WO2015152143A1

WO2015152143A1 - Lubricating-oil composition

Info

Publication number: WO2015152143A1
Application number: PCT/JP2015/059892
Authority: WO
Inventors: 暢明渡部
Original assignee: 出光興産株式会社
Priority date: 2014-03-31
Filing date: 2015-03-30
Publication date: 2015-10-08
Also published as: US20170175029A1; JP6729866B2; JPWO2015152143A1

Abstract

By using a lubricating-oil composition that has a kinetic viscosity at 100°C of more than 9.3 mm²/s but no more than 12.5 mm²/s, has a high-temperature high-shear viscosity at 150°C of at least 2.9 mPa∙s, and contains (1) a base oil containing a base oil (A) that has a kinetic viscosity at 100°C between 2 and 7 mm²/s, inclusive, and a viscosity index of at most 120, (2) at least one species selected from among acrylate polymers and olefin polymers having mass-average molecular weights of at most 40,000, and (3) a lubricating-oil additive containing a sulfur-based extreme-pressure agent, a lubricating-oil composition that exhibits both reduced viscosity, improving fuel economy, and fatigue resistance, improving fatigue life, and also excels in terms of low-temperature viscosity characteristics can be provided.

Description

Lubricating oil composition

The present invention relates to a lubricating oil composition having excellent fuel economy and fatigue resistance and excellent low-temperature viscosity characteristics, and more specifically, an internal combustion engine that can lubricate gears and bearings as motorcycle engine oil, transmission oil, and the like. The present invention relates to a lubricating oil composition.

In response to demands for energy saving and carbon dioxide reduction, fuel economy is also required in lubricating oil for internal combustion engines (engine oil). For engine oils used in four-wheeled vehicles, conventionally, as means for improving fuel economy, it has been performed to reduce viscosity and improve viscosity index, and various polymers such as viscosity index improvers used therefor Proposals have also been made (for example, see Patent Documents 1 to 8). However, when engine oil having a low viscosity is used for a motorcycle, for example, from the viewpoint of fuel efficiency, various problems may occur due to a difference in mechanical structure between the four-wheel vehicle and the two-wheel vehicle (for example, Patent Document 9). reference).

Japanese Patent Laid-Open No. 10-11485 Japanese Patent No. 3955573 Japanese Patent No. 4359807 Japanese Patent No. 4283120 JP 2008-208221 A JP 2009-221382 A JP 2010-280821 A Japanese Patent No. 5319996 JP 2011-195734 A

That is, a motorcycle usually has a structure in which a transmission for transmission is lubricated with the same engine oil as well as the lubrication of the engine. Therefore, for example, when engine oil (for example, 10W-30 viscosity grade) with reduced viscosity is used in a motorcycle, fatigue damage such as pitching occurs in gears and bearings (particularly radial needle bearings in a crankshaft) of a transmission for transmission. The potential increases.

Thus, for example, in a two-wheel engine oil, since gears and bearings of a transmission for transmission are also lubricated, in addition to lowering the viscosity of the engine oil, an improvement in fatigue life, that is, improvement in fatigue resistance becomes a problem. Therefore, it is necessary to solve these problems when trying to improve fuel economy by reducing the viscosity of engine oil used in motorcycles.
An object of the present invention is to provide a lubricating oil composition that achieves both low viscosity for fuel saving and fatigue resistance for improving fatigue life, and is excellent in low-temperature viscosity characteristics.

As a result of intensive investigations in view of the above problems, the inventors of the present invention have developed a specific low molecular weight polymer in a low viscosity lubricating oil in which a kinematic viscosity at 100 ° C. and a high temperature high shear viscosity (HTHS viscosity) at 150 ° C. are defined in a specific range. It has been found that the above-described problems of the present invention can be solved by containing the present invention, and the present invention has been completed.
That is, the present invention is as follows.
[1] (1) Base oil containing base oil A having a kinematic viscosity at 100 ° C. of 2 mm ² / s to 7 mm ² / s and a viscosity index of 120 or less, (2) Mass average molecular weight of 40,000 or less one or more selected from acrylate-based polymers and olefinic polymers, and (3) containing an additive containing a sulfur-based extreme pressure agent, a kinematic viscosity at 100 ° C. is 9.3 mm ² / s ultra 12.5 mm ² / A lubricating oil composition having a high temperature and high shear viscosity at 150 ° C. of 2.9 mPa · s or more.
[2] The lubricating oil composition according to [1], wherein the CCS viscosity at −25 ° C. is 7000 mPa · s or less and the viscosity index is 135 or more.

[3] The acrylate polymer and / or olefin polymer having a mass average molecular weight of 40,000 or less is obtained from at least one selected from α-olefins having 8 to 12 carbon atoms, and the kinematic viscosity at 100 ° C. is 100 mm ^2. The lubricating oil composition according to the above [1] or [2], which is a poly α-olefin of / s to 2,000 mm ² / s.
[4] The lubrication according to any one of [1] to [3], wherein the central oil film thickness in the oil film thickness measurement in the elastohydrodynamic lubrication state (EHL) is 50 nm or more at a rolling speed of 1.6 m / s. Oil composition.
[5] The lubricating oil composition according to any one of [1] to [4], wherein a 50% failure probability (L50) is 3.0 × 10 ⁶ times or more in the fatigue life evaluation of the radial rolling bearing.
[6] The lubricating oil composition according to any one of [1] to [5], wherein the base oil further comprises a base oil having a viscosity index of more than 120.

[7] The lubricating oil composition according to any one of [1] to [6], wherein the kinematic viscosity after a shear test at 100 ° C. is 9 mm ² / s or more.
[8] The lubricating oil composition according to any one of [1] to [7], which is for an internal combustion engine.
[9] The lubricating oil composition according to any one of [1] to [8], which is for a two-wheel internal combustion engine.

[10] (1) To a base oil containing base oil A having a kinematic viscosity at 100 ° C. of 2 mm ² / s to 7 mm ² / s and a viscosity index of 120 or less, (2) mass average molecular weight 40,000 One or more kinds selected from the following acrylate-based polymers and olefin-based polymers, and (3) a lubricating oil additive containing a sulfur-based extreme pressure agent are blended, and the kinematic viscosity at 100 ° C. exceeds 9.3 mm ² / s 12 The manufacturing method of the lubricating oil composition which manufactures the lubricating oil composition which is 0.5 mm < ² > / s or less and whose high temperature high shear viscosity in 150 degreeC is 2.9 mPa * s or more.
[11] (1) Base oil containing base oil A having a kinematic viscosity at 100 ° C. of 2 mm ² / s to 7 mm ² / s and a viscosity index of 120 or less, (2) Mass average molecular weight of 40,000 or less 1 or more selected from acrylate-based polymers and olefin-based polymers, and (3) a lubricating oil additive containing a sulfur-based extreme pressure agent, and a kinematic viscosity at 100 ° C. of more than 9.3 mm ² / s and 12.5 mm ^An internal combustion engine in which a lubricating oil composition having a high temperature / high shear viscosity at 150 ° C. of 2.9 mPa · s or more is used.
[12] (1) Base oil containing base oil A having a kinematic viscosity at 100 ° C. of 2 mm ² / s to 7 mm ² / s and a viscosity index of 120 or less, (2) Mass average molecular weight of 40,000 or less 1 or more selected from acrylate-based polymers and olefin-based polymers, and (3) a lubricating oil additive containing a sulfur-based extreme pressure agent, and a kinematic viscosity at 100 ° C. of more than 9.3 mm ² / s and 12.5 mm ^A method of lubricating an internal combustion engine that is lubricated with a lubricating oil composition having a high temperature / high shear viscosity at 150 ° C. of 2.9 mPa · s or higher.

According to the present invention, it is possible to provide a lubricating oil composition having both low viscosity for fuel saving and fatigue resistance for improving fatigue life and excellent low temperature viscosity characteristics.
In addition, according to the present invention, as a lubricating oil composition for a two-wheel internal combustion engine, a lubricating oil composition that can lubricate both the engine and the transmission for transmission can be provided.

Hereinafter, the present invention will be described in more detail.
The lubricating oil composition of the present invention comprises (1) a base oil containing base oil A having a kinematic viscosity at 100 ° C. of 2 mm ² / s to 7 mm ² / s and a viscosity index of 120 or less, (2) mass average 1 or more types chosen from the acrylate type polymer and olefin type polymer of molecular weight 40,000 or less, and (3) Additives containing a sulfur type extreme pressure agent, Kinematic viscosity in 100 degreeC is more than 9.3 mm < ² > / s 12.5 mm ² / s or less, and high-temperature high shear viscosity (hereinafter referred to as “HTHS viscosity”) at 150 ° C. is 2.9 mPa · s or more.

[(1) Base oil]
The base oil used in the lubricating oil composition of the present invention contains base oil A having a kinematic viscosity at 100 ° C. of 2 mm ² / s to 7 mm ² / s and a viscosity index of 120 or less. As a base oil that can be used for a low-viscosity lubricating oil, a high-quality one having a high viscosity index has been used, but in the present invention, a base oil having a relatively low quality having a low viscosity index is also used. Can be used. That is, as the base oil A, those having a kinematic viscosity at 100 ° C. of 3 mm ² / s to 6 mm ² / s and a viscosity index of 110 or less can be preferably used from the viewpoint of lowering the viscosity and reducing the cost. Specifically, mineral base oils belonging to Group I and Group II in the API (American Petroleum Institute) base oil category can also be used.
The viscosity index of the base oil and the kinematic viscosity at 100 ° C. can be measured according to JIS K 2283 (ASTM D445).

From the above viewpoint, the base oil in the lubricating oil composition of the present invention preferably contains the base oil A in an amount of 70% by mass or more, more preferably 80% by mass or more, and still more preferably 100% by mass.
In the base oil in the present invention, it is optional to use another base oil together with the base oil A. The base oil that can be used is not particularly limited, but a base oil having a viscosity index of more than 120 can be used from the viewpoint of low-temperature viscosity characteristics as long as the effects of the present invention are not impaired. Specifically, mineral oil or synthetic base oil belonging to Group III in the API base oil category can be used, and such base oil is preferably contained in the base oil of the present invention in an amount of less than 30% by mass.
In addition, about the base oil containing the base oil A which is the base oil in the lubricating oil composition of this invention, the property is not specifically limited as long as the property prescribed | regulated about the obtained lubricating oil composition is satisfied.

In the present invention, the mineral base oil that can be used includes, for example, a crude oil fraction obtained by atmospheric distillation or a lubricating oil fraction obtained by subjecting an atmospheric residue obtained by atmospheric distillation to vacuum distillation, Recycled, refined by one or more treatments such as solvent extraction, hydrocracking, solvent dewaxing, hydrorefining, etc., or wax produced by mineral oil or Fischer-Tropsch process (gas-tri-liquid wax) Any of the base oils produced by isomerizing can be mentioned.
On the other hand, as synthetic oils, for example, poly-α-olefin, polybutene, polyol ester, dibasic acid ester, aromatic ester, phosphoric acid ester, polyphenyl ether, alkylbenzene, alkylnaphthalene, polyoxyalkylene glycol, neopentyl glycol , Silicone oil, trimethylolpropane, pentaerythritol, hindered ester, and the like can be used.

[(2) Acrylate polymer and olefin polymer]
The lubricating oil composition of the present invention is one or more selected from an acrylate polymer and an olefin polymer having a mass average molecular weight of 40,000 or less from the viewpoint of improving the fatigue resistance, particularly in the radial needle fatigue life, and extending the life. Containing.
Examples of the acrylate polymer having a mass average molecular weight of 40,000 or less include polymethacrylate (PMA), and the polymethacrylate can be used in either a dispersion type or a non-dispersion type. Specifically, so-called non-dispersed polymethacrylates such as various methacrylic acid esters or copolymers according to any combination thereof and hydrides thereof, and various methacrylic acid esters further containing nitrogen compounds are copolymerized. Examples thereof include dispersed polymethacrylate. These polymethacrylates may be used alone or in combination of two or more.

Examples of the olefin polymer having a mass average molecular weight of 40,000 or less include α-olefin homopolymers or copolymers, ethylene-α-olefin copolymers, polybutene, and the like. Of these, α-olefin homopolymers and copolymers preferably have 2 to 30 carbon atoms, more preferably 4 to 22 carbon atoms, still more preferably 6 to 16 carbon atoms, and even more preferably 6 to 6 carbon atoms. 14, particularly preferably 8-12 homopolymers and copolymers of α-olefins, which may be random or block.

Usable α-olefins include ethylene, propylene, isobutylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 1-undecene and 1-dodecene. And α-olefins having 2 to 30 carbon atoms such as 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene and 1-eicosene.
Examples of the ethylene-α-olefin copolymer include a copolymer of ethylene and α-olefin. As the α-olefin, propylene or the above α-olefin homopolymer and copolymer were used. The same thing is used. The ethylene-α-olefin copolymer may be random.
These olefinic polymers may be used alone or in combination of two or more.

These olefin polymers can be produced by any method. For example, it can be produced by a non-catalytic thermal reaction, or an organic peroxide catalyst such as benzoyl peroxide; aluminum chloride, aluminum chloride-polyhydric alcohol, aluminum chloride-titanium tetrachloride, aluminum chloride-alkyltin Friedel-Crafts type catalysts such as halides and boron fluoride; Ziegler type catalysts such as organic aluminum chloride-titanium tetrachloride and organic aluminum-titanium tetrachloride; metallocenes such as aluminoxane-zirconocene and ionic compounds-zirconocene The catalyst can be produced by homopolymerizing or copolymerizing an olefin using a known catalyst system such as a Lewis acid complex type catalyst such as an aluminum chloride-base system or a boron fluoride-base system. In the present invention, the above-mentioned olefin polymer can be used. However, in view of its thermal / oxidative stability, a hydride of an olefin polymer obtained by hydrogenating a double bond in an olefin polymer may be used. it can.

Of the above (2) acrylate-based polymers and olefin-based polymers, in the present invention, from the viewpoint of fatigue resistance, olefin-based polymers are preferably used, and have low viscosity and improved fatigue resistance, and low viscosity characteristics. From the viewpoint of improvement, a poly α-olefin preferably obtained from at least one selected from α-olefins having 8 to 12 carbon atoms and having a kinematic viscosity at 100 ° C. of 100 mm ² / s to 2,000 mm ² / s (Hereinafter referred to as “high viscosity PAO”).

The number of carbon atoms of the α-olefin, which is a raw material monomer for high-viscosity PAO, is preferably 8 or more and 12 or less, more preferably 9 or more and 11 or less, from the viewpoints of improved fatigue resistance, workability, lubricating oil adaptability, and the like. And more preferably 10. Specifically, among the α-olefins, those having 8 to 12 carbon atoms are used. The kinematic viscosity at 100 ° C. of the high-viscosity PAO is preferably 100 mm ² / s or more and 1,800 mm ² / s or less from the viewpoint of excellent viscosity index improving ability, good fluidity and excellent fatigue resistance. , more preferably 100 mm ² / s or more 1,500mm ² / s, more preferably not more than 200 mm ² / s or more 1,000mm ² / s.
The kinematic viscosity at 100 ° C. of the high viscosity PAO can be measured according to JIS K 2283 (ASTM D445).

In the present invention, the high-viscosity PAO has at least one of the following composition (I) and property (II) from the viewpoint of low viscosity, fatigue resistance, and low-temperature viscosity characteristics, and / or the following production: What was obtained by method (III) can be used more preferably.
(I) In the high-viscosity PAO, the proportion of the dimer and trimer components is preferably less than 2% by mass, more preferably less than 1.5% by mass, and less than 1.0% by mass. More preferably. Thereby, the molecular weight distribution of high-viscosity PAO is small, it becomes a more uniform composition, and a polymer in the target viscosity region can be obtained. Moreover, since there is almost no performance-decreasing component, it becomes useful as a lubricating oil component. The proportion of the dimer and trimer components can be controlled by the polymerization conditions and can be determined using gas chromatography.

(II) The high-viscosity PAO preferably has at least one of the following four properties from the viewpoints of low viscosity, fatigue resistance, and low-temperature viscosity characteristics.
(II-1) amorphous, (II-2) viscosity index is 150 or more, (II-3) pour point is -15 ° C or less, (II-4) average carbon number is 4 or more 15 or less.
The higher the viscosity index, the lower the temperature dependency and the better the low temperature characteristics. Therefore, the viscosity index of the high viscosity PAO is more preferably 170 or more. Further, the lower the low temperature pour point, the better the low temperature characteristics. Therefore, the pour point of high viscosity PAO is more preferably −20 ° C. or less, and further preferably −30 ° C. or less. Furthermore, the average carbon number of the high viscosity PAO is more preferably 8 or more and 12 or less.
Here, the term “amorphous” generally means that the melting point is not present, only the glass transition temperature is present, transparency is present, the volume change upon cooling and solidification is small, and the like. It means having the characteristics that appear in the case. The viscosity index of high-viscosity PAO can be measured according to JIS K 2283 (ASTM D445), the pour point can be measured according to JIS K 2269, and the average carbon number can be measured by NMR measurement.

(III) The high-viscosity PAO described above is preferably produced, for example, according to the method described in International Publication WO2012 / 035710 Pamphlet.
Specifically, the high-viscosity PAO is a compound that can react with the meso-type transition metal compound (A) and (B-1) the transition metal compound (A) or a derivative thereof to form an ionic complex. And (B-2) a polymerization catalyst containing at least one compound (B) of aluminoxane and an organoaluminum compound (C), one type of the α-olefin, or two or more types Can be obtained by polymerizing.

The meso-type transition metal compound (A) is described in paragraphs [0036] to [0063] of International Publication WO2012 / 035710, the compound (B) is described in paragraphs [0065] to [0075] of the same pamphlet, and The organoaluminum compound (C) is described in paragraphs [0077] and [0078] of the pamphlet, and the obtained polymerization catalyst is described in paragraphs [0076] and [0079] to [0089] of the pamphlet. Each can be used.

Specifically, the polymerization catalyst is preferably (1,1′-ethylene) (2,2′-tetramethyldisilene) -bis (indenyl) zirconium dichloride, (1,1′-tetramethylene dichloride). Silylene) (2,2′-ethylene) -bis (indenyl) zirconium dichloride, (1,1′-tetramethylethylene) (2,2′-tetramethyldisilylene) -bis (indenyl) zirconium dichloride, (1, 1′-tetramethylenedisilylene) (2,2′-tetramethylethylene) -bis (indenyl) zirconium dichloride, (1,1′-dimethylethylenesilylenemethylene) (2,2′-ethylene) -bis (3- Methylindenyl) zirconium dichloride, (1,1′-ethylene) (2,2′-dimethylethylenesilylmethylene) -bis (3 Methylindenyl) zirconium dichloride, (1,1′-ethylene) (2,2′-tetramethyldiggermylene) -bis (indenyl) zirconium dichloride, (1,1′-tetramethyldiggermylene) (2, 2'-ethylene) -bis (indenyl) zirconium dichloride,

(1,1′-ethylene) (2,2′-tetramethyldisiylene) -bis (3-methylindenyl) zirconium dichloride, (1,1′-tetramethyldisylylene) (2,2′-ethylene) -Bis (3-methylindenyl) zirconium dichloride, (1,1'-tetramethylethylene) (2,2'-tetramethyldisylylene) -bis (3-methylindenyl) zirconium dichloride, (1,1 ' -Tetramethyldisilylene) (2,2'-tetramethylethylene) -bis (3-methylindenyl) zirconium dichloride, (1,1'-dimethylylylenemethylene) (2,2'-ethylene) -bis ( 3-methylindenyl) zirconium dichloride, (1,1'-ethylene) (2,2'-dimethylethylenesilylmethylene) -bis (3-methylindenyl) zirconi Mudichloride, (1,1′-ethylene) (2,2′-tetramethyldiggermylene) -bis (3-methylindenyl) zirconium dichloride, (1,1′-tetramethyldiggermylene) (2,2 Examples include '-ethylene) -bis (3-methylindenyl) zirconium dichloride and the like, and those obtained by replacing zirconium in these compounds with titanium or hafnium. Further, it may be a compound similar to another group or a lanthanoid series metal element.
The polymerization method is not particularly limited, but can be performed according to the method described in paragraphs [0090] to [0095] of the pamphlet.

From the viewpoint of fatigue resistance for improving fatigue life, the molecular weight of the above (2) acrylate polymer and olefin polymer is 40,000 or less in terms of mass average molecular weight. 000 or less, more preferably 30,000 or less, further preferably 25,000 or less, and particularly preferably 20,000 or less. The lower limit is not particularly limited, but is preferably 5,000 or more from the viewpoint of fatigue resistance and low-temperature viscosity characteristics. The mass average molecular weight can be determined by a gel permeation chromatography (GPC) method and can be determined from a calibration curve prepared using polystyrene. For example, the weight average molecular weight of each polymer can be calculated as a polystyrene equivalent value by the following GPC method.
<GPC measurement device>
Column: TOSO GMHHR-H (S) HT
・ Detector: RI detector WATERS 150C for liquid chromatogram
<Measurement conditions>
Solvent: 1,2,4-trichlorobenzene Measurement temperature: 145 ° C
-Flow rate: 1.0 ml / min-Sample concentration: 2.2 mg / ml-Injection volume: 160 microliters-Calibration curve: Universal Calibration
・ Analysis program: HT-GPC (Ver, 1.0)

The kinematic viscosity at 100 ° C. of the (2) acrylate polymer and olefin polymer is preferably 5 mm ² / s or more and 15,000 mm ² / s or less from the viewpoint of low viscosity, fatigue resistance and low temperature viscosity characteristics. , more preferably 50 mm ² / s or more 10,000 mm ² / s or less, more preferably 100 mm ² / s or more 10,000 mm ² / s or less, particularly preferably not more than 100 mm ² / s or more 5,000 mm ² / s .
Further, the viscosity index of the (2) acrylate polymer and olefin polymer is preferably 120 or more, and more preferably 150 or more. On the other hand, the viscosity index is preferably 350 or less, and more preferably 250 or less.

The (2) acrylate polymer and / or olefin polymer is preferably contained in the lubricating oil composition of the present invention in a range of 0.1% by mass or more and less than 20% by mass based on the total amount of the composition. . If this amount is within the above range, in the resulting lubricating oil composition, an improvement in fatigue resistance as well as a reduction in viscosity can be achieved, and good low temperature viscosity characteristics can be obtained. From the above viewpoint, the content of the acrylate polymer and / or the olefin polymer is more preferably 0.5% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass based on the total amount of the composition. It is as follows.

[(3) Lubricating oil additive containing sulfur-based extreme pressure agent]
The lubricating oil composition of this invention contains the lubricating oil additive containing a sulfur type extreme pressure agent with the said polymer.
Examples of the sulfur-based extreme pressure agent include zinc dithiophosphate (ZnDTP), sulfurized olefin, dialkyl polysulfide, diaryl polysulfide, zinc dithiocarbamate, disulfides, sulfurized fats and oils, sulfurized esters, thiocarbonates, and thiocarbamates. Furthermore, thiophosphite esters, thiophosphate esters, thiophosphonate esters and the like, amine salts thereof, metal salts thereof, and the like can be given. The said sulfur type extreme pressure agent may be used by 1 type, and may be used in combination of 2 or more type. The content is preferably 0.01% by mass or more and 10% by mass or less, more preferably 0.5% by mass or more and 5% by mass or less, based on the total amount of the composition. By using the above-mentioned sulfur-based extreme pressure agent, for example, in a two-wheel engine using a wet clutch, a film having a small friction coefficient can be formed by reacting with a metal surface to reduce friction and improve lubricity. preferable.

In the lubricating oil composition of the present invention, as other additives, any of the additives usually used as a lubricating oil additive can be used, preferably those used as a lubricating oil additive for motorcycles. Used. Specifically, non-sulfur extreme pressure agents, friction modifiers, ashless dispersants, metal detergents, antioxidants, metal deactivators, rust inhibitors, antifoaming agents, anti-emulsifiers and coloring Lubricating oil additives typified by agents and the like can be used.
Non-sulfur extreme pressure agents include phosphorous-containing extreme pressure agents such as phosphites, phosphate esters, phosphonate esters, alkylhydrogen phosphites and their amine salts, or metal salts thereof. Can be mentioned.

Further, in the lubricating oil composition of the present invention, a metal friction modifier and an ashless friction modifier can be contained in order to improve fuel saving characteristics. Specifically, examples of the friction modifier include organic molybdenum compounds, fatty acids, higher alcohols, fats, amides, sulfurized esters, phosphate esters, phosphite esters, phosphate ester amine salts, and the like. These friction modifiers can be used alone or in any combination of two or more, but the content is usually in the range of 0.01% by mass or more and 10% by mass or less based on the total amount of the composition.

Examples of the ashless dispersant include polybutenyl succinimide having a polybutenyl group having a mass average molecular weight of 900 to 3,500, polybutenylbenzylamine, polybutenylamine, and boric acid modified products thereof. Derivatives and the like. These ashless dispersants can be contained singly or in any desired combination, but the content is usually in the range of 0.01% by mass to 10% by mass based on the total amount of the composition.

Examples of metal detergents include sulfonates, phenates, salicylates, and naphthenates of alkali metals (sodium (Na), potassium (K), etc.) or alkaline earth metals (calcium (Ca), magnesium (Mg), etc.). Can be mentioned. These can be used alone or in combination. What is necessary is just to select suitably the total base number and content of these metal type detergents according to the performance of the required lubricating oil. The total base number is usually 0 mgKOH / g or more and 500 mgKOH / g or less, preferably 10 mgKOH / g or more and 400 mgKOH / g or less by the perchloric acid method. Further, the content is usually in the range of 0.1% by mass or more and 10% by mass or less based on the total amount of the composition.

As an antioxidant, any one of known antioxidants conventionally used as an antioxidant for engine oils can be appropriately selected and used. A phenolic antioxidant or an amine antioxidant can be used. Any of an agent, a molybdenum-based antioxidant, a sulfur-based antioxidant, a phosphorus-based antioxidant, and the like can be used. Specifically, amine-based antioxidants such as alkylated diphenylamine, phenyl-α-naphthylamine, alkylated phenyl-α-naphthylamine; 2,6-di-tert-butylphenol, 4,4′-methylenebis (2,6 -Di-tert-butylphenol), isooctyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) Examples thereof include phenolic antioxidants such as propionate; sulfur antioxidants such as dilauryl-3,3′-thiodipropionate; phosphorus antioxidants such as phosphite; and molybdenum antioxidants. These antioxidants can be used alone or in any combination of two or more. The blending amount is in the range of 0.01% by mass or more and 10% by mass or less based on the total amount of the lubricating oil composition.

Examples of the metal deactivator include benzotriazole, triazole derivatives, benzotriazole derivatives, thiadiazole derivatives, etc., and the content thereof is usually in the range of 0.01% by mass to 3% by mass based on the total amount of the composition. is there.
Examples of the rust preventive include: fatty acid; alkenyl succinic acid half ester; fatty acid soap; alkyl sulfonate; alkaline earth metal (calcium (Ca), magnesium (Mg), barium (Ba), etc.) sulfonate, phenate, Examples include salicylates and naphthenates; polyhydric alcohol fatty acid esters; fatty acid amines; oxidized paraffins; alkyl polyoxyethylene ethers, and the content thereof is usually in the range of 0.01% by mass to 5% by mass based on the total amount of the composition. It is.

As the antifoaming agent, liquid silicone is suitable, and for example, methyl silicone, fluorosilicone, polyacrylate, and the like can be used. The preferable content of these antifoaming agents is 0.0005% by mass or more and 0.1% by mass or less based on the total amount of the composition.
As an anti-emulsifier, ethylene propylene block polymer, alkaline earth metal (calcium (Ca), magnesium (Mg), etc.) sulfonate, phenate, salicylate, naphthenate, etc. can be used, and the content is usually based on the total amount of the composition It is 0.0005 mass% or more and 1 mass% or less.
As the colorant, a dye, a pigment, or the like can be used, and the content thereof is usually 0.001% by mass or more and 1% by mass or less based on the total amount of the composition.

As mentioned above, sulfur-based extreme pressure agents, and if necessary, extreme pressure agents other than sulfur-based materials, friction modifiers, antioxidants, metal-based detergents, ashless dispersants, metal inertness Lubricating oil composition formed by blending various additives selected from an agent, a rust inhibitor, an antifoaming agent, a colorant, and the like, usually contains the blended product, In some cases, at least a part of the blended additive may react to form another compound.

[Lubricating oil composition]
The lubricating oil composition of the present invention comprises (1) a base oil containing a base oil A having a kinematic viscosity at 100 ° C. of 2 mm ² / s to 7 mm ² / s and a viscosity index of 120 or less, (2 ) Containing an acrylate polymer and / or olefin polymer having a weight average molecular weight of 40,000 or less, and (3) a lubricating oil additive containing a sulfur-based extreme pressure agent. in is the kinematic viscosity of 9.3 mm ² / s or less ultrasonic 12.5 mm ² / s, and by the 0.99 ° C. 2.9 mPa · s or more HTHS viscosity at, fatigue and low viscosity for fuel economy A lubricating oil composition having both fatigue resistance for improving the life and excellent low-temperature viscosity characteristics can be obtained.

As described above, in the lubricating oil composition of the present invention, kinematic viscosity at 100 ° C. is not more than 9.3 mm ² / s Ultra 12.5 mm ² / s, and HTHS viscosity of 2.9 mPa · s or more. The HTHS viscosity is a reduced viscosity under high temperature and high shear conditions. By setting the kinematic viscosity at 100 ° C. and the HTHS viscosity at 150 ° C. within the above ranges, a 10W-30 viscosity grade low viscosity motorcycle engine oil can be obtained. It can be used, and can maintain lubricity and achieve low viscosity, contributing to fuel saving. From this point of view, the kinematic viscosity at 100 ° C. of the lubricating oil composition is preferably not more than 9.3 mm ² / s Ultra 11.0 mm ² / s, HTHS viscosity at 0.99 ° C. is a 3.0 mPa · s or more It is preferable. Here, although there is no restriction | limiting in particular about the upper limit of the HTHS viscosity in 150 degreeC, Usually, it is about 3.7 mPa * s.

The HTHS viscosity at 150 ° C. in the lubricating oil composition can be adjusted by selecting the viscosity of the base oil, the type, molecular weight, content, and the like of the acrylate polymer or olefin polymer and other viscosity index improvers. Further, the kinematic viscosity at 100 ° C. of the lubricating oil composition can be measured according to JIS K 2283 (ASTM D445), and the HTHS viscosity at 150 ° C. can be measured according to JPI-5S-36-03 (ASTM D 4683). Can be measured.

The lubricating oil composition of the present invention preferably further has a low-temperature viscosity (CCS viscosity at −25 ° C.) of 7,000 mPa · s or less and a viscosity index of 135 or more. By setting either the CCS viscosity or viscosity index at −25 ° C. within the above range, it is possible to maintain lubricity and achieve low viscosity, and to obtain better low-temperature viscosity characteristics, contributing to fuel saving. Can do. From this viewpoint, the CCS viscosity at −25 ° C. of the lubricating oil composition is more preferably 6,000 mPa · s or less, further preferably 5,500 mPa · s or less, and the viscosity index is more preferably 137 or more, Preferably it is 140 or more.
The CCS viscosity at −25 ° C. can be adjusted by selecting the viscosity of the base oil, the type, molecular weight, content, etc. of the acrylate polymer or olefin polymer and other viscosity index improvers. Further, the CCS viscosity at −25 ° C. in the lubricating oil composition can be measured according to JIS K 2010 (ASTM D 2602), and the viscosity index can be measured according to JIS K 2283 (ASTM D 445). .

Furthermore, the lubricating oil composition of the present invention preferably has a kinematic viscosity after shearing at 100 ° C. of 9 mm ² / s or more. When the kinematic viscosity after the shear test at 100 ° C. is less than 9 mm ² / s, the lubricity is not sufficient due to a decrease in viscosity at high temperature. In view of the above, the kinematic viscosity at 100 ° C. after shearing of the lubricating oil composition of the present invention is preferably, 9.3 mm ² / s or more 11.0 mm ² / s or less.
In the present invention, “viscosity after a shear test at 100 ° C.” is, for example, controlling the viscosity of the base oil by the molecular weight or content of an acrylate polymer or olefin polymer or other viscosity index improver. Can be adjusted. The shearing method conforms to JPI-5S-29 (ASTM D3945).

From the viewpoint of providing a lubricating oil composition having a low viscosity for fuel saving and excellent low temperature viscosity characteristics, the lubricating oil composition of the present invention has a central oil film thickness in oil film thickness measurement of elastohydrodynamic lubrication (EHL). However, at a rolling speed of 1.6 m / s, it is preferably 50 nm or more, more preferably 55 nm or more, and further preferably 66 nm or more.
The oil film thickness is measured using an EHL ultrathin film measuring system manufactured by PCS under the conditions of load: 20 N, temperature: 120 ° C., rolling speed: 0.05 to 1.6 m / s, and oil film thickness: 1 to 250 nm. be able to.

Further, from the viewpoint of providing a lubricating oil composition excellent in fatigue resistance for improving the fatigue life, the lubricating oil composition of the present invention has a 50% failure probability as a pitching life in the fatigue life of a radial rolling bearing ( L50) is preferably 3.0 × 10 ⁶ times or more, more preferably 4.0 × 10 ⁶ times or more, still more preferably 5.0 × 10 ⁶ times or more, particularly 6.0 × 10 ⁶ times or more. It is preferable that
The fatigue life evaluation can be performed as a load: 3000 N, temperature: 120 ° C., rotation speed: 2000 rpm, bearing: radial bearing (solid needle bearing, NSK LM1710) using a radial needle bearing fatigue evaluation tester manufactured by A & D. it can.

[Internal combustion engine]
Since the lubricating oil composition of the present invention has the above-described configuration and operation effects, it can be preferably used as a lubricating oil composition for internal combustion engines, and in particular, low viscosity and improved fatigue life for fuel saving. It is suitable for lubrication of each member of the engine because it has both fatigue resistance and excellent low temperature viscosity characteristics, and for a two-wheeled vehicle having a structure in which the transmission for transmission is also lubricated with the same engine oil, that is, It can be suitably used for lubricating a two-wheel internal combustion engine.

[Method for producing lubricating oil composition]
The present invention also includes (1) a base oil containing base oil A having a kinematic viscosity at 100 ° C. of 2 mm ² / s to 7 mm ² / s and a viscosity index of 120 or less, and (2) a weight average molecular weight of 40, 000 following acrylate polymer and / or an olefin-based polymer, and (3) by blending a lubricating oil additive containing a sulfur-based extreme pressure agent, a kinematic viscosity at 100 ° C. is 9.3 mm ² / s ultra 12.5 mm ² It is related with the manufacturing method of the lubricating oil composition which manufactures the lubricating oil composition whose HTHS viscosity in 150 degreeC is 2.9 mPa * s or more.
Lubricating oil additive (3) containing the above base oil (1), an acrylate polymer and / or an olefin polymer (2) having a weight average molecular weight of 40,000 or less, and a sulfur-based extreme pressure agent, and a lubricant having specific properties obtained. The oil composition is as described above. Regarding the method of blending the polymer (2) and the lubricating oil additive (3) with the base oil (1), as long as the respective components are blended so as to have the above-mentioned specified ranges of 100 ° C. kinematic viscosity and 150 ° C. HTHS viscosity, There is no restriction, and there are no particular restrictions on the blending order, blending conditions, and the like.

EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not restrict | limited at all by these examples.
[Evaluation items and methods]
Each property of the lubricating oil composition was measured by the following method.
(1) Kinematic viscosity (40 ° C., 100 ° C.): Measured according to JIS K 2283 (ASTM D 445).
(2) Viscosity index (VI: Viscosity Index): Measured according to JIS K 2283 (ASTM D 445).
(3) CCS viscosity (Cold Cracking Simulator): The viscosity at −25 ° C. was measured according to JIS K 2010 (ASTM D 2602).

(4) HTHS viscosity (High Temperature High Shear): Measured under the following conditions in accordance with JPI-5S-36-03 (ASTM D4683).
-Equipment: TBS high temperature viscometer (Tapered Bearing Simulator)
-Shear rate: 10 ⁶ sec ^-1
・ Rotation speed (motor): 3000rpm
・ Spacing (rotor / stator): 2 to 3 μm
・ Sample volume: 20-50ml
・ Measurement time: Calibration 4-6 hours, test 15 minutes

(5) Shear test: The test was conducted according to JPI-5S-29 (ASTM D3945).
(6) Melting point: Measured with a differential scanning calorimeter (Perkin Elmer, DSC-7).
(7) Pour point: Measured according to JIS K 2269.
(8) Dimer and trimer component amounts: Measured by gas chromatography (GC).
(9) Average carbon number: Determined from peak areas of 0.9 ppm and 1.2 ppm by NMR measurement.
(10) Fatigue life evaluation: Measured under the following conditions using the following apparatus.
・ Device: Radial needle bearing fatigue evaluation tester manufactured by A & D Co. ・ Load: 3000 N, temperature: 120 ° C., rotation speed: 2000 rpm
・ Bearing: Radial bearing (Solid needle bearing, NSK LM1710)
Test conditions: 6 units are filled with test oil and started simultaneously under the above conditions. The time when each device exceeded the vibration limiter was recorded as the lifetime. Six data were subjected to Weibull plotting, and 10% failure probability L10 (times) and 50% failure probability L50 (times) were calculated from the approximate line.
(11) Oil film thickness measurement: Measured under the following conditions using the following apparatus.
・ Equipment: EHL ultra-thin film measurement system (EHD2) manufactured by PCS
Load: 20 N, temperature: 120 ° C., rolling speed: 0.2 m / s, 1.6 m / s

Examples 1 to 7 and Comparative Examples 1 and 2
As shown in Table 1, after preparing various lubricating oil compositions by blending various additives into the base oil shown in the table, for each of the resulting lubricating oil compositions, kinematic viscosity (40 ° C, 100 ° C), Various properties such as viscosity index, HTHS viscosity at 150 ° C., CCS viscosity at −25 ° C., viscosity after shear test (100 ° C.) and the like were measured. Moreover, fatigue life and oil film thickness were evaluated about these lubricating oil compositions. In addition, the compounding quantity of each polymer in Table 1 shows the compounding quantity (mass%) as a resin part.
The results are shown in Table 1.

In addition, the used base oil and each additive are as follows.
(1) Base oil 150 N: 100 ° C. kinematic viscosity; 5.28 mm ² / s, viscosity index; 104
(2) PMA-1: polymethacrylate, mass average molecular weight; about 35,000
(3) High viscosity PAO-1: mass average molecular weight; about 24,000, 100 ° C. kinematic viscosity; 710 mm ² / s, amorphous, pour point; −30 to −40 ° C., dimer and trimer components 1% by weight or less, raw material monomer; 1-decene (4) high viscosity PAO-2: mass average molecular weight; about 12,300, 100 ° C. kinematic viscosity; 230 mm ² / s, amorphous, pour point; −30 ˜−40 ° C., dimer and trimer component amounts; 1 mass% or less, raw material monomer; 1-decene (5) high viscosity PAO-3: mass average molecular weight; about 8,000, 100 ° C. kinematic viscosity; ² / s, amorphous, pour point; −30 to −40 ° C., dimer and trimer component amounts; 1% by mass or less, raw material monomer; 1-decene

(6) PAO-a: ethylene / propylene copolymer, mass average molecular weight; about 14,000, 100 ° C. kinematic viscosity; 2,000 mm ² / s, viscosity index; 300
(7) PAO-b: manufactured by Exxon Mobil Co., Ltd., SPECTRASYN 100 (poly α-olefin (polymer of α-olefin having 4 to 22 carbon atoms)), mass average molecular weight: about 16,000, moving at 100 ° C. Viscosity: 100 mm ² / s, viscosity index: 170
(8) Polybutene: mass average molecular weight; about 1,300
(9) OCP: olefin copolymer (ethylene / propylene copolymer), weight average molecular weight; about 90,000
(10) PMA-2: polymethacrylate, mass average molecular weight; about 400,000
(11) Package additive: Sulfur-based extreme pressure agent: Zinc dithiophosphate (10), Ashless-based dispersant: Polybutenyl succinimide (20), Metal-based detergent: Ca phenate (12.2), Ca Sulfonate (5.6), antioxidant: amine antioxidant (8.9), phenolic antioxidant (4.4), others: friction modifier, rust inhibitor, metal deactivator (5 .6), diluent oil: (33.3). Figures in parentheses indicate mass% relative to the total amount of package additive.

The compositions of Examples 1 to 7, which are the lubricating oil composition of the present invention, are prepared by blending a base oil with an acrylate polymer or olefin polymer having a molecular weight within the range specified by the present invention, and various lubricating oil additives. The viscosity (100 ° C.) and the HTHS viscosity (150 ° C.) were adjusted within the range specified in the present invention, and the radial fatigue life and the central oil film thickness were both excellent.
On the other hand, Comparative Examples 1 and 2 blended with an acrylate polymer and an olefin polymer having a molecular weight outside the scope of the present invention both have kinematic viscosity (100 ° C.) and HTHS viscosity (150 ° C.) within the scope of the present invention. Even if it adjusted, it was inferior to both radial fatigue life and a center oil film thickness.

The lubricating oil composition of the present invention has both low viscosity for fuel saving and fatigue resistance for improved fatigue life, and is excellent in low temperature viscosity characteristics. In particular, since both the engine and the transmission for shifting can be lubricated, it can be suitably used as a lubricating oil composition for a two-wheeled internal combustion engine.

Claims

(1) Base oil containing base oil A having a kinematic viscosity at 100 ° C. of 2 mm 2 / s to 7 mm 2 / s and a viscosity index of 120 or less, (2) An acrylate system having a mass average molecular weight of 40,000 or less one or more selected from polymers and olefinic polymers, and (3) containing a lubricating oil additive containing a sulfur-based extreme pressure agent, a kinematic viscosity at 100 ° C. is 9.3 mm 2 / s ultra 12.5 mm 2 / s A lubricating oil composition having a high temperature and high shear viscosity at 150 ° C. of 2.9 mPa · s or higher.
The lubricating oil composition according to claim 1, wherein the CCS viscosity at -25 ° C is 7000 mPa · s or less, and the viscosity index is 135 or more.
The acrylate polymer and olefin polymer having a mass average molecular weight of 40,000 or less are obtained from at least one selected from α-olefins having 8 to 12 carbon atoms, and the kinematic viscosity at 100 ° C. is 100 mm 2 / s to 2 a 000 mm 2 / s or less of poly α- olefin lubricating oil composition according to claim 1 or 2.
The lubricating oil composition according to any one of claims 1 to 3, wherein a central oil film thickness in an elastohydrodynamic lubrication state (EHL) oil film thickness measurement is 50 nm or more at a rolling speed of 1.6 m / s.
The lubricating oil composition according to any one of claims 1 to 4, wherein the fatigue life evaluation of the radial rolling bearing has a 50% failure probability (L50) of 3.0 × 10 6 times or more.
The lubricating oil composition according to any one of claims 1 to 5, wherein the base oil further comprises a base oil having a viscosity index exceeding 120.
The lubricating oil composition according to any one of claims 1 to 6, wherein the kinematic viscosity after a shear test at 100 ° C is 9 mm 2 / s or more.
The lubricating oil composition according to any one of claims 1 to 7, which is used for an internal combustion engine.
The lubricating oil composition according to any one of claims 1 to 8, which is used for a two-wheel internal combustion engine.
(1) To a base oil containing a base oil A having a kinematic viscosity at 100 ° C. of 2 mm 2 / s to 7 mm 2 / s and a viscosity index of 120 or less, (2) an acrylate having a mass average molecular weight of 40,000 or less at least one member selected from the series polymers and olefinic polymers, and (3) by blending a lubricating oil additive containing a sulfur-based extreme pressure agent, a kinematic viscosity at 100 ° C. is 9.3 mm 2 / s ultra 12.5 mm 2 / S or less, and the manufacturing method of the lubricating oil composition which manufactures the lubricating oil composition whose high temperature high shear viscosity in 150 degreeC is 2.9 mPa * s or more.
(1) To a base oil containing a base oil A having a kinematic viscosity at 100 ° C. of 2 mm 2 / s to 7 mm 2 / s and a viscosity index of 120 or less, (2) an acrylate having a mass average molecular weight of 40,000 or less at least one member selected from the series polymers and olefinic polymers, and (3) by blending a lubricating oil additive containing a sulfur-based extreme pressure agent, a kinematic viscosity at 100 ° C. is 9.3 mm 2 / s ultra 12.5 mm 2 An internal combustion engine in which a lubricating oil composition having a high temperature / high shear viscosity at 150 ° C. of 2.9 mPa · s or more is used.