High-temperature-resistant environment-friendly lubricating oil and preparation method thereof

Abstract

The invention relates to the field of lubricating oil, and particularly discloses high-temperature-resistant environment-friendly lubricating oil and a preparation method thereof. The lubricating oil comprises the following components in parts by weight: 88-93 parts of base oil; 1 to 1.5 parts of an antioxidant; 0.1 to 0.5 part of a preservative; 1-3 parts of a viscosity index improver; 1-3 parts of an anti-wear agent; 1-1.5 parts of an extreme pressure additive; 0.3 to 0.6 part of an antirust agent; the base oil comprises epoxidized coconut oil, pentaerythritol ester and polyethylene glycol, and the weight part ratio of the epoxidized coconut oil to the pentaerythritol ester to the polyethylene glycol is 9: 3: 1. The preparation method comprises the following steps: mixing the base oil; and mixing the components. The lubricating oil provided by the invention has the advantages of excellent biodegradability and high temperature resistance.

Description

Technical Field

[0001] The present application relates to the field of lubricating oils, and more specifically, to a high temperature resistant and environmentally friendly lubricating oil and a preparation method thereof. Background Art

[0002] Lubricating oil is a liquid or semi-solid substance used to reduce friction, protect mechanical parts and extend their service life. It is usually composed of base oil and additives. Lubricating oil plays a vital role in various mechanical equipment, ranging from automobile engines to industrial machinery to household appliances.

[0003] Environmentally friendly lubricants, also known as bio-based lubricants or biodegradable lubricants, are lubricants with less impact on the environment. This type of lubricant is usually made from renewable resources, such as vegetable oil, and has good biodegradability and low ecotoxicity, but its antioxidant properties are poor and need to be improved by adding more additives. On the one hand, the increase in additives reduces the biodegradation rate of vegetable oils, and on the other hand, the increase in the amount of additives does not mean good compatibility with vegetable oils, so the performance of the lubricant is greatly reduced, especially for some environments with high temperature resistance requirements, the lubricant cannot meet the use requirements. Summary of the invention

[0004] In order to improve the biodegradability and high temperature resistance of lubricating oil, the present application provides a high temperature resistant and environmentally friendly lubricating oil and a preparation method thereof.

[0005] In the first aspect, the present application provides a high temperature resistant and environmentally friendly lubricating oil, which adopts the following technical solution:

[0006] A high temperature resistant and environmentally friendly lubricating oil comprises the following components in parts by weight:

[0007] Base oil 88-93 parts;

[0008] 1-1.5 parts of antioxidant;

[0009] Preservative 0.1-0.5 parts;

[0010] 1-3 parts of viscosity index improver;

[0011] 1-3 parts of antiwear agent;

[0012] 1-1.5 parts of extreme pressure additives;

[0013] Rust inhibitor 0.3-0.6 parts;

[0014] The base oil comprises epoxidized coconut oil, pentaerythritol ester and polyethylene glycol, and the weight ratio of the epoxidized coconut oil, pentaerythritol ester and polyethylene glycol is 9:3:1.

[0015] By adopting the above technical scheme, due to the use of the compounded base oil, in which epoxidized coconut oil is the main component of the base oil, the lubricating oil has excellent degradability. After compounding with pentaerythritol ester and polyethylene glycol, it is not necessary to add too many additives to improve the poor oxidation resistance of pure vegetable oil and maintain good degradability. The base oil is the main component of the lubricating oil. The compounding of this component can further improve the anti-oxidation performance and high temperature resistance of the lubricating oil while maintaining its excellent degradability.

[0016] Optionally, the preparation method of the epoxidized coconut oil is:

[0017] Coconut oil pretreatment: dry the coconut oil, add the catalyst formic acid into the dried coconut oil, stir thoroughly until it is uniform, and the amount of catalyst added is 1% of the weight of the coconut oil;

[0018] Epoxidation reaction: hydrogen peroxide was added dropwise to the coconut oil containing the catalyst, the amount of hydrogen peroxide added was 15% of the weight of the coconut oil, the temperature of the reaction system was controlled at 50°C, and stirring was continued for 8 hours until the reaction was complete;

[0019] Post-treatment: After the reaction is completed, stop heating and continue stirring for 1 hour to allow the reaction to proceed completely. Centrifuge, wash, and dry the reactants to remove impurities to obtain epoxidized coconut oil.

[0020] By adopting the above technical scheme, the epoxidized coconut oil prepared improves the problems of poor antioxidant and thermal stability of coconut oil, and makes the epoxidized coconut oil have good compatibility and is easier to be compounded and mixed with pentaerythritol ester and polyethylene glycol, thereby improving the biodegradability and high temperature resistance of the lubricating oil.

[0021] Optionally, the lubricating oil further comprises menthol microcapsules, silicon carbide and ethyl cellulose, wherein the weight portion of the menthol microcapsules is 1-2 parts, the weight portion of the silicon carbide is 1-2 parts, and the weight portion of the ethyl cellulose is 1.5-2 parts.

[0022] By adopting the above technical scheme, during the use of the lubricant, the heat generated by the high temperature environment and friction increases, and impurity precipitates are easily generated, which damages the membrane structure of the lubricant. On the one hand, ethyl cellulose can improve the agglomeration characteristics of silicon carbide, so that silicon carbide can be quickly dispersed to fill the cracks of the membrane structure and improve its wear resistance. On the other hand, ethyl cellulose adsorbs impurity precipitates through its microporous structure, which cleans the lubricant and reduces the secondary damage of impurity precipitates to the lubrication effect. Menthol microcapsules are made of menthol wrapped in capsule wall materials. When the capsule wall material is broken, menthol can be released. Menthol evaporates at high temperatures and absorbs heat, reducing heat, thereby reducing the effect of temperature on the lubricant. These three substances all have good biodegradability, and the combination of the three further improves the biodegradability and high temperature resistance of the lubricating oil.

[0023] Optionally, the preparation method of the menthol microcapsules is:

[0024] Prepare the oil phase: add menthol to ethyl acetate and stir until completely dissolved to form an oil phase;

[0025] Prepare the aqueous phase: add polyvinyl alcohol and gum arabic to water, the amount of polyvinyl alcohol added is 4 times the weight of menthol, the amount of gum arabic added is 2 times the weight of menthol, heat to 70°C, continue stirring until completely dissolved, cool to room temperature, add Tween 80, the amount of Tween 80 added is 40% of the weight of menthol, continue stirring until uniform, and form an aqueous phase;

[0026] Emulsification: Add the oil phase to the water phase with a volume ratio of 1:10, and stir continuously at 10,000 rpm for 20 min to form a stable emulsion;

[0027] Curing: Stir the emulsion at a speed of 5000 rpm for 1 hour, and cool it to room temperature to completely evaporate the ethyl acetate. Add glutaraldehyde, a crosslinking agent, to the emulsion in an amount of 0.5% of the total weight of polyvinyl alcohol and gum arabic. Continue stirring for 30 minutes to perform a crosslinking reaction to form microcapsules.

[0028] Separation, washing and drying: Under centrifugal conditions of 5000 rpm for 15 minutes, the microcapsules are separated from the emulsion, the microcapsules are washed to remove residual impurities, and the microcapsules are dried until constant weight is reached to obtain menthol microcapsules.

[0029] By adopting the above technical solution, the prepared menthol microcapsules have good dispersibility in the base oil.

[0030] Optionally, the particle size of the silicon carbide is 40-60 nm.

[0031] Optionally, the particle size of the menthol microcapsules is 20-50 μm.

[0032] In a second aspect, the present application provides a method for preparing a high temperature resistant and environmentally friendly lubricating oil, which adopts the following technical solution:

[0033] A method for preparing a high temperature resistant and environmentally friendly lubricating oil comprises the following steps:

[0034] Base oil mixing: preparing epoxidized coconut oil, taking epoxidized coconut oil, pentaerythritol ester and polyethylene glycol according to the ratio, preheating them to 55° C. respectively, and maintaining the temperature, mixing the epoxidized coconut oil, pentaerythritol ester and polyethylene glycol and stirring them until they are uniform, to obtain a mixed base oil;

[0035] Mix the components: maintain 55°C, add antioxidants, preservatives, viscosity index improvers, anti-wear agents, extreme pressure additives, and rust inhibitors to the base oil in sequence while stirring. After adding each component, stir thoroughly until the component is evenly dispersed in the base oil. After all the additives are added, continue stirring until all the components are completely evenly dispersed. Filter to obtain high-temperature resistant and environmentally friendly lubricating oil.

[0036] By adopting the above technical solution, through step-by-step dispersion and mixing, the additive and the base oil can be made well compatible, and the prepared lubricating oil has excellent performance.

[0037] In a third aspect, the present application provides a method for preparing a high temperature resistant and environmentally friendly lubricating oil, which adopts the following technical solution:

[0038] A method for preparing a high temperature resistant and environmentally friendly lubricating oil comprises the following steps:

[0039] Base oil mixing: preparing epoxidized coconut oil, taking epoxidized coconut oil, pentaerythritol ester and polyethylene glycol according to the ratio, preheating them to 55° C. respectively, and maintaining the temperature, mixing the epoxidized coconut oil, pentaerythritol ester and polyethylene glycol and stirring them until they are uniform, to obtain a mixed base oil;

[0040] Mixing high temperature resistant components: preparing menthol microcapsules, taking menthol microcapsules, silicon carbide and ethyl cellulose according to the proportion, stirring and mixing until uniform, and preparing a high temperature resistant component mixture for standby use;

[0041] Mixing of components: Maintaining 55°C, add antioxidant, preservative, viscosity index improver, high temperature resistant component mixture, antiwear agent, extreme pressure additive and rust inhibitor to the base oil in sequence while stirring. After adding each component, stir thoroughly until the component is evenly dispersed in the base oil. After all the additives are added, continue stirring until all the components are completely evenly dispersed. Filter to obtain high temperature resistant and environmentally friendly lubricating oil.

[0042] In summary, this application has the following beneficial effects:

[0043] 1. Since the present application adopts epoxidized coconut oil, pentaerythritol ester and polyethylene glycol to prepare the base oil, the base oil can maintain excellent biodegradability and improve the poor oxidation resistance of pure vegetable oil, thereby improving the oxidation resistance and high temperature resistance of the lubricating oil.

[0044] 2. In the present application, menthol microcapsules, silicon carbide and ethyl cellulose are preferably used, because all three have good biodegradability and will not affect the biodegradability of the lubricant. Moreover, the menthol microcapsules can evaporate and absorb heat after rupture, thereby reducing the effect of low temperature on the lubricant. The impurity precipitates are adsorbed by ethyl cellulose, and the cracks in the lubricant film structure are filled by silicon carbide to improve its wear resistance. The combination of the three further improves the high temperature resistance of the lubricant.

[0045] 3. The method of the present application, through step-by-step dispersion and mixing, the components of the lubricating oil obtained have good compatibility and greatly improved performance. DETAILED DESCRIPTION

[0046] The present application is further described in detail with reference to the following examples. It is specially noted that if no specific conditions are specified in the following examples, the conventional conditions or the conditions recommended by the manufacturer are followed, and the raw materials used in the following examples can be obtained from common commercial sources unless otherwise specified.

[0047] Coconut oil is refined coconut oil purchased from Zhongfu Oil Group.

[0048] Pentaerythritol ester: the following examples and comparative examples all use pentaerythritol tetralaurate, a superior grade product, CAS No.: 13057-50-6, brand: KMIK.

[0049] Polyethylene glycol, industrial grade, premium grade, molecular weight 4000.

[0050] Antioxidants: Green tea extract and tea polyphenols are used in the following examples and comparative examples.

[0051] Preservative: DL604 Kasong Kasong preservative is used in the following examples and comparative examples.

[0052] Viscosity index improver: the following examples and comparative examples all use ethylene-propylene copolymer OCP, model: T612, a superior grade product.

[0053] As anti-wear agent, potassium salt of alkyl phosphate is used in the following examples and comparative examples.

[0054] As an extreme pressure additive, the following examples and comparative examples all use di-n-butyl phosphite, CAS No.: 1809-19-4.

[0055] As a rust inhibitor, diethanolamine is used in the following examples and comparative examples.

[0056] Menthol, CAS number: 2216-51-5.

[0057] Silicon carbide, powder, nanoscale.

[0058] Ethyl cellulose, CAS No.: 9004-57-3, pharmaceutical grade.

[0059] Example of base oil preparation

[0060] Preparation Example 1

[0061] The base oil comprises epoxidized coconut oil, pentaerythritol ester and polyethylene glycol, and the weight ratio of epoxidized coconut oil, pentaerythritol ester and polyethylene glycol is 9:3:1.

[0062] The preparation method of base oil is:

[0063] Preparation of epoxidized coconut oil:

[0064] Coconut oil pretreatment: Dry the coconut oil, heat the coconut oil at 90°C to remove moisture, add the catalyst formic acid into the dried coconut oil, stir it thoroughly until it is uniform, and the added amount of the catalyst is 1% of the weight of the coconut oil.

[0065] Epoxidation reaction: hydrogen peroxide was added dropwise to the coconut oil containing the catalyst, the amount of hydrogen peroxide added was 15% of the weight of the coconut oil, the temperature of the reaction system was controlled at 50°C, and stirring was continued for 8 hours until the reaction was complete.

[0066] Post-treatment: After the reaction is completed, stop heating and continue stirring for 1 hour to allow the reaction to proceed completely, centrifuge the reactants to remove the catalyst, wash the reactants to remove the residual catalyst and by-products, centrifuge the reactants again to remove moisture, dry the reactants, and heat to 90°C under vacuum conditions to remove residual moisture to obtain epoxidized coconut oil.

[0067] According to the ratio, 90 kg of epoxidized coconut oil, 30 kg of pentaerythritol ester and 10 kg of polyethylene glycol are taken, preheated to 55° C. respectively, and the temperature is maintained, and the epoxidized coconut oil, pentaerythritol ester and polyethylene glycol are mixed and stirred until uniform to obtain a mixed base oil.

[0068] Preparation Example 2

[0069] The difference between this preparation example and preparation example 1 is that the base oil in this preparation example is coconut oil.

[0070] Preparation Example 3

[0071] The difference between this preparation example and preparation example 1 is that coconut oil is used instead of epoxidized coconut oil in this preparation example.

[0072] Preparation Example 4

[0073] The difference between this preparation example and preparation example 1 is that there is no pentaerythritol ester in this preparation example.

[0074] Preparation Example 5

[0075] The difference between this preparation example and preparation example 1 is that there is no polyethylene glycol in this preparation example.

[0076] Preparation Example 6

[0077] The difference between this preparation example and preparation example 1 is that pentaerythritol ester and polyethylene glycol are not contained in this preparation example.

[0078] Example

[0079] Example 1

[0080] A high temperature resistant and environmentally friendly lubricating oil, comprising the following components:

[0081] 88kg base oil; 1kg antioxidant; 0.1kg preservative; 1kg viscosity index improver; 1kg antiwear agent; 1kg extreme pressure additive; 0.3kg rust inhibitor.

[0082] The base oil comprises epoxidized coconut oil, pentaerythritol ester and polyethylene glycol, the weight ratio of epoxidized coconut oil, pentaerythritol ester and polyethylene glycol is 9:3:1, and is prepared by Preparation Example 1.

[0083] A method for preparing a high temperature resistant and environmentally friendly lubricating oil comprises the following steps:

[0084] (1) Base oil mixing: Take the base oil prepared in Preparation Example 1 according to the mixing ratio.

[0085] (2) Mixing the components: Maintaining the temperature at 55°C, take the components according to the above ratios, and add antioxidants, preservatives, viscosity index improvers, anti-wear agents, extreme pressure additives, and rust inhibitors to the base oil in sequence while stirring. After each component is added, stir thoroughly until the component is evenly dispersed in the base oil. After all the additives are added, continue stirring until all the components are completely evenly dispersed. Filter to obtain a high-temperature resistant and environmentally friendly lubricant.

[0086] Example 2

[0087] The difference between this embodiment and embodiment 1 is that the dosage of each component is different, see Table 1 for details.

[0088] Example 3

[0089] The difference between this embodiment and embodiment 1 is that the dosage of each component is different, see Table 1 for details.

[0090] Example 4

[0091] The difference between this embodiment and embodiment 2 is that the lubricating oil further includes 1 kg of menthol microcapsules, 1 kg of silicon carbide and 1.5 kg of ethyl cellulose, the particle size of the silicon carbide is 40 nm, the particle size of the menthol microcapsules is 20 μm, and the amount of each component is shown in Table 1.

[0092] A method for preparing a high temperature resistant and environmentally friendly lubricating oil comprises the following steps:

[0093] (1) Base oil mixing: Take the base oil prepared in Preparation Example 1 according to the mixing ratio.

[0094] (2) Mixing of high temperature resistant components:

[0095] 1) Preparation of menthol microcapsules:

[0096] Preparation of oil phase: Add 2 kg of menthol into ethyl acetate and stir until completely dissolved to form an oil phase.

[0097] Prepare the aqueous phase: add polyvinyl alcohol and gum arabic to water, the amount of polyvinyl alcohol added is 4 times the weight of menthol, and the amount of gum arabic added is 2 times the weight of menthol, heat to 70°C, continue stirring until completely dissolved, cool to room temperature, add Tween 80, the amount of Tween 80 added is 40% of the weight of menthol, continue stirring until uniform, and form an aqueous phase.

[0098] Emulsification: Add the oil phase to the water phase with a volume ratio of 1:10, and stir continuously at 10,000 rpm for 20 min to form a stable emulsion.

[0099] Curing: Stir the emulsion at a speed of 5000 rpm for 1 hour, and cool it to room temperature to completely evaporate the ethyl acetate. Add the crosslinking agent glutaraldehyde to the emulsion. The amount of glutaraldehyde added is 0.5% of the total weight of polyvinyl alcohol and gum arabic. Continue stirring for 30 minutes to perform a crosslinking reaction to form microcapsules.

[0100] Separation, washing and drying: Under centrifugal conditions of 5000 rpm for 15 minutes, the microcapsules are separated from the emulsion, the microcapsules are washed to remove residual impurities, and the microcapsules are dried until constant weight is reached to obtain menthol microcapsules.

[0101] 2) Take menthol microcapsules, silicon carbide and ethyl cellulose according to the ratio and stir and mix them until they are uniform to prepare a high temperature resistant component mixture for later use.

[0102] (3) Mixing the components: Maintaining the temperature at 55°C, add antioxidants, preservatives, viscosity index improvers, high temperature resistant component mixtures, anti-wear agents, extreme pressure additives, and rust inhibitors to the base oil in sequence while stirring. After each component is added, stir thoroughly until the component is evenly dispersed in the base oil. After all the additives are added, continue stirring until all the components are completely evenly dispersed. Filter to obtain a high temperature resistant and environmentally friendly lubricant.

[0103] Example 5

[0104] The difference between this embodiment and embodiment 4 is that the amounts of menthol microcapsules, silicon carbide and ethyl cellulose are different, and the amounts of each component are shown in Table 1. The particle size of silicon carbide is 50 nm, and the particle size of menthol microcapsules is 30 μm.

[0105] Example 6

[0106] The difference between this embodiment and embodiment 4 is that the dosage of menthol microcapsules, silicon carbide and ethyl cellulose is different, and the dosage of each component is shown in Table 1. The particle size of silicon carbide is 60 nm, and the particle size of menthol microcapsules is 50 μm.

[0107] Example 7

[0108] The difference between this embodiment and embodiment 5 is that the particle size of silicon carbide is 10 nm.

[0109] Example 8

[0110] The difference between this embodiment and embodiment 5 is that the particle size of silicon carbide is 100 nm.

[0111] Example 9

[0112] The difference between this embodiment and embodiment 5 is that the particle size of the menthol microcapsules is 10 μm.

[0113] Example 10

[0114] The difference between this embodiment and embodiment 5 is that the particle size of the menthol microcapsules is 80 μm.

[0115] Embodiment 11

[0116] The difference between this embodiment and embodiment 5 is that menthol is not prepared into microcapsules, but is directly added into the lubricating oil to replace the menthol microcapsules.

[0117] Example 12

[0118] The difference between this embodiment and embodiment 5 is that there are no menthol microcapsules in this embodiment.

[0119] Example 13

[0120] The difference between this embodiment and embodiment 5 is that there is no ethyl cellulose in this embodiment.

[0121] Embodiment 14

[0122] The difference between this embodiment and embodiment 5 is that there is no silicon carbide in this embodiment.

[0123] Embodiment 15

[0124] The difference between this embodiment and embodiment 5 is that there are no menthol microcapsules and silicon carbide in this embodiment.

[0125] Example 16

[0126] The difference between this embodiment and embodiment 5 is that there are no menthol microcapsules and ethyl cellulose in this embodiment.

[0127] Embodiment 17

[0128] The difference between this embodiment and embodiment 5 is that there is no silicon carbide and ethyl cellulose in this embodiment.

[0129] Comparative Example

[0130] Comparative Example 1

[0131] The difference between this comparative example and Example 2 is that the base oil is prepared by Preparation Example 2.

[0132] Comparative Example 2

[0133] The difference between this comparative example and Example 2 is that the base oil is prepared by Preparation Example 3.

[0134] Comparative Example 3

[0135] The difference between this comparative example and Example 2 is that the base oil is prepared by Preparation Example 4.

[0136] Comparative Example 4

[0137] The difference between this comparative example and Example 2 is that the base oil is prepared by Preparation Example 5.

[0138] Comparative Example 5

[0139] The difference between this comparative example and Example 2 is that the base oil is prepared by Preparation Example 6.

[0140] Table 1 Amount and specifications of each component of lubricating oil

[0141]

[0142]

[0143] Performance testing

[0144] Detection Methods

[0145] 1. Biodegradability: The lubricating oils prepared in the examples and comparative examples were selected as samples and tested according to CEC L-33-A-93. The biodegradability test results are shown in Table 2.

[0146] 2. Dispersion stability: The lubricating oils prepared in the examples and comparative examples were selected as samples, placed in an oven at 100° C. for 15 days, and then taken out and observed with the naked eye to see if any precipitation occurred. The test results are detailed in Table 2.

[0147] 3. Antioxidation: The lubricating oils prepared in the examples and comparative examples were selected as samples and tested with reference to “SH / T0193-2008 Determination of oxidation stability of lubricating oils - Rotating oxygen bomb method”. The oxidation stability test results are detailed in Table 2.

[0148] 4. High temperature resistance: The lubricating oils prepared in the embodiments and comparative examples were selected as samples and measured with reference to "SH / T0680-1999 Method for Determination of Thermal Stability of Heat Transfer Fluids". The thermal stability is expressed as the deterioration rate. The smaller the deterioration rate, the better the thermal stability. The test results are detailed in Table 2.

[0149] 5. Wear resistance: The lubricating oils prepared in each embodiment and comparative example were selected as samples. The samples at room temperature were taken as one group, and the samples after heating at 200°C for 200 hours were taken as one group. The two groups of samples were measured separately according to the "GB / T3142-2019 Determination of load-bearing capacity of lubricants - four-ball method". The maximum no-seizure load test results are shown in Table 2.

[0150] Table 2 Test results of various embodiments and comparative examples

[0151]

[0152]

[0153] Combining Example 2 and Comparative Example 1 with Table 2, it can be seen that the base oil used in the present application is compounded with epoxidized coconut oil, pentaerythritol ester and polyethylene glycol to obtain a lubricating oil with excellent biodegradability and high temperature resistance, and can be widely used in high temperature environments. In addition, combining Example 2 with Comparative Examples 1 to Comparative Examples 5 with Table 2, it can be seen that only when epoxidized coconut oil, pentaerythritol ester and polyethylene glycol are compounded, the effect can be optimally exerted, and the biodegradability and high temperature resistance of the lubricating oil are greatly improved.

[0154] Combining Example 2 and Example 5 with Table 2, it can be seen that after adding menthol microcapsules, silicon carbide and ethyl cellulose to the lubricating oil component, the biodegradability is slightly improved, and the high temperature resistance is further greatly improved. And combining Example 2 and Example 11-Example 17 with Table 2, it can be seen that only when these three substances are used in combination, the effect of improving the high temperature resistance is optimal.

[0155] It can be seen from Example 5 and Example 7 to Example 10 and Table 2 that limiting the particle size of silicon carbide and menthol microcapsules can improve the high temperature resistance of the lubricating oil to a certain extent.

[0156] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A high temperature resistant and environmentally friendly lubricating oil, characterized in that: The composition comprises the following components in parts by weight: Base oil 88-93 parts; 1-1.5 parts of antioxidant; Preservative 0.1-0.5 parts; 1-3 parts of viscosity index improver; 1-3 parts of antiwear agent; 1-1.5 parts of extreme pressure additives; Rust inhibitor 0.3-0.6 parts; The base oil comprises epoxidized coconut oil, pentaerythritol ester and polyethylene glycol, and the weight ratio of the epoxidized coconut oil, pentaerythritol ester and polyethylene glycol is 9:3:

1.

2. A high temperature resistant and environmentally friendly lubricating oil according to claim 1, characterized in that: The preparation method of the epoxidized coconut oil is: Coconut oil pretreatment: dry the coconut oil, add the catalyst formic acid into the dried coconut oil, stir thoroughly until it is uniform, and the amount of catalyst added is 1% of the weight of the coconut oil; Epoxidation reaction: hydrogen peroxide was added dropwise to the coconut oil containing the catalyst, the amount of hydrogen peroxide added was 15% of the weight of the coconut oil, the temperature of the reaction system was controlled at 50°C, and stirring was continued for 8 hours until the reaction was complete; Post-treatment: After the reaction is completed, stop heating and continue stirring for 1 hour to allow the reaction to proceed completely. Centrifuge, wash, and dry the reactants to remove impurities to obtain epoxidized coconut oil.

3. The high temperature resistant and environmentally friendly lubricating oil according to claim 1, characterized in that: The lubricating oil further comprises menthol microcapsules, silicon carbide and ethyl cellulose. The weight portion of the menthol microcapsules is 1-2 parts, the weight portion of the silicon carbide is 1-2 parts, and the weight portion of the ethyl cellulose is 1.5-2 parts.

4. The high temperature resistant and environmentally friendly lubricating oil according to claim 3, characterized in that: The preparation method of the menthol microcapsule is: Prepare the oil phase: add menthol to ethyl acetate and stir until completely dissolved to form an oil phase; Prepare the aqueous phase: add polyvinyl alcohol and gum arabic to water, the amount of polyvinyl alcohol added is 4 times the weight of menthol, the amount of gum arabic added is 2 times the weight of menthol, heat to 70°C, continue stirring until completely dissolved, cool to room temperature, add Tween 80, the amount of Tween 80 added is 40% of the weight of menthol, continue stirring until uniform, and form an aqueous phase; Emulsification: Add the oil phase to the water phase with a volume ratio of 1:10, and stir continuously at 10,000 rpm for 20 min to form a stable emulsion; Curing: Stir the emulsion at a speed of 5000 rpm for 1 hour, and cool it to room temperature to completely evaporate the ethyl acetate. Add glutaraldehyde, a crosslinking agent, to the emulsion in an amount of 0.5% of the total weight of polyvinyl alcohol and gum arabic. Continue stirring for 30 minutes to perform a crosslinking reaction to form microcapsules. Separation, washing and drying: Under centrifugal conditions of 5000 rpm for 15 minutes, the microcapsules are separated from the emulsion, the microcapsules are washed to remove residual impurities, and the microcapsules are dried until constant weight is reached to obtain menthol microcapsules.

5. The high temperature resistant and environmentally friendly lubricating oil according to claim 3, characterized in that: The particle size of the silicon carbide is 40-60 nm.

6. The high temperature resistant and environmentally friendly lubricating oil according to claim 4, characterized in that: The particle size of the menthol microcapsule is 20-50 μm.

7. The method for preparing a high temperature resistant and environmentally friendly lubricating oil according to any one of claims 1 to 2, characterized in that: The following steps are involved: Base oil mixing: preparing epoxidized coconut oil, taking epoxidized coconut oil, pentaerythritol ester and polyethylene glycol according to the ratio, preheating them to 55° C. respectively, and maintaining the temperature, mixing the epoxidized coconut oil, pentaerythritol ester and polyethylene glycol and stirring them until they are uniform, to obtain a mixed base oil; Mix the components: maintain 55°C, add antioxidants, preservatives, viscosity index improvers, anti-wear agents, extreme pressure additives, and rust inhibitors to the base oil in sequence while stirring. After adding each component, stir thoroughly until the component is evenly dispersed in the base oil. After all the additives are added, continue stirring until all the components are completely evenly dispersed. Filter to obtain high-temperature resistant and environmentally friendly lubricating oil.

8. The method for preparing a high temperature resistant and environmentally friendly lubricating oil according to any one of claims 4 to 6, characterized in that: The following steps are involved: Base oil mixing: preparing epoxidized coconut oil, taking epoxidized coconut oil, pentaerythritol ester and polyethylene glycol according to the ratio, preheating them to 55° C. respectively, and maintaining the temperature, mixing the epoxidized coconut oil, pentaerythritol ester and polyethylene glycol and stirring them until they are uniform, to obtain a mixed base oil; Mixing high temperature resistant components: preparing menthol microcapsules, taking menthol microcapsules, silicon carbide and ethyl cellulose according to the proportion, stirring and mixing until uniform, and preparing a high temperature resistant component mixture for standby use; Mixing of components: Maintaining 55°C, add antioxidant, preservative, viscosity index improver, high temperature resistant component mixture, antiwear agent, extreme pressure additive and rust inhibitor to the base oil in sequence while stirring. After adding each component, stir thoroughly until the component is evenly dispersed in the base oil. After all the additives are added, continue stirring until all the components are completely evenly dispersed. Filter to obtain high temperature resistant and environmentally friendly lubricating oil.

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