JP2022158116A - Lubricant composition - Google Patents

Abstract

To provide a lubricant composition that contains an oil-based friction modifier, having improved friction reducing performance in the lubrication of a gear.SOLUTION: A lubricant composition contains: (A) a lubricant base oil that contains one or more mineral base oils, one or more synthetic base oils, or a combination thereof, while having a kinematic viscosity at 40°C of 40 mm2/s or less; and (B) a partial ester of (b1) one or more saturated or unsaturated monovalent fatty acids having 3 to 30 carbon atoms and (b2) one or more glycerol oligomers having a polymerization degree of 3 to 6 in an amount of 0.05-2.5 mass% based on the total amount of the composition.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a lubricating oil composition, and more particularly to a lubricating oil composition suitable for gear lubrication.

Lubricating oil is used in internal combustion engines, automatic transmissions, bearings, and the like to facilitate their operation. In general, lubricating oils are blended with various additives in order to provide the performance required for the lubricating oils.

Among lubricating oil additives, additives that have the effect of reducing frictional resistance (friction modifiers, hereinafter sometimes referred to as "FM") are important components in reducing energy loss due to friction. Commonly used FMs can be classified into organic molybdenum-based FMs containing molybdenum and oily agent-based FMs (also referred to as ashless FMs) that reduce friction by improving oiliness.

MoDTC (molybdenum dithiocarbamate) and MoDTP (molybdenum dithiophosphate) are widely known as organic molybdenum FMs (see, for example, Patent Document 1). Although these organic molybdenum-based FMs are excellent in the friction-reducing effect at the initial stage of use, there is a limit to maintaining the friction-reducing effect satisfactorily over a long period of time. Also, organic molybdenum-based FMs contain ash, making it difficult to reuse used lubricating oil. Therefore, it is required to reduce the amount of organic molybdenum FM added.

On the other hand, oily agent-based FMs have the potential to overcome the above-mentioned problems of organic molybdenum-based FMs, so the importance of oily agent-based FMs is increasing (see Patent Documents 2 and 3, for example).

JP 2013-133453 A JP 2009-235252 A JP 2006-257383 A Japanese Patent Publication No. 2016-540870 JP 2015-521685 A JP 2011-140643 A WO2003/031543 JP-A-11-217577 Japanese Patent Application Laid-Open No. 2005-061610

However, the conventional oil-based FM still has room for improvement in terms of gear friction coefficient. One example of means for improving the energy efficiency of mechanical devices is the use of a low-viscosity lubricating oil using a low-viscosity base oil. Low-viscosity lubricating oil can reduce stirring resistance and improve energy efficiency. However, when using a low-viscosity base oil, the oil film thickness tends to decrease, so the transition from the hydrodynamic lubrication region to the mixed lubrication region occurs with a lower load than conventional lubricating oils using higher-viscosity base oils. begins and the coefficient of friction begins to increase. This problem is particularly acute in the lubrication of gears where the load on the lubricated surfaces increases in proportion to the driving force being transmitted.

An object of the present invention is to provide a lubricating oil composition containing an oil-based friction modifier with improved friction-reducing performance in lubricating gears even though it has a low viscosity.

The present invention includes the following embodiments [1] to [6].

[1] (A) a lubricating base oil comprising one or more mineral base oils, one or more synthetic base oils, or a combination thereof, and having a kinematic viscosity at 40°C of 40 mm ² /s or less; ,
(B) a partial ester of one or more saturated or unsaturated monovalent fatty acids (b1) having 3 to 30 carbon atoms and one or more glycerin oligomers (b2) having a degree of polymerization of 3 to 6; A lubricating oil composition characterized in that it contains 0.05 to 2.5% by mass on a basis.

[2] The lubricating oil composition according to [1], wherein the fatty acid (b1) has 6 to 30 carbon atoms.

[3] (B′) contains or does not contain a partial ester of glycerin, a glycerin polymer other than the glycerin oligomer (b2), or a combination thereof with a fatty acid;
[1] or [ 2].

[4] further comprising one or more additives selected from metallic detergents, ashless dispersants, phosphorus-containing antiwear agents, sulfur-containing extreme pressure agents, antioxidants, and viscosity index improvers, [1]- [3] The lubricating oil composition according to any one of [3].

[5] The lubricating oil composition according to any one of [1] to [4], which has a kinematic viscosity of 7.0 to 50 mm ² /s at 40°C.

[6] The lubricating oil composition according to any one of [1] to [5], which is used for gear lubrication.

The lubricating oil composition of the present invention is a lubricating oil composition containing a specific oil-based friction modifier, and can exhibit an improved friction-reducing effect in gear lubrication while having a low viscosity.

The present invention will be described in detail below. In this specification, unless otherwise specified, the notation "A to B" for numerical values A and B is equivalent to "A or more and B or less". If a unit is attached only to the numerical value B in such notation, the unit is applied to the numerical value A as well. As used herein, the terms "or" and "or" shall mean a logical sum unless otherwise specified. As used herein, the notation “E ₁ and/or E ₂ ” for elements E ₁ and E ₂ is equivalent to “E ₁ or E ₂ , or a combination thereof” and N elements E ₁ , . _{, E i , . _ _} , or a combination thereof” (i is a variable whose value is all integers satisfying 1<i<N). In this specification, magnesium is also included in the "alkaline earth metal".

In this specification, unless otherwise specified, the content of each element of calcium, magnesium, zinc, phosphorus, sulfur, boron, barium, and molybdenum in oil is determined by inductively coupled plasma emission spectroscopy in accordance with JIS K0116. It shall be measured by an analytical method (intensity ratio method (internal standard method)). Also, the nitrogen element content in the oil shall be measured by a chemiluminescence method in accordance with JIS K2609. The term "weight average molecular weight" as used herein means the weight average molecular weight in terms of standard polystyrene measured by gel permeation chromatography (GPC). GPC measurement conditions are as follows.
[GPC measurement conditions]
Apparatus: ACQUITY (registered trademark) APC UV RI system manufactured by Waters Corporation Column: ACQUITY (registered trademark) APC XT900A manufactured by Waters Corporation (gel particle size: 2.5 µm, column size (inner diameter x length): 4.6 mm, in order from the upstream side) × 150 mm) and one ACQUITY (registered trademark) APC XT200A manufactured by Waters Corporation (gel particle size 2.5 μm, column size (inner diameter × length) 4.6 mm × 150 mm) are connected in series Column temperature: 40 ℃
Sample solution: Tetrahydrofuran solution with a sample concentration of 1.0% by mass Eluent: Tetrahydrofuran solution Injection volume: 20.0 μL
Detection device: Differential refractive index detector Reference material: Standard polystyrene (Agilent EasiCal (registered trademark) PS-1 manufactured by Agilent Technologies) 8 points (molecular weight: 2698000, 597500, 290300, 133500, 70500, 30230, 9590, 2970)
If the weight-average molecular weight measured under the above conditions is less than 10,000, the column and reference substance are changed to the following conditions and re-measured.
Column: From the upstream side, one ACQUITY (registered trademark) APC XT125A manufactured by Waters Corporation (gel particle size 2.5 μm, column size (inner diameter x length) 4.6 mm x 150 mm), and ACQUITY manufactured by Waters Corporation (registered Trademark) APC XT45A (gel particle size 1.7 μm, column size (inner diameter x length) 4.6 mm x 150 mm) connected in series Reference material: standard polystyrene (Agilent EasiCal (registered trademark) PS- 1) 10 points (molecular weight: 30230, 9590, 2970, 890, 786, 682, 578, 474, 370, 266)

<(A) Lubricating base oil>
The lubricating oil composition of the present invention (hereinafter sometimes referred to as "lubricating oil composition" or "composition") comprises a major amount of lubricating base oil and one or more additives other than base oil. comprising In the lubricating oil composition of the present invention, the lubricating base oil comprises one or more mineral base oils, one or more synthetic base oils, or a combination thereof, and has a kinematic viscosity of 40 mm ² at 40 ° C. /s or less (hereinafter sometimes referred to as "(A) component") is used.

As the lubricating base oil, one or more mineral base oils, one or more synthetic base oils, or a mixture thereof can be used. In one embodiment, the lubricating base oil includes Group I base oil of API base oil classification (hereinafter sometimes referred to as "API Group I base oil"), Group II base oil (hereinafter referred to as "API Group II Group III base oil (hereinafter sometimes referred to as "API Group III base oil"), Group IV base oil (hereinafter sometimes referred to as "API Group IV base oil"). ), or Group V base oils (hereinafter sometimes referred to as "API Group V base oils"), or mixtures thereof. API Group I base oils are mineral base oils with a sulfur content of greater than 0.03 mass % and/or a saturate content of less than 90 mass % and a viscosity index of 80 or more and less than 120. API Group II base oils are mineral base oils having a sulfur content of 0.03 mass % or less, a saturate content of 90 mass % or more, and a viscosity index of 80 or more and less than 120. API Group III base oils are mineral base oils having a sulfur content of 0.03 wt.% or less, a saturates content of 90 wt.% or more, and a viscosity index of 120 or more. API Group IV base oils are poly-alpha-olefin base oils. API Group V base oils are base oils other than the above Groups I to IV, and preferred examples thereof include ester base oils.

In one embodiment, component (A) includes 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 combinations thereof can be preferably used.

Examples of mineral base oils include lubricating oil fractions obtained by atmospheric distillation and/or vacuum distillation of crude oil, which are subjected to solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrogen Examples include paraffinic base oils refined by one or a combination of two or more selected from refining treatments such as refining, sulfuric acid washing, clay treatment, normal paraffinic base oils, isoparaffinic base oils, and mixtures thereof. be able to. API Group II base oils and Group III base oils are typically produced via a hydrocracking process.

The %C _P of the mineral base oil is preferably 60 or more, more preferably 65 or more from the viewpoint of further improving the viscosity-temperature characteristics and fuel economy of the composition, and is also preferable from the viewpoint of increasing the solubility of additives. is 99 or less, more preferably 95 or less, even more preferably 94 or less, and in one embodiment can be 60-99, or 60-95, or 65-95, or 65-94.

The % CA of the mineral base oil is preferably 2 or less, more preferably 1 or less, still more preferably 0.8 or less, particularly preferably 0.8 or less, from the viewpoint of further improving the viscosity _- temperature characteristics and fuel economy of the composition. 5 or less.

The % CN of the mineral base oil is preferably 1 or more, more preferably 4 or more from the viewpoint of increasing the solubility of additives, and is also preferable from the viewpoint of further improving the viscosity _- temperature characteristics and fuel economy of the composition. is 40 or less, more preferably 35 or less, and can be 1-40, or 4-35 in one embodiment.

As used herein, %C _P , %C _N and %C _A are the percentages of the number of paraffin carbon atoms to the total number of carbon atoms, each determined by a method (ndM ring analysis) according to ASTM D 3238-85. , the percentage of the number of naphthenic carbons to the total number of carbons, and the percentage of the number of aromatic carbons to the total number of carbons. In other words, the preferred ranges of %C _P , %C _N and %C _A described above are based on the values determined by the above method. The % _CN given may show values greater than zero.

From the viewpoint of improving the viscosity-temperature characteristics of the composition, the content of saturated components in the mineral base oil is preferably 90% by mass or more, more preferably 95% by mass or more, and still more preferably 99%, based on the total amount of the base oil. % by mass or more. The term "saturated content" as used herein means a value measured according to ASTM D 2007-93.

The content of aromatics in the mineral base oil is preferably 0 to 10% by mass, more preferably 0 to 5% by mass, particularly preferably 0 to 1% by mass, based on the total amount of the base oil. In embodiments, it may be 0.1% by mass or more. By keeping the content of aromatics below the above upper limit, it is possible to improve low-temperature viscosity characteristics and viscosity-temperature characteristics in the new oil state, as well as further improve fuel efficiency. , it is possible to reduce the consumption of lubricating oil by reducing the evaporation loss of the lubricating oil. Moreover, when an additive is blended in the lubricating base oil, it becomes possible to effectively exhibit the effect of the additive. The lubricating base oil may not contain aromatics, but if the content of aromatics is equal to or higher than the above lower limit, the solubility of additives can be enhanced.

The term "aromatic content" as used herein means a value measured according to ASTM D 2007-93. Aromatic components generally include alkylbenzene, alkylnaphthalene, anthracene, phenanthrene and alkylated products thereof, compounds in which four or more benzene rings are condensed, pyridines, quinolines, phenols, naphthols and the like. Aromatic compounds with heteroatoms and the like are included.

Examples of API Group IV base oils include 2 to 32 carbon atoms, preferably 6 carbon atoms, such as ethylene-propylene copolymers, polybutene, 1-octene oligomers, 1-decene oligomers, and hydrogenated products thereof. Oligomers and co-oligomers of .about.16 α-olefins and their hydrogenation products may be mentioned.

Preferred examples of API Group V base oils include monoesters (eg butyl stearate, octyl laurate, 2-ethylhexyl oleate, etc.); diesters (eg ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, di-2-ethylhexyl sebacate, etc.); polyesters (eg, trimellitate esters, etc.); polyol esters (eg, trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate, pentaerythritol) pelargonate, etc.) can be mentioned. Other examples of API Group V base oils include aromatic synthetic base oils such as alkylbenzenes, alkylnaphthalenes, polyoxyalkylene glycols, dialkyldiphenyl ethers, polyphenyl ethers, and the like.

The kinematic viscosity of the lubricating base oil (all base oils) at 40° C. is 40 mm ² /s or less, preferably 30 mm ² /s or less, more preferably 20 mm, from the viewpoint of improving energy saving and low-temperature viscosity characteristics of the lubricating oil composition. ² /s or less, and preferably 6.0 mm ² /s or more, more preferably 6.5 mm ² /s or more, still more preferably 7.0 mm ² /s or more from the viewpoint of enhancing wear resistance and seizure resistance. and in one embodiment can be 6.0-40 mm ² /s, or 6.5-30 mm ² /s, or 7.0-20 mm ² /s. In this specification, "kinematic viscosity at 40 ° C." is based on JIS K 2283-2000 and measured using an automatic viscometer (trade name "CAV-2100", manufactured by Cannon Instrument) as a measuring device. Means kinematic viscosity at 40°C.

The kinematic viscosity at 100° C. of the lubricating base oil (all base oils) is preferably 5.0 mm ² /s or less, more preferably 4.0 mm ² from the viewpoint of further enhancing the low-temperature viscosity characteristics of the lubricating oil composition and energy saving. /s or less, more preferably 3.5 mm ² /s or less, and from the viewpoint of enhancing wear resistance and seizure resistance, preferably 1.9 mm ² /s or more, more preferably 2.0 mm ² /s or more, It is more preferably 2.1 mm ² /s or more, and in one embodiment, 1.9 to 5.0 mm ² /s, or 2.0 to 4.0 mm ² /s, or 2.1 to 3.5 mm ² /s. In this specification, "kinematic viscosity at 100 ° C." is based on JIS K 2283-2000 and is measured using an automatic viscometer (trade name "CAV-2100", manufactured by Cannon Instrument) as a measuring device. Means kinematic viscosity at 100°C.

The viscosity index of the lubricating base oil (whole base oil) is preferably 100 or more, more preferably 105 or more, from the viewpoint of improving the viscosity-temperature characteristics of the composition and further improving fuel economy and wear resistance, More preferably 110 or more, particularly preferably 115 or more, most preferably 120 or more. In this specification, the viscosity index is a viscosity index measured using an automatic viscometer (trade name “CAV-2100”, manufactured by Cannon Instruments) as a measuring device in accordance with JIS K 2283-2000. means.

The pour point of the lubricating base oil (whole base oil) is preferably −10° C. or less, more preferably −12.5° C. or less, still more preferably −15° C. or less from the viewpoint of the low-temperature fluidity of the entire lubricating oil composition. , particularly preferably -17.5°C or lower, most preferably -20.0°C or lower. As used herein, the term "pour point" means the pour point measured according to JIS K 2269-1987.

The sulfur content in the base oil depends on the sulfur content of the feedstock. For example, when a raw material containing substantially no sulfur such as a synthetic wax component obtained by a Fischer-Tropsch reaction or the like is used, a base oil containing substantially no sulfur can be obtained. In addition, when using raw materials containing sulfur such as slack wax obtained in the refining process of base oil and microwax obtained in the waxing process, the sulfur content in the obtained base oil is usually 100 mass ppm or more. The sulfur content in the lubricating base oil (whole base oil) is usually 0.03% by mass or less, preferably 0.01% by mass or less from the viewpoint of oxidation stability. As used herein, the sulfur content in the base oil means the sulfur content measured according to JIS K 2541-2003.

The lubricating base oil may consist of a single base oil component, as long as the kinematic viscosity at 40 ° C. is 40 mm ² / s or less as the entire base oil (whole base oil). It's okay.

In one embodiment, the lubricating base oil is 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. Base oil, or combinations thereof, may comprise 80 to 100 wt.%, or 90 to 100 wt.%, or 90 to 99 wt.%, or 95 to 99 wt.% based on total base oil. The lubricating base oil may or may not contain an API Group V base oil, but the content of one or more API Group V base oils in the lubricating base oil is in one embodiment From the viewpoint of enhancing oxidation stability, it is preferably 0 to 50% by mass, or 0 to 45% by mass, based on the total amount of base oil, and from the viewpoint of enhancing fatigue resistance, it may be 1 to 50% by mass, or 1 to 45% by mass. . The lubricant base oil may or may not contain an API Group IV base oil, but in one embodiment the content of one or more API Group IV base oils in the lubricant base oil is , 0 to 70% by mass, or 0 to 65% by mass, or 1 to 70% by mass, or 1 to 65% by mass based on the total amount of base oil.

The content of the lubricating base oil (total base oil) in the lubricating oil composition is 60 mass% or more based on the total amount of the lubricating oil composition, preferably 60 to 98.5 mass%, more preferably 70 to 98 .5% by weight, and in one embodiment from 75 to 97% by weight.

<(B) Fatty acid ester of glycerin oligomer>
The lubricating oil composition of the present invention comprises one or more saturated or unsaturated monovalent fatty acids having 3 to 30 carbon atoms (hereinafter sometimes referred to as "fatty acid (b1)") and a degree of polymerization of 3 to 6. A partial ester (hereinafter sometimes referred to as "(B) component") with one or more glycerin oligomers (hereinafter sometimes referred to as "glycerin oligomer (b2)") is added in an amount of 0.5% based on the total amount of the composition. 05 to 2.5% by mass. As used herein, the ester of glycerin oligomer (b2) and fatty acid (b1) being a "partial ester" means that the ester compound has one or more free hydroxy groups. That is, in the component (B), at least one hydroxy group of the glycerin oligomer (b2) remains unesterified.

The fatty acid (b1) may be one kind of fatty acid or a combination of two or more kinds of fatty acids. The fatty acid (b1) may be a saturated fatty acid or an unsaturated fatty acid. The fatty acid (b1) may be a straight chain fatty acid or a branched chain fatty acid, but is preferably a straight chain fatty acid. Examples of fatty acids (b1) include propionic acid, butanoic acid, pentanoic acid, hexanoic 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, nonadecanic acid, eicosanoic acid, heneicosanoic acid, docosanoic acid, tricosanoic acid, saturated fatty acids such as tetracosanoic acid; Unsaturated fatty acids such as 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, tricosenoic acid, tetracosenoic acid; and mixtures thereof.

The number of carbon atoms in the fatty acid (b1) is 3 or more, preferably 6 or more, and in one embodiment, 8 or more from the viewpoint of enhancing the friction reduction effect in gear lubrication. In one embodiment it is 18 or less, and in one embodiment it can be 3-30, or 6-30, or 8-30, or 8-24, or 8-18. Preferred examples of fatty acids (b1) include caprylic acid, 2-ethylhexanoic acid, pelargonic acid, capric acid, lauric acid, myristic acid, myristoleic acid, palmitic acid, palmitoleic acid, vaccenic acid, stearic acid, oleic acid, Elaidic acid, linoleic acid, linolenic acid, eleostearic acid, stearidonic acid, arachidic acid, gadoleic acid, eicosenoic acid, eicosapentaenoic acid, behenic acid, erucic acid, sardine acid, docosahexaenoic acid, lignoceric acid, nisinic acid, and these and the like. As a mixture containing two or more kinds of fatty acids, fatty acids derived from natural fats and oils or hydrogenated natural fats and oils may be used. Examples of fatty acids derived from natural fats and oils include coconut oil fatty acid, palm kernel oil fatty acid, palm oil fatty acid, paulownia oil fatty acid, tall oil fatty acid, corn oil fatty acid, rapeseed oil fatty acid, olive oil fatty acid, sesame oil fatty acid, soybean oil fatty acid, and rice bran. Oil fatty acids, sunflower oil fatty acids, castor oil fatty acids, linseed oil fatty acids, fish oil fatty acids, beef tallow fatty acids, hydrogenated products thereof, and mixtures thereof. Fatty acids derived from these natural fats and oils are mixtures of two or more fatty acids having 8 to 24 carbon atoms.

The glycerin oligomer (b2) can be produced, for example, by dehydration condensation of glycerin or ring-opening polymerization of glycidol. The glycerin oligomer (b2) may be an oligomer having a single degree of polymerization, or a combination of two or more oligomers having different degrees of polymerization. The degree of polymerization of the glycerin oligomer (b2) is 3 or more from the viewpoint of enhancing the gear friction reduction effect, and 6 or less, preferably 5 or less from the same viewpoint, and 4 or less in one embodiment. can be 3-6, or 3-5, or 3-4.

Component (B) is an ester of fatty acid (b1) and glycerol oligomer (b2). In one embodiment, component (B) can be produced by a dehydration condensation reaction between fatty acid (b1) and glycerin oligomer (b2). Such a dehydration condensation reaction is performed, for example, by reacting a fatty acid (b1) and a glycerin oligomer (b2) in an organic solvent (e.g. toluene etc.) forming an azeotropic mixture with water in an acid catalyst (e.g. sulfuric acid, trifluoroacetic acid). etc.), while heating under reflux, azeotropically removing water produced as the condensation reaction proceeds. In another embodiment, component (B) can be produced by reacting fatty acid (b1), glycerin oligomer (b2), and a condensing agent in a solvent. Condensing agents include carbodiimide condensing agents such as N,N'-dicyclohexylcarbodiimide (DCC), N,N'-diisopropylcarbodiimide (DIC), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC). imidazole condensing agents such as N,N'-carbonyldiimidazole (CDI) and 1,1'-carbonyldi(1,2,4-triazole) (CDT); 4-(4,6-dimethoxy-1, 3,5-triazin-2-yl)-4-methylmorpholinium chloride hydrate (DMT-MM) and other triazine condensing agents; 2-chloro-1-methylpyridinium p-toluenesulfonate, 2-fluoro- 2-halopyridinium salts such as 1-methylpyridinium p-toluenesulfonate; 2,4,6-trichlorobenzoyl chloride (TCBC); 2-methyl-6-nitrobenzoic anhydride (MNBA); diethyl azodicarboxylate (DEAD ) with triphenylphosphine; phosphines such as chlorodiphenylphosphine and 2,2′-dipyridyl disulfide; 2,6-dimethyl-1,4-benzoquinone (DMBQ), tetrafluoro-1,4-benzoquinone A known condensing agent that can be used for esterification, such as combination with p-benzoquinones such as dimesitylammonium pentafluorobenzenesulfonate, can be used without particular limitation. The condensing agent is used together with a catalyst such as 4-dimethylaminopyridine (DMAP), N-hydroxysuccinimide (NHS), 1-hydroxybenzotriazole (HOBt), 1-hydroxy-7-azabenzotriazole (HOAt). good too. In another embodiment, component (B) can be produced by reacting an acylating agent derived from fatty acid (b1) with glycerol oligomer (b2) in a solvent. Examples of acylating agents derived from fatty acid (b1) include acid halides of fatty acid (b1) (e.g., acid chlorides, acid bromides, etc.), active esters of fatty acid (b1) (e.g., fatty acid (b1) and N - esters with hydroxysuccinimide (NHS), esters with fatty acid (b1) and 1-hydroxybenzotriazole (HOBt), esters with fatty acid (b1) and 1-hydroxy-7-azabenzotriazole (HOAt), etc. ), acid anhydrides of fatty acids (b1), and the like. Acylating agents derived from fatty acids (b1) may be used with catalysts such as 4-dimethylaminopyridine (DMAP). Examples of the solvent include organic solvents that do not interfere with the condensation reaction (e.g., aliphatic hydrocarbon solvents such as hexane and petroleum ether; aromatic hydrocarbon solvents such as benzene, toluene, and xylene; dichloromethane, 1,2-dichloroethane, chlorobenzene, o - Halogenated hydrocarbon solvents such as dichlorobenzene, pyridine, etc.) can be used without particular limitation. In addition, in the condensation reaction for producing the component (B), if necessary, for the purpose of promoting the reaction, or an acid generated as the reaction progresses (for example, in a reaction using an acid halide, a halogen For the purpose of capturing hydrogen chloride, a suitable base (for example, amines such as triethylamine, pyridine, 2,6-lutidine, etc., organic lithium reagents such as butyllithium, inorganic bases such as potassium carbonate, etc.) are added to the reaction mixture. ) may be added.

The glycerin oligomer (b2) has a plurality of hydroxy groups capable of reacting with the fatty acid (b1) (or the acylating agent derived from the fatty acid (b1)). In the production of the component (B), the reaction molar ratio ((b2)/(b1)) between the fatty acid (b1) (or the acylating agent derived from the fatty acid (b1)) and the glycerin oligomer (b2) is, for example, 1 .0 to 10, preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and in one embodiment 1.0 to 2.0.

The component (B) has at least one free hydroxy group (hereinafter sometimes referred to as "residual hydroxy group") derived from the glycerin oligomer (b2). Since the glycerin oligomer (b2) with a degree of polymerization of p (p is an integer of 2 or more) has a maximum of p+2 hydroxy groups, when the component (B) has q (q is an integer of 1 or more) ester bonds, Component (B) has a maximum of p+2-q residual hydroxy groups. Here, the glycerin oligomer (b2) having a degree of polymerization of p has “maximum” p+2 hydroxy groups means that the glycerin oligomer (b2) can form a cyclic ether structure through a cyclization reaction accompanied by intramolecular dehydration. It reflects. Glycerin oligomer (b2) having r cyclic ether structures (where r is an integer of 0 or more, and r = 0 means not having a cyclic ether structure) is obtained by desorption of water accompanying cyclization. has lost 2r hydroxy groups. That is, a glycerin oligomer (b2) having a degree of polymerization of p and having r cyclic ether structures has p+2-2r hydroxy groups. However, under normal conditions, the cyclic ether structure formed by such a cyclization reaction is a six-membered ring structure, so the pair of two hydroxy groups involved in the intramolecular dehydration reaction is a glycerin oligomer (b2 ) are pairs of two hydroxy groups belonging to adjacent glycerol repeat units. Since each glycerin repeating unit other than the terminal end of the glycerin oligomer has one or less hydroxy groups, usually 0≦2r≦p, and therefore p+2−2r≧2. Since 2r is an even number, 0.ltoreq.2r.ltoreq.p when p is an even number, and 0.ltoreq.2r.ltoreq.p-1 when p is an odd number. Therefore, p+2-2r≧2 when p is an even number, and p+2-2r≧3 when p is an odd number. Such an intramolecular cyclization reaction can proceed not only during the production of the glycerin oligomer (b2) but also during the condensation reaction between the glycerin oligomer (b2) and the fatty acid (b1). The condensation reaction product of the glycerin oligomer (b2) and the fatty acid (b1) has s cyclic ether structures (where s is an integer of 0 or more, and s = 0 means that it does not have a cyclic ether structure. .), the condensation reaction product has p+2-q-2s residual hydroxy groups. Similarly, usually 0≤2s≤p (i.e., 0≤2s≤p when p is even, and 0≤2s≤p-1 when p is odd), so that p+2-q- when p is even. 2s≧2−q, and p+2−q−2s≧3−q when p is an odd number. That is, even if one or more cyclic ether structures are formed by the intramolecular dehydration reaction, one or more monoesters of the glycerin oligomer (b2) and the fatty acid (b1) (when the degree of polymerization of the glycerin oligomer (b2) is odd) has two or more free hydroxy groups.

After completion of the condensation reaction between the fatty acid (b1) and the glycerin oligomer (b2), unreacted raw materials can be removed by known methods such as washing with water, silica gel short pass column chromatography, and celite filtration. The resulting product comprises one or more partial esters having one or more free hydroxy groups (which may have one or more cyclic ether structures) and one or more partial esters having no free hydroxy groups. (which may have one or more cyclic ether structures). By further purifying the obtained product by known purification means such as column chromatography, the complete ester in the product may be removed or reduced and the proportion of partial ester (component (B)) may be increased. .

Component (B) is (B1) a partial ester having only one free hydroxy group (hereinafter sometimes referred to as "(B1) component"), and/or (B2) having two free hydroxy groups. It may contain a partial ester having the above (hereinafter sometimes referred to as "(B2) component"). The content of component (B2) in component (B) is preferably 70% by mass or more, or 80% by mass or more, based on the total amount of component (B), from the viewpoint of further enhancing the effect of reducing friction under gear lubrication conditions. , or 90% by mass or more, and preferably 99% by mass or less from the viewpoint of ease of production. The content of component (B2) in component (B) can be determined, for example, by using an excess amount of glycerol oligomer (b2) relative to fatty acid (b1) in the condensation reaction, and by subjecting the product obtained by the condensation reaction to column chromatography. It can be adjusted by, for example, purifying by known purification means such as lithography.

The content of component (B) in the lubricating oil composition is 0.05% by mass or more, preferably 0.05% by mass or more, based on the total amount of the composition, from the viewpoint of enhancing the effect of reducing friction on metal surfaces such as gears that are susceptible to high loads. 07% by mass or more, and from the viewpoint of improving storage stability, it is 2.5% by mass or less, and in one embodiment, 0.05 to 2.5% by mass, or 0.07 to 2.5% by mass. could be.

In addition to the component (B), the lubricating oil composition contains glycerin or a glycerin polymer (excluding those corresponding to the above glycerin oligomer (b2)), or a combination thereof, and a fatty acid (the above fatty acid (b1) may correspond to) and a partial ester (hereinafter sometimes referred to as "(B') component") may or may not be contained. In one embodiment, the (B') component can be generated from impurities in the glycerin oligomer (b2). However, the content of component (B') (% by mass based on the total amount of the composition) is preferably less than the content of component (B), preferably the content of component (B) (based on the total amount of the composition) % by weight), or 1/3 or less, or 1/4 or less. In one embodiment, the content of component (B') may be 0 to 0.5% by mass based on the total amount of the composition. From the viewpoint of storage stability, the total content of components (B) and (B') in the lubricating oil composition is preferably 2.5% by mass or less based on the total amount of the composition.

In addition to the component (B), the lubricating oil composition contains glycerin, a glycerin polymer (which may correspond to the glycerin oligomer (b2) above), or a combination thereof, and a fatty acid (the fatty acid (b1) above). (which may be applicable) (hereinafter sometimes referred to as "(B*) component") may or may not be contained. The (B*) component is a compound having no free hydroxy group and may have one or more cyclic ether structures. In one embodiment, the (B*) component can be produced as a by-product in the condensation reaction between the glycerin oligomer (b2) and the fatty acid (b1). However, the content of component (B*) (% by mass based on the total amount of the composition) is preferably less than the content of component (B), preferably the content of component (B) (based on the total amount of the composition) % by weight), or 1/3 or less, or 1/4 or less. In one embodiment, the content of component (B*) may be 0 to 0.5% by mass based on the total amount of the composition.

<(C): Metallic detergent>
In one preferred embodiment, the lubricating oil composition may further contain one or more metallic detergents (hereinafter sometimes referred to as "component (C)"). Examples of component (C) include salicylate detergents, sulfonate detergents, and phenate detergents. In addition, the component (C) may contain only one kind of metallic detergent, or may contain two or more kinds of metallic detergents. In general, in the field of lubricating oils, metallic detergents include organic acid metal salts capable of forming micelles in base oils (for example, alkali or alkaline earth metal alkylsalicylate, alkali or alkaline earth metal alkylbenzene sulfonate, and alkali or alkaline earth metal alkylphenates, etc.), or the organic acid metal salt and a basic metal salt (for example, the alkali or alkaline earth metal hydroxide, carbonate, boron acid salts, etc.) are used. Such organic acids usually have at least one polar group (e.g. carboxy group, sulfo group) having Bronsted acidity capable of forming salts with metal bases (typically metal oxides and/or metal hydroxides). , a phenolic hydroxy group, etc.) and at least one lipophilic group such as a linear or branched alkyl group (for example, a linear or branched alkyl group having 6 or more carbon atoms, etc.) in one molecule.

Examples of salicylate-based detergents include metal salicylates or their basic or overbased salts. Preferred examples of metal salicylates include alkali or alkaline earth metal salicylates represented by the following general formula (1).

In general formula (1), R ¹ each independently represents an alkyl or alkenyl group having 14 to 30 carbon atoms, M represents an alkali metal or alkaline earth metal, a represents 1 or 2, and n represents M It represents 1 or 2 corresponding to the valence. n is 1 when M is an alkali metal and n is 2 when M is an alkaline earth metal. M is preferably an alkaline earth metal. Preferred alkali metals are sodium or potassium, and preferred alkaline earth metals are calcium or magnesium. 1 is preferable as a. When a=2, R ¹ may be a combination of different groups.

A preferred form of the salicylate detergent is an alkaline earth metal salicylate in which a=1 in the general formula (1), or a basic or overbased salt thereof.

Preferred examples of sulfonate-based detergents include alkali or alkaline earth metal salts of alkylaromatic sulfonic acids obtained by sulfonating alkylaromatic compounds, or their basic salts or overbased salts, more preferably alkali Mention may be made of earth metal salts or their basic or overbased salts. The weight average molecular weight of the alkylaromatic compound is preferably 400-1500, more preferably 700-1300.
Preferred alkali metals are sodium or potassium, and preferred alkaline earth metals are calcium or magnesium. Examples of alkylaromatic sulfonic acids include so-called petroleum sulfonic acids and synthetic sulfonic acids. Examples of petroleum sulfonic acids include those obtained by sulfonating alkylaromatic compounds in lubricating oil fractions of mineral oils, and so-called mahogany acid, which is a by-product of white oil production. An example of a synthetic sulfonic acid is a linear or branched alkyl obtained by recovering a by-product in an alkylbenzene production plant, which is a raw material for detergents, or by alkylating benzene with a polyolefin. A sulfonated alkylbenzene having a group can be mentioned. Another example of the synthetic sulfonic acid is a sulfonated alkylnaphthalene such as dinonylnaphthalene. The sulfonating agent for sulfonating these alkylaromatic compounds is not particularly limited, and for example, fuming sulfuric acid or sulfuric anhydride can be used.

Preferable examples of phenate-based detergents include overbased salts of alkali or alkaline earth metal salts of compounds having the structure represented by the following general formula (2), more preferably overbased salts of alkaline earth metal salts. can be mentioned. Preferred alkali metals are sodium or potassium, and preferred alkaline earth metals are calcium or magnesium.

In general formula (2), R ² represents a linear or branched, saturated or unsaturated alkyl or alkenyl group having 6 to 21 carbon atoms, m represents the degree of polymerization and represents an integer of 1 to 10, and A represents a sulfide (--S--) group or a methylene (--CH ₂ --) group, and x represents an integer of 1-3. R ² may be a combination of two or more different groups.

The number of carbon atoms in R ² in general formula (2) is preferably 9 or more from the viewpoint of enhancing the solubility in the base oil, and is preferably 18 or less, more preferably 15 or less from the viewpoint of ease of production. may be 9-18, or 9-15 in embodiments of

The degree of polymerization m in general formula (2) is preferably 1-4.

Metallic detergents may be overbased with carbonates (e.g., alkali metal carbonates such as sodium carbonate or potassium carbonate, or alkaline earth metal carbonates such as calcium carbonate or magnesium carbonate), or may be overbased with boric acid. It may be overbased with a salt (for example, an alkali metal borate such as sodium borate or potassium borate, or an alkaline earth metal borate such as calcium borate or magnesium borate).

In one embodiment, component (C) is one or more overbased calcium or magnesium sulfonate detergents, one or more overbased calcium or magnesium salicylate detergents, and/or one or more overbased It may contain calcium or magnesium phenate detergents, preferably one or more overbased calcium sulfonate detergents, and/or one or more overbased calcium salicylate detergents. Calcium sulfonate detergents, calcium salicylate detergents, and calcium phenate detergents are each preferably overbased with calcium carbonate, and magnesium sulfonate detergents, magnesium salicylate detergents, and magnesium phenate detergents are each preferably carbonated detergents. It is preferably overbased with magnesium.

The base number of the metallic detergent can be appropriately determined according to the use of the lubricating oil composition. For example, when the lubricating oil composition is used for lubricating gear devices such as transmissions (e.g., manual transmissions, automatic transmissions, continuously variable transmissions, etc.), the base number of the metallic detergent is , It is preferably 200 mgKOH / g or more, more preferably 250 mgKOH / g or more from the viewpoint of increasing the seizure resistance and the transmission torque capacity of the wet clutch, and from the same viewpoint, preferably 600 mgKOH / g or less, more preferably 550 mgKOH / g or less, and in one embodiment may be 200-600 mg KOH/g, or 250-550 mg KOH/g. Further, for example, when the lubricating oil composition is used for lubricating an internal combustion engine, it is preferably 0 mgKOH/g or more, more preferably 20 mgKOH/g or more, from the viewpoint of improving the detergency performance and the base number maintenance property. From the viewpoint of suppressing the ash content and the life of the exhaust gas post-treatment device, it is preferably 500 mgKOH / g or less, more preferably 450 mgKOH / g or less, and in one embodiment 0 to 500 mgKOH / g, or 20 to 450 mgKOH / g can be The term "base number" as used herein means a base number measured by the perchloric acid method according to JIS K2501.

When the lubricating oil composition contains component (C), its content can be appropriately determined according to the use of the lubricating oil composition. For example, when the lubricating oil composition is used for lubricating 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 (C) in the lubricating oil composition The amount is preferably 200 mass ppm or more, more preferably 250 mass ppm or more as a metal content based on the total amount of the composition, from the viewpoint of increasing wear resistance, seizure resistance, fatigue resistance, and transmission torque capacity of a wet clutch. Yes, and from the viewpoint of improving fuel economy and fatigue resistance, it is preferably 600 mass ppm or less, more preferably 550 mass ppm or less, and in one embodiment, 200 to 600 mass ppm, or 250 to 550 mass ppm. could be. Further, for example, when the lubricating oil composition is used for lubricating an internal combustion engine, the content of the component (C) is preferably the amount of metal based on the total amount of the composition, from the viewpoint of improving the cleaning performance and the ability to maintain the base number. It is 500 mass ppm or more, more preferably 1000 mass ppm or more, and preferably 10000 mass ppm or less, more preferably 5000 mass ppm or less from the viewpoint of suppressing ash in the composition and the life of the exhaust gas post-treatment device. Yes, in one embodiment it can be from 500 to 10000 ppm by weight, or from 1000 to 5000 ppm by weight.

<(D) Ashless Dispersant>
In one preferred embodiment, the lubricating oil composition may further contain one or more ashless dispersants (hereinafter sometimes referred to as "component (D)"). Generally, in the lubricating oil field, ashless dispersants include at least one long-chain (e.g., 40 or more carbon atoms) linear or branched aliphatic hydrocarbon group and at least one polyamine chain (typically polyethyleneamine A nitrogen-containing compound or a modified product (derivative) thereof is used in which a part of the nitrogen atoms of the polyamine chain may be acylated. Examples of modified products are described below.

As component (D), for example, one or more compounds selected from the following (D-1) to (D-3) can be used.
(D-1) a succinimide having at least one alkyl group or alkenyl group in the molecule or a modified product (derivative) thereof (hereinafter sometimes referred to as "component (D-1)");
(D-2) benzylamine having at least one alkyl group or alkenyl group in the molecule or a modified product (derivative) thereof (hereinafter sometimes referred to as "component (D-2)");
(D-3) A polyamine having at least one alkyl group or alkenyl group in the molecule or a modified product (derivative) thereof (hereinafter sometimes referred to as "component (D-3)").

Component (D-1) is particularly preferably used as component (D).
Among component (D-1), examples of succinimide having at least one alkyl or alkenyl group in the molecule include alkyl or alkenyl succinic acid having an alkyl or alkenyl group having 40 to 400 carbon atoms or its anhydride. and condensation reaction products of polyamines. Such a condensation reaction product (condensation product) can be represented, for example, by the following general formula (3) or (4).

In general formula (3), R ³ 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 one exemplary embodiment, compounds of general formula (3) are obtained as a mixture of compounds with different b. The carbon number of R ³ is 40 or more, preferably 60 or more from the viewpoint of solubility in base oil, and 400 or less, preferably 350 or less, more preferably 250 or less from the viewpoint of low-temperature fluidity of the composition. Yes, and in one embodiment can be 40-400, or 60-350, or 60-250.

In general formula (4), R ⁴ and R ⁵ each independently represent an alkyl group or alkenyl group having 40 to 400 carbon atoms, and may be a combination of different groups. Also, c represents an integer of 0 to 15, preferably 1 to 13, more preferably 1 to 11. In one exemplary embodiment, compounds of general formula (4) are obtained as a mixture of compounds with different c. The carbon number of R ⁴ and R ⁵ is 40 or more, preferably 60 or more from the viewpoint of solubility in base oil, and 400 or less, preferably 350 or less, more preferably 350 or less from the viewpoint of low-temperature fluidity of the composition. 250 or less, and in one embodiment may be 40-400, or 60-350, or 60-250.

Alkyl or alkenyl groups (R ³ to R ⁵ ) in general formulas (3) and (4) may be linear or branched. Preferred examples thereof include branched alkyl groups and branched alkenyl groups derived from olefin oligomers such as propylene, 1-butene and isobutene, and co-oligomers of ethylene and propylene. Among them, branched alkyl or alkenyl groups derived from oligomers of isobutene, commonly called polyisobutylene, and polybutenyl groups are most preferred.
A suitable number average molecular weight of the alkyl or alkenyl groups (R ³ to R ⁵ ) in general formulas (3) and (4) is 800-3500, preferably 900-3500.

Succinimides having at least one alkyl group or alkenyl group in the molecule include so-called mono-type succinimides represented by general formula (3) in which only one end of a polyamine chain is imidized. , a so-called bis-type succinimide represented by the general formula (4) in which both ends of a polyamine chain are imidized. The lubricating oil composition may contain both mono-type succinimides and bis-type succinimides, or both as a mixture. The content of bis-type succinimide or modified product thereof in component (D-1) is preferably 50 to 100% by mass, more preferably 50 to 100% by mass, based on the total amount of component (D-1) (100% by mass). 70 to 100% by mass.

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

Examples of modified products (modified compounds, derivatives) in components (D-1) to (D-3) include (i) modified products with oxygen-containing organic compounds, (ii) modified products with boric acid, (iii) phosphorus acid-modified, (iv) sulfur-modified, and (v) modified by a combination of two or more of these modifications.
(i) A modified product with an oxygen-containing organic compound is a succinimide, benzylamine or polyamine having at least one alkyl group or alkenyl group in the molecule (hereinafter referred to as "the above-mentioned nitrogen-containing compound"), and fatty acid monocarboxylic acids having 1 to 30 carbon atoms, polycarboxylic acids having 2 to 30 carbon atoms (eg, oxalic acid, phthalic acid, trimellitic acid, pyromellitic acid, etc.), anhydrides or ester compounds thereof, carbon number It is a modified compound in which some or all of the remaining amino groups and/or imino groups are neutralized or amidated by the action of 2 to 6 alkylene oxides or hydroxy(poly)oxyalkylene carbonates.
(ii) The boric acid-modified product is a modified compound in which some or all of the remaining amino groups and/or imino groups are neutralized or amidated by reacting boric acid on the nitrogen-containing compound. .
(iii) Phosphoric acid-modified compounds are modified compounds in which some or all of the remaining amino groups and/or imino groups are neutralized or amidated by reacting the nitrogen-containing compound with phosphoric acid. .
(iv) A sulfur-modified compound is a modified compound obtained by reacting a sulfur compound on the nitrogen-containing compound described above.
(v) A modified compound obtained by a combination of two or more modifications is a combination of the nitrogen-containing compound described above and two or more modifications selected from modification with an oxygen-containing organic compound, boric acid modification, phosphoric acid modification, and sulfur modification. It can be obtained by applying
Among these modified products (derivatives) of (i) to (v), boric acid-modified compounds of alkenylsuccinimides, particularly boric acid-modified bis-type alkenylsuccinimides can be preferably used.

When the lubricating oil composition contains component (D), its content can be appropriately determined according to the use of the lubricating oil composition. For example, when the lubricating oil composition is used for lubricating a gear device such as a transmission (e.g., manual transmission, automatic transmission, continuously variable transmission, etc.), the content of component (D) in the lubricating oil composition The amount is preferably 0.1% by mass or more based on the total amount of the composition from the viewpoint of enhancing oxidation stability, and is preferably 10% by mass or less, more preferably 5% by mass or less from the viewpoint of maintaining energy saving. be. Further, for example, when the lubricating oil composition is used for lubricating an internal combustion engine, the content of the component (D) is preferably 0.5% by mass or more, based on the total amount of the composition, from the viewpoint of improving coking resistance. It is preferably 1.0% by mass or more, and from the viewpoint of maintaining fuel efficiency, it is preferably 10.0% by mass or less, more preferably 5.0% by mass or less, and in one embodiment, 0.5% by mass. ~10.0% by weight, or between 1.0% and 5.0% by weight.

As component (D), component (D-1) can be preferably used, and as component (D), modified boric acid can be preferably used. In one embodiment, component (D) may be at least one unmodified (D-1) component (unmodified succinimide dispersant), and at least one (D-1) component It may be a boric acid-modified product (boric acid-modified succinimide dispersant), which is a combination of one or more unmodified succinimide dispersants and one or more boric acid-modified succinimide dispersants. may Component (D) may or may not contain modified boric acid, but from the viewpoint of sludge dispersibility, The ratio (B/N) to the content N as nitrogen content may preferably range from 0 to 1.0 in one embodiment.

<(E) Phosphorus-containing anti-wear agent>
In one 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), a phosphorus-containing antiwear agent used in lubricating oils can be used without particular limitation. Examples of phosphorus-containing antiwear agents include compounds represented by the following general formula (5), compounds represented by the following general formula (6), and metal salts and ammonium salts thereof.

（一般式（５）中、Ｘ^１、Ｘ^２、及びＸ^３は、それぞれ独立に酸素原子または硫黄原子を表し；Ｒ^６は硫黄原子を含んでいてもよい炭素数１～３０の炭化水素基を表し；Ｒ^７及びＲ^８はそれぞれ独立に硫黄原子を含んでいてもよい炭素数１～３０の炭化水素基または水素原子を表し；Ｒ^６、Ｒ^７、及びＲ^８は同一でも相互に異なっていてもよい。Ｒ^７及び／又はＲ^８が水素原子である場合、一般式（５）の化合物はそのいかなるタウトマーも包含するものとする。）

(in the general formula (5), X ¹ , X ² and X ³ each independently represent an oxygen atom or a sulfur atom; R ⁶ is a hydrocarbon group having 1 to 30 carbon atoms which may contain a sulfur atom; R ⁷ and R ⁸ each independently represent a hydrocarbon group having 1 to 30 carbon atoms which may contain a sulfur atom or a hydrogen atom; R ⁶ , R ⁷ and R ⁸ are the same or different (If R ⁷ and/or R ⁸ is a hydrogen atom, the compound of general formula (5) shall include any tautomer thereof.)

（一般式（６）中、Ｘ^４、Ｘ^５、Ｘ^６、及びＸ^７は、それぞれ独立に酸素原子または硫黄原子を表し；Ｒ^９は硫黄原子を含んでいてもよい炭素数１～３０の炭化水素基を表し；Ｒ^１０及びＲ^１１はそれぞれ独立に硫黄原子を含んでいてもよい炭素数１～３０の炭化水素基または水素原子を表し；Ｒ^９、Ｒ^１０、及びＲ^１１は同一でも相互に異なっていてもよい。）

(In general formula (6), X ⁴ , X ⁵ , X ⁶ and X ⁷ each independently represent an oxygen atom or a sulfur atom; R ⁹ is a C 1-30 represents a hydrocarbon group; R ¹⁰ and R ¹¹ each independently represent a hydrocarbon group having 1 to 30 carbon atoms which may contain a sulfur atom or a hydrogen atom; R ⁹ , R ¹⁰ and R ¹¹ may be the same may differ from each other.)

Examples of hydrocarbon groups having 1 to 30 carbon atoms in general formulas (5) and (6) include alkyl groups, cycloalkyl groups, alkenyl groups, alkyl-substituted cycloalkyl groups, aryl groups, alkyl-substituted aryl groups, and aryl An alkyl group etc. can be mentioned. 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, more preferably 4 to 12 carbon atoms, It is an aryl group or an alkylaryl group.

The hydrocarbon group having 1 to 30 carbon atoms in the general formulas (5) and (6) may be a hydrocarbon group containing a sulfur atom or a hydrocarbon group containing no sulfur atom.

In one embodiment, preferred examples of hydrocarbon groups containing no sulfur atom include linear alkyl groups having 4 to 18 carbon atoms. Examples of linear alkyl groups include butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl and heptadecyl groups. , an octadecyl group.

Examples of hydrocarbon groups containing a sulfur atom include hydrocarbon groups functionalized with sulfide bonds. Preferred examples of the hydrocarbon group functionalized with a sulfide bond include groups having 4 to 20 carbon atoms represented by the following general formula (7).

一般式（７）において、Ｒ^１２は炭素数２～１７の直鎖炭化水素基であり、好ましくはエチレン基またはプロピレン基であり、一の実施形態においてエチレン基である。Ｒ^１３は炭素数２～１７の直鎖炭化水素基であり、好ましくは炭素数２～１６の直鎖炭化水素基であり、特に好ましくは炭素数６～１０の直鎖炭化水素基である。

In general formula (7), R ¹² is a linear hydrocarbon group having 2 to 17 carbon atoms, preferably an ethylene group or a propylene group, and in one embodiment, an ethylene group. R ¹³ is a linear hydrocarbon group having 2 to 17 carbon atoms, preferably a linear hydrocarbon group having 2 to 16 carbon atoms, and particularly preferably a linear hydrocarbon group having 6 to 10 carbon atoms.

Preferred examples of the group represented by formula (7) include 3-thiapentyl group, 3-thiahexyl group, 3-thiaheptyl group, 3-thiaoctyl group, 3-thianonyl group, 3-thiadecyl group, and 3-thiaundecyl group. , 4-thiahexyl group, and the like.

Examples of the metal that forms a metal salt with the phosphorus compound represented by the general formula (5) or (6) include alkali metals such as lithium, sodium, potassium and cesium, and alkaline earth metals such as calcium, magnesium and barium. , zinc, copper, iron, lead, nickel, silver and manganese. Among these, alkaline earth metals such as calcium and magnesium, zinc, or combinations thereof are preferred.

Examples of nitrogen-containing compounds that form an ammonium salt with the phosphorus compound represented by formula (5) or (6) include ammonia, monoamines, diamines, polyamines, and alkanolamines. More specifically, nitrogen-containing compounds represented by the following general formula (8); alkylenediamines such as methylenediamine, ethylenediamine, propylenediamine, and butylenediamine; diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine and combinations thereof, and the like.

（一般式（８）中、Ｒ^１４～Ｒ^１６はそれぞれ独立に、水素原子、炭素数１～８のヒドロカルビル基、又は水酸基を有する炭素数１～８のヒドロカルビル基を表し；Ｒ^１４～Ｒ^１６のうち少なくとも１つは炭素数１～８のヒドロカルビル基、又は水酸基を有する炭素数１～８のヒドロカルビル基である。）

(In general formula (8), R ¹⁴ to R ¹⁶ each independently represent a hydrogen atom, a hydrocarbyl group having 1 to 8 carbon atoms, or a hydrocarbyl group having 1 to 8 carbon atoms and having a hydroxyl group; R ¹⁴ to R ¹⁶ at least one of which is a hydrocarbyl group having 1 to 8 carbon atoms or a hydrocarbyl group having 1 to 8 carbon atoms having a hydroxyl group.)

Preferred examples of the compound represented by the above general formula (5) include X ¹ to X ³ in the above general formula (5) being oxygen atoms, and R ⁶ to R ⁸ each independently containing a sulfur atom. A phosphite ester compound which is an alkyl group (preferably 4-12) having 3 to 18 carbon atoms (preferably 4 to 12), an aryl group (eg, phenyl group, etc.), or an alkylaryl group (eg, alkylphenyl group, etc.); In formula (5), X ¹ to X ³ are oxygen atoms, R ⁶ and R ⁷ are each independently an alkyl group having 3 to 18 carbon atoms (preferably 4 to 12 carbon atoms) optionally containing a sulfur atom, an aryl (eg, phenyl group, etc.), or ^an alkylaryl group (eg, alkylphenyl group ^, etc.), wherein R ⁸ is hydrogen; Two of which are oxygen atoms and the other one is a sulfur atom, and R ⁶ and R ⁷ are each independently an alkyl group or aryl group having 3 to 18 (preferably 4 to 12) carbon atoms which may contain a sulfur atom (for example phenyl group, etc.), or an alkylaryl group (e.g., alkylphenyl group, etc.), wherein R ⁸ is hydrogen; and one of X ¹ to X ³ in the general formula (5) is An oxygen atom, the remaining two are sulfur atoms, and R ⁶ and R ⁷ are each independently an alkyl group or aryl group (e.g., phenyl group etc.), or a hydrogendithiophosphite compound which is an alkylaryl group ⁽ eg, an alkylphenyl group, etc.) and R8 is hydrogen.
A preferred example of the compound represented by the general formula (6) is that two of X ⁴ to X ⁷ in the general formula (6) are sulfur atoms, the remaining two are oxygen atoms, and R ⁹ to R ¹¹ are A dithiophosphate compound which is an alkyl group, an aryl group, or an alkylaryl group having 3 to 18 carbon atoms (preferably 4 to 12 carbon atoms) each independently optionally containing a sulfur atom can be mentioned.
These compounds may be used individually by 1 type, and may be used in combination of 2 or more type.

One example of component (E) is zinc dialkyldithiophosphate (ZnDTP). Examples of zinc dialkyldithiophosphates include compounds represented by the following general formula (9).

一般式（９）中、Ｒ^１７～Ｒ^２０は、それぞれ独立に炭素数３～１８の直鎖または分岐鎖のアルキル基を表し、異なる基の組み合わせであってもよい。また、Ｒ^１７～Ｒ^２０の炭素数は好ましくは３～１２、より好ましくは３～８である。また、Ｒ^１７～Ｒ^２０は、第１級アルキル基、第２級アルキル基、及び第３級アルキル基のいずれであってもよいが、第１級アルキル基もしくは第２級アルキル基またはそれらの組み合わせであることが好ましい。

In general formula (9), R ¹⁷ to R ²⁰ each independently represent a linear or branched alkyl group having 3 to 18 carbon atoms, and may be a combination of different groups. In addition, R ¹⁷ to R ²⁰ preferably have 3 to 12 carbon atoms, more preferably 3 to 8 carbon atoms. In addition, R ¹⁷ to R ²⁰ may be any of a primary alkyl group, a secondary alkyl group and a tertiary alkyl group. A combination is preferred.

When the lubricating oil composition contains component (E), its content can be appropriately determined according to the use of the lubricating oil composition. For example, when the lubricating oil composition is used for lubricating 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 (E) in the lubricating oil composition The amount is preferably 50 ppm by mass or more, more preferably 100 ppm by mass or more in terms of phosphorus content based on the total amount of the composition, from the viewpoint of improving wear resistance, seizure resistance, bearing fatigue life, and shift shock prevention, From the same point of view, it is preferably 800 mass ppm or less, more preferably 700 mass ppm or less, and in one embodiment, it may be 50 to 800 mass ppm, or 100 to 700 mass ppm. Further, for example, when the lubricating oil composition is used for lubricating an internal combustion engine, the content of the component (E) is preferably 400 mass ppm or more as a phosphorus content based on the total amount of the composition, from the viewpoint of improving wear resistance. It is more preferably 500 mass ppm or more, preferably 5000 mass ppm or less, more preferably 3000 mass ppm or less from the viewpoint of reducing catalyst poisoning of the exhaust gas post-treatment device, and in one embodiment, 400 to 5000 mass ppm. , or from 500 to 3000 ppm by weight.

<(F) Sulfur-containing extreme pressure agent>
In one preferred embodiment, the gear oil composition may further contain one or more sulfur-containing extreme pressure agents (hereinafter sometimes referred to as "(F) component") other than the (E) component. Examples of component (F) include thiadiazole compounds, dihydrocarbyl (poly)sulfides, sulfurized fats and oils, sulfurized fatty acids, sulfurized esters, sulfurized olefins, alkylthiocarbamoyl compounds, thiocarbamate compounds, thioterpene compounds, dialkylthiodipropionate compounds, sulfurized Known sulfur-containing extreme pressure agents such as mineral oil, zinc dithiocarbamate compounds and molybdenum dithiocarbamate compounds can be mentioned.

Preferred examples of the thiadiazole compound include a 1,3,4-thiadiazole compound represented by the following general formula (10), a 1,2,4-thiadiazole compound represented by the following general formula (11), and the following general formula: A 1,2,3-thiadiazole compound represented by (12) can be mentioned.

（一般式（１０）～（１２）中、Ｒ^２１及びＲ^２２は同一でも異なっていてもよく、それぞれ独立に水素原子または炭素数１～２０のヒドロカルビル基を表し；ｈ及びｉは同一でも異なっていてもよく、それぞれ独立に０～８の整数を表す。）

(In general formulas (10) to (12), R ²¹ and R ²² may be the same or different and each independently represents a hydrogen atom or a hydrocarbyl group having 1 to 20 carbon atoms; h and i are the same or different; each independently represents an integer from 0 to 8.)

Dihydrocarbyl (poly)sulfide is a compound represented by the following general formula (13). Here, when R ²³ and R ²⁴ are alkyl groups, it may be referred to as alkyl sulfide.

（一般式（１３）中、Ｒ^２３及びＲ^２４は同一でも異なっていてもよく、それぞれ独立に炭素数１～２０のアルキル基（直鎖でも分岐鎖でもよく、環状構造を有していてもよい。）、炭素数６～２０のアリール基、炭素数７～２０のアルキルアリール基、又は炭素数７～２０のアリールアルキル基を表し、ｊは１～８の整数を表す。）

(In the general formula (13), R ²³ and R ²⁴ may be the same or different, and are each independently an alkyl group having 1 to 20 carbon atoms (which may be linear or branched, and may have a cyclic structure. ), represents an aryl group having 6 to 20 carbon atoms, an alkylaryl group having 7 to 20 carbon atoms, or an arylalkyl group having 7 to 20 carbon atoms, and j represents an integer of 1 to 8.)

When the lubricating oil composition contains component (F), its content can be appropriately determined according to the use of the lubricating oil composition. For example, when the lubricating oil composition is used for lubricating 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 (F) in the lubricating oil composition The amount is preferably 200 ppm by mass or more, more preferably 300 ppm by mass or more as a sulfur content based on the total amount of the composition, from the viewpoint of improving extreme pressure properties and fatigue resistance. From the viewpoint of enhancing stability, it is preferably 3000 mass ppm or less, more preferably 2500 mass ppm or less, and may be 200 to 3000 mass ppm or 300 to 2500 mass ppm in one embodiment. Further, 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 as sulfur content based on the total amount of the composition, from the viewpoint of improving extreme pressure properties and fatigue resistance. ppm or more, more preferably 30 mass ppm or more, and preferably 200 mass ppm or less, more preferably 100 mass ppm or less from the viewpoint of reducing catalyst poisoning of the exhaust gas post-treatment device. It can be ~200 ppm by weight, or 30-100 ppm by weight.

<(G) Antioxidant>
In one preferred embodiment, the lubricating oil composition contains one or more amine-based antioxidants and/or one or more A phenolic antioxidant may be further included.

Examples of amine antioxidants include aromatic amine antioxidants and hindered amine antioxidants. Examples of aromatic amine antioxidants include primary aromatic amine compounds such as alkylated α-naphthylamine; - secondary aromatic amine compounds such as naphthylamine; As the aromatic amine-based antioxidant, alkylated diphenylamine, alkylated phenyl-α-naphthylamine, or a combination thereof can be preferably used.

Examples of hindered amine antioxidants include compounds having a 2,2,6,6-tetraalkylpiperidine skeleton (2,2,6,6-tetraalkylpiperidine derivatives). As the 2,2,6,6-tetraalkylpiperidine derivative, a 2,2,6,6-tetraalkylpiperidine derivative having a substituent at the 4-position is preferred. Also, two 2,2,6,6-tetraalkylpiperidine skeletons may be bonded via their respective 4-position substituents. Also, 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 2,2,6,6-tetramethylpiperidine skeleton.

The 4-position substituent of the 2,2,6,6-tetraalkylpiperidine skeleton includes an acyloxy group (R ²⁵ COO-), an alkoxy group (R ²⁵ O-), an alkylamino group (R ²⁵ NH-), acylamino group (R ²⁵ CONH-), and the like. R ²⁵ is preferably a hydrocarbon group having 1 to 30 carbon atoms, more preferably 1 to 24 carbon atoms, still more preferably 1 to 20 carbon atoms. Examples of hydrocarbon groups include alkyl groups, alkenyl groups, cycloalkyl groups, alkylcycloalkyl groups, aryl groups, alkylaryl groups, and arylalkyl groups.

When two 2,2,6,6-tetraalkylpiperidine skeletons are bonded via their respective 4-position substituents, the substituents are hydrocarbylenebis(carbonyloxy) groups (-OOC- R ²⁵ -COO-), hydrocarbylenediamino group (-HN-R ²⁵ -NH-), hydrocarbylenebis(carbonylamino) group (-HNCO-R ²⁵ -CONH-), and the like. R ²⁵ is preferably a hydrocarbylene group having 1 to 30 carbon atoms, more preferably an alkylene group.

As the 4-position substituent of the 2,2,6,6-tetraalkylpiperidine skeleton, an acyloxy group is preferred. Examples of compounds having an acyloxy group at the 4-position of the 2,2,6,6-tetraalkylpiperidine skeleton include esters of 2,2,6,6-tetramethyl-4-piperidinol and carboxylic acids. can be done. Examples of the carboxylic acid include linear or branched aliphatic carboxylic acids having 8 to 20 carbon atoms.

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′-butylidenebis(3-methyl-6-tert-butylphenol); 4,4′-isopropylidenebis(2,6-di-tert-butylphenol); 2,2′-methylenebis(4-methyl-6 -nonylphenol); 2,2′-isobutylidenebis(4,6-dimethylphenol); 2,2′-methylenebis(4-methyl-6-cyclohexylphenol); 2,6-di-tert-butyl-4 -methylphenol; 2,6-di-tert-butyl-4-ethylphenol; 2,4-dimethyl-6-tert-butylphenol; 2,6-di-tert-butyl-4-(N,N'-dimethyl aminomethyl)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)propionic acid esters; 3-methyl-5-tert-butyl-4-hydroxyphenol fatty acid esters, hindered phenol compounds and bisphenol compounds can be done.

When the lubricating oil composition contains the (G) component, its content can be appropriately determined according to the use of the lubricating oil composition. For example, when the lubricating oil composition is used for lubricating a gear device such as a transmission (e.g., manual transmission, automatic transmission, continuously variable transmission, etc.), the content of the component (G) in the lubricating oil composition The amount is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, based on the total amount of the composition, from the viewpoint of enhancing thermal oxidation stability, and preferably 2.0% by mass or less from the same viewpoint. More preferably, it is 1.0% by mass or less, and in one embodiment, it may be 0.1 to 2.0% by mass, or 0.2 to 1.0% by mass. Further, for example, when the lubricating oil composition is used for lubricating an internal combustion engine, the content of the component (G) in the lubricating oil composition is preferably 0 based on the total amount of the composition, from the viewpoint of enhancing thermal oxidation stability. .1% by mass or more, more preferably 0.5% by mass or more, and from the same viewpoint, preferably 5.0% by mass or less, more preferably 3.0% by mass or less, and in one embodiment, 0.1% by mass. ~5.0 wt%, or 0.5 to 3.0 wt%.

<(H) Viscosity index improver>
In one preferred embodiment, the lubricating oil composition further contains one or more polymers having a viscosity index improving action (hereinafter sometimes referred to as "viscosity index improver" or "component (H)"). obtain. Examples of component (H) include non-dispersed or dispersed poly(meth)acrylates, (meth)acrylate-olefin copolymers, non-dispersed or dispersed ethylene-α-olefin copolymers or hydrides thereof, Examples include polyisobutylene or hydrogenated products thereof, styrene-diene hydrogenated copolymers, styrene-maleic anhydride ester copolymers, and polyalkylstyrenes. In addition, in this specification, "(meth)acrylate" means "acrylate and/or methacrylate." As the component (H), one type of polymer may be used alone, or two or more types of polymers may be used in combination.

In one embodiment, as component (H), dispersed poly(meth)acrylate, non-dispersed poly(meth)acrylate, or a combination thereof can be preferably used. In one embodiment, dispersed poly(meth)acrylates can be preferably used. In this specification, a dispersing poly(meth)acrylate compound has a functional group containing a nitrogen atom, whereas a non-dispersing poly(meth)acrylate compound does not have a functional group containing a nitrogen atom.

In one embodiment, as the poly(meth)acrylate viscosity index improver, the ratio of the structural unit represented by the following general formula (14) to the total monomer units in the polymer is 10 to 90 mol%. Poly(meth)acrylate (hereinafter sometimes referred to as “poly(meth)acrylate (H1)” or simply “(H1) component”) can be preferably used.

（一般式（１４）中、Ｒ^２６は水素又はメチル基を表し、Ｒ^２７は炭素数１～３６の直鎖又は分岐鎖の炭化水素基、好ましくはアルキル基を表す。）

(In general formula (14), R ²⁶ represents hydrogen or a methyl group, and R ²⁷ represents a straight or branched hydrocarbon group having 1 to 36 carbon atoms, preferably an alkyl group.)

The weight average molecular weight of component (H) can be appropriately determined according to the use of the lubricating oil composition. For example, when the lubricating oil composition is used for lubricating a gear device such as a transmission (e.g., manual transmission, automatic transmission, continuously variable transmission, etc.), the weight average molecular weight of the component (H) is the viscosity index It is preferably 10,000 or more, more preferably 20,000 or more, and still more preferably 30,000 or more from the viewpoint of enhancing the improvement effect and improving low-temperature viscosity characteristics. And from the viewpoint of increasing shear stability, it is preferably 200,000 or less, more preferably 150,000 or less, and still more preferably 100,000 or less. ~150,000, or 30,000 to 100,000. Further, 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 from the viewpoint of enhancing the effect of improving the viscosity index and improving low-temperature viscosity characteristics and fuel economy. ,000 or more, more preferably 200,000 or more, and from the viewpoint of improving oil solubility, storage stability, and shear stability, preferably 1,000,000 or less, more preferably 700,000 or less. Yes, and in one embodiment can be from 100,000 to 1,000,000, or from 200,000 to 700,000.

When the lubricating oil composition contains component (H), its content can be appropriately determined as an amount that provides the desired kinematic viscosity and viscosity-temperature characteristics of the lubricating oil composition as a whole. For example, the viscosity index is an index for evaluating viscosity-temperature characteristics. For example, when the lubricating oil composition is used for lubricating 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 (H) in the lubricating oil composition The amount is, for example, 0.1% by mass or more, or 0.5% by mass or more as a resin content based on the total amount of the composition, from the viewpoint of improving viscosity-temperature characteristics and enhancing energy saving, and from the viewpoint of improving shear stability. For example, it may be 22 wt% or less, or 12 wt% or less, in one embodiment from 0.1 to 22 wt%, or from 0.5 to 12 wt%. Further, for example, when the lubricating oil composition is used for lubrication of an internal combustion engine, the content of the (H) component in the lubricating oil composition is, from the viewpoint of improving fuel efficiency, the resin content based on the total amount of the composition, for example 0.1% by mass or more, or 0.5% by mass or more, and from the viewpoint of improving shear stability, for example, 20% by mass or less, or 15% by mass or less, and in one embodiment, 0.1 to 20% by mass, or 0 .5 to 15% by weight. In this specification, the resin component means a polymer component having a molecular weight of 1,000 or more.

(Other additives)
The lubricating oil composition of the present invention comprises (I) a friction modifier other than the above components (B) and (B'), (B*) and (F), and (J) other than the above component (H). (K) a corrosion inhibitor other than the above component (F); (L) a metal deactivator other than the above component (F); (M) the above components (B) and (B'); It may further contain one or more additives selected from antirust agents other than the component (B*), (N) demulsifiers, (O) antifoaming agents, and (P) colorants.

(I) As a friction modifier (hereinafter sometimes referred to as "(I) component") other than the above components (B), (B'), (B*) and (F), lubricating oil An oil-soluble organic molybdenum compound or an oil-based friction modifier used as a friction modifier in the above, using a compound other than the above components (B) and (B') and (B*) and (F) be able to. Examples of such compounds include oil-soluble organic molybdenum compounds other than molybdenum dithiocarbamate described above as examples of component (F), and components other than components (B), (B'), and (B*). oily agent-based friction modifiers.
When the lubricating oil composition contains component (I), its content may be, for example, 0.1 to 1.0% by mass based on the total amount of the composition.

(J) Pour point depressants other than the above component (H) (hereinafter sometimes referred to as "component (J)") include, for example, ethylene vinyl acetate, etc., depending on the properties of the lubricating base oil used. A known pour point depressant can be used. When the lubricating oil composition contains component (J), its content may be, for example, 0.01 to 1.0% by mass based on the total amount of the composition.

(K) Corrosion inhibitors other than the above component (F) (hereinafter sometimes referred to as "component (K)") include known corrosion inhibitors such as benzotriazole-based compounds, tolyltriazole-based compounds, and imidazole-based compounds. Inhibitors can be used. When the lubricating oil composition contains component (K), its content may be, for example, 0.005 to 5.0% by mass based on the total amount of the composition.

(L) Metal deactivators other than component (F) (hereinafter sometimes referred to as "(L) component") include, for example, imidazolines, pyrimidine derivatives, mercaptobenzothiazole, benzotriazole and derivatives thereof, Known metal deactivators such as 2-(alkyldithio)benzimidazoles and β-(o-carboxybenzylthio)propiononitrile can be used. When the lubricating oil composition contains component (L), its content may be, for example, 0.005 to 1.0% by mass based on the total amount of the composition.

(M) Rust inhibitors other than the above components (B), (B') and (B*) (hereinafter sometimes referred to as "(M) component") include, for example, petroleum sulfonate, alkylbenzene sulfonate, Known rust inhibitors such as dinonyl naphthalene sulfonates, alkenyl succinic acid esters, and polyhydric alcohol esters (excluding those corresponding to the above component (B), (B'), or (B*)) Available. 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 composition.

(N) As the demulsifier, for example, a known demulsifier such as a polyalkylene glycol-based nonionic surfactant can be used. When the lubricating oil composition contains a demulsifier, its content may be, for example, 0.005 to 5.0% by mass based on the total amount of the composition.

(O) As the antifoaming agent, for example, known antifoaming agents such as silicone, fluorosilicone, and fluoroalkyl ether can be used. When the lubricating oil composition contains an antifoaming agent, its content may be, for example, 0.0005 to 1.0% by mass based on the total amount of the composition.

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

<Lubricating oil composition>
The kinematic viscosity at 100°C of the lubricating oil composition can be appropriately determined according to the use of the lubricating oil composition. For example, when the lubricating oil composition is used for lubricating a gear device such as a transmission (e.g., manual transmission, automatic transmission, continuously variable transmission, etc.), the kinematic viscosity at 100 ° C. of the lubricating oil composition is From the viewpoint of improving wear resistance, it is preferably 2.0 mm ² /s or more, more preferably 2.5 mm ² /s or more, and from the viewpoint of improving energy saving, it is preferably 8.0 mm ² /s or less, more preferably 7.0 mm ² /s or less, in one embodiment 2.0 to 8.0 mm ² /s, or 2.0 to 7.0 mm ² /s, or 2.5 to 8.0 mm ² /s, or from 2.5 to 7.0 mm ² /s. Further, for example, when the lubricating oil composition is used for lubrication of an internal combustion engine, the kinematic viscosity at 100 ° C. of the lubricating oil composition is preferably 2.0 mm ² / s or more, more preferably 2.0 mm 2 / s or more, from the viewpoint of increasing wear resistance 4.0 mm ² /s or more, preferably 12.5 mm ² /s or less, more preferably 9.3 mm ² /s or less from the viewpoint of improving energy saving, and in one embodiment, 2.0 to 12 .5 mm ² /s, or 4.0-12.5 mm ² /s, or 2.0-9.3 mm ² /s, or 4.0-9.3 mm ² /s.

The kinematic viscosity at 40°C of the lubricating oil composition can be appropriately determined according to the use of the lubricating oil composition. For example, when the lubricating oil composition is used for lubricating a gear device such as a transmission (e.g., manual transmission, automatic transmission, continuously variable transmission, etc.), the kinematic viscosity at 40 ° C. of the lubricating oil composition is From the viewpoint of improving wear resistance, it is preferably 7.0 mm ² /s or more, more preferably 8.0 mm ² /s or more, and from the viewpoint of improving energy saving, it is preferably 50 mm ² /s or less, more preferably 45 mm ² . /s or less, in one embodiment 7.0 to 50 mm ² /s, or 7.0 to 45 mm ² /s, or 8.0 to 50 mm ² /s, or 8.0 to 45 mm ² /s could be. Further, for example, when the lubricating oil composition is used for lubrication of an internal combustion engine, the kinematic viscosity at 40° C. of the lubricating oil composition is preferably 4.0 mm ² /s or more, more preferably 4.0 mm 2 /s or more, from the viewpoint of increasing wear resistance. 6.0 mm ² /s or more, preferably 50 mm ² /s or less, more preferably 35 mm ² /s or less from the viewpoint of enhancing energy saving, and in one embodiment, 4.0 to 50 mm ² /s, or 6.0 to 50 mm ² /s, or 4.0 to 35 mm ² /s, or 6.0 to 35 mm ² /s.

The viscosity index of the lubricating oil composition is preferably 100 or more, more preferably 110 or more, and in one embodiment, 115 or more, or 120 or more, from the viewpoint of further improving energy saving and wear resistance.

(Application)
Since the lubricating oil composition of the present invention contains the component (B), the effect of reducing friction under gear lubricating conditions is enhanced. (For example, manual transmissions, automatic transmissions, continuously variable transmissions, speed reducers of electric vehicles, etc.) can be particularly preferably used for lubrication of mechanical devices including gear mechanisms.

Hereinafter, the present invention will be described more specifically based on examples and comparative examples. It should be noted that the following examples are intended to illustrate the present invention and are not intended to limit the present invention.

<Examples 1 to 42, and Comparative Examples 1 to 32>
Lubricating oil compositions of the present invention (Examples 1-42) and comparative lubricating oil compositions (Comparative Examples 1-32) were prepared, respectively, as shown in Tables 1-13. In the table, "mass%" in the item "base oil composition" means mass% based on the total amount of base oil (100% by mass), and "mass%" in other items refers to the total amount of the lubricating oil composition. It means % by mass based on the standard (100% by mass). In addition, "mass ppm" means mass ppm based on the total amount of the lubricating oil composition, and the notation "mass ppm/X" for element X means mass ppm based on the total amount of the composition as the amount of element X. do. Details of each component are as follows.

((A) lubricating base oil)
O-1: API Group III base oil (hydrocracked mineral oil base oil), kinematic viscosity (40°C): 12.7 mm ² /s, kinematic viscosity (100°C): 3.3 mm ² /s, viscosity index: 135, saturated content: 99.8% by mass, sulfur content: less than 1 mass ppm O-2: API Group V base oil (bis (2-ethylhexyl) azelate), kinematic viscosity (40 ° C.): 11.0 mm ² / s, kinematic viscosity (100° C.): 3.1 mm ² /s, viscosity index: 146
O-3: API Group IV base oil, kinematic viscosity (40°C): 63 mm ² /s, kinematic viscosity (100°C): 9.7 mm ² /s, viscosity index: 137
O-4: API Group IV base oil, kinematic viscosity (40°C): 396 mm ² /s, kinematic viscosity (100°C): 40 mm ² /s, viscosity index: 151
O-5: API Group V base oil (ester of mixed acid of caprylic acid and capric acid and trimethylolpropane), kinematic viscosity (40°C): 19.8 mm ² /s, kinematic viscosity (100°C): 4. 3 mm ² /s, viscosity index: 126

((B) Oil-based friction modifier)
B-1 (C8s-G3-E1): triglycerin monocaprylate (monoester of saturated monovalent fatty acid having 8 carbon atoms and glycerin trimer)
B-2 (C8s-G4-E1): tetraglycerin monocaprylate (monoester of saturated monovalent fatty acid having 8 carbon atoms and glycerin tetramer)
B-3 (C8s-G6-E1): hexaglycerin monocaprylate (monoester of saturated monovalent fatty acid having 8 carbon atoms and glycerin hexamer)
B'-4 (C12s-G2-E1): diglycerin monolaurate (monoester of saturated monovalent fatty acid having 12 carbon atoms and glycerin dimer)
B-5 (C12s-G3-E1): triglycerin monolaurate (monoester of saturated monovalent fatty acid with 12 carbon atoms and glycerin trimer)
B-6 (C12s-G4-E1): tetraglycerin monolaurate (monoester of saturated monovalent fatty acid with 12 carbon atoms and glycerin tetramer)
B-7 (C12s-G4-E1): hexaglycerin monolaurate (monoester of saturated monovalent fatty acid with 12 carbon atoms and glycerin hexamer)
B'-8 (C12s-G10-E1): decaglycerin monolaurate (monoester of saturated monovalent fatty acid with 12 carbon atoms and glycerin decamer)
B'-9 (C18s-G2-E1): diglycerin monostearate (monoester of saturated monovalent fatty acid having 18 carbon atoms and glycerin dimer)
B'-10 (C18u-G2-E1): diglycerin monooleate (monoester of unsaturated monovalent fatty acid having 18 carbon atoms and glycerin dimer)
B-11 (C18s-G4-E1): Tetraglycerin monostearate (monoester of saturated monovalent fatty acid having 18 carbon atoms and glycerin tetramer)
B-12 (C18u-G6-E1): hexaglycerin monooleate (monoester of unsaturated monovalent fatty acid having 18 carbon atoms and glycerin hexamer)
B-13 (C12s-G4-E2): Tetraglycerin dilaurate (diester of saturated monovalent fatty acid with 12 carbon atoms and glycerin tetramer)
B-14 (C12s-G4-E3): Tetraglycerin trilaurate (triester of saturated monovalent fatty acid having 12 carbon atoms and glycerin tetramer)
B-15 (C12s-G4-E4): Tetraglycerin tetralaurate (tetraester of saturated monovalent fatty acid having 12 carbon atoms and glycerin tetramer)
B'-16 (C18u-G1-E1): glycerin monooleate (monoester of unsaturated monovalent fatty acid having 18 carbon atoms and glycerin)
Here, the notation "Ci (s or u)-Gj-Ek" (i, j, and k are each integers of 1 or more) is an ester of a monovalent fatty acid with carbon number i and a glycerin j mer. , it means that k hydroxy groups of the glycerin j mer are esterified with fatty acids. Also, "s" after "Ci" means a saturated fatty acid, and "u" after "Ci" means an unsaturated fatty acid.

(other additives)
(C) Metallic detergent: calcium carbonate overbased calcium sulfonate, base value 300 mgKOH/g, Ca: 11.4% by mass
(D) Ashless dispersant: boric acid-modified polybutenylsuccinimide dispersant, N: 2.2% by mass, B: 0.5% by mass
(E) Phosphorus-containing antiwear agent: diphenyl hydrogen phosphite, P: 13.2% by mass
(F) Sulfur-containing extreme pressure agent: thiadiazole, S: 36% by mass
(G) Antioxidant: Phenolic antioxidant (H) Viscosity index improver: Polymethacrylate viscosity index improver, weight average molecular weight: 3.5×10 ⁴
Defoamer: Dimethyl silicone

(MTM test)
Each of the lubricating oil compositions was subjected to a ball-on-disk friction test using an MTM traction meter (manufactured by PCS Instruments) to measure the friction coefficient (μ) under conditions simulating gear lubrication. The measurement conditions are as follows.
Ball and disk: standard specimen (AISI52100 standard)
Oil temperature: 115°C
Load: 50N
Peripheral speed: 0.1m/s
Slip rate: 5%
The results are shown in Tables 1-13. For Examples 1 to 39, the friction coefficient reduction rate (%) relative to Comparative Example 1, for Example 40, the friction coefficient reduction rate (%) relative to Comparative Example 2, and for Example 41, the friction relative to Comparative Example 3. The coefficient reduction rate (%), the friction coefficient reduction rate (%) for Example 42 relative to Comparative Example 6, and the friction coefficient reduction rate (%) for Comparative Example 5 relative to Comparative Example 4 are shown in the table. described in

(Storage stability)
For each of the lubricating oil compositions, storage stability was evaluated on a three-grade scale from 1 to 3 by visually observing the state of the composition after the prepared composition was allowed to stand at 70° C. for 10 hours. The state of the composition corresponding to the 3-grade rating is as follows.
"3": The composition was transparent.
"2": Cloudiness was observed in the composition, but no precipitation was observed.
"1": Precipitation occurred in the composition.
The results are shown in Tables 1-13. A score of 2 or more in this test indicates that the composition has practical storage stability.

(Evaluation results)
The lubricating oil compositions of Examples 1 to 39 had sufficiently reduced coefficients of friction under conditions simulating gear lubrication with respect to the lubricating oil composition of Comparative Example 1 containing no oil-based friction modifier. was

The lubricating oil composition of Example 40 is a modified composition obtained by removing additives other than the component (B) from the composition of Example 2. The composition of Example 40 can be fairly compared with the composition of Comparative Example 2, which contains no additives other than component (B). The composition of Example 40 exhibited a significantly reduced coefficient of friction relative to the composition of Comparative Example 2, which did not contain component (B), under conditions simulating gear lubrication.

The lubricating oil composition of Example 41 was modified from the composition of Example 2 by changing the composition of (A) the base oil so that the kinematic viscosity of the entire base oil at 40° C. was 39.0 mm ² /s. It is a composition that For the composition of Example 41, a fair comparison is possible with the composition of Comparative Example 3, which has the same base oil composition. The composition of Example 41 exhibited a reduced coefficient of friction relative to the composition of Comparative Example 3, which did not contain component (B), under conditions simulating gear lubrication.

The lubricating oil composition of Example 42 is the composition of Example 2 modified by replacing the (A) base oil with an API Group V base oil. For the composition of Example 42, a fair comparison is possible with the composition of Comparative Example 6, which has the same base oil composition. The composition of Example 42 exhibited a significantly reduced coefficient of friction relative to the composition of Comparative Example 6, which did not contain component (B), under conditions simulating gear lubrication.

The lubricating oil composition of Comparative Example 5 further modified the composition of Example 41 by changing the composition of (A) the base oil so that the kinematic viscosity of the entire base oil at 40° C. was 42.0 mm ² /s. A modified composition. For the composition of Comparative Example 5, a fair comparison is possible with the composition of Comparative Example 4, which has the same base oil composition. The composition of Comparative Example 5 showed a reduced coefficient of friction compared to the composition of Comparative Example 4 containing no component (B) under conditions simulating gear lubrication, but the reduction rate was insufficient. Met.

In the lubricating oil composition of Comparative Example 7, friction modifier B'-16 (glycerin Modified composition replacing monooleate (C18u-G1-E1)). Although the composition of Comparative Example 7 showed a reduced friction coefficient compared to the composition of Comparative Example 1 containing no component (B) under conditions simulating lubrication of gears, the reduction rate was lower than that of Examples. inferior to 2.

The lubricating oil compositions of Comparative Examples 11-13, respectively, replaced all of the friction modifier B-5 (triglycerin monolaurate (C12s-G3-E1)) in the compositions of Examples 10-12 with the friction modifier B′-4 (diglycerin monolaurate (C12s-G2-E1)) replaced modified composition. The compositions of Comparative Examples 11 to 13 showed a reduced coefficient of friction compared to the composition of Comparative Example 1 that did not contain the component (B) under conditions simulating gear lubrication, but the reduction rate was They were inferior to Examples 10 to 12, respectively.

The lubricating oil compositions of Comparative Examples 17-19, respectively, replaced all of friction modifier B-7 (hexaglycerin monolaurate (C12s-G6-E1)) in the compositions of Examples 16-18 with friction modifier B'-8 (decaglycerin monolaurate (C12s-G10-E1)) is substituted for the modified composition. The compositions of Comparative Examples 17 to 19 exhibited a reduced friction coefficient compared to the composition of Comparative Example 1 containing no component (B) under conditions simulating gear lubrication, but the reduction rate was Each was inferior to Examples 16-18.

The lubricating oil compositions of Comparative Examples 20-22, respectively, replaced all of the friction modifier B-11 (tetraglycerin monostearate (C18s-G4-E1)) in the compositions of Examples 19-21 with the friction modifier B′-9 (diglycerin monostearate (C18s-G2-E1)) is replaced with a modified composition. The compositions of Comparative Examples 20 to 22 exhibited a reduced coefficient of friction compared to the composition of Comparative Example 1 containing no component (B) under conditions simulating gear lubrication, but the reduction rate was Each was inferior to Examples 19-21.

In the lubricating oil compositions of Comparative Examples 23-25, respectively, all of the friction modifier B-12 (hexaglycerin monooleate: C18u-G6-E1) in the compositions of Examples 22-24 was replaced with friction modifier B' -10 (diglycerin monooleate (C18u-G2-E1)). The compositions of Comparative Examples 23 to 25 exhibited a reduced friction coefficient compared to the composition of Comparative Example 1 that did not contain the component (B) under conditions simulating gear lubrication, but the reduction rate was Each was inferior to Examples 22-24.

The lubricating oil compositions of Comparative Examples 8 to 10, 14 to 16, and 26 to 32, in which the content of component (B) was excessive, were not practical in terms of storage stability.

From the above test results, it was shown that the lubricating oil composition of the present invention can exhibit an improved friction-reducing effect in gear lubrication.

Since the lubricating oil composition of the present invention exhibits an improved friction-reducing effect in lubricating metal surfaces susceptible to high loads such as gears, gear mechanisms, pistons, connecting-rod bearings, and the like, metal surfaces susceptible to high loads are provided. It can be suitably used for lubricating various mechanical devices, and can be particularly suitably used for lubricating transmissions and internal combustion engines.

Claims (6)

(A) a lubricating base oil comprising one or more mineral base oils or one or more synthetic base oils or a combination thereof and having a kinematic viscosity at 40° C. of 40 mm ² /s or less;
(B) a partial ester of one or more saturated or unsaturated monovalent fatty acids (b1) having 3 to 30 carbon atoms and one or more glycerol oligomers (b2) having a degree of polymerization of 3 to 6; A lubricating oil composition characterized in that it contains 0.05 to 2.5% by mass on a basis. The lubricating oil composition according to claim 1, wherein the fatty acid (b1) has 6 to 30 carbon atoms. (B′) contains or does not contain a partial ester of glycerin, a glycerin polymer other than the glycerin oligomer (b2), or a combination thereof with a fatty acid;
Claim 1 or 2, wherein the content of component (B') (unit: mass%) is 1/2 or less of the content of component (B) (unit: mass%) based on the total amount of the composition. The lubricating oil composition according to . Any one of claims 1 to 3, further comprising one or more additives selected from metallic detergents, ashless dispersants, phosphorus-containing antiwear agents, sulfur-containing extreme pressure agents, antioxidants, and viscosity index improvers. 1. The lubricating oil composition according to claim 1. The lubricating oil composition according to any one of claims 1 to 4, which has a kinematic viscosity at 40°C of 7.0 to 50 mm ² /s. The lubricating oil composition according to any one of claims 1 to 5, which is used for gear lubrication.