WO2018043495A1

WO2018043495A1 - Lubricant composition

Info

Publication number: WO2018043495A1
Application number: PCT/JP2017/030966
Authority: WO
Inventors: 剛辰巳; 長谷川　慎治; 雄治松井
Original assignee: Ｊｘｔｇエネルギー株式会社
Priority date: 2016-08-31
Filing date: 2017-08-29
Publication date: 2018-03-08
Also published as: JPWO2018043495A1; JP7034921B2

Abstract

A lubricant composition for variable transmission, which contains: a lubricant base oil; a first friction regulator that has a first hydrocarbon group containing a linear hydrocarbon chain that has 12 or more carbon atoms and a polar group containing an oxygen atom and/or a nitrogen atom; and a second friction regulator that has a second hydrocarbon group and a polar group containing an oxygen atom and/or a nitrogen atom, said second hydrocarbon group having 12 or more carbon atoms and not containing a linear hydrocarbon chain that has 12 or more carbon atoms.

Description

Lubricating oil composition

The present invention relates to a lubricating oil composition.

Lubricating oil (transmission lubricating oil) for transmitting power from the engine to the transmission is used in transmissions such as automatic transmission oil and continuously variable transmission oil. A friction modifier is blended with the lubricating oil for the transmission in order to adjust its friction characteristics. Examples of the friction modifier include an amine compound having a linear alkyl group having 12 to 30 carbon atoms or a linear alkenyl group, a fatty acid amide, a fatty acid metal salt, a fatty acid having an α-branched structure having 12 or more carbon atoms, and an amine. And the like are known (see Patent Documents 1 to 4 below).

JP 2008-106167 A JP 2005-146148 A JP-A-10-219269 JP 2007-238524 A

In addition to high transmission torque capacity for improving power transmission efficiency, transmission lubricants are required to have anti-shudder properties to improve riding comfort.

However, the anti-shudder property and the transmission torque capacity are generally in a trade-off relationship, and it is difficult to achieve both of these characteristics using a conventional transmission lubricant. For example, when a conventional transmission lubricating oil having a high transmission torque capacity is used, shudder (abnormal vibration) is likely to occur, and the riding comfort of an automobile may be impaired. On the other hand, when the prevention of shudder of transmission lubricant is improved, the friction coefficient of the wet clutch in the automatic transmission and the friction coefficient between the metal belt or metal chain and the metal pulley in the continuously variable transmission are reduced. As a result, transmission loss increases.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a lubricating oil composition capable of achieving both excellent anti-shudder resistance and a sufficiently high torque capacity.

In order to solve the above problems, the present invention has a lubricating base oil, a first hydrocarbon group containing a straight hydrocarbon chain having 12 or more carbon atoms, and a polar group containing oxygen and / or nitrogen. A first friction modifier, a second hydrocarbon group having 12 or more carbon atoms and not containing a straight hydrocarbon chain having 12 or more carbon atoms, and a polar group containing oxygen and / or nitrogen And a lubricating oil composition for a transmission containing two friction modifiers.

According to the above-mentioned lubricating oil composition for a transmission, the combination of the first friction modifier and the second friction modifier sufficiently suppresses a decrease in transmission torque capacity, and provides excellent shudder prevention. Can be achieved.

According to the study of the present inventor, the first friction modifier has excellent anti-shudder properties, but when used alone, the friction coefficient of the friction surface is excessively decreased and the transmission torque capacity tends to decrease. There is. On the other hand, when the second friction modifier is used alone, there is a tendency that sufficient anti-shudder properties cannot be obtained. Therefore, when the first friction modifier and the second friction modifier are used in combination, both the first friction modifier and the second friction modifier are adsorbed on the friction surface, and the first friction modifier It is surmised that the excessive decrease in the coefficient of friction seen when the first friction modifier is used alone is suppressed. The combined effect of these friction modifiers is considered to be able to achieve both excellent shudder prevention and high transmission torque capacity, which were difficult to achieve with conventional transmission lubricants.

Based on the total amount of the lubricating oil composition, the content of the first friction modifier can be 0.01 to 5% by mass, and the content of the second friction modifier is 0.01 to 5%. It can be 5 mass%.

According to the present invention, there is provided a lubricating oil composition capable of achieving both excellent anti-suddering properties and a sufficiently high torque capacity.

It is a figure which shows IR measurement data in manufacture example 1. It is a figure which shows IR measurement data in manufacture example 2. It is a figure which shows IR measurement data in manufacture example 3.

Hereinafter, preferred embodiments of the present invention will be described in detail.

The transmission lubricating oil composition according to the present embodiment includes a lubricating base oil, a first friction modifier, and a second friction modifier.

[Lubricant base oil]
The lubricating base oil used in the present embodiment is not particularly limited, and any of mineral oil and synthetic oil can be used. Various conventionally known oils can be used as the mineral oil, and examples thereof include paraffin-based mineral oil, intermediate-based mineral oil, and naphthene-based mineral oil. Specifically, light neutral oil, intermediate neutral oil, heavy neutral oil, bright stock, etc. by solvent refining or hydrogen refining can be mentioned. Further, GTL base oil obtained by isomerizing wax may be used, and the effect becomes higher as the degree of purification increases.

As the synthetic oil, various conventionally known oils can be used as well. For example, poly α-olefin (including α-olefin copolymer), polybutene, polyol ester, dibasic acid ester, phosphoric acid ester, polyphenyl ether, alkylbenzene, alkylnaphthalene, polyoxyalkylene glycol, neopentyl glycol, silicone Oil, trimethylolpropane, pentaerythritol, hindered ester, and the like can be used.

These lubricant base oils can be used singly or in combination of two or more, and may be used in combination of mineral oil and synthetic oil.

The kinematic viscosity of the lubricating base oil can be appropriately selected according to the use and purpose of the lubricating oil composition. For example, when the lubricating oil composition according to the present embodiment is used as a drive system lubricating oil, the upper limit value of the kinematic viscosity at 100 ° C. of the lubricating base oil is preferably 30 mm ² / s or less, more preferably 20 mm ² / s or less, more preferably 10 mm ² / s or less. On the other hand, the lower limit of the kinematic viscosity at 100 ° C. of the lubricating base oil is preferably 1 mm ² / s or more, more preferably 2 mm ² / s or more, and further preferably 3 mm ² / s or more. When the kinematic viscosity at 100 ° C. is in the above range, friction at sliding portions such as gear bearings and clutches of the automatic transmission can be sufficiently reduced and the low temperature characteristics are also improved. On the other hand, if the kinematic viscosity at 100 ° C. exceeds 30 mm ² / s, the fuel efficiency deteriorates and the low-temperature viscosity tends to be too high. Also, if the kinematic viscosity at 100 ° C. is less than 1 mm ² / s, the lubrication performance deteriorates, such as the amount of wear increases in sliding parts such as gear bearings and clutches of automatic transmissions, and the evaporability increases and lubrication occurs. Oil consumption may increase.

Moreover,% C _A of the lubricating base oil, from the viewpoint of low-temperature properties, preferably not more than 20, more preferably 10 or less.

In addition, the viscosity index, the NOACK evaporation amount, and the like of the lubricating base oil used in this embodiment can be appropriately set according to the use of the lubricating oil composition.

[First friction modifier]
The first friction modifier used in the present embodiment has a first hydrocarbon group containing a straight hydrocarbon chain having 12 or more carbon atoms and a polar group containing oxygen and / or nitrogen.

The first hydrocarbon group includes a linear hydrocarbon chain having 12 or more carbon atoms. A straight hydrocarbon chain refers to a structure in which carbon atoms in a hydrocarbon are bonded without branching. Although it will not restrict | limit especially if carbon number of the said linear hydrocarbon chain is 12 or more, Preferably it is C14 or more, More preferably, it is C16 or more. The upper limit of the carbon number of the hydrocarbon chain is not particularly limited, but is preferably 30 or less. The straight hydrocarbon chain may be saturated or unsaturated. The first hydrocarbon group may be, for example, a group composed of a straight hydrocarbon chain having 12 or more carbon atoms, and has a straight hydrocarbon chain having 12 or more carbon atoms and a carbon atom that serves as a branch point. It may be a group.

When the first hydrocarbon group is a group consisting of a straight chain hydrocarbon chain having 12 or more carbon atoms, the straight chain hydrocarbon chain is preferably saturated. However, when the carbon number of the linear hydrocarbon chain exceeds 16, from the viewpoint of securing solubility in the base oil, the linear hydrocarbon chain is preferably unsaturated, and has a structure containing one double bond. It is more preferable to have.

When the first hydrocarbon group is a linear hydrocarbon chain having 12 or more carbon atoms and a group having a carbon atom that serves as a branch point, the linear hydrocarbon chain is preferably saturated. As long as it has a straight-chain hydrocarbon chain having 12 or more carbon atoms, the position of the carbon atom serving as the branch point is not particularly limited, and may be present at any position. Further, the number of carbon atoms serving as branch points is preferably 2 or less, more preferably 1.

Examples of the first hydrocarbon group according to this embodiment include the following formula (1-a), formula (1-b), formula (2-a), formula (2-b), and the like.

The polar group containing oxygen and / or nitrogen is not particularly limited as long as it is a polar group contained in the friction modifier used in the lubricating oil composition for transmissions. Examples of the structure include at least one functional group represented by the following formulas (3) to (21).

(In the formula, * represents a site independently bonded to the first hydrocarbon group, and in formula (6), X is selected from the group consisting of Na, K, Zn, Ca, Mg, B and Al) Represents an atom, h represents the valence of X, and in formula (7), Y represents an atom selected from the group consisting of Na, K, Zn, Ca, Mg, B, and Al, and i represents the valence of Y. In formula (8), j and k each independently represent an integer of 1 to 10, in formula (9), l and m each independently represent an integer of 1 to 10, and formula (10) Wherein n represents an integer of 0 to 10, in formula (11), o represents an integer of 0 to 10, in formula (12), p represents an integer of 0 to 10, and in formula (13), q represents an integer of 0 to 10.)

In the formulas (8) and (9), j, k, l and m are not particularly limited as long as they are each independently an integer of 0 to 10, preferably an integer of 1 to 5, more preferably 1 It is an integer of ˜3, more preferably 1.

In formula (10), formula (11), formula (12) and formula (13), n, o, p and q are each independently an integer of 0 to 10, but preferably 1 to It is an integer of 5, more preferably an integer of 1 to 4.

As the first friction modifier, only those having a single polar group can be used, or those having different polar groups can be used in any combination. From the viewpoint of having sufficient adsorptive power from a low temperature range and imparting further excellent anti-shudder performance to the lubricating oil composition, the first friction modifier is represented by the formula (4), formula (8), formula (9 ), Formula (10), formula (16), formula (19) and at least one functional group represented by formula (20), preferably at least one functional group represented by formula (8) More preferably.

In addition, examples of the first friction modifier include compounds represented by the following formulas (22) to (25). These first friction modifiers can be used singly or in combination of two or more.

(In the formula, n represents an integer of 0 to 10.)

The first friction modifier may be a commercially available product or may be synthesized by a known method.

In the lubricating oil composition according to this embodiment, the content of the first friction modifier is not particularly limited, but is preferably 0.01 to 5% by mass, more preferably based on the total amount of the lubricating oil composition. The content is 0.01 to 3% by mass, and more preferably 0.01 to 1% by mass. When the content of the first friction modifier is within the above range, it is possible to more effectively impart excellent anti-sudder performance to the lubricating oil composition.

[Second friction modifier]
The second friction modifier used in the present embodiment contains a second hydrocarbon group having 12 or more carbon atoms and not containing a straight hydrocarbon chain having 12 or more carbon atoms, and oxygen and / or nitrogen. It has polar groups.

The second hydrocarbon group is a group having 12 or more carbon atoms and not containing a straight hydrocarbon chain having 12 or more carbon atoms. The second hydrocarbon group is not particularly limited as long as it does not contain a linear hydrocarbon chain having 12 or more carbon atoms, but preferably has 14 or more carbon atoms, more preferably 16 or more carbon atoms. The upper limit of the carbon number of the second hydrocarbon group is not particularly limited, but is preferably 30 or less. The second hydrocarbon group may be saturated or unsaturated.

The second hydrocarbon group is a group that does not include a straight hydrocarbon chain having 12 or more carbon atoms, but preferably does not include a straight hydrocarbon chain having 10 or more carbon atoms, and is a straight chain having 8 or more carbon atoms. More preferably, it does not contain hydrocarbon chains. The second hydrocarbon group preferably has one or more carbon atoms that serve as branch points.

Examples of such a second hydrocarbon group include the following formula (26-a), formula (26-b), formula (27-a), formula (27-b), and the like.

The polar group containing oxygen and / or nitrogen in the second friction modifier is not particularly limited as long as it is a polar group contained in the friction modifier used in the lubricating oil composition for a transmission. Specific examples of such a polar group structure include at least one functional group represented by the following formulas (28) to (46).

(In the formula, * represents a site independently bonded to the second hydrocarbon group, and in formula (31), X is selected from the group consisting of Na, K, Zn, Ca, Mg, B, and Al) Represents an atom, h represents a valence of X, and in formula (32), Y represents an atom selected from the group consisting of Na, K, Zn, Ca, Mg, B, and Al, and i represents a valence of Y. In formula (33), j and k each independently represent an integer of 1 to 10, in formula (34), l and m each independently represents an integer of 1 to 10, and formula (35) In which n represents an integer of 0 to 10, in formula (36), o represents an integer of 0 to 10, in formula (37), p represents an integer of 0 to 10, and in formula (38), q represents an integer of 0 to 10.)

In formula (33) and formula (34), j, k, l and m are not particularly limited as long as they are each independently an integer of 0 to 10, preferably an integer of 1 to 5, more preferably 1. It is an integer of ˜3, more preferably 1.

In formula (35), formula (36), formula (37) and formula (38), n, o, p and q are each independently an integer of 0 to 10, preferably 1 to It is an integer of 5, more preferably an integer of 1 to 4.

As the second friction modifier, only those having a single polar group can be used, or those having different polar groups can be used in any combination. From the viewpoint of having a sufficient adsorptive power at a high temperature range and imparting a higher torque capacity to the lubricating oil composition, the second friction modifier is represented by the formula (35), formula (36), formula (37). And at least one functional group represented by formula (38), and more preferably at least one functional group represented by formula (35).

Examples of the second friction modifier include compounds represented by the following formula (47) and formula (48). These 2nd friction modifiers can be used individually by 1 type or in combination of 2 or more types.

(In the formula, n represents an integer of 0 to 10.)

(In the formula, n represents an integer of 0 to 10.)

In the lubricating oil composition according to this embodiment, the content of the second friction modifier is not particularly limited, but is preferably 0.01 to 5% by mass, more preferably based on the total amount of the lubricating oil composition. The content is 0.01 to 3% by mass, and more preferably 0.01 to 1% by mass. When the content of the second friction modifier is within the above range, a higher torque capacity can be imparted to the lubricating oil composition.

In the lubricating oil composition according to the present embodiment, the content ratio of the first friction modifier and the second friction modifier is, for example, A for the number of moles of the first friction modifier, and the second friction modifier. When the number of moles is B, the molar ratio is preferably A: B = 1: 10 to 10: 1, more preferably 1: 5 to 5: 1, and 1: 2 to 2: 1 is more preferable, and 1: 1 is particularly preferable. If the content ratio of both is in the above range, excellent anti-sudder performance and sufficiently high torque capacity can be achieved at a higher level.

[Optional additives]
The lubricating oil composition according to the present embodiment further contains an optional additive other than the first friction modifier and the second friction modifier as necessary for the purpose of further improving the performance. Can do.

As the additive, an additive that can be added to the lubricating oil composition for a transmission can be used without particular limitation. Additives include, for example, viscosity index improvers, ashless dispersants and / or friction modifiers other than the first friction modifier and the second friction modifier, wear inhibitors, metal detergents, metal inertness Examples thereof include an agent, an antioxidant, and an antifoaming agent. These additives can be used individually by 1 type or in combination of 2 or more types.

Examples of the viscosity index improver include non-dispersed or dispersed viscosity index improvers. Specifically, non-dispersed or dispersed polymethacrylates, non-dispersed or dispersed ethylene-α-olefin copolymers or hydrides thereof, polyisobutylene or hydrides thereof, styrene-diene hydrogenated copolymers, Examples thereof include styrene-maleic anhydride ester copolymers, polymethacrylate-styrene copolymers, polymethacrylate-olefin copolymers, and polyalkylstyrenes. The weight average molecular weight of these viscosity index improvers is not particularly limited, and is usually 10,000 to 1,000,000. The content of the viscosity index improver is not particularly limited, but is usually 0.5 to 35% by mass based on the total amount of the lubricating oil composition.

Ashless dispersants and / or friction modifiers other than the first friction modifier and the second friction modifier include amine compounds, imide compounds, fatty acid esters, fatty acid amides, fatty acids, aliphatic alcohols, aliphatic ethers, molybdenum Examples thereof include organic molybdenum compounds such as dithiophosphate (MoDTP) and molybdenum dithiocarbamate (MoDTC), graphite, molybdenum disulfide, antimony sulfide, boron compounds, polytetrafluoroethylene, and the like. The content of the ashless dispersant and / or the friction modifier is not particularly limited, but is usually 0.1 to 10% by mass based on the total amount of the lubricating oil composition.

As the antiwear agent, for example, a sulfur type antiwear agent, a phosphorus type antiwear agent and the like can be used. Examples of the sulfur-based antiwear agent include disulfides, polysulfides, sulfurized olefins, sulfurized fats and oils, sulfurized esters, dithiocarbamates, zinc dithiocarbamates and the like. Examples of the phosphorus-based antiwear agent include phosphoric acid, monothiophosphoric acid, dithiophosphoric acid, trithiophosphoric acid, tetrathiophosphoric acid, phosphate ester, phosphite ester, and thiophosphate ester. The content of the antiwear agent is not particularly limited, but is usually 0.01 to 10% by mass based on the total amount of the lubricating oil composition.

Examples of metal detergents include calcium sulfonate, magnesium sulfonate, barium sulfonate, calcium salicylate, magnesium salicylate, calcium phenate, barium phenate, and other normal salts, basic salts, and overbased salts. Can be mentioned. The content of the metallic detergent is not particularly limited, but is usually 0.1 to 10% by mass based on the total amount of the lubricating oil composition.

Examples of the metal deactivator include imidazoline, pyrimidine, thiadiazole, mercaptobenzothiazole, benzotriazole, and derivatives thereof. The content of the metal deactivator is not particularly limited, but is usually 0.01 to 10% by mass based on the total amount of the lubricating oil composition.

Examples of the antioxidant include phenol-based, amine-based, copper-based and molybdenum-based antioxidants. Specifically, amine-based antioxidants such as alkylated diphenylamine, phenyl-α-naphthylamine, alkylated-α-naphthylamine, 2,6-di-t-butyl-4-methylphenol, 4,4′-methylenebis And hindered phenol antioxidants such as (2,6-di-t-butylphenol). The content of the antioxidant is not particularly limited, but is usually 0.05 to 5% by mass based on the total amount of the lubricating oil composition.

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.

The lubricating oil composition according to the present embodiment is suitable as a lubricating oil composition for transmissions such as automatic transmission oil and continuously variable transmission oil because it can maintain a balance between excellent anti-shudder properties and high torque capacity. It is. It can also be used as a lubricating oil for construction machines, agricultural machines, manual transmissions, motorcycle gasoline engines, diesel engines, gas engines, shock absorber oils, etc., equipped with transmissions having wet clutches and wet brakes.

Hereinafter, the present invention will be described more specifically based on examples and comparative examples. However, the following examples are not intended to limit the present invention.

[Examples 1 to 9, Comparative Examples 1 to 10]
Lubricating oil compositions having the compositions shown in Tables 1 and 2 were prepared using the following base oils and additives. The content ratio of each component in Tables 1 and 2 indicates the content ratio based on the total amount of the lubricating oil composition.

(Base oil)
a1: Hydrorefined mineral oil (40 ° C. kinematic viscosity: 19.4 mm ² / s, 100 ° C. kinematic viscosity: 4.2 mm ² / s, viscosity index: 125, sulfur content: less than 1 ppm)

(First friction modifier)
b1: Compound represented by the following formula (22).

b2: Compound represented by the following formula (23).

b3: a compound represented by the following formula (25), wherein n is 3.

(Second friction modifier)
c1: A compound represented by the following formula (47), wherein n is 3.

c2: A compound represented by the following formula (48), wherein n is 3.

(Other additives)
d1: Non-dispersed polymethacrylate viscosity index improver (weight average molecular weight: 20000)
d2: Non-boronated succinimide dispersant [bis-type alkenyl succinimide (alkenyl group: polyisobutenyl group of Mw1000, polyamine moiety: tetraethylenepentamine), nitrogen content: 1.3% by mass]
d3: Boronated succinimide dispersant [Bis type alkenyl succinimide (alkenyl group: polyisobutenyl group of Mw1000, polyamine moiety: tetraethylenepentamine), nitrogen content: 1.3% by mass, boron content: 0.3 mass%)
d4: Phosphite ester antiwear agent (dialkyl phosphite)
d5: Overbased calcium sulfonate metal detergent (TBN300, calcium content: 12% by mass)
d6: Metal deactivator (thiadiazole, sulfur content: 36% by mass)
d7: hindered phenol antioxidant d8: antifoaming agent (polydimethylsiloxane)

Commercially available products were used as the friction modifiers b1 and b2. The friction modifier b3 and the friction modifiers c1 and c2 were synthesized as follows.

(Production Example 1: Synthesis of friction modifier (b3))
A flask equipped with a nitrogen inlet tube, a condenser, a Dean-Stark trap and a stirring device was charged with 178 g of oleic acid, 59 g of tetraethylenepentamine, and 500 ml of xylene. After the inside of the flask was purged with nitrogen while stirring, the reaction was carried out for 20 hours while heating to 160 ° C. and refluxing. Completion of the reaction was confirmed by IR. IR measurement data is shown in FIG. After completion of the reaction, the solvent was removed by distillation to obtain a friction modifier (b3).
(Production Example 2: Synthesis of friction modifier (c1))
A friction modifier (c1) was obtained in the same manner as in Production Example 1, except that 178 g of isostearic acid was used instead of 178 g of oleic acid. IR measurement data is shown in FIG.

(Production Example 3: Synthesis of friction modifier (c2))
A friction modifier (c2) was obtained in the same manner as in Production Example 1, except that 160 g of 2-hexyldecanoic acid was used instead of 178 g of oleic acid. IR measurement data is shown in FIG.

[Evaluation test of lubricating oil composition]
(Shudder prevention)
The anti-shudder property of each lubricating oil composition prepared above was calculated according to JASO M349: 2010. Specifically, an approximate expression showing the μ-V characteristic at 40 ° C. of each lubricating oil composition prepared above was obtained, and dμ / dV (dμ / dV (0.3) at a sliding speed of 0.3 m / s. ) As for the anti-shudder property, it is judged that the one having a positive value of “dμ / dV (0.3)” is excellent in the anti-shudder property.

(Torque capacity)
The torque capacities of the lubricating oil compositions prepared in Examples 1 to 7 and Comparative Examples 1 to 8 were measured using a low speed slip test device (LVFA). It was calculated according to 2010, and was obtained by calculating the friction coefficient μ at a sliding speed of 0.06 m / s in the μ-V characteristic.

The torque capacities of the lubricating oil compositions prepared in Examples 8 to 9 and Comparative Examples 9 to 10 were calculated according to the JASO M358 low load method using a friction and wear tester (LFW-1), and the sliding speed was calculated. It was determined by calculating the friction coefficient μ at 0.075 m / s.

Tables 3 and 4 show the results of evaluation tests of the lubricating oil compositions of Examples 1 to 9 and Comparative Examples 1 to 10.

Claims

Lubricating base oil,
A first friction modifier having a first hydrocarbon group containing a straight hydrocarbon chain having 12 or more carbon atoms and a polar group containing oxygen and / or nitrogen;
A second friction modifier having a second hydrocarbon group having 12 or more carbon atoms and not containing a straight hydrocarbon chain having 12 or more carbon atoms, and a polar group containing oxygen and / or nitrogen;
A lubricating oil composition for a transmission, comprising:
Based on the total amount of the lubricating oil composition, the content of the first friction modifier is 0.01 to 5% by mass, and the content of the second friction modifier is 0.01 to 5% by mass. The lubricating oil composition for a transmission according to claim 1.