A lubricating oil adsorbed onto internal engine components and used to increase machine life, and its preparation method.

Abstract

This invention relates to the field of high-performance lubricating materials, specifically disclosing a lubricating oil that adsorbs onto internal engine components and increases machine life, as well as its preparation method. By mass percentage, the lubricating oil comprises the following raw materials: 1-10% polymerizable functional monomers, 1-2% initiator, 0.1-0.9% regulator, 0.2-0.4% rust inhibitor, 0.1-0.9% ashless antioxidant, 0.01-0.09% defoamer, with the balance being base oil. This invention, through the synergistic design of polymerizable functional monomers and a controllable initiation-regulation system, converts frictional heat and mechanical energy into a driving force for constructing a high-strength protective film, effectively solving the environmental problems of ZDDP in traditional engine lubricating oils and the application challenges of nanoparticles.

Description

Technical Field

[0001] This invention belongs to the field of high-performance lubricating materials, specifically relating to a lubricating oil that can be adsorbed onto internal engine components and increase machine life, and its preparation method. Background Technology

[0002] Traditional engine lubricants rely primarily on the synergistic effect of functional chemical additives for their anti-wear and extreme pressure protection mechanisms. Zinc dialkyl dithiophosphate (ZDDP), since its introduction in the 1940s, has been the most widely used and comprehensive multi-functional additive in internal combustion engine oils. The thiophosphate groups in its molecular structure decompose through thermal oxidation on the friction surface, reacting chemically with the iron matrix to generate an amorphous zinc phosphate glass film (Zn-Fe-PO glassy network structure) and a ferrous sulfide (FeS) composite layer. This composite layer effectively reduces the coefficient of friction and provides lubrication. Although traditional phosphorus and sulfur-containing additives such as ZDDP exhibit excellent performance (patent CN103249821B discloses dithiocarbamate), they cannot meet the low SAPS (Sulfated Ash, Phosphorus, Sulfur) requirements of new environmental regulations.

[0003] In recent years, with the penetration of nanotechnology, significant progress has been made in the research of nanoscale functional materials as lubricant additives. Rare earth oxides such as nano-cerium dioxide exhibit excellent antioxidant activity and tribocatalytic properties due to their unique redox cycle capabilities, and can improve the internal surface quality of engines through a chemical mechanical polishing mechanism. In addition, low-dimensional nanomaterials such as carbon nanotubes, graphene, and metal sulfide nanosheets (such as WS2 and MoS2) have also been extensively explored, aiming to utilize their nanoscale effect and layered structure to achieve friction reduction and wear resistance.

[0004] However, the practical application of nano-additives faces multiple engineering obstacles. The primary issue is stability and agglomeration tendency: nanoparticles possess extremely high specific surface area and surface energy, making them highly susceptible to irreversible agglomeration driven by van der Waals forces, magnetic attraction, or chemical bonding, forming micron-sized secondary particles. This not only negates the nano-effect but also clogs oil filters, increases pumping resistance, and can even lead to oil circuit malfunctions. While surface modification can improve dispersibility (CN102559339B discloses surface-modified SnO nano-additives), it sacrifices particle reactivity or increases the low-temperature viscosity of the oil. Secondly, the transport of nanoparticles in lubricating oil mainly relies on convection and Brownian motion; their migration to wear areas is random and non-directional. In elastohydrodynamic or hydrodynamic lubrication zones, nanoparticles are isolated by the oil film, making effective contact with the friction surface difficult. Only under extreme boundary lubrication conditions can particles enter the contact area through compression, and most particles flow back with the oil after friction, unable to remain in the wear area to exert a repair effect.

[0005] Based on the above description, the present invention aims to provide an engine lubricant with low SAPS and no solid particle deposition, solving the environmental deficiencies of existing engine lubricants and the problems of agglomeration, deposition and filtration of nano-additives. Summary of the Invention

[0006] To address the aforementioned issues, this invention provides a lubricating oil that does not rely on phosphorus, sulfur, or zinc elements and contains no solid particles. This lubricating oil meets the requirements of low SAPS and long oil change intervals, while avoiding the problems of agglomeration, deposition, and filtration associated with nano-additives. During engine operation, it can generate a strong, dense, and self-healing polymer protective film on the metal friction surface through mechano-chemical interactions in the friction contact area, thereby reducing wear and extending engine life.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides a lubricating oil that can be adsorbed onto internal engine components and increase machine life. By weight percentage, it contains the following raw materials: 1-10% polymerizable functional monomers, 1-2% initiator, 0.1-0.9% regulator, 0.2-0.4% rust inhibitor, 0.1-0.9% ashless antioxidant, 0.01-0.09% defoamer, and the balance being base oil.

[0008] The lubricating oil provided by this invention, through the synergistic design of polymerizable functional monomers and a controllable initiation-regulation system, converts frictional heat and mechanical energy into a driving force for building a high-strength protective film, effectively solving the environmental problems of ZDDP in traditional engine lubricating oils and the application challenges of nanoparticles. In the normal lubrication range, the oil temperature remains below the initiator decomposition threshold, effectively maintaining the stability of the oil system. When entering the friction boundary state, the contact of micro-protrusions generates localized high pressure (>1 GPa) and flash temperature (>200℃). Under these extreme conditions, the initiator decomposes to generate a high concentration of free radicals, the regulator temporarily deactivates, and the polymerizable functional monomers accumulate at the concentration of the newly formed metal active surface. The combination of these three factors efficiently and selectively triggers polymerization at wear risk points, forming a polymer film.

[0009] In some embodiments, the initiator is a peroxide.

[0010] Peroxides have a high thermal decomposition temperature (>120°C), which matches the local flash temperature of engine friction (up to 300°C or higher); in the oil sump and most lubrication areas, the oil temperature (<120°C) is insufficient to decompose them. They only decompose rapidly in high-temperature micro-regions at the moment of frictional contact, generating free radicals that trigger monomer polymerization.

[0011] In some embodiments, the regulator is 4-methoxyphenol.

[0012] 4-Methoxyphenol is a highly efficient free radical scavenger. At low temperatures in oil, it can effectively quench accidentally generated free radicals, ensuring the stability of the oil during storage and circulation and preventing viscosity growth. In the high-temperature friction zone, its polymerization inhibition effect is weakened, allowing free radicals generated by the initiator to initiate effective polymerization.

[0013] In some embodiments, the ashless antioxidant is a high molecular weight phenolic ester antioxidant; the rust inhibitor is dodecenyl succinate half ester; and the defoamer is a polysiloxane.

[0014] Ashless antioxidants, rust inhibitors, and defoamers serve as functional additives, providing necessary auxiliary protection and ensuring the overall performance of the oil.

[0015] In some embodiments, the preparation steps of the polymerizable functional monomer are as follows: S1. Stir oleic acid, toluene and catalyst and heat to 50-60℃, add hydrogen peroxide with a concentration of 45-55wt% dropwise, stir for 5-7h; allow to stand and separate into layers, wash the organic phase, and distill under reduced pressure to obtain epoxy stearic acid. S2. Epoxy stearic acid, hydroxyethyl methacrylate, catalyst, polymerization inhibitor and cyclohexane are reacted at 80-85℃ for 5-7h under nitrogen protection. The disappearance of epoxy groups is monitored by TLC. The mixture is cooled to 50-60℃ and the pH is neutralized to 7-8. The mixture is separated, the organic phase is washed, dried, adsorbed, filtered and the film is evaporated to obtain the polymerizable functional monomer.

[0016] In some embodiments, in step S1, the catalyst accounts for 5%-7% of the mass of oleic acid.

[0017] In some embodiments, in step S2, the mass ratio of epoxy stearic acid to hydroxyethyl methacrylate is 1:(0.4-0.5).

[0018] In some embodiments, in step S2, the catalyst accounts for 0.3%-0.7% of the mass of epoxy stearic acid, and the polymerization inhibitor accounts for 0.1%-0.2% of the mass of epoxy stearic acid.

[0019] The polar groups in the functional comonomers bond with hydrogen bonds in the oxide layer of the metal surface, providing strong interfacial adhesion; simultaneously, the long-chain alkyl groups extend outward, forming a hydrophobic, low-shear surface. Under the localized high temperature and pressure of friction, the peroxide initiator decomposes to generate free radicals, triggering the polymerization of double bonds in the polymerizable functional monomers, forming an in-situ polymer film on the worn surface. This polymer film itself isolates the metal from direct contact, achieving friction reduction protection under moderate loads. If localized wear occurs due to extreme operating conditions, the exposed nascent metal surface will trigger the above polymerization process again during the next frictional contact, achieving film repair.

[0020] In some embodiments, the base oil is a polyalphaolefin.

[0021] Another aspect of the present invention provides a method for preparing the above-mentioned lubricating oil, comprising the following steps: mixing polymerizable functional monomers, initiators, regulators, rust inhibitors, ashless antioxidants, defoamers and base oils evenly.

[0022] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention provides a lubricating oil that can form an in-situ polymer protective film with anti-wear and friction-reducing properties on metal friction surfaces. This lubricating oil achieves extreme pressure anti-wear without relying on phosphorus, sulfur, or zinc elements, meeting the requirements of low SAPS and long oil change intervals. At the same time, it does not contain any solid particles, avoiding the problems of agglomeration, deposition, and filtration of nano-additives. Furthermore, it is combined with a controllable initiation and regulation system to ensure the stability of the oil itself, reduce the risk of gelation or polymerization clogging, and provide more environmentally friendly and long-lasting protection for the engine, fundamentally extending the life of key moving parts.

[0023] 2. This invention achieves controllable and adaptive polymerization of polymerizable functional monomers through initiators and regulators, which is triggered in the high-temperature and high-stress friction micro-regions that need protection, while remaining stable in the oil tank body, thus avoiding abnormal growth in oil viscosity; the formed polymer protective film has good self-healing ability, and when the local film layer is damaged due to extreme working conditions, it can be repaired by triggering the polymerization of new monomers through subsequent friction. Detailed Implementation

[0024] The present invention will be described below with reference to specific implementation schemes. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. It is worth noting that, unless otherwise specified, the raw materials used in the following preparation examples and embodiments can be from any commercially available manufacturer.

[0025] Preparation Example 1 The preparation steps of polymerizable functional monomer A are as follows: S1. Stir 282g of oleic acid, 200mL of toluene and 17g of formic acid and heat to 55℃. Add 82g of 50wt% hydrogen peroxide dropwise over 2h and stir for 6h. Allow the mixture to stand and separate into layers. Discard the lower aqueous phase. Wash the organic phase with 5wt% sodium carbonate solution and then wash with water until neutral. Remove toluene by vacuum distillation (70℃, 50mbar) to obtain epoxy stearic acid. S2. 298g of epoxy stearic acid, 130g of hydroxyethyl methacrylate, 1.5g of boron trifluoride diethyl ether complex, 0.5g of phenothiazine, and 250mL of cyclohexane were reacted at 82℃ for 6h under nitrogen protection. The disappearance of epoxy groups was monitored by TLC. The mixture was cooled to 55℃, and 5wt% sodium bicarbonate solution was added to neutralize the pH to 7.5. The mixture was separated, the organic phase was washed with water, dried with anhydrous magnesium sulfate, adsorbed by activated carbon, filtered, and evaporated through a thin film (80℃, 20mbar) to obtain polymerizable functional monomer A.

[0026] Preparation Example 2 The preparation steps of polymerizable functional monomer B differ from those in Preparation Example 1 in that the amount of hydroxyethyl methacrylate used is 104g.

[0027] Preparation Example 3 The preparation steps of polymerizable functional monomer C differ from those in Preparation Example 1 in that the amount of hydroxyethyl methacrylate used is 164g.

[0028] Example 1 A lubricating oil that is adsorbed onto internal engine components and increases machine life, comprising, by weight percentage (100%), the following raw materials: 6% polymerizable functional monomer A, 1.5% dicumyl peroxide, 0.5% 4-methoxyphenol, 0.3% rust inhibitor (dodecenyl succinate half ester), 0.5% ashless antioxidant (AO-1135), 0.05% polysiloxane (Shandong Luderui, model 8114), with the balance being base oil (polyalphaolefin, model PAO-6).

[0029] The method for preparing the lubricating oil in this embodiment includes the following steps: Simply mix polymerizable functional monomer A, dicumyl peroxide, 4-methoxyphenol, rust inhibitor, ashless antioxidant, polysiloxane and base oil evenly.

[0030] Example 2 A lubricating oil that is adsorbed onto internal engine components and increases machine life, comprising, by weight percentage (100%), the following raw materials: 3% polymerizable functional monomer A, 1% dicumyl peroxide, 0.1% 4-methoxyphenol, 0.2% rust inhibitor (dodecenyl succinate half ester), 0.1% ashless antioxidant (AO-1135), 0.01% polysiloxane (Shandong Luderui, model 8114), with the balance being base oil (polyalphaolefin, model PAO-6).

[0031] The preparation method of the lubricating oil in this embodiment is the same as in Embodiment 1.

[0032] Example 3 A lubricating oil that is adsorbed onto internal engine components and increases machine life, comprising, by weight percentage (100%), the following raw materials: 10% polymerizable functional monomer A, 2% dicumyl peroxide, 0.9% 4-methoxyphenol, 0.4% rust inhibitor (dodecenyl succinate half ester), 0.9% ashless antioxidant (AO-1135), 0.09% polysiloxane (Shandong Luderui, model 8114), with the balance being base oil (polyalphaolefin, model PAO-6).

[0033] The preparation method of the lubricating oil in this embodiment is the same as in Embodiment 1.

[0034] Example 4 This embodiment provides a lubricating oil that is adsorbed onto internal engine components and increases machine life, and its preparation method. The specific implementation method is the same as in Embodiment 1, except that polymerizable functional monomer A in the raw materials is replaced by an equal amount of polymerizable functional monomer B.

[0035] Example 5 This embodiment provides a lubricating oil that is adsorbed onto internal engine components and increases machine life, and its preparation method. The specific implementation method is the same as in Embodiment 1, except that the polymerizable functional monomer A in the raw material is replaced by an equal amount of polymerizable functional monomer C.

[0036] Comparative Example 1 This comparative example provides a lubricating oil that can be adsorbed onto internal engine components and increase machine life, and its preparation method. The specific implementation method is the same as that in Example 1, except that: the polymerizable functional monomer A in the raw materials is replaced by an equal amount of a reactive monomer mixture, which contains octadecyl methacrylate, hydroxyethyl acrylate and ethylene glycol dimethacrylate in a mass ratio of 70:25:5.

[0037] Performance testing Examples 1-5, Comparative Example 1, and API SP 5W-30 fully synthetic commercial motor oil (control sample) were selected as test samples and the following tests were conducted. The results are shown in Table 1.

[0038] 1. Thin Film Adsorption and Polymerization Test: Using atomic force microscopy (AFM) in triboelectric mode, we observed whether in-situ polymerization formed a polymer film. Specific conditions are as follows: Upper sample: φ4mm GCr15 bearing steel ball, surface polished to Ra<0.01μm, and ultrasonically cleaned with acetone and ethanol; Sample preparation: Polished AISI 52100 steel disc (Ra<0.02μm), ultrasonically cleaned with acetone and ethanol; Procedure: Select a 10μm×10μm region and scan with a standard silicon probe to obtain the original morphology image; drop 2μL of sample onto the selected region, switch to tribological microscopy mode, set the normal load to 300nN, perform 100 linear reciprocating scans at a frequency of 1Hz, with a scan length of 8μm, after the tribological process is completed, switch back to the standard silicon probe, scan again to obtain the morphology image after tribulation, and observe whether a polymer film is formed.

[0039] 2. Four-ball friction and wear test: Refer to standard GB / T3142-1982, load 392N, speed 1200rpm, oil temperature 75±2°C, test time 30min, steel ball is GCr15 standard steel ball with diameter of 12.7mm (first grade, hardness 64-66HRC), to obtain the average wear scar diameter (WSD).

[0040] 3. Engine bench durability test: bench (ASTM Sequence IVA), engine (Toyota 2AZ-FE test engine), test cycle (100 hours, running according to the speed-load cycle of Sequence IVA), after the test, the engine is completely disassembled; the maximum wear depth of the camshaft tip is measured (at least 8 camshafts are measured and the average value is taken), and the piston ring mass loss is measured.

[0041] Table 1 Performance Test Results As shown in Table 1, a uniform and continuous raised film layer appeared in the friction trajectory area of ​​Examples 1-3, with an average height between 50-150 nm. The content of polymerizable functional monomers affects the height of the film layer. Data from the four-ball friction and wear test and engine bench durability test show that this lubricant can provide effective anti-wear protection for the core moving parts of the engine, extending engine life. Compared to Example 1, the control sample showed slight material accumulation or transfer in the friction trajectory, with no raised film layer, and a WSD increase of approximately 25%. This indicates that the polymer film formed by the lubricant provided by this invention under extremely high contact stress can provide more effective anti-wear and friction-reducing protection.

[0042] Based on Examples 1 and 4-5, it can be seen that when preparing polymerizable functional monomers, reducing the amount of hydroxyethyl methacrylate may lead to insufficient polymerizable double bond density, limiting the growth of the friction polymerized film and affecting its anti-wear performance; while increasing the amount of hydroxyethyl methacrylate also leads to the deterioration of the friction polymerized film performance, possibly due to the decrease in film cohesion caused by the competition of copolymers.

[0043] Compared to the polymerizable functional monomer with integrated performance in Example 1, the three monomers physically mixed in Comparative Example 1 may deviate from the designed ratio in local composition due to differences in reactivity, adsorption strength, and diffusion rate during adsorption and polymerization on the friction surface. This affects the uniformity and performance consistency of the final polymer film, resulting in discontinuous and irregular film layers with a significantly reduced height, which in turn leads to increased wear.

[0044] The embodiments described above do not limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A lubricating oil that adsorbs onto internal engine components and increases machine life, characterized in that, By weight percentage (100%), it contains the following raw materials: 1-10% polymerizable functional monomers, 1-2% initiator, 0.1-0.9% regulator, 0.2-0.4% rust inhibitor, 0.1-0.9% ashless antioxidant, 0.01-0.09% defoamer, and the balance is base oil.

2. The lubricating oil according to claim 1, characterized in that, The initiator is a peroxide.

3. The lubricating oil according to claim 1, characterized in that, The regulator is 4-methoxyphenol.

4. The lubricating oil according to claim 1, characterized in that, The ashless antioxidant is a high molecular weight phenolic ester antioxidant; the rust inhibitor is dodecenyl succinate half ester; and the defoamer is a polysiloxane.

5. The lubricating oil according to claim 1, characterized in that, The preparation steps of the polymerizable functional monomer are as follows: S1. Stir oleic acid, toluene and catalyst and heat to 50-60℃, add hydrogen peroxide with a concentration of 45-55wt% dropwise, stir for 5-7h; allow to stand and separate into layers, wash the organic phase, and distill under reduced pressure to obtain epoxy stearic acid. S2. Epoxy stearic acid, hydroxyethyl methacrylate, catalyst, polymerization inhibitor and cyclohexane are reacted at 80-85℃ for 5-7h under nitrogen protection. The disappearance of epoxy groups is monitored by TLC. The mixture is cooled to 50-60℃ and the pH is neutralized to 7-8. The mixture is separated, the organic phase is washed, dried, adsorbed, filtered and the film is evaporated to obtain the polymerizable functional monomer.

6. The lubricating oil according to claim 5, characterized in that, In step S1, the catalyst accounts for 5%-7% of the mass of oleic acid.

7. The lubricating oil according to claim 5, characterized in that, In step S2, the mass ratio of epoxy stearic acid to hydroxyethyl methacrylate is 1:(0.4-0.5).

8. The lubricating oil according to claim 5, characterized in that, In step S2, the catalyst accounts for 0.3%-0.7% of the mass of epoxy stearic acid, and the polymerization inhibitor accounts for 0.1%-0.2% of the mass of epoxy stearic acid.

9. The lubricating oil according to claim 1, characterized in that, The base oil is a polyalphaolefin.

10. A method for preparing the lubricating oil according to any one of claims 1-9, characterized in that, The process includes the following steps: mixing polymerizable functional monomers, initiators, regulators, rust inhibitors, ashless antioxidants, defoamers, and base oils thoroughly.

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