JP2016190918A - Lubricant composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lubricant composition excellent in all of abrasion resistance, seizure resistance and fuel saving property.SOLUTION: There is provided a lubricant composition having a dynamic viscosity at 100°C of 2.0 mm/s or more and 5.0 mm/s or less which comprises a lubricant base oil, a copolymer of an ester monomer having a polymerizable unsaturated bond and an α-olefin and a performance additive including phosphorus, sulfur and boron as a constituent element, where the lubricant base oil contains a first component having a dynamic viscosity at 100°C of 1.0 mm/s or more and 3.0 mm/s or less and a second component composed of a poly α-olefin having a dynamic viscosity at 100°C of 200 mm/s, the content of each performance additive satisfies the expressions (1), (2) and (3): C≤0.10 (1), C≥0.07 (2) and 0.5≤C/C≤6.0 (3) [C, Cand Crepresent the value expressed in terms of the elements of phosphorus, sulfur and boron, respectively].SELECTED DRAWING: None

Description

  The present invention relates to a lubricating oil composition.

  In recent years, there has been an urgent need to save energy in automobiles, construction machinery, agricultural machinery, etc., that is, to save fuel, in response to environmental issues such as reducing carbon dioxide emissions. Engines, transmissions, final reduction gears, compression Devices such as machines and hydraulic devices are strongly required to contribute to energy saving. Therefore, the lubricating oil used in these is required to further reduce the stirring resistance and the rotational resistance as compared with the conventional one.

  One way to save fuel is to reduce the viscosity of the lubricating oil. For example, among automatic transmissions, automatic transmissions for automobiles and continuously variable transmissions have torque converters, wet clutches, gear bearing mechanisms, oil pumps, hydraulic control mechanisms, etc., and manual transmissions and final reduction gears are gear bearings. By reducing the viscosity of the lubricating oil used in these mechanisms, the stirring resistance and rotational resistance of torque converters, wet clutches, gear bearing mechanisms, oil pumps, etc. are reduced, and power transmission efficiency is improved. By improving, it becomes possible to improve the fuel consumption of the automobile.

  However, if the viscosity of the base oil is lowered and a large amount of viscosity index improver is blended to reduce the viscosity of the lubricating oil, extreme pressure and wear resistance are reduced due to a decrease in the oil film thickness, which is a contradiction. In some cases, seizure or the like may occur and the transmission or the like may malfunction.

  Conventionally, as a lubricating oil composition having both fuel saving performance and sufficient durability such as gears and bearings, a lubricating oil composition in which various additives are blended with a mineral base oil and / or a synthetic base oil base oil. Although proposed (for example, refer to Patent Documents 1 and 2), there is room for improvement in fuel efficiency even in such a lubricating oil composition.

JP 2002-003875 A JP 2012-193255 A

  This invention is made | formed in view of such a situation, and it aims at providing the lubricating oil composition excellent in all of abrasion resistance, seizure resistance, and fuel-saving property.

The present invention comprises a lubricant base oil, a copolymer of an ester monomer having a polymerizable unsaturated bond and an α-olefin, and a performance additive containing phosphorus, sulfur and boron as constituent elements. The lubricant base oil has a kinematic viscosity at 100 ° C. of 1.0 mm ² / s to 3.0 mm ² / s and a first lubricant base oil component having a kinematic viscosity at 100 ° C. of 200 mm ² / s or more. A second lubricating base oil component comprising a poly-α-olefin, and the content of the performance additive is represented by the following formulas (1), (2) and (3):
C _P ≦ 0.10 (1)
C _S ≧ 0.07 (2)
0.5 ≦ C _P / C _B ≦ 6.0 (3)
[Wherein, C _P , C _S and C _B represent element conversion values (mass%) of phosphorus, sulfur and boron, respectively, of the performance additive content based on the total amount of the lubricating oil composition. ]
And a kinematic viscosity at 100 ° C. is 2.0 mm ² / s to 5.0 mm ² / s.

  The performance additive includes a first additive that contains phosphorus as a constituent element and does not contain sulfur and boron, a second additive that contains sulfur as a constituent element and does not contain phosphorus and boron, and a phosphorus additive that contains boron as a constituent element. And a third additive not containing sulfur.

  The content of the second lubricating base oil component is preferably 0.5% by mass or more and 50% by mass or less based on the total amount of the lubricating oil composition.

  The content of the copolymer is preferably 1.0% by mass or more and 10.0% by mass or less based on the total amount of the lubricating oil composition.

  The above lubricating oil composition is suitable as a lubricating oil composition for automatic transmissions or continuously variable transmissions.

  ADVANTAGE OF THE INVENTION According to this invention, the lubricating oil composition excellent in all of abrasion resistance, seizure resistance, and fuel-saving property can be provided.

  Hereinafter, embodiments of the present invention will be described in detail.

  The lubricating oil composition according to the present embodiment includes a lubricating base oil, a copolymer of an ester monomer having a polymerizable unsaturated bond, and an α-olefin, and a performance containing phosphorus, sulfur, and boron as constituent elements. And an additive.

The lubricant base oil has a first lubricant base oil component having a kinematic viscosity at 100 ° C. of 1.0 mm ² / s to 3.0 mm ² / s and a kinematic viscosity at 100 ° C. of 200 mm ² / s or more. And a second lubricating base oil component made of a certain poly α-olefin.

  Examples of the first lubricating base oil component include a mineral base oil, a synthetic base oil, or a mixture of both.

  As mineral base oils, lubricating oil fractions obtained by subjecting crude oil to atmospheric distillation and reduced pressure distillation are subjected to solvent deburring, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrorefining, sulfuric acid Examples include paraffinic and naphthenic mineral oil base oils, normal paraffins, isoparaffins, and the like, which are purified by combining purification treatments such as washing and clay treatment alone or in combination of two or more. These mineral oil base oils may be used singly or in combination of two or more at any ratio.

Preferred mineral base oils include the following base oils.
(1) Distilled oil obtained by atmospheric distillation of paraffin-based crude oil and / or mixed-base crude oil (2) Vacuum-distilled distilled oil (WVGO) of atmospheric distillation residue oil of paraffin-based crude oil and / or mixed-base crude oil )
(3) Wax obtained by a lubricant dewaxing step and / or a Fischer-Tropsch wax produced by a GTL process or the like (4) One or more mixed oils selected from the above (1) to (3) Mild hydrocracking oil (MHC)
(5) Mixed oil of two or more oils selected from the above (1) to (4) (6) Detachment of (1), (2), (3), (4) or (5) Oil (DAO)
(7) Mild hydrocracking treatment oil (MHC) of (6) above
(8) A mixed oil or the like of two or more kinds of oils selected from the above (1) to (7) is used as a raw oil, and this raw oil and / or a lubricating oil fraction recovered from this raw oil is usually used. Oil obtained by refining by the refining method and recovering the lubricating oil fraction

Here, the normal refining method is not particularly limited, and a refining method used in base oil production can be arbitrarily employed. Examples of normal purification methods include the following purification methods.
(A) Hydrorefining such as hydrocracking, hydrofinishing, etc. (b) Solvent refining such as extraction of furfural solvent (c) Dewaxing such as solvent dewaxing, catalytic dewaxing, etc. (d) White clay with acid clay, activated clay Purification (e) Chemical (acid or alkali) purification such as sulfuric acid washing and caustic soda washing These purification methods can be used singly or in combination of two or more and in any order.

  The sulfur content (also referred to as sulfur content) of the mineral oil base oil is not particularly limited, but may be 100 ppm by mass, 50 ppm by mass or 10 ppm by mass based on the total amount of the lubricant base oil. The sulfur content of the mineral base oil can be determined by, for example, ICP elemental analysis.

  Synthetic base oils include poly α-olefins or hydrides thereof, isobutene oligomers or hydrides thereof, isoparaffins, alkylbenzenes, alkylnaphthalenes, diesters (ditridecyl glutarate, di-2-ethylhexyl adipate, di-2-ethylhexyl azease). Rate, diisodecyl adipate, ditridecyl adipate, di-2-ethylhexyl sebacate, etc.), polyol ester (trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol 2-ethylhexanoate, pentaerythritol pelargonate, etc.), Polyoxyalkylene glycol, dialkyl diphenyl ether, polyphenyl ether and the like can be mentioned, among which poly α-olefin is preferable. Examples of the poly α-olefin include oligomers or co-oligomers (1-octene oligomer, decene oligomer, ethylene-propylene co-oligomer, etc.) of α-olefin having 2 to 32 carbon atoms, preferably 6 to 16 carbon atoms, and those. A hydride is mentioned. These synthetic base oils may be used individually by 1 type, and may be used combining 2 or more types by arbitrary ratios.

The kinematic viscosity at 40 ° C. of the first lubricating base oil component is preferably 3 mm ² / s or more, more preferably 5 mm ² / s or more, and further preferably 7 mm ² / s or more. When the kinematic viscosity at 40 ° C. is 3 mm ² / s or more, the formation of an oil film is sufficient, and it is easy to obtain a lubricating oil composition that is excellent in lubricity and has a smaller evaporation loss under high temperature conditions. The kinematic viscosity at 40 ° C. of the first lubricating base oil component is preferably 15 mm ² / s or less, more preferably 12 mm ² / s or less, and still more preferably 10 mm ² / s or less. When the kinematic viscosity at 40 ° C. is 15 mm ² / s or less, the fluid resistance becomes small, so that it becomes easy to obtain a lubricating oil composition having a smaller rotational resistance.

The kinematic viscosity at 100 ° C. of the first lubricating base oil component is preferably 1.0 mm ² / s or more, more preferably 1.5 mm ² / s or more, and further preferably 2.0 mm ² / s or more. When the kinematic viscosity at 100 ° C. is 1.0 mm ² / s or more, the formation of an oil film is sufficient, and it is easy to obtain a lubricating oil composition that is superior in lubricity and has a smaller evaporation loss under high temperature conditions. Kinematic viscosity at 100 ° C. of the first lubricating base oil component is preferably 3.0 mm ² / s or less, more preferably 2.8 mm ² / s or less, more preferably 2.6 mm ² / s or less. When the kinematic viscosity at 100 ° C. is 3.0 mm ² / s or less, the fluid resistance becomes small, so that it becomes easy to obtain a lubricating oil composition having a smaller rotational resistance.

  The viscosity index of the first lubricating base oil component is preferably 85 or higher, more preferably 90 or higher, and still more preferably 95 or higher. When the viscosity index is 85 or more, it becomes easy to obtain a lubricating oil composition exhibiting better viscosity characteristics from low temperature to high temperature. The viscosity index of the first lubricating base oil component may be, for example, 85 or less.

  The kinematic viscosity and viscosity index in the present invention mean kinematic viscosity and viscosity index measured in accordance with JIS K2283: 2000, respectively.

  The pour point of the first lubricating base oil component is preferably −35 ° C. or lower, more preferably −37.5 ° C. or lower, and further preferably −40 ° C. or lower, from the viewpoint of excellent low temperature fluidity. The pour point in the present invention means a pour point measured according to JIS K2269-1987.

  The flash point of the first lubricating base oil component is preferably 140 ° C. or higher, more preferably 150 ° C. or higher, and still more preferably 160 ° C. or higher, from the viewpoint of excellent safety. The flash point in the present invention means a flash point measured according to JIS K2265-4: 2007.

  The content of the first lubricating base oil component is preferably 50% by mass or more, more preferably 75% by mass or more, and still more preferably 95% by mass, based on the total amount of the lubricating oil composition, from the viewpoint of excellent fuel economy. % Or more. The content of the first lubricating base oil component may be, for example, 95% by mass or less, 75% by mass or less, or 50% by mass or less based on the total amount of the lubricating oil composition.

The second lubricating base oil component is composed of at least one poly α-olefin having a kinematic viscosity at 100 ° C. of 200 mm ² / s or more. Examples of such poly α-olefins include oligomers or co-oligomers of 2 to 32 carbon atoms, preferably 6 to 16 carbon atoms, and hydrides thereof. The α-olefin is preferably 1-octene, 1-decene, 1-dodecene and the like, and the co-oligomer is exemplified by ethylene-propylene co-oligomer and the like.

The kinematic viscosity at 40 ° C. of the second lubricating base oil component is preferably 1000 mm ² / s or more, more preferably 1500 mm ² / s or more, and still more preferably 2000 mm ² / s or more. When the kinematic viscosity at 40 ° C. is 1000 mm ² / s or more, the formation of an oil film is sufficient, and it is easy to obtain a lubricating oil composition that is excellent in lubricity and has a smaller evaporation loss under high temperature conditions. The kinematic viscosity at 40 ° C. of the second lubricating base oil component is preferably 5000 mm ² / s or less, more preferably 4500 mm ² / s or less, and still more preferably 4000 mm ² / s or less. When the kinematic viscosity at 40 ° C. is 5000 mm ² / s or less, the fluid resistance becomes small, so that it becomes easy to obtain a lubricating oil composition having a smaller rotational resistance.

The kinematic viscosity at 100 ° C. of the second lubricating base oil component is preferably 200 mm ² / s or more, more preferably 250 mm ² / s or more, and even more preferably 300 mm ² / s or more. When the kinematic viscosity at 100 ° C. is 200 mm ² / s or more, the formation of an oil film is sufficient, and it is easy to obtain a lubricating oil composition that is excellent in lubricity and has a smaller evaporation loss under high temperature conditions. The kinematic viscosity at 100 ° C. of the second lubricating base oil component is preferably 1000 mm ² / s or less, more preferably 750 mm ² / s or less, and still more preferably 500 mm ² / s or less. When the kinematic viscosity at 100 ° C. is 1000 mm ² / s or less, the fluid resistance becomes small, so that it becomes easy to obtain a lubricating oil composition having a smaller rotational resistance.

  The viscosity index of the second lubricating base oil component is preferably 150 or more, more preferably 175 or more, and still more preferably 200 or more. When the viscosity index is 150 or more, it becomes easy to obtain a lubricating oil composition exhibiting better viscosity characteristics from low temperature to high temperature. The viscosity index of the second lubricating base oil component is preferably 350 or less. When the viscosity index is 350 or less, solubility with the first lubricating base oil component can be secured.

  The content of the second lubricating base oil component is preferably 0.5% by mass or more, more preferably 5% by mass or more, based on the total amount of the lubricating oil composition, from the viewpoint of excellent wear resistance and seizure resistance. More preferably, it is 10% by mass or more. The content of the second lubricating base oil component is preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass, based on the total amount of the lubricating oil composition, from the viewpoint of excellent fuel economy. % Or less.

  The pour point of the second lubricating base oil component is preferably −10 ° C. or lower, more preferably −15 ° C. or lower, and further preferably −20 ° C. or lower, from the viewpoint of excellent low temperature fluidity.

  The flash point of the second lubricating base oil component is preferably 150 ° C. or higher, more preferably 175 ° C. or higher, and further preferably 200 ° C. or higher, from the viewpoint of excellent lubricity.

  A copolymer of an ester monomer having a polymerizable unsaturated bond and an α-olefin (hereinafter also simply referred to as “copolymer”) is used as a viscosity modifier.

  The ester monomer having a polymerizable unsaturated bond is not particularly limited as long as it is a compound having a polymerizable unsaturated bond and an ester bond, and is preferably an α, β-ethylenically unsaturated dicarboxylic acid diester. The α, β-ethylenically unsaturated dicarboxylic acid diester is an unsaturated dicarboxylic acid in which the α and β carbons of at least one carboxy group form an ethylenically unsaturated bond (ie, a carbon-carbon double bond). It is a diester form. The α, β-ethylenically unsaturated dicarboxylic acid has an ethylenically unsaturated bond between the α and β carbons of both carboxy groups, such as maleic acid, fumaric acid, citraconic acid, and mesaconic acid. And an α, β-ethylenically unsaturated bond may be present in the main chain. Alternatively, the α, β-ethylenically unsaturated dicarboxylic acid may be a compound in which the α carbon and the β carbon form an ethylenically unsaturated bond for only one carboxy group, such as glutaconic acid. And a compound having an α, β-ethylenically unsaturated bond in the side chain, such as itaconic acid.

  The α-olefin is not particularly limited, but is preferably an α-olefin having 12 to 18 carbon atoms, more preferably 14 to 16 carbon atoms. The α-olefin may be linear or branched. By using such an α-olefin, a copolymer having good compatibility with the nonpolar base oil can be obtained.

  Examples of the α-olefin include 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and the like. These may be used alone or in combination of two or more.

  The structure and production method of the copolymer are not particularly limited, and may be a known structure and production method, respectively.

  The weight average molecular weight of the copolymer is preferably 9000 or more, more preferably 10,000 or more, and still more preferably 11000 or more. The weight average molecular weight of the copolymer is preferably 15000 or less, more preferably 14000 or less, and still more preferably 13000 or less. When the weight average molecular weight of the copolymer is 9000 or more or 15000 or less, it becomes easy to obtain a lubricating oil composition exhibiting good low temperature fluidity.

  The weight average molecular weight in this invention means the weight average molecular weight of standard polystyrene conversion measured by GPC. The weight average molecular weight in the present invention is such that, for example, two columns of Tosoh GMHHR-M (7.8 mm ID × 30 cm) are used in series in a Waters 150-C ALC / GPC apparatus, and tetrahydrofuran is used as a solvent. , At a temperature of 23 ° C., a flow rate of 1 mL / min, a sample concentration of 1% by mass, and a sample injection amount of 75 μL, and measured as a weight average molecular weight in terms of standard polystyrene using a differential refractometer (RI) detector.

  The content of the copolymer is preferably 1.0% by mass or more, more preferably 3.0% by mass or more, based on the total amount of the lubricating oil composition, from the viewpoint of further excellent wear resistance and seizure resistance. Preferably it is 5.0 mass% or more. The content of the copolymer is preferably 10.0% by mass or less, more preferably 8% by mass or less, and still more preferably 6%, based on the total amount of the lubricating oil composition, from the viewpoint of excellent wear resistance and seizure resistance. It is below mass%.

  The performance additive containing phosphorus, sulfur, and boron as constituent elements includes a first additive that contains phosphorus as constituent elements and does not contain sulfur and boron, and a second additive that contains sulfur as constituent elements and does not contain phosphorus and boron. An additive and a third additive which contains boron as a constituent element and does not contain phosphorus and sulfur may be contained. The performance additive is a performance obtained by appropriately combining an additive containing two kinds selected from phosphorus, sulfur, and boron as constituent elements and the first additive, the second additive, or the third additive. It may be an additive. As such a combination, for example, a combination of a fourth additive containing phosphorus and sulfur as constituent elements and not containing boron and a third additive may be mentioned.

  Examples of the first additive include phosphorous esters (phosphites), phosphate esters, and phosphorus extreme pressure agents such as amine salts, metal salts, and derivatives thereof.

  Second additives include sulfur-based extreme pressure agents such as dithiocarbamate, zinc dithiocarbamate, molybdenum dithiocarbamate (MoDTC), disulfide, polysulfide, sulfurized olefin, sulfurized oil and fat, sulfonate detergent (alkali metal or alkaline earth) Sulfur-metal detergents such as normal salts with base metals, basic normal salts, overbased salts), mercaptobenzothiazole, 2- (alkyldithio) benzimidazole, β- (o-carboxybenzylthio) propiononitrile, etc. Sulfur-based metal deactivators, sulfur-based corrosion inhibitors such as thiadiazole compounds, and sulfur-based rust inhibitors such as petroleum sulfonate, alkylbenzene sulfonate, and dinonylnaphthalene sulfonate.

  Examples of the third additive include boron-containing succinimide, boric acid ester, and alkali metal salt of boric acid.

  Examples of the boron-containing succinimide include boric acid-modified succinimides of alkyl or alkenyl succinimides having an alkyl group or alkenyl group having 40 to 400 carbon atoms. The boric acid-modified succinimide is, for example, polyamine, polyalkyl (alkenyl) succinic acid (anhydride), boric acid, boric acid ester, borate, etc. in a solvent such as alcohol, hexane, xylene, and light oil. It can be obtained by mixing with a boron compound and heat-treating under appropriate conditions.

  Examples of the fourth additive include zinc dialkyldithiophosphate (ZnDTP), thiophosphite ester, dithiophosphite ester, trithiophosphite ester, thiophosphate ester, dithiophosphate ester, trithiophosphate ester, and these And sulfur-phosphorus extreme pressure agents such as amine salts, ammonium salts, metal salts, and derivatives thereof.

The content of the performance additive containing phosphorus, sulfur, and boron as constituent elements preferably satisfies the conditions represented by the following formulas (1), (2), and (3).
C _P ≦ 0.10 (1)
C _S ≧ 0.07 (2)
0.5 ≦ C _P / C _B ≦ 6.0 (3)
[Wherein, C _P , C _S and C _B represent element conversion values (mass%) of phosphorus, sulfur and boron in the content of the performance additive based on the total amount of the lubricating oil composition, respectively. ]

CP is preferably 0.10 or less, more preferably 0.08 or less, and further 0.06 or less from the viewpoint of excellent wear resistance and seizure resistance under high load conditions (for example, about 800 _N ). C _P is, from the viewpoint of excellent abrasion resistance and seizing resistance, it is preferably 0.02 or more, more preferably 0.03 or more, more preferably 0.04 or more. C _P is, for example, the phosphorus element content in the lubricating oil composition may be determined by ICP elemental analysis and the like, or analyzed in advance by ICP elemental analysis and the like phosphorus content in the performance additives, the You may calculate from the preparation amount (content) of the performance additive containing phosphorus as an analysis value and a structural element.

C _S, from the viewpoint of excellent wear resistance and seizure resistance is preferably 0.07 or more, more preferably 0.10 or more, more preferably 0.12 or more. C _S, from the viewpoint of excellent wear resistance and seizure resistance, preferably 0.30 or less, more preferably 0.25 or less, more preferably 0.20 or less. C _S, for example, elemental sulfur content of the lubricating oil composition may be determined by ICP elemental analysis and the like, or analyzed in advance by ICP elemental analysis and the like elemental sulfur content of performance additives, You may calculate from the preparation amount (content) of the performance additive containing the analysis value and sulfur as a structural element.

C _B, from the viewpoint of excellent wear resistance and seizure resistance, is preferably 0.005 or more, more preferably 0.01 or more, more preferably 0.02 or more. C _B, from the viewpoint of excellent wear resistance and seizure resistance, preferably 0.09 or less, more preferably 0.08 or less, more preferably 0.07 or less. C _B, for example, a boron element content of the lubricating oil composition may be determined by ICP elemental analysis and the like, or analyzed in advance by ICP elemental analysis and the like of boron element content of performance additives, You may calculate from the analytical value and the preparation amount (content) of the performance additive which contains boron as a structural element.

C _P / C _B is preferably 0.5 or more, more preferably 1.0 or more, still more preferably 1. from the viewpoint of excellent wear resistance and seizure resistance under high load conditions (for example, about 800 _N ). 5 or more. C _P / C _B is preferably 6.0 or less, more preferably 5.0 or less, and still more preferably 4.0 or less, from the viewpoint of excellent wear resistance.

  The content of the performance additive containing phosphorus, sulfur, and boron as constituent elements is, for example, 5.0% by mass or more, 6.0% by mass or more, or 7.0% by mass or more based on the total amount of the lubricating oil composition. For example, it may be 10.0% by mass or less, 9.0% by mass or less, or 8.0% by mass or less.

  The lubricating oil composition may further contain other additives in addition to the above performance additives. Other additives include, for example, friction modifiers, viscosity modifiers, metal detergents, ashless dispersants, antioxidants, corrosion inhibitors, rust inhibitors, antiemulsifiers, metal deactivators, and antifoaming agents. Etc.

  Examples of friction modifiers include ashless friction modifiers. Examples of the ashless friction modifier include compounds having 6 to 50 carbon atoms and having at least one heteroatom selected from an oxygen atom and a nitrogen atom in the molecule. As a further specific example of the ashless friction modifier, at least one alkyl group or alkenyl group having 6 to 30 carbon atoms, particularly a linear or branched alkyl group or alkenyl group having 6 to 30 carbon atoms in the molecule. Examples thereof include amine compounds, fatty acid esters, fatty acid amides, fatty acids, aliphatic alcohols, aliphatic ethers, urea compounds, and hydrazide compounds.

  The viscosity modifier is a viscosity modifier other than a copolymer of an α-olefin and an ester monomer having a polymerizable unsaturated bond. Examples of the viscosity modifier include a non-dispersed or dispersed poly (meth) acrylate viscosity modifier and a styrene-maleic anhydride copolymer viscosity modifier. Among these, the viscosity modifier is preferably a non-dispersed or dispersed poly (meth) acrylate viscosity modifier, and more preferably a non-dispersed or dispersed polymethacrylate viscosity modifier. Other examples of the viscosity modifier include a non-dispersed or dispersed ethylene-α-olefin copolymer or a hydride thereof, polyisobutylene or a hydride thereof, a styrene-diene hydrogenated copolymer, and a polyalkylstyrene. be able to.

  Examples of metal detergents include salicylate detergents and phenate detergents. These metal detergents may be any of normal salt, basic normal salt, and overbased salt with alkali metal or alkaline earth metal.

  Examples of the ashless dispersant include mono- or bissuccinimide having at least one linear or branched alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule, and an alkyl group having 40 to 400 carbon atoms. Or benzylamine having at least one alkenyl group in the molecule, polyamines having at least one alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule, and modified products of these by carboxylic acid, etc. .

  Examples of the antioxidant include ashless antioxidants such as phenols and amines, and metal antioxidants such as copper and molybdenum. Specifically, for example, as a phenol-based ashless antioxidant, 4,4′-methylenebis (2,6-di-tert-butylphenol), 4,4′-bis (2,6-di-tert- Butylphenol) and the like are amine-based ashless antioxidants such as phenyl-α-naphthylamine, alkylphenyl-α-naphthylamine, dialkyldiphenylamine, and diphenylamine.

  Examples of the corrosion inhibitor include benzotriazole, tolyltriazole, and imidazole compounds.

  Examples of the rust preventive include alkenyl succinic acid ester and polyhydric alcohol ester.

  Examples of the demulsifier include polyalkylene glycol nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, and polyoxyethylene alkyl naphthyl ether.

  Examples of the metal deactivator include imidazoline, pyrimidine derivatives, benzotriazole or derivatives thereof.

As the defoaming agent, for example, 100,000 mm kinematic viscosity at 25 ° C. is 1000 mm ² / s or more ² / s or less silicone oil, alkenylsuccinic acid derivatives, esters of polyhydroxy aliphatic alcohols and long-chain fatty acids, methyl salicylate And esters of o-hydroxybenzyl alcohol and the like.

  The content of other additives may be 0.01 to 20% by mass based on the total amount of the lubricating oil composition.

The kinematic viscosity at 40 ° C. of the lubricating oil composition is preferably 5.0 mm ² / s or more, more preferably 7.5 mm ² / s or more, and still more preferably 10.0 mm ² / s or more. When the kinematic viscosity at 40 ° C. is 5.0 mm ² / s or more, it tends to be more excellent in oil film retention and evaporability at the lubrication site. Kinematic viscosity at 40 ° C. of the lubricating oil composition is preferably 30.0 mm ² / s or less, more preferably 25.0 mm ² / s, more preferably not more than 20.0 mm ² / s. When the kinematic viscosity at 40 ° C. is 30.0 mm ² / s or less, the necessary low-temperature fluidity and sufficient fuel economy tend to be obtained.

The kinematic viscosity at 100 ° C. of the lubricating oil composition is preferably 2.0 mm ² / s or more, more preferably 2.5 mm ² / s or more, and still more preferably 3.0 mm ² / s or more. When the kinematic viscosity at 100 ° C. is 2.0 mm ² / s or more, it tends to be more excellent in oil film retention and evaporability at the lubrication site. Kinematic viscosity at 100 ° C. of the lubricating oil composition is preferably 5.0 mm ² / s or less, more preferably 4.9 mm ² / s, more preferably not more than 4.8 mm ² / s. When the kinematic viscosity at 100 ° C. is 5.0 mm ² / s or less, the required low-temperature fluidity and sufficient fuel economy tend to be obtained.

  Since the lubricating oil composition according to the present embodiment is excellent in all of wear resistance, seizure resistance, and fuel efficiency, it is suitable for a manual transmission for an automobile, an automatic transmission, a continuously variable transmission, and the like. Used. The lubricating oil composition is particularly preferably used as a lubricating oil composition for automatic transmissions or continuously variable transmissions.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to a following example.

Lubricating oil compositions having the compositions shown in Tables 1 to 5 were prepared using the base oils and additives shown below.
[Base oil]
Base oil A-1: hydrorefined mineral oil (GpII, 40 ° C. kinematic viscosity: 7.71 mm ² / s, 100 ° C. kinematic viscosity: 2.254 mm ² / s, viscosity index: 99, pour point: −42 ° C., flammable Point: 162 ° C., sulfur content: 10 mass ppm or less)
Base oil A-2: hydrorefined mineral oil (GpII, 40 ° C. kinematic viscosity: 8.854 mm ² / s, 100 ° C. kinematic viscosity: 2.464 mm ² / s, viscosity index: 100, pour point: −42.5 ° C. Flash point: 168 ° C, sulfur content: 10 mass ppm or less)
Base oil A-3: Wax isomerized base oil (GpIII, kinematic viscosity at 40 ° C .: 9.072 mm ² / s, kinematic viscosity at 100 ° C .: 2.621 mm ² / s, viscosity index: 127, pour point: −37.5 ℃, flash point: 190 ℃, sulfur content: 10 mass ppm or less)
Base oil A-4: poly α-olefin (GpIV, 40 ° C. kinematic viscosity: 5 mm ² / s, 100 ° C. kinematic viscosity: 1.7 mm ² / s, viscosity index: 91, pour point—66 ° C., flash point: 157 ℃)
Base oil B: poly α-olefin (GpIV, 40 ° C. kinematic viscosity: 3100 mm ² / s, 100 ° C. kinematic viscosity: 300 mm ² / s, viscosity index: 241, pour point: −27 ° C., flash point:> 265 ° C.)
Base oil C-1: hydrorefined mineral oil (GpIII, kinematic viscosity at 40 ° C .: 19.57 mm ² / s, kinematic viscosity at 100 ° C .: 4.23 mm ² / s, viscosity index: 122, sulfur content: <10 ppm)
Base oil C-2: Hydrorefined mineral oil (GpIII, 40 ° C. kinematic viscosity: 33.97 mm ² / s, 100 ° C. kinematic viscosity: 6.208 mm ² / s, viscosity index: 133, sulfur content: 10 mass ppm or less)
Base oil C-3: poly α-olefin (GpIV, 40 ° C. kinematic viscosity: 31 mm ² / s, 100 ° C. kinematic viscosity: 5.8 mm ² / s, viscosity index: 138, pour point: −57 ° C., flash point: 246 ° C)
[Additive]
Viscosity modifier A: copolymer of ester monomer having polymerizable unsaturated bond and α-olefin, weight average molecular weight: 12800)
Viscosity modifier B: polymethacrylate (weight average molecular weight: 20000)
Performance additive C-1: Di (n-butyl) phosphite (phosphorus element conversion: 15.5% by mass)
Performance additive C-2: 1,3,4-thiadiazole (elemental sulfur conversion: 36% by mass)
Performance additive C-3: Boron-containing succinimide (in terms of boron element: 2.0% by mass)
Performance additive C-4: Additive package containing detergent, extreme pressure agent, antioxidant, corrosion inhibitor, friction modifier, rubber swelling agent, pour point depressant, antifoaming agent, etc. (phosphorus element content : 0.67 mass%, sulfur element content: 2.0 mass%, boron element content: 0.0 mass%, the content of each element is based on the total amount of additive package)
Performance additive D: Succinimide

  Each lubricating oil composition was subjected to the following evaluation tests. The results are shown in Tables 1-5.

[Abrasion resistance test]
The shell four-ball test (ASTM D4172) was performed according to the following conditions, and the wear resistance was evaluated by measuring the wear scar diameter (mm). In this test, the smaller the wear scar diameter (for example, 0.5 mm or less in the case of 392N, 1.1 mm or less in the case of 800N), the better the wear resistance.
Load: 392N or 800N
Rotation speed: 1200rpm
Temperature: 80 ° C
Test time: 30 minutes

[Seizure resistance test]
Using a Falex testing machine described in ASTM D3233, seizure load was measured according to the following conditions, and seizure resistance was evaluated. This seizure resistance indicates the extreme pressure between steels. In this test, the larger the seizure load (for example, 4000 N or more), the better the seizure resistance.
Temperature: 110 ° C
Rotation speed: 290rpm

[Fuel saving test]
Based on JPI-5S-26-99, the BF viscosity at −40 ° C. of the lubricating oil composition was measured. In this test, the smaller the BF viscosity (for example, 10000 mPa · s or less), the better the fuel economy.

Claims (4)

Lubricating base oil,
A copolymer of an ester monomer having a polymerizable unsaturated bond and an α-olefin;
Performance additives containing phosphorus, sulfur and boron as constituent elements;
Containing
The lubricating base oil has a first lubricating base oil component having a kinematic viscosity at 100 ° C. of 1.0 mm ² / s to 3.0 mm ² / s, and a kinematic viscosity at 100 ° C. of 200 mm ² / s or more. A second lubricating base oil component comprising a poly α-olefin that is
The content of the performance additive is represented by the following formulas (1), (2) and (3):
C _P ≦ 0.10 (1)
C _S ≧ 0.07 (2)
0.5 ≦ C _P / C _B ≦ 6.0 (3)
[Wherein, C _P , C _S and C _B represent element conversion values (mass%) of phosphorus, sulfur and boron in the content of the performance additive based on the total amount of the lubricating oil composition, respectively. ]
Meets the conditions
A lubricating oil composition having a kinematic viscosity at 100 ° C. of 2.0 mm ² / s to 5.0 mm ² / s.   2. The lubricating oil composition according to claim 1, wherein the content of the second lubricating base oil component is 0.5% by mass or more and 50% by mass or less based on the total amount of the lubricating oil composition.   The lubricating oil composition according to claim 1 or 2, wherein the content of the copolymer is 1.0% by mass or more and 10.0% by mass or less based on the total amount of the lubricating oil composition.   The lubricating oil composition according to any one of claims 1 to 3, which is used for an automatic transmission or a continuously variable transmission.