A lubricating grease and its preparation method and application

Abstract

This application belongs to the technical field of polymer compound compositions, specifically relating to a lubricating grease, its preparation method, and its application. The preparation method includes: melting and mixing base oil, microcrystalline wax, and polyisobutylene to obtain a thickened base oil solution; adding zinc oxide, tricresyl nonyl phosphate, isobutylene sulfide, polytetrafluoroethylene, and other additives to the thickened base oil solution, and reacting it at 120-130°C to obtain the lubricating grease. This application utilizes an in-situ self-repairing system composed of zinc oxide and isobutylene sulfide. During the operation of the friction pair, isobutylene sulfide releases active sulfur under local temperature rise and shearing action, undergoing a tribochemical reaction with the metal surface to generate an in-situ ferrous sulfide protective film; simultaneously, zinc oxide particles, as a solid repair phase, transfer to the wear area during friction, forming a composite protective layer with the ferrous sulfide. Through the synergistic effect of the above chemical film formation and physical transfer, self-repair of micro-scratches and wear defects on the metal surface is achieved, thereby maintaining the continuity of the lubricating film and improving the load-bearing capacity and scratch resistance of the friction pair.

Description

Technical Field

[0001] This application belongs to the technical field of polymer compound compositions, specifically relating to a chain grease with friction-induced in-situ self-healing capability. Background Technology

[0002] As a core component of mechanical transmission, chains continuously endure high-frequency impacts and intense friction under high-speed operating conditions. They require specialized grease to form a continuous and stable boundary oil film to reliably reduce friction, resist wear, prevent rust, and prevent runoff. High-speed motorcycles, racing engines, and industrial high-speed chains can reach speeds exceeding 5000 rpm. During operation, they experience rapid temperature rise due to friction and high centrifugal force. Ordinary chain greases generally suffer from insufficient viscosity at high temperatures, poor adhesion, and are easily shed or washed away, failing to continuously cover the metal meshing interface. This leads to surface scratches, excessive elongation, corrosion failure, and even instantaneous breakage, severely impacting transmission safety and service life.

[0003] To address this, patent application number 201210427354.5 provides a high-performance high-speed chain grease. This formulation uses a blend of hydroisolated mineral oil and synthetic ester oil as the base oil, combined with a microcrystalline wax and polyethylene wax composite thickener, and synergistically incorporates phenolic / aromatic amine antioxidants, sulfur-phosphorus / boron-containing extreme pressure anti-wear agents, sulfonate rust inhibitors, benzotriazole metal passivators, polytetrafluoroethylene / melamine cyanurate solid lubricant, and polyester / polyisobutylene thickeners. This significantly improves the grease's high-temperature stability, oil film strength, and interfacial adhesion. Performance tests show that commercially available ordinary chain grease has a four-ball test wear scar diameter of 0.67 mm, while this patented grease has a four-ball test wear scar diameter as low as 0.36 mm, demonstrating a significant improvement in both anti-wear and extreme pressure carrying capacity. In addition, during the 20,000-kilometer durability test on actual vehicles, the chain's average tensile strength was only 1.8mm, with no obvious wear, rust, or breakage. Its service life and overall protection capabilities far surpass those of traditional products.

[0004] While this patented grease shows significant improvements over conventional commercially available products in terms of high-temperature resistance, water resistance, rust prevention, and extreme pressure anti-wear properties, there is still room for further optimization in practical applications. Under harsh conditions such as ultra-high speeds, heavy loads, and prolonged high temperatures, its lubricating film strength, shear resistance, and long-term stability remain insufficient. The wear scar size has not yet reached the ideal level for high-end transmission lubrication, and it cannot completely prevent wear caused by microscopic metal-to-metal contact. The overall formulation and the synergistic effect of additives still have room for improvement. Summary of the Invention

[0005] The purpose of this application is to provide a grease with better anti-wear performance and smaller wear scar diameter under the same conditions, which is achieved through the following technical solution:

[0006] A method for preparing a lubricating grease includes the following steps:

[0007] S1, base oil, microcrystalline wax and polyisobutylene are melt-mixed to obtain a base oil thickened liquid;

[0008] S2. Add zinc oxide, isobutylene sulfide, solid lubricant, phenolic antioxidant and rust inhibitor to the base oil thickener, and stir at 120~130℃ to obtain grease;

[0009] The total amount of raw materials for preparing the grease is 100 parts by weight, and the amounts of each component are as follows: 35-60 parts base oil, 25-50 parts thickening binder, 5-15 parts extreme pressure anti-wear agent, 0.5-8 parts solid lubricant, 0.5-3 parts phenolic antioxidant, and 1-8 parts rust inhibitor; the thickening binder includes microcrystalline wax and polyisobutylene, and the extreme pressure anti-wear agent includes zinc oxide and sulfide isobutylene.

[0010] Preferably, the polyisobutylene comprises polyisobutylene with a molecular weight of 2×10⁻⁶. 4 ~1×10 5 Low molecular weight polyisobutylene, and those with a molecular weight greater than 1×10 5 The high molecular weight polyisobutylene; the mass ratio of the low molecular weight polyisobutylene to the high molecular weight polyisobutylene is (5~15):(85~95).

[0011] Preferably, the base oil comprises white oil and pentaerythritol tetraethylhexanoate, wherein the mass ratio of white oil to pentaerythritol tetraethylhexanoate is (4~6):(3~5).

[0012] Preferably, the base oil comprises polyalphaolefin.

[0013] Preferably, the mass ratio of the microcrystalline wax to polyisobutylene is (4~6):(3~5).

[0014] Preferably, the extreme pressure anti-wear agent further includes nonyl tricresyl phosphate; the mass ratio of zinc oxide, nonyl tricresyl phosphate, and isobutylene sulfide is (30~40):(20~30):(0.5~2).

[0015] Preferably, step S2 includes: first adding zinc oxide, solid lubricant, and phenolic antioxidant to the base oil thickening solution, stirring to obtain the reaction solution; then adding tricresyl nonyl phosphate, isobutylene sulfide, and rust inhibitor to the reaction solution to obtain the grease.

[0016] Preferably, the solid lubricant is polytetrafluoroethylene, the rust inhibitor is barium dinonylnaphthalenesulfonate, and the phenolic antioxidant is 2,6-di-tert-butyl-p-cresol.

[0017] Preferably, the melting and mixing temperature in step S1 is 150~180℃.

[0018] A lubricating grease prepared by any of the above-described preparation methods.

[0019] The above-mentioned type of grease is used in transmission friction components, reciprocating sliding parts, and meshing motion pairs.

[0020] Compared with the prior art, this application has the following beneficial effects:

[0021] This application utilizes a multi-component synergistic formulation of a base oil compound system, a microcrystalline wax and high and low molecular weight polyisobutylene composite thickening adhesive, a zinc oxide / isobutylene sulfide / tricresol nonyl phosphate extreme pressure anti-wear system, polytetrafluoroethylene solid lubricant, phenolic antioxidant and rust inhibitor to construct a stable, highly adhesive, and efficient film-forming lubrication system, which significantly improves the load-bearing capacity and scratch resistance of friction pairs.

[0022] The core of this application lies in introducing zinc oxide and isobutylene sulfide as self-healing functional components into the grease system. Unlike traditional greases that rely solely on physical adsorption of the oil film, this application utilizes the localized temperature rise and shearing action generated during friction to activate the extreme pressure activity of isobutylene sulfide, prompting it to undergo a tribochemical reaction with the metal friction pair surface, generating an in-situ protective film primarily composed of ferrous sulfide. Simultaneously, zinc oxide particles in the formulation, acting as a solid repair phase, are transferred to the wear area during friction, forming a composite protective film with ferrous sulfide. Through this synergistic mechanism of "chemical film formation—physical transfer," self-repair of micro-scratches and wear defects on the metal surface is achieved, effectively blocking direct contact between metals and maintaining the continuity of the lubricating film. Furthermore, this application uses polyisobutylene with a specific molecular weight distribution and microcrystalline wax to construct a viscoelastic framework, which not only provides excellent adhesion and anti-detachment properties, but more importantly, this framework can firmly lock active repair agents such as zinc oxide into the micro-gap between the chain pin and the roller, ensuring continuous repair of the friction interface and maintaining the long-term effectiveness of the self-healing effect. Thanks to the aforementioned self-healing mechanism, the wear scar diameter in Example 1 of this application is only 0.255 mm, which is approximately 32.0% lower than that of the commercially available product NIGRIDER TN101L (0.375 mm) and approximately 29.2% lower than the optimal wear scar diameter of the grease in the cited patent (0.36 mm). The friction-reducing and anti-wear effects are significantly better than conventional products, achieving unexpected technical results. Although Examples 2 and 3 did not contain tricresyl nonyl phosphate, their wear scar diameters were 0.397 mm and 0.339 mm, respectively, still comparable to that of the commercially available Comparative Example 1 (0.375 mm). Example 3 exhibits superior anti-wear performance compared to Comparative Example 1 and the cited patent product, while maintaining excellent extreme pressure anti-wear levels overall. Meanwhile, the average friction coefficient of Example 1 remained stable in the range of 0.03 to 0.04, which was more than 50% lower than that of Comparative Example 1 (0.07 to 0.085). The average friction coefficient of Example 2 was 0.055 to 0.065, and the average friction coefficient of Example 3 was 0.06 to 0.07, all of which were significantly lower than that of Comparative Example 1. This can effectively reduce the interfacial friction resistance and operating temperature rise under high-speed transmission conditions, and improve transmission efficiency and high-temperature stability.

[0023] After a 150-hour durability test on a high-speed heavy-duty bench, the grease of this application can effectively inhibit chain wear and elongation. At the end of the test, the average chain elongation was only 2.220 mm, which is about 25.3% lower than that of Comparative Example 1 (2.970 mm). During long-term service, the lubricating film remains stable and does not fail, the degree of chain plastic deformation is lower, and the service life and transmission reliability are significantly improved.

[0024] The rust inhibitor and lubricating matrix in the formula work synergistically to form a film, creating a dense protective layer on the metal surface that effectively isolates moisture and corrosive media. Bench corrosion tests show that chains protected with the grease applied in this application exhibit no rust within 75 hours, and at the end of the 150-hour test, only 15 rust points were found, fewer than the 18 found in Comparative Example 1. The rust development rate is slower, demonstrating superior all-weather corrosion protection. Attached Figure Description

[0025] The attached diagram will be briefly described below:

[0026] Figure 1 The wear scar pattern is from Example 1 in Performance Test 1;

[0027] Figure 2 The wear pattern is shown in Example 2 of Performance Test 1;

[0028] Figure 3 The wear scar pattern is from Example 3 in Performance Test 1;

[0029] Figure 4 The wear pattern is shown in Comparative Example 1 of Performance Test 1.

[0030] Figure 5 The graph shows the average friction coefficient from performance test 2.

[0031] Figure 6 The curve showing the variation of G' / G'' with shear stress τ in performance test 3;

[0032] Figure 7 The curve showing the variation of shear stress τ with shear rate γ in performance test 3;

[0033] Figure 8 The curve showing the change in viscosity with shear rate γ in performance test 3. Detailed Implementation

[0034] The present application will now be further described by way of specific embodiments. Those skilled in the art will be able to implement the present application based on these descriptions. Furthermore, the embodiments of the present application described below are generally only a part of the embodiments of the present application, and not all of the embodiments. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present application without inventive effort should fall within the scope of protection of the present application.

[0035] Example 1

[0036] A method for preparing a lubricating grease includes the following steps:

[0037] S1. Preparation of base oil thickening fluid

[0038] Accurately weigh the following basic components according to the formula: 750g white oil, 600g pentaerythritol tetraethylhexanoate, 750g microcrystalline wax, and 300g polyisobutylene. Add all raw materials to a sealed reactor at once. Turn on the stirring device and heat to 160℃ at a uniform rate. After reaching the set temperature, continue stirring at a constant temperature for 90 minutes. During this process, under high temperature conditions, the polyisobutylene polymer chains fully untangle and extend, relying on thermal motion and mechanical shear force to undergo physical interpenetration cross-linking with the microcrystalline wax molecules. Simultaneously, the white oil and pentaerythritol tetraethylhexanoate are fully fused to form a uniform, stable, and highly elastic viscous base oil thickener, constructing the core support framework matrix of the grease, ensuring excellent adhesion and molding stability of the finished product. After stirring is complete, turn off the heating system and allow it to cool naturally for later use. The polyisobutylene comprises components with a molecular weight of 2×10⁻⁶. 4 ~1×10 5 Low molecular weight polyisobutylene (product model Oppanol® B10N), and molecular weight greater than 1×10 5 The high molecular weight polyisobutylene (product model Oppanol® N80); the mass ratio of the low molecular weight polyisobutylene to the high molecular weight polyisobutylene is 10:90.

[0039] S2, hierarchical composite reaction of multiphase functional components

[0040] After the temperature of the material inside the reactor naturally drops to 120℃, maintain a constant stirring speed, and employ a segmented feeding and staged stirring process, compounding various functional additives:

[0041] The first step involves adding the following solid functional components: 204g of nano-zinc oxide, 30g of polytetrafluoroethylene (PTFE) ultrafine powder (solid lubricant), and 60g of 2,6-di-tert-butyl-p-cresol (phenolic antioxidant). The mixture is then stirred continuously at a uniform speed for 30 minutes. This temperature range maximizes the wettability between the solid powder and the matrix, ensuring uniform dispersion of the zinc oxide and PTFE ultrafine powder in the viscoelastic matrix without agglomeration or sedimentation, thus initially forming a rust-preventive and self-lubricating functional system.

[0042] The second step involves adding liquid functional components: 150g of tricresyl nonyl phosphate (extreme pressure anti-wear agent), 150g of barium dinonylnaphthalenesulfonate (rust inhibitor), and 6g of T321 isobutylene sulfide (extreme pressure anti-wear agent). After addition, the mixture is continuously stirred at a constant temperature for 45 minutes. Under constant temperature conditions of approximately 120℃, isobutylene sulfide can undergo an in-situ chemical reaction with zinc oxide and other components in the formulation, efficiently generating inorganic products such as zinc sulfide. These reaction products possess ultra-high melting points, ultra-high hardness, and excellent interfacial adhesion properties, rapidly constructing a dense and robust protective film on the metal friction surface of the equipment. Through physical shielding, it completely isolates the direct contact between the metal friction pairs, reducing friction and wear at the source and preventing high-temperature sintering. Simultaneously, the various extreme pressure anti-wear components, rust inhibitors, and antioxidants within the system permeate and are fully compatible, uniformly dispersed within the viscoelastic matrix framework, achieving a synergistic balance of extreme pressure, anti-wear, rust prevention, and antioxidant systems to produce a lubricating grease.

[0043] Example 2

[0044] A method for preparing a lubricating grease includes the following steps:

[0045] S1. Preparation of base oil thickening fluid

[0046] Accurately weigh the following basic components according to the formula: 1050g white oil, 300g pentaerythritol tetraethylhexanoate, 750g microcrystalline wax, and 300g polyisobutylene. Add all raw materials to a sealed reactor at once. Turn on the stirring device and heat to 160℃ at a uniform rate. After reaching the set temperature, continue stirring at a constant temperature for 90 minutes. During this process, under high temperature conditions, the polyisobutylene polymer chains fully untangle and extend, relying on thermal motion and mechanical shear force to undergo physical interpenetration cross-linking with the microcrystalline wax molecules. Simultaneously, the white oil and pentaerythritol tetraethylhexanoate are fully fused to form a uniform, stable, and highly elastic viscous base oil thickener, constructing the core support framework matrix of the grease, ensuring excellent adhesion and molding stability of the finished product. After stirring is complete, turn off the heating system and allow it to cool naturally for later use. The polyisobutylene comprises components with a molecular weight of 2×10⁻⁶. 4 ~1×10 5 Low molecular weight polyisobutylene (product model Oppanol® B10N), and molecular weight greater than 1×10 5 The high molecular weight polyisobutylene (product model Oppanol® N80); the mass ratio of the low molecular weight polyisobutylene to the high molecular weight polyisobutylene is 10:90.

[0047] S2, hierarchical composite reaction of multiphase functional components

[0048] After the temperature of the material inside the reactor naturally drops to 120℃, maintain a constant stirring speed, and employ a segmented feeding and staged stirring process, compounding various functional additives:

[0049] The first step involves adding the following solid functional components: 210g zinc oxide, 30g polytetrafluoroethylene (PTFE) ultrafine powder (solid lubricant), and 60g 2,6-di-tert-butyl-p-cresol (phenolic antioxidant). The mixture is then stirred continuously at a uniform speed for 30 minutes. This temperature range maximizes the wettability between the solid powder and the matrix, ensuring uniform dispersion of the zinc oxide and PTFE ultrafine powder in the viscoelastic matrix without agglomeration or sedimentation, thus initially forming a rust-preventive and self-lubricating functional system.

[0050] The second step involves adding liquid functional components: 150g of T321 isobutylene sulfide (extreme pressure anti-wear agent) and 150g of barium dinonylnaphthalene sulfonate (rust inhibitor). After adding the materials, the mixture is stirred at a constant temperature for 45 minutes to obtain the grease.

[0051] Example 3

[0052] A method for preparing a lubricating grease includes the following steps:

[0053] S1. Preparation of base oil thickening fluid

[0054] Accurately weigh the following basic components according to the formula: 750g white oil, 600g pentaerythritol tetraethylhexanoate, 750g microcrystalline wax, and 300g polyisobutylene. Add all raw materials to a sealed reactor at once. Turn on the stirring device and heat to 160℃ at a uniform rate. After reaching the set temperature, continue stirring at a constant temperature for 90 minutes. During this process, under high temperature conditions, the polyisobutylene polymer chains fully untangle and extend, relying on thermal motion and mechanical shear force to undergo physical interpenetration cross-linking with the microcrystalline wax molecules. Simultaneously, the white oil and pentaerythritol tetraethylhexanoate are fully fused to form a uniform, stable, and highly elastic viscous base oil thickener, constructing the core support framework matrix of the grease, ensuring excellent adhesion and molding stability of the finished product. After stirring is complete, turn off the heating system and allow it to cool naturally for later use. The polyisobutylene comprises components with a molecular weight of 2×10⁻⁶. 4 ~1×10 5 Low molecular weight polyisobutylene (product model Oppanol® B10N), and molecular weight greater than 1×10 5 The high molecular weight polyisobutylene (product model Oppanol® N80); the mass ratio of the low molecular weight polyisobutylene to the high molecular weight polyisobutylene is 10:90.

[0055] S2, hierarchical composite reaction of multiphase functional components

[0056] After the temperature of the material inside the reactor naturally drops to 120℃, maintain a constant stirring speed, and employ a segmented feeding and staged stirring process, compounding various functional additives:

[0057] The first step involves adding the following solid functional components: 210g zinc oxide, 30g polytetrafluoroethylene (PTFE) ultrafine powder (solid lubricant), and 60g 2,6-di-tert-butyl-p-cresol (phenolic antioxidant). The mixture is then stirred continuously at a uniform speed for 30 minutes. This temperature range maximizes the wettability between the solid powder and the matrix, ensuring uniform dispersion of the zinc oxide and PTFE ultrafine powder in the viscoelastic matrix without agglomeration or sedimentation, thus initially forming a rust-preventive and self-lubricating functional system.

[0058] The second step involves adding liquid functional components: 150g of T321 isobutylene sulfide (extreme pressure anti-wear agent) and 150g of barium dinonylnaphthalene sulfonate (rust inhibitor). After adding the materials, the mixture is stirred at a constant temperature for 45 minutes to obtain the grease.

[0059] Comparative Example 1

[0060] This comparative example uses a commercially available high-performance grease, model NIGRIDER TN101L, manufactured by Nippon Oil Co., Ltd., which is a chain-specific grease.

[0061] Performance Test 1

[0062] This performance test examines the extreme pressure anti-wear load-bearing capacity of the lubricating grease. The test method is as follows: Following GB / T3142, a four-ball testing machine is used to measure the wear scar diameter of the steel balls under standard load of 392 N, speed of 1500 rpm, and time of 30 min. The test results are detailed in the table below. After the test, the steel ball samples were ultrasonically cleaned in acetone for 15 min, dried, and then characterized. The wear scar diameter was observed and measured using a VW-6000 three-dimensional morphology analysis system, and the results are summarized in the table below.

[0063] Table 1 Test results of wear scar diameter

[0064] Example 1 0.255 Example 2 0.397 Example 3 0.339 Comparative Example 1 0.375

[0065] Please refer to the table above and the appendix. Figures 1-4 It can be observed that the wear scar diameter of the grease in Example 1 of this invention is only 0.255 mm, which is significantly reduced by approximately 32.0% compared to the 0.375 mm of the commercially available product in Comparative Example 1. Examples 2 and 3, due to the absence of tricresyl nonyl phosphate, have slightly lower anti-wear performance than Example 1, with wear scar diameters of 0.397 mm and 0.339 mm respectively, and their overall effect is similar to Comparative Example 1. Meanwhile, the wear scar diameter of the greases cited in the background art is 0.36~0.38 mm. Example 1 of this application reduces the wear scar diameter by approximately 29.2% compared to the lowest value of 0.36 mm and by approximately 32.9% compared to the highest value of 0.38 mm, demonstrating a significant improvement in extreme pressure anti-wear performance. It is evident that this application, through the selection of raw materials and the synergistic effect between them, has significantly improved lubrication performance, exhibiting unexpected technical effects.

[0066] Performance Test 2

[0067] This performance test evaluates the extreme pressure anti-wear and load-bearing capacity of the greases in the examples and comparative examples. A ball-to-ball contact friction mode was used, with GCr15 bearing steel balls (12.7 mm diameter, Rockwell hardness 60 HRC) as the friction pair. The friction-reducing and anti-wear properties of the greases were systematically investigated using an MMW-1 friction and wear testing machine manufactured by Jinan Testing Group. The main test index was the coefficient of friction. The test conditions were: standard load 392 N, speed 1200 rpm, and test time 30 min.

[0068] Please see the appendix Figure 5 The average friction coefficient of Example 1 was stable in the range of 0.03 to 0.04, the average friction coefficient of Example 2 was 0.055 to 0.065, the average friction coefficient of Example 3 was 0.06 to 0.07, and the average friction coefficient of Comparative Example 1 was 0.07 to 0.085. Based on the median value of 0.075 in Comparative Example 1, the average friction coefficient of Example 1 decreased by more than 50%, and the temperature rise at the friction pair interface was lower, demonstrating significant friction reduction and temperature control effects.

[0069] Performance Test 3

[0070] This performance test examined the structural strength and shear stability of the greases in Examples 1-3 and Comparative Example 1 by measuring their storage modulus G′ and loss modulus G″. The test method involved oscillatory rheological testing using a rheometer to determine the modulus and yield stress. The rheological test conditions were as follows: test mode: oscillatory shear; test temperature: 20℃; oscillation frequency (f): 1.000Hz, corresponding to an angular frequency (ω) of 6.2832 rad / s; strain distribution mode: logarithmic distribution (Log); shear stress range (τ0): initial stress 0.1000 Pa (corresponding to a torque of 1.123 μNm), final stress 1200.0 Pa (corresponding to a torque of 1.347 × 10⁻⁶ Pa). 4 μNm).

[0071] Please see the appendix Figure 6 The initial values ​​of the storage modulus G′ of the lubricating greases in Examples 1-3 all exceeded 10. 4 Pa is significantly higher than the loss modulus G″, and G′ is always greater than G″ over a wide range of shear stresses, indicating that the gel structure of the grease of the present invention is intact and has high mechanical strength. In contrast, the modulus curve of Comparative Example 1 is lower than that of Example 1, indicating that its structural strength and stability are weaker than those of the grease of Example 1, and it is more prone to structural damage and loss under high shear conditions.

[0072] Please see the appendix Figure 7The shear stress curve of Example 1 is the lowest overall, stabilizing at about 800~1000 Pa. Example 3 is next, while the shear stress of Example 2 and Comparative Example 1 is significantly higher. This indicates that the greases of Examples 1 and 3 have lower yield stress, making it easier to form a uniform lubricating film at the interface of the friction pair, resulting in better pumpability and low-temperature start-up performance. In contrast, Comparative Example 1 has a high yield stress, which can easily lead to greater starting resistance and increased energy consumption.

[0073] Please see the appendix Figure 8 The viscosity of Example 1 decreased most significantly with increasing shear rate, eventually stabilizing at about 10 Pa·s. Example 2 was next, while the final viscosity of Example 3 and Comparative Example 1 was even higher. This indicates that the greases of Examples 1 and 2 of the present invention have better shear-thinning characteristics and can effectively reduce frictional resistance and temperature rise under high-speed shear conditions. In contrast, Comparative Example 1 has poor viscosity retention and is prone to insufficient viscosity and lubrication failure under high shear conditions.

[0074] Performance Test 4

[0075] This performance test comprehensively evaluated the wear resistance, elongation, and long-term rust prevention performance of the greases from Example 1 and Comparative Example 1 under high-speed, heavy-load conditions using a bench test. The test method is as follows: A 520H specification chain was immersed in the grease of this invention at 130~150℃ for 5~15s. Utilizing the thermal fluidity and capillary effect of the grease, the components containing zinc oxide, PTFE, and extreme pressure additives were allowed to fully penetrate into the micron-level gaps between the chain pins and rollers. After removal and drying, as the temperature decreased, the viscoelastic matrix constructed by polyisobutylene and microcrystalline wax in the grease regained its structural strength, locking the grease components inside the friction pairs. The average immersion amount of the chain was controlled at 4.0±1g. The test equipment was a chain abrasion tester. The total number of test chain links was 120L, and the number of measured links was 49L. The speed was set to 1600 r / min, the load was 1.80 kN, and the chain was run continuously for 150 h. The average elongation, elongation rate, and number of surface rust spots of the chain were recorded at 25 h, 50 h, 75 h, 100 h, 125 h, and 150 h, respectively. The results are shown in the table below.

[0076] Table 2 Bench Test Results

[0077] initial 0 0 0 0 25H 0.185 0.365 0 0 50H 0.320 0.555 0 0 75H 0.340 0.635 1 0 100H 0.745 0.695 2 0 125H 1.460 1.420 6 7 150H 2.970 2.220 18 15

[0078] Referring to the table above, it can be seen that under high-speed, heavy-load, continuous operation conditions, the lubricating grease of Embodiment 1 of the present invention can effectively improve the chain's resistance to pressure and wear, and inhibit the wear elongation of the chain after long-term operation.

[0079] In the early stage of the test, the chain elongation of Example 1 was slightly higher than that of Comparative Example 1. As the running time was extended to 100 hours, the chain elongation rate of Example 1 slowed down significantly, and the elongation gradually became lower than that of Comparative Example 1. When the test ended at 150 hours, the average elongation of the chain of Comparative Example 1 reached 2.970 mm, while that of Example 1 was only 2.220 mm. The total elongation of the chain after long-term operation was significantly reduced.

[0080] This indicates that the grease of the present invention can form a stable and durable lubricating protective film on the surface of the chain friction pair, effectively reducing the friction and wear between the pin and the roller, slowing down the plastic deformation and wear elongation of the chain after long-term service, and exhibiting better pressure resistance, wear resistance and long-term wear resistance stability under long-term high-speed heavy load conditions.

[0081] Regarding long-term rust prevention, the grease of Example 1 of this invention exhibits superior protective performance. During the test, the chain of Comparative Example 1 showed rust after 75 hours, and the number of rust sites increased rapidly with prolonged operation, reaching 18 rust sites at the end of the test; while the chain of Example 1 showed no early rust, with only 15 rust sites at the end of the test, indicating a slower rate of rust development. This demonstrates that the grease of this invention can form a dense and continuous protective film on the chain surface, effectively isolating it from external corrosive media, and possesses excellent long-term rust prevention and corrosion resistance, significantly extending the service life of the chain.

Claims

1. A method for preparing a lubricating grease, characterized in that, Includes the following steps: S1, base oil, microcrystalline wax and polyisobutylene are melt-mixed to obtain a base oil thickened liquid; S2. Add zinc oxide, isobutylene sulfide, solid lubricant, phenolic antioxidant and rust inhibitor to the base oil thickener, and stir at 120~130℃ to obtain grease; The total amount of raw materials for preparing the grease is 100 parts by weight, and the amounts of each component are as follows: 35-60 parts base oil, 25-50 parts thickening binder, 5-15 parts extreme pressure anti-wear agent, 0.5-8 parts solid lubricant, 0.5-3 parts phenolic antioxidant, and 1-8 parts rust inhibitor; the thickening binder includes microcrystalline wax and polyisobutylene, and the extreme pressure anti-wear agent includes zinc oxide and sulfide isobutylene.

2. The method for preparing a lubricating grease according to claim 1, characterized in that, The polyisobutylene comprises a molecular weight of 2×10⁻⁶. 4 ~1×10 5 Low molecular weight polyisobutylene, and those with a molecular weight greater than 1×10 5 The high molecular weight polyisobutylene; the mass ratio of the low molecular weight polyisobutylene to the high molecular weight polyisobutylene is (5~15):(85~95).

3. The method for preparing a lubricating grease according to claim 1, characterized in that, The base oil comprises white oil and pentaerythritol tetraethylhexanoate, wherein the mass ratio of white oil to pentaerythritol tetraethylhexanoate is (4~6):(3~5).

4. The method for preparing a lubricating grease according to claim 1, characterized in that, The mass ratio of the microcrystalline wax to polyisobutylene is (4~6):(3~5).

5. The method for preparing a lubricating grease according to claim 1, characterized in that, The extreme pressure anti-wear agent also includes tricresol nonyl phosphate; the mass ratio of zinc oxide, tricresol nonyl phosphate and isobutylene sulfide is (30~40):(20~30):(0.5~2).

6. The method for preparing a lubricating grease according to claim 1, characterized in that, Step S2 includes: first, adding zinc oxide, solid lubricant, and phenolic antioxidant to the base oil thickening solution, stirring to obtain the reaction solution; then adding tricresyl nonyl phosphate, isobutylene sulfide, and rust inhibitor to the reaction solution to obtain the grease.

7. The method for preparing a lubricating grease according to claim 1, characterized in that, The solid lubricant is polytetrafluoroethylene, the rust inhibitor is barium dinonylnaphthalenesulfonate, and the phenolic antioxidant is 2,6-di-tert-butyl-p-cresol.

8. The method for preparing a lubricating grease according to claim 1, characterized in that, The melting and mixing temperature in step S1 is 150~180℃.

9. A lubricating grease, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the lubricating grease according to claim 9 in transmission friction components, reciprocating sliding components, and meshing kinematic pairs.

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