Composite Additive for Gearbox Oil of Pure Electric Vehicles and Its Preparation Method

Abstract

This invention belongs to the field of lubricating oil additive technology, specifically relating to a composite additive for pure electric vehicle gearbox oil and its preparation method. By mass percentage, it comprises the following components: 8-12% antioxidant, 10-15% friction index improver, 0.1-0.5% antifoaming agent, 70-78% anti-wear agent, and 2-5% rust inhibitor. The antioxidant is aminosiloxane-modified phenylphenothiazine, and the antifoaming agent is perfluorocyclobutyl aryl ether silicone oil. In this invention, in the aminosiloxane-modified phenylphenothiazine, a benzene ring is attached to the N- group of phenothiazine, reducing the polarity of phenothiazine. Furthermore, the siloxane segments can isolate the polar sulfoxide products generated after the oxidation of phenylphenothiazine. The flexible structure of the siloxane chain can encapsulate the active groups of phenothiazine, reducing side reactions with metal ions and decreasing sludge formation. Additionally, the amino group in the aminosiloxane-modified phenylphenothiazine can neutralize acidic oxidation products, reducing metal saponification reactions and further reducing sludge formation.

Description

Technical Field

[0001] This invention belongs to the field of lubricating oil additive technology, specifically relating to a composite additive for pure electric vehicle gearbox oil and its preparation method. Background Technology

[0002] Battery electric vehicles (BEVs) rely solely on batteries and motors for power and primarily consist of a chassis, body, battery, motor, electrical equipment, and various auxiliary systems. They achieve zero emissions during operation and represent the ultimate goal of new energy vehicle development.

[0003] As electric motors develop towards higher power and higher torque, the electric drive system of pure electric vehicles generates a lot of heat during operation. This is especially true for oil-cooled motor gearboxes, which face more demanding operating conditions. The increased load on the oil also places higher demands on the oil's oxidation resistance and anti-foaming properties.

[0004] Phenothiazine, as an antioxidant added to gearbox oil, has a good effect on inhibiting the growth of gearbox oil viscosity and acid value and prolonging oxidation induction. However, phenothiazine is prone to causing sludge in gearbox oil, especially when used as an antioxidant in hydrotreated base oil. The higher saturated hydrocarbon content of hydrotreated base oil leads to more serious sludge formation. Summary of the Invention

[0005] The purpose of this invention is to provide a composite additive for gearbox oil in pure electric vehicles and its preparation method, so as to solve the above-mentioned technical problems.

[0006] To achieve the above-mentioned technical objectives, the technical solution of the present invention is as follows:

[0007] A composite additive for gearbox oil in pure electric vehicles, comprising the following components by mass percentage: 8-12% antioxidant, 10-15% friction index improver, 0.1-0.5% antifoaming agent, 70-78% antiwear agent, and 2-5% rust inhibitor;

[0008] The antioxidant is aminosiloxane-modified phenylphenthiazine, and the antifoaming agent is perfluorocyclobutyl aryl ether silicone oil.

[0009] As a further improvement, the anti-wear agent comprises thiophosphite amine salt, phosphate ester, phosphonate ester and thiophosphate ester in a mass ratio of 4:6:5:1; the rust inhibitor is benzotriazole; and the friction index improver is phosphate ester or sulfurized fatty acid amine salt.

[0010] As a further improvement, by weight percentage, it includes the following components: 10% antioxidant, 12% friction index improver, 0.3% antifoaming agent, 74.7% anti-wear agent and 3% rust inhibitor.

[0011] This invention also provides a method for preparing a composite additive for gearbox oil in pure electric vehicles, comprising the following steps:

[0012] S1. Under nitrogen protection, toluene, bromophenylphenthiazide, and 3-aminopropyltriethoxysilane were mixed, and the catalysts tridibenzylacetone dipalladium and 4,5-bisdiphenylphosphine-9,9-dimethyloxanthracene were added. Potassium tert-butoxide was added at the same time, and the mixture was reacted at 80-85℃ for 4-6 h. After the reaction was completed, the mixture was cooled and filtered. The filter residue was washed with ethyl acetate, and then purified by vacuum distillation at 6.7 kPa and 30℃ using an alkaline alumina chromatography column to obtain aminosiloxane-modified phenylphenthiazide.

[0013] S2. Aryltrifluorovinyl ether silane was prepared by Grignard reaction using dimethyldimethoxysilane and 1-bromo-4-((1,2,2-trifluorovinyl)oxy)benzene as raw materials.

[0014] Under argon protection, perfluorocyclobutylaryl ether silane was prepared by thermal cyclization reaction using aryltrifluorovinyl ether silane as a raw material.

[0015] Under argon protection, using anhydrous acetic acid as solvent, perfluorocyclobutylaryl ether silane and dimethyldiethoxysilane as raw materials, the reaction was carried out at 90~95℃ for 24h. After the reaction was completed, the mixture was cooled to room temperature, acetic acid was removed by rotary evaporation, and perfluorocyclobutylaryl ether silicone oil was obtained by vacuum distillation.

[0016] S3. Add aminosiloxane-modified phenylphenthiazide, perfluorocyclobutyl aryl ether silicone oil, friction index improver, anti-wear agent and rust inhibitor to the reaction vessel in sequence, stir at 300~400 r / min for 40~60 min, and let stand for 40~60 min after mixing to obtain pure electric vehicle gearbox oil composite additive.

[0017] As a further improvement, in step S1, the preparation method of the bromophenylphenthiazide is as follows: dissolve phenylphenthiazide in tetrahydrofuran, add N-bromosuccinamide to it under ice-water bath conditions at 5°C, control the reaction temperature at 3~5°C, react for 6~8 hours, then pour the reaction solution into water and stir to precipitate solid, filter, wash the filter cake with distilled water, and dry the filter cake to obtain bromophenylphenthiazide.

[0018] As a further improvement, the preparation method of the phenylphenothiazine is as follows: phenothiazine, copper powder, potassium carbonate and iodobenzene are added to chlorobenzene, heated to 190~195℃ and reacted for 10h. After the reaction is completed, the temperature is lowered to room temperature, and then heated to 195℃ again for distillation to remove the remaining iodobenzene. After cooling to room temperature again, anhydrous ethanol is added, the temperature is raised to 70℃ and stirred for 10min, and then filtered immediately. The filtrate is collected and crystallized at room temperature. The precipitate is collected by filtration and dried to obtain phenylphenothiazine.

[0019] As a further improvement, in step S1, the molar ratio of bromophenylphenthiazine, 3-aminopropyltriethoxysilane, tridibenzylacetone dipalladium, 4,5-bis(diphenylphosphine-9,9-dimethyloxanthracene) and potassium tert-butoxide is 1:3:0.025:0.03~0.04:1.4, and the eluent in the chromatography column separation and purification process is a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 1:1.

[0020] As a further improvement, in step S2, the molar ratio of the perfluorocyclobutylaryl ether silane and the dimethyldiethoxysilane is 1:1.

[0021] As a further improvement, the molar ratio of the phenylphenthiazide to the N-bromosuccinamide is 3:2.5~2.8.

[0022] As a further improvement, the molar ratio of phenothiazine, iodobenzene, copper powder and potassium carbonate is 1:2.1:0.73~0.8:3.23~3.26.

[0023] Due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows:

[0024] This invention provides a composite additive for gearbox oil in pure electric vehicles and its preparation method. In the aminosiloxane-modified phenylphenothiazine, a benzene ring is attached to the N-terminus of the phenothiazine to reduce its polarity. Furthermore, the siloxane segments can isolate the polar sulfoxide products generated after the oxidation of phenylphenothiazine. The flexible structure of the siloxane chain can encapsulate the active groups of phenothiazine, reducing its side reactions with metal ions and reducing the formation of sludge. In addition, the amino group in the aminosiloxane-modified phenylphenothiazine can neutralize acidic oxidation products, reduce metal saponification reactions, and further reduce the formation of sludge.

[0025] Aminosiloxane-modified phenylphenothiazine, as an antioxidant, contains multiple secondary amine groups that can scavenge free radicals generated by base oils. At the same time, the sulfur in aminosiloxane-modified phenylphenothiazine acts as a peroxide decomposer, which can remove peroxides generated by the oxidation of base oils. It does not require the combination of free radical scavengers and peroxide decomposers, resulting in better antioxidant effects.

[0026] In this invention, perfluorocyclobutyl aryl ether silicone oil is used as an antifoaming agent. The presence of aryl groups improves the mechanical properties and thermal stability of the silicone oil, ensuring that it remains in a droplet state in the base oil and preventing the high-speed gear agitation from disrupting its droplet state and causing it to lose its defoaming effect.

[0027] The presence of the perfluorocyclobutyl structure can improve the electrical insulation of silicone oil, meeting the requirements of pure electric vehicles. At the same time, the close arrangement of fluorine atoms in the perfluorocyclobutyl structure can further reduce the surface tension of silicone oil and improve the defoaming effect.

[0028] In this invention, a compound of thiophosphite amine salt, phosphate ester, phosphonate ester and thiophosphate ester is used as an anti-wear agent, which has a better anti-wear effect. Attached Figure Description

[0029] Figure 1 The results show the antioxidant properties of the composite additives prepared in Example 1 and Comparative Examples 1-3 on gearbox oil;

[0030] Figure 2 The results are the test results of the composite additives of Example 1 and Comparative Examples 1-3 on the sludge production performance of gearbox oil.

[0031] Figure 3 These are the test results of the composite additives of Example 1 and Comparative Examples 1-3 on the insulation performance of gearbox oil. Detailed Implementation

[0032] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0033] In this invention, phenothiazine, iodobenzene, chlorobenzene, N-bromosuccinamide, tris(dibenzylacetone)palladium, and dimethyldimethoxysilane were purchased from Adamas-beta; potassium carbonate, copper powder, and tetrahydrofuran were purchased from General Reagent; 4,5-bis(diphenylphosphine-9,9-dimethyloxanthracene) were purchased from Zhejiang Metallurgical Research Institute; and 1-bromo-4-((1,2,2-trifluorovinyl)oxy)benzene was purchased from Hubei Rishengchang New Material Technology Co., Ltd.

[0034] Example 1 A composite additive for gearbox oil in pure electric vehicles, comprising the following components by mass percentage: 10% antioxidant aminosiloxane-modified phenylphenthiazide, 12% friction index improver sulfurized fatty acid amine salt, 0.3% antifoaming agent perfluorocyclobutyl aryl ether silicone oil, 74.7% antiwear agent and 3% rust inhibitor benzotriazole, wherein the antiwear agent includes thiophosphite amine salt, phosphate ester, phosphonate ester and thiophosphate ester, and the mass ratio of thiophosphite amine salt, phosphate ester, phosphonate ester and thiophosphate ester is 4:6:5:1.

[0035] This embodiment also provides a method for preparing the above-mentioned composite additive for pure electric vehicle gearbox oil, specifically including the following steps:

[0036] S1. Take 1 mol of phenothiazine, 0.73 mol of copper powder, 3.23 mol of potassium carbonate and 2.1 mol of iodobenzene, add them to 300 mL of chlorobenzene, heat to 190 °C and react for 10 h. After the reaction is complete, cool to room temperature, then heat to 195 °C and distill to remove the remaining iodobenzene. After cooling to room temperature again, add 300 mL of anhydrous ethanol, heat to 70 °C and stir for 10 min, then filter immediately. Collect the filtrate and crystallize at room temperature. Filter and collect the precipitate and dry at 60 °C to obtain phenylphenothiazine.

[0037] The specific equation is as follows:

[0038] ;

[0039] S2. Dissolve 3 mol of phenylphenthiazide in 20 mL of tetrahydrofuran, add 2.5 mol of N-bromosuccinamide in an ice-water bath at 5 °C, control the reaction temperature at 5 °C, react for 6 h, then pour the reaction solution into water and stir to precipitate solid. After filtration, wash the filter cake with distilled water and dry the filter cake at 80 °C to obtain bromophenylphenthiazide.

[0040] The specific equation is as follows:

[0041] ;

[0042] S3. Under nitrogen protection, 6 mL of toluene, 1 mol of bromophenylphenthiazide, and 3 mol of 3-aminopropyltriethoxysilane were mixed. 0.025 mol of tridibenzylacetone dipalladium and 0.03 mol of 4,5-bis(diphenylphosphine-9,9-dimethyloxanthracene) catalyst were added, along with 1.4 mol of potassium tert-butoxide. The mixture was reacted at 80 °C for 6 h. After the reaction was completed, the mixture was cooled and filtered. The resulting residue was washed three times with ethyl acetate, then distilled under reduced pressure at 6.7 kPa and 30 °C. The residue was then purified by alkaline alumina chromatography to obtain aminosiloxane-modified phenylphenthiazide. The chromatography purification used a 1:1 volume ratio of petroleum ether and ethyl acetate as the eluent.

[0043] The specific equation is as follows:

[0044] ,

[0045] Where R1 is ;

[0046] S4. Under argon protection, 0.8 mol magnesium powder, 0.49 mol dimethyldimethoxysilane and 180 mL tetrahydrofuran were mixed. Then, a mixed solution of 0.16 mol 1-bromo-4-((1,2,2-trifluorovinyl)oxy)benzene and 20 mL tetrahydrofuran was slowly added to the mixture. The mixture was stirred at room temperature for 24 h. After the reaction was completed, 120 mL toluene was added. After filtration, the mixture was distilled under reduced pressure at 75 °C to obtain aryltrifluorovinyl ether silane.

[0047] The specific equation is as follows:

[0048] ;

[0049] S5. Under argon protection, 0.04 mol of aryltrifluorovinyl ether silane was stirred and reacted at 175 °C for 9 h. After the reaction was completed, the unreacted raw material was removed by vacuum distillation at 80 °C to obtain perfluorocyclobutylaryl ether silane.

[0050] The specific equation is as follows:

[0051] ;

[0052] S6. Under argon protection, 1 mol of anhydrous acetic acid was heated to 90°C, and 0.01 mol of perfluorocyclobutylaryl ether silane and 0.01 mol of dimethyldiethoxysilane were slowly added dropwise. The mixture was refluxed for 24 h. After the reaction was completed, it was cooled to room temperature, and the acetic acid was removed by rotary evaporation. The volatile components were removed by vacuum distillation at 10 kPa and 60°C to obtain perfluorocyclobutylaryl ether silicone oil.

[0053] The specific equation is as follows:

[0054] ;

[0055] S7. 10g of aminosiloxane-modified phenylphenthiazide, 12g of friction index improver sulfurized fatty acid amine salt, 0.3g of perfluorocyclobutyl aryl ether silicone oil, 18.68g of thiophosphite amine salt, 28.01g of phosphate ester, 23.34g of phosphonate ester, 4.67g of thiophosphate ester and 3g of rust inhibitor benzotriazole were added to the reaction vessel in sequence. The mixture was stirred at 300r / min for 60min. After mixing, it was allowed to stand for 60min to obtain a composite additive for pure electric vehicle gearbox oil.

[0056] Example 2 A composite additive for gearbox oil in pure electric vehicles, comprising the following components by mass percentage: 8% antioxidant aminosiloxane-modified phenylphenthiazide, 15% friction index improver phosphate ester, 0.1% antifoaming agent perfluorocyclobutyl aryl ether silicone oil, 74.9% antiwear agent and 2% rust inhibitor benzotriazole, wherein the antiwear agent includes thiophosphite amine salt, phosphate ester, phosphonate ester and thiophosphate ester, and the mass ratio of thiophosphite amine salt, phosphate ester, phosphonate ester and thiophosphate ester is 4:6:5:1.

[0057] This embodiment also provides a method for preparing the above-mentioned composite additive for pure electric vehicle gearbox oil, specifically including the following steps:

[0058] S1. Take 1 mol of phenothiazine, 0.8 mol of copper powder, 3.26 mol of potassium carbonate and 2.1 mol of iodobenzene, add them to 300 mL of chlorobenzene, heat to 195 °C and react for 10 h. After the reaction is complete, cool to room temperature, then heat to 195 °C again and distill to remove the remaining iodobenzene. After cooling to room temperature again, add 300 mL of anhydrous ethanol, heat to 70 °C and stir for 10 min, then filter immediately. Collect the filtrate and crystallize at room temperature. Filter and collect the precipitate and dry at 60 °C to obtain phenylphenothiazine.

[0059] S2. Dissolve 3 mol of phenylphenthiazide in 20 mL of tetrahydrofuran, add 2.8 mol of N-bromosuccinamide in an ice-water bath at 5 °C, control the reaction temperature at 3 °C, react for 8 h, then pour the reaction solution into water and stir to precipitate solid. After filtration, wash the filter cake with distilled water and dry the filter cake at 80 °C to obtain bromophenylphenthiazide.

[0060] S3. Under nitrogen protection, 6 mL of toluene, 1 mol of bromophenylphenthiazide, and 3 mol of 3-aminopropyltriethoxysilane were mixed. 0.025 mol of tridibenzylacetone dipalladium catalyst and 0.04 mol of 4,5-bis(diphenylphosphine-9,9-dimethyloxanthracene) were added, along with 1.4 mol of potassium tert-butoxide. The mixture was reacted at 80 °C for 6 h. After the reaction was completed, the mixture was cooled and filtered. The resulting residue was washed three times with ethyl acetate, then distilled under reduced pressure at 6.7 kPa and 30 °C. The residue was then purified by alkaline alumina chromatography to obtain aminosiloxane-modified phenylphenthiazide. The chromatography purification used a 1:1 volume ratio of petroleum ether and ethyl acetate as the eluent.

[0061] S4. Under argon protection, 0.8 mol magnesium powder, 0.49 mol dimethyldimethoxysilane and 180 mL tetrahydrofuran were mixed. Then, a mixed solution of 0.16 mol 1-bromo-4-((1,2,2-trifluorovinyl)oxy)benzene and 20 mL tetrahydrofuran was slowly added to the mixture. The mixture was stirred at room temperature for 24 h. After the reaction was completed, 120 mL toluene was added. After filtration, the mixture was distilled under reduced pressure at 75 °C to obtain aryltrifluorovinyl ether silane.

[0062] S5. Under argon protection, 0.04 mol of aryltrifluorovinyl ether silane was stirred and reacted at 175 °C for 9 h. After the reaction was completed, the unreacted raw material was removed by vacuum distillation at 80 °C to obtain perfluorocyclobutylaryl ether silane.

[0063] S6. Under argon protection, 1 mol of anhydrous acetic acid was heated to 95°C, and 0.01 mol of perfluorocyclobutylaryl ether silane and 0.01 mol of dimethyldiethoxysilane were slowly added dropwise. The mixture was refluxed for 24 h. After the reaction was completed, it was cooled to room temperature, and the acetic acid was removed by rotary evaporation. The volatile components were removed by vacuum distillation at 10 kPa and 60°C to obtain perfluorocyclobutylaryl ether silicone oil.

[0064] S7. 8g of aminosiloxane-modified phenylphenthiazide, 15g of friction index improver phosphate ester, 0.1g of perfluorocyclobutyl aryl ether silicone oil, 18.73g of thiophosphite amine salt, 28.09g of phosphate ester, 23.40g of phosphonate ester, 4.68g of thiophosphate ester and 2g of rust inhibitor benzotriazole were added to the reaction vessel in sequence. The mixture was stirred at 400r / min for 40min. After mixing, it was allowed to stand for 40min to obtain a composite additive for pure electric vehicle gearbox oil.

[0065] Example 3 A composite additive for gearbox oil in pure electric vehicles, comprising the following components by mass percentage: 12% antioxidant aminosiloxane-modified phenylphenthiazide, 10% friction index improver sulfurized fatty acid amine salt, 0.5% antifoaming agent perfluorocyclobutyl aryl ether silicone oil, 72.5% anti-wear agent and 5% rust inhibitor benzotriazole, wherein the anti-wear agent includes thiophosphite amine salt, phosphate ester, phosphonate ester and thiophosphate ester, and the mass ratio of thiophosphite amine salt, phosphate ester, phosphonate ester and thiophosphate ester is 4:6:5:1.

[0066] This embodiment also provides a method for preparing the above-mentioned composite additive for pure electric vehicle gearbox oil, specifically including the following steps:

[0067] S1. Take 1 mol of phenothiazine, 0.76 mol of copper powder, 3.25 mol of potassium carbonate and 2.1 mol of iodobenzene, add them to 300 mL of chlorobenzene, heat to 193 °C and react for 10 h. After the reaction is complete, cool to room temperature, then heat to 195 °C and distill to remove the remaining iodobenzene. After cooling to room temperature again, add 300 mL of anhydrous ethanol, heat to 70 °C and stir for 10 min, then filter immediately. Collect the filtrate and crystallize at room temperature. Filter and collect the precipitate and dry at 60 °C to obtain phenylphenothiazine.

[0068] S2. Dissolve 3 mol of phenylphenthiazide in 20 mL of tetrahydrofuran, add 2.7 mol of N-bromosuccinamide in an ice-water bath at 5 °C, control the reaction temperature at 4 °C, react for 7 h, then pour the reaction solution into water and stir to precipitate solid. After filtration, wash the filter cake with distilled water and dry the filter cake at 80 °C to obtain bromophenylphenthiazide.

[0069] S3. Under nitrogen protection, 6 mL of toluene, 1 mol of bromophenylphenthiazide, and 3 mol of 3-aminopropyltriethoxysilane were mixed. 0.025 mol of tridibenzylacetone dipalladium catalyst and 0.035 mol of 4,5-bis(diphenylphosphine-9,9-dimethyloxanthracene) were added, along with 1.4 mol of potassium tert-butoxide. The mixture was reacted at 83 °C for 5 h. After the reaction was completed, the mixture was cooled and filtered. The resulting residue was washed three times with ethyl acetate, then distilled under reduced pressure at 6.7 kPa and 30 °C. The residue was then purified by alkaline alumina chromatography to obtain aminosiloxane-modified phenylphenthiazide. The chromatography purification used a 1:1 volume ratio of petroleum ether and ethyl acetate as the eluent.

[0070] S4. Under argon protection, 0.8 mol magnesium powder, 0.49 mol dimethyldimethoxysilane and 180 mL tetrahydrofuran were mixed. Then, a mixed solution of 0.16 mol 1-bromo-4-((1,2,2-trifluorovinyl)oxy)benzene and 20 mL tetrahydrofuran was slowly added to the mixture. The mixture was stirred at room temperature for 24 h. After the reaction was completed, 120 mL toluene was added. After filtration, the mixture was distilled under reduced pressure at 75 °C to obtain aryltrifluorovinyl ether silane.

[0071] S5. Under argon protection, 0.04 mol of aryltrifluorovinyl ether silane was stirred and reacted at 175 °C for 9 h. After the reaction was completed, the unreacted raw material was removed by vacuum distillation at 80 °C to obtain perfluorocyclobutylaryl ether silane.

[0072] S6. Under argon protection, 1 mol of anhydrous acetic acid was heated to 93°C, and 0.01 mol of perfluorocyclobutylaryl ether silane and 0.01 mol of dimethyldiethoxysilane were slowly added dropwise. The mixture was refluxed for 24 h. After the reaction was completed, it was cooled to room temperature, and the acetic acid was removed by rotary evaporation. The volatile components were removed by vacuum distillation at 10 kPa and 60°C to obtain perfluorocyclobutylaryl ether silicone oil.

[0073] S7. 12g of aminosiloxane-modified phenylphenthiazide, 10g of friction index improver sulfurized fatty acid amine salt, 0.5g of perfluorocyclobutyl aryl ether silicone oil, 18.12g of thiophosphite amine salt, 27.19g of phosphate ester, 22.66g of phosphonate ester, 4.53g of thiophosphate ester and 5g of rust inhibitor benzotriazole were added to the reaction vessel in sequence. The mixture was stirred at 350r / min for 50min. After mixing, it was allowed to stand for 50min to obtain a composite additive for pure electric vehicle gearbox oil.

[0074] Example 4 A composite additive for gearbox oil in pure electric vehicles, comprising the following components by mass percentage: 12% antioxidant aminosiloxane-modified phenylphenthiazide, 12.5% ​​friction index improver sulfurized fatty acid amine salt, 0.5% antifoaming agent perfluorocyclobutyl aryl ether silicone oil, 70% anti-wear agent and 5% rust inhibitor benzotriazole, wherein the anti-wear agent includes thiophosphite amine salt, phosphate ester, phosphonate ester and thiophosphate ester, and the mass ratio of thiophosphite amine salt, phosphate ester, phosphonate ester and thiophosphate ester is 4:6:5:1.

[0075] This embodiment also provides a method for preparing the above-mentioned composite additive for pure electric vehicle gearbox oil, specifically including the following steps:

[0076] S1. Take 1 mol of phenothiazine, 0.73 mol of copper powder, 3.23 mol of potassium carbonate and 2.1 mol of iodobenzene, add them to 300 mL of chlorobenzene, heat to 190 °C and react for 10 h. After the reaction is complete, cool to room temperature, then heat to 195 °C and distill to remove the remaining iodobenzene. After cooling to room temperature again, add 300 mL of anhydrous ethanol, heat to 70 °C and stir for 10 min, then filter immediately. Collect the filtrate and crystallize at room temperature. Filter and collect the precipitate and dry at 60 °C to obtain phenylphenothiazine.

[0077] S2. Dissolve 3 mol of phenylphenthiazide in 20 mL of tetrahydrofuran, add 2.5 mol of N-bromosuccinamide in an ice-water bath at 5 °C, control the reaction temperature at 5 °C, react for 6 h, then pour the reaction solution into water and stir to precipitate solid. After filtration, wash the filter cake with distilled water and dry the filter cake at 80 °C to obtain bromophenylphenthiazide.

[0078] S3. Under nitrogen protection, 6 mL of toluene, 1 mol of bromophenylphenthiazide, and 3 mol of 3-aminopropyltriethoxysilane were mixed. 0.025 mol of tridibenzylacetone dipalladium and 0.03 mol of 4,5-bis(diphenylphosphine-9,9-dimethyloxanthracene) catalyst were added, along with 1.4 mol of potassium tert-butoxide. The mixture was reacted at 80 °C for 6 h. After the reaction was completed, the mixture was cooled and filtered. The resulting residue was washed three times with ethyl acetate, then distilled under reduced pressure at 6.7 kPa and 30 °C. The residue was then purified by alkaline alumina chromatography to obtain aminosiloxane-modified phenylphenthiazide. The chromatography purification used a 1:1 volume ratio of petroleum ether and ethyl acetate as the eluent.

[0079] S4. Under argon protection, 0.8 mol magnesium powder, 0.49 mol dimethyldimethoxysilane and 180 mL tetrahydrofuran were mixed. Then, a mixed solution of 0.16 mol 1-bromo-4-((1,2,2-trifluorovinyl)oxy)benzene and 20 mL tetrahydrofuran was slowly added to the mixture. The mixture was stirred at room temperature for 24 h. After the reaction was completed, 120 mL toluene was added. After filtration, the mixture was distilled under reduced pressure at 75 °C to obtain aryltrifluorovinyl ether silane.

[0080] S5. Under argon protection, 0.04 mol of aryltrifluorovinyl ether silane was stirred and reacted at 175 °C for 9 h. After the reaction was completed, the unreacted raw material was removed by vacuum distillation at 80 °C to obtain perfluorocyclobutylaryl ether silane.

[0081] S6. Under argon protection, 1 mol of anhydrous acetic acid was heated to 90°C, and 0.01 mol of perfluorocyclobutylaryl ether silane and 0.01 mol of dimethyldiethoxysilane were slowly added dropwise. The mixture was refluxed for 24 h. After the reaction was completed, it was cooled to room temperature, and the acetic acid was removed by rotary evaporation. The volatile components were removed by vacuum distillation at 10 kPa and 60°C to obtain perfluorocyclobutylaryl ether silicone oil.

[0082] S7. 12g of aminosiloxane-modified phenylphenthiazide, 12.5g of friction index improver sulfurized fatty acid amine salt, 0.5g of perfluorocyclobutyl aryl ether silicone oil, 17.50g of thiophosphite amine salt, 26.25g of phosphate ester, 21.87g of phosphonate ester, 4.38g of thiophosphate ester and 5g of rust inhibitor benzotriazole were added to the reaction vessel in sequence. The mixture was stirred at 300r / min for 60min. After mixing, it was allowed to stand for 60min to obtain a composite additive for pure electric vehicle gearbox oil.

[0083] Example 5 A composite additive for gearbox oil in pure electric vehicles, comprising the following components by mass percentage: 8% antioxidant aminosiloxane-modified phenylphenthiazide, 11.5% friction index improver sulfurized fatty acid amine salt, 0.5% antifoaming agent perfluorocyclobutyl aryl ether silicone oil, 78% anti-wear agent and 2% rust inhibitor benzotriazole, wherein the anti-wear agent includes thiophosphite amine salt, phosphate ester, phosphonate ester and thiophosphate ester, and the mass ratio of thiophosphite amine salt, phosphate ester, phosphonate ester and thiophosphate ester is 4:6:5:1.

[0084] The preparation method of the pure electric vehicle gearbox oil composite additive in this embodiment is the same as that in Example 1.

[0085] Comparative Example 1 This comparative example provides a composite additive for a pure electric vehicle gearbox oil, comprising the following components by mass percentage: 10% antioxidant phenylphenthiazide, 12% friction index improver sulfurized fatty acid amine salt, 0.3% antifoaming agent perfluorocyclobutyl aryl ether silicone oil, 74.7% antiwear agent and 3% rust inhibitor benzotriazole, wherein the antiwear agent includes thiophosphite amine salt, phosphate ester, phosphonate ester and thiophosphate ester, and the mass ratio of thiophosphite amine salt, phosphate ester, phosphonate ester and thiophosphate ester is 4:6:5:1.

[0086] Comparative Example 2 This comparative example provides a composite additive for a pure electric vehicle gearbox oil, comprising the following components by mass percentage: 10% antioxidant phenothiazine, 12% friction index improver sulfurized fatty acid amine salt, 0.3% antifoaming agent perfluorocyclobutyl aryl ether silicone oil, 74.7% antiwear agent and 3% rust inhibitor benzotriazole, wherein the antiwear agent includes thiophosphite amine salt, phosphate ester, phosphonate ester and thiophosphate ester, and the mass ratio of thiophosphite amine salt, phosphate ester, phosphonate ester and thiophosphate ester is 4:6:5:1.

[0087] Comparative Example 3 This comparative example provides a composite additive for a pure electric vehicle gearbox oil, comprising the following components by mass percentage: 10% of antioxidant aminosiloxane-modified phenylphenthiazide, 12% of friction index improver sulfurized fatty acid amine salt, 0.3% of antifoaming agent silicone oil, 74.7% of antiwear agent and 3% of rust inhibitor benzotriazole, wherein the antiwear agent includes thiophosphite amine salt, phosphate ester, phosphonate ester and thiophosphate ester, and the mass ratio of thiophosphite amine salt, phosphate ester, phosphonate ester and thiophosphate ester is 4:6:5:1.

[0088] Take 0.5g of the composite additive from Example 1 and Comparative Examples 1-3 and mix it with 95.5g of SK YUBASE® 4 base oil to prepare gearbox oil.

[0089] The oxidation performance of the gearbox oils prepared by the composite additives for pure electric vehicle gearbox oils in Example 1 and Comparative Examples 1-3 was tested. Specifically, the oxidation induction period (OIT) of each sample was tested by rotating bomb oxidation test (RBOT) as the test index of oxidation performance.

[0090] Add 50g of gearbox oil sample, 55.6g of 99.5% copper coil, and 5mL of distilled water to a glass test dish. Seal the test dish in a stainless steel projectile and fill it with 620kPa of pure oxygen at 25℃. Heat the projectile in dimethyl silicone oil to 180℃ and keep it rotating. Record the time when the maximum pressure drops by 175kPa, which is recorded as the oxidation induction period of the gearbox oil.

[0091] Take another glass test dish and continue the oxidation induction period test. In this test, the projectile is heated to 150°C in dimethyl silicone oil, and the oxidation induction period of the gearbox oil is recorded.

[0092] The oxidation induction period results of the gearbox oils prepared in Example 1 and Comparative Examples 1-3 are as follows: Figure 1 As shown, by Figure 1 It can be seen that the oxidation induction period of the gearbox oil obtained in Comparative Example 3 and Example 1 is not much different, while the oxidation induction period of the gearbox oil obtained in Comparative Example 2 is much lower than that in Example 1. Furthermore, the oxidation induction periods of the gearbox oil obtained in Comparative Example 1 and Comparative Example 2 are similar. This is because the multiple secondary amine groups in the aminosiloxane-modified phenylphenthiazide can improve the oxidation induction period of the gearbox oil and have a better antioxidant effect.

[0093] Furthermore, the comparison of the oxidation induction period at 150℃ and 180℃ in Table 1 shows that the high-temperature antioxidant effect of phenylphenthiazide modified with aminosiloxane did not decrease significantly, while the high-temperature antioxidant effect of Comparative Example 1 and Comparative Example 2 decreased significantly without the modification of phenylphenthiazide with aminosiloxane.

[0094] The viscosity and sediment changes of the gearbox oils in Example 1 and Comparative Examples 1-3 were tested respectively. The specific methods are as follows: A glass test tube containing 50g of gearbox oil sample was placed in a heated oil bath at 180℃. Dry air was introduced into the sample at a flow rate of 50mL / min. The oxidation time was 140h. After the oxidation was completed, the sample was poured into a 100mL centrifuge tube and centrifuged at 1825r / min for half an hour. The lower part of the sample was taken out and washed with petroleum ether. The petroleum ether insoluble matter was filtered with filter paper, dried, and weighed. The total sediment was recorded as the total sediment.

[0095] The total sediment test results of gearbox oil prepared using the composite additive of Example 1 and Comparative Examples 1-3 as gearbox oil additives are as follows: Figure 2 As shown.

[0096] Depend on Figure 2 It can be seen that the total amount of sediment in Comparative Example 3 and Example 1 is about the same, while the total amount of sediment in Comparative Example 1 and Comparative Example 2 is greater than that in Example 1, and Comparative Example 2 has more sediment than Comparative Example 1. Attaching a benzene ring to the N of phenothiazine can reduce the generation of sludge. Furthermore, using aminosiloxane to modify phenylphenothiazine, the flexible structure of the siloxane chain can encapsulate the active group of phenothiazine, further reducing the generation of sludge.

[0097] The anti-foaming properties of the gearbox oils prepared by the composite additives of Example 1 and Comparative Examples 1-3 as gearbox oil additives were tested. The test method was based on GB / T 12579-2002, and the specific method is as follows: 50g of gearbox oil sample was placed in a graduated cylinder and preheated to the test temperature in a constant temperature bath at 24℃. The gas diffuser was immersed in the bottom of the sample, and dry air was introduced at 94mL / min for 5min. The foam volume was recorded immediately after the air was introduced as the foam tendency result. After the air was introduced, the sample was allowed to stand for 10min, and the foam volume was recorded again as the foam stability result.

[0098] Change the test temperature to 93.5℃ and conduct the test again. Record the foam tendency and foam stability results respectively. After the foam disappears, repeat the test at 24℃.

[0099] The results of the antifoaming performance test are shown in Table 1.

[0100] Table 1. Test results of anti-foaming properties of the gearbox oils prepared in Example 1 and Comparative Examples 1-3

[0101]

[0102] As can be seen from Table 1, in Comparative Example 3, the antifoaming performance of the gearbox oil decreased when perfluorocyclobutyl aryl ether silicone oil was not used as an antifoaming agent. This is because the close arrangement of fluorine atoms in the perfluorocyclobutyl ether can further reduce the surface tension of the silicone oil and improve the defoaming effect.

[0103] Insulation performance tests were conducted on the gearbox oils prepared using the composite additives of Example 1 and Comparative Examples 1-3 as gearbox oil additives. The test methods were based on GB / T 5654-2007, and the specific methods are as follows: After preheating the gearbox oil sample at 90℃ for 30 min, the sample was slowly poured into the electrode cup, ensuring that the liquid surface completely covered the electrodes. The electrode spacing was 3 mm, the electrode material was platinum-plated, and the electrode surface finish Ra≤0.1μm. Then, a DC power supply was connected, and a voltage of 500V was applied and stabilized for 1 min. The current value after stabilization was recorded, and the volume resistivity was calculated. The formula for calculating the volume resistivity is: Volume resistivity = (Applied voltage / Current value) × (Electrode effective area / Electrode spacing). The experimental results are as follows. Figure 3 As shown.

[0104] Depend on Figure 3 It can be seen that the volume resistivity of the gearbox oil prepared in Comparative Example 3 is lower than that of Example 1, Comparative Example 1, and Comparative Example 2, indicating that perfluorocyclobutyl aryl ether silicone oil can improve the electrical insulation performance of gearbox oil.

[0105] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A composite additive for gearbox oil in pure electric vehicles, characterized in that, By mass percentage, it includes the following components: 8-12% antioxidant, 10-15% friction index improver, 0.1-0.5% antifoaming agent, 70-78% anti-wear agent, and 2-5% rust inhibitor; The antioxidant is aminosiloxane-modified phenylphenthiazine, and the antifoaming agent is perfluorocyclobutyl aryl ether silicone oil; The preparation method of the aminosiloxane-modified phenylphenthiazide is as follows: under nitrogen protection, toluene, bromophenylphenthiazide and 3-aminopropyltriethoxysilane are mixed, and the catalysts tridibenzylacetone dipalladium and 4,5-bisdiphenylphosphine-9,9-dimethyloxanthracene are added to the mixture. Potassium tert-butoxide is added at the same time, and the mixture is reacted at 80~85℃ for 4~6h. After the reaction is completed, the mixture is cooled and filtered. The filter residue is washed with ethyl acetate, and then distilled under reduced pressure at 6.7KPa and 30℃. The residue is then separated and purified by alkaline alumina chromatography column to obtain aminosiloxane-modified phenylphenthiazide. The preparation method of the perfluorocyclobutyl aryl ether silicone oil is as follows: aryl trifluorovinyl ether silane is prepared by Grignard reaction using dimethyldimethoxysilane and 1-bromo-4-((1,2,2-trifluorovinyl)oxy)benzene as raw materials; perfluorocyclobutyl aryl ether silane is prepared by thermal cyclization reaction using aryl trifluorovinyl ether silane as raw material under argon protection; perfluorocyclobutyl aryl ether silane is prepared by reaction at 90~95℃ for 24h using anhydrous acetic acid as solvent and perfluorocyclobutyl aryl ether silane and dimethyldiethoxysilane as raw materials under argon protection, and after the reaction is completed, the mixture is cooled to room temperature, acetic acid is removed by rotary evaporation, and perfluorocyclobutyl aryl ether silicone oil is obtained by vacuum distillation.

2. The composite additive for pure electric vehicle gearbox oil according to claim 1, characterized in that, The anti-wear agent comprises thiophosphite amine salt, phosphate ester, phosphonate ester and thiophosphate ester in a mass ratio of 4:6:5:1; the rust inhibitor is benzotriazole; and the friction index improver is phosphate ester or sulfurized fatty acid amine salt.

3. The composite additive for pure electric vehicle gearbox oil according to claim 2, characterized in that, By weight percentage, it includes the following components: 10% antioxidant, 12% friction index improver, 0.3% antifoaming agent, 74.7% anti-wear agent and 3% rust inhibitor.

4. A method for preparing the composite additive for pure electric vehicle gearbox oil according to claim 1, characterized in that, Includes the following steps: S1. Under nitrogen protection, toluene, bromophenylphenthiazide, and 3-aminopropyltriethoxysilane were mixed, and the catalysts tridibenzylacetone dipalladium and 4,5-bisdiphenylphosphine-9,9-dimethyloxanthracene were added. Potassium tert-butoxide was added at the same time, and the mixture was reacted at 80-85℃ for 4-6 h. After the reaction was completed, the mixture was cooled and filtered. The filter residue was washed with ethyl acetate, and then purified by vacuum distillation at 6.7 kPa and 30℃ using an alkaline alumina chromatography column to obtain aminosiloxane-modified phenylphenthiazide. S2. Aryltrifluorovinyl ether silane was prepared by Grignard reaction using dimethyldimethoxysilane and 1-bromo-4-((1,2,2-trifluorovinyl)oxy)benzene as raw materials. Under argon protection, perfluorocyclobutylaryl ether silane was prepared by thermal cyclization reaction using aryltrifluorovinyl ether silane as a raw material. Under argon protection, using anhydrous acetic acid as solvent, perfluorocyclobutylaryl ether silane and dimethyldiethoxysilane as raw materials, the reaction was carried out at 90~95℃ for 24h. After the reaction was completed, the mixture was cooled to room temperature, acetic acid was removed by rotary evaporation, and perfluorocyclobutylaryl ether silicone oil was obtained by vacuum distillation. S3. Add aminosiloxane-modified phenylphenthiazide, perfluorocyclobutyl aryl ether silicone oil, friction index improver, anti-wear agent and rust inhibitor to the reaction vessel in sequence, stir at 300~400 r / min for 40~60 min, and let stand for 40~60 min after mixing to obtain pure electric vehicle gearbox oil composite additive.

5. The preparation method of the composite additive for pure electric vehicle gearbox oil according to claim 4, characterized in that, In step S1, the preparation method of the bromophenylphenthiazide is as follows: dissolve phenylphenthiazide in tetrahydrofuran, add N-bromosuccinamide to it under ice-water bath conditions at 5°C, control the reaction temperature at 3~5°C, react for 6~8 hours, then pour the reaction solution into water and stir to precipitate solid, filter, wash the filter cake with distilled water, and dry the filter cake to obtain bromophenylphenthiazide.

6. The preparation method of the composite additive for pure electric vehicle gearbox oil according to claim 5, characterized in that, The preparation method of the phenylphenothiazine is as follows: phenothiazine, copper powder, potassium carbonate and iodobenzene are added to chlorobenzene, heated to 190~195℃ and reacted for 10h. After the reaction is completed, the temperature is lowered to room temperature, and then heated to 195℃ again for distillation to remove the remaining iodobenzene. After cooling to room temperature again, anhydrous ethanol is added, the temperature is raised to 70℃ and stirred for 10min, and then filtered immediately. The filtrate is collected and crystallized at room temperature. The precipitate is collected by filtration and dried to obtain phenylphenothiazine.

7. The preparation method of the composite additive for pure electric vehicle gearbox oil according to claim 4, characterized in that, In step S1, the molar ratio of bromophenylphenthiazide, 3-aminopropyltriethoxysilane, tridibenzylacetone dipalladium, 4,5-bisdiphenylphosphine-9,9-dimethyloxanthracene and potassium tert-butoxide is 1:3:0.025:0.03~0.04:1.4, and the eluent used in the chromatography column separation and purification process is a mixed solvent of petroleum ether and ethyl acetate in a volume ratio of 1:

1.

8. The preparation method of the composite additive for pure electric vehicle gearbox oil according to claim 4, characterized in that, In step S2, the molar ratio of the perfluorocyclobutylaryl ether silane and the dimethyldiethoxysilane is 1:

1.

9. The preparation method of the composite additive for pure electric vehicle gearbox oil according to claim 5, characterized in that, The molar ratio of the phenylphenthiazide to the N-bromosuccinamide is 3:2.5~2.

8.

10. The preparation method of the composite additive for pure electric vehicle gearbox oil according to claim 6, characterized in that, The molar ratio of phenothiazine, iodobenzene, copper powder and potassium carbonate is 1:2.1:0.73~0.8:3.23~3.26.

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