JP5409690B2 - Lubricating oil composition for transmission - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a lubricating oil composition for a transmission, and more particularly, an automatic transmission for an automobile, continuously variable, having excellent fatigue life and extreme pressure even with low viscosity, and does not deteriorate extreme pressure performance even after long-term use. The present invention relates to a lubricating oil composition for a transmission suitable for a transmission, a final reduction gear, and the like. Furthermore, the present invention relates to a method for improving fatigue life performance and extreme pressure performance of a low viscosity transmission lubricant.

  In recent years, there has been an urgent need to save energy in automobiles, construction machinery, agricultural machinery, etc., that is, to save fuel, in response to environmental issues such as reducing carbon dioxide emissions. Engines, transmissions, final reduction gears, compression Devices such as machines and hydraulic devices are strongly required to contribute to energy saving. Therefore, the lubricating oil used for these is required to reduce the stirring resistance and frictional resistance as compared with the conventional one.

  As one of the fuel saving means of the transmission and the final reduction gear, there is a reduction in viscosity of the lubricating oil. For example, among automatic transmissions, automotive automatic transmissions and continuously variable transmissions have torque converters, wet clutches, gear bearing mechanisms, oil pumps, hydraulic control mechanisms, etc., and final reduction gears have gear bearing mechanisms. By lowering the viscosity of the lubricating oil used in these, the agitation resistance and frictional resistance of torque converters, wet clutches, gear bearing mechanisms, oil pumps, etc. are reduced, and the power transmission efficiency is improved, thereby increasing the It is possible to improve the fuel efficiency of the vehicle.

  However, when the viscosity of the lubricating oil used in these is reduced, the fatigue life or extreme pressure properties are reduced, and seizure or the like may occur, causing problems in the transmission or the like. In particular, when a phosphorus-based extreme pressure agent is blended in order to improve the extreme pressure property of a low viscosity oil, the fatigue life is remarkably deteriorated, and it is generally difficult to reduce the viscosity. Viscosity index improvers can improve the viscosity characteristics of lubricating oils at low or practical temperatures, but are generally not expected to improve fatigue life and extreme pressure properties. When used, it is known to cause a decrease in viscosity due to shear over a long period of use.

As conventional transmission oils for automobiles, various performances such as transmission characteristics can be maintained for a long period of time. Synthetic oils and / or mineral oil base oils, antiwear agents, extreme pressure agents, metallic detergents, The thing which optimized and mix | blended the ash dispersant, the friction modifier, the viscosity index improver, etc. is disclosed (for example, refer patent documents 1-3).
However, none of these compositions are intended to improve fuel efficiency, so their kinematic viscosity is high, and the impact on fatigue life when reducing the viscosity of the lubricating oil and extreme pressure properties during initial and long-term use. Has not been studied at all, and thus compositions that can solve such problems have not been sufficiently studied so far.

JP-A-3-39399 JP 7-268375 A JP 2000-63869 A

  The present invention has been made in view of such circumstances, and the purpose of the present invention is to provide a transmission (manual transmission) having a long fatigue life even with a low viscosity and sufficient extreme pressure even after initial and long-term use. Excluding lubricating oil compositions suitable for automobile automatic transmissions, continuously variable transmissions, final reduction gears, etc., having both fuel saving performance and sufficient durability such as gears and bearings It is to provide.

  As a result of intensive studies to solve the above problems, the present inventors have found that a low-viscosity lubricating base oil, a polyester-based lubricating oil, a specific extreme pressure additive, and an alkaline earth metal-based high-viscosity synthetic lubricating oil The present inventors have found that a lubricating oil composition for a transmission containing a detergent can solve the above-mentioned problems and have completed the present invention.

That is, the present invention provides (A) a lubricating base oil composed of a mineral oil base oil having a kinematic viscosity at 100 ° C. of 1.5 to 10 mm ² / s, based on the total amount of the composition, (B) at 100 ° C. 7.5-20 mass% of 1 type (s) or 2 or more types chosen from polyester-type lubricating oil whose kinematic viscosity is 50-500 mm < ² > / s, (C) Phosphorus extreme pressure agent and / or phosphorus-sulfur extreme pressure agent Or 0.01 to 5% by mass of an extreme pressure additive containing a sulfur-based extreme pressure agent and 0.05 to 4.0% by mass of an alkaline earth metal detergent. The present invention relates to a lubricating oil composition for a transmission (excluding a manual transmission).

In the lubricating oil composition for a transmission according to the present invention, the (A) lubricating base oil is hydrocracked mineral oil having a kinematic viscosity at 100 ° C. of 1.5 to 3.8 mm ² / s based on the total amount of base oil. The base oil and / or wax isomerized isoparaffin base oil is preferably contained in an amount of 10% by mass or more.
In the lubricating oil composition for a transmission according to the present invention, the hydrocracking (A) of the lubricating base oil has a kinematic viscosity at 100 ° C. of 1.5 to 3.8 mm ² / s based on the total amount of the base oil. It is preferable to contain 70% by mass or more of mineral oil base oil and / or wax isomerized isoparaffin base oil.

  In the transmission lubricating oil composition of the present invention, it is preferable to blend a viscosity index improver having a weight average molecular weight of 50,000 or less.

  In the transmission lubricating oil composition of the present invention, as the extreme pressure additive (C), phosphorous acid, phosphorous acid monoesters, phosphorous acid diesters, phosphorous acid triesters, Phosphoric acid, thiophosphite monoesters, thiophosphite diesters, thiophosphite triesters, dithiophosphite, dithiophosphite monoesters, dithiophosphite diesters, dithiophosphite Triesters, trithiophosphorous acid, trithiophosphite monoesters, trithiophosphite diesters, trithiophosphite triesters, and at least one selected from these salts are included as essential, or Furthermore, sulfurized fats and oils, sulfurized olefins, dihydrocarbyl polysulfides, dithiocarbamates, thiadiazoles, and benzothiazoles It is preferable that by blending at least one selected et.

Further, the transmission lubricating oil composition of the present invention may further contain at least one additive selected from the group consisting of an ashless dispersant, an antioxidant, and a friction modifier. preferable.
Moreover, in the lubricating oil composition for transmissions of this invention, it is preferable that the kinematic viscosity in 100 degreeC of a composition is 3-8 mm < ² > / s.

Moreover, it is preferable that the lubricating oil composition for transmissions of this invention is used for a final reduction gear.
Moreover, it is preferable that the lubricating oil composition for transmission of this invention is used for an automatic speed gear.
Moreover, it is preferable that the lubricating oil composition for transmission of this invention is used for a continuously variable speed machine.

In addition, the present invention provides (A) a lubricating base oil composed of a mineral oil-based lubricating base oil having a kinematic viscosity at 100 ° C. of 1.5 to 10 mm ² / s, based on the total amount of the composition, (B) at 100 ° C. 7.5-20 mass% of 1 type (s) or 2 or more types chosen from polyester-type lubricating oil whose kinematic viscosity is 50-500 mm < ² > / s, (C) Phosphorus extreme pressure agent and / or phosphorus-sulfur extreme pressure agent Or 0.01 to 5% by mass of an extreme pressure additive containing a sulfur-based extreme pressure agent and 0.05 to 4.0% by mass of an alkaline earth metal detergent. The present invention relates to a method for improving fatigue life performance and extreme pressure performance of a lubricating oil composition (excluding manual transmissions).

Hereinafter, the lubricating oil composition for a transmission of the present invention will be described.
As the lubricating base oil of the component (A) in the present invention, a mineral lubricating base oil and / or a synthetic lubricating base oil having a kinematic viscosity at 100 ° C. of 1.5 to 10 mm ² / s is used.

  As a mineral oil base oil, a lubricating oil fraction obtained by subjecting crude oil to atmospheric distillation and vacuum distillation is subjected to solvent removal, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrorefining. In addition, paraffinic and naphthenic mineral oil base oils, normal paraffins, isoparaffins, and the like, which are refined by appropriately combining purification treatments such as sulfuric acid washing and clay treatment, and the like.

  There are no particular restrictions on the method for producing the mineral base oil, but for example, a lubricating oil fraction obtained by subjecting crude oil to atmospheric distillation and reduced pressure distillation can be subjected to solvent removal, solvent extraction, hydrocracking, solvent removal. Oils such as paraffinic and naphthenic oils that are refined by a single or a combination of two or more purification treatments such as wax, catalytic dewaxing, hydrorefining, sulfuric acid washing, and clay treatment can be used. These base oils may be used alone or in combination of two or more at any ratio.

Preferred mineral oil base oils include the following base oils.
[1] Distilled oil obtained by atmospheric distillation of paraffin-based crude oil and / or mixed-base crude oil;
[2] Vacuum distillation distillate (WVGO) of paraffin base crude oil and / or mixed base crude oil at atmospheric distillation residue;
[3] A wax obtained by a lubricant dewaxing step and / or a Fischer-Tropsch wax produced by a GTL process or the like;
[4] Mild hydrocracking treatment oil (MHC) of one or two or more mixed oils selected from [1] to [3];
[5] A mixed oil of two or more oils selected from [1] to [4];
[6] Degassed oil (DAO) of [1], [2], [3], [4] or [5];
[7] Mild hydrocracking treatment oil (MHC) of [6];
[8] A mixed oil of two or more kinds of oils selected from [1] to [7] is used as a feedstock oil, and this feedstock oil and / or a lubricating oil fraction recovered from this feedstock oil is used as a normal oil fraction. Lubricating oil obtained by refining by the refining method and collecting the lubricating oil fraction

  The normal refining method here is not particularly limited, and a refining method used in the production of the lubricating base oil can be arbitrarily employed. Examples of conventional purification methods include (a) hydrorefining such as hydrocracking and hydrofinishing, (b) solvent purification such as furfural solvent extraction, and (c) dewaxing such as solvent dewaxing and catalytic dewaxing. And (d) white clay refining with acid clay and activated clay, and (e) chemical (acid or alkali) purification such as sulfuric acid washing and caustic soda washing. In the present invention, one or more of these can be used in any combination and in any order.

As the mineral oil base oil used in the present invention, a base oil obtained by further subjecting the base oil selected from the above [1] to [8] to the following treatment is particularly preferable.
That is, the base oil selected from the above [1] to [8] is used as it is, or the lubricating oil fraction recovered from this base oil is hydrocracked or wax-isomerized, and the product is used as it is or from this. Collect the fraction, and then perform dewaxing treatment such as solvent dewaxing or contact dewaxing, and then solvent refining treatment, or after solvent refining treatment, dewaxing such as solvent dewaxing or contact dewaxing Hydrocracked mineral oil and / or wax isomerized isoparaffinic base oil produced by treatment is preferably used. The hydrocracked mineral oil and / or wax isomerized isoparaffin base oil is preferably used in an amount of 30% by mass or more, more preferably 50% by mass or more, and particularly preferably 70% by mass or more based on the total amount of the base oil.

  Examples of synthetic lubricating base oils include poly α-olefins or hydrides thereof, isobutene oligomers or hydrides thereof, isoparaffins, alkylbenzenes, alkylnaphthalenes, diesters (eg, ditridecylglutarate, di-2-ethylhexyl). Adipate, diisodecyl adipate, ditridecyl adipate, di-2-ethylhexyl sebacate, etc., polyol esters (eg, trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol 2-ethylhexanoate, pentaerythritol pelargonate, etc.) ), Polyoxyalkylene glycol, dialkyl diphenyl ether, polyphenyl ether and the like.

  Preferable synthetic lubricating base oils include poly α-olefins. The poly α-olefin is typically an α-olefin oligomer or co-oligomer having 2 to 32 carbon atoms, preferably 6 to 16 (eg, 1-octene oligomer, 1-decene oligomer, ethylene-propylene co-oligomer). And hydrides thereof.

  There are no particular restrictions on the method for producing the poly-α-olefin, but for example, aluminum trichloride, boron trifluoride or boron trifluoride and water, alcohol (eg, ethanol, propanol or butanol), carboxylic acid, or ester (eg, acetic acid) And polymerization of α-olefins in the presence of a polymerization catalyst such as a Friedel-Crafts catalyst containing a complex with ethyl or ethyl propionate).

  The (A) lubricating base oil of the present invention may be a mixture of two or more mineral base oils, or a mixture of two or more synthetic base oils. It can be a mixture with a base oil. And the mixing ratio of 2 or more types of base oil in the said mixture can be chosen arbitrarily.

(A) The upper limit of the kinematic viscosity at 100 ° C. of the lubricating base oil is 10 mm ² / s, preferably 8 mm ² / s, but when used for automatic transmissions and continuously variable transmissions, preferably 3. It is 8 mm ² / s, more preferably 3.6 mm ² / s. On the other hand, the lower limit of the kinematic viscosity at 100 ° C. of the (A) lubricating base oil is 1.5 mm ² / s, preferably 1.8 mm ² / s, particularly preferably 2.2 mm ² / s. By setting the kinematic viscosity at 100 ° C. to 10 mm ² / s or less, it becomes possible to obtain a lubricating oil composition having a smaller frictional resistance at a lubrication point because the fluid resistance becomes smaller. When used for a transmission, (A) the kinematic viscosity at 100 ° C. of the lubricating base oil is more preferably 3.8 mm ² / s or less, particularly preferably 3.6 mm ² / s or less. In particular, the effective concentration of the component (B) can be increased, and it is possible to further increase the fatigue life and the extreme pressure after initial and long-term use while having a low viscosity. In addition, by setting the kinematic viscosity at 100 ° C. to 1.5 mm ² / s or more, particularly 2.2 mm ² / s or more, oil film formation is sufficient, the lubricity is excellent, and the base oil under high temperature conditions It becomes possible to obtain a lubricating oil composition having a smaller evaporation loss.

  Further, these (A) lubricating base oils in the present invention are not particularly limited in their viscosity index, but the viscosity index is desirably 80 or more, preferably 90 or more, and particularly preferably 110 or more. By setting the viscosity index to 80 or more, it is possible to obtain a composition that is more excellent in fatigue life, extreme pressure after initial use and long-term use.

In addition, as (A) lubricating base oil in the present invention, when used for automatic transmissions and continuously variable transmissions, it is possible to further improve the fatigue life, initial pressure and extreme pressure after long-term use. In view of this, hydrocracked mineral oil and / or wax isomerized isoparaffin base oil having a kinematic viscosity at 100 ° C. of 1.5 to 3.8 mm ² / s, preferably 2.2 to 3.2 mm ² / s, is 10 Desirably, the hydrocracked mineral oil and / or wax isomerized isoparaffin base oil is desirably contained in an amount of at least mass%, preferably at least 30 mass%, more preferably at least 50 mass%, and even more preferably at least 70 mass%. Although it is most desirable that the lubricant base oil consisting of, optionally, a kinematic viscosity at 100 ° C. is 3.9~10mm ² / s, preferably 4 to 8 mm ² / s of mineral lubricating base oils及And / or synthetic lubricating base oil, preferably hydrocracked mineral oil, wax isomerized isoparaffinic base oil and poly α-olefin base oil, or one or more selected from (A) lubricating oil The kinematic viscosity at 100 ° C. of the base oil may be 1.5 to 4 mm ² / s.
Moreover, when it uses for (A) lube base oil for final reduction gears, the kinematic viscosity in 100 degreeC is 1.5-10 mm < ² > / s, Preferably it is 3.9-8 mm < ² > / s, Especially preferably, it is 5 It is preferable to use the above-described mineral oil and / or synthetic lubricant, particularly polyα-olefin and / or ester synthetic lubricant, which is ˜7 mm ² / s.

The component (B) in the lubricating oil composition for transmission of the present invention can be used without particular limitation as long as it is a polyester-based lubricating oil having a kinematic viscosity at 100 ° C. of 50 to 500 mm ² / s, and has an excellent fatigue life. , Extreme pressure after initial and long-term use can be imparted. The kinematic viscosity at 100 ° C. of the component (B) is preferably 50 to 450 mm ² / s, more preferably 80 to 400 mm ² / s, and still more preferably 90 to 350 mm ² / s. When the kinematic viscosity at 100 ° C. is less than 40 mm ² / s, the fatigue life and initial extreme pressure improvement effect are small, and when it exceeds 500 mm ² / s, the fatigue life improvement effect is hardly obtained, and it is used for a long time. Since it cannot maintain the extreme pressure later, it is not preferable respectively.

  The viscosity index of the component (B) in the present invention is not particularly limited, but is preferably 150 or more, more preferably 160 or more, preferably 400 or less, more preferably 280 or less, and particularly preferably 260 or less. The pour point of the component (B) is not particularly limited, but is preferably −10 ° C. or lower, more preferably −20 ° C. or lower, and −30 ° C. or lower in terms of not deteriorating the low temperature performance. It is particularly preferred that By using the component (B) having a viscosity index and a pour point in the above ranges, a composition having good viscosity characteristics from a low temperature to a high temperature can be obtained.

  The blending amount of the component (B) is 7.5 to 20% by mass, preferably 7.5 to 20% by mass based on the total amount of the composition in order to impart excellent fatigue life, extreme pressure after initial use and long-term use. 30% by mass. In order to further improve the excellent fatigue life, the extreme pressure property after initial use and long-term use, the blending amount of the component (B) is more preferably 10% by mass or more, and particularly preferably 20% by mass or less. . When the blending amount of component (B) is less than 7.5% by mass, the effect on fatigue life and initial extreme pressure is small, and when it exceeds 20% by mass, it becomes a high-viscosity lubricating oil, resulting in fuel saving performance. Since it cannot be expected, each is not preferable.

  In the present invention, the component (B) may be added as a mixture by adding other high-viscosity synthetic oil-based lubricating oil in addition to the polyester-based lubricating oil. And when using 2 or more types of other high-viscosity synthetic-oil type lubricating oil, the mixing ratio of these high-viscosity synthetic-oil type lubricating oil can be chosen arbitrarily.

As specific examples other than the component (B) in the present invention, a polyα-olefin having a kinematic viscosity at 100 ° C. of 50 to 500 mm ² / s or a hydride thereof, isoparaffin, alkylbenzene, alkylnaphthalene, polyester, poly Examples include oxyalkylene glycol, dialkyl diphenyl ether, and polyphenyl ether.

In the present invention, preferred examples other than the component (B) include poly α-olefin-based lubricating oils. Examples of poly α-olefins include isobutene oligomers, 1-octene oligomers, 1-decene oligomers, ethylene-propylene oligomers, etc., having 2 to 32 carbon atoms, preferably 2 to 16 carbon atoms, and particularly preferably α having 8 to 16 carbon atoms. -Polymers of olefins, copolymers thereof, or hydrides thereof.
The above oligomers are produced by oligomerization of 1-olefins in the presence of a metal oligomerization catalyst that is a supported metal with a low valence state. Preferred catalysts include low valence chromium on silica made by reduction of chromium using carbon monoxide as the reducing agent. The oligomerization is performed at a temperature selected according to the desired viscosity for the resulting oligomer (US Pat. Nos. 4,827,064, 4,870,073, etc.). Higher viscosity materials can be produced, where oligomerization temperatures below about 90 ° C. are used to produce higher molecular weight oligomers (US Pat. Nos. 5,012,020, 5,146,021, etc.).

Specifically, the polyester-based lubricating oil of component (B) in the present invention is a polyhydric alcohol having a neopentyl structure such as neopentyl glycol, trimethylolpropane, pentaerythritol, monocarboxylic acid and polycarboxylic acid, or the like. Examples thereof include complex esters obtained by adjusting the degree of polymerization so that the kinematic viscosity at 100 ° C. is 40 to 500 mm ² / s by esterifying or transesterifying monocarboxylic acid ester and polycarboxylic acid ester. . These may contain, for example, alkylene oxide or polyalkylene oxide in the molecule.

  Examples of the monocarboxylic acid include butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, elca Linear fatty acids such as acids, 2-ethylhexanoic acid, isooctylic acid, isononanoic acid, isocapriic acid, isolauric acid, isomyristic acid, isopalmitic acid, isostearic acid, isoarachidic acid, synthetic fatty acid by Koch method, synthetic alcohol by Gerve method Branched fatty acids such as fatty acids derived from these and mixtures thereof.

  Examples of the polycarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, dodecane-1,12-dicarboxylic acid, plasylic acid, dimer acid, and phthalic acid. Dibasic acids such as isophthalic acid and terephthalic acid, propylene-1,2,3-tricarboxylic acid, propane-1,2,3-tricarboxylic acid, 2-oxypropane-1,2,3-tricarboxylic acid, 4- Tribasic acids such as oxypentane-1,3,4-tricarboxylic acid, 2-oxyheptadecane-1,2,3-tricarboxylic acid, hemimellitic acid, trimellitic acid, trimesic acid, prenic acid, melophanoic acid, pyro A merit acid etc. and these mixtures are mentioned. Particularly preferred are dibasic acids such as adipic acid, azelaic acid, dodecane-1,12-dicarboxylic acid and dimer acid.

  Examples of the carboxylic acid ester and polycarboxylic acid ester include esters of the carboxylic acid or polycarboxylic acid with a lower alcohol (for example, methanol, ethanol, octanol, etc.).

  In addition, as a manufacturing method of the said complex ester, it reacts at 100-250 degreeC, for example, preferably 140-240 degreeC by the process of 1 step | paragraph or 2 steps | paragraphs or more, unreacted substance is distilled off, and catalyst is used. Examples of the method include removal, washing with water, and purification by dehydration by heating under reduced pressure. Here, toluene, benzene, xylene or the like may be used as an azeotropic dehydration solvent, or an inert gas such as nitrogen may be introduced for the purpose of removing reaction water, or the reaction may be performed under reduced pressure. As the catalyst, for example, an acidic catalyst such as sulfuric acid or paratoluenesulfonic acid, an alkaline catalyst such as potassium hydroxide, lithium hydroxide, or lithium acetate, or a metal oxide such as zinc oxide may be used.

Moreover, polyoxyalkylene glycol is mentioned as another preferable example other than (B) component in this invention. Examples of the polyoxyalkylene glycol include 3 to 10 carbon atoms such as propylene oxide, trimethylene oxide, butylene oxide, α-methyl-trimethylene oxide, 3,3′-dimethyl-trimethylene oxide, tetrahydrofuran, and dioxane. Is a polyoxypropylene glycol synthesized by ring-opening polymerization or ring-opening copolymerization of alkylene oxide having 3 to 5 carbon atoms so that the kinematic viscosity at 100 ° C. is 40 to 500 mm ² / s by selecting the degree of polymerization. A polyoxyalkylene glycol is mentioned.

The transmission lubricating oil composition of the present invention comprises a phosphorus-based extreme pressure agent and / or a sulfur-based extreme pressure agent, or an extreme pressure additive further containing a sulfur-based extreme pressure agent as the component (C). .
Examples of the phosphorous extreme pressure agent include phosphoric acid, phosphorous acid, phosphoric acid esters having 2 to 30 carbon atoms, preferably 3 to 20 carbon atoms, phosphorous acid esters, and salts thereof. It is done.
Examples of the phosphorus-sulfur extreme pressure agent include thiophosphoric acid, thiophosphorous acid, thiophosphoric acid esters having a hydrocarbon group having 2 to 30 carbon atoms, preferably 3 to 20 carbon atoms, thiophosphorous acid esters, and These salts, zinc dithiophosphate, and the like can be mentioned.
Examples of sulfur extreme pressure agents include sulfurized fats and oils, sulfurized olefins, dihydrocarbyl polysulfides, dithiocarbamates, thiadiazoles, and benzothiazoles.

  (C) As extreme pressure additives, phosphorous acid, phosphorous acid monoesters, phosphorous acid diesters, phosphorous acid triesters, thiophosphorous acid, thiophosphorous acid monoesters, thiophosphorous acid Acid diesters, thiophosphite triesters, dithiophosphite, dithiophosphite monoesters, dithiophosphite diesters, dithiophosphite triesters, trithiophosphite, trithiophosphite mono At least one selected from esters, trithiophosphite diesters, trithiophosphite triesters, and salts thereof is included as an essential component, or sulfurized fats and oils, sulfurized olefins, dihydrocarbyl polysulfides, It is preferable to add at least one selected from dithiocarbamates, thiadiazoles, and benzothiazoles. .

  Examples of the hydrocarbon group having 2 to 30 carbon atoms include an alkyl group, a cycloalkyl group, an alkylcycloalkyl group, an alkenyl group, an aryl group, an alkylaryl group, and an arylalkyl group.

Examples of the alkyl group include ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl And alkyl groups such as a group, a heptadecyl group, and an octadecyl group (these alkyl groups may be linear or branched).
As a cycloalkyl group, C5-C7 cycloalkyl groups, such as a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group, can be mentioned, for example.
Examples of the alkylcycloalkyl group include a methylcyclopentyl group, a dimethylcyclopentyl group, a methylethylcyclopentyl group, a diethylcyclopentyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, a methylethylcyclohexyl group, a diethylcyclohexyl group, a methylcycloheptyl group, a dimethylcyclopentyl group, and the like. Examples thereof include an alkylcycloalkyl group having 6 to 11 carbon atoms such as a heptyl group, a methylethylcycloheptyl group, and a diethylcycloheptyl group (the substitution position of the alkyl group with the cycloalkyl group is also arbitrary).

  Examples of alkenyl groups include butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecenyl, and An alkenyl group such as an octadecenyl group (these alkenyl groups may be linear or branched, and the position of the double bond is also optional).

As an aryl group, aryl groups, such as a phenyl group and a naphthyl group, can be mentioned, for example.
As the alkylaryl group, for example, tolyl group, xylyl group, ethylphenyl group, propylphenyl group, butylphenyl group, pentylphenyl group, hexylphenyl group, heptylphenyl group, octylphenyl group, nonylphenyl group, decylphenyl group, And an alkylaryl group having 7 to 18 carbon atoms such as undecylphenyl group and dodecylphenyl group (the alkyl group may be linear or branched, and the substitution position on the aryl group is arbitrary). it can.
Examples of the arylalkyl group include arylalkyl groups having 7 to 12 carbon atoms such as benzyl group, phenylethyl group, phenylpropyl group, phenylbutyl group, phenylpentyl group, and phenylhexyl group (these alkyl groups may be linear). It may be branched).

  Preferable examples of the phosphorous extreme pressure agent include monobutyl phosphate, monooctyl phosphate, monolauryl phosphate, dibutyl phosphate, dioctyl phosphate, dilauryl phosphate, tributyl phosphate, trioctyl phosphate, trilauryl phosphate, trilauryl phosphate. Phenyl phosphite; monobutyl phosphite, monooctyl phosphite, monolauryl phosphite, dibutyl phosphite, dioctyl phosphite, dilauryl phosphite, tributyl phosphite, trioctyl phosphite, trilauryl phosphite, triphenyl phosphite; Among them, phosphite ester extreme pressure agents, particularly phosphite triester extreme pressure agents are preferable.

  Further, preferred examples of the phosphorus-sulfur extreme pressure agent include, specifically, monobutylthiophosphate and monooctylthio having 1 to 3, preferably 2 or 3, particularly 3 sulfur atoms in the molecule. Phosphate, monolauryl thiophosphate, dibutyl thiophosphate, dioctyl thiophosphate, dilauryl thiophosphate, tributyl thiophosphate, trioctyl thiophosphate, triphenyl thiophosphate, trilauryl thiophosphate; monobutyl thiophosphate, monooctyl thiophosphate , Monolaurylthiophosphite, dibutylthiophosphite, dioctylthiophosphite, dilaurylthiophosphite, tributylthiophosphite, trioctylthiophosphite, triphenylthiophosphite , Trilauryl trithiophosphite; it includes and their salts. Among these thio phosphite extreme pressure, particularly preferably trithio phosphite-based extreme pressure agent.

  Examples of salts of (thio) phosphate esters and (thio) phosphite esters include (thio) phosphate monoester, (thio) phosphate diester, (thio) phosphorous acid monoester, ( Thio) A nitrogen compound such as an amine compound containing only ammonia, a hydrocarbon group having 1 to 8 carbon atoms, or a hydroxyl group-containing hydrocarbon group in the molecule is allowed to act on phosphorous acid diester, etc. The salt etc. which neutralized a part or all can be mentioned.

  Specific examples of the nitrogen compound include ammonia; monomethylamine, monoethylamine, monopropylamine, monobutylamine, monopentylamine, monohexylamine, monoheptylamine, monooctylamine, dimethylamine, methylethylamine, diethylamine, Alkylamines such as methylpropylamine, ethylpropylamine, dipropylamine, methylbutylamine, ethylbutylamine, propylbutylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, etc. Monomethanolamine, monoethanolamine, monopropanolamine, monobutanolamine, monopentanolamine, monohexanolamine, mono Butanolamine, monooctanolamine, monononanolamine, dimethanolamine, methanolethanolamine, diethanolamine, methanolpropanolamine, ethanolpropanolamine, dipropanolamine, methanolbutanolamine, ethanolbutanolamine, propanolbutanolamine, dibutanolamine, And alkanolamines such as dipentanolamine, dihexanolamine, diheptanolamine and dioctanolamine (the alkanol group may be linear or branched); and mixtures thereof.

Examples of sulfurized fats and oils include sulfurized lard, sulfurized rapeseed oil, sulfurized castor oil, sulfurized soybean oil, and sulfurized rice bran oil; disulfide fatty acids such as sulfurized oleic acid; and sulfurized esters such as methyl sulfide oleate. .
Examples of the sulfurized olefin include compounds represented by the following general formula (1).
R ¹¹ -S _x -R ¹² (1)
In the general formula (1), R ¹¹ represents an alkenyl group having 2 to 15 carbon atoms, R ¹² represents an alkyl group or alkenyl group having 2 to 15 carbon atoms, and x represents an integer of 1 to 8.
This compound can be obtained by reacting an olefin having 2 to 15 carbon atoms or a dimer or tetramer thereof with a sulfurizing agent such as sulfur or sulfur chloride. As the olefin, for example, propylene, isobutene, diisobutene and the like are preferably used.

Dihydrocarbyl polysulfide is a compound represented by the following general formula (2).
R ¹³ -S _y -R ¹⁴ (2)
In General Formula (2), R ¹³ and R ¹⁴ are each independently an alkyl group having 1 to 20 carbon atoms (including a cycloalkyl group), an aryl group having 6 to 20 carbon atoms, and an aryl having 7 to 20 carbon atoms. Represents an alkyl group, which may be the same or different from each other, and y represents an integer of 2 to 8;
Specific examples of R ¹³ and R ¹⁴ include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, and various pentyl groups. Groups, various hexyl groups, various heptyl groups, various octyl groups, various nonyl groups, various decyl groups, various dodecyl groups, cyclohexyl groups, phenyl groups, naphthyl groups, tolyl groups, xylyl groups, benzyl groups, and phenethyl groups. be able to.

  Specific examples of preferred dihydrocarbyl polysulfides include dibenzyl polysulfide, di-tert-nonyl polysulfide, didodecyl polysulfide, di-tert-butyl polysulfide, dioctyl polysulfide, diphenyl polysulfide, and dicyclohexyl polysulfide. It is done.

  Specific examples of dithiocarbamates include compounds represented by the following general formula (3) or (4).

In the general formulas (3) and (4), R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ , R ¹⁹ and R ²⁰ each independently represent a hydrocarbon group having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms. , R ²¹ represents a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, preferably a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, e represents an integer of 0 to 4, and f represents an integer of 0 to 6. .
Examples of the hydrocarbon group having 1 to 30 carbon atoms include an alkyl group, a cycloalkyl group, an alkylcycloalkyl group, an alkenyl group, an aryl group, an alkylaryl group, and an arylalkyl group.

  Examples of thiadiazoles include a 1,3,4-thiadiazole compound represented by the following general formula (5), a 1,2,4-thiadiazole compound represented by the general formula (6), and a general formula (7). Mention may be made of 1,4,5-thiadiazole compounds.

In the general formulas (5) to (7), R ²² , R ²³ , R ²⁴ , R ²⁵ , R ²⁶ and R ²⁷ may be the same or different, and each independently represents a hydrogen atom or 1 to 30 carbon atoms. And g, h, i, j, k, and l each independently represent an integer of 0 to 8.
Examples of the hydrocarbon group having 1 to 30 carbon atoms include an alkyl group, a cycloalkyl group, an alkylcycloalkyl group, an alkenyl group, an aryl group, an alkylaryl group, and an arylalkyl group.

In the present invention, as the component (C), a phosphorous acid triester extreme pressure agent such as triphenyl phosphite or a phosphorus-sulfur extreme pressure agent such as trilauryl trithiophosphite may be used. In addition, it is preferable in that it does not easily deteriorate the fatigue life, and it is possible to further improve the fatigue life by using any phosphorus extreme pressure agent and / or a phosphorus-sulfur extreme pressure agent and a sulfur extreme pressure agent in combination. Is preferable.
Moreover, these (C) components in this invention are 0.01-5 mass% from points, such as fatigue life, extreme pressure property, abrasion resistance, and oxidation stability, Preferably 0.1-0.1% is preferable. 2% by mass.

The lubricating oil composition for a transmission of the present invention is used as a viscosity index improver for the component (D) for the purpose of further improving fatigue life, extreme pressure after long-term use, wear resistance, or low-temperature fluidity. A non-dispersed viscosity index improver and / or a dispersed viscosity index improver having a weight average molecular weight of 50,000 or less, preferably 40,000 or less, and most preferably 10,000 to 35,000 can be blended. .
Specifically, as the non-dispersion type viscosity index improver, a homopolymer of a monomer (D-1) selected from compounds represented by the following formulas (8), (9) and (10) or Examples thereof include two or more kinds of monomers (D-1) or hydrides thereof. On the other hand, as the dispersion type viscosity index improver, specifically, two or more kinds of copolymers of monomers (D-2) selected from the compounds represented by the general formulas (11) and (12) or One or two or more of the monomers (D-1) selected from those obtained by introducing an oxygen-containing group into the hydride and compounds represented by the general formulas (8) to (10) and the general formula (11 ) And (12), a copolymer with one or more monomers (D-2) selected from the compounds represented by (12), or a hydride thereof.

In the above formula (8), R ¹ represents hydrogen or a methyl group, and R ² represents an alkyl group having 1 to 18 carbon atoms.
Specific examples of the alkyl group having 1 to 18 carbon atoms represented by R ² include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group. Examples thereof include a group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, and an octadecyl group (these alkyl groups may be linear or branched).

In the above formula (9), R ³ represents a hydrogen atom or a methyl group, and R ⁴ represents a hydrocarbon group having 1 to 12 carbon atoms.
Specific examples of the hydrocarbon group having 1 to 12 carbon atoms represented by R ⁴ include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, Alkyl groups such as decyl group, undecyl group, dodecyl group (these alkyl groups may be linear or branched); cycloalkyl groups having 5 to 7 carbon atoms such as cyclopentyl group, cyclohexyl group and cycloheptyl group; methyl Cyclopentyl group, dimethylcyclopentyl group, methylethylcyclopentyl group, diethylcyclopentyl group, methylcyclohexyl group, dimethylcyclohexyl group, methylethylcyclohexyl group, diethylcyclohexyl group, methylcycloheptyl group, dimethylcycloheptyl group, methylethylcycloheptyl group, diethyl Such as cycloheptyl group An alkylcycloalkyl group having 6 to 11 carbon atoms (the substitution position of these alkyl groups with the cycloalkyl group is arbitrary);
Alkenyl groups such as butenyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group, nonenyl group, decenyl group, undecenyl group, dodecenyl group, etc. (These alkenyl groups may be linear or branched, and position of double bond Is also optional);
Aryl group such as phenyl group, naphthyl group: alkylaryl group having 7 to 12 carbon atoms such as tolyl group, xylyl group, ethylphenyl group, propylphenyl group, butylphenyl group, pentylphenyl group, hexylphenyl group (these alkyl groups) May be linear or branched, and the position of substitution on the aryl group is also arbitrary); carbon number of benzyl, phenylethyl, phenylpropyl, phenylbutyl, phenylpentyl, phenylhexyl, etc. 7-12 arylalkyl groups (these alkyl groups may be linear or branched); and the like.

In the above formula (10), X ¹ and X ² are each independently a hydrogen atom, an alkoxy group having 1 to 18 carbon atoms (—OR ⁹ : R ⁹ is an alkyl group having 1 to 18 carbon atoms) or 1 carbon atom. to 18 monoalkylamino group ^{(-NHR 10: R} 10 is an alkyl group having 1 to 18 carbon atoms).

In the formula (11), R ⁵ represents a hydrogen atom or a methyl group, R ⁶ represents an alkylene group having 1 to 18 carbon atoms, Y ¹ represents ¹ to 2 nitrogen atoms, and 0 to 2 oxygen atoms. 1 represents an amine residue or heterocyclic residue, and m is 0 or 1.
Specific examples of the alkylene group having 1 to 18 carbon atoms represented by R ⁶ include an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a heptylene group, an octylene group, a nonylene group, a decylene group, Examples include an undecylene group, a dodecylene group, a tridecylene group, a tetradecylene group, a pentadecylene group, a hexadecylene group, a heptadecylene group, and an octadecylene group (these alkylene groups may be linear or branched).
Specific examples of the group represented by Y ¹ include dimethylamino group, diethylamino group, dipropylamino group, dibutylamino group, anilino group, toluidino group, xylidino group, acetylamino group, benzoylamino group, Examples thereof include a morpholino group, a pyrrolyl group, a pyrrolino group, a pyridyl group, a methylpyridyl group, a pyrrolidinyl group, a piperidinyl group, a quinonyl group, a pyrrolidonyl group, a pyrrolidono group, an imidazolino group, and a pyrazino group.

In the above formula (12), R ⁷ represents a hydrogen atom or a methyl group, and Y ² represents an amine residue or a heterocyclic residue containing 1 to 2 nitrogen atoms and 0 to 2 oxygen atoms.
Specific examples of the group represented by Y ² include a dimethylamino group, a diethylamino group, a dipropylamino group, a dibutylamino group, an anilino group, a toluidino group, a xylidino group, an acetylamino group, a benzoylamino group, and a morpholino group. Pyrrolyl group, pyrrolino group, pyridyl group, methylpyridyl group, pyrrolidinyl group, piperidinyl group, quinonyl group, pyrrolidonyl group, pyrrolidono group, imidazolino group, pyrazino group and the like.

Preferable examples of the monomer (D-1) are specifically alkyl acrylates having 1 to 18 carbon atoms, alkyl methacrylates having 1 to 18 carbon atoms, olefins having 2 to 20 carbon atoms, styrene, methylstyrene, and anhydrous maleic acid. Examples thereof include acid esters, maleic anhydride amides and mixtures thereof.
Preferable examples of the monomer (D-2) include dimethylaminomethyl methacrylate, diethylaminomethyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, 2-methyl-5-vinylpyridine, morpholinomethyl methacrylate, morpholinoethyl. Examples thereof include methacrylate, N-vinyl pyrrolidone and a mixture thereof.

  Copolymerization of a copolymer of one or more monomers selected from the (D-1) compound and one or more monomers selected from the (D-2) compound. The molar ratio is generally about monomer (D-1): monomer (D-2) = 80: 20 to 95: 5. The production method is arbitrary, but usually a copolymer is easily obtained by radical solution polymerization of monomer (D-1) and monomer (D-2) in the presence of a polymerization initiator such as benzoyl peroxide. It is done.

  Specific examples of the viscosity index improver that can be blended in the lubricating oil composition of the present invention include non-dispersed or dispersed polymethacrylates, non-dispersed or dispersed ethylene-α-olefin copolymers or hydrides thereof. , Polyisobutylene or a hydride thereof, styrene-diene hydrogenated copolymer, styrene-maleic anhydride ester copolymer, and polyalkylstyrene.

The viscosity index improver that can be blended in the lubricating oil composition of the present invention is preferably a polymethacrylate viscosity index improver because it is excellent in fatigue life, extreme pressure properties, wear resistance, and low temperature fluidity.
When the viscosity index improver is blended in the lubricating oil composition of the present invention, the blending amount is 0.1 to 10% by mass, preferably 0.5 to 5% by mass based on the total amount of the composition. When the blending amount of the viscosity index improver exceeds 10% by mass, it is not preferable because the initial extreme pressure property is difficult to maintain for a long time.

  The transmission lubricating oil composition of the present invention is further selected from the group consisting of (E) an ashless dispersant, (F) an alkaline earth metal detergent, (G) an antioxidant, and (H) a friction modifier. It is preferable to blend at least one additive.

(E) As an ashless dispersing agent, the following nitrogen compound can be mentioned, for example. These can be used alone or in combination of two or more.
(E-1) A succinimide having at least one alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule, or a derivative thereof (E-2) an alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule Or a derivative thereof (E-3) a polyamine having at least one alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule, or a derivative thereof

  More specifically, examples of the succinimide (E-1) include compounds represented by the following general formula (13) or (14).

In the general formula (13), R ³¹ represents an alkyl group or alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350 carbon atoms, and a represents an integer of 1 to 5, preferably 2 to 4.

In the general formula (14), R ³² and R ³³ individually represent an alkyl group or an alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350 carbon atoms, and b is 0 to 4, preferably 1 to 3. Indicates an integer.
In the succinimide, a so-called monotype succinimide represented by the general formula (13) in which succinic anhydride is added to one end of the polyamine is added by imidization, and succinic anhydride is added to both ends of the polyamine. The so-called bis-type succinimide represented by the general formula (14) in the form is included, and any of them or a mixture thereof can be used in the composition of the present invention.

  More specifically, examples of the benzylamine (E-2) include compounds represented by the following general formula (15).

In the general formula (15), R ³⁴ represents an alkyl group or alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350 carbon atoms, and c represents an integer of 1 to 5, preferably 2 to 4.
The benzylamine is obtained by reacting, for example, polyolefin (for example, propylene oligomer, polybutene, ethylene-α-olefin copolymer) with phenol to form alkylphenol, and then adding formaldehyde and polyamine (for example, diethylenetriamine, triethylenetetramine). , Tetraethylenepentamine, pentaethylenehexamine, etc.) can be obtained by reacting them by Mannich reaction.

More specifically, examples of the polyamine (E-3) include compounds represented by the following general formula (16).
^{_{R 35 -NH- (CH 2 CH 2}} NH) d -H (16)
In the general formula (16), R ³⁵ represents an alkyl group or alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350, and d represents an integer of 1 to 5, preferably 2 to 4.
The polyamine is, for example, chlorinated polyolefin (for example, propylene oligomer, polybutene, ethylene-α-olefin copolymer, etc.) and then ammonia or polyamine (for example, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepenta). Min, pentaethylenehexamine, etc.).

  Although the nitrogen content in the nitrogen compound is arbitrary, from the viewpoints of wear resistance, oxidation stability, friction characteristics, etc., the nitrogen content is usually preferably 0.01 to 10% by mass, more preferably. It is desirable to use 0.1 to 10% by mass.

  Examples of the derivative of the nitrogen compound include those having 2 to 30 carbon atoms such as monocarboxylic acid having 2 to 30 carbon atoms (fatty acid, etc.), oxalic acid, phthalic acid, trimellitic acid, and pyromellitic acid. A so-called acid-modified compound in which a part or all of the remaining amino group and / or imino group is neutralized or amidated by the action of polycarboxylic acid; A so-called boron-modified compound obtained by neutralizing or amidating a 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 compound; and an acid on the nitrogen compound And a modified compound in which two or more kinds of modifications selected from modification, boron modification, and sulfur modification are combined.

  When the ashless dispersant is blended in the composition of the present invention, the blending amount is not particularly limited, but it is preferably 0.5 to 10.0% by mass based on the total amount of the composition, and preferably 1 to 8.0. More preferably, it is mass%. When the content of the ashless dispersant is less than 0.5% by mass, the effect of improving fatigue life and extreme pressure is insufficient, and when it exceeds 10.0% by mass, the low-temperature fluidity of the composition is greatly increased. Since it deteriorates, it is not preferable respectively.

In the composition of the present invention, by blending the (F) alkaline earth metal detergent, the fatigue life is improved, and the initial extreme pressure property and the extreme pressure property after long-time use can be improved.
The alkaline earth metal detergent that can be blended in the composition of the present invention is preferably a basic metal detergent having a total base number of 20 to 450 mgKOH / g, preferably 50 to 400 mgKOH / g. The total base number is defined in JIS K2501, “Petroleum products and lubricating oils-Neutralization number test method”. It means the total base number measured by the perchloric acid method based on When the total base number of the alkaline earth metal detergent is less than 20 mgKOH / g, the effect of improving fatigue life and extreme pressure properties is insufficient, whereas when the total base number exceeds 450 mgKOH / g, it is structural. Are unstable, and the storage stability of the composition deteriorates.

  Specific examples of alkaline earth metal detergents having a total base number of 20 to 450 mgKOH / g include, for example, (F-1) alkaline earth metal sulfonate, (F-2) alkaline earth metal phenate, and (F-3). ) Alkaline earth metal salicylates can be mentioned, and one or more metal detergents selected from these can be used.

  (F-1) More specifically, the alkaline earth metal sulfonate is an alkali of an alkyl aromatic sulfonic acid obtained by sulfonating an alkyl aromatic compound having a molecular weight of 100 to 1500, preferably 200 to 700, for example. Mention may be made of earth metal salts. Particularly preferred are magnesium salts and / or calcium salts. Specific examples of the alkyl aromatic sulfonic acid include so-called petroleum sulfonic acid and synthetic sulfonic acid.

  As the petroleum sulfonic acid, those obtained by sulfonating an alkyl aromatic compound of a lubricating oil fraction of mineral oil or so-called mahoganic acid which is produced as a by-product when white oil is produced is used. As the synthetic sulfonic acid, for example, an alkylbenzene having a linear or branched alkyl group obtained as a by-product from an alkylbenzene production plant that is a raw material for detergents or by alkylating polyolefin with benzene is used as a raw material. , Sulfonated ones thereof, sulfonated ones of dinonylnaphthalene, and the like are used. Further, as the sulfonating agent for these alkyl aromatic compounds, for example, fuming sulfuric acid or sulfuric acid is used.

  (F-2) More specifically, the alkaline earth metal phenate is an alkylphenol having at least one linear or branched alkyl group having 4 to 30 carbon atoms, preferably 6 to 18 carbon atoms, and this alkylphenol. And alkylphenol sulfide obtained by reacting sulfur with sulfur or alkaline earth metal salt of Mannich reaction product of alkylphenol obtained by reacting alkylphenol with formaldehyde. Particularly preferred are magnesium salts and / or calcium salts.

  (F-3) More specifically, the alkaline earth metal salicylate is an alkali of alkyl salicylic acid having at least one linear or branched alkyl group having 4 to 30 carbon atoms, preferably 6 to 18 carbon atoms. Mention may be made of earth metal salts. Particularly preferred are magnesium salts and / or calcium salts.

  The alkaline earth metal sulfonate, alkaline earth metal phenate and alkaline earth metal salicylate have alkyl aromatic sulfonic acid, alkylphenol, alkylphenol sulfide, alkylphenol as long as the total base number is in the range of 20 to 450 mgKOH / g. The Mannich reaction product, alkylsalicylic acid, or the like directly reacts with an alkaline earth metal base such as an alkaline earth metal oxide or hydroxide of magnesium and / or calcium, or once such as sodium salt or potassium salt. Not only neutral salts (normal salts) obtained by replacing alkali metal salts with alkaline earth metal salts, but also neutral salts (normal salts) and excess alkaline earth metal salts or alkaline earths. Metal bases (alkali earth metal hydroxides and oxidations) ) In the presence of water, or an overbased salt obtained by reacting a neutral salt (normal salt) with an alkaline earth metal base in the presence of carbon dioxide ( Superbasic salts) are also included. These reactions are usually performed in a solvent (an aliphatic hydrocarbon solvent such as hexane, an aromatic hydrocarbon solvent such as xylene, a light lubricant base oil, or the like). In addition, metal detergents are usually marketed in a state diluted with a light lubricating base oil or the like, and are available, but generally the metal content is 1.0 to 20% by mass, It is desirable to use 2.0 to 16% by mass.

  In the composition of the present invention, when an alkaline earth metal detergent is blended, the blending amount is not particularly limited, but is usually preferably 0.05 to 4.0% by mass, more preferably based on the total amount of the composition. Is 0.1% by mass, 3.0% by mass or less, preferably 1% by mass or less, and particularly preferably 0.5% by mass or less. When the blending amount of the alkaline earth metal detergent is less than 0.05% by mass, the improvement in fatigue life and extreme pressure properties is insufficient, while when it exceeds 4.0% by mass, the oxidation stability of the composition is increased. , Which are not preferable.

(G) Any antioxidant that is generally used in lubricating oils, such as phenol compounds and amine compounds, can be used.
Specifically, alkylphenols such as 2-6-di-tert-butyl-4-methylphenol, and bisphenols such as methylene-4,4-bisphenol (2,6-di-tert-butyl-4-methylphenol). , Naphthylamines such as phenyl-α-naphthylamine, dialkyldiphenylamines, zinc dialkyldithiophosphates such as zinc di-2-ethylhexyldithiophosphate, (3,5-di-tert-butyl-4-hydroxyphenyl) fatty acid ( (Propionic acid etc.) or (3-methyl-5-tertbutyl-4-hydroxyphenyl) fatty acid (propionic acid etc.) and mono- or polyhydric alcohols such as methanol, octanol, octadecanol, 1,6 hexadiol, neo Pentyl glycol, thiodiethylene glycol, Triethylene glycol, esters of pentaerythritol and the like.
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.

  (H) As the friction modifier, any compound usually used as a friction modifier for lubricating oils can be used, but an alkyl group or alkenyl group having 6 to 30 carbon atoms, particularly a straight chain having 6 to 30 carbon atoms. An amine compound, an imide compound, a fatty acid ester, a fatty acid amide, a fatty acid metal salt or the like having at least one chain alkyl group or straight chain alkenyl group in the molecule is preferably used.

  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, or fatty acids thereof. An alkylene oxide adduct of a group amine can be exemplified. Examples of the imide compound include a succinimide having a linear or branched alkyl group or alkenyl group having 6 to 30 carbon atoms and / or a modified compound thereof using carboxylic acid, boric acid, phosphoric acid, sulfuric acid, or the like. . Examples of fatty acid esters include esters of linear or branched, preferably linear, fatty acids having 7 to 31 carbon atoms with aliphatic monohydric alcohols or aliphatic polyhydric alcohols. Examples of fatty acid amides include amides of linear or branched, preferably linear fatty acids having 7 to 31 carbon atoms, and aliphatic monoamines or aliphatic polyamines. 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.

  In the present invention, one kind or two or more kinds of compounds arbitrarily selected from the above friction modifiers can be contained in any amount, and the content thereof is usually 0.00 on the basis of the total amount of the composition. It is 01-5.0 mass%, Preferably it is 0.03-3.0 mass%.

  In the composition of the present invention, for the purpose of further improving its performance, if necessary, in addition to the above additives, further, a rust inhibitor, a corrosion inhibitor, a pour point depressant, a rubber swelling agent, an antifoaming agent, You may mix | blend various additives, such as a coloring agent, individually or in combination of several types.

  As the antifoaming agent, any compound usually used as an antifoaming agent for lubricating oil can be used, and examples thereof include silicones such as dimethyl silicone and fluorosilicone. One or two or more compounds arbitrarily selected from these can be blended in any amount, and the blending amount is usually 0.001 to 0.05% by mass based on the total amount of the composition. is there.

  As the colorant, any compound that is usually used can be used, and any amount can be blended. Usually, the blending amount is 0.001 to 1.0% by mass based on the total amount of the composition. is there.

The lubricating oil composition for a transmission according to the present invention can provide performance excellent in fatigue life, extreme pressure property after initial use and long-term use by being configured as described above. In order to further improve the performance for mechanical use, the kinematic viscosity at 100 ° C. of the composition is preferably 3 mm ² / s or more, more preferably 4 mm ² / s or more, and 5 mm ² / s or more. Is particularly preferred.
Further, in order to further improve the fuel saving performance as compared with these conventional transmission compositions, the kinematic viscosity at 100 ° C. of the composition is preferably 10 mm ² / s or less, more preferably 8 mm ² / s or less, and still more preferably. Is 7 mm ² / s or less, particularly preferably 6 mm ² / s or less.
Further, the kinematic viscosity at 40 ° C., preferably from 40 mm ² / s or less, more preferably 35 mm ² / s or less, particularly preferably not more than 30 mm ² / s, preferably 15 mm ² / s, more preferably 20 mm ² / s or more. By setting it as such a viscosity range, the fuel-saving performance can be provided compared with the conventional product, and the performance excellent in the fatigue life, the initial pressure, and the extreme pressure property after long-term use can be obtained.
When used for a final reduction gear, the composition has a kinematic viscosity, for example, a general SAE90 grade final reduction gear oil (100 ° C. kinematic viscosity: 18 mm ² / s, 40 ° C. kinematic viscosity: 190 mm). ² / s), the kinematic viscosity at 100 ° C. is preferably 16 mm ² / s, more preferably 15 mm ² / s or less, particularly preferably 14 mm ² / s or less, preferably It is desirable that the thickness is 7 mm ² / s or more, more preferably 9 mm ² / s or more, and particularly preferably 11 mm ² / s.
The kinematic viscosity at 40 ° C. is preferably 120 mm ² / s or less, more preferably 90 mm ² / s or less, still more preferably 85 mm ² / s or less, preferably 40 mm ² / s or more, more preferably 50 mm ² / s. It is desirable to set it above.

  The lubricating oil composition for a transmission according to the present invention is excellent in extreme pressure even after fatigue life and initial and long-term use even if the viscosity of the conventional product is lowered as described above, and can reduce the stirring resistance caused by the lubricating oil. For example, it can be used for automobile transmissions, automobile final reduction gears, particularly automatic transmissions, and continuously variable transmissions, thereby contributing to improvement in automobile fuel consumption.

  Hereinafter, the present invention will be described more specifically using examples and comparative examples, but the present invention is not limited to these examples.

(Example 1, Reference Examples 1-10 and Comparative Examples 1-6)
Various lubricating base oils and additives shown in Table 1 or Table 2 are blended, and the lubricating oil composition according to the present invention (Example 1 in Table 1), the lubricating oil composition for reference (reference in Table 1) Examples 1 to 10) and comparative lubricating oil compositions (Comparative Examples 5 to 6 in Table 1 and Comparative Examples 1 to 4 in Table 2) were prepared. The amount of each additive added is based on the total amount of the composition.
About each obtained composition, the fatigue life was evaluated by the fatigue life test shown to the following (1). Moreover, the extreme pressure property after initial and long-term use was evaluated by the extreme pressure property test shown in the following (2). Note that new oil was used for initial extreme pressure evaluation, and deteriorated oil previously deteriorated by the ultrasonic shear test shown in (3) was used for extreme pressure evaluation after long-term use. The results of the performance evaluation are shown in Table 1 and Table 2, respectively.

(1) Fatigue life test Using a rolling fatigue tester as a tester, the fatigue life was measured as follows.
(bearing)
Material: Bearing steel Test piece: φ60 x 5mm thickness
Test steel ball dimensions: φ3 / 8 inch (test conditions)
Rotation speed: 1800rpm
Oil temperature: 150 ° C
Surface pressure: 6.4 GPa
(Judgment criteria)
The time until flaking occurred on the test piece was defined as the fatigue life, and L50 was calculated from the result of the test of N = 6.

(2) Extreme Pressure Test The extreme pressure test was conducted with a shell four-ball tester in accordance with ASTM D 2783 “Lubricant Load Capacity Test Method”. In this test, a total of four test steel balls are fixed to the sample container and the rotating shaft, and the sample is filled into the sample container. A load is applied while the rotating shaft is stationary, and it is rotated for 10 seconds at a speed of 1760 ± 40 rotations per minute. The maximum non-seizure load was obtained by increasing the load. The maximum non-seizure load is obtained at the maximum test load at which the measured wear scar diameter does not exceed 105% of the compensated wear scar diameter at the test load at that time. The greater the maximum non-seizure load, the better the extreme pressure property.

(3) Ultrasonic shear test In accordance with the automatic transmission oil shear stability test method defined in JASO M347-95, a shear test for 8 hours was performed. This test evaluates the degree of decrease in kinematic viscosity in the process of using automatic transmission oil. The 8-hour shear test is equivalent to 100,000 km or more of actual running, and the oil after the test runs 100,000 km It is thought to correspond to later oil.

As is clear from the results shown in Tables 1 and 2, the lubricating oil composition of the present invention (Example 1) has a long fatigue life, similar to the lubricating oil composition for reference (Reference Examples 1 to 10). It shows high extreme pressure even after initial and long-term use.
In addition, when the viscosity of the lubricating base oil of the component (A) is 2.6 mm ² / s (100 ° C.) (Example 1 and Reference Examples 1 to 2), in particular, the kinematic viscosity of the component (B) is 50 to 50 When a poly α-olefin-based lubricating oil of 500 mm ² / s is used (Reference Examples 1 and 2), the fatigue life and the extreme pressure performance after the initial and long-term use can be further improved.
When the hydrocracked mineral oil or the poly α-olefin base oil is used as the lubricating oil (Reference Example 4, Comparative Example 6), a solvent refined mineral oil is used, and the component (B) is used in a predetermined amount or less. Compared to the case (Comparative Example 5), the fatigue life can be made longer. Further, a phosphite extreme pressure agent (Reference Example 2), particularly a phosphite triester extreme pressure agent (Reference Example 5) or a thiophosphite extreme pressure agent (Reference Example 7) was used. In addition, in the case where a phosphorus extreme pressure agent and a sulfur extreme pressure agent are used in combination (Reference Examples 8 to 10), the fatigue life is longer than when a phosphate ester extreme pressure agent (Reference Example 6) is used. Can be longer.
On the other hand, when the component (B) is not blended (Comparative Example 1), when the poly α-olefin-based lubricating oil having a kinematic viscosity at 100 ° C. exceeding 500 mm ² / s is used (Comparative Examples 2 and 3), Not only the fatigue life performance is remarkably inferior, but the extreme pressure performance after long-term use deteriorates. When a viscosity index improver having a weight average molecular weight of 100,000 or more is blended in place of the component (B), improvement in fatigue life and maintenance of extreme pressure performance after long-term use cannot be expected. Further, when the component (C) is not blended (Comparative Example 4), the initial extreme pressure performance is remarkably inferior.

In the transmission oil composition of the present invention, the stirring resistance of the gear, the transmission clutch, the torque converter, and the oil pump can be reduced by having the above-described configuration, and a contribution to improving fuel consumption in the transmission and the final reduction gear can be expected. not, in which can be the fatigue life formic composition excellent in extreme pressure properties, such as Young bearings. Therefore, the lubricating oil composition of the present invention is extremely effective as an unconventional fuel-saving transmission lubricating oil composition.

Claims (11)

(A) To a lubricant base oil composed of a mineral oil base oil having a kinematic viscosity at 100 ° C. of 1.5 to 10 mm ² / s, based on the total amount of the composition, (B) a polyhydric alcohol having a neopentyl structure; A polyester system comprising a complex ester having a kinematic viscosity at 100 ° C. of 50 to 500 mm ² / s obtained by esterification or transesterification of monocarboxylic acid and polycarboxylic acid, or monocarboxylic acid ester and polycarboxylic acid ester 7.5 to 20% by mass of one or more selected from lubricating oil, (C) an extreme pressure containing a phosphorus extreme pressure agent and / or a phosphorus-sulfur extreme pressure agent, or a sulfur extreme pressure agent A transmission comprising 0.01 to 5% by mass of an additive and 0.05 to 4.0% by mass of (F) an alkaline earth metal detergent. Excluding dynamic transmission) for lubricating oil compositions. The (A) lubricating base oil is a hydrocracked mineral oil base oil and / or wax isomerized isoparaffin base oil having a kinematic viscosity at 100 ° C. of 1.5 to 3.8 mm ² / s based on the total amount of base oil. The lubricating oil composition for a transmission according to claim 1, comprising 10% by mass or more. The (A) lubricating base oil is a hydrocracked mineral oil base oil and / or wax isomerized isoparaffin base oil having a kinematic viscosity at 100 ° C. of 1.5 to 3.8 mm ² / s based on the total amount of base oil. The lubricating oil composition for a transmission according to claim 1, comprising:   The lubricating oil composition for a transmission according to any one of claims 1 to 3, comprising a (D) viscosity index improver having a weight average molecular weight of 50,000 or less.   Examples of the extreme pressure additive (C) include phosphorous acid, phosphorous acid monoesters, phosphorous acid diesters, phosphorous acid triesters, thiophosphorous acid, thiophosphorous acid monoesters, thiophosphorous acid Acid diesters, thiophosphite triesters, dithiophosphite, dithiophosphite monoesters, dithiophosphite diesters, dithiophosphite triesters, trithiophosphite, trithiophosphite mono At least one selected from esters, trithiophosphite diesters, trithiophosphite triesters, and salts thereof is blended as an essential component, or sulfurized fats and oils, sulfurized olefins, dihydrocarbyl polysulfides And at least one selected from dithiocarbamates, thiadiazoles, and benzothiazoles. The lubricating oil composition according to any one of claims 1 to 4, characterized in.   6. The composition according to claim 1, comprising at least one selected from the group consisting of (E) an ashless dispersant, (G) an antioxidant, and (H) a friction modifier. The lubricating oil composition for a transmission according to Item. The lubricating oil composition for a transmission according to any one of claims 1 to 6, wherein the composition has a kinematic viscosity at 100 ° C of 3 to 8 mm ² / s.   The lubricating oil composition for a transmission according to any one of claims 1 to 7, which is used in a final reduction gear.   The lubricating oil composition for a transmission according to any one of claims 1 to 7, which is used in an automatic transmission.   The lubricating oil composition for a transmission according to any one of claims 1 to 7, which is used for a continuously variable transmission. (A) To a lubricant base oil composed of a mineral oil base oil having a kinematic viscosity at 100 ° C. of 1.5 to 10 mm ² / s, based on the total amount of the composition, (B) a polyhydric alcohol having a neopentyl structure; A polyester system comprising a complex ester having a kinematic viscosity at 100 ° C. of 50 to 500 mm ² / s obtained by esterification or transesterification of monocarboxylic acid and polycarboxylic acid, or monocarboxylic acid ester and polycarboxylic acid ester 7.5 to 20% by mass of one or more selected from lubricating oils and (C) a phosphorus-based extreme pressure agent and / or a phosphorus-sulfur extreme pressure agent, or further a sulfur-based extreme pressure agent A transmission comprising 0.01 to 5% by mass of an additive and 0.05 to 4.0% by mass of (F) an alkaline earth metal detergent. Fatigue life performance and extreme pressure performance improving method of the transmission excluding) for lubricating oil compositions.