Low-ash-content low-sulfur vehicle lubricating oil and preparation method thereof

Abstract

The invention provides low-ash low-sulfur vehicle lubricating oil and a preparation method thereof, and belongs to the technical field of lubricating oil. According to the invention, an amphiphilic molecular structure is generated through modified polyisobutylene succinic anhydride and polyamidoamine, a supramolecular ordered film is formed through self-assembly, combustion products and carbon deposition particles are captured, and ash content and sediment generation are reduced, so that the performance requirements of low-ash-content and low-sulfur lubricating oil are met; the reversible reaction of N-(2-aminoethyl) maleimide and 2, 5-bis (aminomethyl) furan is adopted to endow molecular broken bond-recombination self-repairing capability, and micro cracks of a lubricating system are repaired; for the anti-wear agent, UV / O3 is adopted to activate MXene, and multi-step modification of tributyl borate and fluoroalkyl silane is combined, so that the lubricating oil is endowed with low friction coefficient, high thermal stability and excellent dispersing performance, lasting lubrication and effective protection are provided under high-temperature and high-pressure conditions, and lasting lubrication protection under extreme working conditions is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of lubricating oils and relates to a low-ash and low-sulfur automotive lubricating oil and a preparation method thereof. Background Art

[0002] Against the backdrop of today's rapidly developing automotive industry, the quality and performance of lubricants are receiving increasing attention. As a critical medium for the proper operation of engines, lubricants not only reduce friction and wear but are also directly linked to engine efficiency, durability, and environmental performance. As global environmental protection requirements continue to increase, the formulation and composition of automotive lubricants are also evolving, particularly in the area of ​​reducing ash and sulfur content, which has become a key research area within the industry.

[0003] Traditional automotive lubricants are typically mineral oil-based, with a variety of additives added to enhance their anti-wear, friction-reducing, and cleanliness properties. These additives, which range from antioxidants to detergents and extreme pressure agents, are designed to improve the lubricant's overall performance. However, these traditional additives often lead to the formation of high ash content during lubricant use. Ash is the solid residue produced by the combustion or oxidation process of the lubricant. Over time, the accumulation of ash not only affects the lubricant's cleanliness but can also lead to the formation of carbon deposits and sediments within the engine, compromising engine performance and life. The presence of such carbon deposits can lead to reduced engine power, reduced fuel efficiency, and even serious mechanical failure.

[0004] Furthermore, many conventional lubricants contain high levels of sulfur. Oxidation of sulfur, particularly in high-temperature environments, can lead to corrosion and deposit formation, reducing the efficiency and safety of the lubricant. The sulfur oxides produced by the combustion of high-sulfur lubricants not only pollute the environment but can also corrode engine components, shortening their service life.

[0005] In recent years, synthetic PAO and other base oils have gained popularity due to their superior temperature stability and low volatility. These synthetic base oils exhibit improved oxidation resistance and thermal stability at high temperatures, which can significantly improve lubricant performance. However, even with synthetic base oils, existing technologies still face the challenge of further reducing ash and sulfur contents. Summary of the Invention

[0006] To address the above issues, the present invention aims to provide a low-ash, low-sulfur automotive lubricant and its preparation method. The present invention employs a modified polyisobutylene succinic anhydride amphiphilic molecule to form a supramolecular ordered film on the metal surface, reducing friction and wear while capturing combustion products and carbon deposits, meeting the demand for low-ash, low-sulfur lubricants and extending engine life. The introduction of polyamidoamine and multi-step chemical modification enhances the molecule's polarity, dispersibility, and detergency, enabling efficient capture of acidic and polar impurities and preventing deposit formation. The reaction of N-(2-aminoethyl)maleimide with 2,5-bis(aminomethyl)furan imparts the molecule with a "bond-breaking-recombination" self-healing capability, repairing microcracks in the lubrication system. UV / O3 activation and tributyl borate modification of the MXene material surface reduce friction and enhance thermal stability. Fluorination of fluoroalkylsilanes introduces long-chain fluorine groups, giving the material extremely low surface energy, excellent high-temperature resistance, and good lubricant dispersion stability, enabling long-lasting lubrication protection under extreme operating conditions.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a method for preparing a low-ash, low-sulfur automotive lubricant oil, the method comprising:

[0009] S1: Dispersing polyisobutylene succinic anhydride in toluene, stirring and dispersing, and then adding polyamidoamine to react to obtain a primary amphiphilic polymer backbone;

[0010] S2: After reacting the primary amphiphilic polymer skeleton with N-(2-aminoethyl)maleimide, 2,5-bis(aminomethyl)furan was added to react, the temperature was lowered to obtain a reaction solution G, and p-methylbenzaldehyde was added to react to obtain a biomimetic supramolecular self-assembled detergent;

[0011] S3: Treating Ti3C2TxMXene powder with a UV / O3 processor to obtain pre-treated powder; reacting the pre-treated powder with tributyl borate to obtain partially boronated MXene powder;

[0012] S4: reacting partially boronized MXene powder with fluoroalkylsilane 1H,1H,2H,2H-perfluorodecyltriethoxysilane to obtain a modified MXene-based anti-wear and friction reducer;

[0013] S5: The biomimetic supramolecular self-assembly detergent and the modified MXene-based anti-wear and friction reducer are dispersed in the synthetic PAO, and an antioxidant and a defoaming agent are added and mixed evenly to obtain a low-ash and low-sulfur automotive lubricant.

[0014] Specifically, S1: dispersing polyisobutylene succinic anhydride in toluene, stirring at a constant temperature to obtain a dispersion A, adding dropwise a toluene solution of polyamidoamine to obtain a reaction solution B, continuing to stir the reaction, and then vacuum rotary evaporation to obtain a primary amphiphilic polymer skeleton;

[0015] S2: Dispersing the primary amphiphilic polymer skeleton in anhydrous xylene, stirring at a constant temperature to obtain dispersion C, adding dropwise a xylene solution of N-(2-aminoethyl)maleimide to obtain a reaction solution D, stirring for reaction, and then heating to obtain a reaction solution E, adding dropwise a toluene solution of 2,5-bis(aminomethyl)furan to obtain a reaction solution F, stirring for reaction, and then cooling to obtain a reaction solution G, adding p-methylbenzaldehyde and continuing to stir for reaction, rotary evaporation, and drying to obtain a biomimetic supramolecular self-assembly detergent;

[0016] S3: Ti3C2TxMXene powder is treated with a UV / O3 processor to obtain a pre-treated powder; a toluene dispersion of the pre-treated powder with a mass fraction of 1-3 wt.% is prepared, a toluene solution of tributyl borate is added to obtain a reaction solution H, and the mixture is stirred at a constant temperature under sulfuric acid catalysis, centrifuged, washed, and dried to obtain a partially boronized MXene powder;

[0017] S4: dispersing partially boronated MXene powder and fluoroalkylsilane 1H,1H,2H,2H-perfluorodecyltriethoxysilane in a toluene / water solution to obtain a reaction solution I, reacting at a constant temperature, filtering, washing, and drying to obtain a modified MXene-based anti-wear and friction reducer;

[0018] S5: The biomimetic supramolecular self-assembly detergent and the modified MXene-based anti-wear and friction reducer are dispersed in the synthetic PAO, and an antioxidant and a defoaming agent are added and mixed evenly to obtain a low-ash and low-sulfur automotive lubricant.

[0019] As a preferred technical solution of the present invention, in step S1, the mass fraction of the polyisobutylene succinic anhydride dispersed in toluene is 20-30wt.%, for example, it can be 20wt.%, 21wt.%, 22wt.%, 23wt.%, 24wt.%, 25wt.%, 26wt.%, 27wt.%, 28wt.%, 29wt.% or 30wt.%, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0020] In some optional embodiments, the polyisobutylene succinic anhydride is dispersed in toluene and stirred at a constant temperature of 120-130°C to obtain dispersion A, for example, it can be 120°C, 121°C, 122°C, 123°C, 124°C, 125°C, 126°C, 127°C, 128°C, 129°C or 130°C, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0021] In some optional embodiments, the mass fraction of the toluene solution of the polyamide amine is 10-20 wt.%, for example, it can be 10 wt.%, 11 wt.%, 12 wt.%, 13 wt.%, 14 wt.%, 15 wt.%, 16 wt.%, 17 wt.%, 18 wt.%, 19 wt.% or 20 wt.%, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0022] In some optional embodiments, the molar ratio of the polyisobutylene succinic anhydride to the polyamidoamine is 1:(0.3-0.6), for example, it can be 1:0.3, 1:0.33, 1:0.36, 1:0.39, 1:0.42, 1:0.45, 1:0.48, 1:0.51, 1:0.54 or 1:0.6, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0023] In some optional embodiments, the reaction liquid B is stirred for 4-5 hours, for example, 4 hours, 4.1 hours, 4.2 hours, 4.3 hours, 4.4 hours, 4.5 hours, 4.6 hours, 4.7 hours, 4.8 hours, 4.9 hours or 5 hours, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0024] As a preferred technical solution of the present invention, in step S2, the mass fraction of the primary amphiphilic polymer skeleton dispersed in anhydrous xylene is 15-25wt.%, for example, it can be 15wt.%, 16wt.%, 17wt.%, 18wt.%, 19wt.%, 20wt.%, 21wt.%, 22wt.%, 23wt.%, 24wt.% or 25wt.%, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0025] In some optional embodiments, the primary amphiphilic polymer backbone is dispersed in anhydrous xylene and stirred at a constant temperature of 80-90°C to obtain a dispersion C, for example, 80°C, 81°C, 82°C, 83°C, 84°C, 85°C, 86°C, 87°C, 88°C, 89°C or 90°C, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0026] In some optional embodiments, the mass fraction of the xylene solution of N-(2-aminoethyl)maleimide is 10-15 wt.%, for example, it can be 10 wt.%, 10.5 wt.%, 11 wt.%, 11.5 wt.%, 12 wt.%, 12.5 wt.%, 13 wt.%, 13.5 wt.%, 14 wt.%, 14.5 wt.% or 15 wt.%, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0027] In some optional embodiments, the molar ratio of the primary amphiphilic polymer backbone to N-(2-aminoethyl)maleimide is 1:(0.1-0.2), for example, it can be 1:0.1, 1:0.11, 1:0.12, 1:0.13, 1:0.14, 1:0.15, 1:0.16, 1:0.17, 1:0.18, 1:0.19 or 1:0.2, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] In some optional embodiments, the stirring reaction time of the reaction liquid D is 1-2h, for example, it can be 1h, 1.1h, 1.2h, 1.3h, 1.4h, 1.5h, 1.6h, 1.7h, 1.8h, 1.9h or 2h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0029] In some optional embodiments, the reaction liquid D is stirred and then heated to 110-120°C to obtain reaction liquid E, for example, it can be 110°C, 111°C, 112°C, 113°C, 114°C, 115°C, 116°C, 117°C, 118°C, 119°C or 120°C, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] In some optional embodiments, the mass fraction of the toluene solution of 2,5-bis(aminomethyl)furan is 5-10wt.%, for example, it can be 5wt.%, 5.5wt.%, 6wt.%, 6.5wt.%, 7wt.%, 7.5wt.%, 8wt.%, 8.5wt.%, 9wt.%, 9.5wt.% or 10wt.%, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0031] In some optional embodiments, the molar ratio of N-(2-aminoethyl)maleimide to 2,5-bis(aminomethyl)furan is 1:(1-1.2), for example, it can be 1:1, 1:1.02, 1:1.04, 1:1.06, 1:1.08, 1:1.1, 1:1.12, 1:1.14, 1:1.16, 1:1.18 or 1:1.2, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] In some optional embodiments, the stirring reaction time of the reaction liquid F is 2-3h, for example, it can be 2h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h or 3h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0033] In some optional embodiments, the reaction liquid F is stirred and then cooled to 60-70°C to obtain reaction liquid G, for example, it can be 60°C, 61°C, 62°C, 63°C, 64°C, 65°C, 66°C, 67°C, 68°C, 69°C or 70°C, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0034] In some optional embodiments, the feeding amount of the p-methylbenzaldehyde is 5-10% of the mass of the primary amphiphilic polymer backbone, for example, it can be 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5% or 10%, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0035] In some optional embodiments, after adding p-methylbenzaldehyde to the reaction liquid G, the stirring reaction is continued for 1-2 hours, for example, it can be 1 hour, 1.1 hours, 1.2 hours, 1.3 hours, 1.4 hours, 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours or 2 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] As a preferred technical solution of the present invention, in step S3, the ozone concentration of the Ti3C2TxMXene powder when treated with a UV / O3 processor is 50-100 ppm, for example, it can be 50 ppm, 55 ppm, 60 ppm, 65 ppm, 70 ppm, 75 ppm, 80 ppm, 85 ppm, 90 ppm, 95 ppm or 100 ppm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] In some optional embodiments, the Ti3C2TxMXene powder is treated with a UV / O3 processor for 30-50 min, for example, 30 min, 32 min, 34 min, 36 min, 38 min, 40 min, 42 min, 44 min, 46 min, 48 min or 50 min, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] In some optional embodiments, the mass fraction of the toluene dispersion of the pre-treated powder is 1-3 wt.%, for example, it can be 1 wt.%, 1.2 wt.%, 1.4 wt.%, 1.6 wt.%, 1.8 wt.%, 2 wt.%, 2.2 wt.%, 2.4 wt.%, 2.6 wt.%, 2.8 wt.% or 3 wt.%, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0039] In some optional embodiments, the mass fraction of the toluene solution of tributyl borate is 5-10wt.%, for example, it can be 5wt.%, 5.5wt.%, 6wt.%, 6.5wt.%, 7wt.%, 7.5wt.%, 8wt.%, 8.5wt.%, 9wt.%, 9.5wt.% or 10wt.%, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0040] In some optional embodiments, the mass ratio of the pre-treated powder to tributyl borate is 1:(2-4), for example, it can be 1:2, 1:2.2, 1:2.4, 1:2.6, 1:2.8, 1:3, 1:3.2, 1:3.4, 1:3.6, 1:3.8 or 1:4, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0041] In some optional embodiments, the temperature of the constant temperature reaction of the reaction liquid H is 60-80°C, for example, it can be 60°C, 62°C, 64°C, 66°C, 68°C, 70°C, 72°C, 74°C, 76°C, 78°C or 80°C, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0042] In some optional embodiments, the constant temperature reaction time of the reaction liquid H is 3-4h, for example, it can be 3h, 3.1h, 3.2h, 3.3h, 3.4h, 3.5h, 3.6h, 3.7h, 3.8h, 3.9h or 4h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0043] As a preferred technical solution of the present invention, in step S4, the mass ratio of the partially boronated MXene powder to the fluoroalkylsilane is 1:(0.8-1.2), for example, it can be 1:0.8, 1:0.84, 1:0.88, 1:0.92, 1:0.96, 1:1, 1:1.04, 1:1.08, 1:1.12, 1:1.16 or 1:1.2, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0044] In some optional embodiments, the mass fraction of the partially boronated MXene powder in the toluene / water solution is 0.8-1.2 wt.%, for example, it can be 0.8 wt.%, 0.84 wt.%, 0.88 wt.%, 0.92 wt.%, 0.96 wt.%, 1 wt.%, 1.04 wt.%, 1.08 wt.%, 1.12 wt.%, 1.16 wt.% or 1.2 wt.%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0045] In some optional embodiments, the temperature of the constant temperature reaction of the reaction liquid I is 80-100°C, for example, it can be 80°C, 82°C, 84°C, 86°C, 88°C, 90°C, 92°C, 94°C, 96°C, 98°C or 100°C, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0046] In some optional embodiments, the constant temperature reaction time of the reaction solution I is 2-3 hours, for example, it can be 2 hours, 2.1 hours, 2.2 hours, 2.3 hours, 2.4 hours, 2.5 hours, 2.6 hours, 2.7 hours, 2.8 hours, 2.9 hours or 3 hours, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0047] As a preferred technical solution of the present invention, in step S5, the feeding amount of the antioxidant is 0.1-0.5% of the mass of the synthesized PAO, for example, it can be 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45% or 0.5%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0048] The antioxidant is any one of alkylated diphenylamine and IRGANOXL135 or a combination of the two;

[0049] In some optional embodiments, the defoaming agent is SAG47, and the amount of the defoaming agent is 0.01-0.05% of the mass of the synthetic PAO, for example, it can be 0.01%, 0.015%, 0.02%, 0.025%, 0.03%, 0.035%, 0.04%, 0.045% or 0.05%, but is not limited to the listed values, and other unlisted values ​​within this numerical range are also applicable.

[0050] In a second aspect, the present invention provides a low-ash, low-sulfur automotive lubricant. The low-ash, low-sulfur automotive lubricant comprises a synthetic PAO, a biomimetic supramolecular self-assembly detergent, and a modified MXene-based anti-wear and friction reducer, wherein the mass ratio of the synthetic PAO, biomimetic supramolecular self-assembly detergent, and modified MXene-based anti-wear and friction reducer is 100:(3-5):(0.3-0.8).

[0051] Inspired by the structure and functional properties of biological and cell membranes, this invention leverages their bilayer structure and self-assembly mechanism to construct a stable supramolecular ordered film through the spontaneous arrangement of head-to-tail amphiphilic molecules on metal surfaces or oil-interfaces. The formation of this ordered film not only effectively reduces friction and wear at the metal interface but also enhances the ability to capture combustion products, carbon deposits, and acidic impurities, thereby significantly improving the overall performance of the lubricant. To achieve this goal, the present invention uses polyisobutylene succinic anhydride as the base raw material, combining its unique molecular structure with chemical modification to regulate its functionality.

[0052] Polyisobutylene succinic anhydride (PISA) is a molecule with significant amphiphilic properties. Its hydrophobic polyisobutylene segments are long-chain hydrocarbon structures, endowing it with excellent lubricity. The hydrophilic anhydride groups, on the other hand, serve as active sites, amenable to further chemical modification. However, PISA also has limitations: its strong hydrophobicity makes it difficult to achieve stable dispersion in lubricants. Especially under high-temperature and high-pressure conditions, PISA alone is ineffective in removing carbon deposits and acidic combustion products generated in engine lubrication systems, limiting the lubricant's detergency and antioxidant properties.

[0053] To overcome this problem, the present invention introduces polyamidoamine as a modifier. Polyamidoamine's molecular structure contains multiple primary and secondary amino groups, which are highly nucleophilic and capable of undergoing a ring-opening reaction with the anhydride groups of polyisobutylene succinic anhydride. During the reaction, the anhydride groups open to form amide bonds and carboxylate or ester bonds. This chemical reaction not only imparts greater chemical stability to the molecule but also creates a modified molecule with amphiphilic properties. Its molecular structure retains the hydrophobic polyisobutylene segments while also incorporating hydrophilic amide and carboxylic acid groups, giving the molecule significant amphiphilic properties.

[0054] The introduction of polyamidoamine optimizes the performance of polyisobutylene succinic anhydride. First, the hydrophobic, long-chain polyisobutylene moiety continues to provide its inherent lubricating properties, enabling the modified molecule to form a low-friction molecular film at the metal interface, significantly reducing the coefficient of friction and wear rate. Second, the newly generated amide and carboxylic acid groups significantly increase the polarity of the molecule, enabling more uniform dispersion within the lubricant matrix and preventing molecular aggregation or precipitation. Furthermore, the modified amphiphilic molecular structure forms a stable molecular self-assembly system within the lubricant, effectively capturing acidic and polar products generated during engine combustion, thereby preventing these combustion products from depositing on metal surfaces.

[0055] Notably, the amphiphilic molecular structure also plays a significant role in cleaning the combustion environment. By capturing acidic and polar combustion products, the modified molecules can reduce ash formation in lubricating oils while preventing the accumulation and deposition of carbon particles. The amino-modified polyisobutylene succinic anhydride system employed in this invention produces minimal inorganic residue in high-temperature combustion products, thus achieving "low ash content." Furthermore, the system enhances alkali storage capacity through intermolecular hydrogen bonding, π-π stacking, and polar interactions.

[0056] Although primary amphiphilic polymer backbones already possess considerable detergency in lubricating oils, their intermolecular interactions are weak, relying primarily on simple physical adsorption between polar groups and combustion products, making them difficult to form stable bonds with complex combustion products. In particular, impurities generated during engine combustion are numerous and complex, making efficient capture and dispersion difficult with a primary amphiphilic polymer backbone alone. Therefore, to further enhance the performance of detergents, the present invention introduces a series of functional molecules for gradual modification, enhancing their intermolecular interactions and their ability to capture combustion products.

[0057] First, the present invention introduces N-(2-aminoethyl)maleimide for chemical modification. The molecular structure of N-(2-aminoethyl)maleimide contains a primary amino group and a five-membered ring imide group, wherein the amino group has a strong nucleophilicity and can combine with the carboxylic acid group or residual anhydride group in the primary amphiphilic polymer skeleton through an amidation reaction. This reaction not only generates a chemically stable amide bond, but also introduces a maleimide structure into the molecule. As a highly polar structural unit, maleimide can significantly enhance the polarity of the molecule, thereby improving the ability to capture polar impurities in combustion products. In addition, the rigid structure of maleimide helps to improve the orderliness of the arrangement between molecules, thereby further optimizing its dispersibility and stability in lubricating oils.

[0058] Next, the present invention further improves the cleaning performance of the primary amphiphilic polymer skeleton by introducing the functional modified molecule 2,5-bis(aminomethyl)furan. The 2,5-bis(aminomethyl)furan molecule contains two reactive amine groups, which can undergo amidation reaction with the remaining carboxylic acid groups in the amphiphilic polymer skeleton to form more amide bonds. At the same time, the furan group is introduced into the molecular structure, giving the detergent molecule stronger functionality. Due to its conjugated structure, the furan ring has a rich π electron cloud distribution. This property enables it to form a stable interaction with aromatic compounds or other conjugated molecules in the combustion products through π-π stacking. The π-π interaction not only enhances the detergent's ability to capture combustion products, but also improves its intermolecular interaction force in the lubricating oil, enabling the detergent to more effectively disperse the combustion products and prevent them from depositing on the metal surface.

[0059] Furthermore, in the multi-step chemical modification of the detergent, the present invention utilizes N-(2-aminoethyl)maleimide and 2,5-bis(aminomethyl)furan through a Diels-Alder reversible reaction, enabling the molecules to undergo a bond breaking and recombination process within a certain temperature range, thereby forming a partially reversible cross-linked network. When microcracks or localized wear develop in the lubricating oil system during operation, heating or application of external energy to trigger the reverse Diels-Alder reaction can cause the cross-links to break and then regenerate into DA adducts upon subsequent cooling or re-coordination, repairing or healing the microcracks. Furthermore, the DA bond between the furan ring and the maleimide can also increase the compatibility and toughness of the composite film when in contact with the external friction interface, further enhancing the lubricant's ability to protect the friction pair surface, extending its service life and reducing high-temperature deposits.

[0060] To further enhance the electronic properties and intermolecular interactions of the detergent, the present invention also introduces p-methylbenzaldehyde for functional modification. The aldehyde group in the p-methylbenzaldehyde molecule can undergo a Schiff base reaction with the residual amino group in the detergent molecule to form a polar and rigid imine bond. The imine bond is not only structurally stable but also has a high electron cloud density, which enables it to effectively adsorb polar or charged particles in the combustion products. In addition, the presence of the imine bond further strengthens the interaction between molecules and improves the overall three-dimensional stability of the molecule. The methyl substituent of p-methylbenzaldehyde also imparts a certain hydrophobicity to the molecule. The combination of this local hydrophobicity and the amphiphilic structure enables the detergent to better adapt to the hydrophobic environment of the lubricating oil, thereby achieving uniform dispersion.

[0061] Through these multi-step modification steps, the resulting detergent molecules not only possess stronger intermolecular forces but also spontaneously form a stable supramolecular network structure within the lubricant. This supramolecular network synergistically captures combustion products, carbon particles, and acidic impurities through intermolecular hydrogen bonding, π-π stacking, and electrostatic interactions, effectively preventing combustion product deposition on metal surfaces. Furthermore, the π electron cloud characteristics of the furan ring and the polarity of the Schiff base structure further enhance the detergent's adsorption capacity for combustion products. Through these synergistic effects, the modified detergent significantly improves lubricant detergency, reduces ash formation, and extends engine life.

[0062] The present invention introduces Ti3C2TxMXene powder as the core component of a lubricant anti-wear and friction reducer. Its performance is optimized through multi-step modification, overcoming the practical limitations of the original material. MXene, a two-dimensional metal carbide with a high specific surface area, excellent electrical conductivity, and rich surface chemical activity, contains a large number of active sites such as hydroxyl groups, fluorine groups, and oxides on its surface. However, these active sites easily cause particle agglomeration in the lubricant matrix, resulting in poor dispersion stability. Furthermore, MXene's anti-wear and friction-reducing properties are insufficient under high temperature and high pressure conditions.

[0063] To improve its dispersibility and lubricity, the present invention first activates the MXene powder surface through UV / O3 treatment. The synergistic effect of UV light and ozone oxidizes the hydroxyl and fluorine groups on the MXene surface, generating more active sites while removing some weakly bound surface groups and stabilizing the MXene's surface chemical structure. The activated MXene exhibits increased chemical reactivity, providing an ideal reaction platform for subsequent functionalization. This also improves its dispersibility in lubricants and prevents particle agglomeration.

[0064] On the basis of surface activation, the present invention further introduces tributyl borate to boronate MXene to significantly improve its anti-wear properties. The boron element in tributyl borate undergoes an esterification reaction with the hydroxyl groups on the surface of MXene to form a stable boron-oxygen bond. This boron oxide structure has the characteristics of a low friction coefficient and can form a lubricating film on the surface of the metal friction pair, thereby effectively reducing the friction coefficient and reducing mechanical wear. In addition, the boronation modification further stabilizes the surface chemical structure of MXene, enhances its thermal stability under high temperature and high shear conditions, and avoids degradation or failure of the material under extreme working conditions. The surface of the MXene after boronization is smoother, its compatibility with the lubricating oil matrix is ​​improved, and it exhibits better dispersion stability, laying the foundation for its efficient application in lubricating oil.

[0065] Although boronization modification significantly improves the anti-wear properties of MXene, its interfacial lubrication ability may still be insufficient under extremely high temperature or extreme pressure conditions. Therefore, the present invention further uses 1H,1H,2H,2H-perfluorodecyltriethoxysilane to fluorinate the boronized MXene. Fluoroalkylsilane combines with the hydroxyl group or boron-oxygen bond on the surface of MXene through a hydrolysis condensation reaction to generate a silicon-oxygen bond, while introducing a long-chain fluoroalkyl group on the surface of the material. Fluoroalkyl groups have extremely low surface energy and excellent chemical stability. Their introduction not only significantly reduces the friction coefficient of MXene, but also enhances its high temperature resistance, enabling it to maintain stable lubrication ability under extreme working conditions. In addition, the hydrophobicity of the fluoroalkyl group further improves the dispersibility of MXene in the lubricating oil matrix, ensuring its long-term stability in the lubricating oil.

[0066] The present invention also exhibits a synergistic enhancement effect. The biomimetic supramolecular self-assembly detergent captures acidic impurities and carbon particles in combustion products, significantly reducing deposits and ash in the lubricant. The modified MXene-based anti-wear and friction reducer forms a stable lubricating film on the friction pair surface, reducing the friction coefficient and wear rate, thereby protecting the metal surface from mechanical damage. The combination of these two functions creates a synergistic cleaning and anti-wear mechanism, improving overall engine efficiency.

[0067] Secondly, the detergent's amphiphilic molecular structure enables uniform dispersion within the lubricant matrix and forms an adsorption layer on the surface of combustion product particles. This adsorption layer not only captures carbon deposits but also prevents their aggregation. The surface functionalization of the modified MXene anti-wear agent enhances its compatibility with the lubricant and further strengthens the dispersion stability of the lubricant's components. The combination of these two ensures the long-term stability of the lubricant under high-temperature and high-pressure conditions, preventing the interaction of ash, sediment, and friction particles that could lead to lubricant failure.

[0068] Boronation with tributyl borate introduces boron-oxygen bonds onto the MXene surface. These bonds have a low friction coefficient, significantly reducing mechanical wear on the friction surface while also improving the thermal stability of the MXene. Fluorination with fluoroalkylsilane further reduces the surface energy of the MXene, improving its friction-reducing properties under high temperature and extreme pressure conditions while enhancing the material's hydrophobicity and dispersibility in lubricants. The boronization layer provides basic anti-wear properties, while the fluorination layer provides additional friction-reducing protection under extreme operating conditions. These two modification methods work synergistically, enabling the MXene material to exhibit superior anti-wear and friction-reducing properties under diverse operating conditions.

[0069] Compared with the prior art, the present invention has the following beneficial effects:

[0070] Drawing on the self-assembly mechanism of biofilms, this invention designs amphiphilic molecules by modifying polyisobutylene succinic anhydride. This creates a supramolecularly ordered film on metal surfaces, reducing friction and wear while simultaneously capturing combustion products and carbon deposits. Polyamidoamine is introduced to chemically modify polyisobutylene succinic anhydride, creating a molecular structure with significant amphiphilicity, enhancing its dispersibility and detergency. The modified molecules effectively capture acidic and polar combustion products through self-assembly, reducing ash and carbon deposits, thereby meeting the performance requirements of low-ash, low-sulfur lubricants and extending engine life.

[0071] This invention uses multi-step chemical modification of the detergent, utilizing N-(2-aminoethyl)maleimide, 2,5-bis(aminomethyl)furan, and p-tolualdehyde to enhance the molecular polarity, π-π interactions, and electronic properties, while also improving dispersibility and stability. The modified detergent self-assembles to form a supramolecular network structure, effectively capturing combustion products and acidic impurities, preventing deposit formation, significantly improving the detergency of the lubricant, reducing ash generation, and extending engine life.

[0072] The present invention also utilizes N-(2-aminoethyl)maleimide and 2,5-bis(aminomethyl)furan to undergo a reversible Diels-Alder reaction, enabling the molecules to undergo bond breaking and recombination within a certain temperature range, thereby forming a partially reversible crosslinked network. When microcracks or localized wear develop in the lubricating oil system during operation, heating or application of external energy triggers the reverse Diels-Alder reaction, breaking the crosslinks and subsequently regenerating DA adducts upon cooling or re-coordination, repairing or healing the microcracks.

[0073] The present invention uses UV / O3 treatment to activate the MXene surface, generating more active sites and improving its dispersibility. Tributyl borate is then introduced to form boron-oxygen bonds through an esterification reaction, significantly reducing the friction coefficient and enhancing thermal stability. To further enhance its lubrication capabilities under extreme operating conditions, fluorination modification with fluoroalkylsilanes is performed to form silicon-oxygen bonds and introduce long-chain fluoroalkyl groups. This imparts the MXene with extremely low surface energy and excellent high-temperature resistance, while also enhancing its hydrophobicity and dispersion stability in lubricating oils, ensuring long-lasting lubrication protection under high-temperature and high-pressure conditions. DETAILED DESCRIPTION

[0074] The technical solutions of the present invention are described in detail below with reference to specific embodiments. The embodiments described herein are specific embodiments of the present invention and are used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary and should not be understood as limiting the embodiments of the present invention and the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can also adopt other obvious technical solutions based on the contents disclosed in the claims of this application and its specification, including technical solutions that adopt any obvious replacements and modifications made to the embodiments described herein.

[0075] The chemical reagents used in the examples and comparative examples of the present invention are all commercially available products without further purification or treatment.

[0076] Example 1

[0077] This embodiment provides a low-ash, low-sulfur automotive lubricant and a preparation method thereof. The preparation method of the low-ash, low-sulfur automotive lubricant specifically comprises the following steps:

[0078] S1: Dispersing 20 wt.% polyisobutylene succinic anhydride in toluene and stirring at a constant temperature of 120°C to obtain dispersion A, to which a 10 wt.% toluene solution of polyamidoamine was added dropwise to obtain reaction solution B, wherein the molar ratio of polyisobutylene succinic anhydride to polyamidoamine was 1:0.45. After stirring and reacting for 4.5 hours, the primary amphiphilic polymer backbone was obtained by rotary evaporation under reduced pressure;

[0079] S2: A primary amphiphilic polymer backbone was dispersed in anhydrous xylene at a mass fraction of 20 wt.%, and stirred at a constant temperature of 80°C to obtain dispersion C. A xylene solution of N-(2-aminoethyl)maleimide at a mass fraction of 14 wt.% was added dropwise to obtain reaction solution D, wherein the molar ratio of the primary amphiphilic polymer backbone to N-(2-aminoethyl)maleimide was 1:0.15. The mixture was stirred for 1 h, and then the temperature was raised to 110°C to obtain reaction solution E, to which 8 wt.% of N-(2-aminoethyl)maleimide was added dropwise. % 2,5-bis(aminomethyl)furan in toluene to obtain reaction solution F, wherein the molar ratio of N-(2-aminoethyl)maleimide to 2,5-bis(aminomethyl)furan is 1:1.1, and the mixture is stirred for reaction for 2.8 hours, then cooled to 60°C to obtain reaction solution G, and p-methylbenzaldehyde is added, wherein the amount of p-methylbenzaldehyde is 8% of the mass of the primary amphiphilic polymer backbone, and the stirring reaction is continued for 1.8 hours, and the mixture is rotary evaporated and dried to obtain a biomimetic supramolecular self-assembly detergent;

[0080] S3: Ti3C2TxMXene powder was treated with a UV / O3 processor to obtain a pre-treated powder, wherein the ozone concentration during the treatment was 80 ppm and the treatment time was 30 min; a toluene dispersion of the pre-treated powder with a mass fraction of 2 wt.% was prepared, and a toluene solution of tributyl borate with a mass fraction of 5 wt.% was added to obtain a reaction solution H, wherein the mass ratio of the pre-treated powder to tributyl borate was 1:3, and the mixture was stirred and reacted at a constant temperature of 60°C for 3 h under sulfuric acid catalysis, centrifuged, washed, and dried to obtain a partially boron-modified MXene powder;

[0081] S4: partially boron-modified MXene powder and fluoroalkylsilane 1H,1H,2H,2H-perfluorodecyltriethoxysilane are dispersed in a toluene / water solution at a mass ratio of 1:1 to obtain a reaction solution I, wherein the mass fraction of the partially boron-modified MXene powder in toluene is 1 wt.%, and the mixture is reacted at a constant temperature of 95°C for 2 h, filtered, washed, and dried to obtain a modified MXene-based anti-wear and friction reducer;

[0082] S5: The bionic supramolecular self-assembly detergent and the modified MXene-based anti-wear and friction reducer are dispersed in the synthetic PAO, and the antioxidant alkylated diphenylamine is added, and the antioxidant dosage is 0.3% of the mass of the synthetic PAO, and the defoaming agent SAG47 is added, and the defoaming agent dosage is 0.04% of the mass of the synthetic PAO and mixed evenly to obtain a low-ash and low-sulfur automotive lubricant, wherein the mass ratio of the synthetic PAO, the bionic supramolecular self-assembly detergent and the modified MXene-based anti-wear and friction reducer is 100:4:0.5.

[0083] Example 2

[0084] This embodiment provides a low-ash, low-sulfur automotive lubricant and a preparation method thereof. The preparation method of the low-ash, low-sulfur automotive lubricant specifically comprises the following steps:

[0085] S1: Dispersing 25 wt.% polyisobutylene succinic anhydride in toluene and stirring at a constant temperature of 128°C to obtain dispersion A, to which a 15 wt.% toluene solution of polyamidoamine was added dropwise to obtain reaction solution B, wherein the molar ratio of polyisobutylene succinic anhydride to polyamidoamine was 1:0.5. After stirring and reacting for 4.8 hours, the primary amphiphilic polymer backbone was obtained by rotary evaporation under reduced pressure;

[0086] S2: The primary amphiphilic polymer backbone was dispersed in anhydrous xylene at a mass fraction of 15 wt.%, and stirred at a constant temperature of 88 ° C to obtain a dispersion C, and a xylene solution of N-(2-aminoethyl)maleimide with a mass fraction of 10 wt.% was added dropwise to obtain a reaction solution D, wherein the molar ratio of the primary amphiphilic polymer backbone to N-(2-aminoethyl)maleimide was 1:0.1. After stirring for 1.8 h, the temperature was raised to 115 ° C to obtain a reaction solution E, and a mass fraction of A 7 wt.% toluene solution of 2,5-bis(aminomethyl)furan was prepared to obtain a reaction solution F, wherein the molar ratio of N-(2-aminoethyl)maleimide to 2,5-bis(aminomethyl)furan was 1:1. The mixture was stirred for reaction for 2 hours, and then cooled to 70°C to obtain a reaction solution G. p-Tolualdehyde was added, wherein the amount of p-Tolualdehyde was 5% of the mass of the primary amphiphilic polymer backbone. The mixture was stirred for reaction for 1 hour, and then rotary evaporated and dried to obtain a biomimetic supramolecular self-assembly detergent.

[0087] S3: Ti3C2TxMXene powder was treated with a UV / O3 processor to obtain a pre-treated powder, wherein the ozone concentration during the treatment was 85 ppm and the treatment time was 40 min; a toluene dispersion of the pre-treated powder with a mass fraction of 2.5 wt.% was prepared, and a toluene solution of tributyl borate with a mass fraction of 8 wt.% was added to obtain a reaction solution H, wherein the mass ratio of the pre-treated powder to tributyl borate was 1:2, and the mixture was stirred and reacted at a constant temperature of 70°C for 4 h under sulfuric acid catalysis, centrifuged, washed, and dried to obtain a partially boronized MXene powder;

[0088] S4: Dispersing partially boron-modified MXene powder and fluoroalkylsilane 1H,1H,2H,2H-perfluorodecyltriethoxysilane in a toluene / water solution at a mass ratio of 1:1.1 to obtain reaction solution I, wherein the mass fraction of partially boron-modified MXene powder in toluene is 1.1 wt.%, reacting at a constant temperature of 80°C for 2.5 h, filtering, washing, and drying to obtain a modified MXene-based anti-wear and friction reducer;

[0089] S5: The bionic supramolecular self-assembly detergent and the modified MXene-based anti-wear and friction reducer are dispersed in the synthetic PAO, and the antioxidant IRGANOXL135 is added, and the antioxidant dosage is 0.1% of the mass of the synthetic PAO, and the defoaming agent SAG47 is added, and the defoaming agent dosage is 0.01% of the mass of the synthetic PAO, and the mixture is evenly mixed to obtain a low-ash and low-sulfur automotive lubricant, wherein the mass ratio of the synthetic PAO, the bionic supramolecular self-assembly detergent and the modified MXene-based anti-wear and friction reducer is 100:4.6:0.3.

[0090] Example 3

[0091] This embodiment provides a low-ash, low-sulfur automotive lubricant and a preparation method thereof. The preparation method of the low-ash, low-sulfur automotive lubricant specifically comprises the following steps:

[0092] S1: Dispersing 28 wt.% polyisobutylene succinic anhydride in toluene and stirring at a constant temperature of 125°C to obtain dispersion A, to which a 17 wt.% toluene solution of polyamidoamine was added dropwise to obtain reaction solution B, wherein the molar ratio of polyisobutylene succinic anhydride to polyamidoamine was 1:0.3. After stirring and reacting for 4 hours, vacuum rotary evaporation was performed to obtain a primary amphiphilic polymer backbone;

[0093] S2: A primary amphiphilic polymer backbone was dispersed in anhydrous xylene at a mass fraction of 25 wt.%, and stirred at a constant temperature of 90°C to obtain a dispersion C. A xylene solution of N-(2-aminoethyl)maleimide at a mass fraction of 12 wt.% was added dropwise to obtain a reaction solution D, wherein the molar ratio of the primary amphiphilic polymer backbone to N-(2-aminoethyl)maleimide was 1:0.2. The mixture was stirred for 2 h, and then heated to 118°C to obtain a reaction solution E. A mass fraction of 5 wt.% of N-(2-aminoethyl)maleimide was added dropwise to obtain a reaction solution D. % 2,5-bis(aminomethyl)furan in toluene to obtain reaction solution F, wherein the molar ratio of N-(2-aminoethyl)maleimide to 2,5-bis(aminomethyl)furan is 1:1.2, stirring and reacting for 2.5 hours, then cooling to 65°C to obtain reaction solution G, adding p-methylbenzaldehyde, wherein the amount of p-methylbenzaldehyde is 10% of the mass of the primary amphiphilic polymer backbone, and continuing to stir and react for 2 hours, rotary evaporation, and drying to obtain a biomimetic supramolecular self-assembly detergent;

[0094] S3: Ti3C2TxMXene powder was treated with a UV / O3 processor to obtain a pre-treated powder, wherein the ozone concentration during the treatment was 50 ppm and the treatment time was 45 min; a toluene dispersion of the pre-treated powder with a mass fraction of 1 wt.% was prepared, and a toluene solution of tributyl borate with a mass fraction of 7 wt.% was added to obtain a reaction solution H, wherein the mass ratio of the pre-treated powder to tributyl borate was 1:3.5, and the mixture was stirred and reacted at a constant temperature of 75°C under sulfuric acid catalysis for 3.5 h, centrifuged, washed, and dried to obtain a partially boronized MXene powder;

[0095] S4: Partially boron-modified MXene powder and fluoroalkylsilane 1H,1H,2H,2H-perfluorodecyltriethoxysilane are dispersed in a toluene / water solution at a mass ratio of 1:0.8 to obtain a reaction solution I, wherein the mass fraction of the partially boron-modified MXene powder in toluene is 0.8 wt.%, and the mixture is reacted at a constant temperature of 90°C for 2.8 h, filtered, washed, and dried to obtain a modified MXene-based anti-wear and friction reducer;

[0096] S5: The bionic supramolecular self-assembly detergent and the modified MXene-based anti-wear and friction reducer are dispersed in the synthetic PAO, and the antioxidant alkylated diphenylamine is added, and the antioxidant dosage is 0.4% of the synthetic PAO mass, and the defoaming agent SAG47 is added, and the defoaming agent dosage is 0.05% of the synthetic PAO mass and mixed evenly to obtain a low-ash and low-sulfur automotive lubricant, wherein the mass ratio of the synthetic PAO, the bionic supramolecular self-assembly detergent and the modified MXene-based anti-wear and friction reducer is 100:3:0.8.

[0097] Example 4

[0098] This embodiment provides a low-ash, low-sulfur automotive lubricant and a preparation method thereof. The preparation method of the low-ash, low-sulfur automotive lubricant specifically comprises the following steps:

[0099] S1: Dispersing 30 wt.% polyisobutylene succinic anhydride in toluene and stirring at a constant temperature of 130°C to obtain dispersion A, to which a 20 wt.% toluene solution of polyamidoamine was added dropwise to obtain reaction solution B, wherein the molar ratio of polyisobutylene succinic anhydride to polyamidoamine was 1:0.6. After stirring and reacting for 5 h, the primary amphiphilic polymer backbone was obtained by rotary evaporation under reduced pressure;

[0100] S2: The primary amphiphilic polymer backbone was dispersed in anhydrous xylene at a mass fraction of 23 wt.%, and stirred at a constant temperature of 85°C to obtain a dispersion C. A xylene solution of N-(2-aminoethyl)maleimide with a mass fraction of 15 wt.% was added dropwise to obtain a reaction solution D, wherein the molar ratio of the primary amphiphilic polymer backbone to N-(2-aminoethyl)maleimide was 1:0.18. After stirring for 1.5 h, the temperature was raised to 120°C to obtain a reaction solution E. A mass fraction of 10 wt.% was added dropwise to obtain a dispersion C. .% 2,5-bis(aminomethyl)furan in toluene to obtain reaction solution F, wherein the molar ratio of N-(2-aminoethyl)maleimide to 2,5-bis(aminomethyl)furan is 1:1.15, and after stirring for 3 hours, the mixture is cooled to 68°C to obtain reaction solution G, and p-methylbenzaldehyde is added, wherein the amount of p-methylbenzaldehyde is 7.5% of the mass of the primary amphiphilic polymer backbone, and the stirring reaction is continued for 1.5 hours, and the mixture is rotary evaporated and dried to obtain a biomimetic supramolecular self-assembly detergent;

[0101] S3: Ti3C2TxMXene powder was treated with a UV / O3 processor to obtain a pre-treated powder, wherein the ozone concentration during the treatment was 100 ppm and the treatment time was 50 min; a toluene dispersion of the pre-treated powder with a mass fraction of 3 wt.% was prepared, and a toluene solution of tributyl borate with a mass fraction of 10 wt.% was added to obtain a reaction solution H, wherein the mass ratio of the pre-treated powder to tributyl borate was 1:4, and the mixture was stirred and reacted at a constant temperature of 80°C under sulfuric acid catalysis for 3.8 h, centrifuged, washed, and dried to obtain a partially boronized MXene powder;

[0102] S4: partially boron-modified MXene powder and fluoroalkylsilane 1H,1H,2H,2H-perfluorodecyltriethoxysilane are dispersed in a toluene / water solution at a mass ratio of 1:1.2 to obtain a reaction solution I, wherein the mass fraction of the partially boron-modified MXene powder in toluene is 1.2 wt.%, and the reaction is carried out at a constant temperature of 100°C for 3 h. The modified MXene-based anti-wear and friction reducer is obtained by filtering, washing, and drying.

[0103] S5: The bionic supramolecular self-assembly detergent and the modified MXene-based anti-wear and friction reducer are dispersed in the synthetic PAO, and the antioxidant IRGANOXL135 is added, and the antioxidant dosage is 0.5% of the mass of the synthetic PAO, and the defoaming agent SAG47 is added, and the defoaming agent dosage is 0.025% of the mass of the synthetic PAO and mixed evenly to obtain a low-ash and low-sulfur automotive lubricant, wherein the mass ratio of the synthetic PAO, the bionic supramolecular self-assembly detergent and the modified MXene-based anti-wear and friction reducer is 100:5:0.6.

[0104] Comparative Example 1

[0105] This comparative example provides a low-ash, low-sulfur automotive lubricant. The difference from Example 1 is that in S5, the mass ratio of the synthetic PAO, the biomimetic supramolecular self-assembly detergent, and the modified MXene-based anti-wear and friction reducer is 100:8:0.5, and the other operating steps and process parameters are exactly the same as those in Example 1.

[0106] Comparative Example 2

[0107] This comparative example provides a low-ash, low-sulfur automotive lubricant. The difference from Example 1 is that in S5, the mass ratio of the synthetic PAO, the biomimetic supramolecular self-assembly detergent, and the modified MXene-based anti-wear and friction reducer is 100:1:0.5, and the other operating steps and process parameters are exactly the same as those in Example 1.

[0108] Comparative Example 3

[0109] This comparative example provides a low-ash, low-sulfur automotive lubricant. The difference from Example 1 is that in S5, the mass ratio of the synthetic PAO, the biomimetic supramolecular self-assembly detergent, and the modified MXene-based anti-wear and friction reducer is 100:8:1, and the other operating steps and process parameters are exactly the same as those in Example 1.

[0110] Comparative Example 4

[0111] This comparative example provides a low-ash, low-sulfur automotive lubricant. The difference from Example 1 is that in S5, the mass ratio of the synthetic PAO, the biomimetic supramolecular self-assembly detergent, and the modified MXene-based anti-wear and friction reducer is 100:8:0.1, and the other operating steps and process parameters are exactly the same as those in Example 1.

[0112] The performance test of the low-ash, low-sulfur automotive lubricants of Examples 1-4 and Comparative Examples 1-4 was conducted, and the specific process is as follows:

[0113] Refer to ASTM D5707 to test the friction coefficient of the sample;

[0114] Test the oxidation stability of samples according to GB / T12581-2006;

[0115] Test the total base value of the sample according to SH / T0688-2000;

[0116] The sulfated ash content of the sample was tested according to GB / T2433-2001;

[0117] The test results are shown in Table 1.

[0118] Table 1 Performance test results of low ash and low sulfur automotive lubricants of Examples 1-4 and Comparative Examples 1-4

[0119]

[0120] From the test results of Example 1 and Comparative Examples 1 and 2, it can be seen that when the mass fraction of the bionic supramolecular self-assembly detergent is too high, the excess detergent molecules form large-sized micelles that interfere with the formation of the lubricating film, causing the friction coefficient to increase to 0.085; the excess active groups have increased opportunities to contact oxygen, resulting in a decrease in the oxidative stability to 670h; the excess amino functional groups in the detergent provide excessive alkaline reserves, causing the total base number to increase to 7.0mgKOH / g; when the mass fraction of the bionic supramolecular self-assembly detergent is too low, the insufficient number of self-assembled structures leads to limited formation of the protective film, causing the friction coefficient to increase to 0.082; the synergistic antioxidant effect of the detergent is insufficient, resulting in a decrease in the oxidative stability to 750h; insufficient alkaline reserves cause the total base number to decrease to 3.5mgKOH / g.

[0121] From the test results of Example 1 and Comparative Examples 3 and 4, it can be seen that when the mass fraction of the modified MXene-based anti-wear and friction reducer is too high, the excessive MXene nanosheets agglomerate, resulting in an increase in interfacial shear stress, causing the friction coefficient to increase to 0.084; the increase in surface active sites accelerates oxidation, causing the oxidation stability to decrease to 780h; there is no significant effect on the total base number, which is maintained at 4.7mgKOH / g; when the mass fraction of the modified MXene-based anti-wear and friction reducer is too low, the insufficient number of nanosheets affects the continuity of the lubricating film, causing the friction coefficient to increase to 0.083; the effect on the oxidation stability is small, basically maintained at 876h; the total base number remains basically unchanged at 4.8mgKOH / g.

[0122] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a low-ash, low-sulfur automotive lubricant, characterized in that: The preparation method comprises: S1: Dispersing polyisobutylene succinic anhydride in toluene, stirring and dispersing, and then adding polyamidoamine to react to obtain a primary amphiphilic polymer backbone; S2: After reacting the primary amphiphilic polymer skeleton with N-(2-aminoethyl)maleimide, 2,5-bis(aminomethyl)furan was added to react, the temperature was lowered to obtain a reaction solution G, and p-methylbenzaldehyde was added to react to obtain a biomimetic supramolecular self-assembled detergent; S3: Treating Ti3C2TxMXene powder with a UV / O3 processor to obtain pre-treated powder; reacting the pre-treated powder with tributyl borate to obtain partially boronated MXene powder; S4: reacting partially boronized MXene powder with fluoroalkylsilane 1H,1H,2H,2H-perfluorodecyltriethoxysilane to obtain a modified MXene-based anti-wear and friction reducer; S5: The biomimetic supramolecular self-assembly detergent and the modified MXene-based anti-wear and friction reducer are dispersed in the synthetic PAO, and an antioxidant and a defoaming agent are added and mixed evenly to obtain a low-ash and low-sulfur automotive lubricant.

2. The method for preparing a low-ash and low-sulfur automotive lubricant according to claim 1, characterized in that: In S1: the molar ratio of the polyisobutylene succinic anhydride to the polyamidoamine is 1:(0.3-0.6).

3. The method for preparing a low-ash and low-sulfur automotive lubricant according to claim 1, characterized in that: In S2: the molar ratio of the primary amphiphilic polymer backbone to N-(2-aminoethyl)maleimide is 1:(0.1-0.2).

4. The method for preparing a low-ash and low-sulfur automotive lubricant according to claim 1, characterized in that: In S2, the molar ratio of N-(2-aminoethyl)maleimide to 2,5-bis(aminomethyl)furan is 1:(1-1.2).

5. The method for preparing a low-ash and low-sulfur automotive lubricant according to claim 1, characterized in that: In S2: the feeding amount of the p-tolualdehyde is 5-10% of the mass of the primary amphiphilic polymer skeleton.

6. The method for preparing a low-ash and low-sulfur automotive lubricant according to claim 1, characterized in that: In S3: the mass ratio of the pre-treated powder to tributyl borate is 1:(2-4).

7. The method for preparing a low-ash and low-sulfur automotive lubricant according to claim 1, characterized in that: In S4: the mass ratio of the partially boronated MXene powder to the fluoroalkylsilane is 1:(0.8-1.2).

8. The method for preparing a low-ash and low-sulfur automotive lubricant according to claim 1, characterized in that: In S5: The antioxidant is any one of alkylated diphenylamine and IRGANOXL135 or a combination of the two; The dosage of the antioxidant is 0.1-0.5% of the mass of the synthesized PAO; The defoaming agent is SAG47, and the feeding amount of the defoaming agent is 0.01-0.05% of the mass of the synthesized PAO.

9. The method for preparing a low-ash and low-sulfur automotive lubricant according to claim 1, characterized in that: In S5: the mass ratio of the synthetic PAO, the biomimetic supramolecular self-assembly detergent and the modified MXene-based anti-wear and friction reducer is 100: (3-5): (0.3-0.8).

10. A low-ash and low-sulfur automotive lubricant prepared by the preparation method according to any one of claims 1 to 9.

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