Lubricant base oil

Abstract

Provided is a lubricant base oil that satisfies the following requirements (I) and (II), and that is used for cooling a device mounted on an electric vehicle and lubricating a drive mechanism. •Requirement (I): The paraffin ratio calculated from the total integrated intensity ratio (nonCH3) of CH groups and CH2 groups, calculated from a 1H-NMR spectrum measured using an NMR device, the average carbon number (Cav) measured by gas chromatography-mass spectrometry (GC-MS), and the average branch number (avB) calculated from a 13C-NMR spectrum measured using an NMR device is 0.880 or more. •Requirement (II): The ratio [avB / Cav] of the average branch number (avB) to the average carbon number (Cav) is 0.110 or less.

Description

Lubricant base oil

[0001] The present invention relates to a lubricating base oil, a lubricating oil composition containing the lubricating base oil, a method for cooling equipment using the lubricating oil composition, and a method for lubricating a drive mechanism.

[0002] In recent years, there has been a strong demand for reducing carbon dioxide emissions from the perspective of protecting the global environment. For example, in the automotive field, efforts are being made to develop fuel-efficient technologies, and hybrid and electric vehicles, which are vehicles with excellent fuel efficiency and environmental performance, are becoming more popular. Hybrid and electric vehicles are equipped with electric motors, generators, inverters, batteries, etc., and run using the power of the electric motor.

[0003] Various devices mounted on such electric vehicles require cooling because high temperatures can lead to reduced efficiency or damage. Conventional lubricating oils, such as automatic transmission fluids (ATFs) and continuously variable transmission fluids (CVTFs), are primarily used to cool devices mounted on electric vehicles, such as electric motors, generators, and batteries. Furthermore, some hybrid and electric vehicles have gear reducers, so lubricating oil compositions used therein are required to have cooling properties in addition to lubrication properties. For example, Patent Document 1 discloses a lubricating composition for cooling and / or insulating batteries or electric motors in kinetic energy recovery systems (KERS) or hybrid vehicles.

[0004] Special Publication No. 2013-522409

[0005] Meanwhile, lubricating oil compositions for cooling equipment mounted on electric vehicles, for example, are required to have not only cooling properties but also various other properties related to lubricating performance for the drive mechanisms of the equipment (e.g., viscosity characteristics, low-temperature fluidity, fuel economy), ease of handling, etc. The present invention has been made in view of these circumstances, and an object of the present invention is to provide a lubricating base oil suitable for lubricating oil compositions used for cooling equipment mounted on electric vehicles and lubricating the drive mechanisms.

[0006] The present inventors have conducted extensive research into lubricating base oils suitable for lubricating oil compositions for cooling devices and lubricating drive mechanisms mounted on electric vehicles. As a result, they have discovered that lubricating base oils adjusted to satisfy certain requirements are suitable for preparing the above-mentioned lubricating oil compositions. The present invention has been completed based on this discovery. Specifically, as one aspect of the present invention, the inventions described in the following [1] to

[21] are provided. [1] A lubricating base oil used for cooling devices and lubricating drive mechanisms mounted on electric vehicles, which satisfies the following requirements (I) to (II): Requirement (I): The paraffin ratio calculated from the following formula (i) is 0.880 or more. Formula (i): Paraffin ratio = [nonCH ３ × 3 × (avB+2) + 3 × (avB+2)] / [2 × Cav+2] In the formula (i), ３ was measured using an NMR device １ In the H-NMR spectrum, ３ The integral intensity S2 of the peak derived from the CH group or CH ２ The ratio [S1 / S2] of the integrated intensity S1 of the peak derived from the CH group and the CH ２ Cav is the average carbon number measured by gas chromatography mass spectrometry (GC / MS). avB indicates the average branch number, measured using an NMR device. １３ The total integrated intensity (a) of the terminal CH ３ The value is calculated based on the following formula (ii) from the value of the ratio [(b) / (a)] of the sum (b) of integrated intensities in the chemical shift ranges of 5.0 to 20.0 ppm and 22.45 to 22.80 ppm attributable to the CH groups. Formula (ii): avB = Cav × [(b) / (a)] - 2 Requirement (II): The ratio [avB / Cav] of the average number of branches (avB) to the average number of carbon atoms (Cav) is 0.110 or less. [2] The lubricating base oil according to the above item [1], further satisfying the following requirement (III). Requirement (III): The average number of carbon atoms (Cav) is 19.1 or more. [3] The lubricating base oil according to the above item [1] or [2], further satisfying the following requirement (IV). Requirement (IV): The ratio of the CH groups and CH２ Total integrated intensity ratio of groups (nonCH ３ ) is 2.00 or more. [4] The lubricating base oil according to any one of [1] to [3] above, wherein the average number of branches (avB) is 1.80 or more and 3.00 or less. [5] The lubricating base oil according to any one of [1] to [4] above, wherein the ratio [avB / Cav] is 0.080 or more and 0.110 or less. [6] The lubricating base oil according to any one of [1] to [5] above, wherein the lubricating base oil is a base oil obtained by refining a feedstock containing CTL oil produced from coal. [7] The lubricating base oil according to [6] above, wherein the refining treatment includes at least hydroisomerization. [8] The lubricating base oil is a refined oil of CTL oil produced from coal, and is used for cooling equipment installed in electric vehicles. [9] The kinematic viscosity at 100°C of the lubricating base oil is 1.80 mm ２ / s or more 4.30mm ２

[10] The lubricating base oil according to any one of the above [1] to [8], wherein the kinematic viscosity at 40°C of the lubricating base oil is 5.0 mm / s or less. ２ / s or more 25.0mm ２

[11] The lubricating base oil according to any one of the above [1] to [9], wherein the density of the lubricating base oil at 15°C is 0.750 g / cm or less. ３The lubricating base oil according to any one of [1] to

[10] above, wherein the lubricating base oil has a flash point of 160°C or higher.

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

[11] above, wherein the lubricating base oil has a flash point of 160°C or higher.

[13] The lubricating base oil according to any one of [1] to

[12] above, wherein the lubricating base oil has a pour point of -30.0°C or lower.

[14] The lubricating base oil according to any one of [1] to

[13] above, wherein the traction coefficient of the lubricating base oil measured under conditions of an oil temperature of 40°C, a load of 70N, an average rolling speed of 2000mm / s, and a slide-to-roll ratio of 50% is 0.0470 or lower.

[15] The lubricating base oil according to any one of [1] to

[14] above, wherein the thermal conductivity at 20°C of the lubricating base oil is 0.130 W / (m·K) or higher.

[16] A lubricating oil composition used for cooling equipment mounted on an electric vehicle and lubricating the drive mechanism, comprising the lubricating base oil according to any one of [1] to

[15] above.

[17] The lubricating oil composition according to

[16] above, further comprising one or more lubricating oil additives selected from the group consisting of pour point depressants, viscosity index improvers, antioxidants, extreme pressure agents, metal detergents, ashless dispersants, metal deactivators, corrosion inhibitors, rust inhibitors, and antifoaming agents.

[18] The lubricating oil composition according to

[17] above, wherein the total content of the lubricating oil additives is 5.0 mass% or less, based on the total amount of the lubricating oil composition.

[19] A method for cooling equipment mounted on an electric vehicle, comprising using the lubricating oil composition according to any one of

[16] to

[18] above.

[20] The method for cooling equipment according to

[19] above, wherein the equipment is at least one selected from the group consisting of a motor, a battery, an inverter, and an engine.

[21] The cooling method for equipment described in

[19] above, wherein the equipment is an equipment in which a motor and a reducer are integrated.

[0007] The lubricating base oil of a preferred embodiment of the present invention is excellent in various properties such as viscosity characteristics, low-temperature fluidity, handleability, fuel economy, and cooling properties, and can be used to prepare a lubricating oil composition having physical properties suitable for use in cooling devices mounted on electric vehicles and lubricating drive mechanisms.

[0008] The lubricating base oil (1) measured under the conditions described in this example １ 1H-NMR spectrum of lubricating base oil (1) measured under the conditions described in this example.１３ C-NMR spectrum.

[0009] For the numerical ranges described herein, the upper and lower limits can be arbitrarily combined. For example, when a numerical range is described as "preferably 30 to 100, more preferably 40 to 80," the ranges "30 to 80" and "40 to 100" are also included in the numerical ranges described herein. Furthermore, for example, when a numerical range is described as "preferably 30 or more, more preferably 40 or more, and preferably 100 or less, more preferably 80 or less," the ranges "30 to 80" and "40 to 100" are also included in the numerical ranges described herein. In addition, for example, when a numerical range described herein as "60 to 100" means a range of "60 or more (60 or more) and 100 or less (100 or less)."

[0010] [Configuration of Lubricating Base Oil] The lubricating base oil of one embodiment of the present invention is a lubricating base oil used for cooling devices mounted on electric vehicles and lubricating drive mechanisms, and satisfies the following requirements (I) to (II): Requirement (I): The paraffin ratio calculated from the following formula (i) is 0.880 or more. Formula (i): Paraffin ratio = [nonCH ３ × 3 × (avB+2) + 3 × (avB+2)] / [2 × Cav+2] In the formula (i), ３ was measured using an NMR device １ In the H-NMR spectrum, ３ The integral intensity S2 of the peak derived from the CH group or CH ２ The integral intensity S1 of the peak derived from the CH group (the integral intensity of the peak derived from the CH group and the ２ The ratio [S1 / S2] of the integrated intensity of the peaks originating from the CH group and the total integrated intensity of the peaks originating from the CH group ２ Cav is the average carbon number measured by gas chromatography mass spectrometry (GC / MS). avB indicates the average branch number, measured using an NMR device. １３The total integrated intensity (a) of the terminal CH ３ It is a value calculated based on the following formula (ii) from the ratio [(b) / (a)] of the total integrated intensity (b) of the chemical shifts attributable to the group in the ranges of 5.0 to 20.0 ppm and 22.45 to 22.80 ppm: Formula (ii): avB=Cav×[(b) / (a)]-2 Requirement (II): The ratio [avB / Cav] of the average number of branches (avB) to the average number of carbon atoms (Cav) is 0.110 or less.

[0011] In one embodiment of the present invention, the lubricating base oil preferably satisfies the above requirements (I) to (II) as well as the following requirements (III) and / or (IV): Requirement (III): The average carbon number (Cav) is 19.1 or more. Requirement (IV): The CH groups and CH ２ Total integrated intensity ratio of groups (nonCH ３ ) is 2.00 or more.

[0012] In this specification, the physical property values ​​specified in the above requirements (I) to (IV) and the physical property values ​​necessary for calculating various values ​​refer to values ​​measured and / or calculated in accordance with the methods described in the Examples below.

[0013] Equipment such as electric motors, generators, and batteries installed in electric vehicles require cooling because high temperatures can lead to a decrease in efficiency or damage. Furthermore, lubricating oil compositions used not only for cooling equipment but also for lubricating drive mechanisms are required to have properties related to the lubrication of drive mechanisms, such as viscosity characteristics, low-temperature fluidity, and fuel economy, as well as high flash point and easy handling. The lubricating oil base oil of one embodiment of the present invention is suitable for use in cooling equipment installed in electric vehicles and lubricating drive mechanisms, and can be used to prepare lubricating oil compositions having the various properties described above.

[0014] More specifically, the lubricating base oil of one embodiment of the present invention can be a lubricating base oil from which a lubricating oil composition having improved low-temperature fluidity, fuel economy, and cooling performance can be prepared by adjusting the paraffin ratio so as to satisfy requirement (I). The paraffin ratio is a value calculated from the following formula (i): Formula (i): Paraffin ratio = [nonCH ３ × 3 × (avB+2) + 3 × (avB+2)] / [2 × Cav+2] The denominator on the right side of the above formula (i) represents the total number of hydrogen atoms when it is assumed that all of the components constituting the lubricating base oil are paraffins, and is a value calculated from the average carbon number (Cav) measured by gas chromatography mass spectrometry (GC / MS). The numerator on the right side of the above formula (i) represents the total number of hydrogen atoms when it is assumed that all of the components constituting the lubricating base oil are paraffins, and is a value calculated from the average carbon number (Cav) measured by gas chromatography mass spectrometry (GC / MS). １ H-NMR, and １３ The number of hydrogen atoms in the components constituting the lubricating base oil is calculated from the measured values ​​obtained by C-NMR measurement. ２ Total integrated intensity ratio of groups (nonCH ３ ), the average carbon number (Cav), and the average branch number (avB) calculated from formula (ii). In other words, the paraffin ratio indicates the ratio of saturated aliphatic saturated hydrocarbons to all components constituting the lubricating base oil. The term "paraffin" refers to saturated aliphatic saturated hydrocarbons, and the number of carbon atoms in the saturated aliphatic saturated hydrocarbons is not limited.

[0015] In the lubricating base oil of one embodiment of the present invention, the paraffin ratio specified in requirement (I) is 0.880 or more. From the viewpoint of obtaining a lubricating base oil that can prepare a lubricating oil composition with further improved low-temperature fluidity, handleability, fuel economy, and cooling performance, the paraffin ratio may be 0.882 or more, 0.884 or more, 0.886 or more, 0.888 or more, 0.890 or more, 0.892 or more, 0.894 or more, 0.896 or more, 0.898 or more, 0.900 or more, 0.905 or more, 0.910 or more, 0.915 or more, 0.920 or more, 0.925 or more, 0.930 or more, 0.935 or more, 0.940 or more, 0.950 or more, 0.960 or more, 0.970 or more, 0.980 or more, 0.990 or more, 0.995 or more, 0.996 or more, 0.998 or more, 0.999 or more, 0.900 or more, 0.905 or more, 0.910 or more, 0.915 or more, 0.920 or more, 0.925 or more, 0.930 or more, 0.935 or more, 0.940 or more, 0.950 or more, 0.960 or more, 0.960 or more, 0.970 or more, 0.980 or more, 0.995 or more, 0.996 or more, 0.998 or more, 0.999 or more, 0.900 or more, 0.905 or more, 0. It is preferable that the molecular weight is 45 or more, 0.950 or more, 0.955 or more, 0.960 or more, 0.965 or more, 0.970 or more, 0.975 or more, 0.980 or more, 0.982 or more, 0.984 or more, 0.986 or more, or 0.988 or more, and may also be 0.999 or less, 0.998 or less, 0.997 or less, 0.996 or less, 0.995 or less, 0.994 or less, 0.993 or less, 0.992 or less, 0.991 or less, 0.990 or less, 0.988 or less, 0.980 or less, 0.970 or less, 0.960 or less, 0.950 or less, 0.940 or less, or 0.930 or less.

[0016] Furthermore, the ratio [avB / Cav] of the average branch number (avB) to the average carbon number (Cav) specified in the above requirement (II) indicates the proportion of branched structures per carbon number in the components constituting the lubricating base oil. This ratio [avB / Cav] makes it possible to specify the proportion of branched structures possessed by the components constituting the lubricating base oil, independent of the carbon number of the components constituting the lubricating base oil. By using a lubricating base oil containing components in which the proportion of branched structures per carbon number is a predetermined value or less, it is possible to obtain a lubricating base oil that can be used to prepare a lubricating oil composition that has a low traction coefficient and excellent fuel economy performance.

[0017] In the lubricating base oil of one embodiment of the present invention, the ratio [avB / Cav] specified in requirement (II) above is 0.110 or less. However, from the viewpoint of obtaining a lubricating base oil that can prepare a lubricating oil composition with further improved fuel economy and cooling performance, it is preferred that the ratio be 0.109 or less, 0.108 or less, 0.107 or less, 0.106 or less, 0.105 or less, 0.104 or less, 0.103 or less, 0.102 or less, 0.101 or less, 0.100 or less, 0.099 or less, 0.098 or less, 0.097 or less, It is preferably 0.096 or less, or 0.095 or less, and from the viewpoint of obtaining a lubricating base oil that can prepare a lubricating oil composition with improved low-temperature fluidity and handleability, it is preferably 0.080 or more, 0.081 or more, 0.082 or more, 0.083 or more, 0.084 or more, 0.085 or more, 0.086 or more, 0.087 or more, 0.088 or more, 0.089 or more, 0.090 or more, 0.091 or more, 0.092 or more, 0.093 or more, or 0.094 or more.

[0018] The average carbon number (Cav) represents the average carbon number of the components constituting the lubricating base oil. By adjusting the carbon number of the components constituting the lubricating base oil of one embodiment of the present invention so as to satisfy the above requirement (III), it is possible to obtain a lubricating base oil capable of preparing a lubricating oil composition having improved viscosity characteristics, handleability, and cooling properties. In the lubricating base oil of one embodiment of the present invention, the average carbon number (Cav) is preferably 19.1 or more from the viewpoint of obtaining a lubricating base oil capable of preparing a lubricating oil composition having improved viscosity characteristics and handleability, and further, 19.2 or more, 19.4 or more, 19.6 or more, 19.8 or more, 20.0 or more, 20.2 or more, 20.4 or more, 20.6 or more, 20.8 or more, 21.0 or more, 21.2 or more, 21.0 or more, 21.2 or more, 21.1 or more, 21.2 or more, 21.3 or more, 21.4 or more, 21.5 or more, 21.6 or more, 21.7 or more, 21.8 or more, 21.9 ...9 .4 or more, 21.6 or more, 21.8 or more, 22.0 or more, 22.2 or more, 22.4 or more, 22.6 or more, 22.8 or more, 23.0 or more, 23.2 or more, 23.4 or more, 23.6 or more, 23.8 or more, 24.0 or more, 24.2 or more, 24.4 or more, 24.6 or more, 24.8 or more, 25.0 or more, 25.5 or more, 26.0 or more, 26.5 or more, 27.0 or more, 27.5 or more, 28.0 or more, 2 From the viewpoint of obtaining a lubricating base oil capable of preparing a lubricating oil composition having good low-temperature fluidity and coolability, it is more preferable that the β-glutination coefficient be 40.0 or less, 39.5 or less, 39.0 or less, 38.5 or less, 38.0 or less, 37.5 or less, 37.0 or less, 36.5 or less, 36.0 or less, 35.5 or less, 35.0 or less, 34.5 or less, 34.0 or less, 33.5 or less, 33.0 or less. It is preferable that the average molecular weight is 32.5 or less, 32.0 or less, 31.5 or less, 31.0 or less, 30.5 or less, 30.0 or less, 29.5 or less, 29.0 or less, 28.5 or less, 28.0 or less, 27.5 or less, 27.0 or less, 26.5 or less, 26.0 or less, 25.5 or less, 25.0 or less, 24.5 or less, 24.0 or less, 23.5 or less, 23.0 or less, 22.5 or less, 22.0 or less, or 21.5 or less.

[0019] The CH group and CH ２ Total integrated intensity ratio of groups (nonCH ３) indicates the ratio of the number of hydrogen atoms in chains other than the terminals to the number of hydrogen atoms in terminal methyl groups, and is a parameter that represents the structural state such as the number of branches and chain length of the components that make up the lubricating base oil. In one embodiment of the lubricating base oil of the present invention, the CH groups and CH ２ Total integrated intensity ratio of groups (nonCH ３ By adjusting the ratio of the CH group and CH group specified in the above requirement (IV), it is possible to obtain a lubricating base oil from which a lubricating oil composition having improved viscosity characteristics, handleability, and cooling properties can be prepared. It is also possible to obtain a lubricating base oil from which a lubricating oil composition having good rubber compatibility can be prepared. In the lubricating base oil of one embodiment of the present invention, ２ Total integrated intensity ratio of groups (nonCH ３ ) is preferably 2.00 or more, more preferably 2.05 or more, 2.10 or more, 2.15 or more, 2.20 or more, 2.25 or more, 2.30 or more, 2.35 or more, 2.40 or more, 2.45 or more, 2.50 or more, 2.55 or more, 2.60 or more, 2.65 or more, 2.70 or more, 2.75 or more, 2.80 or more, 2.85 or more, 2.90 or more, 2.95 or more, 3.00 or more, 3.05 or more, or 3.10 or more, from the viewpoint of obtaining a lubricating base oil capable of preparing a lubricating oil composition having improved viscosity characteristics, handleability, cooling properties, and rubber compatibility. From the viewpoint of obtaining a lubricating base oil capable of preparing a lubricating oil composition having good thermal and cooling properties, it is preferable that the saturation temperature be 4.00 or less, 3.95 or less, 3.90 or less, 3.85 or less, 3.80 or less, 3.75 or less, 3.70 or less, 3.65 or less, 3.60 or less, 3.55 or less, 3.50 or less, 3.45 or less, 3.40 or less, 3.35 or less, 3.30 or less, 3.25 or less, 3.20 or less, 3.15 or less, 3.10 or less, 3.05 or less, 3.00 or less, 2.95 or less, 2.90 or less, 2.85 or less, 2.80 or less, 2.75 or less, 2.70 or less, 2.65 or less, or 2.60 or less.

[0020] In the lubricating base oil of one embodiment of the present invention, from the viewpoint of obtaining a lubricating base oil capable of preparing a lubricating oil composition having improved low-temperature fluidity and handleability, the average number of branches (avB) is 1.80 or more, 1.85 or more, 1.90 or more, 1.95 or more, 2.00 or more, 2.05 or more, 2.10 or more, 2.15 or more, 2.20 or more, 2.25 or more, 2.30 or more, 2.35 or more, 2.40 or more, 2.45 or more, 2.50 or more, 2.55 or more, 2.60 or more, 2.65 or more. , 2.70 or more, or 2.75 or more, and from the viewpoint of obtaining a lubricating base oil that can prepare a lubricating oil composition with good fuel economy and cooling properties, it is preferably 3.00 or less, 2.95 or less, 2.90 or less, 2.85 or less, 2.80 or less, 2.75 or less, 2.70 or less, 2.65 or less, 2.60 or less, 2.55 or less, 2.50 or less, 2.45 or less, 2.40 or less, 2.35 or less, 2.30 or less, 2.25 or less, or 2.20 or less.

[0021] [Stock Oil of Lubricating Base Oil] The lubricating base oil of one embodiment of the present invention may be a mineral base oil consisting of only one or more mineral oils, a synthetic base oil consisting of only one or more synthetic oils, or a mixed base oil consisting of one or more mineral oils and one or more synthetic oils.

[0022] Examples of mineral oils constituting the lubricating base oil of one embodiment of the present invention include atmospheric residual oils obtained by atmospheric distillation of crude oils such as paraffinic crude oil, intermediate crude oil, and naphthenic crude oil; distillates obtained by vacuum distillation of these atmospheric residual oils; and refined oils obtained by subjecting the distillates to one or more refining treatments such as solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, and hydrorefining (hydrocracking).

[0023] Examples of synthetic oils constituting the lubricating base oil of one embodiment of the present invention include poly-α-olefins such as α-olefin homopolymers or α-olefin copolymers (for example, α-olefin copolymers having 8 to 14 carbon atoms, such as ethylene-α-olefin copolymers); isoparaffins; ester-based oils such as polyol esters, dibasic acid esters, and phosphate esters; polyalkylene glycols; ether-based oils such as polyphenyl ethers; alkylbenzenes; alkylnaphthalenes; GTL (Gas To Liquids) oils produced from natural gas (for example, GTL wax produced from natural gas by the Fischer-Tropsch process); CTL (Coal to Liquid) oils produced from coal (for example, CTL oils obtained by a direct liquefaction method (such as the Bergius process) in which coal is crushed and mixed with a solvent and reacted directly with hydrogen under high temperature and pressure, and CTL waxes produced by an indirect liquefaction method (such as the Fischer-Tropsch process) in which coal is gasified once (coal gasification) and the resulting gas is separated and purified.

[0024] From the viewpoint of adjusting the lubricating base oil to satisfy the above requirements (I) to (IV) and adjusting avB in formula (ii) to the above range, such a feedstock is preferably one or more selected from a feedstock containing a petroleum-derived wax, a feedstock containing a bottom oil and a petroleum-derived wax, a GTL oil produced from natural gas, and a CTL oil produced from coal, with a GTL oil produced from natural gas or a CTL oil produced from coal being more preferred, and a CTL oil produced from coal being even more preferred. Furthermore, the lubricating base oil of one embodiment of the present invention is preferably obtained by refining such a feedstock. The refining method is preferably at least one of hydroisomerization, dewaxing, and hydrofinishing, with at least hydroisomerization being more preferred.

[0025] The lubricating base oil of another embodiment of the present invention is used for cooling equipment mounted on electric vehicles and may be a refined oil of CTL oil produced from coal, or may be a refined oil obtained by subjecting CTL oil produced from coal to hydroisomerization. The lubricating base oil of another embodiment of the present invention is used for cooling equipment mounted on electric vehicles and may be a refined oil of GTL oil produced from natural gas, or may be a refined oil obtained by subjecting GTL oil produced from natural gas to hydroisomerization. Such a lubricating base oil can be easily adjusted to satisfy the above requirements (I) to (IV).

[0026] [Examples of Preparation of Lubricating Base Oils] Lubricating base oils that satisfy the above requirements (I) to (IV) can be prepared, for example, by appropriately considering the following factors. Note that the following factors are only examples of preparation methods, and preparations can also be made by considering factors other than these.

[0027] For example, the above-mentioned feedstock oil can be refined to prepare a lubricating base oil that satisfies the above requirements (I) to (IV). The refining process preferably includes at least one of hydroisomerization, dewaxing, and hydrofinishing, and more preferably includes at least hydroisomerization. The type of refining process and refining conditions are preferably set appropriately depending on the type of feedstock oil used.

[0028] More specifically, from the viewpoint of adjusting the lubricating base oil to satisfy the above requirements (I) to (IV) and adjusting avB in formula (ii) to fall within the above range, it is preferable to select the following refining process depending on the type of feedstock used. When feedstock (A) containing bottom oil and petroleum-derived wax in the above-mentioned content ratio is used, it is preferable to subject the feedstock (A) to a refining process including at least hydroisomerization and dewaxing, and it is more preferable to subject the feedstock (A) to a refining process including hydroisomerization, dewaxing, and hydrofinishing. When feedstock (B) containing solvent-dewaxed oil is used, it is preferable to subject the feedstock (B) to a refining process including hydroisomerization, dewaxing, and hydrofinishing. When feedstock (C) containing GTL oil produced from natural gas is used, it is preferable to subject the feedstock (C) to a refining process including at least hydroisomerization. When using feedstock (iv) containing CTL oil produced from coal, it is preferable to subject the feedstock (iv) to a refining process including at least hydroisomerization.

[0029] (Hydroisomerization Treatment) Hydroisomerization treatment is a refining treatment carried out for the purposes of isomerizing linear paraffins contained in a feedstock oil into branched isoparaffins, converting aromatic components into paraffins by ring-opening, and removing impurities such as sulfur and nitrogen. Hydroisomerization treatment makes it possible to prepare a lubricating base oil that satisfies the above requirements (I) to (IV). Furthermore, hydroisomerization treatment is preferable from the viewpoint of adjusting avB in formula (ii) to fall within the above-mentioned range. Depending on the properties of the feedstock, it is preferable to perform a dewaxing treatment following hydroisomerization treatment.

[0030] The hydroisomerization treatment is preferably carried out in the presence of a hydroisomerization catalyst. Examples of the hydroisomerization catalyst include catalysts in which a metal oxide such as nickel (Ni) / tungsten (W), nickel (Ni) / molybdenum (Mo), or cobalt (Co) / molybdenum (Mo), or a noble metal such as platinum (Pt) or lead (Pd), is supported on a carrier such as silica aluminophosphate (SAPO) or zeolite. Among these, a catalyst in which platinum (Pt) is supported on silica aluminophosphate (SAPO) is preferred.

[0031] From the viewpoint of adjusting the lubricating base oil to satisfy the above requirements (I) to (IV) and from the viewpoint of adjusting avB in formula (ii) to fall within the above range, the hydrogen partial pressure in the hydroisomerization treatment is preferably 1.0 MPa or more, 1.5 MPa or more, 2.0 MPa or more, 2.5 MPa or more, 3.0 MPa or more, or 3.5 MPa or more, and is preferably 220 MPa or less, 150 MPa or less, 100 MPa or less, 50 MPa or less, 20 MPa or less, 10 MPa or less, 8.0 MPa or less, or 6.0 MPa or less.

[0032] From the viewpoint of adjusting the lubricating base oil to satisfy the above requirements (I) to (IV) and adjusting avB in formula (ii) to fall within the above range, the reaction temperature in the hydroisomerization treatment is preferably 230°C or higher, 240°C or higher, 250°C or higher, 260°C or higher, 270°C or higher, 280°C or higher, 290°C or higher, or 300°C or higher, and is preferably 480°C or lower, 420°C or lower, 400°C or lower, 370°C or lower, 350°C or lower, 330°C or lower, 320°C or lower, or 310°C or lower.

[0033] The liquid hourly space velocity (LHSV) in the hydroisomerization treatment is set to 5.0 hr / min from the viewpoint of adjusting the lubricating base oil to satisfy the above requirements (I) to (IV) and adjusting avB in the formula (ii) to fall within the above range. －１ Below, 4.0 hours －１ Below, 3.0hr －１ Below, 2.0hr －１ Below, 1.5 hours －１ Less than or equal to 1.2 hours －１From the viewpoint of improving productivity, it is preferable that the time is 0.1 hr or less. －１ More than 0.2hr －１ More than 0.3hr －１ It is preferable that the above is set.

[0034] The supply rate of hydrogen gas in the hydroisomerization treatment is preferably 100 to 1000 Nm per kiloliter of the feedstock oil. ３ , more preferably 200 to 800 Nm ３ , more preferably 250 to 650 Nm ３ is.

[0035] (Hydrofinishing Treatment) Hydrofinishing treatment is a refining treatment carried out for the purposes of completely saturating the aromatic components contained in the feedstock oil and removing impurities such as sulfur and nitrogen. By carrying out hydrofinishing treatment, it is possible to prepare a lubricating base oil that satisfies the above requirements (I) to (IV). Hydrofinishing treatment is preferably carried out in the presence of a hydrofinishing catalyst. Examples of hydrofinishing catalysts include catalysts in which metal oxides such as nickel (Ni) / tungsten (W), nickel (Ni) / molybdenum (Mo), and cobalt (Co) / molybdenum (Mo), or precious metals such as platinum (Pt) and lead (Pd), are supported on an amorphous support such as silica / alumina or alumina, or a crystalline support such as zeolite.

[0036] From the viewpoint of adjusting the lubricating base oil to satisfy the above requirements (I) to (IV), the hydrogen partial pressure in the hydrofinishing treatment is preferably 5 MPa or more, 7 MPa or more, 10 MPa or more, 12 MPa or more, 16 MPa or more, 18 MPa or more, or 20 MPa or more, and may also be 30 MPa or less, 25 MPa or less, or 20 MPa or less.

[0037] From the viewpoint of adjusting the lubricating base oil to satisfy the above requirements (I) to (IV), the reaction temperature in the hydrofinishing treatment is preferably 200°C or higher, 220°C or higher, 240°C or higher, 260°C or higher, or 280°C or higher, and is preferably 400°C or lower, 350°C or lower, or 330°C or lower.

[0038] The liquid hourly space velocity (LHSV) in the hydrofinishing treatment is set to 5.0 hr from the viewpoint of adjusting the lubricating base oil to satisfy the above requirements (I) to (IV). －１ Below, 4.0 hours －１ Below, 3.0hr －１ Below, 2.0hr －１ Below, 1.5 hours －１ Less than or equal to 1.2 hours －１ From the viewpoint of improving productivity, it is preferable that the time is 0.1 hr or less. －１ More than 0.2hr －１ More than 0.3hr －１ It is preferable that the above is set.

[0039] The supply rate of hydrogen gas in the hydrofinishing treatment is preferably 100 to 1000 Nm per kiloliter of the feed oil to be treated. ３ , more preferably 200 to 800 Nm ３ , more preferably 250 to 650 Nm ３ is.

[0040] By subjecting the hydrofinishing-treated product oil to vacuum distillation under appropriately set conditions (pressure, temperature, time, etc.), it is possible to obtain a lubricating base oil having a predetermined kinematic viscosity and satisfying the above requirements (I) to (IV).

[0041] [Various Properties of Lubricating Base Oil] The kinematic viscosity at 40°C of the lubricating base oil of one embodiment of the present invention is 5.0 mmHg, from the viewpoint of improving viscosity characteristics and adjusting the lubricating base oil to a high flash point. ２ / s or more, 5.2mm ２ / s or more, 5.4mm ２ / s or more, 5.6mm ２ / s or more, 5.8mm ２ / s or more, 6.0mm ２ / s or more, 6.2mm ２ / s or more, 6.4mm ２ / s or more, 6.6mm ２ / s or more, 6.8mm ２ / s or more, 7.0mm ２ / s or more, 7.5mm ２ / s or more, 8.0mm ２ / s or more, 8.5mm ２ / s or more, 9.0mm ２ / s or more, 9.5mm ２ / s or more, 10.0mm ２ / s or more, 10.5mm ２ / s or more, 11.0mm ２ / s or more, 11.5mm ２ / s or more, 12.0mm ２ / s or more, 12.5mm ２ / s or more, 13.0mm ２ / s or more, 13.5mm ２ / s or more, 14.0mm ２ / s or more, 14.5mm ２ / s or more, 15.0mm ２ / s or more, 15.5mm ２ / s or more, 16.0mm ２ / s or more, 16.5mm ２ / s or more, 17.0mm ２ / s or more, or 17.5 mm ２ / s or more, and from the viewpoint of providing a lubricating base oil from which a lubricating oil composition having good viscosity characteristics and cooling properties can be prepared, ２ / s or less, 24.5mm ２ / s or less, 24.0mm ２ / s or less, 23.5mm ２ / s or less, 23.0mm ２ / s or less, 22.5mm ２ / s or less, 22.0mm ２ / s or less, 21.5mm ２ / s or less, 21.0mm ２ / s or less, 20.5mm ２ / s or less, 20.0mm ２ / s or less, 19.5mm ２ / s or less, 19.0mm ２ / s or less, 18.5mm ２ / s or less, 18.0mm ２ / s or less, 17.5mm ２ / s or less, 17.0mm ２ / s or less, 16.5mm ２ / s or less, 16.0mm ２ / s or less, 15.5mm ２ / s or less, 15.0mm ２ / s or less, 14.5mm２ / s or less, 14.0mm ２ / s or less, 13.5mm ２ / s or less, 13.0mm ２ / s or less, 12.5mm ２ / s or less, 12.0mm ２ / s or less, 11.5mm ２ / s or less, 11.0mm ２ / s or less, 10.5mm ２ / s or less, 10.0mm ２ / s or less, 9.5mm ２ / s or less, 9.0mm ２ / s or less, 8.5mm ２ / s or less, 8.0mm ２ / s or less, 7.5mm ２ / s or less, or 7.0 mm ２ It is preferable to set it to / s or less.

[0042] The kinematic viscosity at 100°C of the lubricating base oil of one embodiment of the present invention is 1.80 mm from the viewpoint of improving viscosity characteristics and adjusting the lubricating base oil to a high flash point. ２ / s or more, 1.85mm ２ / s or more, 1.90mm ２ / s or more, 1.95mm ２ / s or more, 2.00mm ２ / s or more, 2.05mm ２ / s or more, 2.10mm ２ / s or more, 2.15mm ２ / s or more, 2.20mm ２ / s or more, 2.25mm ２ / s or more, 2.30mm ２ / s or more, 2.35mm ２ / s or more, 2.40mm ２ / s or more, 2.45mm ２ / s or more, 2.50mm ２ / s or more, 2.55mm ２ / s or more, 2.60mm ２ / s or more, 2.65mm ２ / s or more, 2.70mm ２ / s or more, 2.75mm ２ / s or more, 2.80mm ２ / s or more, 2.85mm ２ / s or more, 2.90mm２ / s or more, 2.95mm ２ / s or more, 3.00mm ２ / s or more, 3.05mm ２ / s or more, 3.10mm ２ / s or more, 3.20mm ２ / s or more, 3.30mm ２ / s or more, 3.40mm ２ / s or more, 3.50mm ２ / s or more, 3.60mm ２ / s or more, 3.70mm ２ / s or more, 3.80mm ２ / s or more, 3.90mm ２ / s or more, 4.00mm ２ / s or more, or 4.10 mm ２ / s or more, and from the viewpoint of providing a lubricating base oil from which a lubricating oil composition having good viscosity characteristics and cooling properties can be prepared, ２ / s or less, 4.25mm ２ / s or less, 4.20mm ２ / s or less, 4.15mm ２ / s or less, 4.10mm ２ / s or less, 4.05mm ２ / s or less, 4.00mm ２ / s or less, 3.95mm ２ / s or less, 3.90mm ２ / s or less, 3.85mm ２ / s or less, 3.80mm ２ / s or less, 3.75mm ２ / s or less, 3.70mm ２ / s or less, 3.65mm ２ / s or less, 3.60mm ２ / s or less, 3.55mm ２ / s or less, 3.50mm ２ / s or less, 3.45mm ２ / s or less, 3.40mm ２ / s or less, 3.35mm ２ / s or less, 3.30mm ２ / s or less, 3.25mm ２ / s or less, 3.20mm ２ / s or less, 3.15mm ２ / s or less, 3.10mm ２ / s or less, 3.05mm ２ / s or less, 3.00mm ２ / s or less, 2.90mm ２ / s or less, 2.80mm ２ / s or less, 2.70mm ２ / s or less, 2.60mm ２ / s or less, 2.50mm ２ / s or less, 2.40mm ２ / s or less, 2.30mm ２ / s or less, or 2.20 mm ２ It is preferable to set the value to / s or less.

[0043] From the viewpoint of preparing a lubricating oil composition having good viscosity characteristics, the viscosity index of the lubricating base oil of one embodiment of the present invention is 70 or more, 80 or more, 90 or more, 95 or more, 100 or more, 105 or more, 110 or more, 112 or more, 114 or more, 116 or more, 118 or more, 120 or more, 122 or more, 124 or more, 126 or more, 128 or more, 130 or more, 132 or more, 134 or more, or 136 or more is preferable, and may also be 250 or less, 240 or less, 230 or less, 220 or less, 210 or less, 200 or less, 190 or less, 180 or less, 170 or less, 160 or less, 150 or less, 140 or less, 135 or less, 130 or less, 125 or less, 120 or less, or 115 or less.

[0044] In this specification, the kinematic viscosity and viscosity index refer to values ​​measured and calculated in accordance with JIS K2283:2000.

[0045] The density of the lubricating base oil of one embodiment of the present invention at 15 ° C. is 0.750 g / cm ３ Above, 0.755g / cm ３ Above, 0.760g / cm ３ Above, 0.765g / cm ３ Above, 0.770g / cm ３ Above, 0.775g / cm ３ Above, 0.780g / cm ３ Above, 0.785g / cm ３ Above, 0.790g / cm ３ Above, 0.795g / cm ３ Above, 0.800g / cm ３Above, 0.805g / cm ３ Above, 0.810g / cm ３ or more, or 0.815 g / cm ３ It is preferable that the density is 1.10 g / cm or more. ３ Below, 1.00g / cm ３ Below, 0.990g / cm ３ Below, 0.980g / cm ３ Below, 0.970g / cm ３ Below, 0.960g / cm ３ Below, 0.950g / cm ３ Below, 0.940g / cm ３ Below, 0.930g / cm ３ Below, 0.920g / cm ３ Below, 0.910g / cm ３ or less, or 0.900 g / cm ３ Below, 0.890g / cm ３ Below, 0.880g / cm ３ Below, 0.870g / cm ３ Below, 0.860g / cm ３ Below, 0.850g / cm ３ Below, 0.840g / cm ３ Below, 0.830g / cm ３ or less, or 0.820 g / cm ３ In this specification, the density refers to a value measured in accordance with JIS K2249.

[0046] From the viewpoint of providing a lubricating mineral oil that is excellent in safety and can be adjusted to a lubricating oil composition with good handleability, the flash point of the lubricating base oil of one embodiment of the present invention is 160°C or higher, 162°C or higher, 164°C or higher, 166°C or higher, 168°C or higher, 170°C or higher, 172°C or higher, 174°C or higher, 176°C or higher, 178°C or higher, 180°C or higher, 182°C or higher, 184°C or higher, 186°C or higher, 188°C or higher, 190°C or higher, 192°C or higher, 194°C or higher, It is preferably 196°C or higher, 198°C or higher, 200°C or higher, 202°C or higher, 204°C or higher, 206°C or higher, 208°C or higher, 210°C or higher, 212°C or higher, 214°C or higher, 216°C or higher, or 218°C or higher, and may be 400°C or lower, 390°C or lower, 380°C or lower, 370°C or lower, 360°C or lower, 350°C or lower, 340°C or lower, 330°C or lower, 320°C or lower, 310°C or lower, or 300°C or lower. In this specification, the flash point refers to a value measured by the Pensky-Martens closed-cell method (PM method) in accordance with JIS K2265-3:2007.

[0047] From the viewpoint of preparing a lubricating oil composition having good low-temperature fluidity, the pour point of the lubricating base oil of one embodiment of the present invention is -30.0 ° C. or less, -32.5 ° C. or less, -35.0 ° C. or less, -37.5 ° C. or less, -40.0 ° C. or less, -42.5 ° C. or less, -45.0 ° C. or less, -47.5 ° C. or less, -50.0 ° C. or less, -52.5 ° C. or less, -55.0 ° C. or less, -57.5 ° C. or less, -60.0 ° C. or less, or preferably less than -60.0 ° C. In this specification, pour point means a value measured in accordance with JIS K2269:1987 (Test method for pour point and cloud point of crude oil and petroleum products).

[0048] The traction coefficient of the lubricating base oil of one embodiment of the present invention, measured under conditions of an oil temperature of 40 ° C., a load of 70 N, an average rolling speed of 2000 mm / s, and a slide-to-roll ratio of 50%, is preferably 0.0470 or less, 0.0468 or less, 0.0466 or less, 0.0464 or less, 0.0462 or less, 0.0460 or less, 0.0458 or less, 0.0456 or less, 0.0454 or less, 0.0452 or less, 0.0450 or less, 0.0448 or less, 0.0446 or less, 0.0444 or less, 0.0442 or less, 0.0440 or less, 0.0438 or less, 0.0436 or less, 0.0434 or less, or 0.0432 or less. The lower the traction coefficient value, the more excellent the lubricating base oil's fuel economy. In this specification, the traction coefficient is a value measured under conditions of an oil temperature of 40°C, a load of 70 N, an average rolling speed of 2000 mm / s, and a slide-to-roll ratio (SRR) of 50%, and specifically means a value measured by the method described in the examples.

[0049] The thermal conductivity at 20 ° C. of the lubricating base oil of one embodiment of the present invention is 0.130 W / (m K) or more, 0.132 W / (m K) or more, 0.134 W / (m K) or more, 0.136 W / (m K) or more, 0.138 W / (m K) or more, 0.140 W / (m K) or more, 0.142 W / (m K) or more, 0.144 W / (m K) or more, 0.146 W / (m K) or more, or 0.148 W / (m K) or more is preferable.

[0050] The thermal conductivity at 50 ° C. of the lubricating base oil of one embodiment of the present invention is 0.120 W / (m K) or more, 0.122 W / (m K) or more, 0.124 W / (m K) or more, 0.126 W / (m K) or more, 0.128 W / (m K) or more, 0.130 W / (m K) or more, 0.132 W / (m K) or more, 0.134 W / (m K) or more, 0.136 W / (m K) or more, 0.138 W / (m K) or more, 0.140 W / (m K) or more, 0.142 W / (m K) or more, or 0.144 W / (m K) or more is preferable.

[0051] The thermal conductivity at 100 ° C. of the lubricating base oil of one embodiment of the present invention is 0.110 W / (m K) or more, 0.112 W / (m K) or more, 0.114 W / (m K) or more, 0.116 W / (m K) or more, 0.118 W / (m K) or more, 0.120 W / (m K) or more, 0.122 W / (m K) or more, 0.124 W / (m K) or more, 0.126 W / (m K) or more, 0.128 W / (m K) or more, 0.130 W / (m K) or more, 0.132 W / (m K) or more, 0.134 W / (m K) or more, or 0.136 W / (m K) or more is preferable.

[0052] The higher the thermal conductivity, the better the cooling ability of the lubricating base oil. In this specification, thermal conductivity refers to a value measured in accordance with ASTM D7896-19.

[0053] The volume resistivity of the lubricating base oil of one embodiment of the present invention measured under conditions of 80 ° C. and 250 V / mm is, from the viewpoint of being a lubricating base oil capable of preparing a lubricating oil composition having high insulating properties, 1.0 TΩ m or more, 5.0 TΩ m or more, 10.0 TΩ m or more, 15.0 TΩ m or more, 20.0 TΩ m or more, 25.0 TΩ m or more, 30.0 TΩ m or more, 40.0 TΩ m or more, 50.0 TΩ m or more, 60.0 TΩ m or more, 70.0 TΩ m or more, 80.0 TΩ m or more, 90.0 TΩ m or more, or 100.0 TΩ m or more. The higher the volume resistivity, the more excellent the insulating properties of the lubricating base oil. In this specification, volume resistivity means a value measured in accordance with JIS C2101:1999 under conditions of a measurement temperature of 80 ° C. and an applied voltage of 250 V.

[0054] [Constitution of Lubricating Oil Composition] A lubricating oil composition according to one embodiment of the present invention comprises the lubricating oil base oil according to one embodiment of the present invention described above. The lubricating oil composition according to one embodiment of the present invention can be suitably used for cooling equipment mounted on electric vehicles and lubricating the drive mechanisms. The lubricating oil composition according to one embodiment of the present invention may further contain lubricating oil additives. Specifically, the lubricating oil composition may contain one or more lubricating oil additives selected from pour point depressants, viscosity index improvers, antioxidants, extreme pressure agents, metal detergents, ashless dispersants, metal deactivators, corrosion inhibitors, rust inhibitors, and antifoaming agents, or may not contain these lubricating oil additives. Furthermore, the lubricating oil composition according to one embodiment of the present invention may or may not contain a friction modifier (e.g., an organic molybdenum friction modifier, etc.). These lubricating oil additives may be used alone or in combination of two or more.

[0055] The content of each of these lubricating oil additives can be adjusted appropriately within a range that does not impair the effects of the present invention, and may be, based on the total amount (100 mass%) of the lubricating oil composition, independently for each additive, 0.001 mass% or more, 0.005 mass% or more, 0.01 mass% or more, 0.05 mass% or more, 0.1 mass% or more, 0.5 mass% or more, 1.0 mass% or more, 1.5 mass% or more, or 2.0 mass% or more, or may be less than 15.0 mass%, less than 10.0 mass%, less than 8.0 mass%, less than 6.0 mass%, less than 5.0 mass%, less than 4.0 mass%, less than 3.0 mass%, less than 2.0 mass%, less than 1.0 mass%, less than 0.10 mass%, less than 0.01 mass%, less than 0.001 mass%, or less than 0.0001 mass%.

[0056] In the lubricating oil composition of one embodiment of the present invention, the total content of the lubricating oil additives may be 50.0 mass% or less, 45.0 mass% or less, 40.0 mass% or less, 35.0 mass% or less, 30.0 mass% or less, 25.0 mass% or less, 20.0 mass% or less, 15.0 mass% or less, 10.0 mass% or less, 5.0 mass% or less, 4.0 mass% or less, 3.0 mass% or less, 2.0 mass% or less, 1.0 mass% or less, 0.1 mass% or less, or 0.01 mass% or less, based on the total amount (100 mass%) of the lubricating oil composition.

[0057] In the lubricating oil composition of one embodiment of the present invention, the content of the lubricating base oil of one embodiment of the present invention described above is preferably 50.0 mass% or more, 60.0 mass% or more, 70.0 mass% or more, 80.0 mass% or more, 85.0 mass% or more, 90.0 mass% or more, 95.0 mass% or more, 96.0 mass% or more, 97.0 mass% or more, 98.0 mass% or more, or 99.0 mass% or more, based on the total amount (100 mass%) of the lubricating oil composition.

[0058] <Pour Point Depressant> Examples of pour point depressants used in one embodiment of the present invention include ethylene-vinyl acetate copolymers, condensates of chlorinated paraffin and naphthalene, condensates of chlorinated paraffin and phenol, polymethacrylates, polyalkylstyrenes, etc. These pour point depressants may be used alone or in combination of two or more.

[0059] <Viscosity Index Improver> Examples of viscosity index improvers used in one embodiment of the present invention include polymers such as non-dispersant polymethacrylate, dispersant polymethacrylate, olefin copolymers (e.g., ethylene-propylene copolymers, etc.), dispersant olefin copolymers, and styrene copolymers (e.g., styrene-diene copolymers, styrene-isoprene copolymers, etc.). These viscosity index improvers may be used alone or in combination of two or more. The weight average molecular weight (Mw) of the viscosity index improver used in one embodiment of the present invention may be 5,000 or more, 7,000 or more, 10,000 or more, 15,000 or more, or 20,000 or more, or may be 1,000,000 or less, 700,000 or less, 500,000 or less, 300,000 or less, 200,000 or less, 100,000 or less, or 50,000 or less.

[0060] <Antioxidant> Examples of antioxidants used in one embodiment of the present invention include amine-based antioxidants such as alkylated diphenylamine, phenylnaphthylamine, and alkylated phenylnaphthylamine; and phenol-based antioxidants such as 2,6-di-t-butylphenol, 4,4'-methylenebis(2,6-di-t-butylphenol), isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, and n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate. These antioxidants may be used alone or in combination of two or more. In the lubricating oil composition of one embodiment of the present invention, it is preferable to use an amine-based antioxidant and a phenol-based antioxidant in combination.

[0061] <Extreme Pressure Agents (Antiwear Agents)> Examples of the extreme pressure agents (antiwear agents) used in one embodiment of the present invention include sulfur-containing compounds such as zinc dithiophosphate; phosphorus-containing compounds such as phosphites, phosphate esters, phosphonate esters, and their amine salts or metal salts; and sulfur- and phosphorus-containing compounds such as thiophosphites, thiophosphate esters, thiophosphonate esters, and their amine salts or metal salts. These extreme pressure agents may be used alone or in combination of two or more. Note that the lubricating oil composition of one embodiment of the present invention may have a limited content of extreme pressure agents (antiwear agents), or may be substantially free of extreme pressure agents (antiwear agents). In the lubricating oil composition of this embodiment, the content of the extreme pressure agents (antiwear agents) may be less than 0.1 mass%, less than 0.01 mass%, less than 0.001 mass%, less than 0.0001 mass%, or less than 0.00001 mass%, based on the total amount (100 mass%) of the lubricating oil composition. The lubricating oil composition of one embodiment of the present invention may have a limited zinc dithiophosphate content, or may be substantially free of zinc dithiophosphate. In the lubricating oil composition of this embodiment, the content of zinc dithiophosphate, calculated as zinc atoms, may be less than 100 ppm by mass, less than 50 ppm by mass, less than 20 ppm by mass, less than 10 ppm by mass, less than 2.0 ppm by mass, less than 1.0 ppm by mass, less than 100 ppb by mass, less than 10 ppb by mass, less than 1.0 ppb by mass, or less than 0.1 ppb by mass, based on the total amount (100% by mass) of the lubricating oil composition. In this specification, the zinc atom content refers to a value measured in accordance with JPI-5S-38-92.

[0062] <Fatty Acid Amide> The lubricating oil composition of one embodiment of the present invention may contain a fatty amide from the viewpoint of imparting a friction-reducing effect, and the content of the fatty amide may be limited from the viewpoint of suppressing a decrease in insulating properties. In the lubricating oil composition of one embodiment of the present invention, from the viewpoint of suppressing a decrease in insulating properties, the content of the fatty amide may be less than 1.0 mass%, less than 0.5 mass%, less than 0.1 mass%, less than 0.01 mass%, less than 0.001 mass%, less than 0.0001 mass%, or less than 0.00001 mass%, based on the total amount (100 mass%) of the lubricating oil composition.

[0063] Examples of aliphatic amides include reaction products of aliphatic carboxylic acids and aliphatic amines. Examples of aliphatic carboxylic acids include palmitic acid, isopalmitic acid, stearic acid, isostearic acid, behenic acid, lignoceric acid, cetyronic acid, heptacosanoic acid, montanic acid, melissic acid, lacteric acid, cetoleic acid, and erucic acid. Examples of aliphatic amines include ammonia, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

[0064] <Metallic Detergent> Examples of metallic detergents used in one embodiment of the present invention include metal salts such as metal sulfonates, metal salicylates, and metal phenates. The metal atoms constituting the metal salts are preferably metal atoms selected from alkali metals and alkaline earth metals, more preferably sodium, calcium, magnesium, or barium, and even more preferably calcium. These metallic detergents may be used alone or in combination of two or more.

[0065] In the lubricating oil composition of one embodiment of the present invention, the metallic detergent preferably comprises one or more selected from calcium sulfonate, calcium salicylate, and calcium phenate, and more preferably comprises calcium sulfonate. The calcium sulfonate content is preferably 50 to 100 mass%, more preferably 60 to 100 mass%, even more preferably 70 to 100 mass%, and still more preferably 80 to 100 mass%, based on the total amount (100 mass%) of metallic detergents contained in the lubricating oil composition.

[0066] The base number of the metallic detergent is preferably 0 to 600 mgKOH / g. However, in the lubricating oil composition of one embodiment of the present invention, the metallic detergent is preferably an overbased metallic detergent having a base number of 100 mgKOH / g or more. The base number of the overbased metallic detergent is 100 mgKOH / g or more, preferably 150 to 500 mgKOH / g, and more preferably 200 to 450 mgKOH / g. In this specification, "base number" refers to the base number measured by the perchloric acid method in accordance with JIS K2501:2003 "Petroleum Products and Lubricants - Neutralization Number Test Method" 9. The lubricating oil composition of one embodiment of the present invention may limit the content of metallic detergents such as calcium-based detergents, magnesium-based detergents, and sodium-based detergents, or may be substantially free of metallic detergents. In the lubricating oil composition of this embodiment, the content of the metallic detergent converted into alkali metal atoms or alkaline earth metal atoms (such as calcium atoms, magnesium atoms, or sodium atoms) may be less than 1000 ppm by mass, less than 700 ppm by mass, less than 500 ppm by mass, less than 300 ppm by mass, less than 200 ppm by mass, less than 100 ppm by mass, less than 70 ppm by mass, less than 50 ppm by mass, less than 20 ppm by mass, less than 10 ppm by mass, less than 2.0 ppm by mass, less than 1.0 ppm by mass, less than 100 ppb by mass, less than 10 ppb by mass, less than 1.0 ppb by mass, or 0.1 ppb by mass, based on the total amount (100% by mass) of the lubricating oil composition. In this specification, the content of alkali metal atoms such as calcium atoms, magnesium atoms, or sodium atoms, or alkaline earth metal atoms, and zinc atoms means the value measured in accordance with JPI-5S-38-92.

[0067] <Ashless Dispersant> Examples of the ashless dispersant used in one embodiment of the present invention include boron-free succinimides such as boron-free alkenyl succinimides, boron-containing succinimides such as boron-containing alkenyl succinimides, benzylamines, boron-containing benzylamines, succinic acid esters, fatty acids, and mono- or di-carboxylic acid amides represented by succinic acid, etc. These ashless dispersants may be used alone or in combination of two or more.

[0068] <Metal Deactivator> Examples of the metal deactivator used in one embodiment of the present invention include benzotriazole-based compounds, tolyltriazole-based compounds, imidazole-based compounds, thiadiazole-based compounds, pyrimidine-based compounds, etc. These metal deactivators may be used alone or in combination of two or more.

[0069] <Corrosion inhibitor> Examples of the corrosion inhibitor used in one embodiment of the present invention include amine compounds, alkanolamine compounds, amide compounds, carboxylic acid compounds, etc. These corrosion inhibitors may be used alone or in combination of two or more.

[0070] <Rust inhibitor> Examples of the rust inhibitor used in one embodiment of the present invention include fatty acids, alkenyl succinic acid half esters, fatty acid soaps, alkyl sulfonates, polyhydric alcohol fatty acid esters, fatty acid amines, oxidized paraffins, alkyl polyoxyethylene ethers, etc. These rust inhibitors may be used alone or in combination of two or more.

[0071] <Antifoaming Agent> Examples of antifoaming agents used in one embodiment of the present invention include silicone oil, fluorosilicone oil, fluoroalkyl ether, etc. These antifoaming agents may be used alone or in combination of two or more.

[0072] <Friction Modifier> The lubricating oil composition of one embodiment of the present invention may further contain a friction modifier. The friction modifier may be used alone or in combination of two or more. Examples of the friction modifier used in one embodiment of the present invention include molybdenum-based friction modifiers such as molybdenum dithiocarbamate (MoDTC), molybdenum dithiophosphate (MoDTP), and amine salts of molybdenum acid; ashless friction modifiers such as aliphatic amines, fatty acid esters, fatty acid amides, fatty acids, fatty alcohols, and aliphatic ethers, each having at least one alkyl or alkenyl group having 6 to 30 carbon atoms in the molecule; oils and fats, amines, amides, and sulfurized esters.

[0073] The lubricating oil composition of one embodiment of the present invention may have a limited content of the molybdenum-based compounds, or may be substantially free of molybdenum-based compounds. In the lubricating oil composition of this embodiment, the content of molybdenum atoms derived from the molybdenum-based compounds may be less than 100 ppm by mass, less than 50 ppm by mass, less than 20 ppm by mass, less than 10 ppm by mass, less than 2.0 ppm by mass, less than 1.0 ppm by mass, less than 100 ppb by mass, less than 10 ppb by mass, less than 1.0 ppb by mass, or less than 0.1 ppb by mass, based on the total amount (100% by mass) of the lubricating oil composition. In this specification, the molybdenum atom content refers to a value measured in accordance with JPI-5S-38-92.

[0074] [Properties of Lubricating Oil Composition] The kinematic viscosity of the lubricating oil composition of one embodiment of the present invention at 40°C is 5.0 mm ２ / s or more, 5.2mm ２ / s or more, 5.4mm ２ / s or more, 5.6mm ２ / s or more, 5.8mm ２ / s or more, 6.0mm ２ / s or more, 6.2mm ２ / s or more, 6.4mm ２ / s or more, 6.6mm ２ / s or more, 6.8mm ２ / s or more, 7.0mm ２ / s or more, 7.5mm ２ / s or more, 8.0mm ２ / s or more, 8.5mm ２ / s or more, 9.0mm ２ / s or more, 9.5mm ２ / s or more, 10.0mm ２ / s or more, 10.5mm ２ / s or more, 11.0mm ２ / s or more, 11.5mm ２ / s or more, 12.0mm ２ / s or more, 12.5mm ２ / s or more, 13.0mm ２ / s or more, 13.5mm ２ / s or more, 14.0mm ２ / s or more, 14.5mm ２ / s or more, 15.0mm ２ / s or more, 15.5mm ２ / s or more, 16.0mm ２ / s or more, 16.5mm ２ / s or more, 17.0mm ２ / s or more, or 17.5 mm ２ / s or more, and ２ / s or less, 24.5mm ２ / s or less, 24.0mm ２ / s or less, 23.5mm ２ / s or less, 23.0mm ２ / s or less, 22.5mm ２ / s or less, 22.0mm ２ / s or less, 21.5mm ２ / s or less, 21.0mm ２ / s or less, 20.5mm ２ / s or less, 20.0mm ２ / s or less, 19.5mm ２ / s or less, 19.0mm ２ / s or less, 18.5mm ２ / s or less, 18.0mm ２ / s or less, 17.5mm ２ / s or less, 17.0mm ２ / s or less, 16.5mm ２ / s or less, 16.0mm ２ / s or less, 15.5mm ２ / s or less, 15.0mm ２ / s or less, 14.5mm ２ / s or less, 14.0mm ２ / s or less, 13.5mm ２ / s or less, 13.0mm ２ / s or less, 12.5mm ２ / s or less, 12.0mm ２ / s or less, 11.5mm ２ / s or less, 11.0mm ２ / s or less, 10.5mm ２ / s or less, 10.0mm ２ / s or less, 9.5mm ２ / s or less, 9.0mm ２ / s or less, 8.5mm ２ / s or less, 8.0mm ２ / s or less, 7.5mm ２ / s or less, or 7.0 mm ２ / s or less.

[0075] The lubricating oil composition of one embodiment of the present invention has a kinematic viscosity at 100°C of 1.80 mm ２ / s or more, 1.85mm ２ / s or more, 1.90mm ２ / s or more, 1.95mm ２ / s or more, 2.00mm ２ / s or more, 2.05mm ２ / s or more, 2.10mm ２ / s or more, 2.15mm ２ / s or more, 2.20mm ２ / s or more, 2.25mm ２ / s or more, 2.30mm ２ / s or more, 2.35mm ２ / s or more, 2.40mm ２ / s or more, 2.45mm ２ / s or more, 2.50mm ２ / s or more, 2.55mm ２ / s or more, 2.60mm ２ / s or more, 2.65mm ２ / s or more, 2.70mm ２ / s or more, 2.75mm ２ / s or more, 2.80mm ２ / s or more, 2.85mm ２ / s or more, 2.90mm ２ / s or more, 2.95mm ２ / s or more, 3.00mm ２ / s or more, 3.05mm ２ / s or more, 3.10mm ２ / s or more, 3.20mm ２ / s or more, 3.30mm ２ / s or more, 3.40mm ２ / s or more, 3.50mm ２ / s or more, 3.60mm ２ / s or more, 3.70mm ２ / s or more, 3.80mm ２ / s or more, 3.90mm ２ / s or more, 4.00mm ２ / s or more, or 4.10 mm ２ / s or more, and 4.30 mm２ / s or less, 4.25mm ２ / s or less, 4.20mm ２ / s or less, 4.15mm ２ / s or less, 4.10mm ２ / s or less, 4.05mm ２ / s or less, 4.00mm ２ / s or less, 3.95mm ２ / s or less, 3.90mm ２ / s or less, 3.85mm ２ / s or less, 3.80mm ２ / s or less, 3.75mm ２ / s or less, 3.70mm ２ / s or less, 3.65mm ２ / s or less, 3.60mm ２ / s or less, 3.55mm ２ / s or less, 3.50mm ２ / s or less, 3.45mm ２ / s or less, 3.40mm ２ / s or less, 3.35mm ２ / s or less, 3.30mm ２ / s or less, 3.25mm ２ / s or less, 3.20mm ２ / s or less, 3.15mm ２ / s or less, 3.10mm ２ / s or less, 3.05mm ２ / s or less, 3.00mm ２ / s or less, 2.90mm ２ / s or less, 2.80mm ２ / s or less, 2.70mm ２ / s or less, 2.60mm ２ / s or less, 2.50mm ２ / s or less, 2.40mm ２ / s or less, 2.30mm ２ / s or less, and 2.20mm ２ / sThe following としてもよい.

[0076] The viscosity index of the lubricating oil composition of one embodiment of the present invention is preferably 70 or more, 80 or more, 90 or more, 95 or more, 100 or more, 105 or more, 110 or more, 112 or more, 114 or more, 116 or more, 118 or more, 120 or more, 122 or more, 124 or more, 126 or more, 128 or more, 130 or more, 132 or more, 134 or more, or 136 or more, and may be 250 or less, 240 or less, 230 or less, 220 or less, 210 or less, 200 or less, 190 or less, 180 or less, 170 or less, 160 or less, 150 or less, 140 or less, 135 or less, 130 or less, 125 or less, 120 or less, or 115 or less.

[0077] The flash point of the lubricating oil composition of one embodiment of the present invention may be 160°C or higher, 162°C or higher, 164°C or higher, 166°C or higher, 168°C or higher, 170°C or higher, 172°C or higher, 174°C or higher, 176°C or higher, 178°C or higher, 180°C or higher, 182°C or higher, 184°C or higher, 186°C or higher, 188°C or higher, 190°C or higher, 192°C or higher, 194°C or higher, 196°C or higher, 198°C or higher, 200°C or higher Preferably, the temperature is 202°C or higher, 204°C or higher, 206°C or higher, 208°C or higher, 210°C or higher, 212°C or higher, 214°C or higher, 216°C or higher, or 218°C or higher, and may be 400°C or lower, 390°C or lower, 380°C or lower, 370°C or lower, 360°C or lower, 350°C or lower, 340°C or lower, 330°C or lower, 320°C or lower, 310°C or lower, or 300°C or lower.

[0078] The pour point of the lubricating oil composition of one embodiment of the present invention may be −30.0°C or less, −32.5°C or less, −35.0°C or less, −37.5°C or less, −40.0°C or less, −42.5°C or less, −45.0°C or less, −47.5°C or less, −50.0°C or less, −52.5°C or less, −55.0°C or less, −57.5°C or less, −60.0°C or less, or less than −60.0°C.

[0079] The thermal conductivity at 20°C of the lubricating oil composition of one embodiment of the present invention may be 0.130 W / (m·K) or more, 0.132 W / (m·K) or more, 0.134 W / (m·K) or more, 0.136 W / (m·K) or more, 0.138 W / (m·K) or more, 0.140 W / (m·K) or more, 0.142 W / (m·K) or more, 0.144 W / (m·K) or more, 0.146 W / (m·K) or more, or 0.148 W / (m·K) or more.

[0080] The thermal conductivity at 50°C of the lubricating oil composition of one embodiment of the present invention may be 0.120 W / (m·K) or more, 0.122 W / (m·K) or more, 0.124 W / (m·K) or more, 0.126 W / (m·K) or more, 0.128 W / (m·K) or more, 0.130 W / (m·K) or more, 0.132 W / (m·K) or more, 0.134 W / (m·K) or more, 0.136 W / (m·K) or more, 0.138 W / (m·K) or more, 0.140 W / (m·K) or more, 0.142 W / (m·K) or more, or 0.144 W / (m·K) or more.

[0081] The thermal conductivity at 100°C of the lubricating oil composition of one embodiment of the present invention may be 0.110 W / (m·K) or more, 0.112 W / (m·K) or more, 0.114 W / (m·K) or more, 0.116 W / (m·K) or more, 0.118 W / (m·K) or more, 0.120 W / (m·K) or more, 0.122 W / (m·K) or more, 0.124 W / (m·K) or more, 0.126 W / (m·K) or more, 0.128 W / (m·K) or more, 0.130 W / (m·K) or more, 0.132 W / (m·K) or more, 0.134 W / (m·K) or more, or 0.136 W / (m·K) or more.

[0082] The lubricating oil composition of one embodiment of the present invention may have a volume resistivity measured under conditions of 80°C and 250 V / mm of 1.0 TΩ·m or more, 5.0 TΩ·m or more, 10.0 TΩ·m or more, 15.0 TΩ·m or more, 20.0 TΩ·m or more, 25.0 TΩ·m or more, 30.0 TΩ·m or more, 40.0 TΩ·m or more, 50.0 TΩ·m or more, 60.0 TΩ·m or more, 70.0 TΩ·m or more, 80.0 TΩ·m or more, 90.0 TΩ·m or more, or 100.0 TΩ·m or more.

[0083] The thermal conductivity of the lubricating oil composition of one embodiment of the present invention is preferably 0.130 W / mK or more, 0.132 W / mK or more, 0.134 W / mK or more, 0.136 W / mK or more, 0.138 W / mK or more, 0.140 W / mK or more, or 0.142 W / mK or more, and may be 0.200 W / mK or less, 0.180 W / mK or less, or 0.160 W / mK or less.

[0084] [Uses of Lubricating Oil Composition] The lubricating oil base oil of one embodiment of the present invention is excellent in various properties such as viscosity characteristics, low-temperature fluidity, handleability, fuel economy, and cooling properties. Therefore, lubricating oil compositions containing this lubricating oil base oil also have the above-mentioned excellent properties and can be suitably used for cooling equipment installed in electric vehicles and lubricating drive mechanisms. In consideration of these properties, the lubricating oil composition of one embodiment of the present invention is suitable as a lubricating oil composition for cooling at least one equipment installed in an electric vehicle selected from a motor, a battery, an inverter, and an engine, and for lubricating a drive mechanism installed in the equipment or in a separate equipment.

[0085] Therefore, the present invention also provides the following aspects: [1] A method for cooling equipment mounted on an electric vehicle using the lubricating oil composition of one aspect of the present invention. [2] Equipment mounted on an electric vehicle filled with the lubricating oil composition of one aspect of the present invention as a cooling fluid.

[0086] Examples of the electric vehicles described in [1] and [2] above include hybrid vehicles and electric vehicles. Examples of equipment installed in the electric vehicles include at least one selected from a motor, a battery, an inverter, and an engine. The equipment may also be an equipment in which a motor and a reduction gear are integrated. When the lubricating oil composition of one embodiment of the present invention is used in an equipment in which a motor and a reduction gear are integrated, the lubricating oil composition can function as a cooling fluid for the motor and as a lubricating fluid for the reduction gear.

[0087] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples. The methods for measuring or calculating various properties are as follows.

[0088] (1) CH group and CH ２ Total integrated intensity ratio of groups (nonCH ３ ) Using an NMR device, the measurement sample was measured under the following measurement conditions. １ H-NMR spectrum was obtained. Measurement equipment: JNM-ECZ400R (product name, manufactured by JEOL Ltd.) Measurement sample: solution obtained by adding 1.0 mL of deuterated chloroform to 1.0 mL of lubricating base oil Measurement temperature: 20°C Resonance frequency: 400 MHz Number of accumulations: 8 Measurement time: about 1 minute Observation range: -2.5 to 12.5 ppm Sample rotation speed: 15 Hz １ Of the two peaks detected in the chemical shift range of 0.0 to 2.0 ppm in the H-NMR spectrum, the peak on the lower magnetic field side is identified as a CH group or a CH ２ The peak on the other high magnetic field side was identified as a peak derived from CH ３ The peaks were identified as those derived from the CH group. ３ The integral intensity S2 of the peak derived from the CH group or CH ２ The ratio [S1 / S2] of the integrated intensities S1 of the peaks originating from the CH group and the CH ２ Total integrated intensity ratio of groups (nonCH ３ )

[0089] (2) Average Carbon Number (Cav) A gas chromatogram of the measurement sample was obtained by gas chromatography mass spectrometry (GC / MS) under the following measurement conditions. (GC section) Measuring device: Agilent Technology 8890 series (product name, manufactured by Agilent Technologies, Inc.) Column: HP-5MS column (length: 30 mm, inner diameter: 0.25 mm, film thickness: 0.25 μm, manufactured by Agilent Technologies, Inc.) Carrier gas: Helium (114 kPa) Measurement sample: 0.1 g of sample diluted with 1.0 mL of hexane and measured Flow mode: Constant pressure Sample injection amount: 0.3 μL Split ratio: 10:1 Detector: Flame ionization detector (FID) Detector temperature: 350°C Injection port temperature: 300°C Oven temperature: After holding at 50°C for 1 minute, the temperature was increased to 320°C at a rate of 5°C / min and maintained for 10 minutes. (MS Unit) - Instrument Name: Agilent Technology 5977B Series (Product Name, manufactured by Agilent Technologies, Inc.) - Ion Source Temperature: 230°C - Transfer Line Temperature: 300°C - Scan Range: 35-550 - Ionization Voltage: 70 eV - Ionization Method: EI Method. Furthermore, under the above measurement conditions, gas chromatograms of standard samples with each carbon number were obtained using gas chromatography mass spectrometry (GC / MS), and data on the elution time (min) for each carbon number was previously obtained. Based on the obtained elution time data for each carbon number, the carbon numbers of the peaks in the gas chromatogram of the measurement sample were identified. The content ratio of each carbon number component in the measurement sample was then determined from the area ratio of the peak for each carbon number to the total area of ​​all peaks excluding the solvent in the gas chromatogram, and the weighted average of the carbon numbers was defined as the average carbon number (Cav) of the measurement sample.

[0090] (3) Average branch number (avB) Using an NMR device, the average branch number (avB) of the measurement sample was measured under the following measurement conditions. １３A C-NMR spectrum was obtained. Measurement equipment: JNM-ECZ400R (product name, manufactured by JEOL Ltd.) Measurement sample: 1.0 mL of lubricating base oil diluted with 1.0 mL of deuterated chloroform Measurement temperature: 20°C Resonance frequency: 400 MHz Number of accumulations: 2048 Measurement time: approximately 16 hours Observation range: -25 to 225 ppm Sample rotation speed: 15 Hz １３ The sum of the integrated intensities in the chemical shift range of 5.0 to 60.0 ppm in the C-NMR spectrum (a) and the terminal CH ３ The sum of integrated intensities (b) in the chemical shift ranges of 5.0 to 20.0 ppm and 22.45 to 22.80 ppm attributable to the α- and β-membered groups was calculated. Then, the ratio [(b) / (a)] of the sum of integrated intensities (b) to the sum of integrated intensities (a) was calculated, and the average number of branches (avB) was calculated from the value [(b) / (a)] and the value of the average number of carbon atoms (Cav) calculated in (2) above, based on the following formula (ii): Formula (ii): avB = Cav × [(b) / (a)] - 2

[0091] (4) Paraffin ratio The CH group and CH ２ Total integrated intensity ratio of groups (nonCH ３ The paraffin ratio was calculated from the value of [nonCH ], the value of the average carbon number (Cav) calculated in (2) above, and the value of the average branch number (avB) calculated in (3) above, based on the following formula (i): Formula (i): Paraffin ratio = [nonCH ３ ×3×(avB+2)+3×(avB+2)] / [2×Cav+2]

[0092] Example 1: CTL wax produced from coal (wax obtained by gasifying coal once and then using the Fischer-Tropsch process) was hydrotreated and then hydroisomerized using a platinum-supported silica aluminophosphate catalyst at a hydrogen partial pressure of 4 MPa, a reaction temperature of 300°C, and an LHSV of 1.0 hr. －１ The refined oil after the treatment was distilled under reduced pressure to obtain a crude oil having a kinematic viscosity of 2.0 mmHg at 100°C. ２ The fraction with a viscosity of about / s was collected to obtain lubricating base oil (1). Note that Figure 1 shows the viscosity of lubricating base oil (1) measured under the above conditions. １The H-NMR spectrum of lubricating base oil (1) measured under the above conditions is shown in FIG. １３ C-NMR spectrum.

[0093] Example 2: CTL wax produced from coal was hydrotreated and then hydroisomerized using a platinum-supported silica aluminophosphate catalyst at a hydrogen partial pressure of 4 MPa, a reaction temperature of 300°C, and an LHSV of 1.0 hr. －１ The refined oil after the treatment was distilled under reduced pressure to obtain a crude oil having a kinematic viscosity of 3.0 mmHg at 100°C. ２ The fraction having a viscosity of about / s was collected to obtain lubricating base oil (2).

[0094] Example 3: CTL wax produced from coal was hydrotreated and then hydroisomerized using a platinum-supported silica aluminophosphate catalyst under a hydrogen partial pressure of 4 MPa, a reaction temperature of 300°C, and an LHSV of 1.0 hr. －１ The refined oil after the treatment was distilled under reduced pressure to obtain a crude oil having a kinematic viscosity of 4.0 mmHg at 100°C. ２ The fraction with a viscosity of about / s was collected to obtain lubricating base oil (3).

[0095] Comparative Example 1 GTL wax (wax produced from natural gas by the Fischer-Tropsch process) was hydrotreated and then hydroisomerized using a platinum-supported zeolite catalyst at a hydrogen partial pressure of 8 MPa, a reaction temperature of 350°C, and an LHSV of 1.0 hr. －１ The refined oil after the treatment was distilled under reduced pressure to obtain a crude oil having a kinematic viscosity of 2.4 mmHg at 100°C. ２ The fraction having a viscosity of about / s was collected to obtain lubricating base oil (4).

[0096] Comparative Example 2 GTL wax was hydrotreated and then hydroisomerized using a platinum-supported zeolite catalyst under a hydrogen partial pressure of 8 MPa, a reaction temperature of 350°C, and an LHSV of 1.0 hr. －１ The refined oil after the treatment was distilled under reduced pressure to obtain a crude oil having a kinematic viscosity of 2.7 mmHg at 100°C. ２ The fraction having a viscosity of about / s was collected to obtain lubricating base oil (5).

[0097] Comparative Example 3: GTL wax was hydrotreated and then hydroisomerized using a platinum-supported zeolite catalyst under a hydrogen partial pressure of 8 MPa, a reaction temperature of 350°C, and an LHSV of 1.0 hr. －１ The refined oil after the treatment was distilled under reduced pressure to obtain a crude oil having a kinematic viscosity of 4.0 mmHg at 100°C. ２ The fraction having a viscosity of about / s was collected to obtain lubricating base oil (6).

[0098] Comparative Example 4: A bottom oil obtained by hydrocracking a vacuum gas oil was hydroisomerized using a platinum-supported zeolite catalyst under a hydrogen partial pressure of 4 MPa, a reaction temperature of 330°C, and an LHSV of 1.0 hr. －１ The refined oil after the treatment was distilled under reduced pressure to remove light fractions so that the flash point was 210°C or higher. Then, using a nickel-tungsten catalyst, the hydrogen partial pressure was 20 MPa, the reaction temperature was 270°C, and the LHSV was 0.5 hr. －１ The refined oil after the treatment was distilled under reduced pressure to obtain a crude oil having a kinematic viscosity of 2.3 mmHg at 100°C. ２ The fraction having a viscosity of about / s was collected to obtain lubricating base oil (7).

[0099] Comparative Example 5: Bottom oil obtained by hydrocracking vacuum gas oil was mixed with wax obtained by solvent dewaxing, and the mixture was subjected to hydroisomerization using a platinum-supported zeolite catalyst at a hydrogen partial pressure of 4 MPa, a reaction temperature of 330°C, and an LHSV of 1.0 hr. －１ The refined oil after the treatment was distilled under reduced pressure to remove light fractions so that the flash point was 210°C or higher. Then, using a nickel-tungsten catalyst, the hydrogen partial pressure was 20 MPa, the reaction temperature was 270°C, and the LHSV was 0.5 hr. －１ The refined oil after the treatment was distilled under reduced pressure to obtain a crude oil having a kinematic viscosity of 2.7 mmHg at 100°C. ２ The fraction having a viscosity of about / s was collected to obtain lubricating base oil (8).

[0100] Comparative Example 6: A bottom oil obtained by hydrocracking a vacuum gas oil was hydroisomerized using a platinum-supported zeolite catalyst under a hydrogen partial pressure of 4 MPa, a reaction temperature of 330°C, and an LHSV of 1.0 hr.－１ The refined oil after the treatment was subjected to hydroisomerization and dewaxing treatment under the conditions of: After removing light components by vacuum distillation so that the flash point was 200 to 210°C, the oil was subjected to hydroisomerization and dewaxing treatment under the conditions of: a hydrogen partial pressure of 20 MPa, a reaction temperature of 290°C, and LHSV of 0.5 hr using a nickel-tungsten catalyst. －１ The refined oil after the treatment was distilled under reduced pressure to obtain a crude oil having a kinematic viscosity of 4.2 mmHg at 100°C. ２ The fraction having a viscosity of about / s was collected to obtain lubricating base oil (9).

[0101] The properties of the produced lubricating base oils (1) to (9) were measured by the following methods. The results are shown in Table 1.

[0102] [40°C, 100°C kinematic viscosity, viscosity index] Measured and calculated in accordance with JIS K2283:2000. [15°C density] Measured at 15°C in accordance with JIS K2249. [Pour point] Measured in accordance with JIS K2269:1987 (Test method for pour point and cloud point of crude oil and petroleum products). [Flash point] Measured by the Pensky-Martens closed-cell method (PM method) in accordance with JIS K2265-3:2007. [Traction coefficient] Measurement was performed using a traction coefficient measuring device (product name: MTM2 (Mini Traction Machine 2, manufactured by PCS Instruments). Specifically, the lubricating base oil to be measured was heated, and the traction coefficient was measured at an oil temperature of 40°C, a load of 70N, an average rolling speed of 2000mm / s, and a slide-to-roll ratio (SRR) of 50%. [Thermal conductivity] Thermal conductivity was measured at temperatures of 20°C, 50°C, and 100°C using a thermal conductivity measuring device (TCi, manufactured by C-THERM Technology) in accordance with ASTM D7896-19.

[0103]

[0104] From Table 1, the lubricating base oils (1) to (3) of Examples 1 to 3 are judged to have good viscosity characteristics, low-temperature fluidity, handleability, fuel economy, and cooling properties based on the values ​​of 40 ° C. kinematic viscosity, pour point, flash point, traction coefficient, and thermal conductivity. On the other hand, the lubricating base oils (4) to (9) of Comparative Examples 1 to 6 are considered to have high traction coefficients and poor fuel economy performance. Furthermore, the lubricating base oils (8) to (9) of Comparative Examples 5 and 6 are judged to have high pour points and poor low-temperature fluidity.

Claims

1. A lubricating base oil used for cooling equipment and lubricating drive mechanisms mounted on electric vehicles, which satisfies the following requirements (I) and (II): Requirement (I): The paraffin ratio calculated by the following formula (i) is 0.880 or more. Formula (i): Paraffin ratio = [nonCH ３ × 3 × (avB+2) + 3 × (avB+2)] / [2 × Cav+2] In the formula (i), ３ was measured using an NMR device １ In the H-NMR spectrum, ３ The integral intensity S2 of the peak derived from the CH group or CH ２ The ratio [S1 / S2] of the integrated intensity S1 of the peak derived from the CH group and the CH ２ Cav is the average carbon number measured by gas chromatography mass spectrometry (GC / MS). avB indicates the average branch number, measured using an NMR device. １３ The total integrated intensity (a) of the terminal CH ３ It is a value calculated based on the following formula (ii) from the ratio [(b) / (a)] of the total integrated intensity (b) of the chemical shifts attributable to the group in the ranges of 5.0 to 20.0 ppm and 22.45 to 22.80 ppm: Formula (ii): avB=Cav×[(b) / (a)]-2 Requirement (II): The ratio [avB / Cav] of the average number of branches (avB) to the average number of carbon atoms (Cav) is 0.110 or less.

2. The lubricating base oil according to claim 1, further satisfying the following requirement (III): Requirement (III): the average carbon number (Cav) is 19.1 or more.

3. The lubricating base oil according to claim 1 or 2, further satisfying the following requirement (IV): Requirement (IV): The CH groups and CH ２ Total integrated intensity ratio of groups (nonCH ３ ) is 2.00 or more.

4. The lubricating base oil according to any one of claims 1 to 3, wherein the average number of branches (avB) is 1.80 or greater and 3.00 or less.

5. The lubricating base oil according to any one of claims 1 to 4, wherein the ratio [avB / Cav] is 0.080 or greater and 0.110 or less.

6. The lubricating base oil according to any one of claims 1 to 5, wherein the lubricating base oil is a base oil obtained by refining a feedstock containing CTL oil produced from coal.

7. The lubricating base oil of claim 6, wherein the refining process includes at least hydroisomerization.

8. A lubricating base oil made from refined CTL oil produced from coal, used to cool equipment installed in electric vehicles.

9. The kinematic viscosity of the lubricating base oil at 100°C is 1.80 mm ２ / s or more 4.30mm ２ The lubricating base oil according to any one of claims 1 to 8, wherein the viscosity is 1 / 2 or less.

10. The kinematic viscosity of the lubricating base oil at 40°C is 5.0 mm ２ / s or more 25.0mm ２ The lubricating base oil according to any one of claims 1 to 9, wherein the viscosity is 1 / 2 or less.

11. The density of the lubricating base oil at 15°C is 0.750 g / cm ３ The lubricating base oil according to any one of claims 1 to 10.

12. The lubricating base oil according to any one of claims 1 to 11, wherein the lubricating base oil has a flash point of 160°C or higher.

13. The lubricating base oil according to any one of claims 1 to 12, wherein the lubricating base oil has a pour point of -30.0°C or lower.

14. The lubricating base oil according to any one of claims 1 to 13, wherein the lubricating base oil has a traction coefficient of 0.0470 or less, measured under the conditions of an oil temperature of 40°C, a load of 70 N, an average rolling speed of 2000 mm / s, and a slide-to-roll ratio of 50%.

15. The lubricating base oil according to any one of claims 1 to 14, wherein the thermal conductivity of the lubricating base oil at 20°C is 0.130 W / (m·K) or more.

16. A lubricating oil composition used for cooling equipment and lubricating drive mechanisms mounted on electric vehicles, comprising the lubricating base oil according to any one of claims 1 to 15.

17. The lubricating oil composition of claim 16, further comprising one or more lubricating oil additives selected from pour point depressants, viscosity index improvers, antioxidants, extreme pressure agents, metal detergents, ashless dispersants, metal deactivators, corrosion inhibitors, rust inhibitors, and antifoaming agents.

18. The lubricating oil composition according to claim 17, wherein the total content of the lubricating oil additives is 5.0 mass % or less based on the total amount of the lubricating oil composition.

19. A method for cooling equipment mounted on an electric vehicle, comprising using the lubricating oil composition according to any one of claims 16 to 18.

20. The method for cooling equipment according to claim 19, wherein the equipment is at least one selected from the group consisting of a motor, a battery, an inverter, and an engine.

21. The method for cooling equipment according to claim 19, wherein the equipment is an equipment in which a motor and a reducer are integrated.

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