Cooling liquid composition for immersed cooling of data center
By using benzotriazole imidazoline compounds and silane coupling agents to modify aluminum nitride nanoparticles in data center immersion coolants, the problems of inorganic nanoparticle agglomeration and the lack of synergy in corrosion inhibitor performance are solved, improving the thermal conductivity and metal protection of the coolant, and ensuring the long-term stability and efficient heat dissipation of the system.
Patent Information
- Application Number
- CN202610284260.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-10
- Publication Date
- 2026-04-28
AI Technical Summary
In existing data center immersion cooling systems, inorganic nanoparticles tend to agglomerate and settle, leading to a decrease in thermal conductivity. Furthermore, the combination of corrosion inhibitors and dispersants presents a problem of synergistic effects, impacting the overall performance and reliability of the coolant.
A corrosion inhibitor and dispersant obtained by grafting benzotriazole imidazoline compound with polyisobutylene, combined with aluminum nitride nanoparticles modified by silane coupling agent, forms a stable dispersion layer, prevents nanoparticle aggregation and forms a protective film on the metal surface, thereby improving dispersion stability and corrosion inhibition performance.
It achieves efficient dispersion of inorganic thermally conductive fillers and corrosion protection against various metals, improves the thermal conductivity and reliability of coolant, and meets the high power density heat dissipation requirements of data centers.
Smart Images
Figure CN121930797A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of cooling media, specifically a coolant composition for immersion cooling of data centers. Background Technology
[0002] With the rapid development of cloud computing, artificial intelligence, and high-performance computing, the power density of data center servers continues to rise, resulting in increasingly concentrated heat. Traditional air-cooling methods are gradually approaching their heat dissipation limits. Immersion liquid cooling technology directly immerses heat-generating electronic components in insulating coolant, achieving efficient heat exchange through direct liquid contact. It offers significant advantages such as high heat dissipation efficiency, low noise, and small space occupation, and has become one of the key directions for solving the heat dissipation problem of high-power chips.
[0003] In immersion liquid cooling systems, the performance of the coolant directly determines the system's heat dissipation efficiency, reliability, and total cost of ownership. An ideal coolant needs to possess high insulation, high thermal conductivity, corrosion resistance, and long-term chemical and physical stability. Among these, hydrocarbon oils such as mineral oils and synthetic hydrocarbons are widely researched and used due to their relatively low cost and good insulation properties. To further improve the thermal conductivity of the base oil, technicians often add inorganic nanoparticles with high thermal conductivity.
[0004] However, this technological approach faces two key challenges: First, due to their high surface energy, inorganic nanoparticles are prone to agglomeration and sedimentation in non-polar oil media, leading to damage to the heat conduction network and decreased heat dissipation performance. Although modifying the particle surface with silane coupling agents can improve dispersibility to some extent, long-term stability and resistance to sedimentation under complex thermal environments still need to be strengthened. Second, the coolant needs to be in long-term contact with various metal materials (such as copper, aluminum, and solder) within the server, necessitating the addition of effective corrosion inhibitors to prevent electrochemical corrosion.
[0005] However, this simple compounding model of "corrosion inhibitor + dispersant" has inherent defects: First, multiple additive molecules may compete for adsorption or interact in the oil phase, affecting the full realization of their respective effects. Second, the dispersion and stabilization effect on inorganic particles and the corrosion inhibition and protection effect on metal surfaces are not synergistic, and there is room for optimization of the overall formulation efficiency.
[0006] Therefore, developing a novel coolant additive that can simultaneously and efficiently solve the dispersion stability problem of inorganic thermally conductive fillers and the corrosion protection problem of various metals, achieving "multiple effects with one additive," simplifying the formulation, and improving the overall performance and reliability of the coolant has become an important technical requirement in this field. Summary of the Invention
[0007] Purpose of the invention: In view of the above-mentioned technical problems, the present invention proposes a coolant composition for immersion cooling of data centers.
[0008] The technical solution adopted is as follows: A coolant composition for immersion cooling of data centers, comprising: Base oil, inorganic thermally conductive particles, and corrosion inhibitors and dispersants; The corrosion inhibitor and dispersant is obtained by grafting a benzotriazole imidazoline compound with polyisobutylene.
[0009] Furthermore, the structural formula of the benzotriazolylimidazoline compound is shown below: ; Where R is an alkenyl group.
[0010] Furthermore, the alkenyl group has ≥10 carbon atoms.
[0011] Furthermore, the mass ratio of the base oil, inorganic thermally conductive particles, and corrosion inhibitor / dispersant is 85-95:1-2:0.1-0.5.
[0012] Furthermore, the base oil includes at least one of hydrocarbon mineral oil, silicone oil, synthetic ester oil, and natural ester oil.
[0013] Furthermore, the inorganic thermally conductive particles are aluminum nitride nanoparticles.
[0014] Furthermore, the aluminum nitride nanoparticles are modified with a silane coupling agent.
[0015] Furthermore, the silane coupling agent is at least one of KH-550, KH-560, or KH-570.
[0016] Furthermore, the preparation method of the corrosion inhibitor / dispersant is as follows: The free radical polymerization can be carried out by adding benzotriazolylimidazoline compound, polyisobutylene and free radical initiator to an organic solvent.
[0017] Furthermore, the coolant composition also includes an antioxidant.
[0018] The beneficial effects of this invention are: This invention provides a coolant composition for immersion cooling in data centers. The nano-size effect of aluminum nitride nanoparticles significantly increases their contact area with the base oil, thereby enhancing heat transfer at the interface, shortening the heat conduction path from the heat source to the coolant, and significantly improving the thermal conductivity of the coolant. However, due to their high specific surface area and strong surface energy, they are prone to agglomeration and sedimentation in the base oil, leading to a decrease in thermal conductivity. After modification, a silane coupling agent is coated on the surface of the aluminum nitride nanoparticles. Through steric hindrance and electrostatic repulsion, the nanoparticles are prevented from agglomerating close to each other, ensuring their uniform dispersion in the base oil.
[0019] In this invention, the corrosion inhibitor and dispersant is obtained by grafting a benzotriazole imidazoline compound with polyisobutylene. Both the benzotriazole group and the imidazoline group in its structure can form stable complexes with metal ions. These complexes will be deposited on the metal surface as a dense molecular film, which physically blocks the contact between the corrosive medium and the metal, inhibits the oxidation and dissolution of the metal, and improves the corrosion inhibition performance.
[0020] As the core unit of physical adsorption film formation, polyisobutylene long chain can not only ensure that the corrosion inhibitor is uniformly dispersed in the oil phase, but also form an adsorption film layer on the metal surface through van der Waals forces. This adsorption film layer can effectively block the migration of corrosive media to the metal surface and reduce electrochemical corrosion. Furthermore, the polyisobutylene long chain and the silane coupling agent on the surface of aluminum nitride nanoparticles can achieve stable bonding through hydrogen bonding and hydrophobic interactions. This prevents the aluminum nitride nanoparticles from settling and agglomerating, while forming a "nanoparticle-corrosion inhibitor" composite protective layer on the metal surface. This stabilizes the dispersion state of the aluminum nitride nanoparticles, allowing them to remain stably dispersed in the coolant for a long time and maintain the continuous function of the heat dissipation network. This not only meets the high-efficiency heat dissipation requirements of high-power-density scenarios such as immersion cooling in data centers, but also ensures the reliability of the system through long-term stability. The addition of the corrosion inhibitor and dispersant also effectively solves the dispersion stability problem of inorganic thermally conductive fillers and the corrosion protection problem of various metals, achieving "multiple effects with one agent," simplifying the formulation, and improving the overall performance and reliability of the coolant. The coolant composition of this invention has excellent thermal conductivity and good corrosion inhibition properties for metals, which can meet the needs of immersion cooling in data centers. Attached Figure Description
[0021] Figure 1 This is a synthetic route diagram of the benzotriazolylimidazoline compound prepared in Example 1. Detailed Implementation
[0022] Unless otherwise specified in the examples, the conditions were performed under standard conditions or as recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products. Techniques not mentioned in this invention refer to existing technologies. Unless otherwise specified, the following examples and comparative examples are parallel experiments, using the same processing steps and parameters. Example
[0023] A coolant composition for immersion cooling of data centers, comprising, by weight: 80 parts of No. 25 mineral oil, 1.5 parts of KH-560 modified aluminum nitride nanoparticles, 0.25 parts of corrosion inhibitor and dispersant, and 0.2% of antioxidant BHT; The preparation method of the above corrosion inhibitor / dispersant is as follows: Under nitrogen protection, 50 mmol of 14-pentadecanoic acid, 50 mmol of β-hydroxyethyl ethylenediamine, and 5.6 g of calcium oxide were added to a flask equipped with a water separator, condenser, and thermometer. The mixture was heated to 60 °C with a magnetic stirrer to carry out the acylation and dehydration reaction. After reacting at a constant temperature for 4 h, the temperature was increased to 140 °C to continue the cyclization reaction for 5 h. After cooling, the reaction solution was filtered, and 500 ml of deionized water and 500 ml of dichloromethane were added to the filtrate. The mixture was transferred to a separatory funnel, and the organic layer solution was separated by standing. After drying with anhydrous sodium sulfate, the solution was subjected to rotary evaporation under reduced pressure. The product was collected and recrystallized with acetone, followed by vacuum drying to obtain the intermediate with a yield of 72.3% and an HPLC purity of 99.3%.
[0024] 40 g of benzotriazole, 150 mL of deionized water, and 16 g of sodium hydroxide were added to a three-necked flask. Then, 36 g of aqueous chloroacetic acid solution was added dropwise over 30 min. The mixture was stirred at 90 °C for 3 h. After cooling to room temperature, hydrochloric acid was added dropwise until a large amount of white precipitate appeared. The precipitate was filtered, washed three times with deionized water, and dried under vacuum to obtain 2-(1-benzotriazole)acetic acid. 3.54 g of 2-(1-benzotriazole)acetic acid was weighed and placed in a dry three-necked flask. 20 mL of dry benzene was added, and 5 mL of thionyl chloride was slowly added dropwise under ice-water bath cooling, controlling the addition temperature to ≤5 °C. After reacting for 0.5 h, the reaction was continued at 60-65 °C for 5 h. After cooling to room temperature, the solvent and remaining thionyl chloride were evaporated under reduced pressure. The product was cooled and dried under vacuum to obtain 2-(1-benzotriazole)acetyl chloride, with a yield of 50.8%.
[0025] The intermediate (molar ratio 1:1) and 2-(1-benzotriazolyl)acetyl chloride were placed in a dried three-necked flask, and an appropriate amount of dry pyridine was added. The mixture was heated to reflux and reacted for 2.5 h. After cooling, an appropriate amount of water and sodium bicarbonate were added, and the solvent and water were evaporated under reduced pressure. An appropriate amount of ethanol was added to the residue, and the mixture was refluxed and stirred for 20 min. After hot filtration, the filtrate was collected and rotary evaporated until a solid precipitated. The precipitate was filtered off, recrystallized with anhydrous ethanol, filtered, and dried under vacuum to obtain the benzotriazolylimidazoline compound. The synthetic route is shown in [reference needed]. Figure 1 Theoretical value: 481.68, measured value: 482.20 [M+H] + The HPLC purity was 99.1%, and the yield was 58.3%.
[0026] Polyisobutylene (PIB-1 000) was added to a flask equipped with a thermometer, reflux condenser, and stirrer. After dissolving it in xylene, initiator AIBN was added, and stirring was continued for 30 minutes. Then, benzotriazole imidazoline compound was dissolved in xylene and slowly added dropwise to the reaction system. The mass ratio of polyisobutylene, benzotriazole imidazoline compound, and initiator AIBN was 10:1:0.01. The mixture was then heated to reflux and stirred for 8 hours. After the reaction was completed, the material was cooled to room temperature and precipitated in acetone. The mixture was then filtered, the product was collected, and dried to obtain the corrosion inhibitor dispersant.
[0027] The preparation method of KH-560 modified aluminum nitride nanoparticles is as follows: Weigh aluminum nitride nanoparticles and silane coupling agent KH-560 in a mass ratio of 1:1 into a beaker, add enough acetone solution as a solvent, then place the prepared solution on a magnetic stirrer and heat to reflux. After stirring for 2 hours, centrifuge, collect the solid and dry it.
[0028] The preparation method of the above coolant composition: Add corrosion inhibitor and antioxidant BHT to No. 25 mineral oil and stir at 100 rpm for 10 min. Then add KH-560 modified aluminum nitride nanoparticles and stir and disperse at 800 rpm for 30 min. Example
[0029] A coolant composition for immersion cooling of data centers, comprising, by weight: 95 parts of No. 25 mineral oil, 2 parts of KH-560 modified aluminum nitride nanoparticles, 0.5 parts of corrosion inhibitor and dispersant, and 0.5% of antioxidant BHT; The preparation methods of the above corrosion inhibitor and dispersant and KH-560 modified aluminum nitride nanoparticles are the same as in Example 1.
[0030] The preparation method of the above coolant composition: Add corrosion inhibitor and antioxidant BHT to No. 25 mineral oil and stir at 100 rpm for 10 min. Then add KH-560 modified aluminum nitride nanoparticles and stir and disperse at 800 rpm for 30 min. Example
[0031] A coolant composition for immersion cooling of data centers, comprising, by weight: 85 parts of No. 25 mineral oil, 1 part of KH-560 modified aluminum nitride nanoparticles, 0.1 parts of corrosion inhibitor and dispersant, and 0.1% of antioxidant BHT; The preparation methods of the above corrosion inhibitor and dispersant and KH-560 modified aluminum nitride nanoparticles are the same as in Example 1.
[0032] The preparation method of the above coolant composition: Add corrosion inhibitor and antioxidant BHT to No. 25 mineral oil and stir at 100 rpm for 10 min. Then add KH-560 modified aluminum nitride nanoparticles and stir and disperse at 800 rpm for 30 min. Example
[0033] A coolant composition for immersion cooling of data centers, comprising, by weight: 95 parts of No. 25 mineral oil, 1 part of KH-560 modified aluminum nitride nanoparticles, 0.5 parts of corrosion inhibitor and dispersant, and 0.1% of antioxidant BHT; The preparation methods of the above corrosion inhibitor and dispersant and KH-560 modified aluminum nitride nanoparticles are the same as in Example 1.
[0034] The preparation method of the above coolant composition: Add corrosion inhibitor and antioxidant BHT to No. 25 mineral oil and stir at 100 rpm for 10 min. Then add KH-560 modified aluminum nitride nanoparticles and stir and disperse at 800 rpm for 30 min. Example
[0035] A coolant composition for immersion cooling of data centers, comprising, by weight: 85 parts of No. 25 mineral oil, 2 parts of KH-560 modified aluminum nitride nanoparticles, 0.1 parts of corrosion inhibitor and dispersant, and 0.5% of antioxidant BHT; The preparation methods of the above corrosion inhibitor and dispersant and KH-560 modified aluminum nitride nanoparticles are the same as in Example 1.
[0036] The preparation method of the above coolant composition: Add corrosion inhibitor and antioxidant BHT to No. 25 mineral oil and stir at 100 rpm for 10 min. Then add KH-560 modified aluminum nitride nanoparticles and stir and disperse at 800 rpm for 30 min. Example
[0037] The method is basically the same as in Example 1, except that aluminum nitride nanoparticles are used instead of KH-560 modified aluminum nitride nanoparticles, that is, the aluminum nitride nanoparticles are not modified by the silane coupling agent KH-560.
[0038] It is basically the same as Example 1, except that KH-560 modified aluminum nitride nanoparticles are not added.
[0039] It is basically the same as Example 1, except that no corrosion inhibitor or dispersant is added.
[0040] The method is basically the same as in Example 1, except that a benzotriazole imidazoline compound is used instead of a corrosion inhibitor / dispersant. The preparation method of the benzotriazole imidazoline compound is the same as in Example 1.
[0041] The coolant compositions from Examples 1-6 and Comparative Examples 1-3 were used as samples for performance testing.
[0042] Test method for thermal conductivity: ASTM D7896-2019 "Temporary hot wire liquid thermal conductivity method for determination of thermal conductivity, thermal diffusivity and volumetric heat capacity of engine coolant and related fluids".
[0043] The polarization resistance of different samples at room temperature was tested using an electrochemical testing instrument. A traditional three-electrode system was employed, consisting of a working electrode, an auxiliary electrode, and a reference electrode. The working electrode was selected from brass, cast iron, and cast aluminum, respectively. The reference electrode was a saturated calomel electrode, and the auxiliary electrode was a platinum electrode. The higher the polarization resistance value, the better the corrosion resistance of the sample, thus evaluating the corrosion inhibition performance of the sample. First, an open-circuit potential monitoring was performed for 3600 s to ensure that the system reached a steady state. Subsequently, the polarization resistance was measured, with an applied potential range of ±10 mV, a scan rate of 0.125 mV / s, and a testing time of 7 days.
[0044] Thermal conductivity (W / m·K at 40℃) <![CDATA[Polarization resistance / (brass, kΩ / cm 2 )]]> <![CDATA[Polarization resistance / (cast iron, kΩ / cm 2 )]]> <![CDATA[Polarization resistance / (cast aluminum, kΩ / cm 2 )]]> Example 1 0.155 327 88 172 Example 2 0.148 324 80 166 Example 3 0.152 318 83 168 Example 4 0.145 312 79 163 Example 5 0.151 316 82 167 Example 6 0.142 301 74 160 Comparative Example 1 0.129 274 65 151 Comparative Example 2 0.140 216 34 119 Comparative Example 3 0.141 295 72 158 As shown in Table 1 above, the coolant composition of the present invention has excellent thermal conductivity and good corrosion inhibition properties for metals, which can meet the needs of immersion cooling in data centers.
[0045] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A coolant composition for immersion cooling of data centers, characterized in that, include: Base oil, inorganic thermally conductive particles, and corrosion inhibitors and dispersants; The corrosion inhibitor and dispersant is obtained by grafting a benzotriazole imidazoline compound with polyisobutylene.
2. The coolant composition according to claim 1, characterized in that, The structural formula of the benzotriazolylimidazoline compound is shown below: ； Where R is an alkenyl group.
3. The coolant composition according to claim 2, characterized in that, The alkenyl group has ≥10 carbon atoms.
4. The coolant composition according to claim 1, characterized in that, The mass ratio of the base oil, inorganic thermally conductive particles, and corrosion inhibitor / dispersant is 85-95:1-2:0.1-0.
5.
5. The coolant composition according to claim 1, characterized in that, The base oil includes at least one of hydrocarbon mineral oil, silicone oil, synthetic ester oil, and natural ester oil.
6. The coolant composition according to claim 1, characterized in that, The inorganic thermally conductive particles are aluminum nitride nanoparticles.
7. The coolant composition according to claim 6, characterized in that, The aluminum nitride nanoparticles were modified with a silane coupling agent.
8. The coolant composition according to claim 7, characterized in that, The silane coupling agent is at least one of KH-550, KH-560 or KH-570.
9. The coolant composition according to claim 1, characterized in that, The preparation method of the corrosion inhibitor / dispersant is as follows: The free radical polymerization can be carried out by adding benzotriazolylimidazoline compound, polyisobutylene and free radical initiator to an organic solvent.
10. The coolant composition according to any one of claims 1-9, characterized in that, It also includes antioxidants.