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
  • C10M169/044—Mixtures of base-materials and additives the additives being a mixture of non-macromolecular and macromolecular compounds
• • 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
  • C10M145/00—Lubricating compositions characterised by the additive being a macromolecular compound containing oxygen
  • C10M145/02—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • C10M145/10—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing monomers having an unsaturated radical bound to a carboxyl radical, e.g. acrylate
  • C10M145/12—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing monomers having an unsaturated radical bound to a carboxyl radical, e.g. acrylate monocarboxylic
  • C10M145/14—Acrylate; Methacrylate
• • 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
  • C10M161/00—Lubricating compositions characterised by the additive being a mixture of a macromolecular compound and a non-macromolecular compound, each of these compounds being essential
• • 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
  • 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
  • C10M2209/00—Organic macromolecular compounds containing oxygen as ingredients in lubricant compositions
  • C10M2209/02—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • C10M2209/08—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds containing monomers having an unsaturated radical bound to a carboxyl radical, e.g. acrylate type
  • C10M2209/084—Acrylate; Methacrylate
• • 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
• • 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
  • 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
  • C10N2030/68—Shear stability
• • 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
  • C10N2040/042—Oil-bath; Gear-boxes; Automatic transmissions; Traction drives for automatic transmissions

Definitions

• the present invention relates to a lubricating oil composition suitable for an automatic transmission.
• a commercially available typical lubricating oil for an automatic transmission usually has a kinematic viscosity at 100 degrees C in a range from 7.0 mm 2 /s to 9.0 mm 2 /s.
• it is effective to reduce the stirring resistance of the lubricating oil, which requires lowering the viscosity of the lubricating oil.
• an automatic transmission oil with a kinematic viscosity at 100 degrees C in a range from 5.0 to 6.0 mm 2 /s see Patent Literature 1).
• a lubricating oil composition for a transmission that contains a specific lubricating base oil added with a specific polymethacrylate-based additive and has a kinematic viscosity at 100 degrees C in a range from 3.0 mm 2 /s to 8 mm 2 /s (see Patent Literature 2).
• a low-viscosity lubricating oil is less capable of forming an oil film when heated to a high temperature, which results in a reduced durability of transmission components (seizure resistance of gears). Further, a low-viscosity lubricating oil is likely to leak in a hydraulic oil controller of a transmission. Such oil leakage may lead to failure in transmission shift. In view of the above, in order to balance fuel-saving performance with component durability, it is important to ensure a high-temperature viscosity while keeping a low-temperature viscosity at a low level for a long duration of time. In the transmission oils as disclosed in Patent Literatures 1 and 2, fuel-saving performance and component durability are not sufficiently balanced.
• An object of invention is to provide a lubricating oil composition excellent in fuel-saving performance, shear stability and component durability.
• a lubricating oil composition excellent in fuel-saving performance, shear stability and component durability is suitably usable for an automatic transmission.
• a lubricating oil composition according to an exemplary embodiment of the invention (hereinafter also simply referred to as “the present composition”) is prepared by blending: a first base oil with a kinematic viscosity at 100 degrees C in a range from 1.5 mm 2 /s to 3.5 mm 2 /s; a second base oil with a kinematic viscosity at 100 degrees C in a range more than 3.5 mm 2 /s but not more than 100 mm 2 /s; polymethacrylate with a mass average molecular weight in a range from 1 ⁇ 10 4 to 4 ⁇ 10 4 ; and a sulfur compound.
• the lubricating oil composition has a predetermined kinematic viscosity at 100 degrees C and a predetermined viscosity index. Detailed description will be made below.
• the first base oil in the present composition has a kinematic viscosity at 100 degrees C in a range from 1.5 mm 2 /s to 3.5 mm 2 /s, preferably in a range from 1.5 mm 2 /s to 2.5 mm 2 /s.
• a kinematic viscosity at 100 degrees C is less than 1.5 mm 2 /s, seizure resistance is likely to be lowered irrespective of whether or not a viscosity of the second base oil is in a predetermined range (described later).
• the kinematic viscosity at 100 degrees C is more than 3.5 mm 2 /s, the fuel-saving performance is poor irrespective of whether or not the viscosity of the second base oil is in the predetermined range (described later).
• Such a base oil may be a mineral oil, a synthetic oil or a mixture thereof as long as the viscosity at 100 degrees C falls within the above range.
• the mineral oil is subject to no particular limitation but may be any appropriate one selected from among mineral oils usable as a base oil for a typical lubricating oil for an automobile transmission.
• the mineral oil may be a paraffin-based mineral oil, an intermediate-based mineral oil or a naphthene-based mineral oil.
• the synthetic oil is also subject to no particular limitation but may be polybutene, polyolefin, polyol ester, dibasic acid ester, phosphate, polyphenyl ether, polyglycol, alkylbenzene or alkylnaphthalene.
• polyolefin examples include an alpha-olefin homopolymer and an alpha-olefin copolymer.
• the second base oil in the present composition has a kinematic viscosity at 100 degrees C in a range more than 3.5 mm 2 /s but not more than 100 mm 2 /s, preferably in a range from 4 mm 2 /s to 8 mm 2 /s.
• a kinematic viscosity at 100 degrees C is not more than 3.5mm 2 /s, seizure resistance is likely to be lowered irrespective of whether or not the viscosity of the first base oil is in the above predetermined range.
• the kinematic viscosity at 100 degrees C is more than 100 mm 2 /s, the fuel-saving performance is poor irrespective of whether or not the viscosity of the first base oil is in the above predetermined range.
• the same oils as the mineral oils and the synthetic oils usable as the first base oil are usable as long as the second base oil has a viscosity in the above range.
• the blending amount A and the blending amount B preferably satisfy the following formula [1]. 0.6 ⁇ A / A + B ⁇ 1
• a / (A+B) is 0.6 or more, fuel-saving performance is sufficiently exhibited. Accordingly, A / (A+B) is preferably 0.65 or more. It should be noted that component durability cannot be sufficiently exhibited when the second base oil is not blended.
• the blending amount B of the second base oil is preferably 5 mass% or more based on the total composition amount, more preferably 10 mass% or more.
• the blending amount of the second base oil is 5 mass% or more, the durability of bearings and gear components is improved.
• the polymethacrylate in the present composition serves as a viscosity index improver and thus should have a mass average molecular weight in a range from 1 ⁇ 10 4 to 4 ⁇ 10 4 .
• the mass average molecular weight of the polymethacrylate is less than 1 ⁇ 10 4 , the polymethacrylate cannot sufficiently serve as a viscosity index improver.
• the mass average molecular weight of the polymethacrylate is more than 4 ⁇ 10 4 , the shear stability is poor.
• Examples of the polymethacrylate are a non-dispersed polymethacrylate and a dispersed polymethacrylate.
• the non-dispersed polymethacrylate and the dispersed polymethacrylate may be used alone or in combination.
• a blending amount of the polymethacrylate is preferably in a range from 1 mass% to 16 mass% based on the total composition amount, more preferably in a range from 7 mass% to 13 mass%. When the blending amount of the polymethacrylate is 1 mass% or more, the polymethacrylate is sufficiently effective for improving the viscosity index. When the blending amount is 16 mass% or less, the fuel-saving performance is improved.
• the sulfur compound in the present composition contributes to the durability of a component such as a gear.
• the sulfur content of the sulfur compound is preferably 20 mass% or more based on the sulfur compound in terms of improvement in durability.
• a thiadiazole compound is favorably usable as the sulfur compound.
• thiadiazole compound examples are a 2,5-bis(n-hexyldithio)-1,3,4-thiadiazole, 2,5-bis(n-octyldithio)-1,3,4-thiadiazole, 2,5-bis(n-nonyldithio)-1,3,4-thiadiazole, 2,5-bis[(1,1,3,3-tetramethylbutyl)dithio]-1,3,4-thiadiazole, 3,5-bis(n-hexyldithio)-1,2,4-thiadiazole, 3,6-bis(n-octyldithio)-1,2,4-thiadiazole, 3,5-bis(n-nonyldithio)-1,2,4-thiadiazole, 3,5-bis[(1,1,3,3-tetramethylbutyl)dithio]-1,2,4-thiadiazole, 4,5-bis(n-octyldithio)
• a mono/diolefin sulfide, dihydrocarbyl mono/disulfide, dithiocarbamate compound, ester compound with a disulfide structure, and the like are also favorably usable in addition to the thiadiazole compound.
• a favorable blending amount of the sulfur compound is 0.03 mass% or more based on the total composition amount, preferably 0.05 mass% or more. It should be noted that the blending amount is preferably not more than 0.5 mass% in terms of oxidation stability.
• the present composition is prepared by blending the above base oils with an additive and has a kinematic viscosity at 100 degrees C in a range from 5mm 2 /s to 6 mm 2 /s.
• a kinematic viscosity at 100 degrees C is less than 5 mm 2 /s, the component durability is poor.
• the kinematic viscosity at 100 degrees C is more than 6 mm 2 /s, the fuel-saving performance is poor.
• the present composition has a viscosity index of 200 or more. Therefore, a decrease in a high-temperature viscosity of the present composition can be reduced, so that the present composition is excellent in component durability.
• the present composition which is prepared by blending the predetermined mixed base oil as described above with the predetermined additive, keeps an initial viscosity even when heated to a high temperature. Further, the viscosity of the component is kept at an appropriate level even after long-duration shearing, so that the present composition can exhibit fuel-saving performance and component durability. In other words, the present composition does not cause problems such as deterioration of the component durability (e.g., seizure of a gear) resulting from a decrease in the high-temperature viscosity and leakage of a hydraulic pressure in a hydraulic pressure controller. Therefore, the present composition is suitably usable as a lubricating oil especially for an automatic transmission.
• the present composition may be blended with a variety of additives as listed below as long as the effects of the invention can be exhibited.
• additives are a detergent dispersant, an antiwear agent, a friction modifier and an antioxidant.
• an ashless dispersant and a metallic dispersant are usable.
• ashless dispersant examples include a succinimide compound, boron imide compound, Mannich dispersant and acid amide compound. One of these examples may be used alone or, alternatively, two or more thereof may be used in combination.
• a blending amount of the ashless dispersant is subject to no particular limitation but is preferably in a range from 0.1 mass% to 20 mass% based on the total composition amount.
• Examples of the metallic dispersant are alkali metal sulfonate, alkali metal phenate, alkali metal salicylate, alkali metal naphthenate, alkaline earth metal sulfonate, alkaline earth metal phenate, alkaline earth metal salicylate and alkaline earth metal naphthenate.
• One of these examples may be used alone or, alternatively, two or more thereof may be used in combination.
• a blending amount of the metallic dispersant is subject to no particular limitation but is preferably in a range from 0.1 mass% to 10 mass% based on the total composition amount.
• the antiwear agent is exemplified by a sulfur-based compound or a phosphorus-based compound.
• sulfur-based compound examples include olefin sulfide, sulfurized fat and oil, ester sulfide, thiocarbonates, dithiocarbamates and polysulfides.
• phosphorus-based compound examples include phosphites, phosphates, phosphonates, and amine salts or metal salts of these esters. One of these examples may be used alone or, alternatively, two or more thereof may be used in combination.
• a blending amount of the antiwear agent is preferably in a range from 0.1 mass% to 20 mass% based on the total composition amount.
• the friction modifier is exemplified by fatty acid ester, fatty acid amide, fatty acid, aliphatic alcohol, aliphatic amine or aliphatic ether.
• a substance having at least one alkyl group or alkenyl group having 6 to 30 carbon atoms in a molecule is usable.
• oleic acid and oleylamine are favorably usable.
• One of these examples may be used alone or, alternatively, two or more thereof may be used in combination.
• a blending amount of the friction modifier is preferably in a range from 0.01 mass% to 2 mass% based on the total composition amount, more preferably in a range from 0.01 mass% to 1 mass%.
• antioxidants examples include amine antioxidants such as alkylated diphenylamine, phenyl-alpha-naphthylamine and alkylated-alpha-naphthylamine and phenol antioxidants such as 2,6-di-t-butyl-4-methylphenol and 4,4 -methylenebis(2,6-di-t-butylphenol).
• a blending amount of the antioxidant is preferably in a range from 0.05 mass% to 25 mass% based on the total composition amount.
• Sample oils were prepared according to compositions shown below and were measured in kinematic viscosity (40 degrees C and 100 degrees C), viscosity index, shear stability and gear durability by a method as described below.
• a kinematic viscosity at 100 degrees C was measured with a KRL shear tester after the elapse of 96 hours since shearing was started.
• a practical target value was 4.8 mm 2 /s or more.
• a load stage was gradually set higher and higher under such conditions that a gear speed along a pitch circle was 8.3 m/s and the temperature of a hydraulic oil was 90 degrees C to find out a level of the load stage at the time when scuffing with a width of 20 mm or more was caused.
• the sample oils of Examples 1 to 5 each have a low viscosity and a high viscosity index and are excellent in shear stability and gear durability.
• the lubricating oil composition according to the exemplary embodiment exhibits excellent performance especially when used for an automatic transmission.

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• Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Lubricants (AREA)

Applications Claiming Priority (2)

Publications (2)

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• 2011
  • 2011-12-06 JP JP2011267086A patent/JP5965139B2/ja not_active Expired - Fee Related
• 2012
  • 2012-11-29 WO PCT/JP2012/080893 patent/WO2013084783A1/fr active Application Filing
  • 2012-11-29 EP EP12855599.2A patent/EP2789680A4/fr not_active Withdrawn
  • 2012-11-29 CN CN201280059870.5A patent/CN103987823A/zh active Pending
  • 2012-11-29 US US14/362,728 patent/US20140364350A1/en not_active Abandoned
• 2016
  • 2016-03-03 US US15/060,084 patent/US20160186091A1/en not_active Abandoned

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