WO2018021559A1

WO2018021559A1 - Lubricant composition

Info

Publication number: WO2018021559A1
Application number: PCT/JP2017/027544
Authority: WO
Inventors: 康小野寺; 鈴木　寛之; 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; トヨタ自動車株式会社
Priority date: 2016-07-29
Filing date: 2017-07-28
Publication date: 2018-02-01
Also published as: CN109844080A; US20190169520A1; EP3492568A4; EP3492568A1; JP6730123B2; JP2018016762A

Abstract

Provided is a lubricant composition which is capable of reducing friction, while ensuring anti-wear properties even if the viscosity thereof is decreased. A lubricant composition which contains a lubricant base oil, (A1) a metal salicylate and (B) a molybdenum-based friction regulator, and which is characterized in that: the amount of the component (B) is 500 to 1,500 ppm by mass in terms of the molybdenum concentration [B] in the lubricant composition; the component (A1) is calcium salicylate, magnesium salicylate or a combination thereof; the calcium concentration [Ca] based on the calcium salicylate in the lubricant composition is 0 to 1,800 ppm by mass; the magnesium concentration [Mg] based on the magnesium salicylate in the lubricant composition is 0 to 1,800 ppm by mass; and the total of the calcium concentration [Ca] and the magnesium concentration [Mg] is 200 to 3,000 ppm by mass.

Description

Lubricating oil composition

The present invention relates to a lubricating oil composition, and more particularly to a lubricating oil composition for an internal combustion engine, particularly a lubricating oil composition for a gasoline engine.

Lubricating oil compositions are widely used in the automotive field such as for internal combustion engines, automatic transmissions, and gear oils. In recent years, a reduction in viscosity has been demanded in order to improve fuel efficiency, but the oil film becomes thinner due to the reduction in viscosity, and friction cannot be reduced sufficiently. Therefore, molybdenum dithiocarbamate (MoDTC) that can reduce friction by generating molybdenum disulfide under boundary lubrication conditions has been conventionally used. In this case, it is usual to use a calcium-based detergent in combination (for example, JP 2013-199594 A (Patent Document 1)). However, with this combination, there is a limit to the reduction of friction, and the fuel consumption cannot be sufficiently improved.

It is also known to use a magnesium-based detergent as a detergent (for example, JP 2011-184666 A (Patent Document 2) and JP 2006-328265 A (Patent Document 3)). The use of magnesium-based detergents can reduce friction more than calcium-based detergents, but there is a problem that wear tends to occur.

JP 2013-199594 A JP 2011-184666 A JP 2006-328265 A

An object of the present invention is to provide a lubricating oil composition capable of reducing friction while ensuring antiwear properties even when the viscosity is lowered, and as a preferred embodiment, a lubricating oil composition used in an internal combustion engine, more preferably Is to provide a lubricating oil composition for use in a supercharged gasoline engine.

As a result of intensive studies, the present inventors have added a specific amount of a metal salicylate selected from calcium salicylate and magnesium salicylate to a lubricating base oil, and a specific amount of a molybdenum friction modifier. The present inventors have found that the above object is achieved.

That is, the present invention
A lubricating oil composition comprising a lubricating base oil, (A1) a metal-based salicylate, and (B) a molybdenum-based friction modifier,
The amount of component (B) is in the range of 500 to 1500 mass ppm as the concentration [B] of molybdenum in the lubricating oil composition by mass ppm,
The component (A1) is any of calcium salicylate, magnesium salicylate, or a combination thereof, and the amount of the calcium salicylate is 0 to 0 as a concentration [Ca] of calcium derived from the calcium salicylate in the lubricating oil composition. 1800 ppm by mass, the amount of magnesium salicylate is 0 to 1800 ppm by mass as the concentration [Mg] of magnesium derived from magnesium salicylate in the lubricating oil composition in terms of ppm by mass, and the above [Ca] and [[ A lubricating oil composition characterized in that the total Mg is in the range of 200 to 3000 ppm by mass.

In a preferred embodiment of the present invention, the lubricating oil composition further has at least one of the following characteristics (1) to (10).
(1) (A) Lubricating oil composition containing a metallic detergent, (A1) metallic salicylate with respect to the total mass of component (A), the metal derived from the metallic detergent in the lubricating oil composition A lubricating oil composition comprising 5 to 100% by mass of the ratio of [Ca] and [Mg] to the concentration [A] based on the total mass ppm.
(2) The lubricating oil composition may further contain (A) a metallic detergent other than the above-mentioned (A1) component as a metallic detergent, and (A) (A1) component relative to the total mass of the metallic detergent. Is in the range of 5 to 100% by mass.
(3) (A1) The metal salicylate is magnesium salicylate and calcium salicylate.
(4) (A1) The metal salicylate is at least one magnesium salicylate.
(5) The lubricating oil composition further comprises (A) a metal detergent (A2) other than the component (A1) as a metal detergent, and the component (A2) is at least one selected from magnesium, calcium and sodium. The total content of the (A) metal-based detergent is represented by the formula (1):
[A] / [B] ≦ 4.5 (1)
([A] is the concentration based on the total mass ppm of magnesium, calcium and sodium in the lubricating oil composition)
Meet.
(6) (A1) The content of the metal salicylate is represented by the following formula (2):
[A1] / [B] <4.5 (2)
([A1] is the concentration by the total mass ppm of magnesium and calcium derived from the component (A1) in the lubricating oil composition ([Ca] + [Mg]))
Meet.
(7) The CCS viscosity at −35 ° C. is 6.2 Pa · s or less.
(8) The high temperature high shear viscosity (HTHS viscosity) at 150 ° C. is 1.7 to 2.9 mPa · s.
(9) The kinematic viscosity at 100 ° C. is less than 9.3 mm ² / s.
(10) 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 of the above embodiments (1) to (10).

The lubricating oil composition of the present invention can reduce friction while ensuring wear resistance even when the viscosity is lowered. In particular, the lubricating oil composition for internal combustion engines, and further used for supercharged gasoline engines. It can be suitably used as an oil composition.

Lubricating oil base oil The lubricating oil 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.

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 dewaxing, and hydrogen removal. Refined by one or more treatments such as hydrorefining, wax isomerized mineral oil, GTL (Gas to Liquid) base oil, ATL (Asphalt to Liquid) base oil, vegetable oil base oil or a mixture thereof Mention may be made of base oils.

Synthetic oils include, for example, polybutene or hydrides thereof; poly-α-olefins such as 1-octene oligomers and 1-decene oligomers or hydrides thereof; 2-ethylhexyl laurate, 2-ethylhexyl palmitate, 2-stearate Monoesters such as ethylhexyl; diesters such as ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, di-2-ethylhexyl sebacate; neopentyl glycol di-2-ethylhexanoate, neopentyl Glycol di-n-octanoate, neopentyl glycol di-n-decanoate, trimethylolpropane tri-n-octanoate, trimethylolpropane tri-n-decanoate, pentaerythritol tet -Polyol esters such as n-pentanoate, pentaerythritol tetra-n-hexanoate, pentaerythritol tetra-2-ethylhexanoate; aromatic synthetic oils such as alkyl naphthalene, alkyl benzene, aromatic esters or mixtures thereof it can.

The kinematic viscosity (mm ² / s) at 100 ° C. of the lubricating base oil is not particularly limited, but is preferably 2 to 15 mm ^{2 /} s, more preferably 3 to 10 mm ² / s, and even 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.

The viscosity index (VI) 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.

(A) Metallic detergent (A1) Metallic salicylate The lubricating oil composition of the present invention comprises (A) a metallic detergent, (A1) calcium salicylate which is a metallic salicylate, magnesium salicylate, or a combination thereof. It is characterized by being included in the specific range amounts described below. The lubricating oil composition of the present invention may further contain (A) a metal detergent other than calcium salicylate and magnesium salicylate as a metal detergent, but (A) relative to the total mass of the metal detergent (A1). [Ca] and [Mg] ([Ca] is derived from calcium salicylate in the lubricating oil composition) with respect to the concentration [A] based on the total mass ppm of the metal derived from the metallic detergent in the lubricating oil composition. The concentration of calcium in ppm by mass, and [Mg] is the concentration of magnesium derived from magnesium salicylate in the lubricating oil composition) in the range of 5 to 100% by mass, preferably 10 to 100% by mass. It is preferably 15 to 100% by mass, particularly preferably 20 to 100% by mass, and most preferably 50 to 100% by mass. By containing one or more selected from calcium salicylate and magnesium salicylate as a metal detergent in a specific amount, high-temperature cleanliness and rust resistance required as a lubricating oil can be ensured. Also, friction can be reduced and thus torque can be reduced. This is particularly advantageous in terms of fuel consumption characteristics.

The amount of the component (A1) in the lubricating oil composition of the present invention is such that the amount of the calcium salicylate is 0 to 1800 mass ppm, preferably 0 to 1600 mass as the concentration [Ca] based on the mass ppm of calcium in the lubricating oil composition. The concentration of magnesium salicylate is 0 to 1800 ppm by mass, preferably 0 to 1600 ppm by mass, as the concentration [Mg] of magnesium in the lubricating oil composition, and the above [Ca] + [ Mg] is an amount that is in the range of 200 to 3000 ppm by mass, preferably 300 to 2500 ppm by mass, more preferably 400 to 2000 ppm by mass. If the amount of the component (A1) exceeds the above upper limit, wear may become excessive or sludge may come out. If the amount is less than the above lower limit, the friction reducing effect is low.

As described above, in the present invention, at least one selected from magnesium salicylate and calcium salicylate is essential as the metallic salicylate. Among these, only 1 type may be used or 2 or more types may be used together. Preferred is a combination of magnesium salicylate and calcium salicylate, or only magnesium salicylate, and more preferred is magnesium salicylate.

When the component (A1) is only magnesium salicylate, the content thereof is such that the concentration [Mg] of magnesium derived from magnesium salicylate in the lubricating oil composition is 200 to 1800 mass ppm, preferably 250 to 1500 mass ppm. More preferably, it is in the range of 300 to 1200 ppm by mass, and most preferably in the range of 400 to 1000 ppm. When the component (A1) is only calcium salicylate, the content thereof is such that the concentration [Ca] of calcium derived from calcium salicylate in the lubricating oil composition is 200 to 1800 ppm by mass, preferably 300 to 1600 ppm by mass. More preferably, the amount is in the range of 500 to 1400 mass ppm. When the component (A1) is a combination of magnesium salicylate and calcium salicylate, the total of [Ca] and [Mg] is 200 to 3000 mass ppm, preferably 300 to 2500 mass ppm, more preferably 400 to 2000 mass ppm. It is sufficient to satisfy the range. In particular, [Mg] ranges from 100 to 1600 mass ppm, preferably from 150 to 1400 mass ppm, more preferably from 200 to 1200 mass ppm, most preferably from 300 to 1000 ppm, and [Ca] from 100 to 1600 ppm. The mass may be in the range of ppm, preferably 300-1500 ppm by mass, more preferably 500-1400 ppm by mass.

The magnesium content in the magnesium salicylate and the calcium content in the calcium salicylate are each preferably 0.5 to 20% by mass, more preferably 1 to 16% by mass, and most preferably 2 to 14% by mass. . The blending amount of the component (A1) is adjusted so that the lubricating oil composition contains magnesium and calcium in the above-mentioned ranges.

(A1) The metal salicylate is particularly preferably an overbased metal salicylate, more preferably magnesium salicylate and calcium salicylate, and particularly preferably an overbased magnesium salicylate. Thereby, the acid neutralization property required for lubricating oil is securable. When overbased magnesium salicylate is used, neutral magnesium or calcium-based detergents may be mixed. When using an overbased calcium salicylate, a neutral calcium detergent may be used in combination.

(A1) The total base number of the metal salicylate is not limited, but is preferably 20 to 600 mgKOH / g, more preferably 50 to 500 mgKOH / g, and most preferably 100 to 450 mgKOH / g. Thereby, the acid neutralization property, high temperature cleanliness, and rust prevention property which are required for lubricating oil are securable. In addition, when mixing and using 2 or more types of metal-type salicylates, it is preferable that the base number obtained by mixing becomes said range.

The amount of the component (A1) in the lubricating oil composition is preferably an amount that satisfies the following formula (2).
[A1] / [B] <4.5 (2)
In the formula (2), [A1] is the concentration by the total mass ppm of magnesium and calcium derived from (A1) magnesium salicylate and calcium salicylate in the lubricating oil composition (that is, [Ca] + [Mg] described above) Indicates. [B] is as described above.
The value of [A1] / [B] is preferably less than 3.0, more preferably less than 2, still more preferably less than 1.8, and particularly preferably less than 1.5. If the value exceeds the upper limit, the torque reduction effect may be low. The lower limit of [A1] / [B] is preferably 0.1, more preferably 0.2, and still more preferably 0.3.

Preferred embodiments of the lubricating oil composition of the present invention are, as described above, (A1) an embodiment containing only magnesium salicylate as the metal-based salicylate, or an embodiment containing a combination of magnesium salicylate and calcium salicylate as the (A1) component. The lubricating oil composition of the present invention may further contain (A) a metallic detergent (A1) other than calcium salicylate and magnesium salicylate (A2) as a metallic detergent. In this case, as described above, the mass ratio of the component (A1) to the mass of the whole (A) metal detergent is based on the concentration [A] based on the total mass ppm of the metal derived from the metal detergent in the lubricating oil composition. The ratio of [Ca] and [Mg] is 5 to 100% by mass, preferably 10 to 100% by mass, more preferably 15 to 100% by mass, particularly preferably 20 to 100% by mass, and most preferably 50%. It should be ˜100% by mass. Specifically, (A) The mass% of magnesium salicylate relative to the total mass of the metal detergent is the ratio of [Mg] to the concentration [A] by the total mass ppm of metal derived from the metal detergent in the lubricating oil composition. The amount may be 5 to 100% by mass, preferably 10 to 80% by mass, more preferably 10 to 60% by mass, and particularly preferably 10 to 40% by mass. In a more preferred embodiment, (A) the metal detergent contains only magnesium salicylate, or contains only a combination of magnesium salicylate and calcium salicylate.

(A2) Metallic detergent other than the above metal-based salicylate The lubricating oil composition of the present invention is (A1) at least one selected from magnesium, calcium and sodium as a component of the metal-based detergent (A2) other than the metal-based salicylate. A conventionally known metal-based detergent containing can be used in combination. Examples of the component (A2) include metal sulfonates. The metal sulfonate may be one kind or a combination of two or more kinds. By containing a metal sulfonate, it is possible to further ensure high-temperature cleanliness and rust prevention necessary as a lubricating oil. The amount of the component (A2) depends on the amount of the component (A1), but the concentration (A2) of the metal derived from the component (A2) in the lubricating oil composition is preferably 0 to 5000 ppm by mass, more preferably Is 0 to 2000 ppm by mass, most preferably 0 to 1000 ppm by mass.

Examples of the metal sulfonate include magnesium sulfonate, calcium sulfonate, and sodium sulfonate.

In addition, a conventional metal detergent other than the above can be used within a range not impairing the effects of the present invention. For example, magnesium phenate, calcium phenate, and sodium detergent may be included. As the sodium-based detergent, sodium sulfonate, sodium phenate and sodium salicylate are preferable. These sodium-based detergents may be used alone or in combination of two or more. By including a sodium-based detergent, it is possible to ensure the high-temperature cleanability and rust prevention necessary as a lubricating oil. The sodium-based detergent can be used in combination with the above-described magnesium-based detergent and optional calcium-based detergent.

Preferably, the total amount of (A) the metallic detergent in the lubricating oil composition satisfies the following formula (1).
[A] / [B] ≦ 4.5 (1)
In the formula (1), [A] represents the concentration of magnesium, calcium and sodium in the lubricating oil composition by the total mass ppm, and [B] represents the concentration of molybdenum in the lubricating oil composition by ppm.
The value of [A] / [B] is preferably 3.0 or less, more preferably 2.8 or less, still more preferably 2.6 or less, and even more preferably 2.5 or less. If the above value exceeds the above upper limit value, wear may become excessive. The lower limit of [A] / [B] is preferably 0.2, more preferably 0.5, and even more preferably 1.

(B) Molybdenum-based friction modifier The molybdenum-based friction modifier is not particularly limited, and conventionally known ones can be used. For example, sulfur-containing organic molybdenum compounds such as molybdenum dithiophosphate (MoDTP) and molybdenum dithiocarbamate (MoDTC), complexes of molybdenum compounds with sulfur-containing organic compounds or other organic compounds, and molybdenum sulfides and sulfurized molybdenum acids. And a complex of a sulfur-containing molybdenum compound and an alkenyl succinimide. 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. Examples thereof include molybdenum sulfides such as acid salts, molybdenum disulfide, molybdenum trisulfide, molybdenum pentasulfide and polysulfide molybdenum, molybdenum sulfides, metal salts or amine salts of molybdenum sulfides, and molybdenum halides such as molybdenum chloride. Examples of the sulfur-containing organic compound include alkyl (thio) xanthate, thiadiazole, mercaptothiadiazole, thiocarbonate, tetrahydrocarbyl thiuram disulfide, bis (di (thio) hydrocarbyl dithiophosphonate) disulfide, and organic (poly) sulfide. And sulfurized esters. In particular, organic molybdenum compounds such as molybdenum dithiophosphate (MoDTP) and molybdenum dithiocarbamate (MoDTC) are preferable.

Molybdenum dithiocarbamate (MoDTC) is a compound represented by the following formula [I], and molybdenum dithiophosphate (MoDTP) is a compound represented by the following [II].

In the above general formulas [I] and [II], R ₁ to R ₈ may be the same or different from each other, and are monovalent hydrocarbon groups having 1 to 30 carbon atoms. The hydrocarbon group may be linear or branched. Examples of the monovalent hydrocarbon group include 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 an aryl having 6 to 30 carbon atoms. A group, an alkylaryl group or an arylalkyl group. In the arylalkyl 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, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, and 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 ₁ and X ₂ are oxygen atoms or sulfur atoms, and Y ₁ and Y ₂ are oxygen atoms or sulfur atoms.

(B) An organic molybdenum compound containing no sulfur can also be used. Examples of such compounds include molybdenum-amine complexes, molybdenum-succinimide complexes, molybdenum salts of organic acids, and molybdenum salts of alcohols.

Further, as the friction modifier (B) in the present invention, a trinuclear molybdenum compound described in US Pat. No. 5,906,968 can also be used.

The component (B) is added in such an amount that the concentration [B] of molybdenum in the lubricating oil composition as ppm is in the range of 500 to 1500 mass ppm, preferably 600 to 1200 mass ppm. When the amount of the component (B) exceeds the above upper limit, the cleanliness may be deteriorated, and when it is less than the above lower limit, the friction may not be sufficiently reduced or the cleanliness may be deteriorated. is there.

As described above for the component (A), the amount of the component (B) is preferably the following formula (1):
[A] / [B] ≦ 4.5 (1)
Meet. In the formula (1), [A] represents the concentration of magnesium, calcium and sodium in the lubricating oil composition by the total mass ppm, and [B] represents the concentration of molybdenum in the lubricating oil composition by ppm.
The value of [A] / [B] is preferably 3.0 or less, more preferably 2.8 or less, still more preferably 2.6 or less, and even more preferably 2.5 or less. The lower limit of [A] / [B] is preferably 0.2, more preferably 0.5, and still more preferably 1.0.

As described above for the component (A1), the amount of the component (B) is preferably the following formula (2):
[A1] / [B] <4.5 (2)
Meet. Here, [A1] indicates the concentration in ppm by mass of the metal derived from the component (A1) in the lubricating oil composition. The value of [A1] / [B] is preferably less than 3.0, more preferably less than 2.0, still more preferably less than 1.8, and particularly preferably less than 1.5. If the value exceeds the upper limit, the torque reduction effect may be low. The lower limit of [A1] / [B] is preferably 0.1, more preferably 0.2, and still more preferably 0.3.

The lubricating oil composition of the present invention comprises the above lubricating base oil, (A1) component and (B) component as essential components, but optionally includes conventionally known antiwear agents, ashless dispersants and viscosity index improvers. May be included.

As the antiwear agent, conventionally known antiwear agents can be used. Among these, a wear inhibitor having phosphorus is preferable, and zinc dithiophosphate (ZnDTP (also referred to as ZDDP)) represented by the following formula is particularly preferable.

In the above formula, R ¹ and R ² 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. The monovalent hydrocarbon group includes a primary (primary) or secondary (secondary) alkyl group having 1 to 26 carbon atoms; an alkenyl group having 2 to 26 carbon atoms; a cycloalkyl group having 6 to 26 carbon atoms; carbon An aryl group, an alkylaryl group or an arylalkyl group of formula 6 to 26; or a hydrocarbon group containing an ester bond, an ether bond, an alcohol group or a carboxyl group. R ¹ and R ² are preferably a primary or secondary alkyl group having 2 to 12 carbon atoms, a cycloalkyl group having 8 to 18 carbon atoms, and an alkylaryl group having 8 to 18 carbon atoms, They may be the same or different. In particular, zinc dialkyldithiophosphate is preferable, and the primary alkyl group preferably has 3 to 12 carbon atoms, more preferably 4 to 10 carbon atoms. The secondary alkyl group preferably has 3 to 12 carbon atoms, more preferably 3 to 10 carbon atoms. The said zinc dithiophosphate may be used individually by 1 type, and may mix and use 2 or more types. Further, zinc dithiocarbamate (ZnDTC) may be used in combination.

Also, at least one compound selected from phosphates represented by the following formulas (3) and (4), phosphite-based phosphorus compounds, and metal salts and amine salts thereof can also be used.

In the general formula (3), R ³ is a monovalent hydrocarbon group having 1 to 30 carbon atoms, and R ⁴ and R ⁵ are each independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 30 carbon atoms. And m is 0 or 1.

In the general formula (4), R ⁶ is a monovalent hydrocarbon group having 1 to 30 carbon atoms, and R ⁷ and R ⁸ are independently a hydrogen atom or a monovalent hydrocarbon group having 1 to 30 carbon atoms. , N is 0 or 1.

In the above general formulas (3) and (4), examples of the monovalent hydrocarbon group having 1 to 30 carbon atoms represented by R ³ to R ⁸ include an alkyl group, a cycloalkyl group, an alkenyl group, and an alkyl-substituted cyclohexane. Mention may be made of alkyl groups, aryl groups, alkyl-substituted aryl groups, and arylalkyl groups. In particular, it is preferably an alkyl group having 1 to 30 carbon atoms or an aryl group having 6 to 24 carbon atoms, more preferably an alkyl group having 3 to 18 carbon atoms, and most preferably an alkyl group having 4 to 15 carbon atoms. It is.

Examples of the phosphorus compound represented by the general formula (3) include phosphorous acid monoester and (hydrocarbyl) phosphonous acid having one hydrocarbon group having 1 to 30 carbon atoms; A phosphite diester having two hydrocarbon groups, a monothiophosphite diester, and a (hydrocarbyl) phosphonous monoester; a phosphite triester having three hydrocarbon groups having 1 to 30 carbon atoms, and (Hydrocarbyl) phosphonous acid diesters; and mixtures thereof.

The metal salt or amine salt of the phosphorus compound represented by the general formula (3) or (4) is a metal oxide, a metal hydroxide, a phosphorus compound represented by the general formula (3) or (4), Remains after acting with a metal base such as metal carbonate, metal chloride, ammonia, nitrogen compound such as amine compound having only 1-30 hydrocarbon group or hydroxyl group-containing hydrocarbon group in the molecule. It can be obtained by neutralizing part or all of the acidic hydrogen. Examples of the metal in the metal base include alkali metals such as lithium, sodium, potassium and cesium, alkaline earth metals such as calcium, magnesium and barium, and heavy metals such as zinc, copper, iron, lead, nickel, silver and manganese. (However, excluding molybdenum). Among these, alkaline earth metals such as calcium and magnesium and zinc are preferable, and zinc is particularly preferable.

The antiwear agent is usually blended in the lubricating oil composition at 0.1 to 5.0% by mass, preferably 0.2 to 3.0% by mass.

Examples of the ashless dispersant include nitrogen-containing compounds having at least one linear or branched alkyl group or alkenyl group having 40 to 500 carbon atoms, preferably 60 to 350, or derivatives thereof, and Mannich dispersants. Or a mono- or bissuccinimide (eg, alkenyl succinimide), an alkyl group having 40 to 500 carbon atoms or a benzylamine having at least one alkenyl group in the molecule, or an alkyl group or alkenyl group having 40 to 400 carbon atoms And polyamines having at least one in the molecule, or modified products of these compounds with boron compounds, carboxylic acids, phosphoric acids, and the like. One type or two or more types arbitrarily selected from these can be blended. In particular, alkenyl succinimide is preferably contained.

The method for producing the succinimide is not particularly limited. For example, an alkyl succinic acid or alkenyl succinic acid obtained by reacting a compound having an alkyl group or alkenyl group having 40 to 500 carbon atoms with maleic anhydride at 100 to 200 ° C. It is obtained by reacting an acid with a polyamine. Here, examples of the polyamine include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine. Examples of the derivative of the nitrogen-containing compound exemplified as the above ashless dispersant include, for example, monocarboxylic acids such as fatty acids having 1 to 30 carbon atoms, oxalic acid, phthalic acid, trimellitic acid, pyromellitic to the aforementioned nitrogen-containing compounds. The remaining amino group and / or the reaction of a polycarboxylic acid having 2 to 30 carbon atoms such as an acid, or an anhydride thereof, or an ester compound, an alkylene oxide having 2 to 6 carbon atoms, or a hydroxy (poly) oxyalkylene carbonate. Modified compounds by so-called oxygen-containing organic compounds, in which some or all of the imino groups are neutralized or amidated; one of the remaining amino groups and / or imino groups by reacting boric acid with the nitrogen-containing compounds described above A so-called boron-modified compound obtained by neutralizing a part or the whole or amidated; A so-called phosphoric acid-modified compound obtained by neutralizing or amidating part or all of the amino group and / or imino group; a sulfur-modified compound obtained by allowing a sulfur compound to act on the nitrogen-containing compound described above; and the nitrogen-containing compound described above And modified compounds in which two or more kinds of modifications selected from modification with oxygen-containing organic compounds, boron modification, phosphoric acid modification, and sulfur modification are combined. Among these derivatives, a boric acid-modified compound of alkenyl succinimide, particularly a boric acid-modified compound of bis-type alkenyl succinimide, can further improve heat resistance when used in combination with the above base oil.

The amount of the ashless dispersant is 20% by mass or less, preferably 15% by mass or less, more preferably 5% by mass or less, based on the total amount of the composition. Further, as an ashless dispersant, a boron-containing ashless dispersant may be used by mixing with an ashless dispersant not containing boron. Further, when the boron-containing ashless dispersant is used, the content ratio is not particularly limited, but the boron amount contained in the composition is preferably 0.001 to 0.2% by mass based on the total amount of the composition, More preferably, it is 0.003 to 0.1% by mass, and most preferably 0.005 to 0.05% by mass.

The number average molecular weight (Mn) of the ashless dispersant is preferably 2000 or more, more preferably 2500 or more, still more preferably 3000 or more, most preferably 5000 or more, and preferably 15000 or less. . If the number average molecular weight of the ashless dispersant is less than the above lower limit, dispersibility may not be sufficient. On the other hand, when the number average molecular weight of the ashless dispersant exceeds the above upper limit, the viscosity is too high, the fluidity becomes insufficient, and the deposit increases.

Examples of the viscosity index improver include polymethacrylate, dispersed polymethacrylate, olefin copolymer (polyisobutylene, ethylene-propylene copolymer), dispersed olefin copolymer, polyalkylstyrene, styrene-butadiene hydrogenated copolymer. Styrene-maleic anhydride copolymer, star-like isoprene, and the like. Furthermore, a comb polymer containing at least a repeating unit based on a polyolefin macromer 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 also be used.

Viscosity index improver usually consists of the above polymer and diluent oil. The content of the viscosity index improver is preferably 0.01 to 20% by mass, more preferably 0.02 to 10% by mass, and most preferably 0.05 to 5% by mass as a polymer amount based on the total amount of the composition. %. 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 upper limit, the viscosity temperature characteristics and the low temperature viscosity characteristics may be deteriorated, and the product cost will be significantly increased.

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, friction modifiers other than the above component (B), corrosion inhibitors, rust inhibitors, flow Examples thereof include additives such as point depressants, demulsifiers, metal deactivators and antifoaming agents.

Examples of the antioxidant include ashless antioxidants such as phenols and amines, and metal antioxidants such as copper and molybdenum. For example, phenolic ashless antioxidants include 4,4'-methylenebis (2,6-di-tert-butylphenol), 4,4'-bis (2,6-di-tert-butylphenol), isooctyl- 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate and the like, and amine-based ashless antioxidants include phenyl-α-naphthylamine, alkylphenyl-α-naphthylamine, dialkyldiphenylamine and the like. It is done. The antioxidant is usually blended at 0.1 to 5% by mass in the lubricating oil composition.

Examples of the friction modifier other than the component (B) include esters, amines, amides, and sulfurized esters. The friction modifier is usually blended at 0.01 to 3% by mass in the lubricating oil composition.

Examples of the corrosion inhibitor include benzotriazole, tolyltriazole, thiadiazole, and imidazole compounds. Examples of the rust inhibitor include petroleum sulfonate, alkylbenzene sulfonate, dinonylnaphthalene sulfonate, alkenyl succinic acid ester, and polyhydric alcohol ester. The rust inhibitor and the corrosion inhibitor are usually blended in the lubricating oil composition at 0.01 to 5% by mass, respectively.

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 0.01 to 3% by weight.

Examples of the demulsifier include polyalkylene glycol nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl naphthyl ether, and the like. The demulsifier is usually blended in the lubricating oil composition at 0.01 to 5% by mass.

Examples of the metal deactivator include imidazoline, pyrimidine derivatives, alkylthiadiazoles, mercaptobenzothiazoles, benzotriazoles or derivatives thereof, 1,3,4-thiadiazole polysulfide, 1,3,4-thiadiazolyl-2,5- Examples thereof include bisdialkyldithiocarbamate, 2- (alkyldithio) benzimidazole, β- (o-carboxybenzylthio) propiononitrile. The metal deactivator is usually blended in the lubricating oil composition at 0.01 to 3% by mass.

Examples of the antifoaming agent include silicone oil having a kinematic viscosity at 25 ° C. of 1,000 to 100,000 mm ² / s, alkenyl succinic acid derivative, ester of polyhydroxy aliphatic alcohol and long chain fatty acid, methyl salicylate and o -Hydroxybenzyl alcohol and the like. The antifoaming agent is usually blended in the lubricating oil composition at 0.001 to 1% by mass.

As other additives, alkali borate additives can be added. An alkali borate-based additive contains an alkali metal borate hydrate and can be represented by the following general formula.
M ₂ O · xB ₂ O ₃ · yH ₂ O
In the above formula, M is an alkali metal, x is 2.5 to 4.5, and y is 1.0 to 4.8.
Specific examples include lithium borate hydrate, sodium borate hydrate, potassium borate hydrate, rubidium borate hydrate, cesium borate hydrate, and the like. Hydrates and sodium borate hydrate are preferable, and potassium borate hydrate is particularly preferable. The average particle size of the alkali metal borate hydrate particles is generally 1 micron (μ) or less. In the alkali metal borate hydrate used in the present invention, the ratio of boron to alkali metal is preferably in the range of about 2.5: 1 to 4.5: 1. The addition amount of the alkali borate-based additive is 0.002 to 0.05 mass% as the boron amount based on the total amount of the lubricating oil composition.

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

In the lubricating oil composition of the present invention, the amount of molybdenum contained in the lubricating oil composition and the CCS viscosity at −35 ° C. preferably satisfy the following formula (5).
[CCS viscosity] / [B] ≦ 0.01 (5)
([CCS viscosity] indicates the value (Pa · s) of the CCS viscosity at −35 ° C. of the lubricating oil composition, and [B] indicates the concentration in terms of ppm by mass of molybdenum in the lubricating oil composition.)
The value of [CCS viscosity] / [B] is more preferably 0.008 or less, and still more preferably 0.005 or less. If the above value exceeds 0.01, the torque reduction rate may be reduced or the cleanliness may be deteriorated. Although the lower limit value of [CCS viscosity] / [B] is not limited, it is preferably 0.002, more preferably 0.003.

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 preferably 1.7 to 2.9 mPa.s. s, more preferably 2.0 to 2.6 mPa.s. s.

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.

The lubricating oil composition of the present invention has an effect of having a sufficient frictional characteristic and wear characteristic even when having a low viscosity, and obtaining a high torque reduction rate. It can be suitably used for use.

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.

The materials used in Examples and Comparative Examples are as follows.
Lubricating oil base oil Lubricating oil base oil: Fischer-Tropsch derived base oil, kinematic viscosity at 100 ° C. = 4.1 mm ² / s, VI = 127

Metal detergent (A)
(A1) Metallic salicylate (A1-1) Magnesium salicylate (total base number 340 mgKOH / g, magnesium content 7.5% by mass)
(A1-2) Calcium salicylate 1 (total base number 350 mgKOH / g, calcium content 12.0% by mass)
(A1-3) Calcium salicylate 2 (total base number 220 mgKOH / g, calcium content 8.0 mass%)

(A2) Metal sulfonate (A2-1) Magnesium sulfonate (total base number 400 mgKOH / g, magnesium content 9.0% by mass)
(A2-2) Calcium sulfonate (total base number 300 mgKOH / g, calcium content 11.6% by mass)

Molybdenum friction modifier (B)
Molybdenum-based friction modifier: MoDTC (a compound in which X ₁ and X ₂ are O and Y ₁ and Y ₂ are S in the above formula [1]. Molybdenum content 10% by mass)

Antiwear agent Antiwear agent 1: pri-ZnDTP (primary alkyl group) Antiwear agent 2: sec-ZnDTP (secondary alkyl group)

Other additives Antioxidant: Phenolic antioxidant Ashless dispersant: Succinimide Viscosity index improver: Polymethacrylate Antifoaming agent: Dimethyl silicone

Examples 1 to 12 and Comparative Examples 1 to 8
Lubricating oil compositions were prepared by mixing the components in the amounts shown in Tables 1 and 3. The amounts of magnesium-based detergent, calcium-based detergent and molybdenum-based friction modifier listed in Tables 1 and 3 are the concentrations (in order of ppm) of magnesium, calcium and molybdenum content (mass ppm) with respect to the total amount of the lubricating oil composition. , [Mg], [Ca], and [B]). The amount of the antiwear agent and other additives is part by mass with respect to the total amount (100 parts by mass) of the lubricating oil composition. In addition, the amount of magnesium-based detergent and calcium-based detergent was such that the total molar amount of magnesium and calcium contained in these detergents was as identical as possible in all examples and comparative examples. The following test was done about the obtained composition. The results are shown in Tables 2 and 4.

In Tables 1 and 3 below, [A] is the concentration based on the total mass ppm of total magnesium and total calcium contained in the lubricating oil composition (that is, including Mg and Ca derived from magnesium sulfonate and calcium sulfonate). , [A1] is the concentration (namely, [Ca] + [Mg]) of the total mass ppm of magnesium and calcium derived from the (A1) metal salicylate in the lubricating oil composition. [A1] / [A] is the concentration [A1] of the total mass ppm of magnesium and calcium derived from the metal-based salicylate with respect to the concentration [A] of the total magnesium and total calcium contained in the lubricating oil composition. ] Mass%.

(1) High temperature high shear viscosity at 150 ° C. (HTHS150)
Measured according to ASTM D4683.

(2) CCS viscosity at -35 ° C (CCS viscosity)
Measured according to ASTM D5293.

(3) Kinematic viscosity at 100 ° C (KV100)
Measurement was performed at 100 ° C. in accordance with ASTM D445.

(4) Torque reduction rate Torque was measured in a motoring test using a gasoline engine using the lubricating oil compositions obtained in the examples and comparative examples as test compositions. The engine was a Toyota 2ZR-FE1.8L inline 4-cylinder engine, a torque meter was installed between the motor and the engine, and the torque at an oil temperature of 80 ° C. and an engine speed of 700 RPM was measured. Torque was measured in the same manner using a commercially available GF-50O-20 oil as a standard oil. The torque (T) of the test composition was compared with the torque (T ₀ ) of the standard oil, and the reduction rate ({(T ₀ −T) / T ₀ } × 100) (%) from the torque of the standard oil was calculated. It shows that fuel consumption is so favorable that a reduction rate is large. A reduction rate of 5.5% or more was accepted.

(5) Shell wear scar diameter Measured according to the shell four-ball test (ASTM D4172) except that the rotation speed was 1800 rpm, the load was 40 kgf, the test temperature was 90 ° C., and the test time was 30 minutes. Those having a wear scar diameter of 0.7 mm or less were regarded as acceptable.

(6) Hot tube test (evaluation of high temperature cleanliness)
The lubricating oil composition was continuously supplied at a rate of 0.3 ml / hour, air at 10 ml / second, and the temperature of the glass tube at 270 ° C. for 16 hours in a glass tube having an inner diameter of 2 mm. The lacquer adhering in the glass tube was compared with the color sample, and the score was given as 10 points for transparent and 0 points for black. The higher the score, the better the high temperature cleanliness. A score of 5.0 or higher was accepted.

As shown in Table 4, the compositions of Comparative Examples 1 to 3 having a high calcium salicylate (A1) content have a low torque reduction rate, and the composition of Comparative Example 6 having a large amount of magnesium salicylate (A) Is big. Further, the compositions of Comparative Examples 4 and 5 in which the amount of the molybdenum friction modifier (B) is less than the lower limit of the present invention has a low torque reduction rate and is inferior in high temperature cleanliness. Furthermore, the compositions of Comparative Examples 7 and 8 that do not contain a metal salicylate have a low torque reduction rate and inferior high-temperature cleanliness.
On the other hand, as shown in Table 2, the lubricating oil composition of the present invention has low wear and high torque reduction rate and high temperature cleanliness despite the low kinematic viscosity at 100 ° C.

Claims

A lubricating oil composition comprising a lubricating base oil, (A1) a metal-based salicylate, and (B) a molybdenum-based friction modifier,
The amount of component (B) is in the range of 500 to 1500 mass ppm as the concentration [B] of molybdenum in the lubricating oil composition by mass ppm,
The component (A1) is calcium salicylate, magnesium salicylate, or a combination thereof, and the amount of the calcium salicylate is 0 to 0 as a concentration [Ca] of calcium derived from the calcium salicylate in the lubricating oil composition. 1800 ppm by mass, the amount of magnesium salicylate is 0 to 1800 ppm by mass as the concentration [Mg] of magnesium derived from magnesium salicylate in the lubricating oil composition in terms of ppm by mass, and the above [Ca] and [[ A lubricating oil composition characterized in that the total Mg is in the range of 200 to 3000 ppm by mass.
The lubricating oil composition may further contain a metal detergent other than the component (A1) as the metal detergent (A), and the mass of the component (A1) relative to the mass of the whole metal detergent (A). The ratio of [Ca] and [Mg] to the concentration [A] in terms of the total mass ppm of the metal derived from the metal-based detergent in the lubricating oil composition is in the range of 5 to 100% by mass. The lubricating oil composition described.
(A1) The lubricating oil composition according to claim 1 or 2, wherein the metal salicylate is a combination of magnesium salicylate and calcium salicylate.
(A1) The lubricating oil composition according to claim 1 or 2, wherein the metal salicylate is at least one magnesium salicylate.
The lubricating oil composition further comprises (A) a metal detergent (A2) other than the component (A1) as a metal detergent, and the component (A2) contains at least one selected from magnesium, calcium and sodium. ,
(A) The amount of the metallic detergent is the following formula (1):
[A] / [B] ≦ 4.5 (1)
([A] is the concentration based on the total mass ppm of magnesium, calcium and sodium in the lubricating oil composition)
The lubricating oil composition according to any one of claims 1 to 4, which satisfies:
(A1) The amount of metal salicylate is represented by the following formula (2):
[A1] / [B] <4.5 (2)
([A1] is the concentration by the total mass ppm of magnesium and calcium derived from the component (A1) in the lubricating oil composition ([Ca] + [Mg]))
The lubricating oil composition according to any one of claims 1 to 5, which satisfies the following conditions.
The lubricating oil composition according to any one of claims 1 to 6, wherein the CCS viscosity at -35 ° C is 6.2 Pa · s or less.
The lubricating oil composition according to any one of claims 1 to 7, wherein a high-temperature high-shear viscosity (HTHS viscosity) at 150 ° C is 1.7 to 2.9 mPa · s.
The lubricating oil composition according to any one of claims 1 to 8, wherein the kinematic viscosity at 100 ° C is less than 9.3 mm 2 / s.
The lubricating oil composition according to any one of claims 1 to 9, which is used for an internal combustion engine.