Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M169/00—Lubricating compositions characterised by containing as components a mixture of at least two types of ingredient selected from base-materials, thickeners or additives, covered by the preceding groups, each of these compounds being essential
  • C10M169/04—Mixtures of base-materials and additives
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M101/00—Lubricating compositions characterised by the base-material being a mineral or fatty oil
  • C10M101/02—Petroleum fractions
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M135/00—Lubricating compositions characterised by the additive being an organic non-macromolecular compound containing sulfur, selenium or tellurium
  • C10M135/32—Heterocyclic sulfur, selenium or tellurium compounds
  • C10M135/36—Heterocyclic sulfur, selenium or tellurium compounds the ring containing sulfur and carbon with nitrogen or oxygen
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M137/00—Lubricating compositions characterised by the additive being an organic non-macromolecular compound containing phosphorus
  • C10M137/02—Lubricating compositions characterised by the additive being an organic non-macromolecular compound containing phosphorus having no phosphorus-to-carbon bond
  • C10M137/04—Phosphate esters
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M137/00—Lubricating compositions characterised by the additive being an organic non-macromolecular compound containing phosphorus
  • C10M137/02—Lubricating compositions characterised by the additive being an organic non-macromolecular compound containing phosphorus having no phosphorus-to-carbon bond
  • C10M137/04—Phosphate esters
  • C10M137/10—Thio derivatives
  • C10M137/105—Thio derivatives not containing metal
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M141/00—Lubricating compositions characterised by the additive being a mixture of two or more compounds covered by more than one of the main groups C10M125/00 - C10M139/00, each of these compounds being essential
  • C10M141/10—Lubricating compositions characterised by the additive being a mixture of two or more compounds covered by more than one of the main groups C10M125/00 - C10M139/00, each of these compounds being essential at least one of them being an organic phosphorus-containing compound
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2203/00—Organic non-macromolecular hydrocarbon compounds and hydrocarbon fractions as ingredients in lubricant compositions
  • C10M2203/10—Petroleum or coal fractions, e.g. tars, solvents, bitumen
  • C10M2203/1006—Petroleum or coal fractions, e.g. tars, solvents, bitumen used as base material
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2215/00—Organic non-macromolecular compounds containing nitrogen as ingredients in lubricant Compositions
  • C10M2215/22—Heterocyclic nitrogen compounds
  • C10M2215/223—Five-membered rings containing nitrogen and carbon only
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2219/00—Organic non-macromolecular compounds containing sulfur, selenium or tellurium as ingredients in lubricant compositions
  • C10M2219/10—Heterocyclic compounds containing sulfur, selenium or tellurium compounds in the ring
  • C10M2219/104—Heterocyclic compounds containing sulfur, selenium or tellurium compounds in the ring containing sulfur and carbon with nitrogen or oxygen in the ring
  • C10M2219/106—Thiadiazoles
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2223/00—Organic non-macromolecular compounds containing phosphorus as ingredients in lubricant compositions
  • C10M2223/02—Organic non-macromolecular compounds containing phosphorus as ingredients in lubricant compositions having no phosphorus-to-carbon bonds
  • C10M2223/04—Phosphate esters
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2223/00—Organic non-macromolecular compounds containing phosphorus as ingredients in lubricant compositions
  • C10M2223/02—Organic non-macromolecular compounds containing phosphorus as ingredients in lubricant compositions having no phosphorus-to-carbon bonds
  • C10M2223/04—Phosphate esters
  • C10M2223/041—Triaryl phosphates
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2223/00—Organic non-macromolecular compounds containing phosphorus as ingredients in lubricant compositions
  • C10M2223/02—Organic non-macromolecular compounds containing phosphorus as ingredients in lubricant compositions having no phosphorus-to-carbon bonds
  • C10M2223/04—Phosphate esters
  • C10M2223/047—Thioderivatives not containing metallic elements
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2020/00—Specified physical or chemical properties or characteristics, i.e. function, of component of lubricating compositions
  • C10N2020/01—Physico-chemical properties
  • C10N2020/02—Viscosity; Viscosity index
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
  • C10N2030/02—Pour-point; Viscosity index
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
  • C10N2030/06—Oiliness; Film-strength; Anti-wear; Resistance to extreme pressure
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
  • C10N2030/10—Inhibition of oxidation, e.g. anti-oxidants
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
  • C10N2030/12—Inhibition of corrosion, e.g. anti-rust agents or anti-corrosives
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
  • C10N2030/40—Low content or no content compositions
  • C10N2030/42—Phosphor free or low phosphor content compositions
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
  • C10N2030/40—Low content or no content compositions
  • C10N2030/43—Sulfur free or low sulfur content compositions
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2040/00—Specified use or application for which the lubricating composition is intended
  • C10N2040/04—Oil-bath; Gear-boxes; Automatic transmissions; Traction drives

Definitions

• the present invention relates to a lubricating oil composition, a lubrication method using the lubricating oil composition, and a transmission equipped with the lubricating oil composition.
• Patent Document 1 lubricating oil compositions containing sulfur-based extreme pressure agents and phosphorus-based extreme pressure agents have been studied.
• the viscosity of the lubricating oil composition is lowered, fuel efficiency and cooling performance can be improved, but since the fluidity increases, it becomes difficult to form an oil film of the lubricating oil composition on the tooth surface. Further, due to the low viscosity of the lubricating oil composition, when the tooth surface is locally overheated, the layer thickness of the oil film of the lubricating oil composition may be reduced or broken. When the thickness of the oil film on the surface of the tooth surface is reduced or broken in this way, damage such as scuffing is likely to occur on the gears of the transmission. In this way, lowering the viscosity of the lubricating oil composition becomes a factor that causes damage to gears. In other words, it can be said that there is a trade-off relationship between lowering the viscosity of the lubricating oil composition and the gear protection property of the lubricating oil composition, which includes the property of suppressing scuffing.
• Patent Document 1 the use of a sulfur-based extreme pressure agent and a phosphorus-based extreme pressure agent in combination is considered in order to improve the scoring property (which has the same meaning as the scuffing resistance in the present application). There is.
• the lubricating oil composition of Patent Document 1 has a high kinematic viscosity at 100° C., does not meet the demand for lower viscosity, and cannot be said to have sufficient improvement in scoring properties.
• the present invention provides a lubricating oil composition that achieves both low viscosity and gear protection at a high level while also achieving superior copper corrosion prevention and oxidation stability, and a lubrication method using the lubricating oil composition. , and a transmission equipped with the lubricating oil composition.
• [1] Contains a base oil (A), a sulfur-based extreme pressure agent (B), and a phosphorus-based extreme pressure agent (C),
• the sulfur-based extreme pressure agent (B) is a thiadiazole having a branched organic group having 3 or more and 24 or less carbon atoms
• a lubricating oil composition wherein the phosphorus-based extreme pressure agent (C) is a phosphoric acid ester having an organic group containing a ring structure and having 6 or more and 24 or less carbon atoms.
• the base oil (A) contains mineral oil, and the content of the base oil (A) in the mineral oil based on the total amount (100 mass%) is 70.00 mass% or more, [1] or The lubricating oil composition according to [2].
• R B11 to R B32 each independently represent a branched organic group having 3 to 24 carbon atoms, and nB11 to nB32 each independently represent an integer from 1 to 4. .
• the organic group having 6 or more and 24 or less carbon atoms containing a ring structure of the phosphoric acid ester is an aryl group which may have a substituent.
• the described lubricating oil composition [6] The lubricating oil composition according to any one of [1] to [5], wherein the phosphoric acid ester is not an amine salt.
• the content of sulfur atoms in the lubricating oil composition is 0.01% by mass or more and 0.20% by mass or less, based on the total amount (100% by mass) of the lubricating oil composition, [1] The lubricating oil composition according to any one of ⁇ [8]. [10] The content of phosphorus atoms in the lubricating oil composition is 0.005% by mass or more and 0.100% by mass or less, based on the total amount (100% by mass) of the lubricating oil composition, [1] The lubricating oil composition according to any one of [9] to [9].
• a transmission comprising the lubricating oil composition according to any one of [1] to [13].
• a lubricating oil composition that achieves both low viscosity and gear protection at a high level while also achieving excellent copper corrosion prevention and oxidation stability, and a lubricating oil composition using the lubricating oil composition.
• a lubrication method and a transmission equipped with the lubricating oil composition can be provided.
• this embodiment an embodiment of the present invention (hereinafter sometimes referred to as “this embodiment”) will be described.
• the upper and lower limits of numerical ranges of "more than”, “less than”, and “ ⁇ ” can be arbitrarily combined, and the numerical values of Examples are used as the upper and lower limits. You can also do that.
• the lubricating oil composition of the present embodiment, the lubrication method using the lubricating oil composition, and the transmission equipped with the lubricating oil composition are only one embodiment of the present invention, and the present invention is limited thereto. It's not a thing.
• the lubricating oil composition of this embodiment contains a base oil (A), a sulfur-based extreme pressure agent (B), and a phosphorus-based extreme pressure agent (C), and the sulfur-based extreme pressure agent (B) is a thiadiazole having a branched organic group having 3 or more and 24 or less carbon atoms, and the phosphorus-based extreme pressure agent (C) is a phosphoric acid ester having an organic group having 6 or more and 24 or less carbon atoms containing a ring structure. It takes.
• the lubricating oil composition of the present embodiment contains, together with the base oil (A), a sulfur-based extreme pressure agent (B) having a specific structure and a phosphorus-based extreme pressure agent (C) having a specific structure. , it is possible to achieve both low viscosity and gear protection at a high level, and even better copper corrosion prevention and oxidation stability. In this way, by using the sulfur-based extreme pressure agent (B) with a specific structure and the phosphorus-based extreme pressure agent (C) with a specific structure, in addition to being effective as an extreme pressure agent, it is possible to create a lubricant with lower viscosity. Even if it is an oil composition, it exhibits high gear protection properties, and also makes it possible to achieve copper corrosion prevention properties and oxidation stability.
• lower viscosity means lowering the kinematic viscosity at 100° C. of the lubricating oil composition, and specifically, it is preferably 6.000 mm 2 /s or less.
• the kinematic viscosity at 100° C. can be determined by the method described in the Examples.
• the lubricating oil composition of Patent Document 1 has a large kinematic viscosity at 100°C, and in order to confirm that this has been improved in the lubricating oil composition of this embodiment, we focused on the kinematic viscosity at 100°C. .
• “Gear protection property” includes scuffing resistance, and means a property that prevents or suppresses damage to gears, etc. included in the gear.
• "Scuffing resistance” means a property that reduces local surface damage (scuffing) caused by solid phase fusion that occurs on sliding contact surfaces such as tooth surfaces of gears.
• “Gear protection” is a property that reduces local surface damage caused by solid-phase fusion that occurs on the tooth surface of a gear, for example, and this is measured by, for example, the shell four-ball wear test based on ASTM D4172-18 described in the examples. It can be evaluated by observing the wear scars caused by and the diameter of the wear scars. The occurrence of surface damage can be confirmed by observing wear marks, and the extent of the damage can also be confirmed from the size of the wear scar diameter. The smaller the wear scar diameter, the higher the "gear protection" can be evaluated.
• lubricating oil composition has a chemical effect on the object to be lubricated or whether the lubricating oil composition has a chemical influence from the object to be lubricated. This will serve as an indicator to evaluate whether or not it will be accepted.
• sulfur-based extreme pressure agents and phosphorus-based extreme pressure agents by adding sulfur-based extreme pressure agents and phosphorus-based extreme pressure agents, high gear protection can be obtained, but for example, corrosion of the copper surface of the object to be lubricated may occur, or The metal on the surface acts as a catalyst, causing decomposition of the sulfur-based extreme pressure agent and the phosphorus-based extreme pressure agent.
• the total content of the base oil (A), the sulfur-based extreme pressure agent (B), and the phosphorus-based extreme pressure agent (C) is the total amount of the lubricating oil composition. (100% by mass), in order to reduce viscosity and improve gear protection, the lower limit is preferably 60.00% by mass or more, more preferably 70.00% by mass or more, It is more preferably 80.00% by mass or more, even more preferably 85.00% by mass or more, even more preferably 88.00% by mass or more, and even more preferably 89.00% by mass or more. Even more preferred.
• the upper limit is preferably 100% by mass or less, more preferably 99.00% by mass or less, and 97.00% by mass or less. It is more preferable that the amount is at most 95.00% by mass, even more preferably at most 92.00% by mass.
• Gear protection is improved when the content of sulfur atoms in the lubricating oil composition is 0.01% by mass or more and 0.20% by mass or less, based on the total amount (100% by mass) of the lubricating oil composition. At the same time, it is preferable because excellent copper corrosion prevention properties and oxidation stability can be achieved.
• the lower limit is more preferably 0.02% by mass or more, and even more preferably 0.03% by mass or more.
• the upper limit is more preferably 0.15% by mass or less, even more preferably 0.10% by mass or less, even more preferably 0.09% by mass or less.
• Gear protection is improved when the content of phosphorus atoms in the lubricating oil composition is 0.005% by mass or more and 0.100% by mass or less, based on the total amount (100% by mass) of the lubricating oil composition. At the same time, it is preferable because excellent copper corrosion prevention properties and oxidation stability can be achieved.
• the lower limit is more preferably 0.010% by mass or more, and even more preferably 0.013% by mass or more.
• the upper limit is more preferably 0.080% by mass or less, even more preferably 0.050% by mass or less, even more preferably 0.035% by mass or less.
• the mass ratio (S/P ratio) of sulfur atoms to phosphorus atoms contained in the lubricating oil composition is 1.00 or more and 7.00 or less, gear protection properties are improved and copper corrosion prevention properties are particularly improved. This is preferable because it can improve the It is more preferable that the content of sulfur atoms and the content of phosphorus atoms are within the above range, and the S/P ratio is within the above range, but the lower limit of the S/P ratio is 1.10 or more. More preferably, it is 1.15 or more. The upper limit is more preferably 6.50 or less, even more preferably 6.00 or less, and even more preferably 5.40 or less.
• the content of sulfur atoms in the lubricating oil composition mainly depends on the content of the sulfur-based extreme pressure agent (B), and the content of phosphorus atoms in the lubricating oil composition mainly depends on the content of the sulfur-based extreme pressure agent (C). ) can be adjusted as appropriate depending on the content. Therefore, the S/P ratio can also be adjusted as appropriate depending on the contents of the sulfur-based extreme pressure agent (B) and the phosphorus-based extreme pressure agent (C).
• the upper limit of the kinematic viscosity at 100° C. of the lubricating oil composition is preferably 6.000 mm 2 /s or less, and 5.000 mm 2 /s, in order to achieve excellent fuel efficiency and oil film formation. s or less, more preferably 4.800 mm 2 /s or less, even more preferably 4.500 mm 2 /s or less, even more preferably 4.100 mm 2 /s or less.
• the lower limit is not particularly limited, but it is preferably 2.000 mm 2 /s or more, more preferably 3.000 mm 2 /s or more, and still more preferably 3.300 mm 2 /s or more.
• the speed is preferably 3.600 mm 2 /s or more, even more preferably 3.800 mm 2 /s or more.
• the upper limit of the kinematic viscosity at 40° C. of the lubricating oil composition is preferably 20.00 mm 2 /s or less, and 18.00 mm 2 /s, in order to achieve excellent fuel efficiency and oil film formation. s or less, more preferably 16.50 mm 2 /s or less, even more preferably 16.00 mm 2 /s or less, even more preferably 15.90 mm 2 /s or less.
• the lower limit is not particularly limited, but it is preferably 12.00 mm 2 /s or more, more preferably 13.00 mm 2 /s or more, and still more preferably 14.00 mm 2 /s or more.
• the speed is preferably 15.00 mm 2 /s or more, even more preferably 15.50 mm 2 /s or more.
• the upper limit of the viscosity index of the lubricating oil composition is preferably 180 or less, more preferably 175 or less, and 170 or less in order to achieve excellent fuel efficiency and oil film formation. is more preferably 167 or less, even more preferably 167 or less, the lower limit is not particularly limited, but is preferably 130 or more, more preferably 140 or more, still more preferably 145 or more, It is even more preferably 150 or more, and even more preferably 155 or more.
• the gear protection property was evaluated by observing the wear scars generated by the shell four-ball wear test and by the diameter of the wear scars, and the upper limit of the wear scar diameter is preferably 0.65 mm or less, and 0.65 mm or less. It is more preferably 63 mm or less, even more preferably 0.60 mm or less, even more preferably 0.58 mm or less, and even more preferably 0.55 mm or less. There is no particular limit to the lower limit, but it is generally about 0.30 mm.
• oxidation stability is evaluated by measuring the increase in acid value under the conditions of the ISOT test by measuring the increase in acid value before and after the test, but the upper limit for the increase in acid value is 0.20 or less. It is preferably at most 0.15, even more preferably at most 0.12, even more preferably at most 0.10. There is no particular restriction on the lower limit value, but generally, if it is about 0.01, there will be no problem in actual use.
• the upper limit of the copper elution amount is preferably 50 mass ppm or less, more preferably 45 mass ppm or less, and even more preferably 40 mass ppm or less, It is even more preferable that the content is 38 mass ppm or less.
• the lower limit There is no particular restriction on the lower limit, but generally, if it is about 5 mass ppm or more, there will be no problem in actual use.
• the base oil (A) used in this embodiment may be mineral oil, synthetic oil, or a mixed oil of mineral oil and synthetic oil.
• the mineral oil include atmospheric residual oil obtained by atmospheric distillation of crude oil such as paraffinic crude oil, intermediate base crude oil, naphthenic crude oil, etc.; distillate obtained by vacuum distillation of these atmospheric residual oils; Oil: Examples include mineral oils obtained by subjecting the distillate to one or more refining treatments such as solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, and hydrorefining.
• the mineral oil is preferably one that corresponds to either Group II or III in the API (American Petroleum Institute) base oil category. However, it is more preferred to use both mineral oils corresponding to Group II and Group III.
• Examples of the synthetic oil include polybutene, poly ⁇ -olefins such as ethylene- ⁇ -olefin copolymer, ⁇ -olefin homopolymer or copolymer; polyol ester, dibasic acid ester, phosphoric acid ester, etc.
• Various ester oils such as polyphenyl ether; polyglycols; alkylbenzenes; alkylnaphthalenes; obtained by isomerizing wax (GTL wax (Gas to Liquids WAX)) produced from natural gas by the Fischer-Tropsch method, etc.
• Examples include GTL base oil.
• one of the mineral oils and synthetic oils described above may be used alone, or a combination of multiple types of mineral oils may be used, or a combination of multiple types of synthetic oils may be used, A combination of mineral oil and synthetic oil may also be used.
• the base oil (A) preferably contains the mineral oil, and the content of the mineral oil based on the total amount of the base oil (A) (100% by mass) is preferably 70.00% by mass or more as a lower limit. , more preferably 80.00% by mass or more, still more preferably 90.00% by mass or more, even more preferably 95.00% by mass or more, and 98.00% by mass or more. is more preferred, and even more preferred is substantially only mineral oil.
• the lower limit of the kinematic viscosity at 40°C is preferably 8.000 mm 2 /s or more, more preferably 10.000 mm 2 /s or more, and 13 It is more preferably .000 mm 2 /s or more, and the upper limit is preferably 20.000 mm 2 /s or less, more preferably 17.500 mm 2 /s or less, even more preferably 14.500 mm 2 /s or less.
• the base oil (A) is preferably 6.000 mm 2 /s or less, more preferably 5.500 mm 2 /s or less, even more preferably 5.000 mm 2 /s or less.
• the lower limit is preferably 2.000 mm 2 /s or more, more preferably 2.500 mm 2 /s or more, and even more preferably 3.000 mm 2 /s or more.
• the lower limit of the content of the base oil (A) based on the total amount (100 mass%) of the lubricating oil composition is preferably 70.00 mass% or more, more preferably 80.00 mass% or more, and It is preferably 85.00% by mass or more, and the upper limit is preferably 99.00% by mass or less, more preferably 95.00% by mass or less, even more preferably 92.00% by mass or less.
• the content of the base oil (A) is within the above range, together with the sulfur-based extreme pressure agent (B) and the phosphorus-based extreme pressure agent (C) described below, it is possible to achieve both low viscosity and gear protection at a high level. However, it is preferable because it becomes easier to improve copper corrosion prevention properties and oxidation stability.
• the sulfur-based extreme pressure agent (B) used in this embodiment is required to be a thiadiazole having a branched organic group having 3 or more and 24 or less carbon atoms. This is preferable because it becomes easier to improve copper corrosion prevention and oxidation stability while achieving both low viscosity and gear protection at a high level.
• Thiadiazole with a branched organic group having 3 to 24 carbon atoms has substituents that are sterically crowded compared to thiadiazole with a straight chain organic group, making it difficult for metals with catalytic activity to approach the reaction point. Perhaps for this reason, thiadiazole is not easily affected and is thought to have excellent copper corrosion prevention properties and oxidation stability.
• the branched organic group is preferably a branched alkyl group or a branched alkenyl group, and more preferably a branched alkyl group.
• the branched organic group preferably has 5 to 20 carbon atoms, preferably 6 to 18 carbon atoms, more preferably 7 to 15 carbon atoms, even more preferably 8 to 13 carbon atoms, and has 9 to 12 carbon atoms. Even more preferred.
• a substituent represented by general formula (B0) is preferable.
• the branch in a branched alkyl group only means that the "alkyl group" has a branched chain.
• R B01 and R B02 each independently represent an alkyl group having 1 to 22 carbon atoms
• R B03 represents a hydrogen atom or an alkyl group having 1 to 21 carbon atoms
• nB01 is (Represents an integer from 0 to 20.)
• R B01 is preferably a linear alkyl group having 1 to 22 carbon atoms, more preferably a linear alkyl group having 1 to 8 carbon atoms, and is a methyl group, ethyl group, or n-propyl group. is more preferable, a methyl group or an ethyl group is even more preferable, and a methyl group is even more preferable.
• R B02 is preferably a linear alkyl group having 1 to 22 carbon atoms, more preferably a linear alkyl group having 3 to 12 carbon atoms, and preferably a linear alkyl group having 6 to 10 carbon atoms. is more preferred, and even more preferred is a straight-chain alkyl group having 6 to 9 carbon atoms.
• R B03 is preferably a hydrogen atom or a straight chain alkyl group having 1 to 22 carbon atoms, more preferably a hydrogen atom or a straight chain alkyl group having 1 to 8 carbon atoms, and is a methyl group, an ethyl group, or a straight chain alkyl group having 1 to 8 carbon atoms.
• -Propyl group is more preferable, methyl group or ethyl group is even more preferable, and methyl group is even more preferable.
• nB01 is preferably an integer of 0 to 8, more preferably an integer of 0 to 4, even more preferably an integer of 0 to 2, even more preferably 0 or 1, and even more preferably 0.
• the sulfur-based extreme pressure agent (B) is a compound selected from the compounds represented by general formulas (B1) to (B3), while achieving both low viscosity and gear protection at a high level, Further, it is preferable because it easily improves excellent copper corrosion prevention properties and oxidation stability, and the compound represented by the general formula (B1) is more preferable.
• R B11 to R B32 each independently represent a branched organic group having 3 to 24 carbon atoms, and nB11 to nB32 each independently represent an integer from 1 to 4. .
• R B11 to R B32 present in the same molecule may be the same branched organic group or different branched organic groups, but from the viewpoint of availability, it is preferable that they are the same branched organic group.
• the branched organic group is preferably a branched alkyl group or a branched alkenyl group, and more preferably a branched alkyl group.
• the branched organic group preferably has 5 to 20 carbon atoms, preferably 6 to 18 carbon atoms, more preferably 7 to 15 carbon atoms, even more preferably 8 to 13 carbon atoms, and has 9 to 12 carbon atoms. Even more preferred.
• the branched organic group is preferably a substituent represented by the above general formula (B0).
• Each of nB11 to nB32 is preferably independently an integer of 1 to 3, more preferably 1 or 2, and even more preferably 2.
• the content of sulfur atoms in the sulfur-based extreme pressure agent (B) is preferably 10.00% by mass or more, more preferably 20.00% by mass or more as a lower limit. , more preferably 30.00% by mass or more, and the upper limit is preferably 50.00% by mass or less, more preferably 40.00% by mass or less, still more preferably 36.00% by mass or less.
• the lower limit of the content of the sulfur-based extreme pressure agent (B) is preferably 0.01% by mass or more, based on the total amount (100% by mass) of the lubricating oil composition, in order to improve gear protection.
• the content is more preferably 0.03% by mass or more, even more preferably 0.05% by mass or more, and even more preferably 0.08% by mass or more.
• the upper limit is preferably 5.00% by mass or less, more preferably 3.00% by mass or less, even more preferably 2.00% by mass or less, and 1 It is even more preferably .00% by mass or less, even more preferably 0.50% by mass or less, and even more preferably 0.30% by mass or less.
• the content of sulfur atoms derived from the sulfur-based extreme pressure agent (B) is 0.01% by mass or more and 0.20% by mass or less based on the total amount (100% by mass) of the lubricating oil composition. This is preferred because it can achieve excellent copper corrosion prevention and oxidation stability while improving protection.
• the lower limit is more preferably 0.02% by mass or more, and even more preferably 0.03% by mass or more.
• the upper limit is more preferably 0.15% by mass or less, even more preferably 0.10% by mass or less, even more preferably 0.09% by mass or less.
• the phosphorus-based extreme pressure agent (C) used in this embodiment is required to be a phosphoric acid ester having an organic group containing a ring structure and having 6 to 24 carbon atoms. This is preferable because it becomes easier to improve copper corrosion prevention and oxidation stability while achieving both low viscosity and gear protection at a high level.
• the phosphoric esters preferably include phosphoric esters such as neutral phosphoric esters, acidic phosphoric esters, phosphorous esters, hydrogen phosphites, and amine salts of the phosphoric esters.
• phosphoric acid ester is not an amine salt; More preferably, it is a phosphoric acid ester.
• the phosphoric acid ester having an organic group having 6 to 24 carbon atoms and having a ring structure has substituents that are sterically crowded compared to the phosphoric acid ester having 6 to 24 carbon atoms that does not have a ring structure. Therefore, it is thought that the phosphoric acid ester is less affected and has excellent copper corrosion prevention properties and oxidation stability, probably because the metal with catalytic action is difficult to approach the reaction site.
• the carbon number of the organic group containing the ring structure is preferably 6 or more and 20 or less, more preferably 6 or more and 16 or less, even more preferably 6 or more and 14 or less, even more preferably 6 or more and 11 or less, and even more preferably 6 or more and 10 or less. Preferably, 9 is particularly preferable.
• the organic group containing a ring structure and having 6 to 24 carbon atoms in the phosphoric acid ester is an aryl group that may have a substituent. Since it is an aryl group, it contributes to steric hindrance, and since the aryl group itself has high chemical stability, it is thought that it exhibits excellent copper corrosion prevention properties and oxidation stability.
• the aryl group is preferably a phenyl group, a naphthalen-1-yl group or a naphthalen-2-yl group, and more preferably a phenyl group.
• the aryl group may be unsubstituted or may have a substituent.
• the substituent is preferably an organic group having 1 to 18 carbon atoms, more preferably a hydrocarbon group having 1 to 18 carbon atoms, even more preferably an alkyl group having 1 to 18 carbon atoms, and an alkyl group having 1 to 8 carbon atoms.
• the following alkyl groups are even more preferred, alkyl groups having 1 to 6 carbon atoms are even more preferred, and alkyl groups having 1 to 4 carbon atoms are even more preferred.
• the neutral phosphoric acid ester is preferably a compound represented by general formula (C1).
• R C11 to R C13 each independently represent a hydrocarbon group having 1 to 24 carbon atoms, and -CH 2 - in the alkyl group each independently represents -O- , -S-, -CO- or -CS-, each of nC11 to nC13 independently represents an integer of 0 to 5, but multiple R C11 to R C13 exist in the same molecule. In the case of .)
• R C11 to R C13 each independently represent a hydrocarbon group having 1 to 24 carbon atoms, and the hydrocarbon group is more preferably an alkyl group having 1 to 8 carbon atoms, and more preferably an alkyl group having 1 to 6 carbon atoms. An alkyl group having 1 or more and 4 or less carbon atoms is even more preferable.
• nC11 to nC13 are each independently preferably an integer of 0 to 3, preferably an integer of 0 to 2, and preferably 0 or 1.
• X C11 to X C13 are preferably -O-.
• the phosphorus content in the phosphorus-based extreme pressure agent (C) is preferably 1.00% by mass or more, more preferably 3.00% by mass or more, and still more preferably 6% by mass, in order to obtain better gear protection.
• the upper limit is preferably 15.00% by mass or less, more preferably 13.00% by mass or less, still more preferably 10.00% by mass or less.
• the lower limit of the content of the phosphorus-based extreme pressure agent (C) is preferably 0.01% by mass, based on the total amount (100% by mass) of the lubricating oil composition, in order to improve gear protection. 0.03% by mass is more preferred, 0.05% by mass is even more preferred, and even more preferably 0.10% by mass. Further, in order to exhibit excellent copper corrosion prevention properties and oxidation stability, the upper limit is preferably 3.00% by mass, more preferably 2.00% by mass, even more preferably 1.00% by mass, and 0.70% by mass. % is even more preferable, and 0.50% by mass is even more preferable.
• Gear protection is improved when the content of phosphorus atoms derived from the phosphorus-based extreme pressure agent (C) is 100 mass ppm or more and 500 mass ppm or less, based on the total amount (100 mass %) of the lubricating oil composition.
• C phosphorus-based extreme pressure agent
• the lower limit is more preferably 120 mass ppm or more, and even more preferably 140 mass ppm or more.
• the upper limit is more preferably 450 mass ppm or less, even more preferably 400 mass ppm or less, and even more preferably 350 mass ppm or less.
• the total content of the sulfur-based extreme pressure agent (B) and the phosphorus-based extreme pressure agent (C) is based on the total amount (100% by mass) of the lubricating oil composition, in order to improve gear protection.
• the lower limit is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.10% by mass or more, and even more preferably 0.20% by mass or more.
• the upper limit is preferably 3.00% by mass or less, more preferably 2.00% by mass or less, and even more preferably 1.00% by mass or less, It is even more preferably 0.80% by mass or less, and even more preferably 0.60% by mass or less.
• the lower limit is preferably 0.10 or more, more preferably 0.20 or more, and 0. .30 or more is more preferable.
• the upper limit is preferably 1.00 or less, more preferably 0.80 or less, even more preferably 0.70 or less, and 0.60 or less. is even more preferred.
• the lubricating oil composition may contain only the base oil (A), the sulfur-based extreme pressure agent (B), and the phosphorus-based extreme pressure agent (C), or may contain other additives described later. It may contain only the base oil (A), the sulfur-based extreme pressure agent (B), the phosphorus-based extreme pressure agent (C), and other additives to be described later.
• the lubricating oil composition of the present embodiment further includes, as other additives, other sulfur-based extreme pressure agents, other phosphorus-based extreme pressure agents, viscosity index improvers, antioxidants, fluidizing agents, etc. that can improve the quality of the product. It may contain at least one selected from a point depressant, a detergent, a friction modifier, an antifoaming agent, and a dispersant.
• the content of the other additive mixture is set to the total amount of the lubricating oil composition in order to achieve both low viscosity and gear protection at a high level, as well as superior copper corrosion prevention and oxidation stability.
• the lower limit is preferably 0.10% by mass or more, more preferably 1.00% by mass or more, even more preferably 3.00% by mass or more, and even more preferably 5.00% by mass or more. More preferably, it is 8.00% by mass or more.
• the upper limit is preferably 40.00% by mass or less, more preferably 30.00% by mass or less, even more preferably 20.00% by mass or less, even more preferably 15.00% by mass or less, and 12.00% by mass or less.
• the term "other additive mixture” does not mean only adding to the lubricating oil composition as a mixture of other additives, and also includes cases where only one type of other additive is used. When each other additive added to the lubricating oil composition is made into a mixture, it represents the content based on the total amount of the lubricating oil composition.
• the lubricating oil composition of the present embodiment may further contain another sulfur-based extreme pressure agent different from the sulfur-based extreme pressure agent (B), but from the viewpoint of making it easier to exhibit the effects of the present invention,
• the content of the other sulfur-based extreme pressure agent is preferably small.
• the content of the other sulfur-based extreme pressure agent is preferably less than 0.10% by mass, more preferably less than 0.05% by mass, and even more preferably less than 0.05% by mass, based on the total amount (100% by mass) of the lubricating oil composition. is less than 0.01% by mass, and more preferably contains no other sulfur-based extreme pressure agent.
• Examples of the other sulfur-based extreme pressure agent include thiadiazole that does not have a branched organic group having 3 to 24 carbon atoms in its structure, has a straight chain organic group, and has the general formula (B1 ) to (B3), R B11 to R B32 each independently represent a linear organic group having 1 to 24 carbon atoms, and nB11 to nB32 each independently represent an integer from 1 to 4.
• thiadiazole that does not have a branched organic group having 3 to 24 carbon atoms in its structure, has a straight chain organic group, and has the general formula (B1 ) to (B3)
• R B11 to R B32 each independently represent a linear organic group having 1 to 24 carbon atoms
• nB11 to nB32 each independently represent an integer from 1 to 4.
• the lubricating oil composition of the present embodiment may further contain the other phosphorus-based extreme pressure agent different from the phosphorus-based extreme pressure agent (C), but from the viewpoint of facilitating the effects of the present invention.
• the content of other phosphorus-based extreme pressure agents is preferably small.
• the content of the other phosphorus-based extreme pressure agent is preferably less than 0.47% by mass, more preferably less than 0.20% by mass, and even more preferably less than 0.20% by mass, based on the total amount (100% by mass) of the lubricating oil composition. is less than 0.10% by mass, more preferably less than 0.01% by mass, and even more preferably contains no other phosphorus-based extreme pressure agent.
• the other phosphorus-based extreme pressure agent is a phosphoric ester that does not have a ring structure in its structure, specifically a phosphoric ester that has 6 to 24 carbon atoms and does not have a ring structure in its structure. It is. More specifically, phosphoric ester compounds such as neutral phosphoric esters, acidic phosphoric esters, phosphites, hydrogen phosphites, etc. that do not have a ring structure in their structures, and the phosphoric ester compounds Examples include amine salts of. Among these, it is preferable that the content of acidic phosphoric acid ester or its amine salt that does not have a ring structure in its structure is small.
• the specific content of the acidic phosphoric acid ester or its amine salt that does not have a ring structure in its structure is the same as the specific content of the other phosphorus-based extreme pressure agents. Note that the other phosphorus-based extreme pressure agents can be used alone or in combination.
• Examples of the phosphoric acid esters having no ring structure in the structure include tributyl phosphate, ethyl dibutyl phosphate, trihexyl phosphate, tri(2-ethylhexyl) phosphate, tridecyl phosphate, trilauryl phosphate, trimyristyl phosphate, and trimyristyl phosphate.
• Examples include palmityl phosphate, tristearyl phosphate, trioleyl phosphate, and the like.
• acidic phosphoric acid esters having no ring structure in the structure include mono(di)ethyl acid phosphate, mono(di)n-propyl acid phosphate, mono(di)2-ethylhexyl acid phosphate, and mono(di)ethyl acid phosphate. ) butyl acid phosphate, mono(di)oleyl acid phosphate, mono(di)isodecyl acid phosphate, mono(di)lauryl acid phosphate, mono(di)stearyl acid phosphate, mono(di)isostearyl acid phosphate, etc. .
• Examples of the phosphite having no ring structure in the structure include triethyl phosphite, tributyl phosphite, tri(2-ethylhexyl) phosphite, tridecyl phosphite, trilauryl phosphite, and triisooctyl phosphite. phyto, tristearyl phosphite, and trioleyl phosphite.
• Examples of the hydrogen phosphite having no ring structure in the structure include mono(di)ethyl hydrogen phosphite, mono(di)-n-propyl hydrogen phosphite, and mono(di)-n- Butyl hydrogen phosphite, mono(di)-2-ethylhexyl hydrogen phosphite, mono(di)lauryl hydrogen phosphite, mono(di)oleyl hydrogen phosphite, mono(di)stearyl hydrogen phosphite, etc. Can be mentioned.
• amine salts of phosphoric ester compounds such as phosphoric esters having no ring structure in the structure, the acidic phosphoric esters, the phosphorous esters, and the hydrogen phosphite esters, these phosphoric acid esters, Preferable examples include amine salts formed from an ester compound and an amine.
• examples of amines used to form the amine salt include primary amines, secondary amines, tertiary amines, polyalkylene amines, etc.
• examples of primary amines, secondary amines, and tertiary amines include, Examples include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine, heptaethyleneoctamine, tetrapropylenepentamine, hexabutyleneheptamine, and the like.
• the lubricating oil composition of this embodiment further contains a viscosity index improver.
• a viscosity index improver By containing a viscosity index improver, even if the kinematic viscosity of the lubricating oil composition is lowered, a decrease in oil film formation at high temperatures can be suppressed, and gear protection properties are less likely to decrease at high temperatures, which is preferable. .
• viscosity index improver examples include polymers such as non-dispersed polymethacrylate, dispersed polymethacrylate, and styrenic copolymers (e.g., styrene-diene copolymer, styrene-isoprene copolymer, etc.). It will be done.
• the mass average molecular weight (Mw) of the viscosity index improver is appropriately set depending on its type, but from the viewpoint of viscosity characteristics, it is preferably 500 or more and 1,000,000 or less, more preferably 5,000 or more. 800,000 or less, more preferably 10,000 or more and 600,000 or less.
• Mw is preferably 5,000 or more and 300,000 or less, more preferably 10,000 or more and 100,000 or less, and even more preferably 20,000 or more and 50,000 or less.
• Mw can be measured, for example, by GPC (gel permeation chromatography) in terms of standard polystyrene.
• the lubricating oil composition of this embodiment further contains the antioxidant.
• an antioxidant By containing an antioxidant, excellent copper corrosion prevention properties and oxidation stability can be achieved.
• the antioxidant amine antioxidants and phenolic antioxidants are preferred.
• the amine antioxidants include dioctyldiphenylamine, phenyl- ⁇ -naphthylamine, diphenylamine, dinonyldiphenylamine, monobutylphenylmonoctylphenylamine, p-tert-octylphenyl-1-naphthylamine, 4,4'- Examples include bis( ⁇ , ⁇ -dimethylbenzyl)diphenylamine.
• the phenolic antioxidant preferably has a hindered phenol structure, such as 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,4,6-tri-tert-butylphenol, 2,6-di-tert-butyl-4-hydroxymethylphenol, 2,6-di-tert-butylphenol, 4,4'-methylenebis(2,6-di -tert-butylphenol), 4,4'-bis(2,6-di-tert-butylphenol), 4,4'-isopropylidenebis(2,6-di-tert-butylphenol), tridecyl-3-(3 , 5-di-tert-butyl-4-hydroxyphenyl) propionate, pentaerythritol tetrakis [3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octyl-3-
• the lubricating oil composition of this embodiment preferably further contains the pour point depressant.
• the pour point depressant include ethylene-vinyl acetate copolymers, condensates of chlorinated paraffins and naphthalene, condensates of chlorinated paraffins and phenols, polymethacrylates (PMA), polyalkylstyrenes, and the like. Polymethacrylate is preferred.
• the weight average molecular weight (Mw) of these polymers is preferably 50,000 or more and 150,000 or less. Mw can be measured, for example, by GPC (gel permeation chromatography) in terms of standard polystyrene.
• the lubricating oil composition of this embodiment further contains the above-mentioned detergent.
• the detergent include metal detergents such as salicylates such as sodium, calcium, and magnesium, sulfonates, and phenates, and calcium sulfonates are more preferred. These may be used alone or in combination of two or more.
• the lubricating oil composition of this embodiment preferably further contains the friction modifier.
• the friction modifier is preferably an ashless friction modifier.
• ashless compounds include amine friction modifiers, ester friction modifiers, amide friction modifiers, fatty acid friction modifiers, alcohol friction modifiers, ether friction modifiers, and urea friction modifiers. , hydrazide-based friction modifiers, etc., and preferably contains at least one selected from amine-based friction modifiers, ester-based friction modifiers, and amide-based friction modifiers, and amine-based friction modifiers are more preferred.
• the amine friction modifier amine friction modifiers that are normally used in the field of lubricating oil compositions can be used, but secondary amines are more preferred.
• the lubricating oil composition of this embodiment further contains the antifoaming agent.
• the antifoaming agent include silicone antifoaming agents, fluorine antifoaming agents such as fluorosilicone oil and fluoroalkyl ether, and polyacrylate antifoaming agents, with silicone antifoaming agents being preferred.
• the lubricating oil composition of this embodiment further contains the above-mentioned dispersant.
• the dispersant include boron-free succinimides, boron-containing succinimides, benzylamines, boron-containing benzylamines, succinic esters, fatty acids, or monovalent or divalent carboxylic acids represented by succinic acid.
• Examples include ashless dispersants such as acid amides, but boron-free succinimides or boron-containing succinimides are more preferred, polyalkenyl succinimides or boron-containing polyalkenyl succinimides are even more preferred, Even more preferred are polybutenyl succinimide or boron-containing polybutenyl succinimide.
• the polyalkenyl succinimide or boron-containing polyalkenyl succinimide preferably has a mass average molecular weight (Mw) of 500 or more and 2000 or less, more preferably 750 or more and 1500 or less, and 800 or more and 1200 or less. Even more preferred.
• the lubricating oil composition of this embodiment is capable of achieving both low viscosity and gear protection at a high level while also achieving superior copper corrosion prevention and oxidation stability.
• the lubricating oil composition of the embodiment can be used as a lubricating oil composition for drive system equipment such as shock absorbers, transmissions, and power steering, especially for transmissions, especially for transmissions such as gasoline vehicles, hybrid vehicles, and electric vehicles.
• it can be suitably used as a lubricating oil composition for transmissions for hybrid vehicles and electric vehicles.
• the lubrication method of this embodiment is a lubrication method using the above-mentioned lubricating oil composition
• the transmission of this embodiment is a transmission equipped with the above-mentioned lubricating oil composition.
• the lubrication method using the lubricating oil composition of this embodiment and the transmission equipped with the lubricating oil composition of this embodiment as a component can achieve both low viscosity and gear protection at a high level. Moreover, it also achieves excellent copper corrosion prevention properties and oxidation stability.
• other uses to which the lubricating oil composition of the present embodiment can be applied include, for example, internal combustion oil, hydraulic oil, turbine oil, compressor oil, lubricating oil for machine tools, cutting oil, gear oil, and fluid bearing oil. Compositions, rolling bearing oils and the like are also preferably mentioned. Further, according to the present embodiment, use of the above lubricating oil composition as a lubricating oil for a transmission is provided.
• the properties of the lubricating oil composition were measured by the following method.
• (1) Kinematic viscosity at 40°C (40°C kinematic viscosity), kinematic viscosity at 100°C (100°C kinematic viscosity), and viscosity index Measure the kinematic viscosity at 40°C and 100°C in accordance with JIS K2283:2000, The viscosity index was calculated.
• Viscosity index (VI) Calculated in accordance with ASTM D2270.
• Shell four-ball wear test (Shell wear) A test was conducted in accordance with ASTM D4172-18 under the conditions of 80° C., 1,200 rpm, 392 N, and 30 minutes, and the wear scar diameter (mm) was measured. The wear marks were observed under a microscope to confirm that surface damage had occurred, and the extent of the damage was further confirmed from the size of the wear scar diameter. A smaller wear scar diameter indicates better gear protection (wear resistance).
• Copper elution amount (Cu elution)
• ISOT test was conducted according to JIS K-2514-1 (2013) "Lubricating oil - Oxidation stability test”. That is, an iron-copper plate was placed in oil and stirred at 150°C, and the amount of copper eluted (mass ppm) after 72 hours was measured according to ASTM D4951. A smaller amount of copper elution indicates better copper corrosion prevention properties.
• (A), (B), and (C) represent base oil (A), sulfur-based extreme pressure agent (B), and phosphorus-based electrode based on the total amount (100% by mass) of the lubricating oil composition. It represents the content of pressure agent (C). A blank column indicates that the corresponding component is not included.
• S/P represents the mass ratio of sulfur atoms to phosphorus atoms contained in the lubricating oil composition.
• Thiadiazole (branched chain): Compound represented by formula (B-1) (having a branched organic group with 12 carbon atoms)
• R b21 to R b22 each independently represent a linear alkyl group having 6 to 10 carbon atoms, and mb21 to mb22 each independently represent an integer from 1 to 4.
• Benzotriazole mixture of compounds represented by general formula (BT)
• R BT1 represents a linear alkyl group having 1 to 4 carbon atoms or a hydrogen atom
• R BT2 to R BT3 each independently represent a linear alkyl group having 1 to 20 carbon atoms or a hydrogen atom. (represents an atom)
• Phosphorous compound (1) compound represented by formula (C-1) (having an organic group containing a ring structure with 6 or 10 carbon atoms)
• Phosphorus compound (2) Compound represented by formula (C-2) (having an organic group containing a ring structure with 9 carbon atoms)
• Phosphorous compound (3) Compound represented by formula (C-3) (having an organic group containing a ring structure with 7 carbon atoms)
• Acidic phosphoric acid extreme pressure agent dilauryl acid phosphate
• Other additive mixtures viscosity index improver, antioxidant, pour point depressant, detergent, friction modifier, antifoaming agent, dispersant, etc.
• Comparative Example 4 in which the sulfur-based extreme pressure agent (B) of Example 3 was replaced with benzotriazole, it was confirmed that although the copper corrosion prevention property and oxidation stability did not decrease, the gear protection property deteriorated significantly. It was done.
• Comparative Example 5 in which the phosphorus-based extreme pressure agent (C) was replaced with an acidic phosphoric acid extreme pressure agent, a uniform lubricating oil composition could be obtained, but precipitation subsequently occurred and the composition became non-uniform, resulting in poor physical property values. The lubricating oil composition could not be used as a practical lubricating oil composition.

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