JP7429509B2 - lubricating oil composition - Google Patents

Description

TECHNICAL FIELD This invention relates to lubricating oil compositions.

In recent years, the development of direct injection gasoline engines (downsizing engines) equipped with superchargers such as turbochargers has progressed at a rapid pace. While direct injection in gasoline engines has the advantage of improving fuel efficiency, it has the disadvantage of generating particulate matter (PM) and other substances contained in exhaust gas, similar to diesel engines. Therefore, direct injection gasoline engines equipped with an exhaust gas treatment device including a gasoline particulate filter (GPF) in addition to an exhaust gas purification catalyst are becoming popular.
There is concern that lubricating oil compositions may have an adverse effect on such exhaust gas treatment devices. Specifically, when using a lubricating oil composition containing a metal-based detergent, there is a concern that the filter may be clogged by metal components derived from the metal-based detergent. As a countermeasure for this, it is required to reduce the sulfated ash content of lubricating oil compositions.

For example, Patent Document 1 discloses a lubricating oil composition for internal combustion engines in which a calcium-based detergent is blended so that the amount of sulfated ash is 0.7% by mass or less. Furthermore, from the viewpoint of suppressing poisoning of the exhaust gas purification catalyst, lubricating oil compositions are also required to have a reduced phosphorus content.
In other words, lubricating oil compositions are required not only to reduce the sulfated ash content but also to reduce the phosphorus content.

Japanese Patent Application Publication No. 2000-256690

However, as a result of studies conducted by the present inventors, a lubricating oil composition with reduced sulfated ash and phosphorus content was found to be effective in low-speed pre-ignition (Low-Speed Pre-ignition) during low-speed operation in a direct injection gasoline engine equipped with a supercharger. ignition (hereinafter referred to as "LSPI"). LSPI is a phenomenon in which ignition occurs earlier than the set ignition timing in low-speed operating conditions, and abnormal combustion may occur within the engine cylinder due to the ignition. The occurrence of LSPI may be a factor that has a negative impact on improving fuel efficiency or causes engine failure. Therefore, it is believed that there is an urgent need to provide a lubricating oil composition that can suppress the generation of LSPI.

Furthermore, from the viewpoint of extending the life of exhaust gas treatment equipment, it is also required to further reduce the sulfated ash content of lubricating oil compositions. However, if the sulfated ash content of the lubricating oil composition is further reduced, it becomes difficult to ensure high temperature cleanliness.

Furthermore, lubricating oil compositions are required not only to have high-temperature detergency but also to have a reduced coefficient of friction. However, as a result of studies conducted by the present inventors, it was found that it is difficult to reduce the coefficient of friction while maintaining good high-temperature cleanliness.

The present invention provides a lubricating oil composition that can suppress the generation of LSPI while having a low sulfated ash content and a low phosphorus content, and can reduce the coefficient of friction while providing good high-temperature cleanliness. The challenge is to provide the following.

In order to solve the above problems, the inventors of the present invention have conducted extensive studies. As a result, it has been found that a lubricating oil composition containing a certain amount or more of phosphorus while reducing the phosphorus content suppresses the generation of LSPI.
As a result of further intensive studies, the present inventor has found that a lubricating oil composition containing a specific calcium-based detergent and a specific amount of a specific aromatic carboxylic acid ester derivative has a low sulfated ash content of 0.3% by mass or less. However, it has been found that the high temperature cleanliness is good. In addition, it has been discovered that lubricating oil compositions containing specific amounts of specific molybdenum compounds can effectively reduce the coefficient of friction without deteriorating high temperature cleanliness.
Based on these findings, the present inventor conducted further intensive studies and completed the present invention.

That is, the present invention provides the following [1] to [10].
[1] From base oil (A), aromatic carboxylic acid ester derivative (B1) represented by the following general formula (I), and aromatic carboxylic acid ester derivative (B2) represented by the following general formula (II) Calcium containing one or more selected aromatic carboxylic acid ester derivatives (B), an oxymolybdenum complex of a basic nitrogen compound (C1), and a calcium-based detergent (D1) having a base value of 200 mgKOH/g or more A lubricating oil composition containing a detergent (D),

[In the general formula (I), x and y are integers satisfying 1≦x≦3 and 1≦y≦3, respectively. R ¹ and R ² each independently represent an alkyl group having 9 to 20 carbon atoms. When x≧2, a plurality of R ¹ 's may be the same or different. When y≧2, a plurality of R ² may be the same or different. ]

[In the general formula (II), m, n, о, and p are respectively 1≦m≦2, 0≦n≦2, 2≦(m+n)≦4, 1≦о≦3, 1≦p≦ It is an integer that satisfies 3. R ³ and R ⁴ each independently represent an alkyl group having 9 to 20 carbon atoms. When о≧2, a plurality of R ³ 's may be the same or different. When p≧2, the plurality of R ^4s may be the same or different. ]
The content of the aromatic carboxylic acid ester derivative (B) is 1.5% by mass or more based on the total amount of the lubricating oil composition,
The content of molybdenum atoms derived from the oxymolybdenum complex (C1) of the basic nitrogen compound is 0.025% by mass or more based on the total amount of the lubricating oil composition,
The content of calcium atoms derived from the calcium-based detergent (D) is 0.020% by mass or more and less than 0.080% by mass, based on the total amount of the lubricating oil composition,
The sulfated ash content is 0.3% by mass or less,
A lubricating oil composition, wherein the content of phosphorus atoms is 0.020% by mass or more and 0.040% by mass or less, based on the total amount of the lubricating oil composition.
[2] [1] above, wherein the content of calcium atoms derived from the calcium-based detergent (D1) is 0.020% by mass or more and less than 0.080% by mass, based on the total amount of the lubricating oil composition. The lubricating oil composition described in .
[3] The content of calcium atoms derived from the calcium-based detergent (D2) having a base value of less than 200 mgKOH/g is less than 0.025% by mass, based on the total amount of the lubricating oil composition. 1] or the lubricating oil composition according to [2].
[4] The content ratio [Ca D2 /Ca _D1 ] of the calcium atoms (Ca D2 ) derived from the calcium-based detergent ( _D2 ) and the calcium atoms (Ca _D1 ) derived from the calcium-based detergent ( _D1 ) is The lubricating oil composition according to [3] above, which has a mass ratio of less than 0.31.
[5] The content of Mo atoms derived from molybdenum dithiocarbamate (MoDTC) (C2) is less than 0.020% by mass based on the total amount of the lubricating oil composition, [1] to [4] above. The lubricating oil composition according to any one of the above.
[6] Content ratio of Mo atoms (Mo C2 ) derived from the molybdenum dithiocarbamate (MoDTC) ( _C2 ) and molybdenum atoms (Mo _C1 ) derived from the oxymolybdenum complex (C1) of the basic nitrogen compound [ The lubricating oil composition according to [5] above, wherein the mass ratio of Mo _C2 /Mo _C1 is less than 1.0.
[7] The lubricating oil composition according to any one of [1] to [6] above, further comprising zinc dithiophosphate (ZnDTP) (E).
[8] The lubricating oil composition according to any one of [1] to [7] above, which is used in an internal combustion engine.
[9] The lubricating oil composition according to any one of [1] to [7] above, which is used in an internal combustion engine equipped with a gasoline particulate filter (GPF).
[10] The lubricating oil composition according to [9] above, which is used in a direct injection internal combustion engine equipped with a supercharger.

According to the present invention, a lubricating oil can suppress the generation of LSPI while having a low sulfated ash content and a low phosphorus content, and can also reduce the coefficient of friction while providing good high-temperature cleanliness. It becomes possible to provide a composition.

In this specification, the lower and upper limits described in stages for preferred numerical ranges (for example, ranges of content, etc.) can be independently combined. For example, from the description "preferably 10 to 90, more preferably 30 to 60", the "preferable lower limit (10)" and "more preferable upper limit (60)" are combined to become "10 to 60". be able to. Similarly, in this specification, numerical values of "more than", "less than", "less than", and "greater than" in the description of numerical ranges are numerical values that can be combined arbitrarily.

[Lubricating oil composition]
The lubricating oil composition of the present embodiment includes a base oil (A), an aromatic carboxylic acid ester derivative (B), an oxymolybdenum complex of a basic nitrogen compound (C1), and a base number of 200 mgKOH/g or more. A lubricating oil composition containing a calcium-based detergent (D) containing a calcium-based detergent (D1),
The aromatic carboxylic acid ester derivative (B) is an aromatic carboxylic acid ester derivative (B1) represented by the following general formula (I) and an aromatic carboxylic acid ester derivative (B2) represented by the following general formula (II). ), and

[In the general formula (I), x and y are integers satisfying 1≦x≦3 and 1≦y≦3, respectively. R ¹ and R ² each independently represent an alkyl group having 9 to 20 carbon atoms. When x≧2, a plurality of R ¹ 's may be the same or different. When y≧2, a plurality of R ² may be the same or different. ]

[In the general formula (II), m, n, о, and p are respectively 1≦m≦2, 0≦n≦2, 2≦(m+n)≦4, 1≦о≦3, 1≦p≦ It is an integer that satisfies 3. R ³ and R ⁴ each independently represent an alkyl group having 9 to 20 carbon atoms. When о≧2, a plurality of R ³ 's may be the same or different. When p≧2, the plurality of R ^4s may be the same or different. ]
The content of the aromatic carboxylic acid ester derivative (B) is 1.5% by mass or more based on the total amount of the lubricating oil composition,
The content of molybdenum atoms derived from the oxymolybdenum complex (C1) of the basic nitrogen compound is 0.025% by mass or more based on the total amount of the lubricating oil composition,
The content of calcium atoms derived from the calcium-based detergent (D) is 0.020% by mass or more and less than 0.080% by mass, based on the total amount of the lubricating oil composition,
The sulfated ash content is 0.3% by mass or less,
The lubricating oil composition has a phosphorus atom content of 0.020% by mass or more and 0.040% by mass or less, based on the total amount of the lubricating oil composition.

In order to solve the above problems, the present inventor has made extensive studies and found that while there is a risk of LSPI occurring if the phosphorus content in a lubricating oil composition is reduced too much, the phosphorus atom content is It has been found that a lubricating oil composition containing 0.020% by mass or more and 0.040% by mass or less based on the total amount can suppress the generation of LSPI. In other words, it has been found that ensuring a certain amount or more of phosphorus atom content while reducing the phosphorus content is effective in suppressing the generation of LSPI.
Further, as a result of further intensive studies by the present inventors in order to solve the above problems, a lubricating oil composition containing a specific calcium-based detergent and a specific amount of a specific aromatic carboxylic acid ester derivative has been developed. It has been found that high temperature cleanliness is good even with a low sulfated ash content of 3% by mass or less.
On the other hand, when molybdenum dialkyldithiocarbamate (MoDTC), a general-purpose friction modifier, was added to a lubricating oil composition to reduce the coefficient of friction, it was found that the high-temperature detergency of the lubricating oil composition tended to deteriorate. The present inventor has come to the knowledge.
Therefore, as a result of further various studies, the present inventors found that a lubricating oil composition containing a certain amount or more of an oxymolybdenum complex of a basic nitrogen compound maintains a good state without deteriorating high-temperature cleanliness and has a friction coefficient. We have come to the conclusion that this can be effectively reduced.
Based on these findings, the present inventor conducted further intensive studies and completed the present invention.

In addition, in the following explanation, base oil (A), aromatic carboxylic acid ester derivative (B), oxymolybdenum complex of basic nitrogen compound (C1), and calcium-based detergent having a base number of 200 mgKOH/g or more ( The calcium-based detergent (D) containing D1) is also referred to as component (A), component (B), component (C1), and component (D), respectively.
In addition, in the following description, the aromatic carboxylic acid ester derivative (B1) represented by the above general formula (I) and the aromatic carboxylic acid ester derivative (B2) represented by the above general formula (II) are, respectively, Also referred to as component (B1) and component (B2).

In the lubricating oil composition of the present embodiment, the total content of component (A), component (B), component (C1), and component (D) is preferably 70% by mass or more, more preferably 75% by mass or more. , more preferably 80% by mass or more.
Moreover, in the lubricating oil composition of this embodiment, the upper limit of the total content of component (A), component (B), component (C1), and component (D) may be 100% by mass. However, if the lubricating oil composition contains other lubricating oil additives other than component (B), component (C1), and component (D), component (A), component (B), and component ( The upper limit of the total content of C1) and component (D) may be adjusted in relation to the other lubricating oil additives, preferably 95% by mass or less, more preferably 90% by mass or less, and Preferably it is 85% by mass or less.

Each component contained in the lubricating oil composition of this embodiment will be explained below.

<Base oil (A)>
The lubricating oil composition of this embodiment contains base oil (A). As the base oil (A), one or more selected from mineral oils and synthetic oils conventionally used as base oils for lubricating oils can be used without particular limitation.

Mineral oils include, for example, atmospheric residual oil obtained by atmospheric distillation of crude oil such as paraffinic crude oil, intermediate crude oil, naphthenic crude oil, etc.; vacuum residual oil obtained by vacuum distillation of the atmospheric residual oil; The vacuum residue is subjected to one or more refining treatments such as solvent deasphalting, solvent extraction, hydrofinishing, hydrocracking, advanced hydrocracking, solvent dewaxing, catalytic dewaxing, and hydroisomerization dewaxing. Examples include the mineral oil obtained.

Examples of synthetic oils include polyα-olefins such as α-olefin homopolymers and α-olefin copolymers (for example, α-olefin copolymers having 8 to 14 carbon atoms such as ethylene-α-olefin copolymers). -Olefin; Isoparaffin; Various esters such as polyol esters and dibasic acid esters; Various ethers such as polyphenyl ether; Polyalkylene glycol; Alkylbenzene; Alkylnaphthalene; Wax produced from natural gas by the Fischer-Tropsch method etc. , Gas To Liquids WAX), etc., which are obtained by isomerizing GTL base oil.

The base oil used in this embodiment is preferably a base oil classified into Group II or III of the API (American Petroleum Institute) base oil category, and more preferably a base oil classified into Group III.

As the base oil (A), one type selected from mineral oils may be used alone, or two or more types may be used in combination. Moreover, one type selected from synthetic oils may be used alone, or two or more types may be used in combination. Furthermore, one or more mineral oils and one or more synthetic oils may be used in combination.

There are no particular restrictions on the kinematic viscosity and viscosity index of the base oil (A), but from the viewpoint of improving fuel efficiency and wear resistance, the kinematic viscosity and viscosity index are preferably within the following ranges. .
The kinematic viscosity of the base oil (A) at 40° C. (hereinafter also referred to as "40° C. kinematic viscosity") is preferably 2.0 mm ² /s to 100.0 mm ² /s, and 5.0 mm ² /s to 80 mm 2 /s. .0 mm ² /s is more preferable, 10.0 mm ^{2 /s} to 60.0 mm ² /s is even more preferable, 15 mm ² /s to 40 mm ² /s is even more preferable, and 15 mm ² /s to 30 mm ² /s is more preferable. Even more preferred.
The kinematic viscosity at 100° C. (hereinafter also referred to as "100° C. kinematic viscosity") of the base oil (A) is preferably 2.0 mm ² /s to 20.0 mm ² /s, and 3.0 mm ² /s to 9 0 mm ² /s is more preferable, 3.5 mm ^{2 /s} to 7.0 mm ² /s is still more preferable, and 3.5 mm ^{2 /s} to 5.0 mm ² /s is even more preferable.
The viscosity index of the base oil (A) is preferably 80 or more, more preferably 90 or more, even more preferably 100 or more, and even more preferably 105 or more.
The 40° C. kinematic viscosity, the 100° C. kinematic viscosity, and the viscosity index can be measured or calculated in accordance with JIS K 2283:2000.
Moreover, when the base oil (A) is a mixed base oil containing two or more types of base oils, it is preferable that the kinematic viscosity and viscosity index of the mixed base oil are within the above ranges.

In the lubricating oil composition of this embodiment, the content of the base oil (A) is not particularly limited, but from the viewpoint of making it easier to exhibit the effects of the present invention, the content of the base oil (A) is based on the total amount (100% by mass) of the lubricating oil composition. , is preferably 60% by mass to 90% by mass, more preferably 65% by mass to 85% by mass, even more preferably 70% by mass to 80% by mass.

<Aromatic carboxylic acid ester derivative (B)>
The lubricating oil composition of this embodiment contains an aromatic carboxylic acid ester derivative (B). When the lubricating oil composition contains the aromatic carboxylic acid ester derivative (B), high-temperature cleanliness can be improved.
The aromatic carboxylic acid ester derivative (B) is an aromatic carboxylic acid ester derivative (B1) represented by the following general formula (I) and an aromatic carboxylic acid ester derivative (B2) represented by the following general formula (II). One or more types selected from.

[In the general formula (I), x and y are integers satisfying 1≦x≦3 and 1≦y≦3, respectively. R ¹ and R ² each independently represent an alkyl group having 9 to 20 carbon atoms. When x≧2, a plurality of R ¹ 's may be the same or different. When y≧2, a plurality of R ² may be the same or different. ]

[In the general formula (II), m, n, о, and p are respectively 1≦m≦2, 0≦n≦2, 2≦(m+n)≦4, 1≦о≦3, 1≦p≦ It is an integer that satisfies 3. R ³ and R ⁴ each independently represent an alkyl group having 9 to 20 carbon atoms. When о≧2, a plurality of R ³ 's may be the same or different. When p≧2, the plurality of R ^4s may be the same or different. ]

In the above general formulas (I) and (II), examples of the alkyl group having 9 to 20 carbon atoms include hydrocarbon groups such as nonyl group, decyl group, dodecyl group, hexadecyl group, octadecyl group, and eicosyl group. can be mentioned. The alkyl group having 9 to 20 carbon atoms may be a linear alkyl group or a branched alkyl group. When a low viscosity carboxylic acid ester derivative is desired, R ¹ and R ² are preferably linear alkyl groups. Further, the number of carbon atoms in R ¹ and R ² is preferably 10 to 20, more preferably 10 to 18, still more preferably 10 to 16, even more preferably 10 to 14.

Specific examples of the aromatic carboxylic acid ester derivative (B1) represented by the above general formula (I) include (nonylsalicylic acid) nonylphenyl ester, (decylsalicylic acid) decylphenyl ester, (undecylsalicylic acid) undecylphenyl ester , (undecylsalicylic acid) dodecylphenyl ester, (dodecylsalicylic acid) undodecylphenyl ester, (dodecylsalicylic acid) dodecylphenyl ester, (dodecylsalicylic acid) tridodecylphenyl ester, (tridecylsalicylic acid) dodecylphenyl ester, (tridecylsalicylic acid) Tridecyl phenyl ester, (tetradecyl salicylic acid) tetradecyl phenyl ester, (heptadecyl salicylic acid) heptadecyl phenyl ester, (hexadecyl salicylic acid) hexadecyl phenyl ester, (mixed C11 to C15) alkyl salicylic acid, (mixed C11 to C15) Alkylphenyl ester, (mixed C11-C15) alkylsalicylic acid nonylphenyl ester, (mixed C11-C15) alkylsalicylic acid decylphenyl ester, (mixed C11-C15) alkylsalicylic acid undecylphenyl ester, (mixed C11-C15) alkylsalicylic acid dodecyl ester Phenyl ester, (mixed C11-C15) alkylsalicylic acid tridecylphenyl ester, (mixed C11-C15) alkylsalicylic acid tetradecylphenyl ester, (mixed C11-C15) alkylsalicylic acid heptadecylphenyl ester, (mixed C11-C15) alkylsalicylic acid Examples include hexadecyl phenyl ester.
These may be used alone or in combination of two or more.

Specific examples of the aromatic carboxylic acid ester derivative (B2) represented by the above general formula (II) include (nonylsalicylic acid) nonylhydroxyphenyl ester, (decylsalicylic acid) decylhydroxyphenyl ester, (undecylsalicylic acid) undecyl Hydroxyphenyl ester, (undecyl salicylic acid) dodecyl hydroxy phenyl ester, (dodecyl salicylic acid) undecyl hydroxy phenyl ester, (dodecyl salicylic acid) dodecyl hydroxy phenyl ester, (dodecyl salicylic acid) tridecyl hydroxy phenyl ester, (tridecyl salicylic acid) dodecyl hydroxy Phenyl ester, (tridecylsalicylic acid) tridecylhydroxyphenyl ester, (tetradecylsalicylic acid) tetradecylhydroxyphenyl ester, (heptadecylsalicylic acid) heptadecylhydroxyphenyl ester, (hexadecylsalicylic acid) hexadecylhydroxyphenyl ester, (mixed C11 - C15) alkyl salicylic acid nonyl hydroxy phenyl ester, (mixed C11 to C15) alkyl salicylic acid decyl hydroxy phenyl ester, (mixed C11 to C15) alkyl salicylic acid undecyl hydroxy phenyl ester, (mixed C11 to C15) alkyl salicylic acid dodecyl hydroxy phenyl ester, (Mixed C11-C15) Alkyl salicylic acid tridecyl hydroxyphenyl ester, (Mixed C11-C15) Alkyl salicylic acid tetradecyl hydroxyphenyl ester, (Mixed C11-C15) Alkyl salicylic acid heptadecyl hydroxyphenyl ester, (Mixed C11-C15) Alkyl salicylic acid ( (dodecyl dihydroxybenzoic acid) undecylphenyl ester, (dodecyl dihydroxybenzoic acid) dodecylphenyl ester, (dodecyl dihydroxybenzoic acid) tridecylphenyl ester, (tridecyl dihydroxybenzoic acid) dodecylphenyl ester, (tridecyl dihydroxybenzoic acid) tri Decylphenyl ester, (tetradecyl dihydroxybenzoic acid) tetradecylphenyl ester, (heptadecyl dihydroxybenzoic acid) heptaphenyl ester, (hexadecyl dihydroxybenzoic acid) hexadecyl phenyl ester, nonyldihydroxybenzoic acid (mixed C11-C15) alkyl Phenyl ester, decyl dihydroxybenzoic acid (mixed C11-C15) alkyl phenyl ester, undodecyl dihydroxybenzoic acid (mixed C11-C15) alkyl phenyl ester, dodecyl dihydroxybenzoic acid (mixed C11-C15) alkylphenyl ester, tridecyl dihydroxybenzoic acid Acid (mixed C11-C15) alkylphenyl ester, tetradecyldihydroxybenzoic acid (mixed C11-C15) alkylphenyl ester, heptadecyldihydroxybenzoic acid (mixed C11-C15) alkylphenyl ester, hexadecyl dihydroxybenzoic acid (mixed C11-C15) C15) Alkyl phenyl ester, (nonyl dihydroxybenzoic acid) nonyl hydroxy phenyl ester, (decyl dihydroxy benzoic acid) decyl hydroxy phenyl ester, (undodecyl dihydroxy benzoic acid) undodecyl hydroxy phenyl ester, (undecyl dihydroxy benzoic acid) dodecyl hydroxy Phenyl ester, (dodecyl dihydroxybenzoic acid) undecyl hydroxy phenyl ester, (dodecyl dihydroxy benzoic acid) dodecyl hydroxy phenyl ester, (dodecyl dihydroxy benzoic acid) tridecyl hydroxy phenyl ester, (tridecyl dihydroxy benzoic acid) dodecyl hydroxy phenyl ester, (Tridecyl dihydroxybenzoic acid) tridecyl hydroxy phenyl ester, (tetradecyl dihydroxy benzoic acid) tetradecyl hydroxy phenyl ester, (heptadecyl dihydroxy benzoic acid) heptadecyl hydroxy phenyl ester, (hexadecyl dihydroxy benzoic acid) hexadecyl hydroxy phenyl Esters, nonyldihydroxybenzoic acid (mixed C11-C15) alkylhydroxyphenyl ester, decyldihydroxybenzoic acid (mixed C11-C15) alkylhydroxyphenyl ester, undodecyldihydroxybenzoic acid (mixed C11-C15) alkylhydroxyphenyl ester, dodecyl dihydroxy Benzoic acid (mixed C11-C15) alkyl hydroxyphenyl ester, tridecyl dihydroxybenzoic acid (mixed C11-C15) alkyl hydroxyphenyl ester, tetradecyl dihydroxybenzoic acid (mixed C11-C15) alkyl hydroxyphenyl ester, heptadecyl dihydroxybenzoic acid Examples include (mixed C11 to C15) alkyl hydroxy phenyl ester, hexadecyl dihydroxybenzoic acid (mixed C11 to C15) alkyl hydroxy phenyl ester, and the like.
These may be used alone or in combination of two or more.

Furthermore, in the lubricating oil composition of the present embodiment, one or more aromatic carboxylic acid ester derivatives (B1) represented by the above general formula (I) and one or more aromatic carboxylic acid ester derivatives (B1) represented by the above general formula (II) are used. It may be used in combination with one or more selected from aromatic carboxylic acid ester derivatives (B2).

Incidentally, among the aromatic carboxylic acid ester derivative (B1) represented by the above general formula (I) and the aromatic carboxylic acid ester derivative (B2) represented by the above general formula (II), decylphenyl (decylsalicylic acid) ester, (undecylsalicylic acid) undecylphenyl ester, (dodecylsalicylic acid) dodecylphenyl ester, (tridecylsalicylic acid) tridecylphenyl ester, (tetradecylsalicylic acid) tetradecylphenyl ester, (heptadecylsalicylic acid) heptadecylphenyl ester, and (hexadecylsalicylic acid) hexadecyl phenyl ester, and (decylsalicylic acid) decylphenyl ester, (undecylsalicylic acid) undecylphenyl ester, (dodecylsalicylic acid) dodecylphenyl ester, and (tridecyl salicylic acid) One or more types selected from (salicylic acid) tridecyl phenyl ester are more preferable, and (dodecyl salicylic acid) dodecylphenyl ester is even more preferable.

In the lubricating oil composition of this embodiment, the content of the aromatic carboxylic acid ester derivative (B) is 1.5% by mass or more based on the total amount of the lubricating oil composition.
When the content of the aromatic carboxylic acid ester derivative (B) is less than 1.5% by mass based on the total amount of the lubricating oil composition, it becomes difficult to ensure the high temperature cleanliness of the lubricating oil composition.
Here, from the viewpoint of making it easier to improve the high-temperature cleanliness of the lubricating oil composition and to obtain a lubricating oil composition that has better base number maintenance properties, the content of the aromatic carboxylic acid ester derivative (B) is as follows: Preferably 1.8% by mass or more, more preferably 2.0% by mass or more, even more preferably 3.0% by mass or more, even more preferably 4.0% by mass or more, even more preferably 5.0% by mass or more. It is.
Further, the upper limit of the content of the aromatic carboxylic acid ester derivative (B) is usually 20% by mass or less, preferably 10% by mass or less.

<Oxymolybdenum complex (C1) of basic nitrogen compound>
The lubricating oil composition of this embodiment contains an oxymolybdenum complex (C1) of a basic nitrogen compound. When the lubricating oil composition contains the basic nitrogen compound oxymolybdenum complex (C1), the coefficient of friction can be reduced while providing good high-temperature cleanliness.

The oxymolybdenum complex (C1) of a basic nitrogen compound is a reaction product of an acidic molybdenum compound or its salt and a basic nitrogen compound, and the oxymolybdenum complex (C1) is a reaction product of an acidic molybdenum compound or its salt and a basic nitrogen compound. It can be produced by contacting and reacting with a basic nitrogen compound.
Examples of the acidic molybdenum compound include molybdic acid, ammonium molybdate, and alkali metal salts of molybdate.
These may be used alone or in combination of two or more.
Examples of the basic nitrogen compound include succinimide, carbonamide, hydrocarbon monoamine, hydrocarbon polyamine, Mannich hydrochloric acid, phosphonamide, thiophosphonamide, phosphoric acid amide, and the like.
These may be used alone or in combination of two or more.
As the basic nitrogen compound, it is preferable to use succinimide.

As the oxymolybdenum complex (C1) of a basic nitrogen compound, a reaction product of an acidic molybdenum compound or its salt and a basic nitrogen compound may be used as it is, but a sulfide obtained by further reacting with a small amount of sulfur or a sulfur compound may be used. It is preferable to use it as
In the present invention, a sulfide obtained by reacting a reaction product of an acidic molybdenum compound and a basic nitrogen compound with a small amount of sulfur or a sulfur compound is also included in the oxymolybdenum complex (C1) of the basic nitrogen compound.
Here, the oxymolybdenum complex (C1) of the basic nitrogen compound is preferably a low-temperature sulfurization reaction product obtained by low-temperature sulfurization of a reaction product of an acidic molybdenum compound or its salt and succinimide. In addition, from the viewpoint of low sulfurization, it is preferable that the sulfur content of the sulfide is small, and it is more preferable that the sulfur content is 10% or less (based on mass) of the molybdenum atom content.

Further, in the lubricating oil composition of the present embodiment, the content of molybdenum atoms derived from the oxymolybdenum complex (C1) of the basic nitrogen compound is 0.025% by mass or more based on the total amount of the lubricating oil composition. .
If the content of molybdenum atoms derived from the oxymolybdenum complex (C1) of the basic nitrogen compound is less than 0.025% by mass, the coefficient of friction cannot be sufficiently reduced.
Here, the content of molybdenum atoms originating from the oxymolybdenum complex (C1) of the basic nitrogen compound is preferably 0.000% based on the total amount of the lubricating oil composition, from the viewpoint of making it easier to reduce the coefficient of friction. 0.030% by mass or more, more preferably 0.035% by mass or more, still more preferably 0.040% by mass or more.
Further, the upper limit of the content of molybdenum atoms derived from the oxymolybdenum complex (C1) of the basic nitrogen compound is usually 0.200% by mass or less.

In the lubricating oil composition of this embodiment, the content of molybdenum atoms contained in the oxymolybdenum complex (C1) of the basic nitrogen compound is preferably 1.0% based on the total amount of the oxymolybdenum complex (C1) of the basic nitrogen compound. The content is 0% by weight to 10.0% by weight, more preferably 2.0% to 7.5% by weight, even more preferably 4.5% to 6.5% by weight.
In the lubricating oil composition of the present embodiment, the content of sulfur atoms contained in the oxymolybdenum complex (C1) of the basic nitrogen compound is preferably 0. 01% to 2.5% by weight, more preferably 0.05% to 1.5% by weight, even more preferably 0.1% to 0.3% by weight.
In the lubricating oil composition of the present embodiment, the content of nitrogen atoms contained in the oxymolybdenum complex (C1) of the basic nitrogen compound is preferably 0. The content is 1% by weight to 5.0% by weight, more preferably 0.5% to 2.5% by weight, even more preferably 1.0% to 2.0% by weight.
In the lubricating oil composition of the present embodiment, the base value of the oxymolybdenum complex (C1) of the basic nitrogen compound is preferably 1 mgKOH/g to 200 mgKOH/g, more preferably 2 mgKOH/g to 50 mgKOH/g, even more preferably 3mgKOH/g to 25mgKOH/g.

<Calcium-based cleaning agent (D)>
The lubricating oil composition of the present embodiment contains a calcium-based detergent (D) including a calcium-based detergent (D1) having a base value of 200 mgKOH/g or more. When the lubricating oil composition contains the calcium-based detergent (D) including the calcium-based detergent (D1), the high-temperature detergency of the lubricating oil composition can be improved.
When the calcium-based detergent (D) is not contained, high-temperature detergency cannot be sufficiently ensured.
In the lubricating oil composition of the present embodiment, the content of calcium atoms derived from the calcium-based detergent (D) is 0.020% by mass or more and less than 0.080% by mass, based on the total amount of the lubricating oil composition. be.
When the content of calcium atoms derived from the calcium-based detergent (D) is less than 0.020% by mass, it is difficult to ensure high-temperature detergency of the lubricating oil composition. Moreover, if the content of calcium atoms derived from the calcium-based detergent (D) is 0.080% by mass or more, the sulfated ash content of the lubricating oil composition becomes large, which becomes a factor that causes blockage of the GPF.
Here, from the viewpoint of easily reducing the sulfated ash content while ensuring high-temperature cleanliness of the lubricating oil composition, the content of calcium atoms derived from the calcium-based detergent (D) is based on the total amount of the lubricating oil composition. The content is preferably 0.020% by mass to 0.070% by mass, preferably 0.030% by mass to 0.065% by mass, and more preferably 0.035% by mass to 0.055% by mass.

In the lubricating oil composition of this embodiment, the content of the calcium-based detergent (D) may be adjusted so that the content of calcium atoms derived from the calcium-based detergent (D) satisfies the above range. Specifically, the content of the calcium-based detergent (D) is, for example, preferably 0.01% by mass or more and 5.0% by mass or less, more preferably 0.1% by mass, based on the total amount of the lubricating oil composition. % or more and 2.5% by mass or less, more preferably 0.20% by mass or more and 1.5% by mass or less.

(Calcium-based detergent (D1) with a base value of 200 mgKOH/g or more)
Examples of the calcium-based detergent (D1) include calcium sulfonate represented by the following general formula (D1-1), calcium salicylate represented by the following general formula (D1-2), and calcium-based detergent (D1) represented by the following general formula (D1-1). Examples include calcium salts such as calcium phenate represented by -3).
Among these, calcium sulfonate is preferred in terms of better high-temperature cleanliness.
One type of calcium-based detergent (D1) may be used alone, or two or more types may be used in combination.
The calcium-based detergent (D1) is preferably 80% to 100% by mass, more preferably 90% to 100% by mass, and even more preferably 95% to 100% by mass, based on the total amount of the calcium-based detergent (D). % by mass, more preferably 100% by mass.

In the above general formula (D1-3), q is an integer of 0 or more, preferably an integer of 0 or more and 3 or less.
In the above general formulas (D1-1) to (D1-3), each R is independently a hydrogen atom or a hydrocarbon group.
The hydrocarbon group that can be selected as R may have a linear structure, a branched chain, or a ring formation. Among these, a branched hydrocarbon group is preferred.
Examples of the hydrocarbon group include an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, an alkylaryl group, and an arylalkyl group.
Among these, a branched alkyl group is preferred.
The number of carbon atoms in the hydrocarbon group is preferably 3 or more and 26 or less, more preferably 7 or more and 24 or less, and even more preferably 10 or more and 20 or less.
The number of carbon atoms in the branched chain in the branched hydrocarbon group is preferably 1 or more and 8 or less, more preferably 2 or more and 6 or less, and even more preferably 2 or more and 5 or less.

In the lubricating oil composition of the present embodiment, the base value of the calcium-based detergent (D1) is preferably 200 mgKOH/g or more from the viewpoint of suppressing the generation of precipitates while providing good high-temperature detergency. 500 mgKOH/g, more preferably 200 mgKOH/g to 480 mgKOH/g, even more preferably 200 mgKOH/g to 460 mgKOH/g.
In addition, when the calcium-based detergent (D1) is a calcium sulfonate represented by the above general formula (D1-1), the base number of the calcium-based detergent (D1) is preferably from the same viewpoint as above. The range is 300 mgKOH/g to 500 mgKOH/g, more preferably 350 mgKOH/g to 490 mgKOH/g, even more preferably 400 mgKOH/g to 480 mgKOH/g.
Further, when the calcium-based detergent (D1) is a calcium salicylate represented by the above general formula (D1-2), the base number of the calcium-based detergent (D1) is determined from the same viewpoint as above. Preferably 200 mgKOH/g to 400 mgKOH/g, more preferably 200 mgKOH/g to 300 mgKOH/g, still more preferably 200 mgKOH/g to 250 mgKOH/g.

In this specification, the base number of the calcium-based detergent (D1) means the base number measured by the perchloric acid method in accordance with JIS K 2501:2003.

Here, in the lubricating oil composition of the present embodiment, the content of calcium atoms derived from the calcium-based detergent (D1) is 0.020% by mass or more and 0.080% by mass based on the total amount of the lubricating oil composition. Less than is preferred.
When the content of calcium atoms derived from the calcium-based detergent (D1) is less than 0.020% by mass, it is difficult to ensure high-temperature detergency of the lubricating oil composition. In addition, if the content of calcium atoms derived from the calcium-based detergent (D1) is 0.080% by mass or more, the sulfated ash content of the lubricating oil composition will increase, which may cause blockage of the GPF. be.
Here, from the viewpoint of easily reducing the sulfated ash content while ensuring high-temperature cleanliness of the lubricating oil composition, the content of calcium atoms derived from the calcium-based detergent (D1) is based on the total amount of the lubricating oil composition. The content is preferably 0.020% by mass to 0.070% by mass, preferably 0.030% by mass to 0.065% by mass, and more preferably 0.035% by mass to 0.055% by mass.

In the lubricating oil composition of this embodiment, the content of the calcium-based detergent (D1) may be adjusted so that the content of calcium atoms derived from the calcium-based detergent (D1) satisfies the above range. The content of the calcium-based detergent (D1) is, for example, based on the total amount of the lubricating oil composition, preferably 0.01% by mass or more and 5.0% by mass or less, more preferably 0.1% by mass or more and 2.5% by mass. It is not more than 0.20% by mass and not more than 1.5% by mass.

(Calcium-based detergent (D2) with a base value of less than 200 mgKOH/g)
In the lubricating oil composition of the present embodiment, the content of the calcium-based detergent (D2) in the calcium-based detergent (D) may be small from the viewpoint of easily ensuring high-temperature cleanliness of the lubricating oil composition. preferable. Specifically, the content of calcium atoms derived from the calcium-based detergent (D2) is preferably less than 0.025% by mass, more preferably less than 0.020% by mass, based on the total amount of the lubricating oil composition. More preferably, it is less than 0.015% by weight, even more preferably less than 0.010% by weight, even more preferably less than 0.005% by weight.

The calcium-based detergent (D2) includes a calcium sulfonate represented by the above general formula (D1-1), a calcium salicylate represented by the above general formula (D1-2), and a calcium salicylate represented by the above general formula (D1-3). ) Calcium salts such as calcium phenate are mentioned.
Moreover, the base number of the calcium-based detergent (D2) may be less than 100 mgKOH/g, may be less than 50 mgKOH/g, or may be less than 30 mgKOH/g.
Moreover, the base number of the calcium-based detergent (D2) is usually 10 mgKOH/g or more.

Here, in the lubricating oil composition of the present embodiment, calcium atoms (Ca D2 ) derived from the calcium-based detergent ( _D2 ) and calcium-based detergent ( The content ratio [Ca _D2 /Ca _D1 ] with calcium atoms (Ca _D1 ) derived from D1) is preferably less than 0.31, more preferably less than 0.25, and even more preferably It is less than 0.19, even more preferably less than 0.13, even more preferably less than 0.06.

<ZnDTP(E)>
The lubricating oil composition of this embodiment preferably contains ZnDTP (zinc dithiophosphate) (E).
Examples of ZnDTP(E) include zinc dithiophosphate having a primary dialkyl group, zinc dithiophosphate having a secondary dialkyl group, and the like.
ZnDTP(E) may be used alone or in combination of two or more.

The number of carbon atoms in the alkyl group of ZnDTP (E) is not particularly limited and is appropriately selected depending on the purpose, but is preferably 1 or more and 10 or less, more preferably 3 or more and 8 or less. Note that zinc dithiophosphate and the like having a secondary dialkyl group may contain alkyl groups having different numbers of carbon atoms.

In the lubricating oil composition of the present embodiment, the content of phosphorus atoms (EP) derived from ZnDTP (E) is such that the base number is maintained above a certain level while reducing the amount of phosphorus atom discharged, and From the viewpoint of easily suppressing the occurrence of , the content is preferably 0.020% by mass or more and 0.040% by mass or less, more preferably 0.021% by mass or more and 0.036% by mass, based on the total amount of the lubricating oil composition. or less, more preferably 0.022% by mass or more and 0.032% by mass or less.

In the lubricating oil composition of the present embodiment, the content of ZnDTP(E) is preferably adjusted so that the content in terms of phosphorus atoms falls within the above range. Based on the total amount (100% by mass), preferably from 0.28% by mass to 0.57% by mass, more preferably from 0.30% by mass to 0.51% by mass, even more preferably from 0.31% by mass to 0. .45% by mass or less.

<Additives for other lubricating oils>
The lubricating oil composition of this embodiment may contain other lubricating oil additives other than the above-mentioned components as long as the effects of the present invention are not impaired.
Examples of the other lubricating oil additives include antioxidants, ashless dispersants, metal detergents other than calcium detergents (D1), pour point depressants, viscosity index improvers, and preventive agents. Examples include rust agents, antifoaming agents, metal deactivators, demulsifiers, and the like.

(Antioxidant)
Examples of the antioxidant include amine antioxidants, phenolic antioxidants, and the like.
These may be used alone or in combination of two or more.
Here, as the antioxidant, it is preferable to use a combination of one or more selected from amine antioxidants and one or more selected from phenolic antioxidants.
Examples of amine-based antioxidants include diphenylamine-based antioxidants such as diphenylamine, alkylated diphenylamine having an alkyl group having 3 to 20 carbon atoms; α-naphthylamine, alkyl-substituted phenyl-α-naphthylamine having 3 to 20 carbon atoms; Examples include naphthylamine-based antioxidants such as.
Examples of phenolic antioxidants include 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, and octadecyl-3-(3,5-dimethylphenol). Monophenolic antioxidants such as -tert-butyl-4-hydroxyphenyl) propionate; 4,4'-methylenebis(2,6-di-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6 -tert-butylphenol); hindered phenol antioxidants; and the like.

(ashless dispersant)
Examples of ashless dispersants include boron-free succinimides such as boron-free alkenylsuccinimide, boron-containing succinimides such as boron-containing alkenylsuccinimide, benzylamines, boron-containing benzylamines, Examples include succinic acid esters, fatty acids, and monovalent or divalent carboxylic acid amides represented by succinic acid.
These may be used alone or in combination of two or more.
Among these, it is preferable to use boron-free alkenylsuccinimide and boron-containing alkenylsuccinimide, and it is more preferable to use boron-free alkenylsuccinimide and boron-containing alkenylsuccinimide in combination.

(Other metal-based detergents other than calcium-based detergents (D))
Examples of metal-based detergents other than the calcium-based detergent (D) include metal salicylates, metal phenates, and metal sulfonates made of metals other than calcium.
Examples of the metals other than calcium include alkali metals and alkaline earth metals. Specific examples include sodium, magnesium, barium, etc. Among these, magnesium is preferably used.
These may be used alone or in combination of two or more.

(Pour point depressant)
Examples of pour point depressants include ethylene-vinyl acetate copolymers, condensates of chlorinated paraffins and naphthalene, condensates of chlorinated paraffins and phenols, polymethacrylates, polyalkylstyrenes, and the like.
These may be used alone or in combination of two or more.

(Viscosity index improver)
Examples of the viscosity index improver include non-dispersed polymethacrylate, dispersed polymethacrylate, olefin copolymer (e.g., ethylene-propylene copolymer, etc.), dispersed olefin copolymer, and styrene copolymer. (For example, styrene-diene copolymer, styrene-isoprene copolymer, etc.).
These may be used alone or in combination of two or more.
The mass average molecular weight (Mw) of these viscosity index improvers is usually 500 to 1,000,000, preferably 5,000 to 100,000, more preferably 10,000 to 50,000, but It is set appropriately depending on the type of union.
In this specification, the mass average molecular weight (Mw) of each component is a standard polystyrene equivalent value measured by gel permeation chromatography (GPC).

(anti-rust)
Examples of the rust preventive include fatty acids, alkenylsuccinic acid half esters, fatty acid soaps, alkyl sulfonates, polyhydric alcohol fatty acid esters, fatty acid amines, oxidized paraffins, and alkyl polyoxyethylene ethers.
These may be used alone or in combination of two or more.

(antifoaming agent)
Examples of antifoaming agents include silicone oil, fluorosilicone oil, and fluoroalkyl ether.
These may be used alone or in combination of two or more.

(metal deactivator)
Examples of the metal deactivator include benzotriazole compounds, tolyltriazole compounds, thiadiazole compounds, imidazole compounds, and pyrimidine compounds.
These may be used alone or in combination of two or more.

(Demulsifier)
Examples of demulsifiers include anionic surfactants such as castor oil sulfate ester salts and petroleum sulfonates; cationic surfactants such as quaternary ammonium salts and imidazolines; polyoxyalkylene polyglycols and their dicarboxylic acids. esters; alkylene oxide adducts of alkylphenol-formaldehyde polycondensates; and the like.
These may be used alone or in combination of two or more.

The content of the other lubricating oil additives can be adjusted as appropriate within a range that does not impair the effects of the present invention, but for each of them, based on the total amount (100% by mass) of the lubricating oil composition, Usually 0.001% to 15% by mass, preferably 0.005% to 10% by mass, more preferably 0.01% to 7% by mass, and even more preferably 0.03% to 5% by mass. preferable.
In addition, in this specification, the other lubricating oil additives are diluted and dissolved in a part of the base oil (A) described above, taking into consideration handling properties, solubility in the base oil (A), etc. It may be combined with other ingredients in the form of a solution. In such a case, in this specification, the above-mentioned content of the additive as the other component means the content in terms of active ingredients (in terms of resin content) excluding diluent oil.

<Other ingredients>
In addition to the above components, the lubricating oil composition of the present embodiment contains other ester derivatives other than the aromatic carboxylic acid ester derivative (B), and other molybdenum compounds other than the oxymolybdenum complex (C1) of a basic nitrogen compound ( C) may contain a calcium-based detergent (D) other than the calcium-based detergent (D1).
However, it is preferable that the content of the compounds explained below is small, and it is more preferable that the compounds explained below are not included.

(Borate ester (B'))
In the lubricating oil composition of this embodiment, from the viewpoint of ensuring high-temperature cleanliness of the lubricating oil composition, it is preferable that the content of boric acid ester (B') among the ester derivatives is small. Specifically, the content of the boric acid ester (B') is preferably less than 5.0% by mass, more preferably less than 1.0% by mass, and still more preferably 0.0% by mass, based on the total amount of the lubricating oil composition. It is less than 1% by mass, more preferably less than 0.01% by mass, even more preferably free of boric acid ester (B').
Examples of the boric acid ester (B') include borated glycerol monooleate.

(Molybdenum dithiocarbamate (C2))
In the lubricating oil composition of the present embodiment, the content of molybdenum dithiocarbamate (C2) among the molybdenum compounds (C) is small from the viewpoint of reducing the coefficient of friction while ensuring high-temperature cleanliness of the lubricating oil composition. It is preferable. Specifically, the content of molybdenum atoms derived from molybdenum dithiocarbamate (C2) is preferably less than 0.020% by mass, more preferably less than 0.015% by mass, and even more preferably less than 0.015% by mass, based on the total amount of the lubricating oil composition. is less than 0.010% by mass, more preferably less than 0.005% by mass, even more preferably free of molybdenum atoms derived from molybdenum dithiocarbamate (C2).

Examples of molybdenum dithiocarbamate (C2) include dinuclear molybdenum dithiocarbamate containing two molybdenum atoms in one molecule, and trinuclear molybdenum dithiocarbamate containing three molybdenum atoms in one molecule.

Examples of the dinuclear molybdenum dithiocarbamate include compounds represented by the following general formula (C2-1) and compounds represented by the following general formula (C2-2).

In the above general formulas (C2-1) and (C2-2), R ¹¹ to R ¹⁴ each independently represent a hydrocarbon group, and these may be the same or different.
X ¹¹ to X ¹⁸ each independently represent an oxygen atom or a sulfur atom, and may be the same or different. However, at least two of X ¹¹ to X ¹⁸ in formula (C2-1) are sulfur atoms.
The hydrocarbon group that can be selected as R ¹¹ to R ¹⁴ has 6 to 22 carbon atoms.

Examples of the hydrocarbon groups that can be selected as R ¹¹ to R ¹⁴ in the above general formulas (C2-1) and (C2-2) include alkyl groups, alkenyl groups, cycloalkyl groups, aryl groups, and alkylaryl groups. group, arylalkyl group, etc.
Examples of the alkyl group include hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, etc. .
Examples of the alkenyl group include hexenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, undecenyl group, dodecenyl group, tridecenyl group, tetradecenyl group, pentadecenyl group, and the like.
Examples of the cycloalkyl group include cyclohexyl group, dimethylcyclohexyl group, ethylcyclohexyl group, methylcyclohexylmethyl group, cyclohexylethyl group, propylcyclohexyl group, butylcyclohexyl group, heptylcyclohexyl group, and the like.
Examples of the aryl group include a phenyl group, a naphthyl group, an anthracenyl group, a biphenyl group, and a terphenyl group.
Examples of the alkylaryl group include tolyl group, dimethylphenyl group, butylphenyl group, nonylphenyl group, dimethylnaphthyl group, and the like.
Examples of the arylalkyl group include methylbenzyl group, phenylmethyl group, phenylethyl group, diphenylmethyl group, and the like.

Examples of the trinuclear molybdenum dithiocarbamate include compounds represented by the following general formula (C2-3).
Mo ₃ S _k E _m L _n A _p Q _z (C2-3)

In the general formula (C2-3), k is an integer of 1 or more, m is an integer of 0 or more, and k+m is an integer of 4 to 10, preferably 4 to 7. n is an integer of 1 to 4, and p is an integer of 0 or more. z is an integer from 0 to 5 and includes non-stoichiometric values.
E is each independently an oxygen atom or a selenium atom, and can, for example, replace sulfur in the core described below.
L is each independently an anionic ligand having an organic group containing a carbon atom, the total number of carbon atoms of the organic group in each ligand is 14 or more, and each ligand may be the same or , may be different.
Each A is independently an anion other than L.
Q is each independently a neutral compound that donates electrons, and exists to fill empty coordination on the trinuclear molybdenum compound.

Here, in the lubricating oil composition of the present embodiment, from the viewpoint of reducing the coefficient of friction while ensuring high-temperature cleanliness of the lubricating oil composition, Mo atoms (Mo _C2 ) derived from molybdenum dithiocarbamate (C2) and The content ratio [Mo _C2 /Mo _C1 ] of the basic nitrogen compound to the molybdenum atom (Mo _C1 ) derived from the oxymolybdenum complex (C1) is preferably less than 1.0, more preferably 0. less than 5, more preferably less than 0.1, even more preferably less than 0.05, even more preferably less than 0.01.

[Physical property values of lubricating oil composition]
<Kinematic viscosity and viscosity index>
The 40°C kinematic viscosity of the lubricating oil composition of the present embodiment is preferably 5.0 mm ² /s or more and 150.0 mm ² /s or less, more preferably 10.0 mm ² /s or more and 100.0 mm ² /s or less, More preferably, the speed is 30.0 mm ² /s or more and 60.0 mm ² /s or less. When the kinematic viscosity at 40° C. is within the above range, fuel efficiency can be easily ensured.
The 100°C kinematic viscosity of the lubricating oil composition of this embodiment is preferably 4.0 mm ² /s or more, more preferably 5.0 mm ² /s or more, even more preferably 6.1 mm ² /s or more, and 6.9 mm ² /s or more is even more preferable, and 6.9 mm ² /s or more is even more preferable. Further, the 100°C kinematic viscosity of the lubricating oil composition of the present embodiment is preferably less than 22.0 mm ² /s, more preferably less than 20.0 mm ² /s, even more preferably less than 16.3 mm ² /s, and 12 Even more preferably less than .5 mm ² /s, even more preferably less than 9.3 mm ² /s, even more preferably less than 8.2 mm ² /s. When the kinematic viscosity at 100° C. is 4.0 mm ² /s or more, wear resistance can be easily ensured. Moreover, when the kinematic viscosity at 100° C. is low, it is easy to ensure fuel efficiency.
The viscosity index of the lubricating oil composition of this embodiment is preferably 80 or more, more preferably 85 or more, even more preferably 90 or more, and even more preferably 95 or more. When the viscosity index is 80 or more, the change in viscosity due to temperature becomes small.
The 40° C. kinematic viscosity, the 100° C. kinematic viscosity, and the viscosity index can be measured or calculated using, for example, a glass capillary viscometer in accordance with JIS K 2283:2000.

<Molybdenum atom content>
The content of molybdenum atoms in the lubricating oil composition of the present embodiment is preferably 0.025% by mass or more, more preferably 0.030% by mass, based on the total amount of the lubricating oil composition, from the viewpoint of easily reducing the coefficient of friction. The content is at least 0.035% by mass, more preferably at least 0.035% by mass, even more preferably at least 0.040% by mass.
Further, the upper limit of the molybdenum atom content is usually 0.200% by mass or less.
Note that the content of molybdenum atoms can be measured in accordance with JPI-5S-38-03.

<Calcium atom content>
The content of calcium atoms derived from the calcium-based detergent (D) in the lubricating oil composition of the present embodiment is determined from the viewpoint of achieving good high-temperature detergency and low sulfated ash content. Based on the total amount, preferably 0.020% by mass to 0.070% by mass, more preferably 0.025% by mass to 0.065% by mass, even more preferably 0.030% by mass to 0.060% by mass, and even more Preferably it is 0.035% by mass to 0.055% by mass.
Note that the content of calcium atoms can be measured in accordance with JPI-5S-38-03.

<Content of phosphorus atoms>
The content of phosphorus atoms in the lubricating oil composition of the present embodiment is 0.020% by mass or more and 0.040% by mass or less, based on the total amount of the lubricating oil composition.
If the content of phosphorus atoms is less than 0.020% by mass, generation of LSPI may not be suppressed. Moreover, if it exceeds 0.040% by mass, the amount of phosphorus atoms emitted increases and the exhaust gas purification catalyst may be poisoned.
Here, the content of phosphorus atoms in the lubricating oil composition is preferably 0.0000% based on the total amount of the lubricating oil composition, from the viewpoint of easily suppressing the generation of LSPI while reducing the amount of phosphorus atom discharged. 0.021 mass% or more and 0.036 mass% or less, more preferably 0.022 mass% or more and 0.032 mass% or less, and even more preferably 0.022 mass% or more and 0.030 mass% or less.
Note that the content of phosphorus atoms can be measured in accordance with JPI-5S-38-03.

<Content of zinc atoms>
The content of zinc atoms in the lubricating oil composition of the present embodiment is preferably 0.020% by mass to 0.040% by mass based on the total amount of the lubricating oil composition from the viewpoint of improving wear resistance. , more preferably 0.022% by mass to 0.036% by mass, still more preferably 0.024% by mass to 0.032% by mass.
Note that the content of zinc atoms can be measured in accordance with JPI-5S-38-03.

<Sulfur atom content>
The content of sulfur atoms in the lubricating oil composition of this embodiment is preferably 0.10% by mass or more and 0.25% by mass or less, and 0.16% by mass or more and 0.23% by mass, based on the total amount of the lubricating oil composition. It is more preferably at most 0.15% by mass and at most 0.21% by mass.
The content of sulfur atoms can be measured according to ASTM D2622.

<Boron atom content>
The boron atom content in the lubricating oil composition of this embodiment is preferably 0.030% by mass or more and 0.050% by mass or less, and 0.034% by mass or more and 0.045% by mass, based on the total amount of the lubricating oil composition. It is more preferably at most 0.036% by mass and at most 0.043% by mass.
The boron atom content can be measured in accordance with JPI-5S-38-03.

<Nitrogen atom content>
The content of nitrogen atoms in the lubricating oil composition of the present embodiment is preferably 0.150% by mass or more and 0.280% by mass or less, and 0.180% by mass or more and 0.250% by mass, based on the total amount of the lubricating oil composition. It is more preferably at most 0.200% by mass and at most 0.230% by mass.
The nitrogen atom content can be measured in accordance with JIS K 2609:1998.

<Sulfated ash>
The lubricating oil composition of this embodiment has a sulfated ash content of 0.30% by mass or less. The lubricating oil composition of this embodiment has good high-temperature detergency even with such a low sulfated ash content.
In the lubricating oil composition of this embodiment, the sulfated ash content is preferably 0.29% by mass or less, more preferably 0.28% by mass or less, and still more preferably 0.27% by mass or less.
Moreover, in the lubricating oil composition of this embodiment, the sulfated ash content is usually 0.01% by mass or more.

<LSPI inhibitory property>
The LSPI suppressing property of the lubricating oil composition of the present embodiment can be evaluated using, for example, a 2.0L inline four-cylinder engine manufactured by GM (trade name: Ecotec engine). Specifically, it can be evaluated by the method described in Examples described later. The total number of occurrences of LSPI in the method described in Examples described later is preferably 0 times.

<Base number, base number maintenance rate>
The lubricating oil composition of the present embodiment preferably has a base number maintenance rate of 0.20 or more, preferably 0.24 or more, and more preferably 0.35 or more, from the viewpoint of maintaining the base number at a certain level or more. .
The "base number" of the calcium-based detergent (D) in the lubricating oil composition of this embodiment can be measured by the perchloric acid method in accordance with JIS K 2501:2003.
The "base number maintenance rate" of the calcium-based detergent (D) of the lubricating oil composition of the present embodiment is calculated by dividing the base number after the NO _X injection test by the initial value of the base number.

<High temperature cleanliness>
The high-temperature cleanliness of the lubricating oil composition of the present embodiment can be determined by, for example, degrading the lubricating oil composition by blowing _NO It can be evaluated by This evaluation result can also be said to reflect the ability of the lubricating oil composition to maintain high-temperature cleanliness.
Specifically, it can be evaluated by the method described in Examples described later. Of the hot tube test scores of 0 to 10 in the method described in the Examples below, 2.5 or higher is preferable, and 3.0 or higher is more preferable.

<Friction coefficient>
The friction coefficient of the lubricating oil composition of this embodiment can be evaluated using, for example, an SRV tester (manufactured by Optimol). Specifically, it can be evaluated by the method described in Examples described later. The friction coefficient in the method described in the Examples below is preferably 0.13 or less, more preferably 0.12 or less.

[Applications of lubricating oil composition]
The lubricating oil composition of the present embodiment can suppress the generation of LSPI while having a low sulfated ash content and a low phosphorus content, and can also reduce the coefficient of friction while providing good high-temperature cleanliness. I can do it.
Therefore, the lubricating oil composition of this embodiment is preferably used for an internal combustion engine, more preferably used for an internal combustion engine equipped with an exhaust gas treatment device including a gasoline particulate filter (GPF), and is used for supercharging. It is more preferable to use it in a direct-injection internal combustion engine equipped with an engine. The internal combustion engine is preferably a gasoline engine, and more preferably a direct injection gasoline engine equipped with a supercharger.

[Method for producing lubricating oil composition]
In this embodiment, base oil (A), an aromatic carboxylic acid ester derivative (B1) represented by the following general formula (I), and an aromatic carboxylic acid ester derivative (B1) represented by the following general formula (II) ( One or more aromatic carboxylic acid ester derivatives (B) selected from B2), an oxymolybdenum complex of a basic nitrogen compound (C1), and a calcium-based detergent (D1) having a base value of 200 mgKOH/g or more. A method for producing a lubricating oil composition, comprising the step of mixing a calcium-based detergent (D) containing

[In the general formula (I), x and y are integers satisfying 1≦x≦3 and 1≦y≦3, respectively. R ¹ and R ² each independently represent an alkyl group having 9 to 20 carbon atoms. When x≧2, a plurality of R ¹ 's may be the same or different. When y≧2, a plurality of R ² may be the same or different. ]

[In the general formula (II), m, n, о, and p are respectively 1≦m≦2, 0≦n≦2, 2≦(m+n)≦4, 1≦о≦3, 1≦p≦ It is an integer that satisfies 3. R ³ and R ⁴ each independently represent an alkyl group having 9 to 20 carbon atoms. When о≧2, a plurality of R ³ 's may be the same or different. When p≧2, the plurality of R ^4s may be the same or different. ]
The amount of the aromatic carboxylic acid ester derivative (B) is 1.5% by mass or more based on the total amount of the lubricating oil composition,
The amount of molybdenum atoms derived from the oxymolybdenum complex (C1) of the basic nitrogen compound is 0.025% by mass or more based on the total amount of the lubricating oil composition,
The amount of calcium atoms derived from the calcium-based detergent (D) is 0.020% by mass or more and less than 0.080% by mass,
The sulfated ash content is 0.3% by mass or less,
Provided is a method for producing a lubricating oil composition, wherein the blending amount of phosphorus atoms is 0.020% by mass or more and 0.040% by mass or less, based on the total amount of the lubricating oil composition.

There are no particular restrictions on the method of mixing the above components, but for example, the base oil (A), the aromatic carboxylic acid ester derivative (B), the oxymolybdenum complex (C1) of a basic nitrogen compound, and the base oil (A) are mixed together. Examples include a step of adding and mixing a calcium-based detergent (D) containing a calcium-based detergent (D1) having a value of 200 mgKOH/g or more.
Moreover, the manufacturing method can further include the step of adding one or more selected from the other lubricating oil additives and other components described above.
Each component may be added in the form of a solution (dispersion) by adding diluting oil or the like. Moreover, after each component is added, it is preferable to include a step of stirring and uniformly dispersing it by a known method.

Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to these examples in any way. In addition, various properties of each component used in Examples and Comparative Examples and the obtained lubricating oil composition were measured by the following methods. These results are shown in Tables 1 to 3.

[Kinematic viscosity at 40°C, kinematic viscosity at 100°C, viscosity index]
It was measured and calculated using a glass capillary viscometer in accordance with JIS K2283:2000.

[Content of molybdenum atoms, calcium atoms, phosphorus atoms, zinc atoms, and boron atoms]
The contents of molybdenum atoms, calcium atoms, phosphorus atoms, zinc atoms, and boron atoms were measured in accordance with JPI-5S-38-03.

[Sulfur atom content]
The content of sulfur atoms was measured according to ASTM D2622.

[Nitrogen atom content]
The nitrogen atom content was measured in accordance with JIS K 2609:1998.

[Sulfated ash]
The sulfated ash content of the lubricating oil composition was measured in accordance with JIS K2272:1998.

[Base number]
The base number was measured by the perchloric acid method in accordance with JIS K 2501:2003.

[Examples 1 to 5 and Comparative Examples 1 to 14]
Each component shown below was added in the content shown in Tables 1 to 3 and thoroughly mixed to obtain a lubricating oil composition.
Details of each component used in Examples 1 to 5 and Comparative Examples 1 to 14 are as shown below.

<Base oil (A)>
100N mineral oil (classification in API base oil category: Group III, kinematic viscosity at 40°C: 20.0 mm ² /s, kinematic viscosity at 100°C: 4.2 mm ² /s, viscosity index: 123)

<Ester derivative>
- Aromatic carboxylic acid ester derivative (B): n-dodecylsalicylic acid-dodecyl phenyl ester. It is an aromatic carboxylic acid ester derivative (B1) represented by the above general formula (I), where x=1, y=1, R ¹ is an n-dodecyl group, and R ² is a dodecyl group.
・Boric acid ester (B'): Borated glycerol monooleate

<Molybdenum compound (C)>
- Oxymolybdenum complex of basic nitrogen compound (C1): Oxymolybdenum complex of succinimide (sulfur content, Mo: 5.5% by mass, S: 0.2% by mass, N: 1.6% by mass, base number : 10mgKOH/g, product name "OLOA17502", manufactured by Chevron Japan Co., Ltd.The base number of the oxymolybdenum complex (C1) was measured by the perchloric acid method in accordance with JIS K 2501:2003.)
・Dinuclear MoDTC (C2-1) (Mo: 10.0% by mass, S: 11.5% by mass)
・Trinuclear MoDTC (C2-3) (Mo: 5.5% by mass, S: 9.9% by mass)

<Calcium-based cleaning agent (D)>
・Calcium-based detergent (D1-1): Overbased calcium sulfonate (base number: 421 mgKOH/g, calcium atom content: 15.8% by mass)
・Calcium-based detergent (D1-2): Overbased calcium salicylate (base number: 221 mgKOH/g, calcium atom content: 7.9% by mass)
・Calcium-based detergent (D2): Neutral calcium sulfonate (base number: 21 mgKOH/g, calcium atom content: 2.4% by mass)

<ZnDTP(E)>
・ZnDTP (E1): ZnDTP having a primary alkyl group
・ZnDTP (E2): ZnDTP having a secondary alkyl group

<Additives for other lubricating oils>
Viscosity index improvers, pour point depressants, phenolic antioxidants, amine antioxidants, boron-free succinimides, boron-containing succinimides, metal deactivators, antifoaming agents, etc.

Moreover, the following evaluations were performed for each of the obtained lubricating oil compositions.

[Evaluation of LSPI inhibitory property]
A 2.0L inline 4-cylinder engine manufactured by GM (trade name: Ecotec engine) was used. The test conditions were based on the GMW17244 test method, and the evaluation was conducted under low load conditions (after warm-up operation (rotation speed: 2,000 rpm, torque: 100 Nm, net average effective pressure: 6 bar, operating time: 30 minutes). Rotation speed: 2,000 rpm, Torque: 32 Nm, Net average effective pressure: 2 bar, Operating time: 5 minutes) and High load condition operation (Rotation speed: 2,000 rpm, Torque: 350 Nm, Net average effective pressure: 22 bar, Operation time: 15 minutes) was repeated nine times each, and the total number of LSPI occurrences during operation under high load conditions was measured. As for the evaluation of LSPI suppressing properties, if the evaluation result was "A" according to the following evaluation criteria, it was evaluated that the lubricating oil composition had excellent LSPI suppressing properties. Note that LSPI was defined as occurring when the maximum combustion pressure was 30% or more higher than the average normal value and when the crank angle at the start of combustion was 5 degrees or more earlier than the normal value.
-Evaluation criteria for LSPI suppression-
A: The total number of occurrences of the LSPI is 0. B: The total number of occurrences of the LSPI is 1 or more.

[Evaluation of maintenance of high temperature cleanliness]
First, the base number (initial value) of the obtained lubricating oil composition was measured by the perchloric acid method according to JIS K 2501:2003.
Next, the oil temperature was set to 150° C., and _NOx gas at a concentration of 4,000 volume ppm was blown into the lubricating oil composition for 72 hours to degrade the lubricating oil composition. (With this deterioration treatment, the lubricating oil composition corresponds to the state after driving approximately 16,000 km.)
A hot tube test was conducted on the deteriorated lubricating oil composition at a temperature of 260°C. In addition, the base number (after the _NOx injection test) of the obtained lubricating oil composition was measured again by the perchloric acid method according to JIS K 2501:2003.
Furthermore, the base number maintenance rate was calculated by dividing the base number after the NO _X injection test by the initial value of the base number.
A lubricating oil composition with a hot tube test score of 2.5 or higher on a scale of 0 to 10 was evaluated to maintain high-temperature cleanliness for a long period of time.
Moreover, the sample after the hot tube test was visually observed, and if the evaluation result was "A" according to the following evaluation criteria, it was evaluated that the lubricating oil composition was excellent in maintaining high-temperature cleanliness.
-Evaluation criteria for precipitation in hot tube test-
A: White precipitation did not occur.
B: White precipitation occurred.

[Evaluation of friction coefficient reduction effect]
Based on ASTM D5706, the coefficient of friction when using the prepared lubricating oil composition was measured using an SRV tester (manufactured by Optimol) under the following conditions. In addition, the average value of the friction coefficient for 10 minutes from 20 minutes after the start of the test to the end of the test was taken as the friction coefficient. When the friction coefficient was 0.13 or less, it was evaluated that the lubricating oil composition was excellent in the effect of reducing the friction coefficient.
・Ball: AISI52100
・Disk: AISI52100
・Vibration frequency: 30Hz
・Amplitude: 3.0mm
・Load: 400N
・Temperature: 120℃
・Test time: 30 minutes

The evaluation results are shown in Tables 1 to 3.
In Tables 1 to 3, the content of molybdenum atoms in the lubricating oil composition is a value reflecting the content of molybdenum atoms derived from the molybdenum compound (C).
Furthermore, in Tables 1 to 3, the content of calcium atoms in the lubricating oil composition is a value that reflects the content of calcium atoms derived from the calcium-based detergent (D).
In addition, in Table 1, in Example 4, the calcium atom content derived from the calcium-based detergent (D1-1) was 0.026% by mass, and the calcium atom content derived from the calcium-based detergent (D2) was 0. It is .024% by mass.
Furthermore, in Tables 1 to 3, the content of phosphorus atoms in the lubricating oil composition is a value that reflects the content of phosphorus atoms derived from ZnDTP(E).
Furthermore, in Tables 1 to 3, the content of zinc atoms in the lubricating oil composition is a value that reflects the content of zinc atoms derived from ZnDTP(E).

The lubricating oil compositions of Examples 1 to 5, which satisfy all the requirements of the present invention, all exhibited excellent LSPI suppression properties, high-temperature cleanliness, and friction coefficient reduction effects.
On the other hand, in Comparative Examples 1 and 2 that do not contain the aromatic carboxylic acid ester derivative (B), and the content of the aromatic carboxylic acid ester derivative (B) is 1.5% by mass or more based on the total amount of the lubricating oil composition. Comparative Example 3, which did not meet the regulations, had poor results in the hot tube test, resulting in poor high-temperature cleanliness. In addition, in Comparative Example 4 containing boric acid ester (B') instead of aromatic carboxylic acid ester derivative (B), white precipitation occurred in the hot tube test, resulting in poor high-temperature cleanliness. .
Comparative Example 5 does not contain the basic nitrogen compound oxymolybdenum complex (C1) as the molybdenum compound (C), and the content of molybdenum atoms derived from the oxymolybdenum complex (C1) is 0 based on the total amount of the lubricating oil composition. Comparative Examples 5 to 8, which did not meet the .025 mass % regulation, had high friction coefficients and poor friction coefficient reduction effects. In addition, Comparative Examples 9 to 10 containing 2-nuclear MoDTC (C2-1) instead of the basic nitrogen compound oxymolybdenum complex (C1), and Comparative Example 11 containing 3-nuclear MoDTC (C2-3) The results of the hot tube test were poor, and the high temperature cleanliness was poor.
As a calcium-based detergent (D), a calcium-based detergent (D2) whose base number is less than 200 mgKOH/g without containing a calcium-based detergent (D1) whose base number is 200 mgKOH/g or more is 0.050 Comparative Example 12 containing % by mass had poor results in the hot tube test, resulting in poor high-temperature cleanliness.
In Comparative Examples 13 and 14, in which the content of phosphorus atoms was less than 0.020% by mass based on the total amount of the lubricating oil composition, LSPI was generated and the LSPI suppressing properties were poor.

Claims (7)

selected from base oil (A), aromatic carboxylic acid ester derivative (B1) represented by the following general formula (I), and aromatic carboxylic acid ester derivative (B2) represented by the following general formula (II) A calcium-based detergent containing one or more aromatic carboxylic acid ester derivatives (B), an oxymolybdenum complex of a basic nitrogen compound (C1), and a calcium-based detergent (D1) having a base value of 200 mgKOH/g or more (D) A lubricating oil composition containing

[In the general formula (I), x and y are integers satisfying 1≦x≦3 and 1≦y≦3, respectively. R ¹ and R ² each independently represent an alkyl group having 9 to 20 carbon atoms. When x≧2, a plurality of R ¹ 's may be the same or different. When y≧2, a plurality of R ² may be the same or different. ]

[In the general formula (II), m, n, о, and p are respectively 1≦m≦2, 0≦n≦2, 2≦(m+n)≦4, 1≦о≦3, 1≦p≦ It is an integer that satisfies 3. R ³ and R ⁴ each independently represent an alkyl group having 9 to 20 carbon atoms. When о≧2, a plurality of R ³ 's may be the same or different. When p≧2, the plurality of R ^4s may be the same or different. ]
The content of the aromatic carboxylic acid ester derivative (B) is 1.5% by mass or more based on the total amount of the lubricating oil composition,
The content of molybdenum atoms derived from the oxymolybdenum complex (C1) of the basic nitrogen compound is 0.025% by mass or more based on the total amount of the lubricating oil composition,
The content of calcium atoms derived from the calcium-based detergent (D) is 0.020% by mass or more and less than 0.080% by mass, based on the total amount of the lubricating oil composition,
The sulfated ash content is 0.3% by mass or less,
The content of phosphorus atoms is 0.020% by mass or more and 0.040% by mass or less, based on the total amount of the lubricating oil composition ,
A lubricating oil composition used in direct injection internal combustion engines equipped with a gasoline particulate filter (GPF) and a supercharger . The lubricant according to claim 1, wherein the content of calcium atoms derived from the calcium-based detergent (D1) is 0.020% by mass or more and less than 0.080% by mass, based on the total amount of the lubricating oil composition. oil composition. 2. The content of calcium atoms derived from the calcium-based detergent (D2) having a base value of less than 200 mgKOH/g is less than 0.025% by mass based on the total amount of the lubricating oil composition. The lubricating oil composition described in . The content ratio [Ca _D2 /Ca _D1 ] of the calcium atoms (Ca _D2 ) derived from the calcium-based detergent (D2) and the calcium atoms (Ca _D1 ) derived from the calcium-based detergent (D1) is expressed as a mass ratio. 4. The lubricating oil composition of claim 3, wherein the lubricating oil composition is less than 0.31. According to any one of claims 1 to 4, the content of Mo atoms derived from molybdenum dithiocarbamate (MoDTC) (C2) is less than 0.020% by mass based on the total amount of the lubricating oil composition. lubricating oil composition. The content ratio of the Mo atom (Mo C2 ) derived from the molybdenum dithiocarbamate (MoDTC) ( _C2 ) and the molybdenum atom (Mo C1 ) derived from the oxymolybdenum complex ( _C1 ) of the basic nitrogen compound [Mo _C2 / The lubricating oil composition according to claim 5, wherein the mass ratio of Mo _C1 is less than 1.0. The lubricating oil composition according to any one of claims 1 to 6, further comprising zinc dithiophosphate (ZnDTP) (E).