KR20100008262A - Grease composition for constant velocity joint - Google Patents

Abstract

PURPOSE: Grease composition for constant velocity joint is provided to improve the abrasion resistance, and to reduce the frictional force by using molybdenum dithiophosphate, molybdenum dithiocarbamate, zinc dithiophosphate and sulfur ester-based additive. CONSTITUTION: Grease composition for constant velocity joint comprises base oil 75.0~88weight%, thickening agent 7.0~10.0weight%, and additive 3.6~15weight%. The additive comprises Sulfur ESTER additive, Mo-DTC, Mo-DTP, and Zn-DTP. The thickening agent comprises 1:2.2 ~ 1:2.4 weight% of aliphatic diurea and alicyclic diurea. The base oil is mineral oil that the dynamic viscosity is 60~100mm^2/s when the temperature is 40 degree.

Description

Grease composition for Constant Velocity Joint

The present invention relates to a grease composition for a constant velocity joint.

Typically, the co-speed joint receives the driving and braking torque transmitted from the transmission output stage and the tire, and serves to transmit power to the tire regardless of the bending angle of both shafts connected to the joint. The grease that is sealed to such a constant velocity joint reduces the lateral fluctuations of low frequency caused by low stage and rapid acceleration, which cause the vehicle shudder, and the vibration phenomenon during stop (Idle) by using the foot brake of the automatic transmission vehicle. Serves to prevent. In addition, wear occurs between the outer ring and the roller according to the bending angle of the joint. If the wear resistance of the grease is low, abnormal wear may occur and vehicle shaking may occur.

Thus, the present invention, as a result of research efforts to solve the above problems, using mineral oil as a base oil urea-based thickener as a thickener, sulfur ester (Sulfur ESTER) additive, molybdenum dithiocarbamate (Mo -DTC), molybdenum dithiophosphate (Mo-DTP), zinc dithiophosphate (Zn-DTP) is found to be able to significantly improve the friction reduction and wear resistance compared to the conventional grease, It was completed.

Accordingly, the present invention uses a mineral oil as a base oil, urea thickener, Sulfur ester additive, molybdenum dithiocarbamate (Mo-DTC), molybdenum dithiophosphate (Mo-DTP), It is an object to provide a grease composition for constant velocity joints containing zinc dithiophosphate (Zn-DTP).

The present invention

In a grease composition containing a base oil, a thickener and an additive,

Base oil 75.0-88 wt%;

Thickener 7.0-10.0 wt% comprising aliphaticdiurea and alicyclicdiurea mixed in a weight ratio of 1: 2.2 to 1: 2.4; And

Sulfur ester-based additives, additives including molybdenum dithiophosphate (Mo-DTP), molybdenum dithiocarbamate (Mo-DTC) and zinc dithiophosphate (Zn-DTP) weight%

Characterized in that the grease composition for a constant velocity joint comprising a.

The present invention is described in more detail as follows.

In the present invention, mineral oil is used as base oil, and urea thickener, sulfur ester additive, Mo-DTP, Mo-DTC, and Zn-DTP are added to lower the friction coefficient between metals and improve wear resistance. The purpose of the present invention is to provide a grease composition for a constant velocity joint that ensures axial force, PR reduction, and improved durability.

Although the base oil which can be used by such this invention can be used if it is a base oil normally usable for grease, mineral oil base oil is preferable. The mineral oil may include one prepared by solvent purification or hydrogenation, and may include paraffinic mineral oil, naphthenic mineral oil, and the like.

The base oil containing the preferred mineral oil as the main component of the present invention preferably has a kinematic viscosity of 40 to 100 mm ² / s at 40 ° C. At this time, if the kinematic viscosity is less than 60 cSt heat resistance is easy to evaporate, if the kinematic viscosity exceeds 100 mm ² / s, the torque is large, there is a problem that the calorific value increases.

The preferred content of the base oil used in the present invention is 75.0 to 88.0% by weight based on the entire grease composition, wherein if the base oil content is less than 75.0% by weight, it is too hard to be practical to grease, and if it exceeds 88.0% by weight, It is not preferable because of high reason and softening problem.

The thickener used in the present invention is alicyclic diurea (formula 1), toluene diisocyanate (TDI) and oleyl obtained by reacting diphenylmethane-4,4-diisocyanate (MDI) with cyclohexylamine. Aliphatic diurea (Formula 2) obtained by reacting an amine (Oleylamine) is mixed in an appropriate ratio, and its content is preferably in the range of 7.0 to 10.0% by weight based on the total grease composition. If the content is less than 7.0% by weight, the liquidity is high, and the oil is easily separated, and when the content exceeds 10.0% by weight, the solidification occurs and the fluidity decreases.

R ¹ NH-CO-NH-C ₆ H ₄ -p-CH ₂ -C ₆ H ₄ -p-HN-CO-NHR ¹

In Formula 1, R ¹ represents a cyclohexyl group having 6 carbon atoms.

2,4- [R ² NH-CO-NH] ₂ -C ₆ H ₃ -CH ₃

In Formula 2, R ² represents an oleyl group having 18 carbon atoms.

A urea thickener is obtained by reacting an isocyanate and an amine compound, and in order to leave no amine group, it is preferable to mix | blend an isocyanate and an amine compound so that it may correspond approximately equivalently. In addition, in the mixing ratio of aliphatic diurea and alicyclic diurea, a weight ratio of 1: 2.2 to 1: 2.4 is appropriate in consideration of curing properties at high temperatures and softening properties at shear.

On the other hand, the additive used in the present invention is 3.6 to 15% by weight based on the total composition, it may include a sulfur ester-based additive, Mo-DTP, Mo-DTC, Zn-DTP.

In particular, molybdenum dithiocarbamate and molybdenum dithiophosphate, which are friction improving and abrasion inhibitors, are represented by the following Chemical Formulas 3 and 4, respectively.

[R ³ R ⁴ N-CS-S] ₂ -Mo ₂ O _m S _n

In Formula 3, R ³ and R ⁴ are the same or different, and represent an alkyl group having 1 to 24 carbon atoms, m + n = 4, m is 0-3, and n is 1-4.

In Formula 4, R ⁵ , R ⁶ , R ⁷ and R ⁸ each represent a 1 to 24 carbon atoms, a secondary alkyl group or a 6 to 30 carbon atoms aryl group.

The additive is used to improve the frictional performance, extreme pressure and abrasion resistance, and molybdenum dithiocarbamate is preferably added in an amount of 1.5 to 4.0% by weight based on the entire grease composition. In this case, no further improvement effect can be expected, and if less than 1.5% by weight, the effect of sufficient friction improvement cannot be obtained. In addition, the molybdenum dithio phosphate is preferably used 0.1 to 1.0% by weight based on the entire grease composition, if the content exceeds 1.0% by weight, the anti-wear effect no longer increases, 0.1 weight If less than%, there is a problem that wear resistance is reduced.

Sulfur ester additives that maintain a stable coefficient of friction and wear resistance are preferably added 1.0 to 3.0% by weight based on the total grease composition. If it is used in excess of 3.0 wt% or less than 1.0 wt%, there is a problem of unstable friction and wear resistance.

In addition, it is preferable to add 1.0 to 3.0% by weight of the zinc dithiophosphate that enhances the friction characteristics of molybdenum dithiocarbamate based on the total grease composition. If it exceeds 3.0% by weight, the wear protection effect no longer increases, and when added below 0% by weight, sufficient wear protection effect is not obtained.

In addition to the sulfur ester-based additives, Mo-DTP, Mo-DTC, Zn-DTP as an additive in the composition of the present invention, the extreme pressure additives, antioxidants, corrosion inhibitors, and the like, which are conventionally added to grease, may be further added.

By using a well-known extreme pressure agent together as an extreme pressure additive, load resistance and extreme pressure resistance can be improved. For example, the following compounds can be used. Namely, organic zinc compounds such as zinc dithiocarbamate, zinc dithiophosphate and zinc phenate, organic antimony compounds such as dithiocarbamate antimony and antimony dithiophosphate, bismuth naphthenate and bismuth dithiocarbamate Organic bismuth compounds such as organic metal compounds such as organic metal phosphates, phenates, phosphates, gold, silver, titanium, and cadmium may be used if necessary. Examples of the sulfur compound include sulfides or polysulfide compounds such as dibenzyl disulfide, sulfurized oils and fats, ashless carbamin oxidized logistics, thiourea compounds, or thiocarbonates. As a phosphate extreme pressure agent, phosphate ester compounds, such as a phosphate ester, such as toric octyl phosphate and a tricredil phosphate, an acidic phosphate ester, a phosphite ester, and an acid phosphite ester, can be used. In addition, halogen-based extreme pressure agents such as chlorinated paraffin, or solid lubricants such as boron compounds such as molybdenum disulfide, tungsten disulfide, graphite, polytetrafluoroethylene (PTFE), antimony sulfide and boron nitride can be used. As antioxidant, it can select suitably from antioxidant, ozone deterioration agent, and antioxidant which are added to rubber | gum, plastic, lubricating oil, etc., and can be used. For example, the following compounds can be used. That is, phenyl-1-naphthylamine, phenyl-2-naphthylamine, diphenyl-p-phenylenediamine, dipyridylamine, phenothiazine, N-methylphenothiazine, N-ethylphenothiazine, 3,7-dioctylphenothiazine, p, p'-dioctyldiphenylamine, N, N'-diisopropyl-p-phenylenediamine, N, N'-di-sec-butyl-p-phenylenediamine Amine compounds, such as these, and phenolic compounds, such as 2, 6- di-tert- dibutyl phenol, etc. can be used.

As a corrosion inhibitor, the following compounds can be used, for example. That is, alkyl, such as ammonium salt of eutectic acid, alkali metals, such as barium, zinc, calcium, magnesium, the organic-technical acid salt of alkaline-earth metal, organic carbonate, phenate, phosphonate alkyl, or alkenyl zucic acid ester, Derivatives partial esters of polyhydric alcohols such as sorbitan monooleate, hydroxy fatty acids such as oleoyl zalcosine, mercapto fatty acids such as 1-mercapto stearic acid, or higher fatty acids such as metal salt stearic acid, isostearyl alcohol, etc. Higher alcohols; esters of higher alcohols and higher fatty acids; thiazoles 2- (decyldithio) -benzoimime such as 2,5-dimercapto-1,3,4-thiadiazole and 2-mercaptothiadiazole Imidazole compounds such as dazoazole and benzoimidazole, disulfide compounds such as 2,5-bis (dodecyldithio) benzoimidazole, or phosphate esters such as trisnonylphenylphosphite, dira Thiocarboxylic acid ester type compounds, such as a uryl thio propionate, etc. can be used. Moreover, nitrite etc. can also be used.

The grease according to the present invention can increase the mechanical stability and the water resistance by the added urea thickener, and improve the adhesiveness, and the sulfur ester-based additive, Mo-DTP, Mo in the grease blended with the base oil and the urea thickener. -DTC and Zn-DTP can be added to reduce friction and improve wear resistance to extend the lubrication life of the application.

The grease composition for constant velocity joint according to the present invention, using a Zn-DTP and sulfur ester additives to maintain a stable coefficient of friction at high and low temperature conditions, and the coefficient of friction between metals using Mo-DTP and Mo-DTC It has the effect of reducing the axial force and PR by lowering and increasing wear resistance.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to Examples.

Production Example  One: Alicyclic Diurea  Produce

4500 g of base oil and 558 g of diphenylmethane-4,4'-diisocyanate were placed in a container and the mixture was heated to a temperature in the range of 70 to 80 ° C. 4500 g of base oil and 442 g of cyclohexylamine were mixed in a separate container, and the mixture was put into the container. The temperature of this mixture was raised to 170 ° C. with sufficient stirring, and then left to obtain a base urea grease.

Production Example  2: Aliphatic diurea  Produce

4550 g of base oil and 362.7 g of toluene-2,6-diisocyanate were added to the vessel, followed by sufficient stirring. 4550 g of base oil and 537.3 g of oleylamine were added and mixed in a separate container, and the mixture was added to the container. The temperature of this mixture was raised to 170 degreeC with sufficient stirring, and it left to stand and obtained base urea grease.

Example  1-3 and Comparative example  1 ~ 2

By following the composition in Table 1 to prepare a constant velocity joint grease.

As the base oil shown in Table 1, mineral oil (kinematic viscosity: 95 cSt at 40 ° C.) was used. In addition, as urea-based thickener, alicyclic diurea prepared from Preparation Example 1 and aliphatic diurea prepared from Preparation Example 2 were used, and alicyclic diurea and aliphatic diurea were used at a ratio of 1: 2.3. Mixed.

The grease composition was prepared by conventional methods.

Classification (Unit: wt%) Example Comparative example One 2 3 One 3 Base oil Mineral oil 85.7 85.5 87.3 86 87.5 Thickener Ali Cyclic Diurea 6.6 6.3 6.3 9.5 - Aliphatic diurea 2.9 2.7 2.7 - 9.0 additive 1) Molybdenum Dithiocarbamate 2.2 2.0 1.7 - 2.0 2) molybdenum dithiophosphate 0.1 - - 0.1 - 3) Sulfur ester 1.0 2.0 1.0 1.0 - 4) Zinc Dithio Phosphate 1.5 1.5 1.0 1.5 1.5 1) Molybdenum dithiocarbamate: Sakuralube 200 from Adeka. 2) Molybdenum dithiophosphate: Sakuralube 300 from Adeka. 3) Sulfur esters: Lubrizol 5333. 4 from zinc bridol.

Test Example  : Check physical properties

Physical properties of the grease for constant velocity joints prepared in Examples 1 to 3 and Comparative Examples 1 and 2 were measured by the following method, and the results are shown in Table 2 below.

1) Mixing Lead: Measured according to ASTM D 217 (Method of Measuring Grease Lead).

2) Dropping point: It was performed according to ASTM D 566 (method for measuring the dropping point of grease).

3) Reasonability: Measured according to ASTM D6184 (Method for Measuring Grease Weakness).

4) Friction Coefficient (SRV): 100Hz, 300N, 500N load 10Hz reciprocating speed, 4mm reciprocating according to ASTM D 5707-05 (Standard measurement method for measuring friction and wear resistance of grease using high frequency SRV tester) Measured under distance.

division Example Comparative example One 2 3 One 3 Mixed Race @ 25 ℃ 321 325 323 325 325 Dropping point ℃ 235 237 234 235 232 Reason wt.% 0.7 0.6 0.7 0.7 0.7 Friction Coefficient (SRV) 0.060 0.070 0.068 0.09 0.105

As shown in Table 2, Examples 1 to 3 show good results at the reason and dropping point showing the durability and operability of the grease at high temperature by using the urea thickener having excellent critical heat resistance temperature. In the friction test using additives, Mo-DTP, Mo-DTC, and Zn-DTP, the friction coefficient is superior to that of the comparative example.

Claims (7)

In a grease composition containing a base oil, a thickener and an additive, Base oil 75.0-88 wt%; Thickener 7.0-10.0 wt% comprising aliphaticdiurea and alicyclicdiurea mixed in a weight ratio of 1: 2.2 to 1: 2.4; And Sulfur ester-based additives, additives including molybdenum dithiophosphate (Mo-DTP), molybdenum dithiocarbamate (Mo-DTC) and zinc dithiophosphate (Zn-DTP) weight% Grease composition for a constant velocity joint, comprising a. The composition of claim 1, wherein the base oil is a mineral oil having a kinematic viscosity at 40 ° C of 60 to 100 mm ² / s. According to claim 1, wherein the alicyclic diurea is a composition characterized in that the compound represented by the following formula (1); [Formula 1] R ¹ NH-CO-NH-C ₆ H ₄ -p-CH ₂ -C ₆ H ₄ -p-HN-CO-NH R ¹ In Formula 1, R ¹ represents a cyclohexyl group having 6 carbon atoms. According to claim 1, wherein the aliphatic diurea is a composition characterized in that the compound represented by the formula (2); [Formula 2] 2,4- [R ² NH-CO-NH] ₂ -C ₆ H ₃ -CH ₃ In Formula 2, R ² represents an oleyl group having 18 carbon atoms. The method of claim 1, wherein the additive is a sulfur ester-based additive 1.0 to 3.0% by weight, molybdenum dithiophosphate 0.1 to 1.0% by weight, molybdenum dithiocarbamate 1.50 to 4.0% by weight, zinc dithiophosphate 1.0 ~ Composition comprising 3.0% by weight. According to claim 1, wherein the molybdenum dithio carbamate is a composition characterized in that the compound represented by the formula [Formula 3] [R ³ R ⁴ N-CS-S] ₂ -Mo ₂ O _m S _n In Formula 3, R ³ and R ⁴ are the same or different, and represent an alkyl group having 1 to 24 carbon atoms, m + n = 4, m is 0-3, and n is 1-4. According to claim 1, wherein the molybdenum dithio phosphate is a composition characterized in that the compound represented by the formula [Formula 4]

In Formula 4, R ⁵ , R ⁶ , R ⁷ and R ⁸ each represent a 1 to 24 carbon atoms, a secondary alkyl group or a 6 to 30 carbon atoms aryl group.