A perfluoropolyether coolant suitable for server thermal management and its application

Abstract

The present invention discloses a perfluoropolyether coolant suitable for server heat management and its application, belonging to the technical field of fluorinated liquid cooling, specifically, an alkoxy cyclotriphosphazene derivative is used as an auxiliary agent, and is mixed and stirred evenly with perfluoropolyether to obtain a perfluoropolyether coolant. The present invention proposes for the first time the application of an alkoxy cyclotriphosphazene derivative in the preparation of a perfluoropolyether coolant suitable for server heat management, and by combining perfluoropolyether with an alkoxy cyclotriphosphazene derivative and utilizing the unique six-membered cyclic N=P conjugated structure in the derivative, the acid regurgitation problem of the cooling medium can be solved efficiently and at low cost, ensuring that the acid value is stable and does not change during long-term operation.

Description

Technical Field

[0001] The present invention discloses a perfluoropolyether coolant suitable for server heat management and its application, and specifically relates to a perfluoropolyether coolant with perfluoropolyether as a main component and an alkoxy cyclotriphosphazene derivative as an auxiliary agent, and the application of the alkoxy cyclotriphosphazene derivative as an auxiliary agent in the preparation of a perfluoropolyether coolant suitable for server heat management, belonging to the technical field of fluorinated liquid cooling. Background Art

[0002] With the rapid development and continuous progress of science and technology, the application of fluorinated liquid cooling in various industries has become a hot topic. Whether it is data centers, power systems, or medical equipment, fluorinated liquid cooling has shown incomparable advantages. Taking data centers as an example, servers need a lot of heat dissipation to ensure operating efficiency. Fluorinated liquid, due to its ultra-high thermal conductivity, can make servers and other equipment reach the ideal operating temperature, and can take heat away from the equipment faster. Therefore, using fluorinated liquid cooling, data centers can accommodate more hardware in a smaller space, and can greatly reduce the energy consumption generated by heat dissipation, effectively reducing operating costs.

[0003] Perfluoropolyether (PFPE) is a perfluoropolymer compound with advantages such as low volatility, oxidation resistance, low surface tension, good diffusivity, and high temperature resistance, which makes perfluoropolyether coolants widely used in immersion cooling technology. This type of coolant has the characteristics of good chemical stability, high temperature stability, low volatility, good electrical insulation, and green environmental protection. However, in order to ensure the continuous and stable operation of cooling equipment, it is necessary to provide a perfluoropolyether coolant that can be used for a long time and has no acid reflux problem.

[0004] In the prior art, the invention patent with publication number CN113621352A provides a perfluoropolyether compound with a specific polymer structure, which has the characteristics of high insulation, low viscosity, high boiling point, high thermal conductivity, non-toxic and non-flammable. By forming a cooling medium with perfluoropolyether diol, it has excellent heat dissipation function when used in the cooling system of electronic equipment. The cooling medium and the fan are used to compare the CPU for continuous operation for 1 month. The cooling effect on the CPU is significantly higher than the conventional fan heat exchange. The CPU temperature can be controlled at 33.2°C during heat exchange, while the CPU temperature is 72.5°C during fan heat exchange. At the same time, the composition of the cooling medium before and after use is basically unchanged, indicating that the cooling medium does not cause swelling corrosion to components such as the CPU and has very good material compatibility. However, in practical applications, since perfluoropolyether diol needs to be prepared by catalytic reduction and is difficult to synthesize, this will lead to a significant increase in material costs and is not conducive to the industrial production of cooling media.

[0005] In addition, the invention patent with the publication number CN113861949A also provides a perfluoropolyether coolant composed of perfluoropolyether, perfluoroamine, fluorine-modified pyridine acrylate, and tetrafluoroethylene oligomer. By adding perfluoroamine and fluorine-modified pyridine acrylate to the perfluoropolyether coolant, the acid value effect of the perfluoropolyether as the main component can be reduced, and at different temperatures, as time goes by, it has a good acid value reduction and system stabilization effect, thereby solving the problem of acidification and instability in long-term use, and improving the control of the perfluoropolyether liquid cooling system over unstable acidity. However, when preparing the perfluoropolyether coolant, perfluoroamine and fluorine-modified pyridine acrylate need to be added in large proportions to achieve the effect of stabilizing the acid value, and there is also the problem of high material cost. Summary of the invention

[0006] In order to overcome the problem of greatly increased material costs when solving the acid value stability and acid regurgitation phenomenon of perfluoropolyether coolant, the present invention proposes for the first time the use of alkoxy cyclotriphosphazene derivatives in the preparation of perfluoropolyether coolant suitable for server thermal management. By combining perfluoropolyether with alkoxy cyclotriphosphazene derivatives and utilizing the unique six-membered cyclic N=P conjugated structure in the derivatives, the acid regurgitation problem of the cooling medium can be solved efficiently and at low cost, ensuring that the acid value is stable and does not change during long-term operation. At the same time, the present invention also provides a perfluoropolyether coolant suitable for server thermal management containing the derivative.

[0007] The present invention is achieved through the following technical scheme: the use of alkoxy cyclotriphosphazene derivatives in the preparation of perfluoropolyether coolants suitable for server heat management, the alkoxy cyclotriphosphazene derivatives are used as auxiliary agents, and the perfluoropolyether is mixed and stirred evenly to obtain the perfluoropolyether coolant.

[0008] The structure of the alkoxy cyclotriphosphazene derivative is shown in the following formula (1):

[0009] (1)

[0010] In formula (1), R and R" are each selected from -CH3, -CH2CH3, and -CH2CF3.

[0011] The alkoxy cyclotriphosphazene derivative is a composite composition of two or three different structures in formula (1).

[0012] According to weight percentage, 5 to 10 parts of alkoxy cyclotriphosphazene derivative and 90 to 95 parts of perfluoropolyether are mixed and stirred uniformly.

[0013] The structure of the perfluoropolyether is shown in the following formula (2):

[0014] Rf1-(C3F6O) m-(CF2O) q -Rf2 (2)

[0015] In formula (2), Rf 1、 Rf2 is selected from any one of -OCF3, -OCF2CF3, -OCF2CF2CF3 or -OCF(CF3)2; m and q represent the number of repeating units, wherein 2≤m≤10, 0≤q / m≤1.

[0016] The preparation steps of the alkoxy cyclotriphosphazene derivative include:

[0017] S1. reacting metallic sodium with anhydrous methanol, ethanol and trifluoroethanol to obtain the corresponding sodium alcoholate intermediate I;

[0018] S2. Two or three of the sodium alcohol intermediates I are added to a non-protonic solvent solution of hexachlorocyclotriphosphazene to react, and then distilled under reduced pressure to obtain an alkoxycyclotriphosphazene derivative.

[0019] In the step S1, metallic sodium is reacted with anhydrous methanol, ethanol and trifluoroethanol respectively at a temperature of -15 to -30°C in a nitrogen atmosphere.

[0020] In the step S1, the molar ratio of metallic sodium to alcohol is 1.05 to 1.1.

[0021] In the step S2, the molar ratio of the added sodium alcoholate intermediate I to the hexachlorocyclotriphosphazene is 6.05-6.1:1.

[0022] In the step S2, the reaction temperature is 90-120° C. and the reaction time is 8-12 hours.

[0023] In the step S2, the aprotic solvent is selected from at least one of dioxane, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether.

[0024] A perfluoropolyether coolant suitable for server thermal management as mentioned above has the following performance index system:

[0025] Boiling point: 160~270℃;

[0026] Acid value: <0.03 mg / g;

[0027] Specific gravity: 1.75~1.90;

[0028] Kinematic viscosity @25℃: 1.8~10cst;

[0029] Saturated vapor pressure @25℃: <200Pa;

[0030] Dielectric constant @25℃: 1KHz: <2.1;

[0031] Breakdown voltage @2.54cm: >30KV;

[0032] Thermal conductivity: >0.07W / m.℃;

[0033] Specific heat capacity: >0.23 Cal / (g.℃).

[0034] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0035] (1) The present invention uses an alkoxy cyclotriphosphazene derivative as an auxiliary agent, which can provide a highly efficient acid reflux inhibition effect in a perfluoropolyether coolant. At the same time, it can reduce the production cost of the coolant, thereby meeting the large-scale application and deployment of cooling media in server thermal management.

[0036] (2) The alkoxy cyclotriphosphazene derivatives of the present invention are easy to synthesize and prepare, and can achieve a highly efficient inhibition effect with a relatively low addition amount in the perfluoropolymer coolant, which can bring a higher cost advantage to the production of cooling media.

[0037] (3) The alkoxy cyclotriphosphazene derivatives of the present invention have a six-membered cyclic N=P conjugated structure and are electron-deficient structures. When used in combination with perfluoropolyether, they can combine with free radicals to inhibit molecular chain scission of perfluoropolyether. Therefore, they can provide a highly efficient acid reflux inhibition effect for the cooling medium, ensuring that the acid value is stable and does not change. DETAILED DESCRIPTION

[0038] The invention objectives, technical solutions and beneficial effects of the present invention are further described in detail below.

[0039] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the claimed invention, and unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs.

[0040] It is known that the acid regurgitation problem of perfluoropolyether coolant (cooling medium) is caused by the presence of trace amounts of unsaturated or unstable impurities in perfluoropolyether, and these unsaturated or unstable impurities will cause free radicals to cause continuous chain scission during the long-term operation of the cooling medium, increasing its acid value and dielectric constant, thereby corroding metal materials and parts, which is not conducive to its long-term effective operation in server thermal management. Although the existing patents CN113621352A and CN113861949A provide that adding perfluoropolyether diol, or perfluoroamine and fluorine-modified pyridine acrylate to perfluoropolyether can suppress the unstable acidity of the cooling medium to a certain extent, these additives are difficult to prepare and have a large addition ratio, which increases the material cost of cooling medium production on the other hand, and does not promote and apply them on an industrial scale.

[0041] In order to solve the above technical problems, the present invention proposes for the first time to use an alkoxy cyclotriphosphazene derivative as an auxiliary agent mixed with perfluoropolyether to prepare a cooling medium, and the cooling medium has the following technical advantages:

[0042] (1) Alkoxy cyclotriphosphazene derivatives are electron-deficient structures with a six-membered cyclic N=P conjugated structure, which can inhibit the chain breakage of perfluoropolyether molecules and ensure the stability of the acid value of the cooling medium during long-term operation.

[0043] (2) Alkoxy cyclotriphosphazene derivatives can provide highly effective acid reflux inhibition effects and only need to be added in small amounts to perfluoropolyether. By reducing the amount of additives added, the preparation difficulty and cost advantages of the cooling medium can be improved to a certain extent.

[0044] (3) The preparation process of alkoxy cyclotriphosphazene derivatives is simple, the synthesis process is easy, and the yield is high, which can effectively control the material cost in the production of cooling media.

[0045] The present invention is further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

[0046] Example 1: Preparation of alkoxycyclotriphosphazene derivatives

[0047] 760g of metallic sodium and 3000g of trifluoroethanol were added to a reactor, nitrogen was passed into the reactor, and the temperature of the reactor was controlled to -15°C in an inert nitrogen atmosphere. The reaction produced sodium trifluoroethanol for standby use; 387g of metallic sodium and 513g of anhydrous methanol were added to the reactor, and in the same manner, the temperature of the reactor was controlled to -15°C in an inert nitrogen atmosphere. The reaction produced sodium methoxide for standby use; 290g of metallic sodium and 671g of anhydrous ethanol were added to the reactor, and in the same manner, the temperature of the reactor was controlled to -15°C in an inert nitrogen atmosphere. The reaction produced sodium ethoxide for standby use.

[0048] 696 g of hexachlorocyclotriphosphazene was dissolved in dioxane to prepare an aprotic solvent solution of hexachlorocyclotriphosphazene with a mass concentration of 20%, which was added to a reaction container. Then, a ternary composition of sodium trifluoroethoxide, sodium methoxide and sodium ethoxide (the molar ratio of sodium trifluoroethoxide: sodium methoxide: sodium ethoxide was 3.05:2:1) was added to the reaction container. The molar ratio of sodium ethoxide to hexachlorocyclotriphosphazene in the reaction container was controlled to be 6.05:1. Then, the reaction was carried out at a temperature of 100° C. for 10 hours. Sodium chloride was separated by filtration. The reaction product was then introduced into a distiller. After dioxane was removed by reduced pressure distillation, 970 g of a liquid product, an alkoxycyclotriphosphazene derivative, was obtained with a yield of 96%.

[0049] The structure of the alkoxy cyclotriphosphazene derivative is as follows:

[0050] N3P3(CF3CH2O) 3.05 (CH3O)2(CH3CH2O)1 (3)

[0051] Example 2: Preparation of alkoxycyclotriphosphazene derivatives

[0052] Sodium trifluoroethoxide and sodium methoxide were prepared in the same manner as in Example 1 and set aside.

[0053] 1045g of hexachlorocyclotriphosphazene was dissolved in ethylene glycol dimethyl ether to prepare a non-protonic solvent solution of hexachlorocyclotriphosphazene with a mass concentration of 10%, and the solution was added to a reaction container. Then, a binary composition of sodium trifluoroethoxide and sodium methoxide (the molar ratio of sodium trifluoroethoxide: sodium methoxide is 2.3:1) was added to the reaction container, and the molar ratio of sodium methoxide to hexachlorocyclotriphosphazene in the reaction container was controlled to be 6.1:1. Then, the reaction was carried out at a temperature of 120°C for 8h, and sodium chloride was separated by filtration. The reaction product was then introduced into a distiller, and the ethylene glycol dimethyl ether was removed by reduced pressure distillation to obtain 1940g of a liquid product alkoxycyclotriphosphazene derivative with a yield of 97%.

[0054] The structure of the alkoxy cyclotriphosphazene derivative is as follows:

[0055] N3P3(CF3CH2O) 4.6 (CH3O)2 (4)

[0056] Example 3: Preparation of alkoxycyclotriphosphazene derivatives

[0057] Sodium trifluoroethoxide and sodium ethoxide were prepared in the same manner as in Example 1 and set aside.

[0058] 1045 g of hexachlorocyclotriphosphazene was dissolved in dioxane and diethylene glycol dimethyl ether to prepare a non-protonic solvent solution of hexachlorocyclotriphosphazene with a mass concentration of 15%, and the solution was added to a reaction container. Then, a binary composition of sodium trifluoroethoxide and sodium ethoxide (the molar ratio of sodium trifluoroethoxide:sodium ethoxide is 2.3:1) was added to the reaction container, and the molar ratio of sodium ethoxide to hexachlorocyclotriphosphazene in the reaction container was controlled to be 6.06:1. Then, the reaction was carried out at a temperature of 90°C for 12 hours, and sodium chloride was separated by filtration. The reaction product was then introduced into a distiller, and dioxane and diethylene glycol dimethyl ether were removed by reduced pressure distillation to obtain 2036 g of a liquid product alkoxycyclotriphosphazene derivative, with a yield of 95%.

[0059] The structure of the alkoxy cyclotriphosphazene derivative is as follows:

[0060] N3P3(CF3CH2O) 4.6 (CH3CH2O)2 (5)

[0061] Example 4: Preparation of perfluoropolyether coolant

[0062] The perfluoropolyether used in this embodiment is CF3(C3F6O)5(CF2O) 0.2 CF3, from Chengdu Chenguang Boda New Materials Co., Ltd.; alkoxy cyclotriphosphazene derivative from Example 1.

[0063] 4500 g of perfluoropolyether and 500 g of alkoxycyclotriphosphazene derivative were mixed and stirred uniformly to obtain a perfluoropolyether coolant.

[0064] Example 5: Preparation of perfluoropolyether coolant

[0065] The perfluoropolyether used in this example is the same as that used in Example 4; the alkoxy cyclotriphosphazene derivative is from Example 2.

[0066] 9000 g of perfluoropolyether and 1000 g of alkoxycyclotriphosphazene derivative were mixed and stirred uniformly to obtain a perfluoropolyether coolant.

[0067] Example 6: Preparation of perfluoropolyether coolant

[0068] The perfluoropolyether used in this example is the same as that used in Example 4; the alkoxy cyclotriphosphazene derivative is from Example 3.

[0069] 9500 g of perfluoropolyether and 500 g of alkoxycyclotriphosphazene derivative were mixed and stirred uniformly to obtain a perfluoropolyether coolant.

[0070] Comparative Example 1:

[0071] This comparative example is a perfluoropolyether coolant prepared by mixing the perfluoropolyether in Example 4 with a perfluoropolyether diol in a mass ratio of 9:1 and stirring them uniformly.

[0072] Comparative Example 2:

[0073] The perfluoropolyether coolant used is produced by Solvay, and its product number is HT170.

[0074] The perfluoropolyether coolants of the above embodiments and comparative examples were subjected to the following tests:

[0075] 1. Basic performance test

[0076] Boiling Point: Use ASTM D1120 Standard Test Method for Boiling Point of Engine Coolants.

[0077] Acid value: adopt "NB / SH / T 0434-2013 No. 4839 Chemical Resistant Lubricating Oil Appendix A Acid Value Determination Method for Fluorinated Oil Products".

[0078] Specific gravity: Adopt the standard test method of GB / T 4472-2011.

[0079] Kinematic viscosity: ASTM D445 standard method for testing kinematic viscosity of transparent / non-transparent liquids is used.

[0080] Saturated vapor pressure: GB / T 8017 "Determination of saturated vapor pressure of petroleum products - Reid method", instrument name: Fully automatic saturated vapor pressure tester (Reid method), instrument model: DSL-8017ZD, applicable standards: GB / T 8017, ASTM D323 test method.

[0081] Dielectric constant: GB / T 1409 is used to measure the dielectric constant and dielectric loss factor of electrical insulating materials at power frequency, audio frequency, and high frequency (including meter wave wavelength).

[0082] Breakdown voltage: GB / T507-2002 "Determination of Breakdown Voltage of Insulating Oil" is adopted.

[0083] Thermal conductivity: Using ASTM D5470 test method.

[0084] Specific heat capacity: The specific heat capacity determination method of NB / SH / T 0632-2014 is adopted.

[0085] Referring to the above detection method, the perfluoropolyether coolants of Examples 4 to 6, and Comparative Examples 1 and 2 were tested, and the test results are shown in Table 1 below.

[0086] Table 1

[0087]

[0088] As can be seen from Table 1 above, the perfluoropolyether coolant prepared by adding an alkoxy cyclotriphosphazene derivative in the present invention has basic performance equivalent to that of the existing perfluoropolyether coolant added with perfluoropolyether diol and the commercially available perfluoropolyether coolant produced by Solvay, and both are suitable for cooling media for heat management of servers.

[0089] (II) Continuous operation test

[0090] A temperature-accelerated aging immersion experiment was conducted. The test method is as follows: simulate the extreme temperature conditions of server failure, and immerse the metal / non-metal, rubber, and plastic materials involved in the server system in perfluoropolyether coolant at 85°C for 500 hours. The acid value, viscosity, dielectric properties and other indicators of the coolant were tested before and after the experiment, and the compatibility level was evaluated.

[0091] The grade evaluation criteria are shown in Table 2 below.

[0092] Table 2

[0093]

[0094] The perfluoropolyether coolants of Example 5, Example 6 and Comparative Example 1 were tested respectively. The test results are shown in Tables 3 to 5 below.

[0095] Table 3 Test results of perfluoropolyether coolant of Example 5

[0096]

[0097] Table 4 Test results of perfluoropolyether coolant of Example 6

[0098]

[0099] Table 5 Test results of perfluoropolyether coolant of Comparative Example 1

[0100]

[0101] Based on Tables 3 to 5 above, it can be seen that the perfluoropolyether coolants provided in Example 5, Example 6 and Comparative Example 1 have been subjected to a 500-hour high-temperature accelerated immersion test under the extreme temperature conditions of the coolant simulating the server. The test results show that they have very stable material compatibility with representative metals, plastics, rubbers, etc. in the server, and can ensure its continuous operation during the server thermal management process. However, since the perfluoropolydiol used in Comparative Example 1 still has the problems of high synthesis difficulty and high preparation cost, the perfluoropolyether coolant of the present invention is preferred in the thermal management process of servers, data centers, etc., which can reduce production costs and meet large-scale industrial applications and deployments.

[0102] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. Application of alkoxy cyclotriphosphazene derivatives in the preparation of perfluoropolyether coolants suitable for server thermal management, characterized in that: The alkoxy cyclotriphosphazene derivative is used as an auxiliary agent, mixed with the perfluoropolyether and stirred evenly to obtain the perfluoropolyether coolant. The structure of the alkoxy cyclotriphosphazene derivative is shown in the following formula (1): （1） In formula (1), R and R" are each selected from -CH3, -CH2CH3, and -CH2CF3. The alkoxy cyclotriphosphazene derivative is a composite composition of two or three different structures in formula (1).

2. The use according to claim 1, characterized in that: According to weight percentage, 5 to 10 parts of alkoxy cyclotriphosphazene derivative and 90 to 95 parts of perfluoropolyether are mixed and stirred uniformly.

3. The use according to claim 1, characterized in that: The structure of the perfluoropolyether is shown in the following formula (2): Rf1-(C3F6O) m -(CF2O) q -Rf2 (2) In formula (2), Rf 1、 Rf2 is selected from any one of -OCF3, -OCF2CF3, -OCF2CF2CF3 or -OCF(CF3)2; m and q represent the number of repeating units, wherein 2≤m≤10, 0≤q / m≤1.

4. The use according to claim 1, characterized in that: The preparation steps of the alkoxy cyclotriphosphazene derivative include: S1. reacting metallic sodium with anhydrous methanol, ethanol and trifluoroethanol to obtain the corresponding sodium alcoholate intermediate I; S2. Two or three of the sodium alcohol intermediates I are added to a non-protonic solvent solution of hexachlorocyclotriphosphazene to react, and then distilled under reduced pressure to obtain an alkoxycyclotriphosphazene derivative.

5. The use according to claim 4, characterized in that: In the step S1, metallic sodium is reacted with anhydrous methanol, ethanol and trifluoroethanol respectively at a temperature of -15 to -30°C in a nitrogen atmosphere.

6. The use according to claim 4, characterized in that: In the step S1, the molar ratio of metallic sodium to alcohol is 1.05 to 1.

1.

7. The use according to claim 4, characterized in that: In the step S2, the molar ratio of the added sodium alcoholate intermediate I to the hexachlorocyclotriphosphazene is 6.05-6.1:

1.

8. The use according to claim 4, characterized in that: In the step S2, the reaction temperature is 90-120° C. and the reaction time is 8-12 hours.

9. The use according to claim 4, characterized in that: In the step S2, the aprotic solvent is selected from at least one of dioxane, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether.

10. A perfluoropolyether coolant suitable for server thermal management according to any one of claims 1 to 9, characterized in that: Its performance index system is as follows: Boiling point: 160~270℃; Acid value: <0.03 mg / g; Specific gravity: 1.75~1.90; Kinematic viscosity @25℃: 1.8~10cst; Saturated vapor pressure @25℃: <200Pa; Dielectric constant @25℃: 1KHz: <2.1; Breakdown voltage @2.54cm: >30KV; Thermal conductivity: >0.07W / m.℃; Specific heat capacity: >0.23 Cal / (g.℃).

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