JP2018135409A - A friction modifier for lubricant and lubricant composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the friction modifier for a lubricant and the lubricant composition that have improved friction reducing action.SOLUTION: The friction modifier for a lubricant blended with base oil of the lubricant composition comprises a compound composed of a linear chain part comprising a linear saturated hydrocarbon and a terminal part which is bonded to a carbon atom located at an end of the linear chain part and has a plurality of hydroxy groups. The terminal part preferably has two hydroxy groups. Also, the compound is preferably n-alkyl-1,2-diol having 12 to 18 carbon atoms. Further, the compound has more preferably 16 or more to 18 or less carbon atoms.SELECTED DRAWING: None

Description

  The present invention relates to a friction modifier for lubricating oil and a lubricating oil composition.

  In automobiles, lubricating oil is supplied to engines and transmissions. Such a lubricating oil is produced by blending various additives with the base oil. For example, Patent Document 1 discloses, as an additive, a friction modifier (FM) agent that improves a friction reducing action that reduces frictional resistance in a sliding portion.

JP2015-36412A

  In a large vehicle such as a cargo vehicle, compared with a general passenger vehicle, the engine output is high, so that the frictional resistance generated in the sliding portion is large. For this reason, the friction modifier described above is required to further improve the friction reducing action in order to reduce fuel consumption. Such a demand is common not only to large vehicles but also to vehicles that use lubricating oil.

  An object of the present invention is to provide a friction modifier for lubricating oil and a lubricating oil composition having an improved friction reducing effect.

  A friction modifier for lubricating oil that solves the above-mentioned problem is a linear part composed of a linear saturated hydrocarbon and a terminal part bonded to a carbon atom located at the terminal of the linear part, and has a plurality of hydroxy groups. And a compound composed of the terminal portion.

A lubricating oil composition that solves the above problems is a lubricating oil composition comprising a base oil and a friction modifier, wherein the friction modifier comprises a linear portion composed of a linear saturated hydrocarbon and the linear chain. A friction modifier for lubricating oil comprising a compound composed of a terminal portion bonded to a carbon atom located at the terminal of the portion and the terminal portion having a plurality of hydroxy groups.
According to the friction modifier for lubricating oil and the lubricating oil composition having the above-described configuration, the friction reducing effect can be improved.

  In the friction modifier for lubricating oil, it is preferable that the terminal portion has two hydroxy groups. According to the said structure, the improvement of a friction reduction effect | action can be effectively acquired because a terminal part has two hydroxy groups.

  In the friction modifier for lubricating oil, the compound is preferably an n-alkyl-1,2-diol having 12 to 18 carbon atoms in the compound. According to the said structure, the friction reduction effect | action by the friction modifier for lubricating oil can be obtained effectively.

  In the friction modifier for lubricating oil, the compound preferably has 16 to 18 carbon atoms in the compound. According to the said structure, the friction reduction effect | action by the friction regulator for lubricating oil can be obtained more effectively.

(A) is a perspective view which shows schematic structure of the test which measures a friction coefficient, (b) is a side view which shows schematic structure of the test which measures a friction coefficient.

Hereinafter, one embodiment of a friction modifier for lubricating oil and a lubricating oil composition will be described.
(Friction modifier for lubrication)
The friction modifier for lubricating oil includes a straight chain portion (n-alkyl portion) composed of a straight chain saturated hydrocarbon and a terminal portion bonded to a carbon atom located at one end of the straight chain portion, and a plurality of hydroxy groups. And a compound composed of a terminal moiety having a group (—OH). The number of carbon atoms in this compound is 12 or more, preferably 12 or more and 18 or less, more preferably 16 or more and 18 or less. Moreover, the carbon atom number in the linear part of a compound is 10 or more, Preferably it is 10 or more and 16 or less, More preferably, it is 14 or more and 16 or less. When the number of carbon atoms in the straight chain portion is 10 or more, the compound adsorbed on the sliding portion easily exhibits a friction reducing action. In addition, when the number of carbon atoms in the straight chain portion is 18 or less, the lubricating oil composition can easily be mixed with the base oil, and when the number of carbon atoms in the straight chain portion is 16 or less, the lubricating oil composition It becomes easy to ensure the mixing property with respect to the base oil.

  The terminal portion having a plurality of hydroxy groups has, for example, a polyhydric alcohol structure, and preferably has a divalent alcohol structure. Examples of the divalent alcohol include vicinal diol (1,2-diol) in which one hydroxy group is bonded to each of two adjacent carbon atoms as shown in chemical formula (1). Moreover, as a terminal part which has two hydroxy groups, you may have a structure in which some hydroxy groups of the polyhydric alcohol were esterified. Examples include monoglycerides represented by chemical formula (2). Moreover, as a terminal part which has two hydroxyl groups, you may have a structure in which some hydroxy groups of the polyhydric alcohol were etherified. Examples include monoglycerol ether represented by chemical formula (3). When the terminal portion has two hydroxy groups, it becomes easy to ensure affinity for the metal surface, and the degree of freedom for the material when producing the friction modifier for lubricating oil is improved. In the following chemical formulas (1) to (3), “R” represents a straight chain portion composed of a straight chain saturated hydrocarbon.

(Lubricating oil composition)
The lubricating oil composition is produced by blending the above-described friction modifier for lubricating oil with the base oil. As the base oil, petroleum-based lubricating base oil can be used. A petroleum-based lubricating base oil is produced by refining a vacuum distillation fraction of a residual oil obtained by distilling crude oil under normal pressure by a solvent refining method, a hydrotreating method, a sulfuric acid washing method or the like. Examples of the composition of such base oil include paraffinic, naphthenic, and aromatic types, and paraffinic types are preferred.

  In addition, synthetic oil can be used as the base oil. Synthetic oils include, for example, hydrocarbon synthetic oils such as α-olefin oligomers and alkylbenzenes, ester synthetic oils such as diesters and polyol esters, ether synthetic oils such as phenyl ether, and fluorine compounds. Synthetic oil, silicone oil, etc. are mentioned.

  In addition, the base oil may be a mixture of the above-described plurality of petroleum-based lubricating base oils, or a mixture of the above-described plurality of synthetic oils. Good. Further, the base oil may be one in which one or more petroleum-based lubricating base oils and one or more synthetic oils are selectively mixed.

  In the lubricating oil composition, the concentration of the above-described compound is preferably 2500 ppm or more and 10,000 ppm or less, and more preferably 5000 ppm or more and 10,000 ppm or less. More preferably, it is 7500 ppm or more and 10,000 ppm or less. According to such a configuration, it is possible to reduce the manufacturing cost of the friction adjusting agent for lubricating oil while obtaining the friction reducing action by the friction adjusting agent for lubricating oil. The lubricating oil composition may contain other lubricating oil additives such as viscosity index improvers, antifoaming agents, antioxidants, pour point depressants, etc., in addition to the above-described friction modifier for lubricating oil. Is possible.

  Next, examples of the lubricating oil composition described above will be described. The present inventors used Cosmo Neutral 100 (manufactured by Cosmo Oil Lubricants Co., Ltd.) as a base oil of the lubricating oil composition, which is classified into Group 2 according to the base oil classification in the American Petroleum Institute (API). A plurality of test oils were produced by blending various friction modifiers with the base oil, and a test for measuring a friction coefficient when these test oils were used as a lubricating oil composition was conducted.

(Summary of study)
As shown in FIGS. 1A and 1B, in the test for measuring the friction coefficient, the lower test piece 11 and the upper test piece 12 were used. The lower test piece 11 is a metal having a rectangular parallelepiped shape, and is specifically SUJ2 (JISG4805: high carbon chrome bearing steel). The upper test piece 12 is a metal having a cylindrical shape, and is specifically SUJ2 (JISG4805: high carbon chrome bearing steel). While maintaining the state in which the peripheral surface 12a of the upper test piece 12 is pressed against the upper surface 11a of the lower test piece 11 with a vertical load F, the test oil is supplied to the contact portion with the amplitude A and the reciprocating speed Vf. Reciprocated. This test was performed using UMT-Tribolab manufactured by Bruker, and the average value of the measured values was calculated as the friction coefficient μ. Evaluation of the test oil showed a reduction rate of 10% or more at the load F = 200N, 300N, 400N under the following load conditions with respect to the friction coefficient μ of Comparative Example 1 which is a base oil to which no friction modifier is added. Test oil was good. Specific test conditions are as follows.

・ Lower specimen 11
Arithmetic mean roughness Ra of the upper surface 11a: 0.02
-Upper test piece 12
Diameter D: 10mm
Length L: 12.75mm
Arithmetic average roughness Ra of peripheral surface 12a: 0.02
・ Amplitude A: 1.5mm
・ Reciprocating speed Vf: 50Hz
Test temperature T: 100 ° C
-Load conditions: After running for 30 seconds at load F = 50N, load F = 100N for 5 minutes, load F = 200N for 5 minutes, load F = 300N for 5 minutes, load F = 400N for 5 minutes Finally, it was operated at a load F = 100 N for 5 minutes.

(Test 1)
In Test 1, the test oil of Comparative Example 2 is a blend of butyl stearate, which is an ester, with the base oil as a friction modifier at a concentration of 7500 ppm. The test oil of Comparative Example 3 is a blend of 1-hexadecanol classified as a monohydric alcohol with respect to the base oil at a concentration of 7500 ppm as a friction modifier. The test oil of Comparative Example 4 is a blend of glycerol tristearate classified as a triglyceride with a base oil at a concentration of 7500 ppm as a friction modifier. The test oil of Example 1 is a blend of 1,2-hexadecanediol, which is classified into vicinal diol, which is a divalent alcohol, with respect to the base oil at a concentration of 7500 ppm as a friction modifier. 1,2-hexadecanediol is an n-alkyl-1,2-diol having 16 carbon atoms in the compound and 14 carbon atoms in the straight chain portion. The test oil of Example 2 is obtained by blending glycerol monostearate classified as a monoglyceride having two hydroxy groups in the terminal portion with a base oil at a concentration of 7500 ppm as a friction modifier. Glycerol monostearate has 21 carbon atoms in the compound and 18 carbon atoms in the straight chain portion. The test oil of Example 3 is obtained by blending glycerol α-monostearyl classified as monoglycerol ether having two hydroxy groups at the terminal portion with a base oil at a concentration of 7500 ppm as a friction modifier. Glycerol α-monostearyl has 21 carbon atoms in the compound and 18 carbon atoms in the straight chain portion.

  Table 1 shows an example of Test 1 results. In Table 1, μ represents a friction coefficient that is an average value of measured values, and σ represents a standard deviation of measured values.

  As shown in Table 1, each friction coefficient μ of Comparative Examples 2, 3, and 4 was found to have a reduction rate of less than 10% with respect to the friction coefficient μ of Comparative Example 1 under all load conditions. On the other hand, each friction coefficient μ of Examples 1, 2, and 3 was found to have a reduction rate of 10% or more with respect to the friction coefficient μ of Comparative Example 1 under all load conditions. That is, it was recognized that the friction reducing effect was improved by blending a compound having two hydroxy groups at the terminal portion bonded to the linear portion with the base oil as a friction modifier.

(Test 2)
In Test 2, the test oil of Comparative Example 5 has a concentration of 7500 ppm of 1,2-decanediol having 10 carbon atoms in the compound and 8 carbon atoms in the straight chain portion relative to the base oil. It is a blend. The test oil of Example 4 is a blend of 1,2-dodecanediol having 12 carbon atoms in the compound and 10 carbon atoms in the linear portion at a concentration of 7500 ppm with respect to the base oil. is there. The test oil of Example 5 is a blend of 1,2-tetradecanediol having 14 carbon atoms and 12 carbon atoms in the straight chain portion at a concentration of 7500 ppm with respect to the base oil. is there. The test oil of Example 6 is a blend of 1,2-hexadecanediol having a carbon atom number of 16 in the compound and 14 carbon atoms in the straight chain portion at a concentration of 7500 ppm with respect to the base oil. is there. The test oil of Example 7 is a blend of 1,2-octadecanediol having a carbon atom number of 18 in the compound and 16 carbon atoms in the straight chain portion at a concentration of 7500 ppm with respect to the base oil. is there. Table 2 shows an example of the results of Test 2. In addition, the test oil of Example 6 is the same test oil as the test oil of Example 1.

  As shown in Table 2, the friction coefficient μ of Comparative Example 5 is lower than the friction coefficient μ of Comparative Example 1 under all load conditions, but the reduction rate is 10% under some load conditions (300N, 400N). Was found to be less than. On the other hand, each friction coefficient μ of Examples 4 to 7 was found to have a reduction rate of 10% or more with respect to the friction coefficient μ of Comparative Example 1 under all load conditions. That is, when the compound contained in the friction modifier is n-alkyl-1,2-diol in which carbon atoms are linearly linked, it is recognized that the number of carbon atoms in the compound is preferably 12 or more and 18 or less. It was. In addition, the number of carbon atoms in the compound is preferably 16 or more and 18 or less from the viewpoint that a reduction rate of 14% or more is obtained with respect to the friction coefficient μ of Comparative Example 1 at loads F = 200N, 300N, and 400N. Was recognized.

(Test 3)
In Test 3, the test oil of Comparative Example 6 is an n-alkyl-1,2-diol having 16 carbon atoms in the compound and 14 carbon atoms in the straight chain portion relative to the base oil. , 2-hexadecanediol is blended at a concentration of 100 ppm as a friction modifier. The test oil of Example 8 is a blend of 1,2-hexadecanediol as a friction modifier at a concentration of 1000 ppm with respect to the base oil. The test oil of Example 9 is a blend of 1,2-hexadecanediol as a friction modifier at a concentration of 2500 ppm with respect to the base oil. The test oil of Example 10 is a blend of 1,2-hexadecanediol as a friction modifier at a concentration of 5000 ppm with respect to the base oil. The test oil of Example 11 is a blend of 1,2-hexadecanediol as a friction modifier at a concentration of 7500 ppm with respect to the base oil. The test oil of Example 12 is a blend of 1,2-hexadecanediol at a concentration of 10,000 ppm with respect to the base oil. Table 3 shows an example of the test 3 result.

  As shown in Table 3, each friction coefficient μ of Comparative Example 6 is lower than that of Comparative Example 1 under all load conditions, but the reduction rate with respect to the friction coefficient μ of Comparative Example 1 is under all load conditions. It was found to be less than 10%. Moreover, it was recognized that each friction coefficient μ of Examples 8 to 12 has a reduction rate of 10% or more with respect to the friction coefficient μ of Comparative Example 1 under all load conditions. That is, when 1,2-hexadecanediol was blended as a friction modifier, it was confirmed that the concentration of the friction modifier in the lubricating oil composition was preferably 1000 ppm or more and 10,000 ppm or less. Moreover, it is preferable that the density | concentration of a friction modifier is 2500 ppm or more and 10000 ppm or less from a viewpoint that the reduction rate of 12.5% or more is obtained on all the load conditions. Further, from the viewpoint that a reduction rate of 13% or more can be obtained under all load conditions, it is preferably 5000 ppm or more and 10,000 ppm or less, and from the viewpoint that a reduction rate of 15% or more can be obtained under all load conditions, 7500 ppm or more. It is preferable that it is 10,000 ppm or less.

(Test 4)
In Test 4, the test oil of Comparative Example 7 was 1000 ppm of glycerol monostearate having 21 carbon atoms in the compound and 18 carbon atoms in the straight chain portion as a friction modifier with respect to the base oil. It is blended by concentration. The test oil of Comparative Example 8 is obtained by blending glycerol monostearate with a base oil at a concentration of 2500 ppm as a friction modifier. The test oil of Example 13 is obtained by blending glycerol monostearate with a base oil at a concentration of 5000 ppm as a friction modifier. The test oil of Example 14 is obtained by blending glycerol monostearate with a base oil at a concentration of 7500 ppm as a friction modifier. The test oil of Example 15 is obtained by blending glycerol monostearate with a base oil at a concentration of 10,000 ppm as a friction modifier. Table 4 shows an example of the result of Test 4. In addition, the test oil of Example 14 and the test oil of Example 2 are the same test oil.

  As shown in Table 4, the friction coefficient μ in Comparative Examples 7 and 8 was found to have a reduction rate of less than 10% with respect to the friction coefficient μ in Comparative Example 1 except when the load condition was 200N. On the other hand, each friction coefficient μ in Examples 13, 14, and 15 was found to have a reduction rate of 10% or more with respect to the friction coefficient μ in Comparative Example 1 at loads F = 200N, 300N, and 400N. That is, it was confirmed that the concentration of the friction modifier in the lubricating oil composition is preferably 5000 ppm or more and 10,000 ppm or less when glycerol monostearate is blended as a friction modifier. Further, the concentration of the friction modifier is preferably 7500 ppm or more and 10,000 ppm or less from the viewpoint that a reduction rate of 15% or more is obtained with respect to the friction coefficient μ of Comparative Example 1 at the load F = 200N, 300N, 400N. .

According to the friction modifier for lubricating oil and the lubricating oil composition of the above embodiment, the following effects can be obtained.
(1) The above-described friction modifier for lubricating oil includes a linear portion composed of a linear saturated hydrocarbon and a terminal portion bonded to a carbon atom located at one end of the linear portion, and a plurality of hydroxy groups And a compound composed of a terminal moiety having a group. According to such a friction modifier for lubricating oil, it is possible to improve the friction reducing action in the lubricating oil composition by being blended with the base oil.

  (2) In the friction modifier for lubricating oil, it is possible to effectively improve the friction reducing action of the lubricating oil composition by having two hydroxy groups at the end portion, that is, having a divalent alcohol structure. It is.

  (3) When the compound contained in the friction modifier for lubricating oil is an n-alkyl-1,2-diol having 12 to 18 carbon atoms, it is possible to effectively obtain a friction reducing action. .

  (4) Since the compound contained in the friction modifier for lubricating oil is an n-alkyl-1,2-diol having 16 to 18 carbon atoms, it is possible to more effectively obtain a friction reducing action. is there.

  (5) In a large vehicle such as a cargo vehicle, the engine output is large and the frictional resistance generated in the sliding portion is larger than that of a general passenger car. Therefore, when the load F is large, a friction reducing action can be effectively obtained. It is preferable. From these facts, the concentration of the friction modifier for lubricating oil in the lubricating oil composition is preferably 5000 ppm or more and 10,000 ppm or less, and more preferably 7500 ppm or more and 10,000 ppm or less. Thereby, it is possible to effectively obtain a friction reducing action.

In addition, the said embodiment can also be suitably changed and implemented as follows.
The test for measuring the friction coefficient μ can be performed under the same conditions not in the UMT-Trilabab manufactured by Bruker but in the SRV tester manufactured by OPTIMOL.

  In the friction modifier for lubricating oil, in the straight chain portion, an arbitrary hydrogen atom may be substituted with, for example, an alkanyl group, an alkenyl group, or an alkynyl group. Moreover, the linear part may have an unsaturated part depending on the case.

-Lubricating oil composition may be applied not only to a large vehicle but a general passenger car.
The terminal portion having a divalent alcohol structure may be geminal diol (1,1-diol) in which two hydroxy groups are bonded to a common carbon atom as shown in chemical formula (4). .

  DESCRIPTION OF SYMBOLS 11 ... Lower test piece, 11a ... Upper surface, 12 ... Upper test piece, 12a ... Peripheral surface.

Claims (5)

A compound composed of a straight-chain portion composed of a straight-chain saturated hydrocarbon and a terminal portion bonded to a carbon atom located at the end of the straight-chain portion, the terminal portion having a plurality of hydroxy groups Friction modifier for lubricating oil. The friction modifier for lubricating oil according to claim 1, wherein the terminal portion has two hydroxy groups. The friction modifier for lubricating oil according to claim 1 or 2, wherein the compound is an n-alkyl-1,2-diol having 12 to 18 carbon atoms in the compound. The friction modifier for lubricating oil according to claim 3, wherein the compound has 16 to 18 carbon atoms in the compound. A lubricating oil composition comprising a base oil and a friction modifier,
The friction modifier is composed of a linear portion composed of a linear saturated hydrocarbon, and a terminal portion bonded to a carbon atom located at the terminal of the linear portion and having a plurality of hydroxy groups. A lubricating oil composition, which is a friction modifier for lubricating oils containing the prepared compound.