Lubricating grease composition with wide temperature range and stable performance as well as preparation method and application of lubricating grease composition

Abstract

The invention relates to the technical field of lubricating materials, and discloses a lubricating grease composition with wide temperature range stable performance as well as a preparation method and application of the lubricating grease composition with wide temperature range stable performance, and the lubricating grease composition with wide temperature range stable performance comprises the following components in parts by weight: 55-65 parts of perfluoropolyether; 10 to 15 parts of polysiloxane; 10 to 15 parts of polyisoolefin; 8 to 12 parts of a multi-block polyurea thickening agent; 2 to 4 parts of fluorine modified nano bentonite; 1 to 2 parts of graphene; 0.5 to 1.5 parts of a carbon nano cage; 0.5 to 1.0 part of nano boron nitride; 1 to 2 parts of a block polyether-silane copolymer; and 0.4-1.6 parts of an antioxidant, a heat stabilizer and an anti-wear agent. Through introduction of a composite thickening network, nano material synergistic enhancement, an interface regulator and magnetic field-thermal stress cycle treatment, the stability, particle dispersity and restorability of the lubricating grease in a wide temperature range are remarkably improved, and long-term efficient lubricating performance is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of lubricating materials, and particularly to a grease composition with stable performance in a wide temperature range, a preparation method thereof, and an application thereof. Background Art

[0002] In working conditions where extreme temperature differences frequently switch or equipment operates continuously for a long time, grease is not only a simple medium for reducing friction, but also a "structural material" for maintaining the stable operation of mechanical systems. Especially in environments such as aerospace, rail transit, and deep-sea engineering, lubricants need to withstand severe thermal shock, high-shear disturbance, and the influence of time aging.

[0003] Current grease technology has made progress in multiple directions. For example, primary structure networks are established using polyurea or metal soap thickeners to form good mechanical stability and basic consistency; some systems introduce nano-oxides or carbon materials to improve anti-wear performance, and a small amount of addition can significantly reduce the friction coefficient. In order to improve the dispersion efficiency, some technologies also use high-shear or heating and stirring treatments, which help to improve the uniformity of particle distribution. These existing solutions can meet the basic lubrication requirements of normal temperature environments and medium-low frequency working systems and have good performance within a certain temperature range.

[0004] However, there are still some deficiencies in these existing technologies. First, the structure of the thickening system is often fragile, and phase separation of the grease is likely to occur under low-temperature conditions, which cannot be solved simply by adjusting the consistency. Second, although the addition of nano-particles can improve the performance, they often form agglomeration nuclei due to unstable dispersion, which instead destroys the original network and weakens the enhanced effect. In addition, existing processes generally rely on static stirring and natural cooling, lacking an orderly guiding step for the micro-structure, resulting in poor recovery of the system after experiencing thermal cycling and weak "memory" of the structure. Especially under repeated high and low temperature alternation, the internal stress accumulation in the system is difficult to self-release, manifested as a decrease in dropping point, a decrease in consistency, lubrication failure, and other phenomena. Summary of the Invention

[0005] Aiming at the deficiencies of the existing technology, the present invention provides a grease composition with stable performance in a wide temperature range, a preparation method thereof, and an application thereof, solving the problems of unstable structure, particle agglomeration, and poor recovery of grease in high and low temperature cycles and long-term use in the existing technology.

[0006] To achieve the above object, the present invention is realized through the following technical solutions: According to the first aspect of the present invention, a grease composition with stable performance in a wide temperature range is provided. The grease composition includes the following components in parts by weight: Perfluoropolyether: 55 - 65 parts. Perfluoropolyether (PFPE) is a base oil with high chemical stability and low volatility. The fluorocarbon chain structure of PFPE endows it with excellent antioxidant and chemical inertness, especially showing excellent stability under extremely high temperature (above 250 °C) or low temperature (below -60 °C). In a high-temperature environment, the volatility of PFPE is low, avoiding the rapid evaporation of the lubricating oil, thereby increasing the service life of the grease; Polysiloxane: 10 - 15 parts. Polysiloxane (PSO) has high molecular flexibility and adhesiveness, making it play a good regulating role in the grease. Polysiloxane enhances the fluidity and low-temperature performance of the grease through the flexible action of the molecular chain, improves the viscosity performance of the grease under low-temperature conditions, and has lipophilicity, which can form a stable lubricating film on the lubricating surface, helping to reduce friction and wear; Polyisobutene (PIO): 10 - 15 parts. Polyisobutene, as one of the base oils of lubricating oil, has excellent antioxidant, corrosion resistance and good lubricity. The molecular structure of PIO can form a uniform lubricating layer on the friction surface, reduce the friction coefficient, and effectively reduce wear; Multi-block polyurea thickener: 8 - 12 parts. The physical cross-linking structure formed by different polymerization segments in the multi-block polyurea molecule enables the grease to maintain a stable consistency at high and low temperatures. This thickener can respond to temperature changes, having a low viscosity at high temperatures and being able to restore its original structure at low temperatures, improving the working performance of the grease under different temperature conditions; Fluorine-modified nano-bentonite: 2 - 4 parts. Fluorine-modified nano-bentonite enhances the thermal stability and anti-shear performance of the grease through its nano-structure. The layered structure of nano-bentonite forms a network structure in the grease, which can increase the anti-shear force and the stability of the structure of the grease, preventing the grease from thinning or failing under high temperature or high-speed friction; Graphene: 1 - 2 parts. The two-dimensional structure of graphene endows it with extremely high thermal conductivity, helping the grease to dissipate heat at high temperatures and avoiding the degradation of the grease caused by overheating; Carbon nanocage: 0.5 - 1.5 parts. Carbon nanocage has an extremely high specific surface area and mechanical strength, which can enhance the structural stability of the grease, especially showing strong anti-shear force under extreme pressure and temperature conditions. Due to its spherical structure, carbon nanocage can self-repair during the friction process, slow down the aging process of the grease, and improve its long-term use stability; Nano boron nitride: 0.5 - 1.0 parts. Nano boron nitride has good high-temperature resistance and can effectively maintain the structural stability of the grease in a high-temperature environment. Nano boron nitride can provide an additional sliding surface through its planar structure, effectively reducing friction and wear and improving lubrication performance. Block polyether-silane copolymer: 1 - 2 parts. The block polyether-silane copolymer is an interface regulator that can improve the rheology and structural stability of the grease at different temperatures. The structure of the block polyether-silane copolymer is formed by connecting polyether diol and organosilane through an esterification reaction. In the molecular structure, there is an alternating segment structure between the polyether segment and the silane segment. Preferably, the grease composition further comprises: 2,6-Di-tert-butyl-p-cresol: 0.1 - 0.5 parts. 2,6-Di-tert-butyl-p-cresol reacts with free radicals through the phenolic hydroxyl group in its molecule, inhibiting the occurrence of oxidation chain reactions and reducing the concentration of free radicals in the grease. Free radicals are usually formed under high-temperature conditions, which in turn accelerates the oxidation of the grease. By capturing free radicals, BHT effectively prevents the oxidation degradation process of the grease. Phosphite heat stabilizer: 0.2 - 0.6 parts. The action mechanism of the phosphite heat stabilizer is mainly to provide antioxidant effects and reduce the rate of high-temperature thermal decomposition reactions in the oil product. The phosphoric acid ester group in its molecule can react with substances such as free radicals and peroxides at high temperatures, thereby slowing down the thermal degradation of the base oil and thickening agent in the grease. At extreme temperatures, the phosphite can effectively prevent carbonization reactions in the grease, reducing the formation of unstable polymers and gums and maintaining the structure and fluidity of the grease. Zinc dialkyldithiophosphate: 0.1 - 0.5 parts. Zinc dialkyldithiophosphate (ZDDP) is an anti-wear agent that can form a protective film on the friction surface, reducing friction and effectively improving anti-wear performance. When friction occurs on the metal surface, ZDDP molecules will decompose, releasing sulfur-containing groups that adsorb on the friction surface, reducing direct metal contact, thereby reducing friction and wear. The formation of this film can significantly reduce the friction coefficient and improve the durability of the friction components. The sulfur element in ZDDP can effectively react with the metal surface to form an anti-corrosion film layer, preventing the generation of corrosive substances due to metal surface reactions in the grease at high temperatures.

[0007] According to the second aspect of the present invention, there is provided a method for preparing a grease composition with wide-temperature-range stability performance for preparing the above-mentioned grease composition with wide-temperature-range stability performance, comprising the following steps: S1. Blending of base oils; S2. Addition and dispersion of the main thickening agent and the auxiliary thickening agent; S3. Dispersion and introduction of the nanostructure enhancer; S4. Mixing of the interface regulator; S5. Field-assisted structure induction treatment; S6. Vacuum degassing treatment: Perform vacuum degassing treatment to obtain grease; S7. Thermal stress cycle training, place the grease in a thermal cycling device for heat and cold alternating treatment; the temperature in the low-temperature zone is -40 to -60 °C, and the temperature in the high-temperature zone is 180 - 220 °C; cycle 3 - 5 times, and the heat preservation time for each round is 2 - 4 hours. Through thermal stress cycling, the thickener and structure enhancer of the grease are tested through multiple rounds of temperature changes to ensure that it can maintain excellent lubricating performance under both low-temperature and high-temperature conditions. At low temperatures, the thickener can provide sufficient structural stability, while at high temperatures, the grease needs to be able to return to a lower viscosity; S8. Cooling and encapsulation: Cool the grease mixture to room temperature (20 - 25 °C); during the cooling process, control the stirring rate at 50 - 150 rpm to prevent the formation of bubbles and layering; after cooling is completed, fill the grease into a sealed container. Finally, perform a standing treatment, and control the standing time to be ≥7 days. Slow cooling and proper stirring help the grease avoid large-particle precipitation and layering during the cooling process. By controlling the stirring rate, the various components of the grease can be evenly distributed, avoiding performance instability caused by uneven cooling. After the standing treatment, the components of the grease can be fully fused, and the interaction of the components reaches the best state, thereby further improving the stability and performance of the grease. The standing process helps to eliminate possible tiny bubbles and improve the overall quality of the final product.

[0008] Preferably, the compounding of the base oil includes: Stir and mix perfluoropolyether, polysiloxane, and polyisobutene at 50 - 70 °C. The mixing of perfluoropolyether, polysiloxane, and polyisobutene depends on their compatibility. Perfluoropolyether has high chemical stability and extremely low volatility, polysiloxane provides good low-temperature performance, while polyisobutene has good antioxidant and lubricating properties at high temperatures. By heating and proper stirring, the base oil molecules with different properties can be better fused to form a stable base oil system; control the stirring rate at 100 - 300 rpm and the time at 20 - 40 min to form a uniform base oil system. By controlling the mixing within the temperature range of 50 - 70 °C, the rheological properties of the base oil can be effectively adjusted. The fluidity and viscosity of the base oil are most appropriate at this temperature, enabling the base oil molecules to better diffuse and dissolve with each other without being too viscous or generating too much heat.

[0009] Preferably, the addition and dispersion of the main thickener and auxiliary thickener include: Add multi-block polyurea and fluorine-modified nano-bentonite to the base oil. In this step, the segments of the multi-block polyurea molecular chains start to form a preliminary network structure in the base oil through intermolecular physical cross-linking, thereby providing the consistency and adhesiveness of the grease. The addition of such thickeners enables the grease to maintain a relatively low viscosity at high temperatures while providing a high consistency at low temperatures to meet the requirements of different working conditions. The fluorine-modified bentonite enhances its affinity with the base oil through its surface modification, ensuring its stable dispersion in the grease. Nano-bentonite can form close contact with the base oil through its large specific surface area and layered structure, thereby enhancing the shear resistance and thermal stability of the grease; Stir at a high speed under the conditions of 70-90 °C, with a rotation speed of 600-1000 rpm. Under the temperature conditions in the range of 70-90 °C, the molecular activity of the thickener is enhanced, which is conducive to its interaction with the molecules in the base oil and promotes the formation of the thickening network structure; High-speed stirring (600-1000 rpm) can effectively evenly distribute the multi-block polyurea and fluorine-modified nano-bentonite throughout the grease, ensuring that the dispersion of the thickener does not show precipitation, caking or unevenness; The stirring time is 30-60 min to form a primary thickening network structure. The stirring time in this range can achieve sufficient mixing and dispersion to prevent uneven stirring caused by too little stirring time.

[0010] Preferably, the dispersion and introduction of the nanostructure enhancer include: Disperse graphene, carbon nanocages and nano-boron nitride in a part of the base oil to obtain a dispersion; Use ultrasonic treatment or high-shear emulsification method for dispersion treatment, and the treatment time is 10-20 min. The cavitation effect caused by ultrasonic waves generates extremely strong shear force, which can effectively disperse the nanoparticles. The tiny bubbles formed in the liquid will rapidly expand and collapse, releasing powerful energy to break the intermolecular forces (such as van der Waals forces and electrostatic forces) between the nanoparticles, thereby achieving uniform dispersion of the nanoparticles. The high-shear emulsification method generates strong shear force through a high-speed rotating stirrer to disperse the nanoparticles into extremely fine particles and can overcome the cohesion between the particles, making them evenly distributed in the grease. This method is particularly suitable for nanoparticles with larger particle sizes and can ensure their stability in the grease; Slowly add the dispersion to the mixing system and continue stirring for 15-30 min. After dispersion treatment, slowly adding the dispersion to the mixing system helps to avoid re-aggregation of particles caused by suddenly adding too much dispersion. Slowly adding ensures that various nano-materials can be more evenly distributed throughout the system, reduces the problem of excessive local concentration, and ensures the stability and performance consistency of the grease.

[0011] Preferably, the mixing of the interface regulator includes: A block polyether-silane copolymer is added to the above system. This copolymer can form an effective interface between the oil phase and the solid phase of the grease, thereby improving the rheology, stability and lubrication effect of the grease; The stirring temperature is maintained at 60 - 80 °C. Under the stirring condition of 60 - 80 °C, the block polyether-silane copolymer can effectively interact with other grease components at the molecular level, prevent the stratification or agglomeration of the grease components, and ensure the stability and uniformity of the grease. By adjusting the stirring rate and temperature, sufficient mixing of the interface regulator and other components can be achieved in a relatively short time, avoiding performance fluctuations caused by uneven distribution; The stirring rate is 400 - 800 rpm, and the stirring time is 10 - 20 min. The stirring rate is controlled at 400 - 800 rpm, and the stirring time is 10 - 20 minutes. This process aims to ensure that the block polyether-silane copolymer can be fully dispersed to form a uniform molecular layer, ensuring the stability among the components in the grease.

[0012] Preferably, the field-assisted structure induction treatment includes: The mixture is placed in a magnetic field induction system for treatment. As a two-dimensional material with an extremely high specific surface area, graphene has very strong electrical conductivity, thermal conductivity and mechanical strength. Under the action of the magnetic field, the graphene sheets will produce a spin effect and form an oriented arrangement. This arrangement not only improves the anti-wear and anti-friction properties of graphene, but also improves the thermal conductivity of the grease, preventing the grease from overheating in a high-temperature environment; The magnetic field strength is 400 - 800 Gauss. Graphene and other nanomaterials have weak magnetism or can regulate their molecular directions through an external magnetic field. The magnetic field strength in the range of 400 - 800 Gauss is sufficient to promote their arrangement and effectively improve their dispersibility in the grease. Through this technology, the oriented arrangement of graphene helps to form a more stable lubricating film between the friction surfaces, reducing wear and improving lubrication efficiency; The treatment time is 10 - 20 min, which is used to induce the oriented arrangement of graphene and nanomaterials. The treatment time of 10 - 20 minutes is to ensure that the magnetic field has a sufficient impact on the oriented arrangement and distribution of the nanomaterials. Too short a time may not effectively induce the arrangement of the nanomaterials, while too long a time may cause damage to the material structure or excessive arrangement, thus affecting the overall performance of the grease. Therefore, an appropriate treatment time can ensure that the grease has the best performance in the final product.

[0013] Preferably, the vacuum degassing treatment includes: Vacuum degassing is carried out at 60 - 80 °C to obtain grease; the vacuum degree is set at -0.08 to -0.1 MPa; the degassing time is 20 - 40 min. In a vacuum environment, the gas solubility in the liquid decreases, and the gas escapes from the grease system. By heating the grease to 60 - 80 °C, the molecular motion intensifies, which helps the gas to escape. The increase in temperature enables the dissolved gas to be released more rapidly, thereby improving the degassing efficiency. The vacuum environment provides a low-pressure state, further reducing the gas solubility and promoting the release of gas. Conducting degassing treatment within the range of 60 - 80 °C can effectively remove the dissolved gas while ensuring that the temperature of the grease does not become too high, preventing the degradation of sensitive components in the grease, such as polymers or other active molecules, due to excessive temperature; the degassing time is 20 - 40 minutes, and this time length can ensure the complete removal of gas and volatile substances without causing unnecessary changes in the molecular structure of the grease due to over-degassing.

[0014] According to the third aspect of the present invention, there is provided an application of the above grease composition with wide-temperature-range stability performance or a grease composition with wide-temperature-range stability performance obtained by the above preparation method in aerospace equipment.

[0015] The present invention provides a grease composition with wide-temperature-range stability performance, its preparation method and application. It has the following Beneficial effects: 1. The present invention adopts a composite thickening system of multi-block polyurea and fluorine-modified nano-bentonite, achieving the technical effect of maintaining stable consistency and uniform structure under high shear and long-term static conditions. Compared with the prior art technical solutions that only use a single metal soap or polyurea thickener, it solves the deficiencies of easy oil separation and loose network structure in thermal stress or low-temperature environments.

[0016] 2. The present invention realizes the mechanical retention and lubrication performance stability of the grease in a wide temperature range by introducing a synergistic reinforcement system of graphene, carbon nanocages and nano-boron nitride. Compared with the traditional scheme of adding a single inorganic nano-particle, it solves problems such as large thermal expansion mismatch and poor structure orientation, enabling the grease to have good thermal conductivity and structural rigidity.

[0017] 3. The present invention further introduces a block polyether-silane copolymer as an interface regulator, significantly improving the dispersion stability and network coating efficiency of nano-materials in the base oil system. Compared with the existing schemes that do not use an interface modifier or only rely on the polarity adjustment of the base oil, it effectively solves the problems of nano-particle aggregation, local desorption and micro-phase separation, enhancing the overall system consistency and anti-stratification ability.

[0018] 4. The present invention adopts a composite treatment path of magnetic field-assisted structure induction and thermal stress cycle training to achieve the directional arrangement of the microstructure of the grease and the improvement of the stress self-adaptability of the macroscopic structure. Compared with the existing solutions that rely on physical stirring or static molding, it solves the deficiencies of weak structural memory and lagging temperature change response, enabling the material to maintain stable performance output under extreme thermal cycle conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a flowchart of the preparation method of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the specification of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0021] Please refer to the attached Figure 1 : Example 1: Formulation (unit: parts by weight): Perfluoropolyether: 60 parts; Polysiloxane: 12 parts; Polyisobutene: 12 parts; Multi-block polyurea thickener: 10 parts; Fluorine-modified nano-bentonite: 3 parts; Graphene: 1.5 parts; Carbon nanocage: 1 part; Nanoboron nitride: 0.8 part; Block polyether-silane copolymer: 1.5 parts; Di-tert-butyl-p-cresol: 0.3 part; Phosphite thermal stabilizer: 0.4 part; Zinc dialkyldithiophosphate: 0.3 part.

[0022] Preparation process: 1. Blending of base oils: Perfluoropolyether, polysiloxane, and polyisobutene are stirred and mixed at 60 °C with a stirring rate of 200 rpm for 30 minutes to form a uniform base oil system.

[0023] 2. Addition and dispersion of the main thickener and auxiliary thickener: Add multi-block polyurea and fluorine-modified nano-bentonite to the base oil, and carry out high-speed stirring at 80 °C. The stirring rate is 800 rpm and the stirring time is 40 minutes to form a primary thickening network structure.

[0024] 3. Dispersion and introduction of nano-structural enhancer: Disperse graphene, carbon nanocages and nano-boron nitride in part of the base oil, and carry out ultrasonic treatment for 15 minutes.

[0025] Slowly add the dispersion into the mixed system and continue stirring for 25 minutes.

[0026] 4. Mixing of interfacial regulator: Add block polyether-silane copolymer to the system, and carry out stirring at 70 °C. The stirring rate is 600 rpm and the stirring time is 15 minutes.

[0027] 5. Field-assisted structure induction treatment: Place the mixture in a magnetic field induction system for treatment. The magnetic field strength is 600 Gauss and the treatment time is 15 minutes to induce the directional arrangement of graphene and nano-materials.

[0028] 6. Vacuum degassing treatment: Carry out vacuum degassing at 70 °C. The vacuum degree is set at -0.09 MPa and the degassing time is 30 minutes.

[0029] 7. Thermal stress cycle training: Place the grease in a thermal cycling device for cold and hot alternating treatment. The temperature in the low-temperature zone is -50 °C, the temperature in the high-temperature zone is 200 °C, cycle 4 times, and the heat preservation time for each cycle is 3 hours.

[0030] 8. Cooling and encapsulation: Cool the grease mixture to 25 °C. During the cooling process, control the stirring rate at 100 rpm to prevent the formation of bubbles and stratification. After cooling, fill it into a sealed container and carry out static treatment for 7 days.

[0031] Example 2: Formulation (unit: parts by weight): Perfluoropolyether: 62 parts; Polysiloxane: 11 parts; Polyisobutene: 11 parts; Multi-block polyurea thickener: 9 parts; Fluorine-modified nano-bentonite: 3.5 parts; Graphene: 1 part; Carbon nanocage: 1.2 parts; Nano-boron nitride: 0.6 part; Block polyether-silane copolymer: 1.8 parts; 2,6-Di-tert-butyl-p-cresol: 0.2 parts; Phosphite heat stabilizer: 0.3 parts; Zinc dialkyldithiophosphate: 0.3 parts.

[0032] Preparation process: 1. Blending of base oils: Perfluoropolyether, polysiloxane, and polyisobutene are mixed at 65 °C with a stirring rate of 250 rpm for 25 minutes.

[0033] 2. Addition and dispersion of main thickener and auxiliary thickener: Multiblock polyurea and fluorine-modified nanobentonite are added to the base oil and stirred at high speed at 85 °C with a stirring rate of 900 rpm for 50 minutes to form a primary thickening network structure.

[0034] 3. Dispersion and introduction of nanostructure enhancer: Graphene, carbon nanocages, and nano boron nitride are dispersed in a portion of the base oil using high-shear emulsification for 12 minutes.

[0035] The dispersion is slowly added to the mixed system and stirring is continued for 20 minutes.

[0036] 4. Blending of interfacial regulator: Block polyether-silane copolymer is added at 75 °C with a stirring rate of 500 rpm for 18 minutes.

[0037] 5. Field-assisted structure induction treatment: The mixture is placed in a magnetic field induction system for treatment with a magnetic field strength of 600 Gauss for 15 minutes.

[0038] 6. Vacuum degassing treatment: Vacuum degassing is carried out at 75 °C with a vacuum degree set at -0.08 MPa for 25 minutes.

[0039] 7. Thermal stress cycle training: Thermal cycling treatment is performed with a low temperature zone of -45 °C and a high temperature zone of 190 °C for 5 cycles, and the holding time for each cycle is 2.5 hours.

[0040] 8. Cooling and encapsulation: The grease is cooled to 20 °C with a stirring rate controlled at 120 rpm for 4 hours and a standing time of 7 days.

[0041] Example 3: Formulation (unit: parts by weight): Perfluoropolyether: 63 parts; Polysiloxane: 13 parts; Polyisoprene: 12 parts; Multiblock polyurea thickener: 10 parts; Fluorine-modified nanobentonite: 3 parts; Graphene: 1.2 parts; Carbon nanocage: 1 part; Nanoboron nitride: 0.9 part; Block polyether-silane copolymer: 1.2 parts; 2,6-Di-tert-butyl-p-cresol: 0.4 part; Phosphite heat stabilizer: 0.3 part; Zinc dialkyldithiophosphate: 0.2 part.

[0042] Preparation process: 1. Blending of base oils: Perfluoropolyether, polysiloxane, and polyisoprene are mixed at 70 °C with a stirring rate of 300 rpm for 35 minutes.

[0043] 2. Addition and dispersion of main thickener and auxiliary thickener: Multiblock polyurea and fluorine-modified nanobentonite are added to the base oil and stirred at high speed at 75 °C with a stirring rate of 700 rpm for 45 minutes to form a primary thickening network structure.

[0044] 3. Dispersion and introduction of nanostructure reinforcing agents: Graphene, carbon nanocage, and nanoboron nitride are dispersed in part of the base oil using ultrasonic treatment for 18 minutes. Then they are slowly added to the mixing system and stirred for 30 minutes.

[0045] 4. Blending of interfacial regulators: Block polyether-silane copolymer is added and stirred at 70 °C with a stirring rate of 600 rpm for 15 minutes.

[0046] 5. Field-assisted structure induction treatment: The mixture is subjected to magnetic field induction treatment with a magnetic field strength of 800 Gauss for 20 minutes.

[0047] 6. Vacuum degassing treatment: Vacuum degassing is carried out at 80 °C with a vacuum degree set at -0.1 MPa for 40 minutes.

[0048] 7. Thermal stress cycle training: The grease is subjected to alternating hot and cold treatment with a low-temperature zone temperature of -55 °C and a high-temperature zone temperature of 210 °C for 3 cycles, and the holding time for each cycle is 4 hours.

[0049] 8. Cooling and Encapsulation: Cool to 22 °C, with a stirring rate of 100 rpm, a cooling time of 6 hours, and a standing time of 7 days.

[0050] Comparative Example 1: Compared with Example 1, the difference is that the block polyether-silane copolymer is not used, and the rest are the same.

[0051] Comparative Example 2: Compared with Example 1, the difference is that the magnetic field induction treatment is not carried out, and the rest are the same.

[0052] Comparative Example 3: Compared with Example 2, the difference is that the fluorine-modified nano-bentonite is not used, and the rest are the same.

[0053] Comparative Example 4: Compared with Example 2, the difference is that ultrasonic treatment is not used to disperse graphene, carbon nanocages, and nano-boron nitride, and the rest are the same.

[0054] Comparative Example 5: Compared with Example 3, the difference is that vacuum degassing treatment is not carried out, and the rest are the same.

[0055] Comparative Example 6: Compared with Example 3, the difference is that the multi-block polyurea thickening agent is not added, and the rest are the same.

[0056] Comparative Experiment: Experimental Purpose: This experiment aims to systematically evaluate the comprehensive effects of the key components and structure construction processes of grease on its macroscopic properties and microstructure.

[0057] I. Experimental Materials: Base Oil System: Perfluoropolyether (PFPE), Polydimethylsiloxane (PDMS), Polyalphaolefin (PAO); Thickening Agent: Multi-block Polyurea, Fluorine-modified Nano-bentonite; Nano-structural Reinforcing Agent: Graphene, Carbon Nanocages, Nano-boron Nitride; Interface Regulator: Block Polyether-silane Copolymer; Auxiliary Materials: Antioxidant (BHT), Heat Stabilizer (Phosphite), Anti-wear Agent (ZDDP).

[0058] II. Experimental Procedures and Testing Processes: Sample Preparation: Each sample (Examples 1 - 3, Comparative Examples 1 - 6) is prepared according to the formula and preparation method to ensure the consistency of the process flow, and the only variable is the corresponding comparison factor.

[0059] Test Example 1: Structural Stability and Anti-stratification After the samples are prepared, they are left standing in an environment of 25 °C; Record the stratification, oil separation, and bubble states every 24 hours for 7 days; On the 7th day, samples were taken to measure consistency (cone penetration method) and an optical microscope was used to observe whether there were residual bubbles.

[0060] Test Example 2: Microstructure and Dispersion State SEM / TEM was used for imaging to observe particle distribution; Dynamic light scattering (DLS) was used to measure particle size distribution; The focus was on observing the orderliness and uniformity of the arrangement of nanomaterials.

[0061] Test Example 3: Rheological Property Analysis A rotational rheometer was used, and the shear rate range was set to 0.1–1000 s -1； A flow curve was obtained to analyze the relationship between apparent viscosity and shear rate; The NLGI grade before and after shear and the thixotropic area were measured to evaluate shear stability.

[0062] Test Example 4: Thermal Stress Cycle Adaptability Test The samples were placed in a thermal cycling device (-50°C to 200°C); Three to five rounds of thermal cycling were carried out, with each round maintaining the temperature for 2–4 hours; The changes in consistency, dropping point, and oil separation rate before and after were evaluated, and the structural stability and memory were investigated (experimental results are shown in the table below).

[0063] Summary Table of Grease Performance Comparison Tests From the above table, it can be obtained that: The base oil acts as the continuous phase, providing a dispersion medium for the thickener and nano-components. The multi-block polyurea and nano-bentonite synergistically form a primary spatial network, ensuring that the system has basic shape retention under static and low-shear conditions. Without the auxiliary thickener, the network structure is not dense enough, and the grease is prone to stratification under gravity or thermal disturbance. The interfacial regulator reduces the interfacial tension between the oil phase and the solid phase at the molecular level, making it easier for nanoparticles to be fixed into the framework, effectively preventing particle migration and interfacial desorption. Structure induction (such as magnetic field treatment) not only makes graphene and nano-boron nitride form an ordered orientation, but also enhances the π-π stacking and van der Waals interactions between particles, constructing highly consistent micro-channels, endowing the grease with stable anti-stratification ability.

[0064] At the dispersion level, the particle size uniformity and network compactness highly depend on the treatment method of the nanostructured enhancer. After using ultrasonic or high-shear technology, two-dimensional materials such as graphene are rapidly exfoliated and uniformly dispersed, reducing the formation of aggregation nuclei. Without this treatment, due to the high specific surface area, there will be a strong aggregation tendency between particles, causing network "hollowing" and a sharp drop in shear stability. In addition, the polar segments of the dispersant form non-covalent bonds with the graphene surface, promoting its stable suspension in the mixed system rather than sedimentation or bridging. This dispersed state supports the extensibility of the thickener network and improves the consistency retention rate of the grease at high shear rates.

[0065] Thermal stress cycling is a unique structure training mechanism. Under the alternating stress of -50°C to 200°C, the thickening network of the grease undergoes repeated expansion and contraction, which helps to eliminate residual stress and form a thermal history memory path. This process deepens the non-covalent connections between particles, such as hydrogen bonds, π-π interactions, and electrostatic synergy, making the network skeleton more flexible and resilient. Samples without this training, even with similar initial properties, are difficult to withstand repeated impacts in extreme temperature ranges. On the contrary, the trained grease can maintain the stability of consistency and dropping point even in an environment with rapid high and low temperature conversion.

[0066] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A grease composition with stable performance in a wide temperature range, characterized in that, The grease composition comprises the following components in parts by weight: Perfluoropolyether: 55 - 65 parts; Polysiloxane: 10 - 15 parts; Polyisobutene: 10 - 15 parts; Multiblock polyurea thickener: 8 - 12 parts; Fluorine-modified nanobentonite: 2 - 4 parts; Graphene: 1 - 2 parts; Carbon nanocage: 0.5 - 1.5 parts; Nanoboron nitride: 0.5 - 1.0 part; Block polyether-silane copolymer: 1 - 2 parts.

2. The grease composition with wide temperature range stability performance according to claim 1, characterized in that, The grease composition further comprises: 2,6-Di-tert-butyl-p-cresol: 0.1 - 0.5 part; Phosphite heat stabilizer: 0.2 - 0.6 part; Zinc dialkyldithiophosphate: 0.1 - 0.5 part.

3. A method for preparing a grease composition with stable performance in a wide temperature range, characterized in that, To prepare the grease composition with wide-temperature stability performance as described in claim 1 or 2, the following steps are included: S1. Compound of base oils; S2. Addition and dispersion of main thickener and auxiliary thickener; S3. Dispersion and introduction of nanostructure enhancer; S4. Mixing of interface regulator; S5. Field-assisted structure induction treatment; S6. Vacuum degassing treatment: Perform vacuum degassing treatment to obtain grease; S7. Thermal stress cycle training, place the grease in a thermal cycling device for cold and hot alternating treatment; the temperature in the low-temperature zone is -40 to -60 °C, and the temperature in the high-temperature zone is 180 - 220 °C; cycle 3 - 5 times, and the heat preservation time for each round is 2 - 4 hours; S8. Cooling and encapsulation: Cool the grease mixture to 20 - 25 °C; during the cooling process, control the stirring rate at 50 - 150 rpm to prevent the formation of bubbles and stratification; after the cooling is completed, fill the grease into a sealed container, and finally, perform a static treatment, and control the static time to be ≥7 days.

4. The preparation method of a grease composition with wide-temperature stability according to claim 3, characterized in that, The compound of the base oils includes: Stir and mix perfluoropolyether, polysiloxane, and polyisobutene at 50 - 70 °C; Control the stirring rate at 100 - 300 rpm and the time at 20 - 40 min to form a uniform base oil system.

5. The preparation method of a grease composition with wide-temperature stability according to claim 3, characterized in that, The addition and dispersion of the main thickener and auxiliary thickener include: Add multiblock polyurea and fluorine-modified nanobentonite to the base oil; Stir at high speed at 70 - 90 °C, and the rotation speed is 600 - 1000 rpm; The stirring time is 30 - 60 min to form a primary thickening network structure.

6. The preparation method of a grease composition with wide temperature range stability performance according to claim 3, characterized in that, The dispersion and introduction of the nanostructure enhancer include: Disperse graphene, carbon nanocage, and nanoboron nitride in part of the base oil to obtain a dispersion; Perform dispersion treatment by ultrasonic treatment or high-shear emulsification method, and the treatment time is 10 - 20 min; Slowly add the dispersion into the mixing system and continue stirring for 15 - 30 min.

7. The preparation method of a grease composition with wide temperature range stability performance according to claim 3, characterized in that, The mixing of the interface regulator includes: Add block polyether-silane copolymer to the above system; Maintain the stirring temperature at 60 - 80 °C; The stirring rate is 400 - 800 rpm, and the stirring time is 10 - 20 min.

8. The preparation method of a grease composition with wide temperature range stability performance according to claim 3, characterized in that, The field-assisted structure induction treatment includes: Place the mixture in a magnetic field induction system for treatment; The magnetic field strength is 400 - 800 Gauss; The treatment time is 10 - 20 min, which is used to induce the directional arrangement of graphene and nanomaterials.

9. The preparation method of a grease composition with wide-temperature stability performance according to claim 3, characterized in that The vacuum degassing treatment includes: Vacuum degassing is carried out at 60 - 80 °C to obtain grease; the vacuum degree is set to -0.08 to -0.1 MPa; the degassing time is 20 - 40 min.

10. An application of a grease composition with wide - temperature - range stability performance as described in claim 1 or 2 in aerospace equipment.

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