An insulating coolant and immersion cooling liquid

Abstract

The present application relates to the technical field of liquid cooling, in particular to an insulating coolant and immersion cooling liquid, which provides an insulating coolant and a preparation method thereof, and has environmental protection and high performance. Through the adoption of a new technology process and route, the performance bottleneck of the prior art is broken: the combination of low pour point and high flash point is realized to adapt to extreme temperature scenes, and the heat dissipation efficiency and equipment safety are improved through the optimization of thermal conductivity and insulation, so that the core problems such as environmental pollution, poor low-temperature fluidity, flammability, and insufficient chemical stability of traditional cooling liquids are finally solved. By introducing fluorine-containing groups into the [(CF3)2SiO] structural unit molecule, the chemical structure and physical and chemical properties of the liquid are changed, such as reducing the surface energy, improving the hydrophobicity, and enhancing the chemical corrosion resistance, so as to meet the demand as an insulating coolant.

Description

Technical Field

[0001] This invention relates to the field of liquid cooling technology, specifically to an insulating coolant and an immersion coolant. Background Technology

[0002] In today's digital age, especially with the development of AI technology, the scale of data centers is exploding, and the computing power of servers is constantly improving. However, the resulting heat dissipation problem has become increasingly prominent, becoming a key bottleneck restricting the development of data centers.

[0003] Traditional air cooling methods are no longer sufficient to meet the cooling requirements of high-density servers due to their low heat dissipation efficiency. Liquid cooling technology, on the other hand, has become the mainstream choice in the market due to its higher efficiency and lower energy consumption.

[0004] Liquid cooling mainly comes in two types: indirect contact liquid cooling, such as cold plate liquid cooling, and direct contact liquid cooling, such as immersion liquid cooling. However, current mainstream technologies in the immersion coolant field suffer from significant environmental drawbacks and performance bottlenecks. Traditional fluorocarbon-based coolants have poor biodegradability, posing a long-term threat to the ecological environment. While silicone oil-based coolants improve low-temperature performance by adjusting the siloxane chains, their pour point (-50℃ to -20℃) still cannot meet the requirements of ultra-low temperature scenarios, and their low thermal conductivity (0.1-0.2 W / m•K) results in insufficient heat dissipation efficiency. Long-term use also leads to oxidation and the formation of silicone resin deposits that clog equipment.

[0005] Mineral oil-based coolants pose a significant risk of flammability and explosion under high-temperature conditions due to their high pour point (> -10℃) and low flash point (< 180℃). Furthermore, they are difficult to degrade after disposal, and incineration releases toxic polycyclic aromatic hydrocarbons (PAHs). In addition, existing technologies generally struggle to balance high insulation (> 40 kV / mm), low viscosity (< 5 cSt), and high thermal conductivity (> 0.15 W / m•K), resulting in an imbalance between heat dissipation efficiency and equipment compatibility. Summary of the Invention

[0006] The purpose of this invention is to provide an insulating coolant to address the aforementioned problems, and to provide an immersion coolant based on this insulating coolant.

[0007] The technical solution adopted in this invention is as follows: a method for preparing an insulating coolant, comprising the following steps:

[0008] S1. The raw materials are pretreated to obtain a mixture of polydimethylsiloxane and fluorine-nitrogen gas;

[0009] S2. The reaction proceeds by adding heated polydimethylsiloxane to the reaction vessel and introducing a fluorine-nitrogen mixture to carry out a fluorination reaction, yielding a mixture containing [(CF3)2SiO] structural units. The chemical equation for the reaction is:

[0010] [(CH3)2SiO]n + 6nF2 →[(CF3)2SiO]n + 6nHF;

[0011] S3. The reaction is terminated. The flow of the fluorine-nitrogen mixture is stopped by judging the degree of fluorination.

[0012] S4. Post-processing: Remove unreacted gases, separate and purify perfluoropolydimethylsiloxane from the mixture containing [(CF3)2SiO] structural units.

[0013] Furthermore, in step S1, the polydimethylsiloxane is dried to remove moisture and its viscosity is adjusted.

[0014] Furthermore, in step S1, polydimethylsiloxane is placed in a vacuum drying oven for drying, and toluene and / or xylene organic solvents are added for dilution to improve its flowability.

[0015] Furthermore, in step S1, the fluorine-nitrogen mixed gas contains 5%-15% fluorine, and is obtained through the following steps:

[0016] A1. Fluorine gas is produced by electrolysis of HF. Potassium hydrofluoride and hydrogen fluoride are mixed in a certain proportion and subjected to electrolysis. An oxidation reaction occurs at the anode to produce fluorine gas, and a reduction reaction occurs at the cathode to produce hydrogen gas. The chemical equation for the reaction is:

[0017] 2KHF2→2KF+F2↑+H2↑;

[0018] A2. To purify the fluorine gas, the fluorine gas collected from the anode of the electrolytic cell is cooled to below -70°C, so that the hydrogen fluoride gas in it is liquefied and separated. This step is repeated until the hydrogen fluoride gas content in the fluorine gas drops to below 0.1%.

[0019] Furthermore, in step S2, C2H6SiO is heated to 40℃-80℃.

[0020] Furthermore, in step S3, infrared spectroscopy analysis is used to determine the degree of fluorination. When the characteristic absorption peaks change significantly, the absorption peak representing the CH bond weakens, while the absorption peak representing the CF bond strengthens and tends to stabilize, the degree of fluorination is determined, and the introduction of the fluorine-nitrogen mixture is stopped.

[0021] Furthermore, in step S3, nuclear magnetic resonance is used to observe changes in molecular structure to determine the degree of fluorination. When the peak area of ​​hydrogen atoms decreases and the peak of fluorine atoms appears and stabilizes, the degree of fluorination is determined to be complete, and the introduction of fluorine-nitrogen mixed gas is stopped.

[0022] Furthermore, in step S3, the degree of fluorination is determined by combining contact angle measurement. If the contact angle increases significantly and stabilizes, the degree of fluorination is determined, and the flow of the fluorine-nitrogen mixture is stopped.

[0023] This application also provides an immersion coolant based on the above-mentioned insulating coolant, comprising an insulating coolant containing [(CF3)2SiO] structural units and a functional substrate, wherein the components by weight are insulating coolant: functional substrate = 1:124.

[0024] Furthermore, the functional substrate comprises a chemical formula of C6H 12 For the ester compounds of O2, select one or more of the following: diethyl hexanoate, methyl hexanoate, butyl acetate, and diisopropyl sebacate.

[0025] The beneficial effects of the present invention include at least one of the following;

[0026] 1. An insulating coolant and its preparation method are provided, which are both environmentally friendly and high-performance. By adopting a new technology and process, the performance bottleneck of the existing technology is broken through: the combination of low pour point and high flash point is achieved to adapt to extreme temperature scenarios, and the heat dissipation efficiency and equipment safety are improved by optimizing thermal conductivity and insulation. Ultimately, the core problems of traditional coolants, such as environmental pollution, poor low-temperature fluidity, flammability and explosion and insufficient chemical stability, are solved.

[0027] 2. By introducing fluorine-containing groups into polydimethylsiloxane molecules, the chemical structure and physicochemical properties of the liquid are altered, such as reducing surface energy, increasing hydrophobicity, and enhancing chemical corrosion resistance, thereby meeting the requirements for use as an insulating coolant.

[0028] 3. The submersible coolant made with insulating coolant has an ultra-low pour point and a high flash point, making it compatible with extreme temperature conditions. This avoids equipment failure caused by insufficient low-temperature fluidity and the risk of high-temperature combustion and explosion. At the same time, it meets the requirements of high insulation and low viscosity, is compatible with existing sealed chamber designs, reduces system modification costs, and avoids flow channel blockage caused by silicone oil oxidation and precipitation. Attached Figure Description

[0029] Figure 1 This is a flowchart of a method for preparing an insulating coolant. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0031] Therefore, the following detailed description of embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0032] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0033] like Figure 1 As shown, a method for preparing an insulating coolant is provided, comprising the following steps:

[0034] S1. The raw materials are pretreated to obtain a mixture of polydimethylsiloxane and fluorine-nitrogen gas;

[0035] S2. The reaction proceeds by adding heated polydimethylsiloxane to the reaction vessel and introducing a fluorine-nitrogen mixture to carry out a fluorination reaction, yielding a mixture containing [(CF3)2SiO] structural units. The chemical equation for the reaction is:

[0036] [(CH3)2SiO]n + 6nF2 → [(CF3)2SiO]n + 6n HF;

[0037] S3. The reaction is terminated. The flow of the fluorine-nitrogen mixture is stopped by judging the degree of fluorination.

[0038] S4. Post-processing: Remove unreacted gases, separate and purify perfluoropolydimethylsiloxane from the mixture containing [(CF3)2SiO] structural units.

[0039] The purpose of this design is to provide an insulating coolant and its preparation method that combines environmental friendliness and high performance. By adopting a new technology and process, it breaks through the performance bottlenecks of existing technologies: it achieves a combination of low pour point and high flash point to adapt to extreme temperature scenarios, and improves heat dissipation efficiency and equipment safety by optimizing thermal conductivity and insulation. Ultimately, it solves the core problems of traditional coolants, such as environmental pollution, poor low-temperature fluidity, flammability and explosion, and insufficient chemical stability.

[0040] Meanwhile, in S1, the polydimethylsiloxane is dried to remove moisture and adjust its viscosity. The polydimethylsiloxane is placed in a vacuum drying oven for drying and diluted with toluene and / or xylene organic solvents to improve its flowability.

[0041] In specific application scenarios, first prepare the required C2H6SiO or its polymer polydimethylsiloxane and fluorine-nitrogen mixture, in which the fluorine content is 5%-15%, and the fluorine is used at a low concentration to control the reaction rate and improve safety.

[0042] In this embodiment, the weight ratio of polydimethylsiloxane and the fluorine-nitrogen mixture is 1%-5%. The reaction vessel is made of a special corrosion-resistant and pressure-resistant material, such as a stainless steel or polytetrafluoroethylene reactor, and is equipped with temperature and pressure monitoring devices. A rigorous airtightness check is performed on the reaction apparatus to ensure no leaks. The polydimethylsiloxane is pretreated, such as by filtering to remove impurities. A suitable solvent is selected based on the viscosity of the polydimethylsiloxane for dilution to further improve its flowability. If its viscosity is high, organic solvents such as toluene or xylene can be used for dilution to facilitate subsequent reactions. Simultaneously, it can also be dried, for example in a vacuum drying oven, to remove any moisture it may contain, preventing moisture from affecting the fluorination reaction and ensuring the smooth progress of the reaction.

[0043] In S2, polydimethylsiloxane is heated to 40℃-80℃. Since the viscosity of polydimethylsiloxane changes with temperature, heating it to around 40℃-80℃ generally gives it good fluidity. However, the specific temperature needs to be determined based on its initial viscosity and the specific requirements of the reaction. If the initial viscosity is high, it may need to be close to 80℃; if the viscosity is low, 40℃-60℃ may be sufficient to achieve better fluidity.

[0044] Diluted polydimethylsiloxane liquid was then added to the reaction vessel, and a fluorine-nitrogen mixture was introduced into the vessel. Initially, the gas introduction rate was controlled to avoid an overly vigorous reaction. Simultaneously, pressure and temperature changes within the reaction vessel were monitored to ensure the reaction proceeded under safe conditions.

[0045] Next, during the introduction of the fluorine-nitrogen mixture, the C2H6SiO units in polydimethylsiloxane undergo a fluorination reaction with the fluorine gas. The reaction generates heat, requiring appropriate cooling devices such as jacketed cooling to control the reaction temperature and maintain it within a set range. The reaction time depends on the desired degree of fluorination and the reaction conditions, generally ranging from one hour to several hours.

[0046] It should be noted that fluorine gas in the fluorine-nitrogen mixture is a highly reactive gas, with fluorine atoms exhibiting extremely high electronegativity and reactivity. When fluorine gas comes into contact with C2H6SiO molecules, it undergoes a substitution reaction with the hydrogen atoms in the C2H6SiO molecules, replacing the hydrogen atoms with fluorine atoms. This introduces fluorine-containing groups into the C2H6SiO molecules, altering the liquid's chemical structure and physicochemical properties, such as reducing surface energy, increasing hydrophobicity, and enhancing chemical corrosion resistance.

[0047] Then, by judging the degree of fluorination, the flow of the fluorine-nitrogen mixture is stopped; that is, when the expected degree of fluorination or reaction time is reached, the flow of the fluorine-nitrogen mixture is stopped. The composition and properties of the reaction products can be analyzed to determine whether the reaction has achieved the expected results.

[0048] Expected determination method: Through infrared spectroscopy analysis, if the characteristic absorption peaks change significantly, such as the absorption peak representing the CH bond weakening while the absorption peak representing the CF bond strengthens and tends to stabilize, it indicates that the fluorination reaction has reached a certain extent.

[0049] Nuclear magnetic resonance (NMR) can also be used to observe changes in molecular structure. If the peak area of ​​hydrogen atoms decreases and the peak of fluorine atoms appears and remains stable, it indicates the extent of the reaction.

[0050] Contact angle measurements can also be used. If the contact angle increases significantly and remains stable, it indicates that the surface hydrophobicity is enhanced, achieving the expected change in physical properties. To significantly improve hydrophobicity, only a portion of hydrogen atoms need to be replaced by fluorine atoms to achieve a contact angle of a certain angle, such as above 120°. To enhance chemical corrosion resistance, a higher degree of fluorination may be required, resulting in the replacement of more hydrogen atoms. The specific degree needs to be determined through continuous optimization of the reaction.

[0051] Finally, the unreacted gas is removed from the obtained C2F6SiO mixture, and C2F6SiO is separated and purified. Specifically, this can be achieved as follows: the crude product mixture obtained after the fluorination reaction is purified to obtain high-purity perfluorohexamethyldisiloxane (C2F6SiO). The specific steps are as follows:

[0052] Acidic gas removal and preliminary purification:

[0053] First, transfer the reaction mixture to a vacuum distillation apparatus;

[0054] Then, a "deacidification" process is carried out: under conditions of 20-30°C and high vacuum, continuous evacuation is performed to completely remove most of the hydrogen fluoride (HF) generated in the reaction and the unreacted fluorine-nitrogen mixture. At the same time, high-purity nitrogen can be introduced for purging to help remove the residual acidic gases.

[0055] Solvent extraction and purification:

[0056] First, mix the deacidified crude product with an equal volume of ultrapure water in a corrosion-resistant separatory funnel, gently shake, and let stand to separate the liquid. This step can effectively dissolve and remove residual water-soluble impurities, such as trace amounts of HF and F⁻ ions.

[0057] Repeat the washing process until the aqueous phase is neutral (pH≈7).

[0058] Deep drying and distillation:

[0059] First, the washed organic phase (C2F6SiO) is transferred to a container containing 3A molecular sieve and allowed to stand and dry to remove trace amounts of moisture.

[0060] Finally, vacuum distillation is carried out under an inert atmosphere.

[0061] By controlling temperature and pressure, the main fraction at a specific boiling range can be collected. For example, at a pressure of -0.1 MPa, the fraction at 75-80°C can be collected to obtain the target product with high purity.

[0062] In the process of removing unreacted gases, separating and purifying C2F6SiO mixtures, the C2F6SiO mixture can be separated into primary distillation, main distillation and rectification at different temperature ranges to remove unreacted HF and H2O, and high-boiling-point fluorosilicone polymers.

[0063] At the same time, it is used in conjunction with a solvent extraction unit to remove polar impurities such as residual HF and F⁻ ions.

[0064] The performance of the insulating coolant was evaluated from two dimensions: high insulation and low viscosity. In this embodiment, the coolant provided in this application was compared with the physicochemical characteristics of three existing comparative samples: Zhejiang Noah 3000A, American 3M FC40, and general-purpose fluorinated liquid. The results are shown in the table below:

[0065] Test Project This embodiment Zhejiang Noah 3000A 3M FC40 (USA) General Fluorinated Liquid Test standards / methods Appearance Transparent and odorless Transparent and odorless Transparent and odorless transparent Visual inspection / smell Fluid properties - Incompressible, in opposite directions Incompressible, in any direction - - Breakdown voltage (kV) 23.45 (2.5mm) 74.2 (Test distance 3mm) 46 (Test distance unknown) 30.61 (Test distance unknown) GB / T 507-2002 Resistivity (ohm•cm) <![CDATA[5.287×10⁻ 8 ]]> - <![CDATA[4.0×10¹ 5 ]]> <![CDATA[8.989×10⁻ 9 ]]> ASTM D257 Dielectric constant 1.8071 2.07 1.9 1.9868 ASTM D924 Reflectivity TD20 1.48 - 1.29 1.2945 - Pour point (°C) < -85.3 -109.67 -57 -122.8 ASTM D97 Open flash point (°C) 144 (No data) None (No flash point, flame retardant) No flash fire was observed when the sample boiled at 114℃. GB / T 267 Density (kg / m³) 882 1815 1855 1781 ASTM D4052 Heat conduction method Pump-driven / ruptureable container Natural convection / airtight container Thermally conductive drive / breakable container - - Surface tension (mN / m, 25℃) 29.14 - 16 15.35 ASTM D1331 Coefficient of thermal expansion (volume / °C) <![CDATA[4572.8×10⁻ 6 (25-140℃)]]> - 0.0012 <![CDATA[7267.33×10⁻ 6 (25-90℃)]]> ASTM D696 Vapor pressure 25℃ No data was measured at 250℃. 2.426 PA 287PA -(No data) ASTM D5191 Kinematic viscosity (cSt, 40℃) 10.42 1.353 2.2 1.17 ASTM D445 Boiling point (°C) > 250 110-115 165 -(No data) ASTM D1120 Decomposition temperature (°C) -(No data) 550 -(No data) -(No data) - Thermal conductivity (W / m·K, 25℃) 0.131 -(No data) 0.065 0.0924 ASTM D7896 Evaporation rate -(No data) 1068 μg / min -(No data) -(No data) ASTM D972 Molar mass (g / mol) 276 -(No data) 650 282 - Specific heat (J / kg·℃, 25℃) 1749 -(No data) 1100 1018 ASTM D2766 Latent heat of vaporization (J / g) 53.013 -(No data) 69 10.809 - Global warming potential 3 120 175 -(No data) - Water solubility (g / 100g water) 0 0 (No data) -(No data) ASTM D4056 Material compatibility guarantee yes yes yes -(No data) - Product warranty (Years) 10 -(No data) 10 -(No data) - Shelf life (Years) -(No data) -(No data) -(No data) -(No data) -

[0066] Through the above comparison, the coolant provided in this embodiment has a low molecular weight (276 g / mol), which is significantly lower than that of 3MFC40 (650 g / mol) in the United States. Its molecular structure is more compact and the intermolecular forces are smaller. This directly contributes to its excellent fluidity and higher diffusion coefficient, which is beneficial for achieving efficient heat exchange in microchannels.

[0067] At the same time, it has a low density (882 kg / m³), which is much lower than all the other three comparative examples (all >1700 kg / m³) and significantly lower than water (1000 kg / m³). This characteristic has significant safety value in the event of a system leak: the coolant will float on top of the aqueous phase, making it easy to separate and recover, greatly simplifying the accident handling process and reducing maintenance costs and environmental risks.

[0068] Furthermore, its ultra-low pour point (< -85.3℃) ensures fluidity in extremely cold environments, superior to 3M FC40 (-57℃).

[0069] Its high boiling point (>250℃) far exceeds that of Zhejiang Noah 3000A (110-115℃) and American 3M FC40 (165℃), thus avoiding high-temperature boiling failure.

[0070] The suitable open flash point (144°C) provides reliable safety redundancy.

[0071] Furthermore, its thermal conductivity (0.131 W / m•K) is superior to that of 3M FC40 (0.065) and general-purpose fluorinated liquid (0.0924).

[0072] With a suitable kinematic viscosity (10.42 cSt) and a high specific heat capacity (1749 J / kg•℃), a good balance is achieved between fluidity and heat storage capacity.

[0073] Regarding high insulation, the high electronegativity of fluorine atoms in C2F6SiO significantly reduces molecular polarity, making it almost non-conductive in the liquid state. Its dielectric strength can reach over 40 kV / mm, which can withstand extreme voltage fluctuations caused by instantaneous overclocking of AI chips. The chemical inertness of the fluorocarbon chain makes it difficult to decompose during long-term use, avoiding the degradation of insulation performance due to ionization or corrosion. It is suitable for direct immersion of high-density electronic components. At the same time, it has been verified that it can remain stable at an insulation resistance of 10^15 Ω·cm, meeting the insulation requirements of a single cabinet with a power of 100kW in a data center.

[0074] Regarding its low viscosity characteristics, the molecular structure of C2F6SiO is optimized through fluorine atom substitution and siloxane skeleton, which significantly reduces internal friction. Compared with existing insulating coolants, C2F6SiO has a shorter molecular chain and a higher degree of fluorine substitution, and its theoretical viscosity can be reduced to 0.2-0.3 cP, which is close to the fluidity of water. The low viscosity reduces pump power consumption and enhances the natural convection capacity of the liquid, thereby improving heat transfer efficiency. Furthermore, the siloxane group has low interfacial tension with metals (copper, aluminum) and plastics (PEEK, PTFE), avoiding microchannel blockage or coating swelling caused by adhesion.

[0075] Meanwhile, in this embodiment, the fluorine gas in the fluorine-nitrogen mixed gas is obtained through the following steps:

[0076] A1. Fluorine gas is produced by electrolysis of HF. Potassium hydrofluoride and hydrogen fluoride are mixed in a certain proportion and subjected to electrolysis. An oxidation reaction occurs at the anode to produce fluorine gas, and a reduction reaction occurs at the cathode to produce hydrogen gas. The chemical equation for the reaction is:

[0077] 2KHF2→2KF+F2↑+H2↑;

[0078] A2. To purify the fluorine gas, the fluorine gas collected from the anode of the electrolytic cell is cooled to below -70°C, so that the hydrogen fluoride gas in it is liquefied and separated. This step is repeated until the hydrogen fluoride gas content in the fluorine gas drops to below 0.1%.

[0079] In specific implementation scenarios, the electrolytic cell is made of special alloy steel or high-performance Monel alloy, paired with a graphite anode and a specially designed cathode. During electrolysis, fluorine gas is produced at the anode and hydrogen gas is released at the cathode. The electrolyte temperature is precisely controlled between 65℃ and 95℃ through an intelligent temperature control system, and the heat generated by electrolysis is removed in a timely manner using high-efficiency heat exchange components to ensure a stable and efficient electrolysis process.

[0080] The fluorine gas produced by electrolysis contains impurities such as hydrogen fluoride, requiring deep purification. First, ultra-low temperature freezing technology is used to cool the fluorine gas to below -70°C, causing most of the hydrogen fluoride gas to liquefy and separate. Utilizing the different low-temperature phase transition points of fluorine and hydrogen fluoride, the cooling tower is frozen to separate the residual hydrogen fluoride from the fluorine gas, thereby improving the purity of the fluorine. The separated gaseous hydrogen fluoride is injected into water to form hydrofluoric acid liquid. Then, calcium hydroxide (solid) is placed in this liquid, allowing them to react to produce calcium fluoride and water. This ensures that the emissions do not pollute the environment. This reaction is repeated for continuous purification. The reaction principle is as follows: Hydrogen fluoride and calcium hydroxide undergo a neutralization reaction to produce calcium fluoride and water. The chemical equation for the reaction is:

[0081] 2HF + Ca(OH)2 = CaF2↓+ 2H2O;

[0082] In this embodiment, based on the above-mentioned insulating coolant, an immersion coolant is provided, comprising an insulating coolant containing [(CF3)2SiO] structural units and a functional substrate, wherein the components by weight are insulating coolant: functional substrate = 1: 124.

[0083] Furthermore, the functional substrate comprises a chemical formula of C6H 12 For the ester compounds of O2, select one or more of the following: diethyl hexanoate, methyl hexanoate, butyl acetate, and diisopropyl sebacate.

[0084] The purpose of this design is that the immersion coolant made with the insulating coolant provided in this embodiment has high thermal conductivity during use, which can directly contact the heat-generating components, significantly improving heat dissipation efficiency, reducing the PUE value of the data center to below 1.1, saving more than 50% energy compared to traditional air-cooling systems, and avoiding the environmental problems of traditional technologies through a new technical route.

[0085] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing an insulating coolant, characterized in that, Includes the following steps: S1. The raw materials are pretreated to obtain a mixture of polydimethylsiloxane and fluorine-nitrogen gas, wherein the pretreatment involves drying the polydimethylsiloxane to remove moisture and adjusting its viscosity; S2. The reaction proceeds by adding heated polydimethylsiloxane to the reaction vessel and introducing a fluorine-nitrogen mixture to carry out a fluorination reaction, yielding a mixture containing [(CF3)2SiO] structural units. The chemical equation for the reaction is: [(CH3)2SiO]n + 6nF2 → [(CF3)2SiO]n + 6nHF; S3. The reaction is terminated. The flow of the fluorine-nitrogen mixed gas is stopped by judging the degree of fluorination. S4. Post-processing: Removing unreacted gases, separating and purifying perfluoropolydimethylsiloxane from the mixture containing [(CF3)2SiO] structural units, including acid gas removal and preliminary purification. First, transfer the mixture to a vacuum distillation apparatus; Then, a deacidification process is carried out: under conditions of 20-30°C and high vacuum, the gas is continuously pumped out to remove most of the hydrogen fluoride HF generated in the reaction and the unreacted fluorine-nitrogen mixed gas. At the same time, high-purity nitrogen is introduced for purging to help remove the residual acidic gas. Solvent extraction and purification: First, the deacidified crude product is mixed with an equal volume of ultrapure water in a corrosion-resistant separatory funnel, gently shaken, and allowed to stand before separation to remove residual water-soluble impurities. Repeat the water washing process until the aqueous phase is neutral; Deep drying and distillation: First, transfer the washed organic phase to a container containing 3A molecular sieves and let it stand to dry in order to remove trace amounts of moisture. Finally, vacuum distillation was carried out under an inert atmosphere. By controlling the temperature and pressure, the fraction at 75°C-80°C was collected under a pressure of -0.1MPa to obtain the target product with high purity.

2. The method for preparing an insulating coolant according to claim 1, characterized in that, In step S1, polydimethylsiloxane is placed in a vacuum drying oven for drying, and toluene and / or xylene organic solvents are added for dilution to improve its flowability.

3. The method for preparing an insulating coolant according to claim 1, characterized in that, In step S1, the fluorine-nitrogen mixed gas contains 5%-15% fluorine, which is obtained through the following steps: A1. Fluorine gas is produced by electrolysis of HF. Potassium hydrofluoride and hydrogen fluoride are mixed in a certain proportion and subjected to electrolysis. An oxidation reaction occurs at the anode to produce fluorine gas, and a reduction reaction occurs at the cathode to produce hydrogen gas. The chemical equation for the reaction is: 2KHF2→2KF+F2↑+H2↑; A2. To purify the fluorine gas, the fluorine gas collected from the anode of the electrolytic cell is cooled to below -70°C, so that the hydrogen fluoride gas in it is liquefied and separated. This step is repeated until the hydrogen fluoride gas content in the fluorine gas drops to below 0.1%.

4. The method for preparing an insulating coolant according to claim 1, characterized in that, In step S2, polydimethylsiloxane is heated to 40°C-80°C.

5. The method for preparing an insulating coolant according to claim 1, characterized in that, In step S3, infrared spectroscopy is used to determine the degree of fluorination. When the characteristic absorption peaks change significantly, the absorption peak representing the CH bond weakens, while the absorption peak representing the CF bond strengthens and tends to stabilize, the degree of fluorination is determined to be complete, and the introduction of the fluorine-nitrogen mixed gas is stopped.

6. The method for preparing an insulating coolant according to claim 1, characterized in that, In step S3, nuclear magnetic resonance is used to observe changes in molecular structure to determine the degree of fluorination. When the peak area of ​​hydrogen atoms decreases and the peak of fluorine atoms appears and stabilizes, the degree of fluorination is determined to be complete, and the introduction of fluorine-nitrogen mixed gas is stopped.

7. The method for preparing an insulating coolant according to claim 1, characterized in that, In step S3, the degree of fluorination is determined by combining contact angle measurement. If the contact angle increases significantly and stabilizes, the degree of fluorination is determined and the flow of fluorine-nitrogen mixed gas is stopped.

8. An immersion coolant, characterized in that, The product comprises the insulating coolant as described in any one of claims 1 to 7 and a functional substrate, wherein the components are in the following proportions by weight: insulating coolant: functional substrate = 1: 124.

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