KR20180113756A - Grease composition for constant velocity joint comprising nano-size solid lubricant and method for manufacturing the same - Google Patents

Abstract

The present invention discloses a grease composition for a constant velocity joint comprising a nano-sized solid lubricant and a method for manufacturing the same. The grease composition for constant velocity joint, which is one aspect of the present invention, exhibits physical properties optimized for the lightweight constant velocity joint, and can reduce noise and vibration in automobiles. Further, the grease composition according to one aspect of the present invention has excellent physical properties through the optimal combination of components in the composition, and at the same time has an economical effect of cost reduction.

Description

TECHNICAL FIELD [0001] The present invention relates to a grease composition for a constant velocity joint including a nano-sized solid lubricant, and a method for producing the grease composition. [0002]

Disclosed herein are a grease composition for a constant velocity joint comprising a nano-sized solid lubricant and a method for producing the same.

Constant Velocity Joint (CV-Joint) is a device that receives the power generated from an automobile engine from a transmission and delivers it to the wheels. CV-Joint rubber boots are filled with grease to help lubricate the components in the rubber boots.

Since the CV-Joint performs complicated rolling and sliding movements during rotation, it causes slide resistance in the axial direction, which causes body shake at the time of oscillation and acceleration, as well as in the automobile interior noise and / or vibration at a specific speed . In recent years, efforts have been made to reduce the weight of automobiles through weight reduction for improving fuel economy. In order to solve the above problems and needs, efforts have been made to change the materials and structures of parts included in the CV- No grease has been developed yet which is optimized for a lightweight CV-Joint and solves all of the above problems.

KR2004-0020408A

In one aspect, an object of the present invention is to provide a grease composition for constant-velocity joints having improved load-bearing property, abrasion resistance, lead, redness, evaporation amount and reasonability.

In one aspect, an object of the present invention is to provide a grease composition for a constant velocity joint optimized for lightweight constant-velocity joints.

In order to achieve the above object, Thickener; And a lubricant, wherein the thickener comprises an isocyanate and an amine-based material, and the isocyanate and the amine-based material are contained in a molar ratio of 1: 0.5 to 5, respectively.

In one aspect, the present invention provides a base oil composition comprising: a base oil; Thickener; Lubricant; And mixing the additive with the additive. The present invention also provides a method for producing a grease composition for a constant velocity joint.

The grease composition for a constant velocity joint, which is one aspect of the present invention, exhibits properties optimized for a lightweight constant velocity joint and can improve noise and vibration in automobiles. Further, the grease composition according to one aspect of the present invention has excellent physical properties through an optimal combination of components in the composition, and at the same time has an economical effect of cost reduction.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a test report certifying the physical properties of a composition according to one aspect of the present invention.
Figure 2 is a flow chart illustrating a method of making a composition that is an aspect of the present invention.
3 is a graph showing changes in wear and extreme pressure properties depending on the content of WS ₂ .
4 is a graph showing changes in wear and extreme pressure properties depending on MoDTC content.
FIG. 5 is a graph showing changes in the main physical properties depending on the content of the thickener.
Fig. 6 is a graph showing the change in the physical properties of the reasons depending on the content of the thickener.
FIG. 7 is a diagram showing change in physical properties depending on the content of the thickener. FIG.
8 is a graph showing the FT-IR analysis results of MDI. Fig. 8 (a) shows the results when heated, Fig. 8 (b) shows the results when heated to 200 캜, and Fig.

Hereinafter, the present invention will be described in detail.

The present invention, in one aspect, Thickener; And a lubricant, wherein the thickener comprises an isocyanate and an amine-based material, and the isocyanate and the amine-based material are contained in a molar ratio of 1: 0.5 to 5, respectively.

In one aspect, the iocyanate and the amine-based material may each be contained in a molar ratio of 1: 0.5 to 5, preferably 1: 0.5 to 3, more preferably 1: 1 to 3.

In one aspect, the isocyanate may include methylene diphenyl diisocyanate (MDI).

In addition, in the above-mentioned aspects, the amine-based material may be at least one selected from the group consisting of octylamine; And cyclohexylamine. ≪ / RTI >

In one aspect, the composition includes an isocyanate and an amine-based material as a thickener, so that a redox that is optimized for a constant velocity joint, that is, a redox of 240 deg. C or more can be obtained. The inventors of the present invention have confirmed that when a lithium-containing material is used as the thickening agent, the melting point is about 190 캜, which is not suitable for lightweight constant velocity joints.

In one aspect, the composition may comprise octylamine and cyclohexylamine in a molar ratio of 1: 0.5 to 5, respectively. The octylamine and the cyclohexylamine may be contained in a molar ratio of 1: 0.5 to 5, preferably 1: 0.5 to 2, more preferably 1: 0.8 to 1.2, respectively.

The isocyanate, octylamine, and cyclohexylamine may be included in a molar ratio of 1: 0.8 to 1.2: 0.8 to 1.2, respectively, and in one embodiment, in a molar ratio of about 1: 1: 1. When the isocyanate, octylamine and cyclohexylamine are contained in a molar ratio of 1: 0.8 to 1.2: 0.8 to 1.2, respectively, excellent physical properties can be obtained.

In one aspect, the lubricant in the composition may comprise a lubricant having an average diameter of from 0.1 to 900 nm. Preferably, the mean diameter of the lubricant may range from 10 to 100 nm.

In the present specification, the average diameter may mean an average value of two axes which are arbitrarily measured excluding the longest axis and the shortest axis length of the particle.

In one aspect, the lubricant comprises a lubricant having an average diameter of nano-size, thereby minimizing friction between the parts in the constant velocity joint at boundary friction and extreme pressure friction conditions occurring within the constant velocity joint, As a result, the mechanical efficiency of the constant velocity joint can be maximized.

In this respect, the lubricant may be molybdenum disulfide or tungsten disulfide, preferably tungsten disulfide (WS ₂ ).

In one aspect, the composition may further comprise an additive, and the additive may include molybdenum di thiocarbamate (MoDTC).

As used herein, additives include all materials used to improve the physical properties of compositions other than base oils, thickeners, and lubricants.

In general, ZnDTP (zinc dialkyl dithiophosphate) is used as an additive for grease for constant velocity joint, but there is no synergistic effect with the thickener according to one aspect of the present invention. On the other hand, by using molybdenum dithiocarbamate as an additive, the composition according to the present invention can obtain a synergistic effect on wear and extreme pressure characteristics.

In one aspect, the base oil in the composition may comprise paraffin oil. The composition according to the present invention is economical because it can secure excellent physical properties without containing an expensive oil such as polyalphaolefin.

In one aspect, the composition comprises 70 to 80% by weight base oil, based on the total weight of the composition; 10 to 20% by weight thickener; And 1 to 10% by weight of a lubricant.

Specifically, the base oil may be contained in an amount of 70 to 80% by weight, preferably 72 to 78% by weight, and more preferably 74 to 77% by weight, based on the total weight of the composition. When the base oil is included in the above amount, an optimized effect can be obtained from the composition. In particular, when it exceeds 80% by weight, a curing phenomenon occurs. When it is less than 70% by weight, there is a limit that the miscibility of lead is weakened.

Also, the thickener may be included in an amount of 10 to 20% by weight, preferably 12 to 20% by weight, more preferably 12 to 18% by weight, based on the total weight of the composition, %. ≪ / RTI > When the thickener is included in the above content range, a composition having an optimized redness, moisture resistance and evaporation amount can be obtained.

In addition, the lubricant may be included in an amount of 1 to 10% by weight based on the total weight of the composition. The lubricant may be contained in an amount of 1 to 10% by weight, preferably 1 to 8% by weight, more preferably 4 to 6% by weight, based on the total weight of the composition. Within this range, the composition may exhibit excellent wear properties.

Also, the content of the additive contained in the composition may be 0.1 to 1% by weight based on the total weight of the composition. The additive may preferably be contained in an amount of 0.1 to 0.8% by weight, more preferably 0.5 to 0.8% by weight. When the content of the additive is less than 0.1% by weight, the synergistic effect of improving the physical properties does not occur, and when it exceeds 0.8% by weight, the synergistic effect hardly increases.

In one aspect, the composition may comprise one or more of the following properties:

1) a luminescence value measured at 25 占 폚 according to ASTM D217-10 of not less than 240;

2) The measured point according to KS M ISO 2176: 2003 is 265 ~ 295 ℃;

3) Abrasion resistance measured according to ASTM D2266-01 (2015) of not more than 0.5;

4) Load resistance of 500 or more as measured according to ASTM D2596-14;

5) Reasonable degree measured at 100 ℃ according to KS M ISO 2050: 1996 is less than 3.0; And

6) The evaporation amount measured according to KS M ISO 2037: 1990 is less than 0.5.

The lead in this specification may include miscible lead and miscible lead. The test method specified by ASTM D 217 and KS M ISO 2137 is to fill the test vessel with grease, flatten it, and then free fall of the specified cone to show the depth entering for 5 seconds in 1 / 10mm increments. The mixing lead can be measured after the grease sample is filled in the mixer and maintained at 25 ° C and then reciprocated 60 times. The composition of the present invention exhibits type 2 physical properties as shown in Table 1 below.

American National Lubricating Grease Institute (NLGI) Intrusion (0.1mm) condition 000 445 to 475 Liquid phase 00 400 ~ 430 Almost liquid 0 355 to 385 Extremely tender One 310 ~ 340 Very tender 2 265 to 295 Tenderness 3 220-250 Moderate degree 4 175 ~ 205 stiffness 5 130 ~ 160 Extremely hard 6 85 ~ 155 solid

The redness indicates the heat resistance of the grease and indicates the temperature at which the sample is heated under constant test conditions and drops to the bottom of the test tube through an open nipple (the temperature at which the semi-solid grease turns into a liquid state). Although the red dot does not indicate the maximum operating temperature, the maximum operating temperature is usually determined at a temperature of 40 ° C or less at the point of red light. The red spot is tested in accordance with KS M ISO 2176. The sample is put into the red cup without air and put in the test tube. The test tube with the sample cup is put in the hot water boiler heated to 300, and the grease oil is separated by heat The temperature can be measured.

The load-bearing property may mean a welding load. The fusing load is measured by putting a grease composition between four steel balls and rotating the top steel ball to the maximum permissible load which can not be welded when pressure is applied is expressed as N (Newton) or kg. On the other hand, the wear amount can be measured by checking the degree of abrasion occurring on the surface of the steel ball after all four balls are rotated for one hour.

The reason for this is that the amount of oil separated from the grease under the constant test conditions (100 ° C, 24 hours) is expressed as% by weight (wt%). The reason is tested according to KS M 2050, It can be obtained by measuring the weight of oil dropped on the bottom of the cup after separating about 10g of grease into a chrome-nickel plated conical net without bubbles and forming an upper rounded arcuate shape for 100 to 24 hours.

The amount of evaporation is a test for confirming the content of water and base oil contained in the grease. The purpose of the test is to confirm deterioration of the lubricant at a high temperature region due to the inclusion of the hard mineral oil of the grease. The test method can be tested in accordance with KS M ISO 2037. Evaporation amount The sample is put into the cup as much as possible without generating air, and the weight is measured. The drying weight is measured by blowing dry air for 2 hours at 99 ° C for 22 hours.

In one aspect of the present invention, there is provided a method for producing a grease composition for a constant velocity joint,

The method comprises the steps of: Thickener; Lubricant; And a step of mixing the additive with the additive.

The mixing step may comprise the following steps:

1) mixing a base oil and a thickener; And

2) mixing the lubricant and additive in a mixture of base oil and thickener.

The step of mixing the base oil and the thickener comprises mixing 70 to 90% by weight of base oil and isocyanate based on the total weight of the base oil in the composition and adding the base oil and the isocyanate to the mixture of base oil and isocyanate, , Further mixing 10 to 30% by weight of a base oil and an amine-based material.

If the base oil is not mixed and dispersed as described above, problems such as precipitation and lowering of the reason may occur due to nonuniform mixing of the components in the composition.

In one aspect, the mixing of the base oil and the thickener is performed by mixing the base oil and the isocyanate at 40 to 60 ° C, adding the mixture of the base oil and the amine base material, heating and mixing the mixture at 170 to 190 ° C, And a thickener to 50-70 < 0 > C. The temperature is optimized to produce a composition in a stable state, particularly by adding a mixture of the base oil and the amine base material and then heating at 170-190 占 폚 so that carbonization of the components in the composition does not occur, 100% of the iocyanates can react urea.

In one aspect, the mixing step of the present invention may comprise performing under a stirring speed of 40-50 rpm.

The production sequence, temperature and stirring speed in the above production method are optimized for producing the composition of the present invention, and the composition of the present invention can not be stably prepared unless the above conditions are satisfied.

Hereinafter, the constitution and effects of the present invention will be described in more detail with reference to examples and test examples. However, these examples and test examples are provided for illustrative purposes only in order to facilitate understanding of the present invention, and the scope and scope of the present invention are not limited by the following examples.

[Examples] Preparation of composition for constant velocity joint

60% by weight of paraffin oil and 5% by weight of MDI were mixed at a stirring speed of 45 Hz. Then, about 15% by weight of paraffin oil and about 5% by weight of each of methylenediphenyl diisocyanate, octylamine and cyclohexylamine were added to the mixture and stirred at about 180 DEG C at 45 Hz. At this time, the temperature increase rate was maintained at 20 ° C / hr. After using the cooling water and the mixture was cooled to about 60 ℃, and finally, the addition of MoDTC and WS _2, respectively, for 20 ~ 40 minutes. The composition was then homogenized using a 3 roll mill, and homogenization was performed twice to produce a composition (see FIG. 2).

ingredient content base oil Paraffine oil 74.9 wt% thickener MDI + amine 16 wt% additive MoDTC 0.6 wt% WS ₂ (Nano) 5 wt% Antioxidant 3 wt% Corrosion inhibitor 0.5 wt%

[Experimental Example 1] Confirmation of physical properties of composition

The physical properties of the present invention were confirmed based on the criteria shown in Table 2 below (Table 3 and Fig. 1).

Evaluation items
(Main Performance Spec) unit Dimensions As a result of the invention One. Load-proof ( 4 Old fashioned ) kgf ASTM D2596-14 903 2. Abrasion resistance ( 4 Old fashioned ) mm ASTM D2266-01 (2015) 0.43 3. Led 0.1mm ASTM D217-10 285 2. Red dot ℃ KS M ISO 2176: 2003 254 3. Evaporation rate wt% KS M 2037: 1990 0.05 4. Reason map wt% KS M 2050: 1996 0.4

[Experimental Example 2] Confirmation of physical property change according to lubricant

[Experimental Example 2-1] Change according to liner content

The content of WS _2, the lubricant, was controlled to confirm the wear and load-carrying properties (EP) according to the contents. As a result, in the case of the abrasion resistance, it was found that when the content exceeds 8 wt%, the abrasion was increased, and the effect of improving the load resistance was also insignificant (FIG. 3).

[Experimental Example 2-2] Change depending on the type of lubricant

The abrasion resistance and the load-carrying property were confirmed by different types of lubricants, and the results are shown in Table 4 below.

division
result Condition WS ₂ MoS ₂ graphite silica clay EP 1760 rpm, room temperature 400 350 250 80 80 wear 1200 rpm, 75 캜, 40 kg 0.71 0.83 0.87 1.82 0.95

[Experimental Example 3] Confirmation of physical property change according to additive amount

The content of MoDTC was controlled to confirm abrasion resistance and load-bearing property of the composition according to the content thereof. As a result, it was confirmed that when the content of MoDTC was 0.5 to 1.2 wt%, the abrasion resistance was 0.5 mm or less (Fig. 4).

[Experimental Example 4] Confirmation of property change according to content of thickener

[Experimental Example 4-1] Confirmation of lead

The total weight of the thickener was adjusted to confirm the change in the main characteristic. As a result, it was confirmed that a lead of about 265 to 295 suitable for a constant velocity joint can be obtained in a range of about 10 to 20% by weight (FIG. 5).

[Experimental Example 4-2] Confirmation of the reason

The total weight of the thickener was adjusted, and the reason for the change in the properties was confirmed. As a result, it was confirmed that a reason for not more than 3.0 suitable for a constant velocity joint can be obtained in a range of about 11 wt% to 19 wt% (FIG. 6).

[Experimental Example 4-3]

The total weight of the thickener was adjusted to confirm the change in the redness characteristic. As a result, it was confirmed that a reason for a temperature equal to or higher than 240 DEG C suitable for a constant velocity joint could be obtained in a range of about 14 wt% or more (Fig. 7).

[Experimental Example 5] The ellipticity of the thickener according to the stirring temperature

The stirring temperature after mixing the base oil and the thickening agent was controlled, and the degree of ellipticity of the thickening agent according to the temperature was confirmed.

As a result, the thickening of the MDI 2200-2300 ^- when heated to a (cm ¹⁾ N = the MDI in the C = O is there to determine the formation of a strong absorption peak (Fig. 8a), a maximum temperature of 200, 2200 (cm ^{- 1} ), all of the N = C = O peaks disappear, and the urea absorption band of 1500-1700 (cm ^-1 ) strongly appeared, indicating that the MDI reacted with 100% urea (FIG. As a result of the test, it was confirmed that if the heating temperature was lowered to 180, the MDI could be reacted with 100% urea while almost no carbide was generated (FIG. 8C).

[Experimental Example 6] Redox changes according to the content of isocyanate and amine material

The contents of the other components in the composition were kept the same as those in the examples, and only the amine-based materials were controlled, thereby confirming the change in the redness. The content of the amine-based material was expressed based on the molar ratio of the MDI contained in the examples. As a result, it was found that the isocyanate and the amine-based material exhibited the most excellent properties when they were included in the ratio of 1: 2 (Table 5). Even when cyclohexylamine was used as an amine-based material, similar results were obtained as in the case of using octylamine.

MDI One One One One One One One Octylamine 0.1 0.5 One 2 3 5 10 Redness (℃) 220 225 240 245 238 231 220

[Experimental Example 7] Change in Leading Property according to Amine-based Material Composition Ratio

The total amount of the amine-based materials contained in the composition was maintained in the same manner as in the examples, and only the compounding ratio between the amine-based materials was controlled, thereby confirming the change in the luminescence. The molar ratio between the amine-based materials was expressed as a relative value. As a result, it was found that when the octylamine and the cyclohexylamine were contained at a molar ratio of about 1: 1, they exhibited the best lead properties (Table 6).

Octylamine One One One One One One One One Cyclohexylamine 0.1 0.5 0.8 One 1.2 3 5 10 lead 255 260 280 285 282 260 255 250

[Experimental Example 8] Comparison of properties according to the size of the lubricant

The properties of commercially available grease compositions including micrometer lubricants and compositions of the present invention compositions were compared. As a result, it was confirmed that when the nano-level lubricant was used as in the composition of the present invention, the load resistance and wear resistance properties were superior to those of the conventional lubricant containing micrometer-level lubricants (Table 7).

Item Existing CV-Joint Grease Example composition Load-bearing characteristics 400 kgf 490 kgf Wear resistance characteristic 0.6 mm 0.43 mm

Claims (16)

A grease composition for constant velocity joint,
The composition may comprise a base oil; Thickener; And a lubricant,
Wherein the thickener comprises an isocyanate and an amine-based material,
Wherein the isocyanate and the amine-based material are contained in a molar ratio of 1: 0.5 to 5, respectively. The method according to claim 1,
Wherein said isocyanate comprises methylene diphenyl diisocyanate. ≪ RTI ID = 0.0 > 8. < / RTI > The method according to claim 1,
The amine-
Octylamine; And cyclohexylamine. ≪ Desc / Clms Page number 24 > The method of claim 3,
The octylamine and cyclohexylamine may be,
Wherein the molar ratio is 1: 0.5 to 5, respectively. The method according to claim 1,
Wherein the lubricant comprises a solid lubricant having an average diameter of 0.1 to 900 nm. The method according to claim 1,
Wherein the lubricant is molybdenum disulfide or tungsten disulfide. The method according to claim 1,
The composition further comprises an additive,
Wherein the additive comprises molybdenum di thiocarbamate (MoDTC). The method according to claim 1,
The base oil includes a paraffin oil. The method according to claim 1,
The composition, based on the total weight of the composition,
70 to 80% by weight of base oil; 10 to 20% by weight thickener; And 1 to 10% by weight of a lubricant. 8. The method of claim 7,
Wherein the additive is included in an amount of 0.1 to 1% by weight based on the total weight of the composition. The method according to claim 1,
Said composition comprising at least one of the following properties:
1) a luminescence value measured at 25 占 폚 according to ASTM D217-10 of not less than 240;
2) The measured point according to KS M ISO 2176: 2003 is 265 ~ 295 ℃;
3) Abrasion resistance measured according to ASTM D2266-01 (2015) of not more than 0.5;
4) Load resistance of 500 or more as measured according to ASTM D2596-14;
5) Reasonable degree measured at 100 ℃ according to KS M ISO 2050: 1996 is less than 3.0; And
6) The evaporation amount measured according to KS M ISO 2037: 1990 is less than 0.5. A method of producing a grease composition for a constant velocity joint according to any one of claims 1 to 11,
The method comprises the steps of: Thickener; Lubricant; And mixing the additive with the additive. 13. The method of claim 12,
Wherein said mixing step comprises the following steps:
1) mixing a base oil and a thickener; And
2) mixing the lubricant and additive in a mixture of base oil and thickener. 14. The method of claim 13,
Mixing the base oil and the thickener,
Based on the total weight of the base oil in the composition, 70 to 90% by weight of base oil and isocyanate are mixed,
Further comprising adding 10 to 30% by weight of a base oil and an amine-based material to the mixture of the base oil and the isocyanate, based on the total weight of the base oil in the composition. 15. The method of claim 14,
The base oil and the thickener are mixed by mixing the base oil and the isocyanate at 40 to 60 ° C, adding a mixture of base oil and amine base material, heating and mixing the mixture at 170 to 190 ° C, To < RTI ID = 0.0 > 70 C. < / RTI > 13. The method of claim 12,
Wherein the mixing step is performed at a stirring speed of 40 to 50 rpm.

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