KR900005103B1 - Lubricant oil composition - Google Patents

Abstract

A lubricating oil compsn. comprises mineral oil contg. 0.5 wt.% or less of sulphur, 0.05-5 wt.% of alkenyl succinic acid ester and/or alkyl succinic acid ester, and 0.005-5 wt.% of fatty acid ester of multivalent alcohol. The mineral oil has 1.5-30 cS of kinematic viscosity at 100 deg. C and -15 deg. C or less of pour point. The compsn. is used for wet brakes, wet cluches, automatic transmission components and tractors.

Description

Lubricant composition

1 and 3 are graphs showing changes over time of μ ₀ / μ ₁₂₀₀ at each time up to 2000 cycles in Examples and Comparative Examples.

2 is a graph showing the temperature change.

The present invention relates to a lubricating oil composition, and more particularly, to a lubricating oil composition which can be suitably used for lubricating a portion including a wet clutch or a wet brake such as an automatic transmission or a tractor.

Lubricants used for lubrication of parts including wet clutches or wet brakes, such as automatic transmissions and tractors, have good friction characteristics, oxidative stability, corrosion resistance, rust resistance, and also require high transmission torque. .

Conventionally, it is known that such a lubricant has a high static friction coefficient and a good transmission torque. However, this lubricating oil does not have enough friction characteristics and has a drawback in that the shift shock is large.

In particular, in recent years, due to the miniaturization of automobiles and the rapid increase of FF cars (front wheel drive vehicles), the tendency of miniaturization of automatic transmissions and the like has become more and more remarkable. This trend toward miniaturization of automatic transmissions promotes the adverse effect of shift shock being sensitively sensed by the human body. Therefore, it is a technical problem to aim at further improvement of a friction characteristic in order to make a shift shock small, and to make a riding comfort favorable.

Therefore, lubricating oil using a friction modifier has been proposed to improve the friction characteristics. However, the lubricating oil using the friction modifier has a problem that the friction characteristics are insufficient until now, the friction characteristics change with the change of the oil temperature, and the friction characteristics are deteriorated due to deterioration (time change) of the oil by long-term use. There was.

Therefore, lubricating oils having good friction characteristics, less change over time and time, and large transfer torques have not been obtained.

An object of the present invention is to solve the above-mentioned problems by containing a specific combination of compounds in a base oil, to reduce shift shock, to further increase transmission torque, and to lubricate an automatic transmission. It is to provide a lubricating oil composition that can be used.

That is, the present invention relates to a lubricating oil composition comprising 0.05% by weight of (A) alkenyl succinic acid ester and / or alkyl succinic acid ester and 0.005-5% by weight of fatty acid ester of (B) polyalcohol. .

The lubricating oil composition of the present invention has a small friction characteristic, that is, a static friction coefficient / dynamic friction coefficient, and has a small shock due to shifting.

Moreover, the change according to the oil temperature of the friction characteristics is small, and the change over time is also small. Therefore, the present invention can be sufficiently applied to downsizing of the transmission pillar.

The base oil used for this invention is a main component of a lubricating oil composition, and if it is used for a normal lubricating oil, various mineral oils and or synthetic oils can be used.

It is preferable that the viscosity of a base oil is 1.5-30 cst at 100 degreeC, and especially when using it as an oil for automatic transmissions and the wet brake oil of an agricultural tractor, it is preferable that it is 2-20 cst.

Specific examples of the base oil include 60 neutral oils, 100 neutral oils, 150 neutral oils, 300 neutral oils, 500 neutral oils and the like by solvent refining or hydrogenated refining.

On the other hand, examples of the synthetic oils include saturated hydrocarbons of condensed and / or non-condensed rings in addition to polyolefins, polyglycol esters, dibasic acid esters, polyol esters, phosphate esters, silicone oils, alkylbenzenes, alkyl diphenyls, and the like. The main component of which can be used as the base oil.

In the present invention, in the case of using mineral oil as the base oil, various kinds can be used as long as the kinematic viscosity at 100 ° C is 1.5-30 cst, preferably 2-20 cst, but the sulfur content is preferably 0.5% by weight or less. More preferably 0.1 wt% or less, most preferably 100 ppm or less can be used.

Here, when sulfur content exceeds 0.5 weight%, since oxidation stability falls, it is unpreferable.

Mineral oil can also use a thing with a low pour point. Preferably, a pour point is -15 degrees C or less, More preferably, it is -25 degrees C or less, Most preferably, it is -35 degrees C or less.

This is because the friction characteristics are further improved and the limitation of the use temperature range is alleviated.

The mineral oil has a preferable aromatic hydrocarbon content (% CA) of 20 or less, more preferably 10 or less, and a total acid value of 0.1 mg KOH / g or less, preferably 0.05 mg KOH / g or less.

Such mineral oil may be obtained by refining distilled oil (boiling point 250-450 ° C. in terms of normal pressure) obtained by distilling a paraffinic crude oil, an intermediate crude oil or a naprene crude crude oil according to a conventional method, or in this manner. It can be obtained by performing a deep dewaxing treatment.

In addition, distilled oil means what was obtained by atmospheric distillation of crude oil or distillation under reduced pressure of the residual oil of atmospheric distillation. There is no particular limitation on the refining method, but it can be obtained by carrying out any of the following ①-⑤.

(1) Alkaline distillation or sulfuric acid washing is carried out by hydrogenating or distilling the distilled oil.

(2) After distilled oil is subjected to solvent purification or solvent purification, hydrogenation, alkali distillation or sulfuric acid washing is performed.

(3) After distilling the distilled oil, a second step of hydrogenation is performed.

(4) After distillation of the distilled oil, the hydrogenation treatment of the second stage is carried out, and the hydrogenation treatment of the third stage is performed again.

(5) After distillation of the distilled oil, hydrogenation is carried out in the second step, followed by alkaline distillation or sulfuric acid washing. An example of the processing method is shown below.

Lubricating crude raw materials are prepared from paraffinic crude oil or intermediate crude crude oil by a conventional method, and subjected to severe hydrogenation treatment. By this treatment, a reaction is performed in which undesirable components are removed from the lubricating oil distillate such as an aromatic component and changed into an effective component. At this time, the sulfur component and the nitrogen component are also almost removed.

Next, fractional distillation is carried out to obtain the required viscosity by distillation under reduced pressure. Thereafter, known solvent desorption is performed, and desorption is carried out at a pour point of ordinary paraffinic base oil, that is, about -15--10 deg. After this dewaxing treatment, a hydrogenation treatment is further carried out as necessary, the majority of the aromatic components are hydrogenated to a saturated component, and the thermal and chemical stability of the base oil is improved.

When the distribution point of the mineral oil thus obtained is high and unsatisfactory, cardiac dewaxing is continuously performed.

This treatment is carried out by using a solvent dewaxing method or a zeolite catalyst under severe conditions, and adding catalytic hydrogen to remove the waxy component by selectively decomposing paraffin (usually normal paraffin) adsorbed to the micropores of the catalyst under hydrogen atmosphere. Applies to the lead-out method.

Although the hydrogenation treatment depends on the characteristics of the raw material oil, etc., the reaction temperature is generally 200-480 ° C, preferably 250-480 ° C, hydrogen pressure 5-300kg / cm ² , preferably 30-250kg / cm ² , and the amount of hydrogen introduced ( distillate oil is supplied to each 1kl) 30-3000Nm ^3, preferably is carried out under the conditions of 100-2000Nm ^3.

The catalyst used at this time may be alumina, silica, silica, alumina, zeolite, activated carbon, bake cyclic, or the like, and metals such as Group VI, Group VIII of the periodic table, preferably cobalt, nickel, What supported the catalyst component, such as molybdenum and tungsten, by the known method is used. In addition, the catalyst is preferably presulfurized in advance.

As described above, various treatments are carried out after the hydrogenation of the distilled oil, but in the case of performing the hydrogenation treatment of the second stage or the third stage, the hydrogenation treatment conditions may be set within the above range, Each condition of the step may be the same or different.

However, in general, the conditions of the second step rather than the first step and the third step rather than the second step are strictly performed.

Next, alkali distillation is performed as a step of removing traces of acidic substances to improve the stability of the distillation components, and by distillation under reduced pressure by adding alkali such as NaOH and KOH.

Moreover, sulfuric acid washing is generally performed as a finishing process of petroleum products, and is applied in order to remove aromatic hydrocarbons, especially polycyclic aromatic hydrocarbons, olefins, sulfur compounds, etc., and to improve the characteristic of distillate oil. In the present invention, 0.5-5% by weight of concentrated sulfuric acid is added to the process oil, and the mixture is treated at a temperature of room temperature -60 占 폚, and then neutralized with NaOH or the like.

In addition, although the specific method of (1)-(5) mentioned above is mentioned by combining the above operation by the process of distilled oil, the method of (1), (3), (4) is especially suitable among these methods.

The characteristics of the distilled oil obtained by the above process are the kinematic viscosity of 1.5-30 cst (100 degreeC), 0.5 weight% or less of sulfur components, and pour point -15 degreeC or less. In addition, the aromatic hydrocarbon content (% CA) is 20% or less, and the total acid value is 0.1 mg KOH / g or less.

By using such mineral oil, a lubricating oil composition with a smaller static friction coefficient / dynamic friction coefficient can be obtained.

Moreover, as synthetic oil, the saturated hydrocarbon of polyolefin, condensed ring, and / or non-condensed ring is preferable.

Although various things can be mentioned as such a saturated hydrocarbon, It is especially saturated hydrocarbon which has a cyclohexyl group and / or a decalyl group, It is preferable that it is C10-40.

Here, as a saturated hydrocarbon which has a cyclohexyl group and / or a decalyl group, Specifically, 2-methyl-2, 4- dicyclohexyl pentane; Cyclohexylmethyl decalin; 1- (methyldecalyl) -1-cyclohexylethane; 2,4-dicyclohexylpentane; Isododecylcyclohexane etc. are mentioned.

You may add a viscosity index fragrance | flavor, a corrosion inhibitor, etc. to base oil as needed.

In this invention, alkenyl succinic acid ester and / or alkyl succinic acid ester are used as (A) component.

Alkenyl succinic acid esters or alkyl succinic acid esters may be particularly effectively used as represented by the following general formula [1].

In the formula [1], R ¹ is an alkenyl group or an alkyl group having 6 to 30 carbon atoms, preferably 12 to 24 carbon atoms.

In the above [1], R ² and R ³ are hydrogen, an alkyl group having 1 to 20 carbon atoms, a hydroxyalkyl group having 1 to 20 carbon atoms, or a general formula.

Wherein R ⁴ is an alkylene group having 1 to ⁴ carbon atoms, R ⁵ is an alkyl group having 1 to 20 carbon atoms or a hydroxy substituent thereof, n is an integer of 0-6, and x is 1 or 2. Group.

R <^2> and R <^3> may be same or different here, except when both R <^2> and R <^3> are hydrogen.

Specific examples of the alkenyl succinic acid ester and the alkyl succinic acid ester include octadecenyl succinic acid monomethyl ester, octadecenyl succinic acid dimethyl ester, octadecenyl succinic acid monoethyl ester, octadecenyl succinic acid diethyl ester, octadecenyl succinate monooctyl Esters, octadecenyl succinic acid dioctyl ester, octadecenyl succinic acid monononyl ester, octadecenyl succinic acid dinonyl ester, octadecenyl succinic acid monolauryl ester, octadecenyl succinic acid lauryl ester, dodecyl succinic monolauryl Esters, dodecyl succinic dilauryl ester, hexadecyl succinic acid monomethyl ester, hexadecyl succinic acid dimethyl ester, hexadecyl succinic acid monoethyl ester, hexadecyl succinic acid diethyl ester, octadecyl succinic acid monomethyl ester, octadecyl ho Acid dimethyl ester, octadecyl succinic acid monoethyl ester, octadecyl succinic acid diethyl ester, octadecyl succinic acid monooctyl ester, octadecyl succinic acid dioctyl ester, octadecyl succinic acid monolauryl ester, octadecyl succinic acid dilauryl ester, average Reaction product of alkenyl amber acid of propylene oligomer of 18 carbon atoms with propylene glycol, reaction product of polybutenyl succinic acid and propylene glycol of polybutene having an average molecular weight of 400, octadecenyl succinate octyl mercaptan ethane oxide ester, octade Senyl succinate octylmercaptan propylene oxide ester, octadecenyl succinate nonyl mercaptan ethylene oxide ester, octadecenyl succinate nonyl mercaptan propylene oxide ester, octadecenyl succinate lauryl mercaptan ethylene oxide ester, octadecenyl ho Acid la may be mentioned lauryl mercaptan propylene oxide ester, octadecenyl succinic acid 5-hydroxy-3-thiazol-pentyl ester, octadecenyl succinic acid 6-hydroxy-3,4-thiazol-hexyl ester.

In the present invention, either one of the alkenyl succinic acid ester or the alkyl succinic acid ester or a mixture thereof is added as the component (A), but the amount of addition depends on the characteristics of the desired lubricating oil composition and the like, and cannot be defined constantly. .

However, it is usually 0.05-5.0% by weight, preferably 0.1-3.0% by weight. If the added amount is less than 0.05% by weight, a sufficient effect cannot be obtained, and if it is more than 5.0% by weight, the oxidation stability deteriorates, which is not preferable.

Next, in this invention, fatty acid ester of polyhydric alcohol is used as (B) component. Here, the polyhydric alcohols include glycerin, trimethylol propane, pentaerythritol, sorbitol, and the like, and glycerin is particularly preferable. Moreover, as fatty acid, it is C8-30, and either saturated or unsaturated may be sufficient. Specific examples of fatty acids include pelagonic acid, laric acid, palmitic acid, stearic acid, behenic acid, undecylenic acid, oleic acid, linoleic acid, and linolenic acid. More preferable esters include partial esters of polyhydric alcohols such as oleic acid monoglyceride, oleic acid diglyceride, stearic acid monoglyceride, stearic acid diglyceride and the like.

The addition amount of the said (B) component is 0.005-5 weight%, Preferably it is 0.01-3 weight%. If the amount is less than 0.005% by weight, the friction characteristics cannot be sufficiently improved. On the other hand, when it adds exceeding 5 weight%, since oxidation stability worsens, it is unpreferable.

Although the lubricating oil composition of this invention is obtained by mix | blending said (A), (B) component with a base oil fundamentally, an acid amide or its boron derivative in order to improve a friction characteristic and to improve the physical property as a lubricating oil at the same time. Can be added. As an acid amide, it is obtained by reaction of a C12-30 carboxylic acid and an amine compound, Specifically, with isostearic acid or oleic acid, and diethylene triamine, triethylene tetraamine, tetraethylene pentaamine, and hexaethylene pentaamine Reaction products, and the like. In addition, examples of the boron derivative of the acid amide include a reaction product of the acid amide and a boron compound (boric acid, borate, boric acid ester). Specifically, what was obtained by making boric acid react with said acid amide, for example, the reaction product of isostearic acid and tetraethylene pentaamine again is mentioned. The addition amount is 0.01-10% by weight, preferably 0.05-3% by weight. At an added amount of less than 0.01% by weight, sufficient frictional properties are not obtained, and an effect of improving and dispersing cleanness is not obtained. On the other hand, when added to exceed 10% by weight, the static friction coefficient is lowered and the transmission torque is not preferable. Moreover, in the lubricating oil composition of this invention, antioxidant, a clean dispersing agent, a viscosity index improver, etc. can be added suitably. As antioxidant, what is necessary is just what is generally used, such as a phenol type compound, an amine compound, and dithiophosphate.

Specifically, 2, 6- di-t- butyl- 4-methyl- phenol; 2,6-di-t-butyl-4-ethyl-phenol; 4,4'-methylenebis (2,6-di-t-butyl-phenol); Phenyl-α-naphthylamine; Dialkyldiphenylamine; Zinc di-2-ethylhexyldithiophosphate; Diamyldithiocarbamate zinc; And pentasulphine pinene. The amount added is 0.01-3% by weight, preferably 0.05-2% by weight.

If it is less than 0.01 weight%, there is no effect and even if it exceeds 3 weight%, the remarkable improvement is not recognized.

Next, as the detergent dispersant, an ashless detergent, a metal detergent, or the like can also be used. Specifically, alkenyl succinate imide, sulfonate, phenate, etc. are preferable, for example, polybutenyl succinate imide, calcium sulfonate, barium sulfonate, calcium salicylate, etc. are mentioned.

The amount added is 0.1-10% by weight, preferably 0.5-5% by weight. If it is less than 0.1% by weight, dispersibility is insufficient, and if it is more than 10% by weight, the friction property is lowered, which is not preferable.

Although there is no restriction | limiting in particular as a viscosity index improver, Polymethacrylate, an olefin copolymer, etc. can be used. In particular, polymethacrylates having a molecular weight of 100,000 or less, preferably 50,000 or less, which are excellent in shear stability and can prevent a viscosity change for a long time are suitable. The amount added is 0.5-15% by weight, preferably 2-10% by weight. If it is less than 0.5% by weight, the improvement of the viscosity-temperature characteristic is not recognized, and if it exceeds 15% by weight, since a low viscosity base oil is used, deterioration in wear resistance or the like is not preferable.

In addition, a corrosion inhibitor, a rubber swelling agent, an antifoamer, etc. can be added to the lubricating oil composition of this invention as needed. Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1-2 and Comparative Example 1-2

5 kst of kinematic viscosity at 100 ° C as a base oil, 4.0 wt% of polymethacrylate (molecular weight 42,000), 4.0 wt% of polybutenyl succinate (polybutenyl group molecular weight 1000) and acid amide in mineral oil I having a sulfur component of 200 ppm To the base oil to which the weight% was added, the predetermined amount of compounds shown in Table 1 were added to obtain a lubricating oil composition.

The obtained lubricating oil composition was tested by the following method.

SAE No, 2 Friction Test

Greening Co., Ltd., SAE NO, 2 tester was used to evaluate the friction characteristics under the following experimental conditions.

[Experimental Conditions]

Disk: Paper-based disk (two pieces) for Japanese automatic transmission

Plate: Forced plate (four pieces) for Japanese automatic transmission

RPM of motor: 3000rpm

Compression pressure of piston: 3 kg / cm ²

Oil temperature: 50 degrees Celsius, 80 degrees Celsius, 100 degrees Celsius, 120 degrees Celsius

The kinetic friction coefficient at the rotational speed of 1200 rpm under the above experimental conditions was measured at µ ₁₂₀₀ and the static friction coefficient at the time of stopping was set to µ ₀ , and µ ₀ / µ ₁₂₀₀ was calculated.

In other words, to measure the time variation of μ ₀ / μ ₁₂₀₀ in the oil temperature 100 ℃ to 2000 cycles. The time-dependent change of mu ₀ / mu ₁₂₀₀ in each time (100, 200, 300, 400, 500, 1000, 1500, 2000 cycles) up to 2000 cycles is shown in FIG. In addition, (micro | _{micron |} mu) ₀ / micro ₁₂₀₀ value in 200 cycles and 2000 cycles is shown in Table 1 as a result of an endurance test.

Next, after commissioning from the oil temperature of 100 degreeC to 200 cycles, (micro | micron | mu ₎ / micro | micron ₁₂₀₀ was measured at each temperature at the time of changing oil temperature to 50, 80, 100, 120 degreeC in steps. The results are shown in FIG. In addition, (micro | _{micron |} micro | micron | _{micro |} micron | mu ₎ / ₁₂₀₀ micrometers value in 50 degreeC and 120 degreeC is shown in Table 1 as a result of a temperature dependency test.

[Comparative Example]

About a commercial item, the friction characteristic was evaluated like Example 1. The results are shown in Table 1, Figure 1 and Figure 2.

Example 3-4 and Comparative Example 4

The lubricating oil composition shown in Table 1 was obtained and tested similarly to Example 1-2 and Comparative Example 1-2 except having used mineral oil II which has the following characteristic as a base oil. The time-dependent change of (mu) ₀ / (mu) ₁₂₀₀ in each time up to 2000 cycles is shown in FIG. In addition, the results of the endurance test and the temperature dependency test are shown in Table 1.

Characteristics of Mineral Oil Ⅱ

Kinematic Viscosity (100 ° C): 5.0cSt

Sulfur Component (ppm): 1

Pour point: -45 ℃

% C _A : 0.1>

Example 5-10 and Comparative Example 5

The lubricating oil composition shown in Table 1 was tested in the same manner as in Example 1-2 and Comparative Example 1-2. The results of the endurance test and the temperature dependence test are shown in Table 1. In addition, in base oil, 4.0 weight% of polymethacrylates (molecular weight 42,000) and polybutenyl succinimide (polybutenyl group molecular weight) similarly to Example 1-2 and Comparative Example 1-2 (the other Example and comparative example are also the same) 1,000) 4.0% by weight and 0.5% by weight of acid amide were added.

[Table 1]

* One

Mineral oil I: Kinematic viscosity at 100 ° C 5cst, sulfur component 2000ppm, fluidity -17.5 ° C,% C _A 6

Mineral oil II: Kinematic viscosity at 100 ° C 5.0 cst, sulfur component (ppm) 1> Pour point -45 ° C,% C _A 0.1>

Synthetic oil III: alpha-olefin oligomer (kinetic viscosity 4cst at 100 degreeC)

Synthetic oil IV: 2-methyl-2,4-dicyclohexyl pentane (kinetic viscosity 3.7 cst at 100 ° C)

* 2A ₁ : octadecetyl succinic acid monolauryl ester

* 3A ₂ : Octadecenyl succinate octyl mercaptan propylene oxide ester

* 4A ₃ : octadecenyl succinic acid 5-hydroxy-3-thiapentyl ester

* 5B ₁ : Oleic acid monoglyceride

* 6B ₂ : sorbitan monooleate

From Tables 1 and 3, it can be seen that the lubricating oil composition of the present invention is excellent in friction characteristics. In particular, from the results of the temperature dependency test, it can be seen that the change of the friction characteristics due to the oil temperature is extremely small. Therefore, the lubricating oil composition of this invention is extremely effective as lubricating oil of the part containing a wet clutch or wet brakes, such as an automatic transmission, a tractor, and a wet brake.

Moreover, the composition which combines such a characteristic is also effective as lubricating oils, such as an impact shock absorber, a power steering, hydraulic suspension, and these many objective combined oils.

Claims (2)

The base oil contains 0.05-5% by weight of (A) alkenyl succinic acid ester and / or alkyl succinic acid ester and 0.005-5% by weight of fatty acid ester of (B) polyhydric alcohol. The lubricating oil composition according to claim 1, wherein the base oil contains 0.5 wt% or less of a sulfur component.

Images