EP3492568A1 - Lubricant composition - Google Patents
Lubricant composition Download PDFInfo
- Publication number
- EP3492568A1 EP3492568A1 EP17834561.7A EP17834561A EP3492568A1 EP 3492568 A1 EP3492568 A1 EP 3492568A1 EP 17834561 A EP17834561 A EP 17834561A EP 3492568 A1 EP3492568 A1 EP 3492568A1
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- EP
- European Patent Office
- Prior art keywords
- weight
- lubricant composition
- ppm
- salicylate
- magnesium
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- 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
- C10M129/00—Lubricating compositions characterised by the additive being an organic non-macromolecular compound containing oxygen
- C10M129/02—Lubricating compositions characterised by the additive being an organic non-macromolecular compound containing oxygen having a carbon chain of less than 30 atoms
- C10M129/26—Carboxylic acids; Salts thereof
- C10M129/48—Carboxylic acids; Salts thereof having carboxyl groups bound to a carbon atom of a six-membered aromatic ring
- C10M129/54—Carboxylic acids; Salts thereof having carboxyl groups bound to a carbon atom of a six-membered aromatic ring containing hydroxy groups
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- 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
- C10M125/00—Lubricating compositions characterised by the additive being an inorganic material
- C10M125/22—Compounds containing sulfur, selenium or tellurium
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- 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
- C10M163/00—Lubricating compositions characterised by the additive being a mixture of a compound of unknown or incompletely defined constitution and a non-macromolecular compound, each of these compounds being essential
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- 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
- C10M135/12—Thio-acids; Thiocyanates; Derivatives thereof
- C10M135/14—Thio-acids; Thiocyanates; Derivatives thereof having a carbon-to-sulfur double bond
- C10M135/18—Thio-acids; Thiocyanates; Derivatives thereof having a carbon-to-sulfur double bond thiocarbamic type, e.g. containing the groups
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- 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
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- 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
- C10M2205/00—Organic macromolecular hydrocarbon compounds or fractions, whether or not modified by oxidation as ingredients in lubricant compositions
- C10M2205/17—Fisher Tropsch reaction products
- C10M2205/173—Fisher Tropsch reaction products used as base material
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- 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
- C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
- C10M2207/02—Hydroxy compounds
- C10M2207/023—Hydroxy compounds having hydroxy groups bound to carbon atoms of six-membered aromatic rings
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- 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
- C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
- C10M2207/02—Hydroxy compounds
- C10M2207/023—Hydroxy compounds having hydroxy groups bound to carbon atoms of six-membered aromatic rings
- C10M2207/026—Hydroxy compounds having hydroxy groups bound to carbon atoms of six-membered aromatic rings with tertiary alkyl groups
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- 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
- C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
- C10M2207/26—Overbased carboxylic acid salts
- C10M2207/262—Overbased carboxylic acid salts derived from hydroxy substituted aromatic acids, e.g. salicylates
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- 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
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- 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
- C10M2215/28—Amides; Imides
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- 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
- C10M2219/04—Organic non-macromolecular compounds containing sulfur, selenium or tellurium as ingredients in lubricant compositions containing sulfur-to-oxygen bonds, i.e. sulfones, sulfoxides
- C10M2219/046—Overbasedsulfonic acid salts
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- 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
- C10M2219/06—Thio-acids; Thiocyanates; Derivatives thereof
- C10M2219/062—Thio-acids; Thiocyanates; Derivatives thereof having carbon-to-sulfur double bonds
- C10M2219/066—Thiocarbamic type compounds
- C10M2219/068—Thiocarbamate metal salts
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- 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
- C10M2223/045—Metal containing thio derivatives
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- 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
- C10N2010/00—Metal present as such or in compounds
- C10N2010/04—Groups 2 or 12
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- 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
- C10N2010/00—Metal present as such or in compounds
- C10N2010/12—Groups 6 or 16
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- 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
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- 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
- C10N2030/04—Detergent property or dispersant property
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- 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
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- 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
- C10N2030/52—Base number [TBN]
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- 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
- C10N2040/25—Internal-combustion engines
Definitions
- the present invention relates to a lubricant composition. More specifically, the present invention relates to a lubricant composition for an internal combustion engine, particularly a lubricant composition for a gasoline engine.
- Lubricant compositions are widely used in the automotive field for internal combustion engines, automatic transmissions, gear oils and the like. In recent years, such lubricant compositions are demanded to have a reduced viscosity for improving the fuel efficiency; however, since a reduction in viscosity leads to a reduced oil film thickness, friction cannot be sufficiently reduced. Accordingly, molybdenum dithiocarbamate (MoDTC) capable of reducing friction by yielding molybdenum disulfide under boundary lubrication conditions has been conventionally used. In such cases, MoDTC is usually used in combination with a calcium-based detergent (e.g., Japanese Unexamined Patent Publication (Kokai) No. 2013-199594 (PTL 1)). However, this combination has a limitation in reducing friction and thus cannot sufficiently improve the fuel efficiency.
- MoDTC molybdenum dithiocarbamate
- a magnesium-based detergent as a detergent (e.g., Japanese Unexamined Patent Publication (Kokai) No. 2011-184566 (PTL 2) and Japanese Unexamined Patent Publication (Kokai) No. 2006-328265 (PTL 3)).
- the use of a magnesium-based detergent can reduce friction more than the use of a calcium-based detergent; however, it has a problem of being likely to cause wear.
- An object of the present invention is to provide a lubricant composition capable of reducing friction while ensuring anti-wear properties even at a reduced viscosity, preferably a lubricant composition used in an internal combustion engine, more preferably a lubricant composition used in a supercharged gasoline engine.
- the present inventors intensively studied to discover that the above-described object can be achieved by adding a specific amount of at least one metal salicylate selected from calcium salicylate and magnesium salicylate and a specific amount of a molybdenum-based friction modifier to a lubricant base oil.
- the present invention is a lubricant composition containing: a lubricant base oil; (A1) a metal salicylate; and (B) a molybdenum-based friction modifier, wherein the amount of component (B) is in a range of 500 to 1,500 ppm by weight in terms of a concentration [B] in ppm by weight of molybdenum in the lubricant composition, component (A1) is any one of calcium salicylate, magnesium salicylate, and a combination thereof, the amount of calcium salicylate is 0 to 1,800 ppm by weight in terms of a concentration [Ca] in ppm by weight of calcium derived from calcium salicylate in the lubricant composition, the amount of magnesium salicylate is 0 to 1,800 ppm by weight in terms of a concentration [Mg] in ppm by weight of magnesium derived from magnesium salicylate in the lubricant composition, and a total of [Ca] and [Mg] is in a range of 200 to
- the lubricant composition further includes at least one of following characteristic features (1) to (10):
- the present invention also relates to a method of reducing friction while maintaining low-wear properties by using the above-described lubricant composition or the lubricant composition according to any one of embodiments (1) to (10).
- the lubricant composition of the present invention is capable of reducing friction while ensuring anti-wear properties even at a reduced viscosity, and can thus be suitably used as a lubricant composition for internal combustion engines, particularly as a lubricant composition for supercharged gasoline engines.
- the lubricant base oil is not particularly restricted.
- the lubricant base oil may be any one of mineral oils and synthetic oils, and these oils can be used singly or as a mixture.
- mineral oils examples include oils obtained by distilling an atmospheric residue, which is generated by atmospheric distillation of crude oil, under reduced pressure and refining the resulting lubricant fraction by one or more treatments, such as solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, and hydrorefining; wax-isomerized mineral oils; GTL (Gas-to-Liquid) base oils; ATL (Asphalt-to-Liquid) base oils; vegetable oil-derived base oils; and mixed base oils thereof.
- Examples of the synthetic oils include polybutenes and hydrogenated products thereof; poly- ⁇ -olefins, such as 1-octene oligomer and 1-decene oligomer, and hydrogenated products thereof; monoesters, such as 2-ethylhexyl laurate, 2-ethylhexyl palmitate, and 2-ethylhexyl stearate; diesters, such as ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, and di-2-ethylhexyl sebacate; polyol esters, such as neopentyl glycol di-2-ethylhexanoate, neopentyl glycol di- n -octanoate, neopentyl glycol di- n -decanoate, trimethylolpropane tri
- the kinematic viscosity (mm 2 /s) at 100°C of the lubricant base oil is not particularly restricted; however, it is preferably 2 to 15 mm 2 /s, more preferably 3 to 10 mm 2 /s, still more preferably 3 to 8 mm 2 /s, most preferably 3 to 6 mm 2 /s.
- a lubricant composition which not only sufficiently forms an oil film and provides excellent lubricity but also has less evaporation loss can be obtained.
- the viscosity index (VI) of the lubricant base oil is not particularly restricted; however, it is preferably 100 or higher, more preferably 120 or higher, most preferably 130 or higher. By this, the viscosity at low temperatures can be reduced while securing an oil film at high temperatures.
- the lubricant composition of the present invention is characterized by comprising, as a metallic detergent (A), a metal salicylate (A1) which is calcium salicylate, magnesium salicylate or a combination thereof in the below-described specific range of amount.
- the lubricant composition of the present invention may further comprise other metallic detergent than calcium salicylate and magnesium salicylate as the metallic detergent (A), and it is appropriate that the weight ratio of component (A1) based on the total weight of the metallic detergent (A) be in a range of 5 to 100% by weight, preferably 10 to 100% by weight, more preferably 15 to 100% by weight, particularly preferably 20 to 100% by weight, most preferably 50 to 100% by weight, in terms of a ratio of [Ca] and [Mg] based on a total concentration [A] in ppm by weight of metals derived from the metallic detergent in the lubricant composition, wherein [Ca] is a concentration in ppm by weight of calcium derived from calcium salicylate in the lubricant composition, and [M
- the lubricant composition can ensure high-temperature detergency and rust inhibition that are required as a lubricant.
- the lubricant composition can reduce friction and, therefore, can reduce torque. This is advantageous particularly from the standpoint of fuel efficiency characteristics.
- the amount of component (A1) in the lubricant composition of the present invention is 0 to 1,800 ppm by weight, preferably 0 to 1,600 ppm by weight, in terms of the concentration [Ca] in ppm by weight of calcium in the lubricant composition;
- the amount of magnesium salicylate is 0 to 1,800 ppm by weight, preferably 0 to 1,600 ppm by weight, in terms of the concentration [Mg] in ppm by weight of magnesium in the lubricant composition;
- the value of [Ca] + [Mg] is in a range of 200 to 3,000 ppm by weight, preferably 300 to 2,500 ppm by weight, more preferably 400 to 2,000 ppm by weight.
- At least one selected from magnesium salicylate and calcium salicylate is indispensable as the metal salicylate. Only a single kind of these metal salicylates may be used, or two or more kinds thereof may be used in combination. A combination of magnesium salicylate and calcium salicylate, or magnesium salicylate alone is preferable, and magnesium salicylate is more preferable.
- component (A1) is magnesium salicylate alone, it is appropriate that the content thereof in terms of the concentration [Mg] in ppm by weight of magnesium derived from magnesium salicylate in the lubricant composition be in a range of 200 to 1,800 ppm by weight, preferably 250 to 1,500 ppm by weight, more preferably 300 to 1,200 ppm by weight, most preferably 400 to 1,000 ppm.
- component (A1) is calcium salicylate alone, it is appropriate that the content thereof in terms of the concentration [Ca] in ppm by weight of calcium derived from calcium salicylate in the lubricant composition be in a range of 200 to 1,800 ppm by weight, preferably 300 to 1,600 ppm by weight, more preferably 500 to 1,400 ppm by weight.
- component (A1) is a combination of magnesium salicylate and calcium salicylate
- a total of [Ca] and [Mg] satisfy a range of 200 to 3,000 ppm by weight, preferably 300 to 2,500 ppm by weight, more preferably 400 to 2,000 ppm by weight.
- [Mg] be in a range of 100 to 1,600 ppm by weight, preferably 150 to 1,400 ppm by weight, more preferably 200 to 1,200 ppm by weight, most preferably 300 to 1,000 ppm
- [Ca] be in a range of 100 to 1,600 ppm by weight, preferably 300 to 1,500 ppm by weight, more preferably 500 to 1,400 ppm by weight.
- the magnesium content in magnesium salicylate and the calcium content in calcium salicylate are each preferably 0.5 to 20% by weight, more preferably 1 to 16% by weight, most preferably 2 to 14% by weight.
- the amount of component (A1) to be added is adjusted such that magnesium and calcium are incorporated into the lubricant composition in the above-described respective ranges of amount.
- the metal salicylate (A1) is preferably an overbased metal salicylate, more preferably a combination of magnesium salicylate and calcium salicylate, especially preferably overbased magnesium salicylate.
- an overbased metal salicylate more preferably a combination of magnesium salicylate and calcium salicylate, especially preferably overbased magnesium salicylate.
- a neutral magnesium- or calcium-based detergent may be mixed therewith.
- a neutral calcium-based detergent may be used in combination.
- the total base number of the metal salicylate (A1) is not restricted; however, it is preferably 20 to 600 mg KOH/g, more preferably 50 to 500 mg KOH/g, most preferably 100 to 450 mg KOH/g. By this, acid neutralization performance, high-temperature detergency and rust inhibition that are required for a lubricant can be ensured.
- the base number of the mixture is preferably in the above-described range.
- the amount of component (A1) in the lubricant composition satisfies following equation (2): A 1 / B ⁇ 4.5
- [A1] represents a total concentration (i.e. [Ca] + [Mg]) in ppm by weight of magnesium and calcium that are derived from the magnesium salicylate and calcium salicylate (A1) in the lubricant composition, and [B] is as described above.
- the value of [A1]/[B] is preferably less than 3.0, more preferably less than 2, still more preferably less than 1.8, particularly preferably less than 1.5. When the value of [A1]/[B] is greater than the above-described upper limit, the torque-reducing effect may be low.
- the lower limit value of [A1]/[B] is preferably 0.1, more preferably 0.2, still more preferably 0.3.
- the lubricant composition of the present invention comprises only magnesium salicylate as the metal salicylate (A1), or a combination of magnesium salicylate and calcium salicylate as component (A1).
- the lubricant composition of the present invention may further contain (A2) a metallic detergent other than the calcium salicylate and magnesium salicylate (A1) as the metallic detergent (A).
- the weight ratio of component (A1) based on the total weight of the metallic detergent (A) be 5 to 100% by weight, preferably 10 to 100% by weight, more preferably 15 to 100% by weight, particularly preferably 20 to 100% by weight, most preferably 50 to 100% by weight, in terms the ratio of [Ca] and [Mg] based on the total concentration [A] in ppm by weight of metals derived from the metallic detergent in the lubricant composition.
- the percentage (% by weight) of magnesium salicylate based on the total weight of the metallic detergent (A) be 5 to 100% by weight, preferably 10 to 80% by weight, more preferably 10 to 60% by weight, particularly preferably 10 to 40% by weight, in terms the percentage of [Mg] based on the total concentration [A] in ppm by weight of metals derived from the metallic detergent in the lubricant composition.
- the lubricant composition of the present invention comprises only magnesium salicylate, or only a combination of magnesium salicylate and calcium salicylate, as the metallic detergent (A).
- component (A2) which is a metallic detergent other than the metal salicylate (A1)
- a conventionally known metallic detergent containing at least one selected from magnesium, calcium and sodium can be used in combination.
- component (A2) include metal sulfonates.
- a metal sulfonate may be used singly, or two or more thereof may be used in combination.
- the amount of component (A2) varies depending on the amount of component (Al); however, it is preferably 0 to 5,000 ppm by weight, more preferably 0 to 2,000 ppm by weight, most preferably 0 to 1,000 ppm by weight, in terms of a concentration [A2] in ppm by weight of metals derived from component (A2) in the lubricant composition.
- metal sulfonate examples include magnesium sulfonate, calcium sulfonate, and sodium sulfonate.
- a commonly-used metallic detergent other than the above-described ones can also be used within a range that does not adversely affect the effects of the present invention.
- magnesium phenate, calcium phenate, and/or a sodium-based detergent may be incorporated.
- Sodium sulfonate, sodium phenate, and sodium salicylate are preferable as the sodium-based detergent.
- These sodium-based detergent may be used singly, or in combination of two or more thereof.
- the sodium-based detergent(s) can be used in combination with the above-described magnesium-based detergent and optional calcium-based detergent.
- the total amount of the metallic detergent (A) in the lubricant composition satisfy following equation (1): A / B ⁇ 4.5
- [A] represents a total concentration in ppm by weight of magnesium, calcium and sodium in the lubricant composition
- [B] represents a concentration in ppm by weight of molybdenum in the lubricant composition.
- the value of [A]/[B] is preferably 3.0 or less, more preferably 2.8 or less, still more preferably 2.6 or less, yet still more preferably 2.5 or less. When the value of [A]/[B] is greater than the above-described upper limit value, excessive wear may occur.
- the lower limit value of [A]/[B] is preferably 0.2, more preferably 0.5, still more preferably 1.
- the molybdenum-based friction modifier is not particularly restricted, and any conventionally known molybdenum-based friction modifier can be used.
- Examples thereof include sulfur-containing organic molybdenum compounds, such as molybdenum dithiophosphate (MoDTP) and molybdenum dithiocarbamate (MoDTC); complexes of a molybdenum compound and a sulfur-containing organic compound or other organic compound; and complexes of an alkenylsuccinimide and a sulfur-containing molybdenum compound, such as molybdenum sulfide or sulfurized molybdic acid.
- MoDTP molybdenum dithiophosphate
- MoDTC molybdenum dithiocarbamate
- molybdenum compound examples include molybdenum oxides, such as molybdenum dioxide and molybdenum trioxide; molybdic acids, such as ortho-molybdic acid, para-molybdic acid, and sulfurized (poly)molybdic acid; molybdates, such as metal salts and ammonium salts of these molybdic acids; molybdenum sulfides, such as molybdenum disulfide, molybdenum trisulfide, molybdenum pentasulfide, and molybdenum polysulfide; sulfurized molybdic acid, and metal salts and amine salts thereof; and molybdenum halides, such as molybdenum chloride.
- molybdenum oxides such as molybdenum dioxide and molybdenum trioxide
- molybdic acids such as ortho-molybdic acid, para-molybdic acid, and sulfurized (poly)moly
- sulfur-containing organic compound examples include alkyl(thio)xanthate, thiaziazole, mercaptothiadiazole, thiocarbonate, tetrahydrocarbyl thiuram disulfide, bis(di(thio)hydrocarbyldithiophosphonate)disulfide, organic (poly)sulfides, and sulfurized esters.
- organic molybdenum compounds such as molybdenum dithiophosphate (MoDTP) and molybdenum dithiocarbamate (MoDTC), are preferable.
- Molybdenum dithiocarbamate is a compound represented by following formula [I]
- Molybdenum dithiophosphate is a compound represented by following formula [II].
- R 1 to R 8 may be the same or different from each other and each represent a monovalent hydrocarbon group having 1 to 30 carbon atoms.
- the hydrocarbon group may be linear or branched.
- Examples of the monovalent hydrocarbon group include linear or branched alkyl groups having 1 to 30 carbon atoms; alkenyl groups having 2 to 30 carbon atoms; cycloalkyl groups having 4 to 30 carbon atoms; and aryl groups, alkylaryl groups and arylalkyl groups, which have 6 to 30 carbon atoms.
- an alkyl group may be bound at any position.
- examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, and an octadecyl group, as well as branched alkyl groups thereof, among which alkyl groups having 3 to 8 carbon atoms are particularly preferable.
- X 1 and X 2 each represent an oxygen atom or a sulfur atom
- Y 1 and Y 2 each represent an oxygen atom or a sulfur atom.
- a sulfur-free organic molybdenum compound can also be used.
- examples thereof include molybdenum-amine complexes, molybdenum-succinimide complexes, molybdenum salts of organic acids, and molybdenum salts of alcohols.
- the friction modifier (B) in the present invention the trinuclear molybdenum compounds described in U.S. Patent No. 5,906,968 can be used as well.
- Component (B) is added in such an amount that allows the concentration [B] in ppm by weight of molybdenum in the lubricant composition to be in a range of 500 to 1,500 ppm by weight, preferably 600 to 1,200 ppm by weight.
- the amount of component (B) is greater than the above-described upper limit, the detergency may be deteriorated, whereas when the amount of component (B) is less than the above-described lower limit, there are cases where friction cannot be sufficiently reduced or the detergency is deteriorated.
- the amount of component (B) preferably satisfies following equation (1): A / B ⁇ 4.5
- [A] represents a total concentration in ppm by weight of magnesium, calcium and sodium in the lubricant composition
- [B] represents a concentration in ppm by weight of molybdenum in the lubricant composition.
- the value of [A]/[B] is preferably 3.0 or less, more preferably 2.8 or less, still more preferably 2.6 or less, yet still more preferably 2.5 or less.
- the lower limit value of [A]/[B] is preferably 0.2, more preferably 0.5, still more preferably 1.0.
- the amount of component (B) preferably satisfies following equation (2): A 1 / B ⁇ 4.5
- [A1] represents a concentration in ppm by weight of metal(s) derived from component (A1) in the lubricant composition.
- the value of [A1]/[B] is preferably less than 3.0, more preferably less than 2.0, still more preferably less than 1.8, particularly preferably less than 1.5.
- the lower limit value of [A1]/[B] is preferably 0.1, more preferably 0.2, still more preferably 0.3.
- the above-described lubricant base oil and components (A1) and (B) are indispensable, and the lubricant composition may also comprise conventionally known anti-wear agent, ashless dispersant and viscosity index improver as optional components.
- anti-wear agent conventionally known anti-wear agents can be used.
- a phosphorus-containing anti-wear agent is preferable, and a zinc dithiophosphate (ZnDTP (also referred to as "ZDDP”)) represented by the following formula is particularly preferable.
- ZnDTP zinc dithiophosphate
- R 1 and R 2 may be the same or different from each other and each represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 26 carbon atoms.
- the monovalent hydrocarbon group is a primary or secondary alkyl group having 1 to 26 carbon atoms; an alkenyl group having 2 to 26 carbon atoms; a cycloalkyl group having 6 to 26 carbon atoms; an aryl, alkylaryl or arylalkyl group having 6 to 26 carbon atoms; or a hydrocarbon group containing an ester bond, ether bond, alcohol group or carboxyl group.
- R 1 and R 2 are each preferably a primary or secondary alkyl group having 2 to 12 carbon atoms, a cycloalkyl group having 8 to 18 carbon atoms or an alkylaryl group having 8 to 18 carbon atoms, and R 1 and R 2 may be the same or different from each other.
- R 1 and R 2 are each preferably a zinc dialkyldithiophosphate
- the primary alkyl group has preferably 3 to 12 carbon atoms, more preferably 4 to 10 carbon atoms.
- the secondary alkyl group has preferably 3 to 12 carbon atoms, more preferably 3 to 10 carbon atoms.
- the above-described zinc dithiophosphate may be used singly, or two or more thereof may be used as a mixture.
- zinc dithiocarbamate (ZnDTC) may be used in combination.
- At least one compound selected from phosphate-based and phosphite-based phosphorus compounds represented by following formulae (3) and (4) as well as metal salts and amine salts thereof can also be used.
- R 3 represents a monovalent hydrocarbon group having 1 to 30 carbon atoms
- R 4 and R 5 each independently represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 30 carbon atoms
- m represents 0 or 1.
- R 6 represents a monovalent hydrocarbon group having 1 to 30 carbon atoms
- R 7 and R 8 each independently represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 30 carbon atoms
- n represents 0 or 1.
- examples of the monovalent hydrocarbon groups having 1 to 30 carbon atoms that are represented by R 3 to R 8 include alkyl groups, cycloalkyl groups, alkenyl groups, alkyl-substituted cycloalkyl groups, aryl groups, alkyl-substituted aryl groups, and arylalkyl groups.
- R 3 to R 8 are each preferably an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 24 carbon atoms, more preferably an alkyl group having 3 to 18 carbon atoms, most preferably an alkyl group having 4 to 15 carbon atoms.
- Examples of the phosphorus compounds represented by formula (3) include phosphorous acid monoesters and hydrocarbyl phosphonites, which have one of the above-described hydrocarbon groups having 1 to 30 carbon atoms; phosphorous acid diesters, monothiophosphorous acid diesters and (hydrocarbyl)phosphonous acid monoesters, which have two of the above-described hydrocarbon groups having 1 to 30 carbon atoms; phosphorous acid triesters and (hydrocarbyl)phosphonous acid diesters, which have three of the above-described hydrocarbon groups having 1 to 30 carbon atoms; and mixtures thereof.
- Metal salts or amine salts of the phosphorus compounds represented by formula (3) or (4) can be obtained by allowing, for example, a metal base (e.g., a metal oxide, a metal hydroxide, a metal carbonate, or a metal chloride) or a nitrogen compound (e.g., ammonia, or an amine compound having only a hydrocarbon group or hydroxyl group-containing hydrocarbon group having 1 to 30 carbon atoms in the molecule), to act on a phosphorus compound represented by formula (3) or (4) and subsequently neutralizing some or all of residual acidic hydrogens.
- a metal base e.g., a metal oxide, a metal hydroxide, a metal carbonate, or a metal chloride
- a nitrogen compound e.g., ammonia, or an amine compound having only a hydrocarbon group or hydroxyl group-containing hydrocarbon group having 1 to 30 carbon atoms in the molecule
- Examples of a metal in the above-described metal base include alkali metals, such as lithium, sodium, potassium, and cesium; alkaline earth metals, such as calcium, magnesium, and barium; and heavy metals (excluding molybdenum), such as zinc, copper, iron, lead, nickel, silver, and manganese.
- alkali metals such as lithium, sodium, potassium, and cesium
- alkaline earth metals such as calcium, magnesium, and barium
- heavy metals excluding molybdenum
- zinc zinc, copper, iron, lead, nickel, silver, and manganese.
- alkaline earth metals such as calcium and magnesium, and zinc are preferable, and zinc is particularly preferable.
- the anti-wear agent is incorporated in an amount of usually 0.1 to 5.0% by weight, preferably 0.2 to 3.0% by weight.
- the ashless dispersant examples include nitrogen-containing compounds having at least one linear or branched alkyl or alkenyl group having 40 to 500 carbon atoms, preferably 60 to 350 carbon atoms, in the molecule, and derivatives thereof; Mannich dispersants; mono- or bis-succinimides (e.g., alkenylsuccinimides); benzylamines having at least one alkyl or alkenyl group having 40 to 500 carbon atoms in the molecule; polyamines having at least one alkyl or alkenyl group having 40 to 400 carbon atoms in the molecule; and modified products thereof obtained by modification with a boron compound, carboxylic acid, phosphoric acid or the like. Any one or more of these ashless dispersants can be arbitrarily selected and incorporated. It is particularly preferable that the lubricant composition comprise an alkenylsuccinimide.
- a method of producing the above-described succinimides is not particularly restricted and, for example, and the succinimides can be obtained by allowing a compound having an alkyl or alkenyl group having 40 to 500 carbon atoms to react with maleic anhydride at 100 to 200°C and subsequently allowing the resulting alkyl succinate or alkenyl succinate to react with a polyamine.
- the polyamine include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.
- Examples of the derivatives of nitrogen-containing compounds exemplified above as the ashless dispersant include compounds modified with a so-called "oxygen-containing organic compound", which are obtained by allowing a monocarboxylic acid having 1 to 30 carbon atoms (e.g., a fatty acid), a polycarboxylic acid having 2 to 30 carbon atoms (e.g., oxalic acid, phthalic acid, trimellitic acid, or pyromellitic acid) or an anhydride thereof, an ester compound thereof, an alkylene oxide having 2 to 6 carbon atoms, or a hydroxy(poly)oxyalkylene carbonate to act on the above-described nitrogen-containing compounds and subsequently neutralizing or amidating some or all of residual amino groups and/or imino groups; so-called "boron-modified compounds", which are obtained by allowing boric acid to act on the above-described nitrogen-containing compounds and subsequently neutralizing or amidating some or all of residual amino groups and/or imino groups
- boric acid-modified compounds of alkenylsuccinimides particularly boric acid-modified compounds of bis-type alkenylsuccinimides, can further improve the heat resistance when used in combination with the above-described base oil.
- the amount of the ashless dispersant is 20% by weight or less, preferably 15% by weight or less, still more preferably 5% by weight or less, based on the total amount of the composition.
- a boron-containing ashless dispersant can also be used as a mixture with a boron-free ashless dispersant.
- the content ratio thereof is not particularly restricted; however, it is appropriate that the amount of boron contained in the composition be preferably 0.001 to 0.2% by weight, more preferably 0.003 to 0.1% by weight, most preferably 0.005 to 0.05% by weight, based on the total amount of the composition.
- the number-average molecular weight (Mn) of the ashless dispersant is preferably not less than 2,000, more preferably not less than 2,500, still more preferably not less than 3,000, most preferably not less than 5,000, but preferably not higher than 15,000.
- Mn number-average molecular weight
- Examples of the above-described viscosity index improver include those containing a polymethacrylate, a dispersion-type polymethacrylate, an olefin copolymer (e.g., a polyisobutylene or an ethylene-propylene copolymer), a dispersion-type olefin copolymer, a polyalkylstyrene, a hydrogenated styrene-butadiene copolymer, a styrene-maleic anhydride ester copolymer, a star isoprene or the like.
- an olefin copolymer e.g., a polyisobutylene or an ethylene-propylene copolymer
- a dispersion-type olefin copolymer e.g., a polyalkylstyrene, a hydrogenated styrene-butadiene copolymer, a
- a comb-shaped polymer which contains, in its main chain, at least a repeating unit based on a polyolefin macromer and a repeating unit based on an alkyl (meth)acrylate containing an alkyl group having 1 to 30 carbon atoms, can also be used.
- the viscosity index improver is usually composed of the above-described polymer and a diluent oil.
- the content of the viscosity index improver is preferably 0.01 to 20% by weight, more preferably 0.02 to 10% by weight, most preferably 0.05 to 5% by weight, in terms of the polymer amount based on the total amount of the composition.
- the content of the viscosity index improver is less than the above-described lower limit value, the viscosity-temperature characteristics and the low-temperature viscosity characteristics may be deteriorated.
- the content of the viscosity index improver is higher than the above-described upper limit value, not only the viscosity-temperature characteristics and the low-temperature viscosity characteristics may be deteriorated, but also the production cost is largely increased.
- additives that are commonly used in lubricant compositions can be used, and examples thereof include an antioxidant, a friction modifier other than above-described component (B), a corrosion inhibitor, a rust inhibitor, a pour-point depressant, a demulsifier, a metal deactivator, and an anti-foaming agent.
- antioxidants examples include phenolic and amine-based ashless antioxidants, and metal-based antioxidants, such as copper-based and molybdenum-based antioxidants.
- phenolic ashless antioxidants examples include 4,4'-methylene-bis(2,6-di- tert -butylphenol), 4,4'-bis(2,6-di- tert -butylphenol) and isooctyl-3-(3,5-di- t -butyl-4-hydroxyphenyl)propionate
- examples of the amine-based ashless antioxidants include phenyl- ⁇ -naphthylamine, alkylphenyl- ⁇ -naphthylamine, and dialkyldiphenylamine.
- the antioxidant is incorporated into the lubricant composition usually in an amount of 0.1 to 5% by weight.
- Examples of the friction modifier other than above-described component (B) include esters, amines, amides, and sulfurized esters.
- the friction modifier is incorporated into the lubricant composition usually in an amount of 0.01 to 3% by weight.
- Examples of the corrosion inhibitor include benzotriazole-based, tolyltriazole-based, thiadiazole-based, and imidazole-based compounds.
- Examples of the rust inhibitor include petroleum sulfonates, alkylbenzene sulfonates, dinonylnaphthalene sulfonates, alkenylsuccinic acid esters, and polyhydric alcohol esters. The rust inhibitor and the corrosion inhibitor are each incorporated into the lubricant composition usually in an amount of 0.01 to 5% by weight.
- pour-point depressant for example, a polymethacrylate-based polymer that is compatible with the lubricant base oil to be used can be selected.
- the pour-point depressant is incorporated into the lubricant composition usually in an amount of 0.01 to 3% by weight.
- the demulsifier examples include polyalkylene glycol-based nonionic surfactants, such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, and polyoxyethylene alkylnaphthyl ethers.
- the demulsifier is incorporated into the lubricant composition usually in an amount of 0.01 to 5% by weight.
- the metal deactivator examples include imidazolines, pyrimidine derivatives, alkylthiadiazoles, mercaptobenzothiazoles, benzotriazoles and derivatives thereof, 1,3,4-thiadiazole polysulfides, 1,3,4-thiadiazolyl-2,5-bisdialkyl dithiocarbamates, 2-(alkyldithio)benzimidazoles, and ⁇ -(o-carboxybenzylthio)propionitrile.
- the metal deactivator is incorporated into the lubricant composition usually in an amount of 0.01 to 3% by weight.
- the anti-foaming agent examples include silicone oils having a kinematic viscosity at 25°C of 1,000 to 100,000 mm 2 /s, alkenylsuccinic acid derivatives, esters of a polyhydroxy aliphatic alcohol and a long-chain fatty acid, methyl salicylate, and o -hydroxybenzyl alcohols.
- the anti-foaming agent is incorporated into the lubricant composition usually in an amount of 0.001 to 1% by weight.
- an alkali borate-based additive can be added.
- the alkali borate-based additive contains an alkali metal borate hydrate and can be represented by the following formula: M 2 O ⁇ xB 2 O 3 ⁇ yH 2 O
- M represents an alkali metal
- x represents 2.5 to 4.5
- y represents 1.0 to 4.8.
- the alkali borate-based additive examples include lithium borate hydrate, sodium borate hydrate, potassium borate hydrate, rubidium borate hydrate and cesium borate hydrate, among which potassium borate hydrate and sodium borate hydrate are preferable, and potassium borate hydrate is particularly preferable.
- the average particle size of these alkali metal borate hydrate particles is generally 1 micron ( ⁇ ) or smaller.
- the ratio of boron to alkali metal is preferably in a range of about 2.5:1 to 4.5:1.
- the amount of the alkali borate-based additive to be added is 0.002 to 0.05% by weight in terms of boron amount based on the total amount of the lubricant composition.
- the CCS viscosity at -35°C of the lubricant composition of the present invention is not restricted; however, it is preferably 6.2 Pa ⁇ s or less, more preferably 5.0 Pa ⁇ s or less, still more preferably 4.0 Pa ⁇ s or less, most preferably 3.5 Pa ⁇ s or less.
- the amount of molybdenum contained therein and the CCS viscosity at -35°C satisfy following equation (5): CCS viscosity / B ⁇ 0.01 wherein [CCS viscosity] represents a value (Pa ⁇ s) of the CCS viscosity at -35°C of the lubricant composition, and [B] represents the concentration in ppm by weight of molybdenum in the lubricant composition.
- the value of [CCS viscosity]/[B] is more preferably 0.008 or less, still more preferably 0.005 or less. When this value is larger than 0.01, the torque reduction ratio may be reduced and the detergency may be deteriorated.
- the lower limit value of [CCS viscosity]/[B] is not restricted; however, it is preferably 0.002, more preferably 0.003.
- the high-temperature high-shear viscosity (HTHS viscosity) at 150°C of the lubricant composition of the present invention is not restricted; however, it is preferably 1.7 to 2.9 mPa ⁇ s, more preferably 2.0 to 2.6 mPa ⁇ s.
- the kinematic viscosity at 100°C of the lubricant composition of the present invention is not restricted; however, it is preferably less than 9.3 mm 2 /s, more preferably less than 8.2 mm 2 /s.
- the lubricant composition of the present invention has sufficient friction characteristics and wear characteristics and exerts an effect of attaining a high torque reduction ratio even at a low viscosity; therefore, the lubricant composition of the present invention can be suitably used for internal combustion engines as well as supercharged gasoline engines.
- Molybdenum-based friction modifier MoDTC (a compound represented by above-described formula [1], wherein X 1 and X 2 are both O, and Y 1 and Y 2 are both S; molybdenum content: 10% by weight)
- Lubricant compositions were each prepared by mixing the respective components in the amounts indicated in Tables 1 and 3.
- the amounts of the magnesium-based detergent, calcium-based detergent and molybdenum-based friction modifier indicated in Tables 1 and 3 are concentrations in terms of the contents (ppm by weight) of magnesium, calcium and molybdenum based on the total amount of each lubricant composition ([Mg], [Ca] and [B] in the order mentioned), respectively.
- the amounts of the anti-wear agent and other additives are in parts by weight based on the total amount (100 parts by weight) of each lubricant composition.
- [A] represents a total concentration in ppm by weight of all magnesium and calcium contained in each lubricant composition (i.e. including Mg and Ca derived from magnesium sulfonate and calcium sulfonate, respectively), and [A1] represents a total concentration in ppm by weight of magnesium and calcium derived from the metal salicylate(s) (A1) contained in each lubricant composition (i.e. [Ca] + [Mg]).
- [A1]/[A] represents a ratio (% by weight) of [A1], which is the total concentration in ppm by weight of magnesium and calcium derived from the metal salicylate(s), based on [A], which is the total concentration in ppm by weight of all magnesium and calcium contained in each lubricant composition.
- the high-temperature high-shear viscosity at 150°C was measured in accordance with ASTM D4683.
- the CCS viscosity at -35°C was measured in accordance with ASTM D5293.
- the kinematic viscosity at 100°C was measured in accordance with ASTM D445.
- the torque was measured in a motoring test with a gasoline engine.
- a TOYOTA 2ZR-FE 1.8L in-line 4-cylinder engine was used as the engine, and a torque meter was arranged between a motor and the engine to measure the torque at an oil temperature of 80°C and an engine speed of 700 rpm.
- the torque was also measured in the same manner using a commercially available GF-5 0W-20 oil as a standard oil.
- the torque (T) of each test composition was compared with the torque (T 0 ) of the standard oil, and the reduction ratio from the torque of the standard oil, ( ⁇ (T 0 - T)/T 0 ⁇ ⁇ 100) (%), was calculated.
- a higher reduction ratio indicates superior fuel efficiency.
- a reduction ratio of 5.5% or higher was regarded as satisfactory.
- the diameter of shell wear scar was measured in accordance with the shell four-ball test (ASTM D4172), except that the rotation speed, the load, the testing temperature and the testing time were set at 1,800 rpm, 40 kgf, 90°C and 30 minutes, respectively. A wear scar diameter of 0.7 mm or smaller was regarded as satisfactory.
- Each lubricant composition and air were allowed to continuously flow in a glass tube of 2 mm in inner diameter for 16 hours at rates of 0.3 mL/hr and 10 mL/sec, respectively, while maintaining the temperature of the glass tube at 270°C.
- a lacquer adhered to the glass tube was compared with a color chart and evaluated with a score of 10 when the lacquer was transparent or a score of 0 when the lacquer was black. A higher score indicates superior high-temperature detergency. A score of 5.0 or higher was regarded as satisfactory.
- Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10
- Example 11 Example 12 Lubricant base oil balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance balance
- Example 1 Example 2
- Example 3 Example 4
- Example 5 Example 6
- Example 7 Example 8
- Example 9 Example 10
- Example 11 Example 12 Evaluation results KV100 mm 2 /s 6.8 6.7 6.8 6.8 6.7 6.6 6.9 6.9 6.6 6.6 6.7 6.9 HTHS 150 MPa ⁇ s 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.4 2.4 CCS viscosity Pa ⁇ s 3.2 3.1 3.4 3.3 3.3 3.4 3.4 3.4 3.1 3.0 3.1 3.2 Torque reduction ratio % 5.99 7.71 8.04 6.40 7.40 7.43 7.45 8.66 7.50 7.29 7.40 6.90 Diameter of shell wear scar mm 0.64 0.63 0.68 0.55 0.62 0.61 0.66 0.66 0.63 0.52 0.61 0.61 Hot tube 270°C 7.5 7.5 6.5 5.5 5.5 8.5 5.5 7.5 7.5 6.0 5.5 8.0 [CCS viscosity]/[B] 0.0046 0.0044 0.0049 0.0047
- compositions of Comparative Examples 1 to 3 in which the content of calcium salicylate (A1) was high had a low torque reduction ratio
- the composition of Comparative Example 6 containing a large amount of magnesium salicylate (A) caused a large wear had a low torque reduction ratio
- the compositions of Comparative Examples 4 and 5 in which the amount of the molybdenum-based friction modifier (B) was less than the lower limit of the present invention had a low torque reduction ratio and exhibited poor high-temperature detergency.
- the compositions of Comparative Examples 7 and 8 which did not contain any metal salicylate not only had a low torque reduction ratio but also exhibited poor high-temperature detergency.
- the lubricant compositions according to the present invention caused only a small wear and exhibited a high torque reduction ratio and excellent high-temperature detergency, despite having a low kinematic viscosity at 100°C.
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Abstract
Provided is a lubricant composition which is capable of reducing friction, while ensuring anti-wear properties even if the viscosity thereof is decreased. A lubricant composition which contains a lubricant base oil, (A1) a metal salicylate and (B) a molybdenum-based friction regulator, and which is characterized in that: the amount of the component (B) is 500 to 1,500 ppm by mass in terms of the molybdenum concentration [B] in the lubricant composition; the component (A1) is calcium salicylate, magnesium salicylate or a combination thereof; the calcium concentration [Ca] based on the calcium salicylate in the lubricant composition is 0 to 1,800 ppm by mass; the magnesium concentration [Mg] based on the magnesium salicylate in the lubricant composition is 0 to 1,800 ppm by mass; and the total of the calcium concentration [Ca] and the magnesium concentration [Mg] is 200 to 3,000 ppm by mass.
Description
- The present invention relates to a lubricant composition. More specifically, the present invention relates to a lubricant composition for an internal combustion engine, particularly a lubricant composition for a gasoline engine.
- Lubricant compositions are widely used in the automotive field for internal combustion engines, automatic transmissions, gear oils and the like. In recent years, such lubricant compositions are demanded to have a reduced viscosity for improving the fuel efficiency; however, since a reduction in viscosity leads to a reduced oil film thickness, friction cannot be sufficiently reduced. Accordingly, molybdenum dithiocarbamate (MoDTC) capable of reducing friction by yielding molybdenum disulfide under boundary lubrication conditions has been conventionally used. In such cases, MoDTC is usually used in combination with a calcium-based detergent (e.g., Japanese Unexamined Patent Publication (Kokai) No.
2013-199594 - It is also known to use a magnesium-based detergent as a detergent (e.g., Japanese Unexamined Patent Publication (Kokai) No.
2011-184566 2006-328265 -
- [PTL 1] Japanese Unexamined Patent Publication (Kokai) No.
2013-199594 - [PTL 2] Japanese Unexamined Patent Publication (Kokai) No.
2011-184566 - [PTL 3] Japanese Unexamined Patent Publication (Kokai) No.
2006-328265 - An object of the present invention is to provide a lubricant composition capable of reducing friction while ensuring anti-wear properties even at a reduced viscosity, preferably a lubricant composition used in an internal combustion engine, more preferably a lubricant composition used in a supercharged gasoline engine.
- The present inventors intensively studied to discover that the above-described object can be achieved by adding a specific amount of at least one metal salicylate selected from calcium salicylate and magnesium salicylate and a specific amount of a molybdenum-based friction modifier to a lubricant base oil.
- In other words, the present invention is a lubricant composition containing: a lubricant base oil; (A1) a metal salicylate; and (B) a molybdenum-based friction modifier,
wherein
the amount of component (B) is in a range of 500 to 1,500 ppm by weight in terms of a concentration [B] in ppm by weight of molybdenum in the lubricant composition,
component (A1) is any one of calcium salicylate, magnesium salicylate, and a combination thereof,
the amount of calcium salicylate is 0 to 1,800 ppm by weight in terms of a concentration [Ca] in ppm by weight of calcium derived from calcium salicylate in the lubricant composition,
the amount of magnesium salicylate is 0 to 1,800 ppm by weight in terms of a concentration [Mg] in ppm by weight of magnesium derived from magnesium salicylate in the lubricant composition, and
a total of [Ca] and [Mg] is in a range of 200 to 3,000 ppm by weight. - In a preferable embodiment of the present invention, the lubricant composition further includes at least one of following characteristic features (1) to (10):
- (1) the lubricant composition comprising (A) a metallic detergent, wherein the lubricant composition comprises the metal salicylate (A1) in an amount of 5 to 100% by weight based on the total weight of component (A) in terms of a ratio of [Ca] and [Mg] based on a total concentration [A] in ppm by weight of metals derived from the metallic detergent in the lubricant composition;
- (2) the lubricant composition optionally further comprises a metallic detergent other than component (A1) as the metallic detergent (A), wherein the weight of component (A1) based on the total weight of the metallic detergent (A) is in a range of 5 to 100% by weight;
- (3) the metal salicylate (A1) is magnesium salicylate and calcium salicylate;
- (4) the metal salicylate (A1) is at least one kind of magnesium salicylate;
- (5) the lubricant composition further comprises (A2) a metallic detergent other than component (A1) as the metallic detergent (A), component (A2) comprises at least one selected from magnesium, calcium and sodium, and the total content of the metallic detergent (A) satisfies following equation (1):
- (6) the content of the metal salicylate (A1) satisfies following equation (2):
- (7) the CCS viscosity at -35°C is 6.2 Pa·s or less;
- (8) the high-temperature high-shear viscosity (HTHS viscosity) at 150°C is 1.7 to 2.9 mPa·s;
- (9) the kinematic viscosity at 100°C is less than 9.3 mm2/s; and
- (10) the lubricant composition is for an internal combustion engine.
- The present invention also relates to a method of reducing friction while maintaining low-wear properties by using the above-described lubricant composition or the lubricant composition according to any one of embodiments (1) to (10).
- The lubricant composition of the present invention is capable of reducing friction while ensuring anti-wear properties even at a reduced viscosity, and can thus be suitably used as a lubricant composition for internal combustion engines, particularly as a lubricant composition for supercharged gasoline engines.
- In the present invention, the lubricant base oil is not particularly restricted. The lubricant base oil may be any one of mineral oils and synthetic oils, and these oils can be used singly or as a mixture.
- Examples of mineral oils include oils obtained by distilling an atmospheric residue, which is generated by atmospheric distillation of crude oil, under reduced pressure and refining the resulting lubricant fraction by one or more treatments, such as solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, and hydrorefining; wax-isomerized mineral oils; GTL (Gas-to-Liquid) base oils; ATL (Asphalt-to-Liquid) base oils; vegetable oil-derived base oils; and mixed base oils thereof.
- Examples of the synthetic oils include polybutenes and hydrogenated products thereof; poly-α-olefins, such as 1-octene oligomer and 1-decene oligomer, and hydrogenated products thereof; monoesters, such as 2-ethylhexyl laurate, 2-ethylhexyl palmitate, and 2-ethylhexyl stearate; diesters, such as ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, and di-2-ethylhexyl sebacate; polyol esters, such as neopentyl glycol di-2-ethylhexanoate, neopentyl glycol di-n-octanoate, neopentyl glycol di-n-decanoate, trimethylolpropane tri-n-octanoate, trimethylolpropane tri-n-decanoate, pentaerythritol tetra-n-pentanoate, pentaerythritol tetra-n-hexanoate, and pentaerythritol tetra-2-ethylhexanoate; aromatic synthetic oils, such as alkylnaphthalenes, alkylbenzenes, and aromatic esters; and mixtures thereof.
- The kinematic viscosity (mm2/s) at 100°C of the lubricant base oil is not particularly restricted; however, it is preferably 2 to 15 mm2/s, more preferably 3 to 10 mm2/s, still more preferably 3 to 8 mm2/s, most preferably 3 to 6 mm2/s. By this, a lubricant composition which not only sufficiently forms an oil film and provides excellent lubricity but also has less evaporation loss can be obtained.
- The viscosity index (VI) of the lubricant base oil is not particularly restricted; however, it is preferably 100 or higher, more preferably 120 or higher, most preferably 130 or higher. By this, the viscosity at low temperatures can be reduced while securing an oil film at high temperatures.
- The lubricant composition of the present invention is characterized by comprising, as a metallic detergent (A), a metal salicylate (A1) which is calcium salicylate, magnesium salicylate or a combination thereof in the below-described specific range of amount. The lubricant composition of the present invention may further comprise other metallic detergent than calcium salicylate and magnesium salicylate as the metallic detergent (A), and it is appropriate that the weight ratio of component (A1) based on the total weight of the metallic detergent (A) be in a range of 5 to 100% by weight, preferably 10 to 100% by weight, more preferably 15 to 100% by weight, particularly preferably 20 to 100% by weight, most preferably 50 to 100% by weight, in terms of a ratio of [Ca] and [Mg] based on a total concentration [A] in ppm by weight of metals derived from the metallic detergent in the lubricant composition, wherein [Ca] is a concentration in ppm by weight of calcium derived from calcium salicylate in the lubricant composition, and [Mg] is a concentration in ppm by weight of magnesium derived from magnesium salicylate in the lubricant composition. By containing at least one selected from calcium salicylate and magnesium salicylate in a specific amount as the metallic detergent, the lubricant composition can ensure high-temperature detergency and rust inhibition that are required as a lubricant. In addition, the lubricant composition can reduce friction and, therefore, can reduce torque. This is advantageous particularly from the standpoint of fuel efficiency characteristics.
- As for the amount of component (A1) in the lubricant composition of the present invention, the amount of calcium salicylate is 0 to 1,800 ppm by weight, preferably 0 to 1,600 ppm by weight, in terms of the concentration [Ca] in ppm by weight of calcium in the lubricant composition; the amount of magnesium salicylate is 0 to 1,800 ppm by weight, preferably 0 to 1,600 ppm by weight, in terms of the concentration [Mg] in ppm by weight of magnesium in the lubricant composition; and the value of [Ca] + [Mg] is in a range of 200 to 3,000 ppm by weight, preferably 300 to 2,500 ppm by weight, more preferably 400 to 2,000 ppm by weight. When the amount of component (A1) is greater than the above-described upper limit, excessive wear may occur and a sludge may be generated, whereas when the amount of component (A1) is smaller than the above-described lower limit, the friction-reducing effect is low.
- In the present invention, as described above, at least one selected from magnesium salicylate and calcium salicylate is indispensable as the metal salicylate. Only a single kind of these metal salicylates may be used, or two or more kinds thereof may be used in combination. A combination of magnesium salicylate and calcium salicylate, or magnesium salicylate alone is preferable, and magnesium salicylate is more preferable.
- When component (A1) is magnesium salicylate alone, it is appropriate that the content thereof in terms of the concentration [Mg] in ppm by weight of magnesium derived from magnesium salicylate in the lubricant composition be in a range of 200 to 1,800 ppm by weight, preferably 250 to 1,500 ppm by weight, more preferably 300 to 1,200 ppm by weight, most preferably 400 to 1,000 ppm. When component (A1) is calcium salicylate alone, it is appropriate that the content thereof in terms of the concentration [Ca] in ppm by weight of calcium derived from calcium salicylate in the lubricant composition be in a range of 200 to 1,800 ppm by weight, preferably 300 to 1,600 ppm by weight, more preferably 500 to 1,400 ppm by weight. When component (A1) is a combination of magnesium salicylate and calcium salicylate, it is appropriate that a total of [Ca] and [Mg] satisfy a range of 200 to 3,000 ppm by weight, preferably 300 to 2,500 ppm by weight, more preferably 400 to 2,000 ppm by weight. Particularly, it is appropriate that [Mg] be in a range of 100 to 1,600 ppm by weight, preferably 150 to 1,400 ppm by weight, more preferably 200 to 1,200 ppm by weight, most preferably 300 to 1,000 ppm, and that [Ca] be in a range of 100 to 1,600 ppm by weight, preferably 300 to 1,500 ppm by weight, more preferably 500 to 1,400 ppm by weight.
- The magnesium content in magnesium salicylate and the calcium content in calcium salicylate are each preferably 0.5 to 20% by weight, more preferably 1 to 16% by weight, most preferably 2 to 14% by weight. The amount of component (A1) to be added is adjusted such that magnesium and calcium are incorporated into the lubricant composition in the above-described respective ranges of amount.
- In particular, the metal salicylate (A1) is preferably an overbased metal salicylate, more preferably a combination of magnesium salicylate and calcium salicylate, especially preferably overbased magnesium salicylate. By this, acid neutralization performance required for a lubricant can be ensured. When overbased magnesium salicylate is used, a neutral magnesium- or calcium-based detergent may be mixed therewith. When overbased calcium salicylate is used, a neutral calcium-based detergent may be used in combination.
- The total base number of the metal salicylate (A1) is not restricted; however, it is preferably 20 to 600 mg KOH/g, more preferably 50 to 500 mg KOH/g, most preferably 100 to 450 mg KOH/g. By this, acid neutralization performance, high-temperature detergency and rust inhibition that are required for a lubricant can be ensured. When two or more metal salicylates are used as a mixture, the base number of the mixture is preferably in the above-described range.
-
- In equation (2), [A1] represents a total concentration (i.e. [Ca] + [Mg]) in ppm by weight of magnesium and calcium that are derived from the magnesium salicylate and calcium salicylate (A1) in the lubricant composition, and [B] is as described above.
- The value of [A1]/[B] is preferably less than 3.0, more preferably less than 2, still more preferably less than 1.8, particularly preferably less than 1.5. When the value of [A1]/[B] is greater than the above-described upper limit, the torque-reducing effect may be low. The lower limit value of [A1]/[B] is preferably 0.1, more preferably 0.2, still more preferably 0.3.
- In a preferable embodiment, as described above, the lubricant composition of the present invention comprises only magnesium salicylate as the metal salicylate (A1), or a combination of magnesium salicylate and calcium salicylate as component (A1). The lubricant composition of the present invention may further contain (A2) a metallic detergent other than the calcium salicylate and magnesium salicylate (A1) as the metallic detergent (A). In this case, as described above, it is appropriate that the weight ratio of component (A1) based on the total weight of the metallic detergent (A) be 5 to 100% by weight, preferably 10 to 100% by weight, more preferably 15 to 100% by weight, particularly preferably 20 to 100% by weight, most preferably 50 to 100% by weight, in terms the ratio of [Ca] and [Mg] based on the total concentration [A] in ppm by weight of metals derived from the metallic detergent in the lubricant composition. It is particularly appropriate that the percentage (% by weight) of magnesium salicylate based on the total weight of the metallic detergent (A) be 5 to 100% by weight, preferably 10 to 80% by weight, more preferably 10 to 60% by weight, particularly preferably 10 to 40% by weight, in terms the percentage of [Mg] based on the total concentration [A] in ppm by weight of metals derived from the metallic detergent in the lubricant composition. In a more preferable embodiment, the lubricant composition of the present invention comprises only magnesium salicylate, or only a combination of magnesium salicylate and calcium salicylate, as the metallic detergent (A).
- In the lubricant composition of the present invention, as component (A2) which is a metallic detergent other than the metal salicylate (A1), a conventionally known metallic detergent containing at least one selected from magnesium, calcium and sodium can be used in combination. Examples of component (A2) include metal sulfonates. A metal sulfonate may be used singly, or two or more thereof may be used in combination. By incorporating a metal sulfonate, high-temperature detergency and rust inhibition that are required for a lubricant can be better ensured. The amount of component (A2) varies depending on the amount of component (Al); however, it is preferably 0 to 5,000 ppm by weight, more preferably 0 to 2,000 ppm by weight, most preferably 0 to 1,000 ppm by weight, in terms of a concentration [A2] in ppm by weight of metals derived from component (A2) in the lubricant composition.
- Examples of the metal sulfonate include magnesium sulfonate, calcium sulfonate, and sodium sulfonate.
- Further, a commonly-used metallic detergent other than the above-described ones can also be used within a range that does not adversely affect the effects of the present invention. For example, magnesium phenate, calcium phenate, and/or a sodium-based detergent may be incorporated. Sodium sulfonate, sodium phenate, and sodium salicylate are preferable as the sodium-based detergent. These sodium-based detergent may be used singly, or in combination of two or more thereof. By incorporating a sodium-based detergent(s), high-temperature detergency and rust inhibition that are required for a lubricant can be ensured. The sodium-based detergent(s) can be used in combination with the above-described magnesium-based detergent and optional calcium-based detergent.
-
- In equation (1), [A] represents a total concentration in ppm by weight of magnesium, calcium and sodium in the lubricant composition, and [B] represents a concentration in ppm by weight of molybdenum in the lubricant composition.
- The value of [A]/[B] is preferably 3.0 or less, more preferably 2.8 or less, still more preferably 2.6 or less, yet still more preferably 2.5 or less. When the value of [A]/[B] is greater than the above-described upper limit value, excessive wear may occur. The lower limit value of [A]/[B] is preferably 0.2, more preferably 0.5, still more preferably 1.
- The molybdenum-based friction modifier is not particularly restricted, and any conventionally known molybdenum-based friction modifier can be used. Examples thereof include sulfur-containing organic molybdenum compounds, such as molybdenum dithiophosphate (MoDTP) and molybdenum dithiocarbamate (MoDTC); complexes of a molybdenum compound and a sulfur-containing organic compound or other organic compound; and complexes of an alkenylsuccinimide and a sulfur-containing molybdenum compound, such as molybdenum sulfide or sulfurized molybdic acid. Examples of the molybdenum compound include molybdenum oxides, such as molybdenum dioxide and molybdenum trioxide; molybdic acids, such as ortho-molybdic acid, para-molybdic acid, and sulfurized (poly)molybdic acid; molybdates, such as metal salts and ammonium salts of these molybdic acids; molybdenum sulfides, such as molybdenum disulfide, molybdenum trisulfide, molybdenum pentasulfide, and molybdenum polysulfide; sulfurized molybdic acid, and metal salts and amine salts thereof; and molybdenum halides, such as molybdenum chloride. Examples of the sulfur-containing organic compound include alkyl(thio)xanthate, thiaziazole, mercaptothiadiazole, thiocarbonate, tetrahydrocarbyl thiuram disulfide, bis(di(thio)hydrocarbyldithiophosphonate)disulfide, organic (poly)sulfides, and sulfurized esters. Particularly, organic molybdenum compounds, such as molybdenum dithiophosphate (MoDTP) and molybdenum dithiocarbamate (MoDTC), are preferable.
-
- In above-described formulae [I] and [II], R1 to R8 may be the same or different from each other and each represent a monovalent hydrocarbon group having 1 to 30 carbon atoms. The hydrocarbon group may be linear or branched. Examples of the monovalent hydrocarbon group include linear or branched alkyl groups having 1 to 30 carbon atoms; alkenyl groups having 2 to 30 carbon atoms; cycloalkyl groups having 4 to 30 carbon atoms; and aryl groups, alkylaryl groups and arylalkyl groups, which have 6 to 30 carbon atoms. In the arylalkyl groups, an alkyl group may be bound at any position. More specifically, examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, and an octadecyl group, as well as branched alkyl groups thereof, among which alkyl groups having 3 to 8 carbon atoms are particularly preferable. Further, X1 and X2 each represent an oxygen atom or a sulfur atom, and Y1 and Y2 each represent an oxygen atom or a sulfur atom.
- As component (B), a sulfur-free organic molybdenum compound can also be used. Examples thereof include molybdenum-amine complexes, molybdenum-succinimide complexes, molybdenum salts of organic acids, and molybdenum salts of alcohols.
- Moreover, as the friction modifier (B) in the present invention, the trinuclear molybdenum compounds described in
U.S. Patent No. 5,906,968 can be used as well. - Component (B) is added in such an amount that allows the concentration [B] in ppm by weight of molybdenum in the lubricant composition to be in a range of 500 to 1,500 ppm by weight, preferably 600 to 1,200 ppm by weight. When the amount of component (B) is greater than the above-described upper limit, the detergency may be deteriorated, whereas when the amount of component (B) is less than the above-described lower limit, there are cases where friction cannot be sufficiently reduced or the detergency is deteriorated.
-
- In equation (1), [A] represents a total concentration in ppm by weight of magnesium, calcium and sodium in the lubricant composition, and [B] represents a concentration in ppm by weight of molybdenum in the lubricant composition.
- The value of [A]/[B] is preferably 3.0 or less, more preferably 2.8 or less, still more preferably 2.6 or less, yet still more preferably 2.5 or less. The lower limit value of [A]/[B] is preferably 0.2, more preferably 0.5, still more preferably 1.0.
-
- In equation (2), [A1] represents a concentration in ppm by weight of metal(s) derived from component (A1) in the lubricant composition. The value of [A1]/[B] is preferably less than 3.0, more preferably less than 2.0, still more preferably less than 1.8, particularly preferably less than 1.5. When the value of [A1]/[B] is greater than the above-described upper limit, the torque-reducing effect may be low. The lower limit value of [A1]/[B] is preferably 0.1, more preferably 0.2, still more preferably 0.3.
- In the lubricant composition of the present invention, the above-described lubricant base oil and components (A1) and (B) are indispensable, and the lubricant composition may also comprise conventionally known anti-wear agent, ashless dispersant and viscosity index improver as optional components.
-
- In this formula, R1 and R2 may be the same or different from each other and each represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 26 carbon atoms. The monovalent hydrocarbon group is a primary or secondary alkyl group having 1 to 26 carbon atoms; an alkenyl group having 2 to 26 carbon atoms; a cycloalkyl group having 6 to 26 carbon atoms; an aryl, alkylaryl or arylalkyl group having 6 to 26 carbon atoms; or a hydrocarbon group containing an ester bond, ether bond, alcohol group or carboxyl group. R1 and R2 are each preferably a primary or secondary alkyl group having 2 to 12 carbon atoms, a cycloalkyl group having 8 to 18 carbon atoms or an alkylaryl group having 8 to 18 carbon atoms, and R1 and R2 may be the same or different from each other. Particularly, R1 and R2 are each preferably a zinc dialkyldithiophosphate, and the primary alkyl group has preferably 3 to 12 carbon atoms, more preferably 4 to 10 carbon atoms. The secondary alkyl group has preferably 3 to 12 carbon atoms, more preferably 3 to 10 carbon atoms. The above-described zinc dithiophosphate may be used singly, or two or more thereof may be used as a mixture. In addition, zinc dithiocarbamate (ZnDTC) may be used in combination.
-
-
- In above-described formula (4), R6 represents a monovalent hydrocarbon group having 1 to 30 carbon atoms; R7 and R8 each independently represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 30 carbon atoms; and n represents 0 or 1.
- In formulae (3) and (4), examples of the monovalent hydrocarbon groups having 1 to 30 carbon atoms that are represented by R3 to R8 include alkyl groups, cycloalkyl groups, alkenyl groups, alkyl-substituted cycloalkyl groups, aryl groups, alkyl-substituted aryl groups, and arylalkyl groups. Particularly, R3 to R8 are each preferably an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 24 carbon atoms, more preferably an alkyl group having 3 to 18 carbon atoms, most preferably an alkyl group having 4 to 15 carbon atoms.
- Examples of the phosphorus compounds represented by formula (3) include phosphorous acid monoesters and hydrocarbyl phosphonites, which have one of the above-described hydrocarbon groups having 1 to 30 carbon atoms; phosphorous acid diesters, monothiophosphorous acid diesters and (hydrocarbyl)phosphonous acid monoesters, which have two of the above-described hydrocarbon groups having 1 to 30 carbon atoms; phosphorous acid triesters and (hydrocarbyl)phosphonous acid diesters, which have three of the above-described hydrocarbon groups having 1 to 30 carbon atoms; and mixtures thereof.
- Metal salts or amine salts of the phosphorus compounds represented by formula (3) or (4) can be obtained by allowing, for example, a metal base (e.g., a metal oxide, a metal hydroxide, a metal carbonate, or a metal chloride) or a nitrogen compound (e.g., ammonia, or an amine compound having only a hydrocarbon group or hydroxyl group-containing hydrocarbon group having 1 to 30 carbon atoms in the molecule), to act on a phosphorus compound represented by formula (3) or (4) and subsequently neutralizing some or all of residual acidic hydrogens. Examples of a metal in the above-described metal base include alkali metals, such as lithium, sodium, potassium, and cesium; alkaline earth metals, such as calcium, magnesium, and barium; and heavy metals (excluding molybdenum), such as zinc, copper, iron, lead, nickel, silver, and manganese. Thereamong, alkaline earth metals, such as calcium and magnesium, and zinc are preferable, and zinc is particularly preferable.
- In the lubricant composition, the anti-wear agent is incorporated in an amount of usually 0.1 to 5.0% by weight, preferably 0.2 to 3.0% by weight.
- Examples of the ashless dispersant include nitrogen-containing compounds having at least one linear or branched alkyl or alkenyl group having 40 to 500 carbon atoms, preferably 60 to 350 carbon atoms, in the molecule, and derivatives thereof; Mannich dispersants; mono- or bis-succinimides (e.g., alkenylsuccinimides); benzylamines having at least one alkyl or alkenyl group having 40 to 500 carbon atoms in the molecule; polyamines having at least one alkyl or alkenyl group having 40 to 400 carbon atoms in the molecule; and modified products thereof obtained by modification with a boron compound, carboxylic acid, phosphoric acid or the like. Any one or more of these ashless dispersants can be arbitrarily selected and incorporated. It is particularly preferable that the lubricant composition comprise an alkenylsuccinimide.
- A method of producing the above-described succinimides is not particularly restricted and, for example, and the succinimides can be obtained by allowing a compound having an alkyl or alkenyl group having 40 to 500 carbon atoms to react with maleic anhydride at 100 to 200°C and subsequently allowing the resulting alkyl succinate or alkenyl succinate to react with a polyamine. Examples of the polyamine include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine. Examples of the derivatives of nitrogen-containing compounds exemplified above as the ashless dispersant include compounds modified with a so-called "oxygen-containing organic compound", which are obtained by allowing a monocarboxylic acid having 1 to 30 carbon atoms (e.g., a fatty acid), a polycarboxylic acid having 2 to 30 carbon atoms (e.g., oxalic acid, phthalic acid, trimellitic acid, or pyromellitic acid) or an anhydride thereof, an ester compound thereof, an alkylene oxide having 2 to 6 carbon atoms, or a hydroxy(poly)oxyalkylene carbonate to act on the above-described nitrogen-containing compounds and subsequently neutralizing or amidating some or all of residual amino groups and/or imino groups; so-called "boron-modified compounds", which are obtained by allowing boric acid to act on the above-described nitrogen-containing compounds and subsequently neutralizing or amidating some or all of residual amino groups and/or imino groups; so-called "phosphate-modified compounds", which are obtained by allowing phosphoric acid to act on the above-described nitrogen-containing compounds and subsequently neutralizing or amidating some or all of residual amino groups and/or imino groups; sulfur-modified compounds obtained by allowing a sulfur compound to act on the above-described nitrogen-containing compounds; and modified compounds obtained by performing a combination of two or more types of modifications selected from modification with an oxygen-containing organic compound, boron modification, phosphate modification and sulfur modification on the above-described nitrogen-containing compounds. Among these derivatives, boric acid-modified compounds of alkenylsuccinimides, particularly boric acid-modified compounds of bis-type alkenylsuccinimides, can further improve the heat resistance when used in combination with the above-described base oil.
- The amount of the ashless dispersant is 20% by weight or less, preferably 15% by weight or less, still more preferably 5% by weight or less, based on the total amount of the composition. As the ashless dispersant, a boron-containing ashless dispersant can also be used as a mixture with a boron-free ashless dispersant. When a boron-containing ashless dispersant is used, the content ratio thereof is not particularly restricted; however, it is appropriate that the amount of boron contained in the composition be preferably 0.001 to 0.2% by weight, more preferably 0.003 to 0.1% by weight, most preferably 0.005 to 0.05% by weight, based on the total amount of the composition.
- The number-average molecular weight (Mn) of the ashless dispersant is preferably not less than 2,000, more preferably not less than 2,500, still more preferably not less than 3,000, most preferably not less than 5,000, but preferably not higher than 15,000. When the number-average molecular weight of the ashless dispersant is less than the above-described lower limit value, sufficient dispersibility is not attained in some cases. Meanwhile, when the number-average molecular weight of the ashless dispersant is higher than the above-described upper limit value, an excessively high viscosity makes the fluidity insufficient, causing an increase in deposits.
- Examples of the above-described viscosity index improver include those containing a polymethacrylate, a dispersion-type polymethacrylate, an olefin copolymer (e.g., a polyisobutylene or an ethylene-propylene copolymer), a dispersion-type olefin copolymer, a polyalkylstyrene, a hydrogenated styrene-butadiene copolymer, a styrene-maleic anhydride ester copolymer, a star isoprene or the like. Further, a comb-shaped polymer which contains, in its main chain, at least a repeating unit based on a polyolefin macromer and a repeating unit based on an alkyl (meth)acrylate containing an alkyl group having 1 to 30 carbon atoms, can also be used.
- The viscosity index improver is usually composed of the above-described polymer and a diluent oil. The content of the viscosity index improver is preferably 0.01 to 20% by weight, more preferably 0.02 to 10% by weight, most preferably 0.05 to 5% by weight, in terms of the polymer amount based on the total amount of the composition. When the content of the viscosity index improver is less than the above-described lower limit value, the viscosity-temperature characteristics and the low-temperature viscosity characteristics may be deteriorated. Meanwhile, when the content of the viscosity index improver is higher than the above-described upper limit value, not only the viscosity-temperature characteristics and the low-temperature viscosity characteristics may be deteriorated, but also the production cost is largely increased.
- In the lubricant composition of the present invention, in order to improve the performance thereof, other additive(s) may further be incorporated in accordance with the intended purpose. As other additives, additives that are commonly used in lubricant compositions can be used, and examples thereof include an antioxidant, a friction modifier other than above-described component (B), a corrosion inhibitor, a rust inhibitor, a pour-point depressant, a demulsifier, a metal deactivator, and an anti-foaming agent.
- Examples of the antioxidant include phenolic and amine-based ashless antioxidants, and metal-based antioxidants, such as copper-based and molybdenum-based antioxidants. Examples of the phenolic ashless antioxidants include 4,4'-methylene-bis(2,6-di-tert-butylphenol), 4,4'-bis(2,6-di-tert-butylphenol) and isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, and examples of the amine-based ashless antioxidants include phenyl-α-naphthylamine, alkylphenyl-α-naphthylamine, and dialkyldiphenylamine. The antioxidant is incorporated into the lubricant composition usually in an amount of 0.1 to 5% by weight.
- Examples of the friction modifier other than above-described component (B) include esters, amines, amides, and sulfurized esters. The friction modifier is incorporated into the lubricant composition usually in an amount of 0.01 to 3% by weight.
- Examples of the corrosion inhibitor include benzotriazole-based, tolyltriazole-based, thiadiazole-based, and imidazole-based compounds. Examples of the rust inhibitor include petroleum sulfonates, alkylbenzene sulfonates, dinonylnaphthalene sulfonates, alkenylsuccinic acid esters, and polyhydric alcohol esters. The rust inhibitor and the corrosion inhibitor are each incorporated into the lubricant composition usually in an amount of 0.01 to 5% by weight.
- As the pour-point depressant, for example, a polymethacrylate-based polymer that is compatible with the lubricant base oil to be used can be selected. The pour-point depressant is incorporated into the lubricant composition usually in an amount of 0.01 to 3% by weight.
- Examples of the demulsifier include polyalkylene glycol-based nonionic surfactants, such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, and polyoxyethylene alkylnaphthyl ethers. The demulsifier is incorporated into the lubricant composition usually in an amount of 0.01 to 5% by weight.
- Examples of the metal deactivator include imidazolines, pyrimidine derivatives, alkylthiadiazoles, mercaptobenzothiazoles, benzotriazoles and derivatives thereof, 1,3,4-thiadiazole polysulfides, 1,3,4-thiadiazolyl-2,5-bisdialkyl dithiocarbamates, 2-(alkyldithio)benzimidazoles, and β-(o-carboxybenzylthio)propionitrile. The metal deactivator is incorporated into the lubricant composition usually in an amount of 0.01 to 3% by weight.
- Examples of the anti-foaming agent include silicone oils having a kinematic viscosity at 25°C of 1,000 to 100,000 mm2/s, alkenylsuccinic acid derivatives, esters of a polyhydroxy aliphatic alcohol and a long-chain fatty acid, methyl salicylate, and o-hydroxybenzyl alcohols. The anti-foaming agent is incorporated into the lubricant composition usually in an amount of 0.001 to 1% by weight.
- As other additive, an alkali borate-based additive can be added. The alkali borate-based additive contains an alkali metal borate hydrate and can be represented by the following formula:
M2O·xB2O3·yH2O
- In this formula, M represents an alkali metal; x represents 2.5 to 4.5; and y represents 1.0 to 4.8.
- Specific examples of the alkali borate-based additive include lithium borate hydrate, sodium borate hydrate, potassium borate hydrate, rubidium borate hydrate and cesium borate hydrate, among which potassium borate hydrate and sodium borate hydrate are preferable, and potassium borate hydrate is particularly preferable. The average particle size of these alkali metal borate hydrate particles is generally 1 micron (µ) or smaller. In the alkali metal borate hydrate used in the present invention, the ratio of boron to alkali metal is preferably in a range of about 2.5:1 to 4.5:1. The amount of the alkali borate-based additive to be added is 0.002 to 0.05% by weight in terms of boron amount based on the total amount of the lubricant composition.
- The CCS viscosity at -35°C of the lubricant composition of the present invention is not restricted; however, it is preferably 6.2 Pa·s or less, more preferably 5.0 Pa·s or less, still more preferably 4.0 Pa·s or less, most preferably 3.5 Pa·s or less.
- In the lubricant composition of the present invention, it is preferable that the amount of molybdenum contained therein and the CCS viscosity at -35°C satisfy following equation (5):
- The value of [CCS viscosity]/[B] is more preferably 0.008 or less, still more preferably 0.005 or less. When this value is larger than 0.01, the torque reduction ratio may be reduced and the detergency may be deteriorated. The lower limit value of [CCS viscosity]/[B] is not restricted; however, it is preferably 0.002, more preferably 0.003.
- The high-temperature high-shear viscosity (HTHS viscosity) at 150°C of the lubricant composition of the present invention is not restricted; however, it is preferably 1.7 to 2.9 mPa·s, more preferably 2.0 to 2.6 mPa·s.
- The kinematic viscosity at 100°C of the lubricant composition of the present invention is not restricted; however, it is preferably less than 9.3 mm2/s, more preferably less than 8.2 mm2/s.
- The lubricant composition of the present invention has sufficient friction characteristics and wear characteristics and exerts an effect of attaining a high torque reduction ratio even at a low viscosity; therefore, the lubricant composition of the present invention can be suitably used for internal combustion engines as well as supercharged gasoline engines.
- The present invention will now be described in more detail by way of Examples and Comparative Examples thereof; however, the present invention is not restricted to the below-described Examples.
- Materials used in Examples and Comparative Examples are as follows.
- Lubricant base oil: Fischer-Tropsch-derived base oil, kinematic viscosity at 100°C = 4.1 mm2/s, VI = 127
-
- (A1-1) magnesium salicylate (total base number: 340 mg KOH/g, magnesium content: 7.5% by weight)
- (A1-2) calcium salicylate 1 (total base number: 350 mg KOH/g, calcium content: 12.0% by weight)
- (A1-3) calcium salicylate 2 (total base number: 220 mg KOH/g, calcium content: 8.0% by weight)
-
- (A2-1) magnesium sulfonate (total base number: 400 mg KOH/g, magnesium content: 9.0% by weight)
- (A2-2) calcium sulfonate (total base number: 300 mg KOH/g, calcium content: 11.6% by weight)
- Molybdenum-based friction modifier: MoDTC (a compound represented by above-described formula [1], wherein X1 and X2 are both O, and Y1 and Y2 are both S; molybdenum content: 10% by weight)
-
- Anti-wear agent 1: pri-ZnDTP (primary alkyl group)
- Anti-wear agent 2: sec-ZnDTP (secondary alkyl group)
-
- Antioxidant: phenolic antioxidant
- Ashless dispersant: succinimide
- Viscosity index improver: polymethacrylate
- Anti-foaming agent: dimethyl silicone
- Lubricant compositions were each prepared by mixing the respective components in the amounts indicated in Tables 1 and 3. The amounts of the magnesium-based detergent, calcium-based detergent and molybdenum-based friction modifier indicated in Tables 1 and 3 are concentrations in terms of the contents (ppm by weight) of magnesium, calcium and molybdenum based on the total amount of each lubricant composition ([Mg], [Ca] and [B] in the order mentioned), respectively. The amounts of the anti-wear agent and other additives are in parts by weight based on the total amount (100 parts by weight) of each lubricant composition. It is noted here that the amount of the magnesium-based detergent and that of the calcium-based detergent were controlled such that the total molar amount of magnesium and calcium contained in these detergents was as constant as possible in all of Examples and Comparative Examples. For the thus obtained compositions, the below-described tests were conducted. The results thereof are presented in Tables 2 and 4.
- In Tables 1 and 3 below, [A] represents a total concentration in ppm by weight of all magnesium and calcium contained in each lubricant composition (i.e. including Mg and Ca derived from magnesium sulfonate and calcium sulfonate, respectively), and [A1] represents a total concentration in ppm by weight of magnesium and calcium derived from the metal salicylate(s) (A1) contained in each lubricant composition (i.e. [Ca] + [Mg]). Further, [A1]/[A] represents a ratio (% by weight) of [A1], which is the total concentration in ppm by weight of magnesium and calcium derived from the metal salicylate(s), based on [A], which is the total concentration in ppm by weight of all magnesium and calcium contained in each lubricant composition.
- The high-temperature high-shear viscosity at 150°C was measured in accordance with ASTM D4683.
- The CCS viscosity at -35°C was measured in accordance with ASTM D5293.
- The kinematic viscosity at 100°C was measured in accordance with ASTM D445.
- Using the lubricant compositions obtained in Examples and Comparative Examples as test compositions, the torque was measured in a motoring test with a gasoline engine. A TOYOTA 2ZR-FE 1.8L in-line 4-cylinder engine was used as the engine, and a torque meter was arranged between a motor and the engine to measure the torque at an oil temperature of 80°C and an engine speed of 700 rpm. The torque was also measured in the same manner using a commercially available GF-5 0W-20 oil as a standard oil. The torque (T) of each test composition was compared with the torque (T0) of the standard oil, and the reduction ratio from the torque of the standard oil, ({(T0 - T)/T0} × 100) (%), was calculated. A higher reduction ratio indicates superior fuel efficiency. A reduction ratio of 5.5% or higher was regarded as satisfactory.
- The diameter of shell wear scar was measured in accordance with the shell four-ball test (ASTM D4172), except that the rotation speed, the load, the testing temperature and the testing time were set at 1,800 rpm, 40 kgf, 90°C and 30 minutes, respectively. A wear scar diameter of 0.7 mm or smaller was regarded as satisfactory.
- Each lubricant composition and air were allowed to continuously flow in a glass tube of 2 mm in inner diameter for 16 hours at rates of 0.3 mL/hr and 10 mL/sec, respectively, while maintaining the temperature of the glass tube at 270°C. A lacquer adhered to the glass tube was compared with a color chart and evaluated with a score of 10 when the lacquer was transparent or a score of 0 when the lacquer was black. A higher score indicates superior high-temperature detergency. A score of 5.0 or higher was regarded as satisfactory.
[Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 Lubricant base oil balance balance balance balance balance balance balance balance balance balance balance balance (A1-1) magnesium salicylate ([Mg], ppm by weight) 300 600 300 0 300 1,100 300 0 900 600 600 1,500 (A2-1) magnesium sulfonate ([Mg], ppm by weight) 0 0 0 300 0 0 0 300 0 0 0 0 (A1-2) calcium salicylate 1 ([Ca], ppm by weight) 1,400 900 1,400 1,400 0 0 1,400 1,400 500 0 1,400 1,300 (A1-3) calcium salicylate 2 ([Ca], ppm by weight) 0 0 0 0 1,400 0 0 0 0 0 0 0 (A2-2) calcium sulfonate ([Ca], ppm by weight) 0 0 0 0 0 0 0 0 0 900 0 0 [A1] total ([Ca] + [Mg]) 1,700 1,500 1,700 1,400 1,700 1,100 1,700 1,400 1,400 600 2,000 2,800 [A1]/[A] (% by weight) 100 100 100 82 100 100 100 82 100 40 100 100 (B) molybdenum-based friction modifier 700 700 700 700 700 1,000 1,000 1,000 700 700 700 700 Anti-wear agent 1 1 1 - - - 1 - - 1 1 1 1 Anti-wear agent 2 - - 1 1 1 - 1 1 - - - - Antioxidant 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 Ash-free dispersant 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 Viscosity index improver 8.7 8.7 8.7 8.7 8.7 8.7 8.7 8.7 8.7 8.7 8.7 8.7 Anti-foaming agent 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 [A]/[B] 2.4 2.1 2.4 2.4 2.4 1.1 1.7 1.7 2.0 2.1 2.9 4.0 [A1]/[B] 2.4 2.1 2.4 2.0 2.4 1.1 1.7 1.4 2.0 0.9 2.9 4.0 [Table 2] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 Evaluation results KV100 mm2/s 6.8 6.7 6.8 6.8 6.7 6.6 6.9 6.9 6.6 6.6 6.7 6.9 HTHS 150 MPa·s 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.4 2.4 CCS viscosity Pa·s 3.2 3.1 3.4 3.3 3.3 3.4 3.4 3.4 3.1 3.0 3.1 3.2 Torque reduction ratio % 5.99 7.71 8.04 6.40 7.40 7.43 7.45 8.66 7.50 7.29 7.40 6.90 Diameter of shell wear scar mm 0.64 0.63 0.68 0.55 0.62 0.61 0.66 0.66 0.63 0.52 0.61 0.61 Hot tube 270°C 7.5 7.5 6.5 5.5 5.5 8.5 5.5 5.5 7.5 6.0 5.5 8.0 [CCS viscosity]/[B] 0.0046 0.0044 0.0049 0.0047 0.0047 0.0034 0.0034 0.0034 0.0044 0.0043 0.0044 0.0046 [Table 3] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Lubricant base oil balance balance balance balance balance balance balance balance (A1-1) magnesium salicylate ([Mg], ppm by weight) 0 0 0 300 600 1,900 0 0 (A2-1) magnesium sulfonate ([Mg], ppm by weight) 0 0 0 0 0 0 600 0 (A1-2) calcium salicylate 1 ([Ca], ppm by weight) 1,900 1,900 1,900 1,400 900 0 0 0 (A1-3) calcium salicylate 2 ([Ca], ppm by weight) 0 0 0 0 0 0 0 0 (A2-2) calcium sulfonate ([Ca], ppm by weight) 0 0 0 0 0 0 900 1,700 [A1] total ([Ca] + [Mg]) 1,900 1,900 1,900 1,700 1,500 1,900 0 0 [A1]]/[A] (% by weight) 100 100 100 100 100 100 0 0 (B) molybdenum-based friction modifier 700 1,000 1,000 300 300 700 700 700 Anti-wear agent 1 1 1 - 1 1 1 1 1 Anti-wear agent 2 - - 1 - - - - - Antioxidant 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 Ash-free dispersant 3.6 3.6 3.6 3.6 3.6 3.6 3.6 3.6 Viscosity index improver 8.7 8.7 8.7 8.7 8.7 8.7 8.7 8.7 Anti-foaming agent 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0-1 [A]/[B] 2.7 1.9 1.9 5-7 5.0 2-7 2-1 2.4 [A1]/[B] 2-7 1.9 1.9 5.7 5.0 2.7 0.0 0.0 [Table 4] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Evaluation results KV100 mm2/s 6.8 6.9 6.9 6.7 6.8 6.8 6.4 6.5 HTHS 150 MPa·s 2.3 2.3 2.3 2.3 2.3 2.4 2.3 2.3 CCS viscosity Pa·s 3.2 3.4 3.4 3.3 3.3 3.2 3.0 3.0 Torque reduction ratio % 0.86 2.91 5.30 1.70 3.40 6.00 4.50 4.20 Diameter of shell wear scar mm 0.53 0.63 0.61 0.54 0.62 0.81 0.63 0.60 Hot tube 270°C 6.5 6.5 4.0 3.0 4.0 9.0 1.0 1.0 [CCS viscosity]/[B] 0.0046 0.0034 0.0034 0.0110 0.0110 0.0046 0.0043 0.0043 - As indicated in Table 4, the compositions of Comparative Examples 1 to 3 in which the content of calcium salicylate (A1) was high had a low torque reduction ratio, and the composition of Comparative Example 6 containing a large amount of magnesium salicylate (A) caused a large wear. Further, the compositions of Comparative Examples 4 and 5 in which the amount of the molybdenum-based friction modifier (B) was less than the lower limit of the present invention had a low torque reduction ratio and exhibited poor high-temperature detergency. Moreover, the compositions of Comparative Examples 7 and 8 which did not contain any metal salicylate not only had a low torque reduction ratio but also exhibited poor high-temperature detergency.
- On the other hand, as indicated in Table 2, the lubricant compositions according to the present invention caused only a small wear and exhibited a high torque reduction ratio and excellent high-temperature detergency, despite having a low kinematic viscosity at 100°C.
Claims (10)
- A lubricant composition comprising:a lubricant base oil;(A1) a metal salicylate; and(B) a molybdenum-based friction modifier, whereinthe amount of component (B) is in a range of 500 to 1,500 ppm by weight in terms of a concentration [B] in ppm by weight of molybdenum in the lubricant composition, component (A1) is any one of calcium salicylate, magnesium salicylate, and a combination thereof,the amount of calcium salicylate is 0 to 1,800 ppm by weight in terms of a concentration [Ca] in ppm by weight of calcium derived from calcium salicylate in the lubricant composition,the amount of magnesium salicylate is 0 to 1,800 ppm by weight in terms of a concentration [Mg] in ppm by weight of magnesium derived from magnesium salicylate in the lubricant composition, anda total of [Ca] and [Mg] is in a range of 200 to 3,000 ppm by weight.
- The lubricant composition according to claim 1, which optionally further comprises a metallic detergent other than component (A1) as a metallic detergent (A),
wherein the weight of component (A1) based on the total weight of the metallic detergent (A) is in a range of 5 to 100% by weight in terms of a ratio of [Ca] and [Mg] based on a total concentration [A] in ppm by weight of metals derived from the metallic detergent in the lubricant composition. - The lubricant composition according to claim 1 or 2, wherein the metal salicylate (A1) is a combination of magnesium salicylate and calcium salicylate.
- The lubricant composition according to claim 1 or 2, wherein the metal salicylate (A1) is at least one kind of magnesium salicylate.
- The lubricant composition according to any one of claims 1 to 4, wherein
the lubricant composition further comprises (A2) a metallic detergent other than component (A1) as the metallic detergent (A),
component (A2) comprises at least one selected from magnesium, calcium and sodium, and
the amount of the metallic detergent (A) satisfies following equation (1):
wherein [A] represents a total concentration in ppm by weight of magnesium, calcium and sodium in the lubricant composition. - The lubricant composition according to any one of claims 1 to 5, wherein the amount of the metal salicylate (A1) satisfies following equation (2):
- The lubricant composition according to any one of claims 1 to 6, which has a CCS viscosity at -35°C of 6.2 Pa·s or less.
- The lubricant composition according to any one of claims 1 to 7, which has a high-temperature high-shear viscosity (HTHS viscosity) at 150°C of 1.7 to 2.9 mPa·s.
- The lubricant composition according to any one of claims 1 to 8, which has a kinematic viscosity at 100°C of less than 9.3 mm2/s.
- The lubricant composition according to any one of claims 1 to 9, which is for an internal combustion engine.
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PCT/JP2017/027544 WO2018021559A1 (en) | 2016-07-29 | 2017-07-28 | Lubricant composition |
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CN114317072A (en) * | 2020-09-29 | 2022-04-12 | 惠州金永信五金制品有限公司 | Lubricant suitable for metal stamping |
JP2022180775A (en) * | 2021-05-25 | 2022-12-07 | Eneos株式会社 | Lubricant composition for internal combustion engine |
JP2022180774A (en) * | 2021-05-25 | 2022-12-07 | Eneos株式会社 | Lubricant composition for internal combustion engine |
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US5906968A (en) | 1997-12-12 | 1999-05-25 | Exxon Research & Engineering Company | Method of synthesizing Mo3 Sx containing compounds |
US5906969A (en) * | 1998-05-01 | 1999-05-25 | Exxon Research And Engineering Company | High fuel economy passenger car engine oil |
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