Organic silicon cooling liquid for immersed liquid cooling as well as preparation method and application of organic silicon cooling liquid

Abstract

The invention discloses an organic silicon cooling liquid for immersed liquid cooling and a preparation method and application thereof.The organic silicon cooling liquid is prepared from raw materials including 1, 1, 3, 3-tetramethyldisiloxane, long-chain alpha olefin, a phenyl siloxane ring body, a methyl siloxane ring body and the like through hydrosilylation and ring-opening chain extension polymerization reaction under the action of a catalyst to precisely regulate and control a molecular structure, and the organic silicon cooling liquid is prepared. And the long-chain alkyl-terminated polysiloxane with phenyl on the side chain is prepared. The prepared polysiloxane product has the advantages of being low in viscosity, high in flash point, low in pour point, high in heat conductivity coefficient and the like when being used as cooling liquid, and compared with fluorine-containing series cooling liquid which is used at present, the cost is reduced by 80% or above, so that the polysiloxane product has wide prospects in immersed cooling application in the fields of data centers, charging piles, new energy batteries and the like.

Description

Technical Field

[0001] This invention relates to the field of coolant technology, and more specifically, to an organosilicon coolant for immersion liquid cooling, its preparation method, and its application. Background Technology

[0002] Currently, with the rapid development of artificial intelligence, cloud computing, and high-performance computing technologies, the computing power demand of data centers is exploding, and chip power density continues to rise (e.g., the power of a single GPU chip has exceeded 700W). Traditional air cooling technology can no longer meet the heat dissipation requirements. Liquid cooling technology, especially immersion liquid cooling, is becoming a key solution for high-density computing facilities due to its high heat dissipation efficiency and significant energy-saving advantages (power consumption can be reduced by 30%-50% compared to air cooling systems). However, immersion coolants still face several technical bottlenecks.

[0003] For example, synthetic oils suffer from a surge in kinematic viscosity and a low flash point at low temperatures, which is detrimental to the long-term stable and safe operation of equipment. Fluorinated fluids, on the other hand, have high density, complex production processes, and high costs; some types may also pose a potential risk to the ozone layer or health hazards. Furthermore, common immersion coolants have high dielectric constants, which can easily lead to signal attenuation in high-frequency signal transmission, affecting the signal integrity of high-performance chips such as GPUs and TPUs. Material compatibility also presents challenges; different base oils exhibit significant differences in compatibility with specific non-metallic materials (such as EPDM and VMQ seals), easily causing problems such as swelling or additive precipitation, thereby affecting the overall reliability of the system.

[0004] Compared to fluorinated fluids and synthetic oils, silicone coolants exhibit significant advantages: stable kinematic viscosity, high flash point (typically >150℃), good thermal stability, better material compatibility, and are safer and more environmentally friendly. Their low density (generally below 0.90 g / cm³) effectively reduces data center load and pumping energy consumption. The industry has stringent requirements for the key performance indicators of immersion silicone coolants, typically requiring: kinematic viscosity <20 cst at 25℃, flash point >150℃, dielectric constant ≤2.5, and high dielectric strength and good material compatibility.

[0005] Despite the numerous advantages of silicone coolants, existing products still face challenges in balancing performance and cost. On the one hand, some products require the introduction of large amounts of low molecular weight components to achieve low viscosity, which often leads to a decrease in flash point or thermal stability. On the other hand, some products improve thermal conductivity by increasing the phenyl content, but this may cause excessive dielectric constant or material compatibility issues.

[0006] Furthermore, traditional preparation processes typically employ a two-step method: first, hydroxyl-terminated polysiloxanes are synthesized, followed by chain extension via silanol condensation. This route often uses alkaline catalysts (such as tetramethylammonium hydroxide), and under strongly alkaline conditions, the molecular weight distribution of the silanol condensation reaction is difficult to precisely control, thus affecting the overall performance of the coolant in terms of viscosity, thermal stability, and other aspects.

[0007] Therefore, it is necessary to provide an organosilicon coolant with low viscosity, high flash point, and good thermal stability. Summary of the Invention

[0008] To address the problems existing in the prior art, the first objective of this invention is to provide an organosilicon coolant for immersion liquid cooling and its preparation method. The coolant prepared by this method has the characteristics of low viscosity, high flash point, good low-temperature resistance, low dielectric constant, and high thermal conductivity, meeting the application requirements of multiple fields and having broad application prospects. The second objective of this invention is to provide an application of the organosilicon coolant for immersion liquid cooling.

[0009] To solve the above problems, the present invention adopts the following technical solution.

[0010] An organosilicon coolant for immersion liquid cooling, characterized in that it comprises compounds with the following general chemical formula: Formula 1: RSi(CH3)2-[Si(C6H5) c (CH3) （2-c） -O] a - [Si(CH3)2-O] b -Si(CH3)2R; Wherein, R is selected from C 4-16 The alkyl group, where a is 0-8, b is 2-20, and c is 1 or 2; the values ​​of R, a, and b satisfy the molecular weight of Formula 1 in the range of 300-2000.

[0011] This invention also provides a method for preparing the above-mentioned immersion liquid cooling silicone coolant, comprising the following steps: S1: Mix α-olefin with catalyst 1 evenly, and slowly add 1,1,3,3-tetramethyldisiloxane dropwise. After reacting for a certain time, filter and remove the low-carbon residue to obtain long-chain alkyl-terminated tetramethyldisiloxane. S2: Long-chain alkyl-terminated tetramethyldisiloxane, phenylsiloxane cyclic and methylsiloxane cyclic are mixed evenly, catalyst 2 is added, and after reacting for a certain time, the mixture is filtered and degraded to obtain organosilicon coolant.

[0012] Furthermore, in step S1, the α-olefin is one or a mixture of two or more olefins with a carbon chain length of 4-16. More preferably, it is an olefin with a carbon chain length of 6, 8, or 10.

[0013] Furthermore, in step S1, the molar ratio of the α-olefin and 1,1,3,3-tetramethyldisiloxane is 2-2.4:1, preferably 2-2.05:1.

[0014] Furthermore, in step S1, the catalyst 1 is one or a combination of two of the Karstedt catalyst and the Speier catalyst; the amount of catalyst 1 is 0.5-10 ppm of the total mass of α-olefin and 1,1,3,3-tetramethyldisiloxane; preferably 1-5 ppm.

[0015] Furthermore, in step S2, the phenylsiloxane cyclic compound includes one or more combinations of octaphenylcyclotetrasiloxane, tetraphenylcyclotetrasiloxane, and diphenylcyclotetrasiloxane.

[0016] Furthermore, in step S2, the methylsiloxane cyclic compound includes one or more combinations of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, and decamethylcyclopentasiloxane.

[0017] Furthermore, in step S2, the catalyst 2 is at least one of concentrated sulfuric acid, trifluoromethanesulfonic acid, acidic resin, and acidic clay. The amount of catalyst 2 is 0.01-8% of the total mass of long-chain alkyl-terminated tetramethyldisiloxane, phenylsiloxane cyclic and methylsiloxane cyclic. When the selected catalyst is concentrated sulfuric acid, acidic resin or acidic clay, the catalyst amount is preferably 3-6%. When the selected catalyst is trifluoromethanesulfonic acid, the catalyst amount is preferably 0.5-3‰.

[0018] Furthermore, in step S2, the molar ratio of the long-chain alkyl-terminated tetramethyldisiloxane, phenylsiloxane cyclic and methylsiloxane cyclic is 1:0.25-4:0.25-5.

[0019] Furthermore, in step S1, the reaction temperature is 40-90℃ and the reaction time is 1-5h; in step S2, the reaction temperature is 40-100℃ and the reaction time is 2-8h.

[0020] The present invention also provides the application of the above-described immersion liquid cooling organosilicon coolant in immersion liquid cooling of data centers or new energy vehicle batteries.

[0021] Compared with the prior art, the advantages of this invention are: I. The preparation method provided in this scheme can not only fully promote the reaction, effectively reduce the generation of hydrogen bond residues, improve the power generation efficiency and reduce the dielectric constant, but also precisely control the molecular structure, thereby improving the thermal conductivity and low temperature resistance of the structure.

[0022] Second, the organosilicon coolant product provided by this invention has passed the liquid cooling application performance test, and the relevant indicators far exceed the application requirements, showing broad application prospects. Detailed Implementation

[0023] Example 1: C8H 17 Si(CH3)2-Si(C6H5)(CH3)-O- [Si(CH3)2-O]4-Si(CH3)2C8H 17 Preparation Step 1: Add 0.7 mg (based on platinum content) of Speier catalyst to 224 g of octene, mix thoroughly, and slowly add 134 g of 1,1,3,3-tetramethyldisiloxane dropwise, controlling the temperature to not exceed 80 °C. After the addition is complete, maintain the reaction at 80 °C for 5 hours. Remove low-boiling-point substances by vacuum distillation to obtain octyldisiloxane.

[0024] Step 2: Add 266g of octamethylcyclotetrasiloxane, 122g of tetraphenylcyclotetrasiloxane, and 28g of concentrated sulfuric acid to 320g of octyldisiloxane obtained in Step 1, and stir the mixture at 80℃ for 8 hours. After the reaction is complete, add excess sodium carbonate to neutralize the sulfuric acid, filter, and distill under reduced pressure to obtain 603g of product, with a conversion rate of 85%.

[0025] Example 2:

[0026] This embodiment differs from Example 1 only in that the amount of Speier catalyst added in the first step is adjusted to 0.9 mg. 621 g of product was obtained, with a conversion rate of 88%.

[0027] Example 3:

[0028] This embodiment differs from Example 1 only in that the amount of Speier catalyst added in the first step is adjusted to 3.58 mg. 638 g of product was obtained, with a conversion rate of 90%.

[0029] Example 4:

[0030] This embodiment differs from Example 1 only in that the amount of Speier catalyst added in the first step is adjusted to 0.358 mg. 560 g of product was obtained, with a conversion rate of 79%.

[0031] Example 5:

[0032] This embodiment differs from Example 1 only in that the amount of Speier catalyst added in the first step is adjusted to 1.79 mg. 631 g of product was obtained, with a conversion rate of 89%.

[0033] As shown in Examples 1-5, when other conditions remain constant, changing the amount of catalyst 1 results in the following: when the amount of catalyst 1 is less than 1 ppm of the total mass of α-olefin and 1,1,3,3-tetramethyldisiloxane, the reaction conversion rate decreases instead of increasing; while when the amount of catalyst 1 exceeds 5 ppm of the total mass, the conversion rate does not significantly improve. Therefore, the preferred amount of catalyst 1 is 1-5 ppm of the total mass of α-olefin and 1,1,3,3-tetramethyldisiloxane.

[0034] Example 6:

[0035] The difference between this embodiment and Example 1 is that the Speier catalyst in the first step was replaced with a Karstedt catalyst, and the amount added was 0.7 mg. 581 g of product was obtained, with a conversion rate of 82%.

[0036] Example 7:

[0037] The difference between this embodiment and Example 1 is that the catalyst, concentrated sulfuric acid, in the second step was replaced with trifluoromethanesulfonic acid, and the amount added was 0.75g. 612g of product was obtained, with a conversion rate of 86%.

[0038] Example 8:

[0039] The difference between this embodiment and Example 1 is that the concentrated sulfuric acid catalyst in the second step was replaced with acidic clay, and the amount added was 28g. 610g of product was obtained, with a conversion rate of 86%.

[0040] Example 9: C8H 17 Si(CH3)2-[Si(C6H5)(CH3)-O]2- [Si(CH3)2-O]4-Si(CH3)2C8H 17 Preparation The method and preparation steps are the same as in Example 1. The difference between this example and Example 1 is that the amount of tetraphenylcyclotetrasiloxane added is adjusted to 244g, and the amount of concentrated sulfuric acid added is adjusted to 33g accordingly. 697g of product was obtained, with a conversion rate of 84%.

[0041] Example 10: C8H 17 Si(CH3)2-[Si(C6H5)2-O]2- [Si(CH3)2-O]4-Si(CH3)2C8H 17 Preparation The method and preparation steps are the same as in Example 1. The difference between this example and Example 1 is that tetraphenylcyclotetrasiloxane is replaced with octaphenylcyclotetrasiloxane, and the amount added is 177g. The amount of concentrated sulfuric acid added is adjusted accordingly to 30.5g. 641g of product was obtained, with a conversion rate of 84%.

[0042] Example 11: C8H 17Si(CH3)2-Si(C6H5)(CH3)-O- [Si(CH3)2-O]8-Si(CH3)2C8H 17 Preparation The method and preparation steps are the same as in Example 1. The difference between this example and Example 1 is that the amount of octamethylcyclotetrasiloxane added is adjusted to 592g, and the amount of concentrated sulfuric acid is adjusted accordingly to 42g. 879g of product was obtained, with a conversion rate of 85%.

[0043] Example 12: C 10 H 21 Si(CH3)2-Si(C6H5)(CH3)-O- [Si(CH3)2-O]4-Si(CH3)2C 10 H 21 Preparation Add 0.83 mg (based on platinum content) of Karstedt catalyst to 280 g of decene, mix thoroughly, and slowly add 134 g of 1,1,3,3-tetramethyldisiloxane dropwise while controlling the temperature to not exceed 80 °C. After the addition is complete, maintain the reaction at 80 °C for 5 h. Remove low-boiling-point substances by vacuum distillation to obtain decyldisiloxane.

[0044] 264 g of octamethylcyclotetrasiloxane, 121 g of tetraphenylcyclotetrasiloxane, and 30 g of concentrated sulfuric acid were added to 370 g of the prepared decyldisiloxane, and the mixture was stirred at 80 °C for 8 h. After the reaction was complete, excess sodium carbonate was added to neutralize the sulfuric acid, and the mixture was filtered and distilled under reduced pressure to obtain the product. 650 g of product was obtained, with a conversion rate of 86%.

[0045] Example 13: C 12 H 25 Si(CH3)2-Si(C6H5)(CH3)-O- [Si(CH3)2-O]4-Si(CH3)2C 12 H 25 Preparation Add 0.94 mg (based on platinum content) of Karstedt catalyst to 336 g of dodecene, mix thoroughly, and slowly add 134 g of 1,1,3,3-tetramethyldisiloxane dropwise while controlling the temperature to not exceed 80 °C. After the addition is complete, maintain the reaction at 80 °C for 5 h. Remove low-boiling-point substances by vacuum distillation to obtain dodecyldisiloxane.

[0046] 420g of the prepared dodecyldisiloxane was mixed with 264g of octamethylcyclotetrasiloxane, 121g of tetraphenylcyclotetrasiloxane, and 32g of concentrated sulfuric acid. The mixture was stirred at 80°C for 8 hours. After the reaction was complete, excess sodium carbonate was added to neutralize the sulfuric acid. The mixture was filtered and distilled under reduced pressure to obtain the product. 698g of product was obtained, with a conversion rate of 87%.

[0047] Comparative Example 1 without Tetraphenylcyclotetrasiloxane: C 12 H 25 Si(CH3)2-[Si(CH3)2-O]4-Si(CH3)2C 12 H 25 Preparation The method and preparation steps are the same as in Example 13. The difference between this example and Example 13 is that tetraphenylcyclotetrasiloxane is not added to the reaction raw materials, and the concentrated sulfuric acid is adjusted to 27g. 508g of product was obtained, with a conversion rate of 87%.

[0048] Comparative Example 2: The dropping rates of 1,1,3,3-tetramethyldisiloxane were varied. The method and steps were the same as in Example 1, but the rate of adding 1,1,3,3-tetramethyldisiloxane was too fast and the temperature was not controlled, causing the temperature to soar to 130°C, the system to boil, and the synthesized octyldisiloxane to be yellowish with a conversion rate of 63%.

[0049] Comparative Example 3 with reduced catalyst 2 dosage: The method and steps are the same as in Example 1, except that the amount of concentrated sulfuric acid catalyst added in the second step is adjusted to 7g. The ring-opening reaction is incomplete, with a conversion rate of 58%.

[0050] Comparative Example 4 without the addition of octamethylcyclotetrasiloxane: C8H 17 Si(CH3)2-Si(C6H5)(CH3)-O-Si(CH3)2C8H 17 Preparation The method and steps were the same as in Example 1, except that octamethylcyclotetrasiloxane was not added to the reaction raw materials, and the concentrated sulfuric acid was adjusted to 17.6 g. 362 g of product was obtained, with a conversion rate of 82%.

[0051] Comparative Example 5 with increased amount of octamethylcyclotetrasiloxane: C8H 17 Si(CH3)2-Si(C6H5)(CH3)-O- [Si(CH3)2-O] 28 -Si(CH3)2C8H 17 Preparation The method and steps are the same as in Example 1, except that the amount of octamethylcyclotetrasiloxane added was adjusted to 1865g, and the amount of concentrated sulfuric acid was adjusted to 92g. The viscosity was too high (36 cst), resulting in excessive energy consumption in practical applications. 1845g of product was obtained, with a conversion rate of 80%.

[0052] Comparative Example 6: Preparation of (CH3)3Si-Si(C6H5)(CH3)-O-[Si(CH3)2-O]6-Si(CH3)3 by replacing octene with hexamethyldisiloxane The method and steps were the same as in Example 1, except that octene was replaced with hexamethyldisiloxane, and the amount added was 162g. The product obtained was methyl-terminated with alkyl groups instead of methyl groups. 503g of product was obtained, with a conversion rate of 78%.

[0053] Experimental Example 1: The coolants involved in Examples 1, 9-13, Comparative Examples 1, and 4-6 were subjected to performance tests according to the group standard "T / SHSIC 0202-2023 Technical Indicators and Test Methods for Single Coolants in Immersion Liquid Cooling Systems for Data Centers". The test results are shown in Table 1.

[0054] ; The data in Table 1 shows that: The silicone coolant product provided by this invention has undergone liquid cooling application performance testing (according to T / SHSIC 0202-2023 standard), and the relevant indicators far exceed the application requirements. In particular, the coolant provided in the examples, with its high thermal conductivity, suitable viscosity, excellent flash point, and high volume resistivity, exhibits significant comprehensive advantages in Comparative Examples 1 and 4-6. Specifically, the shortcomings of each comparative example further highlight the superiority of the examples.

[0055] The lack of a phenyl structure in Comparative Example 1 results in a low thermal conductivity of only 0.1451 W / (mk). At the same time, its viscosity is low (6.2 cst) and its flash point is only 174℃. This means that the coolant in Comparative Example 1 is prone to evaporation at high temperatures and has insufficient heat transfer efficiency, which cannot meet the dual requirements of "high temperature safety" and "efficient heat dissipation" of the liquid cooling system. In practical applications, it may cause safety hazards due to its low flash point or become a heat dissipation bottleneck due to its poor thermal conductivity.

[0056] Comparative Example 4 also has a low viscosity (7.4 cst), but due to the lack of siloxane units in its structure, its pour point is as high as -35°C. This means that it is prone to solidification or a sharp drop in fluidity at low temperatures, making it unsuitable for cold regions or low-temperature start-up scenarios; at the same time, its volume resistivity is only 2.7 × 10⁻⁶. 11 With a leakage current of Ω·m, the insulation performance weakens, which may threaten the safety of electrical equipment due to increased leakage current, and the overall practicality is greatly limited.

[0057] Comparative Example 5 maintained a pour point < -70℃, but had a thermal conductivity of only 0.1396 W / (mk), a high flash point (295℃), a viscosity that increased sharply to 36.6 cst, and a volume resistivity of only 2.6 × 10⁻⁶. 11Ω·m. This means that the high viscosity of the coolant in Comparative Example 5 will cause a surge in the power consumption of the circulating pump (too high energy consumption in actual applications), the low thermal conductivity will weaken the heat dissipation efficiency, and the low volume resistivity will sacrifice the insulation reliability, completely deviating from the core requirements of liquid cooling systems for "low energy consumption", "efficient heat transfer" and "safe insulation".

[0058] Although the viscosity (6.7 cst) and pour point (< -70°C) of Comparative Example 6 are only slightly different from those of the Example, its flash point is only 172°C and its volume resistivity is only 2.1 × 10⁻⁶. 11 The temperature is low (Ω·m), and the structure lacks alkyl links, resulting in a low thermal conductivity. A low flash point means it is easily combustible at high temperatures, while its low volume resistivity indicates severely inadequate insulation, failing to meet the basic requirements of liquid cooling systems for "high-temperature stability" and "electrical safety."

[0059] In summary, Examples 1 and 9-13, through precise control of the phenyl / alkyl group ratio, siloxane chain length, and the synergistic effect of key components, not only avoid the defects of individual indicators in the comparative examples that "seem to meet the standards but are unbalanced overall," but also achieve synergistic optimization of thermal conductivity, viscosity, flash point, and volume resistivity. Their comprehensive performance far exceeds application requirements, fully verifying the outstanding advantages of the organosilicon coolant of this invention in terms of high safety, efficient heat dissipation, wide temperature adaptability, and reliable insulation, and has broad market prospects (especially suitable for cutting-edge fields such as data centers and new energy batteries that are highly sensitive to thermal management and electrical safety).

Claims

1. A silicone coolant for immersion liquid cooling, characterized in that: This includes compounds represented by the following general chemical formulas: Formula 1: RSi(CH3)2-[Si(C6H5) c (CH3) （2-c） -O] a - [Si(CH3)2-O] b -Si(CH3)2R; Wherein, R is selected from C 4-16 The alkyl group, where a is 0-8, b is 2-20, and c is 1 or 2; the values ​​of R, a, and b satisfy the molecular weight of Formula 1 in the range of 300-2000.

2. The method for preparing an organosilicon coolant for immersion liquid cooling according to claim 1, characterized in that: Includes the following steps: S1: Mix α-olefin with catalyst 1 evenly, and slowly add 1,1,3,3-tetramethyldisiloxane dropwise. After reacting for a certain time, filter and remove the low-carbon residue to obtain long-chain alkyl-terminated tetramethyldisiloxane. S2: Long-chain alkyl-terminated tetramethyldisiloxane, phenylsiloxane cyclic and methylsiloxane cyclic are mixed evenly, catalyst 2 is added, and after reacting for a certain time, the mixture is filtered and degraded to obtain organosilicon coolant.

3. The method for preparing an organosilicon coolant for immersion liquid cooling according to claim 2, characterized in that: In step S1, the α-olefin is one or more of two olefins with a carbon chain length of 4-16, and the molar ratio of the α-olefin to 1,1,3,3-tetramethyldisiloxane is 2-2.4:

1.

4. The method for preparing an organosilicon coolant for immersion liquid cooling according to claim 2, characterized in that: In step S1, catalyst 1 is one or a combination of Karstedt catalyst and Speier catalyst; the amount of catalyst 1 is 0.5-10 ppm of the total mass of α-olefin and 1,1,3,3-tetramethyldisiloxane.

5. The method for preparing an organosilicon coolant for immersion liquid cooling according to claim 2, characterized in that: In step S2, the phenylsiloxane cyclic compound includes one or more combinations of octaphenylcyclotetrasiloxane, tetraphenylcyclotetrasiloxane, and diphenylcyclotetrasiloxane.

6. The method for preparing an organosilicon coolant for immersion liquid cooling according to claim 2, characterized in that: In step S2, the methylsiloxane cyclic compound includes one or more combinations of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, and decamethylcyclopentasiloxane.

7. The method for preparing an organosilicon coolant for immersion liquid cooling according to claim 2, characterized in that: In step S2, the catalyst 2 is at least one of concentrated sulfuric acid, trifluoromethanesulfonic acid, acidic resin and acidic clay, and the amount of catalyst 2 is 0.01-8% of the total mass of long-chain alkyl-terminated tetramethyldisiloxane, phenylsiloxane cyclic and methylsiloxane cyclic.

8. The method for preparing an organosilicon coolant for immersion liquid cooling according to claim 2, characterized in that: In step S2, the molar ratio of the long-chain alkyl-terminated tetramethyldisiloxane, phenylsiloxane cyclic and methylsiloxane cyclic is 1:0.25-4:0.25-5.

9. The method for preparing an organosilicon coolant for immersion liquid cooling according to claim 2, characterized in that: In step S1, the reaction temperature is 40-90℃ and the reaction time is 1-5h; in step S2, the reaction temperature is 40-100℃ and the reaction time is 2-8h.

10. The organosilicon coolant for immersion liquid cooling according to claim 1 is used in immersion liquid cooling of data centers or new energy vehicle batteries.