbamate (MoDTC)
It was found that the object can be achieved by a composition containing a sulfurized oxymolybdenum organophosphorodithioate (MoDTP) and a sulfurized oxymolybdenum thioxanthogenate (MoDTX) in a predetermined ratio, and based on this finding. Based on this, the present invention has been completed.

That is, the present invention is as follows: (1) (A) aromatic component is 3 wt% or less, mono-naphthene component is 20 wt% or more, sulfur content is 50 wtppm or less, and nitrogen content is 50 wtppm or less. And (B) a general formula based on the total weight of the composition for a lubricating base oil having a viscosity of ² to 50 mm ² / s at a temperature of 100 ° C.

[Chemical 6] (In the formula, R ¹ , R ² , R ³ and R ⁴ are each a hydrogen atom or a hydrocarbon group having 3 to 18 carbon atoms, and they may be the same or different from each other. At least one of which is a hydrocarbon group) and the general formula

[Chemical 7] At least one selected from diarylamines represented by the formula (R ⁵ and R ⁶ in the formula are a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms) is contained in an amount of 0.05 to 3% by weight. (C) General formula

[Chemical 8] (In the formula, R ⁷ and R ⁸ are each a hydrocarbon group having 5 to 23 carbon atoms, and they may be the same or different, and m and n have a sum of 4 respectively. Oxymolybdenum dithiocarbamate represented by the general formula

[Chemical 9] (In the formula, R ⁹ and R ¹⁰ are each a hydrocarbon group having 1 to 18 carbon atoms, and they may be the same or different, and x and y have a sum of 4 respectively. Is a positive integer) such as sulfurized oxymolybdenum organophosphorodithioate represented by the general formula

[Chemical 10] (In the formula, R ¹¹ and R ¹² are each a hydrocarbon group having 1 to 30 carbon atoms, and they may be the same or different, and X and Y are an oxygen atom or a sulfur atom, 50 to 2 in terms of molybdenum amount of at least one selected from sulfurized oxymolybdenum dithioxanthogenates represented by the same or different).
The present invention relates to a lubricating oil composition containing 000 ppm by weight.

Further, in a preferred embodiment of the present invention, (2) the lubricating base oil comprises 3% by weight or less of aromatic components, 20% by weight or more of mono-naphthene components, and 97% by weight or more of saturated components. The lubricating oil composition according to claim 1, which is a certain hydrotreated oil, (3) The lubricating base oil is a hydrotreated oil, and the diarylamines have at least one alkyl group having 3 to 18 carbon atoms. A lubricating oil composition according to claim 1 or 2, which is diphenylamine and phenyl-α-naphthylamine having an alkyl group having 3 to 18 carbon atoms, and which contains sulfurized oxymolybdenum dithiocarbamate, (4) sulfurized oxymolybdenum The lubricating oil composition according to claim 1, 2 or 3, wherein the organophosphorodithioate has an alkyl group having 8 to 18 carbon atoms, and (5) sulfurized oxymolybdenum. First term thio xanthogenate having an alkyl group having 8 to 18 carbon atoms, the second term,
Examples of the method include reducing the fuel consumption by using the lubricating oil composition according to item 3 or 4 and (6) the lubricating oil composition according to item 1 in an internal combustion engine. it can.

The present invention will be described in detail below. In the lubricating oil composition of the present invention, as the lubricating base oil of the component (A), the aromatic component is 3% by weight or less, and the mono-naphthene component is 2%.
It is 0% by weight or more, the sulfur content is 50 ppm by weight or less, the nitrogen content is 50 ppm by weight or less, and the viscosity at a temperature of 100 ° C. is in the range of ² to 50 mm ² / s. The preferred content of the mono-naphthene component is 25 to 40
It is in the range of% by weight. Content of the aromatic component is 3% by weight
If it exceeds, the heat resistance, oxidation stability, and friction characteristics of the resulting lubricating oil composition will deteriorate. If the content of the one-part naphthene component does not reach 20% by weight, the compatibility with the seal rubber is insufficient. If the viscosity is less than 2 mm ² / s, the oil film is not sufficiently formed and the evaporation loss is large, and if it exceeds 50 mm ² / s, the power loss due to the viscous resistance is too large, which is not preferable. Further, when the sulfur content or the nitrogen content exceeds 50 ppm by weight, the oxidation stability and the friction characteristics are deteriorated. As the lubricating base oil, any mineral oil or synthetic oil can be used as long as it has the above-mentioned properties. Specific examples of the base oil are obtained by solvent refining a lubricating oil raw material derived from naphthene base crude oil and paraffin base crude oil under atmospheric pressure and vacuum distillation with an aromatic extraction solvent such as phenol, furfural or N-methylpyrrolidone. A hydrotreated oil obtained by hydrotreating the resulting raffinate or lubricating oil feedstock including a hydrocracking reaction is included. According to any manufacturing method, steps such as a dewaxing step, a hydrorefining step, and a clay treatment step can be arbitrarily adopted according to a conventional method. Particularly preferred lubricating base oils are hydrocracked oils and wax isomerized oils.

In the composition of the present invention, as the amine-based antioxidant of the component (B), a compound of the general formula

[Chemical 11] And the general formula

[Chemical 12] At least one selected from the diarylamines represented by is used. In the general formula [1],
R ¹ , R ² , R ³ and R ⁴ are each a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms. R ¹ , R ² , R ³ and R ⁴ may be the same or different, but at least one of them is an alkyl group having 3 to 18 carbon atoms. is necessary. The carbon number 3-18
The alkyl group may be linear, branched or cyclic, and examples thereof include various propyl groups, various butyl groups, various amyl groups, various hexyl groups,
Various heptyl groups, various octyl groups, various nonyl groups, various decyl groups, various undecyl groups, various dodecyl groups, various tridecyl groups, various tetradecyl groups, various pentadecyl groups, various hexadecyl groups, various heptadecyl groups, various octadecyl groups, and further Examples thereof include a cyclohexyl group, a cyclooctyl group and a cyclododecyl group. Further, in the general formula [2], R ⁵ and R ⁶ are hydrogen atoms or hydrocarbon groups having 1 to 18 carbon atoms. A preferred hydrocarbon group is an alkyl group, and the alkyl group having 3 to 18 carbon atoms may be linear, branched or cyclic. Examples of such a hydrocarbon group include those represented by the general formula [1 It includes the same as those exemplified in the description of R ¹ to R ⁴ in. Specifically, p, p'-dibutyldiphenylamine, p, p'-dipentyldiphenylamine,
p, p'-dihexyldiphenylamine, p, p'-diheptyldiphenylamine, p, p'-dioctyldiphenylamine, p, p'-dinonyldiphenylamine, monooctyldiphenylamine, monononyldiphenylamine,
Tetrabutyldiphenylamine, tetrahexyldiphenylamine, tetraoctyldiphenylamine, tetranonyldiphenylamine, mixed alkyldiphenylamine having 4 to 9 carbon atoms, phenyl-α-naphthylamine, phenyl-β-naphthylamine, butylphenyl-α-naphthylamine, butylphenyl-β- Naphthylamine,
Pentylphenyl-α-naphthylamine, pentylphenyl-β-naphthylamine, hexylphenyl-α-naphthylamine, hexylphenyl-β-naphthylamine, heptylphenyl-α-naphthylamine, heptylphenyl-β-naphthylamine, octylphenyl-α
-Naphthylamine, octylphenyl-β-naphthylamine, nonylphenyl-α-naphthylamine, nonylphenyl-β-naphthylamine and the like are included. Particularly preferred diarylamines include p, p′-dioctyldiphenylamine, phenyl-α-naphthylamine and alkylphenyl-α-naphthylamine.

In the composition of the present invention, one kind of alkyldiphenylamine represented by the above general formula [1] may be used as the amine-based antioxidant of the component (B).
Two or more kinds may be used in combination, and one kind of the phenyl-α-naphthylamines represented by the general formula [2] may be used, or two or more kinds may be used in combination. Furthermore, one or more alkyldiphenylamines represented by the general formula [1] and one or more phenyl-α-naphthylamines represented by the general formula [2] may be used in combination. In the present invention, the amine-based antioxidant of the component (B) is 0.05 based on the total weight of the composition.
It is necessary to blend in the range of 3 to 3% by weight, preferably 0.2 to 2% by weight. If the amount is less than 0.05% by weight, sufficient oxidative stability cannot be obtained, and if it exceeds 3% by weight, the effect is not improved for the amount. In the composition of the present invention, as the friction modifier of the component (C), a general formula

[Chemical 13] Oxymolybdenum dithiocarbamate (MoDTC) represented by the general formula

[Chemical 14] Sulfurized oxymolybdenum organophosphorodithioate (MoDTP) represented by

[Chemical 15] At least one selected from sulfurized oxymolybdenum dithioxanthogenate (MoDTX) represented by

In the above general formula [3], R ⁷ and R ⁸ are each a hydrocarbon group having 5 to 23 carbon atoms, and they may be the same or different.
The hydrocarbon group having 5 to 23 carbon atoms has 5 to 2 carbon atoms.
And 3 linear or branched alkyl groups or alkenyl groups, C 6-23 cycloalkyl groups, aryl groups, alkylaryl groups or arylalkyl groups. The preferred hydrocarbon group has 8 to 23 carbon atoms. Specific examples of such compounds include 2-ethylhexyl group, n-octyl group, nonyl group, decyl group, lauryl group, tridecyl group, palmityl group, stearyl group, oleyl group, eicosyl group, butylphenyl group and nonylphenyl group. Is mentioned. Further, m and n are positive integers such that the sum thereof is 4. on the other hand,
In the general formula [4], R ⁹ and R ¹⁰ are each a hydrocarbon group having 1 to 18 carbon atoms, and they may be the same or different. Suitable hydrocarbon groups are those having 3 to 18 carbon atoms. The carbon number 3 to 1
As the hydrocarbon group having 8 carbon atoms, a linear or branched alkyl group or alkenyl group having 3 to 18 carbon atoms, having 6 carbon atoms
To C18 cycloalkyl group, C6-18 aryl group, C7-18 alkylaryl group or arylalkyl group. Specific examples of such groups include isopropyl group, n-propyl group, n-butyl group, isobutyl group, sec-butyl group, amyl group, hexyl group, cyclohexyl group, 2-ethylhexyl group, n.
-Octyl group, nonyl group, decyl group, lauryl group, tridecyl group, palmityl group, stearyl group, oleyl group,
Examples thereof include a butylphenyl group and a nonylphenyl group. Further, x and y are positive integers such that their sum is 4. In the general formula [5], R ¹¹
And R ¹² are each a hydrocarbon group having 1 to 30 carbon atoms, and they may be the same or different from each other. A preferred hydrocarbon group is one having 3 to 20 carbon atoms, and a linear or branched alkyl group or alkenyl group having 5 to 20 carbon atoms, a cycloalkyl group having 6 to 20 carbon atoms, and a carbon atom having 6 to 20 carbon atoms. Examples thereof include an aryl group, an alkylaryl group and an arylalkyl group. Specifically, isopropyl group, n-propyl group, isobutyl group, n-butyl group, sec-butyl group, amyl group, hexyl group, cyclohexyl group, 2-ethylhexyl group, n-octyl group,
Examples thereof include nonyl group, decyl group, lauryl group, tridecyl group, palmityl group, stearyl group, oleyl group, butylphenyl group and nonylphenyl group. Further, X and Y are oxygen atoms or sulfur atoms, and may be the same or different. In the composition of the present invention, one type of MoDTC represented by the general formula [3] may be used, or 2
One or more kinds may be used in combination, and one kind of MoDTP represented by the general formula [4] may be used, or two or more kinds may be used in combination. The MoDTX represented by the general formula [5] can also be used alone or in combination of two or more.

In the composition of the present invention, the friction modifier as the component (C) is 50 to 2000 ppm by weight, preferably 100 to 100, as the amount of molybdenum based on the total weight of the composition.
It is necessary to blend in the range of 0 weight ppm. If the amount of molybdenum is less than 50 ppm by weight, sufficient low frictional properties cannot be obtained, and if it exceeds 2000 ppm by weight, the effect of improving the frictional properties cannot be seen for that amount. The lubricating oil composition of the present invention contains various additives that are conventionally used in lubricating oils, such as metal detergents, ashless detergent dispersants, antiwear agents, and viscosity indexes, as long as the object of the present invention is not impaired. Improvers, pour point depressants, rust inhibitors, corrosion inhibitors, defoamers, other antioxidants and the like can be added as appropriate. As a metallic detergent,
For example, calcium sulfonate, magnesium sulfonate, barium sulfonate, calcium phenate,
Examples include barium phenate, calcium salicylate, magnesium salicylate, etc.
It is used in a proportion of 1 to 5% by weight. Examples of the ashless detergent dispersant include succinimide type, succinic acid amide type, benzylamine type and its boron derivatives, ester type, and the like, and these are usually used in a proportion of 0.5 to 7% by weight. To be done. Examples of the antiwear agent include thiophosphoric acid metal salts (Zn, Pb, Sb, Mo, etc.), thiocarbamic acid metal salts (Zn, etc.), sulfur compounds, phosphoric acid esters, phosphorous acid esters, and the like. However, these are usually used in a proportion of 0.05 to 5.0% by weight. Examples of the viscosity index improver include polymethacrylate type, polyisobutylene type, ethylene-propylene copolymer type,
Styrene-butadiene hydrogenated copolymer system and the like,
These are usually used in a proportion of 0.5 to 35% by weight.
Examples of the rust preventive agent include alkenyl succinic acid and its partial ester, examples of the corrosion inhibitor include benzotriazole and benzimidazole, and examples of the defoaming agent include dimethylpolysiloxane and polyacrylate. These can be added appropriately.

[0012]

EXAMPLES The present invention will be described in more detail by way of examples, which should not be construed as limiting the invention thereto. The oxidation induction time and the friction coefficient of the lubricating oil composition were determined as follows. (1) Friction coefficient (μ) Rotation speed 270 rp by LFW-1 tester shown in FIG.
m, load 30 kgf, oil temperature 120 ° C, time 10 minutes,
LFW-1 using Falex R-type block (made of iron) and Falex S-10 test ring (made of iron)
A friction test was conducted. In FIG. 1, 1 is an S-10 test ring, 2 is an R-type block, and 3 is a strain gauge.
A load is applied to the R-shaped block and the resistance generated when the ring is rotated is detected by a strain gauge to calculate the friction coefficient. The test oil is immersed in about half of the ring. (2) Oxidation induction time (minutes) 20 kgf / cm ² , 2 under oxygen atmosphere by differential thermal analysis
It was determined under the isothermal holding condition of 00 ° C. Examples 1 to 8 and Comparative Examples 1 to 7 Using the base oil having the properties shown in Table 1, lubricating oil compositions having the compositions shown in Table 2 were prepared, and the friction coefficient (μ) and the oxidation induction time (minutes) were prepared. I asked. The results are shown in Table 2.

[0013]

[Table 1]

[0014]

[Table 2]

[0015]

[Table 3]

The lubricating oils of Examples 1 to 8 which are the compositions of the present invention all have a low friction coefficient and a long oxidation induction time. On the other hand, the lubricating oil of Comparative Example 1 has a low friction coefficient, but the oxidation induction time is short, and the lubricating oils of Comparative Examples 2 to 7 are significantly inferior to the lubricating oil of the example in both the friction coefficient and the oxidation induction time. .

[0017]

The lubricating oil composition of the present invention has high heat resistance, high oxidative stability and low friction, and is particularly suitable for use as a lubricating oil for internal combustion engines.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an apparatus used in a LFW-1 friction test.

[Explanation of symbols]

 1 S-test ring 2 R type block 3 Strain meter

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Claims (1)

[Claims] (A) An aromatic component (A) is 3% by weight or less, a mono-naphthene component is 20% by weight or more, a sulfur content is 50% by weight or less, a nitrogen content is 50% by weight or less, and a temperature is 100.
Based on the total weight of the composition, (B) the general formula: ## STR1 ## for a lubricating base oil having a viscosity of ² to 50 mm ² / s at (In the formula, R ¹ , R ² , R ³ and R ⁴ are each a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms, and they may be the same or different, At least one of which is a hydrocarbon group) and a compound of the general formula At least one selected from diarylamines represented by the formula (R ⁵ and R ⁶ in the formula are a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms) is contained in an amount of 0.05 to 3% by weight. And (C) the general formula: (In the formula, R ⁷ and R ⁸ are each a hydrocarbon group having 5 to 23 carbon atoms, and they may be the same or different, and m and n have a sum of 4 respectively. Oxymolybdenum dithiocarbamate represented by the general formula: (In the formula, R ⁹ and R ¹⁰ are each a hydrocarbon group having 1 to 18 carbon atoms, and they may be the same or different, and x and y have a sum of 4 respectively. A positive integer) such as sulfurized oxymolybdenum organophosphorodithioate represented by the general formula: (In the formula, R ¹¹ and R ¹² are each a hydrocarbon group having 1 to 30 carbon atoms, and they may be the same or different, and X and Y are an oxygen atom or a sulfur atom, 50 to 20 at least one selected from the sulfurized oxymolybdenum dithioxanthogenates represented by the same or different ones) may be used.
A lubricating oil composition, characterized in that it is contained in an amount of 00 ppm by weight.