Low-temperature-resistant vehicle brake fluid and preparation method thereof

Abstract

The invention relates to the technical field of vehicle brake fluids, in particular to a low-temperature-resistant vehicle brake fluid and a preparation method thereof. The low-temperature-resistant vehicle brake fluid is prepared from the following raw materials in parts by mass: 5 to 10 parts of boric acid, 10 to 15 parts of polydimethylsiloxane glycol, 1 to 2 parts of silane coupling agent, 0.5 to 1 part of amino-terminated polyamidoamine, 5 to 10 parts of polyethylene glycol borate, 5 to 10 parts of triethylene glycol monomethyl ether borate, 5 to 10 parts of diethylene glycol monobutyl ether, 10 to 25 parts of triethylene glycol, 5 to 10 parts of 1, 4-butanediol and 10 to 15 parts of ethylene glycol. 5-15 parts of dipropylene glycol monomethyl ether, 1-3 parts of antioxidant, 1-3 parts of organic acid and 1-3 parts of pH regulator. The brake fluid obtained by the invention has good low-temperature fluidity, excellent corrosion and rust resistance, better oxidation resistance and good water resistance.

Description

Technical Field

[0001] This invention relates to the field of vehicle brake fluid technology, and in particular to a low-temperature resistant vehicle brake fluid and its preparation method. Background Technology

[0002] The automotive industry is a pillar industry of my country's national economy. In this industrial system, brake fluid, as an important functional medium of the hydraulic braking system, has a performance that is directly related to vehicle driving safety.

[0003] Modern automotive hydraulic braking systems rely on brake fluid to transmit pressure. The 2MPa working pressure generated by the master cylinder (not exceeding 4MPa under extreme conditions) is evenly transmitted to the wheel cylinders through sealed lines, ultimately actuating the brakes to achieve braking. Because liquids are incompressible, brake fluid ensures the immediacy and precision of pressure transmission, which is the physical basis for achieving efficient braking.

[0004] With the technological iteration of the automotive industry, braking systems are developing towards higher performance and adaptability to extreme environments. In traditional brake fluids, moisture can seep into the system through seals during long-term use, causing phase separation between the base fluid and water, resulting in sedimentation and significantly reducing hydraulic transmission efficiency. On the one hand, existing products lack self-repair mechanisms, allowing microstructural damage caused by moisture intrusion to accumulate continuously. On the other hand, in low-temperature environments, the viscosity of traditional brake fluids exhibits a sudden increase, and fluidity decreases significantly, leading to delayed braking response.

[0005] The current challenge is to balance the contradiction between high-temperature resistance to vapor lock and low-temperature fluidity, and to balance self-healing capability with the stability of the base fluid, so as to improve the reliability of braking systems under extreme conditions such as cold-weather highways and high-altitude mountainous areas. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by proposing a low-temperature resistant vehicle brake fluid and its preparation method.

[0007] A low-temperature resistant vehicle brake fluid, comprising the following raw materials by weight: 5-10 parts boric acid, 10-15 parts polydimethylsiloxane diol, 1-2 parts silane coupling agent, 0.5-1 part amino-terminated polyamide amine, 5-10 parts polyethylene glycol borate, 5-10 parts triethylene glycol methyl ether borate, 5-10 parts diethylene glycol butyl ether, 10-25 parts triethylene glycol, 5-10 parts 1,4-butanediol, 10-15 parts ethylene glycol, 5-15 parts dipropylene glycol monomethyl ether, 1-3 parts antioxidant, 1-3 parts organic acid, and 1-3 parts pH adjuster.

[0008] Preferably, its equilibrium reflux boiling point is 265-275℃.

[0009] Preferably, its wet equilibrium reflux boiling point is 180-186℃.

[0010] Preferably, its kinematic viscosity at -40°C is 728-750 mmHg. 2 / s.

[0011] Preferably, the antioxidant is at least one of 4-methyl-2,6-di-tert-butylphenol, dialkyldiphenylamine, and octylbutyldiphenylamine.

[0012] Preferably, the organic acid is at least one of ricinoleic acid, tartaric acid, and lactic acid.

[0013] Preferably, the pH adjuster is triethanolamine and / or methyldiethanolamine.

[0014] Preferably, the generation of the terminal amino polyamide amine is 2.0-4.0.

[0015] The preparation method of the above-mentioned low-temperature resistant vehicle brake fluid includes the following steps: S1. Add boric acid to the solvent and stir evenly. Add polydimethylsiloxane diol to it and reflux at 70-80℃ for 1-2 hours. Reduce the temperature to 50-60℃, add silane coupling agent and amino-terminated polyamide amine and continue stirring for 1-2 hours. Cool to room temperature to obtain the self-healing modifier. S2. Mix polyethylene glycol borate, triethylene glycol methyl ether borate, diethylene glycol butyl ether, triethylene glycol, 1,4-butanediol, ethylene glycol, and dipropylene glycol monomethyl ether evenly, and stir at 70-80℃ for 10-20 minutes to obtain the preform. S3. Add the self-healing modifier to the preform under stirring, stir for 5-10 minutes, add the antioxidant and organic acid and stir for 1-3 minutes, then add the pH adjuster and stir evenly, and filter.

[0016] Preferably, the solvent is a mixed solvent, which includes hexafluoroisopropanol and perfluoropolyether, with a weight ratio of hexafluoroisopropanol to perfluoropolyether of 10:1.

[0017] The above-mentioned low-temperature resistant vehicle brake fluid is used as an automotive brake fluid.

[0018] Beneficial effects: This invention utilizes flexible segments of polydimethylsiloxane diol to form a dynamic, reversible network with boric acid via boronic acid ester bonds. The network's pores accommodate moisture, and the amino groups of the terminal amino-terminated polyamide amine interact with the hydroxyl groups of the polyethylene glycol boronic acid ester, enhancing phase compatibility and effectively preventing phase separation and precipitation caused by moisture intrusion. When moisture intrudes, the dynamic boronic acid ester bonds break and realign, achieving self-repair of the network structure and preventing precipitation due to water phase separation. Furthermore, the coupling agent KH-560 further enhances the compatibility of the organic-inorganic interface through a silane hydrolysis-condensation reaction.

[0019] This invention utilizes the synergistic effect of triethylene glycol methyl ether borate and 1,4-butanediol. The ethylene glycol ether segment forms intramolecular hydrogen bonds with the hydroxyl group, reducing the tendency for low-temperature crystallization. Meanwhile, the linear structure of polyethylene glycol maintains Newtonian fluid properties at low temperatures, and at high temperatures, its ether oxygen atoms form intermolecular forces with the oxygen atoms of the borate, enhancing resistance to vapor barrier. At the same time, the branched structure of dipropylene glycol monomethyl ether inhibits the orderly arrangement of molecules and reduces viscosity abrupt changes.

[0020] This invention utilizes fluorine atoms to create a locally hydrophobic microenvironment, neutralizes the carboxyl groups of organic acids with the amino groups of triethanolamine, adjusts the pH of the system, inhibits corrosion of metal parts, and, in conjunction with antioxidants, significantly delays oxidative degradation.

[0021] The brake fluid obtained by this invention has good low-temperature fluidity, excellent anti-corrosion and anti-rust properties, and good oxidation resistance, as well as good water resistance. When water enters the automotive brake fluid, it exhibits excellent self-repairing effects, is not prone to separation and precipitation, enhances the uniformity and stability of the automotive brake fluid, thereby significantly improving the safety performance of the brake fluid. Furthermore, the preparation process is simple, the raw materials used are readily available, and it is easy to achieve large-scale production. Attached Figure Description

[0022] Figure 1 This is a comparison chart of the equilibrium reflux boiling point and wet equilibrium reflux boiling point of the vehicle brake fluids obtained in Example 5 and Comparative Examples 1-2.

[0023] Figure 2 The graph shows a comparison of the corrosiveness of the vehicle brake fluids obtained in Example 5 and Comparative Examples 1-2 to cast iron and their kinematic viscosity at -40°C. Detailed Implementation

[0024] The present invention will be further explained below with reference to specific embodiments.

[0025] The amino-terminated polyamide amines (ethylenediamine as the core of the synthesis, G3.0) used below were purchased from Shanghai Mouen Chemical Technology Co., Ltd.

[0026] The mixed solvents used below include hexafluoroisopropanol and perfluoropolyether, with a weight ratio of hexafluoroisopropanol to perfluoropolyether of 10:1.

[0027] Example 1 A low-temperature resistant vehicle brake fluid, comprising the following raw materials: 50g boric acid, 100g polydimethylsiloxane diol, 10g coupling agent KH-560, 5g amino-terminated polyamide amine, 50g polyethylene glycol borate, 50g triethylene glycol methyl ether borate, 50g diethylene glycol butyl ether, 100g triethylene glycol, 50g 1,4-butanediol, 100g ethylene glycol, 50g dipropylene glycol monomethyl ether, 10g 4-methyl-2,6-di-tert-butylphenol, 10g castor oil acid, and 10g methyl diethanolamine.

[0028] The preparation method of the above-mentioned low-temperature resistant vehicle brake fluid includes the following steps: S1. Add boric acid to 300g of mixed solvent and stir evenly. Add polydimethylsiloxane diol to it and reflux at 70℃ for 1h. Cool down to 50℃, add coupling agent KH-560 and amino-terminated polyamide amine and continue stirring for 1h. Heat to remove hexafluoroisopropanol from the mixed solvent and cool to room temperature to obtain the self-healing modifier. S2. Mix polyethylene glycol borate, triethylene glycol methyl ether borate, diethylene glycol butyl ether, triethylene glycol, 1,4-butanediol, ethylene glycol, and dipropylene glycol monomethyl ether evenly, and stir at 70°C for 10 minutes to obtain the preform. S3. Add the self-healing modifier to the preform under stirring, stir for 5 minutes, add 4-methyl-2,6-di-tert-butylphenol and castor oil acid and stir for 1 minute, then add methyl diethanolamine and stir evenly, and filter with a 0.1μm filter.

[0029] Example 2 A low-temperature resistant vehicle brake fluid, the raw materials of which include: 100g boric acid, 150g polydimethylsiloxane diol, 20g coupling agent KH-560, 10g amino-terminated polyamide amine, 100g polyethylene glycol borate, 100g triethylene glycol methyl ether borate, 100g diethylene glycol butyl ether, 250g triethylene glycol, 100g 1,4-butanediol, 150g ethylene glycol, 150g dipropylene glycol monomethyl ether, 30g dialkyldiphenylamine, 30g tartaric acid, and 30g triethanolamine.

[0030] The preparation method of the above-mentioned low-temperature resistant vehicle brake fluid includes the following steps: S1. Add boric acid to 400g of mixed solvent and stir evenly. Add polydimethylsiloxane diol to it and reflux at 80℃ for 2h. Cool down to 60℃, add coupling agent KH-560 and amino-terminated polyamide amine and continue stirring for 2h. Heat to remove hexafluoroisopropanol from the mixed solvent and cool to room temperature to obtain the self-healing modifier. S2. Mix polyethylene glycol borate, triethylene glycol methyl ether borate, diethylene glycol butyl ether, triethylene glycol, 1,4-butanediol, ethylene glycol, and dipropylene glycol monomethyl ether evenly, and stir at 80°C for 20 minutes to obtain the preform. S3. Add the self-healing modifier to the preform under stirring, stir for 10 minutes, add dialkyldiphenylamine and tartaric acid and stir for 3 minutes, then add triethanolamine and stir evenly, and filter with a 0.1μm filter.

[0031] Example 3 A low-temperature resistant vehicle brake fluid, the raw materials of which include: 70g boric acid, 130g polydimethylsiloxane diol, 12g coupling agent KH-560, 9g amino-terminated polyamide amine, 70g polyethylene glycol borate, 90g triethylene glycol methyl ether borate, 70g diethylene glycol butyl ether, 200g triethylene glycol, 70g 1,4-butanediol, 130g ethylene glycol, 80g dipropylene glycol monomethyl ether, 15g octylbutyldiphenylamine, 25g lactic acid, and 15g methyl diethanolamine.

[0032] The preparation method of the above-mentioned low-temperature resistant vehicle brake fluid includes the following steps: S1. Add boric acid to 370g of mixed solvent and stir evenly. Add polydimethylsiloxane diol to it and reflux at 73℃ for 100min. Cool down to 52℃, add coupling agent KH-560 and amino-terminated polyamide amine and continue stirring for 100min. Heat to remove hexafluoroisopropanol from the mixed solvent and cool to room temperature to obtain the self-healing modifier. S2. Mix polyethylene glycol borate, triethylene glycol methyl ether borate, diethylene glycol butyl ether, triethylene glycol, 1,4-butanediol, ethylene glycol, and dipropylene glycol monomethyl ether evenly, and stir at 73°C for 18 minutes to obtain the preform. S3. Add the self-healing modifier to the preform under stirring, stir for 7 minutes, add octylbutyldiphenylamine and lactic acid and stir for 2 minutes, then add methyldiethanolamine and stir evenly, and filter with a 0.1μm filter.

[0033] Example 4 A low-temperature resistant vehicle brake fluid, the raw materials of which include: 90g boric acid, 110g polydimethylsiloxane diol, 18g coupling agent KH-560, 7g amino-terminated polyamide amine, 90g polyethylene glycol borate, 70g triethylene glycol methyl ether borate, 90g diethylene glycol butyl ether, 150g triethylene glycol, 90g 1,4-butanediol, 110g ethylene glycol, 120g dipropylene glycol monomethyl ether, 25g dialkyldiphenylamine, 15g lactic acid, and 25g triethanolamine.

[0034] The preparation method of the above-mentioned low-temperature resistant vehicle brake fluid includes the following steps: S1. Add boric acid to 330g of mixed solvent and stir evenly. Add polydimethylsiloxane diol to it and reflux at 77℃ for 80min. Cool down to 58℃, add coupling agent KH-560 and amino-terminated polyamide amine and continue stirring for 80min. Heat to remove hexafluoroisopropanol from the mixed solvent and cool to room temperature to obtain the self-healing modifier. S2. Mix polyethylene glycol borate, triethylene glycol methyl ether borate, diethylene glycol butyl ether, triethylene glycol, 1,4-butanediol, ethylene glycol, and dipropylene glycol monomethyl ether evenly, and stir at 77°C for 12 minutes to obtain the preform. S3. Add the self-healing modifier to the preform under stirring, stir for 9 minutes, add dialkyldiphenylamine and lactic acid and stir for 2 minutes, then add triethanolamine and stir evenly, and filter with a 0.1μm filter.

[0035] Example 5 A low-temperature resistant vehicle brake fluid, the raw materials of which include: 80g boric acid, 120g polydimethylsiloxane diol, 15g coupling agent KH-560, 8g amino-terminated polyamide amine, 80g polyethylene glycol borate, 80g triethylene glycol methyl ether borate, 80g diethylene glycol butyl ether, 180g triethylene glycol, 80g 1,4-butanediol, 120g ethylene glycol, 100g dipropylene glycol monomethyl ether, 20g 4-methyl-2,6-di-tert-butylphenol, 20g lactic acid, and 20g methyl diethanolamine.

[0036] The preparation method of the above-mentioned low-temperature resistant vehicle brake fluid includes the following steps: S1. Add boric acid to 350g of mixed solvent and stir evenly. Add polydimethylsiloxane diol to it and reflux at 75℃ for 90min. Cool down to 55℃, add coupling agent KH-560 and amino-terminated polyamide amine and continue stirring for 90min. Heat to remove hexafluoroisopropanol from the mixed solvent and cool to room temperature to obtain the self-healing modifier. S2. Mix polyethylene glycol borate, triethylene glycol methyl ether borate, diethylene glycol butyl ether, triethylene glycol, 1,4-butanediol, ethylene glycol, and dipropylene glycol monomethyl ether evenly, and stir at 75°C for 15 minutes to obtain the preform. S3. Add the self-healing modifier to the preform under stirring, stir for 8 minutes, add 4-methyl-2,6-di-tert-butylphenol and lactic acid and stir for 2 minutes, then add methyl diethanolamine and stir evenly, and filter with a 0.1μm filter.

[0037] Comparative Example 1 A low-temperature resistant vehicle brake fluid, the raw materials of which include: 88g boric acid, 135g polydimethylsiloxane diol, 80g polyethylene glycol borate, 80g triethylene glycol methyl ether borate, 80g diethylene glycol butyl ether, 180g triethylene glycol, 80g 1,4-butanediol, 120g ethylene glycol, 100g dipropylene glycol monomethyl ether, 20g 4-methyl-2,6-di-tert-butylphenol, 20g lactic acid, and 20g methyldiethanolamine.

[0038] The preparation method of the above-mentioned low-temperature resistant vehicle brake fluid includes the following steps: S1. Add boric acid to 350g of mixed solvent and stir evenly. Add polydimethylsiloxane diol to it, reflux and stir at 75℃ for 90min, cool down to 55℃ and continue stirring for 90min. Heat to remove hexafluoroisopropanol from the mixed solvent, and cool to room temperature to obtain the self-healing modifier. S2. Mix polyethylene glycol borate, triethylene glycol methyl ether borate, diethylene glycol butyl ether, triethylene glycol, 1,4-butanediol, ethylene glycol, and dipropylene glycol monomethyl ether evenly, and stir at 75°C for 15 minutes to obtain the preform. S3. Add the self-healing modifier to the preform under stirring, stir for 8 minutes, add 4-methyl-2,6-di-tert-butylphenol and lactic acid and stir for 2 minutes, then add methyl diethanolamine and stir evenly, and filter with a 0.1μm filter.

[0039] Comparative Example 2 A low-temperature resistant vehicle brake fluid, the raw materials of which include: 80g boric acid, 120g polydimethylsiloxane diol, 15g coupling agent KH-560, 8g amino-terminated polyamide amine, 80g polyethylene glycol borate, 80g triethylene glycol methyl ether borate, 80g diethylene glycol butyl ether, 180g triethylene glycol, 80g 1,4-butanediol, 120g ethylene glycol, 100g dipropylene glycol monomethyl ether, 20g 4-methyl-2,6-di-tert-butylphenol, 20g lactic acid, and 20g methyl diethanolamine.

[0040] The preparation method of the above-mentioned low-temperature resistant vehicle brake fluid includes the following steps: S1. Add boric acid to 350g of mixed solvent and stir evenly. Add polydimethylsiloxane diol to it, reflux and stir at 75℃ for 90min, cool down to 55℃ and continue stirring for 90min. Heat to remove hexafluoroisopropanol from the mixed solvent, and cool to room temperature to obtain the self-healing modifier. S2. Mix polyethylene glycol borate, triethylene glycol methyl ether borate, diethylene glycol butyl ether, triethylene glycol, 1,4-butanediol, ethylene glycol, and dipropylene glycol monomethyl ether evenly, and stir at 75°C for 15 minutes to obtain the preform. S3. Under stirring, add coupling agent KH-560, amino-terminated polyamide amine, and self-healing modifier to the preform and stir for 8 minutes. Then add 4-methyl-2,6-di-tert-butylphenol and lactic acid and stir for 2 minutes. Finally, add methyl diethanolamine and stir until homogeneous. Filter using a 0.1μm filter.

[0041] The vehicle brake fluids obtained in Example 5 and Comparative Examples 1-2 were left to stand for 48 hours, and the state of each group of brake fluids was observed. Experimental observation revealed that the vehicle brake fluids obtained in Example 5 and Comparative Examples 1-2 did not exhibit stratification, confirming that each group of brake fluids had good stability.

[0042] The equilibrium reflux boiling points of the vehicle brake fluids obtained in Example 5 and Comparative Examples 1-2 were determined according to NB / SH / T 0430-2019 "Determination of Equilibrium Reflux Boiling Point of Brake Fluid". The wet equilibrium reflux boiling points of the vehicle brake fluids obtained in Example 5 and Comparative Examples 1-2 were determined according to Appendix C of GB 12981-2012 "Motor Vehicle Brake Fluid".

[0043] like Figure 1 As shown, the vehicle brake fluid obtained in Example 5 has the highest equilibrium reflux boiling point and wet equilibrium reflux boiling point, which is significantly better than that of Comparative Examples 1-2.

[0044] The corrosiveness of the vehicle brake fluids obtained in Example 5 and Comparative Examples 1-2 to cast iron was tested according to Appendix F of GB 12981-2012 "Motor Vehicle Brake Fluid". The kinematic viscosity of the vehicle brake fluids obtained in Example 5 and Comparative Examples 1-2 at -40℃ was determined according to GB / T 265-1988 "Petroleum Products - Determination of Kinematic Viscosity and Calculation of Dynamic Viscosity".

[0045] like Figure 2 As shown, the vehicle brake fluid obtained in Example 5 has the least corrosiveness to cast iron, and its kinematic viscosity at -40°C is also the lowest, which is significantly better than that of Comparative Examples 1-2.

[0046] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A low-temperature resistant vehicle brake fluid, characterized in that, The raw materials, by weight, include: 5-10 parts boric acid, 10-15 parts polydimethylsiloxane diol, 1-2 parts silane coupling agent, 0.5-1 parts amino-terminated polyamide amine, 5-10 parts polyethylene glycol borate, 5-10 parts triethylene glycol methyl ether borate, 5-10 parts diethylene glycol butyl ether, 10-25 parts triethylene glycol, 5-10 parts 1,4-butanediol, 10-15 parts ethylene glycol, 5-15 parts dipropylene glycol monomethyl ether, 1-3 parts antioxidant, 1-3 parts organic acid, and 1-3 parts pH adjuster.

2. The low-temperature resistant vehicle brake fluid according to claim 1, characterized in that, Its equilibrium reflux boiling point is 265-275℃.

3. The low-temperature resistant vehicle brake fluid according to claim 1, characterized in that, Its wet equilibrium reflux boiling point is 180-186℃.

4. The low-temperature resistant vehicle brake fluid according to claim 1, characterized in that, Its kinematic viscosity at -40℃ is 728-750 mm. 2 / s.

5. The low-temperature resistant vehicle brake fluid according to claim 1, characterized in that, The antioxidant is at least one of 4-methyl-2,6-di-tert-butylphenol, dialkyldiphenylamine, and octylbutyldiphenylamine.

6. The low-temperature resistant vehicle brake fluid according to claim 1, characterized in that, The organic acid is at least one of ricinoleic acid, tartaric acid, and lactic acid.

7. The low-temperature resistant vehicle brake fluid according to claim 1, characterized in that, The pH adjuster is triethanolamine and / or methyldiethanolamine.

8. The low-temperature resistant vehicle brake fluid according to claim 1, characterized in that, The generation of terminal amino polyamide amines is 2.0-4.

0.

9. A method for preparing a low-temperature resistant vehicle brake fluid as described in any one of claims 1-8, characterized in that, Includes the following steps: S1. Add boric acid to the solvent and stir evenly. Add polydimethylsiloxane diol to it and reflux at 70-80℃ for 1-2 hours. Reduce the temperature to 50-60℃, add silane coupling agent and amino-terminated polyamide amine and continue stirring for 1-2 hours. Cool to room temperature to obtain the self-healing modifier. S2. Mix polyethylene glycol borate, triethylene glycol methyl ether borate, diethylene glycol butyl ether, triethylene glycol, 1,4-butanediol, ethylene glycol, and dipropylene glycol monomethyl ether evenly, and stir at 70-80℃ for 10-20 minutes to obtain the preform. S3. Add the self-healing modifier to the preform under stirring, stir for 5-10 minutes, add the antioxidant and organic acid and stir for 1-3 minutes, then add the pH adjuster and stir evenly, and filter.

10. The application of the low-temperature resistant vehicle brake fluid as described in any one of claims 1-8 as an automotive brake fluid.

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