WO2018033785A1

WO2018033785A1 - Lubricant composition

Info

Publication number: WO2018033785A1
Application number: PCT/IB2017/000897
Authority: WO
Inventors: 鈴木　寛之; 康小野寺; 高士本多; 豊治金子; 山守　一雄
Original assignee: エクソンモービルリサーチアンドエンジニアリングカンパニー
Priority date: 2016-08-02
Filing date: 2017-08-02
Publication date: 2018-02-22
Also published as: JP2018021107A; JP6896384B2; EP3495463A1; US20200181529A1; SG11201900784YA

Abstract

Provided is a lubricant composition capable of reducing friction while ensuring abrasion resistance, even when the viscosity is reduced. The lubricant composition contains a lubricant base oil, (A) a detergent containing magnesium, (B) a compound containing boron, and (C) a zinc dialkyl dithiophosphate, wherein the lubricant composition is characterized in that: the amount of component (A) is in the range of 200 to 1200 mass ppm in terms of the concentration of [Mg] according to the mass ppm with respect to the mass of the lubricant composition; the amount of component (C) is in the range of 300 to 1000 mass ppm terms of the concentration of [P] according to the mass ppm of phosphate by mass with respect to the mass of the lubricant composition; the component (C) comprises at least one selected from a zinc dialkyl dithiophosphate having a primary alkyl group and/or a secondary alkyl group; the lubricant composition includes at least one zinc dialkyl dithiophosphate having a secondary alkyl group; the ratio (mass ratio) of the zinc dialkyl dithiophosphate having a primary alkyl group and the zinc dialkyl dithiophosphate having a secondary alkyl group is in the range of 70:30 to 0:100; and the concentration of [B] according to the mass ppm of boron with respect to the mass of the lubricant composition is in the range of 100 to 300 mass ppm.

Description

Specification

Title of invention: Lubricating oil composition

Technical field

TECHNICAL FIELD [0001] The present invention relates to a lubricating oil composition, and more particularly to a lubricating oil composition for an internal combustion engine, in particular, a lubricating oil composition for a gasoline engine.

Background art

[0002] Lubricating oil compositions are widely used in the automotive field such as for internal combustion engines, automatic transmissions, and gear oils. In recent years, low viscosity has been demanded to improve fuel efficiency, but the oil film becomes thinner due to the low viscosity, and friction cannot be reduced sufficiently. In view of this, Molybdenum Mochi Tachibana (MoDTC), which can reduce friction by producing molybdenum disulfide under boundary lubrication conditions, has been used in the past. In this case, it is usual to use a calcium-based detergent in combination (for example, Japanese Patent Application Laid-open No. 20 013-1959 494 (Patent Document 1)). However, with this combination, there is a limit to the reduction of friction, and the fuel consumption cannot be improved sufficiently.

[0003] It is also known to use a magnesium-based detergent as the detergent (for example, Japanese Patent Laid-Open No. 2 0 1 1-1 8 4 5 6 6 (Patent Document 2) and Japanese Patent Laid-Open No. 1 3 2 8 2 6 5 (Patent Document 3)). The use of magnesium-based detergents can reduce friction more than calcium-based detergents, but there is a problem of wear and brittleness.

Prior art documents

Patent Literature

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2 0 1 3-1 9 9 5 94

Patent Document 2: Japanese Patent Laid-Open No. 2 0 1 1-1 8 4 5 6 6

Patent Document 3: Japanese Patent Laid-Open No. 2 0 0 6-3 2 8 2 6 5

Summary of the Invention

Problems to be solved by the invention [0005] An object of the present invention is to provide a lubricating oil composition that can reduce friction while ensuring wear resistance even when the viscosity is reduced, and as a preferred embodiment, a lubricating oil composition for an internal combustion engine, It is preferable to provide a lubricating oil composition for supercharged gasoline engines. ·

Means for solving the problem

[0006] As a result of intensive studies, the present inventors have added a specific amount of a magnesium-based detergent and a zinc dialkyldithiophosphate having a specific structure to a lubricating base oil in a specific amount, and are contained in the composition. The inventors have found that the above object can be achieved by specifying the boron content.

That is, the present invention provides:

A lubricating oil composition comprising a lubricating base oil, (A) a detergent having magnesium, (B) a compound having boron, and (C) a zinc dialkyldithiophosphate.

(A) The amount of the component is in the range of 200 to 1 200 mass ppm as the concentration [Mg] of the magnesium mass ppm relative to the mass of the lubricating oil composition,

(C) the amount of the component is in the range of 300-1 000 mass p pm as the concentration [P] by the mass p pm of phosphorus with respect to the mass of the lubricating oil composition;

The component (C) is one or more selected from dialkyl dithiodi zinc phosphates having a primary alkyl group and a secondary or secondary alkyl group, provided that the lubricating oil composition has a secondary alkyl group. The ratio (mass ratio) of the dialkyl dititanium zinc phosphate having a primary alkyl group to the dialkyl dititanium zinc phosphate having a secondary alkyl group is at least 70:30 to 0. : The range is 1 00,

A lubricating oil composition characterized in that the concentration [B] of boron by mass P pm relative to the mass of the lubricating oil composition is in the range of 100 to 300 mass p pm.

[0008] In a preferred embodiment of the present invention, the lubricating oil composition further has at least one of the following features (1) to (7).

(1) (B) As an ashless dispersant containing boron as a compound containing boron, 1 Including the above.

(2) It further contains a detergent (Α ') containing calcium, and {[Mg] / ([Mg] + [Ca])} X 1 00≥5 ([C a] is the mass of the lubricating oil composition. The concentration of calcium relative to P pm).

(3) It further includes a friction modifier having molybdenum, and satisfies [Mg] / [Mo] <2.5 ([Mo] indicates the concentration of molybdenum by p p m relative to the mass of the lubricating oil composition).

(4) CCS viscosity at 35 ° C is 6.2 Pa or less.

(5) 1 High temperature high shear viscosity (HTHS viscosity) at 50 ° C is 1.5 to 2.9 m Pa's.

(6) The kinematic viscosity at 100 ° C is less than 9.3 mm ² / s.

(7) For internal combustion engines.

Furthermore, the present invention relates to a method for reducing friction while maintaining low wear by using the lubricating oil composition or the lubricating oil composition according to the above embodiments (1) to (7).

The invention's effect

[0009] The lubricating oil composition of the present invention can reduce friction while ensuring wear resistance even when the viscosity is lowered. Particularly, the lubricating oil composition for an internal combustion engine and further for a supercharged gasoline engine. It can be suitably used as a lubricating oil composition.

BEST MODE FOR CARRYING OUT THE INVENTION

[0010] Lubricating base oil

The lubricating base oil in the present invention is not particularly limited. Either a mineral oil or a synthetic oil may be used, and these can be used alone or in combination.

[0011] As mineral oil, for example, a lubricating oil fraction obtained by distillation under reduced pressure of atmospheric residual oil obtained by atmospheric distillation of crude oil is subjected to solvent removal, solvent extraction, hydrocracking, solvent removal. Or refined by one or more treatments such as hydrorefining, etc., or fox isomerized mineral oil, GTL (Gasto L iquid) base oil, ATL (A sphaltto L iquid) base oil, vegetable oil system Base oil or these Can be mentioned.

[0012] Synthetic oils include, for example, polybutene or hydrides thereof; 1-year-old Kuten-year-old Rigoma 1, 1-decene oligomer, etc. Poly-α-year-old refin or its hydride; 2-ethylhexyl laurate, Monoesters such as 2-ethylhexyl palmitate and 2-ethylhexyl stearate; di-decylglutarate, di-2-ethylhexyl adipate, diisodecyl adipate, didecyl adipate, di-2- Diesters such as ethyl hexyl sebake; neopentyl glycol di-2-ethyl hexanoe, neopentylglycol-ruze η--pure kutanoeite, neopentylglycol-ruze η-decanoate, trimethylol propane tree η —Principal Kutanoe, 卜 Limetrol roll pantry η—Dekanoe Ichigo, Pentaeris Polytetraester η-pentanoe monopoly, pentaerythritol Polytetraester such as monotetra-η-hexanoate, pentaerythritol tetra-2-ethylhexanoate; aromatic synthetic oils such as alkylnaphthalene, alkylbenzene, aromatic ester, etc. Or a mixture thereof can be exemplified.

[0013] The kinematic viscosity (mn ^ Zs) of the lubricating base oil at 100 ° C is not particularly limited, but is preferably 2 to 15 mm ² / s, more preferably 3 to 10 mm ² / s, more preferably 3 to 8 mm ² / s, and most preferably 3 to 6 mm ² / s. As a result, it is possible to obtain a lubricating oil composition that has sufficient oil film formation, excellent lubricity, and low evaporation loss.

[0014] The viscosity index (V I) of the lubricating base oil is not particularly limited, but is preferably 100 or more, more preferably 120 or more, and most preferably 130 or more. Thereby, the viscosity at low temperature can be reduced while securing an oil film at high temperature.

[0015] (A) Magnesium detergent

In the lubricating oil composition of the present invention, a detergent containing magnesium (hereinafter referred to as a magnesium detergent) is essential. Magnesium-based detergents are compounds that contain magnesium and are conventionally used in lubricating oil compositions as metal-based detergents. Can be used, and is not particularly limited. For example, magnesium sulfonate, magnesium sulfate, and magnesium salicylate. Of these, magnesium salicylate or magnesium sulfonate is particularly preferable. A magnesium type detergent may be used individually by 1 type, and may mix and use 2 or more types.

[0016] By containing a magnesium-based detergent as the component (A), it is possible to ensure high-temperature cleanability and antifungal properties required as a lubricating oil. Also, friction can be reduced, and therefore torque can be reduced. This is particularly advantageous in terms of fuel consumption characteristics.

[0017] The magnesium-based detergent has a magnesium concentration pMm [Mg] of 200 to 1 200 mass ppm, preferably 300 to 1100 mass ppm, more preferably, relative to the mass of the lubricating oil composition. It is added in an amount so as to be in the range of 400 to 1 000 mass p pm. If the amount of the magnesium detergent exceeds the above upper limit, the wear becomes excessive, and if it falls below the above lower limit, the friction reducing effect is low.

[0018] The magnesium-based detergent is particularly preferably overbased. This ensures the acid neutralization necessary for the lubricating oil. If overbased magnesium detergents are used, neutral magnesium or calcium detergents may be mixed.

[0019] The total base number of the magnesium-based detergent is not limited, but is preferably 20 to 600 mg KOH / g, more preferably 50 to 500 mg KOH g, and most preferably 100 to 45 Omg KOH / g. g. As a result, it is possible to ensure the acid neutralization, high temperature cleanliness, and mildew resistance required for the lubricant. When two or more kinds of metal detergents are mixed and used, the base number obtained by mixing is preferably in the above range.

[0020] The magnesium content in the magnesium-based detergent is preferably 0.5 to 20% by mass, more preferably 1 to 16% by mass, and most preferably 2 to 14% by mass. The lubricating oil composition contains the above amount of magnesium. It may be added as such.

[0021] When the lubricating oil composition of the present invention contains a molybdenum-based friction modifier described later, the amount of magnesium-based detergent is preferably the following formula (2):

[Mg] / [Mo] <2.5 (2) ([Mo] is the degree of spreading of molybdenum by mass p pm with respect to the mass of the lubricating oil composition ¾: indicated)

Meet.

The value of [Mg] / [Mo] is more preferably 2.0 or less, even more preferably 1.8 or less, and even more preferably 1.5 or less. If the value of the above equation (2) is equal to or greater than the above upper limit value, wear may become excessive. The lower limit of [Mg] / [Mo] is preferably 0.1, more preferably 0.2, and even more preferably 0.3.

[0022] The lubricating oil composition of the present invention may contain other metal detergent in addition to the magnesium detergent. The metal detergent may be any conventional one that has been used in conventional lubricating oil compositions. Preferably, a calcium-containing detergent (Α ′) is used in combination (hereinafter referred to as a calcium-based detergent). When the lubricating oil composition further contains a calcium-based detergent, it is possible to further ensure the high-temperature cleanability and antifungal properties necessary for the lubricating oil.

[0023] Calcium-based detergent (Α ') is a calcium-containing compound, which can be used as a metal-based detergent in the lubricating oil composition and is particularly limited. Not. Examples include calcium sulfonate, calcium sulfate and calcium salicylate. These calcium detergents may be used alone or in combination of two or more.

[0024] The amount of the component (Α ') preferably satisfies the following formula (1).

{[Mg] / ([Mg] + [C a])} X 1 00≥5 (1

)

Where [C a] is the mass of calcium relative to the mass of the lubricating oil composition pp The concentration by m is shown.

{[Mg] / ([Mg] + [C a])} The value of X 1 00 is more preferably 10 or more, and even more preferably 15 or more. If the value is less than the lower limit, the friction reducing effect is small. {[Mg] / ([Mg] + [Ca])} The upper limit of X 1 00 is preferably 100, more preferably 80, still more preferably 60, and most preferably 50.

[0025] Further, when the lubricating oil composition of the present invention contains a molybdenum-containing friction modifier described later, it is preferable that the following formula (3) is satisfied.

([Mg] + [C a]) / [Mo] ≤3.0 (3) where [Mo] is the concentration of molybdenum by mass p pm with respect to the mass of the lubricating oil composition.

The value of ([Mg] + [Ca]) / [Mo] is more preferably 2.8 or less, further preferably 2.6 or less, and particularly preferably 2.5 or less. If the above value exceeds the above upper limit, the torque reduction effect may be low. The lower limit of ([Mg] + [C a]) / [Mo] is preferably 0.2, more preferably 0.5, and even more preferably 1.0.

[0026] The calcium-based detergent (Α ') is preferably overbased. This ensures the acid neutralization necessary for the lubricating oil. If an overbased calcium-containing detergent is used, a neutral calcium detergent may be used in combination.

[0027] The total base number of the calcium detergent (Α ') is not limited, but is preferably 20 to 500 mg KOH / g, more preferably 50 to 400 mg KOH / 9, most preferably 100 to 350 m. _g KOH / _g . As a result, it is possible to ensure the acid neutralization, high-temperature cleanliness, and mildew resistance necessary for lubricating oil. When two or more kinds of metal detergents are used in combination, the base number obtained by mixing is preferably within the above range.

[0028] The calcium content in the calcium detergent (清浄 ') is preferably 0.5 to 20% by mass, more preferably 1 to 16% by mass, and most preferably 2 to 14% by mass. It is. [0029] The lubricating oil composition of the present invention may contain a sodium-based detergent as a metal-based detergent other than those described above as long as the effects of the present invention are not impaired. The sodium-based detergent is a compound having sodium, and for example, sodium sulfonate, sodium phenate, and sodium tumulisylate are preferable. One of these sodium detergents may be used alone, or two or more thereof may be mixed and used. By including a sodium-based detergent, it is possible to ensure the high-temperature cleanliness and antifungal properties necessary as a lubricating oil. The sodium detergent can be used in combination with the magnesium detergent and optional calcium detergent described above.

[0030] The total amount of the metallic detergent in the lubricating oil composition of the present invention may be such that the amount of magnesium contained in the composition satisfies the specific range described above. Depending on the amount of magnesium detergent, the amount of calcium detergent and sodium detergent added may be limited.

[0031] (B) Compound having boron

The lubricating oil composition of the present invention comprises a compound having boron. The compound having boron may be a known compound that has been conventionally blended in a lubricating oil composition. A typical boron-containing compound is a boron-containing ashless dispersant. Other boron-containing compounds include alkali borate additives described later. Among these, a boron-containing ashless dispersant is preferable, and the lubricating oil composition of the present invention particularly contains one or more boron-containing ashless dispersants as a compound having boron.

[0032] In the lubricating oil composition of the present invention, the amount of boron contained in the composition is 100 to 300 ppm by mass as the concentration by the mass P pm of boron relative to the total mass of the composition. Features. The boron content is more preferably from 120 to 2800 mass ppm, most preferably from 1550 to 2500 mass ppm. Accordingly, the boron-containing compound, particularly the boron-containing ashless dispersant, is blended in such an amount that the amount of boron contained in the composition satisfies the above range. When using a boron-containing ashless dispersant in combination with other boron-containing compounds, The total amount of silicon is adjusted to satisfy the above range. Particularly, the amount of boron-containing ashless dispersant, 0.1 to 5 wt% of the total amount of the composition, preferably 0.3 to 4 mass ^_0/0, more preferably 0.5 to 3 mass ^_0/0 It is good to be.

[0033] The boron-containing ashless dispersant may be any conventionally known one, and may be used alone or in combination of two or more. For example, a succinic acid imide compound modified with a boron compound such as boric acid or borate (borated) can be used. Further, the lubricating oil composition of the present invention may further contain an ashless dispersant containing no boron. When a boron-containing ashless dispersant and a boron-free ashless dispersant are used in combination, the total amount of the ashless dispersant is 20% by mass or less, preferably 15% by mass or less, more preferably 1 based on the total amount of the composition. 0 wt% or less, as long and most preferably rather 5 mass ^_0/0 or less.

[0034] Examples of known ashless dispersants include, for example, at least one linear or branched alkyl group or alkenyl group having 40 to 500, preferably 60 to 35, carbon atoms in the molecule. A nitrogen-containing compound or derivative thereof, a Mannich dispersant, or a monotype or bistype succinic acid derivative (for example, a compound having a structure of an alkenyl succinimide), an alcohol having 40 to 50 carbon atoms Benzylamine having at least one kill group or alkenyl group in the molecule, or a polyamine having at least one alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule, or a boron compound, carboxylic acid, Examples include modified products such as phosphoric acid. One type or two or more types arbitrarily selected from these can be blended. The boron-containing ashless dispersant is a compound obtained by modifying the above compound with a boron compound. In particular, monotype or bis type succinic acid imide derivatives, more particularly alkenyl succinic acid imide compounds modified with boron compounds such as boric acid or borates (borated) are preferred.

[0035] The boronated succinic acid derivative is produced by a known method and is not particularly limited. For example, a mono-type or bis-type succinic acid imide derivative is a compound having an alkyl group or an alkenyl group having 40 to 500 carbon atoms. The compound is reacted with maleic anhydride at 100 to 200 ° C. to produce an alkyl succinic acid or alkenyl succinic acid, and obtained by reacting the alkyl succinic acid or alkenyl succinic acid with a polyamine. It is done. Here, examples of the polyamine include diethylene polyamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine. The monotype succinimide derivative can be represented by, for example, the following formula (a). The bis-type succinimide derivative can be represented by, for example, the following formula (b).

[0036] [Chemical 1]

[0037] [Chemical 2]

In the above formula, R ¹ is independently an alkyl group or alkenyl group having 40 to 40 carbon atoms, m is an integer of 1 to 20 and n is an integer of 0 to 20. A bis-type succinic acid imide compound is particularly preferable. The succinic acid imide derivative may be a combination of a monotype and a bistype, a combination of two or more monotypes, or a combination of two or more bistypes.

By reacting the succinic acid derivative with a boron compound, a fluorinated succinic acid imide derivative is obtained. Boron compound is boric acid Boric anhydride, boric acid ester, boron oxide, and boron halide. The boronated succinimide derivative may be used alone or in combination of two or more.

[0039] As other ashless dispersants, derivatives of nitrogen-containing compounds are known. For example, the above-mentioned nitrogen-containing compound (that is, having at least one linear or branched alkyl group or alkenyl group having 40 to 500, preferably 60 to 35, carbon atoms in the molecule) Nitrogen-containing compounds) and monocarboxylic rubonic acids such as fatty acids with 1 to 30 carbon atoms, polycarboxylic acids with 2 to 30 carbon atoms such as oxalic acid, phthalic acid, trimellitic acid, pyromellitic acid, or the like Anhydrous anhydride or ester compound, alkylene oxide having 2 to 6 carbon atoms, and hydroxy (poly) oxyalkylene carbonate are reacted to neutralize part or all of the remaining amino groups and / or imino groups Or amidated modified compounds with so-called oxygen-containing organic compounds; boric acid was allowed to act on the aforementioned nitrogen-containing compounds to neutralize some or all of the remaining amino groups and / or imino groups A so-called boron-modified compound that has been amidated; phosphoric acid is allowed to act on the nitrogen-containing compound described above to neutralize or amid all or part of the remaining amino group and / or imino group, A so-called phosphoric acid-modified compound; a sulfur-modified compound obtained by allowing a sulfur compound to act on the above-mentioned nitrogen-containing compound; and the above-mentioned nitrogen-containing compound selected from oxygen-modified organic compounds, boron-modified, phosphoric acid-modified, sulfur-modified 2 Examples include modified compounds that combine more than one type of modification.

[0040] Among known ashless dispersants, boric acid-modified compounds of the above-mentioned alkenyl succinic acid imide derivatives, particularly boric acid-modified compounds of the bis-type alkenyl succinimide derivatives are heat-resistant when used in combination with the above base oil. This is preferable because the properties can be further improved.

[0041] The number average molecular weight (M n) of the ashless dispersant is preferably, but not limited to, 20.00 or more, more preferably 2500 or more, and even more preferably 30000 or more. Most preferably, it is at least 500,000, and preferably at most 1,500. If the number average molecular weight of the ashless dispersant is less than the above lower limit, The dispersibility may not be sufficient. On the other hand, if the number average molecular weight of the ashless dispersant exceeds the above upper limit, the viscosity is too high and the fluidity becomes insufficient, which may cause an increase in deposit.

[0042] As another boron-containing compound, an alkali borate additive can be added. The alkali borate additive contains an alkali metal borate hydrate and can be represented by the following general formula.

M ₂ 0 XB ₂ 0 ₃ y H ₂ 0

In the above formula, M is an alkali metal, X is 2.5 to 4.5, and y is 1.0 to 4.8.

Examples include lithium borate hydrate, sodium borate hydrate, lithium borate hydrate, rubidium borate hydrate and cesium folate hydrate. Rium hydrate and sodium borate hydrate are preferred, and potassium borate hydrate is particularly preferred. The average particle size of the alkali metal borate hydrate particles is generally less than ミクロン microns (xm). In the aluminum borohydride hydrate used in the present invention, the ratio of boron to aluminum borohydride is preferably in the range of about 2.5: 1 to 4.5: 1. The addition amount of the alkali borate-based additive is 2 to 300 mass ppm as the boron amount based on the total amount of the lubricating oil composition.

[0043] Further, other boron-containing compounds include potassium metaborate, potassium tetraborate, potassium pentaborate, potassium hexaborate, potassium octaborate and the like, such as lithium borate, calcium borate sulfonate, and boron. Calcium acid salicylate, etc.

[0044] (C) Zinc dialkyldithiophosphate

The lubricating oil composition of the present invention contains dialkyldithidium zinc phosphate (ZnDTP (also referred to as ZDDP)). The compound functions as an antiwear agent and is represented by the following formula (4).

[0045] [Chemical 3]

In the above formula (4), ² and ³ may be the same as or different from each other, and are a hydrogen atom or a monovalent hydrocarbon group having 1 to 26 carbon atoms. Monovalent hydrocarbon groups include primary (primary one) or secondary (secondary one) alkyl groups having 1 to 26 carbon atoms; alkenyl groups having 2 to 26 carbon atoms; 6 to 26 carbon atoms. A cycloalkyl group; an aryl group having 6 to 26 carbon atoms, an alkylaryl group or an arylalkyl group; or a hydrocarbon group containing an ester bond, an ether bond, an alcohol group or a carboxyl group. Here, the primary alkyl group means that in the substituents R ² and R ³ , the carbon atom directly bonded to the oxygen atom in the zinc dialkyldithiophosphate is a primary carbon atom. Similarly, the secondary alkyl group means that in the substituents R ² and R ³ , the carbon atom directly bonded to the oxygen atom in the zinc dialkyldithiolate is a secondary carbon atom. ² and (^ ³ are preferably independently of each other a primary or secondary alkyl group having 3 to 12 carbon atoms, a cycloalkyl group having 8 to 18 carbon atoms, or 8 to 18 carbon atoms. However, in the present invention, at least one of R ² and R ³ is a primary or secondary alkyl group, and the primary alkyl group has 3 to 12 carbon atoms. Preferably having 4 to 10 carbon atoms, for example, propyl group, butyl group, pentyl group, hexyl group, decyl group, nonyl group, decyl group, dodecyl group, 2-ethyl-hexyl And a 2,5-dimethylhexyl group, etc. The secondary alkyl group preferably has 3 to 12 carbon atoms, more preferably 3 to 10 carbon atoms. Isopropyl group, secondary butyl group, iso pen Group, and cyclohexyl group, and the like to the I source. [0047] The lubricating oil composition of the present invention contains one or more selected from zinc dialkyldithiophosphates having a primary alkyl group and / or a secondary alkyl group. However, zinc dialkyldithiophosphate having a secondary alkyl group must be included. That is, the lubricating oil composition of the present invention comprises a first embodiment comprising a zinc dialkyldithiophosphate having a primary alkyl group and a zinc dialkyldithiophosphate having a secondary alkyl group. A second embodiment comprising zinc dialkyldithiophosphate having both a group and a secondary alkyl group, or a zinc dialkyldithiophosphate having a primary alkyl group comprising a zinc dialkyldithiophosphate having a secondary alkyl group There is no third aspect. Preferred are the first and third embodiments, and particularly preferred is the first embodiment in which a zinc dialkyldithiophosphate having a primary alkyl group and a zinc dialkyldithiophosphate having a secondary alkyl group are used in combination. . If zinc dialkyldithiophosphate having a secondary alkyl group is not contained, good wear resistance cannot be secured. The lubricating oil composition of the present invention comprises a zinc dialkyldithiophosphate having a primary alkyl group and a zinc dialkyldithiophosphate having a secondary alkyl group having a ratio (mass) of 70:30 to 0: 1100. It is contained so as to satisfy the range of. The range is preferably 65:35 to 5:95, more preferably 60:40 to 10:90, particularly preferably 50:50 to 20:80. If the content ratio of the zinc dialkyldithiophosphate having a primary alkyl group exceeds the above upper limit, the wear resistance may be deteriorated, which is not preferable.

[0048] The content of zinc dialkyldithiophosphate in the lubricating oil composition is such that the concentration [P] due to the phosphorus mass p pm of the dialkyldithidium zinc phosphate with respect to the total mass of the lubricating oil composition is 300 to The amount is 1 000 mass p pm, preferably 400 to 1,000 mass p pm, more preferably 500 to 1,000 mass p pm, and particularly preferably 600 to 900 mass p pm.

[0049] The present invention relates to the amount of boron, zinc dialkyldithiophosphate having a primary alkyl group (hereinafter simply referred to as primary) and secondary contained in the lubricating oil composition. The torque reduction rate is improved by adjusting the relationship (combination) with the mass ratio of the dialkyl dititanium phosphate having an alkyl group (hereinafter simply referred to as “secondary”). The combination is such that the boron amount relative to the total amount of the composition is 100 to 300 mass, preferably 120 to 280 mass p pm, particularly preferably 150 to 250 mass p pm, and dialkyldithioline The composition of zinc acid has a primary to secondary mass ratio of 70:30 to 0: 100, preferably 65:35 to 5:95, more preferably 60:40 to 10:90, particularly preferably It may be appropriately adjusted within a range satisfying 50:50 to 20:80. Incidentally, the total amount of zinc dialkyldithiophosphate may satisfy the above range as the total mass ppm of phosphorus. The lubricating oil composition thus obtained can achieve both good anti-friction properties and anti-wear properties even when the viscosity is lowered.

[0050] The lubricating oil composition of the present invention may further contain an antiwear agent other than the dialkyldithidium zinc phosphate. For example, represented by the above formula, is ² and 8 ^3, the independent one another, a hydrogen atom or a number of〗 to 26 carbon atoms, compounds are monovalent hydrocarbon groups which are not an alkyl group. Examples of the monovalent hydrocarbon group include an alkenyl group having 2 to 26 carbon atoms; a cycloalkyl group having 6 to 26 carbon atoms; an aryl group having 6 to 26 carbon atoms, an alkylaryl group, or an arylalkyl group; Or an ester bond, an ether bond, an alcohol group or a hydrocarbon group containing a carboxyl group. R ² and R ³ are preferably a cycloalkyl group having 8 to 18 carbon atoms and an alkylaryl group having 8 to 18 carbon atoms, and may be the same as or different from each other. In addition, dichi talented zinc rubamate (Zn DTC) may be used in combination.

[0051] In addition, at least one compound selected from phosphates represented by the following formulas (5) and (6), phosphate phosphorus compounds, and metal salts and amine salts thereof may be used in combination.

[0052] [Chemical 4]

RHo— ^p one o—R ⁵

[0053] In the general formula (5), R ⁶ is a monovalent hydrocarbon group having a carbon number of〗 to 30; R ⁴ and R ⁵ are each independently a hydrogen atom or a monovalent carbon of 1 to 30 carbon atoms. It is a hydrogen group, and k is 0 or 1.

[0054] [Chemical 5]

0

R ⁹ -(-0 j ~ P 1 0 1 R ⁸

0 one (6)

[0055] In the general formula (6), R ⁹ is a monovalent hydrocarbon group having a carbon number of〗 to 30; R ⁷ and R ⁸ are each independently a hydrogen atom or a monovalent hydrocarbon of 1 to 30 carbon atoms. And t is 0 or 1.

In the above general formulas (5) and (6), examples of the monovalent hydrocarbon group having 1 to 30 carbon atoms represented by R ⁴ to R ⁹ include an alkyl group, a cycloalkyl group, and an alkenyl group. An alkyl-substituted cycloalkyl group, an aryl group, an alkyl-substituted aryl group, and an aryl alkyl group. In particular, an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 24 carbon atoms is preferable, more preferably an alkyl group having 3 to 18 carbon atoms, and most preferably 4 to 15 carbon atoms. It is an alkyl group.

[0057] Examples of the phosphorus compound represented by the general formula (5) include phosphorous acid monoester having one hydrocarbon group having 1 to 30 carbon atoms and (hydrocarbyl) phosphonous acid; Phosphorous acid diester having two hydrocarbon groups of 1 to 30, monodivalent phosphite diester, and (hydrocarbyl) phosphite Phosphonic acid monoesters; phosphorous acid triesters having three hydrocarbon groups having 1 to 30 carbon atoms, and (hydrocarbyl) phosphonous acid diesters; and mixtures thereof.

[0058] The metal salt or amine salt of the phosphorus compound represented by the general formula (5) or (6) is obtained by adding a metal oxide or metal water to the phosphorus compound represented by the general formula (5) or (6). Works with metal bases such as oxides, metal carbonates, metal chlorides, ammonia, nitrogen compounds such as amine compounds having only hydrocarbon groups with 1 to 30 carbon atoms or hydroxyl group-containing hydrocarbon groups in the molecule And by neutralizing part or all of the remaining acidic hydrogen. Examples of the metal in the metal base include alkaline metals such as lithium, sodium, potassium, and cesium, alkaline earth metals such as calcium, magnesium, and barium, zinc, copper, iron, lead, nickel, silver, and manganese. Heavy metals (excluding molybdenum). Among these, alkaline earth metals such as calcium and magnesium and zinc are preferable, and zinc is particularly preferable.

[0059] The amount of zinc dialkyldithiophosphate may be added so that the phosphorus content derived from zinc dialkyldithiophosphate falls within the specific range described above. When other anti-wear agents are included, the total amount of anti-wear agents including dialkyldithidium zinc phosphate is usually 0.1 to 5% by mass, preferably 0.2 to 3% by mass in the lubricating oil composition. . It may be blended with / ₀ .

[0060] The lubricating oil composition of the present invention may contain various conventionally known additives as optional components in addition to the components described above. For example, a molybdenum-based friction modifier or a viscosity index improver can be included.

[0061] Molybdenum friction modifier

A friction modifier having molybdenum (hereinafter referred to as a molybdenum friction modifier) is not particularly limited, and conventionally known friction modifiers can be used. Molybdenum-based friction modifiers are compounds containing molybdenum, for example, organic molybdenum compounds containing sulfur such as molybdenum diphosphate phosphate (M o DTP) and molybdenum dithiode talent (M o DTC), molybdenum Compound and sulfur Examples thereof include complexes with yellow-containing organic compounds or other organic compounds, and complexes of sulfur-containing molybdenum compounds such as molybdenum sulfide and sulfurized molybdenum acid with alkenyl succinic acid imide. Examples of the molybdenum compounds include molybdenum oxides such as molybdenum dioxide and molybdenum trioxide, molybdenum acids such as orthomolybdic acid, paramolybdic acid and (poly) sulfurized molybdic acid, and molybdenum such as metal salts and ammonium salts of these molybdic acids. Molybdenum sulfides such as acid salts, molybdenum disulfide, molybdenum trisulfide, molybdenum pentasulfide and polysulfide molybdenum, metal salts or amine salts of molybdenum sulfide, sulfurized molybdenum acid, and molybdenum halides such as molybdenum chloride . Examples of the sulfur-containing organic compounds include alkyl (x) xanthate, thiadiazol, mercapto thiadiazol, chi talent -bonate, tetrahydracarbylthiuram disulfide, bis (di (chi)) hydrocar 1) Disulfide, organic (poly) sulfide, and sulfurized ester. In particular, Molybdenum Ziichi phosphate (Mo DTP) and Molybdenum Zizi talent (Mo DT

Organic molybdenum compounds such as C) are preferred.

[C062] Molybdenum dithiophosphate (Mo DTC) is a compound represented by the following formula [I], and molybdenum dithiophosphate (Mo DTP) is [I I

] It is a compound represented by these.

[0063] [Chemical 6]

[0064] [Chemical 7]

[0065] In the above general formula [门and [I门, R, ~ R _8, which may be different also identical der connexion to each other, is a monovalent hydrocarbon group having 1 to 3 0 carbon atoms. The hydrocarbon group may be linear or branched. The -valent hydrocarbon group includes a linear or branched alkyl group having 1 to 30 carbon atoms; an alkenyl group having 2 to 30 carbon atoms; a cycloalkyl group having 4 to 30 carbon atoms; and 6 to 6 carbon atoms. An aryl group, an alkyl group or an arylalkyl group of 30 can be exemplified. In the aryl alkyl group, the bonding position of the alkyl group is arbitrary. 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, a decyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, Examples thereof include a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, and the like, and branched alkyl groups thereof. Particularly, an alkyl group having 3 to 8 carbon atoms is preferable. X and X ₂ are oxygen atoms or sulfur atoms, and Y ₂ is an oxygen atom or sulfur atom.

[0066] An organic molybdenum compound containing no sulfur can also be used as a friction modifier.

Examples of such compounds include molybdenum monoamine complexes, molybdenum-succinic acid imide complexes, molybdenum salts of organic acids, and molybdenum salts of alcohols.

[0067] Further, as a friction modifier in the present invention, a trinuclear molybdenum compound described in US Pat. No. 5,90,6,968 can also be used.

[0068] The friction modifier has a concentration [M o] in terms of ppm by mass of molybdenum with respect to the mass of the lubricating oil composition of 5 00 to 1 5 0 0 mass 卩卩 01, preferably 6 0 to 1 2 It is added in such an amount that the range is 00 mass p pm. If the amount of the friction modifier exceeds the above upper limit, the cleanliness may be deteriorated. If the amount is less than the above lower limit, the friction may not be sufficiently reduced, or the cleanliness may be deteriorated. is there.

[0069] As described above for the component (A), the friction modifier is preferably represented by the following formula:

2):

[Mg] / [Mo] Ku 2.5 (2)

Included in an amount that satisfies. [Mo] is the concentration due to the mass P pm of molybdenum relative to the mass of the lubricating oil composition.

The value of [Mg] [Mo] is more preferably 2.0 or less, even more preferably 1.8 or less, and even more preferably 1.5 or less. The lower limit of [Mg] / [Mo:] is preferably 0.1, more preferably 0.2, and even more preferably 0.3.

[0070] Viscosity index improver

Examples of viscosity index improvers include polymethacrylates, dispersed polymethacrylates, olefin copolymers (polyisobutylene, ethylene-propylene copolymers), dispersed-type olefin copolymers, polyalkylstyrene, styrene-butadiene hydrogenated. Examples include copolymers, styrene monomaleic anhydride ester copolymers, and star-shaped isoprene. Further, a comb polymer containing at least a repeating unit based on a polyolefin macromolecule and a repeating unit based on an alkyl (meth) acrylate having an alkyl group having 1 to 30 carbon atoms in the main chain can be used.

[0071] The viscosity index improver usually comprises the polymer and a diluent oil. The content of the viscosity index improver is preferably from 0.01 to 20% by mass, more preferably from 0.02 to 10% by mass, and most preferably from 0.05 to 5% as a polymer amount based on the total amount of the composition. Mass%. If the content of the viscosity index improver is less than the lower limit, the viscosity temperature characteristics and the low temperature viscosity characteristics may be deteriorated. On the other hand, if it exceeds the above upper limit, the viscosity temperature characteristics and the low temperature viscosity characteristics may deteriorate. In addition, product costs will rise significantly.

[0072] The lubricating oil composition of the present invention may further contain other additives depending on the purpose in order to improve its performance. As other additives, those generally used in lubricating oil compositions can be used. For example, antioxidants, other friction modifiers, corrosion inhibitors, antifungal agents, pour point depressants, Examples thereof include additives such as demulsifiers, metal deactivators and antifoaming agents.

[0073] Examples of the antioxidant include ashless antioxidants such as phenols and amines, and metal-based antioxidants such as copper and molybdenum. For example, phenolic ashless antioxidants include 4,4'-methylenebis (2,6-di-tert-butylphenol), 4,4'-monobis (2,6-di-tert-butylphenol), isooctyl-3. — (3,5-Gi t petit laur 4-hydroxyphenyl) Propionate, etc., and amine-based ashless antioxidants include phenyl α-naphthylamine, alkyl phenyl α-naphthylamine, dialkyldiphenylamine, etc. Can be mentioned. The antioxidant is usually blended in the lubricating oil composition at 0.1 to 5% by mass.

[0074] Examples of the friction modifier other than the above include esters, amines, amides, sulfurized esters and the like. The friction modifier is usually blended in the lubricating oil composition at a concentration of 0.01 to 3% by mass.

[0075] Examples of the corrosion inhibitor include benzotriazole-based, silyl-triazole-based, thiadiazol-based, and imidazole-based compounds. Examples of the antifungal agent include petroleum sulfonate, alkylbenzene sulfonate, dinonyl naphthalene sulfonate, alkenyl succinate, polyhydric alcohol ester and the like. The corrosion inhibitor and the antifungal agent are usually blended in the lubricating oil composition in an amount of 0.01 to 5% by mass, respectively.

[0076] As the pour point depressant, for example, a polymethacrylate polymer compatible with the lubricating base oil to be used can be used. The pour point depressant is usually placed in the lubricating oil composition at from 0.01 to 3% by weight.

[0077] Examples of the demulsifier include polyoxyethylene alkyl ether, Examples thereof include polyalkylene glycol-based nonionic surfactants such as poly-xoxyethylene alkyl phenyl ether and poly-xoxyethylene alkyl naphthyl ether. The demulsifier is usually blended in the lubricating oil composition in an amount of 0.01 to 5% by mass.

[0078] Examples of the metal deactivator include imidazoline, pyrimidine derivatives, alkyl thiadiazoles, mercaptobenzozoazoles, benzoxiazool or derivatives thereof, 1, 3, 4-thiadiazol polysulfide. 1,3-, 4-thiadiazoliru 2,5-bisdialkyldithiocarbamate, 2- (alkyldithio) benzoimidazole, / 3- (o-carboxybenzylthio) propiononitrile, and the like. The metal deactivator is usually blended in the lubricating oil composition at 0.01 to 3 mass%.

[0079] As the defoaming agent, for example, 25 kinematic viscosity at C is 1 000 to 1 00,000 mm ² / s of silicone oil, alkenylsuccinic acid derivatives, esters of polyhydroxy aliphatic alcohols and long chain fatty acids, Mechirusarichire First, and o-hydroxybenzyl alcohol. Defoamers are typically added in a 0.00 1-1 mass ^_0/0 in the lubricating oil composition.

[0080] The CCS viscosity of the lubricating oil composition of the present invention at 35 ° C is not limited, but is preferably 6.2 Pa · s or less, more preferably 5.0 Pa · s or less, and even more preferably. Or 4.0 Pa · s or less, and most preferably 3.5 Pa or less.

[0081] When the lubricating oil composition of the present invention contains molybdenum, the amount of molybdenum contained in the lubricating oil composition and the CCS viscosity at 35 ° C satisfy the following formula (7): It is preferable.

[CCS viscosity] / [Mo] O. 0 1 (7)

([CCS Viscosity] indicates the value of CCS viscosity (P a-s) at 35 ° C of the lubricating oil composition, and [Mo] indicates the concentration of molybdenum by p pm relative to the mass of the lubricating oil composition. )

The value of [CCS viscosity] / [Mo] is more preferably 0.008 or less, and further preferably 0.005 or less. When the above value exceeds 0.0 1, the torque is low. Decrease rate may decrease or cleanliness may deteriorate. The lower limit value of [CCS viscosity] / [Mo] is not limited, but is preferably 0.002 and more preferably 0.003.

[0082] The high temperature high shear viscosity (HTHS viscosity) at 150 ° C of the lubricating oil composition of the present invention is not limited, but is 1.5 to 2.9 mPa's, preferably 1.7 to 2.8. m P a s, more preferably 2.0 to 2.6 m Pa s.

[0083] The kinematic viscosity at 100 ° C of the lubricating oil composition of the present invention is not limited, but is preferably less than 9.3 mm ² / s, more preferably less than 8.2 mm ² / s.

[0084] The lubricating oil composition of the present invention has sufficient frictional characteristics and wear characteristics even when the viscosity is low, and has the effect of obtaining a high torque reduction rate. It can be suitably used for a gasoline engine

Example

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[0086] Materials used in Examples and Comparative Examples are as follows.

Lubricating base oil

GT L base oil (kinematic viscosity at 100 ° C = 4.1 mm ² / s VI = 1 27)

[0087] (A) Magnesium detergent

Magnesium sulfonate (total base number 400 mg KO HZg, magnesium content 9.4% by mass)

(Α ') Calcium-based detergent

Calcium salicylate (total base number 230 mg KO H / g, calcium content 5.5% by mass)

[0088] (B) Ashless dispersant containing boron

Boronated succinic acid imide compound (represented by the above formula (b), R ¹ is polybutenyl, n = 4 to 12 mixture, boron content 0.7 mass%, nitrogen content 2. (0% by mass) [0089] (Β ') Ashless dispersant without boron

Represented by succinic acid imide compound (above-mentioned formula (b), R ¹ is polybutenyl, mixture of _n =. 4 to 1 2, boron content 0 wt%, nitrogen content 1.0 mass ^_0/0 )

[0090] (C) Antiwear agent 1

P ri — Z n DT P (compound represented by the following formula (4), wherein R ² and R ³ are both primary alkyl groups having 8 carbon atoms)

[0091] [Chemical 8]

[0092] (C) Antiwear agent 2

S ec -Z n DT P (compound represented by the above formula (4), wherein R ² is a secondary alkyl group having 4 carbon atoms and R ³ is a secondary alkyl group having 6 carbon atoms)

[0093] (D) Friction modifier

Molybdenum friction modifier: Mo DTC (Molybdenum content: 10% by mass)

[0094] (E) Viscosity index improver

Polymethacrylate

[0095] Other additives

Antioxidant: Fu: Knoll-based antioxidant

Antifoaming agent: dimethyl silicone

[0096] Examples 1 to 8 and Comparative Examples 1 to 6

Lubricating oil compositions were prepared by mixing the components in the amounts shown in Tables 1 and 3. The parts by mass shown in the table are parts by mass relative to the total amount (100 parts by mass) of the lubricating oil composition. The amounts of (A) magnesium-based detergent, (Α ') calcium-based detergent, and (D) molybdenum-based friction modifier listed in the table are magnesium, calcium It is the mass P pm (in order [Mg], [C a], and [Mo]) with respect to the total amount of the lubricating oil composition in terms of the contents of sulfur and molybdenum. [B] shown in the table is the mass P pm of boron with respect to the total amount of the lubricating oil composition. (C) A total of 1 part by mass of the antiwear agent was combined with the total amount of the lubricating oil composition (100 parts by mass). The table shows that 1 part by weight of the antiwear agent 1 (dialkyldithiodizinc phosphate having a primary alkyl group) and antiwear agent 2 (zinc dialkyldithiophosphate having a secondary alkyl group) The mass ratio (first class, second class (mass ratio)) is described. [P] in the table is the mass of phosphorus p pm relative to the total amount of the lubricating oil composition. The amounts of magnesium-based detergent and calcium-based detergent were set so that the total molar amount of magnesium and calcium contained in these detergents was as identical as possible in all examples and comparative examples.

[0097] The following tests were performed on the obtained compositions. The results are shown in Tables 2 and 4.

[0098] (1) 1 High temperature high shear viscosity at 50 ° C (HTHS 1 50)

Measured according to ASTM D4683.

[0099] (2) CCS viscosity at 35 ° C (CCS viscosity)

Measured according to A S TMD 5293.

[0100] (3) Kinematic viscosity at 1 00 ° C (K V 1 00)

It was measured at 100 ° C according to ASTMD445.

[0101] (4) Torque reduction rate

The lubricating oil compositions obtained in Examples and Comparative Examples were used as test compositions, and torque was measured in a motoring test using a gasoline engine. The engine is a Toyota 2ZR—FE 1. 8 L in-line four-cylinder engine, and a torque meter is installed between the motor and the engine to measure the torque at an oil temperature of 80 ° C and an engine speed of 700 RPM. did. Torque was measured in the same manner using commercially available GF- 50W-20 oil as a standard oil. The torque (T) of the test composition is compared with the torque of the standard oil (T ₀ ), and the reduction rate from the torque of the standard oil ({(T. One T) / T _Q } X 1 00) (%) Calculated. The larger the reduction rate, the better the fuel consumption. Show. A reduction rate of 9.0% or more was accepted.

[0102] (5) Shell wear scar diameter

The measurement was performed according to the shell four-ball test (ASTMD4 1 72) except that the number of revolutions was 1 800 rpm, the load was 40 kgf, the test temperature was 90 ° C, and the test time was 30 minutes. Those with wear scar diameters of 0.7 mm or less were accepted.

[0103] (6) Hot tube test (Evaluation of high temperature cleanliness)

The lubricating oil composition was allowed to flow through a glass tube having an inner diameter of 2 mm at 0.3 ml Z, air at 10 milliliters per second, and the glass tube temperature at 270 ° C. for 16 hours. The lacquer adhering to the glass tube was compared with the color sample, and the score was assigned as 10 for transparent and 0 for black. Higher scores indicate better hot cleanliness. A score of 4.5 or higher was accepted.

[0104]

table

Composition Example 1 Example 2 Example 3 Example 4 Example 5 Actual] [Lubricant base oil remainder remaining remainder remaining residue remaining

[A] Mg-based purifier [Mg] 400 500 600 400 400

[Α ·] Ca-based detergent [Ca] 1400 L400 1100 1400 1400 Boron-containing quality! : Part 3 3 3 1.5 4.5

[Β]

Ashless dispersant [B] 200 200 200 100 300 No boron

[ΒΊ Mass part 0 0 0 1.6 0

Ashless dispersant

Primary alkyl group

Contained by weight 0.5 0 0.5 0.5 0 Antiwear agent 1

Secondary alkyl group

[C] Contained mass part 0.5 1 0.5 0.5 1

Antiwear agent 2

Level 1 / Level 2

50/50 0/100 50/50 50/50 0/100 5 (mass ratio)

Total [P] 800 800 800 800 800

[D] Friction adjustment [o] 800 800 800 800 800

[Ε] Viscosity index improver Mass parts 8 8 8 8 8

Other additives Mass parts 2 2 2 2 2

([Mg] / ([Mg] + [Ca])} XIOO 22 26 35 22 22.

([Mg] + [Ca]) / [Mo] 2.3 2.4 2.1 2.3 2.3

[Mg] 1 [Mo] 0.50 0.63 0.75 0.50 0.50

[]

Table 2

table

] [

圖

[0108] As shown in Table 2, although the lubricating oil composition of the present invention has low kinematic viscosity at 100 ° C, it has low wear, and has a high torque reduction rate and high temperature cleanliness. Yes.

Industrial applicability

[0109] The lubricating oil composition of the present invention has an effect that, even when the viscosity is lowered, it is possible to reduce friction while ensuring wear resistance and to obtain a high torque reduction rate. As a preferred embodiment, it is suitable as a lubricating oil composition for an internal combustion engine, and further as a lubricating oil composition for a supercharged gasoline engine.

Claims

The scope of the claims

[Claim 1] A lubricating oil composition comprising a lubricant base oil, (A) a detergent having magnesium, (B) a compound having boron, and (C) a zinc dialkyldizinc phosphate.

(A) The amount of the component is in the range of 200 to 1 200 mass p pm as the concentration [Mg] of magnesium mass p pm with respect to the mass of the lubricating oil composition,

The amount of the component (C) is in the range of 300 to 1,000 mass p pm as the concentration [P] of the phosphorus mass p pm with respect to the mass of the lubricating oil composition, and the component (C) is a primary alkyl 1 or more selected from a dialkyldithiophosphate zinc having a group and / or a secondary alkyl group, provided that the lubricating oil composition contains at least one zinc dialkyldithiophosphate having a secondary alkyl group, The ratio (mass ratio) of the dialkyl dithiophosphate zinc having a secondary alkyl group and the dialkyl dithiophosphate zinc having a secondary alkyl group is in the range of 70:30 to 0: 100, and the ratio of boron to the mass of the lubricating oil composition A lubricating oil composition characterized in that the concentration [B] by mass P pm is in the range of 100 to 300 mass p pm.

[Claim 2] (B) An ashless dispersant having boron as a compound having boron

The lubricating oil composition according to claim 1, comprising one or more.

[Claim 3] Further comprising a detergent (Α ') having calcium, wherein the following formula (1):

{[Mg] / ([Mg] + [C a])} X 1 00≥ 5

([C a] indicates the concentration by the calcium mass p pm relative to the mass of the lubricating oil composition)

The lubricating oil composition according to claim 1 or 2, wherein:

[Claim 4] Further includes a friction modifier having molybdenum, and the following formula (2): ([Mo] indicates the concentration of molybdenum by p pm relative to the mass of the lubricating oil composition)

4. The lubricating oil composition according to any one of claims 1 to 3, wherein:

[Claim 5] The CCS viscosity at 35 ° C is 6.2 Pa · s or less.

5. The lubricating oil composition according to any one of 4 above.

[Claim 6] The lubricating oil composition according to any one of claims 1 to 5, wherein the high temperature high shear viscosity (HTHS viscosity) at 1 50 ° C is 1.5 to 2.9 mPas. object

[Claim 7] The lubricating oil composition according to any one of claims 1 and 6, wherein the kinematic viscosity at 100 ° C is less than 9.3 mm ² / s.

[Claim 8] The lubricating oil composition according to any one of claims 1 to 7, which is used for an internal combustion engine.