DE112017000967T5 - Lubricating oil composition and process for producing a lubricant oil composition - Google Patents

Abstract

A lubricant oil composition comprising a base oil (A); a molybdenum dithiophosphate (B1) in an amount of 400 mass ppm or more in terms of molybdenum atom; an organic metal-based cleaning agent (C1) having a metal atom selected from an alkali metal atom and an alkaline earth metal atom in an amount of 1400 mass ppm or less in terms of a metal atom; and an hindered amine antioxidant (D1) in an amount of 900 mass ppm or more in terms of nitrogen atom, wherein a sulfated ash content is 0.70 mass% or less. The lubricant oil composition may be one in which the detergency, the abrasion resistance and the friction-reducing effect are improved with a good balance while the ash content is reduced.

Description

Technical area

This invention relates to a lubricating oil composition and a process for producing the lubricating oil composition.

background

In recent years, regulation on a global scale is becoming increasingly stringent, and the conditions relating to automobiles are becoming more stringent in terms of fuel consumption regulations, exhaust gas regulations, etc. In particular, improvement in fuel consumption of vehicles such as automobiles is a big issue. As means for solving this issue, low friction properties of a lubricant oil composition for an internal combustion engine used for vehicles are required.

For obtaining a lubricant oil composition having a reduced friction coefficient, a friction modifier such as an organic molybdenum compound is generally used.

For example, PTL 1 discloses a machine oil composition obtained by mixing a base oil with certain amounts of an organic molybdenum compound, a boron-based succinimide, and an alkaline earth metal salt of salicylic acid.

PTL 1 describes that said engine oil composition is able to take effect to reduce the friction loss of a machine for a long period of time.

List of pamphlets

patent literature

PTL 1: JP 5-163497 A

Summary of the invention

Technical problem

In order to control the air pollution, it is now necessary to reduce nitrogen oxides (NOx) or particulate matter (particulates) in the exhaust gas of a diesel engine. As countermeasures for this, development of an exhaust post-processing plant using a three-way catalyst, an oxidation catalyst, a diesel particulate filter, etc. is proceeding.

In addition, in recent years, in order to improve the fuel consumption performance, the development of a direct injection gasoline engine mounted with a supercharger such as a turbocharger has been developed. Like the case of a diesel engine, soot such as a particulate matter (PM) contained in an exhaust gas is generated due to the direct injection of a gasoline engine. As a result, even in the gasoline engine, it is necessary to install an exhaust gas post-processing equipment such as a gasoline particle filter.

When a lubricant oil composition for an internal combustion engine having a metal-based detergent is used for an engine connected to such an exhaust gas post-processing equipment, there is a fear that a metal component derived from a metal-based detergent, etc., is accumulated in the interior of the film in the exhaust gas post-processing plant, causing the filter clogged or the catalytic activity is reduced.

In order to avoid the above problem, it is necessary to reduce the ash content of the lubricant oil composition. The reduction in the content of the metal-based detergent causes a decrease in the base number, whereby deterioration of the cleaning effect may be caused and burning (a phenomenon in which the lubricant oil composition is carbonized and denatured to form a carbide) may also be generated.

In addition, according to the research conducted by these inventors, in the lubricating oil composition for an internal combustion engine containing a lot of metal-based detergents, the friction coefficient with respect to a motor part may increase, thereby possibly lowering the friction-reducing Effect is caused.

Accordingly, a lubricant oil composition is required for an internal combustion engine with a low ash content, while both the cleaning effect and the friction-reducing effect are good.

The engine oil composition described in PTL 1 is originally one which does not have a low ash content. In addition, in PTL 1, the deterioration of the detergency after reduction of the ash content of the disclosed engine oil composition is not considered.

Furthermore, a lubricant oil composition used for vehicles, etc., must also have abrasion resistance, while a sliding mechanism provided with a piston ring and a liner is smoothly lubricated.

In general, an anti-abrasion agent such as zinc dithiophosphate (ZnDTP) is used to obtain a lubricant oil composition having good abrasion resistance. The anti-abrasion agent forms a film on the metal surface by adsorption on the metal surface of the sliding member, reaction with a metal atom on the surface, generation of a polymer on the metal surface, etc., thereby contributing to an improvement in abrasion resistance.

As the content of ZnDTP in the lubricant oil composition increases, the friction reducing effect of the lubricant oil composition tends to be lowered.

Accordingly, a lubricant oil composition which is capable of maintaining a good friction-reducing effect while improving the abrasion resistance is also required.

In view of the above circumstances, this invention has been carried out, and an object thereof is to provide a lubricating oil composition wherein the detergency, the abrasion resistance and the friction reducing effect are well balanced while the ash content is reduced; and to provide a method for producing the lubricant oil composition.

the solution of the problem

These inventors have found that the above problem can be solved by a lubricant oil composition in which the sulfated ash content is controlled to a certain value or less, the lubricant oil composition being a base oil as well as molybdenum dithiophosphate, a metal-based organic detergent and Furthermore, the content of these three components is set to specific ranges, whereby this invention has been completed.

1. [1] Schmiermittelöl-Zusammensetzung, enthaltend:
   • ein Grundöl (A);
   • ein Molybdändithiophosphat (B1) in einer Menge von 400 Massen-ppm oder mehr, ausgedrückt als Molybdänatom;
   • ein organisches Reinigungsmittel auf Metallbasis (C1), das ein Metallatom enthält, ausgewählt aus einem Alkalimetallatom und einem Erdalkalimetallatom, in einer Menge von 1400 Massen-ppm oder weniger, ausgedrückt als Metallatom; und
   • ein Antioxidans (D1) auf gehinderter Aminbasis in einer Menge von 900 Massen-ppm oder mehr, ausgedrückt als Stickstoffatom,
   • mit einem sulfatierten Aschegehalt von 0,70 Massen-% oder weniger.
2. [2] Verfahren zur Verwendung einer Schmiermittelöl-Zusammensetzung unter Verwendung der Schmiermittelöl-Zusammensetzung gemäß obigem Aspekt [1] für einen internen Verbrennungsmotor, der mit einer Abgas-Nachverarbeitungsvorrichtung versehen ist.
3. [3] Verfahren zur Erzeugung einer Schmiermittelöl-Zusammensetzung, umfassend den folgenden Schritt (I):
   • (I): einen Schritt unter Vermischung
   • eines Grundöls (A);
   • eines Molybdändithiophsphats (B1) in einer Menge von 400 Massen-ppm oder mehr, ausgedrückt als Molybdänatom;
   • eines organischen Reinigungsmittels (C1) auf Metallbasis, enthaltend ein Metallatom, ausgewählt aus einem Alkalimetallatom und einem Erdalkalimetallatom in einer Menge von 1400 Massen-ppm oder weniger, ausgedrückt als Metallatom; und
   • eines Antioxidans (D1) auf gehinderter Aminbasis in einer Menge von 900 Massen-ppm oder mehr, ausgedrückt als Stickstoffatom,
   • unter Erhalt einer Schmiermittelöl-Zusammensetzung mit einem sulfatierten Aschegehalt von 0,70 Massen-% oder weniger.

Specifically, this invention provides the following aspects [1] to [3].

1. [1] Lubricating oil composition containing:
   • a base oil (A);
   • a molybdenum dithiophosphate (B1) in an amount of 400 mass ppm or more in terms of molybdenum atom;
   • an organic metal-based cleaner (C1) containing a metal atom selected from an alkali metal atom and an alkaline earth metal atom in an amount of 1400 mass ppm or less in terms of a metal atom; and
   • an hindered amine antioxidant (D1) in an amount of 900 mass ppm or more in terms of nitrogen atom,
   • with a sulfated ash content of 0.70 mass% or less.
2. [2] A method of using a lubricant oil composition using the lubricant oil composition according to the above aspect [1] for an internal combustion engine provided with an exhaust gas post-processing device.
3. [3] A process for producing a lubricant oil composition, comprising the following step (I):
   • (I): a step under mixing
   • a base oil (A);
   • a molybdenum dithiophosphate (B1) in an amount of 400 mass ppm or more in terms of molybdenum atom;
   • an organic cleaning agent (C1) based on metal, containing a metal atom selected from an alkali metal atom and an alkaline earth metal atom in an amount of 1400 mass ppm or less in terms of a metal atom; and
   • hindered amine antioxidant (D1) in an amount of 900 mass ppm or more in terms of nitrogen atom,
   • to obtain a lubricant oil composition having a sulfated ash content of 0.70 mass% or less.

Advantageous Effects of the Invention

The lubricating oil composition of this invention is excellent in detergency, abrasion resistance and friction-reduced effect while reducing the ash content.

Description of exemplary embodiments

In this invention, the term "alkali metal atom" refers to a lithium atom (Li), sodium atom (Na), potassium atom (K), rubidium atom (Rb), cesium atom (Cs), and fromerate (Fr).

In addition, the term "alkaline earth metal atom" refers to a beryllium atom (Be), magnesium atom (Mg), calcium atom (Ca), strontium atom (Sr) and barium atom (Ba).

• • Molybdänatom (Mo), Calciumatom (Ca), Boratom (B), Kaliumatom (K), Zinkatom (Zn) und Phosphoratom (P): gemessen entsprechend JPI-5S-38-92
• • Schwefelatom (S): gemessen entsprechend JIS K2541-6
• • Stickstoffatom (N): gemessen entsprechend JIS K2609

In this specification, the content of each atom means a value measured according to the following standards.

• Molybdenum atom (Mo), calcium atom (Ca), boron atom (B), potassium atom (K), zinc atom (Zn) and phosphorus atom (P): measured in accordance with JPI-5S-38-92
• Sulfur atom (S): measured according to JIS K2541-6
• Nitrogen atom (N): measured according to JIS K2609

[Lubricant oil composition]

The lubricant oil composition of the present invention contains a base oil (A), a molybdenum dithiophosphate (MoDTP) (B1), a metal-based organic detergent (C1), and a hindered amine-based antioxidant (D1).

The lubricant oil composition of this invention is a low ash content lubricant oil composition wherein the sulfated ash content is set to 0.70 mass% or less. The sulfated ash content can be made small by reducing the content of the metal-based organic detergent (C1) or a metal-based compound such as ZnDTP in the lubricant oil composition.

The lubricant oil composition of this invention is one having a low ash content, wherein the content of the metal-based organic detergent (C1) or the metal-based compound such as ZnDTP is reduced, and therefore the occurrence of a harmful effect such as clogging of the filter or reduction of the catalytic Activity can be prevented, even if it is used for example for an engine that is connected to an exhaust post-processing plant.

In a usual case, when the content of the metal-based organic detergent (C1) is lowered, the base number of the obtained lubricant oil composition is lowered, deterioration of the cleaning effect is caused, and generation of coking can also be inhibited.

In contrast, the lubricant oil composition of this invention contains an hindered amine antioxidant (D1) as an antioxidant, and therefore, even if the content of the organic metal-based cleaner (C1) is low, the cleaning effect can be well maintained and the generation of coking can be achieved also be prevented.

In addition, a lubricant oil composition which can give an excellent friction-reducing effect can be given by lowering the content of the metal-based organic detergent (C1) or metal-based compound such as ZnDTP and controlling the sulfated ash content to 0.70 mass%. % Or less.

However, in the lubricant oil composition of this invention, it becomes possible to obtain a greater improvement in the friction-reducing effect by not only decreasing the content of the metal-based organic detergent (Zn) or ZnDTP, and reducing the sulfated ash content to 0.70 mass%. % or less, but also containing the molybdenum dithiophosphate (B1) as a molybdenum-based compound.

In the lubricant oil composition containing the above-mentioned components and containing a reduced content of the metal-based compound, the abrasion resistance of the lubricant oil composition can be effectively improved by using the molybdenum dithiophosphate (B1) even if the content of ZnDTP is decreased becomes.

For, in the lubricant oil composition of this invention, the lubricant oil composition can become one in which the detergency, the abrasion resistance and the friction-reducing effect are improved with good balance by not only setting the sulfated ash content to 0.70 mass% or less but by commonly using the molybdenum dithiophosphate (B1), the metal-based organic detergent (C1), and the hindered amine-based antioxidant (D1) at the specified levels.

In view of this, the sulfated ash content of the lubricating oil composition of one embodiment in this invention is preferably 0.60 mass% or less, more preferably 0.55 mass% or less, still more preferably 0.50 mass% or less more preferably 0.40 mass% or less, and more preferably 0.38 mass% or less based on the total amount (100 mass%) of the lubricant oil composition.

Considering the contents of the components (B1) and (C1), the sulfated ash content of the lubricant oil composition of one embodiment in this invention is preferably 0.06 mass% or more, more preferably 0.10 mass% or more, even more preferably 0.15 mass% or more, more preferably 0.20 mass% or more, and particularly preferably 0.22 mass% or more based on the total amount (100 mass%) of the lubricant oil composition.

In this specification, the sulfated ash content means a value measured according to JIS K2272.

Although the lubricant oil composition of this invention contains the molybdenum dithiophosphate (B1) as the molybdenum-based compound (B), it may further contain a molybdenum dithiocarbamate (MoDTC) (B2).

Although the lubricant oil composition of this invention contains the metal-based organic detergent (C1) as the detergent (C), it preferably further contains an alkali metal borate (C2) and may contain an ashless detergent (C3).

Although the lubricant oil composition of this invention contains the hindered amine antioxidant (D1) as the antioxidant (D), it may further contain a different antioxidant (D2) than the component (D1).

The lubricant oil composition of one embodiment of this invention may further contain a zinc dithiophosphate (ZnDTP) (E1) as an antiwear agent (E).

The lubricant oil composition of one embodiment of this invention may contain other additives for the lubricant oil corresponding to the above-mentioned components, such as a friction modifier, viscosity index improver, extreme pressure agent, metal deactivator, pour point depressant, rust inhibitor and anti-foaming agent, within a range such that the effects of this invention are not impaired.

In the lubricant oil composition of one embodiment of this invention, a total blending amount of the component (A), the component (B1), the component (C1) and the component (D1) is preferably 70% by mass or more, more preferably 75% by mass. % or more, and more preferably 80% by mass or more, and is typically 100% by mass or less, more preferably 99.9% by mass or less, and even more preferably 99.0% by mass or less based on the total amount (100 mass%) of the lubricant oil composition.

In the lubricant oil composition of an embodiment in this invention, the total blending amount of the base oil (A), the molybdenum-based compound (B) containing the component (B1), the detergent (C) containing the component (C1) , an antioxidant (D) containing the component (D1) and the anti-abrasion agent (E) containing the component (E1), preferably 73% by mass or more, more preferably 77% by mass or more, and even more preferably Is 83 mass% or more, and is typically 100 mass% or less, more preferably 99.9 mass% or less, and even more preferably 99.0 mass% or less based on the total amount (100 mass%) of lubricating oil composition.

Each component contained in the lubricant oil composition of an embodiment in this invention will be described below.

<Base oil (A)>

The base oil (A) contained in the lubricant oil composition of an embodiment in this invention may be a mineral oil or a synthetic oil, and a mixed oil of a mineral oil and a synthetic oil may also be used.

Examples of the mineral oil include easily distilled portions obtained by conducting atmospheric distillation with a crude oil such as a paraffinic mineral oil, an intermediate-based mineral oil and a naphthenic mineral oil; Distillates obtained by carrying out distillation with the easily distilled substances under reduced pressure; Mineral oils which deasphalt from solvent treatment of the distillate one or more times, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrorefining, etc .; and mineral oils obtained by isomerizing a wax (GTL wax (gaseous to liquid wax)) obtained by the Fischer-Tropsch method or the like.

These mineral oils may be used alone or in combination of two or more thereof.

Among them, a mineral oil with which one or more treatments of solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrorefining, etc. has been carried out, and a mineral oil obtained by isomerizing a GTL wax as a mineral oil in one embodiment are preferred this invention is used; a mineral oil classified in Group 2 or Group 3 of the Synthesis Base Oil Classes of API (American Petroleum Institute), and a mineral oil obtained by isomerization of a GTL wax are more preferable; and a mineral oil classified into the aforementioned Group 3, and a mineral oil obtained by isomerization of a GTL wax are even more preferable.

Examples of the synthetic oil include a poly-α-olefin such as an α-olefin homopolymer or an α-olefin copolymer (eg, an α-olefin copolymer having a carbon number of 8 to 14 such as an ethylene-α-olefin copolymer) ; an isoparaffin; various esters such as a polyol ester and a diacid acid ester; various ethers, such as a polyphenyl ether; a polyalkylene glycol; alkyl benzene; alkylnaphthalene; and a synthetic oil obtained by isomerizing a wax (GTL wax) produced by the Fischer-Tropsch method or the like.

These synthetic oils may be used alone or in combination of two or more thereof.

Among them, preferred are one or more synthetic oils selected from a poly-α-olefin, various esters, and a polyalkylene glycol as a synthetic oil used in an embodiment of the invention, and a poly-α-olefin is more preferable.

A kinematic viscosity at 100 ° C of the base oil (A) is preferably 2.0 to 20.0 mm ² / s, more preferably 2.0 to 15.0 mm ² / s, still more preferably 2.0 to 7.0 mm ² / s and more preferably 2.0 to 5.0 mm ² / s.

When the kinematic viscosity at 100 ° C of the base oil (A) is 2.0 mm ² / s or more, an evaporation loss is small, and therefore, it is preferable. On the other hand, when the kinematic viscosity at 100 ° C of the base oil (A) is 20 mm ² / s or less, an energy loss caused due to a large resistance can be suppressed, and a gasoline consumption improving effect is obtained, and therefore this is preferred.

In view of not only suppressing a change in the viscosity caused by a temperature change, but also improving the fuel-saving properties, a viscosity index of the base oil (A) is preferably 80 or more, more preferably 100 or more and more more preferably 120 or more.

In the invention, the "kinematic viscosity at 100 ° C" and the "viscosity index" means values measured and calculated in accordance with JIS K2283.

When the base oil (A) is a mixed oil of two or more selected from a mineral oil and a synthetic oil, it is preferable that the kinematic viscosity and the viscosity index of the mixed oil fall within the above ranges.

In the lubricant oil composition of one embodiment of this invention, the content of the base oil (A) is preferably 60% by mass or more, more preferably 65% by mass or more, still more preferably 70% by mass or more and still more preferably 75% Mass% or more, and is preferably 99 mass% or less, more preferably 95 mass% or less based on the total amount (100 mass%) of the lubricant oil composition.

<Molybdenum dithiophosphate (B1)>

The lubricant oil composition of this invention contains the molybdenum dithiophosphate (MoDTP) (B1) as the molybdenum-based compound (B).

According to the research conducted by these inventors, in the low ash content lubricant oil composition wherein the content of the metal-based organic detergent (C1) is reduced, it has been found that the friction-reducing effect can be more improved MoDTP compared to the case where another molybdenum-based compound such as MoDTC alone is used.

It is conceivable that a film formed of the MoDTP-containing lubricant oil composition having a low ash content is solid as compared with a film formed using MoDTC.

In general, in order to improve the abrasion resistance, a case where a zinc dithiophosphate (ZnDTP) is used which is an antiwear agent is often found.

According to the studies of these inventors, in the low ash content lubricant oil composition, it has been found that when using MoDTP alone without using the antiabrasion agent such as ZnDTP, the effect of improving the abrasion resistance is large even in comparison with the use of only ZnDTP.

As mentioned above, when the content of ZnDTP in the lubricant oil composition is increased, there is a tendency that the friction-reducing effect of the lubricant oil composition is lowered.

For suppressing a lowering of the friction-reducing effect, when MoDTC, which is the friction modifier, is used in combination with ZnDTP, competitive adsorption to the metal surface of the engine part is generated, and formation of a film due to both components insufficient, and as a result, the abrasion resistance or the friction-reducing effect is sometimes deteriorated.

On the contrary, even when using MoDTP alone without using ZnDTP or the like, or when using MoDTP in combination with ZnDTP, the abrasion resistance and the friction-reducing effect can be improved with good balance by using MoDTP.

In the lubricant oil composition of this invention, in view of obtaining a lubricant oil composition which is improved in abrasion resistance and friction-reducing effect, the content of the component (B1) in terms of molybdenum atom is 400 mass ppm or more, preferably 500 ppm by mass or more, more preferably 600 ppm by mass or more, even more preferably 700 ppm by mass or more, further preferably 800 ppm by mass or more, and particularly preferably 900 ppm by mass or more based on the total amount ( 100% by mass) of the lubricant oil composition.

From the viewpoint of adjusting the sulfated ash content of the obtained lubricating oil composition to the above-mentioned range, the content of the component (B1) in terms of molybdenum atom is preferably 2000 ppm by mass or less, more preferably 1800 ppm by mass or less, even more preferably 1500 ppm by mass or less and more preferably 1300 ppm by mass or less based on the total amount (100% by mass) of the lubricant oil composition.

In the lubricant oil composition of an embodiment of this invention, the blending amount of the component (B1) can be controlled so that the content in terms of the molybdenum atom falls within the above range, but is preferably 0.40 to 2.60 mass%. more preferably 0.50 to 2.40 mass%, more preferably 0.50 to 2.00 mass%, even more preferably 0.50 to 1.80 mass% and particularly preferably 0.55 to 1, 60 mass% based on the total amount (100 mass%) of the lubricant oil composition.

As the molybdenum dithiophosphate (B1), a compound having the following general formula (b1-1) and a compound having the following general formula (b1-2) are preferable.

In the present invention, the molybdenum dithiophosphate (B1) may be used alone or in combination of two or more.

In the general formulas (b1-1) and (b1-2), R ¹ to R ^{4 are} each independently a hydrocarbon group and may be the same or different from each other.

X ¹ to X ⁸ are each independently an oxygen atom or a sulfur atom and may be the same or different from each other, provided that at least two of X ¹ to X ⁸ in the formula (b1-1) are a sulfur atom.

In one embodiment of this invention, in the general formula (b1-1), it is preferable that X ¹ and X ^{2 are} an oxygen atom and X ³ to X ^{8 are} a sulfur atom.

In the general formula (b1-2), it is preferable that X ¹ and X ^{2 are} an oxygen atom and X ³ and X ^{4 are} a sulfur atom.

In the general formula (b1-1) in view of the improvement of the solubility in the base oil (A) has a molar ratio of a sulfur atom to an oxygen atom [sulfur atom / oxygen atom] in X ¹ to X ⁸ is preferably 4.1 to 1.4 and more preferably 1/3 to 3/1.

In the general formula (b1-2), from the same viewpoint, a molar ratio of a sulfur atom to an oxygen atom [sulfur atom / oxygen atom] in X ¹ to X ^{4 is} preferably 1/3 to 3/1, and more preferably 1.5 / 2, 5 to 2.5 / 1.5.

The carbon number of the hydrocarbon group which can be selected as R ¹ to R ⁴ is preferably 1 to 20, more preferably 5 to 18, still more preferably 5 to 16, and still more preferably 5 to 12.

Specifically, examples of the hydrocarbon group which can be selected as R ¹ to R ⁴ include an alkyl group such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, Hexadecyl group, heptadecyl group and octadecyl group; an alkenyl group such as octenyl group, nonenyl group, decenyl group, undecenyl group, dodecenyl group, tridecenyl group, tetradecenyl group and pentadecenyl group; a cycloalkyl group such as cyclohexyl group, dimethylcyclohexyl group, ethylcyclohexyl group, methylcyclohexylmethyl group, cyclohexylethyl group, propylcyclohexyl group, butylcyclohexyl group and heptylcyclohexyl group; an aryl group such as phenyl group, naphthyl group, anthracenyl group, biphenyl group and terphenyl group; an alkylaryl group such as tolyl group, dimethylphenyl group, butylphenyl group, nonylphenyl group, methylbenzyl group and dimethylnaphthyl group; and an arylalkyl group such as phenylmethyl group, phenylethyl group and diphenylmethyl group.

<Molybdenum dithiocarbamate (B2)>

The lubricant oil composition of one embodiment of this invention may include as molybdenum-based compound (B) a molybdenum dithiocarbamate (MoDTC) (B2) together with the molybdenum dithiophosphate (MoDTP) (B1).

When MoDTC is used together with MoDTP without exclusive use, a lubricant oil composition excellent in abrasion resistance and friction reducing effect can be obtained.

In the lubricant oil composition of one embodiment of this invention, the content of the component (B2) in terms of molybdenum atom is preferably 0 to 1300 mass ppm, more preferably 0 to 800 mass ppm, even more preferably 0 to 600 mass ppm and more preferably 0 to 500 ppm by mass based on the total amount (100% by mass) of the lubricant oil composition.

In the lubricating oil composition of an embodiment of this invention, although the blending amount of the component (B2) can be controlled so that the content in terms of the molybdenum atom falls within the above-mentioned range, it is preferably 0 to 1.60 mass%. more preferably 0 to 1.00 mass%, more preferably 0 to 0.80 mass% and even more preferably 0 to 0.70 mass% based on the total amount (100 mass%) of the lubricant oil composition.

A ratio of the content of the component (B2) in terms of molybdenum atom is preferably 0 to 150 parts by mass, more preferably 0 to 100 parts by mass, still more preferably 0 to 80 parts by mass, and still more preferably 0 to 40 parts by mass based on 100 parts by mass of Total amount of component (B1) expressed as molybdenum atom.

Examples of the molybdenum dithiocarbamate (B2) include a binuclear molybdenum dithiocarbamate (B21) having two molybdenum atoms in a molecule thereof; and a trinuclear molybdenum dithiocarbamate (B22) having three molybdenum atoms in a molecule thereof.

According to the invention, the molybdenum dithiocarbamate (B2) can be used either alone or in combination of two or more.

In the lubricant oil composition of an embodiment in this invention, when the component (B21) and the component (B22) are contained, from the viewpoint of obtaining a lubricant oil composition excellent in abrasion resistance and friction-reducing effect, a ratio of the content of the components (B21) to the component (B22) [(B21) / (B22)] is preferably 0.1 / 1 to 5/1, more preferably 0.2 / 1 to 4/1, more preferably 0.3 / 1 to 3/1, and more preferably 0.4 / 1 to 2/1, in terms of mass ratio.

The ratio as the content of the component (B21) to the component (B22) [(B21) / (B22)] is preferably 0.1 / 1 to 5/1, more preferably 0.2 / 1 to 4/1, more preferably 0.3 / 1 to 3/1 and more preferably 0.4 / 1 to 2/1 in terms of the ratio in terms of molybdenum atom.

As the binuclear molybdenum dithiocarbamate (B21), a compound having the following general formula (b21-1) and a compound having the following general formula (b21-2) are preferable.

In the general formulas (b21-1) and (b21-2), R ¹¹ to R ^{14 are} each independently a hydrocarbon group and may be the same or different from each other.

X ¹¹ to X ¹⁸ are each independently an oxygen atom or a sulfur atom and may be the same or different from each other, provided that at least two of X ¹¹ to X ¹⁸ in the formula (b21-1) are a sulfur atom.

In one embodiment of this invention, it is preferred in the general formula (b21-1) that X ¹¹ and X ¹² is an oxygen atom and X ¹³ to X ¹⁸ is a sulfur atom.

In the general formula (b21-2), it is preferable that X ¹¹ to X ^{14 are} an oxygen atom.

In the general formula (b21-1), in view of improving the solubility in the base oil (A), a molar ratio of a sulfur atom to an oxygen atom [sulfur atom / oxygen atom] in X ¹¹ to X ^{18 is} preferably 1/4 to 4/1 and more preferably 1/3 to 3/1.

The carbon number of the hydrocarbon group which can be selected as R ¹¹ to R ¹⁴ is preferably 7 to 22, more preferably 7 to 18, still more preferably 7 to 14, and further more preferably 8 to 13.

As the specific hydrocarbon group which can be selected as R ¹¹ to R ¹⁴ in the general formulas (b21-1) and (b21-2), the same hydrocarbon groups as those represented as R ¹ to R ⁴ in the general formula (b1 1) or (b1-2) can be selected.

As the trinuclear molybdenum dithiocarbamate (B22), a compound having the following general formula (b22-1) is preferable. Mo ₃ S _k E _m L _n A _p Q _z (b22-1)

In the general formula (b22-1), k is an integer of 1 or more; m is an integer of 0 or more; and (k + m) is an integer from 4 to 10 and preferably an integer from 4 to 7. n is an integer from 1 to 4; and p is an integer of 0 or more. z is an integer of 0 to 5 inclusive of a non-stoichiometric value.

The groups E are each independently an oxygen atom or selenium atom, and for example, they are capable of substituting sulfur in a nucleus, as mentioned later.

The groups L are each independently an anionic ligand having a carbon atom-containing organic group; a total of the carbon atoms of the organic group in each ligand is 14 or more; and the respective ligands may be the same or different from each other.

The groups A are each independently an anion other than L.

The groups Q are each independently a compound capable of giving a neutral electron and exist for the purpose of obtaining a vacant coordination site on the trinuclear molybdenum compound.

A total of the carbon atoms of the organic group in the anionic ligand represented by L is preferably 14 to 50, more preferably 16 to 30, and still more preferably 18 to 24.

As L, a monoanionic ligand which is a monovalent anionic ligand is preferable, and specifically, ligands having the following general formulas (i) to (iv) are more preferable.

In the general formula (b22-1), the anionic ligand selected as L is preferably a ligand having the following general formula (iv).

In the general formula (b22-1), it is preferable that all anionic ligands selected as L are the same, and it is more preferable that all the anionic ligands selected as L be a ligand having the following general formula (iv) are.

In the general formulas (i) to (iv), X ³¹ to X ³⁷ and Y are each independently an oxygen atom or a sulfur atom and may be the same or different from each other.

In the general formulas (i) to (iv), R ³¹ to R ^{35 are} each independently an organic group and may be the same or different from each other.

The carbon number of each organic group which can be selected as R ³¹ , R ³² and R ³³ is preferably 14 to 50, more preferably 16 to 30 and even more preferably 18 to 24.

The total carbon number of the two organic groups which can be selected as R ³⁴ and R ³⁵ in the formula (iv) is preferably 14 to 50, more preferably 16 to 30 and still more preferably 18 to 24.

The carbon number of each organic group which can be selected as R ³⁴ and R ³⁵ is preferably 7 to 30, more preferably 7 to 20, and still more preferably 8 to 13.

Although the organic group of R ³⁴ and the organic group of R ^{35 may be the} same or different from each other, they are preferably different from each other. In addition, although the carbon number of the organic group of R ³⁴ and the carbon number of the organic group of R ³⁵ may be the same or different, they preferably differ from each other.

Examples of the organic group selected as R ³¹ to R ³⁵ include a hydrocarbon group such as an alkyl group, aryl group, substituted aryl group and an ether group.

The term "hydrocarbon" refers to a substituent having a carbon atom attached directly to the remainder of the ligand and is primarily hydrocarbon relative to the scope of this embodiment. Such substituents include the following:

Hydrocarbon substituent

Examples of the hydrocarbon substituent include an aliphatic substituent such as alkyl and alkenyl; an alicyclic substituent such as cycloalkyl and cycloalkenyl; an aromatic, aliphatic or alicyclic substituted aromatic nucleus; and a cyclic group wherein the ring is completed by another portion of the ligand (i.e., any two substituents shown may together form an alicyclic group).

Substituted hydrocarbon substituent

Examples of the substituted hydrocarbon group include those in which the above-mentioned hydrocarbon substituent is substituted with a non-hydrocarbon group which does not change the properties of the hydrocarbon. Specifically, examples of the non-hydrocarbon group include a halogen group such as chlorine and fluorine, an amino group, alkoxy group, mercapto group, alkylmercapto group, nitro group, nitrous group and sulfoxy group.

In the general formula (b22-1), as the anionic ligand selected as L, preferred are ligands derived from an alkylxanthogenate, carboxylate, dialkyldithiocarbamate or a mixture thereof, and ligands derived from a dialkyldithiocarbamate are more preferable.

In the general formula (b22-1), the anion which can be selected as A may be a monovalent or divalent anion, and examples of the anion which can be selected as A include a disulfide, hydroxide, alkoxide, amide, thiocyanate and derivatives thereof.

In the general formula (b22-1), examples of Q include water, amine, alcohol, ether and phosphine. Although the groups Q may be the same or different from each other, they are preferably equal to each other.

As the component (B22), preferred is the compound having the general formula (b22-1), wherein k is an integer of 4 to 7, n is 1 or 2; L is a monoanionic ligand, p is an integer for imparting electrical neutrality to the compound based on an anionic charge in A; and m and z are each 0; and a compound is more preferable represented by the general formula (b22-1), wherein k is an integer of 4 to 7; L is a monoanionic ligand; n is 4; and p, m and z are each 0.

As the component (B22), for example, a compound having a nucleus represented by the following formula (IV-A) or (IV-B) is preferable. Each core has a net electric charge of +4. Such a core is surrounded by an anionic ligand and optionally an existing anion other than the anionic ligand.

The formation of the trinuclear molybdenum-sulfur compound requires the selection of an appropriate anionic ligand (L) and other anion (A) depending, for example, on the number of nucleus and E atoms present in the nucleus, i. the total anionic charge constituted by a sulfur atom, E atom, if present, L and A, if present, must be -4.

When the anionic charge exceeds -4, the trinuclear molybdenum-sulfur compound may also contain a cation other than molybdenum, for example, an (alkyl) ammonium, amine or sodium. A preferred embodiment of the anionic ligand (L) and another anion (A) is a constitution with four monoanionic ligands.

The molybdenum-sulfur nuclei, for example the structures of formulas (IV-A) and (IV-B), may be linked by means of one or more multidentate ligands, i. a ligand having more than one functional group capable of bonding to a molybdenum atom to form oligomers.

<Other molybdenum-based compounds (B3)>

The lubricant oil composition of one embodiment in this invention may include, as the molybdenum-based compound (B), another molybdenum-based compound (B3) than the components (B1) and (B2) within a range in which the effects of this invention are not impaired ,

Examples of such other molybdenum-based compound (B3) include an amine salt of molybdic acid; and a molybdenum amine complex obtained by the reaction of molybdenum trioxide and / or molybdic acid and an amine compound.

A content of the component (B3) in terms of molybdenum atom is typically 0 to 80 parts by mass, preferably 0 to 50 parts by mass, more preferably 0 to 30 parts by mass, still more preferably 0 to 10 parts by mass, and still more preferably 0 to 3 parts by mass based on Total amount of 100 mass parts of component (B1) expressed as molybdenum atom.

<Organic detergent (C1) based on metal>

The lubricant oil composition of this invention contains, as a detergent (C), the metal-based organic detergent (C1) containing a metal atom selected from an alkali metal atom and an alkaline earth metal atom.

The "organic metal-based cleaner" referred to herein means a compound containing at least one carbon atom and one hydrogen atom at least with an alkali metal atom and / or alkaline earth metal atom, and said compound may further have a hetero atom such as an oxygen atom, sulfur atom and Contain nitrogen atom.

In the lubricant oil composition of this invention, the content of the metal-based organic detergent (C1) expressed as a metal atom is adjusted to 1400 mass ppm or less, thereby achieving an effect of reducing the ash content of the lubricant oil composition.

When the above content is more than 1400 ppm by mass, not only is it difficult to use the obtained lubricant oil composition for an engine installed with an exhaust gas post-processing equipment, but also a value of a friction coefficient of the lubricant oil is obtained. Composition large, so that the lubricating oil composition is poor in the friction-reducing effect.

In the lubricant oil composition of this invention, although the content of the metal-based organic detergent (C1) as the detergent (C) is reduced, in view of the lubricant oil composition (D) as the amine-based hindered antioxidant (D1) contains, as mentioned later, a good cleaning effect.

In the lubricant oil composition of this invention, although the content of the component (C1) in terms of the metal atom is 1400 mass ppm or less based on the total amount (100 mass%) of the lubricant oil composition in view of the stronger one Preservation of the friction-reducing effect, the content more preferably 1250 mass ppm or less, more preferably 1100 mass ppm or less, further preferably 1000 mass ppm or less, even more preferably 800 mass ppm or less and particularly preferably 600 mass ppm or fewer.

With a view to obtaining a lubricating oil composition having improved detergency, the content of the component (C1) in terms of metal atom is preferably 50 mass ppm or more, more preferably 70 mass ppm or more, still more preferably 100 mass ppm or more , More preferably, 150 ppm by mass or more, and particularly preferably 200 ppm by mass or more, based on the total amount (100% by mass) of the lubricant oil composition.

In the lubricant oil composition of an embodiment of this invention, although the blending amount of the component (C) can be controlled so that the content in terms of the metal atom falls within the above range, the content is more preferably 0.01 to 2.8 Mass%, more preferably 0.05 to 2.5 mass%, and more preferably 0.10 to 2.1 mass% based on the total mass (100 mass%) of the lubricant oil composition.

As the metal atom contained in the metal-based organic cleaner (C1), a sodium atom, calcium atom, magnesium atom and barium atom are preferable in view of improving the cleaning effect; a calcium atom and a magnesium atom are more preferable, and a calcium atom is more preferable.

It is preferable that the metal-based organic detergent (C1) contains a calcium-based detergent.

The content of the calcium-based detergent in the metal-based organic detergent (C1) is preferably 70 to 100% by mass, more preferably 80 to 100% by mass, still more preferably 90 to 100% by mass, and still more preferably 95 to 100 Mass% based on the total amount (100 mass%) of the metal-based organic cleaner (C1) contained in the lubricant oil composition.

The metal-based organic cleaning agent (C1) may be used alone or in combination of two or more thereof.

As the metal-based organic cleaner (C1) used in an embodiment of this invention, at least one selected from a metal salicylate, metal phenate and metal sulfonate each containing a metal atom selected from an alkali metal atom and alkaline earth metal atom is preferable, and a mixture of a metal sulfonate and at least one selected from a metal salicylate and metal phenate, more preferably. Said mixture is preferably a mixture of a metal sulfonate and metal salicylate.

The metal salicylate used in an embodiment of this invention is preferably a compound having the following general formula (c1-1); the metal phenate is preferably a compound having the following general formula (c1-2); and the metal sulfonate is preferably a compound having the following general formula (c1-3).

In the general formulas (c1-1) to (c1-3), M is a metal atom selected from an alkali metal atom and an alkaline earth metal atom; preferably sodium atom, calcium atom, magnesium atom or barium atom; more preferably calcium atom or magnesium atom and even more preferably calcium atom.

M ⁺ is an alkaline earth metal atom; preferably a calcium atom, magnesium atom or barium atom; more preferably calcium atom or magnesium atom; and even more preferred calcium atom.

p is a valence of M and is 1 or 2.

q is an integer of 0 or more, preferably an integer of 0 to 3, and more preferably 1 or 2.

R is a hydrogen atom or a hydrocarbon group having a carbon number of 1 to 18.

Examples of the hydrocarbon group which can be selected as R include an alkyl group having a carbon number of 1 to 18, an alkenyl group having a carbon number of 1 to 18, a cycloalkyl group having ring carbon atoms of 3 to 18, aryl group having ring carbon atoms of 6 to 18, alkylaryl group having a carbon number of 7 to 18 and arylalkyl group having a carbon number of 7 to 18.

The organic cleaning agent (C1) based on metal may be any of a neutral salt, basic salt, overbased salt and a mixture thereof.

When a mixture of a neutral salt and at least one selected from a basic salt and an overbased salt is used as a metal-based organic detergent (C1), a ratio of the neutral salt to at least one selected from the basic salt and the overbased one Salt [(neutral salt) / ((over) basic salt)] preferably 1/99 to 99/1, more preferably 10/99 to 90/10, and still more preferably 20/80 to 80/20.

When the metal-based organic detergent (C1) is a neutral salt, a base number of the neutral salt is preferably 0 to 30 mgKOH / g, more preferably 0 to 25 mgKOH / g, and still more preferably 0 to 20 mgKOH / g.

When the metal-based organic detergent (C1) is a basic salt or an overbased salt, a base number of the basic salt or the overbased salt is preferably 100 to 600 mgKOH / g, more preferably 130 to 550 mgKOH / g, further preferably 160 to 500 mgKOH / g, and more preferably 200 to 450 mgKOH / g.

In this specification, the "base number" means a base number measured by the perchloric acid method according to JIS K2501, Section 7: "Petroleum products and lubricating oils-neutralization number test method".

<Alkali metal borate (C2)>

In view of obtaining a lubricant oil composition having improved detergency, it is preferable that the lubricant oil composition of one embodiment of this invention further contains an alkali metal borate (C2) as a detergent (C).

In the lubricant oil composition of a starting example of this invention, the content of the component (C2) in terms of boron atom is preferably 50 to 1000 mass ppm, more preferably 60 to 700 mass ppm, even more preferably 70 to 500 mass ppm, and more preferably 80 to 200 ppm by mass based on the total amount (100% by mass) of the lubricant oil composition.

A content of the component (C2) in terms of boron atom is preferably 0 to 100 parts by mass, more preferably 1 to 80 parts by mass, still more preferably 3 to 50 parts by mass, and more preferably 5 to 40 parts by mass, based on 100 parts by mass of the total amount Component (C1) expressed as a metal atom.

In the lubricating oil composition of an embodiment of this invention, although the blending amount of the component (C2) can be controlled so that the content in terms of the boron atom falls within the above-mentioned range, it is more preferably 0.01 to 2.0 Mass%, more preferably 0.03 to 1.5 mass%, and more preferably 0.05 to 1.0 mass% based on the total amount (100 mass%) of the lubricant oil composition.

From the viewpoint of improving the cleaning effect, a potassium atom or sodium atom is preferable as the alkali metal atom contained in the alkali metal borate (C2), and a potassium atom is more preferable.

The borate is an electrically positive compound (salt) with oxygen and boron and is optionally hydrogenated. Examples of the borate include a salt of a boric acid ion (BO ₃ ^3- ) and a salt of a metaboric acid ion (BO ₂ ^- ). The boronic acid (BO ₃ ^3- ) can form various polymeric ions, for example, a Triborsäureion (B ₃ O ₅ ^- ), a Tetraborsäureion (B ₄ O ₇ ^2- ) and a Pentaborsäureion (B ₅ O ₈ ^- ).

Examples of the alkali metal borate (C2) include sodium tetraborate, sodium pentaborate, sodium hexaborate, sodium octaborate, sodium diborate, potassium metaborate, potassium triborate, potassium tetraborate, potassium pentaborate, potassium hexaborate and potassium octaborate, and an alkali metal borate represented by the following general formula (c2-1) is preferable. M "O _1/2 * mBO _3/2 General formula (c2-1):

In the general formula (c2-1), M "is an alkali metal atom, and is preferably a potassium or sodium atom, and more preferably a potassium atom, and m is a number from 2.5 to 4.5.

The alkali metal borate (C2) used in one embodiment of this invention may be a hydrate.

Examples of the hydrate of the alkali metal borate containing Na ₂ B ₄ O ₇ · 10H ₂ O, NaBO ₂ · 4H ₂ O, KB ₃ O ₅ · 4H ₂ O, K ₂ B ₄ O ₇ · 5H ₂ O, K ₂ B ₄ O ₇ · 8H ₂ O and KB ₅ O ₈ · 4H ₂ O and an alkali metal borate hydrate represented by the following general formula (c2-2) is preferable. M "O _1/2 * mBO _3/2 * nH ₂ O General formula (c2-2):

In the general formula (c2-2), M "and m are the same as in the above-mentioned formula (c2-1), and n is a number of 0.5 to 2.4.

A ratio of the boron atom and the alkali metal atom [(boron atom) / (alkali metal atom)] in the alkali metal borate (C2) is preferably 0.1 / 1 or more, more preferably 0.3 / 1 or more, still more preferably 0.5 / 1 or more and more preferably 0.7 / 1 or more, and it is preferably 5/1 or less, more preferably 4.5 / 1 or less, still more preferably 3.25 / 1 or less, and still more preferably 2.8 / 1 or less.

The alkali metal borate (C2) used in an embodiment of this invention may be used alone or in combination of two or more thereof.

Of these, from the viewpoint of improving detergency and solubility in the base oil (A), the potassium triborate (KB ₃ O ₅ ) and its hydrate (KB ₃ O ₅ .nH ₂ O (n is a number of 0.5 to 2 , 4)), preferably as alkali metal borate (C2).

<Ashless detergent (C3)>

The lubricant oil composition of one embodiment of this invention may further contain an ashless detergent (C3) as a detergent (C).

The blending amount of the component (C3) is preferably 0 to 10.0 mass%, more preferably 0.1 to 8.0 mass%, and still more preferably 0.5 to 6.0 mass% based on the total amount (100 mass%) of the lubricant oil composition.

In the present invention, the ashless detergent (C3) may be used alone or in combination of two or more.

An alkenyl succinimide (C31) and a boronated alkenyl succinimide (C32) are preferred as an ashless detergent (C3).

Examples of the alkenyl succinimide (C31) include an alkenyl succinic acid monoimide represented by the following general formula (c3-1) and an alkenyl succinic acid bisimide represented by the following general formula (c3-2).

Further, a modified polybutenyl succinimide obtained by reacting a compound represented by the following general formula (c3-1) or (c3-2) and one or more selected from an alcohol, aldehyde, ketone, alkylphenol, cyclic carbonate, epoxy compound, organic acid , etc. are used as polybutenyl succinimide (C31).

Examples of the borated alkenyl succinimide include a borated compound of an alkenyl succinimide represented by the following general formula (c3-1) or (c3-2).

In the general formulas (c3-1) and (c3-2), R ^A , R ^A1 and R ^{A2 are} each independently an alkenyl group having a weight average molecular weight (Mw) of 500 to 3,000 (preferably 1,000 to 3,000).

R ^B , R ^B1 and R ^B2 are each independently an alkylene group having a carbon number of 2 to 5.

X1 is an integer from 1 to 10, preferably an integer from 2 to 5, and more preferably 3 or 4.

X 2 is an integer of 0 to 10, preferably an integer of 1 to 4, and more preferably 2 or 3.

Examples of the alkenyl group which can be selected as R ^A , R ^A1 and R ^A2 include a polybutenyl group, a polyisobutenyl group and an ethylene-propylene copolymer. Of these, preferred is a polybutenyl group or a polyisobutenyl group.

The alkenyl succinimide (C31) can be produced, for example, by reacting an alkenyl succinic anhydride obtained by reaction of a polyolefin and maleic anhydride with a polyamine.

Examples of the polyolefin include polymers obtained by polymerizing one or more selected from an α-olefin having a carbon number of 2 to 8, and a copolymer of isobutene and 1-butene is preferable.

Examples of the polyamine include a single diamine such as ethylenediamine, propylenediamine, butylenediamine and pentylenediamine; a polyalkylenepolyamine such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, di (methylethylene) triamine, dibutylenetriamine, tributylenetetramine and pentapentylenehexamine; and a piperazine derivative such as aminoethylpiperazine.

The boronated alkenyl succinimic (C32) may be produced, for example, by reaction of an alkenyl succinic anhydride obtained by reaction of said polyolefin and maleic anhydride with said polyamide and a boron compound.

Examples of the boron compound include boron oxide, boron halide, boric acid, boric anhydride, boric acid ester and ammonium salt of boric acid.

In one embodiment of this invention, in view of improving the cleaning effect, a ratio of the boron atom and the nitrogen atom constituting the boronated alkenylsuccinimide (C32) [B / N] is preferably 0.5 or more, more preferably 0.6 or more, even more preferably 0.8 or more and even more preferably 0.9 or more.

In the lubricant oil composition of one embodiment of this invention, the content of the alkenylsuccinimide-based compound (C31) in terms of nitrogen atom is preferably 10 to 3000 ppm by mass, more preferably 50 to 2000 ppm by mass, even more preferably 100 to 1400 ppm by weight. ppm, and more preferably 200 to 1200 mass ppm based on the total amount (100 mass%) of the lubricant oil composition.

In the lubricant oil composition of one embodiment of this invention, the content of the boronated alkenyl succinimide (C32) in terms of boron atom is preferably 10 to 1000 mass ppm, more preferably 30 to 700 mass ppm, even more preferably 50 to 500 mass ppm and even more preferably 100 to 400 ppm by mass based on the total amount (100% by mass) of the lubricant oil composition.

The content of the boronated alkenyl succinimide (C32) in terms of nitrogen atom is preferably 10 to 1000 mass ppm, more preferably 30 to 700 mass ppm, even more preferably 50 to 500 mass ppm, and still more preferably 100 to 400 mass ppm based on the total amount (100 mass%) of the lubricant oil composition.

In the lubricant oil composition of one embodiment of this invention, it is preferable that the ashless detergent (C3) contains both the alkenyl succinimide (C31) and the boronated alkenyl succinimide (C32).

A ratio of the boronated alkenyl succinimide (C32) in terms of boron atom to the content of alkenyl succinimide (C31) expressed as nitrogen atom [(C32) / (C31)] is preferably 0.5 to 5, more preferably 0.7 to 3, even more preferably 0.8 to 2 and more preferably 0.9 to 1.5.

<Hindered amine antioxidant (D1)>

The lubricant oil composition of this invention contains as the antioxidant (D) the hindered amine antioxidant (D1) in an amount of 900 mass ppm or more in terms of nitrogen atom.

In the lubricant oil composition of this invention, although the content of the metal-based organic detergent (C1) in terms of metal atom is set to 1400 ppm by mass or less, the detergency is improved by the presence of the hindered amine-based antioxidant (D1).

The hindered amine-based antioxidant (D1) does not contain a metal atom, and therefore, it contributes to an improvement in the oxidation prevention performance without increasing the sulfated ash content of the lubricant oil composition, whereby the oxidation deterioration of the lubricant oil composition due to use can be inhibited. Due to the oxidation-preventing performance exhibited by the component (D1), the formation of a slurry after use can be reduced, and the cleaning effect can be well maintained. Maintaining this cleaning effect is effective as compared with the case of using the above-mentioned ashless detergent (C3).

In the lubricant oil composition of this invention, the content of the component (D1) in terms of nitrogen atom is 900 mass ppm or more, preferably 950 mass ppm or more, more preferably 1000 mass ppm or more, still more preferably 1100 mass ppm or more and more preferably 1200 mass ppm or more, and is preferably 2000 mass ppm or less, more preferably 1800 mass ppm or less, even more preferably 1600 mass ppm or less, and more preferably 1500 mass ppm or less the basis of the total amount (100% by mass) of the lubricant oil composition.

In the lubricating oil composition of an embodiment of this invention, although the blending amount of the component (D1) can be controlled so that the content in terms of the nitrogen atom falls within the above range, it is preferably 2.10 to 5.00 mass %, more preferably 2.30 to 4.70 mass%, even more preferably 2.50 to 4.50 mass%, and still more preferably 2.80 to 4.20 mass% based on the total amount (100 Mass%) of the lubricant oil composition.

The hindered amine antioxidant (D1) used in the present invention may be an antioxidant containing a structure represented by the following formula (d).

The hindered amine-based antioxidant (D1) may be used alone or in combination of two or more thereof.

In the formula (d), * 1 and * 2 each mean a binding position to another atom.

More specifically, the hindered amine-based antioxidant (D1) is preferably a compound having the following general formula (d-1) or a compound having the following general formula (d-2), and more preferably a compound having the following general formula (d- 3) or a compound having the following general formula (d-4).

In the general formulas (d-1) to (d-4), the groups R ^{D1 are} each independently a hydrogen atom or an alkyl group having a carbon number of 1 to 10, and preferably a hydrogen atom or an alkyl group having a carbon number of 1 to 3.

In the general formula (d-1), R ^{D2 is} a hydrogen atom, an alkyl group having a carbon number of 1 to 20, cycloalkyl group having ring carbon atoms of 6 to 18, aryl group having ring carbon atoms of 6 to 18, hydroxy group, amino group or a group represented by -O-CO-R '(R' is a hydrogen atom or an alkyl group having a carbon number of 1 to 20).

In the general formula (d-2), Z is an alkylene group having 1 to 20 carbon atoms, cycloalkylene group having ring carbon atoms of 6 to 18, arylene group having ring carbon atoms of 6 to 18, oxygen atom, sulfur atom or a group represented by -O-CO- ( CH ₂ ) _n -CO-O- (n is an integer from 1 to 20).

In the general formula (d-3), R 'represents a hydrogen atom or an alkyl group having a carbon number of 1 to 20.

In the general formula (d-4), n is an integer of 1 to 20.

<Other antioxidant (D2) than component (D1)>

With a view to obtaining a lubricant oil composition having improved oxidation stability, the lubricant oil composition of one embodiment of this invention may further contain another antioxidant (D2) than the component (D1) as the antioxidant (D).

In the lubricant oil composition of one embodiment of this invention, the blending amount of the component (D2) is preferably 0 to 8.0 mass%, more preferably 0.05 to 6.0 mass%, still more preferably 0.1 to 4, 5 mass%, and more preferably 0.3 to 3.0 mass%, based on the total amount (100 mass%) of the lubricant oil composition.

A content of the component (D2) is preferably 0 to 100 parts by mass, more preferably 1 to 80 parts by mass, more preferably 5 to 60 parts by mass, and still more preferably 10 to 50 parts by mass based on 100 parts by mass of the total amount of the component (D1).

Examples of the antioxidant (D2) include a phenol-based antioxidant, an amine-based antioxidant other than the component (D1), a sulfur-based antioxidant, and a phosphorus-based antioxidant.

The antioxidant (D2) may be used alone or in combination of two or more thereof.

Examples of the phenol-based antioxidant include a monophenol-based antioxidant such as 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, isooctyl -3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate and benzoic acid, 3,5-bis (1 , 1-dimethylethyl) -4-hydroxy, C7-C9 side chain alkyl ester; a diphenol-based antioxidant such as 4,4'-methylenebis (2,6-di-tert-butylphenol) and 2,2'-methylenebis (4-ethyl-6-tert-butylphenol); and a different hindered phenol antioxidant than component (D1).

Examples of the other amine-based antioxidant as the component (D1) include a diphenylamine-based antioxidant such as diphenylamine and alkylated diphenylamine having an alkyl group with a carbon number of 3 to 20; and a naphthylamine-based antioxidant such as α-naphthylamine, phenyl-α-naphthylamine and a substituted phenyl-α-naphthylamine having an alkyl group having a carbon number of 3 to 20.

Examples of the sulfur-based antioxidant include dilauryl-3,3'-thiodipropionate.

Examples of the phosphorus-based antioxidant include a phosphite.

Of these, in order to obtain a lubricant oil composition having improved oxidation stability, the component (D2) preferably contains one or more selected from a phenol-based antioxidant (D21) and another amine-based antioxidant (D22) as the component (D1) and More preferably, it contains both the phenol-based antioxidant (D21) and the other amine-based antioxidant (D22) as component (D1).

When component (D2) contains both component (D21) and component (D22), in view of obtaining a lubricant oil composition having improved oxidation stability, a ratio of component (D21) to component (D22) [(D21 ) / (D22)] is preferably 0.1 / 1 to 1.0 / 1, more preferably 0.2 / 1 to 0.9 / 1, and still more preferably 0.3 / 1 to 0.8 / 1 in terms of a mass ratio.

<Zinc dithiophosphate (E1)>

The lubricant oil composition of one embodiment of this invention may further contain a zinc dithiophosphate (ZnDTP) (E1) as an antiwear agent (E).

As mentioned above, when ZnDTP and MoDTC are used together, a film of phosphorus is formed on the metal surface of the engine part, and a film of molybdenum sulfide is further formed on the above-mentioned phosphor film, whereby the abrasion resistance and the friction reducing effect are obtained; such sharing is insufficient for realizing the fuel economy properties which will be required to a greater extent in the future.

On the other hand, in the lubricating oil composition of this invention, further containing ZnDTP, a stronger film of phosphorus derived from ZnDTP and a film of molybdenum sulfide derived from MoDTP may be formed. In addition, in the lubricant oil composition of this invention, it is possible to set the content of ZnDTP to a low value, and therefore, the abrasion resistance and the friction-reducing effect can be more improved with good balance.

Accordingly, in the lubricating oil composition of one embodiment of this invention, even if ZnDTP is further contained, the abrasion resistance can be further improved without lowering the friction-reducing effect.

In the lubricant oil composition of one embodiment of this invention, the content of the component (E1) in terms of zinc atom is preferably 100 to 700 mass ppm, more preferably 150 to 650 mass ppm, even more preferably 200 to 600 mass ppm and More preferably, 250 to 550 mass ppm based on the total amount (100 mass%) of the lubricant oil composition.

When said content is 100 ppm by mass or more, a lubricant oil composition having improved abrasion resistance can be obtained. In addition, when said content is 700 mass ppm or less, lowering of the friction-reducing effect of the obtained lubricant oil composition can be inhibited.

In the lubricating oil composition of an embodiment of this invention, although the blending amount of the component (E1) can be controlled so that the content in terms of the zinc atom falls within the above-mentioned range, it is preferably 0.01 to 1.00 parts -%, more preferably 0.05 to 0.90 mass%, even more preferably 0.1 to 0.85 mass%, and more preferably 0.2 to 0.80 mass% based on the total amount (100 Mass%) of the lubricant oil composition.

A content of the component (E1) expressed as a phosphorus atom is preferably 0 to 300 parts by mass, more preferably 0 to 200 parts by mass, still more preferably 0 to 100 parts by mass, and more preferably 0 to 80 parts by mass based on 100 parts by mass of the total amount of the component (B1), expressed as phosphorus atom.

The zinc dithiophosphate (E1) is preferably a compound having the following general formula (e-1).

The zinc dithiophosphate (E1) may be used alone or in combination of two or more thereof.

In the formula (e-1), R ^E1 to R ^{E4 are} each independently a hydrocarbon group and may be the same or different from each other.

The carbon number of the hydrocarbon group which can be selected as R ^E1 to R ^E4 is preferably 1 to 20, more preferably 1 to 16, still more preferably 3 to 12, and further preferably 3 to 10.

Although examples of the specific hydrocarbon group which can be selected as R ^E1 to R ^E4 include the same hydrocarbon groups as those for the hydrocarbon group represented as R ¹ to R ⁴ in the above-mentioned general formula (b1-1) or (b1-2) An alkyl group is preferable, and a primary or secondary alkyl group is more preferable.

<Other additives for the lubricant oil>

The lubricant oil composition of one embodiment of this invention may contain other additives for the lubricant oil that do not conform to the above components such as an ashless friction modifier, antiabrasion agent, extreme pressure agent, viscosity index improver, metal deactivator, pour point suppressant, rust inhibitor, and anti-foaming agent, within a range in which the effects of this invention are not impaired.

Each of these additives for the lubricant oil may be used alone or in combination of two or more thereof.

Although the content of each of these additives for the lubricant oil may be suitably set within a range in which the effects of this invention are not impaired, it is typically 0.001 to 15 mass%, preferably 0.005 to 10 mass%, and more preferably 0, 01 to 8 mass% based on the total amount (100 mass%) of the lubricant oil composition.

In the lubricant oil composition of one embodiment of this invention, the total content of these additives for the lubricant oil is preferably 0 to 25% by mass, more preferably 0 to 20% by mass, and still more preferably 0 to 15% by mass based on the total amount ( 100% by mass) of the lubricant oil composition.

In this specification, there is the case where the additive such as a viscosity index improver and anti-foaming agent in a form of a solution dissolved in a diluting oil such as mineral oil, synthetic oil and light oil is mixed with other components, the handling properties or solubility in the Base oil (A) are taken into account. In this case, in this specification, the content of the additive such as an anti-foaming agent and a viscosity index improver means the content expressed as the active component (in terms of resin content) from which the diluting oil is eliminated.

Examples of the ashless friction modifier include an aliphatic amine, a fatty acid ester, fatty acid amide, fatty acid, aliphatic alcohol and aliphatic ethers each having at least one alkyl or alkenyl group having a carbon number of 6 to 30, especially a linear alkyl group or linear alkenyl group having a carbon number of 6 to 30 in one molecule thereof.

Examples of the other antiabrasion agent or extreme pressure agent than the above-mentioned components include zinc phosphate; a sulfur-containing compound such as zinc dithiocarbamate, a disulfide, a sulfurized olefin, sulfurized oils and fats, sulfurized esters, thiocarbonate, thiocarbamate and polysulfide; a phosphorus-containing compound such as a phosphite ester, phosphate ester, phosphonate ester and amine salt or metal salt thereof; and a sulfur and phosphorus-containing antiwear agent such as thiophosphite ester, thiophosphate ester, thiophosphonate ester and an amine salt or metal salt thereof.

Examples of the viscosity index improver include a polymethacrylate, a dispersion type polymethacrylate, an olefinic copolymer (e.g., an ethylene-propylene copolymer), a dispersion type olefinic copolymer and a styrenic copolymer (e.g., a styrene-diene copolymer and styrene-isoprene copolymer).

The structure of the viscosity index improver may be linear or branched. In addition, the viscosity index improver used in the present invention may be a polymer having a specific structure such as a comb-like polymer having a structure having a large number of trigeminal branching points, from which a high molecular weight side chain comes out in a main chain thereof; and a star-shaped polymer which is a kind of branched polymer and has a structure in which three or more chain polymers are bonded at one point.

Although a weight average molecular weight (Mw) of such a viscosity index improver is typically 500 to 1,000,000, preferably 5,000 to 800,000, and more preferably 10,000 to 600,000, it is properly adjusted according to the kind of the polymer.

The SSI (Shear Stability Index) of the resin content making up the viscosity index improver is preferably 1 to 30.

The value of SSI means an ability to resist decomposition of the resin content constituting the viscosity index improver. When the value of SSI is higher, the resin content is more unstable and is more likely to be decomposed under shear.

In the specification, the SSI of the resin content constituting the viscosity index improver means a value measured according to ASTM D6278.

Examples of the metal deactivator include a benzotriazole-based compound, tolyltriazole-based compound, thiadiazole-based compound, imidazole-based compound, and pyrimidine-based compound.

Examples of the pour point depressant include an ethylene-vinyl acetate copolymer, a chlorinated paraffin condensate and naphthalene, a chlorinated paraffin condensate and phenol, polymethacrylate and polyalkyl styrene.

Examples of the rust inhibitor include a petroleum sulfonate, alkylbenzenesulfonate, dinonylnaphthalenesulfonate, alkenylsuccinic acid ester and a polyhydric alcohol ester.

Examples of the anti-foaming agent include silicone oil, fluorosilicone oil and fluoroalkyl ether.

[Various properties of lubricant oil composition]

The content of the molybdenum atom in the lubricant oil composition of one embodiment of this invention is preferably 400 to 3000 ppm by mass, more preferably 500 to 2500 ppm by mass, even more preferably 700 to 2000 ppm by mass, even more preferably 800 to 1800 ppm by mass. ppm, and more preferably 900 to 1500 mass ppm based on the total amount (100 mass%) of the lubricant oil composition.

The content of the calcium atom in the lubricant oil composition of one embodiment of this invention is preferably 50 to 1400 mass ppm, more preferably 60 to 1250 mass ppm, even more preferably 70 to 1100 mass ppm, more preferably 80 to 1000 mass ppm even more preferably 90 to 800 ppm by mass, and more preferably 100 to 600 ppm by mass based on the total amount (100% by mass) of the lubricant oil composition.

The content of the phosphorus atom in the lubricant oil composition of one embodiment of this invention is preferably 200 to 1100 mass ppm, more preferably 300 to 1000 mass ppm, even more preferably 400 to 900 mass ppm, and more preferably 500 to 850 mass ppm based on the total amount (100 mass%) of the lubricant oil composition.

A kinematic viscosity at 100 ° C of the lubricant oil composition of an embodiment in this invention is preferably 3 to 20 mm ² / s, more preferably 3 to 10 mm ² / s, and still more preferably 5 to 8 mm ² / s.

A viscosity index of the lubricant oil composition of one embodiment of this invention is preferably 100 or more, more preferably 120 or more, and even more preferably 130 or more.

[Application of Lubricant Oil Composition]

The lubricant oil composition of one embodiment of this invention may be preferably used as a lubricant oil for an internal combustion engine such as a gasoline engine, a diesel engine, and a gas engine of an automobile, e.g. a two-wheeled or four-wheeled vehicle, a power generator and a ship. Because of a low sulfated ash content, the lubricating oil composition of one embodiment of this invention is particularly suitable as a lubricating oil composition for an internal combustion engine provided with an exhaust post-processing equipment (particulate filter or exhaust gas purifying apparatus).

This invention is also suitable for obtaining a method of using a lubricant oil composition using the above-mentioned lubricant oil composition for an internal combustion engine provided with an exhaust gas post-processing device.

As the internal combustion engine using the lubricant oil composition of this invention, for example, a direct injection gasoline engine (namely, a small engine) mounted with a supercharger such as a supercharger and a turbocharger, and a diesel engine are preferable.

In addition, the lubricating oil composition of one embodiment of this invention is also useful as a lubricating oil composition for an internal combustion engine that sufficiently satisfies exhaust gas regulations in the future.

The lubricant oil composition of an embodiment of this invention is suitably used for lubricating each component such as an internal combustion engine when filling in the internal combustion engine, particularly a diesel engine provided with an exhaust gas post-processing equipment.

Production Method of Lubricating Oil Composition

This invention also provides a process for producing a lubricating oil composition having a sulphated ash content of 0.70 mass% or less.

• Schritt (I):
  • einen Schritt der Vermischung
  • eines Grundöls (A);
  • eines Molybdändithiophosphats (B1) in einer Menge von 400 Massen-ppm oder mehr, ausgedrückt als Molybdänatom;
  • eines organischen Reinigungsmittels (C1) auf Metallbasis, das ein Metallatom enthält, ausgewählt aus einem Alkalimetallatom und einem Erdalkalimetallatom in einer Menge von 1400 Massen-ppm oder weniger, ausgedrückt als Metallatom; und
  • ein Antioxidans (D1) auf gehinderter Aminbasis in einer Menge von 900 Massen-ppm oder mehr, ausgedrückt als Stickstoffatom,
  • unter Erhalt einer Schmiermittelöl-Zusammensetzung mit einem sulfatierten Aschegehalt von 0,70 Massen-% oder weniger.

Specifically, the process for producing a lubricant oil composition of this invention includes the following step (I):

• Step (I):
  • a step of mixing
  • a base oil (A);
  • a molybdenum dithiophosphate (B1) in an amount of 400 mass ppm or more in terms of molybdenum atom;
  • an organic metal-based cleaner (C1) containing a metal atom selected from an alkali metal atom and an alkaline earth metal atom in an amount of 1400 mass ppm or less in terms of a metal atom; and
  • an hindered amine antioxidant (D1) in an amount of 900 mass ppm or more in terms of nitrogen atom,
  • to obtain a lubricant oil composition having a sulfated ash content of 0.70 mass% or less.

The components (A), (B1), (C1) and (D1) to be mixed in the step (I) are the same as the respective components contained in the above-mentioned lubricant oil composition of this invention, and the kinds of suitable components and the contents of the respective components are also the same as mentioned above.

The above-mentioned components other than these components may be mixed in this step.

Each of the components to be mixed in the step (I) may be mixed after forming into a solution (dispersion) when added with a diluent oil or the like.

It is preferred that after mixing the respective components, the mixture is stirred and uniformly dispersed.

The properties (e.g., sulfated ash content, contents of various atoms, kinematic viscosity and viscosity index) of the lubricant oil composition obtained by the step (I) are the same as in the lubricant oil composition of this invention as mentioned above.

Examples

This invention will be described below in detail with reference to examples, but it is to be understood that this invention is not limited by these examples. Various physical property values of the respective components used in Examples and Comparative Examples and the resulting lubricating oil compositions were measured according to the following methods.

<Kinematic viscosity at 40 ° C and 100 ° C>

The measurement was carried out according to JIS K 2283.

<Viscosity Index>

The measurement was carried out according to JIS K 2283.

<Aromatic content (% C _A ) and paraffin content (% C _P )>

The measurement was made by ring analysis according to ASTM D-3238 (n-d-M method).

<NOACK value>

The measurement was made in accordance with JPI-5S-41-2004.

<Content of sulfur atom>

The measurement was carried out according to JIS K2541-6.

<Contents of molybdenum atom, calcium atom, boron atom, potassium atom, zinc atom and phosphorus atom>

The measurement was made in accordance with JPI-5S-38-92.

<Content of nitrogen atom>

The measurement was carried out according to JIS K2609.

<Sulphated ash content>

The measurement was carried out according to JIS K2272.

<Base number (perchloric acid method or hydrochloric acid method)>

The measurement was carried out according to JIS K2501.

<SSI (Shear Stability Index)>

The measurement was carried out according to ASTM D6278.

Weight average molecular weight (Mw) and number average molecular weight (Mn)>

The measurement was carried out using a gel permeation chromatograph ("1260 Model HPLC", manufactured by Agilent) under the following conditions, and the values expressed as standard polystyrene were used.

(Measurement Conditions)

• • Column: one in which two "Shodex LF404" are sequentially bonded together.
• • Column temperature: 35 ° C
• • Developing solution agent: chloroform
• Flow rate: 0.3 ml / min

Examples 1 to 13 and Comparative Examples 1 to 6

A base oil and various additives shown below were added in the blending amounts shown in Tables 1 to 3 and mixed thoroughly to prepare the respective lubricant oil compositions.

Details of the base oil and the various additives used in Examples and Comparative Examples are shown below.

<Base Oil>

"Hydrorefined mineral oil (1)":

Mineral oil classified in Group 3 of the API base oil categories, having a kinematic viscosity at 40 ° C of 18.5 mm ² / s, a kinematic viscosity at 100 ° C of 4.15 mm ² / s and a viscosity index of 133.% C _A = 0.1 or less,% Cp = 89.5, content of sulfur atom = less than 5 mass ppm, NOACK value = 13.8 mass%; according to component (A).

<Molybdenum-based compound>

"MoDTP (1)":

ADEKA SAKURA-LUBE 310G (manufactured by Adeka Corporation) having a content of molybdenum atom of 8.5 mass%, a content of phosphorus atom of 5.5 mass% and a sulfur atom content of 13.0 mass%, which is a binuclear molybdenum dialkyldithiophosphate with the general formula (b1-1), wherein X ¹ and X ^{2 are} an oxygen atom; X ³ to X ^{8 are} a sulfur atom and R ¹ to R ^{4 are} each independently a hydrocarbon group; according to component (B1).

"MoDTC (1)":

ADEKA SAKURA-LUBE 515 (manufactured by Adeka Corporation) having a content of molybdenum atom of 10.0 mass% and a sulfur atom content of 11.5 mass%, which is a binuclear molybdenum dialkyldithiocarbamate having the general formula (b21-2) wherein X ¹¹ to X ^{14 are} an oxygen atom; and R ¹¹ to R ^{14 are} each independently a hydrocarbon group having a carbon number of 8 to 13; according to component (B21).

"MoDTC (2)":

Infineum C9455B (manufactured by Infineum) having a content of the molybdenum atom of 5.5% by mass and a content of sulfur atom of 9.9% by mass, which is a trinuclear molybdenum dithiocarbamate having the general formula (b22-1); according to component (B22).

<Detergent>

Cleaning agent (1) based on an organic metal:

Overbased calcium salicylate having a base number (perchloric acid method) of 225 mgKOH / g, a content of the calcium atom of 7.8 mass% and a content of the sulfur atom of 0.15 mass%; according to component (C1).

Cleaning agent (2) based on the organic metal:

Neutral calcium sulfonate having a base number (perchloric acid method) of 17 mgKOH / g, a content of the calcium atom of 2.15 mass% and a content of the sulfur atom of 3.44 mass%; according to component (C1).

Kaliumborathydrat:

Product name "OLOA9750" manufactured by Oronite Japan Ltd. is a compound having the general formula (c2-2) wherein M "is a potassium atom having a base number (perchloric acid method) of 125 mgKOH / g, a boron atom content of 6.8 mass% and a nitrogen atom content of 0.22 mass%; according to component (C2).

Ashless detergent (1):

Polybutenyl group-containing polybutenylsuccinic bisimide having a number average molecular weight of 2300 (compound having the general formula (c3-2)) and having a nitrogen atom content of 0.99 mass%; corresponds to compound (C3).

Ashless detergent (2):

Polybutenyl group-containing polybutenyl succinic acid monoimide borate having a number-average molecular weight of 1,000 (boronated compound of a compound represented by the general formula (c3-1)) having a borate atom content of 1.30 mass% and a nitrogen atom content of 1.23 mass%; according to component (C3).

<Antioxidant>

Antioxidant (1) based on the hindered amine:

Product name "XPDL-590" manufactured by BASF SE containing 2,2,6,6-tetramethylpiperidin-4-yldodecanoate (compound having the general formula (d-3) wherein R ^{D1 is} a hydrogen atom and R 'is an undecyl group) with a nitrogen content of 4.13 mass%; according to component (D1).

Antioxidant (1) based on phenol:

Benzenepropanoic acid, 3,5-bis (1,1-dimethylethyl) -4-hydroxy, C7-C9 side chain alkyl ester; according to component (D2).

Antioxidant (1) based on amine:

Bis (4-nonylphenyl) amine with a nitrogen atom content of 3.5% by mass; according to component (D2).

<Antiwear agents>

ZnDTP (1):

A zinc dialkyldithiophosphate (mixture of a compound represented by the general formula (e-1) wherein R ^E1 to R ^{E4 is} a secondary propyl group and a compound represented by the general formula (e-1) wherein R ^E1 to R ^{E4 are} a secondary hexyl group), with a content of the zinc atom of 7.85 mass%, a content of the phosphorus atom of 7.2 mass% and a content of the sulfur atom of 14.4 mass%; according to component (E1).

<Friktionsmodifizierer>

Ashless friction modifier:

oleyldiethanolamine

<Viscosity>

PMA:

Polyalkyl (meth) acrylate having a weight average molecular weight of 380000 and an SSI of 20.

<Other additives>

Other additives:

Mixture of a metal deactivator; a pour-point suppressant and an anti-foaming agent.

With respect to the lubricant oil composition prepared in Examples and Comparative Examples, the content of the calcium atom (Ca), the content of the phosphorus atom (P), the content of the molybdenum atom (Mo), the base number (hydrochloric acid method), and the sulfated ash content were respectively Measured above method. Using each lubricant oil composition, the following tests were then performed. The results are shown in Tables 1 to 3.

<NOx blowing tests>

NOx blowing tests:

100 g of each lubricant oil composition prepared in Examples and Comparative Examples was heated to 140 ° C. A mixed gas obtained by mixing air at a flow rate of 100 ml / min and a NO gas at a flow rate of 100 ml / min, produced by diluting nitrogen monoxide (NO) with nitrogen (NO concentration: 8000 vol. ppm) was introduced into the lubricating oil composition for 72 hours. Thus, NO x degraded oils were obtained.

Measurement of the base number of NOx-degraded oil:

Using the NOx-degraded oil obtained in the above step (1), a base number (hydrochloric acid method) after the test by the chloric acid method according to JIS K2501 was measured. Then, a reduction amount in the base number before and after the test was also calculated.

Hot tube test of Nox degraded oil:

A test oil containing 1 mass% of 1-ethyl-4-nitrobenzene was prepared by adding 1-ethyl-4-nitrobenzene to the NOx-degraded oil obtained in the above step (1).

Then, a glass tube having an inner diameter of 2 mm was vertically arranged in a heater block; 0.3 ml / h of the prepared test oil and 10 ml / min of air each from a lower part of the glass tube; and a hot tube test was conducted for 16 hours while keeping the temperature of the heater part at 240 ° C.

After conducting the hot tube test for 16 hours, the connection status of a precipitate adhering to the interior of the glass tube was evaluated at 0.5 increments ranging from Scale 0 (black colored) to Scale 10 (colorless: no precipitate). Regarding the evaluations, it can be said that the larger the numerical value, a lubricant oil composition having a smaller volume of precipitate and superior detergency is obtained. In this example, the rating is preferably 6.0 or more, though the case is judged acceptable if the score is 5.0 or more.

In addition, it was also observed whether the precipitate adhered to the upper part of the glass tube after conducting the hot tube test for 16 hours or not.

<Falex wear test>

A Falex tester was used and AISIC1137 / SAE3135 was used as a pin / block. The pin / block was inserted into the Falex tester; 60 g of the lubricating oil composition, which is objective for the test, was introduced inside a test container; the test container was set at a rotation number of 600 rpm, an oil temperature of 80 ° C and a load of 1340 N, measuring a block abrasion amount (mg) and a pin abrasion amount (mg). A numerical value described as "Falex abrasion test: abrasion amount" in Tables 1 to 3 is a value of a total abrasion amount of the block abrasion amount and the pin abrasion amount.

<TE77 reciprocating

Hochgeschwindigkeitsfriktionsmaschine>

A "high-speed reciprocating fryer TE77" (manufactured by Phoenix Tribology Ltd.) was used and a test plate (material: FC250, shape: 58 mm in length x 20 mm in width x 4 mm in thickness) and a test cylinder pin (in material: SUJ-2 , Shape: 6 mm diameter × 14 mm length) were used.

Before the test, an oil temperature of the lubricant oil composition objective for the test was set at 80 ° C, and a running-in operation was 60 minutes at an amplitude of 8 mm, a frequency of 20 Hz and a load of 10 to 200 N. carried out.

Then, a friction coefficient at an amplitude of 8 mm, a frequency of 20 Hz, an oil temperature of 80 ° C and a load of 80 N was performed.

It can be said that the smaller the value of the friction coefficient, a lubricant oil composition having a more excellent friction-reducing effect is obtained.

The results of Tables 1 to 3 show that the lubricating oil compositions prepared in Examples 1 to 13 are excellent in detergency, abrasion resistance and abrasion resistance are low-friction effect with a good balance while the ash content is reduced compared to the lubricant oil compositions prepared in Comparative Examples 1 to 6.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• JP 5163497A [0006]

Claims (15)

Lubricating oil composition containing: a base oil (A); a molybdenum dithiophosphate (B1) in an amount of 400 mass ppm or more in terms of molybdenum atom; an organic metal-based cleaner (C1) containing a metal atom selected from an alkali metal atom and an alkaline earth metal atom in an amount of 1400 mass ppm or less in terms of a metal atom; and an hindered amine antioxidant (D1) in an amount of 900 mass ppm or more in terms of nitrogen atom, with a sulfated ash content of 0.70 mass% or less. Lubricant oil composition after Claim 1 wherein the content of molybdenum dithiocarbamate (B2) in terms of molybdenum atom is 600 mass ppm or less based on the total amount of the lubricant oil composition. Lubricant oil composition after Claim 1 or 2 , further containing a zinc dithiophosphate (E1). Lubricant oil composition after Claim 3 wherein the content of the component (E1) in terms of zinc atom is from 100 to 700 mass ppm based on the total amount of the lubricant oil composition. Lubricating oil composition according to one of Claims 1 to 4 further containing an alkali metal borate (C2). Lubricating oil composition according to one of Claims 1 to 5 wherein the content of the phosphorus atom is from 200 to 1100 ppm by mass based on the total amount of the lubricant oil composition. Lubricating oil composition according to one of Claims 1 to 6 wherein the content of the component (B1) in terms of molybdenum atom is from 400 to 2,000 ppm by mass based on the total amount of the lubricant oil composition. Lubricating oil composition according to one of Claims 1 to 7 wherein component (C1) contains a calcium-based cleanser. Lubricating oil composition according to one of Claims 1 to 8th wherein the content of the component (C1) in terms of the metal atom is from 100 to 1100 ppm by mass based on the total amount of the lubricant oil composition. Lubricating oil composition according to one of Claims 1 to 9 wherein the content of the component (D1) in terms of nitrogen atom is from 900 to 2,000 ppm by mass based on the total amount of the lubricant oil composition. Lubricating oil composition according to one of Claims 1 to 10 wherein the content of the sulfated ash content is from 0.06 to 0.50 mass% based on the total amount of the lubricant oil composition. Lubricating oil composition according to one of Claims 1 to 11 wherein the content of the component (A) is 60 mass% or more based on the total amount of the lubricant oil composition. Lubricating oil composition according to one of Claims 1 to twelve wherein a total blending amount of the component (A), the component (B1), the component (C1) and the component (D1) is 70% by mass or more based on the total amount of the lubricant oil composition. A method of using a lubricant oil composition using the lubricant oil composition according to any one of Claims 1 to 13 , for an internal combustion engine provided with an exhaust gas post-processing device. A process for producing a lubricant oil composition, comprising the following step (I): (I): a step of mixing a base oil (A); a molybdenum dithiophosphate (B1) in an amount of 400 mass ppm or more in terms of molybdenum atom; an organic cleaning agent (C1) based on metal, containing a metal atom selected from an alkali metal atom and an alkaline earth metal atom in an amount of 1400 mass ppm or less in terms of a metal atom; and an amine-hindered antioxidant (D1) in an amount of 900 mass ppm or more, in terms of nitrogen atom, to give a lubricant oil composition having a sulfated ash content of 0.70 mass% or less.