JP6864461B2 - Lubricating oil composition - Google Patents

Description

The present invention relates to a lubricating oil composition, particularly a lubricating oil composition preferably used for an automobile transmission. More specifically, the present invention relates to a lubricating oil composition for a continuously variable transmission.

Lubricating oil compositions are widely used in the automobile field such as for internal combustion engines, automatic transmissions, and gear oils. In recent years, in order to achieve fuel efficiency, it has been required to reduce the viscosity of the lubricating oil composition. Further, a continuously variable transmission (CTV) has been widely used in place of a stepped automatic transmission, and a metal belt type CVT that uses a metal belt and a pulley for power transmission has become common.

One method for improving the fuel efficiency of continuously variable transmission vehicles is to expand the operating conditions of the lockup clutch, and it is required to extend the shudder prevention life of the lockup clutch. However, if the amount of the friction modifier is increased in order to extend the shudder prevention life, there arises a problem that the friction coefficient between metals between the metal belt and the pulley is lowered, the belt grip performance is lowered, and the torque transmission ability is lowered. As described above, the shudder prevention performance and the friction coefficient between metals are in a trade-off relationship, and it is required to achieve both sufficient torque characteristics and shudder prevention performance at a high level. When the viscosity of the lubricating oil composition for a transmission is reduced, there is also a problem that a sufficient coefficient of friction between metals cannot be obtained and a sufficiently large torque cannot be secured.

For example, Patent Documents 1 to 5 describe conventional lubricating oil compositions for continuously variable transmissions. Patent Document 1 describes a lubricating oil composition in which a specific boron-free succinimide compound and a phosphorus-based compound are blended and does not contain zinc dialkyldithiophosphate, and between a metal belt or chain and a pulley. It states that the coefficient of friction can be significantly improved, a high coefficient of friction can be maintained for a long period of time, and the clutch plate is not clogged. Patent Document 2 describes a lubricant composition containing a sulfonate-based cleaning agent, a salicylate-based cleaning agent, and a boron-containing succinimide-based additive in a specific amount and a specific amount ratio, and maintains sufficient torque transmission capacity and shifting characteristics. However, it states that it has excellent shudder prevention performance. Patent Document 3 describes a lubricating oil composition containing a specific amount of a boronized alkyl succinimide and / or a boronized alkenyl succinimide having a specific weight average molecular weight, and a metal-based cleaning agent having a linear alkyl group. However, it is stated that it has a high coefficient of friction between metals and is excellent in shifting characteristics and shudder prevention performance. Patent Document 4 describes a lubricating oil composition containing a specific sulfolane derivative, one or more selected from calcium sulfonate and calcium phenate, and a specific amount of a specific viscosity index improver, and has a high metal friction coefficient. , It is stated that both fuel saving and component durability due to low viscosity are achieved. Patent Document 5 provides a high coefficient of friction between metals and an anti-shudder property by blending at least four types of additives such as calcium salicylate, a phosphorus-based wear inhibitor, a friction modifier, and a dispersed viscosity index improver as essential components. It states that they are compatible.

Japanese Unexamined Patent Publication No. 2006-056934 JP-A-2007-126541 Japanese Unexamined Patent Publication No. 2009-215395 Japanese Unexamined Patent Publication No. 2010-180278 Japanese Unexamined Patent Publication No. 2000-355695

In view of the above circumstances, a first object of the present invention is to provide a lubricating oil composition having an extended shudder prevention life without lowering the coefficient of friction between metals even when the viscosity is lowered.

As a result of diligent studies, the present inventors have reduced the viscosity by combining two types of succinimide compounds having a specific mass average molecular weight as an ashless dispersant and further using a specific friction modifier in combination. It has been found that the shade prevention life can be extended without lowering the friction coefficient between metals even in the case, and the present invention has been achieved.

That is, the present invention
(A) Lubricating oil base oil,
(C) (C-1) Succinimide compound or borated succinimide compound having a mass average molecular weight of 4,000 to 7,000,
(C-2) Succinimide compound or borated succinimide compound having a mass average molecular weight of more than 7,000 to 10,000,
(D) (D-1) A lubricating oil composition comprising an amide-based friction modifier.

Further, in order to improve fuel efficiency, it is required to reduce the viscosity at low temperature (for example, 40 ° C.), which affects fuel efficiency, while maintaining the viscosity at high temperature (for example, 100 ° C.) as much as possible, that is, a high viscosity index. The conventional stepless transmission lubricating oil composition has a problem that the polymer chains of the base oil and the viscosity index improver are cut by mechanical shearing, which causes a decrease in high-temperature viscosity with running.

By further specifying the composition of the lubricating oil base oil (A) and the viscosity index improver in the lubricating oil composition, the present inventors have the effect of extending the shudder prevention life without lowering the friction coefficient between metals. It was found that the shear stability can be improved.
That is, the lubricating oil composition of the present invention is preferably
A poly-α-olefin or α-olefin copolymer having a ^{kinematic viscosity of 6 to 80 mm 2} / s at 100 ° C. as a part or all of the component (A) was added to the total mass of the lubricating oil composition by 5 parts. It contains ~ 30% by mass and (B) a polymethacrylate having a mass average molecular weight of 15,000 to 40,000.

(R1、R2、R3、R4はそれぞれ独立して水素原子、または1個〜３０個の炭素原子を含有する炭化水素を示し、そのうち少なくとも１個は炭化水素基である。)
（９）潤滑油組成物が、さらに、(Ｅ）金属清浄剤を含有する。
（１０）潤滑油組成物が、さらに、（Ｆ）エーテルスルホラン化合物を含有する。
（１１）潤滑油組成物が、無段変速機用である。 Further, a preferred embodiment of the lubricating oil composition of the present invention has at least one of the following characteristics (1) to (11).
(1) (D-2) Further contains a friction modifier composed of a reaction product of boric acid or boron oxide and an epoxide.
(2) The (C-1) component and a part or all of the (C-2) component are boronized succinimides.
(3) The (C-1) component and / or the (C-2) component each add boron to 0.1 to 3 with respect to the mass of the (C-1) component or the (C-2) component. It is contained in an amount of% by mass.
(4) The mass ratio of the component (C-1) to the component (C-2) is (C-2) / (C-1) = 1-10.
(5) The lubricating oil composition has a kinematic viscosity of 3 to 10 mm ² / s at 100 ° C.
(6) The lubricating oil composition has a viscosity index of 150 or more.
(7) At least one of the amide compounds (D-1) derived from a fatty acid having an alkyl group or an alkenyl group having 6 to 30 carbon atoms is selected.
(8) At least one of (D-2) is selected from a reaction product of an epoxide represented by the following general formula and boric acid or boron oxide, or a ring-opening product thereof.

(R1, R2, R3, and R4 each independently represent a hydrogen atom or a hydrocarbon containing 1 to 30 carbon atoms, of which at least one is a hydrocarbon group.)
(9) The lubricating oil composition further contains (E) a metal cleaning agent.
(10) The lubricating oil composition further contains (F) an ether sulfolane compound.
(11) The lubricating oil composition is for a continuously variable transmission.

In particular, the lubricating oil composition lubricates a poly-α-olefin or α-olefin copolymer having a ^{kinematic viscosity of 6 to 80 mm 2} / s at 100 ° C. as a part or all of the component (A). It is preferably contained in an amount of 5 to 30% by mass based on the total mass of the oil composition, and preferably contains the (E) ether sulfolane compound. Synthetic base oils have a lower affinity for oil seal rubbers called packings and gaskets than mineral oils, and higher molecular weight (higher viscosity) base oils have a lower affinity. If the affinity is low, the swelling of the seal rubber is reduced, and conversely, it is easy to shrink. As a result, there is a problem that the sealing property is lowered and oil leakage occurs. By adopting the lubricating oil composition of the present invention, the swelling property of the seal rubber can be further ensured.
Further, the lubricating oil composition is characterized by being excellent in initial shader properties by containing (D-2) a friction modifier composed of a reaction product of boric acid or boron oxide and an epoxide.

The lubricating oil composition of the present invention can extend the shudder prevention life without lowering the coefficient of friction between metals. This effect can be achieved even if the kinematic viscosity of the lubricating oil composition at 100 ° C. is reduced to about 5.0. Further, according to the present invention, it is possible to provide a lubricating oil composition having further improved shear stability in addition to the effect. Furthermore, the swelling property of the seal rubber can be ensured. Furthermore, among the shadder characteristics, the initial characteristics can be improved. The lubricating oil composition of the present invention can be particularly preferably used as a lubricating oil composition for continuously variable transmissions.

Hereinafter, each component will be described.

(A) Lubricating oil base oil As the lubricating oil base oil in the present invention, conventionally known lubricating oil base oils can be used, and there are mineral oils, synthetic oils, and mixed oils thereof. In particular, a poly α-olefin or α-olefin copolymer having a ^{kinematic viscosity of 6 to 80 mm 2} / s at 100 ° C. as a part or all of the lubricating oil base oil is added to the mass of the entire lubricating oil composition. The content is preferably 5 to 30% by mass, more preferably the lower limit is 6% by mass, more preferably 8% by mass, and the upper limit is 25% by mass, more preferably 20% by mass. If the content of the base oil is less than the lower limit, a sufficient viscosity index, that is, fuel efficiency and protection performance to mechanical elements cannot be obtained at the same time, and if the content exceeds the upper limit, the shear stability is lowered and the rubber is compatible. (Rubber shrinkage) may occur.

The poly-α-olefin and α-olefin copolymer ^{preferably have a kinematic viscosity of 6 to 80 mm 2} / s at 100 ° C., preferably 8 to 80 mm ² / s, and more preferably 8 to 60 mm ² / s. It is s, more preferably 9 to 40 mm ² / s. If the kinematic viscosity at 100 ° C is less than the lower limit, the viscosity index, that is, fuel efficiency and protection performance for mechanical elements cannot be achieved at the same time, and if the kinematic viscosity at 100 ° C exceeds the upper limit, shear stability is not obtained. It is not preferable because it deteriorates the compatibility of rubber and rubber (shrinkage of rubber).

The poly-α-olefin or α-olefin copolymer may be a (co) polymer or (co) oligomer of α-olefin and has the above-mentioned kinematic viscosity, and conventionally known lubricating oil base oils are used. Can be used. The α-olefin is selected from, for example, a linear or branched olefin hydrocarbon having 2 to 14 carbon atoms, preferably 4 to 12 carbon atoms. For example, 1-octene oligomer, 1-decene oligomer, ethylene-propylene oligomer, isobutene oligomer and hydrides thereof can be mentioned. Further, the poly-α-olefin or α-olefin copolymer may be produced by using a metallocene catalyst. The mass average molecular weight of the (co) polymer or (co) oligomer may be such that the kinematic viscosity at 100 ° C. satisfies the above range. For example, it has a mass average molecular weight of 1,000 to 10,000, preferably 1,100 to 7,000. As the poly-α-olefin or α-olefin copolymer, one type may be used alone, or two or more types may be used in combination.

The lubricating oil composition of the present invention may contain another lubricating oil base oil in combination with the above poly α-olefin or α-olefin copolymer. These lubricating oil base oils are not particularly limited, and conventionally known mineral oil-based base oils and synthetic base oils other than the above-mentioned poly α-olefins and α-olefin copolymers can be used.

As the mineral oil-based base oil, the lubricating oil distillate obtained by atmospheric distillation and vacuum distillation of crude oil is subjected to solvent desorption, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrorefining, and sulfuric acid. Paraffin-based and naphthen-based lubricating oil base oils that have been refined by appropriately combining refining treatments such as washing and white clay treatment, and lubricating oil base oils obtained by isomerizing and removing wax obtained by solvent dewaxing. Can be mentioned. The kinematic viscosity of the mineral oil-based base oil is not particularly limited, but in order to obtain a lubricating oil composition having a low viscosity, it is preferably ^{1 to 5 mm 2 / s.}

As the synthetic base oil, isoparaffin, alkylbenzene, alkylnaphthalene, monoester, diester, polyol ester, polyoxyalkylene glycol, dialkyldiphenyl ether, polyphenyl ether, GTL base oil and the like can be used. The kinematic viscosity of the synthetic base oil is not particularly limited. It is also possible to use a poly-α-olefin or α-olefin copolymer having a kinematic viscosity at 100 ° C. of ^{less than 6 mm 2} / s or more than 80 mm ^{2 / s.} In order to obtain a lubricating oil composition having a low viscosity, the kinematic viscosity of the synthetic base oil is preferably 1 to 6 ^{mm 2 / s.}

As the base oil that can be used in combination, one type may be used alone, or two or more types may be used. When using two or more types, use two or more types of mineral oil-based base oil, use two or more types of synthetic base oil, and use one or more types of mineral oil-based base oil and one or more types of synthetic base oil. Is possible. Among them, the single use of mineral oil-based base oil, the use of two or more kinds of mineral oil-based ^{base oil, the single use of synthetic base oil having a kinematic viscosity of 1 to 6 mm or less than 2} / s at 100 ° C., and the kinematic viscosity at 100 ° C. It is preferable to use two or more kinds of synthetic base oils having a ^{thickness of 1 to} 6 mm and less than 2 / s.

Further, in order to obtain a lubricating oil composition having a low viscosity, the lubricating oil base oil as a whole has a kinematic viscosity at 100 ° C. of ^{2 to} 7 mm 2 / s, preferably 2.3 to ⁶ mm 2 / s, particularly 2.5 to 5.6. It preferably has mm ^{2 / s.}

(B) Viscosity Index Improver The lubricating oil composition of the present invention can contain a conventionally known viscosity index improver. Preferably, the viscosity index improver contains polymethacrylate having a mass average molecular weight of 15,000 to 40,000. The lower limit of the mass average molecular weight is preferably 17,000, more preferably 18,000. The upper limit of the mass average molecular weight is preferably 38,000, more preferably 36,000. If the mass average molecular weight is less than the lower limit, the effect of improving the viscosity index is insufficient, and if the mass average molecular weight is more than the upper limit, the effect of improving the viscosity index can be obtained, but the shear stability. Is not preferable because it worsens. The content of the polymethacrylate is not limited, but is preferably 0.1 to 20% by mass, more preferably 1 to 15% by mass, still more preferably 2 to 10% by mass in the lubricating oil composition.

The above polymethacrylate may be used alone or in combination of two or more.

The lubricating oil composition of the present invention may contain another viscosity index improver in addition to the above polymethacrylate. Other viscosity index improvers include polymethacrylates having a mass average molecular weight of less than 15,000, polymethacrylates having a mass average molecular weight of more than 40,000, polyisobutylene and its hydrogenated products, and styrene-diene hydrogenated copolymers. Examples include coalescing, styrene-maleic anhydride copolymers and polyalkylstyrene. When another viscosity index improver is contained, the blending amount thereof is preferably 0.1 to 15% by mass in the lubricating oil composition.

(C) Succinimide Compound The lubricating oil composition of the present invention is characterized by containing two types of specific succinimide compounds as an ashless dispersant. That is, in the present invention, the lubricating oil composition comprises (C-1) a succinimide compound having a mass average molecular weight of 4,000 to 7,000, preferably 5,000 to 7,000, and (C-2). It is characterized by combining with an succinimide compound having a mass average molecular weight of more than 7,000 to 10,000, preferably 7,100 to 9,600. In the following, the component (C-1) may be referred to as a first succinimide compound, and the component (C-2) may be referred to as a second succinimide compound.
Although not limited, the component (C-1) and a part or all of the component (C-2) may be boronized succinimide.
The component (C) is preferably in an amount of 0.5 to 3.0% by mass, more preferably 0.6 to 2.5% by mass, still more preferably 0.9 to 2.0% by mass with respect to the entire composition. Is contained in the composition. If it is less than the above lower limit, the shudder prevention property may not be ensured. Above the above upper limit, the viscosity at low temperature may increase.

The mass ratio of the component (C-1) to the component (C-2) is not limited, but is preferably (C-2) / (C-1) = 1-10, more preferably 1.5-8. 2 to 6 are preferable, and 2 to 6 are more preferable. In the ratio of the above range, it is possible to achieve a better balance between the friction coefficient and the shader characteristics.
When the amount of (C-1) is insufficient, the shudder prevention property is insufficient at a low temperature, for example, 40 ° C., and there is a problem that this insufficiency becomes apparent early in the durability test.
When the amount of (C-2) is insufficient, the shudder prevention property at a high temperature, for example, 120 ° C. is insufficient, and there is a problem that this insufficiency becomes apparent early in the durability test.

The first and second succinimide compounds in the present invention may be succinimide compounds known as ashless dispersants.

上記式において、Ｒ^１は互いに独立に炭素数４０〜４００のアルキル基またはアルケニル基であり、ｍは１〜２０の整数であり、ｎは０〜２０の整数である。特にはビスタイプのコハク酸イミド化合物が好ましい。ホウ素化コハク酸イミド化合物は、モノタイプ及びビスタイプの併用、２種以上のモノタイプの併用、２種以上のビスタイプの併用であってもよい。コハク酸イミド化合物中の窒素含有量は、限定的ではないが、化合物の質量に対して０．３〜１０質量％が好ましく、さらには０．５〜５質量％が好ましく、特には０．８〜２．５質量％が好ましい。 More specifically, the succinimide compound is a compound in which succinic anhydride is added to a polyamine. There are monotype succinimide compounds and bis-type succinimide compounds, both of which can be used. The monotype succinimide compound can be represented by, for example, the following formula (1). The bis-type succinimide compound can be represented by, for example, the following formula (2).

In the above formula, R ¹ is an alkyl group or an alkenyl group having 40 to 400 carbon atoms independently of each other, m is an integer of 1 to 20, and n is an integer of 0 to 20. In particular, a bis-type succinimide compound is preferable. The boronized succinimide compound may be a combination of monotype and bistype, a combination of two or more monotypes, and a combination of two or more bistypes. The nitrogen content in the succinimide compound is not limited, but is preferably 0.3 to 10% by mass, more preferably 0.5 to 5% by mass, and particularly 0.8 to the mass of the compound. ~ 2.5% by mass is preferable.

The optional boronized succinimide compound is, more specifically, a compound obtained by reacting a succinimide compound as represented by the above formula with a boron compound. Boron compounds include boric acid, boric anhydride, boric acid ester, boron oxide, and boron halide. The boric acid succinimide compound includes a succinimide compound having at least one alkyl group or alkenyl group in the molecule modified (borated) with boric acid, borate or the like. Examples of the alkyl group or alkenyl group include monovalent groups derived from olefin oligomers such as propylene, 1-butene and isobutylene, and co-oligomers of ethylene and propylene.

(C-1) The first succinimide compound has a mass average molecular weight of 4,000 to 7,000. The mass average molecular weight is preferably 5,000 to 7,000, more preferably 5,200 to 6,800. If the molecular weight of the first succinimide compound is less than the above lower limit, the shader characteristics deteriorate.
In the present invention, the mass average molecular weight of the first boronized succinate imide compound is: solvent: THF (tetrahydrofuran), packed column: styrene / divinylbenzene copolymer, set temperature: 40 ° C., set flow rate 1.0 ml / It is a polystyrene-equivalent value measured by an RI (differential refractometer) detector in minutes.

When the boronized succinimide compound is used as the first succinimide compound, the boron content is not limited, but is preferably 0.1 to 3% by mass, more preferably 0.1 to 3% by mass, based on the mass of the compound. It is preferably 2 to 2.5% by mass, more preferably 0.2 to 2% by mass, and particularly preferably 0.2 to 1.5% by mass.

The content of the first succinimide compound in the lubricating oil composition is not limited, but is preferably 0.05 to 2.00% by mass, preferably 0.08 to 2.00% by mass, based on the total mass of the lubricating oil composition. 1.80% by mass is more preferable, and 0.10 to 1.50% by mass is further preferable. If the content is less than the lower limit, sufficient cleanliness may not be ensured, and if the content exceeds the upper limit, sludge may be generated.
As the first succinimide compound, at least one selected from unborated succinimide compound and borated succinimide compound can be used. Therefore, the non-borinated succinimide compound alone or two or more, the boronized succinimide compound alone or two or more, the non-borinated succinimide compound one or more and the boroded succinimide compound 1 It may be any combination of seeds and above.

(C-2) The second succinimide compound has a mass average molecular weight of more than 7,000 to 10,000. The mass average molecular weight is preferably 7,100 to 9,600, more preferably 7,500 to 9,200. When the molecular weight of the second succinimide compound exceeds the above upper limit, the low temperature viscosity of the composition is inconveniently increased.
In the present invention, the mass average molecular weight of the second succinateimide compound is solvent: THF (tetrahydrofuran), packed column: styrene / divinylbenzene copolymer, set temperature: 40 ° C., set flow rate 1.0 ml / min. , A polystyrene-equivalent value measured by an RI (differential refractometer) detector.

When a boronized succinimide compound is used as the second succinimide compound, the boron content is not limited, but is preferably 0.1 to 3% by mass, more preferably 0.1 to 3% by mass, based on the mass of the compound. It is preferably 2 to 2.5% by mass, more preferably 0.2 to 2% by mass, and particularly preferably 0.2 to 1.5% by mass. The nitrogen content in the succinimide compound is not limited, but is preferably 0.2 to 5.0% by mass, more preferably 0.3 to 2.5% by mass, and particularly 0.5 to 2%. .0% by mass is preferable.

The content of the second succinimide compound in the lubricating oil composition is not limited, but is preferably 0.2 to 3.0% by mass, preferably 0.4 to 3.0% by mass, based on the total mass of the lubricating oil composition. 2.5% by mass is more preferable, and 0.6 to 2.0% by mass is further preferable. If it is less than the lower limit value, sufficient cleanliness may not be ensured, and if it exceeds the upper limit value, the low temperature viscosity of the composition is inconveniently increased.
As the second succinimide compound, at least one selected from unborated succinimide compound and borated succinimide compound can be used. Therefore, the non-borinated succinimide compound alone or two or more, the boronized succinimide compound alone or two or more, the non-borinated succinimide compound one or more and the boroded succinimide compound 1 It may be any combination of seeds and above.

The lubricant composition of the present invention may further contain another ashless dispersant in combination with the above component (C-1) and the above component (C-2). Other ashless dispersants typically include succinic acid amide compounds.

In addition to the above components (A) to (C), the lubricating oil composition of the present invention further requires (D) (D-1) amide-based friction modifier, and if necessary, (D-2) boron. A friction modifier consisting of a reaction product of acid or boron oxide with an epoxide is used.
(D) Friction modifier The friction modifier requires (D-1) an amide-based friction modifier, and (D-2) a friction modifier consisting of the reaction product of boric acid or boron oxide and epoxide is required. Used accordingly.
The (D-1) amide-based friction modifier is not limited, but a fatty acid amide compound is preferably used, and in particular, an amide of a linear fatty acid and an aliphatic monoamine or an aliphatic polyamine is used. A fatty acid amide compound having an alkyl group or an alkenyl group having 6 to 30 carbon atoms can be preferably used. More specifically, for example, lauric acid amide, lauric acid diethanolamide, lauric acid monopropanol amide, myristic acid amide, myristic acid diethanolamide, myristic acid monopropanol amide, palmitic acid amide, palmitic acid diethanolamide, palmitic acid mono. Propanolamide, stearic acid amide, isostearic acid amide, stearic acid dimethanolamide, isostearic acid dimethanolamide, stearic acid diethanolamide, isostearic acid diethanolamide, stearic acid monopropanolamide, isostearic acid monopropanolamide, isostearic acid tris (hydroxy) Methyl) methylene amide, oleic acid amide, oleic acid dimethanol amide, oleic acid diethanolamide, oleic acid monopropanol amide, coconut oil fatty acid amide, coconut oil fatty acid diethanolamide, coconut oil fatty acid monopropanol amide, having 12 to 13 carbon atoms. Synthetic mixed fatty acid amides, synthetic mixed fatty acid diethanolamides having 12 to 13 carbon atoms, synthetic mixed fatty acid monopropanol amides having 12 to 13 carbon atoms, and mixtures thereof are particularly preferably used.
This (D-1) amide-based friction modifier is an essential component.

The lubricating oil composition of the present invention does not prevent the inclusion of other friction modifiers as long as the (D-1) amide-based friction modifier is contained as an essential component. For example, any friction modifier such as other ester-based friction modifiers, amine-based friction modifiers, alcohol-based friction modifiers, and molybdenum-based friction modifiers can be included.
Among them, (D-2) a friction modifier composed of a reaction product of boric acid or boron oxide and an epoxide is preferably used because it improves the initial shader characteristics.

ここで、R1、R2、R3及びR4は、それぞれ独立して、水素原子、または1個〜３０個の炭素原子を含有する炭化水素基であり、その少なくとも１個は、炭化水素基である。このR1、R2、R3及びR4のうち任意の２個が、それらが結合される原子と一緒になって環状基（脂環式または複素環式であり得る）を形成していてもよい。
限定的ではないが、R1、R2、R3及びR4のうち、いずれか一つが炭素数6〜30を有する炭化水素基であり、残こりが水素原子であることが好ましい。
炭素数6〜30の炭化水素基としては、限定的ではないが、アルキル基、アルケニル基、アルキニル基、アリール基、等が挙げられるほか、飽和又は不飽和の脂肪酸残基を挙げることができる。
たとえば、飽和脂肪酸残基としては、カブロン酸残基、カプリル酸残基、カプリン酸残基、ラウリン酸残基、ミリスチル酸残基、パルミチル酸残基、ステアリル酸残基及びイソステアリル酸残基が挙げられる。
また、不飽和脂肪酸残基としては、リノール酸残基、α-リノレン酸残基、γ-リノレン酸残基、アラキドン酸残基、ドコサペンタ塩酸残基、パルミトレイン酸残基、バクセン酸残基、パウリン酸残基、オレイン酸残基(オレイル基)、エライジン酸残基、エルカ酸残基、ネルボン酸残基などが挙げられる。 (D-2) A friction modifier composed of a reaction product of boric acid or boron oxide and an epoxide. The friction modifier composed of the reaction product is well known, and is described in, for example, Japanese Patent Application Laid-Open No. 2000-87068. Boric acids include various forms of boric acid (including metaboric acid, HBO ₂ , orthoboric acid, H ₃ BO ₃ , and tetraboric acid, H ₂ B ₄ O ₇ ), and formula (RO) _x B (OH). ) _Y (where x is 1-3, y is 0-2, the sum of x and y is 3, where R is 1-6 carbon atoms. (Alkyl group containing) is an alkyl borate. The epoxide itself, or its equivalent in terms of its reaction, such as diols and halohydrins. It is described in detail in US Pat. No. 4,584,115 and is generally prepared by reacting an epoxide (preferably hydrocarbyl epoxide) with boric acid or boron trioxide. Epoxides can be represented by the following general formula:

Here, R1, R2, R3 and R4 are each independently a hydrogen atom or a hydrocarbon group containing 1 to 30 carbon atoms, and at least one of them is a hydrocarbon group. Any two of the R1, R2, R3 and R4 may be combined with the atoms to which they are attached to form a cyclic group (which may be alicyclic or heterocyclic).
Although not limited, it is preferable that any one of R1, R2, R3 and R4 is a hydrocarbon group having 6 to 30 carbon atoms, and the residue is a hydrogen atom.
Examples of the hydrocarbon group having 6 to 30 carbon atoms include, but are not limited to, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, and the like, as well as saturated or unsaturated fatty acid residues.
For example, saturated fatty acid residues include cabroic acid residues, caprylic acid residues, capric acid residues, lauric acid residues, myristyl acid residues, palmitic acid residues, stearyl acid residues and isostearyl acid residues. Can be mentioned.
The unsaturated fatty acid residues include linoleic acid residue, α-linolenic acid residue, γ-linolenic acid residue, arachidonic acid residue, docosapenta hydrochloride residue, palmitoleic acid residue, vaccenic acid residue, and Paullinic acid residue. Examples thereof include acid residues, oleic acid residues (oleic group), elaidic acid residues, erucic acid residues, and nervonic acid residues.

These epoxides can be _{commercial mixtures of C 14-16} or C _14-18 epoxides, which can be purchased from ELF-ATOCHEM or Union Carbide and can be prepared from the corresponding olefins by known methods. A mixture of boric acid or boron oxide (hereinafter collectively referred to as boric acid) and epoxide or an equivalent thereof (hereinafter collectively referred to as epoxide) is mixed at an appropriate temperature (typically, simply referred to as epoxide). , 80 ° C to 250 ° C) to prepare the reactants. The molar ratio of boric acid to epoxide is generally 4: 1 to 1: 4. A ratio of 1: 1 to 1: 3 is preferable, and 1: 2 is a particularly preferable ratio. In carrying out this reaction, an inert liquid can be used as the reaction medium. The liquid can be toluene, xylene, chlorobenzene, dimethylformamide, and the like. The reaction forms water, which is typically distilled off during this reaction operation. Hydroxides can be used to facilitate this reaction. The epoxy ring may be opened in the reaction product. The method for preparing the reactive organism is also described in Japanese Patent Application Publication No. 57-200496.
The compound thus obtained is effectively used as a friction modifier and provides good shader properties.

Examples of (D-2) are not limited, but are preferably oleic acid chlorides of fatty acid epoxy esters or ring-opened products thereof. Acyl chloride, glycidyl myristate borate, glycidyl palmitate borate, glycidyl oleate borate, ethylene oleate oxide borate, glycidyl stearate borate, isostearic Examples thereof include a borate product of glycidyl acid acid, a borate product of glycidyl laurate, and the like.

The amount of (D-1) added is not limited, but is preferably 0.01 to 5% by mass, more preferably 0.02 to 4% by mass, based on the total mass of the lubricating oil composition. , 0.1 to 3% by mass, more preferably.
(D-2) is not essential, but when added, it is preferably 0.01 to 5% by mass, more preferably 0.02 to 4% by mass, based on the total mass of the lubricating oil composition. It is preferably 0.1 to 3% by mass, more preferably 0.1 to 3% by mass.

The lubricating oil composition of the present invention preferably further contains (E) a metal cleaning agent and / or (F) an ether sulfolane compound in addition to the above components (A) to (D).

(E) Metal cleaning agent Examples of the metal cleaning agent include a cleaning agent having an alkali metal or an alkaline earth metal. Examples include, but are not limited to, sulfonates containing alkali metals or alkaline earth metals, salicylates containing alkali metals or alkaline earth metals, and phenates containing alkali metals or alkaline earth metals. Examples of the alkali metal or alkaline earth metal include, but are not limited to, magnesium, barium, sodium, and calcium.

The sulphonate containing an alkali metal or an alkaline earth metal is preferably, but not limited to, calcium sulphonate and magnesium sulphonate.

The salicylate containing an alkali metal or an alkaline earth metal is not limited, but calcium salicylate and magnesium salicylate are preferably used.

The phenate containing an alkali metal or an alkaline earth metal is preferably, but not limited to, calcium phenate and magnesium phenate.

The amount of alkali metal or alkaline earth metal contained in the metal cleaning agent is not limited, but is preferably 0.1 to 20% by mass, more preferably 0.5 to 15% by mass, based on the mass of the metal cleaning agent. , 1.0 to 15% by mass is more preferable.

The metal cleaning agent preferably has a total base value of 10 to 500 mgKOH / g, more preferably 50 to 400 mgKOH / g, and even more preferably 150 to 400 mgKOH / g. In particular, when it is 200 to 400 mgKOH / g, more preferably 300 to 400 mgKOH / g, and most preferably 310 to 400 mgKOH / g, the cleaning effect is high and the generation of sludge is suppressed. Most preferable because it is possible.

The metal cleaning agent is contained in the lubricating oil composition in an arbitrary ratio. For example, it is 0 to 5% by mass, more preferably 0.1 to 2% by mass, and further preferably 0.2 to 1% by mass, based on the total mass of the lubricating oil composition.

As the metal cleaning agent, one type may be used alone, or two or more types may be used in combination. The type is not limited even when used in combination, and may be, for example, sulfonate compounds, salicylate compounds, or phenate compounds, but may be a combination of a sulfonate compound and a salicylate compound, a sulfonate compound and a phenate compound, or a salicylate compound and a phenate compound. ..

上記式において、Ｒは炭素数１〜２０のアルキル基であり、好ましくは炭素数８〜１６のアルキル基である。 (F) Ether Sulfolane Compound The lubricating oil composition of the present invention can further secure an appropriate seal rubber swelling property by containing the ether sulfolane compound. The ether sulfolane compound is the following compound.

In the above formula, R is an alkyl group having 1 to 20 carbon atoms, preferably an alkyl group having 8 to 16 carbon atoms.

The blending amount of the ether sulfolane compound is preferably 0 to 5% by mass, more preferably 0.1 to 2% by mass, and even more preferably 0.2 to 1% by mass, based on the total mass of the lubricating oil composition.

The lubricating oil composition of the present invention may further contain other additives other than the above (B) to (F). For example, oil-based agents, anti-wear agents, extreme pressure agents, rust inhibitors, anti-friction agents, antioxidants, anti-corrosion agents, metal inactivating agents, flow point lowering agents, defoaming agents, coloring agents, etc. And package additives for automatic transmission fluids. Various packaging additives for lubricating oils containing at least one of these can also be added.

In particular, as the extreme pressure agent, a phosphorus-based extreme pressure agent can be used, and an acidic phosphoric acid ester, an acidic phosphorous acid phosphorous acid ester, a phosphoric acid ester or a phosphorous acid ester, and these. It is preferable that at least one of the amine salts, phosphoric acid or phosphorous acid of the above is selected.
In addition, at least one selected from, but not limited to, acidic phosphoric acid ester, acidic phosphoric acid phosphorous acid ester, phosphoric acid ester or phosphorous acid ester, and amine salts thereof, and phosphoric acid or phosphorous acid. It is preferable that at least one type is selected from phosphoric acid.
Further, but not limited to, at least one selected from acidic phosphoric acid ester, acidic phosphorous acid phosphorous acid ester, phosphoric acid ester or phosphorous acid ester, and amine salts thereof, and phosphoric acid or phosphorous acid. It is preferable that at least one type is selected from phosphoric acid.
Further, a combination of an acidic phosphoric acid ester and one or more compounds selected from phosphoric acid or phosphite is also preferable, and among the acidic phosphoric acid esters, acidic phosphoric acid butyl ester, acidic phosphoric acid hexyl ester, and acidic phosphoric acid are particularly preferable. It is preferable to use octyl ester and acidic phosphoric acid dodecyl ester.
The amount of these phosphorus-based extreme pressure agents is not limited, but is preferably 0.01 to 2.5% by mass, more preferably 0.02 to 1.5% by mass, and 0, based on the total mass of the lubricating oil composition. It is more preferably .02 to 1.0% by mass.

Kinematic viscosity at 100 ° C. of the lubricating oil composition of the present invention, but are not limited, it is preferably from 3 to 10 mm ² / s, more preferably 3 to 8 mm ² / s, 4 further preferably ~7.5mm ² / s, and still more preferably from 4 to 6 mm ² / s. If the kinematic viscosity of the lubricating oil composition at 100 ° C. is less than the above lower limit value, it may not be possible to sufficiently secure the friction coefficient. Further, if it exceeds the above upper limit value, the shadder characteristics may deteriorate.

The viscosity index of the lubricating oil composition of the present invention is not limited, but is preferably 150 or more, and more preferably 160 or more. If the viscosity index of the lubricating oil composition is less than the above lower limit, it may not be possible to sufficiently secure the fuel efficiency characteristics at 40 ° C. The upper limit is not limited, but is preferably 250.

Although the lubricating oil composition of the present invention has a low viscosity, it has an effect that it has a sufficiently large coefficient of friction between metals and can secure shadder characteristics. Further, as described above, the shear stability can be ensured by further specifying the composition of the base oil and the viscosity index improver according to the present invention. Furthermore, by containing the ether sulfolane compound, it is possible to secure an appropriate seal rubber swelling property. Furthermore, by using a metal cleaning agent having a total base value of 200 to 400 mgKOH / g, it is possible to suppress the generation of sludge while ensuring cleanliness. The lubricating oil composition of the present invention can be suitably used for continuously variable transmissions.

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 components used in the examples and comparative examples are as follows. Each component shown below was mixed with the composition shown in Table 1 or Table 2 to prepare a lubricating oil composition. In the following, KV100 means kinematic viscosity at 100 ° C., VI means viscosity index, and PMA means polymethacrylate. The coefficient of friction is the ratio of the coefficient of friction when the composition (commercially available product) of Comparative Example 8 is 1.
(A) Lubricating oil base oil / mineral oil 1: Highly hydrorefined paraffin-based base oil (KV100 = 3.1 mm ² / s, VI = 112)
-Mineral oil 2: Highly hydrorefined paraffin-based base oil (KV100 = 4.2 mm ² / s, VI = 122)
-Mineral oil 3: Highly hydrorefined paraffin-based base oil (KV100 = 4.2 mm ² / s, VI = 134)
-Mineral oil 4: Hydrorefined paraffin-based base oil (KV100 = 2.2 mm ² / s, VI = 109)
-Mineral oil 5: Hydrorefined paraffin-based base oil (KV100 = 2.5 mm ² / s, VI = 99)
-Synthetic base oil 1: Poly-α-olefin (KV100 = 10 mm ² / s, VI = 137)
-Synthetic base oil 2: Poly-α-olefin (KV100 = 40 mm ² / s, VI = 147)
-Synthetic base oil 3: Ethylene-α-olefin copolymer (KV100 = 10 mm ² / s, VI = 150)
-Synthetic base oil 4: Ethylene-α-olefin copolymer (KV100 = 40 mm ² / s, VI = 155)

(B) Viscosity index improver-PMA-based viscosity index improver 1 (Mw = 30,000),-(CH _2- C (CH ₃ ) (COOR)) _n -structure.

(C) Borylated succinimide compound (C-1)
Borylated succinimide compound 1 (Mw = 5,600, B: 0.34 wt%, N = 1.58 wt%, in formula (2), R1 is a mixture of polyisobutenyl groups, n = 4-12)
Borylated succinimide compound 3 (Mw = 4,600, B: 1.8 wt%, N = 2.35 wt%, in formula (2), R1 is a mixture of polyisobutenyl groups, n = 4-12)
(C-2)
Borylated succinimide compound 2 (Mw = 8,500, B: 0.23 wt%, N = 0.88 wt%, in formula (2), R1 is a polyisobutenyl group, a mixture of n = 4-12))

(D) Friction modifier
(D-1) Ingredients Amide-based friction modifier ・ (D-1a) Reaction product of isostearic acid and tris (hydroxymethyl) aminomethane ・ (D-1b) Isostearic acid diethanolamide ・ (D-1c) Diethanolami stearate Do- (D-1d) oleic acid diethanolamide- (D-1e) lauric acid diethanolamide
(D-2) Component Friction modifier consisting of boron chloride epoxide or its ring-opened product ・ (D-2a) Boronized product of ethylene oxide of oleate ・ (D-2b) Boronized product of ethylene oxide of stearate ・ (D-2c) Olein Boronized glycidyl acid (D-2d) Boronized glycidyl laurate

(E) Metal detergent / Ca sulfonate (total base value 350 mgKOH / g)
-Ca salicylate (total base value 300 mgKOH / g)
-Mg salicylate (total base value 400 mgKOH / g)

(F) Ether sulfolane compound-LUBRIZOL 730 (in the following formula, R ¹ = C ₁₀ H ₂₁ compound)

(F) Other additives
Anti-wear agents, friction modifiers, antioxidants, defoamers, metal deactivators, and colorants

Claims (15)

(A) Lubricating oil base oil,
(C) (C-1) A succinimide compound or a borated succinimide compound having a mass average molecular weight of 4,000 to 7,000,
(C-2) Succinimide compound or borated succinimide compound having a mass average molecular weight of more than 7,000 to 10,000,
The mass ratio of the component (C-1) to the component (C-2) is (C-2) / (C-1) = 1.5 to 8, and (D) (D-1) amide system. Friction modifier
A lubricating oil composition characterized that you contain,
A poly-α-olefin or α-olefin copolymer having a ^{kinematic viscosity of 6 to 80 mm 2} / s at 100 ° C. as a part or all of the component (A) was added to the total mass of the lubricating oil composition. Containing in ~ 30% by mass,
The lubricating oil composition. (D) (D-2) The lubricating oil composition according to claim 1, further containing a friction modifier composed of a reaction product of boric acid or boron oxide and an epoxide. (B) The lubricating oil composition according to claim 1 or 2, further comprising a polymethacrylate having a mass average molecular weight of 15,000 to 40,000. The lubricating oil according to any one of claims 1 to 3, wherein the component (C-1) and a part or all of the component (C-2) are boronized succinimide. Composition. The (C-1) component and / or the (C-2) component each contain 0.1 to 3% by mass of boron with respect to the mass of the (C-1) component or the (C-2) component. The lubricating oil composition according to claim 4, which is contained in an amount. The lubrication according to any one of claims 1 to 5, wherein the mass ratio of the component (C-1) to the component (C-2) is (C-2) / (C-1) = 2-6. Oil composition. The lubricating oil composition according to any one of claims 1 to 6, wherein the amount of the component (C) is 0.5 to 3.0% by mass based on the entire lubricating oil composition. The lubricating oil composition according to any one of claims 1 to 7 , wherein the succinimide compound is represented by the following formula (1) or (2).

In the above formula, R ¹ is an alkyl group or an alkenyl group having 40 to 400 carbon atoms independently of each other, m is an integer of 1 to 20, and n is an integer of 0 to 20. The lubricating oil composition according to any one of claims 1 to 8 , which has a kinematic viscosity of 3 to 10 mm ^{2 / s at 100 ° C.} The lubricating oil composition according to any one of claims 1 to 9 , which has a viscosity index of 150 or more. Any one of claims 1 to 10 , wherein (D-1) is selected from at least one amide compound derived from a fatty acid having an alkyl group or an alkenyl group having 6 to 30 carbon atoms. The lubricating oil composition according to. Claims 2 to 2, wherein (D-2) is selected from at least one kind of reaction product of epoxide represented by the following general formula and boric acid or boron oxide, or a ring-opening product thereof. The lubricating oil composition according to any one of 11.

(R1, R2, R3, and R4 each independently represent a hydrogen atom or a hydrocarbon group containing 1 to 30 carbon atoms, of which at least one is a hydrocarbon group.) The lubricating oil composition according to any one of claims 1 to 12 , further comprising (E) a metal cleaning agent. The lubricating oil composition according to any one of claims 1 to 13 , further comprising (F) an ether sulfolane compound. The lubricating oil composition according to any one of claims 1 to 14 , which is for a continuously variable transmission.