Lubricating oil composition as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of lubricating oil, and particularly relates to a lubricating oil composition as well as a preparation method and application thereof. The lubricating oil composition comprises the following raw materials in parts by weight: 0.1-5 parts of a hydrocarbon compound, 0.1-5 parts of an emulsifier and 90-99.8 parts of a water phase, the water phase comprises the following raw materials: a compound containing a free amino functional group, an alcohol compound and water. The lubricating oil composition has the beneficial effects that the lubricating oil composition has good water-phase cooling and cleaning performance, abrasive dust and heat generated in the machining process can be effectively removed, and heating deformation of the metal surface is prevented. Meanwhile, the lubricating property of an oil phase is also kept, a stable oil film is formed on the surface of bearing steel, direct contact of the metal surface is prevented, the friction coefficient is remarkably reduced, and abrasion is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of lubricating oils, and particularly relates to a lubricating oil composition, a preparation method thereof, and an application thereof. Background Art

[0002] As an important lubricating medium, lubricating oil plays a crucial role in industrial applications. Lubricating oil is formed by two immiscible liquids (usually oil and water) through the action of surfactants, and is widely used in fields such as metal processing, mechanical operation, and bearing lubrication. Its core advantage lies in being able to combine the lubricating performance of oil with the cooling performance of water, providing a more efficient and economical lubrication solution.

[0003] In the application of metal materials such as bearing steel, the use of lubricating oil can significantly reduce the friction coefficient, reduce wear, extend the service life of equipment, and to a certain extent reduce the working temperature, thereby reducing the risk of thermal deformation and thermal damage. In addition, lubricating oil also has characteristics such as being easy to clean, having good biodegradability, and low environmental pollution, meeting the requirements of modern industry for environmental protection and sustainable development.

[0004] However, the performance of traditional lubricating oils is not ideal under extreme working conditions such as high load, high pressure, and high temperature, and their stability, anti-pollution ability, and reliability during long-term operation still need to be improved. Especially in the lubrication of key components such as bearing steel, the lubricating performance and long-term stability of lubricating oil are the keys to achieving efficient operation. Therefore, developing a new type of high-efficiency and low-friction lubricating oil that can maintain excellent lubricating performance under harsh working conditions is of great significance for improving industrial production efficiency and reducing maintenance costs. Summary of the Invention

[0005] The present application provides a lubricating oil composition, a preparation method thereof, and an application thereof, aiming to solve the problem that the performance of existing lubricating oils is not ideal under extreme working conditions.

[0006] The first aspect of the present application provides a lubricating oil composition, comprising the following raw materials in parts by weight: 0.1 - 5 parts of a hydrocarbon compound, 0.1 - 5 parts of an emulsifier, and 90 - 99.8 parts of an aqueous phase;

[0007] The aqueous phase comprises the following raw materials: a compound containing a free amino functional group, an alcohol compound, and water.

[0008] According to some embodiments of the lubricating oil composition of the present application, it comprises the following raw materials in parts by weight: 0.5 - 2 parts of a hydrocarbon compound, 0.5 - 2 parts of an emulsifier, and 96 - 99 parts of an aqueous phase;

[0009] The aqueous phase comprises the following raw materials in parts by weight: 0.8 - 1.2 parts of a compound containing a free amino functional group, 3 - 5 parts of an alcohol compound, and 4 - 6 parts of water.

[0010] In some embodiments of the lubricating oil composition according to the present application, the hydrocarbon compound includes one or more of alkanes having C1-C20, alkenes having C2-C20, alkanoic acids having C1-C20, and alkenoic acids having C2-C20.

[0011] In some embodiments of the lubricating oil composition according to the present application, the hydrocarbon compound includes one or more of alkenes having C3-C18 and alkenoic acids having C3-C18.

[0012] In some embodiments of the lubricating oil composition according to the present application, the emulsifier includes didodecyldimethyl cerium tetrachloride.

[0013] In some embodiments of the lubricating oil composition according to the present application, the compound containing a free amino functional group is polylysine.

[0014] In some embodiments of the lubricating oil composition according to the present application, the molecular weight of the polylysine is 3500-5500.

[0015] In some embodiments of the lubricating oil composition according to the present application, the alcohol compound includes one or more of ethylene glycol, propylene glycol, glycerol, and butanediol.

[0016] In some embodiments of the lubricating oil composition according to the present application, the alcohol compound includes ethylene glycol.

[0017] The second aspect of the present application provides a preparation method of the lubricating oil composition according to the first aspect of the present application, including the following steps: mixing a hydrocarbon compound, an emulsifier, and an aqueous phase to obtain the lubricating oil composition.

[0018] In some embodiments of the preparation method according to the present application, the mixing is ultrasonic mixing.

[0019] In some embodiments of the preparation method according to the present application, the temperature of the mixing is 40-50°C, and the time of the mixing is 0.5-1 h.

[0020] The third aspect of the present application provides an application of the lubricating oil composition according to the first aspect of the present application or the lubricating oil composition obtained by the preparation method according to the second aspect of the present application in lubricating bearing steel.

[0021] The beneficial effects of the present application include: The lubricating oil composition according to the present application has good aqueous phase cooling and cleaning performance, can effectively remove the grinding debris and heat generated during the processing, and prevent the metal surface from getting hot and deformed. At the same time, it also maintains the lubricating performance of the oil phase, forms a stable oil film on the surface of the bearing steel, prevents the direct contact of the metal surface, significantly reduces the friction coefficient, and reduces wear. Specific Embodiments

[0022] Embodiments of the present invention will be described in detail below. The examples of the embodiments are exemplary and are intended to explain the present invention, but should not be construed as limiting the present invention.

[0023] In the present invention, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0024] An embodiment of the present application provides a lubricating oil composition, comprising the following raw materials in parts by weight: 0.1 - 5 parts of a hydrocarbon compound, 0.1 - 5 parts of an emulsifier, and 90 - 99.8 parts of an aqueous phase; the aqueous phase comprises the following raw materials: a compound containing a free amino functional group, an alcohol compound, and water.

[0025] The core component of the lubricating oil composition described in the present application is the emulsifier, whose function is to reduce the interfacial tension between the oil phase and the aqueous phase, thereby forming a stable emulsion. Emulsifier molecules usually have two parts: a hydrophilic group and a lipophilic group. The lipophilic group will extend into the oil phase, while the hydrophilic group extends into the aqueous phase. Such emulsifier molecules arranged in an oriented manner form a protective film at the oil-water interface, preventing oil droplets from aggregating, thereby improving the stability of the lubricating oil composition. The aqueous phase serves as the continuous phase, providing a dispersion medium for the lubricating oil composition. It has a relatively high content in the lubricating oil composition and usually has good cooling performance. The solubility and adsorption ability of the emulsifier in the aqueous phase determine its contribution to the stability of the lubricating oil composition. The adsorption of the emulsifier in the aqueous phase can reduce the interfacial tension and prevent oil droplets from aggregating through electrostatic repulsion or steric hindrance. The oil phase and the aqueous phase are inherently immiscible, but through the action of the emulsifier, the oil phase can be dispersed in the aqueous phase in the form of tiny droplets. The properties of the oil phase (such as polarity, chain length, etc.) will affect the stability of the lubricating oil composition. For example, an oil phase containing polar groups can form a more stable interfacial composite film with the emulsifier, thereby improving the stability of the lubricating oil composition. Therefore, usually the oil phase has good film-forming ability and lubricating performance. The lubricating oil composition described in the present application has the cooling performance of the aqueous phase and also takes into account the lubricating performance of the oil phase, and has a wide range of uses in industrial applications.

[0026] In some embodiments of the present application, the raw materials include the following parts by weight: 0.5 - 2 parts of hydrocarbon compounds, 0.5 - 2 parts of emulsifiers, and 96 - 99 parts of aqueous phase; the aqueous phase includes the following parts by weight of raw materials: 0.8 - 1.2 parts of a compound containing a free amino functional group, 3 - 5 parts of an alcohol compound, and 4 - 6 parts of water.

[0027] In some embodiments of the present application, the raw materials include the following parts by weight: 0.8 - 1.8 parts of hydrocarbon compounds, 0.8 - 1.8 parts of emulsifiers, and 96.4 - 98.4 parts of aqueous phase; the aqueous phase includes the following parts by weight of raw materials: 0.8 - 1.2 parts of a compound containing a free amino functional group, 3 - 5 parts of an alcohol compound, and 4 - 6 parts of water.

[0028] In some embodiments of the present application, the raw materials include the following parts by weight: 1.2 - 1.5 parts of hydrocarbon compounds, 1.2 - 1.5 parts of emulsifiers, and 97 - 97.6 parts of aqueous phase; the aqueous phase includes the following parts by weight of raw materials: 0.8 - 1.2 parts of a compound containing a free amino functional group, 3 - 5 parts of an alcohol compound, and 4 - 6 parts of water.

[0029] In some embodiments of the present application, the hydrocarbon compounds include one or more of C1 - C20 alkanes, C2 - C20 alkenes, C1 - C20 alkanoic acids, and C2 - C20 alkenoic acids. These hydrocarbon compounds have good chemical stability and compatibility, relatively stable chemical properties, are not prone to oxidation or decomposition reactions, and are suitable for use in a variety of chemical environments. At the same time, they have good interfacial tension and emulsifying effect. The non - polar characteristics of alkanes and alkenes can reduce the interfacial tension between the oil phase and the aqueous phase, making the emulsification process easier to carry out. The carboxyl groups in alkanoic acids and alkenoic acids can interact with the hydrophilic groups of the emulsifier to further reduce the interfacial tension and improve the stability of the lubricating oil composition.

[0030] In some embodiments of the present application, the hydrocarbon compounds include one or more of C3 - C18 alkenes and C3 - C18 alkenoic acids.

[0031] In some embodiments of the present application, the emulsifier includes didodecyldimethyl cerium tetrachloride. This emulsifier has antistatic and anti - corrosive properties, can effectively prevent the lubricating oil composition from failing due to static electricity or corrosion during storage and use; at the same time, it also has strong bactericidal and antibacterial capabilities, can inhibit the growth of microorganisms, and extend the service life of the lubricating oil; in addition, the cerium element in the emulsifier is prone to undergo tribochemical reactions with the steel surface to generate cerium oxide, enhancing the tribological properties of the lubricating oil.

[0032] In some embodiments of the present application, the preparation method of the emulsifier didodecyldimethyl cerium tetrachloride includes the following steps:

[0033] (1) Mix an equimolar amount of dodecyl dimethyl ammonium chloride and cerium chloride in methanol and stir for 12 h;

[0034] (2) Put the mixture obtained in step (1) into a vacuum drying oven and vacuum dry it at 80 °C for 12 h to obtain a white solid powder, dodecyl dimethyl cerium tetrachloride.

[0035] In some embodiments of the present application, the compound containing a free amino functional group includes polylysine. Polylysine is a material with extremely high biocompatibility. Using polylysine as a component of the lubricating oil composition is not only safe and non-toxic but also has certain nutritional value and is suitable for fields such as food, cosmetics, and medicine. At the same time, polylysine contains a large number of free amino functional groups, which can enhance the adsorption of the lubricating oil composition to the interface.

[0036] In some embodiments of the present application, the molecular weight of the polylysine is 3500 - 5500, such as 3500, 4000, 4500, 5000, 5500, etc.

[0037] In some embodiments of the present application, the alcohol compound includes one or more of ethylene glycol, propylene glycol, glycerol, and butanediol.

[0038] In some embodiments of the present application, the alcohol compound includes ethylene glycol. Ethylene glycol has a hydroxyl functional group (-OH) and a low viscosity, is easily adsorbed to the friction interface, and has good lubricating performance. At the same time, ethylene glycol has a higher boiling point than water and is more difficult to volatilize, which can enhance the stability of the lubricating oil composition.

[0039] The embodiments of the present application also provide a preparation method of the lubricating oil composition described in the first aspect of the present application, including the following steps: Mix a hydrocarbon compound, an emulsifier, and an aqueous phase to obtain the lubricating oil composition.

[0040] In some embodiments of the present application, the mixing is ultrasonic mixing.

[0041] In some embodiments of the present application, the temperature of the mixing is 40 - 50 °C, such as 40 °C, 45 °C, 48 °C, 50 °C, etc., and the time of the mixing is 0.5 - 1 h, such as 0.5 h, 0.8 h, 0.9 h, 1 h, etc.

[0042] The embodiments of the present application also provide an application of the lubricating oil composition described in the first aspect of the present application or the lubricating oil composition obtained by the preparation method described in the second aspect of the present application in lubricating bearing steel. The lubricating oil composition of the present application has good aqueous-phase cooling and cleaning performance, can effectively remove the grinding debris and heat generated during the processing, and prevent the metal surface from getting hot and deformed. At the same time, it also maintains the lubricating performance of the oil phase, forms a stable oil film on the surface of the bearing steel, prevents the direct contact of the metal surface, significantly reduces the friction coefficient, and reduces wear. In addition, the formula design of the lubricating oil composition of the present application excludes irritating substances harmful to the human body, ensuring that it is harmless to the health of the operating workers during use. At the same time, its good anti-emulsification performance reduces the deterioration and waste of the lubricating oil caused by emulsification.

[0043] The technical solution of the present application will be further described below in conjunction with specific embodiments.

[0044] Example 1

[0045] A lubricating oil composition comprises the following raw materials in parts by weight: 0.5 part of octadecenoic acid, 0.5 part of dodecyldimethyl cerium tetrachloride (the emulsifier and the oil phase are in equal mass parts), and 99 parts of the aqueous phase; the aqueous phase comprises the following raw materials: 1 part of polylysine with a molecular weight of 4500, 4 parts of ethylene glycol, and 5 parts of water.

[0046] The preparation method of the lubricating oil composition described in Example 1 comprises the following steps: ultrasonically mixing a hydrocarbon compound, an emulsifier, and the aqueous phase at a temperature of 40 °C for 0.5 h to obtain the lubricating oil composition.

[0047] Example 2

[0048] The difference between the lubricating oil composition described in Example 2 and the lubricating oil composition described in Example 1 is only that: the weight part of the hydrocarbon compound in the lubricating oil composition described in Example 2 is 1 part.

[0049] The specific operation steps include:

[0050] A lubricating oil composition comprises the following raw materials in parts by weight: 1 part of octadecenoic acid, 1 part of dodecyldimethyl cerium tetrachloride, and 98 parts of the aqueous phase; the aqueous phase comprises the following raw materials: 1 part of polylysine with a molecular weight of 4500, 4 parts of ethylene glycol, and 5 parts of water.

[0051] The preparation method of the lubricating oil composition described in Example 2 comprises the following steps: ultrasonically mixing a hydrocarbon compound, an emulsifier, and the aqueous phase at a temperature of 40 °C for 0.5 h to obtain the lubricating oil composition.

[0052] Example 3

[0053] The lubricating oil composition described in Example 3 is different from the lubricating oil composition described in Example 1 only in that: the weight portion of the hydrocarbon compound in the lubricating oil composition described in Example 3 is 2 parts.

[0054] The specific operation steps include:

[0055] A lubricating oil composition comprises the following raw materials in parts by weight: 2 parts of octadecenoic acid, 2 parts of didodecyldimethyl cerium tetrachloride, and 96 parts of an aqueous phase; the aqueous phase comprises the following raw materials: 1 part of polylysine with a molecular weight of 4500, 4 parts of ethylene glycol, and 5 parts of water.

[0056] The preparation method of the lubricating oil composition described in Example 3 comprises the following steps: ultrasonically mixing the hydrocarbon compound, the emulsifier, and the aqueous phase at a temperature of 40°C for 0.5 h to obtain the lubricating oil composition.

[0057] Example 4

[0058] The lubricating oil composition described in Example 4 is different from the lubricating oil composition described in Example 1 only in that: the weight portion of the hydrocarbon compound in the lubricating oil composition described in Example 4 is 3 parts.

[0059] The specific operation steps include:

[0060] A lubricating oil composition comprises the following raw materials in parts by weight: 3 parts of octadecenoic acid, 3 parts of didodecyldimethyl cerium tetrachloride, and 94 parts of an aqueous phase; the aqueous phase comprises the following raw materials: 1 part of polylysine with a molecular weight of 4500, 5 parts of ethylene glycol, and 4 parts of water.

[0061] The preparation method of the lubricating oil composition described in Example 4 comprises the following steps: ultrasonically mixing the hydrocarbon compound, the emulsifier, and the aqueous phase at a temperature of 40°C for 0.5 h to obtain the lubricating oil composition.

[0062] Example 5

[0063] The difference between Example 5 and Example 1 is only that: octadecane is used instead of octadecenoic acid in the lubricating oil composition described in Example 5, and the remaining operation methods are the same as those in Example 1.

[0064] Example 6

[0065] The difference between Example 6 and Example 1 is only that: octadecene is used instead of octadecenoic acid in the lubricating oil composition described in Example 6, and the remaining operation methods are the same as those in Example 1.

[0066] Example 7

[0067] The difference between Example 7 and Example 1 is only that: octadecanoic acid is used instead of octadecenoic acid in the lubricating oil composition described in Example 7, and the remaining operation methods are the same as those in Example 1.

[0068] Example 8

[0069] The difference between Example 8 and Example 1 is only that: in the lubricating oil composition described in Example 8, polyglutamic acid is used instead of polylysine, and the remaining operation methods are the same as those in Example 1.

[0070] Example 9

[0071] The difference between Example 9 and Example 1 is only that: in the lubricating oil composition described in Example 9, polyaspartic acid containing a carboxyl group is used instead of polylysine, and the remaining operation methods are the same as those in Example 1.

[0072] Example 10

[0073] The difference between Example 10 and Example 1 is only that: in the lubricating oil composition described in Example 10, decenoic acid is used instead of octadecenoic acid, and the remaining operation methods are the same as those in Example 1.

[0074] Example 11

[0075] The difference between Example 11 and Example 1 is only that: in the lubricating oil composition described in Example 11, eicosenoic acid is used instead of octadecenoic acid, and the remaining operation methods are the same as those in Example 1.

[0076] Comparative Example 1

[0077] The difference between Comparative Example 1 and Example 1 is only that: the lubricating oil composition described in Comparative Example 1 only contains raw material hydrocarbon compounds and does not contain raw material emulsifiers and the aqueous phase.

[0078] Comparative Example 2

[0079] The difference between Comparative Example 2 and Example 1 is only that: the lubricating oil composition described in Comparative Example 2 only contains the raw material aqueous phase, and the remaining operations are the same as those in Example 1.

[0080] Comparative Example 3

[0081] The difference between Comparative Example 3 and Example 1 is only that: in the lubricating oil composition described in Comparative Example 3, Span 80 is used as the emulsifier instead of cerium dichloride dimethyldidodecyl, and the remaining operation methods are the same as those in Example 1.

[0082] Coefficient of friction Wear scar diameter (μm) Dynamic viscosity (m·Pa·s) Example 1 0.001 161 18.3 Example 2 0.002 172 18.9 Example 3 0.008 180 18.6 Example 4 0.012 198 19.1 Example 5 0.014 234 16.6 Example 6 0.009 228 16.4 Example 7 0.022 243 19.7 Example 8 0.048 265 - Example 9 0.074 201 - Example 10 0.006 194 17.4 Example 11 0.020 238 16.8 Comparative Example 1 0.06 152 33.4 Comparative Example 2 0.028 223 14.2 Comparative Example 3 0.031 241 - Comparative Example 4 0.012 205 - Comparative Example 5 0.086 181 -

[0083] It can be seen from Table 1 that: the viscosities of the lubricating oil compositions described in the present application are all between the aqueous phase and the oil phase.

[0084] When using the lubricating oil composition described in Example 1 of the present application to lubricate the bearing steel / bearing steel friction pair, the friction coefficient is

[0085] Comparative Example 4

[0086] The difference between Comparative Example 4 and Example 1 is only that: in the lubricating oil composition of Comparative Example 4, sodium dodecylbenzenesulfonate is used as an emulsifier instead of cerium dichloride bis(dodecyl dimethyl), and the remaining operation methods are the same as those in Example 1.

[0087] Comparative Example 5

[0088] The difference between Comparative Example 5 and Example 1 is only that: in the lubricating oil composition of Comparative Example 5, lysine is used instead of polylysine, and the remaining operation methods are the same as those in Example 1.

[0089] Performance study of the lubricating oil compositions described in Examples 1-11 of the present application and the lubricating oil compositions described in Comparative Examples 1-5:

[0090] The friction coefficients of the lubricating oils described in Examples 1-11 of the present application and Comparative Examples 1-5 were measured respectively. The test conditions were: a ball-on-disk rotational tribology test was carried out at room temperature, using a GCr15 bearing steel ball with a diameter of 6 mm and a GCr15 bearing disk. The rotational speed of the testing machine was 400 rpm, the rotational radius was 3 mm, the load was 4 N, and the test time was 30 minutes. The test results are shown in Table 1.

[0091] Table 10.001, while the friction coefficient of Comparative Example 1 using oil-phase lubrication was 0.06. The lubricating oil composition of the present application can reduce the friction coefficient by more than 95% compared with the single oil phase. The friction coefficient of Comparative Example 2 using water-phase lubrication was 0.028. In contrast, using the lubricating oil composition of Example 1 can reduce the friction coefficient by more than 90% and reduce the ball wear scar diameter.

[0092] Examples 2 to 4 are lubricating oil compositions prepared with different amounts of oil phase. It can be seen from the table that the friction coefficient is closely related to the proportion of the oil phase therein. Only when the proportion of the oil phase is 0.5-2% by weight can superlubricity be achieved.

[0093] In Examples 5-7, the oil phase in Example 1 was replaced with other hydrocarbon compounds with 18 carbon atoms. The results showed that the oil phase containing double bonds and carboxyl groups in Example 1 had the lowest friction coefficient and wear scar diameter, and the oil phase containing double bonds had lower friction coefficient and wear scar diameter than the one without double bonds, indicating that double bonds and carboxyl groups in the oil phase contribute to improving the lubrication performance.

[0094] In Examples 8 and 9, the amino acids in the water phase were replaced with other types of amino acids. The results showed that both the friction coefficient and the wear scar diameter increased, indicating that only polylysine has good lubrication effect as the water phase.

[0095] In Examples 10 and 11, the number of carbon atoms in the oil phase was reduced to 10 and increased to 22 respectively. The results showed that reducing the number of carbon atoms slightly weakened the lubricating performance, while increasing the number of carbon atoms deteriorated the lubricating effect. It can be predicted that the maximum number of carbon atoms in the oil phase is 18.

[0096] From Comparative Examples 1-5, the comparison between the aqueous phase and the oil phase alone, and the comparison of replacing the emulsifier can be seen. The results showed that the lubricating oil composition of the present application has better effects than the aqueous phase and the oil phase alone, and when the emulsifier is cerium dodecyl dimethyl tetrachloride, the effect is the best.

[0097] Although the above embodiments have been shown and described, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions, and variations made by those of ordinary skill in the art to the above embodiments are within the protection scope of the present invention.

Claims

1. A lubricating oil composition, characterized in that: The method comprises the following raw materials in parts by weight: 0.1-5 parts of hydrocarbon compound, 0.1-5 parts of emulsifier, and 90-99.8 parts of aqueous phase; The aqueous phase comprises the following raw materials: a compound containing free amino functional groups, an alcohol compound and water.

2. The lubricating oil composition according to claim 1, characterized in that The method comprises the following raw materials in parts by weight: 0.5-2 parts of hydrocarbon compound, 0.5-2 parts of emulsifier, and 96-99 parts of aqueous phase; The water phase comprises the following raw materials in parts by weight: 0.8-1.2 parts of a compound containing a free amino functional group, 3-5 parts of an alcohol compound and 4-6 parts of water.

3. The lubricating oil composition according to claim 1, characterized in that The hydrocarbon compound includes one or more of C1-C20 alkanes, C2-C20 alkenes, C1-C20 alkanoic acids and C2-C20 olefinic acids; Preferably, the hydrocarbon compound includes one or more of C3-C18 olefins and C3-C18 olefinic acids.

4. The lubricating oil composition according to claim 1, characterized in that The emulsifier includes didodecyldimethylcerium tetrachloride.

5. The lubricating oil composition according to claim 1, characterized in that: The compound containing free amino functional groups is polylysine; Preferably, the molecular weight of the polylysine is 3500-5500.

6. The lubricating oil composition according to claim 1, characterized in that: The alcohol compound includes one or more of ethylene glycol, propylene glycol, glycerol and butanediol.

7. The lubricating oil composition according to claim 1, characterized in that The alcohol compound includes ethylene glycol.

8. The method for preparing the lubricating oil composition according to any one of claims 1 to 7, characterized in that: The following steps are involved: The hydrocarbon compound, the emulsifier and water are mixed to obtain the lubricating oil composition.

9. The method for preparing the lubricating oil composition according to claim 8, characterized in that: The mixing is ultrasonic mixing; Preferably, the mixing temperature is 40-50° C., and the mixing time is 0.5-1 h.

10. Use of the lubricating oil composition according to any one of claims 1 to 7 or the lubricating oil composition obtained by the preparation method according to any one of claims 8 to 9 in lubricating bearing steel.