Multicomponent synergistically modified greases and methods for making the same

Abstract

This invention relates to the field of lubricating materials technology, and particularly to a multi-component synergistic modified grease and its preparation method. The multi-component synergistic modified grease, by weight, comprises the following raw materials: a thickener, a molybdenum-based composite additive, and a first base oil, totaling 100 parts, wherein the thickener comprises 25.0–75.0 parts, and the molybdenum-based composite additive comprises 2.0–8.0 parts; the molybdenum-based composite additive includes nano-molybdenum disulfide (MoS2), molybdenum dialkyldithiocarbamate (MoDTC), and ammonium 3-butyl-4-methyl-5-vinylthiazolyl molybdate. This multi-component synergistic modified grease, by synergistically combining multiple molybdenum-based additives and using a thickener, overcomes the limitations of existing technologies that rely on single or two molybdenum-based additives, significantly improving the grease's super-lubricating properties, anti-wear properties, and long-term stability.

Description

Technical Field

[0001] This invention relates to the field of lubricating materials technology, and in particular to a multi-component synergistic modified grease and its preparation method. Background Technology

[0002] As a key protective material for friction pairs in mechanical equipment, grease's lubrication performance, extreme pressure anti-wear properties, and high and low temperature stability directly determine the equipment's operating efficiency, service life, and safety. With the development of industrial equipment towards higher speeds, heavier loads, greater precision, and environmental friendliness, higher demands are placed on the super-lubricating properties of grease (low coefficient of friction, low wear), especially in harsh operating conditions such as automotive transmission systems, precision machine tools, and construction machinery, where traditional greases can no longer meet the requirements for long-term stable lubrication.

[0003] Molybdenum-based additives are widely used in grease formulations due to their excellent friction-reducing, anti-wear, extreme pressure, and anti-oxidation properties. Common molybdenum-based additives include molybdenum disulfide (MoS2), molybdenum dialkyldithiocarbamate (MoDTC), molybdenum dialkyldithiophosphate (MoDTP), and organic molybdenum ionic liquids. In existing technologies, molybdenum-based greases often use a single molybdenum-based additive or a simple mixture of two molybdenum-based components, which has the following drawbacks: First, the performance of a single molybdenum-based additive is limited. For example, MoS2 is prone to oxidation and failure under high temperature and humidity conditions, MoDTC has insufficient lubrication durability under extreme pressure conditions, and organic molybdenum ionic liquids have poor dispersibility when used alone. Second, the mixing ratio of different molybdenum-based additives lacks scientific design, the synergistic effect between components is not fully utilized, and even performance antagonism occurs, making it difficult to balance the grease's super-lubricating properties, high and low temperature adaptability, and service life. Third, existing molybdenum-based grease preparation processes often use direct mixing methods, resulting in uneven additive dispersion, further affecting the stability of lubrication performance.

[0004] For example, patent CN114302941A discloses a grease composition containing zinc sulfide, molybdenum disulfide, and / or tungsten disulfide, primarily used in constant velocity universal joints. While it uses molybdenum disulfide as a solid lubricant, it simply combines it with zinc sulfide without considering the synergistic design of multiple molybdenum-based additives, resulting in insufficient lubrication performance. Patent CN117946026A discloses an organic molybdenum ionic liquid grease extreme pressure anti-wear additive, focusing only on the preparation and application of a single organic molybdenum ionic liquid without synergistic use with other molybdenum-based additives, making it difficult to meet the ultra-lubricating requirements under complex working conditions. Patent CN119144379A achieves ultra-lubricity, but uses β-diketone compounds and does not involve innovative combinations of molybdenum-based additives. Therefore, developing a grease based on innovative mixing and scientific proportioning of molybdenum-based additives, possessing ultra-lubricating properties, extreme pressure anti-wear properties, and long-term stability, has become an urgent need in the current lubrication materials field. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a multi-component synergistic modified grease and its preparation method, which aims to solve the problems of insufficient super-lubricating performance, poor adaptability to working conditions, and short service life of existing molybdenum-based greases.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: The first aspect of this invention provides a multi-component synergistic modified grease, the raw materials for its preparation comprising, by weight, 100 parts of thickener, molybdenum-based composite additive and first base oil, wherein the thickener comprises 25.0 to 75.0 parts and the molybdenum-based composite additive comprises 2.0 to 8.0 parts. The molybdenum-based composite additives include nano-molybdenum disulfide (MoS2), molybdenum dialkyl dithiocarbamate (MoDTC), and ammonium 3-butyl-4-methyl-5-vinylthiazolyl molybdate.

[0007] The multi-component synergistic modified grease wherein the weight ratio of the nano-molybdenum disulfide (MoS2), molybdenum dialkyl dithiocarbamate (MoDTC) and ammonium 3-butyl-4-methyl-5-vinylthiazolyl molybdate is (2.5-4.5):(3.0-5.0):(1.0-3.0).

[0008] The multi-component synergistic modified grease, wherein the first base oil comprises paraffinic mineral oil and polyalphaolefin in a mass ratio of (70-80):(20-30).

[0009] The multi-component synergistic modified grease, wherein the thickener is a lithium complex soap with a saponification degree of 92% to 96%.

[0010] The multi-component synergistic modified grease is wherein the lithium complex soap is prepared by saponification reaction of a second base oil, 12-hydroxystearic acid, sebacic acid and lithium hydroxide.

[0011] The multi-component synergistic modified grease, wherein the preparation method of the lithium composite soap includes the following steps: 12-hydroxystearic acid and sebacic acid are mixed in a weight ratio of (7-10):(1-5), added to a reaction apparatus, and then a second base oil is added, the weight of which is 3-5 times the total weight of 12-hydroxystearic acid and sebacic acid. The temperature is raised to 85-95°C and stirred until completely dissolved. Subsequently, an 8.0-15.0% lithium hydroxide aqueous solution is slowly added, the temperature is raised to 110-130°C, and the saponification reaction is maintained for 60-90 minutes. During the saponification reaction, the mixture is continuously stirred to obtain a lithium composite soap thickener.

[0012] The multi-component synergistic modified grease, wherein the preparation method of the molybdenum dialkyldithiocarbamate includes the following steps: mixing and stirring a hexavalent molybdenum source, a dialkyl secondary amine, and pure water, adding carbon disulfide dropwise, and reacting the mixture at 65-95°C for 5-7 hours; adding a solvent and extracting at 20-60°C for 2-8 hours, separating the upper oil phase, and obtaining the molybdenum dialkyldithiocarbamate by filtration and reduced evaporation.

[0013] The multi-component synergistic modified grease, wherein the hexavalent molybdenum source includes at least one of molybdenum trioxide, sodium molybdate, and ammonium molybdate; and the dialkyl secondary amine includes at least one of dipentylamine, diisooctylamine, and 2-n-octyl-1-dodecylamine.

[0014] The multi-component synergistic modified grease, wherein the particle size of the nano-molybdenum disulfide is 50-200 nm.

[0015] A second aspect of the present invention provides a multi-component synergistic modified grease, comprising the following steps: S1. Nano molybdenum disulfide, molybdenum dialkyldithiocarbamate and ammonium 3-butyl-4-methyl-5-vinylthiazolyl molybdate are mixed to obtain a uniformly dispersed molybdenum-based composite additive precursor. S2. Add the thickener to the first base oil, control the temperature at 140-160℃, stir at 800-1200 r / min, keep stirring at the temperature for 30-60 minutes to fully blend and form a uniform grease base system; S3. Slowly add the molybdenum-based composite additive precursor into the grease base system, control the temperature at 110-130℃, the stirring speed at 1200-1500 r / min, and keep it at this temperature for 30-60 min to ensure thorough dispersion; S4. Grind the obtained mixture to remove impurities and agglomerated particles; allow the ground mixture to cool naturally to room temperature to obtain the multi-component synergistic modified grease as described above.

[0016] Beneficial Effects: This invention provides a multi-component synergistic modified grease. Through an innovative blend and precise proportioning design of three molybdenum-based additives, this grease fully leverages the synergistic effects of its components, addressing the problems of insufficient super-lubricating properties, poor adaptability to operating conditions, and short service life in existing molybdenum-based greases. It achieves long-term stable super-lubricating lubrication under high temperature, heavy load, and complex environments. Furthermore, this invention uses a thickener to encapsulate the base oil and molybdenum-based composite additives, forming a stable grease structure, preventing additive sedimentation, and solving the problem of unstable dispersion. Detailed Implementation

[0017] This invention provides a multi-component synergistic modified grease and its preparation method. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the following embodiments are provided to further illustrate the invention in detail. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0018] The first aspect of this invention provides a multi-component synergistic modified grease, the raw materials for its preparation comprising, by weight, 100 parts of thickener, molybdenum-based composite additive and a first base oil, wherein the thickener comprises 25.0 to 75.0 parts and the molybdenum-based composite additive comprises 2.0 to 8.0 parts; the molybdenum-based composite additive comprises nano-molybdenum disulfide (MoS2), molybdenum dialkyl dithiocarbamate (MoDTC) and ammonium 3-butyl-4-methyl-5-vinylthiazolyl molybdate.

[0019] In the molybdenum-based composite additive, the layered structure of nano-molybdenum disulfide (MoS2) can form a lubricating film on the surface of the friction pair, exerting a physical friction-reducing effect; molybdenum dialkyldithiocarbamate (MoDTC) is an oil-soluble additive that can undergo a chemical reaction during friction to generate a MoS2 lubricating film, enhancing extreme pressure anti-wear performance; 3-butyl-4-methyl-5-vinylthiazolylmolybdate ammonium salt is an ionic additive, phosphorus-free, environmentally friendly, and possesses good dispersibility and antioxidant properties, which can synergistically improve the super-lubricating performance and long-term stability of the grease. The synergistic effect of the three additives overcomes the performance limitations of single molybdenum-based additives, achieving multiple functions of physical lubrication, chemical lubrication, and dispersion stability. Through the synergistic effect of multiple molybdenum-based additives, the coefficient of friction of the grease can be reduced to about 0.05, and the tested wear scar diameter is ≤0.40mm. Compared with greases with single molybdenum-based additives, the super-lubricating performance is significantly improved, which can effectively reduce equipment friction and wear and reduce energy consumption.

[0020] Furthermore, the multi-component synergistic modified grease of the present invention has a wide range of working conditions, can work stably at high temperatures, and has excellent antioxidant properties; at the same time, it has excellent anti-wear and anti-corrosion properties, and can be adapted to various harsh working conditions such as automotive constant velocity universal joints, precision machine tool spindles, engineering machinery sliding bearings, and rolling guides, solving the problem of unstable performance of existing greases under complex working conditions.

[0021] The multi-component synergistic modified grease of the present invention also has excellent storage stability. After 60 days of storage, the rate of change of friction coefficient and the rate of change of wear scar diameter are low, which is better than existing molybdenum-based greases. At the same time, the addition of organic molybdenum ionic liquid improves the antioxidant properties of the grease, extends the service life of the grease, reduces the frequency of grease replacement, and reduces equipment maintenance costs.

[0022] Preferably, the weight ratio of the nano-molybdenum disulfide (MoS2), molybdenum dialkyldithiocarbamate (MoDTC), and ammonium 3-butyl-4-methyl-5-vinylthiazolylmolybdate is (2.5–4.5):(3.0–5.0):(1.0–3.0). This ratio maximizes the synergistic effect between the components, avoids performance antagonism between components, and solves the problem of unreasonable mixing ratios of molybdenum-based additives in the prior art. The proportion of the organic molybdenum ionic liquid (ammonium 3-butyl-4-methyl-5-vinylthiazolylmolybdate) is controlled at 1.0–3.0, ensuring dispersibility while avoiding excessive cost. Furthermore, its phosphorus-free nature improves the environmental friendliness of the grease.

[0023] Preferably, the first base oil comprises paraffinic mineral oil and polyalphaolefin (PAO) in a mass ratio of (70-80):(20-30). The paraffinic mineral oil has a kinematic viscosity of 100-120 cSt at 40°C, and the PAO has a kinematic viscosity of 20-100 cSt at 40°C. This mixed base oil exhibits good fluidity, viscosity stability, and high / low temperature adaptability, providing a stable dispersion carrier for molybdenum-based composite additives while improving the low-temperature fluidity and high-temperature oxidation resistance of the grease.

[0024] Preferably, the thickener is a lithium composite soap with a saponification degree of 92%–96%. Lithium composite soap possesses excellent thickening ability, high-temperature stability, and water erosion resistance. It can effectively encapsulate the base oil and molybdenum-based composite additives, forming a stable grease structure and preventing additive sedimentation. Simultaneously, it exhibits good compatibility with sealing sleeve materials (polychloroprene rubber, thermoplastic elastomers), preventing sealing sleeve degradation and failure.

[0025] Preferably, the lithium complex soap is prepared by saponification of a second base oil, 12-hydroxystearic acid, sebacic acid, and lithium hydroxide. The second base oil may be the same as or different from the first base oil.

[0026] Preferably, the preparation method of the lithium composite soap includes the following steps: 12-hydroxystearic acid and sebacic acid are mixed in a weight ratio of (7-10):(1-5) and added to a reaction device, then a second base oil is added, the weight of which is 3-5 times the total weight of 12-hydroxystearic acid and sebacic acid, the temperature is raised to 85-95°C and stirred until completely dissolved; then a lithium hydroxide aqueous solution with a concentration of 8.0-15.0% is slowly added, the temperature is raised to 110-130°C, and the saponification reaction is maintained for 60-90 minutes, with continuous stirring during the saponification reaction, to obtain a lithium composite soap thickener.

[0027] Preferably, the preparation method of the molybdenum dialkyldithiocarbamate includes the following steps: mixing and stirring a hexavalent molybdenum source, a dialkyl secondary amine, and pure water, adding carbon disulfide dropwise, and reacting the mixture at 65-95°C for 5-7 hours; adding a solvent and extracting at 20-60°C for 2-8 hours, separating the upper oil phase, and obtaining the molybdenum dialkyldithiocarbamate by filtration and reduced evaporation.

[0028] Preferably, the hexavalent molybdenum source includes at least one of molybdenum trioxide, sodium molybdate, and ammonium molybdate; the dialkyl secondary amine includes at least one of dipentylamine, diisooctylamine, and 2-n-octyl-1-dodecylamine. The solvent may be gasoline.

[0029] In one specific embodiment, the preparation method of molybdenum dialkyldithiocarbamate includes the following steps: mixing and stirring a hexavalent molybdenum source (such as molybdenum trioxide, sodium molybdate, ammonium molybdate, etc., 5.0-20.0 g), a dialkyl secondary amine (such as dipentylamine, diisooctylamine, 2-n-octyl-1-dodecylamine, etc., 20.0-60.0 g), and pure water (20-50.0 mL), adding carbon disulfide (10-30.0 g) dropwise, and reacting the mixture at 65-95°C for 5-7 h; adding solvent gasoline (50-70 g) and extracting at 20-60°C for 2-8 hours, separating the upper oil phase, filtering and reducing evaporation to obtain molybdenum dialkyldithiocarbamate (MoDTC).

[0030] Preferably, the particle size of the nano-molybdenum disulfide is 50–200 nm.

[0031] A second aspect of the present invention provides a multi-component synergistic modified grease, comprising the following steps: S1. Add nano-molybdenum disulfide, molybdenum dialkyldithiocarbamate and ammonium 3-butyl-4-methyl-5-vinylthiazolylmolybdate to a high-speed mixer, control the speed at 1500-3000 r / min, mix at room temperature for 30-60 min, and obtain a uniformly dispersed molybdenum-based composite additive precursor. S2. Add the thickener to the first base oil, control the temperature at 140-160℃, stir at 800-1200 r / min, and keep stirring at this temperature for 30-60 minutes to fully integrate and form a uniform grease base system; this can further improve the structural stability of the grease and prevent stratification when adding additives later. S3. Slowly add the molybdenum-based composite additive precursor into the grease base system, control the temperature at 110-130℃, the stirring speed at 1200-1500 r / min, and keep it at this temperature for 30-60 min to ensure thorough dispersion; S4. Grind the obtained mixture to remove impurities and agglomerated particles; allow the ground mixture to cool naturally to room temperature and stand for 24 hours. After passing the test, the multi-component synergistic modified grease as described above is obtained.

[0032] In the above preparation method, the precursor is prepared by premixing three molybdenum-based additives to avoid the agglomeration of nano-MoS2 and ensure uniform dispersion of the additives. The subsequent stepwise addition of additives can prevent the additives from decomposing and failing at high temperatures, thereby improving the stability of the grease performance. The grinding process further removes impurities and agglomerated particles, which can optimize the microstructure of the grease and further improve its superlubricating properties.

[0033] The present invention will be further illustrated by the following examples and comparative examples.

[0034] Example 1 A multi-component synergistic modified grease, by weight, is prepared from the following raw materials: 20 parts of a first base oil; 75 parts of a thickener; and 5 parts of a molybdenum-based composite additive precursor. The first base oil is composed of paraffinic mineral oil 100# and PAO8 in a mass ratio of 70:30. Its preparation method includes the following steps: S1. Preparation of molybdenum dialkyldithiocarbamate: 10.2 g sodium molybdate, 25.6 g dipentylamine, and 37.4 g water were added sequentially to a round-bottom flask and stirred until homogeneous. Then, 18.3 g carbon disulfide was added dropwise at 20 °C. After the addition was complete, the temperature was raised to 75 °C and the reaction was carried out for 6 hours. After the reaction was completed, 55 g of 150# solvent oil was added, and the mixture was extracted at 25 °C for 2.5 hours. The upper oil phase was separated, and the oil phase was distilled off under reduced pressure to remove gasoline, yielding a brownish-brown liquid molybdenum dialkyldithiocarbamate (MoDTC-1) product with a yield of 99.0% and a purity of 97.0%. S2. Weigh nano-MoS2 (particle size 100nm), MoDTC-1 and 3-butyl-4-methyl-5-vinylthiazolylmolybdate ammonium salt in a weight ratio of 3.5:4.0:2.5, add them to a high-speed mixer, mix at 1800 r / min at room temperature for 35 min to obtain a molybdenum-based composite additive precursor. S3. Paraffin-based mineral oil 100# and PAO8 oil are compounded at a weight ratio of 70:30 to obtain a second base oil; 12-hydroxystearic acid and sebacic acid are mixed at a weight ratio of 8:2 and added to a reaction vessel. Four times the weight of the second base oil is added, the temperature is raised to 85°C and stirred to dissolve, and 10% lithium hydroxide aqueous solution is slowly added. The temperature is raised to 125°C and kept at the temperature for saponification for 75 minutes to obtain a lithium composite soap thickener system. S4. Add 75 parts of thickener to 20 parts of the first base oil, and stir at 155℃ and 900r / min for 35 minutes to form a grease base system; S5. Add 5 parts of molybdenum-based composite additive precursor, keep warm and stir at 125℃ and 1300r / min for 50min; send to a three-roll mill, grind 3 times, cool to room temperature, stand for 24h, and obtain the finished product after passing the test.

[0035] Example 2 A multi-component synergistic modified grease, by weight, is prepared from the following raw materials: 37 parts of a first base oil; 60 parts of a thickener; and 3 parts of a molybdenum-based composite additive precursor. The first base oil is composed of paraffinic mineral oil 120# and PAO6 in a mass ratio of 75:25. Its preparation method includes the following steps: S1. Preparation of molybdenum dialkyldithiocarbamate: 9.5g of ammonium molybdate, 25.6g of diisooctylamine, and 37.4g of water were added sequentially to a round-bottom flask and stirred until homogeneous. Then, 18.3g of carbon disulfide was added dropwise at 20℃. After the addition was complete, the temperature was raised to 75℃ and the reaction was carried out for 6 hours. After the reaction was completed, 55g of 180# solvent oil was added, and the mixture was extracted at 40℃ for 4 hours. The upper oil phase was separated, and the oil phase was distilled off under reduced pressure to remove gasoline, yielding a brownish-red liquid molybdenum dialkyldithiocarbamate (MoDTC-2) product with a yield of 98.0% and a purity of 98.0%. S2. Weigh nano-MoS2 (particle size 100nm), MoDTC-2 and 3-butyl-4-methyl-5-vinylthiazolylmolybdate ammonium salt in a weight ratio of 4.5:3.0:2.0, add them to a high-speed mixer, mix at 2200 r / min at room temperature for 40 min to obtain a molybdenum-based composite additive precursor. S3. Paraffin-based mineral oil 120# and PAO6 oil were compounded at a weight ratio of 75:25 to obtain a second base oil; 12-hydroxystearic acid and sebacic acid were mixed at a weight ratio of 7:3 and added to a reaction vessel. 3.5 times the weight of the second base oil was added, the mixture was heated to 90°C and stirred to dissolve, and 12% lithium hydroxide aqueous solution was slowly added. The mixture was heated to 115°C and kept at this temperature for saponification for 60 minutes to obtain a lithium composite soap thickener system. S4. Add 60 parts of thickener to 37 parts of the first base oil, keep warm and stir at 150℃ and 1000r / min for 45 minutes to form a grease base system; S5. Add 3 parts of molybdenum-based composite additive precursor, keep warm and stir at 115℃ and 1200r / min for 40min; send to a three-roll mill, grind 3 times, cool to room temperature, stand for 24h, and obtain the finished product after passing the test.

[0036] Example 3 A multi-component synergistic modified grease, by weight, is prepared from the following raw materials: 68 parts of a first base oil; 25 parts of a thickener; and 7 parts of a molybdenum-based composite additive precursor. The first base oil is composed of paraffinic mineral oil 120# and PAO10 in a mass ratio of 80:20. Its preparation method includes the following steps: S1. Add 10.2g sodium molybdate, 25.6g 2-n-octyl-1-dodecylamine, and 37.4g water to a round-bottom flask in sequence, stir well, and then add 18.3g carbon disulfide dropwise at 20℃. After the addition is complete, raise the temperature to 75℃ and react for 6 hours. After the reaction is complete, add 55g 200# solvent oil, extract at 50℃ for 6 hours and separate the upper oil phase. Distill the oil phase under reduced pressure to remove gasoline, and obtain a brownish-brown liquid molybdenum dialkyldithiocarbamate (MoDTC-3) product with a yield of 98.5% and a purity of 98.5%. S2. Weigh nano-MoS2 (particle size 100nm), MoDTC-3 and 3-butyl-4-methyl-5-vinylthiazolylmolybdate ammonium salt in a weight ratio of 3.5:5.0:1.5, add them to a high-speed mixer, mix at 2500 r / min at room temperature for 50 min to obtain a molybdenum-based composite additive precursor. S3. Paraffin-based mineral oil 120# and PAO10 oil are compounded at a weight ratio of 80:20 to obtain a second base oil; 12-hydroxystearic acid and sebacic acid are mixed at a weight ratio of 9:1 and added to a reaction vessel. 4.9 times the weight of the second base oil is added, the mixture is heated to 90°C and stirred to dissolve, and 10% lithium hydroxide aqueous solution is slowly added. The mixture is heated to 128°C and kept at this temperature for saponification for 80 minutes to obtain a lithium composite soap thickener system. S4. Add 25 parts of thickener to 68 parts of the first base oil, and stir at 158°C and 1200r / min for 55 minutes to form a grease base system; S5. Add 7 parts of molybdenum-based composite additive precursor, keep warm and stir at 127℃ and 1400r / min for 50min; send to a three-roll mill, grind 3 times, cool to room temperature, stand for 24h, and obtain the finished product after passing the test.

[0037] Example 4 A multi-component synergistic modified grease, which differs from Example 1 in that it uses MoDTC-2 instead of MoDTC-1.

[0038] Example 5 A multi-component synergistic modified grease, which differs from Example 1 in that it uses MoDTC-3 instead of MoDTC-1.

[0039] Comparative Example 1 A multi-component synergistic modified grease, the preparation method of which differs from that of Example 1, is that only a single nano-MoS2 (particle size 100nm) is used as an additive in S5.

[0040] Comparative Example 2 A multi-component synergistic modified grease, the preparation method of which differs from that of Example 1, is as follows: in S2, nano MoS2 (particle size 100nm) and 3-butyl-4-methyl-5-vinylthiazolylmolybdate ammonium salt are weighed in a weight ratio of 3.5:2.5 to prepare a molybdenum-based composite additive precursor.

[0041] The performance of the above embodiments and comparative examples was tested using the following methods: 1. Copper sheet corrosion test The copper sheet corrosion test was conducted according to the national standard NB / SH / T 0324-2010. The grease sample was completely wrapped around the polished copper sheet, placed in a test tube, and tested at 100℃ in an oven for 24 hours to determine the degree of copper sheet corrosion.

[0042] 2. Wear resistance test The lubricating performance of grease was evaluated using a four-ball friction and wear tester. The test conditions were: 392 N, 1200 r / min, 60 min, and 75 °C. A lower coefficient of friction and a smaller wear scar diameter indicate better lubrication performance of the grease.

[0043] 3. Friction Reduction Performance Test The friction reduction test was conducted on an SRV5 friction and wear testing machine. The test conditions were: load 200N, temperature 100℃, frequency 50Hz, stroke 2mm, test time 120min, and contact method was line contact (ball to disc).

[0044] The MoDTC products from Examples 1, 2, and 3 were tested using inductively coupled plasma optical emission spectrometry (ICP). The lubricating oil was added to PAO8 base oil at a dosage of 1.0 wt.% and stirred at 65°C for 30 minutes to test its friction-reducing properties. The friction-reducing performance was tested on an OPTIMAL SRV5 friction and wear testing machine (Germany). The experimental conditions were: load 200 N, temperature 100°C, frequency 50 Hz, stroke 2 mm, test time 60 min, ball-to-disc contact. The results are shown in Table 1.

[0045] Table 1. Elemental analysis and wear reduction performance of the samples

[0046] As can be seen from the friction and wear data, MoDTC has a high sulfur and molybdenum content, and the addition of 1.0 wt.% MoDTC to PAO8 base oil has a significant friction-reducing effect, which plays an important role in extending the service life of mechanical equipment.

[0047] Examples 1-5 and Comparative Examples 1-2 were subjected to copper sheet corrosion, friction reduction and wear resistance tests. The results are shown in Table 2 below.

[0048] Table 2

[0049] The copper sheet corrosion test results show that all test groups have good corrosion resistance. Because they do not contain phosphorus, they avoid the environmental pollution and corrosion of equipment metal caused by traditional phosphorus-containing additives.

[0050] The data on wear scar diameter and friction coefficient show that the molybdenum-based composite additive in Example 3 has a higher content, the smallest wear scar diameter, and the lowest friction coefficient. All three MODTCs prepared within the formulation process range have significant friction-reducing effects and can effectively improve the friction performance of the grease. Compared with the grease using a single additive (Comparative Example 1), the friction coefficient is reduced by 30.8%, the wear scar diameter is reduced by 31.3%, and the super-lubricating performance is significantly improved, which can effectively reduce equipment friction and wear and reduce energy consumption. Compared with Comparative Example 2, the strong addition of the self-made MODTC can better exert the role of the molybdenum-based composite additive and improve the friction-reducing and anti-wear performance of the grease.

[0051] The test results above show that the greases prepared in Examples 1-5 of this invention are significantly better than those in Comparative Examples 1 and 2 in terms of friction coefficient, wear scar diameter, high temperature adaptability and storage stability. This fully demonstrates the innovation and superiority of the combination and ratio design of molybdenum-based composite additives in the preparation of multi-component synergistic modified greases.

[0052] It is understood that those skilled in the art can make equivalent substitutions or modifications to the technical solution and inventive concept of the present invention, and all such substitutions or modifications should fall within the protection scope of the appended claims.

Claims

1. A multi-component synergistic modified grease, characterized in that, The raw materials for its preparation, by weight, include: a total of 100 parts of thickener, molybdenum-based composite additives and first base oil, wherein the thickener is 25.0 to 75.0 parts and the molybdenum-based composite additives are 2.0 to 8.0 parts; The molybdenum-based composite additives include nano-molybdenum disulfide (MoS2), molybdenum dialkyl dithiocarbamate (MoDTC), and ammonium 3-butyl-4-methyl-5-vinylthiazolyl molybdate.

2. The multi-component synergistic modified grease according to claim 1, characterized in that, The weight ratio of the nano-molybdenum disulfide (MoS2), molybdenum dialkyl dithiocarbamate (MoDTC) and ammonium 3-butyl-4-methyl-5-vinylthiazolyl molybdate is (2.5-4.5):(3.0-5.0):(1.0-3.0).

3. The multi-component synergistic modified grease according to claim 1, characterized in that, The first base oil comprises paraffinic mineral oil and polyalphaolefin in a mass ratio of (70-80):(20-30).

4. The multi-component synergistic modified grease according to claim 1, characterized in that, The thickener is a lithium composite soap with a saponification degree of 92% to 96%.

5. The multi-component synergistic modified grease according to claim 4, characterized in that, The lithium complex soap is prepared by saponification reaction of a second base oil, 12-hydroxystearic acid, sebacic acid and lithium hydroxide.

6. The multi-component synergistic modified grease according to claim 5, characterized in that, The preparation method of the lithium composite soap includes the following steps: 12-hydroxystearic acid and sebacic acid are mixed in a weight ratio of (7-10):(1-5) and added to a reaction apparatus. Then, a second base oil is added, the weight of which is 3-5 times the total weight of 12-hydroxystearic acid and sebacic acid. The mixture is heated to 85-95°C and stirred until completely dissolved. Subsequently, an 8.0-15.0% lithium hydroxide aqueous solution is slowly added, and the mixture is heated to 110-130°C. The saponification reaction is maintained at this temperature for 60-90 minutes, with continuous stirring during the saponification process, to obtain a lithium composite soap thickener.

7. The multi-component synergistic modified grease according to claim 1, characterized in that, The preparation method of the molybdenum dialkyldithiocarbamate includes the following steps: A hexavalent molybdenum source, a dialkyl secondary amine, and pure water were mixed and stirred. Carbon disulfide was added dropwise, and the mixture was reacted at 65–95°C for 5–7 hours. A solvent was added, and the mixture was extracted at 20–60°C for 2–8 hours. The upper oil phase was separated, and the mixture was obtained by filtration and reduced evaporation.

8. The multi-component synergistic modified grease according to claim 7, characterized in that, The hexavalent molybdenum source includes at least one of molybdenum trioxide, sodium molybdate, and ammonium molybdate; the dialkyl secondary amine includes at least one of dipentylamine, diisooctylamine, and 2-n-octyl-1-dodecylamine.

9. The multi-component synergistic modified grease according to claim 1, characterized in that, The particle size of the nano-molybdenum disulfide is 50–200 nm.

10. A multi-component synergistic modified grease, characterized in that, The steps include the following: S1. Nano molybdenum disulfide, molybdenum dialkyldithiocarbamate and ammonium 3-butyl-4-methyl-5-vinylthiazolylmolybdate are mixed to obtain a uniformly dispersed molybdenum-based composite additive precursor. S2. Add the thickener to the first base oil, control the temperature at 140-160℃, stir at 800-1200 r / min, keep stirring at the temperature for 30-60 minutes to fully blend and form a uniform grease base system; S3. Slowly add the molybdenum-based composite additive precursor into the grease base system, control the temperature at 110-130℃, the stirring speed at 1200-1500 r / min, and keep stirring at this temperature for 30-60 min to ensure thorough dispersion; S4. Grind the obtained mixture to remove impurities and agglomerated particles; allow the ground mixture to cool naturally to room temperature to obtain the multi-component synergistic modified grease as described in any one of claims 1-9.

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