Lubricating oil composition, method for reducing friction of internal combustion engine, and method for producing lubricating oil composition

Abstract

This invention relates to lubricating oil compositions, methods for reducing friction in internal combustion engines, and methods for manufacturing lubricating oil compositions. The invention provides lubricating oil compositions with excellent friction-reducing effects and excellent fuel-saving properties. The lubricating oil composition comprises: (X) a lubricating oil base oil, (A) a dinuclear organomolybdenum compound represented by general formula (I), (B) a trinuclear organomolybdenum compound represented by general formula (II), and (C) an ashless friction modifier having two or more hydroxyl groups within a molecule. The total content of molybdenum atoms in component (A) and component (B) is 0.012% by mass or more, based on the total amount of the lubricating oil composition, and the content of component (C) is less than 2.0% by mass, based on the total amount of the lubricating oil composition. The symbols in formulas (I) and (II) are consistent with those described in the specification. Mo3S k E m L n A p Q z (II)

Description

[0001] This invention application is a divisional application of PCT patent application PCT / JP2016 / 069709, entitled "Lubricating oil composition, method for reducing friction in internal combustion engine, and method for manufacturing lubricating oil composition". The parent application number in China is 201680038159.X. Technical Field

[0002] This invention relates to lubricating oil compositions, methods for reducing friction in internal combustion engines, and methods for manufacturing lubricating oil compositions. Background Technology

[0003] In recent years, efforts to reduce energy consumption and carbon dioxide emissions and improve the fuel efficiency of automobiles have received much attention.

[0004] As a measure to improve the fuel efficiency of automobiles, the lightweighting of vehicle bodies has been promoted, but this also places demands on lubricants that contribute to fuel efficiency. Therefore, researchers involved in lubricant development have studied the reduction of lubricant viscosity and further improvements in friction-reducing properties through lubricants.

[0005] In studies on friction-reducing properties, methods have been employed to incorporate organomolybdenum compounds such as MoDTC into lubricating oil compositions. For example, a lubricating oil composition incorporating organomolybdenum compounds has been proposed in Patent Document 1.

[0006] Existing technical documents Patent documents Patent document 1: Japanese Patent Application Publication No. 2015-010177. Summary of the Invention

[0007] The problem the invention aims to solve Compared to ashless friction modifiers, organic molybdenum compounds exhibit superior friction-reducing effects, particularly in boundary lubrication zones. Therefore, various engine oils containing organic molybdenum compounds have been developed.

[0008] However, simply adding organic molybdenum compounds is insufficient to further address fuel-saving (friction-reducing) goals.

[0009] The purpose of this invention is to provide a lubricating oil composition that has excellent friction-reducing effect and excellent fuel-saving properties.

[0010] Methods for solving problems To address the aforementioned issues, the addition of ashless friction modifiers to organomolybdenum compounds was considered. However, reports indicate that the friction-reducing effect of organomolybdenum compounds is impaired and the coefficient of friction increases when ashless friction modifiers are added.

[0011] The inventors conducted research on the combination of organic molybdenum compounds and ashless friction modifiers, which takes into account the increased friction coefficient. They found that by combining specific organic molybdenum compounds with specific ashless friction modifiers, friction can be reduced dramatically, thereby solving the aforementioned problem.

[0012] That is, the present invention provides the lubricating oil composition described below [1] to [3], the method for reducing friction in an internal combustion engine, and the method for manufacturing the lubricating oil composition.

[0013] [1] A lubricating oil composition comprising: (X) a lubricating oil base oil, (A) a dinuclear organomolybdenum compound of general formula (I) below, (B) a trinuclear organomolybdenum compound of general formula (II) below, and (C) an ashless friction modifier having two or more hydroxyl groups in the molecule, wherein the total molybdenum atom-converted content of component (A) and the total molybdenum atom-converted content of component (B) is 0.012% by mass or more based on the total amount of the lubricating oil composition, and the content of component (C) is less than 2.0% by mass based on the total amount of the lubricating oil composition. [Chemical Formula 1] In formula (I), R 1 ~R 4 R represents a hydrocarbon group with 7 to 22 carbon atoms. 1 ~R 4 They can be the same or different; X 1 ~X 4 [Represents sulfur or oxygen atoms]; Mo3S k E m L n A p Q z (II) [In formula (II), E is independently oxygen or selenium; K is an integer of at least 1, m is 0 or an integer, k+m is 4 to 10; L is independently an anionic ligand having an organic group containing carbon atoms, wherein the total number of carbon atoms in the organic group in each ligand is 14 or more, and the ligands may be the same or different; N is an integer from 1 to 4; A is an anion other than L; p is 0 or an integer; Q is independently a neutral electron-donating compound; z is an integer from 0 to 5, including non-stoichiometric values].

[0014] [2] A method for reducing friction in an internal combustion engine, wherein the lubricating oil composition described above [1] is added to the internal combustion engine.

[0015] [3] A method for manufacturing a lubricating oil composition, comprising the steps of mixing (X) a lubricating oil base oil, (A) a dinuclear organomolybdenum compound of the above general formula (I), (B) a trinuclear organomolybdenum compound of the above general formula (II), and (C) an ashless friction modifier having two or more hydroxyl groups in its molecule. Perform the aforementioned mixing steps to ensure that: The total molybdenum atom-converted content of component (A) and component (B), calculated based on the total amount of the lubricating oil composition, reaches 0.012% by mass or more, and The content of the aforementioned component (C) is less than 2.0% by mass based on the total amount of the lubricating oil composition.

[0016] The effects of the invention The lubricating oil composition and the method for reducing friction in an internal combustion engine of the present invention have excellent friction-reducing effects and can achieve good fuel economy. Furthermore, the manufacturing method of the lubricating oil composition of the present invention can produce a lubricating oil composition with excellent friction-reducing effects and good fuel economy. Detailed Implementation

[0017] The embodiments of the present invention will be described below.

[0018] [Lubricating oil composition] The lubricating oil composition of this embodiment comprises: (X) a lubricating oil base oil, (A) a dinuclear organomolybdenum compound represented by general formula (I) below, (B) a trinuclear organomolybdenum compound represented by general formula (II) below, and (C) an ashless friction modifier having two or more hydroxyl groups in its molecule. The total content of molybdenum atoms in component (A) and component (B) is 0.012% by mass or more based on the total amount of the lubricating oil composition, and the content of component (C) is less than 2.0% by mass based on the total amount of the lubricating oil composition. [Chemical Formula 2] In formula (I), R 1 ~R 4 R represents a hydrocarbon group with 7 to 22 carbon atoms. 1 ~R 4 They can be the same or different; X 1 ~X 4 [Represents sulfur or oxygen atoms]; Mo3S k E m L n A p Q z (II) [In formula (II), E is independently oxygen or selenium; k is an integer of at least 1, m is 0 or an integer, k+m is 4 to 10; L is independently an anionic ligand having an organic group containing carbon atoms, wherein the total number of carbon atoms in the organic group in each ligand is 14 or more, and the ligands may be the same or different; n is an integer from 1 to 4; A is an anion other than L; p is 0 or an integer; Q is independently a neutral electron-donating compound; z is an integer from 0 to 5, including non-stoichiometric values].

[0019] <(X) Lubricating Oil Base Oil> The lubricating oil composition of this embodiment includes (X) a lubricating oil base oil. Examples of lubricating oil base oils that are components (X) include mineral oils and / or synthetic oils.

[0020] Examples of mineral oils include: paraffin-based mineral oils, intermediate-based mineral oils, and naphthenic-based mineral oils obtained through conventional refining methods such as solvent refining and hydrorefining; and wax isomerization oils produced by isomerizing waxes such as GTL waxes and mineral oil-based waxes manufactured using the Fischer-Tropsch process. Mineral oils are preferably those classified as Group 3 in the American Petroleum Institute's base oil classification system.

[0021] Examples of synthetic oils include hydrocarbon-based synthetic oils and ether-based synthetic oils. Examples of hydrocarbon-based synthetic oils include α-olefin oligomers such as polybutene, polyisobutylene, 1-octene oligomers, 1-decene oligomers, and ethylene-propylene copolymers or their hydrides, as well as alkylbenzenes and alkylnaphthalenes. Examples of ether-based synthetic oils include polyoxyalkylene glycols and polyphenylene ethers.

[0022] (X) Component can be a single system using one of the above-mentioned mineral oils and synthetic oils, or it can be a mixed system such as a substance obtained by mixing two or more mineral oils, a substance obtained by mixing two or more synthetic oils, or a substance obtained by mixing one or more mineral oils and synthetic oils.

[0023] (X) The preferred composition has a kinematic viscosity of 2.5~3.0 mm at 100℃. 2 / s, and %C obtained through ndM ring analysis p It is over 80%.

[0024] By making the kinematic viscosity of component (X) at 100°C 2.5 mm 2 At a speed of 6s or higher, the increase in the coefficient of friction over time due to the evaporation of the lubricating oil composition can be suppressed. Furthermore, by setting the kinematic viscosity of component (X) at 100°C to 3.0 mm... 2 Below / s, it can reduce high-temperature high-shear viscosity (HTHS viscosity) and suppress the increase in the coefficient of friction. Furthermore, the %C obtained by ndM ring analysis of the (X) component...p With a viscosity of over 80%, it can suppress the increase in the coefficient of friction over time due to the evaporation of the lubricating oil composition, while also reducing HTHS viscosity and suppressing the increase in the coefficient of friction.

[0025] Therefore, by making the kinematic viscosity of component (X) at 100°C 2.5~3.0 mm... 2 / s and %C obtained through ndM ring analysis p With a friction reduction rate of over 80%, it achieves excellent fuel economy.

[0026] The kinematic viscosity of component (X) at 100°C is more preferably 2.6~3.0 mm. 2 / s, further preferably 2.7~3.0mm 2 / s.

[0027] (X) component obtained by ndM ring analysis %C p More preferably, it is 82% or more, and even more preferably, it is 82-95%.

[0028] A more preferred size is 2.6~3.0mm. 2 / s, further preferably 2.7~3.0mm 2 / s.

[0029] The content of component (X) is preferably 60% by mass or more, more preferably 70 to 95% by mass, and even more preferably 75% by mass or more and 90% by mass or less, based on the total amount of the lubricating oil composition.

[0030] <Organomolybdenum compounds> The lubricating oil composition of this embodiment comprises (A) a dinuclear organomolybdenum compound represented by general formula (I) below, and (B) a trinuclear organomolybdenum compound represented by general formula (II) below. Furthermore, in the lubricating oil composition of this embodiment, the total content of molybdenum atoms in component (A) and the total content of molybdenum atoms in component (B), based on the total amount of the lubricating oil composition, is 0.012% by mass or more. [Chemical Formula 3] In formula (I), R 1 ~R 4 R represents a hydrocarbon group with 7 to 22 carbon atoms. 1 ~R 4 They can be the same or different; X 1 ~X 4 [Represents sulfur or oxygen atoms]; Mo3S k E m L n A pQ z (II) [In formula (II), E is independently oxygen or selenium; k is an integer of at least 1, m is 0 or an integer, k+m is 4 to 10; L is independently an anionic ligand having an organic group containing carbon atoms, wherein the total number of carbon atoms in the organic group in each ligand is 14 or more, and the ligands may be the same or different; n is an integer from 1 to 4; A is an anion other than L; p is 0 or an integer; Q is independently a neutral electron-donating compound; z is an integer from 0 to 5, including non-stoichiometric values].

[0031] Typically, when organic molybdenum compounds are used in combination with ashless friction reducers, the friction-reducing effect of the organic molybdenum compounds is impaired, and the coefficient of friction increases.

[0032] However, in the lubricating oil composition of this embodiment, as an organomolybdenum compound, by combining the binuclear organomolybdenum compound of component (A) and the triuclear organomolybdenum compound of component (B), and by making the total molybdenum atom content of component (A) and the molybdenum atom content of component (B) 0.012% by mass or more based on the total amount of the lubricating oil composition, the coefficient of friction can be significantly reduced by utilizing its synergistic effect with the ashless friction reducer described later (C).

[0033] On the other hand, without either component (A) or (B), the friction-reducing effect of the organomolybdenum compound is impaired, and the coefficient of friction increases, even when using the ashless friction reducer (C) described later. Furthermore, even when components (A) and (B) are used in combination, if the total content of components (A) and (B) is less than 0.012% by mass, the absolute amount of the organomolybdenum compound, which forms the basis of the friction-reducing effect, is insufficient, leading to an increase in the coefficient of friction.

[0034] The total molybdenum atom content of component (A) and component (B), based on the total amount of the lubricating oil composition, is preferably 0.012 to 0.125% by mass, more preferably 0.015 to 0.120% by mass, even more preferably 0.020 to 0.080% by mass, and particularly preferably 0.025 to 0.055% by mass. By setting the total amount of component (A) and component (B) within this range, the friction reduction effect achieved by utilizing their synergistic effect with component (C) described later can be improved, while suppressing turbidity and precipitation caused by the influence of components (A) and (B) at low temperatures.

[0035] Furthermore, the molybdenum atom content of component (A) is preferably 0.002 to 0.100% by mass based on the total amount of the lubricating oil composition, and the molybdenum atom content of component (B) is preferably 0.001 to 0.030% by mass based on the total amount of the lubricating oil composition.

[0036] By setting the contents of components (A) and (B) within this range, the friction reduction effect achieved by utilizing their synergistic effect with component (C) (described later) can be improved, while suppressing turbidity and precipitation caused by the influence of components (A) and (B) in low-temperature environments.

[0037] The molybdenum content of component (A), calculated based on the total amount of the lubricating oil composition, is more preferably 0.005 to 0.080% by mass, and even more preferably 0.010 to 0.050% by mass.

[0038] (B) The molybdenum content, calculated based on the total amount of the lubricating oil composition, is more preferably 0.002 to 0.025% by mass, and even more preferably 0.005 to 0.020% by mass.

[0039] Furthermore, the ratio of [molybdenum atom content of component (A) / molybdenum atom content of component (B)] is preferably 0.1 to 25.0, more preferably 0.1 to 7.5, further preferably 1.0 to 5.0, and even more preferably 1.5 to 3.0.

[0040] In general formula (I), R 1 ~R 4 R represents a hydrocarbon group with 7 to 22 carbon atoms. 1 ~R 4 They can be the same or different. If R 1 ~R 4 If the number of carbon atoms in each component is less than 6, the oil solubility is poor. If R 1 ~R 4 When the number of carbon atoms in a carbon atom reaches 23 or more, the melting point increases, the processability decreases, and the friction-reducing ability decreases. Based on the above viewpoints, R... 1 ~R 4 The number of carbon atoms in each component is preferably 7 to 18, more preferably 7 to 14, and particularly preferably 8 to 13. Furthermore, R 1 ~R 4 The total number of carbon atoms is preferably 34 to 80, more preferably 36 to 60, and even more preferably 38 to 54.

[0041] As R 1 ~R 4 Examples of hydrocarbon groups include alkyl, alkenyl, alkylaryl, cycloalkyl, and cycloalkenyl groups, preferably branched or straight-chain alkyl or alkenyl groups, and more preferably branched or straight-chain alkyl groups. Examples of branched or straight-chain alkyl groups include n-octyl, 2-ethylhexyl, isononyl, n-decyl, isodecyl, dodecyl, tridecyl, and isotriadecyl.

[0042] Furthermore, from the viewpoints of solubility in base oils, storage stability, and friction reduction capabilities, R is preferred among the dinuclear organomolybdenum compounds represented by general formula (I). 1 With R 2 For the same alkyl group, R 3 With R 4 For the same alkyl group, and R 1 and R 2 alkyl and R 3 and R 4 The alkyl groups are different.

[0043] Furthermore, in general formula (I), X 1 ~X 4 X represents a sulfur atom or an oxygen atom. 1 ~X 4 They can be the same or different.

[0044] X contains sulfur and oxygen atoms. 1 ~X 4 When sulfur atoms are used, the ratio of sulfur atoms to oxygen atoms is preferably 1 / 3 to 3 / 1, more preferably 1 / 2 to 3 / 1, and even more preferably 1.5 to 2.5 to 3 / 1. By making X... 1 ~X 4 The ratio of sulfur atoms to oxygen atoms is within the aforementioned range, resulting in good performance in terms of corrosion resistance and solubility in lubricating base oils.

[0045] In addition, X 1 ~X 4 It can consist entirely of sulfur atoms or oxygen atoms.

[0046] (B) The trinuclear organomolybdenum compound is represented by the above general formula (II).

[0047] In general formula (II), each L is an anionic ligand having an organic group containing carbon atoms, and the total number of carbon atoms in the organic group of each ligand is 14 or more. The ligands may be the same or different, but are preferably the same. If the total number of carbon atoms in the organic group of each ligand is 13 or less, the solubility in the base oil decreases. The total number of carbon atoms in the organic group of each ligand is preferably 14 to 50, more preferably 16 to 30, and even more preferably 18 to 24.

[0048] The preferred anionic ligand is a monoanionic ligand (a 1-valent anionic ligand).

[0049] Each ligand is preferably selected from any of the ligands shown, for example, by the following general formulas (III-A) to (III-D).

[0050] [Chemical Formula 4] In formulas (III-A), (III-B), (III-C), and (III-D), X 31 ~X 37 Y and each are independently an oxygen atom or a sulfur atom; furthermore, in formulas (III-A), (III-B), (III-C), and (III-D), R 31 ~R 35 As independent organic groups, R 31 ~R 35 They can be the same or different; R 31 ~R 33 The organic groups have 14 or more carbon atoms. R 34 The number of carbon atoms in the organic group and R 35 The total number of carbon atoms in the organic groups is 14 or more.

[0051] R 31 ~R 33 The organic group preferably has 14 to 50 carbon atoms, more preferably 16 to 30, and even more preferably 18 to 24. 34 The number of carbon atoms in the organic group and R 35 The total number of carbon atoms in the organic groups is preferably 14 to 50, more preferably 16 to 30, and even more preferably 18 to 24. Furthermore, R 34 The number of carbon atoms in the organic groups and R 35 The number of carbon atoms in the organic groups is preferably 7 to 30, more preferably 7 to 20, and even more preferably 8 to 13.

[0052] R 34 organic groups and R 35 The organic groups can be the same or different, preferably different. Furthermore, R 34 The number of carbon atoms in the organic group and R 35 The number of carbon atoms in the organic groups can be the same or different, preferably different.

[0053] In general formula (II), the ligand preferably includes the ligand shown in general formula (III-D) above.

[0054] Furthermore, in general formula (II), it is preferable that all ligands are the same, and more preferably all ligands are the ligands shown in the above general formula (III-D).

[0055] The organic groups mentioned above are preferably hydrocarbon groups such as alkyl, aryl, substituted aryl, and ether groups. More preferably, each ligand has the same hydrocarbon group.

[0056] The term "hydrocarbon group" refers to a substituent having a carbon atom directly bonded to the ligand residue, and within the scope of this embodiment, its characteristics are primarily hydrocarbon groups. Examples of such substituents include the following.

[0057] 1. Hydrocarbon substituents Examples of hydrocarbon substituents include aliphatic substituents such as alkyl and alkenyl; alicyclic substituents such as cycloalkyl and cycloalkenyl; aromatic nuclei substituted by aromatic groups, aliphatic groups, and alicyclic groups; and cyclic groups whose rings are closed by means of another location in the ligand (i.e., any two exemplary substituents can be used together to form an alicyclic group).

[0058] 2. Substituted hydrocarbon substituents Examples of substituents for hydrocarbons include groups obtained by replacing the aforementioned hydrocarbon substituents with non-hydrocarbon groups that do not alter the properties of the hydrocarbon group. Examples of non-hydrocarbon groups include, in particular, halogen groups such as chlorine and fluorine, amino groups, alkoxy groups, mercapto groups, alkyl mercapto groups, nitro groups, nitroso groups, and sulfonyloxy groups.

[0059] Preferred ligands include alkyl xanthates, carboxylates, dialkyl dithiocarbamates, and mixtures thereof. Dialkyl dithiocarbamates are most preferred.

[0060] In general formula (II), E (oxygen or selenium) may replace sulfur, for example, in the nucleus described later. k+m is preferably 4 to 7.

[0061] Furthermore, examples of Q in general formula (II) include water, amines, alcohols, ethers, and phosphine. Q may be the same or different, but is preferably the same. The neutral electron-donating compound Q exists to fill the vacant coordination sites on the trinuclear molybdenum compound.

[0062] Furthermore, the anion of A in general formula (II) can be either a monovalent or a divalent anion. Specific examples of A include disulfides, hydroxides, alkoxys, amines, and thiocyanates, or their derivatives.

[0063] In one embodiment of general formula (II), k is 4 to 7, n is either 1 or 2, L is a monoanionic ligand, p is an integer that imparts electrical neutrality to the compound based on the anionic charge in A, and m and z are 0.

[0064] Furthermore, in a further embodiment of general formula (II), k is 4 to 7, L is a monoanionic ligand, n is 4, and p, m and z are 0.

[0065] Furthermore, trinuclear organomolybdenum compounds of general formula (II) have nuclei, for example, those shown in formula (IV-A) or (IV-B). Each nucleus has a net electrical charge of +4. These nuclei are surrounded by anionic ligands and anions other than the anionic ligands, which may be present as needed.

[0066] [Chemical Formula 5] .

[0067] Those skilled in the art will understand that the formation of a trinuclear molybdenum-sulfur compound depends, for example, on the number of sulfur and E atoms present in the nucleus, and requires the selection of appropriate anionic ligands (L) and other anions (A) (“E”, “L”, and “A” denote “E”, “L”, and “A” of general formula (II)). Specifically, the total anionic charge of the sulfur atom, the optionally present E atom, L, and the optionally present A must be -4. Furthermore, when the anionic charge of the trinuclear molybdenum-sulfur compound exceeds -4, it may contain cations other than molybdenum, such as (alkyl)ammonium, amine, or sodium. A preferred embodiment of the anionic ligands (L) and other anions (A) is a configuration having four monoanionic ligands.

[0068] The molybdenum-sulfur nuclei, such as the structures shown in (IV-A) and (IV-B) above, can be interconnected by one or more polydentate ligands, that is, by ligands that are bonded to molybdenum atoms and have more than one functional group capable of forming oligomers.

[0069] Trinuclear organomolybdenum compounds can be prepared by, for example, the methods described below (1) to (3). The solvents used in (1) to (3) can be, for example, aqueous solvents or organic solvents.

[0070] (1) In a suitable solvent, make (NH4)2Mo3S 13 Molybdenum sources such as n(H2O) (where n varies between 0 and 2, including non-stoichiometric values) react with suitable ligand sources such as tetraalkylthiuram disulfide.

[0071] (2) In a suitable solvent, make (NH4)2Mo3S 13 Molybdenum sources such as ·n(H2O) react with ligand sources such as tetraalkylthiuram disulfide and dialkyl dithiocarbamate, as well as desulfurizing agents such as cyanide ions and sulfite ions.

[0072] (3) React trinuclear molybdenum-thiohalide salts such as [M']2[Mo3S7A6] (where M' is an anti-charge ion and A is a halogen such as Cl, Br or I) with ligand sources such as dialkyl dithiocarbamate in a suitable solvent.

[0073] It should be noted that the lubricating oil composition of this embodiment may further contain mononuclear organic molybdenum compounds, provided that the friction-reducing effect is not impaired.

[0074] In this embodiment, (B) the trinuclear organomolybdenum compound is preferably a dithiocarbamate compound, such as a trinuclear molybdenum dithiocarbamate. Particularly effective compounds are molybdenum dialkyl dithiocarbamate compounds represented by the formula Mo3S7((alkyl)2dtc)4.

[0075] <(C) Ashless Friction Modifier> In the lubricating oil composition of this embodiment, as component (C), an ashless friction modifier having two or more hydroxyl groups in its molecule is included, and the (C) component is included in an amount of less than 2.0% by mass based on the total amount of the lubricating oil composition.

[0076] As mentioned above, when organic molybdenum compounds are typically used in combination with ashless friction reducers, the friction-reducing effect of the organic molybdenum compounds is impaired, and the coefficient of friction increases. However, the lubricating oil composition of this embodiment, by containing a specific amount of a specific organic molybdenum compound and a specific amount of (C) component, can dramatically reduce the coefficient of friction.

[0077] On the other hand, even with so-called ashless friction reducers, the friction-reducing effect of organomolybdenum compounds is impaired when using substances that do not meet the conditions for component (C) (e.g., substances with only one hydroxyl group in the molecule), leading to an increase in the coefficient of friction. Furthermore, even when using component (C), if the content reaches 2.0% by mass or higher, the friction-reducing effect of organomolybdenum compounds is compromised, and the coefficient of friction instead increases.

[0078] The content of component (C) is preferably 0.1 to 1.5% by mass, more preferably 0.3 to 1.0% by mass, based on the total amount of the lubricating oil composition. By setting the content of component (C) within this range, the friction reduction effect achieved by its synergistic effect with the organomolybdenum compound can be further utilized, resulting in better fuel economy.

[0079] Examples of ashless friction modifiers having two or more hydroxyl groups within the molecule, which are components (C), include ester compounds, amine compounds, and amide compounds. Among these, amine compounds and amide compounds are preferred, with amine compounds being the most preferred. From the viewpoint of friction reduction effect and solubility in base oil, the number of hydroxyl groups within the molecule of component (C) is preferably 2 to 6, more preferably 2.

[0080] As an example of component (C), namely ester compounds, compounds of the following general formula (V) can be cited.

[0081] [Chemical Formula 6] .

[0082] In general formula (V), R 51 It is a hydrocarbon group with 1 to 32 carbon atoms.

[0083] R 51 The number of carbon atoms in the hydrocarbon group is preferably 8 to 32, more preferably 12 to 24, and even more preferably 16 to 20.

[0084] As R 51 Examples of hydrocarbon groups include alkyl, alkenyl, alkylaryl, cycloalkyl, and cycloalkenyl. Among these, alkyl or alkenyl is preferred, with alkenyl being the most preferred.

[0085] As R 51 The alkyl groups in the formula can include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecanyl, octadecyl, nonadecanyl, eicosyl, dodecyl, tridecyl, and tetradecyl, and can be any of the following: linear, branched, or cyclic.

[0086] In addition, as R 51 Examples of alkenyl groups include vinyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecanyl, octadecenyl, nonadecanyl, icosyl, icosyl, icosyl, icosyl, icosyl, tridecenyl, and tetradecenyl. They can be linear, branched, or cyclic, and the position of the double bond is arbitrary.

[0087] R 52 ~R 56 These are either hydrogen atoms or hydrocarbon groups with 1 to 18 carbon atoms, and they may be the same or different from each other. R 52 ~R 56 Ideally, all atoms should be hydrogen atoms.

[0088] R 52 ~R 56 When the group is a hydrocarbon group, it can be saturated or unsaturated, aliphatic or aromatic, and linear, branched or cyclic.

[0089] When using the compound represented by the above general formula (V) as component (C), R can be used. 51 ~R 56 All are the same single type, and R can also be 51 ~R 56 A portion of different kinds (e.g., R)51 Two or more types of materials (with different numbers of carbon atoms and the presence or absence of double bonds) are mixed and used together.

[0090] Examples of compounds represented by general formula (V) include glycerol monolaurate, glycerol monostearate, glycerol monomyristate, and glycerol monooleate, among other glycerol fatty acid monoesters. Glycerol monooleate is a suitable example.

[0091] As an example of component (C), namely amine compounds, compounds of the following general formula (VI) can be cited.

[0092] [Chemical Formula 7] .

[0093] In the above general formula (VI), R 61 It is a hydrocarbon group with 1 to 32 carbon atoms.

[0094] R 61 The number of carbon atoms in the hydrocarbon group is preferably 8 to 32, more preferably 10 to 24, and even more preferably 12 to 20.

[0095] As R 61 Examples of hydrocarbon groups include alkyl, alkenyl, alkylaryl, cycloalkyl, and cycloalkenyl. Among these, alkyl or alkenyl is preferred.

[0096] As R 61 The alkyl groups in the formula can include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecanyl, octadecyl, nonadecanyl, eicosyl, dodecyl, tridecyl, and tetradecyl, and can be any of the following: linear, branched, or cyclic.

[0097] In addition, as R 61 Examples of alkenyl groups include vinyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecanyl, octadecenyl, nonadecanyl, icosyl, icosyl, icosyl, icosyl, icosyl, tridecenyl, and tetradecenyl. They can be linear, branched, or cyclic, and the position of the double bond is arbitrary.

[0098] R 62 ~R 69 It is a hydrogen atom, a hydrocarbon group having 1 to 18 carbon atoms, or an oxygen-containing hydrocarbon group containing an ether bond or an ester bond, which may be the same or different from each other, preferably a hydrogen atom or a hydrocarbon group, wherein, preferably a hydrogen atom. Furthermore, R 62 ~R69 Ideally, all atoms should be hydrogen atoms.

[0099] As R 62 ~R 69 The hydrocarbon group can be saturated or unsaturated, aliphatic or aromatic, and linear, branched, or cyclic. Examples include aliphatic hydrocarbon groups such as alkyl or alkenyl, or aromatic hydrocarbon groups. More specifically, examples include methyl, ethyl, propyl, butyl, butenyl, hexyl, hexenyl, octyl, octenyl, 2-ethylhexyl, nonyl, decyl, undecyl, decenyl, dodecyl, dodecenyl, tridecyl, tetradecyl, tetradecenyl, pentadecyl, hexadecyl, hexadecenyl, heptadecanyl, octadecyl, octadecenyl, stearyl, isostearyl, oleyl, linoleyl, cyclopentyl, cyclohexyl, methylcyclohexyl, ethylcyclohexyl, propylcyclohexyl, dimethylcyclohexyl, trimethylcyclohexyl, etc. (aliphatic hydrocarbon groups), and aromatic hydrocarbon groups such as phenyl, methylphenyl, ethylphenyl, dimethylphenyl, propylphenyl, trimethylphenyl, butylphenyl, naphthyl, etc.

[0100] The hydrocarbon group is preferably a hydrocarbon group with 1 to 18 carbon atoms, more preferably a hydrocarbon group with 1 to 12 carbon atoms, even more preferably a hydrocarbon group with 1 to 4 carbon atoms, and most preferably a hydrocarbon group with 2 carbon atoms.

[0101] Examples of oxygen-containing hydrocarbon groups containing ether or ester bonds, such as groups with 1 to 18 carbon atoms, include methoxymethyl, ethoxymethyl, propoxymethyl, isopropoxymethyl, n-butoxymethyl, tert-butoxymethyl, hexoxymethyl, octoxymethyl, 2-ethylhexoxymethyl, decaoxymethyl, dodecyloxymethyl, 2-butyloctoxymethyl, tetradecyloxymethyl, hexadecyloxymethyl, 2-hexyldodecyloxymethyl, allyloxymethyl, phenoxy, benzyloxy, methoxyethyl, and methoxy Propyl, 1,1-dimethoxypropyl, 1,2-dimethoxypropyl, ethoxypropyl, (2-methoxyethoxy)propyl, (1-methyl-2-methoxy)propyl, acetoxymethyl, propionyloxymethyl, butyryloxymethyl, hexanoyloxymethyl, octanoyloxymethyl, 2-ethylhexanoyloxymethyl, decanoyloxymethyl, dodecanoyloxymethyl, 2-butyloctanoyloxymethyl, tetradecanoyloxymethyl, hexadecanoyloxymethyl, 2-hexyldodecanoyloxymethyl, benzoyloxymethyl, etc.

[0102] Furthermore, in the above general formula (VI), a and b represent integers from 1 to 20, respectively.

[0103] a+b is preferably 2~20, more preferably 2~10, further preferably 2~4, and most preferably 2.

[0104] When using the compound represented by the above general formula (VI) as component (C), R can be used. 61 ~R 69 A single type where a~b are all the same can also be R. 61 ~R 69 A subset of different kinds from a to b (e.g., R) 61 Different carbon atoms and the presence or absence of double bonds can be used by mixing two or more types.

[0105] Specific compounds of general formula (VI) include amine compounds having two 2-hydroxyalkyl groups, such as octyl diethanolamine, decyl diethanolamine, dodecyl diethanolamine, tetradecyl diethanolamine, hexadecyl diethanolamine, stearyl diethanolamine, oleylene diethanolamine, coconut oil diethanolamine, palm oil diethanolamine, rapeseed oil diethanolamine, and tallow diethanolamine; and amine compounds having two polyoxyalkylene structures, such as polyoxyethylene octylamine, polyoxyethylene decylamine, polyoxyethylene dodecylamine, polyoxyethylene tetradecylamine, polyoxyethylene hexadecylamine, polyoxyethylene stearylamine, polyoxyethylene oleylamine, polyoxyethylene tallow amine, polyoxyethylene coconut oil amine, polyoxyethylene palm oil amine, polyoxyethylene laurylamine, polyoxyethylene stearylamine, polyoxyethylene oleylamine, and ethylene oxide propylene oxide stearylamine. Among these, stearyl diethanolamine and oleylene diethanolamine are preferred.

[0106] As an example of component (C), namely amide compounds, compounds of the following general formula (VII) can be cited.

[0107] [Chemical Formula 8] .

[0108] R in general formula (VII) 71 The implementation method is the same as R in the above general formula (VI). 61 The implementation method is the same. Furthermore, R in general formula (VII) 72 ~R 79 The implementation methods of a and b are the same as those of the general formula (VI) above. 62 ~R 69 The implementation methods of a and b are the same.

[0109] Specific compounds of general formula (VII) include amide compounds having two 2-hydroxyalkyl groups, such as octyl diethanolamide, decyl diethanolamide, dodecyl diethanolamide, tetradecyl diethanolamide, hexadecyl diethanolamide, stearyl diethanolamide, oleylene diethanolamide, coconut oil diethanolamide, palm oil diethanolamide, rapeseed oil diethanolamide, and tallow diethanolamide; and amide compounds having two polyoxyalkylene structures, such as polyoxyethylene octylamide, polyoxyethylene decylamide, polyoxyethylene dodecylamide, polyoxyethylene tetradecylamide, polyoxyethylene hexadecylamide, polyoxyethylene stearylamide, polyoxyethylene oleylene amide, polyoxyethylene tallow amide, polyoxyethylene coconut oil amide, polyoxyethylene palm oil amide, polyoxyethylene laurylamide, polyoxyethylene stearylamide, polyoxyethylene oleylene amide, and ethylene oxide propylene oxide stearylamide. Among these, oleylene diethanolamide is preferred.

[0110] Furthermore, in the lubricating oil composition of this embodiment, the ratio of [content of component (C) / (content of component (A) based on molybdenum atoms + content of component (B) based on molybdenum atoms)] is preferably 3.0 to 50.0, more preferably 5.0 to 40.0, and even more preferably 10.0 to 35.0. By using this ratio, the friction-reducing effect achieved by the synergistic effect of components (A) and (B) with component (C) can be further enhanced, resulting in better fuel economy.

[0111] In the lubricating oil composition of this embodiment, the total content of component (A), component (B) and component (C) is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 87% by mass or more, based on the total amount of the lubricating oil composition.

[0112] It should be noted that the lubricating oil composition of this embodiment may contain other ashless friction modifiers, to the extent that the friction reduction effect is not impaired.

[0113] <(D) Viscosity Index Improver> In order to further improve fuel efficiency, the lubricating oil composition of this embodiment preferably contains a (D) viscosity index improver.

[0114] As a viscosity index improver for component (D), comb-shaped polymers are suitable. "Comb-shaped polymers" refers to polymers with a structure having three-way branching points on the main chain with multiple branching linear side chains.

[0115] As such comb-shaped polymers, examples preferably include polymers having at least a structural unit derived from a macromonomer having polymerizable functional groups such as (meth)acryloyl, vinyl, vinyl ether, and allyl. Here, the structural unit is equivalent to a "linear side chain".

[0116] More specifically, examples include: alkyl (meth)acrylates; copolymers in which the main chain of structural units of various vinyl monomers derived from nitrogen-containing systems, halogen-containing systems, hydroxyl-containing systems, aliphatic hydrocarbon systems, alicyclic hydrocarbon systems, aromatic hydrocarbon systems, etc., has side chains derived from structural units of macromolecular monomers having the aforementioned polymerizable functional groups.

[0117] The number-average molecular weight (Mn) of the macromonomer is preferably 200 to 100,000, more preferably 300 to 10,000, and even more preferably 400 to 50,000 or more.

[0118] As viscosity index improvers for component (D), poly(meth)acrylate, olefin copolymers, polyisobutylene, etc. can be used.

[0119] For viscosity index improvers of component (D), in order to further improve fuel efficiency and prevent sticking, a weight-average molecular weight of 300,000 or more and an SSI of 10.0 or less are preferred.

[0120] The weight-average molecular weight (Mw) of component (D) is more preferably 300,000 to 500,000, and even more preferably 350,000 to 420,000.

[0121] It should be noted that in this embodiment, "weight-average molecular weight" refers to the molecular weight of polystyrene determined by gel permeation chromatography (GPC).

[0122] Furthermore, from the viewpoint of achieving good fuel-saving performance in the assumed low-temperature region during engine start-up, the molecular weight distribution (Mw / Mn) of component (D) is preferably lower than 2.0. It should be noted that there is a tendency for a smaller molecular weight distribution of component (D) to result in better fuel-saving performance in the assumed low-temperature region during engine start-up.

[0123] Furthermore, the lower limit value of the molecular weight distribution of component (D) is not particularly limited, but is generally 1.01 or more, preferably 1.05 or more, and more preferably 1.10 or more.

[0124] The SSI of component (D) is more preferably 8.0 or less, further preferably 5.0 or less, and particularly preferably less than 2.0. By making the weight-average molecular weight 420,000 or less, it is easy to make the SSI 10.0 or less.

[0125] Here, SSI refers to the Shear Stability Index, which represents the polymer's ability to resist decomposition. The higher the SSI, the less stable the polymer is to shear stress and the easier it is to decompose.

[0126] [Mathematical Expression 1] .

[0127] SSI represents the viscosity reduction due to shearing originating from the polymer, calculated using the formula above. In the formula, Kv0 is the kinematic viscosity at 100°C of the mixture obtained by adding component (D) to the base oil. Kv1 is the kinematic viscosity at 100°C of the mixture obtained by adding component (D) to the base oil after 30 cycles using a high-shear Bosch diesel injector according to ASTM D6278. Furthermore, Kv... oil This is the kinematic viscosity of the base oil at 100°C. It should be noted that, as a base oil, a kinematic viscosity of 5.35 mm at 100°C is used. 2 Group II base oil with a viscosity index of 105 and a viscosity index of 105.

[0128] From the viewpoint of saving fuel consumption, the content of component (D) is preferably 0.2 to 5.0% by mass, more preferably 0.4 to 3.0% by mass, and even more preferably 0.8 to 2.5% by mass, based on the total amount of the lubricating oil composition.

[0129] Here, the content of component (D) refers to the content of the resin component alone, and is based on the content of solid components, excluding the mass of diluent oil and other components contained with component (D).

[0130] The monomer constituting the poly(meth)acrylate, as an example of component (D), is an alkyl (meth)acrylate, preferably a straight-chain alkyl (meth)acrylate with 1 to 18 carbon atoms or a branched alkyl (meth)acrylate with 3 to 34 carbon atoms.

[0131] Preferred monomers for constituting (E) poly(meth)acrylate include, for example, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, pentyl methacrylate, hexyl methacrylate, heptyl methacrylate, octyl methacrylate, nonyl methacrylate, decyl methacrylate, dodecyl methacrylate, tetra(meth)acrylate, hexa(meth)acrylate, octadecyl methacrylate, etc. Copolymers can be prepared using two or more of these monomers. The alkyl groups of these monomers can be linear or branched.

[0132] In addition, examples of alkyl (meth)acrylates having branched alkyl groups having 3 to 34 carbon atoms include isopropyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 3,5,5-trimethylhexyl (meth)acrylate, 2-butyloctyl (meth)acrylate, 2-hexyldecyl (meth)acrylate, 2-octyldodecyl (meth)acrylate, 2-decyltetradecyl (meth)acrylate, 2-dodecylhexadecyl (meth)acrylate, and 2-tetradecyloctadecyl (meth)acrylate.

[0133] In the lubricating oil composition of this embodiment, the total content of component (A), component (B), component (C) and component (D) is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more, based on the total amount of the lubricating oil composition.

[0134] <Optional Added Ingredients> The lubricating oil composition of this embodiment may contain, as an optional additive, one or more selected from pour point depressants, zinc dialkyl dithiophosphate, antioxidants, metal detergents and other ashless detergents.

[0135] The total content of these optional additives is approximately 0.1 to 15% by mass, based on the total amount of the lubricating oil composition.

[0136] <Physical Properties of Lubricating Oil Compositions> In the lubricating oil composition of this embodiment, from the viewpoint of reducing friction over a wide temperature range from low to high, the kinematic viscosity, viscosity index, HTHS viscosity (high temperature high shear viscosity), rate of change of kinematic viscosity after shear test, and NOACK value are preferably within the following ranges.

[0137] From the perspective of fuel efficiency, the kinematic viscosity at 80°C is preferably 5~9 mm. 2 / s, more preferably 6~8mm 2 From the perspective of ensuring oil pressure in high-temperature regions, the kinematic viscosity at 120°C is preferably 3~5 mm. 2 / s, more preferably 3.5~4.5mm 2 / s.

[0138] The viscosity index is preferably 250~340, more preferably 270~320.

[0139] Kinematic viscosity and viscosity index were determined according to JIS K2283:2000.

[0140] From the viewpoint of fuel efficiency, the HTHS viscosity at 80°C is preferably 3.7~4.6 mPa·s, more preferably 4.0~4.3 mPa·s. The HTHS viscosity at 100°C is preferably 2.7~3.6 mPa·s, more preferably 3.0~3.3 mPa·s. From the viewpoint of ensuring an oil film in the high-temperature, high-shear region, the HTHS viscosity at 150°C is preferably 1.5~2.3 mPa·s, more preferably 1.7~2.0 mPa·s.

[0141] HTHS viscosity was determined according to ASTM D4683 and ASTM D6616 using a TBS viscometer (Tapered Bearing Simulator Viscometer) at a shear rate of 10. 6 The measurements were taken under the following conditions: speed (motor) of 3000 rpm and spacing (rotor-stator spacing) of 3 μm.

[0142] The rate of change of kinematic viscosity after the shear test, as measured according to JPI-5S-29, is preferably 2.00% or less, more preferably 1.00% or less. More specifically, the rate of change of kinematic viscosity after the shear test can be determined by the method described in the examples.

[0143] The NOACK value at 250°C for 1 hour, as measured according to ASTM D5800, is preferably 20-50, more preferably 30-40.

[0144] <Applications of Lubricating Oil Compositions> The application of the lubricating oil composition of this embodiment is not particularly limited, and it can be suitably used in various internal combustion engine applications such as four-wheel drive vehicles and two-wheel drive vehicles. Examples of internal combustion engines include gasoline engines, diesel engines, engines using dimethyl ether as fuel, and gas engines.

[0145] Methods to reduce friction in internal combustion engines In this embodiment of the method for reducing friction in an internal combustion engine, the lubricating oil composition of this embodiment described above is added to the internal combustion engine.

[0146] According to the method for reducing friction in an internal combustion engine according to this embodiment, the friction reduction effect can be significantly improved through the synergistic effect of components (A), (B), and (C), resulting in good fuel economy.

[0147] [Method for manufacturing lubricating oil composition] The method for manufacturing the lubricating oil composition of this embodiment includes the steps of mixing (X) a lubricating oil base oil, (A) a dinuclear organomolybdenum compound represented by general formula (I) below, (B) a trinuclear organomolybdenum compound represented by general formula (II) below, and (C) an ashless friction modifier having two or more hydroxyl groups in its molecule. Perform the aforementioned mixing steps to ensure that: The total molybdenum atom-converted content of component (A) and component (B), calculated based on the total amount of the lubricating oil composition, reaches 0.012% by mass or more, and The content of the aforementioned component (C) is less than 2.0% by mass based on the total amount of the lubricating oil composition; [Chemical Formula 9] In formula (I), R 1 ~R 4 R represents a hydrocarbon group with 7 to 22 carbon atoms. 1 ~R 4 They can be the same or different; X 1 ~X 4 [Represents sulfur or oxygen atoms]; Mo3S k E m L n A p Q z (II) [In formula (II), E is independently oxygen or selenium; k is an integer of at least 1, m is 0 or an integer, k+m is 4 to 10; L is independently an anionic ligand having an organic group containing carbon atoms, wherein the total number of carbon atoms in the organic group in each ligand is 14 or more, and the ligands may be the same or different; n is an integer from 1 to 4; A is an anion other than L; p is 0 or an integer; Q is independently a neutral electron-donating compound; z is an integer from 0 to 5, including non-stoichiometric values].

[0148] According to the method for manufacturing the lubricating oil composition of this embodiment, a lubricating oil composition that can significantly improve friction reduction and achieve good fuel economy can be easily manufactured. Example

[0149] The invention will now be described in more detail by way of examples, but the invention is not limited to these examples at all.

[0150] 1. Preparation of the lubricating oil compositions of the examples and comparative examples The lubricating oil compositions of the Examples and Comparative Examples were prepared according to the compositions shown in Tables 1-6. The following materials were used in the preparation of the lubricating oil compositions.

[0151] <(X) component lubricating oil base oil> [Lubricating oil base oil 1] Group III, 70N hydrotreated base oil, kinematic viscosity at 100°C: 2.9 mm 2 / S, Viscosity index: 121, %C obtained through ndM ring analysis p 84.0% [Lubricating oil base oil 2] Group II, 70N hydrotreated base oil, kinematic viscosity at 100°C: 2.9 mm 2 / S, viscosity index: 105, %C obtained through ndM ring analysis p 72.5% [Lubricating oil base oil 3] Group III, 70N hydrotreated base oil, kinematic viscosity at 100°C: 3.1 mm. 2 / S, viscosity index: 123, %C obtained through ndM ring analysis p 84.3% [Lubricating oil base oil 4] Group II, 60N hydrotreated base oil, kinematic viscosity at 100°C: 2.4 mm 2 / S, viscosity index: 115, %C obtained through ndM ring analysis p 80.8%.

[0152] <(A) component dinuclear organomolybdenum compound> [Organomolybdenum compound 1] R 1 ~R 4 Each has 8 or 13 carbon atoms, R 1 ~R 4 The total number of carbon atoms is 42, and X 1 ~X 4 It is a dinuclear organomolybdenum compound with the general formula (I) for oxygen atoms. The molybdenum content is 10.0% by mass, and the sulfur content is 11.5% by mass.

[0153] <(B) Trinuclear organomolybdenum compounds> [Organomolybdenum compound 2] Trinuclear organomolybdenum compounds of general formula (II) having a ligand of general formula (III-D) and a nucleus of general formula (IV-B). R of general formula (III-D) 34 and R 35 The total number of carbon atoms is 21. In general formula (II), k is 7, L is a monoanionic ligand, n is 4, and p, m, and z are 0. The molybdenum content is 5.27% by mass.

[0154] <Mononuclear organomolybdenum compounds> [Organomolybdenum compound 3] A mixture of [2,2'-(dodecanoylimino)diethyl ketone]dioxomolybdenum (VI) and [3-(dodecanoyloxy)-1,2-propanedione]dioxomolybdenum (VI). The molybdenum content is 7.9% by mass, and the nitrogen content is 2.8% by mass.

[0155] [Organomolybdenum compound 4] Diisotridecylamine molybdate. Molybdenum content: 10.0% by mass.

[0156] <(C) Component Ashless Friction Modifier> [Ashless Friction Modifier 1] oleyl diethanolamine [Ashless Friction Modifier 2] Stearyl diethanolamine [Ashless Friction Modifier 3] oleyl diethanolamide [Ashless Friction Modifier 4] Glyceryl monooleate.

[0157] <Other Ashless Friction Modifiers> [Ashless Friction Modifier 5] stearylamine [Ashless Friction Modifier 6] Oil alcohol.

[0158] <(D) viscosity index improver> [Viscosity Index Improver 1] As a resin component, it is a comb-shaped polymer (Mw: 370,000, SSI: 0.9, Mw / Mn less than 2.0) with structural units derived from macromonomers with Mn of 500 or more. [Viscosity Index Improver 2] As a resin component, it is a comb-shaped polymer (Mw: 430,000, SSI: 13.5, Mw / Mn: 2.0 or more) with structural units derived from macromolecular monomers with Mn of 500 or more.

[0159] <Pour Depressant> Alkyl polymethacrylate (weight average molecular weight: 62,000).

[0160] <Additive Kit> A set containing zinc dialkyl dithiophosphate, antioxidants, metal-based detergents, and ash-free detergents.

[0161] 2. Measurement and Evaluation The lubricating oil compositions of the Examples and Comparative Examples prepared with the compositions shown in Tables 1-6 were evaluated as follows. The results are shown in Tables 1-6.

[0162] 2-1. Kinematic viscosity, viscosity index, HTHS viscosity, and NOACK value According to the instructions, the kinematic viscosity, viscosity index, HTHS viscosity, and NOACK value of the lubricating oil composition were measured (250°C, 1 hour).

[0163] 2-2. Change rate of kinematic viscosity after shear test According to JIS K2283:2000, the kinematic viscosity at 100°C before and after the shear test was measured, and the rate of change of kinematic viscosity after the shear test was calculated using the following formula. Furthermore, in the shear test, based on JPI-5S-29, 30 cycles of shear testing were conducted using the Bosch method with diesel engine injectors. The rate of change of kinematic viscosity after shear test = (([kinematic viscosity before test] - [kinematic viscosity after test]) / [kinematic viscosity before test]) × 100.

[0164] 2-3. Coefficient of friction (reciprocating motion friction test) The coefficient of friction was determined using a Phoenix Tribology TE77 reciprocating friction tester under the following conditions.

[0165] (Experimental board) Material: FC250 Shape: 58mm (length) × 20mm (width) × 4mm (thickness) (Test cylindrical pin) Material: SUJ-2 Shape: 6mm in diameter × 14mm in length (Break-in operating conditions) The test was conducted for 60 minutes under the following conditions: stroke of 8mm, 20Hz, oil temperature of 80℃, and load of 10-200N. (Main experimental conditions) The stroke is 8mm, the frequency is 20Hz, the oil temperature is 80℃, and the load is 80N.

[0166] 2-4. Low-temperature stability The lubricating oil compositions of Examples 1-5 and Comparative Example 5 were left to stand at -5°C for 5 days. The low-temperature stability was evaluated by visually confirming the return to the precipitation state at room temperature (20°C). The presence of turbidity and precipitation was recorded as "A", the presence of turbidity but no precipitation was recorded as "B", and the presence of precipitation was recorded as "C".

[0167] [Table 1] .

[0168] Although the lubricating oil compositions of Comparative Examples 1-4 contain an ashless friction modifier of component (C), they do not contain either component (A) or component (B). Compared with the lubricating oil composition of Example 1, the coefficient of friction of the lubricating oil compositions of Comparative Examples 1-4 increased. Therefore, it can be confirmed that in order to exhibit the friction reduction effect achieved by utilizing the synergistic effect of the organomolybdenum compound and component (C), it is necessary to use components (A) and (B) in combination as the organomolybdenum compound. Furthermore, the results of Comparative Examples 3 and 4 confirm that even when a dinuclear or trinuclear organomolybdenum compound is used in combination with a mononuclear organomolybdenum compound, it is impossible to exhibit the friction reduction effect achieved by utilizing its synergistic effect with component (C).

[0169] [Table 2] .

[0170] Although the lubricating oil composition of Comparative Example 5 contains components (A), (B), and (C), the total molybdenum atom conversion content of components (A) and (B) is low. Compared with the lubricating oil compositions of Examples 1-5, the coefficient of friction of the lubricating oil composition of Comparative Example 5 is increased. Therefore, it can be confirmed that a specified amount of components (A) and (B) is necessary to exhibit a friction-reducing effect.

[0171] Furthermore, the results of Examples 1-5 confirm that lubricating oil compositions with a total molybdenum atom conversion content of components (A) and (B) of 0.012% by mass or more can exhibit a friction reduction effect achieved by utilizing its synergistic effect with component (C).

[0172] Furthermore, it was confirmed that in the lubricating oil compositions of Examples 1-4, the organomolybdenum compounds did not precipitate even at low temperatures, demonstrating excellent low-temperature stability. In particular, the lubricating oil compositions of Examples 1-3 did not become cloudy even at low temperatures, exhibiting extremely excellent low-temperature stability.

[0173] [Table 3] .

[0174] The lubricating oil composition of Comparative Example 6 contains components (A) and (B), but not component (C), which is an ashless friction modifier. In contrast to the lubricating oil composition of Comparative Example 6, the lubricating oil composition of Example 1 exhibits a sharply reduced coefficient of friction. Therefore, it can be confirmed that by combining components (A) and (B) as organomolybdenum compounds and using component (C), a friction-reducing effect is achieved through the synergistic effect of the organomolybdenum compound and component (C).

[0175] Furthermore, although the lubricating oil compositions of Comparative Examples 7 and 8 contain components (A) and (B) and an ashless friction modifier, the ashless friction modifier does not have more than two hydroxyl groups. Compared with the lubricating oil composition of Comparative Example 6, the coefficient of friction of the lubricating oil compositions of Comparative Examples 7 and 8 increases. Therefore, it can be confirmed that when an ashless friction modifier without more than two hydroxyl groups is added to the organomolybdenum compounds of components (A) and (B), the friction-reducing effect of the organomolybdenum compounds is impaired.

[0176] [Table 4] .

[0177] Although the lubricating oil composition of Comparative Example 9 contains components (A), (B), and (C), the content of ashless friction modifier in component (C) is high. Compared with the lubricating oil compositions of Examples 1, 6-8, the coefficient of friction of the lubricating oil composition of Comparative Example 9 is increased. Therefore, it can be confirmed that when the content of ashless friction modifier in component (C) is too high, friction actually increases.

[0178] Furthermore, a comparison between Examples 1, 6-8 and Comparative Examples 6, 9 confirms that lubricating oil compositions with a content of component (C) of less than 2.0% by mass based on the total amount of the lubricating oil composition exhibit good friction-reducing effects. In particular, it can be confirmed that the lubricating oil compositions of Examples 1, 6, and 7, with a content of component (C) of less than 1.0% by mass based on the total amount of the lubricating oil composition, exhibit extremely good friction-reducing effects.

[0179] [Table 5] .

[0180] Examples 9-11 changed the type of component (C) in Example 1. The results of Examples 1, 9-11 confirm that ashless friction modifiers having two or more hydroxyl groups within the molecule exhibit friction-reducing effects regardless of their type. Furthermore, a comparison of Examples 1, 9-11 confirms that among components (C), amine-based (Example 1) and amide-based (Examples 9 and 10) components exhibit excellent friction-reducing effects, especially the amine-based (Example 1) component, which demonstrates exceptionally good performance.

[0181] [Table 6] .

[0182] Example 12 changed the type of component (D) in Example 1. A comparison between Example 1 and Example 12 confirms that by including a viscosity index improver with a weight-average molecular weight of 300,000 or more and an SSI of less than 2.0 in the lubricating oil composition, the HTHS viscosity can be reduced, the rate of change of kinematic viscosity after shear test can be reduced, and good fuel economy and tackiness can be achieved.

[0183] Examples 13-15 changed the type of component (X) in Example 1. A comparison between Example 1 and Examples 13-15 clearly shows that by making the kinematic viscosity of the lubricating oil base oil of component (X) at 100°C 2.5-3.0 mm... 2 / s, and %C obtained through ndM ring analysis p With a content of over 80%, it can reduce HTHS viscosity and decrease NOACK value, thus achieving good fuel economy.

[0184] In Tables 1-6, [mass%Mo] represents the molybdenum atom conversion content of the organic molybdenum compound relative to the total amount of the lubricating oil composition.

[0185] Industrial applicability The lubricating oil composition of this embodiment exhibits excellent friction reduction and achieves good fuel economy. Therefore, the lubricating oil composition of this embodiment is suitable for various internal combustion engine applications, such as four-wheel drive vehicles and two-wheel drive vehicles. Examples of internal combustion engines include gasoline engines, diesel engines, engines using dimethyl ether as fuel, and gas turbine engines.

Claims

1. A lubricating oil composition comprising: (X) Lubricating oil base oil, (A) The following general formula (I) represents a dinuclear organomolybdenum compound, (B) The trinuclear organomolybdenum compound represented by the following general formula (II), and (C) Ashless friction modifiers having two or more hydroxyl groups within the molecule The total molybdenum atom content of component (A) and the molybdenum atom content of component (B), calculated based on the total amount of the lubricating oil composition, is 0.012% by mass or more. The content of component (C) is less than 2.0% by mass based on the total amount of the lubricating oil composition. [Chemical Formula 1] In equation (I), R 1 ~R 4 R represents a hydrocarbon group with 7 to 22 carbon atoms. 1 ~R 4 They can be the same or different; X 1 ~X 4 Represents a sulfur atom or an oxygen atom; Mo3S k E m L n A p Q z (II) In formula (II), E is independently oxygen or selenium; k is an integer of at least 1, m is 0 or an integer, and k+m is 4 to 10; L is independently an anionic ligand having an organic group containing carbon atoms, wherein the total number of carbon atoms in the organic group of each ligand is 14 or more, and the ligands may be the same or different; n is an integer from 1 to 4; A is an anion other than L; p is 0 or an integer; Q is independently a neutral electron-donating compound; and z is an integer from 0 to 5, including non-stoichiometric values.

2. The lubricating oil composition according to claim 1, wherein, Each ligand of formula (II) is selected from any of the ligands shown in the following general formulas (III-A), (III-B), (III-C) and (III-D). [Chemical Formula 2] In equations (III-A), (III-B), (III-C), and (III-D), X 31 ~X 37 Y and each are independently an oxygen atom or a sulfur atom; furthermore, in formulas (III-A), (III-B), (III-C), and (III-D), R 31 ~R 35 As independent organic groups, R 31 ~R 35 They can be the same or different; R 31 ~R 33 The organic groups have 14 or more carbon atoms; R 34 The number of carbon atoms in the organic group and R 35 The total number of carbon atoms in the organic groups is 14 or more.

3. The lubricating oil composition according to claim 1 or 2, wherein, The total molybdenum atom content of component (A) and molybdenum atom content of component (B) is 0.012 to 0.125 by mass, based on the total amount of the lubricating oil composition.

4. The lubricating oil composition according to any one of claims 1 to 3, wherein, The molybdenum content of component (A), calculated based on the total amount of the lubricating oil composition, is 0.002 to 0.100% by mass, and the molybdenum content of component (B), calculated based on the total amount of the lubricating oil composition, is 0.001 to 0.030% by mass.

5. The lubricating oil composition according to any one of claims 1 to 4, wherein, The content of component (C) is 0.1 to 1.5% by mass based on the total amount of the lubricating oil composition.

6. The lubricating oil composition according to any one of claims 1 to 5, wherein, The content of component (C) / (content of component (A) converted to molybdenum atoms + content of component (B) converted to molybdenum atoms) is 3.0 to 50.

0.

7. The lubricating oil composition according to any one of claims 1 to 6, wherein, The kinematic viscosity of component (X) at 100°C is 2.5~3.0 mm. 2 / s, %C obtained through ndM ring analysis p It is over 80%.

8. The lubricating oil composition according to any one of claims 1 to 7, further comprising (D) a viscosity index improver.

9. The lubricating oil composition according to claim 8, wherein, The weight average molecular weight of component (D) is above 300,000 and the SSI is below 10.

0.

10. The lubricating oil composition according to any one of claims 1 to 9, further comprising one or more selected from pour point depressants, zinc dialkyl dithiophosphate, antioxidants, metal-based detergents, and ashless detergents.

11. The lubricating oil composition according to any one of claims 1 to 10, used in an internal combustion engine.

12. A method for reducing friction in an internal combustion engine, comprising adding the lubricating oil composition according to any one of claims 1 to 10 to the internal combustion engine.

13. A method for manufacturing a lubricating oil composition, comprising the steps of mixing (X) a lubricating oil base oil, (A) a dinuclear organomolybdenum compound of general formula (I) below, (B) a trinuclear organomolybdenum compound of general formula (II) below, and (C) an ashless friction modifier having two or more hydroxyl groups in its molecule. Perform the mixing step such that: The total molybdenum atom-converted content of component (A) and the molybdenum atom-converted content of component (B), calculated based on the total amount of the lubricating oil composition, reaches 0.012% by mass or more, and The content of component (C) is less than 2.0% by mass based on the total amount of the lubricating oil composition. [Chemical Formula 3] In equation (I), R 1 ~R 4 R represents a hydrocarbon group with 7 to 22 carbon atoms. 1 ~R 4 They can be the same or different; X 1 ~X 4 Represents a sulfur atom or an oxygen atom; Mo3S k E m L n A p Q z (II) In formula (II), E is independently oxygen or selenium; k is an integer of at least 1, m is 0 or an integer, and k+m is 4 to 10; L is independently an anionic ligand having an organic group containing carbon atoms, wherein the total number of carbon atoms in the organic group of each ligand is 14 or more, and the ligands may be the same or different; n is an integer from 1 to 4; A is an anion other than L; p is 0 or an integer; Q is independently a neutral electron-donating compound; and z is an integer from 0 to 5, including non-stoichiometric values.

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