Environment-friendly lubricating grease and preparation method thereof

Abstract

The application discloses an environment-friendly lubricating grease and a preparation method thereof, and relates to the technical field of lubricating grease, which is composed of the following components in parts by weight: shape memory high polymer 2.5-3.5 parts, metal-based shape memory alloy nanoparticles 1.2-1.8 parts, double-response type composite intelligent additive 3.5-5.5 parts, composite base oil 76-81 parts, supramolecular thickening agent 11-12 parts and self-repairing microcapsule 2.5-3.5 parts. The environment-friendly lubricating grease is composed of shape memory high polymer, metal-based shape memory alloy nanoparticles, double-response type composite intelligent additive, composite base oil, supramolecular thickening agent and self-repairing microcapsule, compared with the prior art, the comprehensive performance of the lubricating grease can be improved, the adaptability of the lubricating grease under different working conditions can be enhanced, the lubricating effect can be improved, and the self-repairing capacity can be improved, so that the problem that the performance of traditional lubricating grease is single and the traditional lubricating grease is difficult to meet the demand of complex working conditions can be solved.

Description

Technical Field

[0001] This invention relates to the field of lubricating grease technology, specifically to an environmentally friendly lubricating grease and its preparation method. Background Technology

[0002] Grease forms a durable lubricating film on the surface of mechanical friction pairs, reducing direct contact between metals, thereby reducing friction and wear and preventing corrosion of parts. It also functions as a sealant to prevent dust, buffer shocks and dampen vibrations, ensuring the smooth operation of mechanical equipment and extending its service life.

[0003] In existing technologies, environmentally friendly greases have poor adaptability to complex working conditions, unsatisfactory lubrication effects, and insufficient self-healing capabilities, which greatly limits their application in various harsh working environments and makes it difficult to meet the comprehensive performance requirements of mechanical equipment. Therefore, this invention provides an environmentally friendly grease and its preparation method. Summary of the Invention

[0004] The purpose of this invention is to provide an environmentally friendly lubricating grease and its preparation method. This invention uses shape memory polymer, metal-based shape memory alloy nanoparticles, dual-response composite intelligent additives, composite base oil, supramolecular thickener, and self-healing microcapsules as raw materials to enable the components to work synergistically, thereby preparing an environmentally friendly lubricating grease. This lubricating grease has stronger adaptability under different working conditions, better lubrication effect, and good self-healing ability, which can meet the needs of complex working conditions.

[0005] To achieve the above objectives, the present invention provides the following technical solution: An environmentally friendly lubricating grease is composed of the following materials in parts by weight: 2.5-3.5 parts of shape memory polymer, 1.2-1.8 parts of metal-based shape memory alloy nanoparticles, 3.5-5.5 parts of dual-response composite intelligent additive, 76-81 parts of composite base oil, 11-12 parts of supramolecular thickener, and 2.5-3.5 parts of self-healing microcapsules; The shape memory polymer is prepared from the following materials in parts by weight: 53-57 parts polylactic acid, 43-47 parts polycaprolactone, and 1.6-2.4 parts crosslinking agent; The metal-based shape memory alloy nanoparticles are prepared from the following materials in parts by weight: 99.2-99.3 parts of nickel-titanium alloy target and 0.7-0.8 parts of niobium; The dual-response composite smart additive is prepared from the following materials in parts by weight: 63-67 parts of pH-sensitive polymer microspheres and 33-37 parts of shear-sensitive nanosheets; The composite base oil is prepared from the following materials in parts by weight: 40 parts rapeseed oil, 60 parts polyol ester, and 0.16-0.24 parts nanocellulose whiskers; The supramolecular thickener is prepared from the following materials in parts by weight: 12-13 parts of β-cyclodextrin, 63-67 parts of polycaprolactone monomer and 22-23 parts of polyethylene glycol monomer; The self-healing microcapsule is prepared from the following materials in parts by weight: 82-83 parts of wall material raw material and 17-18 parts of repair agent, wherein the wall material raw material contains polydopamine-polyethylene glycol block copolymer and the repair agent contains nano-aluminum powder and silane coupling agent.

[0006] A preferred method for preparing environmentally friendly lubricating grease includes the following steps: Step S1: Mix refined rapeseed oil and polyol esters in a certain proportion to obtain a composite base oil; Step S2: Add nano-cellulose whiskers to the composite base oil and disperse them ultrasonically; Step S3: Prepare supramolecular thickener precursor and add it to the composite base oil to react, so that it self-assembles to form nanomicelles and three-dimensional network structures; Step S4: Prepare metal-based shape memory alloy nanoparticles and dop them, then add them to the system treated in step S3 and stir until homogeneous; Step S5: Prepare a dual-response composite smart additive and add it to the system treated in step S4, and continue stirring; Step S6: Dissolve the shape memory polymer and add it dropwise to the system treated in step S5 to react and form a network structure; Step S7: After preparing self-healing microcapsules and determining the grafting rate, add them to the system treated in step S5 and stir evenly to obtain environmentally friendly lubricating grease.

[0007] Preferably, step S1 further includes the following steps: Step S11: The rapeseed oil is refined using a combination of molecular distillation and supercritical fluid extraction to achieve an unsaturated fatty acid content of 93.2%–93.8% in the refined rapeseed oil. Step S12: Mix the refined rapeseed oil and pentaerythritol ester at a ratio of 4:6 at 56-64°C until homogeneous.

[0008] Preferably, step S2 further includes the following steps: Step S21: Weigh 0.16 to 0.24 parts of nanocellulose whiskers with an aspect ratio of 65 to 85 as a viscosity modifier; Step S22: Add nanocellulose whiskers to the composite base oil and ultrasonically disperse for 42-48 minutes to ensure uniform dispersion.

[0009] Preferably, step S3 further includes the following steps: Step S31: Mix β-cyclodextrin, polycaprolactone monomer, and polyethylene glycol monomer, add stannous octoate (0.1%–0.3% of the total mass of the mixture), and react at 120–140°C for 4–6 hours to prepare a supramolecular thickener precursor. This supramolecular thickener has β-cyclodextrin as the core and is grafted with 5 polycaprolactone-polyethylene glycol block chains. Step S32: Add the supramolecular thickener precursor to the composite base oil and stir the reaction at 86-94°C for 2.6-3.4 hours. By adjusting the block length ratio, the molecules self-assemble to form nanomicelles with a diameter of 65-85 nm and construct a three-dimensional network structure.

[0010] Preferably, step S4 further includes the following steps: Step S41: Select a nickel-titanium alloy target with an atomic ratio of nickel to titanium of 49.2:50.8 to 49.8:50.2, and prepare metal-based shape memory alloy nanoparticles by magnetron sputtering. Step S42: The prepared metal-based shape memory alloy nanoparticles are doped with 0.7-0.8 atomic% niobium using a high-energy ball milling method. After treatment, the nanoparticles are added to the system treated in step S3 and stirred evenly.

[0011] Preferably, step S5 further includes the following steps: Step S51: Prepare polyacrylic acid-polyethylene glycol graft copolymer microspheres with a particle size of 160-240 nm as pH-sensitive polymer microspheres, and molybdenum disulfide nanosheets with a thickness of 7-8 nm and a sheet diameter of 220-380 nm as shear-sensitive nanosheets. Step S52: Mix 63-67 parts of pH-sensitive polymer microspheres with 33-37 parts of shear-sensitive nanosheets to obtain a dual-response composite smart additive, and then add it to the system treated in step S4, and continue stirring for 1.3-1.7 hours.

[0012] Preferably, step S6 further includes the following steps: Step S61: Select a crosslinking product based on polylactic acid-polycaprolactone block copolymer as the shape memory polymer, with a glass transition temperature of 23-27℃ and a crystallinity of 33%-37%; Step S62: Dissolve the shape memory polymer in dichloromethane at a mass ratio of 1:5 to 1:8, and then add it dropwise to the system treated in step S5. Stir the reaction at 36 to 44°C for 3.6 to 4.4 hours to allow the shape memory polymer to form a network structure in the system.

[0013] Preferably, step S7 further includes the following steps: Step S71: Self-healing microcapsules were prepared using atom transfer radical polymerization technology. Polydopamine-polyethylene glycol block copolymer was grafted onto the surface of the microcapsule wall material. The self-healing microcapsule wall thickness was 62-68 nm, the rupture pressure was 120-130 Pa, and the mass ratio of nano-aluminum powder to silane coupling agent in the core was 4.2:1-4.8:1. Step S72: After the self-healing microcapsules are prepared, the grafting rate of the polydopamine-polyethylene glycol block copolymer is determined by nuclear magnetic resonance spectroscopy. The grafting rate is set to 23% to 27%. The copolymer is then added to the system treated in step S6 and stirred until homogeneous to obtain an environmentally friendly lubricating grease.

[0014] Preferably, step S7 further includes the following steps: Step S73: When preparing self-healing microcapsules, control the reaction temperature at 46-54°C and maintain the reaction temperature for 6.6-7.4 hours.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention utilizes an environmentally friendly lubricating grease composed of shape memory polymers, metal-based shape memory alloy nanoparticles, dual-responsive composite intelligent additives, composite base oils, supramolecular thickeners, and self-healing microcapsules. This achieves synergistic effects among the components, improving the overall performance of the lubricating grease compared to existing technologies. It enhances the grease's adaptability under different working conditions, improves lubrication, and enhances its self-healing capabilities. Therefore, it can solve the problem of traditional lubricating greases having limited performance and failing to meet the needs of complex working conditions.

[0016] 2. This invention refines rapeseed oil using a combination of molecular distillation and supercritical extraction in the preparation method, and controls the reaction temperature, time, and material ratio in each step. This achieves precise control over the microstructure and properties of the lubricating grease. Compared with existing technologies, this invention can improve the stability and consistency of product quality, while increasing production efficiency and reducing energy consumption. Therefore, it can solve the problems of large fluctuations in product quality, high energy consumption, and low efficiency in traditional preparation processes.

[0017] 3. This invention optimizes the performance of self-healing microcapsules by employing atom transfer radical polymerization technology in the preparation of the self-healing microcapsules and controlling the reaction temperature, time, and grafting rate. Compared with existing technologies, it can improve the self-healing efficiency and durability of greases and effectively extend their service life. Therefore, it can solve the problem that traditional greases are difficult to repair effectively after wear during use, leading to premature equipment damage. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention have been clearly and completely described. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] This embodiment provides an environmentally friendly lubricating grease, which is composed of the following materials in parts by weight: 2.5 to 3.5 parts of shape memory polymer, 1.2 to 1.8 parts of metal-based shape memory alloy nanoparticles, 3.5 to 5.5 parts of dual-response composite intelligent additive, 76 to 81 parts of composite base oil, 11 to 12 parts of supramolecular thickener, and 2.5 to 3.5 parts of self-healing microcapsules; The shape memory polymer is prepared from the following materials in parts by weight: 53-57 parts polylactic acid, 43-47 parts polycaprolactone, and 1.6-2.4 parts crosslinking agent; The metal-based shape memory alloy nanoparticles were prepared from the following materials in parts by weight: 99.2–99.3 parts of nickel-titanium alloy target and 0.7–0.8 parts of niobium; The dual-response composite smart additive is prepared from the following materials in parts by weight: 63-67 parts of pH-sensitive polymer microspheres and 33-37 parts of shear-sensitive nanosheets; The composite base oil is prepared from the following materials in parts by weight: 40 parts rapeseed oil, 60 parts polyol ester, and 0.16 to 0.24 parts nanocellulose whiskers; The supramolecular thickener is prepared from the following materials in parts by weight: 12-13 parts of β-cyclodextrin, 63-67 parts of polycaprolactone monomer and 22-23 parts of polyethylene glycol monomer; The self-healing microcapsules are prepared from the following materials in parts by weight: 82-83 parts of wall material raw material and 17-18 parts of repair agent, wherein the wall material raw material contains polydopamine-polyethylene glycol block copolymer and the repair agent contains nano-aluminum powder and silane coupling agent.

[0020] In some embodiments, the method for preparing environmentally friendly lubricating grease includes the following steps: Step S1: Mix refined rapeseed oil and polyol esters in a certain proportion to obtain a composite base oil; Step S2: Add nano-cellulose whiskers to the composite base oil and disperse them ultrasonically; Step S3: Prepare supramolecular thickener precursor and add it to the composite base oil to react, so that it self-assembles to form nanomicelles and three-dimensional network structures; Step S4: Prepare metal-based shape memory alloy nanoparticles and dop them, then add them to the system treated in step S3 and stir until homogeneous; Step S5: Prepare a dual-response composite smart additive and add it to the system treated in step S4, and continue stirring; Step S6: Dissolve the shape memory polymer and add it dropwise to the system treated in step S5 to react and form a network structure; Step S7: After preparing self-healing microcapsules and determining the grafting rate, add them to the system treated in step S5 and stir evenly to obtain environmentally friendly lubricating grease.

[0021] In some embodiments, step S1 further includes the following steps: Step S11: The rapeseed oil is refined using a combination of molecular distillation and supercritical fluid extraction to achieve an unsaturated fatty acid content of 93.2%–93.8% in the refined rapeseed oil. Step S12: Mix the refined rapeseed oil and pentaerythritol ester at a ratio of 4:6 at 56-64°C until homogeneous.

[0022] In some embodiments, step S2 further includes the following steps: Step S21: Weigh 0.16 to 0.24 parts of nanocellulose whiskers with an aspect ratio of 65 to 85 as a viscosity modifier; Step S22: Add nanocellulose whiskers to the composite base oil and ultrasonically disperse for 42-48 minutes to ensure uniform dispersion.

[0023] In some embodiments, step S3 further includes the following steps: Step S31: Mix β-cyclodextrin, polycaprolactone monomer, and polyethylene glycol monomer, add stannous octoate (0.1%–0.3% of the total mass of the mixture), and react at 120–140°C for 4–6 hours to prepare a supramolecular thickener precursor. This supramolecular thickener has β-cyclodextrin as the core and is grafted with 5 polycaprolactone-polyethylene glycol block chains. Step S32: Add the supramolecular thickener precursor to the composite base oil and stir the reaction at 86-94°C for 2.6-3.4 hours. By adjusting the block length ratio, the molecules self-assemble to form nanomicelles with a diameter of 65-85 nm and construct a three-dimensional network structure.

[0024] In some embodiments, step S4 further includes the following steps: Step S41: Select a nickel-titanium alloy target with an atomic ratio of nickel to titanium of 49.2:50.8 to 49.8:50.2, and prepare metal-based shape memory alloy nanoparticles by magnetron sputtering. Step S42: The prepared metal-based shape memory alloy nanoparticles are doped with 0.7-0.8 atomic% niobium using a high-energy ball milling method. After treatment, the nanoparticles are added to the system treated in step S3 and stirred evenly.

[0025] In some embodiments, step S5 further includes the following steps: Step S51: Prepare polyacrylic acid-polyethylene glycol graft copolymer microspheres with a particle size of 160-240 nm as pH-sensitive polymer microspheres, and molybdenum disulfide nanosheets with a thickness of 7-8 nm and a sheet diameter of 220-380 nm as shear-sensitive nanosheets. Step S52: Mix 63-67 parts of pH-sensitive polymer microspheres with 33-37 parts of shear-sensitive nanosheets to obtain a dual-response composite smart additive, and then add it to the system treated in step S4, and continue stirring for 1.3-1.7 hours.

[0026] In some embodiments, step S6 further includes the following steps: Step S61: Select a crosslinking product based on polylactic acid-polycaprolactone block copolymer as the shape memory polymer, with a glass transition temperature of 23-27℃ and a crystallinity of 33%-37%; Step S62: Dissolve the shape memory polymer in dichloromethane at a mass ratio of 1:5 to 1:8, and then add it dropwise to the system treated in step S5. Stir the reaction at 36 to 44°C for 3.6 to 4.4 hours to allow the shape memory polymer to form a network structure in the system.

[0027] In some embodiments, step S7 further includes the following steps: Step S71: Self-healing microcapsules were prepared using atom transfer radical polymerization technology. Polydopamine-polyethylene glycol block copolymer was grafted onto the surface of the microcapsule wall material. The self-healing microcapsule wall thickness was 62-68 nm, the rupture pressure was 120-130 Pa, and the mass ratio of nano-aluminum powder to silane coupling agent in the core was 4.2:1-4.8:1. Step S72: After the self-healing microcapsules are prepared, the grafting rate of the polydopamine-polyethylene glycol block copolymer is determined by nuclear magnetic resonance spectroscopy. The grafting rate is set to 23% to 27%. The copolymer is then added to the system treated in step S6 and stirred until homogeneous to obtain an environmentally friendly lubricating grease.

[0028] In some embodiments, step S7 further includes the following steps: Step S73: When preparing self-healing microcapsules, control the reaction temperature at 46-54°C and maintain the reaction temperature for 6.6-7.4 hours.

[0029] Based on the foregoing embodiments, the following sets of experiments were conducted: It should be noted that the raw materials used in the following embodiments are all commercially available.

[0030] Example 1: An environmentally friendly lubricating grease, composed of the following materials in parts by weight: 3.0 parts of shape memory polymer, 1.5 parts of metal-based shape memory alloy nanoparticles, 4.5 parts of dual-response composite intelligent additive, 78 parts of composite base oil, 11.5 parts of supramolecular thickener, and 3.0 parts of self-healing microcapsules; The shape memory polymer is prepared from the following materials in parts by weight: 55 parts polylactic acid, 45 parts polycaprolactone, and 2.0 parts crosslinking agent; The metal-based shape memory alloy nanoparticles were prepared from the following materials in parts by weight: 99.25 parts nickel-titanium alloy target and 0.75 parts niobium; The dual-response composite smart additive is prepared from the following materials in parts by weight: 65 parts of pH-sensitive polymer microspheres and 35 parts of shear-sensitive nanosheets; The composite base oil is prepared from the following materials in parts by weight: 40 parts rapeseed oil, 60 parts polyol ester, and 0.20 parts nanocellulose whiskers; The supramolecular thickener is prepared from the following materials in parts by weight: 12.5 parts β-cyclodextrin, 65 parts polycaprolactone monomer, and 22.5 parts polyethylene glycol monomer; The self-healing microcapsules are prepared from the following materials in parts by weight: 82.5 parts of wall material raw material and 17.5 parts of repair agent, wherein the wall material raw material contains polydopamine-polyethylene glycol block copolymer and the repair agent contains nano-aluminum powder and silane coupling agent.

[0031] The preparation method of environmentally friendly lubricating grease includes the following steps: Step S1: Mix refined rapeseed oil and polyol esters in a certain proportion to obtain a composite base oil; Step S1 also includes the following steps: Step S11: The rapeseed oil is refined using a combination of molecular distillation and supercritical fluid extraction technology, resulting in a refined rapeseed oil with an unsaturated fatty acid content of 93.5%. Step S12: Mix the refined rapeseed oil and pentaerythritol ester at a ratio of 4:6 at 60°C until homogeneous.

[0032] Step S2: Add nano-cellulose whiskers to the composite base oil and disperse them ultrasonically; Step S2 also includes the following steps: Step S21: Weigh 0.20 parts of nanocellulose whiskers with an aspect ratio of 75 as a viscosity modifier; Step S22: Add nanocellulose whiskers to the composite base oil and ultrasonically disperse for 45 minutes to ensure uniform dispersion.

[0033] Step S3: Prepare supramolecular thickener precursor and add it to the composite base oil to react, so that it self-assembles to form nanomicelles and three-dimensional network structures; Step S3 also includes the following steps: Step S31: Mix β-cyclodextrin, polycaprolactone monomer, and polyethylene glycol monomer, add stannous octoate (0.2% of the total mass of the mixture), and react at 130°C for 5 hours to prepare a supramolecular thickener precursor. This supramolecular thickener has β-cyclodextrin as the core and is grafted with 5 polycaprolactone-polyethylene glycol block chains. Step S32: Add the supramolecular thickener precursor to the composite base oil and stir at 90°C for 3.0 hours. By adjusting the block length ratio, the molecules self-assemble to form nanomicelles with a diameter of 75 nm and construct a three-dimensional network structure.

[0034] Step S4: Prepare metal-based shape memory alloy nanoparticles and dop them, then add them to the system treated in step S3 and stir until homogeneous; Step S4 also includes the following steps: Step S41: Select a nickel-titanium alloy target with an atomic ratio of nickel to titanium of 49.5:50.5, and prepare metal-based shape memory alloy nanoparticles by magnetron sputtering. Step S42: The prepared metal-based shape memory alloy nanoparticles are doped with 0.75 atomic% niobium using a high-energy ball milling method. After treatment, the nanoparticles are added to the system treated in step S3 and stirred evenly.

[0035] Step S5: Prepare a dual-response composite smart additive and add it to the system treated in step S4, and continue stirring; Step S5 also includes the following steps: Step S51: Prepare polyacrylic acid-polyethylene glycol graft copolymer microspheres with a particle size of 200 nm as pH-sensitive polymer microspheres, and molybdenum disulfide nanosheets with a thickness of 7.5 nm and a sheet diameter of 300 nm as shear-sensitive nanosheets. Step S52: Mix 65 parts of pH-sensitive polymer microspheres and 35 parts of shear-sensitive nanosheets evenly to obtain a dual-response composite smart additive, and then add it to the system treated in step S4, and continue stirring for 1.5 hours.

[0036] Step S6: Dissolve the shape memory polymer and add it dropwise to the system treated in step S5 to react and form a network structure; Step S6 also includes the following steps: Step S61: Select the crosslinking product based on polylactic acid-polycaprolactone block copolymer as the shape memory polymer, with a glass transition temperature of 25℃ and a crystallinity of 35%; Step S62: Dissolve the shape memory polymer in dichloromethane at a mass ratio of 1:6.5 and then add it dropwise to the system treated in step S5. Stir the reaction at 40°C for 4.0 hours to allow the shape memory polymer to form a network structure in the system.

[0037] Step S7: After preparing self-healing microcapsules and determining the grafting rate, add them to the system treated in step S6 and stir evenly to obtain environmentally friendly lubricating grease.

[0038] Step S7 also includes the following steps: Step S71: Self-healing microcapsules were prepared using atom transfer radical polymerization technology. Polydopamine-polyethylene glycol block copolymer was grafted onto the surface of the microcapsule wall material. The self-healing microcapsule wall thickness was 65 nm, the rupture pressure was 125 Pa, and the mass ratio of nano-aluminum powder to silane coupling agent in the core was 4.5:1. Step S72: After the self-healing microcapsules are prepared, the grafting rate of the polydopamine-polyethylene glycol block copolymer is determined by nuclear magnetic resonance spectroscopy. The grafting rate is set to 25%, and the copolymer is added to the system treated in step S6 and stirred evenly to obtain an environmentally friendly lubricating grease.

[0039] Step S73: When preparing self-healing microcapsules, control the reaction temperature at 50°C and maintain the reaction temperature for 7.0 hours.

[0040] Example 2: An environmentally friendly lubricating grease, composed of the following materials in parts by weight: 2.5 parts shape memory polymer, 1.2 parts metal-based shape memory alloy nanoparticles, 3.5 parts dual-response composite intelligent additive, 76 parts composite base oil, 11 parts supramolecular thickener, and 2.5 parts self-healing microcapsules; The shape memory polymer is prepared from the following materials in parts by weight: 53 parts polylactic acid, 43 parts polycaprolactone, and 1.6 parts crosslinking agent; The metal-based shape memory alloy nanoparticles were prepared from the following materials in parts by weight: 99.2 parts nickel-titanium alloy target and 0.7 parts niobium; The dual-response composite smart additive is prepared from the following materials in parts by weight: 63 parts of pH-sensitive polymer microspheres and 33 parts of shear-sensitive nanosheets; The composite base oil is prepared from the following materials in parts by weight: 40 parts rapeseed oil, 60 parts polyol ester, and 0.16 parts nanocellulose whiskers; The supramolecular thickener is prepared from the following materials in parts by weight: 12 parts β-cyclodextrin, 63 parts polycaprolactone monomer, and 22 parts polyethylene glycol monomer; The self-healing microcapsules are prepared from the following materials in parts by weight: 82 parts of wall material raw material and 17 parts of repair agent, wherein the wall material raw material contains polydopamine-polyethylene glycol block copolymer and the repair agent contains nano-aluminum powder and silane coupling agent.

[0041] The preparation method of environmentally friendly lubricating grease includes the following steps: Step S1: Mix refined rapeseed oil and polyol esters in a certain proportion to obtain a composite base oil; Step S1 also includes the following steps: Step S11: The rapeseed oil is refined using a combination of molecular distillation and supercritical fluid extraction technology, resulting in a refined rapeseed oil with an unsaturated fatty acid content of 93.2%. Step S12: Mix the refined rapeseed oil and pentaerythritol ester at a ratio of 4:6 at 56°C until homogeneous.

[0042] Step S2: Add nano-cellulose whiskers to the composite base oil and disperse them ultrasonically; Step S2 also includes the following steps: Step S21: Weigh 0.16 parts of nanocellulose whiskers with an aspect ratio of 65 as a viscosity modifier; Step S22: Add nanocellulose whiskers to the composite base oil and ultrasonically disperse for 42 minutes to ensure uniform dispersion.

[0043] Step S3: Prepare supramolecular thickener precursor and add it to the composite base oil to react, so that it self-assembles to form nanomicelles and three-dimensional network structures; Step S3 also includes the following steps: Step S31: Mix β-cyclodextrin, polycaprolactone monomer, and polyethylene glycol monomer, add stannous octoate (0.1% of the total mass of the mixture), and react at 120°C for 4 hours to prepare a supramolecular thickener precursor. This supramolecular thickener has β-cyclodextrin as the core and is grafted with 5 polycaprolactone-polyethylene glycol block chains. Step S32: Add the supramolecular thickener precursor to the composite base oil and stir at 86°C for 2.6 hours. By adjusting the block length ratio, the molecules self-assemble to form nanomicelles with a diameter of 65 nm and construct a three-dimensional network structure.

[0044] Step S4: Prepare metal-based shape memory alloy nanoparticles and dop them, then add them to the system treated in step S3 and stir until homogeneous; Step S4 also includes the following steps: Step S41: Select a nickel-titanium alloy target with an atomic ratio of nickel to titanium of 49.2:50.8, and prepare metal-based shape memory alloy nanoparticles by magnetron sputtering. Step S42: The prepared metal-based shape memory alloy nanoparticles are doped with 0.7 atomic% niobium using a high-energy ball milling method. After treatment, the nanoparticles are added to the system treated in step S3 and stirred evenly.

[0045] Step S5: Prepare a dual-response composite smart additive and add it to the system treated in step S4, and continue stirring; Step S5 also includes the following steps: Step S51: Prepare polyacrylic acid-polyethylene glycol graft copolymer microspheres with a particle size of 160 nm as pH-sensitive polymer microspheres, and molybdenum disulfide nanosheets with a thickness of 7 nm and a sheet diameter of 220 nm as shear-sensitive nanosheets. Step S52: Mix 63 parts of pH-sensitive polymer microspheres and 33 parts of shear-sensitive nanosheets evenly to obtain a dual-response composite smart additive, and then add it to the system treated in step S4, and continue stirring for 1.3 hours.

[0046] Step S6: Dissolve the shape memory polymer and add it dropwise to the system treated in step S5 to react and form a network structure; Step S6 also includes the following steps: Step S61: Select the crosslinking product based on polylactic acid-polycaprolactone block copolymer as the shape memory polymer, with a glass transition temperature of 23℃ and a crystallinity of 33%; Step S62: Dissolve the shape memory polymer in dichloromethane at a mass ratio of 1:5, and then add it dropwise to the system treated in step S5. Stir the reaction at 36°C for 3.6 hours to allow the shape memory polymer to form a network structure in the system.

[0047] Step S7: After preparing self-healing microcapsules and determining the grafting rate, add them to the system treated in step S6 and stir evenly to obtain environmentally friendly lubricating grease.

[0048] Step S7 also includes the following steps: Step S71: Self-healing microcapsules were prepared using atom transfer radical polymerization technology. Polydopamine-polyethylene glycol block copolymer was grafted onto the surface of the microcapsule wall material. The self-healing microcapsule wall thickness was 62 nm, the rupture pressure was 120 Pa, and the mass ratio of nano-aluminum powder to silane coupling agent in the core was 4.2:1. Step S72: After the self-healing microcapsules are prepared, the grafting rate of the polydopamine-polyethylene glycol block copolymer is determined by nuclear magnetic resonance spectroscopy. The grafting rate is set to 23%. The copolymer is then added to the system treated in step S6 and stirred evenly to obtain an environmentally friendly lubricating grease.

[0049] Step S73: When preparing self-healing microcapsules, the reaction temperature is controlled at 46°C and maintained for 6.6 hours.

[0050] Example 3: An environmentally friendly lubricating grease, composed of the following materials in parts by weight: 3.5 parts shape memory polymer, 1.8 parts metal-based shape memory alloy nanoparticles, 5.5 parts dual-response composite intelligent additive, 81 parts composite base oil, 12 parts supramolecular thickener, and 3.5 parts self-healing microcapsules; The shape memory polymer is prepared from the following materials in parts by weight: 57 parts polylactic acid, 47 parts polycaprolactone, and 2.4 parts crosslinking agent; The metal-based shape memory alloy nanoparticles were prepared from the following materials in parts by weight: 99.3 parts nickel-titanium alloy target and 0.8 parts niobium; The dual-response composite smart additive is prepared from the following materials in parts by weight: 67 parts of pH-sensitive polymer microspheres and 37 parts of shear-sensitive nanosheets; The composite base oil is prepared from the following materials in parts by weight: 40 parts rapeseed oil, 60 parts polyol ester, and 0.24 parts nanocellulose whiskers; The supramolecular thickener is prepared from the following materials in parts by weight: 13 parts β-cyclodextrin, 67 parts polycaprolactone monomer and 23 parts polyethylene glycol monomer; The self-healing microcapsules are prepared from the following materials in parts by weight: 83 parts of wall material raw material and 18 parts of repair agent, wherein the wall material raw material contains polydopamine-polyethylene glycol block copolymer and the repair agent contains nano aluminum powder and silane coupling agent.

[0051] The preparation method of environmentally friendly lubricating grease includes the following steps: Step S1: Mix refined rapeseed oil and polyol esters in a certain proportion to obtain a composite base oil; Step S1 also includes the following steps: Step S11: Rapeseed oil is refined using a combination of molecular distillation and supercritical fluid extraction technology, resulting in a refined rapeseed oil with an unsaturated fatty acid content of 93.8%. Step S12: Mix the refined rapeseed oil and pentaerythritol ester at a ratio of 4:6 at 64°C until homogeneous.

[0052] Step S2: Add nano-cellulose whiskers to the composite base oil and disperse them ultrasonically; Step S2 also includes the following steps: Step S21: Weigh 0.24 parts of nanocellulose whiskers with an aspect ratio of 85 as a viscosity modifier; Step S22: Add nanocellulose whiskers to the composite base oil and ultrasonically disperse for 48 minutes to ensure uniform dispersion.

[0053] Step S3: Prepare supramolecular thickener precursor and add it to the composite base oil to react, so that it self-assembles to form nanomicelles and three-dimensional network structures; Step S3 also includes the following steps: Step S31: Mix β-cyclodextrin, polycaprolactone monomer, and polyethylene glycol monomer, add stannous octoate (0.3% of the total mass of the mixture), and react at 140°C for 6 hours to prepare a supramolecular thickener precursor. This supramolecular thickener has β-cyclodextrin as the core and is grafted with 5 polycaprolactone-polyethylene glycol block chains. Step S32: Add the supramolecular thickener precursor to the composite base oil and stir at 94°C for 3.4 hours. By adjusting the block length ratio, the molecules self-assemble to form nanomicelles with a diameter of 85 nm and construct a three-dimensional network structure.

[0054] Step S4: Prepare metal-based shape memory alloy nanoparticles and dop them, then add them to the system treated in step S3 and stir until homogeneous; Step S4 also includes the following steps: Step S41: Select a nickel-titanium alloy target with an atomic ratio of nickel to titanium of 49.8:50.2, and prepare metal-based shape memory alloy nanoparticles by magnetron sputtering. Step S42: The prepared metal-based shape memory alloy nanoparticles are doped with 0.8 atomic% niobium using a high-energy ball milling method. After treatment, the nanoparticles are added to the system treated in step S3 and stirred evenly.

[0055] Step S5: Prepare a dual-response composite smart additive and add it to the system treated in step S4, and continue stirring; Step S5 also includes the following steps: Step S51: Prepare polyacrylic acid-polyethylene glycol graft copolymer microspheres with a particle size of 240 nm as pH-sensitive polymer microspheres, and molybdenum disulfide nanosheets with a thickness of 8 nm and a sheet diameter of 380 nm as shear-sensitive nanosheets. Step S52: Mix 67 parts of pH-sensitive polymer microspheres and 37 parts of shear-sensitive nanosheets evenly to obtain a dual-response composite smart additive, and then add it to the system treated in step S4, and continue stirring for 1.7 hours.

[0056] Step S6: Dissolve the shape memory polymer and add it dropwise to the system treated in step S5 to react and form a network structure; Step S6 also includes the following steps: Step S61: Select the crosslinking product based on polylactic acid-polycaprolactone block copolymer as the shape memory polymer, with a glass transition temperature of 27℃ and a crystallinity of 37%; Step S62: Dissolve the shape memory polymer in dichloromethane at a mass ratio of 1:8, and then add it dropwise to the system treated in step S5. Stir the reaction at 44°C for 4.4 hours to allow the shape memory polymer to form a network structure in the system.

[0057] Step S7: After preparing self-healing microcapsules and determining the grafting rate, add them to the system treated in step S6 and stir evenly to obtain environmentally friendly lubricating grease.

[0058] Step S7 also includes the following steps: Step S71: Self-healing microcapsules were prepared using atom transfer radical polymerization technology. Polydopamine-polyethylene glycol block copolymer was grafted onto the surface of the microcapsule wall material. The self-healing microcapsule wall thickness was 68 nm, the rupture pressure was 130 Pa, and the mass ratio of nano-aluminum powder to silane coupling agent in the core was 4.8:1. Step S72: After the self-healing microcapsules are prepared, the grafting rate of the polydopamine-polyethylene glycol block copolymer is determined by nuclear magnetic resonance spectroscopy. The grafting rate is 27%. The copolymer is then added to the system treated in step S6 and stirred evenly to obtain an environmentally friendly lubricating grease.

[0059] Step S73: When preparing self-healing microcapsules, the reaction temperature is controlled at 54°C and maintained for 7.4 hours.

[0060] Comparative Example 1 differs from Example 1 in that no shape memory polymer was added, while the remaining steps are the same as in Example 1.

[0061] Comparative Example 2 differs from Example 1 in that it uses conventional distillation to refine rapeseed oil, the rapeseed oil has an unsaturated fatty acid content of 85%, and does not use molecular distillation-supercritical extraction combined technology. The remaining steps are the same as in Example 1.

[0062] Comparative Example 3 differs from Example 1 in that: the self-healing microcapsules were prepared by emulsification polymerization, without grafting polydopamine-polyethylene glycol block copolymers, and without using atom transfer radical polymerization technology; the remaining steps were the same as in Example 1.

[0063] Comparative Example 4 differs from Example 1 in that no dual-response composite smart additive was added, while the remaining steps are the same as in Example 1.

[0064] Performance testing: Performance tests were conducted on the environmentally friendly lubricating greases treated in Examples 1, 2, 3, 1, 2, 3, and 4. The test items and corresponding national standards are as follows: Cone penetration reflects the consistency of lubricating grease, and is determined according to GB / T269-1991 "Determination of Cone Penetration of Lubricating Greases and Petroleum Greases"; Dropping point reflects high temperature resistance, refer to GB / T4929-1985 "Determination of Dropping Point of Lubricating Grease"; Oxidation stability (pressure drop) reflects antioxidant capacity, referring to GB / T394-1983 "Determination of Oxidation Stability of Lubricating Oils"; The corrosion grade of copper strips reflects the corrosivity to metals, referring to GB / T7326-1987 "Test Method for Corrosion of Copper Strips in Lubricating Grease"; The maximum non-seize load (PB value) reflects the extreme pressure performance, referring to GB / T3142-1982 "Determination of Lubricant Load Capacity (Four-Ball Method)"; The wear scar diameter (d, mm) reflects the wear resistance, referring to GB / T3142-1982 "Determination of Lubricant Carrying Capacity (Four-Ball Method)"; Self-healing efficiency (%) reflects the ability to repair after wear, referring to industry standards (the percentage of repaired area on the worn surface after the action of grease). Biodegradability (%) reflects environmental performance, referring to GB / T19205-2003 "Determination of Biodegradability of Lubricants".

[0065] The obtained test data are recorded in Table 1 below: Conicity (0.1 mm) 285 290 280 350 310 295 320 Drop point (°C) 220 215 225 180 195 210 190 Oxidation stability (kPa) 35 38 32 65 50 40 55 Copper strip corrosion (grade) 1a 1a 1a 2b 2a 1b 2a PB value (N) 850 830 870 650 700 780 680 Abrasion scar diameter (mm) 0.45 0.47 0.43 0.68 0.60 0.52 0.65 Self-repairing efficiency (%) 85 82 88 45 70 55 65 Biodegradation rate (%) 92 90 94 88 85 90 86 Analysis of the performance test results of the embodiments and comparative examples shows that the environmentally friendly lubricating grease prepared in the embodiments of the present invention exhibits significant advantages in all performance indicators.

[0066] In terms of consistency stability, the cone penetration of the example is more moderate, indicating that its consistency control is more reasonable. This is due to the synergistic effect of the three-dimensional network structure formed by the self-assembly of the supramolecular thickener and the network constructed by the shape memory polymer, which makes the system structure stable. In contrast, Comparative Example 1 lacks shape memory polymer, and Comparative Example 2 has poor rapeseed oil refining process, resulting in a loose system structure or insufficient stability, and the consistency deviates from the ideal range.

[0067] Regarding high-temperature resistance, the dropping point of the examples was significantly higher, indicating that it could maintain lubrication performance at higher temperatures. This is closely related to the temperature response characteristics of the shape memory polymer, the heat resistance of the three-dimensional network of the supramolecular thickener, and the synergistic high-temperature resistance of refined rapeseed oil and polyol ester in the composite base oil. Comparative Example 1 lacked shape memory polymer, Comparative Example 2 had insufficient base oil refinement, and Comparative Example 4 lacked dual-response additives. The system was easily destroyed at high temperatures, and the dropping point was significantly reduced.

[0068] In the oxidation stability test, the smaller pressure drop in the example indicates stronger antioxidant capacity. This is because the high content of unsaturated fatty acids in the composite base oil after molecular distillation-supercritical extraction provides a natural antioxidant basis. At the same time, the synergistic protective effect of the dual-response additives and metal-based shape memory alloy nanoparticles effectively slows down the oxidation process. In contrast, the comparative example 2 has a simple rapeseed oil refining process, low unsaturated fatty acid content, and weak antioxidant basis. The comparative example 1 also shows a significant decrease in oxidation stability due to the lack of network protection from shape memory polymers.

[0069] Regarding metal corrosion, the embodiments exhibit a lower corrosion level and better protection of metal surfaces. This is closely related to the corrosion inhibition effect of the polydopamine-polyethylene glycol block copolymer in the self-healing microcapsule wall material and the compatibility of the various components. In contrast, Comparative Examples 1, 2, and 4 show significantly enhanced metal corrosion due to the lack of shape memory polymer encapsulation protection, higher levels of impurities in the base oil, or the absence of synergistic corrosion inhibition from dual-response additives.

[0070] In terms of extreme pressure performance and anti-wear performance, the example showed superior performance with a higher PB value, indicating stronger load-bearing capacity and smaller wear scar diameter, indicating lower wear. This is due to the synergistic effect of the shear-sensitive nanosheets in the dual-response composite smart additive enhancing lubrication under high pressure shear, the strengthening support of metal-based shape memory alloy nanoparticles, and the timely repair of micro-wear by self-healing microcapsules. In contrast, Comparative Example 4, lacking the dual-response additive, could not form an effective lubrication enhancement layer under high pressure. Comparative Example 1, lacking the network support of shape memory polymers, showed a significant decrease in both extreme pressure and anti-wear performance.

[0071] In terms of self-healing efficiency, the examples are significantly higher than the comparative examples. This is because the self-healing microcapsules are prepared using atom transfer radical polymerization technology, and the polydopamine-polyethylene glycol block copolymer grafted onto the wall material of the self-healing microcapsules can precisely control the release of the repair agent after rupture. Combined with the network reset effect of shape memory polymers, efficient repair is achieved. In contrast, the microcapsules in the comparative example three were not grafted with this block copolymer, resulting in uncontrolled release of the repair agent. The self-healing efficiency of the comparative example one was significantly reduced due to the lack of auxiliary reset by shape memory polymers.

[0072] In terms of biodegradability, the example maintained a high level, demonstrating good environmental performance. This is because the composite base oil uses renewable rapeseed oil as raw material and retains highly biocompatible components after refining. Combined with various environmentally friendly additives, it achieves efficient biodegradation. In contrast, the second example has a significantly lower degradation rate due to the simple rapeseed oil refining process and residual impurities affecting biocompatibility.

[0073] In summary, the superior performance of the embodiments stems from the synergistic effect of the components. Shape memory polymers and supramolecular thickeners construct a stable network structure, metal-based shape memory alloy nanoparticles enhance mechanical properties, dual-responsive additives dynamically regulate lubrication, refined composite base oil provides an excellent substrate, and self-healing microcapsules achieve damage repair. In contrast, the comparative examples, due to the lack of key components or process defects, showed varying degrees of performance degradation, fully demonstrating the scientific validity and rationality of the formulation design and preparation process of this invention. This indicates that the environmentally friendly lubricating grease and its preparation method provided by this invention have a broader market prospect and are more suitable for widespread application.

[0074] In the description of this specification, references to terms such as "an experiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that experiment or example is included in at least one experiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same experiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more experiments or examples.

[0075] The preferred experiments disclosed above are merely illustrative of the invention. These preferred experiments do not exhaustively describe all details, nor do they limit the invention to the specific embodiments described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these experiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize it. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. An environmentally friendly lubricating grease, characterized in that, It is composed of the following materials in parts by weight: 2.5-3.5 parts of shape memory polymer, 1.2-1.8 parts of metal-based shape memory alloy nanoparticles, 3.5-5.5 parts of dual-response composite intelligent additive, 76-81 parts of composite base oil, 11-12 parts of supramolecular thickener and 2.5-3.5 parts of self-healing microcapsules; The shape memory polymer is prepared from the following materials in parts by weight: 53-57 parts polylactic acid, 43-47 parts polycaprolactone, and 1.6-2.4 parts crosslinking agent; The metal-based shape memory alloy nanoparticles are prepared from the following materials in parts by weight: 99.2-99.3 parts of nickel-titanium alloy target and 0.7-0.8 parts of niobium; The dual-response composite smart additive is prepared from the following materials in parts by weight: 63-67 parts of pH-sensitive polymer microspheres and 33-37 parts of shear-sensitive nanosheets; The composite base oil is prepared from the following materials in parts by weight: 40 parts rapeseed oil, 60 parts polyol ester, and 0.16-0.24 parts nanocellulose whiskers; The supramolecular thickener is prepared from the following materials in parts by weight: 12-13 parts of β-cyclodextrin, 63-67 parts of polycaprolactone monomer and 22-23 parts of polyethylene glycol monomer; The self-healing microcapsule is prepared from the following materials in parts by weight: 82-83 parts of wall material raw material and 17-18 parts of repair agent, wherein the wall material raw material contains polydopamine-polyethylene glycol block copolymer and the repair agent contains nano-aluminum powder and silane coupling agent.

2. A method for preparing an environmentally friendly lubricating grease, applicable to the environmentally friendly lubricating grease described in claim 1, characterized in that, The preparation method of environmentally friendly lubricating grease includes the following steps: Step S1: Mix refined rapeseed oil and polyol esters in a certain proportion to obtain a composite base oil; Step S2: Add nano-cellulose whiskers to the composite base oil and disperse them ultrasonically; Step S3: Prepare supramolecular thickener precursor and add it to the composite base oil to react, so that it self-assembles to form nanomicelles and three-dimensional network structures; Step S4: Prepare metal-based shape memory alloy nanoparticles and dop them, then add them to the system treated in step S3 and stir until homogeneous; Step S5: Prepare a dual-response composite smart additive and add it to the system treated in step S4, and continue stirring; Step S6: Dissolve the shape memory polymer and add it dropwise to the system treated in step S5 to react and form a network structure; Step S7: After preparing self-healing microcapsules and determining the grafting rate, add them to the system treated in step S5 and stir evenly to obtain environmentally friendly lubricating grease.

3. The method for preparing an environmentally friendly lubricating grease according to claim 2, characterized in that, Step S1 also includes the following steps: Step S11: The rapeseed oil is refined using a combination of molecular distillation and supercritical fluid extraction to achieve an unsaturated fatty acid content of 93.2%–93.8% in the refined rapeseed oil. Step S12: Mix the refined rapeseed oil and pentaerythritol ester at a ratio of 4:6 at 56-64°C until homogeneous.

4. The method for preparing an environmentally friendly lubricating grease according to claim 2, characterized in that, Step S2 also includes the following steps: Step S21: Weigh 0.16 to 0.24 parts of nanocellulose whiskers with an aspect ratio of 65 to 85 as a viscosity modifier; Step S22: Add nanocellulose whiskers to the composite base oil and ultrasonically disperse for 42-48 minutes to ensure uniform dispersion.

5. The method for preparing an environmentally friendly lubricating grease according to claim 2, characterized in that, Step S3 also includes the following steps: Step S31: Mix β-cyclodextrin, polycaprolactone monomer, and polyethylene glycol monomer, add stannous octoate (0.1%–0.3% of the total mass of the mixture), and react at 120–140°C for 4–6 hours to prepare a supramolecular thickener precursor. This supramolecular thickener has β-cyclodextrin as the core and is grafted with 5 polycaprolactone-polyethylene glycol block chains. Step S32: Add the supramolecular thickener precursor to the composite base oil and stir the reaction at 86-94°C for 2.6-3.4 hours. By adjusting the block length ratio, the molecules self-assemble to form nanomicelles with a diameter of 65-85 nm and construct a three-dimensional network structure.

6. The method for preparing an environmentally friendly lubricating grease according to claim 2, characterized in that, Step S4 also includes the following steps: Step S41: Select a nickel-titanium alloy target with an atomic ratio of nickel to titanium of 49.2:50.8 to 49.8:50.2, and prepare metal-based shape memory alloy nanoparticles by magnetron sputtering. Step S42: The prepared metal-based shape memory alloy nanoparticles are doped with 0.7-0.8 atomic% niobium using a high-energy ball milling method. After treatment, the nanoparticles are added to the system treated in step S3 and stirred evenly.

7. The method for preparing an environmentally friendly lubricating grease according to claim 2, characterized in that, Step S5 also includes the following steps: Step S51: Prepare polyacrylic acid-polyethylene glycol graft copolymer microspheres with a particle size of 160-240 nm as pH-sensitive polymer microspheres, and molybdenum disulfide nanosheets with a thickness of 7-8 nm and a sheet diameter of 220-380 nm as shear-sensitive nanosheets. Step S52: Mix 63-67 parts of pH-sensitive polymer microspheres with 33-37 parts of shear-sensitive nanosheets to obtain a dual-response composite smart additive, and then add it to the system treated in step S4, and continue stirring for 1.3-1.7 hours.

8. The method for preparing an environmentally friendly lubricating grease according to claim 2, characterized in that, Step S6 also includes the following steps: Step S61: Select a crosslinking product based on polylactic acid-polycaprolactone block copolymer as the shape memory polymer, with a glass transition temperature of 23-27℃ and a crystallinity of 33%-37%; Step S62: Dissolve the shape memory polymer in dichloromethane at a mass ratio of 1:5 to 1:8, and then add it dropwise to the system treated in step S5. Stir the reaction at 36 to 44°C for 3.6 to 4.4 hours to allow the shape memory polymer to form a network structure in the system.

9. The method for preparing an environmentally friendly lubricating grease according to claim 2, characterized in that, Step S7 also includes the following steps: Step S71: Self-healing microcapsules were prepared using atom transfer radical polymerization technology. Polydopamine-polyethylene glycol block copolymer was grafted onto the surface of the microcapsule wall material. The self-healing microcapsule wall thickness was 62-68 nm, the rupture pressure was 120-130 Pa, and the mass ratio of nano-aluminum powder to silane coupling agent in the core was 4.2:1-4.8:

1. Step S72: After the self-healing microcapsules are prepared, the grafting rate of the polydopamine-polyethylene glycol block copolymer is determined by nuclear magnetic resonance spectroscopy. The grafting rate is set to 23% to 27%. The copolymer is then added to the system treated in step S6 and stirred until homogeneous to obtain an environmentally friendly lubricating grease.

10. The method for preparing an environmentally friendly lubricating grease according to claim 2, characterized in that, Step S7 also includes the following steps: Step S73: When preparing self-healing microcapsules, control the reaction temperature at 46-54°C and maintain the reaction temperature for 6.6-7.4 hours.