JP2008127434A - Lubricating oil additive and lubricating oil composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a lubricating oil additive for providing a high coefficient of static friction and a lubricating oil composition obtained by mixing the same with a base oil. <P>SOLUTION: The lubricating oil additive is the reaction product of (A) a succinimide, (B) a phenol represented by the formula (1) (wherein, R is hydrogen or a 1-8C hydrocarbon group; x is 1 or 2) and (C) an aldehyde or ketone represented by the formula (2) (wherein, R<SP>1</SP>and R<SP>2</SP>are each hydrogen or a 1-20C hydrocarbon group). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lubricating oil additive and a lubricating oil composition obtained by blending it with a base oil. Specifically, the present invention relates to a lubricating oil composition having a high static friction coefficient (high wet friction material torque capacity) and used as an automatic transmission oil or a continuously variable transmission oil.

In recent years, against the background of the global carbon dioxide emission problem and the increase in global energy demand, there has been an increasing demand for fuel saving in automobiles. Among them, the transmission is also required to improve the power transmission efficiency as compared with the prior art, and the lubricating oil which is an important component of the transmission is also required to have a high torque capacity.
Conventionally, lubricating oils for automatic transmissions or continuously variable transmissions have been provided with friction modifiers such as phosphate esters, fatty acid esters, fatty acid amides, imide-based dispersants, and / or Or the metal detergents, such as its derivative and calcium sulfonate, were mix | blended (for example, patent documents 1-3).

JP-A-2005-146148 Japanese Patent Laid-Open No. 10-265793 JP-A-10-219269

In order to increase the static friction coefficient of the lubricating oil, it is conceivable to add a large amount of a succinimide dispersant or a metal additive, or to reduce the amount of the friction modifier added. However, the compounding formulations disclosed in Patent Documents 1 to 3 cannot achieve both a sufficiently high static friction coefficient and other required friction characteristics (μ-V characteristics, friction performance maintenance). That is, increasing the additive amount of the metal additive increases the aggressiveness of the lubricant to the friction material, and increasing the additive amount of the succinimide dispersant or decreasing the additive amount of the friction modifier makes it resistant to shudder. This is because problems such as deterioration in performance (μ-V characteristics) and anti-shudder life occur.
That is, the lubricating oils known so far are insufficient for improving the coefficient of static friction required as transmission oil. Further, conventionally known succinimide dispersants do not contribute to the improvement of the coefficient of static friction of the lubricating oil.
In view of the above problems, an object of the present invention is to provide a lubricating oil additive capable of imparting a particularly high static friction coefficient and a lubricating oil composition obtained by blending it with a base oil.

In order to solve the above problems, the present invention provides the following lubricating oil additive and lubricating oil composition.
1. Lubricant characterized by being a reaction product of (A) succinimide, (B) phenol represented by the following formula (1), and (C) aldehyde or ketone represented by the following formula (2) Oil additive.

（式中、Ｒは水素または炭素数１〜８の炭化水素基を示し、xは１または２である。）

(In the formula, R represents hydrogen or a hydrocarbon group having 1 to 8 carbon atoms, and x is 1 or 2.)

（式中、Ｒ^１、Ｒ^２はそれぞれ水素または炭素数１〜２０の炭化水素基を示す。）

(In the formula, R ¹ and R ² each represent hydrogen or a hydrocarbon group having 1 to 20 carbon atoms.)

2. 2. The lubricating oil additive as described in 1 above, wherein x in the formula (1) is 1.
3. 3. The lubricating oil additive according to 1 or 2, wherein any of R ¹ and R ² in the formula (2) is hydrogen.
4). In the lubricating oil additive according to any one of 1 to 3, when the reaction product is produced, the molar charge ratio of the components (A) to (C) is (A) :( B) :( C ) = 1: 1 to 10: 1 to 10 in a lubricating oil additive.
5. A lubricating oil composition, wherein the lubricating oil additive according to any one of the above 1 to 4 is blended with a base oil.
6). 6. The lubricating oil composition as described in 5 above, which is for a transmission.
7). 7. The lubricating oil composition as described in 6 above, which is for a transmission having a wet clutch or a wet brake.
8). The lubricating oil composition as described in any one of 5 to 7 above, which is an automatic transmission oil or a continuously variable transmission oil.

  ADVANTAGE OF THE INVENTION According to this invention, the lubricating oil additive which can provide a high static friction coefficient (high wet friction material torque capacity) can be provided. The lubricating oil composition of the present invention obtained by blending this additive with a base oil is particularly preferable as a lubricating oil composition used for automatic transmission oil and continuously variable transmission oil.

Hereinafter, embodiments of the lubricating oil additive of the present invention and a lubricating oil composition obtained by blending it with a base oil will be described in detail.
The lubricating oil additive of the present invention comprises a reaction product of (A) succinimide, (B) a phenol represented by the following formula (1), and (C) an aldehyde or ketone represented by the following formula (2). It is a thing.

（式中、Ｒは水素または炭素数１〜８の炭化水素基を示し、xは１または２である。）

(In the formula, R represents hydrogen or a hydrocarbon group having 1 to 8 carbon atoms, and x is 1 or 2.)

（式中、Ｒ^１、Ｒ^２はそれぞれ水素または炭素数１〜２０の炭化水素基を示す。）

(In the formula, R ¹ and R ² each represent hydrogen or a hydrocarbon group having 1 to 20 carbon atoms.)

Here, the succinimide as component (A) is preferably alkyl or alkenyl succinimide, and is obtained from (a) alkenyl or alkyl succinic acid (anhydride) and (b) amine by a known method. be able to.
Examples of the alkenyl group or alkyl group constituting the component (a) include hydrocarbon groups having 5 to 350 carbon atoms. This component (a) is composed of a polymer or copolymer such as ethylene, propylene, butene, butadiene, decene, hexadecene and the like having a carbon number of 2 to about 20, such as monoolefin and diolefin, or a mixture thereof and maleic acid or maleic anhydride. It is derived from an acid and can be produced by a known method.

As the component (b) amine, for example, ethylenediamine, propanediamine, butanediamine, N-methyl-1,3-propanediamine, alkylenediamine such as N, N-dimethyl-1,3-propanediamine, or diethylenetriamine, Examples include polyalkylene polyamines such as triethylenetetramine, aminoethylpiperazine, and tetraethylenepentamine.
The succinimide as component (A) produced from (a) alkenyl or alkyl succinic acid (anhydride) and (b) amine may be modified by a known method with boron or the like. It does not have to be.

(B) As phenols of a component, alkylphenol is preferable. The alkylphenol may be monoalkylphenol or dialkylphenol, but monoalkylphenol is preferred from the viewpoint of sure reaction.
Examples of the alkyl group include those having 1 to 8 carbon atoms, and examples thereof include an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t-butyl group, a heptyl group, and an octyl group. (B) As a component, since the static friction coefficient of lubricating oil can be made high, the monoalkylphenol whose carbon number of a phenol or an alkyl group is 1-4 is used preferably.

The aldehyde or ketone of component (C) has the structure shown in the above formula (2). In this formula, R ¹ and R ² are each hydrogen or a hydrocarbon group having 1 to 20 carbon atoms. The number of carbon atoms of the hydrocarbon group is preferably 1 to 10 from the viewpoint of reliably reacting. For example, the hydrocarbon group is an alkyl group, an aralkyl group, a cycloalkyl group, an aryl group, an alkaryl group, an alkenyl group, or an alkynyl group. R ¹ and R ² may be inertly substituted. When R ¹ and R ² are alkyl groups, examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, pentyl, octyl, decyl, octadecyl and the like. When R ¹ and R ² are an aralkyl group, examples thereof include benzyl and β-phenylethyl. When R ¹ and R ² are cycloalkyl groups, for example, cyclohexyl, cycloheptyl, cyclooctyl, 2-methylcyclohexyl, 2-methylcycloheptyl, 3-butylcyclohexyl and the like. When R ¹ and R ² are aryl groups, for example, phenyl, naphthyl and the like. When R ¹ and R ² are alkaryl groups, for example, vinyl, allyl, 1-butenyl and the like. When R ¹ and R ² are alkynyl groups, for example, ethynyl, propynyl, butynyl and the like.
The aldehyde or ketone preferably used is specifically formaldehyde, paraformaldehyde, ethanal, propanal, butanal, acetone, methyl ethyl ketone, diethyl ketone, etc., but more preferably an aldehyde in which either R ¹ or R ² is hydrogen. preferable. In particular, formaldehyde is most preferably used because the reaction proceeds easily.

  The lubricating oil additive of the present invention is a reaction product obtained by reacting the components (A) to (C) described above. When producing such a lubricating oil additive, from the viewpoint of easy handling of the additive, the molar charge ratio of the components (A) to (C) is (A) :( B) :( C) = A ratio of 1: 1 to 10: 1 to 10 is preferable, and a ratio of 1: 1 to 6: 1 to 6 is more preferable. This is because when the number of carbon atoms in the alkyl group of the alkylphenol is small, if the proportion of the component (B) and the component (C) is too large, the fluidity may be deteriorated. The reaction is preferably performed at a temperature of 20 to 200 ° C, preferably 50 to 150 ° C.

The lubricating oil composition of the present invention comprises a base oil blended with the above-described lubricating oil additive of the present invention (succinimide derivative which is a reaction product comprising the components (A) to (C)). The content of this succinimide derivative is preferably in the range of 0.01 to 50% by mass, more preferably in the range of 0.1 to 20% by mass from the viewpoint of effectively exhibiting the above-described effects.
As the base oil, either mineral oil or synthetic oil can be used. Here, 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.

As the synthetic oil, various conventionally known oils can be used. For example, poly α-olefin (including α-olefin copolymer), polybutene, polyol ester, dibasic acid ester, phosphate ester, polyphenyl ether, alkylbenzene, alkylnaphthalene, polyoxyalkylene glycol, neopentyl glycol, silicone Oil, trimethylolpropane, pentaerythritol, hindered ester and the like can be used.
These base oils can be used alone or in combination of two or more kinds, and mineral oil and synthetic oil may be used in combination.

As said base oil, it is preferable that dynamic viscosity in 100 degreeC is 1-30 mm < ² > / s. When the kinematic viscosity is in the above range, friction at sliding parts such as gear bearings and clutches of the automatic transmission can be sufficiently reduced and the low temperature characteristics are also improved. Kinematic viscosity is more preferably 2 to 20 mm ² / s at 100 ° C., particularly preferably 3 to 10 mm ² / s. If this kinematic viscosity exceeds 30 mm ² / s, the fuel efficiency deteriorates and the low temperature viscosity becomes too high. On the other hand, if the kinematic viscosity is less than 1 mm ² / s, the lubrication performance deteriorates due to increased wear at sliding parts such as gear bearings and clutches of automatic transmissions, and evaporability increases, resulting in increased consumption of lubricating oil. May increase.
Also, C _A is preferably not more than 20% of the base oil, or more preferably 10% or less. % Low-temperature characteristics will be good if _{C A} is 20% or less.

In the lubricating oil composition of the present invention, an ashless dispersant other than the lubricating oil additive of the present invention, a metallic detergent, a friction modifier, a viscosity index improver, if necessary, for the purpose of further improving its performance. Various additives typified by extreme pressure additives, antioxidants, corrosion inhibitors, antifoaming agents, colorants, etc. may be added to the base oil alone or in combination of several kinds. Oil additives do not interfere with these effects.
Examples of the antioxidant include amine-based antioxidants such as alkylated diphenylamine, phenyl-α-naphthylamine, alkylated-α-naphthylamine, 2,6-di-t-butyl-4-methylphenol, 4,4 ′. -Phenolic antioxidants such as -methylenebis (2,6-di-t-butylphenol) are used, and these are usually used at a ratio of 0.05 to 5% by mass.

  Friction preparation agents include fatty acid esters, fatty acid amides, phosphorus compounds such as phosphate esters, phosphite esters, and thiophosphate esters, organic molybdenum compounds such as MoDTP and MoDTC, organic zinc compounds such as ZnDTP, and alkyl mercaptyl. Examples thereof include organic boron compounds such as borates, solid lubricant friction preparation agents such as graphite, molybdenum disulfide, antimony sulfide, boron compounds, and polytetrafluoroethylene. These are usually 0.1 to 10% by mass. Used at a rate of

Examples of the metal detergent include calcium sulfonate, magnesium sulfonate, barium sulfonate, calcium salicylate, magnesium salicylate, calcium phenate, barium phenate, etc., and these are usually 0.1 to 10 mass. Used in percentages.
Examples of the viscosity index improver include polymethacrylate-based, polyisobutylene-based, ethylene-propylene copolymer system, styrene-butadiene hydrogenated copolymer system, etc., and these are usually 0.5 to 35% by mass. Used in proportions.
The various additives as described above may be blended alone or in combination, and the lubricating oil additive of the present invention does not inhibit these effects.

  Since the lubricating oil composition of the present invention thus prepared has a high coefficient of static friction (high wet friction material torque capacity), it is suitable as an automatic transmission oil or a continuously variable transmission oil. Further, it can be used as a lubricating oil for construction machines, agricultural machines, manual transmissions, two-wheeled gasoline engines, diesel engines, gas engines, shock absorber oils, etc., equipped with transmissions having wet clutches and wet brakes.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples. Specifically, as shown below, after each additive was prepared (manufactured) and blended with the base oil, a simple evaluation for measuring the friction coefficient was performed (Examples 1 to 6, Comparative Examples 1 to 6). 3). Furthermore, a lubricating oil composition was prepared by blending assuming an actual transmission oil formulation and evaluated for practical use (Example 7, Comparative Example 4).

[Examples 1-6, Comparative Examples 1-3: Simple evaluation]
The manufacturing method of the additive used by the Example and the comparative example is shown below.
<Manufacture of lubricating oil additive a>
In a 200 ml separable flask, 0.03 mol of polyisobutenyl succinimide (monotype, polyisobutenyl group has an average molecular weight of 960), 0.09 mol of phenol, and 0.1 mol of formaldehyde were added. The reaction was carried out at 5 ° C. for 5 hours. Next, unreacted formaldehyde and produced water were removed under reduced pressure to obtain a lubricating oil additive a as a reaction product. The infrared absorption spectrum of the additive a is shown in FIG.

<Manufacture of lubricating oil additive b>
In a 200 ml separable flask, 0.03 mol of polyisobutenyl succinimide (monotype, polyisobutenyl group has an average molecular weight of 960), 0.03 mol of phenol, and 0.03 mol of formaldehyde were added. The reaction was carried out at 5 ° C. for 5 hours. Next, unreacted formaldehyde and produced water were removed under reduced pressure to obtain a lubricating oil additive b as a reaction product. The infrared absorption spectrum of the additive b is shown in FIG.

<Manufacture of lubricating oil additive c>
In a 200 ml separable flask, 0.03 mol of polyisobutenyl succinimide (monotype, polyisobutenyl group has an average molecular weight of 960), 0.15 mol of phenol, and 0.17 mol of formaldehyde were added. The reaction was carried out at 5 ° C. for 5 hours. Next, unreacted formaldehyde and produced water were removed under reduced pressure to obtain a lubricating oil additive c as a reaction product. An infrared absorption spectrum of the additive c is shown in FIG.

<Manufacture of lubricating oil additive d>
In a 200 ml separable flask, 0.03 mol of polyisobutenyl succinimide (monotype, average molecular weight of polyisobutenyl group is 960), 0.09 mol of 4-ethylphenol, and 0.1 mol of formaldehyde were added. And reacted at 110 ° C. for 5 hours. Next, unreacted formaldehyde and produced water were removed under reduced pressure to obtain a lubricating oil additive d as a reaction product. An infrared absorption spectrum of the additive d is shown in FIG.

<Manufacture of lubricating oil additive e>
In a 200 ml separable flask, 0.03 mol of polyisobutenyl succinimide (monotype, polyisobutenyl group has an average molecular weight of 960), 0.09 mol of 4-isopropylphenol, and 0.1 mol of formaldehyde were added. And reacted at 110 ° C. for 5 hours. Next, unreacted formaldehyde and produced water were removed under reduced pressure to obtain a lubricating oil additive e as a reaction product. An infrared absorption spectrum of the additive e is shown in FIG.

<Manufacture of lubricating oil additive f>
In a 200 ml separable flask, 0.03 mol of polyisobutenyl succinimide (monotype, polyisobutenyl group has an average molecular weight of 960), 0.09 mol of 4-t-butylphenol, and 0.1 mol of formaldehyde And reacted at 110 ° C. for 5 hours. Next, unreacted formaldehyde and produced water were removed under reduced pressure to obtain a lubricating oil additive f as a reaction product. An infrared absorption spectrum of the additive f is shown in FIG.

<Manufacture of lubricating oil additive g>
In a 200 ml separable flask, 0.03 mol of polyisobutenyl succinimide (monotype, polyisobutenyl group has an average molecular weight of 960), 0.09 mol of 4-nonylphenol and 0.1 mol of formaldehyde were added. The reaction was carried out at 5 ° C. for 5 hours. Next, unreacted formaldehyde and produced water were removed under reduced pressure to obtain a lubricating oil additive g as a reaction product. The infrared absorption spectrum of the additive g is shown in FIG.

<Preparation of lubricating oil composition>
A mineral oil of 150 neutral fraction (100 ° C. kinematic viscosity 5.2 mm ² / s) was used as the base oil, and additives a to f obtained by the above production method were used, and the nitrogen amount derived from the additive was 1500 mass ppm. A lubricating oil composition was prepared by blending so as to be (Examples 1 to 6). In Comparative Example 1, no additive is blended with only the base oil, and in Comparative Example 2, non-boronated succinic monoimide having a molecular weight of about 2000 is blended as an additive under the same conditions as in Examples. Comparative Example 3 Then, the above-mentioned additive g was mix | blended on the conditions similar to an Example. These compounding formulations are shown in Table 1.

<Slip test>
Using a low-speed slip tester, the test was performed under the following conditions, and the friction coefficient (μ2) at 2 rpm and the ratio (μ ratio, μ2 / μ300) between the friction coefficient (μ300) at μ2 and 300 rpm were obtained. . Table 1 shows the results. FIG. 8 shows a graph plotting μ2 against μ ratio.
-Friction material: Commercially available cellulose-based wet paper material, steel plate-Test temperature: 120 ° C
・ Surface pressure: 1.22 MPa
・ Measurement: 1 to 300 rpm, step

[Simple evaluation results]
From the results of Table 1, in the systems using the lubricating oil compositions of Examples 1 to 6, the value of μ2, which can be said to be substantially the static friction coefficient, is high (the wet friction material has a high torque capacity). Recognize. In addition, as easily understood from the μ2 · μ ratio plot of FIG. 8, the plots of the lubricating oil compositions of Examples 1 to 6 are a plot (comparative example 1) in which 150 neutral mineral oil was evaluated, and the conventional technique. It is above the straight line connecting the plot (Comparative Example 2) for evaluating a certain non-boronated succinic monoimide, and μ2 with respect to μ ratio is high. Therefore, it can be understood that the lubricating oil composition of the present invention exhibits excellent performance particularly as a transmission lubricating oil.

[Example 7, Comparative Example 4: Practical evaluation]
In addition to the above evaluation, the lubricating oil composition prepared assuming an actual additive formulation was also evaluated.
As the base oil, a mixed oil of mineral oil of 100 neutral fraction (100 ° C. kinematic viscosity 4.1 mm ² / s) and 60 neutral fraction mineral oil (100 ° C. kinematic viscosity 2.7 mm ² / s) was used. Next, in the additive formulation of Example 7, the additive a used in Example 1 was blended with the base oil (40 ° C. kinematic viscosity 26.05 mm ² / s, 100 ° C. kinematic viscosity 5.468 mm ² / s. ). In the additive formulation of Comparative Example 4, additive a was not blended (40 ° C. kinematic viscosity 26.62 mm ² / s, 100 ° C. kinematic viscosity 5.493 mm ² / s). As a practical evaluation, the performance of each lubricating oil composition as a lubricating oil for transmissions was evaluated by the following method. Table 2 shows the base oil, additive formulation and evaluation results.

<Performance evaluation method>
Using a SAE No.2 testing machine, measure the static friction coefficient (μs) at static and the dynamic friction coefficient (μd at 1200 rpm) under dynamic conditions under the test conditions shown below to obtain the static friction coefficient (μ0). It was. The performance was evaluated based on the average value of μs value and μ ratio value from 500 cycles to 5000 cycles. A higher μs value indicates a higher torque capacity. A μ ratio (μ0 / μd) is acceptable if it is 1.02 or less. The evaluation results are shown in Table 2.
-Friction material: Commercially available cellulose-based wet paper material, steel plate-Test temperature: 100 ° C
・ Surface pressure: 1.22 MPa
・ Dynamic rotation speed: 2260 rpm
・ Static rotation speed: 0.7rpm
・ Inertia: 0.343kg ・ m ²

[Results of practical evaluation]
The lubricating oil composition of Example 7 had higher μs and better μ ratio and μd value than the lubricating oil composition of Comparative Example 4. Therefore, it can be seen that the lubricating oil composition of Example 7 containing additive a has excellent μs improvement performance as an automatic transmission oil.

  The lubricating oil composition using the lubricating oil additive of the present invention can be suitably used as an automatic transmission oil or a continuous transmission oil that requires a high coefficient of static friction.

The infrared absorption spectrum of the additive a in an Example. The infrared absorption spectrum of the additive b in an Example. The infrared absorption spectrum of the additive c in an Example. The infrared absorption spectrum of the additive d in an Example. The infrared absorption spectrum of the additive e in an Example. The infrared absorption spectrum of the additive f in an Example. The infrared absorption spectrum of the additive g in an Example. In the Examples, a graph plotting μ2 against μ ratio.

Claims (8)

Lubricant characterized by being a reaction product of (A) succinimide, (B) phenol represented by the following formula (1), and (C) aldehyde or ketone represented by the following formula (2) Oil additive.

(In the formula, R represents hydrogen or a hydrocarbon group having 1 to 8 carbon atoms, and x is 1 or 2.)

(In the formula, R ¹ and R ² each represent hydrogen or a hydrocarbon group having 1 to 20 carbon atoms.) The lubricating oil additive according to claim 1,
A lubricating oil additive, wherein x in the formula (1) is 1. The lubricating oil additive according to claim 1 or claim 2,
A lubricating oil additive, wherein either R ¹ or R ² in the formula (2) is hydrogen. In the lubricating oil additive according to any one of claims 1 to 3,
When producing the reaction product, the molar charge ratio of the components (A) to (C) is a ratio of (A) :( B) :( C) = 1: 1 to 10: 1-10. Lubricating oil additive characterized by   A lubricating oil composition comprising the base oil blended with the lubricating oil additive according to any one of claims 1 to 4.   The lubricating oil composition according to claim 5, wherein the lubricating oil composition is used for a transmission.   The lubricating oil composition according to claim 6, wherein the lubricating oil composition is for a transmission having a wet clutch or a wet brake.   The lubricating oil composition according to any one of claims 5 to 7, wherein the lubricating oil composition is an automatic transmission oil or a continuously variable transmission oil.

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