A grease composition for a cross universal joint and a preparation method thereof

Abstract

The present invention relates to the field of lubrication technology, and particularly to a grease composition for a cross universal joint and a preparation method thereof. The grease composition comprises the following components: base oil, isocyanate, organic amine, anti-friction agent, extreme pressure agent, and rust inhibitor. The grease composition has excellent extreme pressure performance and durability, and at the same time has excellent high temperature resistance, and the service temperature can reach -30 to 180 °C, which can meet the lubrication requirements of cross universal joints of medium and heavy commercial vehicles.

Description

Technical Field

[0001] The present invention relates to the technical field of lubrication, and particularly relates to a grease composition for a cross universal joint and a preparation method thereof. Background Art

[0002] The cross universal shaft, also known as the cross universal joint, is one of the very important transmission devices in vehicles or other mechanical equipment. It is mainly used to connect the power transmitted by the vehicle engine and the power of the wheels or other working mechanisms, enabling them to rotate at different angles and directions. In modern transportation vehicles and mechanical equipment, the cross universal shaft plays a crucial role, which can greatly improve the mechanical transmission efficiency and safety.

[0003] The cross universal shaft is mainly used in the transmission mechanism of mechanical equipment such as vehicles, and can transmit the power from the engine to working mechanisms such as wheels. During the driving process of a vehicle, the angle and position between the wheels and the vehicle body usually change, which requires the cross universal shaft to span these changes in angles and directions to ensure stable power transmission between the wheels and the vehicle body. Therefore, the cross universal shaft plays a very important role in the vehicle transmission mechanism, which can greatly improve the driving efficiency and safety of the vehicle under different road conditions.

[0004] The universal joints used in medium and heavy commercial vehicles are mainly cross shaft type universal joints. The cross shaft type universal joint mainly consists of a driving fork, a driven fork, a cross shaft, a needle roller bearing and its axial positioning parts, rubber seals, etc. The automotive drive shaft consists of a universal joint, a shaft tube, and its telescopic spline, etc., where the universal joint is the core component of the drive shaft. The damage of the cross shaft universal joint is mainly the wear of the cross shaft journal and the needle roller bearing, the indentation and spalling of the working surfaces of the cross shaft journal and the needle roller bearing bowl. Good lubrication can reduce the wear of the universal joint and prevent the early damage of the cross shaft and the needle roller. The lubrication effect of the needle roller bearing directly affects the service life of the universal joint. The internal temperature rise of the cross shaft type universal joint of medium and heavy commercial vehicles is relatively high at high speeds, so the grease is required to have good high-temperature performance. At the same time, the cross shaft type universal joint of commercial vehicles bears a large torque and impact load, so the grease is required to have good extreme pressure and anti-wear performance. At the same time, the cross shaft is generally located under the vehicle chassis and is easily eroded by water vapor, so certain anti-corrosion performance is required. Summary of the Invention

[0005] The present invention aims to solve at least one of the above technical problems.

[0006] The present invention provides a grease composition for a cross universal joint and a preparation method thereof, which are applicable to medium and heavy commercial vehicles. The grease composition for the cross universal joint provided by the present invention has excellent high-temperature and extreme pressure anti-wear properties, and at the same time has good anti-corrosion properties, and can significantly improve the lubrication performance of the cross shaft type universal joint of medium and heavy commercial vehicles and extend its service life.

[0007] A grease composition, by weight percentage, comprises the following components:

[0008]

[0009] According to some preferred embodiments of the present invention, the grease composition, by weight percentage, comprises the following components:

[0010]

[0011] According to some embodiments of the present invention, the grease composition is made up to a total of 100% with base oil.

[0012] According to some embodiments of the present invention, the grease composition is composed of or made from the above components.

[0013] According to some preferred embodiments of the present invention, the base oil is at least one of mineral oil and poly-α-olefin synthetic oil; the kinematic viscosity of the base oil at 40 °C is 200 - 450 mm 2 / s, the viscosity index is not less than 90, and the pour point is not higher than -10 °C.

[0014] According to some preferred embodiments of the present invention, the viscosity index of the base oil is 90 - 110.

[0015] According to some preferred embodiments of the present invention, the pour point of the base oil is -20 to -10 °C.

[0016] According to some preferred embodiments of the present invention, the isocyanate is diphenylmethane - 4,4 - diisocyanate.

[0017] According to some preferred embodiments of the present invention, the organic amine is at least one of n-octylamine, dodecyl primary amine, octadecyl primary amine, cyclohexylamine, aniline, and p-toluidine.

[0018] It has been found that using the above reaction product of isocyanate and organic amine as a urea thickener has excellent high-temperature performance and can significantly improve the high-temperature and extreme-pressure anti-wear properties, as well as the corrosion resistance of the grease composition.

[0019] According to some specific embodiments of the present invention, the organic amine is a combination of octadecyl primary amine and cyclohexylamine, for example, the weight ratio of the two is 32:108.

[0020] According to some specific embodiments of the present invention, the organic amine is a combination of octadecyl primary amine and n-octylamine, for example, the weight ratio of the two is 109:52.

[0021] According to some specific embodiments of the present invention, the organic amine is a combination of cyclohexylamine and aniline, for example, the weight ratio of the two is 103:97.

[0022] According to some specific embodiments of the present invention, the organic amine is a combination of octadecylamine and dodecylamine. For example, the weight ratio of the two is 26:89.

[0023] According to some preferred embodiments of the present invention, based on the total weight of the grease composition, the sum of the weights of the isocyanate and the organic amine is 7.5 - 15.5%, and may be 7.8 - 15.3%.

[0024] According to some preferred embodiments of the present invention, the antiwear agent is a combination of at least one of molybdenum dialkyldithiocarbamate and molybdenum dialkyldithiophosphate and an organic molybdenum amine complex.

[0025] According to some specific embodiments of the present invention, the antiwear agent is a combination of molybdenum dialkyldithiocarbamate and an organic molybdenum amine complex. For example, the weight ratio of the two is 1:1.

[0026] According to some specific embodiments of the present invention, the antiwear agent is a combination of molybdenum dialkyldithiocarbamate, molybdenum dialkyldithiophosphate and an organic molybdenum amine complex. For example, the weight ratio of the three is 1:1:1 or 1:1:2.

[0027] According to some preferred embodiments of the present invention, the extreme pressure agent is selected from at least one of borate and melamine cyanurate complex.

[0028] According to specific preferred embodiments of the present invention, the extreme pressure agent is a combination of borate and melamine cyanurate complex. For example, the weight ratio of the two is 1:1.

[0029] According to some preferred embodiments of the present invention, the rust inhibitor is selected from at least one of benzotriazole, barium dinonylnaphthalenesulfonate, and calcium sulfonate.

[0030] It has been found that by selecting the above base oil, thickener and extreme pressure agent in combination, the high-temperature and extreme pressure antiwear properties and corrosion resistance of the grease composition can be significantly improved, and it is particularly suitable as a grease for a cross universal joint.

[0031] The present invention also provides a method for preparing the above grease composition, including: mixing the organic amine, isocyanate and part of the base oil, then heating the mixed material for saponification, the heating temperature is 145 - 185 °C, and then adding the remaining base oil to thicken, cooling to below 110 °C, adding the antiwear agent, extreme pressure agent and rust inhibitor, and obtaining the product after mixing evenly and post-treatment.

[0032] The thickener prepared by the reaction of the diisocyanate and the organic amine used in the grease composition of the present invention has excellent high-temperature performance, and the service temperature can reach -30 to 180 °C; the use of at least one of borate and melamine cyanurate complex in combination with an organic molybdenum salt antiwear agent can achieve good extreme pressure and antiwear performance, which is particularly suitable for lubricating the cross-axis universal joints of medium and heavy commercial vehicles and extending the service life of the cross-axis universal joints. The rust inhibitor is selected from at least one of benzotriazole, barium dinonylnaphthalene sulfonate, and calcium sulfonate, which can have good corrosion resistance and ensure the good use of the cross-axis universal joints of medium and heavy commercial vehicles under conditions such as humidity and wading. Detailed Embodiments

[0033] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention. For those not specifying specific techniques or conditions in the examples, the techniques or conditions described in the literature in the art are followed, or the product specifications are followed.

[0034] In the present invention, for those instruments etc. without indicating the manufacturer, they are all conventional products that can be obtained through regular channels. The raw materials used in the present invention can be conveniently purchased in the domestic product market.

[0035] Example 1

[0036] The raw material formula of the grease composition in this example:

[0037] Base oil 2500 g;

[0038] Diphenylmethane - 4,4 - diisocyanate 150 g;

[0039] Octadecylamine 32 g;

[0040] Cyclohexylamine 108 g;

[0041] Dialkyldithiocarbamate molybdenum 30 g;

[0042] Organic molybdenum amine complex 30 g;

[0043] Borate 90 g;

[0044] Barium dinonylnaphthalene sulfonate 60 g;

[0045] The base oil in this example is mineral oil, with a kinematic viscosity at 40 °C of 430 mm 2 / s, a viscosity index of 95, and a pour point of -15 °C.

[0046] The preparation method of the grease composition in this example:

[0047] Add diphenylmethane - 4,4 - diisocyanate into a reaction vessel, and at the same time add 1530 mineral oil; add octadecylamine and cyclohexylamine into another vessel, and at the same time add 470 g of mineral oil; heat the two vessels to 70 °C respectively. After keeping the temperature constant for 10 min, put the materials in the two vessels into the reaction kettle, keep the temperature constant and time the reaction for 40 ± 5 min, and then slowly heat up to the maximum refining temperature of 150 °C between 1.5 h and 2 h. After heating up to the maximum refining temperature, add 500 g of mineral oil and cool it. Then switch the heat transfer oil in the reaction kettle for cooling. After cooling down to below 80 °C, add the anti - friction agent molybdenum dialkyldithiocarbamate and organic molybdenum - amine complex, add the extreme - pressure agent borate, and then add the rust inhibitor barium dinonylnaphthalene sulfonate. After stirring evenly, carry out post - treatments such as dispersion and degassing. After the consistency is qualified, can the finished product.

[0048] Example 2

[0049] The raw material formula of the grease composition in this example:

[0050] Base oil 2493 g;

[0051] Diphenylmethane - 4,4 - diisocyanate 100 g;

[0052] Octadecylamine 109 g;

[0053] n - Octylamine 52 g;

[0054] Molybdenum dialkyldithiocarbamate 30 g;

[0055] Organic molybdenum - amine complex 30 g;

[0056] Melamine urate complex 60 g;

[0057] Borate 60 g;

[0058] Benzotriazole 6 g;

[0059] Calcium sulfonate 60 g.

[0060] The base oil in this example is mineral oil and polyalpha - olefin synthetic oil, with a kinematic viscosity at 40 °C of 220 mm 2 / s, a viscosity index of 105, and a pour point of - 18 °C.

[0061] The preparation method of the grease composition in this example:

[0062] Add diphenylmethane-4,4-diisocyanate into a reaction vessel, and at the same time add 1600 g of mineral oil; add octadecylamine and n-octylamine into another vessel, and at the same time add 400 g of poly-α-olefin synthetic base oil. Heat the two vessels to 75 °C respectively. After keeping the temperature constant for 10 min, put the materials in the two vessels into the reaction kettle, keep the temperature constant and time the reaction for 45 ± 5 min. Then slowly heat up to the maximum refining temperature of 165 °C between 1.5 h and 2 h. After heating up to the maximum refining temperature, add 493 g of mineral oil for cooling. Then switch the heat transfer oil in the reaction kettle for cooling. After cooling down to below 80 °C, add the antiwear agent molybdenum dialkyldithiocarbamate and organic molybdenum amine complex, add the extreme pressure agent melamine cyanurate complex and borate, and finally add the rust inhibitor benzotriazole and calcium sulfonate. After stirring evenly, carry out post-treatment such as dispersion and degassing. After the consistency is qualified, can the finished product.

[0063] Example 3

[0064] The raw material formula of the grease composition in this example:

[0065] Base oil 2265 g;

[0066] Diphenylmethane-4,4-diisocyanate 260 g;

[0067] Cyclohexylamine 103 g;

[0068] Aniline 97 g;

[0069] Molybdenum dialkyldithiocarbamate 30 g;

[0070] Molybdenum dialkyldithiophosphate 30 g;

[0071] Organic molybdenum amine complex 30 g;

[0072] Borate 60 g;

[0073] Melamine cyanurate complex 60 g;

[0074] Benzotriazole 6 g;

[0075] Barium dinonylnaphthalene sulfonate 30 g;

[0076] Calcium sulfonate 30 g.

[0077] The base oil in this example is mineral oil, the kinematic viscosity at 40 °C is 300 mm 2 / s, the viscosity index is 110, and the pour point is -20 °C.

[0078] The preparation method of the grease composition in this example:

[0079] Add diphenylmethane - 4,4 - diisocyanate into a reaction vessel, and at the same time add 1500 g of mineral oil; in another vessel, add cyclohexylamine and aniline, and at the same time add 500 g of mineral oil; heat the two vessels to 75 °C, keep the temperature constant for 10 min, then put the materials in the two vessels into the reaction kettle, keep the temperature constant and start timing the reaction for 45 ± 5 min, and then slowly heat up to the highest refining temperature of 163 °C between 1.5 h and 2 h. After heating up to the highest refining temperature, add 265 g of mineral oil for cooling, and then switch the heat transfer oil in the reaction kettle for cooling. After cooling down to below 80 °C, add anti - friction agents molybdenum dialkyldithiocarbamate, molybdenum dialkyldithiophosphate, and organic molybdenum amine complex, add extreme pressure agents borate and melamine cyanurate complex, and finally add rust inhibitors benzotriazole, barium dinonylnaphthalene sulfonate, and calcium sulfonate. After stirring evenly, carry out post - treatments such as dispersion and degassing. After the consistency is qualified, can the finished product.

[0080] Example 4

[0081] The raw material formula of the grease composition in this example:

[0082] Base oil 2555 g;

[0083] Diphenylmethane - 4,4 - diisocyanate 120 g;

[0084] Octadecylamine 26 g;

[0085] Dodecylamine 89 g;

[0086] Molybdenum dialkyldithiocarbamate 15 g;

[0087] Molybdenum dialkyldithiophosphate 15 g

[0088] Organic molybdenum amine complex 30 g;

[0089] Melamine cyanurate complex 120 g;

[0090] Barium dinonylnaphthalene sulfonate 30 g.

[0091] The base oil in this example is mineral oil and poly - α - olefin synthetic oil, the kinematic viscosity at 40 °C is 450 mm 2 / s, the viscosity index is 105, and the pour point is - 17 °C.

[0092] The preparation method of the grease composition in this example:

[0093] Diphenylmethane - 4,4 - diisocyanate is added into a reaction vessel, and 1500 g of mineral oil is added simultaneously; in another vessel, octadecylamine and dodecylamine are added, and 555 g of mineral oil is added at the same time. The two vessels are each heated to 85 °C and kept at a constant temperature for 10 min. Then the materials in the two vessels are put into a reaction kettle, and the reaction is carried out at a constant temperature for 45 ± 5 min. After that, the temperature is slowly raised to the maximum refining temperature of 175 °C within 1.5 h. After the temperature is raised to the maximum refining temperature, 500 g of poly-α-olefin synthetic oil is added for cooling. Then the heat transfer oil in the reaction kettle is switched for cooling. After the temperature is lowered to below 80 °C, antiwear agents such as molybdenum dialkyldithiocarbamate, molybdenum dialkyldithiophosphate, and organic molybdenum amine complex are added, extreme pressure agent melamine cyanurate complex is added, and finally rust inhibitor barium dinonylnaphthalene sulfonate is added. After stirring evenly, post-treatments such as dispersion and degassing are carried out, and the product is canned after the consistency is qualified.

[0094] Comparative Example 1

[0095] This comparative example provides a grease composition. The kinematic viscosity of the mineral oil used at 40 °C is 90 mm 2 / s, the viscosity index is 80, and the pour point is -5 °C. The specific preparation method is as follows:

[0096] 257 g of 12 - hydroxystearic acid and 2000 g of mineral oil are put into a reaction kettle and heated; when the temperature of the reaction kettle rises to 80 °C, an aqueous solution of 43 g of lithium hydroxide monohydrate is added to the reaction kettle for saponification reaction; after the saponification is completed, the temperature is continued to rise. After the temperature rises to 200 °C, it is kept at a constant temperature for 7 minutes, and 535 g of mineral oil is added to the reaction kettle to cool the materials. Then the temperature is lowered naturally. When the temperature is lowered to below 80 °C, 30 g of molybdenum dialkyldithiophosphate and 30 g of molybdenum dialkyldithiophosphate as antiwear agents are added, 15 g of thioisobutene and 60 g of melamine cyanurate complex as extreme pressure agents are added, and finally 30 g of barium dinonylnaphthalene sulfonate is added. After stirring evenly, post-treatments such as dispersion and degassing are carried out, and the product is canned after the consistency is qualified.

[0097] Comparative Example 2

[0098] This comparative example provides a grease composition. The kinematic viscosity of the mineral oil used at 40 °C is 50 mm 2 / s, the viscosity index is 70, and the pour point is -5 °C. The specific preparation method is as follows:

[0099] Put 257 g of 12 - hydroxy stearic acid and 2000 g of mineral oil into the reaction kettle and heat it up; when the temperature of the reaction kettle rises to 80 °C, add an aqueous solution of 43 g of lithium hydroxide monohydrate to the reaction kettle for saponification reaction; after the saponification is completed, continue to heat up, when the temperature rises to 200 °C, keep it at a constant temperature for 7 minutes, add 200 g of poly - α - olefin synthetic oil and 434 g of mineral oil to the reaction kettle to cool the material, then let it cool naturally, when the temperature drops below 80 °C, add 30 g of extreme pressure agent isobutene sulfide, and finally add 6 g of rust inhibitor benzotriazole and 30 g of calcium sulfonate, stir evenly and then carry out post - treatments such as dispersion and degassing, and can the finished product after the consistency is qualified.

[0100] Comparative Example 3

[0101] This comparative example provides a grease composition, and the kinematic viscosity of the mineral oil used at 40 °C is 430 mm 2 / s, the viscosity index is 95, and the pour point is - 15 °C. The specific preparation method is as follows:

[0102] Add 150 g of diphenylmethane - 4,4 - diisocyanate to a reaction vessel, and at the same time add 1530 g of mineral oil; add 32 g of octadecylamine and 108 g of cyclohexylamine to another container, and at the same time add 470 g of mineral oil; heat the two containers to 70 °C respectively, after keeping at a constant temperature for 10 min, put the materials of the two containers into the reaction kettle, keep at a constant temperature and time for reaction for 40 ± 5 min, and then slowly heat up to the highest refining temperature of 150 °C between 1.5 h and 2 h. After heating up to the highest refining temperature, add 500 g of mineral oil, carry out cooling, then switch the heat - conducting oil in the reaction kettle for cooling and temperature reduction, after the temperature drops below 80 °C, add 30 g of anti - friction agent molybdenum dialkyldithiocarbamate and 30 g of organic molybdenum amine complex, add 90 g of extreme pressure agent isobutene sulfide, and then add 60 g of rust inhibitor barium dinonylnaphthalene sulfonate, stir evenly and then carry out post - treatments such as dispersion and degassing, and can the finished product after the consistency is qualified.

[0103] Comparative Example 4

[0104] This comparative example provides a grease composition, and the kinematic viscosity of the mineral oil used at 40 °C is 430 mm 2 / s, the viscosity index is 95, and the pour point is - 15 °C. The specific preparation method is as follows:

[0105] Add 150 g of diphenylmethane - 4,4 - diisocyanate into a reaction vessel, and at the same time add 1590 g of mineral oil; add 32 g of octadecylamine and 108 g of cyclohexylamine into another vessel, and at the same time add 470 g of mineral oil; heat the two vessels to 70 °C, keep the temperature constant for 10 min, then put the materials in the two vessels into the reaction kettle, keep the temperature constant and time the reaction for 40 ± 5 min, and then slowly heat up to the maximum refining temperature of 150 °C between 1.5 h and 2 h. After heating up to the maximum refining temperature, add 500 g of mineral oil, and then conduct cooling. After that, switch the heat - conducting oil in the reaction kettle for cooling and temperature reduction. After the temperature drops below 80 °C, add 60 g of anti - friction agent sulfonated cottonseed oil, add 30 g of extreme - pressure agent sulfonated isobutene, and then add 60 g of rust inhibitor zinc sulfonate. After stirring evenly, conduct post - treatments such as dispersion and degassing. After the consistency is qualified, can the finished product.

[0106] Table 1 Composition of Greases in Examples 1 - 4 and Comparative Examples 1 - 4

[0107]

[0108]

[0109] Since the dropping point of the grease can reflect the high - temperature performance of the grease; the four - ball extreme - pressure performance reflects the extreme - pressure performance of the grease; the four - ball anti - wear performance reflects the anti - wear performance of the grease; and the anti - corrosion property reflects the rust - prevention performance of the grease. Therefore, the dropping point, four - ball extreme - pressure, four - ball anti - wear, anti - corrosion, etc. tests and comparisons were respectively carried out on the examples and comparative examples of the present invention. The test results of the greases obtained from Examples 1 - 4 and Comparative Examples 1 - 4 are shown in Table 2.

[0110] Table 2 Test Results of Performance of Examples and Comparative Examples

[0111]

[0112]

[0113] Although the present invention has been described in detail with general descriptions and specific embodiments above, based on the present invention, some modifications or improvements can be made, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection required by the present invention.

Claims

1. Application of a grease composition in lubricating a cross universal joint, characterized in that, By weight percentage, it contains the following components: Isocyanate 3 - 9%; Organic amine 3.5 - 7%; Anti-wear agent 1.5 - 3.5%; Extreme pressure agent 2.5 - 6%; Rust inhibitor 1.5 - 3%; Base oil 80 - 90%; The sum of the weight percentages of the above components is 100%; The base oil is at least one of mineral oil and polyalphaolefin synthetic oil; the kinematic viscosity of the base oil at 40 °C is 200 to 450 mm 2 / s, the viscosity index is not less than 90, and the pour point is not higher than -10 °C; The extreme pressure agent is selected from at least one of borate and melamine cyanurate complex; The anti-wear agent is a combination of at least one of molybdenum dialkyldithiocarbamate and molybdenum dialkyldithiophosphate and an organic molybdenum amine complex; The rust inhibitor is selected from at least one of benzotriazole, barium dinonylnaphthalene sulfonate, and calcium sulfonate.

2. The application according to claim 1, wherein The grease composition, by weight percentage, contains the following components: Isocyanate 3.3 - 8.6%; Organic amine 3.8 - 6.7%; Anti-wear agent 2 - 3%; Extreme pressure agent 3 - 4%; Rust inhibitor 2 - 2.2%; Base oil 83 - 85.5%; The sum of the weight percentages of the above components is 100%.

3. The application according to claim 2, characterized in that The viscosity index of the base oil is 90 - 110; and / or, the pour point of the base oil is -20 to -10 °C.

4. The application according to claim 3, characterized in that, The isocyanate is diphenylmethane - 4,4 - diisocyanate.

5. The application according to claim 4, characterized in that, The organic amine is at least one of n-octylamine, dodecyl primary amine, octadecyl primary amine, cyclohexylamine, aniline, and p-toluidine.

6. The preparation method of the grease composition in the application according to any one of claims 1-5, characterized in that, It includes the following steps: Mix the organic amine, isocyanate with part of the base oil, then heat up the mixed material for saponification, the heating temperature is 145 - 185 °C, then add the remaining base oil to thicken, cool down to below 110 °C, add the anti-wear agent, extreme pressure agent and rust inhibitor, and obtain the product after mixing evenly and post-treatment.

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