JP2014172947A - Friction modifier and lubricating-oil composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compound that, when included in a lubricating oil, can enhance longevity of shudder prevention, as well as gear-shift characteristics and torque transmission capacity, all to satisfactory levels.SOLUTION: The invention provides a dicarboxylic acid ester compound represented by the specified general formula (1). [In the formula (1), Rto Reach independently represent hydrogen or a C1-30 hydrocarbyl group and can be identical or different, where at least one of Rto Ris a C8-30 hydrocarbyl group; Ris a single bond or a C1-30 hydrocarbylene group; m and n are each independently an integer between 1 and 4; and x and y are each independently an integer between 1 and 3.]

Description

  The present invention relates to a novel compound exhibiting friction adjusting ability, a friction adjusting agent, and a lubricating oil composition having excellent friction characteristics.

  Many automatic transmissions and continuously variable transmissions have a torque converter, and engine torque is transmitted to the transmission via lubricating oil. The torque converter is structurally unable to transmit power unless there is a differential rotation between the input side (engine side) and the output side (transmission side), and this differential rotation causes the power transmission efficiency of the transmission to decrease. It has become. In recent years, there has been an increasing demand for saving fuel in automobiles, and transmissions are also required to have improved power transmission efficiency than ever before. As a means of improving power transmission efficiency in a transmission having a torque converter, a lock-up clutch is built into the torque converter, and in addition to power transmission via lubricating oil, engine torque is directly shifted according to driving conditions. Many techniques for transmitting to the mechanism have been adopted in recent years.

  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, there is a transmission loss of the torque converter in the low speed range such as when starting, so there is still room for improvement in terms of overall fuel consumption.

  In order to reduce this transmission loss, a slip control (slip control) method is recently 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 slip control of the clutch is performed, an abnormal vibration (shudder) due to a slip stick phenomenon occurs on the friction surface of the lockup clutch, and the ride quality of the automobile may be impaired. In order to prevent the occurrence of shudder, it is extremely important to adjust the μ-V characteristic so that the friction coefficient (μ) increases as the sliding speed (V) increases in the lockup clutch. V-characteristic adjustment capability (shudder prevention performance) is assigned to lubricating oil (transmission oil) (see, for example, Patent Document 1). Since the anti-shudder performance of the lubricating oil decreases as the lubricating oil deteriorates, there is a demand for a lubricating oil that has excellent ability to maintain the anti-shudder performance (shudder prevention life). In pursuit of improved fuel efficiency, the low speed range in which slip control is performed is increasingly advanced, and further improvement in the anti-shudder life is desired.

  Further, the automatic transmission and the continuously variable transmission have a wet transmission clutch in the transmission mechanism and the forward / reverse switching mechanism. When the friction characteristics of the speed change clutch are poor, for example, when the difference between the dynamic friction coefficient and the static friction coefficient is too large, a shock is generated at the time of speed change and the riding comfort of the automobile is impaired. Therefore, it is required that the lubricating oil used in these transmissions be given good shift characteristics to the shift clutch in order to reduce shock when the shift clutch is engaged.

  Giving the lubricating oil anti-shudder performance and improving the friction characteristics of the transmission clutch are generally performed by blending a friction modifier with the lubricating oil. Therefore, in order to improve the anti-shudder life and the speed change characteristics of the lubricating oil, it can be considered as one means to add a large amount of a friction modifier. However, depending on the type of friction modifier to be blended, the friction coefficient (for example, the friction coefficient between metals in a continuously variable transmission, etc.) may be significantly reduced, and this time the transmission torque capacity in the transmission cannot be secured sufficiently. Occurs. Thus, in the approach by blending the friction modifier with the lubricating oil, the shudder prevention life, the speed change characteristic, and the transmission torque capacity are generally in a trade-off relationship.

JP 2004-155924 A

  Accordingly, an object of the present invention is to provide a compound that can increase both the anti-shudder life, the speed change characteristic, and the transmission torque capacity to a satisfactory level when contained in a lubricating oil. Also provided are a friction modifier containing the compound and a lubricating oil composition containing the friction modifier.

  The first aspect of the present invention is a dicarboxylic acid ester compound represented by the following general formula (1).

［式（１）中、Ｒ^１〜Ｒ^４はそれぞれ独立に水素または炭素数１〜３０のヒドロカルビル基を表し、Ｒ^１〜Ｒ^４は同一でも異なっていてもよく、Ｒ^１〜Ｒ^４のうちの少なくとも１つは炭素数８〜３０のヒドロカルビル基であり；Ｒ^５は単結合又は炭素数１〜３０のヒドロカルビレン基を表し；ｍ及びｎはそれぞれ独立に１〜４の整数であり；ｘ及びｙはそれぞれ独立に１〜３の整数である。］

[In the formula (1), R ^{1 to} R ⁴ each independently represent hydrogen or a hydrocarbyl group having 1 to 30 carbon atoms, and R ^{1 to} R ⁴ may be the same or different, and R ^{1 to} R ⁴ At least one is a hydrocarbyl group having 8 to 30 carbon atoms; R ⁵ represents a single bond or a hydrocarbylene group having 1 to 30 carbon atoms; m and n are each independently an integer of 1 to 4; x and y are each independently an integer of 1 to 3. ]

In the first aspect of the present invention, it is preferable that at least one of R ¹ and R ² and at least one of R ³ and R ⁴ is a hydrocarbyl group having 1 to 30 carbon atoms.

  The second aspect of the present invention is a friction modifier containing the dicarboxylic acid ester compound according to the first aspect of the present invention.

  A third aspect of the present invention is a lubricating oil composition containing a lubricating base oil and the friction modifier according to the second aspect of the present invention. The lubricating oil composition of the present invention can be particularly preferably used as a continuously variable transmission oil.

  According to the dicarboxylic acid ester compound of the present invention, the inclusion of the dicarboxylic acid ester compound in the lubricating oil makes it possible to increase both the anti-shudder life, the speed change characteristic and the friction coefficient (transmission torque capacity) of the lubricating oil to a satisfactory level. Therefore, it can be preferably contained as a friction modifier in the lubricating oil composition.

  The lubricating oil composition containing the friction modifier of the present invention has an improved anti-sudder life and good speed change characteristics, and can also improve the transmission torque capacity due to the increased coefficient of friction between metals. . Therefore, it can be preferably used as an automatic transmission oil or a continuously variable transmission oil.

  Hereinafter, the present invention will be described in detail. Unless otherwise specified, the notation “A to B” in the numerical range means “A or more and B or less”. In this notation, when a unit is attached to only the numerical value B, the unit is also applied to the numerical value A.

<1. Dicarboxylic acid ester compound>
(Construction)
The dicarboxylic acid ester compound according to the first aspect of the present invention will be described. The dicarboxylic acid ester compound of the present invention has a structure represented by the following general formula (1).

In the general formula (1), R ^{1 to} R ⁴ each independently represent hydrogen or a hydrocarbyl group having 1 to 30 carbon atoms, and R ^{1 to} R ⁴ may be the same or different, and R ^{1 to} R ⁴ At least one of them is a hydrocarbyl group having 8 to 30 carbon atoms. R ⁵ represents a single bond or a hydrocarbylene group having 1 to 30 carbon atoms. M and n are each independently an integer of 1 to 4, and x and y are each independently an integer of 1 to 3.

Here, specific examples of the hydrocarbyl group having 1 to 30 carbon atoms that can be employed as R ^{1 to} R ⁴ include an alkyl group (which may have a ring structure) and an alkenyl group (position of a double bond). Are arbitrary and may have a ring structure.), Aryl groups, alkylaryl groups, alkenylaryl groups, arylalkyl groups, arylalkenyl groups, and the like.

  Examples of the alkyl group include various linear or branched alkyl groups. Examples of the alkyl group having a ring structure include a cycloalkyl group and an alkylcycloalkyl group. Examples of the cycloalkyl group include cycloalkyl groups having 5 to 7 carbon atoms such as a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group. In the alkylcycloalkyl group, the substitution position of the alkyl group to the cycloalkyl group is arbitrary.

  Examples of the alkenyl group include linear or branched alkenyl groups. Examples of the alkenyl group having a ring structure include a cycloalkenyl group, an alkylcycloalkenyl group, and an alkenylcycloalkyl group. The cycloalkyl group in the alkenylcycloalkyl group is the same as described above. Examples of the cycloalkenyl group include cycloalkyl groups having 5 to 7 carbon atoms, such as a cyclopentenyl group, a cyclohexenyl group, and a cycloheptenyl group. The substitution position of the alkyl group to the cycloalkenyl group in the alkylcycloalkenyl group and the substitution position of the alkenyl group to the cycloalkyl group in the alkenylcycloalkyl group are arbitrary.

  Examples of the aryl group include a phenyl group and a naphthyl group. In the alkylaryl group, alkenylaryl group, arylalkyl group, and arylalkenyl group, the substitution position of the alkyl group or alkenyl group to the aryl group is arbitrary.

R ⁵ is a single bond or a hydrocarbylene group having 1 to 30 carbon atoms. Specific examples of the hydrocarbylene group that can be used as R ⁵ in the present invention include an alkylene group (which may have a ring structure) and an alkenylene group (the position of the double bond is arbitrary, and the ring structure). And an arylene group, an alkylarylene group, an alkenylarylene group, an arylalkylene group, an arylalkenylene group, and the like.

  Examples of the alkylene group include various linear or branched alkylene groups. Examples of the alkylene group having a ring structure include a cycloalkylene group and an alkylcycloalkylene group. Examples of the cycloalkylene group include a cycloalkylene group having 5 to 7 carbon atoms such as a cyclopentylene group, a cyclohexylene group, and a cycloheptylene group. The substitution positions of the two oxycarbonyl groups on the cycloalkylene group are arbitrary. In the alkylcycloalkylene group, the substitution position of the alkyl group on the cycloalkylene group is arbitrary.

  Examples of the alkenylene group include various linear or branched alkenylene groups. Examples of the alkenylene group having a ring structure include a cycloalkenylene group, an alkylcycloalkenylene group, and an alkenylcycloalkylene group. The cycloalkylene group in the alkenyl cycloalkylene group is the same as described above. Examples of the cycloalkenylene group include a cycloalkylene group having 5 to 7 carbon atoms such as a cyclopentenylene group, a cyclohexenylene group, and a cycloheptenylene group. The substitution positions of the two oxycarbonyl groups on the cycloalkenylene group are arbitrary, and the same applies to the cycloalkylene group. Moreover, the substitution position of the alkyl group to the cycloalkenylene group in the alkylcycloalkenylene group and the substitution position of the alkenyl group to the cycloalkylene group in the alkenylcycloalkylene group are arbitrary.

  Examples of the arylene group include a phenylene group and a naphthylene group. In the alkylarylene group, alkenylarylene group, arylalkylene group, and arylalkenylene group, the substitution position of the alkyl group or alkenyl group to the arylene group and the substitution position of the arylene group to the alkylene group or alkenylene group are arbitrary. .

In the general formula (1), it is preferable that at least one of R ¹ and R ² and at least one of R ³ and R ⁴ are each a hydrocarbyl group having 1 to 30 carbon atoms. By adopting such a substituted form of the amino group, it is possible to increase the resistance to deactivation of the amino group, and thus further increase the anti-shudder life. In the present invention, in the general formula (1), it is necessary that at least one of R ^{1 to} R ⁴ is a hydrocarbyl group having 8 to 30 carbon atoms, and at least one of R ¹ and R ² , And at least one of R ³ and R ⁴ is preferably a hydrocarbyl group having 8 to 30 carbon atoms, more preferably 10 or more, still more preferably 12 or more, and even more preferably 20 or less. It is.

For each of R ^{1 to} R ⁴ , when it is a hydrocarbyl group, a saturated hydrocarbyl group (having a ring structure) is used from the viewpoints of stability and adjustment of the amino group adsorption force within a suitable range. It is preferable that the saturated hydrocarbyl group has a chain portion. The chain portion may be linear or branched. However, it is particularly preferable that the longest carbon chain has 8 or more carbon atoms (for example, a 4- (2-ethyldecyl) cyclohexyl group has) from the root (the root closest to the nitrogen atom) contained in the chain portion. The carbon number of the longest carbon chain from the root included in the chain portion is 10, and the carbon of the longest carbon chain from the root included in the chain portion of the 4- (9-cyclopentyldecan-3-yl) cyclohexyl group The number is 8.)

Regarding R ⁵ , the minimum number of carbons connecting two oxycarbonyl groups on R ⁵ is preferably 1 or more, preferably 6 or less, and more preferably 4 or less. Here, the "minimum number of carbon atoms connecting the two oxycarbonyl group on R ^5" is an integer uniquely defined for R ^5, for example, when R ⁵ is a single bond is 0, substituted or In the case of an unsubstituted α, ω-chain alkylene group or chain alkenylene group, it means the carbon number of the main chain (for example, 6 in the case of a 2-decylhexane-1,6-diyl group). For example, when R ⁵ is a cyclohexane-1,2-diyl group, it is 2, and when R ⁵ is a cyclohexane-1,3-diyl group, it is 3, and a cyclohexane-1,4-diyl group is In some cases, it is 4, for example, when R ⁵ is a naphthalene-1,8-diyl group, it is 3, and when it is a naphthalene-1,7-diyl group, it is 4, and naphthalene-1 , 6-diyl group, 5 There, when a naphthalene-2,6-diyl group is a 6.

When R ⁵ is a hydrocarbylene group, R ⁵ may be saturated or unsaturated. However, from the viewpoint of stability, a saturated hydrocarbylene group (an alkylene group which may have a ring structure) is preferable.
Moreover, in said general formula (1), m and n become like this. Preferably it is 1-3, More preferably, it is 1-2. X and y are preferably 1-2.

(Production of dicarboxylic acid ester compound)
The method for producing the dicarboxylic acid ester compound of the present invention is not particularly limited. For example, it can be manufactured as follows. In the following, in order to simplify the explanation, the description will be made mainly assuming that m = n, x = y, R ¹ = R ³ , and R ² = R ⁴ , but the dicarboxylic acid ester compound of the present invention Is not limited to this embodiment.

  For convenience of explanation below, the production of the carboxylic acid compound of the above formula (1) is divided into a case where (b) x (= y) is 1 and a case where (b) x (y) is 2 to 3. I will explain.

(Manufacturing (I): When x (= y) is 1)
When x (= y) is 1, the dicarboxylic acid ester compound of the above formula (1) is represented by the following formula (2).

The dicarboxylic acid ester compound of the above formula (2) can be produced, for example, as follows. That is, starting from an ω-alkenol in which the hydroxy group is protected with a silyl protecting group such as tert-butyldimethylsilyl (TBS) group protection, dimethyldioxirane (DMDO: acetone and 2KHSO ₅ · KHSO ₄ · K ₂ SO ₄ (Prepared from Oxone (registered trademark)) and the like to epoxidize the C═C double bond (the following formula (3)), and ring-open the epoxide by nucleophilic attack of the amine (the following formula (4)), protecting the epoxide-derived hydroxy group with another protecting group (for example, a benzyl protecting group such as a benzyl (Bn) protecting group or a p-methoxybenzyl (PMB) protecting group) (the following formula (5) ), Deprotecting the terminal hydroxy group (for example, in the case of a silyl protecting group such as TBS, tetrabutylammonium fluoride (TBAF) treatment or HF-pyridine). Management, and the like.) By, preparing alcohol as a synthetic intermediate (formula (6)). Then, the protected alcohol is condensed with dicarboxylic acid HO ₂ C—R ⁵ —CO ₂ H (the following formula (7)) to deprotect the epoxide-derived hydroxy group (for example, 2 in the case of a PMB protecting group). It can be produced by a 3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) treatment or catalytic reduction (H ₂ / Pd) or the like; the following formula (8)) method.

In the production method passing through the above formulas (3) to (8), when either one of R ¹ and R ² is hydrogen (here, R ² = H), a secondary amino group Is preferably not involved in the condensation reaction of the above formula (7). For this purpose for example, previously converted to 2-nitrobenzenesulfonyl (Ns) group the ^{R 2} of the amine ^HNR 1 ^{R 2} prior to performing the reaction of the above formula (4) (Ns protection: the following formula (9)), the following The reaction of the above formulas (4) to (8) is carried out assuming that the Ns group is R ² (however, the reaction of the formula (4) is carried out in the presence of a base such as K ₂ CO ₃ ), and then the Ns group is deprotected. (For example, thiol treatment under basic conditions) and H on the N atom may be regenerated (the following formula (10)).

In the case where both R ¹ and R ² are hydrogen, for example, in the reaction of the above formula (4), an alkali metal azide (for example, NaN ₃ etc.) is allowed to act on the epoxide instead of amine HNR ¹ R ² to give amino. In the same manner as described above except that an azide group is introduced instead of a group, an alcohol as a reaction intermediate is prepared (the following formulas (11) to (12)), and this alcohol is used as an intermediate having a tertiary amino group. By condensing with an alcohol or an intermediate alcohol having a secondary amino group protected with Ns with a dicarboxylic acid HO ₂ C—R ⁵ —CO ₂ H, a condensation product having one azide group at one end is obtained ( Formula (13) below. Thereafter, it can be produced by converting the azide group into a primary amino group by catalytic reduction (H ₂ / Pd) or Staudinger reaction (the following formula (14)). If an Ns group is introduced, the Ns group is also deprotected.

When two different kinds of intermediate alcohols are condensed with dicarboxylic acid HO ₂ C—R ⁵ —CO ₂ H, a product obtained by simply using a plurality of types of alcohols together as in the above formula (13) is used. Although it may be a purification method, a selective monohydrolysis reaction of dimethyl ester (Japanese translations of PCT publication No. 2010-533644, Journal of Organic Synthetic Chemistry 2008, vol. 66, No. 10, 45-56.) Should be used. The refining work may be labor-saving. Specifically, a carboxylic acid half ester is obtained by hydrolyzing a carboxylic acid dimethyl ester MeO ₂ C—R ⁵ —CO ₂ Me in tetrahydrofuran (THF) or a mixed solvent of acetonitrile and water with KOH at 0 ° C. Is selectively obtained (following formula (15)), the carboxy group is protected with a tert-butyl group, and the other methyl ester is hydrolyzed under basic conditions to obtain a half ester (following formula (16) ). The half ester is condensed with the first intermediate alcohol (following formula (17)), and the tert-butyl group is selectively deprotected under mild acidic conditions to regenerate the carboxy group (following formula (18), J Org.Chem. 2006, 71, 9045-9050.), The second intermediate alcohol is condensed (the following formula (19)). The subsequent deprotection reaction and the conversion reaction of an azide group to a primary amino group when an azide group is introduced instead of an amino group may be carried out in the same manner as described above.

(Manufacturing (b): When x (y) is 2 to 3)
In the above general formula (1), when x (y) is 2 to 3, for example, it can be produced as follows. That is, a C—C bond is formed by allowing a Grignard reagent derived from an ω-haloalkene to act on a ω-hydroxyalkanal in which a hydroxy group is protected (for example, silyl protection such as TBS protection). )), And the resulting hydroxy group is protected (for example, PMB protection, etc., the following formula (21)). The terminal alkene is converted into a primary alcohol by hydroboration and subsequent basic hydrogen peroxide treatment (the following formula (22)), and the alcohol is converted into a halide (the following formula (23)). An amine HNR ¹ R ² is allowed to act on the halide to form a C—N bond (the following formula (24)), and a terminal hydroxy group is deprotected to obtain a primary alcohol as an intermediate (the following formula (25)). The condensation of the alcohol and the carboxylic acid HO ₂ C—R ⁵ —CO ₂ H and the deprotection of the hydroxy group are the same as above (the following formulas (26) to (27)).

In the production method via the above formulas (20) to (27), when either one of R ¹ and R ² is hydrogen (here, R ² = H), an Ns protecting group is added to the raw material amine. In the following, the Ns group is regarded as R ^2, and amino group introduction and functional group conversion (formulas (24) to (25)) and condensation reaction (formula (26)) are carried out in the same manner as described above. It is the same as described above that the protecting group and the Ns protecting group of the amino group may be deprotected.

When both R ¹ and R ² are hydrogen, for example, in the reaction of the above formula (24), an alkali metal azide is allowed to act instead of amine HNR ¹ R ² to introduce an azide group instead of an amino group. The intermediate alcohol is prepared in the same manner as described above, and the azide group may be converted to the primary amino group by the Staudinger reaction or catalytic reduction after the condensation reaction and deprotection as described above.

  When the target dicarboxylic acid ester compound is an asymmetric ester, the condensation reaction may be sequentially performed through the same processes as in the above formulas (15) to (19).

<2. Friction modifier>
The friction modifier according to the second aspect of the present invention comprises the dicarboxylic acid diester compound according to the first aspect of the present invention.

(Content)
The content of the dicarboxylic acid diester compound of the present invention in the friction modifier of the present invention is not particularly limited, but is preferably 50% by weight or more, more preferably 80% by weight based on the total amount of the friction modifier. % Or more, particularly preferably 90% by weight or more, and may be 100% by weight.

<3. Lubricating oil composition>
The lubricating oil composition according to the third aspect of the present invention may be referred to as a base oil and the friction modifier according to the second aspect of the present invention (hereinafter referred to as “polyfunctional dicarboxylic ester ester friction modifier”). .).

(Lubricant base oil)
The lubricating base oil in the lubricating oil composition of the present invention is not particularly limited, and mineral base oils and synthetic base oils used for ordinary lubricating oils can be used.

  Specifically, as the mineral base oil, the lubricating oil fraction obtained by subjecting the crude oil to atmospheric distillation obtained under reduced pressure is subjected to solvent removal, solvent extraction, hydrocracking, Method to isomerize GTL WAX (gas-to-liquid wax) produced by one or more processes such as solvent dewaxing, hydrorefining, etc., or wax isomerized mineral oil, Fischer-Tropsch process, etc. The lubricating base oil produced in (1) can be exemplified.

  Synthetic lubricating oils include polyalphaolefins such as 1-octene oligomers and 1-decene oligomers or their hydrides, isobutene oligomers or their hydrides, paraffins, alkylbenzenes, alkylnaphthalenes, diesters (ditridecylglutarate, di- 2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, di-2-ethylhexyl sebacate, etc., polyol esters (trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate, pentaerythritol pelargo) Acid), polyoxyalkylene glycol, dialkyl diphenyl ether, polyphenyl ether and the like. Other examples include aromatic synthetic oils such as alkylnaphthalene, alkylbenzene, and aromatic esters, or mixtures thereof.

  In the lubricating oil composition of the present invention, a mineral base oil, a synthetic base oil, or an arbitrary mixture of two or more kinds of lubricating oils selected from these can be used as the lubricating base oil. Examples thereof include one or more mineral base oils, one or more synthetic base oils, a mixed oil of one or more mineral base oils and one or more synthetic base oils, and the like.

  The kinematic viscosity, the NOACK evaporation amount, and the viscosity index of the lubricating base oil in the lubricating oil composition of the present invention can be appropriately set according to the use of the lubricating oil composition.

(Multifunctional dicarboxylic acid ester friction modifier)
The friction modifier according to the second aspect of the present invention is as already described. The content is not particularly limited. The content of the dicarboxylic acid ester compound represented by the general formula (1) based on the total amount of the lubricating oil composition may be, for example, 0.1 to 10% by weight. The preferred content can vary depending on the application. For example, when a lubricating oil composition for an automatic transmission or a continuously variable transmission is used, it is preferably 0.1% by weight or more, and more preferably 5% by weight or less.

(Other additives)
In addition to the above-described lubricating base oil and friction modifier, the lubricating oil composition of the present invention includes an ashless dispersant, an antioxidant, a friction modifier other than the dicarboxylic ester compound of the present invention, an antiwear agent, At least one selected from the group consisting of an extreme pressure agent, a metallic detergent, a viscosity index improver, a pour point depressant, a corrosion inhibitor, a rust inhibitor, a metal deactivator, an antifoaming agent and a colorant It is preferable to include.

  A known ashless dispersant can be used as the ashless dispersant. When the lubricating oil composition of the present invention contains an ashless dispersant, its content is usually 0.01% by weight or more based on the total amount of the lubricating oil composition, that is, the total amount of the lubricating oil composition is 100% by weight. The content is preferably 0.1% by weight or more. Moreover, it is 20 weight% or less normally, Preferably it is 10 weight% or less.

  A known antioxidant can be used as the antioxidant. When the antioxidant is contained in the lubricating oil composition of the present invention, the content is usually 5.0% by weight or less, preferably 3.0% by weight or less, based on the total amount of the lubricating oil composition. Moreover, it is preferably 0.1% by weight or more, more preferably 0.5% by weight or more.

  As the friction modifier other than the dicarboxylic acid ester compound of the present invention, known friction modifiers can be used. Examples include oil-based friction modifiers such as fatty acid esters, sulfur-containing molybdenum complexes such as molybdenum dithiocarbamate and molybdenum dithiophosphate, molybdenum complexes that do not contain sulfur such as molybdenum amine complexes and molybdenum-succinimide complexes, and molybdenum disulfide. And molybdenum-based friction modifiers. When these friction modifiers are contained in the lubricating oil composition of the present invention, the content is usually 0.005 wt% or more and 5 wt% or less based on the total amount of the lubricating oil composition.

  As the antiwear agent or extreme pressure agent, known antiwear agents or extreme pressure agents can be used. Examples thereof include phosphorus compounds such as (mono, di, tri-thio) (sub) phosphate esters and zinc dithiophosphate, and sulfur-containing compounds such as disulfides, sulfurized olefins, sulfurized fats and oils, and dithiocarbamates. . When these lubricants are contained in the lubricating oil composition of the present invention, the content thereof is usually 0.005 wt% or more and 5 wt% or less based on the total amount of the lubricating oil composition.

  As the metal detergent, a known metal detergent can be used. Examples include alkali metal sulfonates, alkaline earth metal sulfonates, alkali metal phenates, alkaline earth metal phenates, alkali metal salicylates, alkaline earth metal salicylates, and mixtures thereof. These metallic detergents may be overbased. When the metallic detergent is contained in the lubricating oil composition of the present invention, the content is not particularly limited. However, in the case of an automatic transmission or a continuously variable transmission, the metal element conversion amount is usually 0.01% by weight or more and 5% by weight or less based on the total amount of the lubricating oil composition.

A known viscosity index improver can be used as the viscosity index improver. For example, various methacrylic acids containing a so-called non-dispersible viscosity index improver such as a polymer or copolymer of one or more monomers selected from various methacrylic esters and hydrogenated products thereof, and further a nitrogen compound So-called dispersed viscosity index improver copolymerized with ester, non-dispersed or dispersed ethylene-α-olefin copolymer and hydride thereof, polyisobutylene and hydrogenated product thereof, hydride of styrene-diene copolymer , Styrene-maleic anhydride copolymer, and polyalkylstyrene. The average molecular weight of the viscosity index improver is usually 5,000 or more and 1,000,000 or less in terms of weight average molecular weight in the case of, for example, dispersed and non-dispersed polymethacrylates. For example, when polyisobutylene or a hydride thereof is used for an internal combustion engine, the number average molecular weight is usually 800 or more and 5,000 or less. For example, when an ethylene-α-olefin copolymer or a hydride thereof is used for an internal combustion engine, the number average molecular weight is usually 800 or more and 500,000 or less.
When these viscosity index improvers are contained in the lubricating oil composition of the present invention, the content thereof is usually 0.1% by weight or more and 20% by weight or less based on the total amount of the lubricating oil composition.

  As the pour point depressant, a known pour point depressant such as a polymethacrylate polymer can be appropriately used according to the properties of the lubricating base oil to be used. When the lubricating oil composition of the present invention contains a pour point depressant, the content thereof is usually 0.01% by weight or more and 1% by weight or less based on the total amount of the lubricating oil composition.

  As the corrosion inhibitor, for example, known corrosion inhibitors such as benzotriazole, tolyltriazole, thiadiazole, and imidazole compounds can be used. When these corrosion inhibitors are contained in the lubricating oil composition of the present invention, the content is usually 0.005 wt% or more and 5 wt% or less based on the total amount of the lubricating oil composition.

  As the rust preventive agent, for example, known rust preventive agents such as petroleum sulfonate, alkylbenzene sulfonate, dinonylnaphthalene sulfonate, alkenyl succinate, and polyhydric alcohol ester can be used. When these antirust agents are contained in the lubricating oil composition of the present invention, the content thereof is usually 0.005 wt% or more and 5 wt% or less based on the total amount of the lubricating oil composition.

  Examples of the metal deactivator include imidazoline, pyrimidine derivatives, alkylthiadiazole, mercaptobenzothiazole, benzotriazole and derivatives thereof, 1,3,4-thiadiazole polysulfide, 1,3,4-thiadiazolyl-2,5-bis. Known metal deactivators such as dialkyldithiocarbamate, 2- (alkyldithio) benzimidazole, and β- (o-carboxybenzylthio) propiononitrile can be used. When these metal deactivators are contained in the lubricating oil composition of the present invention, the content is usually 0.005 wt% or more and 1 wt% or less based on the total amount of the lubricating oil composition.

  As the antifoaming agent, for example, known antifoaming agents such as silicone, fluorosilicone, and fluoroalkyl ether can be used. When these antifoaming agents are contained in the lubricating oil composition of the present invention, the content thereof is usually 0.0005 wt% or more and 1 wt% or less based on the total amount of the lubricating oil composition.

  As the colorant, for example, a known colorant such as an azo compound can be used.

(Use)
The lubricating oil composition of the present invention contains the friction modifier (polyfunctional dicarboxylic acid diester-based friction modifier) according to the second aspect of the present invention, thereby providing improved anti-shudder life and good transmission characteristics. On the other hand, since the friction coefficient between metals is also increased, the transmission torque capacity can be improved. Therefore, it can be preferably used as an automatic transmission oil or a continuously variable transmission oil.

  Hereinafter, based on an Example and a comparative example, it demonstrates further more concretely about this invention. However, the present invention is not limited to these examples.

<Production Example 1>
It is the manufacture example which manufactured the dicarboxylic acid ester compound which concerns on the 1st aspect of this invention.
In the above general formula (1), R ¹ = R ² = R ³ = R ⁴ = mixture of hexadecyl group and octadecyl group, R ⁵ = cyclohexane-1,2-diyl group, m = n = 1 The dicarboxylic acid ester compound A of the aspect which is x = y = 1 was manufactured.
In a 200 ml flask, 10.0 g (0.035 mol) of diglycidyl cyclohexanedicarboxylate and 35.4 g (0.07 mol) of Phamine D86 (secondary amine manufactured by Kao Chemical Company, hexadecyl group: 30%, octadecyl group: 66%) The mixture was heated to 120 ° C. with stirring, and reacted for 7 hours while confirming the progress of the reaction by infrared spectroscopy. After the reaction, the reaction mixture was cooled to room temperature to obtain 43.5 g of a yellow gel product (yield 96%).

<Example 1 and Comparative Examples 1-3>
A lubricating oil composition (Example 1) according to the third aspect of the present invention and a comparative lubricating oil composition (Comparative Examples 1 to 3) were prepared so that the compositions shown in Table 1 were obtained. In the table, the numerical values of the component amounts are all based on the total amount of the composition, and “wt%” means wt% and “wt ppm” means ppm by weight.

(Evaluation of friction coefficient between metals)
Using a block-on-ring friction tester (LFW-1 manufactured by FALEX), the friction coefficient between metals was evaluated under the condition that the lubricating oil composition was present on the friction surface. The test conditions were a load of 889 N, a surface pressure of 0.54 GPa, a sliding speed of 0.125 m / s, a test temperature of 80 ° C., a test time of 3 minutes, and the friction coefficient of 1.5 to 2.5 minutes within the test time was averaged. The average friction coefficient was evaluated. The results are also shown in Table 1. If the coefficient of friction between metals is 0.110 or more under the conditions of this test, it can be said that a good transmission torque capacity can be secured and that it has a good speed change characteristic.

(Evaluation of anti-shudder life)
Using a low-speed slip tester specified in JASO M349: 2010, the anti-shudder life of the lubricating oil composition was evaluated. The test method was based on JASO M349: 2010, and μ-V curves were measured at temperatures of 40 ° C., 80 ° C., and 120 ° C. Judgment of the anti-shudder life is in accordance with JASO M315: 2004, and the μ-V curve at the measured temperature is approximated by a least-squares function with a quintic function, and the slip function (V) is 0.3 m / The gradient was obtained by differentiating at two points of s and 0.9 m / s, and the lifetime was determined when any of the four gradient values at 40 ° C. and 80 ° C. became negative. The results are also shown in Table 1. If the shudder prevention life is 100 hours or more under the conditions of this test, it can be said that the ability to maintain the shudder prevention performance is excellent.

(Evaluation results)
The lubricating oil composition of Example 1 in which the dicarboxylic acid ester compound A of the present invention was blended as a friction modifier showed excellent results in both the intermetal friction coefficient and the shudder prevention life.
The lubricating oil composition of Comparative Example 1 in which no friction modifier was blended did not have anti-shudder performance.
Further, the lubricating oil compositions of Comparative Examples 2 and 3 each containing glycerol monooleate and alkyldiethanolamine, which are conventionally known general friction modifiers, were remarkably inferior in the anti-shudder life. In addition, the lubricating oil composition of Comparative Example 3 did not reach a satisfactory level in the coefficient of friction between metals.

  From the above results, according to the lubricating oil composition containing the dicarboxylic acid ester compound of the present invention as a friction modifier, it is possible to simultaneously realize a long shudder prevention life and a good transmission torque capacity due to a high intermetal friction coefficient. Indicated.

  The lubricating oil composition using the dicarboxylic acid ester compound of the present invention as a friction modifier can be preferably used as a transmission oil, and particularly preferably used as an automatic transmission oil or a continuously variable transmission oil. In particular, it can be preferably used as a lubricating oil used in a transmission having a torque converter having a lock-up mechanism, and particularly as a lubricating oil used in a transmission having a torque converter that performs slip control in a lock-up clutch.

Claims (5)

A dicarboxylic acid ester compound represented by the following general formula (1).

[In the formula (1), R ^{1 to} R ⁴ each independently represent hydrogen or a hydrocarbyl group having 1 to 30 carbon atoms, and R ^{1 to} R ⁴ may be the same or different, and R ^{1 to} R ⁴ At least one is a hydrocarbyl group having 8 to 30 carbon atoms; R ⁵ represents a single bond or a hydrocarbylene group having 1 to 30 carbon atoms; m and n are each independently an integer of 1 to 4; x and y are each independently an integer of 1 to 3. ] In the formula (1), at least one of R ¹ and R ² and at least one of R ³ and R ⁴ is a hydrocarbyl group having 1 to 30 carbon atoms,
The dicarboxylic acid ester compound according to claim 1.   A friction modifier comprising the dicarboxylic acid ester compound according to claim 1. Lubricating base oil,
A lubricating oil composition comprising the friction modifier according to claim 3. Lubricating base oil,
A lubricating oil composition for a continuously variable transmission, comprising the friction modifier according to claim 3.