Lubricating oil composition

Abstract

A lubricating oil composition characterized by containing (A) a lubricating oil base oil; (B1) a first amide compound and / or a salt thereof, said first amide compound being a monoamide of a fatty acid (a1) and an amine compound (a2), said amine compound (a2) being an oligomer of an alkanolamine (a3) of general formula (1); (B2) a second amide compound having a structure in which the amino group of an alkanolamine (a3) and one or more hydroxyl groups are acylated with a fatty acid (a1); equation (eq1) is satisfied. MB2 > = 0.50 MB1... (eq1) (In the formula, MB1 and MB2 are respectively the contents (mass%) of the first amide compound and the component (B2). ) Chemical Formula 1 # imgabs0 # (In the formula, n is 1 or 2; r1 represents a linear alkylene group having 1-4 carbon atoms, or a branched alkylene group having 3-10 carbon atoms and 2 carbon atoms in the main chain; the plurality of R1s may be the same as or different from each other. ).

Description

Technical Field

[0001] The present invention relates to a lubricating oil composition, and more particularly, to a lubricating oil composition preferably used for lubrication of an electric motor. Background Art

[0002] In recent years, from the perspective of energy efficiency and environmental adaptability, electric vehicles using electric motors as driving power sources and hybrid vehicles using electric motors and internal combustion engines as driving power sources have attracted attention. Electric motors generate heat as they run, and electric motors contain parts with weak heat resistance, such as coils and magnets. Therefore, in these cars that use electric motors as driving power sources, a mechanism for cooling the electric motors is provided. As mechanisms for cooling electric motors, air cooling, water cooling, and oil cooling are known. Among them, the oil cooling method allows oil to flow inside the motor, so that the heating parts in the motor (such as coils, cores, magnets, etc.) are in direct contact with the cooling medium (oil), thereby achieving a higher cooling effect. In an oil-cooled motor, the oil (lubricating oil) is made to flow inside the motor, thereby lubricating and cooling the motor at the same time. The lubricating oil (motor oil) of the motor is required to have electrical insulation properties.

[0003] In addition, the power systems of electric vehicles such as electric vehicles and hybrid vehicles, in addition to rechargeable batteries, also have power electronics devices (such as DC choppers, inverters, rectifiers, frequency converters, etc.) that control the charging and discharging of the batteries and perform power conversion and / or control. Power electronic machine devices have circuits that include power semiconductor elements (such as rectifier diodes, power transistors, thyristors, bidirectional thyristors (TRIAC)), etc. Since these elements that constitute the power system of electric vehicles also generate heat during driving, when the temperature becomes high, the efficiency decreases and the life is shortened, so cooling is required. When oil cooling is used to cool the battery and / or power electronic equipment, the oil used for the oil cooling is required to have electrical insulation properties.

[0004] Automobiles using electric motors as driving power sources generally have a transmission having a gear mechanism. Lubricating oil for lubricating the gear mechanism is compounded with one or more additives in order to obtain the lubricating performance required for lubricating the gears. [Prior art literature] [Patent Literature]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2013-133453 [Patent Document 2] Japanese Patent Application Publication No. 2009-235252 [Patent Document 3] Japanese Patent Application Publication No. 2006-257383 [Patent Document 4] International Publication No. 2019 / 129793 [Patent Document 5] International Publication No. 2018 / 190431 [Patent Document 6] International Publication No. 2016 / 136873 [Patent Document 7] Japanese Patent Application Publication No. 2018-070700 [Patent Document 8] Japanese Patent Application Publication No. 2018-053017 [Patent Document 9] International Publication No. 2004 / 069967 [Patent Document 10] International Publication No. 2013 / 136582 [Patent Document 11] Japanese Patent Application Publication No. 2006-117851 [Patent Document 12] International Publication No. 2010 / 032781 Summary of the invention [Problems to be solved by the invention]

[0006] The motor and the transmission are usually lubricated with different lubricants. If the motor and the transmission (gear mechanism) can be lubricated with the same lubricant, the lubricant circulation mechanism can be simplified. In addition, an electric drive module (drive module) that assembles the motor and the transmission (gear mechanism) as an integrated device (package) has recently been proposed. In the lubrication of such an electric drive module, from the perspective of miniaturization and lightness, it is expected that the motor and the transmission (gear mechanism) are lubricated with the same lubricant.

[0007] Among lubricating oil additives, additives that have the function of reducing frictional resistance (friction modifiers, hereinafter sometimes referred to as "FM") are important components for reducing energy loss caused by friction. Commonly used FMs can be classified into: organic molybdenum-based FMs containing molybdenum, and oily agent-based FMs (also called ashless FMs) that reduce friction by improving oiliness. In order to obtain the lubrication performance required for the lubrication of gears, it is advantageous to mix friction modifiers into lubricating oils. On the other hand, the friction reduction effect brought about by friction modifiers depends on the content of friction modifiers. In conventional lubricating oils containing friction modifiers, when the content of friction modifiers is increased in order to obtain the desired friction reduction effect, the performance is restricted due to the trade-off that the electrical insulation of the lubricating oil is greatly reduced. In addition, there is still room for improvement in fatigue resistance of conventional oily agent-based FMs.

[0008] The present invention is a lubricating oil composition containing an oiliness agent-based friction modifier, and an object of the present invention is to provide a lubricating oil composition having improved friction reduction performance and fatigue resistance while suppressing a decrease in electrical insulation properties.

Methods to solve the problem

[0009] The present invention includes the following embodiments [1] to

[14] .

[0010] [1] A lubricating oil composition comprising (A) a lubricating base oil comprising one or more mineral base oils or one or more synthetic base oils or a combination thereof, (B1) one or more first amide compounds and / or salts thereof, wherein the first amide compound is a monoamide of one or more linear or branched saturated or unsaturated monovalent fatty acids (a1) having 6 to 30 carbon atoms and one or more amine compounds (a2) having no ester bond, and the amine compound (a2) is an alkanolamine oligomer having a structure formed by dehydration condensation of one or more alkanolamines (a3) ​​represented by the following general formula (1) and having a degree of polymerization of 2 or more, (B2) one or more second amide compounds, wherein the second amide compounds have a structure in which the amino groups and one or more hydroxyl groups of one or more alkanolamines (a3) ​​represented by the following general formula (1) are acylated with the monobasic fatty acid (a1); (B3) at least one third amide compound, wherein the third amide compound is an amide of the alkanolamine (a3) ​​and the monovalent fatty acid (a1) and does not have an ester bond, (B4) at least one fourth amide compound and / or its salt, wherein the fourth amide compound has a structure in which at least one amino group and at least one hydroxyl group of the amine compound (a2) are acylated with the monovalent fatty acid (a1), The total content of the component (B1), the component (B2), the component (B3) and the component (B4) is 0.001 to 10.0% by mass based on the total amount of the composition, as calculated as the content of the compound in a state not forming a salt. And satisfies the following formula (eq1). M B2 / M B 1≧0.50…(eq1) (In formula (eq1), M B2 is the content of the component (B2) based on the total amount of the composition (unit: mass %), M B 1 is the content of the component (B1) based on the total amount of the composition in terms of the compound not forming a salt (unit: mass %).

[0011]

Chemical formula 1

[0012] [2] The lubricating oil composition according to [1], wherein the content of the component (B1) is 0.005 to 10.0% by mass, calculated as a content of the compound in a non-salt state, based on the total amount of the lubricating oil composition.

[0013] [3] The lubricating oil composition according to [1] or [2], which satisfies the following formula (eq2). M B2 / (M B 1+M B3 )≧0.100…(eq2) (In formula (eq2), M B 1 and M B2 As defined above, M B 3 is the content of the component (B3) based on the total amount of the composition (unit: mass %).

[0014] [4] The lubricating oil composition according to any one of [1] to [3], wherein the content of the component (B2) is 8.0% by mass or more, based on the total content of all acylated products of the monovalent fatty acid (a1) in the compound containing an alkanolamine structure in a non-salt state, and the hydroxyl group in the compound containing an alkanolamine structure may be etherified.

[0015] [5] The lubricating oil composition according to any one of [1] to [4], wherein the total content of all acylated products of the monobasic fatty acid (a1) in the compound containing an alkanolamine structure, calculated as a compound not forming a salt, is 0.001 to 10.0% by mass based on the total amount of the composition, and the hydroxyl group in the compound containing an alkanolamine structure may be etherified.

[0016] [6] The lubricating oil composition according to any one of [1] to [5], wherein the monovalent fatty acid contains one or more straight-chain fatty acids.

[0017] [7] The lubricating oil composition according to any one of [1] to [6], wherein the monovalent fatty acid contains one or more branched-chain fatty acids.

[0018] [8] The lubricating oil composition according to [7], wherein the branched fatty acid has a tertiary carbon or a quaternary carbon atom at the α-position, β-position or γ-position of the carbonyl carbon.

[0019] [9] The lubricating oil composition according to any one of [1] to [8], further comprising one or more additives selected from the group consisting of metallic detergents, ashless dispersants, phosphorus-containing antiwear agents, sulfur-containing extreme pressure agents, antioxidants and viscosity index improvers.

[0020]

[10] The lubricating oil composition according to any one of [1] to [9], wherein the kinematic viscosity at 40° C. is 4.0 to 50 mm 2 / s, The kinematic viscosity at 100°C is 1.0~6.9mm 2 / s.

[0021]

[11] The lubricating oil composition according to any one of [1] to

[10] , which is used for lubrication of gears.

[0022]

[12] The lubricating oil composition according to any one of [1] to

[11] , which is used for lubricating an electric motor or lubricating the electric motor and a transmission in a vehicle equipped with an electric motor.

[0023]

[13] A method for lubricating an electric motor, comprising supplying the lubricating oil composition according to any one of [1] to

[12] to the electric motor of a vehicle equipped with the electric motor.

[0024]

[14] A method for lubricating an electric motor and a transmission, comprising supplying the lubricating oil composition according to any one of [1] to

[12] to the electric motor and the transmission of a vehicle equipped with the electric motor and the transmission. [Effects of the invention]

[0025] The lubricating oil composition of the present invention is a lubricating oil composition containing an oiliness agent-based friction modifier, and can exhibit an enhanced friction reduction effect and fatigue resistance while suppressing a decrease in electrical insulation properties. DETAILED DESCRIPTION

[0026] The present invention is described in detail below. In addition, in this specification, unless otherwise specified, for numerical values ​​A and B, the expression "A to B" is equivalent to "above A and below B". In this expression, when only a unit is added to numerical value B, the unit is assumed to also apply to numerical value A. In this specification, unless otherwise specified, the words "or" and "or" are assumed to represent logical OR. In this specification, for elements E1 and E2, the expression "E1 and / or E2" is equivalent to "E1 or E2, or a combination thereof", and for N elements E1, ..., E i ,…,E N (N is an integer greater than 3.), "E1, ..., and / or E N " is the same as "E1, ..., or E i , ..., or EN is equivalent to “or a combination thereof” (where i is a variable taking all integer values that satisfy 1 < i < N). In addition, in this specification, “alkaline earth metal” is assumed to include magnesium as well.

[0027] In addition, in this specification, unless otherwise specified, the content of each element of calcium, magnesium, zinc, phosphorus, sulfur, boron, barium, and molybdenum in the oil is set to the value measured by inductively coupled plasma emission spectrometry (intensity ratio method (internal standard method)) according to JIS K0116. In addition, the content of nitrogen element in the oil is set to the value measured by chemiluminescence method according to JIS K2609. In addition, in this specification, “weight-average molecular weight” means the weight-average molecular weight converted to standard polystyrene measured by gel permeation chromatography (GPC). The measurement conditions of GPC are as follows. [GPC Measurement Conditions] Apparatus: ACQUITY (registered trademark) APC UV RI system manufactured by Waters Corporation Chromatographic columns: Two ACQUITY (registered trademark) APCXT900A columns (gel particle size 2.5 μm, column size (inner diameter × length) 4.6 mm × 150 mm) and one ACQUITY (registered trademark) APC XT200A column (gel particle size 2.5 μm, column size (inner diameter × length) 4.6 mm × 150 mm) manufactured by Waters Corporation are connected in series from the upstream side Column temperature: 40 °C Sample solution: Tetrahydrofuran solution with a sample concentration of 1.0 mass% Eluent: Tetrahydrofuran Solution injection volume: 20.0 μL Detection device: Differential refractive index detector Reference substance: 8 portions of standard polystyrene (Agilent EasiCal (registered trademark) PS-1 manufactured by Agilent Technologies) (molecular weights: 2698000, 597500, 290300, 133500, 70500, 30230, 9590, 2970) When the weight-average molecular weight measured based on the above conditions is less than 10000, the chromatographic column and the reference substance are changed to the following conditions for re-measurement. Chromatographic columns: One Waters Corporation ACQUITY (registered trademark) APC XT125A (gel particle size 2.5 μm, column size (inner diameter × length) 4.6 mm × 150 mm) and two Waters Corporation ACQUITY (registered trademark) APC XT45A (gel particle size 1.7 μm, column size (inner diameter × length) 4.6 mm × 150 mm) connected in series from the upstream side Reference material: 10 parts of standard polystyrene (Agilent EasiCal (registered trademark) PS-1 manufactured by Agilent Technologies) (molecular weight: 30230, 9590, 2970, 890, 786, 682, 578, 474, 370, 266)

[0028] <(A) Lubricant base oil> The lubricating oil composition of the present invention (hereinafter sometimes referred to as "lubricating oil composition" or "composition") comprises a base oil of lubricating viscosity (lubricating base oil) in a major amount and one or more additives other than the base oil. In the lubricating oil composition of the present invention, as the lubricating base oil, a lubricating base oil containing one or more mineral base oils or one or more synthetic base oils or a combination thereof can be used.

[0029] As the lubricating base oil (hereinafter sometimes referred to as "(A) component".), one or more mineral oil base oils or one or more synthetic base oils or mixed base oils thereof can be used. In one embodiment, as the lubricating base oil, a Class I base oil (hereinafter sometimes referred to as "API Class I base oil"), a Class II base oil (hereinafter sometimes referred to as "API Class II base oil"), a Class III base oil (hereinafter sometimes referred to as "API Class III base oil"), a Class IV base oil (hereinafter sometimes referred to as "API Class IV base oil") or a Class V base oil (hereinafter sometimes referred to as "API Class V base oil"), or mixed base oils thereof can be used. API Class I base oil is a mineral oil base oil having a sulfur content greater than 0.03% by mass and / or a saturated content less than 90% by mass, and a viscosity index of 80 or more and less than 120. API Class II base oil is a mineral oil base oil having a sulfur content less than 0.03% by mass, a saturated content greater than 90% by mass, and a viscosity index of 80 or more and less than 120. API Group III base oils are mineral oil-based base oils with a sulfur content of 0.03% by mass or less, a saturation content of 90% by mass or more, and a viscosity index of 120 or more. API Group IV base oils are poly-α-olefin base oils. API Group V base oils are base oils other than the above-mentioned Groups I to IV, and ester base oils can be cited as preferred examples thereof.

[0030] In one embodiment, as component (A), one or more API Group II base oils, one or more API Group III base oils, one or more API Group IV base oils, one or more API Group V base oils, or a combination thereof can be preferably used.

[0031] Examples of mineral oil-based base oils include lubricating oil fractions obtained by atmospheric distillation and / or vacuum distillation of crude oil, paraffinic base oils refined by one or a combination of two or more of the refining treatments selected from solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrofining, sulfuric acid cleaning, clay treatment, etc., normal paraffinic base oils, isoparaffinic base oils, and mixtures thereof, etc. API Group II base oils and Group III base oils are usually produced by a hydrocracking process.

[0032] From the viewpoint of further improving the viscosity-temperature characteristics and fuel economy of the composition, the %C of the mineral oil-based base oil is P It is preferably 60 or more, more preferably 65 or more. In addition, from the viewpoint of improving the solubility of the additive, it is preferably 99 or less, more preferably 95 or less, further preferably 94 or less. In one embodiment, it can be 60-99 or 60-95, 65-95, 65-94.

[0033] From the viewpoint of further improving the viscosity-temperature characteristics and fuel economy of the composition, the %C of the mineral oil-based base oil is A It is preferably 2 or less, more preferably 1 or less, further preferably 0.8 or less, and particularly preferably 0.5 or less.

[0034] From the viewpoint of improving the solubility of additives, the %C of mineral oil base oil is N It is preferably 1 or more, more preferably 4 or more, and from the viewpoint of further improving the viscosity-temperature characteristics and fuel economy of the composition, it is preferably 40 or less, more preferably 35 or less, and in one embodiment, it may be 1 to 40 or 4 to 35.

[0035] In this specification, %C P 、%C N and %C AThey refer to the percentage of paraffin carbon atoms relative to the total carbon atoms, the percentage of cycloalkane carbon atoms relative to the total carbon atoms, and the percentage of aromatic carbon atoms relative to the total carbon atoms, respectively, as determined by the method of ASTM D 3238-85 (ndM ring analysis). P 、%C N and %C A The preferred range of %C is based on the range of values ​​obtained by the above method. For example, even for a lubricating base oil containing no cycloparaffin, the %C N Values ​​greater than 0 can also be displayed.

[0036] From the viewpoint of improving the viscosity-temperature characteristics of the composition, the content of saturated fractions in the mineral oil-based base oil is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 99% by mass or more, based on the total amount of the base oil. In addition, in this specification, the saturated fraction refers to a value measured according to ASTM D 2007-93.

[0037] Based on the total amount of base oil, the content of aromatic components in the mineral oil base oil is preferably 0 to 10% by mass, more preferably 0 to 5% by mass, and particularly preferably 0 to 1% by mass. In one embodiment, it can be 0.1% by mass or more. By making the content of aromatic components below the above upper limit, in addition to improving the low-temperature viscosity characteristics and viscosity-temperature characteristics in the new oil state, it can also further improve fuel economy while reducing the evaporation loss of the lubricating oil and reducing the consumption of the lubricating oil. In addition, when additives are blended in the lubricating base oil, the role of the additive can be effectively exerted. In addition, the lubricating base oil may not contain aromatic components, but by making the content of aromatic components above the above lower limit, the solubility of the additive can be improved.

[0038] In addition, in this specification, the aromatic fraction refers to the value measured according to ASTM D 2007-93. The aromatic fraction generally includes anthracene, phenanthrene and their alkylated products in addition to alkylbenzenes and alkylnaphthalenes, and further includes compounds having four or more benzene rings condensed, pyridines, quinolines, phenols, naphthols and other aromatic compounds having heteroatoms.

[0039] Examples of API Group IV base oils include oligomers and cooligomers of α-olefins having 2 to 32 carbon atoms, preferably 6 to 16 carbon atoms, such as ethylene-propylene copolymers, polybutene, 1-octene oligomers, 1-decene oligomers, and hydrogenated products thereof, and hydrogenated products thereof.

[0040] As preferred examples of API Class V base oils, various ester base oils can be cited. Examples of ester base oils include monoester base oils (e.g., butyl stearate, octyl laurate, oleic acid-2-ethylhexyl ester, etc.); diester base oils (e.g., di(tridecyl glutarate), di-2-ethylhexyl adipate, diisodecyl adipate, di(tridecyl adipate), di-2-ethylhexyl sebacate, etc.); polycarboxylic acid ester base oils (e.g., trimellitic acid esters, etc.); polyol ester base oils (e.g., trimethylolpropane octanoate, trimethylolpropane nonanoate, pentaerythritol-2-ethylhexanoate, pentaerythritol nonanoate, etc.). Other examples of API Class V base oils include aromatic synthetic base oils such as alkylbenzenes, alkylnaphthalenes, polyoxyalkylene glycols, dialkyldiphenyl ethers, and polyphenylene ethers.

[0041] From the viewpoint of improving energy saving and low temperature viscosity characteristics of the lubricating oil composition, the kinematic viscosity of the lubricating oil base oil (all base oils) at 40°C is 40 mm 2 / s or less, preferably 30mm 2 / s or less, more preferably 20mm 2 / s or less, and preferably 2.0 mm from the viewpoint of improving abrasion resistance and galling resistance. 2 / s or above or 5.0mm 2 / s or more, 8.0mm 2 / s or more, and in one embodiment, may be 2.0 to 40 mm 2 / s or 5.0~30mm 2 / s, 8.0~20mm 2 In addition, in this specification, "40 degreeC kinematic viscosity" means the kinematic viscosity at 40 degreeC measured using the automatic viscometer (trade name "CAV-2100", manufactured by Cannon Instrument Co., Ltd.) as a measuring device according to JIS K 2283-2000.

[0042] From the viewpoint of further improving the energy saving performance and the low temperature viscosity characteristics of the lubricating oil composition, the kinematic viscosity of the lubricating oil base oil (all base oils) at 100° C. is preferably 10.0 mm 2 / s or less, more preferably 7.0 mm 2 / s or less, more preferably 4.0 mm 2 / s or less, and preferably 0.8 mm from the viewpoint of improving abrasion resistance and pick resistance. 2 / s or above or 1.2mm 2 / s or more, 1.4mm 2 / s or more, 1.6mm 2 / s or more, and in one embodiment, may be 0.8 to 10.0 mm 2 / s, 1.2~10.0mm 2 / s or 1.4~7.0mm 2 / s, 1.6~4.0mm 2 In addition, in this specification, "kinematic viscosity at 100° C." means the kinematic viscosity at 100° C. measured using an automatic viscometer (trade name "CAV-2100", manufactured by Cannon Instrument Co., Ltd.) as a measuring device in accordance with JIS K 2283-2000.

[0043] From the viewpoint of improving the viscosity-temperature characteristics of the composition and further improving fuel economy and wear resistance, the viscosity index of the lubricating base oil (total base oil) is preferably 100 or more, more preferably 105 or more, further preferably 110 or more, particularly preferably 115 or more, and most preferably 120 or more. In this specification, the viscosity index refers to a viscosity index measured using an automatic viscometer (trade name "CAV-2100", manufactured by Cannon Instrument Co., Ltd.) as a measuring device in accordance with JIS K 2283-2000.

[0044] From the viewpoint of the low-temperature fluidity of the entire lubricating oil composition, the pour point of the lubricating base oil (all base oils) is preferably -10°C or lower, more preferably -12.5°C or lower, further preferably -15°C or lower, particularly preferably -17.5°C or lower, and most preferably -20.0°C or lower. In this specification, the pour point means the pour point measured in accordance with JIS K 2269-1987.

[0045] The content of sulfur in the base oil is related to the content of sulfur in its raw material. For example, when using a substantially sulfur-free raw material such as a synthetic wax component obtained by a Fischer-Tropsch reaction, a substantially sulfur-free base oil can be obtained. In addition, when using sulfur-containing raw materials such as slack wax obtained in the refining process of the base oil or microwax obtained in the refined wax process, the sulfur content in the obtained base oil is usually more than 100 mass ppm. The content of sulfur in the lubricating base oil (all base oils) is usually less than 0.03 mass %, and from the viewpoint of oxidation stability, it is preferably less than 0.01 mass %. In addition, in this specification, the content of sulfur in the base oil refers to: the sulfur amount measured according to JIS K 2541-2003.

[0046] The lubricating oil base oil may be composed of a single base oil component or may contain a plurality of base oil components. In a preferred embodiment, the kinematic viscosity of the base oil as a whole (the entire base oil) at 40° C. may be 40 mm 2 / s or less.

[0047] In one embodiment, the lubricating base oil may contain 80-100 mass %, 90-100 mass %, 90-99 mass %, 95-99 mass % of one or more API Group II base oils, one or more API Group III base oils, one or more API Group IV base oils, or one or more API Group V base oils, or a combination thereof, based on the total amount of the base oil. The lubricating base oil may or may not contain an API Group V base oil, but in one embodiment, from the viewpoint of improving oxidation stability, the content of the one or more API Group V base oils in the lubricating base oil is preferably 0-50 mass % or 0-45 mass % based on the total amount of the base oil, and from the viewpoint of improving fatigue resistance, it may be 1-50 mass % or 1-45 mass %. The lubricating base oil may or may not contain an API Group IV base oil. However, in one embodiment, the content of one or more API Group IV base oils in the lubricating base oil may be 0 to 70 mass %, or 0 to 65 mass %, 1 to 70 mass %, or 1 to 65 mass %, based on the total amount of the base oil.

[0048] The content of the lubricating base oil (total base oil) in the lubricating oil composition is 60% by mass or more, preferably 60 to 98.5% by mass, more preferably 70 to 98.5% by mass, and in one embodiment, 75 to 97% by mass, based on the total amount of the lubricating oil composition.

[0049] <(B1) First Amide Compound and / or Salt thereof> The lubricating oil composition of the present invention contains (B1) one or more first amide compounds and / or salts thereof (hereinafter sometimes referred to as "(B1) component" or "component (B1)"), wherein the first amide compound is a monoamide of one or more linear or branched saturated or unsaturated monovalent fatty acids (a1) having 6 to 30 carbon atoms and having no ester bond and one or more amine compounds (a2), wherein the amine compound (a2) is an alkanolamine oligomer having a structure formed by dehydration condensation of one or more alkanolamines (a3) ​​represented by the following general formula (1) and having a polymerization degree of 2 or more.

[0050]

Chemical formula 2

[0051] Fatty acid (a1) can be one kind of fatty acid or a combination of two or more kinds of fatty acids. Fatty acid (a1) can be a saturated fatty acid or an unsaturated fatty acid. In addition, fatty acid (a1) can be a straight-chain fatty acid or a branched-chain fatty acid. In a preferred embodiment, fatty acid (a1) can be a branched-chain fatty acid. Examples of straight-chain saturated fatty acids include caproic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, eicosanoic acid, heneicosanoic acid and docosanoic acid, tetracosanoic acid, hexacosanoic acid, octacosanoic acid, triacontanoic acid, etc., and examples of branched-chain saturated fatty acids include their branched-chain isomers. Examples of straight-chain unsaturated fatty acids include hexenoic acid, heptenoic acid, octenoic acid, nonenoic acid, decenoic acid, undecenoic acid, dodecenoic acid, tridecenoic acid, tetradecenoic acid, pentadecenoic acid, hexadecenoic acid, heptadecenoic acid, octadecenoic acid, nonadecenoic acid, eicosenoic acid, heneicosenoic acid, docosenoic acid, tetracosenoic acid, hexacosenoic acid, octacosenoic acid, triacontadecenoic acid, and examples of branched unsaturated fatty acids include their branched isomers. In addition, there is no particular restriction on the configuration of the C=C double bond in the unsaturated fatty acid. The number of C=C double bonds in the unsaturated fatty acid may be 1 (i.e., monoenoic acid), 2 (i.e., dienoic acid), 3 (i.e., trienoic acid), or 4 (i.e., tetraenoic acid) or more. In addition, the C=C double bond in the unsaturated fatty acid may be a cis-type (Z-type) or a trans-type (E-type), and a cis-type (Z-type) C=C double bond and a trans-type (E-type) C=C double bond may coexist between different molecules or in the same molecule. For example, fatty acids derived from hydrogenated natural oils and fats may contain, in addition to saturated fatty acids produced by hydrogenation, unsaturated fatty acids having a cis-type C=C double bond and unsaturated fatty acids having a trans-type C=C double bond derived from a side reaction of the hydrogenation reaction. For example, as specific examples of unsaturated fatty acids having 18 carbon atoms, various similar compounds having different numbers, configurations and / or geometrical isomers of C=C double bonds, such as oleic acid (cis-9-octadecenoic acid), vaccenic acid (11-octadecenoic acid), linoleic acid (cis, cis-9,12-octadecadienoic acid), linolenic acid (9,12,15-octadecatrienoic acid, 6,9,12-octadecatrienoic acid), and eleostearic acid (9,11,13-octadecatrienoic acid) can be cited. Various similar compounds having different numbers, configurations and / or geometrical isomers of C=C double bonds can also be cited for unsaturated fatty acids having other carbon atoms.

[0052] From the viewpoint of improving the friction reduction effect in lubrication of gears, etc., the number of carbon atoms in the fatty acid (a1) is 6 or more, preferably 8 or more, 10 or more, or 12 or more. From the same viewpoint, it is 30 or less, preferably 24 or less, 22 or less, 20 or less, or 18 or less. In one embodiment, it can be 6 to 30, or 8 to 24, 8 to 22, 10 to 22, 12 to 20, or 12 to 18. In one embodiment, the fatty acid (a1) can be one or more straight-chain fatty acids. Preferred examples of straight-chain fatty acids include caproic acid, heptanoic acid, octanoic acid, nonanoic acid, capric acid, lauric acid, myristic acid, myristic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, vaccenic acid, elaidic acid, linoleic acid, linolenic acid, eleostearic acid, stearidonic acid, arachidic acid, gadoleic acid, eicosenoic acid, eicosapentaenoic acid, behenic acid, erucic acid, clupanodonic acid, docosahexaenoic acid, lignoceric acid, nisinic acid, nervonic acid, cerotic acid, montanic acid, melissic acid, and mixtures thereof. As a mixture having two or more fatty acids, fatty acids derived from natural fats or hydrogenated natural fats may also be used. Examples of fatty acids derived from natural oils and fats include coconut oil fatty acids, palm kernel oil fatty acids, palm oil fatty acids, tung oil fatty acids, tall oil fatty acids, corn oil fatty acids, rapeseed oil fatty acids, olive oil fatty acids, sesame oil fatty acids, soybean oil fatty acids, rice bran oil fatty acids, sunflower oil fatty acids, castor oil fatty acids, linseed oil fatty acids, fish oil fatty acids, tallow fatty acids, hydrogenated products thereof, and mixtures thereof. These fatty acids derived from natural oils and fats are usually mixtures containing two or more fatty acids having 6 to 24 carbon atoms. In one embodiment, the fatty acid (a1) may be one or more branched fatty acids. In one embodiment, the branched fatty acid preferably has a tertiary carbon or a quaternary carbon atom (i.e., a branched chain) at the α, β, or γ position of the carbonyl carbon, preferably has a tertiary carbon or a quaternary carbon atom at the α or β position of the carbonyl carbon, and particularly preferably has a tertiary carbon or a quaternary carbon atom at the α position of the carbonyl carbon. As a preferred example of such a branched fatty acid, a branched fatty acid represented by the following general formula (2) may be mentioned.

[0053]

Chemical formula 3

[0054]

Chemical formula 4

[0055] The amine compound (a2) is an alkanolamine oligomer having a polymerization degree of 2 or more and having a structure obtained by dehydration condensation of one or more alkanolamines (a3) ​​represented by the following general formula (1).

[0056]

Chemical formula 5

[0057] In a preferred embodiment, the alkylene group R 1 The radical may be ethane-1,2-diyl, propane-1,3-diyl, propane-1,2-diyl, butane-1,2-diyl, butane-1,4-diyl or butane-2,3-diyl, or a combination thereof.

[0058] The alkanolamine represented by the general formula (1) is a monoalkanolamine when n=1 and a dialkanolamine when n=2. 1In the case of an asymmetric branched alkylene group, that is, the side chains bonded to the two free atomic valences are different alkylene groups (e.g., propane-1,2-diyl, butane-2,3-diyl, pentane-2,3-diyl, etc.), any one of the two free atomic valences may be bonded to the nitrogen atom. For example, in the reaction of propylene oxide and ammonia, the reaction route to form a propanolamine structure in which the 1-position of propylene-1,2-diyl is bonded to the nitrogen atom (i.e., the nitrogen atom is bonded to the 2-hydroxypropyl group) competes with the reaction route to form a propanolamine structure in which the 2-position of propylene-1,2-diyl is bonded to the nitrogen atom (i.e., the nitrogen atom is bonded to the 1-hydroxypropane-2-yl group), and a mixture of the two products may be formed. In the general formula (1), in the dialkanolamine with n=2, the two R 1 They can be the same or different. 1 When the two R 1 The directions of the two R 1 In dipropanolamine, which is propane-1,2-diyl, the two HO-R 1 -yl may be both 2-hydroxypropyl, or both 1-hydroxypropane-2-yl, or one may be 2-hydroxypropyl and the other 1-hydroxypropane-2-yl. When dipropanolamine is produced by the reaction of propylene oxide and ammonia, these compounds may be generated simultaneously to form a mixture. The one or more alkanolamines (a3) ​​represented by the general formula (1) may be one or more monoalkanolamines, one or more dialkanolamines, or a combination of one or more monoalkanolamines and one or more dialkanolamines, but one or more dialkanolamines are particularly preferred.

[0059] In component (i), the monovalent fatty acid (a1) and the amine compound (a2) forming a monoamide are alkanolamine oligomers having a structure formed by dehydration condensation of one or more alkanolamines (a3) ​​represented by the general formula (1), and the degree of polymerization is 2 or more. For example, the following general formula (4) represents a reaction in which an alkanolamine dimer (a2-dd) having a degree of polymerization of 2 is generated by a dehydration condensation reaction of two molecules of dialkanolamine (a3d). In addition, for example, the following general formula (5) represents a reaction in which an alkanolamine dimer (a2-mm) having a degree of polymerization of 2 is generated by a dehydration condensation reaction of two molecules of monoalkanolamine (a3m). In addition, for example, the following general formula (6) represents a reaction in which an alkanolamine dimer (a2-2dm or a2-2md) having a degree of polymerization of 2 is generated by a dehydration condensation reaction of one molecule of dialkanolamine (a3d) and one molecule of monoalkanolamine (a3m). As shown in the general formula (6), in the dehydration condensation reaction of dialkanolamine and monoalkanolamine, the product may contain structural isomers. Which structural isomer is generated depends on which molecule's hydroxyl group is detached.

[0060]

Chemical formula 6

[0061]

Chemical formula 7

[0062]

Chemical formula 8

[0063]

Chemical formula 9

[0064]

Chemical formula 10

[0065]

Chemical formula 11

[0066]

Chemical formula 12

[0067]

Chemical formula 13

[0068] The degree of polymerization of the amine compound (a2), i.e., the alkanolamine oligomer, is 2 or more, preferably 2 to 15 or 2 to 10, and in one embodiment, may be 2 to 4 or 2 to 3. The alkanolamine oligomer (a2) may have a single degree of polymerization, or may be a combination of oligomers having a plurality of different degrees of polymerization. In one embodiment, the alkanolamine oligomer (a2) may be a combination of oligomers having a plurality of continuous different degrees of polymerization. In this specification, a certain oligomer is "a combination of oligomers having a plurality of continuous different degrees of polymerization" means: the minimum and maximum values ​​of the degree of polymerization of the oligomer are set to d min and d MAX When the oligomer contains d min Above, d MAX Oligomers with all the following degrees of polymerization.

[0069] The first amide compound is a monoamide of one or more monobasic fatty acids (a1) and one or more amine compounds (a2), and is a compound without an ester bond. Component (B1) is the first amide compound and / or its salt. Since the first amide compound has one or more amine nitrogen atoms that are not acylated, it can form a salt with an acid. The salt of the first amide compound can be a salt of the first amide compound and an organic acid (organic acid salt), or a salt of the first amide compound and an inorganic acid (inorganic acid salt), or a combination of one or more organic acid salts and one or more inorganic acid salts. The organic acid salt can be one organic acid salt or a combination of two or more organic acid salts. The inorganic acid salt can be one inorganic acid salt or a combination of two or more inorganic acid salts. In addition, as described below, the organic acid constituting the organic acid salt can also be the above-mentioned monobasic fatty acid (a1).

[0070] Examples of inorganic acids that form inorganic acid salts with the first amide compound include hydrogen halides such as hydrogen fluoride, hydrogen chloride, hydrogen bromide, and hydrogen iodide; halogen oxygen acids such as hypochlorous acid, chlorous acid, chloric acid, perchloric acid, hypobromous acid, bromous acid, bromic acid, perbromic acid, hypoiodine acid, iodous acid, iodic acid, periodic acid; nitric acid, nitrous acid, sulfuric acid, sulfurous acid, phosphoric acid (an oxygen acid of phosphorus in which the apparent oxidation number of the phosphorus atom is +V, which may be orthophosphoric acid or condensed phosphoric acid such as pyrophosphoric acid and polyphosphoric acid), phosphorous acid, boric acid (an oxygen acid of boron in which the apparent oxidation number of the boron atom is +III, which may be orthoboric acid or condensed boric acid such as tetraboric acid and metaboric acid), and carbonic acid; and inorganic protonic acids (bronsted acid) such as cyanic acid.

[0071] Examples of organic acids that form organic acid salts with the first amide compound include organic protonic acids such as carboxylic acids, organic sulfonic acids, organic phosphonic acids and their monoesters, organic boric acids and their monoesters, sulfuric acid monoesters, phosphoric acid monoesters, phosphoric acid diesters, phosphite monoesters, phosphorous acid diesters, boric acid monoesters, boric acid diesters, and substituted or unsubstituted phenols.

[0072] Examples of the carboxylic acid that forms a salt with the first amide compound include aliphatic carboxylic acids and aromatic carboxylic acids. Examples of aliphatic carboxylic acids include monovalent fatty acids having 1 to 5 carbon atoms, monovalent fatty acids having 6 to 30 carbon atoms, divalent aliphatic carboxylic acids having 2 to 10 carbon atoms and monoesters thereof, and aliphatic hydroxy acids. Examples of the monovalent fatty acid having 1 to 5 carbon atoms include formic acid, acetic acid, propionic acid, butyric acid, and valeric acid. The monovalent fatty acid having 2 to 5 carbon atoms is preferred. Examples of the monovalent fatty acid having 6 to 30 carbon atoms include the various monovalent fatty acids described above with respect to the monovalent fatty acid (a1). Examples of dibasic aliphatic dicarboxylic acids having 2 to 10 carbon atoms include oxalic acid, malonic acid, succinic acid, fumaric acid, maleic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, etc. Examples of monoesters thereof include monoesters of the dibasic aliphatic dicarboxylic acids with alcohols such as methanol, ethanol, propanol, isopropanol, butanol, pentanol, hexanol, heptanol, octanol, 2-ethylhexanol, nonanol, decanol, undecanol, dodecanol, and for example, with alkanols having 1 to 12, 1 to 10, or 1 to 8 carbon atoms. Examples of aliphatic hydroxy acids include aliphatic hydroxy acids having 2 to 18 carbon atoms, such as glycolic acid, lactic acid, malonic acid, glyceric acid, hydroxybutyric acid, malic acid, tartaric acid, citramalic acid, citric acid, isocitric acid, leucine, mevalonic acid, pantoic acid, ricinolic acid, ricinelaidic acid, quinic acid, and shikimic acid. Other examples of the aliphatic carboxylic acid include halogenated (for example, fluorinated) aliphatic carboxylic acids such as trifluoroacetic acid, 3,3,3-trifluoropropionic acid, and 4,4,4-trifluorobutyric acid. Examples of the aromatic carboxylic acid include aromatic monocarboxylic acids, aromatic dicarboxylic acids and monoesters thereof, aromatic hydroxy acids, and aromatic polycarboxylic acids. Examples of the aromatic monocarboxylic acid include compounds having 7 to 10 carbon atoms, such as benzoic acid, o-, m- or p-toluic acid, phenylacetic acid, and cinnamic acid. Examples of aromatic dicarboxylic acids include phthalic acid, isophthalic acid, terephthalic acid, etc. Examples of monoesters thereof include monoesters of the aromatic dicarboxylic acids and the monoesters of the divalent aliphatic dicarboxylic acids in the various alcohols described above. Examples of aromatic hydroxy acids include salicylic acid, (m- or p-)hydroxybenzoic acid, (o-, m- or p-)hydroxymethylbenzoic acid, vanillic acid, syringic acid, (2,3-, 2,4-, 2,5-, 2,6-, 3,4- or 3,5-)dihydroxybenzoic acid, orsellinic acid, gallic acid, mandelic acid, hydroxydiphenylacetic acid (benzyl alcoholic acid), atrolactic acid, phloretic acid, (o-, m- or p-)hydroxycinnamic acid, (2,3-, 2,4-, 2,5-, 2,6-, 3,4- or 3,5-)dihydroxycinnamic acid, ferulic acid, sinapic acid, and the like, for example, compounds having 7 to 14 carbon atoms. Examples of the aromatic polycarboxylic acid include compounds having a structure in which 3 to 6 hydrogen atoms on a benzene ring are substituted with carboxyl groups, such as trimellitic acid and mellitic acid.

[0073] Examples of the organic sulfonic acid include compounds represented by the following general formula (14).

[0074]

Chemical formula 14

[0075] Examples of the organic phosphonic acid include compounds represented by the following general formula (15).

[0076]

Chemical formula 15

[0077] Examples of organic boronic acids include compounds represented by the following general formula (16).

[0078]

Chemical formula 16

[0079] Examples of sulfuric acid monoesters, phosphoric acid monoesters, phosphorous acid monoesters and boric acid monoesters include monoesters of sulfuric acid, orthophosphoric acid, phosphorous acid or orthoboric acid with the monoesters of dibasic aliphatic dicarboxylic acids in the various alcohols described above. Examples of phosphoric acid diesters and boric acid diesters include monoesters of orthophosphoric acid or orthoboric acid with the various alcohols described above with respect to the monoesters of divalent aliphatic dicarboxylic acids.

[0080] Preferred examples of substituted phenols include substituted phenols having a pKa smaller than that of unsubstituted phenols. Such substituted phenols generally have one or more substituents on the aromatic ring as electron-withdrawing groups. Examples of such electron-withdrawing groups include acyl groups such as acetyl, formyl, carboxyl, alkoxycarbonyl, nitro, cyano, halogen (e.g., fluoro, chloro, bromo, and iodo) and the like. Examples of alcohols corresponding to the alkoxy groups of the alkoxycarbonyl groups include the various alcohols described above with respect to divalent aliphatic dicarboxylic acids. Examples of such substituted phenols include acetylphenol, formylphenol, carboxylphenol, methoxycarbonylphenol, ethoxycarbonylphenol, nitrophenol, cyanophenol, fluorophenol, chlorophenol, bromophenol, iodophenol and the like. The number of carbon atoms in the substituted phenol may preferably be 6 to 13, 6 to 11, or 6 to 9.

[0081] From the viewpoint of further improving the friction reduction performance while suppressing the reduction of electrical insulation, especially the friction reduction performance in the mixed lubrication region such as the lubrication condition of gears, and from the viewpoint of further improving fatigue resistance, the content of component (B1) in the lubricating oil composition is preferably 0.001 mass % or more, 0.005 mass % or more, 0.010 mass % or more, 0.050 mass % or more, based on the total amount of the lubricating oil composition, in terms of the compound in a state not forming a salt. From the same viewpoint, it is preferably 10.0 mass % or less, 5.0 mass % or less, 3.0 mass % or less, 1.00 mass % or less, and in one embodiment, it can be 0.001 to 10.0 mass %, 0.005 to 10.0 mass %, 0.010 to 5.0 mass %, 0.050 to 3.0 mass %, 0.050 to 1.00 mass %. The first amide compound has at least one amino group that can form a salt. In the present specification, the content of component (B1) "in terms of the compound in a state where no salt is formed" means the content in terms of the first amide compound. That is, when the first amide compound does not form a salt at all, the content thereof is the content itself, and when all or part of the first amide compound forms a salt with an acid, the content is the content in terms of the mass in a state where no acid is used for neutralization.

[0082] <(B2) Second Amide Compound> In one embodiment, the lubricating oil composition of the present invention may further contain (B2) one or more second amide compounds (hereinafter sometimes referred to as "(B2) component" or "component (B2)"), wherein the second amide compound has a structure in which the amino group and one or more hydroxyl groups of one or more alkanolamines (a3) ​​represented by the general formula (1) are acylated with the monovalent fatty acid (a1). Component (B2) has a structure represented by the following general formula (17a), (17b) or (17c). General formulas (17a) and (17b) represent structures corresponding to dialkanolamines, and general formula (17c) represents a structure corresponding to monoalkanolamines. In a preferred embodiment, component (B2) has a structure in which the amino group and one or more hydroxyl groups of one or more dialkanolamines represented by the general formula (1) are acylated with the monovalent fatty acid (a1), and its structure is represented by general formula (17a) or (17b).

[0083]

Chemical formula 17

[0084] The lubricating oil composition may or may not contain the component (B2). In one embodiment, from the viewpoint of improving storage stability, further suppressing the decrease in electrical insulation, and further improving fatigue resistance, the content of the component (B2) in the lubricating oil composition is preferably 0.001% by mass or more, 0.005% by mass or more, 0.010% by mass or more, or 0.050% by mass or more based on the total amount of the composition. Furthermore, from the viewpoint of further suppressing the decrease in electrical insulation, further improving friction reduction performance, especially friction reduction performance in a mixed lubrication region such as lubrication conditions of gears, and further improving fatigue resistance, the content is preferably 10.0% by mass or less, 5.0% by mass or less, or 3.0% by mass or less based on the total amount of the composition. In one embodiment, it may be 0.001 to 10.0% by mass, 0.005 to 5.0% by mass, 0.010 to 5.0% by mass, 0.010 to 3.0% by mass, or 0.050 to 3.0% by mass.

[0085] In one embodiment, from the viewpoint of further improving storage stability and friction reduction performance, in particular, from the viewpoint of further improving friction reduction performance in a mixed lubrication region such as lubrication conditions of gears, and from the viewpoint of further improving fatigue resistance, the total content of components (B1) and (B2) in the lubricating oil composition is preferably 0.001% by mass or more, 0.005% by mass or more, 0.010% by mass or more, or 0.050% by mass or more, based on the total amount of the composition, as calculated as the content of the compounds in a state not forming a salt. Furthermore, from the viewpoint of ease of production and from the viewpoint of further suppressing a decrease in electrical insulation, it is preferably 10.0% by mass or less, 5.0% by mass or less, or 3.0% by mass or less. In one embodiment, it may be 0.001 to 10.0% by mass, 0.005 to 5.0% by mass, 0.010 to 5.0% by mass, 0.01 to 3.0% by mass, or 0.050 to 3.0% by mass.

[0086] <(B3) The third amide compound> In one embodiment, the lubricating oil composition may further contain (B3) a third amide compound (hereinafter sometimes referred to as "(B3) component" or "component (B3)"), wherein the third amide compound is an amide of one or more alkanolamines (a3) ​​represented by the general formula (1) and the monobasic fatty acid (a1) and does not have an ester bond. The third amide compound has a structure represented by the following general formula (18a) or (18b). The general formula (18a) represents the structure corresponding to a dialkanolamine, and the general formula (18b) represents the structure corresponding to a monoalkanolamine. In a preferred embodiment, the component (B3) has a structure in which an amino group and one or more hydroxyl groups of one or more dialkanolamines represented by the general formula (1) are acylated with the monobasic fatty acid (a1), and its structure is represented by the general formula (18a).

[0087]

Chemical formula 18

[0088] <(B4) Fourth Amide Compound and / or Salt thereof> In one embodiment, the lubricating oil composition may further contain (B4) a fourth amide compound and / or a salt thereof (hereinafter sometimes referred to as "(B4) component" or "component (B4)".), wherein the fourth amide compound has a structure in which one or more amino groups and one or more hydroxyl groups of the above-mentioned amine compound (a2) are acylated with the above-mentioned monobasic fatty acid (a1). The fourth amide compound is different from the first amide compound in that it has not only an amide bond but also an ester bond. The fourth amide compound may have one or more amino groups that can form a salt. Examples of acids that form a salt with the fourth amide compound include the various acids described above with respect to (B1).

[0089] The lubricating oil composition may or may not contain (B3). In addition, the lubricating oil composition may or may not contain the component (B4). In one embodiment, from the viewpoint of further suppressing the reduction of electrical insulation and from the viewpoint of further improving fatigue resistance, the total content of the components (B3) and (B4) in the lubricating oil composition is preferably 3.0% by mass or less, or may be 1.00% by mass or less, based on the total amount of the composition, in terms of the content of the compound in a state of not forming a salt. In addition, from the viewpoint of ease of production, based on the total amount of the composition, it is preferably 0.010% by mass or more or 0.100% by mass or more in the above conversion, and in one embodiment, it may be 0.010 to 3.0% by mass or 0.100 to 1.00% by mass. In the present specification, the content of component (B4) "in terms of the compound in a state where no salt is formed" means the content in terms of the fourth amide compound. That is, when the fourth amide compound does not form a salt at all, the content thereof is the content itself, and when all or part of the fourth amide compound forms a salt with an acid, the content is the content in terms of the mass in a state where no acid is used for neutralization.

[0090] In one embodiment, from the viewpoint of improving storage stability, further suppressing a decrease in electrical insulation while improving friction reduction performance, in particular, friction reduction performance under mixed lubrication conditions, and further improving fatigue resistance, the content of component (B2) in the lubricating oil composition is preferably 8.0% by mass or more, 10.0% by mass or more, or 12.0% by mass or more, based on the total content of all acylated products of the monovalent fatty acid (a1) in the compound containing an alkanolamine structure in a state in which the compounds are not in a salt state. The hydroxyl group in the compound containing an alkanolamine structure may also be etherified, and from the viewpoint of further suppressing a decrease in electrical insulation and further improving fatigue resistance, it is preferably 90% by mass or less, 80% by mass or less, or 75% by mass or less, and in one embodiment, it may be 8.0 to 90% by mass, 10.0 to 80% by mass, or 12.0 to 75% by mass.

[0091] In one embodiment, from the viewpoint of ease of production and further improvement of storage stability, the total content of components (B2) and (B3) in the lubricating oil composition is preferably 20% by mass or more, or 50% by mass or more, greater than 85% by mass, or 86% by mass or more, based on the total content of all acylated products of the monovalent fatty acid (a1) in the compound containing an alkanolamine structure in a state in which the compound does not form a salt, and the hydroxyl group in the compound containing an alkanolamine structure may also be etherified. From the viewpoint of further suppressing a decrease in electrical insulation, it is preferably 99% by mass or less, or may be 96% by mass or less. In one embodiment, it may be 20 to 99% by mass, or 50 to 99% by mass, greater than 85% by mass and 99% by mass or less, or 86 to 99% by mass.

[0092] In the present specification, the term "compounds containing alkanolamine structures" as used herein refers to "all acylated products of the monovalent fatty acid (a1) containing alkanolamine structures, wherein the hydroxyl groups in the compounds containing alkanolamine structures may also be etherified". This term also includes any alkanolamine structures, i.e., compounds containing HO-R 14 -NR 15 R 16 Structure (R 14 represents any alkylene group; R 15 and R 16 Each independently represents a hydrogen atom or an arbitrary organic group, R 15 and R16 The term "hydroxyl groups may also be etherified" in "alkanolamine structure" means that the alkanolamine structure (HO-R 14 -NR 15 R 16 The hydroxyl (-OH) group of the alkanolamine structure) can also be converted into an ether bond. As an example of a "hydroxyl group etherified alkanolamine structure", there can be cited a structure in which the hydroxyl group of the alkanolamine is converted into an ether bond by intermolecular or intramolecular dehydration condensation. In order for the alkanolamine to form an ether bond by intramolecular dehydration condensation, more than two hydroxyl groups need to be present in a single molecule, and for example, dialkanolamine satisfies this condition. The formation of an ether bond by the alkanolamine based on the intramolecular dehydration condensation reaction is a cyclization reaction, which can form an aza-oxacycloalkane skeleton (for example, a morpholine skeleton, etc.). Such an intramolecular dehydration cyclization reaction will be described in detail below. In addition, the "all acylated products of the above-mentioned monobasic fatty acid (a1)" is a concept that also includes any acylated product of the above-mentioned monobasic fatty acid (a1), for example, it can be an amide of the fatty acid (a1), it can also be an ester of the fatty acid (a1), and it can also be a compound acylated by the fatty acid (a1) at multiple locations in one molecule. In addition, the "total content of the compound converted to a state in which a salt is not formed" can be calculated by the following method: the content of the compound that does not form a salt and the content of the compound that forms a salt in a state in which a salt is not formed (for example, for a compound in which all or part of the unacylated amino group is neutralized with an acid, the content is converted to the mass in a state in which the compound is not neutralized with an acid) are respectively added up.

[0093] (manufacture) The amine compound (a2), i.e., an alkanolamine oligomer, can be produced, for example, by dehydration condensation of one or more alkanolamines (a3). The amine compound (a2) can be an oligomer having a single degree of polymerization, or a combination of two or more oligomers having different degrees of polymerization (e.g., a combination of a plurality of oligomers having consecutive different degrees of polymerization). In one embodiment, component (B1) can be manufactured by the dehydration condensation reaction of fatty acid (a1) and amine compound (a2). Such dehydration condensation reaction, for example, can be carried out by the following method: fatty acid (a1) and amine compound (a2) are in an organic solvent (such as toluene, xylene, isopropyl benzene, methyl isopropyl (cymene), etc.) that forms an azeotropic mixture with water, in the presence of an acid catalyst (such as sulfuric acid, trifluoroacetic acid, etc.) or a base catalyst (such as sodium carbonate, sodium hydroxide, potassium hydroxide, sodium acetate, sodium phosphate, etc.) or in the absence of a catalyst, and the water generated by the condensation reaction is removed by azeotropic removal. In addition, under catalyst-free conditions, fatty acid (a1) itself can act as an acid catalyst. Similarly, in one embodiment, component (B2) can be produced by a dehydration condensation reaction of a fatty acid (a1) and an alkanolamine (a3). Such a dehydration condensation reaction can be carried out, for example, by the following method: while heating the fatty acid (a1) and the alkanolamine (a3) ​​under reflux in the presence of an organic solvent that forms an azeotropic mixture with water, water generated by the condensation reaction is removed by azeotropy. In another embodiment, component (B1) can be produced by reacting a fatty acid (a1), an amine compound (a2) and a condensing agent in a solvent. Similarly, in one embodiment, component (B2) can be produced by reacting a fatty acid (a1), an alkanolamine (a3) ​​and a condensing agent in a solvent. As the condensing agent, carbodiimide-based condensing agents such as N,N'-dicyclohexylcarbodiimide (DCC), N,N'-diisopropylcarbodiimide (DIC), and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) can be used without particular limitation; imidazole-based condensing agents such as N,N'-carbonyldiimidazole (CDI) and 1,1'-carbonylbis(1,2,4-triazole) (CDT); triazine-based condensing agents such as 4-(4,6-dimethoxy-1,3,5-triazine-2-yl)-4-methylmorpholine hydrochloride hydrate (DMT-MM); 2- 2-halopyridinium salts such as chloro-1-methylpyridinium p-toluenesulfonate and 2-fluoro-1-methylpyridinium p-toluenesulfonate; 2,4,6-trichlorobenzoyl chloride (TCBC); 2-methyl-6-nitrobenzoic anhydride (MNBA); a combination of diethyl azodicarboxylate (DEAD) and triphenylphosphine; a combination of phosphines such as diphenylphosphine chloride and 2,2'-bipyridine disulfide; a combination of p-benzoquinones such as 2,6-dimethyl-1,4-benzoquinone (DMBQ) and tetrafluoro-1,4-benzoquinone; pentafluorobenzenesulfonic acid di-mesitylenylammonium salt, etc. are known condensing agents that can be used for esterification. The condensing agent can also be used together with a catalyst such as 4-dimethylaminopyridine (DMAP), N-hydroxysuccinimide (NHS), 1-hydroxybenzotriazole (HOBt), 1-hydroxy-7-azabenzotriazole (HOAt), etc. In another embodiment, component (B1) can be manufactured by reacting an acylating agent derived from a fatty acid (a1) with an amine compound (a2) in a solvent. Similarly, in one embodiment, component (B2) can be manufactured by reacting an acylating agent derived from a fatty acid (a1) with an alkanolamine (a3) ​​in a solvent. Examples of acylating agents derived from fatty acids (a1) include acyl halides (e.g., acyl chlorides, acyl bromides, etc.) of fatty acids (a1), active esters of fatty acids (a1) (e.g., esters of fatty acids (a1) with N-hydroxysuccinimide (NHS), esters of fatty acids (a1) with 1-hydroxybenzotriazole (HOBt), esters of fatty acids (a1) with 1-hydroxy-7-azabenzotriazole (HOAt), etc.), anhydrides of fatty acids (a1), etc. The acylating agent derived from fatty acids (a1) can also be used together with a catalyst such as 4-dimethylaminopyridine (DMAP). As the solvent, an organic solvent that does not interfere with the condensation reaction can be used without particular limitation (for example, aliphatic hydrocarbon solvents such as hexane and petroleum ether, aromatic hydrocarbon solvents such as benzene, toluene, and xylene, halogenated hydrocarbon solvents such as dichloromethane, 1,2-dichloroethane, chlorobenzene, and o-dichlorobenzene, pyridine, etc.). In addition, in the condensation reaction of the manufacturing component (B1) and / or (B2), as required, a suitable base (for example, amines such as triethylamine, pyridine, and 2,6-lutidine, organic lithium reagents such as butyl lithium, inorganic bases such as potassium carbonate, etc.) can be added to the reaction mixture for the purpose of promoting the reaction or for the purpose of capturing the acid generated as the reaction proceeds (for example, in the reaction using an acid halide, hydrogen halide is generated as the reaction proceeds). In another embodiment, component (B1) can be produced by a dehydration condensation reaction of component (B3) ((the third amide compound, which is an amide of one or more alkanolamines (a3) ​​represented by the general formula (1) and the monobasic fatty acid (a1) and does not have an ester bond) with an alkanolamine (a3) ​​and / or an amine compound (a2). Such a dehydration condensation reaction can be carried out, for example, by the following method: component (B3) and alkanolamine (a3) ​​or amine compound (a2) or a mixture thereof are heated to reflux in an organic solvent that forms an azeotropic mixture with water in the presence of an acid catalyst, and water generated by the condensation reaction is removed by azeotropy. In addition, the above-mentioned various dehydration condensation reactions can also be carried out in the absence of a solvent. For example, the dehydration condensation reaction can be carried out in the absence of a solvent while distilling off the water generated as the reaction proceeds.

[0094] In a preferred embodiment, a mixture containing component (B1) and component (B2) can be prepared by a dehydration condensation reaction of a fatty acid (a1) and an alkanolamine (a3). In one embodiment, such a dehydration condensation reaction can be carried out by the following method: while heating the fatty acid (a1) and the alkanolamine (a3) ​​under reflux in the presence of an organic solvent that forms an azeotropic mixture with water, water generated by the condensation reaction is removed by azeotropy. In another embodiment, when the boiling point of the alkanolamine (a3) ​​is higher than the boiling point of water, such a dehydration condensation reaction can be carried out by the following method: while heating and stirring the fatty acid (a1) and the alkanolamine (a3) ​​in the absence of a solvent, slowly increase the heating temperature to continue to distill off the water produced by the reaction, and continue heating and stirring until no water is distilled off even if the temperature is further increased. In addition, the above-mentioned dehydration condensation reaction can also be carried out in the absence of a solvent. For example, the dehydration condensation reaction can be carried out in the absence of a solvent while distilling off the water generated as the reaction proceeds. In the above dehydration condensation reaction, by-product component (B3) and / or component (B4) may be produced. In the reaction, the molar ratio of fatty acid (a1) to alkanolamine (a3) ​​((a3) / (a1)) is, for example, 0.01 to 100, preferably 0.02 to 50, or 0.5 to 5, or 1.5 to 2.0. In the above dehydration condensation reaction, a reaction in which two molecules of dialkanolamine (a3d) are disproportionated into one molecule of monoalkanolamine (a3m) and one molecule of trialkanolamine (a3t) (the following general formula (19)) may simultaneously proceed as a side reaction.

[0095]

Chemical formula 19

[0096]

Chemical formula 20

[0097]

Chemical formula 21

[0098]

Chemical formula 22

[0099]

Chemical formula 23

[0100]

Chemical formula 24

[0101]

Chemical formula 25

[0102] The by-product having a cyclic structure and acylated with the monobasic fatty acid (a1) (hereinafter sometimes referred to as "component (B5)" or "component (B5)") produced by the intramolecular dehydration cyclization reaction to produce the alkanolamine (a3) ​​or alkanolamine oligomer structure is usually produced in a small amount. The total content of the by-product in the lubricating oil composition as a content of the compound in a state not forming a salt may be, for example, 0 to 2.0% by mass or 0 to 5.0% by mass, based on the total content of all acylated products of the monobasic fatty acid (a1) in the compound containing the alkanolamine structure as a compound in a state not forming a salt. The hydroxyl group in the compound containing the alkanolamine structure may be etherified.

[0103] After the condensation reaction of fatty acid (a1) and dialkanolamine (a3) ​​is completed, the unreacted raw material can be removed by known methods such as water washing, silica gel short-path column chromatography, diatomaceous earth filtration, etc. During such operation, a solvent can be used appropriately. As a solvent, pentane, hexane, cyclohexane, heptane, benzene, toluene, xylene, ether, ethyl acetate, tetrahydrofuran, methanol, ethanol, isopropanol, dichloromethane, chloroform, carbon tetrachloride, etc. can be used. It is also possible to further refine the obtained product by column chromatography and other known refining means to adjust the content of each component of component (B1) to (B5). In addition, the so-called water washing here refers to cleaning based on water or an aqueous solution. As the aqueous solution for water washing, an acidic aqueous solution such as dilute hydrochloric acid, an alkaline aqueous solution such as a dilute sodium hydroxide aqueous solution, an aqueous solution of a salt such as a saturated salt solution, etc. can be used.

[0104] In the lubricating oil composition of the present invention, the above-mentioned components (B1) to (B5) function as oiliness agent-based friction modifiers. From the viewpoint of further improving the friction reduction performance while suppressing the reduction in storage stability of the lubricating oil composition, particularly the friction reduction performance on metal surfaces that are easily subjected to high loads such as gears, and from the viewpoint of further improving fatigue resistance, the total content of the above-mentioned components (B1), (B2), (B3) and (B4) in the lubricating oil composition, as calculated as compounds in a state not forming a salt, is preferably 0.001 mass % or more, 0.005 mass % or more, 0.010 mass % or more, 0.050 mass % or more, based on the total amount of the lubricating oil composition. % or more, 0.100 mass % or more, 0.30 mass % or more, from the viewpoint of further suppressing the reduction of electrical insulation, further improving the fatigue resistance and the storage stability, it is preferably 10.0 mass % or less, preferably 5.0 mass % or less or 4.0 mass % or less, and in one embodiment it can be 0.001 to 10.0 mass % or 0.005 to 10.0 mass %, 0.010 to 5.0 mass %, 0.050 to 5.0 mass %, 0.100 to 5.0 mass %, 0.30 to 4.0 mass %. From the same viewpoint, i.e., the viewpoint of further improving the friction reduction performance while suppressing the reduction in storage stability of the lubricating oil composition, in particular the friction reduction performance on metal surfaces such as gears that are easily subjected to high loads, and the viewpoint of further improving fatigue resistance, the total content of the components (B1), (B2), (B3), (B4) and (B5) in the lubricating oil composition is preferably 0.001% by mass or more, 0.005% by mass or more, or 0.010% by mass or more, based on the total amount of the lubricating oil composition, as a content of compounds in a state not forming a salt. , 0.050 mass % or more, 0.100 mass % or more, 0.30 mass % or more, and in addition, from the viewpoint of further suppressing the reduction of electrical insulation, further improving the fatigue resistance and storage stability, it is preferably 10.0 mass % or less, 5.0 mass % or less, 4.0 mass % or less, and in one embodiment it can be 0.001-10.0 mass % or 0.005-10.0 mass %, 0.010-5.0 mass %, 0.050-5.0 mass %, 0.100-5.0 mass %, 0.30-4.0 mass %. In addition, from the same viewpoint, i.e., from the viewpoint of further improving the friction reduction performance while suppressing the reduction in storage stability of the lubricating oil composition, in particular, from the viewpoint of further improving the friction reduction performance on metal surfaces that are easily subjected to high loads such as gears, and from the viewpoint of further improving fatigue resistance, the total content of all acylated products of the monovalent fatty acid (a1) of the compound containing an alkanolamine structure in the lubricating oil composition, calculated as a compound in a state not forming a salt, is preferably 0.001% by mass or more, 0.005% by mass or more, 0.010% by mass or more, 0.050% by mass or more, 0.100% by mass or more, based on the total amount of the composition. % by mass or more, 0.30% by mass or more, the hydroxyl group in the compound containing the alkanolamine structure may also be etherified, and from the viewpoint of further suppressing the reduction of electrical insulation, further improving the fatigue resistance and storage stability, it is preferably 10.0% by mass or less, preferably 5.0% by mass or less or 4.0% by mass or less, and in one embodiment it can be 0.001 to 10.0% by mass or 0.005 to 10.0% by mass, 0.010 to 5.0% by mass, 0.050 to 5.0% by mass, 0.100 to 5.0% by mass, 0.30 to 4.0% by mass. According to the lubricating oil additive composition of the present invention, by containing component (B1), compared with the case where component (B3) is used alone as a friction modifier, improved friction reducing performance, especially improved friction reducing performance in the mixed lubrication region and improved fatigue resistance can be obtained.

[0105] In the lubricating oil composition of the present invention, the content of the component (B2) may be zero, but from the viewpoint of improving the friction reducing performance and suppressing the decrease in electrical insulation, it is preferred that the following formula (eq1) is satisfied. M B2 / M B 1≧0.50…(eq1) (In formula (eq1), M B2 is the content of component (B2) based on the total amount of the composition (unit: mass %), M B 1 is the content of the component (B1) based on the total amount of the composition in terms of the compound not forming a salt (unit: mass %). Formula (eq1) represents the relative relationship between the content of component (B2) and the content of component (B1) in the lubricating oil composition. By making component (B2) exist in an amount satisfying formula (eq1) relative to the content of component (B1), the friction reduction performance is improved and the reduction in electrical insulation is suppressed, while fatigue resistance can be improved. Among components (B1) to (B5), component (B1) has a higher friction reduction effect, but on the other hand, it also has a significant tendency to reduce the electrical insulation of the lubricating oil composition. According to the research of the present inventors, it was found that: when component (B2) exists in an amount satisfying formula (eq1) relative to the content of component (B2) that does not satisfy formula (eq1), even if the absolute value of the content of component (B1) is at the same level, the adverse effect of component (B1) on the electrical insulation of the lubricating oil composition is greatly alleviated, and fatigue resistance is improved. In one embodiment, from the same point of view, the ratio M B2 / M B 1 is preferably 0.70 or more, or may be 0.85 or more. B2 / M B The upper limit of 1 is not particularly limited, but is preferably 10.0 or less, or may be 8.0 or less, or 7.0 or less, from the viewpoint of further improving the friction reducing effect.

[0106] The content of the component (B3) may be zero, but from the viewpoint of improving the friction reduction performance while further suppressing the reduction in electrical insulation and further improving the fatigue resistance, the content of the component (B2) preferably further satisfies the following (eq2). M B2 / (M B 1+M B3 )≧0.100…(eq2) (In formula (eq2), M B 1 and M B2 As defined above, M B3 is the content of component (B3) based on the total amount of the composition (unit: mass %). Formula (eq2) represents the relative relationship between the content of component (B2) and the total content of components (B1) and (B3). By making component (B2) exist in an amount satisfying formula (eq1) relative to the total content of components (B1) and (B3), while improving the friction reduction performance, the reduction in electrical insulation can be further suppressed and the fatigue resistance can be further improved. Among components (B1) to (B5), component (B3) provides a certain degree of friction reduction effect, but on the other hand, it tends to reduce the electrical insulation of the lubricating oil composition. According to the research of the present inventors, it was found that: when component (B2) exists in an amount satisfying formula (eq2) relative to the content of component (B2) that does not satisfy formula (eq2), even if the total content of components (B1) and (B3) is the same level, the adverse effects of components (B1) and (B3) on the electrical insulation of the lubricating oil composition are further alleviated, and the fatigue resistance is further improved. In one embodiment, from the same point of view, the ratio M B2 / (M B 1+M B3 ) is preferably 0.130 or more, or may be 0.150 or more. B2 / (M B 1+M B3 ) is not particularly limited, but from the viewpoint of further improving the friction reducing effect, it is preferably 5.0 or less, or may be 4.0 or less, or 3.0 or less.

[0107] In the present specification, the contents of components (B1) to (B5) in a sample can be measured using a high performance liquid chromatography (HPLC) apparatus. The measurement conditions of HPLC are as follows. [HPLC measurement conditions] Apparatus: UltiMate 3000 UHPLC manufactured by Thermo Fisher Scientific Column: ACQUITY (registered trademark) UPLC BEH C18 1.7 μm 50×2.1 mm (ODS) manufactured by Waters Corporation Detection device: Combination of charged particle detector (CAD) and mass spectrometer (MS) Charged particle detector (CAD): Corona (registered trademark) Veo (registered trademark) RS manufactured by Thermo Fisher Scientific, drying tube temperature: 35°C Mass spectrometer (MS): JMS-T100LP AccuTOF (registered trademark) LC-plus 4G manufactured by JEOL Ltd. (ionization method: ESI+) Mobile phase: A gradient elution method based on ultrapure water, methanol, and isopropanol was used. Ammonium formate was added to each solvent to a concentration of 10 mmol / L. Starting from a water / methanol mixing volume ratio of 20 / 80, the composition was continuously changed until methanol was 100%, and then the composition was further continuously changed until isopropanol was 100%. Column temperature: 40°C Sample solution: Methanol solution with a sample concentration of about 100 ppm by mass Sample injection volume: 1.0 μL Based on the detection results of the mass spectrometer (MS), each detection peak of the charged particle detector (CAD) can be attributed to a compound. As long as the analysis conditions are the same, the detection peak of CAD is independent of the characteristics of the compound and represents the area value corresponding to the amount of compound flowing into the detector. Therefore, by using the peak area value of CAD, the content of each component (converted to the mass % of the compound in the state where no salt is formed) can be quantitatively determined. In addition, when one detection peak of CAD contains multiple compounds, the content of each component (converted to the mass % of the compound in the state where no salt is formed) can be calculated by proportionally allocating the area value of the detection peak of CAD according to the ratio of the peak area values ​​of the multiple compounds based on MS. In the above-mentioned determination method, each detection peak of components (B1), (B2), (B4), and (B5) in the chromatogram of CAD is separated from the detection peaks of other components. In addition, the detection peak group of fatty acid acylation of alkanolamine oligomers in the chromatogram of CAD is separated from the detection peak group of fatty acid acylation of alkanolamine monomers. In addition, the detection peak of component (ii) in the chromatogram of CAD (i.e., a compound formed by acylation of the amino group and one or more hydroxyl groups of the alkanolamine monomer with fatty acids) is separated from the detection peak of fatty acid monoacylation of the alkanolamine monomer. The detection peak of component (B3) in the chromatogram of CAD (i.e., a fatty amide of the alkanolamine monomer and a component without an ester bond) is separated from each detection peak of components (B1), (B2), (B4), and (B5), but it may not be separated from the detection peak of fatty acid monoacylation of the alkanolamine monomer, i.e., monoester. In order to calculate the content of component (B3), it is necessary to proportionally distribute the detection peak area value of CAD based on the detection peak area of ​​MS. In the case of fatty acids and alkanolamines, their monoamides and monoesters have the same molecular weight, but the MS fragmentation patterns are different, so the two can be distinguished based on MS detection results. When the sample to be measured for the content of components (B1) to (B5) is not a complete solution (contains insoluble matter or is a suspension), the measurement can be performed after obtaining a solution by known pretreatment such as filtration. Before the measurement based on the above-mentioned high performance liquid chromatography (C18 column, detector: CAD and MS), a pretreatment can be performed as needed to remove all or part of the components other than components (B1) to (B5) by known purification methods such as silica gel column chromatography, preparative liquid chromatography separation (e.g., gel permeation chromatography (GPC), etc.).

[0108] ((C): Metal-based detergent) In a preferred embodiment, the lubricating oil composition may further contain one or more metal detergents (hereinafter sometimes referred to as "component (C)". Examples of component (C) include salicylate detergents, sulfonate detergents, phenate detergents, and the like. In addition, component (C) may contain only one metal detergent, or may contain two or more metal detergents. In addition, generally, in the field of lubricating oils, as metal detergents, organic acid metal salts that can form micelles in base oils (e.g., alkali metal or alkaline earth metal alkyl salicylates, alkali metal or alkaline earth metal alkylbenzene sulfonates, and alkali metal or alkaline earth metal alkylphenol salts, etc.), or mixtures of the organic acid metal salts and alkaline metal salts (e.g., hydroxides, carbonates, borates, etc. of alkali metals or alkaline earth metals constituting the organic acid metal salts, etc.) can be used. Such an organic acid usually has in one molecule at least one polar group with protonic acidity (e.g., carboxyl group, sulfonic acid group, phenolic hydroxyl group, etc.) that can form a salt with a metal base (typically a metal oxide and / or a metal hydroxide), and at least one lipophilic group such as a straight-chain or branched alkyl group (e.g., a straight-chain or branched alkyl group having more than 6 carbon atoms, etc.).

[0109] Examples of salicylate detergents include metal salicylates or basic salts thereof or overbased salts thereof. Preferred examples of metal salicylates include alkali metal or alkaline earth metal salicylates represented by the following general formula (26).

[0110]

Chemical formula 26

[0111] In the general formula (26), R 17 Each independently represents an alkyl or alkenyl group having 14 to 30 carbon atoms, M represents an alkali metal or an alkaline earth metal, a represents 1 or 2, and p represents 1 or 2 corresponding to the valence of M. When M is an alkali metal, p is 1, and when M is an alkaline earth metal, p is 2. M is preferably an alkaline earth metal. As the alkali metal, sodium or potassium is preferred, and as the alkaline earth metal, calcium or magnesium is preferred. As a, 1 is preferred. In addition, when a=2, R 17 It can also be a combination of different groups.

[0112] As a preferred embodiment of the salicylate-based detergent, there can be mentioned an alkaline earth metal salicylate or a basic salt thereof or a high-base salt thereof, wherein a=1 in the above general formula (26).

[0113] Preferred examples of sulfonate-based detergents include alkali metal or alkaline earth metal salts of alkyl aromatic sulfonic acids obtained by sulfonating alkyl aromatic compounds, or basic or overbased salts thereof, and more preferably alkaline earth metal salts or basic or overbased salts thereof. The weight average molecular weight of the alkyl aromatic compound is preferably 400 to 1500, and more preferably 700 to 1300. As the alkali metal, sodium or potassium is preferred, and as the alkaline earth metal, calcium or magnesium is preferred. As examples of alkyl aromatic sulfonic acids, so-called petroleum sulfonic acids and synthetic sulfonic acids can be cited. As examples of petroleum sulfonic acids, products of sulfonation of alkyl aromatic compounds of lubricating oil fractions of mineral oil, by-products of manufacturing white oil (white oil), i.e., so-called mahogany acid, etc. can be cited. In addition, as an example of synthetic sulfonic acids, by-products in alkylbenzene manufacturing plants that are recovered as raw materials for detergents can be cited, or products of sulfonation of alkylbenzenes with linear or branched alkyl groups obtained by alkylating benzene with polyolefins. As another example of synthetic sulfonic acids, products of sulfonation of alkylnaphthalenes such as dinonylnaphthalene can be cited. In addition, as sulfonating agents when these alkyl aromatic compounds are sulfonated, there is no particular restriction, for example, oleum and sulfuric anhydride can be used.

[0114] Preferred examples of phenate-based detergents include high-based salts of alkali metal or alkaline earth metal salts of compounds having a structure represented by the following general formula (27), and more preferably high-based salts of alkaline earth metal salts. The alkali metal is preferably sodium or potassium, and the alkaline earth metal is preferably calcium or magnesium.

[0115]

Chemical formula 27

[0116] In the general formula (27), R 18 represents a linear or branched, saturated or unsaturated alkyl or alkenyl group having 6 to 21 carbon atoms, q represents an integer of 0 to 9, A represents a thio (-S-) group or a methylene (-CH2-) group, and x represents an integer of 1 to 3. In addition, R 18 It can also be a combination of two or more different groups, and x can also be a combination of multiple different integers. When A is a methylene group, x is preferably 1. x The substitution position of the - group is typically the ortho or para position relative to the hydroxy group, and typically the ortho position.

[0117] From the viewpoint of improving solubility in the base oil, R in the general formula (27) 18 The number of carbon atoms in the moiety is preferably 9 or more, and is preferably 18 or less, more preferably 15 or less, from the viewpoint of ease of production. In one embodiment, it may be 9 to 18 or 9 to 15.

[0118] In the general formula (27), q is preferably 0-3.

[0119] The metal detergent can be overbased with a carbonate (e.g., an alkali metal carbonate such as sodium carbonate, potassium carbonate, or an alkaline earth metal carbonate such as calcium carbonate, magnesium carbonate, etc.) or a borate (e.g., an alkali metal borate such as sodium borate, potassium borate, or an alkaline earth metal borate such as calcium borate, magnesium borate, etc.).

[0120] In one embodiment, component (C) contains one or more high-based calcium or magnesium sulfonate detergents, one or more high-based calcium or magnesium salicylate detergents and / or one or more high-based calcium or magnesium phenate detergents, and preferably contains one or more high-based calcium sulfonate detergents and / or one or more high-based calcium salicylate detergents. The calcium sulfonate detergent, calcium salicylate detergent and calcium phenate detergent are preferably high-based with calcium carbonate, and the magnesium sulfonate detergent, magnesium salicylate detergent and magnesium phenate detergent are preferably high-based with magnesium carbonate.

[0121] The base value of the metal-based detergent can be appropriately determined according to the use of the lubricating oil composition. For example, when the lubricating oil composition is used for lubrication of a gear device such as a transmission (e.g., a manual transmission, an automatic transmission, a continuously variable transmission, etc.), the base value of the metal-based detergent is preferably 200 mgKOH / g or more from the viewpoint of improving wear resistance, anti-picking and transmission torque capacity of a wet clutch. In addition, from the same viewpoint and the viewpoint of further suppressing the reduction of electrical insulation, the base value is preferably 600 mgKOH / g or less, more preferably 550 mgKOH / g or less, and in one embodiment, it can be 200 to 600 mgKOH / g or 200 to 550 mgKOH / g. In addition, for example, when the lubricating oil composition is used for lubrication of an internal combustion engine, from the viewpoint of improving the cleaning performance and the base number maintenance, it is preferably 0 mgKOH / g or more, more preferably 20 mgKOH / g or more, and from the viewpoint of suppressing the ash content in the composition and the life of the exhaust gas after-treatment device, it is preferably 500 mgKOH / g or less, more preferably 450 mgKOH / g or less, and in one embodiment, it can be 0 to 500 mgKOH / g or 20 to 450 mgKOH / g. In addition, in this specification, the base number refers to the base number measured by the perchloric acid method according to JIS K2501.

[0122] When the lubricating oil composition contains component (C), its content can be appropriately determined according to the purpose of the lubricating oil composition. For example, when the lubricating oil composition is used for lubrication of a gear device such as a transmission (e.g., a manual transmission, an automatic transmission, a continuously variable transmission, etc.), from the viewpoint of improving wear resistance, pickling resistance, fatigue resistance, and the transmission torque capacity of a wet clutch, the content of component (C) in the lubricating oil composition is preferably 50 mass ppm or more or 100 mass ppm or more in terms of metal amount based on the total amount of the lubricating oil composition. In addition, from the viewpoint of improving fuel economy and fatigue resistance and further suppressing the reduction of electrical insulation, it is preferably 300 mass ppm or less or 250 mass ppm or less, and in one embodiment, it can be 50 to 300 mass ppm or 100 to 250 mass ppm. Furthermore, for example, when the lubricating oil composition is used for lubrication of an internal combustion engine, the content of the component (C) is preferably 500 mass ppm or more or 1000 mass ppm or more in terms of metal amount based on the total amount of the lubricating oil composition from the viewpoint of improving cleaning performance and base number maintenance, and is preferably 10000 mass ppm or less or 5000 mass ppm or less from the viewpoint of suppressing ash content in the composition and from the viewpoint of the life of the exhaust gas after-treatment device, and in one embodiment, may be 500 to 10000 mass ppm or 1000 to 5000 mass ppm.

[0123] ((D) Nitrogen-containing dispersant) In a preferred embodiment, the lubricating oil composition may further contain one or more nitrogen-containing dispersants (hereinafter sometimes referred to as "component (D)"). In the field of lubricating oils, nitrogen-containing dispersants generally include nitrogen-containing compounds having at least one long-chain (e.g., 40 or more carbon atoms) straight or branched aliphatic hydrocarbon group and at least one polyamine chain (typically, polyethyleneamine chain) in one molecule, or modified products (derivatives) thereof, wherein some nitrogen atoms of the polyamine chain may be acylated. Examples of modified products are as follows.

[0124] As the component (D), for example, one or more compounds selected from the following (D-1) to (D-3) can be used. (D-1) succinimide or a modified product (derivative) thereof having at least one alkyl group or alkenyl group in the molecule (hereinafter sometimes referred to as "component (D-1)"), (D-2) benzylamine having at least one alkyl or alkenyl group in the molecule (e.g., a Mannich base obtained by reaction of an alkyl or alkenylbenzene with formaldehyde or a polyamine) or a modified product (derivative) thereof (hereinafter sometimes referred to as "component (D-2)"), (D-3) N-alkyl or alkenylated polyamine having at least one alkyl or alkenyl group in the molecule, or a modified product (derivative) thereof (hereinafter sometimes referred to as "component (D-3)").

[0125] As the component (D), the component (D-1) can be particularly preferably used. In component (D-1), examples of succinimide having at least one alkyl or alkenyl group in the molecule include condensation reaction products of alkyl or alkenyl succinic acid or its anhydride and polyamine having an alkyl or alkenyl group having 40 to 400 carbon atoms. Such condensation reaction products (condensation products) can be represented by the following general formula (28a) or (28b), for example.

[0126]

Chemical formula 28

[0127] In the general formula (28a), R 19 represents an alkyl or alkenyl group having 40 to 400 carbon atoms, and b represents an integer of 1 to 10, preferably 2 to 6. In a typical embodiment, the compound represented by the general formula (28a) is obtained as a mixture of compounds having different b. From the viewpoint of solubility in the base oil, R 19 The number of carbon atoms is 40 or more, preferably 60 or more, and from the viewpoint of low temperature fluidity of the composition, it is 400 or less, preferably 350 or less, further preferably 250 or less, and in one embodiment it can be 40-400 or 60-350, 60-250.

[0128] In the general formula (28b), R 20 and R 21 Each independently represents an alkyl or alkenyl group having 40 to 400 carbon atoms, and may be a combination of different groups. In addition, c represents an integer of 0 to 15, preferably 1 to 13, and more preferably 1 to 11. In a typical embodiment, the compound represented by the general formula (28b) is obtained as a mixture of compounds having different c. From the viewpoint of solubility in the base oil, R 20 and R 21 The number of carbon atoms is 40 or more, preferably 60 or more, and from the viewpoint of low temperature fluidity of the composition, it is 400 or less, preferably 350 or less, further preferably 250 or less, and in one embodiment it can be 40-400 or 60-350, 60-250.

[0129] The alkyl or alkenyl group (R 19 ~R 21) may be straight-chain or branched. Preferred examples thereof include branched alkyl and alkenyl groups derived from oligomers of olefins such as propylene, 1-butene, and isobutylene, and co-oligomers of ethylene and propylene. Among them, branched alkyl or alkenyl groups derived from oligomers of isobutylene, which are conventionally referred to as polyisobutylene, and polybutenyl groups are most preferred. The alkyl or alkenyl group (R 19 ~R 21 ) has a preferred number average molecular weight of 800 to 3500, preferably 900 to 3500.

[0130] The succinimides having at least one alkyl or alkenyl group in the molecule include so-called mono-succinimides represented by the general formula (28a) in which only one end of the polyamine chain is imidized, and so-called bis-succinimides represented by the general formula (28b) in which both ends of the polyamine chain are imidized. The lubricating oil composition may contain either mono-succinimides or bis-succinimides, or may contain both of them as a mixture. The content of bis-succinimides or modified products thereof in the component (D-1) is preferably 50 to 100% by mass, more preferably 70 to 100% by mass, based on the total amount of the component (D-1) (100% by mass).

[0131] The weight average molecular weight of the component (D-1) is preferably 1,000 to 20,000, more preferably 2,000 to 20,000, further preferably 3,000 to 15,000, and in one embodiment, may be 4,000 to 15,000.

[0132] Examples of modified products (modified compounds, derivatives) in components (D-1) to (D-3) include (i) modified products of oxygen-containing organic compounds, (ii) boric acid modified products, (iii) phosphoric acid modified products, (iv) sulfur modified products, and (v) modified products of combinations of two or more of these. (i) Modified products based on oxygen-containing organic compounds are: modified compounds in which part or all of the remaining amino groups and / or imino groups are neutralized or amidated by allowing the above-mentioned succinimide, benzylamine or polyamine having at least one alkyl or alkenyl group in the molecule (hereinafter referred to as "the above-mentioned nitrogen-containing compound") to act with monocarboxylic acids having 1 to 30 carbon atoms such as fatty acids, polycarboxylic acids having 2 to 30 carbon atoms (for example, oxalic acid, phthalic acid, trimellitic acid, pyromellitic acid, etc.), their anhydrides or ester compounds, oxyalkylenes having 2 to 6 carbon atoms or hydroxy (poly)oxyalkylene carbonates. (ii) The boric acid-modified product is a modified compound in which a part or all of the remaining amino groups and / or imino groups are neutralized or amidated by reacting boric acid with the above-mentioned nitrogen-containing compound. (iii) The phosphoric acid-modified product is a modified compound in which a part or all of the remaining amino groups and / or imino groups are neutralized or amidated by reacting phosphoric acid with the above-mentioned nitrogen-containing compound. (iv) The sulfur-modified product is a modified compound obtained by reacting a sulfur compound with the above-mentioned nitrogen-containing compound. (v) Combination of Two or More Modifications The modified compound can be obtained by subjecting the above-mentioned nitrogen-containing compound to a combination of two or more modifications selected from the group consisting of modification with an oxygen-containing organic compound, boric acid modification, phosphoric acid modification, and sulfur modification. Among these modified products (derivatives) (i) to (v), boric acid-modified compounds of alkenyl succinimide, particularly bis-type boric acid-modified products of alkenyl succinimide, are preferably used.

[0133] When the lubricating oil composition contains component (D), its content can be appropriately determined according to the purpose of the lubricating oil composition. For example, when the lubricating oil composition is used for lubrication of a gear device such as a transmission (e.g., a manual transmission, an automatic transmission, a continuously variable transmission, etc.), from the viewpoint of improving oxidation stability, the content of component (D) in the lubricating oil composition is preferably 0.1% by mass or more based on the total amount of the lubricating oil composition, and from the viewpoint of maintaining energy saving and further suppressing the decrease in electrical insulation, it is preferably 10% by mass or less or 5% by mass or less. In addition, for example, from the viewpoint of improving coking resistance, when the lubricating oil composition is used for lubrication of an internal combustion engine, the content of component (D) is preferably 0.50% by mass or more or 1.00% by mass or more based on the total amount of the lubricating oil composition, and from the viewpoint of maintaining fuel economy, it is preferably 10.0% by mass or less or 5.0% by mass or less, and in one embodiment, it can be 0.50% by mass to 10.0% by mass or 1.00% by mass to 5.0% by mass.

[0134] As the (D) component, the (D-1) component can be preferably used, and as the modified substance in the (D) component, a boric acid modified substance can be preferably used. In one embodiment, the (D) component can be one or more unmodified (D-1) components (unmodified succinimide dispersants), can be one or more boric acid modified substances of the (D-1) components (boric acid modified succinimide dispersants), or can be a combination of one or more unmodified succinimide dispersants and one or more boric acid modified succinimide dispersants. The (D) component may or may not contain a boric acid modified substance, but from the viewpoint of sludge dispersibility, the ratio (B / N) of the content B of the boron content as the (D) component to the content N of the nitrogen content as the (D) component can be preferably 0 to 1.0 in one embodiment.

[0135] ((E) Phosphorus-containing antiwear agent) In a preferred embodiment, the lubricating oil composition may contain one or more phosphorus-containing antiwear agents (hereinafter sometimes referred to as "component (E)"). As component (E), any phosphorus-containing antiwear agent that can be used in lubricating oils can be used without particular limitation. Examples of the phosphorus-containing antiwear agent include compounds represented by the following general formula (29), compounds represented by the following general formula (30), and metal salts and ammonium salts thereof.

[0136]

Chemical formula 29

[0137]

Chemical formula 30

[0138] Examples of the hydrocarbon group having 1 to 30 carbon atoms in the general formulae (29) and (30) include alkyl, cycloalkyl, alkenyl, alkyl-substituted cycloalkyl, aryl, alkyl-substituted aryl, and aralkyl. The hydrocarbon group is preferably an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 24 carbon atoms, and in one embodiment, an alkyl group having 3 to 18 carbon atoms, and more preferably an alkyl group, aryl group, or alkylaryl group having 4 to 12 carbon atoms.

[0139] The hydrocarbon group having 1 to 30 carbon atoms in the general formulae (29) and (30) may be a hydrocarbon group containing a sulfur atom or may be a hydrocarbon group not containing a sulfur atom.

[0140] In one embodiment, preferred examples of the hydrocarbon group not containing a sulfur atom include linear alkyl groups having 4 to 18 carbon atoms. Examples of the linear alkyl group include butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, and octadecyl.

[0141] Examples of the hydrocarbon group containing a sulfur atom include hydrocarbon groups functionalized with a sulfur bond. Preferred examples of the hydrocarbon group functionalized with a sulfur bond include groups having 4 to 20 carbon atoms represented by the following general formula (31).

[0142]

Chemical formula 31

[0143] Preferred examples of the group represented by the general formula (31) include 3-thiopentyl, 3-thiohexyl, 3-thioheptyl, 3-thiooctyl, 3-thiononyl, 3-thiodecyl, 3-thioundecyl and 4-thiohexyl.

[0144] Examples of metals that form metal salts with the phosphorus compound represented by the general formula (29) or (30) include alkali metals such as lithium, sodium, potassium, and cesium, alkaline earth metals such as calcium, magnesium, and barium, and transition metals such as zinc, copper, iron, lead, nickel, silver, and manganese. Among them, alkaline earth metals such as calcium and magnesium or zinc, or a combination thereof, are preferred.

[0145] Examples of nitrogen-containing compounds that form ammonium salts with the phosphorus compound represented by the general formula (29) or (30) include ammonia, monoamines, diamines, polyamines, and alkanolamines. More specifically, examples include nitrogen-containing compounds represented by the following general formula (32); alkylenediamines such as methylenediamine, ethylenediamine, propylenediamine, and butylenediamine; polyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine; and combinations thereof.

[0146]

Chemical formula 32

[0147] Preferred examples of the compound represented by the general formula (29) include phosphite compounds, wherein in the general formula (29), X 1 ~X 3 is an oxygen atom, R 22 ~R 24 are independently an alkyl group, an aryl group (such as a phenyl group) or an alkylaryl group (such as an alkylphenyl group) having 3 to 18 carbon atoms (preferably 4 to 12 carbon atoms) and may contain a sulfur atom; a hydrogen phosphite compound, wherein in the above general formula (29), X 1 ~X 3 is an oxygen atom, R 22 and R 23 Each of them is independently an alkyl group having 3 to 18 (preferably 4 to 12) carbon atoms, an aryl group (such as a phenyl group) or an alkylaryl group (such as an alkylphenyl group) which may contain a sulfur atom. 24 is hydrogen; a thiophosphite compound, wherein in the above general formula (29), X 1 ~X 3 Two of them are oxygen atoms and the other one is a sulfur atom. 22 and R 23 Each of them is independently an alkyl group having 3 to 18 (preferably 4 to 12) carbon atoms, an aryl group (such as a phenyl group) or an alkylaryl group (such as an alkylphenyl group) which may contain a sulfur atom. 24 is hydrogen; and dithiophosphite compounds, wherein in the above general formula (29), X 1 ~X 3 One of them is oxygen atom and the other two are sulfur atoms. 22 and R 23 Each of them is independently an alkyl group having 3 to 18 (preferably 4 to 12) carbon atoms, an aryl group (such as a phenyl group) or an alkylaryl group (such as an alkylphenyl group) which may contain a sulfur atom. 24 For hydrogen; etc. Preferred examples of the compound represented by the general formula (30) include dithiophosphate compounds, wherein in the general formula (30), X 4 ~X 7 Two of them are sulfur atoms and the other two are oxygen atoms. 25 ~R 27Each independently represents an alkyl group, an aryl group or an alkylaryl group having 3 to 18 (preferably 4 to 12) carbon atoms which may contain a sulfur atom. These compounds may be used alone or in combination of two or more.

[0148] An example of the component (E) is zinc dialkyl dithiophosphate (ZnDTP). An example of zinc dialkyl dithiophosphate is a compound represented by the following general formula (33).

[0149]

Chemical formula 33

[0150] When the lubricating oil composition contains component (E), its content can be appropriately determined according to the purpose of the lubricating oil composition. For example, when the lubricating oil composition is used for lubrication of a gear device such as a transmission (e.g., a manual transmission, an automatic transmission, a continuously variable transmission, etc.), from the viewpoint of improving wear resistance, anti-picking, bearing fatigue life, and prevention of speed change shock, the content of component (E) in the lubricating oil composition is preferably 50 mass ppm or more or 100 mass ppm or more in terms of phosphorus content based on the total amount of the lubricating oil composition. In addition, from the same viewpoint and from the viewpoint of further suppressing the reduction of electrical insulation, it is preferably 800 mass ppm or less or 700 mass ppm or less, and in one embodiment, it can be 50 to 800 mass ppm or 100 to 700 mass ppm. Furthermore, for example, when the lubricating oil composition is used for lubrication of an internal combustion engine, the content of the component (E) is preferably 400 mass ppm or more or 500 mass ppm or more in terms of phosphorus content based on the total amount of the lubricating oil composition from the viewpoint of improving wear resistance, and is preferably 5000 mass ppm or less or 3000 mass ppm or less from the viewpoint of reducing catalyst poisoning of an exhaust gas after-treatment device, and in one embodiment may be 400 to 5000 mass ppm or 500 to 3000 mass ppm.

[0151] ((F) Sulfur-containing extreme pressure agent) In a preferred embodiment, the lubricating oil composition may further contain one or more sulfur-containing extreme pressure agents other than the component (E) (hereinafter referred to as "component (F)"). Examples of component (F) include known sulfur-containing extreme pressure agents such as thiadiazole compounds, dialkyl (poly)sulfides, sulfurized oils and fats, sulfurized fatty acids, sulfurized esters, sulfurized olefins, alkylthiocarbamoyl compounds, thiocarbamate compounds, thioterpene compounds, dialkylthiodipropionate compounds, sulfurized mineral oils, zinc dithiocarbamate compounds, and molybdenum dithiocarbamate compounds.

[0152] Preferred examples of the thiadiazole compound include 1,3,4-thiadiazole compounds represented by the following general formula (34), 1,2,4-thiadiazole compounds represented by the following general formula (35), and 1,2,3-thiadiazole compounds represented by the following general formula (36).

[0153]

Chemical formula 34

[0154]

Chemical formula 35

[0155]

Chemical formula 36

[0156] The dialkyl (poly)sulfide is a compound represented by the following general formula (37). 31 and R 32 When it is an alkyl group, it is sometimes called an alkyl sulfide.

[0157]

Chemical formula 37

[0158] When the lubricating oil composition contains the component (F), its content can be appropriately determined according to the purpose of the lubricating oil composition. For example, when the lubricating oil composition is used for lubrication of a gear device such as a transmission (e.g., a manual transmission, an automatic transmission, a continuously variable transmission, etc.), from the viewpoint of improving extreme pressure resistance and fatigue resistance, the content of the component (F) in the lubricating oil composition is preferably 200 mass ppm or more or 300 mass ppm or more in terms of sulfur content based on the total amount of the lubricating oil composition. Furthermore, from the viewpoint of improving wear resistance, fatigue resistance and oxidation stability and further suppressing the reduction of electrical insulation, it is preferably 3000 mass ppm or less or 2500 mass ppm or less, and in one embodiment, it can be 200 to 3000 mass ppm or 300 to 2500 mass ppm. Furthermore, for example, when the lubricating oil composition is used for lubrication of an internal combustion engine, the content of the component (F) is preferably 10 mass ppm or more or 30 mass ppm or more in terms of sulfur content based on the total amount of the lubricating oil composition from the viewpoint of improving extreme pressure resistance and fatigue resistance, and is preferably 200 mass ppm or less or 100 mass ppm or less from the viewpoint of reducing catalyst poisoning of an exhaust gas after-treatment device, and in one embodiment may be 10 to 200 mass ppm or 30 to 100 mass ppm.

[0159] ((G) Antioxidant) In a preferred embodiment, the lubricating oil composition may further contain one or more amine antioxidants and / or one or more phenolic antioxidants as antioxidants (hereinafter sometimes referred to as "component (G)").

[0160] Examples of amine antioxidants include aromatic amine antioxidants and hindered amine antioxidants. Examples of aromatic amine antioxidants include aromatic primary amine compounds such as alkylated α-naphthylamine, and aromatic secondary amine compounds such as alkylated diphenylamine, phenyl-α-naphthylamine, alkylated phenyl-α-naphthylamine, and phenyl-β-naphthylamine. As aromatic amine antioxidants, alkylated diphenylamine or alkylated phenyl-α-naphthylamine, or a combination thereof, can be preferably used.

[0161] Examples of hindered amine antioxidants include compounds having a 2,2,6,6-tetraalkylpiperidine skeleton (2,2,6,6-tetraalkylpiperidine derivatives). As 2,2,6,6-tetraalkylpiperidine derivatives, 2,2,6,6-tetraalkylpiperidine derivatives having a substituent at the 4-position are preferred. In addition, two 2,2,6,6-tetraalkylpiperidine skeletons may be bonded via respective substituents at the 4-position. In addition, the N-position of the 2,2,6,6-tetraalkylpiperidine skeleton may be unsubstituted, or the N-position may be substituted with an alkyl group having 1 to 4 carbon atoms. The 2,2,6,6-tetraalkylpiperidine skeleton is preferably a 2,2,6,6-tetramethylpiperidine skeleton.

[0162] Examples of the substituent at the 4-position of the 2,2,6,6-tetraalkylpiperidine skeleton include an acyloxy group (R 41 COO-), alkoxy (R 41 O-), alkylamino (R 41 NH-), acylamino (R 41 CONH-) etc. 41 The hydrocarbon group preferably has 1 to 30 carbon atoms, more preferably 1 to 24 carbon atoms, and still more preferably 1 to 20 carbon atoms. Examples of the hydrocarbon group include alkyl, alkenyl, cycloalkyl, alkylcycloalkyl, aryl, alkylaryl, and aralkyl groups.

[0163] Examples of the substituent when two 2,2,6,6-tetraalkylpiperidine skeletons are bonded via the substituent at the 4-position include alkylenebis(carbonyloxy) groups (-OOC-R 42 -COO-), alkylene diamino (-HN-R 42 -NH-), alkylenebis(carbonylamino) (-HNCO-R 42 -CONH-) etc. 42 A hydrocarbylene group having 1 to 30 carbon atoms is preferred, and an alkylene group is more preferred.

[0164] As the substituent at the 4-position of the 2,2,6,6-tetraalkylpiperidine skeleton, an acyloxy group is preferred. As an example of a compound having an acyloxy group at the 4-position of the 2,2,6,6-tetraalkylpiperidine skeleton, an ester of 2,2,6,6-tetramethyl-4-piperidinol and a carboxylic acid can be cited. As an example of the carboxylic acid, a linear or branched aliphatic carboxylic acid having 8 to 20 carbon atoms can be cited.

[0165] Examples of phenolic antioxidants include 4,4'-methylenebis(2,6-di-tert-butylphenol); 4,4'-bis(2,6-di-tert-butylphenol); 4,4'-bis(2-methyl-6-tert-butylphenol); 2,2'-methylenebis(4-ethyl-6-tert-butylphenol); 2,2'-methylenebis(4-methyl-6-tert-butylphenol); 4,4'-butylenebis(3-methyl-6-tert-butylphenol); 4,4'-isopropylidenebis(2,6-di-tert-butylphenol); 2,2'-methylenebis(4-methyl-6-nonylphenol); 2,2'-isobutylenebis(4,6-dimethylphenol); 2,2'-methylenebis(4-methyl-6-cyclohexylphenol); 2,6-di-tert-butylphenol; Butyl-4-methylphenol; 2,6-di-tert-butyl-4-ethylphenol; 2,4-dimethyl-6-tert-butylphenol; 2,6-di-tert-butyl-4-(N,N'-dimethylaminomethyl)phenol; 4,4'-thiobis(2-methyl-6-tert-butylphenol); 4,4'-thiobis(3-methyl-6-tert-butylphenol); 2,2'-thiobis(4-methyl-6-tert-butylphenol); bis(3-methyl-4-hydroxy-5-tert-butylbenzyl) sulfide; bis(3,5-di-tert-butyl-4-hydroxybenzyl) sulfide; 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate; 3-methyl-5-tert-butyl-4-hydroxyphenol fatty acid esters and other hindered phenol compounds and bisphenol compounds.

[0166] When the lubricating oil composition contains the component (G), the content thereof can be appropriately determined according to the use of the lubricating oil composition. For example, when the lubricating oil composition is used for lubrication of a gear device such as a transmission (e.g., a manual transmission, an automatic transmission, a continuously variable transmission, etc.), the content of the component (G) in the lubricating oil composition is preferably 0.100% by mass or more or 0.20% by mass or more based on the total amount of the lubricating oil composition from the viewpoint of improving thermal oxidation stability, and is preferably 2.0% by mass or less or 1.00% by mass or less from the same viewpoint and from the viewpoint of further suppressing a decrease in electrical insulation, and in one embodiment, may be 0.100 to 2.0% by mass or 0.20 to 1.00% by mass. Furthermore, for example, when the lubricating oil composition is used for lubrication of an internal combustion engine, from the viewpoint of improving thermal oxidation stability, the content of the component (G) in the lubricating oil composition is preferably 0.100 mass % or more or 0.50 mass % or more based on the total amount of the lubricating oil composition. Furthermore, from the same viewpoint, it is preferably 5.0 mass % or less or 3.0 mass % or less, and in one embodiment, it may be 0.100 to 5.0 mass % or 0.50 to 3.0 mass %.

[0167] ((H)Viscosity index improver) In a preferred embodiment, the lubricating oil composition may further contain one or more polymers having a viscosity index improving effect (hereinafter sometimes referred to as "viscosity index improver" or "(H) component".). Examples of the (H) component include non-dispersed or dispersed poly(meth)acrylates, (meth)acrylate-olefin copolymers, non-dispersed or dispersed ethylene-α-olefin copolymers or their hydrogenates, polyisobutylene or their hydrogenates, styrene-diene hydrogenated copolymers, styrene-maleic anhydride copolymers, and polyalkylstyrenes. In addition, in this specification, "(meth)acrylate" means "acrylate and / or methacrylate". As the (H) component, one polymer may be used alone, or two or more polymers may be used in combination.

[0168] In one embodiment, as the (H) component, a dispersed poly (meth) acrylate or a non-dispersed poly (meth) acrylate, or a combination thereof, may be preferably used. In one embodiment, a dispersed poly (meth) acrylate may be preferably used. In addition, in this specification, the dispersed poly (meth) acrylate compound has a functional group containing a nitrogen atom, while the non-dispersed poly (meth) acrylate compound does not have a functional group containing a nitrogen atom.

[0169] In one embodiment, as a poly(meth)acrylate-based viscosity index improver, a poly(meth)acrylate (hereinafter sometimes referred to as "poly(meth)acrylate (H1)" or simply "(H1) component") in which the structural unit represented by the following general formula (38) accounts for 10 to 90 mol% of all monomer units in the polymer can be preferably used.

[0170]

Chemical formula 38

[0171] The weight average molecular weight of the component (H) can be appropriately determined according to the application of the lubricating oil composition. For example, when the lubricating oil composition is used for lubrication of a gear device such as a transmission (e.g., a manual transmission, an automatic transmission, a continuously variable transmission, etc.), the weight average molecular weight of the component (H) is preferably 10,000 or more, more preferably 20,000 or more, and further preferably 30,000 or more from the viewpoint of improving the viscosity index improvement effect and improving the low-temperature viscosity characteristics. In addition, from the viewpoint of improving the solubility in the base oil, storage stability, and shear stability, it is preferably 200,000 or less, more preferably 150,000 or less, and further preferably 100,000 or less. In one embodiment, it can be 10,000 to 200,000, 20,000 to 150,000, or 30,000 to 100,000. Furthermore, for example, when the lubricating oil composition is used for lubrication of an internal combustion engine, the weight average molecular weight of the component (H) is preferably 100,000 or more, more preferably 200,000 or more, from the viewpoint of improving the viscosity index improvement effect, improving the low-temperature viscosity characteristics and the fuel economy, and is preferably 1,000,000 or less, more preferably 700,000 or less, from the viewpoint of improving the solubility in oil, storage stability and shear stability, and in one embodiment, may be 100,000 to 1,000,000 or 200,000 to 700,000.

[0172] When the lubricating oil composition contains the component (H), its content can be appropriately determined according to the amount that can obtain the desired kinematic viscosity and viscosity-temperature characteristics as the lubricating oil composition as a whole. For example, the viscosity index is an index for evaluating the viscosity-temperature characteristics. For example, when the lubricating oil composition is used for lubrication of a gear device such as a transmission (e.g., a manual transmission, an automatic transmission, a continuously variable transmission, etc.), from the viewpoint of improving the viscosity-temperature characteristics and improving energy saving, the content of the component (H) in the lubricating oil composition is, for example, 0.100% by mass or more or 0.50% by mass or more in terms of resin content based on the total amount of the lubricating oil composition. In addition, from the viewpoint of improving shear stability, it is, for example, 22% by mass or less or 12.0% by mass or less. In one embodiment, it can be 0.100 to 22% by mass or 0.50 to 12.0% by mass. In addition, for example, when the lubricating oil composition is used for lubrication of an internal combustion engine, the content of the component (H) in the lubricating oil composition is, for example, 0.100 mass % or more or 0.50 mass % or more in terms of resin content based on the total amount of the lubricating oil composition from the viewpoint of improving fuel economy, and is, for example, 20 mass % or less or 15.0 mass % or less from the viewpoint of improving shear stability, and in one embodiment, may be 0.100 to 20 mass % or 0.50 to 15.0 mass %. In addition, in this specification, the resin content refers to a polymer component having a molecular weight of 1,000 or more.

[0173] (Other additives) The lubricating oil composition of the present invention may further contain one or more additives selected from the group consisting of (I) a friction modifier other than the above-mentioned components (B1) to (B5) and the component (F), (J) a pour point depressant other than the above-mentioned component (H), (K) a corrosion inhibitor other than the above-mentioned component (F), (L) a metal deactivator other than the above-mentioned component (F), (M) a rust inhibitor other than the above-mentioned components (B1) to (B5), (N) an anti-emulsifier, (O) a defoaming agent, and (P) a colorant.

[0174] As the friction modifier (I) other than the above-mentioned components (B1) to (B5) and component (F) (hereinafter sometimes referred to as "component (I)"), an oil-soluble organic molybdenum compound or an oiliness-based friction modifier used as a friction modifier in a lubricating oil can be used. Compounds other than the above-mentioned components (B1) to (B5) and component (F) can be used. Examples of such compounds include oil-soluble organic molybdenum compounds other than the molybdenum dithiocarbamate described above as an example of component (F), and oiliness-based friction modifiers other than the above-mentioned components (B1) to (B5). The lubricating oil composition may or may not contain the component (I). When the lubricating oil composition contains the component (I), the content thereof may be, for example, 0.100 to 1.00% by mass based on the total amount of the lubricating oil composition.

[0175] As (J) a pour point depressant other than the above-mentioned (H) component (hereinafter sometimes referred to as "component (I)"), a known pour point depressant such as ethylene-vinyl acetate copolymer can be used, depending on the properties of the lubricating base oil used. The lubricating oil composition may not contain component (J), but when the lubricating oil composition contains component (J), the content thereof may be, for example, 0.010 to 1.00% by mass based on the total amount of the lubricating oil composition.

[0176] As the anticorrosive agent (K) other than the above-mentioned component (F) (hereinafter sometimes referred to as "component (K)"), for example, a benzotriazole compound, a tolyltriazole compound, an imidazole compound or the like known anticorrosive agents can be used. The lubricating oil composition may not contain component (K), but when the lubricating oil composition contains component (K), the content thereof may be, for example, 0.005 to 5.0% by mass based on the total amount of the lubricating oil composition.

[0177] As the metal deactivator (L) other than the above-mentioned component (F) (hereinafter sometimes referred to as "component (L)"), for example, known metal deactivators such as imidazoline, pyrimidine derivatives, mercaptobenzothiazole, benzotriazole and its derivatives, 2-(alkyldithio)benzimidazole and β-(o-carboxybenzylthio)propionitrile can be used. The lubricating oil composition may not contain the component (L), but when the lubricating oil composition contains the component (L), the content thereof may be, for example, 0.005 to 1.00% by mass based on the total amount of the lubricating oil composition.

[0178] As the rust inhibitor (M) other than the above-mentioned components (B1) to (B5) (hereinafter sometimes referred to as "component (M)"), for example, known rust inhibitors such as petroleum sulfonates, alkylbenzene sulfonates, dinonylnaphthalene sulfonates, alkenyl succinates, and polyol esters (excluding the above-mentioned components (B1) to (B5)) can be used. The lubricating oil composition may not contain component (M), but when the lubricating oil composition contains component (M), its content may be, for example, 0.005 to 5.0% by mass based on the total amount of the lubricating oil composition.

[0179] As the (N) demulsifier, for example, a known demulsifier such as a polyalkylene glycol-based nonionic surfactant can be used. The lubricating oil composition may not contain the (N) component, but when the lubricating oil composition contains the demulsifier, the content thereof may be, for example, 0.005 to 5.0% by mass based on the total amount of the lubricating oil composition.

[0180] As the (O) defoaming agent, for example, known defoaming agents such as silicone, fluorosilicone, and fluoroalkyl ether can be used. The lubricating oil composition may not contain a defoaming agent, but when the lubricating oil composition contains a defoaming agent, the content thereof may be, for example, 0.0005 to 1.00% by mass based on the total amount of the lubricating oil composition.

[0181] As the colorant (P), for example, a known colorant such as an azo compound can be used.

[0182] (Properties of Lubricating Oil Composition) The kinematic viscosity of the lubricating oil composition at 100°C can be appropriately determined according to the application of the lubricating oil composition. For example, when the lubricating oil composition is used for lubrication of a gear device such as a transmission (e.g., a manual transmission, an automatic transmission, a continuously variable transmission, etc.), the kinematic viscosity of the lubricating oil composition at 100°C is preferably 1.0 mm / s from the viewpoint of improving wear resistance. 2 / s or more, more preferably 2.5m 2 / s or more, and preferably 10.0 mm from the viewpoint of improving energy saving 2 / s or less, more preferably 7.0 mm 2 / s or less or 6.9mm 2 / s or less, and in one embodiment, may be 1.0 to 10.0 mm 2 / s or 1.0~7.0mm 2 / s, 1.0~6.9mm 2 / s, 2.5~10.0mm 2 / s, 2.5~7.0mm 2 In addition, for example, when the lubricating oil composition is used for lubrication of an internal combustion engine, the kinematic viscosity of the lubricating oil composition at 100° C. is preferably 2.0 mm / s from the viewpoint of improving wear resistance. 2 / s or more, more preferably 4.0 mm 2 / s or more, and preferably 12.5 mm from the viewpoint of improving energy saving 2 / s or less, more preferably 9.3 mm 2 / s or less, and in one embodiment, may be 2.0 to 12.5 mm 2 / s or 4.0~12.5mm 2 / s, 2.0~9.3mm 2 / s, 4.0~9.3mm 2 / s. From the viewpoint of reducing stirring resistance and improving energy saving efficiency, it is preferred that the kinematic viscosity of the lubricating oil composition is lower. On the other hand, when the kinematic viscosity of the composition is low, the oil film thickness is easily reduced, so compared with a lubricating oil with a higher viscosity, it shifts from the fluid lubrication area to the mixed lubrication area at a lower load, and the friction coefficient begins to increase. This problem is particularly serious in the lubrication of gears where the load applied to the lubricating surface increases in proportion to the transmitted driving force. By containing the (B1) component, the lubricating oil composition of the present invention can improve the friction reduction performance, especially the friction reduction performance in the mixed lubrication area, even if the kinematic viscosity of the composition is low.

[0183] The kinematic viscosity of the lubricating oil composition at 40°C can be appropriately determined according to the application of the lubricating oil composition. For example, when the lubricating oil composition is used for lubrication of a gear device such as a transmission (e.g., a manual transmission, an automatic transmission, a continuously variable transmission, etc.), the kinematic viscosity of the lubricating oil composition at 40°C is preferably 2.0 mm / s from the viewpoint of improving wear resistance. 2 / s or more, more preferably 5.0 mm 2 / s or more, and from the viewpoint of improving energy saving, 50 mm is preferred. 2 / s or less, more preferably 45mm 2 / s or less, and in one embodiment, may be 2.0 to 50 mm 2 / s or 2.0~45mm 2 / s, 5.0~50mm 2 / s, 5.0~45mm 2 / s. For example, when the lubricating oil composition is used for lubrication of an internal combustion engine, the kinematic viscosity of the lubricating oil composition at 40° C. is preferably 4.0 mm / s from the viewpoint of improving wear resistance. 2 / s or more, more preferably 6.0 mm 2 / s or more, and from the viewpoint of improving energy saving, 50 mm is preferred 2 / s or less, more preferably 35mm 2 / s or less, and in one embodiment, may be 4.0 to 50 mm 2 / s or 6.0~50mm 2 / s, 4.0~35mm 2 / s, 6.0~35mm 2 / s.

[0184] From the viewpoint of further improving energy saving performance and wear resistance, the viscosity index of the lubricating oil composition is preferably 100 or more, more preferably 110 or more, and in one embodiment, may be 115 or more or 120 or more.

[0185] In one embodiment, the lubricating oil composition (in a new oil state) preferably has a volume resistivity of 2.1×10 9 Ω·cm or more. In this specification, the volume resistivity of the lubricating oil composition refers to the volume resistivity measured at an oil temperature of 80° C. according to the volume resistivity test specified in JIS C2101.

[0186] (use) The lubricating oil composition of the present invention can be widely used in the lubrication field. The lubricating oil composition of the present invention can suppress the reduction of electrical insulation and improve the friction reduction performance, especially the friction reduction effect in the mixed lubrication area (such as the lubrication conditions of gears, etc.), and improve fatigue resistance by containing the components (B1) and (B2) and satisfying the formula (eq1). The lubricating oil composition of the present invention can exert an improved friction reduction effect in the lubrication of metal surfaces that are easily subjected to high loads such as gears, and also exerts improved fatigue resistance. In addition to being preferably used for the lubrication of various mechanical devices having metal surfaces that are easily subjected to high loads such as gear mechanisms, pistons, and connecting rod bearings, it can be preferably used for the lubrication of transmissions (such as manual transmissions, automatic transmissions, continuously variable transmissions, speed reducers for electric vehicles, speed increasers for wind turbines, etc.) and internal combustion engines, and can also be preferably used for lubrication of various industrial uses (such as hydraulic working oils, turbine oils, compressor oils). Furthermore, the lubricating oil composition of the present invention has improved friction reduction performance and fatigue resistance while suppressing the reduction of electrical insulation, so it can be preferably used as a motor oil, a transmission oil, a common lubricating oil for a motor and a transmission (gear mechanism), or a lubricating oil for an electric drive module equipped with a motor and a transmission (gear mechanism). In one embodiment, the lubricating oil composition of the present invention can be preferably used for the lubrication of a motor in a car equipped with a motor, or the lubrication of the motor and the transmission in a car equipped with a motor and a transmission (gear mechanism). In one embodiment, the lubricating oil composition of the present invention can be preferably used as a cooling oil for cooling components of an electric system such as a battery and a power electronic machine. In one embodiment, the lubricating oil composition of the present invention can be preferably used as a common lubricating / cooling oil for a transmission (gear device) or a motor or a combination thereof, a battery or one or more power electronic machines or a combination thereof. In one embodiment, the lubricating oil composition of the present invention can be preferably used as a common lubricating / cooling oil for an electric drive module equipped with a motor and a transmission (gear mechanism), a battery or one or more power electronic machines or a combination thereof. [Example]

[0187] The present invention will be described in further detail below based on Examples and Comparative Examples. In addition, the following Examples are intended to illustrate the present invention and are not intended to limit the present invention.

[0188] <Production Examples 1 to 7> According to the following procedure, friction modifier compositions having the compositions described in Tables 1 to 5 were prepared. In Tables 1 to 5, the unit "mass %" of the content represents mass % based on the total amount of the friction modifier composition. (Measurement method) For the measurement of IR (infrared spectroscopy) spectrum, FT / IR-4100 manufactured by JASCO Corporation was used. A solid sample at room temperature was heated and melted, and a small amount was applied on a KBr plate for measurement. A liquid sample at room temperature was directly applied on a KBr plate for measurement.

[0189] The content of each component in the additive composition can be measured by high performance liquid chromatography (HPLC). The measurement conditions of HPLC analysis are as follows. [HPLC measurement conditions] Apparatus: UltiMate 3000 UHPLC manufactured by Thermo Fisher Scientific Column: ACQUITY (registered trademark) UPLC BEH C18 1.7 μm 50×2.1 mm (ODS) manufactured by Waters Corporation Detection device: Combination of charged particle detector (CAD) and mass spectrometer (MS) Charged particle detector (CAD): Corona (registered trademark) Veo (registered trademark) RS manufactured by Thermo Fisher Scientific, drying tube temperature: 35°C Mass spectrometer (MS): JMS-T100LP AccuTOF (registered trademark) LC-plus 4G manufactured by JEOL Ltd. (ionization method: ESI+) Mobile phase: A gradient elution method based on ultrapure water, methanol, and isopropanol was used. Ammonium formate was added to each solvent to a concentration of 10 mmol / L. Starting from a water / methanol mixing volume ratio of 20 / 80, the composition was continuously changed until methanol was 100%, and then the composition was further continuously changed until isopropanol was 100%. Column temperature: 40°C Sample solution: Methanol solution with a sample concentration of about 100 ppm by mass Sample injection volume: 1.0 μL Based on the detection results of the mass spectrometer (MS), each detection peak of the charged particle detector (CAD) is attributed to a compound. By using the peak area value of CAD, the content of each component (converted to the mass % of the compound in a state where no salt is formed) is quantified. When one detection peak of CAD contains multiple compounds, the content of each component (converted to the mass % of the compound in a state where no salt is formed) can be calculated by proportionally allocating the area value of the detection peak of CAD according to the ratio of the peak area values ​​of the multiple compounds based on MS.

[0190] (Production Example 1) Add 5.0 mol of oleic acid and 7.5 mol of DEA to a 5L three-necked flask equipped with a distillation tube together with a magnetic stirrer, replace the interior of the flask with nitrogen, and stir the contents of the flask with a magnetic stirrer to make a uniform mixture. While stirring the mixture in the flask with a magnetic stirrer, heat the flask in an oil bath. Slowly increase the heating temperature of the oil bath to allow water to continue to distill. Track the reaction with IR spectroscopy, and confirm the end of the reaction by IR spectroscopy after 24 hours from the start of the reaction. The heating temperature of the oil bath at the end of the reaction is 180°C. Place the contents of the cooled flask and dry under reduced pressure to obtain a crude product. The obtained crude product was purified by preparative HPLC to prepare a friction modifier composition. The compositions thereof analyzed by high performance liquid chromatography (LC / MS / CAD) are shown in Table 1.

[0191]

Table 1

[0192] (Manufacturing Example 2 * ) The crude product obtained in Preparation Example 1 was purified by preparative HPLC to separate oleyl amide of diethanolamine (third amide compound, component (B3)). The compositions thereof analyzed by LC-MS are shown in Table 1.

[0193] (Manufacturing Example 3 * ) To a 5L three-necked flask equipped with a distillation tube, add 5.0 mol of lauric acid and 7.5 mol of diethanolamine (hereinafter sometimes referred to as "DEA") together with a magnetic stirrer, replace the interior of the flask with nitrogen, and stir the contents of the flask with a magnetic stirrer to make a uniform mixture. While stirring the mixture in the flask with a magnetic stirrer, heat the flask in an oil bath. Slowly increase the heating temperature of the oil bath to allow water to continue to distill. Track the reaction with IR spectroscopy, and confirm the end of the reaction by IR spectroscopy after 24 hours from the start of the reaction. The heating temperature of the oil bath at the end of the reaction is 180°C. Place the contents of the cooled flask and dry under reduced pressure to obtain a crude product. The obtained crude product was purified by preparative HPLC to separate lauryl amide of diethanolamine (third amide compound, component (B3)). The compositions thereof analyzed by LC-MS are shown in Table 2.

[0194]

Table 2

[0195] (Manufacturing Example 4 * ) 2.5 mol of lauric acid, 2.5 mol of myristic acid and 10.0 mol of DEA were added to a 5L three-necked flask equipped with a distillation tube together with a magnetic stirrer, the inside of the flask was replaced with nitrogen, and the contents of the flask were stirred with a magnetic stirrer to make a uniform mixture. While stirring the mixture in the flask with a magnetic stirrer and heating the flask to 150°C in an oil bath, a rotary pump was used to reduce the pressure in the flask to maintain the pressure in the system at 20,000 Pa. After 10 hours from the start of the reaction, the pressure in the system was further reduced to 2,000 Pa and maintained. After 24 hours from the start of the reaction, the end of the reaction was confirmed by IR spectroscopy. The contents of the cooling flask were placed and dried under reduced pressure to obtain a friction modifier composition as a mixture of condensation products. Their composition analyzed by LC-MS is shown in Table 3.

[0196]

Table 3

[0197] (Production Example 5) 5.0 mol of 5,7,7-trimethyl-2-(1,3,3-trimethylbutyl)octanoic acid (in the general formula (4), k=0, R 6 =3,5,5-trimethylhexyl, R 7 =1,3,3-trimethylbutyl, R 8 = A branched fatty acid with a hydrogen atom. It is sometimes referred to as "multi-branched isostearic acid" below. ) and 7.5 mol DEA, replace the inside of the flask with nitrogen, and stir the contents of the flask with a magnetic stirrer to make a uniform mixture. While stirring the mixture in the flask with a magnetic stirrer, heat the flask in an oil bath. Slowly increase the heating temperature of the oil bath to allow water to continue to distill off. Track the reaction with IR spectroscopy, and confirm the end of the reaction by IR spectroscopy 24 hours after the start of the reaction. The heating temperature of the oil bath at the end of the reaction is 180°C. Place the contents of the cooled flask and dry under reduced pressure to obtain a crude product. The obtained crude product was purified by preparative HPLC to prepare a friction modifier composition. The compositions thereof analyzed by LC-MS are shown in Table 4.

[0198]

Table 4

[0199] (Production Example 6) The crude product obtained in Preparation Example 5 was purified by preparative HPLC to prepare a friction modifier composition having a composition different from that in Preparation Example 5. The compositions thereof analyzed by LC-MS are shown in Table 4.

[0200] (Production Example 7) 5.0 mol of 2-decyltetradecanoic acid (in the general formula (4), k=0, R 6 = dodecyl, R 7 =Decyl, R 8 = Branched chain fatty acid with hydrogen atom. ) and 7.5 mol DEA, replace the inside of the flask with nitrogen, and stir the contents of the flask with a magnetic stirrer to make a uniform mixture. While stirring the mixture in the flask with a magnetic stirrer, heat the flask in an oil bath. Slowly increase the heating temperature of the oil bath to allow water to continue to distill. Track the reaction with IR spectroscopy, and confirm the end of the reaction by IR spectroscopy after 24 hours from the start of the reaction. The heating temperature of the oil bath at the end of the reaction is 180°C. Cool the contents of the flask and dry under reduced pressure to obtain a crude product. The obtained crude product was purified by preparative HPLC to prepare a friction modifier composition. The compositions thereof analyzed by LC-MS are shown in Table 5.

[0201]

Table 5

[0202] <Examples 1 to 8 and Comparative Examples 1 to 4> As shown in Tables 6 to 8, lubricating oil compositions of the present invention (Examples 1 to 8) and comparative lubricating oil compositions (Comparative Examples 1 to 4) were prepared. In the tables, "mass %" represents mass % based on the total amount of the lubricating oil composition (100 mass %). In addition, "mass ppm" represents mass ppm based on the total amount of the lubricating oil composition, and the expression "mass ppm / X" for element X represents mass ppm as the amount of element X based on the total amount of the lubricating oil composition. The details of each component are as follows.

[0203] (A) Lubricating oil base oil: API Group II base oil (hydrocracked mineral oil base oil), kinematic viscosity (40°C): 9.3 mm 2 / s, kinematic viscosity (100℃): 2.5mm 2 / s, viscosity index: 98, saturation content: 99.9% by mass, sulfur content: less than 1 mass ppm

[0204] ((B) Friction modifier) The numbers (1 to 11) of the manufacturing examples for manufacturing each friction modifier are shown in the table. In addition, the contents of the components (B1) to (B4) converted to compounds in a state where no salt is formed are also shown in the table. Furthermore, the ratio MB2 / MB3 of the content MB2 (mass %) of the component (B2) to the content MB3 (mass %) of the component (B3) is also shown in the table (for examples other than the denominator being zero). In Examples 1 to 12 and Comparative Examples 2 to 4, the content of the friction modifier composition was adjusted so that the μ reduction rate in the LFW-1 test described below would be 20% or more.

[0205] (Other additives) (C) Metal-based detergent: calcium carbonate-overbased calcium salicylate detergent, base value 220 mgKOH / g, Ca: 8.1 mass% (D) Dispersant: Boron-containing polybutenyl succinimide dispersant, N: 1.6 mass %, B: 0.35 mass % (E) Antiwear agent: bis(3-thioundecyl) hydrogen phosphite (F) Extreme pressure agent: thiadiazole compound, S: 36 mass % (G) Antioxidant: diphenylamine antioxidant (H) Viscosity index improver: non-dispersible polymethacrylate, weight average molecular weight 35,000 Defoaming agent: dimethyl silicone

[0206]

Table 6

[0207]

Table 7

[0208]

Table 8

[0209] (LFW-1 test) For each lubricating oil composition, the friction coefficient (μ) was measured under the following conditions using a block on ring tester (LFW-1 test) described in ASTM D 2174, and the reduction rate (%) of the friction coefficient relative to Comparative Example 1 was evaluated. Test piece (ring): Falex S-10 Test Ring (SAE4620 Steal) Test piece (block): Falex H-60 ​​Test Block (SAE01 Steal) Oil temperature: 60℃ Load: 400N Circumferential speed: 1.5m / s The results are shown in Tables 6 to 8 as reduction rates (%) of the friction coefficient relative to Comparative Example 1.

[0210] (Volume resistivity) For each lubricating oil composition, the volume resistivity of the new oil was measured. The volume resistivity was measured at an oil temperature of 80°C according to the volume resistivity test specified in JIS C2101. The results are shown in Tables 6 to 8. In this test, the higher the volume resistivity, the better the electrical insulation. The volume resistivity of the new oil in this test at 80°C is preferably 2.1×10 9 Ω·cm or more.

[0211] (UNISTEEL trial) For each lubricating oil composition, the rolling fatigue life of the ball bearing was measured by the UNISTEEL test (British Institute of Petroleum method: IP305 / 79) using a UNISTEEL rolling fatigue tester (3-roll high-temperature rolling fatigue tester (TRF-1000 / 3-01H), Tokyo Test Machinery Co., Ltd.). For the test bearing, which was formed by replacing the single-side track wheel of the ball bearing (51305 manufactured by NSK) with a flat test piece (material: SUJ2), the time it took for either the ball or the test piece to reach fatigue damage was measured under the conditions of a load of 7000N, a surface pressure of 5.9GPa, a rotation speed of 1410rpm, and an oil temperature of 120°C. In addition, the vibration acceleration of the test part measured by the vibration accelerometer equipped with the UNISTEEL rolling fatigue tester reached 1.5m / s 2 When , it is determined that fatigue loss has occurred. The fatigue life is calculated as the 50% life (L50: the time when the cumulative probability is 50%) by the Weibull plot from the time when fatigue damage is reached in 10 repeated tests, and the improvement rate (%) relative to Comparative Example 1 is calculated. The results are shown in Tables 6 to 12. An improvement rate value of zero indicates no improvement in the fatigue life relative to the comparison object, and a negative improvement rate value indicates a deterioration in the fatigue life relative to the comparison object. The more positive the improvement rate of the 50% life measured in this test is, the higher the improvement effect of fatigue resistance is.

[0212] (Evaluation results) The lubricating oil compositions of Examples 1 to 8 (Tables 6 to 7) can substantially reduce the friction coefficient under conditions simulating gear lubrication while suppressing the reduction in electrical insulation, and can further substantially improve fatigue resistance, compared to the lubricating oil composition of Comparative Example 1 (Table 8) which does not contain an oiliness-based friction modifier.

[0213] The lubricating oil compositions of Comparative Examples 2 and 3 (Table 8) containing only the component (B3) as the oiliness-based friction modifier and not containing the component (B1) had a significant reduction in electrical insulation properties in order to obtain a sufficient reduction effect in the friction coefficient under conditions simulating the lubrication of gears. In addition, the fatigue resistance was not improved compared to Comparative Example 1, or was worse than that of Comparative Example 1.

[0214] Although the lubricating oil composition of Comparative Example 4 (Table 8) contains component (B1) as an oiliness-based friction modifier, the content of component (B2) relative to the content of component (B3) does not satisfy the formula (eq1). In order to obtain a sufficient effect of reducing the friction coefficient under the conditions of simulated gear lubrication, the electrical insulation is greatly reduced. In addition, no improvement in fatigue resistance is observed.

[0215] The above test results show that the lubricating oil composition according to the present invention can improve friction reduction performance, especially friction reduction performance in mixed lubrication areas (such as lubrication of gears), while suppressing the reduction of electrical insulation, and can further improve fatigue resistance.

Industrial Applicability

[0216] The lubricating oil composition of the present invention can be widely used in the lubrication field. The lubricating oil composition of the present invention contains the components (B1) and (B2) and satisfies the formula (eq1), thereby suppressing the reduction of electrical insulation, improving friction reduction performance, especially the friction reduction effect in the mixed lubrication area (such as the lubrication conditions of gears, etc.), and further improving fatigue resistance. The lubricating oil composition of the present invention exerts an improved friction reduction effect in the lubrication of metal surfaces that are easily subjected to high loads such as gears, and also exerts improved fatigue resistance. Therefore, in addition to being preferably used for the lubrication of various mechanical devices having metal surfaces that are easily subjected to high loads such as gear mechanisms, pistons, and connecting rod bearings, it can be preferably used for the lubrication of transmissions (such as manual transmissions, automatic transmissions, continuously variable transmissions, speed reducers of electric vehicles, speed increasers of wind turbines, etc.) and internal combustion engines, and can also be preferably used for lubrication of various industrial uses (such as hydraulic working oils, turbine oils, compressor oils). Furthermore, the lubricating oil composition of the present invention has improved friction reduction performance and improved fatigue resistance while suppressing the reduction of electrical insulation, so it can be preferably used as a motor oil, a transmission oil, a common lubricating oil for a motor and a transmission (gear mechanism), or a lubricating oil for an electric drive module equipped with a motor and a transmission (gear mechanism). In one embodiment, the lubricating oil composition of the present invention can be preferably used for the lubrication of a motor in a car equipped with a motor, or the lubrication of the motor and the transmission in a car equipped with a motor and a transmission (gear mechanism). In one embodiment, the lubricating oil composition of the present invention can be preferably used for cooling a cooling oil for components of an electric system such as a battery or a power electronic machine. In one embodiment, the lubricating oil composition of the present invention can be preferably used as a common lubricating / cooling oil for a transmission (gear device) or a motor or a combination thereof, a battery or one or more power electronic machines or a combination thereof. In one embodiment, the lubricating oil composition of the present invention can be preferably used as a common lubricating / cooling oil for an electric drive module equipped with a motor and a transmission (gear mechanism), a battery or one or more power electronic machines or a combination thereof.

Claims

1. A lubricating oil composition, characterized in that: contain (A) a lubricating base oil comprising one or more mineral base oils or one or more synthetic base oils or a combination thereof, (B1) one or more first amide compounds and / or salts thereof, wherein the first amide compound is a monoamide of one or more linear or branched saturated or unsaturated monovalent fatty acids (a1) having 6 to 30 carbon atoms and one or more amine compounds (a2) having no ester bond, and the amine compound (a2) is an alkanolamine oligomer having a structure formed by dehydration condensation of one or more alkanolamines (a3) ​​represented by the following general formula (1) and having a degree of polymerization of 2 or more, (B2) one or more second amide compounds, the second amide compounds having a structure in which the amino groups and one or more hydroxyl groups of one or more alkanolamines (a3) ​​represented by the following general formula (1) are acylated with the monovalent fatty acid (a1), (B3) at least one third amide compound, wherein the third amide compound is an amide of the alkanolamine (a3) ​​and the monovalent fatty acid (a1) and does not have an ester bond, (B4) at least one fourth amide compound and / or its salt, wherein the fourth amide compound has a structure in which at least one amino group and at least one hydroxyl group of the amine compound (a2) are acylated with the monovalent fatty acid (a1), The total content of the component (B1), the component (B2), the component (B3) and the component (B4) is 0.001 to 10.0% by mass based on the total amount of the composition, as calculated as the content of the compound in a state not forming a salt. The lubricating oil composition satisfies the following formula (eq1): M B2 / M B1 ≧0.50…(eq1) In formula (eq1), M B2 is the content of the component (B2) based on the total amount of the composition, M B1 is the content of the component (B1) in terms of the compound not forming a salt based on the total amount of the composition, M B2 and M B1 The units are all mass %. In the general formula (1), n ​​is 1 or 2; R 1 represents a straight-chain alkylene group having 1 to 4 carbon atoms, or a branched-chain alkylene group having 3 to 10 carbon atoms and 2 carbon atoms in the main chain; when n is 2, multiple R 1 They may be the same or different from each other.

2. The lubricating oil composition according to claim 1, wherein The content of the component (B1) is 0.005 to 10.0% by mass based on the total amount of the lubricating oil composition as calculated as the content of the compound in a non-salt state.

3. The lubricating oil composition according to claim 1 or 2, wherein Satisfies the following formula (eq2), M B2 / (M B1 +M B3 )≧0.100…(eq2) In formula (eq2), M B1 and M B2 As stated in the definition, M B3 is the content of the component (B3) based on the total amount of the composition, M B3 The unit is mass %.

4. The lubricating oil composition according to claim 1 or 2, wherein The content of the component (B2) is 8.0% by mass or more based on the total content of all acylated products of the monovalent fatty acid (a1) in the alkanolamine structure-containing compound in terms of compounds not forming salts. The hydroxyl groups in the alkanolamine structure-containing compound may be etherified.

5. The lubricating oil composition according to claim 1 or 2, wherein: The total content of all acylated products of the monovalent fatty acid (a1) in the alkanolamine structure-containing compound as unsalted compounds is 0.001 to 10.0% by mass based on the total amount of the composition. The hydroxyl groups in the alkanolamine structure-containing compound may be etherified.

6. The lubricating oil additive composition according to claim 1 or 2, wherein: The monovalent fatty acid includes one or more straight-chain fatty acids.

7. The lubricating oil additive composition according to claim 1 or 2, wherein: The monovalent fatty acid includes one or more branched-chain fatty acids.

8. The lubricating oil additive composition according to claim 7, wherein: The branched fatty acid has a tertiary carbon or a quaternary carbon atom at the alpha, beta or gamma position to the carbonyl carbon.

9. The lubricating oil composition according to claim 1 or 2, wherein: The invention further contains one or more additives selected from the group consisting of metal detergents, ashless dispersants, phosphorus-containing antiwear agents, sulfur-containing extreme pressure agents, antioxidants and viscosity index improvers.

10. The lubricating oil composition according to claim 1 or 2, wherein Its kinematic viscosity at 40°C is 4.0-50 mm 2 / s, The kinematic viscosity at 100°C is 1.0~6.9mm 2 / s.

11. The lubricating oil composition according to claim 1 or 2, which is used for lubrication of gears.

12. The lubricating oil composition according to claim 1 or 2, wherein: The lubricant is used for lubrication of the electric motor or lubrication of the electric motor and a transmission in a car equipped with the electric motor.

13. A method for lubricating an electric motor, characterized in that: The method comprises supplying the lubricating oil composition according to claim 1 or 2 to an electric motor of a vehicle equipped with the electric motor.

14. A method for lubricating an electric motor and a transmission, characterized in that: The method comprises supplying the lubricating oil composition according to claim 1 or 2 to an electric motor and a transmission of an automobile including the electric motor and the transmission.

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