JPH07150177A - Lubricating oil composition - Google Patents

Abstract

PURPOSE:To obtain a lubricating oil composition which has excellent abrasion resistance, attains a low coefficient of friction, and less corrodes copper by incorporating a specific organomolybdenum compound and a specific metal dithiocarbamate in combination. CONSTITUTION:An organomolybdenum compound selected from hydroxymolybdenum monoglyceride and hydroxymolybdenum diethylateamide is incorporated in an amount of 0.01-10wt.% into a base oil together with 0.5-7wt.% metal dithiocarbamate represented by the formula (wherein M is zinc, copper, nickel, iron, cadmium, silver, lead, antimony, tin, or bismuth; and R<1> to R<4> each is a 1-30C lipophilic group, provided that at least one is a secondary lipophilic group), each ingredient amount being based on the whole composition. According to need, 0.01-5wt.% organic amide is further incorporated. This composition is less apt to corrode copper and attains a reduced coefficient of friction from the beginning of operation.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel lubricating oil composition, and more specifically, for example, engine oil (lubricating oil for internal combustion engine), gear oil, automatic transmission oil (ATF), power steering oil (PS oil). , A spindle oil, a hydraulic oil, an industrial lubricating oil, etc., which has excellent wear resistance, exhibits a low friction coefficient, can reduce fuel consumption, and has improved copper corrosiveness. And a lubricating oil composition having the above characteristics and capable of exhibiting a low friction coefficient from the initial stage of operation (during familiarizing operation).

[0002]

2. Description of the Related Art In recent years, the output of internal combustion engines such as automobile engines has been increasing, and various parts of the engine such as valve trains and cylinders have been exposed to high temperatures, and the number of contacts between metals has increased per unit time. It is coming under severe conditions. Engine oils are used under the harshest conditions among lubricating oils, and in particular, with the miniaturization and high performance of engines (high speed rotation, high output), various and sophisticated performances are required. The basic performance requirements for this engine oil are: friction reduction, wear / seizure prevention, heat
Oxidative deterioration prevention, cleaning / dispersion, corrosion prevention, cooling / sealing function, etc. are mentioned. To satisfy such functions,
Research has been conducted on the use of various additives. For example, as a lubricating oil composition that is particularly excellent in reducing mechanical friction loss of a 4-cycle engine, a kinematic viscosity at 100 ° C. of 3 to 20 is obtained.
(a) Sulfurized oxymolybdenum organophosphorodithioate (hereinafter, referred to as M
oDTP) and / or sulfurized oxymolybdenum dithiocarbamate (hereinafter abbreviated as MoDTC)
0.2-5 wt%, (b) zinc dithiophosphate 0.1-7 wt%, (c) calcium alkylbenzene sulfonate 0.1-20 wt%, and (d) alkenyl succinimide and / or alkenyl A lubricating oil composition has been proposed which comprises 1 to 15% by weight of a boron compound derivative of succinimide (Japanese Patent Publication No. 3-23595). According to this lubricating oil composition, the friction coefficient in the mixed / boundary region can be reduced to about 1/3 that of the conventional engine oil. On the other hand, it is one of the important characteristics of the lubricating oil that it does not corrode the metal inside the engine during use. It is thought that the cause of corrosion is due to free sulfur, lower sulfur compounds, or acidic substances, but since the copper plate is most sensitive to these, generally, regarding the corrosiveness of lubricating oil,
The corrosiveness to the copper plate is evaluated. Nitrogen-based metal deactivators such as benzotriazole are usually added to the lubricating oil to reduce the copper corrosiveness. However, when many of these additives are used, the sealing rubber is hardened, which causes an unfavorable situation. To do. Also, to reduce friction, MoDTP and M
oDTC as disclosed in the above publication in the range of 0.2-5
Addition of a relatively large amount such as wt% causes a problem that the corrosive action on copper (copper corrosivity) becomes severe. Further, a lubricating oil composition containing an organic molybdenum compound such as MoDTP or MoDTC has a problem that the initial friction coefficient (during familiar running) is high. Lubricating oil additives have the effect of reducing boundary friction by adsorbing on the metal surface to form a boundary lubricating film, but these organic molybdenum compounds are adsorbed on the metal surface until a friction reducing effect is exhibited. It takes a relatively long time. Therefore, when the lubricating oil composition containing the organic molybdenum compound is used as the engine oil, a friction reducing effect is exhibited after the vehicle has run for 2000 to 3000 km, depending on the running conditions of the automobile. However, after such running, the time when the friction reducing effect is expressed and the time when the oil is changed may overlap, and in this case, even if the addition amount of MoDTP or MoDTC is increased, the friction reducing effect should be expressed early. However, on the contrary, there arises a problem that the copper corrosiveness is further increased.

[0003]

Under the circumstances, the present invention is excellent in wear resistance, has a low friction coefficient, can save fuel consumption, and has improved copper corrosion. Another object of the present invention is to provide a lubricating oil composition having the above characteristics, and a lubricating oil composition having the above characteristics and capable of exhibiting a low friction coefficient from the initial stage of operation.

[0004]

As a result of intensive studies to develop a lubricating oil composition having the above-mentioned preferable properties, the present inventors have found that oxymolybdenum monoglyceride and oxymolybdenum diethylate amide have sulfur in the molecule. Focusing on the fact that it does not contain atoms, it does not increase the copper corrosivity unlike MoDTP and MoDTC, and by combining this with a metal salt of dithiocarbamic acid having a secondary alkyl group, a lubricating base oil By blending in a predetermined ratio to each, excellent wear resistance, and exhibiting a low friction coefficient, it is possible to obtain a lubricating oil composition having less copper corrosiveness, and further, an organic amide compound in a predetermined ratio. It has been found that by blending, the above-mentioned characteristics can be obtained and the friction coefficient at the initial stage of operation can be reduced. The present invention has been completed based on such findings. That is, the present invention relates to a lubricating base oil, and based on the total weight of the composition, at least one organic molybdenum compound 0.01 to 10 selected from (A) oxymolybdenum monoglyceride and oxymolybdenum diethylate amide. % By weight, and (B) general formula [1]

[0005]

[Chemical 3]

(M in the formula represents zinc, copper, nickel, iron, cadmium, silver, lead, antimony, tin or bismuth, and R ¹ , R ² , R ³ and R ⁴ each independently have 1 to 1 carbon atoms.
30 lipophilic groups, at least one of these four lipophilic groups being a secondary lipophilic group) and containing 0.5 to 7% by weight of a metal salt of dithiocarbamic acid represented by the formula: Based on the total weight of the composition, based on the total weight of the lubricating oil composition and the lubricating base oil, 0.01 to 10% by weight of the component (A), 0.5 to 7% by weight of the component (B), and (C). The present invention provides a lubricating oil composition containing 0.01 to 5% by weight of an organic amide compound. Hereinafter, the present invention will be described in detail. The base oil used in the lubricating oil composition of the present invention is not particularly limited, and those conventionally proposed as base oils for lubricating oil, such as mineral oil and synthetic oil, are used.

[0007] Examples of the mineral oil include 60 neutral oil, 100 neutral oil, 150 neutral oil, 300 neutral oil, 500 neutral oil, and bristock, which are obtained by solvent refining or hydrotreating. Alternatively, two or more kinds may be mixed and used at an appropriate ratio. On the other hand, as synthetic oil,
Examples thereof include poly α-olefin oligomer, polybutene, alkylbenzene, alkyldiphenyl, polyol ester, polyglycol ester, dibasic acid ester, phosphoric acid ester, silicone oil, and the like, and these may be used alone or in combination of two or more. May be mixed and used at an appropriate ratio. Further, the mineral oil and the synthetic oil may be mixed and used. The base oil used in the lubricating oil composition of the present invention has a kinematic viscosity at a temperature of 100 ° C. of 3 to 20 mm ² /
s, preferably in the range of 4 to 15 mm ² / s is suitable.

In the composition of the present invention, oxymolybdenum monoglyceride or oxymolybdenum diethylate amide (hereinafter sometimes abbreviated as MoOxide compound) is used as the component (A). The oxymolybdenum monoglyceride has the general formula [2]

[Chemical 4] Oxymolybdenum diethylate amide is represented by the general formula [3]

[Chemical 5] It is represented by.

In the above general formulas [2] and [3], R
Is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or 2 to 2 carbon atoms
20 alkenyl group, C6-C26 cycloalkyl group, C6-C26 aryl group, C7-26 alkylaryl group or arylalkyl group, or ester bond, ether bond, alcohol group or carboxyl group It is a hydrocarbon group containing. Preferable examples of R include alkyl groups having 6 to 18 carbon atoms and 6 to 8 carbon atoms.
It is an alkenyl group having 18 carbon atoms, a cycloalkyl group having 12 to 24 carbon atoms or an alkylaryl group having 12 to 24 carbon atoms. Preferred examples thereof include alkyl groups having 6 to 18 carbon atoms such as n-hexyl group, 2-ethylhexyl group, n-octyl group, nonyl group, decyl group, lauryl group, tridecyl group, oleyl group and linoleyl group. Alternatively, an alkenyl group, a nonylphenyl group, or the like having 3 to 1 carbon atoms.
Mention may be made of alkylaryl groups having 8 alkyl groups. The MoAxide-based compound as the component (A) may be used alone or in combination of two or more, and the compounding amount thereof is 0.1 based on the total weight of the composition.
It is necessary to select in the range of 01 to 10% by weight, preferably 0.05 to 8% by weight. If the blending amount is less than 0.01% by weight, a sufficient friction reducing effect is not exhibited and 10
When it exceeds the weight%, the effect of reducing friction is not improved for that amount. In the lubricating oil composition of the present invention, (B)
General formula [1] as a component

[0010]

[Chemical 6]

A metal salt of dithiocarbamic acid represented by the formula (hereinafter sometimes abbreviated as M-DTC) is used.
In the above general formula [1], M is zinc, copper, nickel,
It is iron, cadmium, silver, lead, antimony, tin or bismuth. Further, R ¹ , R ² , R ³ and R ⁴ are each a lipophilic group having 1 to 30 carbon atoms, at least one of which is the second
Primary lipophilic groups, preferably at least two are secondary lipophilic groups, the rest including primary lipophilic groups. More preferred lipophilic groups are at least three of which are secondary alkyl groups. The R ¹ , R ² , R ³ and R ⁴ may be the same or different. Examples of the lipophilic group having 1 to 30 carbon atoms include an alkyl group having 1 to 30 carbon atoms, an alkenyl group having 2 to 30 carbon atoms, a cycloalkyl group having 6 to 30 carbon atoms, and an aryl group having 6 to 30 carbon atoms. , Carbon number 7 ~
Examples thereof include an alkylaryl group having 30 carbon atoms, an arylalkyl group having 7 to 30 carbon atoms, or a hydrocarbon group having an ester bond, an ether bond, an alcohol group or a carboxyl group.

In the composition of the present invention, in the M-DTC represented by the above general formula [1], those in which the average carbon number of the four lipophilic groups is more than 1 and 5 or less are dissolved in the lubricating base oil. In order to enhance the properties and improve the abrasion resistance and the like, it is advantageous to react with an oil-soluble amine compound and to perform a complexing treatment, if desired. When the average number of carbon atoms of the four lipophilic groups of the M-DTC is 1 (when all the lipophilic groups are methyl groups), the resulting complex is a lubricating oil even when reacted with an oil-soluble amine compound. Since the solubility in the base oil is poor, a homogeneous lubricating oil composition cannot be obtained. M-DTC is
Since it exerts its function by being adsorbed on the metal surface, it cannot be expected to have a sufficient effect if it is melted too much, but it cannot be used unless it is melted. The lower limit of the average carbon number of the lipophilic group is preferably 2 or more from the viewpoint of both functions such as solubility and abrasion resistance. Those having an average carbon number of four lipophilic groups of more than 5 have good solubility in the lubricating base oil without forming a complex, but may be used after being subjected to a complexing treatment if necessary. The M-DTC is preferably one in which all of the four lipophilic groups are the same hydrocarbon group from the viewpoints of ease of production and abrasion resistance, and in particular, the four lipophilic groups are alkyl groups having 3 to 6 carbon atoms. Those that are groups are preferred. A more preferable lipophilic group is an alkyl group having 3 to 4 carbon atoms. Further, as the metal atom (M), zinc is preferable from the viewpoint of easy availability and wear resistance.

The M-DTC can be produced by a known method. For example, zinc diisopropyldithiocarbamate can be produced by reacting diisopropylamine, carbon disulfide and sodium hydroxide to prepare sodium diisopropyldithiocarbamate, and then reacting with zinc nitrate. This M-DTC
Examples of the oil-soluble amine compound used for the complexation include polyalkenylsuccinimide-based and alkylbenzylamine-based ashless detergent dispersants, alkylamines, alkyldiamines, and alkylpolyamines. In order to form a complex of M-DTC and the oil-soluble amine compound in advance, a method of adding both to the lubricating base oil at a high concentration ratio and heating is preferable. For example, M
-2 to 7% by weight of DTC and 2 to 2% of oil-soluble amine compound
A lubricating oil composition containing 25% by weight and an oil-soluble amine compound in an amount of 1 to 10 parts by weight relative to 1 part by weight of M-DTC is preferably 100 to 230 ° C., more preferably 150 to 200 ° C. When stirred for preferably 1 to 60 minutes, more preferably 1 to 30 minutes, both of them form a complex and uniformly dissolve in the lubricating base oil. As the heating temperature is increased, the complex is formed in a shorter time to be uniformly dissolved.
If the obtained high-concentration complex solution is diluted with a lubricating base oil,
It is possible to easily obtain a uniform lubricating oil composition containing both in a desired ratio.

In the lubricating oil composition of the present invention, the component (B) M-DTC may be used alone or in combination of two or more, and based on the total weight of the composition. It is necessary to add 0.5 to 7% by weight, preferably 1 to 5% by weight. If the blending amount is less than 0.5% by weight, the effect of abrasion resistance is not sufficiently exerted,
If it exceeds 7% by weight, the solubility tends to decrease.
In addition to secM-DTC's function as an extreme pressure agent,
It also functions as an antioxidant and corrosion inhibitor. In the lubricating oil composition of the present invention, an organic amide compound can be used as the component (C), if desired. This organic amide compound has the general formula [4]

[0015]

[Chemical 7]

Is a compound represented by: In the general formula [4], R ⁵ and R ⁶ are each a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, a cycloalkyl group having 6 to 26 carbon atoms, and 6 to 6 carbon atoms. Two
A 6-aryl group, an alkylaryl group or an arylalkyl group having 7 to 26 carbon atoms or an alkylene oxide group having 2 to 30 carbon atoms, which may be the same or different. R ⁷ is a hydrogen atom, having 1 to 1 carbon atoms
An alkyl group having 20 carbon atoms, an alkenyl group having 2 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 having 7 to 26 carbon atoms, an arylalkyl group or an ester bond, It is a hydrocarbon group containing an ether bond, an alcohol group or a carboxyl group. Here, the alkylene oxide group is represented by the general formula [5] or [6]

[0017]

[Chemical 8]

(Wherein R'is a hydrogen atom or a methyl group, n
Is an integer of 1 to 10). In the general formula [4], preferred R ⁵ and R ⁶ are a hydrogen atom, an alkyl group having 2 to 8 carbon atoms, a cycloalkyl group having 8 to 14 carbon atoms, an alkylaryl group having 8 to 14 carbon atoms, n is an alkylene oxide group of 1 to 5. Also,
R ⁷ is preferably an alkyl group having 6 to 18 carbon atoms,
An alkenyl group having 6 to 18 carbon atoms, a cycloalkyl group having 12 to 24 carbon atoms, and an alkylaryl group having 12 to 24 carbon atoms. Specific examples of such an organic amide compound include oleic acid amide and lauric acid amide. These may be used alone or in combination of two or more. In the lubricating oil composition of the present invention, the organic amide compound as the component (C) is 0.01 to 5% by weight, preferably 0.05 to 5% by weight based on the total weight of the composition.
It is blended in a ratio of 2% by weight. By blending this organic amide compound, the friction coefficient can be reduced from the initial stage of operation while suppressing copper corrosiveness. If the blending amount is less than 0.01% by weight, the effect of reducing the friction coefficient from the initial stage of operation is sufficiently exhibited, and if it exceeds 5% by weight, the effect is not improved for the amount.

The lubricating oil composition of the present invention contains various additives conventionally used in lubricating oils, such as other extreme pressure agents, ashless detergent dispersants, and oxidizing agents, as long as the object of the present invention is not impaired. An inhibitor, a metal detergent, a metal deactivator, a viscosity index improver, a pour point depressant, a rust preventive, a defoaming agent, a corrosion inhibitor and the like can be appropriately added. Other extreme pressure agents include
For example, organic molybdenum compounds such as MoDTC and MoDTP can be mentioned. However, when the use ratio of these organic molybdenum compounds increases, copper corrosiveness becomes remarkable. Examples of the ashless detergent dispersant include succinimide-based, succinamide-based, benzylamine-based, and ester-based ones, and a boron-containing ashless detergent-dispersant can also be used. These are usually used in a proportion of 0.5 to 7% by weight. Examples of the antioxidant include amine-based antioxidants such as alkylated diphenylamine, phenyl-α-naphthylamine, and alkylated-α-naphthylamine, 2,6-ditertiarybutylphenol,
Examples thereof include phenolic antioxidants such as 4,4′-methylenebis- (2,6-ditertiarybutylphenol), which are usually used in a proportion of 0.05 to 2.0% by weight. .

Examples of the metal detergent include Ca-sulfonate, Mg-sulfonate, Ba-sulfonate,
There are Ca-phenate, Ba-phenate and the like, which are usually used in a proportion of 0.1 to 5.0% by weight, and examples of the metal deactivator include, for example, benzotriazole, benzotriazole derivatives and benzotriazole derivatives. Examples thereof include thiazole, benzothiazole derivative, triazole, triazole derivative, dithiocarbamate, dithiocarbamate derivative, indazole and indazole derivative, and these are usually used in a proportion of 0.005 to 0.3% by weight. As the viscosity index improver, for example,
Examples thereof include polymethacrylate type, polyisobutylene type, ethylene-propylene copolymer system, styrene-butadiene hydrogenated copolymer system, etc., and these are usually 0.5 to 3
Used in a proportion of 5% by weight. Furthermore, as a rust preventive agent,
For example, alkenyl succinic acid or a partial ester thereof can be used, and examples of the defoaming agent can include dimethyl polysiloxane and polyacrylate, which can be appropriately added. The lubricating oil composition of the present invention can be prepared by blending a base oil with a predetermined amount of each of the various additives described above and uniformly mixing them. The lubricating oil composition of the present invention includes, for example, automobile engine oil, gear oil, ATF, P
It is preferably used as S oil, spindle oil, hydraulic oil, industrial lubricating oil and the like.

[0021]

The present invention will be described in more detail by way of examples, which should not be construed as limiting the invention thereto. The performance of the lubricating oil composition was determined by the method shown below. (1) Coefficient of Friction The coefficient of friction was measured using a microvibration type friction tester (SRV). The SRV tester has a diameter of 1 /
2-inch copper ball (SUJ specified in JIS G-4805)
-2) is used as a lower test piece made of steel (JIS G-48
The disc of SUJ-2) specified in 05 was used. The sample oil was dropped on the lower test piece, and the upper test piece was vibrated in parallel with the lower test piece while being pressed against the lower test piece by applying a load from above the upper test piece. The lateral load applied to the lower test piece was measured to calculate the friction coefficient (μ). The friction coefficient was measured after 5 minutes from the start of vibration of the upper test piece and 2
Two times after 0 minutes. The test conditions are as follows. Load: 100N Temperature: 130 ° C Frequency: 8Hz Amplitude: 4mm

(2) Corrosion A corrosiveness test was conducted in accordance with JIS K-2513 "Petroleum product copper plate corrosion test method" at a test temperature of 100 ° C, a test time of 3 hours, and a test tube method. The discolored state of the copper plate was observed and the corrosiveness was evaluated by the subdivision symbols 1a to 4c. Note that the smaller the number of the subdivision symbol, the smaller the corrosiveness, and the corrosiveness increases in the alphabetical order. A specific evaluation example is as follows. 1a: Light orange, almost the same color as the polished copper plate 1b: Dark orange 3a: Reddish brown pattern on brass color

Examples 1 to 4, Comparative Examples 1 to 3 Mineral oil (150 neutral mineral oil, kinematic viscosity at 100 ° C. 5.
1 mm ² / s), based on the total weight of the composition, 4% by weight of Ca-sulfonate, 5% by weight of succinimide, 0.5% by weight of alkylated diphenylamine, 0.3% by weight of 2,6-di-t-butylphenol and A lubricating oil composition was prepared by blending 0.02% by weight of 5-methylbenzotriazole and each component shown in Table 1, and the performance thereof was evaluated. The results are shown in Table 1. Each component is as follows.

(1) MoOxide compound

[Chemical 9] (2) MoDTC

[Chemical 10] 2EH: 2-ethylhexyl group, and so on (3) MoDTP

[Chemical 11] (4) sec-ZnDTC

[Chemical 12] (Of R ^{1 to} R ⁴ , two are isopropyl groups and the rest are n.
-Propyl group) (5) Ca-sulfonate

[Chemical 13] (6) Succinimide

[Chemical 14] PiB: polyisobutylene

[0025]

[Table 1]

[0026]

EFFECTS OF THE INVENTION According to the present invention, a lubricating oil composition having excellent wear resistance, a low coefficient of friction, capable of reducing fuel consumption, improved copper corrosion, and the above-mentioned characteristics are provided. Further, it is possible to provide a lubricating oil composition capable of exhibiting a low friction coefficient from the initial stage of operation.

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display area C10N 10:04 10:08 10:10 10:12 10:16 30:06 30:12 40:04 40:06 40:08 40:25

Claims (2)

[Claims] 1. Based on the total weight of the composition, 0.01 to 10 parts by weight of at least one organic molybdenum compound selected from (A) oxymolybdenum monoglyceride and oxymolybdenum diethylate amide, based on the total weight of the composition. %, And (B) general formula [1] (M in the formula is zinc, copper, nickel, iron, cadmium,
Indicates silver, lead, antimony, tin or bismuth, R ¹ ,
R ² , R ³ and R ⁴ are each independently a lipophilic group having 1 to 30 carbon atoms, and at least one of these four lipophilic groups is a secondary lipophilic group) A lubricating oil composition comprising 0.5 to 7% by weight of a metal salt of dithiocarbamic acid. 2. At least one organic molybdenum compound selected from the group consisting of (A) oxymolybdenum monoglyceride and oxymolybdenum diethylate amide, based on the total weight of the composition, based on the total weight of the lubricating base oil, and 0.01 to 10 parts by weight. %, (B) General formula [1] (M in the formula is zinc, copper, nickel, iron, cadmium,
Indicates silver, lead, antimony, tin or bismuth, R ¹ ,
R ² , R ³ and R ⁴ are each independently a lipophilic group having 1 to 30 carbon atoms, and at least one of these four lipophilic groups is a secondary lipophilic group) A lubricating oil composition comprising 0.5 to 7% by weight of a metal salt of dithiocarbamic acid and 0.01 to 5% by weight of an organic amide compound (C).