JP5941342B2 - Lubricating oil composition - Google Patents

Description

  The present invention relates to a lubricating oil composition, and more particularly, a torque transmission device that does not deteriorate in performance of preventing shudder vibration even in long-term use and requires a high transmission torque capacity such as a wet clutch or a wet brake, The present invention relates to a lubricating oil composition suitable for automatic transmissions and continuously variable transmissions that require good transmission characteristics.

  Wet clutches and brakes are used in various machines, and their control is greatly influenced by the lubricating oil used there. Basically, it is required to have a high coefficient of friction at the time of sliding, alleviation of shock when the sliding stops, and suppression of vibration at constant speed or variable speed (for example, vibration of stick-slip or shudder). This is particularly important for driving force transmission devices such as torque splitters, automatic transmissions, continuously variable transmissions, and the like mounted on automobiles.

  Many automatic transmissions and continuously variable transmissions have a torque converter, and engine torque is transmitted to the transmission via lubricating oil. Due to the structure of the torque converter, power cannot be transmitted unless there is a differential rotation between the input side (engine side) and the output side (transmission side), and this differential rotation causes a reduction in power transmission efficiency of the transmission. . With the goal of reducing carbon dioxide emissions against the background of global environmental problems, the demand for fuel savings in automobiles is increasing, and transmissions are required to improve power transmission efficiency more than ever before. However, in recent years, a torque-converter with a built-in lock-up clutch has been widely used as a means to transmit engine torque directly to the transmission mechanism in accordance with driving conditions in addition to power transmission via lubricating oil. ing.

  However, when the lock-up clutch is operated, engine torque fluctuations deteriorate the ride comfort. With the conventional lock-up mechanism, the lock-up clutch is operated only in the high speed range where the engine torque fluctuation is small and is operated in the low speed range. It wasn't. For this reason, the transmission loss of the torque converter cannot be prevented in a low speed region such as when starting, and the fuel efficiency improvement effect was not obtained so much.

  In order to reduce this transmission loss, recently, a slip control system has been introduced in which a lock-up clutch is operated even in a low-speed range and engine torque fluctuations are absorbed by the relative slip of the clutch. However, when the clutch is controlled to slip, an abnormal vibration called a shudder occurs on the friction surface of the lock-up clutch, which causes a problem that the ride comfort of the automobile is greatly impaired. To prevent the occurrence of shudder, in the lockup clutch, there is a need for a lubricating oil with improved anti-shudder performance with improved μ-V characteristics so that the coefficient of friction (μ) increases as the sliding speed (V) increases. It has been. The expansion of the low-speed region where slip control is performed is further advanced, and further improvement in maintainability of the anti-shudder performance is desired.

  In addition, automatic transmissions and continuously variable transmissions have a wet transmission clutch in the transmission mechanism and the forward / reverse switching mechanism. If the friction characteristics of the transmission clutch are poor, a shock will occur at the time of shifting and the ride comfort of the vehicle will be reduced. Will be uncomfortable. For this reason, the lubricating oil for automatic transmissions is required to have good speed change characteristics in order to reduce shock when the speed change clutch is engaged. One way to improve the maintainability of the anti-shudder performance and the transmission characteristics is to add a large amount of friction modifier, but depending on the type of friction modifier, the friction coefficient of the wet clutch can be significantly reduced. In some cases, the transmission torque capacity cannot be secured. There is generally a trade-off relationship between maintainability of shudder prevention and transmission characteristics and transmission torque capacity, and development of a lubricating oil composition that satisfies both of these performances is desired.

  Accordingly, the present invention has been made in view of such a situation, and the object thereof is a novel that maintains the anti-shudder performance even during long-term use, and has a high torque transmission capacity and good transmission characteristics of a wet clutch. It is to provide a lubricating oil composition.

  As a result of intensive studies to solve the above problems, the inventors of the present invention contain an ester compound obtained by subjecting a lubricating base oil to a dehydration condensation reaction of 1 equivalent of hydrocarbyldiol and 1 equivalent of carboxylic acid. As a result, the present inventors have found that the above-mentioned lubricating oil composition can solve the above-mentioned problems and have completed the present invention.

（一般式（１）において、Ｒ_１、Ｒ_２のうち何れか一方は炭素数１２以上のヒドロカルビル基、もう一方は水素または炭素数１〜３０のヒドロカルビル基であり、Ｒ_１、Ｒ_２ともに炭素数３以上の場合は飽和アミン結合（＞Ｎ−）、チオエーテル結合（−Ｓ−）、エーテル結合（−Ｏ−）を含有していても良く、Ｒ_３の炭素数は０〜３である。） That is, the present invention relates to an ester compound represented by the following general formula (1) obtained by subjecting a lubricating base oil to (A) a dehydration condensation reaction of 1 equivalent of hydrocarbyldiol and 1 equivalent of carboxylic acid, and (B) The present invention relates to a lubricating oil composition comprising an antiwear agent containing phosphorus.

(In General Formula (1), one of R ₁ and R ₂ is a hydrocarbyl group having 12 or more carbon atoms, the other is hydrogen or a hydrocarbyl group having 1 to 30 carbon atoms, and both R ₁ and R ₂ are carbon atoms. When the number is 3 or more, it may contain a saturated amine bond (> N-), a thioether bond (-S-), or an ether bond (-O-), and R ₃ has 0 to 3 carbon atoms. )

In the lubricating oil composition of the present invention, R ₁ in the general formula (1) is an alkyl group or alkenyl group having 12 to 30 carbon atoms, R ₂ is hydrogen or a methyl group, and R _{3 has} a carbon number. It is preferably 0 or 1, respectively.

  The lubricating oil composition of the present invention preferably further contains one or more kinds of (C) a friction modifier and / or (D) a metal detergent.

  The lubricating oil composition of the present invention is preferably used for a torque transmission device having a wet clutch and / or a wet brake, an automatic transmission, or a continuously variable transmission.

  The lubricating oil composition of the present invention maintains anti-shudder performance even after long-term use, and has a high torque transmission capacity and good speed change characteristics of a wet clutch.

Hereinafter, the contents of the present invention will be described in more detail.
As the lubricating base oil in the lubricating oil composition of the present invention, any mineral oil and / or synthetic oil used as a base oil for ordinary lubricating oils can be used.
The mineral oil is not particularly limited. For example, a lubricating oil fraction obtained by subjecting crude oil to atmospheric distillation and vacuum distillation can be desolvated, solvent extracted, hydrocracked, solvent dewaxed, catalytic dewaxed, Oils such as paraffinic and naphthenic oils, normal paraffins, and the like that are refined by appropriately combining hydrorefining, sulfuric acid washing, purification treatment such as clay treatment, and the like can be used. In particular, it is desirable to improve the low-temperature fluidity by removing the wax after processing such as solvent purification or hydrorefining. Further, low temperature fluidity of the lubricating oil composition, from the possible to improve the oxidation stability, n-d-m method (ASTM-D3238-80)% _{C P} defined by preferably 60 or more, more preferably 70 not less than,% C _a is preferably 10 or less, more preferably 5 or less, a viscosity index of preferably 95 or more, more preferably it is desirable to use more than 100 mineral oil.

Although there is no restriction | limiting in particular as synthetic oil, Poly-alpha-olefin (1-octene oligomer, 1-decene oligomer, ethylene-propylene oligomer etc.) or its hydride, isobutene oligomer or its hydride, isoparaffin, alkylbenzene, alkyl Naphthalene, diester (ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, di2-ethylhexyl sebacate, etc.), polyol ester (trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol 2- Ethyl hexanoate, pentaerythritol pelargonate, etc.), polyoxyalkylene glycol, dialkyl diphenyl ether, and polyphenyl ether Etc. can be used.
Considering the solubility of the additive, these synthetic oils are preferably mixed with mineral oil or used by mixing two or more synthetic oils rather than using them alone. The kinematic viscosity of the lubricating base oil using these mineral oils and / or synthetic oils is not particularly limited and is arbitrary. Usually, the kinematic viscosity at 100 ° C. is preferably 1 to ²⁰ mm ² / s, more preferably 1 .5 to 10 mm ² / s.

  The component (A) in the lubricating oil composition of the present invention is an ester compound represented by the following general formula (1) obtained by dehydrating condensation reaction of 1 equivalent of hydrocarbyldiol and 1 equivalent of carboxylic acid.

In General Formula (1), one of R ₁ and R ₂ is a hydrocarbyl group having 12 or more carbon atoms, the other is hydrogen or a hydrocarbyl group having 1 to 30 carbon atoms, and both R ₁ and R _{2 have} carbon atoms. If 3 or more saturated amine bonds (> N-), thioether bond (-S-), may contain an ether bond (-O-), the number of carbon atoms of _{R 3} is 0-3.

In the general formula (1), R ₁ and R ₂ may be the same or different, and at least one of the hydrocarbyl groups has 12 or more carbon atoms, preferably 30 or less, more preferably 25 or less carbon atoms. It is a hydrogen group. These may be linear or branched, but are preferably linear.
When the carbon number of any hydrocarbyl group of R ₁ and R ₂ is less than 12, the effect of improving the shudder vibration prevention is low, and when it exceeds 30, the solubility is deteriorated and the shudder vibration prevention is improved. In this case, a sufficient amount that exhibits an effect cannot be blended.
In the general formula (1), when R ₁ is a hydrocarbyl group having 12 or more carbon atoms and R ₂ is methyl, the adsorptivity is the highest and the effect is increased, which is preferable.

R ₃ is a divalent hydrocarbon group having 0 to ₃ carbon atoms. More preferably, it is 0-1. Exceeding 3 is not preferable because the anti-shudder property decreases. However, the carbon number of R ₃ being 0 means that carbons on both sides of R ₃ are directly bonded.

  The ester compound represented by the general formula (1) used as the component (A) is obtained by subjecting 1 equivalent of hydrocarbyl diol and 1 equivalent of carboxylic acid to a dehydration condensation reaction.

  As the hydrocarbyl diol used for the synthesis of the component (A), divalent alkyl or alkenyl diols having 2 to 30 carbon atoms are used. These alkyl groups or alkenyl groups may be linear or branched, but are preferably linear. The position of the double bond of the alkenyl group is arbitrary. The number of carbons between the two hydroxyl groups is 2 or more and 5 or less, and one hydroxyl group is at the end of the molecule.

The hydrocarbyl diol is determined depending on the type of carboxylic acid used.
That is, in the general formula (1), when R ₁ is 12 or more carbon atoms, hydrocarbyl diol to be used, as long as the number of carbon atoms between the two hydroxyl groups of 2 to 5, especially for R ₂ Although there is no limitation, when R ₁ has less than 12 carbon atoms, the number of carbon atoms between the two hydroxyl groups is 2 or more and 5 or less, and the hydrocarbyl diol in which the hydrocarbyl group of R ₂ has 12 or more carbon atoms Used.

  Specific examples of the hydrocarbyl diol used for the synthesis of the component (A) include ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, neopentyl til glycol, 1,3-propanediol, 1,4-butanediol, 1,2-butanediol, 2-methyl-1,3-propanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,2- Hexanediol, 1,3-hexanediol, 1,4-hexanediol, 2-ethyl-2-methyl-1,3-propanediol, 2-methyl-2,4-pentanediol, 1,2-heptanediol, 1,3-heptanediol, 1,4-heptanediol 2-methyl-2-propyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 1,2-octanediol, 1,3-octanediol, 1,4-octanediol, 1,2-nonanediol, 1,3-nonanediol, 1,4-nonanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,2-decanediol, 1,3-decanediol, 1,4-decanediol, 1,2-undecanediol, 1,3-undecanediol, 1,4-undecanediol, 1,2-dodecanediol, 1,3-dodecanediol, 1,4-dodecanediol, 1 , 2-tridecanediol, 1,3-tridecanediol, 1,4-tridecanediol, 1,3-tetradecanediol, 1,4-tetradecane Diol, 1,4-heptadecanediol, 1,2-tetradecanediol, 1.2-hexadecanediol, 1.3-hexadecanediol, 1.4-hexadecanediol, 1,2-heptadecanediol, 1,3- Heptadecanediol, 1,4-heptadecanediol, 1,2-octadecanediol, 1,3-octadecanediol, 1,4-octadecanediol, 1,2-nonadecanediol, 1,3-nonadecanediol, 1 , 4-nonadecanediol, 1,2-icosadecanediol, 1,3-icosadecanediol, 1,4-icosadecanediol, and the like.

  (A) As carboxylic acid used for the synthesis | combination of a component, C2-C32 carboxylic acid is used. Specifically, acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, hebutanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, Mention may be made of margaric acid, stearic acid, oleic acid, nonadecanoic acid, eicosanoic acid and derivatives thereof.

In the present invention, as the ester compound of the general formula (1), any one of R ₁ and R ₂ is a hydrocarbyl group having 12 or more carbon atoms, and the other is hydrogen or a hydrocarbyl group having 1 to 30 carbon atoms. Although a certain compound is used, R ₁ is preferably a hydrocarbyl group having 12 or more carbon atoms, particularly preferably a carboxylic acid having 14 to 20 carbon atoms or a derivative thereof. In this case, R ₂ is hydrogen or a hydrocarbyl group having 1 to 30 carbon atoms, and particularly preferably a methyl group or an ethyl group. R ₃ preferably has 0 or 1 carbon atoms.
Therefore, as the component (A) in the lubricating oil composition of the present invention, the general formula (mycolic acid, palmitic acid, stearic acid, or oleic acid is used as the carboxylic acid, and ethylene glycol or propylene glycol is used as the hydrocarbyl diol. The ester compound represented by 1) is preferred.

  The production method of the general formula (1) of the present invention can be synthesized by a so-called general esterification reaction. The most common method is synthesis by dehydration condensation reaction using hydrocarbyldiol and carboxylic acid as raw materials, but the corresponding carboxylic acid halide or anhydride may be used instead of carboxylic acid, and other catalysts may be used. There is no limitation on the synthetic route such as the reaction used. However, in any synthesis route, when hydrocarbyldiol is used as a raw material, a compound produced by esterification at two sites is mixed as a by-product, and thus purification using silica gel column chromatography or the like is required. Although it is not necessary to completely separate the by-product by purification, it is preferable that at least 90% or more of the compound of the general formula (1) of the present invention is contained.

  In the lubricating oil composition of the present invention, the content of the component (A) is arbitrary, but is preferably 0.01% by mass or more, more preferably 0.1% by mass based on the total amount of the lubricating oil composition. More preferably, it is 0.2% by mass or more, and most preferably 0.5% by mass or more. On the other hand, it is preferable that it is 6 mass% or less, More preferably, it is 4 mass% or less, More preferably, it is 2 mass% or less. When the content of the component (A) is less than 0.01% by mass, the effect of maintaining the anti-shudder performance and good transmission characteristics is inferior. When the content exceeds 6% by mass, the effect corresponding to the addition amount is not obtained. Therefore, it is not preferable respectively.

The component (B) in the lubricating oil composition of the present invention is an antiwear agent containing phosphorus, and any compound that is usually used as a phosphorus antiwear agent for lubricating oils can be used. For example, phosphoric acid, alkyldithiophosphoric acid, zinc alkyldithiophosphate, phosphoric acid monoesters, phosphoric acid diesters, phosphoric acid triesters, phosphorous acid monoesters, phosphorous acid diesters, phosphorous acid triesters , And salts of these esters with amines or alkanolamines can be used, and one or two or more compounds arbitrarily selected from these can be used.
In the lubricating oil composition of the present invention, the component (B) can contain any amount, but the content is 0.005% by mass or more as a phosphorus element based on the total amount of the lubricating oil composition. Is preferable, more preferably 0.01% by mass or more, and still more preferably 0.02% by mass or more. On the other hand, it is preferable that it is 0.2 mass% or less as a phosphorus element, More preferably, it is 0.15 mass% or less, More preferably, it is 0.1 mass% or less. When the content of the component (B) is less than 0.005% by mass, a sufficient intermetal friction coefficient cannot be obtained, or there is no effect on wear resistance, and when it exceeds 0.2% by mass, oxidation stability is obtained. Since the properties deteriorate, each is not preferable.

  In the present invention, by blending the component (A) and the component (B) with the lubricating base oil, a lubricating oil composition having excellent anti-shudder performance and high torque transmission capacity can be obtained. However, you may mix | blend (C) friction modifier and / or (D) metal type detergent individually or in combination of several types. By blending these into the lubricating oil composition of the present invention, it is possible to obtain a lubricating oil composition with better initial transmission characteristics while maintaining transmission torque capacity and anti-shudder performance.

  As the friction modifier that can be used in combination with the lubricating oil composition of the present invention, any compound that is usually used as a friction modifier for lubricating oils can be used, for example, an alkyl group or alkenyl group having 6 to 30 carbon atoms. An amine compound, a fatty acid amide, a fatty acid metal salt, or the like having (a particularly preferred alkyl group or alkenyl group having 6 to 30 carbon atoms having at least one linear alkyl group or linear alkenyl group in the molecule) is exemplified.

Among the amine compounds described above, succinimide and the like which are a reaction product with polyamine are also included. These include those modified with boron compounds and phosphorus compounds.
Examples of the amine compound include linear or branched, preferably linear aliphatic monoamines having 6 to 30 carbon atoms, linear or branched, preferably linear aliphatic polyamines, and aliphatic groups. Examples include alkylene oxide adducts of amines, salts of these amine compounds with phosphate esters or phosphites, or boric acid modified products of (phosphite) phosphate salts of these amine compounds.
Further, alkylene oxide adducts of amine compounds; salts of these amine compounds with phosphates (for example, di2-ethylhexyl phosphate) and phosphites (for example, bis (2-ethylhexyl) phosphite) A boric acid modified product of a (phosphite) phosphate salt of these amine compounds; or a mixture thereof is particularly preferably used.

  Examples of fatty acid amides include linear or branched, preferably linear fatty acids having 7 to 31 carbon atoms, and amides of aliphatic monoamines or aliphatic polyamines. More specifically, for example, , Lauric acid amide, lauric acid diethanolamide, lauric acid monopropanolamide, myristic acid amide, myristic acid diethanolamide, myristic acid monopropanolamide, palmitic acid amide, palmitic acid diethanolamide, palmitic acid monopropanolamide, stearic acid amide, Stearic acid diethanolamide, stearic acid monopropanolamide, oleic acid amide, oleic acid diethanolamide, oleic acid monopropanolamide, coconut oil fatty acid amide, coconut oil fatty acid diethanolamide, coconut oil fatty acid monop Panoruamido, synthetic mixed fatty acid amides 12 to 13 carbon atoms, synthetic mixed fatty acid diethanolamide 12 to 13 carbon atoms, synthetic mixed fatty acid mono-propanol amide 12 to 13 carbon atoms, and mixtures thereof are particularly preferred.

  Examples of the fatty acid metal salt include an alkaline earth metal salt (magnesium salt, calcium salt, etc.) or zinc salt of a linear or branched, preferably linear fatty acid having 7 to 31 carbon atoms, More specifically, for example, calcium laurate, calcium myristate, calcium palmitate, calcium stearate, calcium oleate, palm oil fatty acid calcium, synthetic mixed fatty acid calcium having 12 to 13 carbon atoms, zinc laurate, zinc myristate, Particularly preferred are zinc palmitate, zinc stearate, zinc oleate, coconut oil fatty acid zinc, synthetic mixed fatty acid zinc having 12 to 13 carbon atoms, and mixtures thereof.

  In the present invention, one kind or two or more kinds of compounds arbitrarily selected from these friction modifiers can be contained in any amount, but usually the content thereof is a lubricating oil composition. It is preferable that it is 0.01-5 mass% on the basis, and 0.03-3 mass% is more preferable.

  As the metal-based detergent that can be used in combination with the lubricating oil composition of the present invention, any compound that is usually used as a metal-based detergent for lubricating oil can be used. For example, an alkali metal or alkaline earth metal Sulfonate, phenate, salicylate, naphthenate and the like can be used alone or in combination of two or more in the composition of the present invention. Examples of the alkali metal include sodium and potassium, and examples of the alkaline earth metal include calcium and magnesium. Further, as a specific metal detergent, calcium or magnesium sulfonate, phenate, and salicylate are preferably used. Of these, calcium sulfonate is preferable.

  The total base number of these metal detergents is 0 to 500 mg KOH / g, and the amount added is 0.001 to 0.5 mass in terms of alkali metal or alkaline earth metal element based on the total amount of the composition. The upper limit is preferably 0.1% by mass or less, and 0.05% by mass or less from the viewpoint of preventing a decrease in the coefficient of friction due to clogging of the friction material of the clutch plate. It is particularly preferred.

  The lubricating oil composition of the present invention has a known lubricating oil additive such as an ashless dispersant, a viscosity index improver, an extreme pressure additive, an antioxidant, a corrosion inhibitor, an antifoaming agent for the purpose of further enhancing the performance. Various additives typified by colorants, colorants and the like can be blended singly or in combination.

  As the ashless dispersant that can be used in combination with the lubricating oil composition of the present invention, any compound that is usually used as an ashless dispersant for lubricating oil can be used. For example, it has 40 to 400 carbon atoms, preferably 60 to 60 carbon atoms. A nitrogen-containing compound having at least one alkyl group or alkenyl group having 350 in the molecule, a bis-type or mono-type succinimide having an alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350 carbon atoms, and these Examples include modified products in which the above-described boric acid, phosphoric acid, carboxylic acid or derivatives thereof, sulfur compounds, etc. are allowed to act, and one or two or more compounds arbitrarily selected from these are used in combination can do.

  The alkyl group or alkenyl group herein may be linear or branched, but specific examples include olefin oligomers such as propylene, 1-butene and isobutylene, and ethylene / propylene copolymers. Examples include branched alkyl groups and branched alkenyl groups derived from oligomers. Polybutenyl groups obtained by polymerizing a butene mixture or high-purity isobutylene with an aluminum chloride catalyst or a boron fluoride catalyst, etc. It is preferable that the halogen compound is removed, and most preferable.

  When the carbon number of these alkyl groups or alkenyl groups is less than 40, the clean dispersion performance is poor. On the other hand, when the carbon number of the alkyl groups or alkenyl groups exceeds 400, the low-temperature fluidity of the lubricating oil composition deteriorates. Therefore, it is not preferable respectively. Moreover, although content of these compounds is arbitrary, it is preferable that it is 0.1-10 mass% on the basis of lubricating oil composition whole quantity basis, and 1-8 mass% is more preferable. In the present invention, as the ashless dispersant used in combination, the transmission characteristics are further improved, so that the succinimide having a polybutenyl group having a weight average molecular weight of 700 to 3,500, preferably 900 to 2,000, and / or these It is particularly preferable to blend a boric acid modifying compound. Moreover, it is preferable to blend boric acid-modified succinimide into the ashless dispersant, and further to blend boric acid-modified succinimide as one component, in order to improve the peeling prevention property of the wet clutch. preferable.

  Specific examples of the viscosity index improver that can be used in combination with the lubricating oil composition of the present invention include so-called copolymers of one or more monomers selected from various methacrylic acid esters or hydrogenated products thereof. Examples thereof include a non-dispersed viscosity index improver, or a so-called dispersed viscosity index improver obtained by copolymerizing various methacrylic esters containing a nitrogen compound. Specific examples of other viscosity index improvers include non-dispersed or dispersed ethylene-α-olefin copolymers (the α-olefin can be exemplified by propylene, 1-butene, 1-pentene, etc.) and hydrides thereof. , Polyisobutylene and hydrogenated products thereof, styrene-diene hydrogenated copolymer, styrene-maleic anhydride ester copolymer, and polyalkylstyrene.

  The molecular weight of these viscosity index improvers needs to be selected in consideration of shear stability. Specifically, the number average molecular weight of the viscosity index improver is, for example, 5,000 to 150,000, preferably 5,000 to 35,000 in the case of dispersed and non-dispersed polymethacrylates. In the case of isobutylene or a hydride thereof, 800 to 5,000, preferably 1,000 to 4,000, and in the case of an ethylene-α-olefin copolymer or a hydride thereof, 800 to 150,000, preferably The thing of 3,000-12,000 is preferable. Of these viscosity index improvers, when an ethylene-α-olefin copolymer or a hydride thereof is used, a lubricating oil composition having particularly excellent shear stability can be obtained. In the present invention, one or two or more compounds arbitrarily selected from these viscosity index improvers can be contained in any amount, but the content thereof is usually a lubricating oil composition. It is desirable that it is 0.1-40.0 mass% on an object basis.

  As the extreme pressure additive that can be used in combination with the lubricating oil composition of the present invention, any compound that is usually used as an extreme pressure additive for lubricating oils can be used, for example, disulfides, sulfurized olefins, sulfurized fats and oils. Sulfur compounds such as One kind or two or more kinds of compounds arbitrarily selected from these can be contained in any amount, but the content is usually 0.01 to 5. based on the total amount of the lubricating oil composition. It is preferably 0% by mass.

  The antioxidant that can be used in combination with the lubricating oil composition of the present invention can be used as long as it is generally used in lubricating oils, such as phenolic compounds and amine compounds. Alkylphenols such as 2,6-di-tert-butyl-4-methylphenol, bisphenols such as methylene-4,4-bisphenol (2,6-di-tert-butyl-4-methylphenol), phenyl- Naphtylamines such as α-naphthylamine, dialkyldiphenylamines, zinc dialkyldithiophosphates such as zinc bis (2-ethylhexyl) dithiophosphate, (3,5-di-tert-butyl-4-hydroxyphenyl) fatty acid (propionic acid, etc.) ) And mono- or polyhydric alcohols such as methanol, octadecanol, 1,6 hexadio , Neopentyl glycol, thiodiethylene glycol, triethylene glycol, esters of pentaerythritol and the like. One or two or more kinds of antioxidants arbitrarily selected from these can be contained in any amount, but the content is usually 0.01 to based on the total amount of the lubricating oil composition. It is desirable to be 5.0% by mass.

  As the corrosion inhibitor that can be used in combination with the lubricating oil composition of the present invention, any compound that is usually used as a corrosion inhibitor for lubricating oils can be used, for example, benzotriazole, tolyltriazole, thiadiazole, Examples include imidazole compounds. One or two or more compounds arbitrarily selected from these can be contained in any amount, but usually the content is 0.01 to 3. based on the total amount of the lubricating oil composition. It is preferably 0% by mass.

  As the antifoaming agent that can be used in combination with the lubricating oil composition of the present invention, any compound usually used as a defoaming agent for lubricating oil can be used, and examples thereof include silicones such as dimethyl silicone and fluorosilicone. It is done. One or two or more compounds arbitrarily selected from these can be contained in any amount, but the content is usually 0.001 to 0.00 on the basis of the total amount of the lubricating oil composition. It is desirable that it is 05 mass%.

  The colorant that can be used in combination with the lubricating oil composition of the present invention is arbitrary and can contain any amount, but the content is usually 0.001 to 1.% based on the total amount of the lubricating oil composition. It is preferably 0% by mass.

  Hereinafter, the content of the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these.

(Examples 1-6, Comparative Examples 1-9)
According to the composition shown in Table 1, lubricating oil compositions (Examples 1 to 6) according to the present invention were prepared. These compositions were subjected to the following intermetallic friction coefficient test and anti-shudder performance life test, and the evaluation results of intermetallic friction coefficient and anti-shudder performance life are shown in Table 1. For comparison, compositions (Comparative Examples 1 to 9) were prepared in accordance with the compositions shown in Table 2, the same tests were performed on these compositions, and the evaluation results are shown in Table 2.

[Shudder life test]
The “automatic transmission oil shudder prevention performance test method” defined in JASO M349-2001 was used as a reference, but the performance measurement was performed every 6 hours instead of the prescribed 24 hours. Based on the life of Comparative Example 3, the maintainability of the anti-shudder performance was evaluated based on the ratio.

[Friction coefficient test between metals]
Using an LFW-1 tester, the sample was slid for 60 minutes at an oil temperature of 80 ° C., a load of 445 N, and a sliding speed of 0.33 m / s. What averaged the friction coefficient between metals for 50 minutes to 60 minutes (at the time of a test completion) was made into the friction coefficient between samples of a sample.

The symbols in Table 1 and Table 2 represent the following.
(Base oil)
O-1: Hydrorefined mineral oil (100 ° C. kinematic viscosity: 4.2 mm ² / s, viscosity index: 127)
(Ester compound)
A-1: Propylene glycol-1-palmitate A-2: Ethylene glycol palmitate A-3: Propylene glycol-1-oleate A-4: Glycerol monooleate A-5: Alkylamine ethylene oxide adduct A-6 : Oleic acid A-7: Propylene glycol-1-laurate (phosphorus-containing antiwear agent)
B-1: tricresyl phosphate (P content: 8.4% by mass)
B-2: Tetraphenyl (m-phenylene) bisphosphate (P content: 10.7% by mass)
(Other additives)
Ashless dispersant: Boron-free succinimide (N content: 2.0 mass%, addition amount: 3.0 mass%)
Metal detergent: Overbased Ca sulfonate (Ca content: 11.4% by mass, base number: 300 mgKOH / g, addition amount: 0.5% by mass)
Extreme pressure agent: dibenzyl disulfide (added amount: 0.1% by mass)
Antioxidant: Hindered phenol (added amount: 0.5% by mass)
Metal deactivator: nitrogen-containing heterocyclic compound (addition amount: 0.05 mass%)
Viscosity index improver: PMA (Mw: 30,000, addition amount: 4.0% by mass)
Pour point depressant: PMA (Mw: 55,000, added amount: 0.3% by mass)
Antifoaming agent: polydimethylsiloxane (added amount: 0.002% by mass)

  As is apparent from the results of Tables 1 and 2, the lubricating oil compositions of Examples 1 to 6 according to the present invention all maintain a high transmission torque capacity, have excellent speed change characteristics, and have a long anti-sudder performance life. . In contrast, Comparative Example 1 containing no friction modifier has a high coefficient of friction between metals but does not have a life of anti-shudder performance. Moreover, the comparative example 2 which does not contain a phosphorus compound is inferior to the friction coefficient between metals. On the other hand, Comparative Examples 3 to 9 containing a friction modifier other than the component (A) according to the present invention are inferior in one or both of the intermetal friction coefficient and the life of anti-shudder performance.

  The lubricating oil composition of the present invention maintains anti-shudder performance even during long-term use, and has a high torque transmission capacity and good transmission characteristics of a wet clutch, and only for automatic transmissions and continuously variable transmissions. In addition, it can be suitably used as lubricating oil for construction machines, agricultural machines, manual transmissions, two-wheeled gasoline engines, four-wheeled gasoline engines, diesel engines, gas engines, shock absorbers, etc. having wet clutches and / or wet brakes. .

Claims (7)

A lubricant base oil containing (A) an ester compound represented by the following general formula (1) obtained by subjecting 1 equivalent of hydrocarbyldiol and 1 equivalent of carboxylic acid to a dehydration condensation reaction and (B) phosphorus A lubricating oil composition comprising an agent.

(In General Formula (1), any one of R ₁ and R ₂ is a hydrocarbyl group having 12 to 30 carbon atoms, the other is hydrogen or a hydrocarbyl group having 1 to 30 carbon atoms, and the carbon number of R ₃ Is 0-3.)
The lubricating oil composition according to claim 1, wherein R _{1 in the} general formula (1) is an alkyl group or an alkenyl group having 12 to 30 carbon atoms. The lubricating oil composition according to claim 1, wherein R _{2 in the} general formula (1) is hydrogen or a methyl group. The lubricating oil composition according to claim 1 or 2, wherein R _{3 in} the general formula (1) has 0 or 1 carbon atoms.   The lubricating oil composition according to claim 1, further comprising (C) a friction modifier and / or (D) one or more metal detergents.   The lubricating oil composition according to any one of claims 1 to 5, wherein the lubricating oil composition is used for a torque transmission device having a wet clutch and / or a wet brake.   The lubricating oil composition according to any one of claims 1 to 5, wherein the lubricating oil composition is used for an automatic transmission or a continuously variable transmission.