A self-healing lubricating composition, a method for preparing it, and an engine oil containing the composition.

Abstract

This invention belongs to the technical field of self-healing lubricants, specifically relating to a self-healing lubricating composition, its preparation method, and an engine oil containing the composition. The lubricating composition, by mass percentage, comprises: 6.0-12.0% dynamically cross-linked polyether ester elastomer, 3.0-6.0% thermally induced release microcapsules, 1.0-4.0% graphene-coated molybdenum disulfide composite, 2.0-5.0% fluorinated polyether modified silicone oil, 0.5-1.5% polyamine polymer derivative, 0.2-0.8% iron-based organic complex, 0.8-2.5% phosphate ester extreme pressure additive, 0.5-2.0% esterified polyether dispersant and stabilizer, and 0.2-1.2% aniline and phenolic composite antioxidant components, with the balance being synthetic base oil. The preparation method includes staged heating, shear dispersion, and isothermal stirring steps. The lubricating composition of this invention exhibits excellent anti-wear, anti-oxidation, and stable film-forming properties, making it suitable for lubrication systems in high-temperature and high-shear environments, and conforms to the requirements of green and low-carbon development.

Description

Technical Field

[0001] This invention belongs to the technical field of self-healing lubricants, specifically relating to a self-healing lubricating composition, a preparation method thereof, and an engine oil containing the composition. Background Technology

[0002] As a key material in the operation of mechanical equipment, lubricating oil is mainly used to reduce direct contact between friction pairs and maintain the stability of equipment operation. Under high-load conditions such as automobile engines, heavy machinery, and wind turbine main shafts, lubricating oil faces multiple operating conditions including high temperature, high pressure, shearing, and oxidation. The molecular structure of the lubricant is prone to change, leading to a decline in lubrication performance, which can further cause wear, surface fatigue, and even equipment failure.

[0003] Existing lubricating compositions primarily enhance the thermal stability and service life of lubricating oils by adding components such as extreme pressure anti-wear agents, antioxidants, dispersants, and detergents. However, these additives are prone to decomposition or consumption during long-term use, and once the lubricating film is damaged, it is difficult to repair itself, making it difficult to meet the lubrication requirements of equipment operating under harsh conditions for extended periods.

[0004] In recent years, self-healing materials have been gradually introduced into the field of lubrication technology, achieving the self-recovery process of the lubricating layer by constructing molecular structure systems with chemical or physical responsive capabilities. However, existing self-healing lubricating compositions mostly rely on single-type microcapsule structures or simplified cross-linked polymer systems, which still have significant limitations in structural stability, repair efficiency, and dispersion compatibility. In addition, in composite lubrication systems, some additives are prone to mutual interference, reducing the overall formulation stability and performance durability.

[0005] Therefore, there is an urgent need to provide a novel self-healing lubricating composition with a more complex composition, higher compatibility, and structural stability and multi-level synergistic effect in high-temperature shearing environments, along with corresponding preparation processes and application ratio methods, to solve the technical problems of existing lubricants such as easy degradation, lack of durability, and lubrication failure under complex working conditions. Summary of the Invention

[0006] To address the aforementioned problems, the present invention aims to provide a self-healing lubricating composition, comprising, by weight percentage: 6.0-12.0% dynamically cross-linked polyether ester elastomer; 3.0-6.0% thermally induced release microcapsules; 1.0-4.0% graphene-coated molybdenum disulfide composite; 2.0-5.0% fluorinated polyether modified silicone oil; 0.5-1.5% polyamine polymer derivative; 0.2-0.8% iron-based organic complex; 0.8-2.5% phosphate ester extreme pressure additive; 0.5-2.0% esterified polyether dispersant and stabilizer; 0.2-1.2% aniline and phenolic composite antioxidant component; and synthetic base oil to make up to -100%.

[0007] In a preferred embodiment, the dynamically cross-linked polyether ester elastomer is formed by polycondensation of a polyether segment with a diene structure at the end and an aliphatic dicarboxylic acid diol polymer with an ester bond in the middle. Its weight average molecular weight is between 15,000 and 30,000, and the degree of cross-linking is controlled within the range of 0.05 to 0.15 mol per gram of polymer.

[0008] In a preferred embodiment, the thermally induced release microcapsule uses a polyurea shell prepared by polycondensation of isocyanate and polyamine, with a particle size range of 150-350 nanometers, and the coating material is linear dimethyl silicone oil, with a core-shell mass ratio of 4:1-6:1.

[0009] Specifically, the introduction of thermally induced release microcapsules plays a crucial responsive role in lubricated environments. When the lubricated pair is under high friction and high heat load conditions, the microcapsule shell (a polyurea structure formed by the condensation of isocyanate and polyamine) undergoes thermally responsive expansion or rupture under localized heating conditions, thereby releasing the linear dimethyl silicone oil encapsulated inside. This type of silicone oil has good lubricity and fluidity, and can rapidly diffuse to the damaged interface to replenish the lubricating film that has failed due to shearing or wear.

[0010] Meanwhile, the dynamically cross-linked polyether ester elastomer contains reversible diene cross-linking points and compliant polyether segments in its molecular structure, and its cross-linked network has a "break-reconstruction" capability. When microscopic damage occurs, the cross-linking points in the network break after being subjected to heat or mechanical stress, but the polymer segments can quickly recombine and cross-link at new locations to form a new network structure, exhibiting a certain degree of self-healing properties.

[0011] Polyamine polymer derivatives, as multifunctional reaction media, possess a flexible main chain, abundant branches, high ammonia value, and good polar affinity. In the cross-linked network, they can reversibly bind with ester and hydroxyl groups in the elastomer through hydrogen bonding or electrostatic interactions, enhancing the system's toughness and local adhesion. On the other hand, they can also complex and adsorb with silicone oil or other polar components released from microcapsules, forming a more stable interfacial structure.

[0012] The synergistic mechanism among the three is as follows:

[0013] Microcapsules locally release silicone oil under frictional heat, acting as an "instant repair fluid" to achieve temperature-controlled response and local release; elastomers provide a mobile cross-linked network to rapidly reconstruct the structure in the damaged area; polyamine polymer branches insert into crack gaps or fracture points to achieve interlocking support and intermolecular adsorption, thereby achieving polar guidance and gap filling.

[0014] Ultimately, a self-healing microstructure network with the ability to slow release, embed, and reconstruct is constructed on the surface of the lubricated pair, which effectively resists the damage of the lubricating film and at the same time slows down the wear evolution process, thereby improving the durability and intelligent response capability of the lubricating composition under complex working conditions.

[0015] In a preferred embodiment, the graphene-coated molybdenum disulfide composite has a 2H crystal form and the graphene has a sheet structure of five layers or less. The two are composited by high-energy ball milling, with the particle size controlled at 80-180 nanometers, and the surface is carboxylated before use.

[0016] Specifically, the graphene-coated molybdenum disulfide composite utilizes the synergistic structural properties of two two-dimensional layered materials to significantly improve the continuity and coverage of the lubricating film. Its lubrication enhancement principle is mainly reflected in:

[0017] Both molybdenum disulfide (MoS2) and graphene are typical layered crystal structures, characterized by strong in-plane atomic bonding and weak interlayer forces. On the surface of a friction pair, they readily slide along the shear direction, thus forming a physical lubricating layer with an extremely low coefficient of friction. This reduces wear and resistance between metal contact surfaces, achieving the low shear properties of the layered structure.

[0018] After high-energy ball milling, graphene sheets tightly coat the surface of MoS2 particles, forming composite particles of suitable size and high stability. This structure not only prevents MoS2 from agglomerating and settling in oil, but also utilizes the high specific surface area and strong adsorption of graphene to improve the dispersion stability of the composite particles in lubricating oil and the adsorption density on the friction surface, thereby enhancing dispersion and orientation through the coating structure.

[0019] Under shear stress or thermal load, composite particles are prone to rearrangement along the friction direction. Graphene and MoS2 are stacked together to form a "layer-by-layer" lubricating band, which not only extends the lateral extension range of the lubrication effect of a single particle, but also enhances the continuity and adhesion of the lubricating film (i.e., constructing a continuous lubricating film), so that the lubricating protective layer can cover the contact surface more extensively and uniformly.

[0020] In a preferred embodiment, the fluorinated polyether modified silicone oil is a block copolymer with a main chain containing siloxane bonds and side chains incorporating fluorinated vinyl groups and polyether segments. Its molecular weight ranges from 3000 to 6000 Daltons, and the mass ratio of oleophilic to hydrophilic ends is 4:1 to 7:1.

[0021] In a preferred embodiment, the polyamine polymer derivative is a polyetheramine with an average ammonia value greater than 300 mg potassium hydroxide per gram, and its structure contains one to three aliphatic amine branches, the main chain is a repeating unit of polypropylene glycol or polybutylene glycol, and the monomer indirection length is 3-5 repeating units.

[0022] In a preferred embodiment, the iron-based organic complex is a paramagnetic Fe(III) complex, the ligand of which is derived from the condensation product of alkyd resin condensate and small molecule organic acid containing hydroxyl and carboxyl groups, with a coordination ratio of 1:2 or 1:3.

[0023] In a preferred embodiment, the phosphate ester extreme pressure additive is triisopropyl phosphate or trinonyl phosphate, and the amount added is 1.2-2.2% of the total mass of the lubricating composition, and the acid value is controlled at 120-160 mg potassium hydroxide per gram.

[0024] The present invention also provides a method for preparing the lubricating composition, comprising the following steps:

[0025] S1. Mix the dynamic cross-linked polyether ester elastomer with the base oil in an inert atmosphere, heat to 50-60 degrees Celsius, and stir for 30 minutes to form a homogeneous solution.

[0026] S2. Add fluorinated polyether modified silicone oil and polyamine polymer derivative in sequence, and stir for 40 minutes;

[0027] S3. Add microcapsules, graphene-coated molybdenum disulfide complex and iron-based organic complex to the mixture and disperse at 8000 rpm for 20 minutes.

[0028] S4. Finally, add phosphate ester extreme pressure additives, esterified polyether dispersant stabilizers and composite antioxidant components, stir until the system is transparent and uniform, cool to room temperature and then seal and store.

[0029] The present invention also provides an engine oil containing the self-healing lubricating composition, wherein the lubricating composition is added to a synthetic lubricating oil whose base oil is a mixture of polyalphaolefin and diester at a mass percentage of 1.5-8.0%, and the engine oil meets the technical standards of SAE viscosity grade 5W-30 or 10W-40.

[0030] Beneficial effects

[0031] The self-healing lubricating composition of this invention maintains component stability under harsh conditions such as high temperature and high shear, effectively delaying the decline in lubrication performance. The introduction of thermally induced release microcapsules, combined with dynamically cross-linked polyether ester elastomers and polyamine polymer derivatives, forms a tightly interlocked cross-linked network, improving the mechanical structural integrity of the lubricating medium.

[0032] The graphene-coated molybdenum disulfide composite exhibits a layered structure, enhancing the coverage of the lubricating film. The molecular ratio between the fluorinated polyether-modified silicone oil and the iron-based organic complex ensures good adhesion of the lubricating medium to the metal surface. The combination of phosphate ester extreme pressure additives and composite antioxidant components controls the rate of thermal oxidative degradation.

[0033] The lubricating composition described in this invention does not require frequent replacement during use, reducing resource consumption and waste oil emissions. Some components, such as esterified polyether and polyether ester elastomer, are readily biodegradable materials, and the entire system is free of environmentally sensitive components such as chlorinated paraffin and zinc ash residue, exhibiting excellent environmental adaptability. The overall formulation aligns with the development direction of green lubricating materials, facilitating the promotion and application of low-carbon lubrication technology in transportation, heavy equipment, and other industries, demonstrating significant environmental value and promising engineering applications. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the method flow of the present invention;

[0035] Figure 2 This is a schematic diagram showing the comparative experimental results (wear resistance) of the present invention.

[0036] Figure 3 This is a schematic diagram of the comparative experimental results (extreme pressure performance) of the present invention;

[0037] Figure 4 This is a schematic diagram showing the comparative experimental results (lubricating film retention) of the present invention;

[0038] Figure 5 This is a schematic diagram showing the comparative experimental results (thermal oxidation stability) of the present invention;

[0039] Figure 6 This is a schematic diagram showing the comparative experimental results (high temperature and high shear stability) of the present invention;

[0040] Figure 7 This is a schematic diagram showing the comparative experimental results (self-healing ability) of the present invention. Detailed Implementation

[0041] To enhance understanding of the present invention, the present invention will be further described in detail below with reference to embodiments. These embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0042] Example 1 (T1)

[0043] This embodiment provides a self-healing lubricating composition, the components and their proportions by mass percentage as follows:

[0044] Dynamically cross-linked polyether ester elastomer: 6.0%;

[0045] Thermally induced release microcapsules: 3.0%;

[0046] Graphene-coated molybdenum disulfide composite: 1.0%;

[0047] Fluorinated polyether modified silicone oil: 2.0%;

[0048] Polyamine polymer derivatives: 0.5%;

[0049] Iron-based organic complexes: 0.2%;

[0050] Phosphate ester extreme pressure additives: 0.8%;

[0051] Esterified polyether type dispersant stabilizer: 0.5%;

[0052] Aniline and phenolic compound antioxidant component: 0.2%;

[0053] Synthetic base oil: Top up to 100%.

[0054] Preparation method reference Figure 1 As shown, the specific steps are as follows:

[0055] S1. Under inert atmosphere, weigh the dynamically cross-linked polyether ester elastomer at the specified mass ratio, add it to 70.8% synthetic base oil, control the temperature at 55 degrees Celsius, stir for 30 minutes to form a homogeneous solution.

[0056] S2. Add 2.0% of fluorinated polyether modified silicone oil and 0.5% of polyamine polymer derivative in sequence, and continue stirring for 40 minutes while maintaining a constant temperature.

[0057] S3. Add 3.0% thermally induced release microcapsules, 1.0% graphene-coated molybdenum disulfide complex and 0.2% iron-based organic complex, and shear disperse at 8000 rpm for 20 minutes using a high-shear disperser. The resulting mixture maintains good flowability and homogeneity.

[0058] S4. At 60 degrees Celsius, add 0.8% of phosphate ester extreme pressure additive, 0.5% of esterified polyether type dispersant and stabilizer, and 0.2% of aniline and phenolic composite antioxidant component, and continue stirring for 30 minutes to obtain a transparent and uniform lubricating composition. Cool to room temperature and store in a sealed container.

[0059] The resulting composition was added at 6.0% by mass to a synthetic motor oil based on a mixture of polyalphaolefin and diester. After thorough mixing, the resulting motor oil had a viscosity grade of SAE 5W-30.

[0060] Specifically, the introduction of thermally induced release microcapsules plays a crucial responsive role in lubricated environments. When the lubricated pair is under high friction and high heat load conditions, the microcapsule shell (a polyurea structure formed by the condensation of isocyanate and polyamine) undergoes thermally responsive expansion or rupture under localized heating conditions, thereby releasing the linear dimethyl silicone oil encapsulated inside. This type of silicone oil has good lubricity and fluidity, and can rapidly diffuse to the damaged interface to replenish the lubricating film that has failed due to shearing or wear.

[0061] Meanwhile, the dynamically cross-linked polyether ester elastomer contains reversible diene cross-linking points and compliant polyether segments in its molecular structure, and its cross-linked network has a "break-reconstruction" capability. When microscopic damage occurs, the cross-linking points in the network break after being subjected to heat or mechanical stress, but the polymer segments can quickly recombine and cross-link at new locations to form a new network structure, exhibiting a certain degree of self-healing properties.

[0062] Polyamine polymer derivatives, as multifunctional reaction media, possess a flexible main chain, abundant branches, high ammonia value, and good polar affinity. In the cross-linked network, they can reversibly bind with ester and hydroxyl groups in the elastomer through hydrogen bonding or electrostatic interactions, enhancing the system's toughness and local adhesion. On the other hand, they can also complex and adsorb with silicone oil or other polar components released from microcapsules, forming a more stable interfacial structure.

[0063] The synergistic mechanism among the three is as follows:

[0064] Microcapsules locally release silicone oil under frictional heat, acting as an "instant repair fluid" to achieve temperature-controlled response and local release; elastomers provide a mobile cross-linked network to rapidly reconstruct the structure in the damaged area; polyamine polymer branches insert into crack gaps or fracture points to achieve interlocking support and intermolecular adsorption, thereby achieving polar guidance and gap filling.

[0065] Ultimately, a self-healing microstructure network with the ability to slow release, embed, and reconstruct is constructed on the surface of the lubricated pair, which effectively resists the damage of the lubricating film and at the same time slows down the wear evolution process, thereby improving the durability and intelligent response capability of the lubricating composition under complex working conditions.

[0066] Example 2 (T2)

[0067] This embodiment provides a self-healing lubricating composition, the components and their proportions by mass percentage as follows:

[0068] Dynamically cross-linked polyether ester elastomer: 12.0%;

[0069] Thermo-induced release microcapsules: 6.0%;

[0070] Graphene-coated molybdenum disulfide composite: 4.0%;

[0071] Fluorinated polyether modified silicone oil: 5.0%;

[0072] Polyamine polymer derivatives: 1.5%;

[0073] Iron-based organic complexes: 0.8%;

[0074] Phosphate ester extreme pressure additives: 2.5%;

[0075] Esterified polyether type dispersant stabilizer: 2.0%;

[0076] Aniline and phenolic compound antioxidant components: 1.2%;

[0077] Synthetic base oil: Top up to 100%.

[0078] The preparation process is as follows:

[0079] S1. Under nitrogen protection, take 12.0% of the dynamically cross-linked polyether ester elastomer and add it to the synthetic base oil. Then, add 65.0% of the base oil in proportion, ensuring the total mass is 100%. Heat the system to 60 degrees Celsius and stir for 30 minutes to form a homogeneous solution.

[0080] S2. Under constant temperature conditions, add 5.0% of fluorinated polyether modified silicone oil and 1.5% of polyamine polymer derivative in sequence, and continue stirring for 40 minutes to ensure that the solutions of each phase are fully mixed.

[0081] S3. Add 6.0% thermally induced release microcapsules, 4.0% graphene-coated molybdenum disulfide complex and 0.8% iron-based organic complex, and disperse for 20 minutes using a high-shear device with a shear rate of 8000 rpm to obtain a uniformly distributed semi-transparent dispersion system.

[0082] S4. Add 2.5% of phosphate ester extreme pressure additive, 2.0% of esterified polyether type dispersant and stabilizer, and 1.2% of aniline and phenolic composite antioxidant at 60 degrees Celsius. Stir for 30 minutes and observe that the mixture is uniform and transparent. Then cool to room temperature, seal and store to obtain the final lubricating composition.

[0083] The self-healing lubricating composition was added at 8.0% by mass to a synthetic engine oil composed of polyalphaolefin and diester base oil. After homogenization and mixing, the resulting engine oil met the SAE 5W-30 viscosity grade requirements.

[0084] Example 3 (T3)

[0085] This embodiment provides a self-healing lubricating composition, the components and their proportions by mass percentage as follows:

[0086] Dynamically cross-linked polyether ester elastomer: 9.0%;

[0087] Thermally induced release microcapsules: 4.5%;

[0088] Graphene-coated molybdenum disulfide composite: 2.5%;

[0089] Fluorinated polyether modified silicone oil: 3.5%;

[0090] Polyamine polymer derivatives: 1.0%;

[0091] Iron-based organic complexes: 0.5%;

[0092] Phosphate ester extreme pressure additives: 1.8%;

[0093] Esterified polyether type dispersant stabilizer: 1.2%;

[0094] Aniline and phenolic compound antioxidant component: 0.7%;

[0095] Synthetic base oil: Top up to 100%.

[0096] The preparation steps are as follows:

[0097] S1. Under nitrogen protection, weigh 9.0% of the dynamically cross-linked polyether ester elastomer and add it to the synthetic base oil. Initially add 68.3% of the synthetic base oil. Heat the total system to 55 degrees Celsius and keep it in a uniform dissolution state for 30 minutes under mechanical stirring to form a premixed system.

[0098] S2. Add 3.5% of fluorinated polyether modified silicone oil and 1.0% of polyamine polymer derivative in sequence, and continue stirring at a constant temperature of 55 degrees Celsius for 40 minutes to obtain a homogeneous dispersed phase.

[0099] S3. Add 4.5% of thermally induced release microcapsules, 2.5% of graphene-coated molybdenum disulfide complex and 0.5% of iron-based organic complex to the mixture in sequence, and disperse the mixture for 20 minutes at 8000 rpm using a high-shear device to ensure uniform particle distribution and avoid local aggregation.

[0100] S4. Continue to add 1.8% of phosphate ester extreme pressure additive, 1.2% of esterified polyether type dispersant and stabilizer and 0.7% of aniline and phenolic composite antioxidant to the mixed system, stir at a constant temperature for 30 minutes until the liquid is clear and transparent, cool to room temperature and then seal and store to obtain the lubricating composition.

[0101] The prepared lubricating composition was added to a synthetic engine oil based on a mixture of polyalphaolefin and diester at a mass percentage of 5.0%. After thorough mixing, the viscosity grade of the engine oil was tested and found to be SAE 5W-30.

[0102] Comparative Example 1 (C1)

[0103] This comparative example provides a comparative lubricating composition, the components and their proportions by mass percentage as follows:

[0104] Dynamically cross-linked polyether ester elastomer: 4.0%;

[0105] Thermally induced release microcapsules: 2.0%;

[0106] Graphene-coated molybdenum disulfide composite: 1.0%;

[0107] Fluorinated polyether modified silicone oil: 6.0%;

[0108] Polyamine polymer derivatives: 0.3%;

[0109] Phosphate ester extreme pressure additive: 0.5%;

[0110] Esterified polyether type dispersant stabilizer: 0.3%;

[0111] Aniline and phenolic compound antioxidant component: 0.1%;

[0112] Synthetic base oil: Top up to 100%.

[0113] The preparation method is the same as in Example 3 (T3), including: preheating and stirring of the base oil, staged mixing of each additive, high-shear dispersion, and isothermal stabilization treatment. The final lubricating composition is a light gray opaque liquid at room temperature, and slight sedimentation occurs after standing for 24 hours.

[0114] Comparative Example 2 (C2)

[0115] This comparative example provides a lubricating composition for comparison, the components and their proportions by mass percentage as follows:

[0116] Dynamically cross-linked polyether ester elastomer: 13.5%;

[0117] Thermally induced release microcapsules: 2.5%;

[0118] Graphene-coated molybdenum disulfide composite: 0.8%;

[0119] Fluorinated polyether modified silicone oil: 2.5%;

[0120] Polyamine polymer derivatives: 1.8%;

[0121] Iron-based organic complexes: 0.2%;

[0122] Phosphate ester extreme pressure additives: 3.2%;

[0123] Esterified polyether type dispersant stabilizer: 0.4%;

[0124] Aniline and phenolic compound antioxidant component: 0.4%;

[0125] Synthetic base oil: Top up to 100%.

[0126] The preparation method is the same as in Example 3 (T3), including heating and dissolving, adding in stages, shearing and dispersing, and constant temperature stirring.

[0127] Comparative Example 3 (C3)

[0128] This comparative example provides a conventional lubricating oil formulation widely used in the prior art, used as a control experiment. Its components and proportions, by mass percentage, are as follows:

[0129] Mineral base oil (hydrocracking Group II): 92.5%;

[0130] Polyisobutylene tackifier: 4.0%;

[0131] Zinc dialkyl dithiophosphate (ZDDP): 1.0%;

[0132] Dialkyldiphenylamine antioxidants: 0.5%;

[0133] Aniline-based detergent: 0.5%;

[0134] Phosphate ester type extreme pressure additive: 0.5%;

[0135] Polymethyl methacrylate pour point depressant: 1.0%.

[0136] This formulation is prepared by mechanical mixing and low-temperature pre-dissolution. It is a light yellow transparent liquid at room temperature. The additive system used is mainly composed of ZDDP and aromatic amine antioxidants, and does not contain any thermally responsive structural units, self-healing materials or nano-lubricating fillers.

[0137] Comparative Example 4 (C4)

[0138] This comparative example provides a common fully synthetic base oil formulation lubricant, used as a prior art control sample, comprising the following components by mass percentage:

[0139] Polyalphaolefin (PAO-6 and PAO-40 blended in a 1:1 ratio): 88.0%;

[0140] Diester (diisononyl adipate): 5.0%;

[0141] Organic molybdenum-based friction modifier: 0.5%;

[0142] Zinc dialkyl dithiophosphate (ZDDP): 1.2%;

[0143] Phosphate ester type extreme pressure agent: 1.0%;

[0144] Benzotriazole copper inhibitor: 0.3%;

[0145] Aniline and phenolic compound antioxidant: 1.5%;

[0146] Detergent dispersant (high alkalinity calcium sulfonate): 2.5%.

[0147] The preparation method is as follows: under vacuum stirring conditions, the components are added to the base oil system in sequence, stirred evenly, filtered and set aside for later use.

[0148] Comparative experiment:

[0149] Experimental objective: To systematically compare the differences between the examples (T1, T2, T3) and the comparative samples (C1, C2, C3, C4) in several key lubrication performance indicators, and to verify the technical advantages of the lubricating composition of the present invention in terms of structural stability, self-healing and adaptability to high temperature and high shear environments.

[0150] The experimental groups are shown in Table 1:

[0151] Table 1 Comparative Experiment Groups

[0152] Grouping Sample Name Feature Description T1 Example 1 Each component is used with the lower limit ratio. T2 Example 2 Each component adopts the upper limit ratio. T3 Example 3 Each component adopts an optimal intermediate ratio. C1 Comparative Example 1 If the proportion of dynamic polymer is too low, the film formation will be unstable. C2 Comparative Example 2 Excess of some components leads to structural imbalance. C3 Comparative Example 3 Traditional mineral oil formulations lack self-healing and nanofiller properties. C4 Comparative Example 4 Conventional fully synthetic oil formulation, without structure-responsive components

[0153] Test items and methods

[0154] 1. Wear resistance test:

[0155] Referring to ASTM D4172 standard, a four-ball friction tester was used to run for 60 minutes at a load of 392 N, a speed of 1200 rpm, and a temperature of 75°C. The diameter of the wear scars on the three steel balls was measured to evaluate the anti-wear performance of the lubricating oil.

[0156] 2. Extreme pressure performance test:

[0157] According to ASTM D2783 standard, the four-ball extreme pressure method was used to apply load step by step, and the maximum non-seize load (PB value) of the lubricant was recorded to determine its extreme pressure bearing capacity.

[0158] 3. Lubricating film retention test:

[0159] The SRV tribometer was used to monitor the oil film rupture time for 60 minutes under conditions of 100℃, 200 N load, and 50 Hz frequency to evaluate the stability and continuity of the lubricating film.

[0160] 4. Thermal oxidation stability test:

[0161] The oxidation induction time of the samples was measured in minutes using a pressure differential scanning calorimeter (PDSC) in an oxygen environment at 210°C, reflecting their resistance to oxidative aging.

[0162] 5. High-temperature and high-shear stability test:

[0163] The high-temperature high-shear viscosity (HTHS value) of lubricating oil was determined according to ASTM D6278 at 150°C: the sample was measured at a shear rate of 10⁻¹⁰ using a cone-cylinder viscometer at 150°C. 6The dynamic viscosity at s⁻¹ was used to evaluate its viscosity retention performance under high-temperature operating conditions.

[0164] 6. Self-healing capability test:

[0165] After scratching the surface of a stainless steel specimen (15 μm deep), it was immersed in lubricating oil and left to stand at 80°C for 24 hours. An optical profilometer was used to observe whether there were obvious signs of backfilling or contour recovery of the scratches, in order to determine whether it had self-healing ability.

[0166] The experimental results are shown in Table 2:

[0167] Table 2 Comparison of experimental results

[0168] Grouping Wear scar diameter (mm) PB value (N) Oil film retention time (min) Oxidation induction time (min) HTHS viscosity (mPa·s) Scratch depth (μm) T1 0.45 820 38 82 3.3 5.6 T2 0.38 920 52 101 3.61 3.4 T3 0.4 880 47 93 3.48 4.1 C1 0.72 610 21 63 2.77 10.9 C2 0.68 670 25 68 2.94 8.7 C3 0.63 730 22 57 2.65 12.3 C4 0.51 850 29 76 3.02 11

[0169] Data Analysis

[0170] From the perspective of wear scar diameter, such as Figure 2 As shown, Examples T1 to T3 all exhibited good anti-wear performance, with T2 showing the smallest wear scar at 0.38 mm, which was better than T1 (0.45 mm) and T3 (0.40 mm), and significantly better than comparative samples C1 to C4 (wear scar range 0.51-0.72 mm). This demonstrates that the lubricating composition of the present invention can effectively slow down metal-to-metal contact wear when properly formulated.

[0171] In terms of extreme pressure performance, such as Figure 3 As shown, measured by the maximum non-seize load (PB value), T2 reaches 920 N, T3 and T1 are 880 N and 820 N respectively, all significantly higher than C1 (610 N), C2 (670 N) and C3 (730 N), and slightly higher than the existing synthetic oil comparison C4 (850 N), indicating that the multi-component synergistic structure of the present invention has higher stability under load pressure conditions.

[0172] Regarding the retention time of the lubricating film, such as Figure 4 As shown, T2 reaches 52 minutes, T3 and T1 are 47 minutes and 38 minutes respectively, which are much higher than C1 to C3 (minimum 21 minutes) and C4 (29 minutes), reflecting that the self-healing structural unit and dispersion system can maintain an effective lubrication state for a longer time during friction.

[0173] In thermal oxidation stability tests, such as Figure 5 As shown, the induction time for T2 was 101 minutes, while T3 and T1 were 93 minutes and 82 minutes, respectively, all of which were higher than those of the comparative groups C1 to C4 (the lowest being 57 minutes). This indicates that the antioxidant components and polymeric framework structure in this invention can effectively improve the oxidation durability at high temperatures.

[0174] In terms of high temperature high shear viscosity (HTHS), such as Figure 6 As shown, T2 is 3.61 mPa·s, T3 and T1 are 3.48 and 3.30 mPa·s respectively, all of which are better than the comparative example group (C1 to C4 are between 2.65-3.02 mPa·s), indicating that the lubricating composition of the present invention has a stronger viscosity retention ability under high shear environment and is not easily diluted and thinned.

[0175] In terms of self-repair capabilities, such as Figure 7 As shown, after standing at 80℃, the scratch depth of T2 was only 3.4 μm, which was significantly better than T3 (4.1 μm) and T1 (5.6 μm). The scratch depths of C1 to C4 were all greater than 8.0 μm, and some even exceeded 10 μm. No scratch edge contour backfilling or bulging was observed. This indicates that the dynamic cross-linked elastomer and microcapsule structure introduced in this invention help to reconstruct and respond to repair surface defects.

[0176] In summary, Examples T1 to T3, especially T2, outperformed the comparative sample in all key performance indicators, verifying the comprehensive technical advantages of the self-healing lubricating composition in terms of wear resistance, high temperature resistance, high shear stability, and structural responsiveness. These results fully support the effectiveness and innovation of the technical solution of this invention.

[0177] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A self-healing lubricating composition, characterized in that, By mass percentage, it includes the following components: The dynamically cross-linked polyether ester elastomer comprises 6.0-12.0%; the dynamically cross-linked polyether ester elastomer is formed by the condensation polymerization of a polyether segment with a diene structure at the end and an aliphatic diacid diol polymer with an ester bond in the middle, with a weight average molecular weight between 15,000 and 30,000, and a degree of cross-linking controlled within the range of 0.05-0.15 mol per gram of polymer. Thermo-induced release microcapsules 3.0-6.0%; the thermo-induced release microcapsules are made of polyurea shell prepared by polycondensation of isocyanate and polyamine, with a particle size range of 150-350 nm, and the coating material is linear dimethyl silicone oil, with a core-shell mass ratio of 4:1-6:1; Graphene-coated molybdenum disulfide composites: 1.0-4.0%; Fluorinated polyether modified silicone oil 2.0-5.0%; 0.5-1.5% of polyamine polymer derivatives; the polyamine polymer derivatives are polyetheramines with an average ammonia value greater than 300 mg potassium hydroxide per gram, and their structure contains one to three aliphatic amine branches, the main chain is a repeating unit of polypropylene glycol or polybutane glycol, and the monomer indirect length is 3-5 repeating units. Iron-based organic complex 0.2-0.8%; the iron-based organic complex is a paramagnetic Fe(III) complex, whose ligands are derived from the condensation products of alkyd resin condensate and small molecule organic acids containing hydroxyl and carboxyl groups, with a coordination ratio of 1:2 or 1:

3. Phosphate ester extreme pressure additives: 0.8-2.5%; Esterified polyether type dispersant stabilizer 0.5-2.0%; Aniline and phenolic compound antioxidant components: 0.2-1.2%; Synthetic base oil is used to replenish the balance.

2. The self-healing lubricating composition according to claim 1, characterized in that, In the graphene-coated molybdenum disulfide composite, the molybdenum disulfide has a 2H crystal form, and the graphene has a sheet structure of less than five layers. The two are composited by high-energy ball milling, with the particle size controlled at 80-180 nanometers, and the surface is carboxylated before use.

3. The self-healing lubricating composition according to claim 1, characterized in that, The fluorinated polyether modified silicone oil is a block copolymer with siloxane bonds in the main chain and fluorinated vinyl groups and polyether segments introduced into the side chains. Its molecular weight ranges from 3000 to 6000 Daltons, and the mass ratio of oleophilic to hydrophilic ends is 4:1 to 7:

1.

4. The self-healing lubricating composition according to claim 1, characterized in that, The phosphate ester extreme pressure additive is triisopropyl phosphate or trinonyl phosphate, and the amount added is 1.2-2.2% of the total mass of the lubricating composition, and the acid value is controlled at 120-160 mg potassium hydroxide per gram.

5. The method for preparing the lubricating composition according to any one of claims 1-4, characterized in that, Includes the following steps: S1. Mix the dynamic cross-linked polyether ester elastomer with the base oil in an inert atmosphere, heat to 50-60 degrees Celsius, and stir for 30 minutes to form a homogeneous solution. S2. Add fluorinated polyether modified silicone oil and polyamine polymer derivative in sequence, and stir for 40 minutes; S3. Add microcapsules, graphene-coated molybdenum disulfide complex and iron-based organic complex to the mixture and disperse at 8000 rpm for 20 minutes. S4. Add phosphate ester extreme pressure additives, esterified polyether type dispersant stabilizers and composite antioxidant components, stir until the system is transparent and uniform, cool to room temperature and then seal and store.

6. An engine oil containing the self-healing lubricating composition as described in any one of claims 1-4, characterized in that, The lubricating composition is added to a synthetic engine oil whose base oil is a mixture of polyalphaolefin and diester at a mass percentage of 1.5-8.0%, and the engine oil meets the technical standards of SAE viscosity grade 5W-30 or 10W-40.

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