Preparation method of high-performance fluorine-based coolant

Abstract

This invention discloses a method for preparing a high-performance fluorine-based coolant, comprising the following steps: mixing perfluoropolyether, fluorinated alkyl acrylate, and fluorinated cycloalkanes in a certain proportion to obtain a fluorine-based main raw material, drying it, and then adding it to a reaction vessel equipped with a constant temperature device and a high-speed stirrer for dispersion treatment; sequentially adding a composite thermal conductivity enhancer, a radiation stabilizer, a compatibility modifier, and an antioxidant to the reaction vessel, and stirring the reaction; cooling and aging, filtering and purifying, and testing its performance; the fluorine-based coolant is obtained after passing the test. The main system is constructed using perfluoropolyether, fluorinated alkyl acrylate, and fluorinated cycloalkanes, and a compatibility modifier is introduced. The synergistic effect of the composite thermal conductivity enhancer and the radiation stabilizer endows the product with excellent comprehensive performance, with a thermal conductivity exceeding 0.7 W / (m·K), wide temperature range adaptability (-60℃ to 200℃), and excellent radiation resistance (performance retention rate ≥95% after gamma ray irradiation).

Description

Technical Field

[0001] This invention relates to the field of coolant technology, and more specifically to a method for preparing a high-performance fluorine-based coolant. Background Technology

[0002] Fluorine-based coolants have always held an important position and have been widely used in fields with stringent requirements for coolant performance, such as aerospace, electronics, and high-precision machinery, due to their excellent chemical stability, high temperature resistance, insulation, and low surface tension.

[0003] With the rapid development of technology, high-end equipment is constantly moving towards higher power, miniaturization, and integration. This trend has significantly increased the heat density generated by equipment during operation, thus placing more stringent demands on the performance of coolants. Specifically, coolants are required to have a wider range of high and low temperature resistance to adapt to temperature changes under different operating conditions; they also need to have stronger anti-aging properties to ensure performance stability during long-term use; at the same time, higher heat exchange efficiency is also a key requirement to quickly remove the large amount of heat generated by the equipment; in addition, environmental protection and safety are receiving increasing attention, requiring coolants to minimize harm to the environment and human health during production, use, and disposal.

[0004] However, existing methods for preparing fluorine-based coolants have many obvious shortcomings and are difficult to meet the aforementioned new requirements:

[0005] 1. The Challenge of Balancing Performance and Cooling: Some manufacturing processes use only a single fluorocarbon raw material. This single-component design makes it difficult to simultaneously guarantee the thermal conductivity and low-temperature resistance of the coolant. In extreme low-temperature environments, the coolant is prone to problems such as a sudden increase in viscosity and a significant decrease in fluidity, which seriously affects its cooling effect and fails to provide stable and reliable heat dissipation support for equipment.

[0006] 2. Compatibility and stability issues: The various additives used in the preparation process have poor compatibility with the fluorine-based main material. This problem easily leads to phenomena such as stratification and precipitation, which not only reduces the heat dissipation efficiency of the coolant but also shortens its service life, making it difficult to guarantee the long-term stability of the coolant.

[0007] 3. Energy Consumption and Environmental Drawbacks: Some preparation processes require high-temperature and high-pressure reaction conditions, which not only significantly increases energy consumption during production but also places more stringent demands on production equipment, raising production costs. More importantly, the high-temperature and high-pressure environment may cause fluorine-based materials to decompose, producing harmful byproducts, which does not meet current green and environmentally friendly development requirements and poses a potential threat to the environment.

[0008] 4. Weak radiation resistance: Fluorine-based coolants prepared using existing methods generally exhibit weak radiation resistance. In specialized fields involving radiation, such as the nuclear industry and space exploration, the performance of coolants is easily affected by radiation and degrades, significantly limiting the application of fluorine-based coolants in these critical areas.

[0009] Therefore, developing a method for preparing high-performance fluorine-based coolants with mild process conditions, low energy consumption, and excellent product performance that meets environmental and safety standards has become a pressing technical challenge in this field, and is of great significance for promoting the development of related fields. Summary of the Invention

[0010] To address the above-mentioned technical problems, this invention provides a method for preparing a high-performance fluorine-based coolant. This method is mild, simple to operate, and has low energy consumption. It can produce fluorine-based coolants with excellent thermal conductivity, wide temperature range adaptability, long-term stability, radiation resistance, and environmental safety, meeting the complex cooling requirements of high-end equipment.

[0011] The technical solution is as follows:

[0012] A method for preparing a high-performance fluorine-based coolant, the key points of which include the following steps:

[0013] S1: Raw material pretreatment: Perfluoropolyether, fluorinated alkyl acrylate and fluorinated cycloalkanes are mixed in proportion to obtain fluorine-based main raw material, and the fluorine-based main raw material is dried.

[0014] S2: Pre-dispersion: The dried fluorine-based main raw material from step S1 is added to a reactor equipped with a constant temperature device and a high-speed stirrer for dispersion treatment;

[0015] S3: Addition and reaction of functional additives: Add composite thermal conductivity enhancer, radiation stabilizer, compatibility modifier and antioxidant to the reaction vessel in sequence, and stir to react;

[0016] S4: Cooling and ripening: After the reaction is complete, turn off the heating device and allow the mixture to cool down naturally and ripen at a constant temperature.

[0017] S5: Filtration and purification: The matured mixture from step S4 is filtered to obtain coolant;

[0018] S6: Finished Product Inspection: The coolant undergoes performance testing. Once the test is passed, it becomes a fluorine-based coolant.

[0019] Further: the number average molecular weight of the polyether in step S1 is 1000-3000, the fluorinated alkyl acrylate includes perfluorooctyl acrylate or perfluorohexyl acrylate, and the fluorinated cycloalkanes are fluorinated cyclohexane or fluorinated cyclopentane.

[0020] The fluorine-based main raw material is obtained by mixing perfluoropolyether, fluorinated alkyl acrylate and fluorinated cycloalkanes in a mass ratio of 5:3:2.

[0021] Further: In step S1, the mixed fluorine-based main raw material is placed in a vacuum drying oven and dried for 2-3 hours at a temperature of 80-100℃ and a vacuum degree of -0.08-0.1MPa.

[0022] Further: In step S2, the pretreated fluorine-based main raw material is added to a reactor equipped with a constant temperature device and a high-speed stirrer, the temperature is raised to 60-70°C, the stirrer is turned on, and the mixture is stirred at a rate of 300-400 r / min for 15-20 min, while nitrogen gas is introduced into the reactor for inert protection.

[0023] Furthermore: the composite thermal conductivity enhancer is composed of nano-fluorinated graphene and fluorinated alumina in a mass ratio of 2:1, and both nano-fluorinated graphene and fluorinated alumina have undergone perfluorooctyltriethoxysilane surface modification treatment.

[0024] The radiation stabilizer includes potassium perfluorobutyl sulfonate or sodium perfluorohexyl sulfonate, the compatibility modifier is perfluoropolyether amide, and the antioxidant is a hindered phenolic antioxidant.

[0025] Furthermore: the mass of the composite thermal conductivity enhancer is 4%-8% of the mass of the fluorine-based main raw material;

[0026] The mass of the radiation stabilizer is 2%-5% of the mass of the fluorine-based main raw material;

[0027] The mass of the compatibility modifier is 1%-3% of the mass of the fluorine-based main raw material;

[0028] The antioxidant is 0.5-1.5% of the mass of the fluorine-based main raw material.

[0029] Further: In step S3, the functional additives are added to the reactor sequentially under nitrogen protection. After addition, the stirring rate in the reactor is controlled at 500-600 r / min, the temperature is raised to 90-100℃, and the reaction is carried out at a constant temperature for 3-4 hours.

[0030] Further: After the reaction in step S4 is completed, turn off the heating device, maintain the stirring rate at 200-300 r / min, allow it to cool naturally to below 40°C, stop stirring, turn off the nitrogen gas supply device, seal the reactor, and allow it to mature at a constant temperature for 2-3 hours to allow all components to fully fuse.

[0031] Further: In step S5, the mixture is filtered in two stages, passing through a 5μm precision filter and a 0.22μm ultrafiltration membrane in sequence;

[0032] Both filtration processes are carried out under nitrogen protection.

[0033] Further: the test indicators in step S6 are thermal conductivity (25℃) ≥0.7W / (m·K), freezing point ≤-60℃, boiling point ≥200℃, viscosity at 25℃ ≤15mPa·s, performance retention rate ≥95% after irradiation with 10kGy gamma rays, and no stratification or precipitation after standing at room temperature for 12 months.

[0034] Compared with the prior art, the beneficial effects of this invention are as follows: the main system is constructed by perfluoropolyether, fluorinated alkyl acrylate and fluorinated cycloalkanes, and perfluoropolyether amide is innovatively introduced as a compatibility modifier. With the synergistic effect of composite thermal conductivity enhancer and radiation stabilizer, the product is endowed with excellent comprehensive performance. Its thermal conductivity exceeds 0.7 W / (m·K), and it has wide temperature range adaptability (-60℃ to 200℃) and excellent radiation resistance (performance retention rate ≥95% after gamma ray irradiation).

[0035] During the preparation process, by using vacuum drying pretreatment, nitrogen inert protection throughout the process, and precise segmented temperature and rate control (60-100℃ atmospheric pressure reaction), the problems of poor component compatibility, easy stratification and precipitation, and high-temperature degradation of traditional fluorine-based materials are effectively solved, achieving a balance between high purity and high stability. This solution is not only simple and controllable to operate, with low energy consumption and easy to scale up industrially, but also uses environmentally friendly and low-toxic raw materials and produces no harmful byproducts during the preparation process, meeting green and safe standards and having extremely high value for promotion and application. Attached Figure Description

[0036] Figure 1 This is a comparison of test results between the examples and existing technologies. Detailed Implementation

[0037] The present invention will be further described below with reference to the embodiments.

[0038] A method for preparing a high-performance fluorine-based coolant includes the following steps:

[0039] S1: Raw material pretreatment: Perfluoropolyether, fluorinated alkyl acrylate and fluorinated cycloalkanes are mixed in a mass ratio of 5:3:2 to obtain fluorine-based main raw material;

[0040] The perfluoropolyether has a number-average molecular weight of 1000-3000. This molecular weight range can ensure the insulation performance of the coolant while taking into account its viscosity characteristics, thus ensuring good fluidity.

[0041] Fluorinated alkyl acrylates can be selected from perfluorooctyl acrylate or perfluorohexyl acrylate, whose fluorinated groups in their molecular structure help to improve the chemical stability of the coolant and its compatibility with other fluorinated raw materials;

[0042] Fluorinated cycloalkanes, such as fluorocyclohexane or fluorocyclopentane, enhance the thermal conductivity of coolants by utilizing their close molecular arrangement and high phonon transfer efficiency.

[0043] By rationally adjusting the ratio of perfluoropolyether, fluorinated alkyl acrylate and fluorinated cycloalkanes, the three components can work synergistically to fully leverage their respective advantages, laying the foundation for the excellent performance of the coolant.

[0044] The mixed fluorine-based main raw material is placed in a vacuum drying oven and dried for 2-3 hours at a temperature of 80-100℃ and a vacuum degree of -0.08-0.1MPa. The vacuum environment can effectively lower the boiling point of water and accelerate the evaporation of water in the raw material, while preventing impurities in the air from entering the raw material. Reasonable temperature and time settings can thoroughly remove water and volatile impurities from the raw material while preventing the raw material from decomposing or changing its properties due to overheating, ensuring the smooth progress of subsequent reactions and the stability of product quality.

[0045] S2: Pre-dispersion: The pretreated fluorine-based main raw material is added to a reactor equipped with a thermostat and a high-speed stirrer. The thermostat is activated to raise the temperature inside the reactor to 60-70℃. This temperature range ensures good fluidity of the fluorine-based main raw material, facilitating subsequent dispersion operations. The stirrer is then turned on and stirred at a rate of 300-400 r / min for 15-20 min. During this process, nitrogen gas is simultaneously introduced into the reactor for inert protection. Nitrogen gas isolates the raw material from air, preventing oxidation reactions with oxygen in the air during stirring, avoiding the introduction of impurities, and ensuring the purity of the raw material and the stability of subsequent reactions. Pre-dispersion ensures that the fluorine-based main raw material is evenly distributed within the reactor, creating favorable conditions for the subsequent addition of functional additives and the reaction.

[0046] S3: Functional Additive Addition and Reaction: Add the composite thermal conductivity enhancer, radiation stabilizer, compatibility modifier, and antioxidant sequentially to the reactor. Control the stirring rate at 500-600 r / min to promote thorough mixing and reaction between the functional additives and the fluorine-based main raw material. Raise the temperature to 90-100℃. Under these conditions, the reactivity between the components is enhanced, allowing for a complete chemical reaction and the formation of a stable system. Maintain this temperature and stirring rate for a constant-temperature reaction of 3-4 hours to ensure complete reaction. This allows the functional additives to disperse uniformly and form a tight bond with the fluorine-based main raw material, thereby imparting excellent comprehensive properties to the coolant.

[0047] The composite thermal conductivity enhancer is composed of nano-fluorinated graphene and fluorinated alumina in a mass ratio of 2:1. The nano-fluorinated graphene has a particle size of 10-20 nm, and the fluorinated alumina has a particle size of 20-30 nm. Nanomaterials in this particle size range have a large specific surface area, which can significantly increase the contact area with the fluorine-based main raw material and enhance the thermal conductivity. At the same time, both the nano-fluorinated graphene and the fluorinated alumina have undergone perfluorooctyltriethoxysilane surface modification treatment. The compatibility of the surface-modified composite thermal conductivity enhancer with the fluorine-based main raw material is greatly improved, effectively avoiding agglomeration caused by poor compatibility, ensuring that it can be uniformly dispersed in the fluorine-based main body and give full play to its thermal conductivity enhancement effect.

[0048] The radiation stabilizer is potassium perfluorobutyl sulfonate or sodium perfluorohexyl sulfonate. These substances have good radiation resistance properties, can exist stably in a radiation environment, and can effectively capture free radicals generated by radiation, reducing the damage of radiation to the molecular structure of the coolant, thereby improving the radiation resistance of the coolant.

[0049] The compatibility modifier is a perfluoropolyether amide. The molecular structure of perfluoropolyether amide contains both fluorocarbon segments similar to perfluoropolyether and amide groups that can interact with other additives. This special structure enables it to act as a bridge between the fluorine-based main raw material and other functional additives, effectively improving the compatibility between the components, preventing the coolant from stratifying and precipitating during long-term storage and use, and improving the long-term stability of the coolant.

[0050] The antioxidant is a hindered phenolic antioxidant, specifically 2,6-di-tert-butyl-p-cresol or pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]. Hindered phenolic antioxidants can effectively inhibit the oxidation reaction of coolant during storage and use, capture free radicals generated by oxidation, delay the aging process of coolant, and extend its service life.

[0051] The dosages of various functional additives are as follows:

[0052] The amount of composite thermal conductivity enhancer added is 4%-8% of the mass of the fluorine-based main raw material. By controlling the amount of this composite thermal conductivity enhancer added, the viscosity of the coolant can be increased and its fluidity affected by excessive addition, while ensuring a significant improvement in thermal conductivity.

[0053] The amount of radiation stabilizer added is 2%-5% of the mass of the fluorine-based main raw material. The amount of this radiation stabilizer added can enable the coolant to retain more than 95% of its performance after being irradiated by 10kGy gamma rays, meeting the requirements for use in special radiation environments.

[0054] The amount of compatibility modifier added is 1%-3% of the mass of the fluorine-based main raw material. Adding an appropriate amount of compatibility modifier can achieve a good compatibility adjustment effect, while adding too much may increase production costs and have an adverse effect on other properties of the coolant.

[0055] The amount of antioxidant added is 0.5%-1.5% of the mass of the fluorine-based main raw material. This amount of antioxidant can ensure good antioxidant effect while avoiding changes in coolant performance due to excessive antioxidant.

[0056] S4: Cooling and ripening: After the reaction is complete, turn off the heating device and stop heating. Maintain a stirring rate of 200-300 r / min. This stirring rate can ensure that the mixture cools down evenly and prevent the components from separating due to the stirring rate being too low.

[0057] Allow the mixture to cool naturally in the reactor. Once the temperature drops below 40°C, stop stirring, seal the reactor, and maintain the temperature for 2-3 hours. This constant-temperature maturation process allows sufficient time for the components in the mixture to fully integrate, resulting in more stable intermolecular forces. This improves the performance stability and uniformity of the coolant, ensuring the quality of the final product.

[0058] S5: Purification and Filtration: The matured mixture is purified by filtration. The filtration process uses a two-stage filtration method.

[0059] First, the mixture is passed through a 5μm precision filter to remove larger unreacted impurities and agglomerated particles. Then, it is passed through a 0.22μm ultrafiltration membrane to further remove tiny particulate impurities and molecular-level impurities, ensuring the purity of the coolant.

[0060] Throughout the two-stage filtration process, nitrogen protection is employed to prevent oxidation of the coolant upon contact with air during filtration, thus avoiding the introduction of new impurities and ensuring the purity and performance stability of the coolant. This filtration purification process significantly improves the purity of the coolant, reduces the impact of impurities on its performance, and ensures that the final product meets high-performance requirements.

[0061] S6: Finished Product Inspection: The filtered coolant is subjected to performance testing, including thermal conductivity, freezing point, boiling point, viscosity, radiation resistance and stability. Once the test is passed, it is a high-performance fluorine-based coolant.

[0062] Among them, thermal conductivity: at an ambient temperature of 25℃, the thermal conductivity of the coolant is tested using a thermal conductivity meter. The thermal conductivity is required to be ≥0.7W / (m·K) to ensure that the coolant has good heat exchange efficiency and can quickly remove the heat generated by the equipment.

[0063] High and low temperature resistance: The freezing point and boiling point of the coolant are tested by a freezing point tester and a boiling point tester, respectively. The requirements are that the freezing point is ≤-60℃ and the boiling point is ≥200℃, so as to ensure that the coolant can maintain good fluidity and stability under extreme high and low temperature environments and perform its cooling function normally.

[0064] Viscosity: The viscosity of the coolant is tested using a viscometer at 25°C. The viscosity should be ≤15 mPa·s. Lower viscosity helps the coolant flow smoothly in the cooling system, improves heat dissipation efficiency, and reduces energy consumption.

[0065] Radiation resistance performance: The coolant is placed in a 10kGy gamma ray radiation environment for radiation treatment. After the radiation is completed, its various performance indicators are tested and compared with the performance indicators before radiation. The performance retention rate is calculated and the performance retention rate is required to be ≥95% to ensure that the coolant can work stably in the radiation environment.

[0066] Long-term stability: The coolant is placed in a static environment at room temperature and stored for 12 months. The coolant is observed to see if there is any stratification or sedimentation. It is required that there is no stratification or sedimentation after standing at room temperature for 12 months to ensure the performance stability of the coolant during long-term storage and use.

[0067] If all the above performance tests are passed, the coolant is a qualified high-performance fluorine-based coolant. If any test indicator fails to meet the requirements, the process of preparation must be re-examined, the problem identified and adjusted, and the product must be re-prepared and tested again until it is qualified.

[0068] This invention constructs a fluorine-based main system using perfluoropolyether, fluorinated alkyl acrylate, and fluorinated cycloalkanes, and innovatively introduces perfluoropolyether amide as a compatibility modifier. Simultaneously, the synergistic effect of composite thermal conductivity enhancers and radiation stabilizers results in a fluorine-based coolant with superior comprehensive performance. Its thermal conductivity exceeds 0.7 W / (m·K), enabling rapid and efficient heat transfer to meet the heat dissipation requirements of high-power equipment. It possesses wide temperature range adaptability, operating stably within a temperature range of -60℃ to 200℃, adapting to various extreme environmental conditions. It exhibits excellent radiation resistance, retaining ≥95% of its performance after irradiation with 10 kGy gamma rays, allowing reliable operation in special radiation environments such as nuclear industry and space exploration. Furthermore, it demonstrates excellent long-term stability, showing no stratification or precipitation after 12 months of standing at room temperature, ensuring the long-term effective use of the coolant.

[0069] During the preparation process, a series of optimization measures effectively solved many problems encountered in the traditional preparation of fluorine-based materials. First, the vacuum drying pretreatment step thoroughly removes moisture and volatile impurities from the raw materials, providing a pure raw material environment for subsequent reactions. Second, nitrogen inert protection throughout the process, including pre-dispersion, functional agent reaction, and filtration purification, effectively isolates the raw materials from air, preventing oxidation reactions and avoiding the introduction of impurities. Third, the precise segmented temperature and rate control design (reaction temperature controlled within the atmospheric pressure reaction range of 60-100℃) not only reduces the equipment requirements and avoids the problem of easy decomposition of fluorine-based materials under high temperature and high pressure conditions, but also reduces energy consumption and production costs. Through these process optimizations, a balance between high purity and high stability of the fluorine-based coolant is achieved.

[0070] The raw materials selected in this invention are all low-toxicity and environmentally friendly fluorine-based compounds. No harmful byproducts are generated during the entire preparation process, and the finished product contains no toxic volatile components, meeting current stringent environmental and safety standards. It will not cause harm to the environment or human health during use, satisfying the requirements of green production and use. Furthermore, the preparation method is simple and controllable, with each process parameter (temperature, stirring rate, reaction time, etc.) easily and precisely controlled. The product exhibits good repeatability and can stably prepare high-performance fluorine-based coolants, facilitating industrial-scale production. It has extremely high application value and can provide strong technical support for the development of related fields such as aerospace, electronics, and nuclear industry.

[0071] Example 1

[0072] A method for preparing a high-performance fluorine-based coolant includes the following steps:

[0073] S1: Raw material pretreatment: Add 50 kg of perfluoropolyether (number average molecular weight 2000), 30 kg of perfluorooctyl acrylate, and 20 kg of fluorocyclohexane to a mixing container and mix thoroughly using a stirring device for 30 minutes to ensure uniform mixing of the three raw materials, thus obtaining the fluorine-based main raw material; place the uniformly mixed fluorine-based main raw material in a vacuum drying oven and dry it for 2.5 hours at a temperature of 90℃ and a vacuum degree of -0.09MPa.

[0074] During the drying process, regularly observe the conditions inside the vacuum drying oven to ensure the drying process proceeds normally and thoroughly removes moisture and volatile impurities from the raw materials. After drying is complete, wait for the temperature inside the vacuum drying oven to drop to room temperature before removing the fluorine-based main raw material for later use.

[0075] S2: Pre-dispersion: The pretreated fluorine-based main raw material is added to a reactor equipped with a thermostat and a high-speed stirrer. The reactor inlet is closed, and the thermostat is activated to slowly raise the temperature inside the reactor to 65°C at a rate of 5°C / min to avoid local overheating of the raw material due to rapid heating. Once the temperature reaches 65°C, the high-speed stirrer is turned on, and the stirring speed is adjusted to 350 r / min to stir the fluorine-based main raw material for 18 min. Simultaneously with the start of stirring, nitrogen gas is introduced into the reactor at a rate of 0.5 L / min to ensure the reactor is filled with nitrogen, creating an inert protective atmosphere to prevent oxidation of the raw material upon contact with air.

[0076] S3: Functional additives addition and reaction: Accurately weigh 6 kg of composite thermal conductivity enhancer (4 kg of nano-fluorinated graphene and 2 kg of fluorinated alumina, both modified by perfluorooctyltriethoxysilane), 3 kg of potassium perfluorobutylsulfonate, 2 kg of perfluoropolyether amide, and 1 kg of 2,6-di-tert-butyl-p-cresol;

[0077] Under conditions of maintaining the reactor temperature at 65℃, stirring speed at 350 r / min, and continuous nitrogen flow, the composite thermal conductivity enhancer was first slowly added to the reactor over a period of 10 minutes. During this process, the state of the mixture in the reactor was closely observed to ensure that the composite thermal conductivity enhancer was uniformly dispersed and free from agglomeration. After the composite thermal conductivity enhancer was added, stirring continued for 15 minutes to ensure thorough mixing between the composite thermal conductivity enhancer and the fluorine-based main raw material.

[0078] Next, potassium perfluorobutyl sulfonate was slowly added to the reaction vessel over a period of 5 minutes. After the addition was complete, the mixture was stirred for 10 minutes to promote the integration of potassium perfluorobutyl sulfonate with the mixture.

[0079] Then, add perfluoropolyether amide for 5 minutes and stir for 10 minutes to improve the compatibility between the components.

[0080] Finally, 2,6-di-tert-butyl-p-cresol was added over 3 minutes. After addition, the stirrer speed was increased to 550 rpm, and the temperature inside the reactor was simultaneously raised to 95°C at a rate of 3°C / min using a thermostat. Once the temperature reached 95°C, this temperature and stirring speed were maintained for a constant-temperature reaction for 3.5 hours. During the reaction, samples were taken every 30 minutes, and the microstructure of the mixture was observed under a microscope to ensure the reaction proceeded normally and that all components were uniformly dispersed.

[0081] S4: Cooling and Curing: After the reaction is complete, turn off the heating device of the reactor and stop heating. Maintain the stirrer speed at 250 r / min and allow the mixture to cool naturally in the reactor. During the cooling process, record the temperature inside the reactor every 15 minutes. When the temperature drops to 38℃, stop stirring. Turn off the nitrogen gas supply device, seal the reactor, and perform constant temperature curing treatment for 2.5 hours. During the curing process, maintain the temperature inside the reactor at around 38℃ to ensure that the components have sufficient time to fully integrate.

[0082] S5: Purification and Filtration: After maturation, open the reactor outlet and introduce the matured mixture into a filtration system equipped with a nitrogen protection device. First, turn on the nitrogen protection device and introduce nitrogen into the filtration system, controlling the nitrogen pressure at 0.2 MPa to ensure the filtration process is carried out under a nitrogen atmosphere. Then, send the mixture to a 5μm precision filter for the first filtration, controlling the filtration rate at 10 L / h to remove larger particles of impurities from the mixture. After the first filtration, collect the filtrate and send it to a 0.22μm ultrafiltration membrane for a second filtration, controlling the filtration rate at 5 L / h to further remove tiny particles and molecular-level impurities.

[0083] During the filtration process, the working status of the filter and ultrafiltration membrane should be checked regularly to prevent clogging and ensure smooth filtration. The filtrate after the two filtrations is collected, which is the pre-purified coolant.

[0084] S6: Finished Product Inspection: Conduct comprehensive performance tests on the purified and filtered coolant. The test methods and results are as follows:

[0085] Thermal conductivity test: The thermal conductivity of the coolant was tested using a laser flash thermal conductivity meter at an ambient temperature of 25℃. The test result was a thermal conductivity of 0.75W / (m·K), which meets the requirement of ≥0.7W / (m·K).

[0086] Freezing point test: Using a freezing method freezing point tester, the coolant is placed in a low temperature environment and the temperature is gradually lowered. The temperature at which the coolant begins to freeze is observed. The test result is a freezing point of -65℃, which meets the standard of ≤-60℃.

[0087] Boiling point test: The coolant was heated and distilled using an atmospheric pressure distillation boiling point tester. The temperature at which the coolant began to boil was recorded. The test result was a boiling point of 210℃, which meets the requirement of ≥200℃.

[0088] Viscosity test: The viscosity of the coolant was measured using a rotational viscometer at 25°C. The result was 12 mPa·s, which meets the requirement of ≤15 mPa·s.

[0089] Radiation resistance performance testing: The coolant sample was placed in a gamma-ray radiation device and irradiated at a dose of 10 kGy. After irradiation, the thermal conductivity, viscosity, freezing point, boiling point, and other performance indicators of the coolant were measured and compared with those before irradiation to calculate the performance retention rate. The test results showed that after irradiation with 10 kGy gamma rays, the changes in various performance indicators of the coolant were minimal, and the performance retention rate was 97%, meeting the requirement of ≥95%.

[0090] Long-term stability test: A certain amount of coolant sample was taken and placed in a sealed container, and stored at room temperature (around 25℃) for 12 months. During the storage period, the state of the coolant was observed every month to check for stratification or precipitation. After 12 months, the coolant remained uniform and transparent, with no stratification or precipitation, meeting the long-term stability requirements.

[0091] After all the above tests, the coolant met the requirements for high-performance fluorine-based coolants and was determined to be a qualified product.

[0092] Example 2

[0093] A method for preparing a high-performance fluorine-based coolant includes the following steps:

[0094] S1: Raw material pretreatment: Add 50 kg of perfluoropolyether (number average molecular weight 1500), 30 kg of perfluorohexyl acrylate, and 20 kg of fluorocyclopentane to a mixing tank, and stir with a paddle stirrer at a speed of 200 r / min for 40 min to ensure that the raw materials are fully mixed and to obtain the fluorine-based main raw material.

[0095] The fluorine-based raw material was placed in a vacuum drying oven, and the temperature was set to 85℃ and the vacuum degree to -0.085MPa for 2 hours. During the drying process, the vacuum degree and temperature were recorded every 30 minutes to ensure parameter stability. After drying, the material was allowed to cool to room temperature before being taken out for use.

[0096] S2: Pre-dispersion: Add the pretreated fluorine-based main raw material to a reactor equipped with a thermostat and a high-speed stirrer, and close the reactor lid; start the thermostat system and heat to 62°C at a rate of 4°C / min. Turn on the stirrer and adjust it to 320 r / min for 16 min, while simultaneously introducing nitrogen gas at a rate of 0.4 L / min to create an inert environment and prevent oxidation of the raw material.

[0097] S3: Functional additives addition and reaction: Weigh 4 kg of composite thermal conductivity enhancer (8 / 3 kg of nano-fluorinated graphene and 4 / 3 kg of fluorinated alumina, both modified by perfluorooctyltriethoxysilane), 2 kg of sodium perfluorohexyl sulfonate, 1 kg of perfluoropolyether amide, and 0.8 kg of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid];

[0098] Under nitrogen protection and stirring at 62℃ and 320 rpm, the composite thermal conductivity enhancer was first slowly added (completed over 12 min), followed by stirring for 20 min; then sodium perfluorohexyl sulfonate was added (completed over 6 min), followed by stirring for 15 min; next, perfluoropolyether amide was added (completed over 4 min), followed by stirring for 12 min; finally, the antioxidant was added (completed over 3 min). The stirring rate was then increased to 500 rpm, and the temperature was raised to 92℃ at a rate of 2℃ / min, and the reaction was maintained at this temperature for 3 h. Samples were taken every 40 min to observe the microstructure during the reaction.

[0099] S4: Cooling and Curing: After the reaction is complete, turn off the heating, maintain stirring at 220 rpm, and allow it to cool naturally. When the temperature drops to 35℃, stop stirring, seal the reactor, and cure at a constant temperature for 2 hours to ensure that the components are fully integrated.

[0100] S5: After purification, filtration and maturation, under nitrogen protection at 0.18MPa, the mixture is passed through a 5μm precision filter at a rate of 8L / h, and then through a 0.22μm ultrafiltration membrane at a rate of 4L / h, and the filtrate is collected.

[0101] Regularly check the membrane integrity during filtration to prevent leakage.

[0102] S6: Finished product inspection: The test results are as follows: thermal conductivity 0.72W / (m·K), freezing point -62℃, boiling point 205℃, viscosity at 25℃ 13mPa·s, performance retention rate 96% after irradiation with 10kGy gamma rays, no stratification or precipitation after standing at room temperature for 12 months, which meets the requirements.

[0103] Example 3

[0104] A method for preparing a high-performance fluorine-based coolant includes the following steps:

[0105] S1: Raw material pretreatment: Add 50 kg of perfluoropolyether (number average molecular weight 2500), 30 kg of perfluorooctyl acrylate, and 20 kg of fluorocyclohexane to a mixing tank, and stir with a paddle stirrer at a speed of 250 r / min for 35 min to ensure that the raw materials are fully mixed and to obtain the fluorine-based main raw material.

[0106] Place it in a vacuum drying oven and dry it for 3 hours at a temperature of 95℃ and a vacuum of -0.095MPa. Monitor the parameters every 20 minutes during drying to ensure they are normal. Remove it for later use after cooling.

[0107] S2: Pre-dispersion: Add the pretreated fluorine-based main raw material to the reactor, heat to 68℃ (heating rate 6℃ / min), turn on the stirrer and stir at a rate of 380r / min for 20min, while simultaneously introducing nitrogen gas at 0.6-0.6L / min for inert protection;

[0108] S3: Functional additives addition and reaction: Weigh 8 kg of composite thermal conductivity enhancer (16 / 3 kg of nano-fluorinated graphene, 8 / 3 kg of fluorinated alumina, after modification), 5 kg of potassium perfluorobutyl sulfonate, 3 kg of perfluoropolyether amide, and 1.5 kg of 2,6-di-tert-butyl-p-cresol.

[0109] Under nitrogen protection and stirring at 68℃ and 380 rpm, the following additives were added sequentially: composite thermal conductivity enhancer added over 15 min with stirring for 25 min; potassium perfluorobutyl sulfonate added over 8 min with stirring for 18 min; perfluoropolyether amide added over 7 min with stirring for 15 min; and antioxidant added over 5 min. The stirring rate was then increased to 600 rpm, and the temperature was raised to 98℃ (heating rate 4℃ / min), and the reaction was maintained at this temperature for 4 h. Samples were taken every 30 min during the reaction.

[0110] S4: Cooling and maturation: After the reaction is complete, keep the stirring rate at 280 r / min and let it cool naturally to 39℃, then keep it at a constant temperature for 3 hours.

[0111] S5: Purification and Filtration: Under nitrogen protection at 0.22 MPa, the mixture is passed through a 5 μm filter at a rate of 12 L / h, and then through a 0.22 μm ultrafiltration membrane at a rate of 6 L / h. The filtrate is then collected.

[0112] S6: Finished product inspection: The test results are as follows: thermal conductivity 0.78W / (m·K), freezing point -68℃, boiling point 215℃, viscosity at 25℃ 11mPa·s, performance retention rate 98% after irradiation with 10kGy gamma rays, no stratification or precipitation after standing at room temperature for 12 months, which meets the requirements.

[0113] Comparative Example

[0114] Comparative Example 1

[0115] To verify the performance difference between the fluorine-based coolant prepared by the existing preparation method and the fluorine-based coolant prepared by the present invention, performance tests were conducted on the fluorine-based coolant prepared by the existing method. The test items, methods, and standards were consistent with the product test results in Example 1.

[0116] The specific test results are as follows: thermal conductivity 0.55W / (m·K), freezing point -45℃, boiling point 180℃, viscosity at 25℃ 20mPa·s, performance retention rate 85% after irradiation with 10kGy gamma rays, and slight stratification after standing at room temperature for 12 months.

[0117] like Figure 1 As shown, a performance comparison is made between fluorine-based coolants prepared by existing methods and those prepared by the method provided in this invention. The fluorine-based coolant prepared by this invention exhibits significant advantages in all performance indicators.

[0118] A higher thermal conductivity indicates stronger heat exchange efficiency; a lower freezing point and a higher boiling point indicate a wider range of high and low temperature resistance and stronger environmental adaptability; lower viscosity at 25℃ means better fluidity and less heat dissipation resistance; higher performance retention after 10kGy gamma ray irradiation, demonstrating superior radiation resistance; no stratification after 12 months of standing at room temperature, while products prepared by existing methods show slight stratification, proving that the product of this invention has superior long-term stability. This comparison table fully verifies the superiority of the preparation method of this invention and the high performance of the prepared fluorine-based coolant.

[0119] Comparative Example 2

[0120] To verify the importance of surface modification treatment in composite thermal conductivity enhancers, Comparative Example 2 was set up, and the specific steps are as follows:

[0121] S1-S2: Raw material pretreatment and predispersion

[0122] The operating steps are exactly the same as in Example 1 to ensure consistency in raw material pretreatment and pre-dispersion processes and to eliminate interference from other factors on the experimental results.

[0123] S3: Functional Additives Addition and Reaction

[0124] The composite thermal conductivity enhancer was not subjected to perfluorooctyltriethoxysilane surface modification treatment (the other components and dosages were the same as in Example 1: 4 kg of nano-fluorinated graphene and 2 kg of fluorinated alumina). The order of addition, dosage, and reaction conditions (stirring rate, reaction temperature, reaction time, etc.) of the other additives were consistent with those in Example 1.

[0125] S4-S6: Cooling and maturation, purification and filtration, and finished product testing

[0126] The operating steps are exactly the same as in Example 1 to ensure the uniformity of subsequent processing and testing standards, so as to accurately compare the impact of composite thermal conductivity enhancer surface modification treatment on product performance.

[0127] The performance test results of the coolant prepared in Comparative Example 2 are as follows:

[0128] The thermal conductivity is 0.62 W / (m·K), which is significantly lower than 0.75 W / (m·K) in Example 1. This is because the composite thermal conductivity enhancer without surface modification has poor compatibility with the fluorine-based main raw material and is prone to agglomeration, which makes it unable to be uniformly dispersed in the fluorine-based main body and thus cannot fully exert its thermal conductivity enhancement effect.

[0129] The freezing point is -52℃, which is higher than -65℃ in Example 1, and the boiling point is 190℃, which is lower than 210℃ in Example 1. The high and low temperature resistance has decreased, which may be due to the agglomeration of the composite thermal conductivity enhancer affecting the overall molecular structure and interaction of the coolant, thereby changing its phase transition temperature.

[0130] The viscosity at 25°C was 18 mPa·s, which was higher than the 12 mPa·s in Example 1. The increased viscosity and poorer fluidity were due to the agglomerated composite thermal conductivity enhancer forming larger particles in the coolant, which increased the internal frictional resistance of the liquid.

[0131] After irradiation with 10 kGy gamma rays, the performance retention rate was 90%, which was lower than 97% in Example 1. The radiation resistance performance was weakened, which may be due to the agglomeration of the composite thermal conductivity enhancer, which prevented it from exerting a uniform radiation resistance synergistic effect in the radiation environment.

[0132] The product exhibited obvious stratification after standing at room temperature for 12 months, while the product in Example 1 showed no stratification. This fully demonstrates that the composite thermal conductivity enhancer without surface modification treatment has poor compatibility with the fluorine-based main raw material, resulting in poor long-term stability of the coolant.

[0133] By comparing Comparative Example 2 with Example 1, the importance of the composite thermal conductivity enhancer being modified with perfluorooctyltriethoxysilane is clearly demonstrated. This treatment can significantly improve the compatibility of the composite thermal conductivity enhancer with the fluorine-based main raw material, thereby ensuring that the various performance indicators of the coolant meet the high-performance requirements.

[0134] Comparative Example 3

[0135] To further verify the necessity of the key components and process parameters in the preparation method of the present invention, Comparative Example 3 was set up, and the specific steps are as follows:

[0136] S1: Raw material pretreatment

[0137] Only perfluoropolyether (number average molecular weight 2000) was used as the main fluorine-based raw material, without the addition of fluorinated alkyl acrylates and fluorinated cycloalkanes; 50 kg of perfluoropolyether was placed in a vacuum drying oven and dried for 2.5 h at a temperature of 90 °C and a vacuum of -0.09 MPa. The drying operation was the same as in Example 1.

[0138] S2: Predispersed

[0139] The operating steps are exactly the same as in Example 1: heat to 65°C, stir at 350 r / min for 18 min, and purge with nitrogen gas to ensure the consistency of the pre-dispersion process.

[0140] S3: Functional Additives Addition and Reaction

[0141] No compatibility modifier (perfluoropolyether amide) was added. The types, amounts, and order of addition of the other additives (6 kg composite thermal conductivity enhancer, 3 kg potassium perfluorobutyl sulfonate, 1 kg 2,6-di-tert-butyl-p-cresol), as well as the reaction conditions (stirring speed 550 r / min, reaction temperature 95 °C, reaction time 3.5 h) were the same as in Example 1.

[0142] S4-S6: Cooling and maturation, purification and filtration, and finished product testing

[0143] The operating steps are exactly the same as in Example 1 to ensure consistency in subsequent processing and testing, so as to accurately assess the impact of the absence of key components on product performance.

[0144] The performance test results of the fluorine-based coolant prepared in Comparative Example 3 were as follows: thermal conductivity 0.65 W / (m·K), which is lower than 0.75 W / (m·K) in Example 1. This is because the fluorinated cycloalkanes, a component that helps improve thermal conductivity, are missing. Fluorinated cycloalkanes have a tight molecular arrangement and high phonon transfer efficiency, and their absence leads to a decrease in the thermal conductivity of the coolant.

[0145] The freezing point is -48℃, which is higher than -65℃ in Example 1, and the boiling point is 185℃, which is lower than 210℃ in Example 1. The high and low temperature resistance is significantly worse, mainly because the absence of fluorinated alkyl acrylate affects the molecular structure stability and phase change characteristics of the coolant. Fluorinated alkyl acrylate can enhance the chemical stability and temperature resistance of the coolant.

[0146] The viscosity at 25°C is 17 mPa·s, which is higher than 12 mPa·s in Example 1. The viscosity increases and the fluidity decreases. This is because when perfluoropolyether is used alone as the main raw material, its intermolecular forces are relatively strong, and the fluorinated alkyl acrylate lacks the effect of regulating the viscosity of the system.

[0147] After irradiation with 10 kGy gamma rays, the performance retention rate was 92%, which was lower than 97% in Example 1. The radiation resistance performance was weakened, which may be due to the decreased compatibility between the components due to the lack of compatibility modifier, resulting in the radiation stabilizer not being able to play its full role.

[0148] The product exhibited obvious stratification after standing at room temperature for 12 months, while the product in Example 1 did not stratify. This is mainly because no compatibility modifier (perfluoropolyether amide) was added, which resulted in poor compatibility between the functional additives and the fluorine-based main raw material, making it impossible to form a stable system and causing stratification to gradually occur during long-term storage.

[0149] The performance comparison between Comparative Example 3 and Example 1 shows that the key components (fluorinated alkyl acrylate, fluorinated cycloalkanes, and compatibility modifier) ​​in the preparation method of the present invention play a crucial role in the performance of the fluorinated coolant. The lack of any one of the key components will lead to a significant decrease in the performance of the coolant, further verifying the rationality and necessity of the raw material formulation and preparation process of the present invention.

[0150] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention. Those skilled in the art, under the guidance of the present invention, can make various similar representations without departing from the spirit and claims of the present invention, and such modifications all fall within the protection scope of the present invention.

Claims

1. A method for preparing a high-performance fluorine-based coolant, characterized in that: Includes the following steps: S1: Raw material pretreatment: Perfluoropolyether, fluorinated alkyl acrylate and fluorinated cycloalkanes are mixed in proportion to obtain fluorine-based main raw material, and the fluorine-based main raw material is dried. S2: Pre-dispersion: The dried fluorine-based main raw material from step S1 is added to a reactor equipped with a constant temperature device and a high-speed stirrer for dispersion treatment; S3: Addition and reaction of functional additives: Add composite thermal conductivity enhancer, radiation stabilizer, compatibility modifier and antioxidant to the reaction vessel in sequence, and stir to react; S4: Cooling and ripening: After the reaction is complete, turn off the heating device and allow the mixture to cool down naturally and ripen at a constant temperature. S5: Filtration and purification: The matured mixture from step S4 is filtered to obtain coolant; S6: Finished Product Inspection: The coolant undergoes performance testing. Once the test is passed, it becomes a fluorine-based coolant.

2. The method for preparing a high-performance fluorine-based coolant according to claim 1, characterized in that: In step S1, the number average molecular weight of the polyether is 1000-3000, the fluorinated alkyl acrylate includes perfluorooctyl acrylate or perfluorohexyl acrylate, and the fluorinated cycloalkanes are fluorinated cyclohexane or fluorinated cyclopentane. The fluorine-based main raw material is obtained by mixing perfluoropolyether, fluorinated alkyl acrylate and fluorinated cycloalkanes in a mass ratio of 5:3:

2.

3. The method for preparing a high-performance fluorine-based coolant according to claim 2, characterized in that: In step S1, the mixed fluorine-based main raw material is placed in a vacuum drying oven and dried for 2-3 hours at a temperature of 80-100℃ and a vacuum degree of -0.08-0.1MPa.

4. The method for preparing a high-performance fluorine-based coolant according to claim 1, characterized in that: In step S2, the pretreated fluorine-based main raw material is added to a reactor equipped with a constant temperature device and a high-speed stirrer. The temperature is raised to 60-70°C, the stirrer is turned on, and the mixture is stirred at a rate of 300-400 r / min for 15-20 min. At the same time, nitrogen gas is introduced into the reactor for inert protection.

5. A method for preparing a high-performance fluorine-based coolant according to claim 1 or 4, characterized in that: The composite thermal conductivity enhancer is a mixture of nano-fluorinated graphene and fluorinated alumina in a mass ratio of 2:1, and both the nano-fluorinated graphene and the fluorinated alumina have undergone perfluorooctyltriethoxysilane surface modification treatment. The radiation stabilizer includes potassium perfluorobutyl sulfonate or sodium perfluorohexyl sulfonate, the compatibility modifier is perfluoropolyether amide, and the antioxidant is a hindered phenolic antioxidant.

6. The method for preparing a high-performance fluorine-based coolant according to claim 5, characterized in that: The mass of the composite thermal conductivity enhancer is 4%-8% of the mass of the fluorine-based main raw material; The mass of the radiation stabilizer is 2%-5% of the mass of the fluorine-based main raw material; The mass of the compatibility modifier is 1%-3% of the mass of the fluorine-based main raw material; The antioxidant is 0.5-1.5% of the mass of the fluorine-based main raw material.

7. The method for preparing a high-performance fluorine-based coolant according to claim 6, characterized in that: In step S3, the functional additives are added to the reactor sequentially under nitrogen protection. After addition, the stirring rate in the reactor is controlled at 500-600 r / min, the temperature is raised to 90-100℃, and the reaction is carried out at a constant temperature for 3-4 hours.

8. The method for preparing a high-performance fluorine-based coolant according to claim 1, characterized in that: After the reaction in step S4 is completed, turn off the heating device, maintain the stirring rate at 200-300 r / min, allow it to cool naturally to below 40°C, stop stirring, turn off the nitrogen gas supply device, seal the reactor, and allow it to mature at a constant temperature for 2-3 hours to ensure that all components are fully integrated.

9. The method for preparing a high-performance fluorine-based coolant according to claim 8, characterized in that: In step S5, the mixture is filtered in two stages, passing through a 5μm precision filter and a 0.22μm ultrafiltration membrane. Both filtration processes are carried out under nitrogen protection.

10. The method for preparing a high-performance fluorine-based coolant according to claim 9, characterized in that: The test indicators in step S6 are: thermal conductivity (25℃) ≥ 0.7 W / (m·K), freezing point ≤ -60℃, boiling point ≥ 200℃, viscosity at 25℃ ≤ 15 mPa·s, performance retention rate ≥ 95% after irradiation with 10 kGy gamma rays, and no stratification or precipitation after standing at room temperature for 12 months.

Images