Fluoroether-modified siloxane, and preparation method and application thereof

Abstract

The application discloses fluorine ether modified siloxane and a preparation method and application thereof. The process route takes high hydrogen-containing silicone oil as a synthetic raw material, and finally obtains high-purity fluorine ether modified siloxane through steps of silicon hydrogen addition reaction with fluorine-containing olefins, distillation purification and the like, and a structural formula is as follows: wherein m is an integer selected from 1-200, n is an integer selected from 1-250, and x is an integer selected from 1-200; Q is -CH3 or -CF3, R0 represents a straight-chain alkyl group, and R represents a perfluoropolyether group. ƒ The synthetic product has good dielectric properties, a thermal conductivity coefficient and other related parameters, and can be well applied to the field of digital liquid cooling heat dissipation.

Description

Technical Field

[0001] This invention belongs to the field of organosilicon oil compounds and their synthesis, and designs a fluoroether-modified siloxane, its preparation method and application. Background Technology

[0002] With the increasing processing power and electrothermal load of IT digital systems, traditional air-cooling systems are no longer sufficient to meet the heat exchange requirements of processors. Immersion liquid cooling systems, which submerge IT equipment in non-conductive coolant, are gradually becoming a new technology for processor heat dissipation. In the market for immersion liquid cooling materials, synthetic silicone oil has advantages over more commonly used liquid cooling media such as mineral oil and fluorocarbons, including being more environmentally friendly, having better liquid cooling performance, and lower cost. However, its low flash point and compatibility issues have always limited its application development. Summary of the Invention

[0003] To address the aforementioned technical problems in the synthesis of silicone oil, this invention synthesizes a fluoroether-modified siloxane, which possesses excellent dielectric properties, a high open flash point, and superior compatibility, showing promising development prospects in the field of immersion liquid cooling.

[0004] The technical solution adopted in this invention is: This invention discloses a fluoroether-modified siloxane, which is a chain silicone oil, wherein the main chain is a siloxane with siloxy groups at the end and the side chains are hydrocarbon chains modified with fluoroether structures. The average chemical structure of the fluoroether-modified siloxane is as follows:

[0005] Where m is selected from integers 1-200, n is selected from integers 1-250, and x is selected from integers 1-200; Q is -CH3 or -CF3, R0 indicates a straight-chain alkyl group, and R... ƒ It is represented by a perfluoropolyether group.

[0006] Furthermore, m is selected from an integer from 1 to 20; preferably, m is selected from an integer from 1 to 10; even more preferably, m is selected from an integer from 1 to 5.

[0007] n is selected from an integer from 1 to 20; preferably, n is selected from an integer from 1 to 10; more preferably, n is selected from an integer from 1 to 5.

[0008] x is selected from an integer from 1 to 15; preferably, x is selected from an integer from 1 to 10; even more preferably, x is selected from an integer from 1 to 5.

[0009] Furthermore, the R0 structure is: C z H 2z+1 - where z is selected from an integer from 1 to 30; preferably an integer from 1 to 20.

[0010] Furthermore, Rƒ The structure is: CF3CF2[CF2OCF(CF3)] y - where y is an integer selected from 1 to 15; preferably an integer from 1 to 6.

[0011] Furthermore, the fluoroether-modified siloxane has a dielectric constant above 2.0, an open-cup flash point above 200°C, and a breakdown voltage above 40 kV·mm. -1 The thermal conductivity is above 0.07 W·(m·K). -1 above.

[0012] This invention also discloses a method for preparing the above-mentioned fluoroether-modified siloxane: To prepare a fluoroether-modified siloxane with Z value ≥ 2 in R0, the following steps are used: After the first hydrogen-containing silicone oil is mixed with the catalyst and heated, a fluorinated olefin CF3CF2[CF2OCF(CF3)] is added. y (CH2) x- 2CH=CH2 undergoes a hydrosilylation reaction. After removing unreacted hydrogen-containing silicone oil, a fluorinated siloxane intermediate is obtained. The fluorinated siloxane intermediate is then mixed with a catalyst, heated, and then α-olefin is introduced. The mixture is heated under reflux to carry out a hydrosilylation reaction. After the reaction, the reaction solution is purified to obtain the fluorinated ether modified siloxane. The first hydrogen-containing silicone oil has the following structural formula:

[0013] The specific reaction process is as follows:

[0014] To prepare a fluoroether-modified siloxane with a Z value of 1, the following steps are taken: After mixing and heating the second hydrogen-containing silicone oil with the catalyst, a fluorinated olefin was added to carry out a hydrosilylation reaction. After the reaction, the reaction solution was purified to obtain the fluorinated ether modified siloxane. The second hydrogen-containing silicone oil has the following structural formula:

[0015] The specific reaction process is as follows:

[0016] Furthermore, the hydrosilylation reaction is carried out at a temperature of 60-100°C and a reaction time of 2-8 h under normal pressure; preferably, the hydrosilylation reaction is carried out at a temperature of 80-100°C and a reaction time of 4-6 h.

[0017] Furthermore, the catalyst is a platinum-based catalyst, and the amount of catalyst used accounts for 1500-3500 ppm of the total reaction system; preferably, the amount of catalyst used accounts for 1800-2300 ppm of the total reaction system.

[0018] Furthermore, when z≥2, the equivalent ratio of Si-H in the first hydrogen-containing silicone oil to the total C=C in the fluorinated olefin is 2:1 to 2:1.2; preferably, the equivalent ratio of Si-H in the first hydrogen-containing silicone oil to the total C=C in the α-olefin is 2:1 to 2:1.05; the equivalent ratio of Si-H in the fluorinated siloxane intermediate to the C=C in the α-olefin is 1:1 to 1:1.5; preferably 1:1 to 1:1.05.

[0019] When z=1, the equivalent ratio of Si-H in the second hydrogen-containing silicone oil to the total C=C in the fluorinated olefin is 1:1 to 1:1.5; preferably, the equivalent ratio of Si-H in the second hydrogen-containing silicone oil to the total C=C in the fluorinated olefin is 1:1 to 1:1.05.

[0020] Furthermore, the purification method is vacuum distillation, with a temperature of 140-240℃ and a pressure of 0-30 Pa.

[0021] Furthermore, the fluorinated olefin is selected from R. ƒ (CH2) x-2 CH=CH2, where R ƒ It is a perfluoropolyether with the structure CF3CF2[CF2OCF(CF3)]. y - where y = 1-15, preferably an integer from 1 to 6.

[0022] The aforementioned fluoroether-modified siloxanes are mainly used in the field of liquid cooling.

[0023] The synthesized fluoroether-modified siloxane was found to have good liquid cooling performance due to its superior dielectric constant and thermal conductivity.

[0024] The synthesized fluoroether-modified siloxane was found to have a high open flash point and breakdown voltage in relevant performance tests, which makes it highly safe in immersion liquid cooling systems.

[0025] The synthesized fluoroether-modified siloxane was found to have strong anti-swelling ability against silicone rubber and EPDM rubber in compatibility performance tests.

[0026] The fluoroether-modified siloxanes proposed in this invention exhibit better thermal conductivity and compatibility compared to existing fluorocarbon compounds. The hydrosilylation process employed in the synthesis method proposed in this invention offers advantages such as low synthesis cost, simple process, and reduced waste generation, making it more suitable for industrial-scale production in related fields (heat transfer oils, coolants, etc.). Attached Figure Description

[0027] Figure 1 The fluoroether-modified siloxane synthesized in Example 1 19 F NMR spectrum. Detailed Implementation

[0028] The present invention will be further illustrated by specific embodiments below, but this is not a limitation of the present invention. Those skilled in the art can make various modifications or improvements based on the basic idea of ​​the present invention, but as long as they do not depart from the basic idea of ​​the present invention, they are all within the scope of the present invention. Example 1: The fluoroether-modified siloxane of this application is synthesized using the following method, wherein m=1, n=1, x=3, and Q is -CH3; wherein the R0 group is C6H. 13 -, R ƒ The functional group is CF3CF2[CF2OCF(CF3)]2-.

[0029] Step 1: In a 500 mL three-necked flask, 282 g of the first hydrogen-containing silicone oil (CH3)3Si-[-O-HSi(CH3)-]2-OSi(CH3)3 and 1.098 g of platinum-based catalyst were added sequentially. The three ports of the flask were connected to a sealed stopcock, a high-efficiency reflux condenser, and a thermometer, respectively. The temperature inside the flask jacket was controlled at 10°C using a refrigeration cycler. After nitrogen purging, the mixture was heated to 85°C with stirring. Once the temperature inside the reactor reached 85°C, 258 g of the fluorinated olefin CF3CF2[CF2OCF(CF3)]2CH2CH=CH2 was slowly added dropwise, while controlling the temperature inside the reactor to not exceed 100°C. After the addition was completed, the temperature was controlled at 90°C and heated with stirring for 6 h. After the reaction was completed, unreacted hydrogen-containing silicone oil and fluorinated olefin were removed by vacuum distillation to obtain a fluorinated siloxane intermediate (containing unreacted Si-H in its structure).

[0030] Step 2: In a new reaction apparatus (identical to the one described above), add 528 g of a fluorosiloxane intermediate and 1.24 g of a platinum-based catalyst sequentially, followed by nitrogen purging. Once the internal temperature reaches 85°C, slowly add 84.16 g of n-hexene dropwise, controlling the internal temperature to not exceed 100°C. After the addition is complete, maintain the temperature at 90°C and continue heating and stirring for 4 hours.

[0031] Step 3: The above reaction solution is distilled and purified under conditions of 240℃ and 20 Pa vacuum, and the high-boiling component (boiling range: 180-220℃) is collected with a purity of over 97%.

[0032] Example 2: The fluoroether-modified siloxane of this application was synthesized using the following method, wherein m=1, n=1, x=3, and Q is -CH3; wherein the R0 group is -CH3, and R... ƒ The group CF3CF2[CF2OCF(CF3)]2-.

[0033] Step 1: In a 500 mL three-necked flask, add 296.63 g of the second hydrogen-containing silicone oil (CH3)3SiO-Si(CH3)2-O-HSi(CH3)-OSi(CH3)3 and 1.65 g of platinum-based catalyst sequentially. Connect the three ports of the flask to a sealed piston, a high-efficiency reflux condenser, and a thermometer, respectively. Use a refrigeration cycler to maintain the temperature inside the flask jacket at 10°C. After nitrogen purging, start heating and stirring at 85°C. Once the temperature inside the reactor reaches 85°C, slowly add 529.2 g of the fluorinated olefin CF3CF2[CF2OCF(CF3)]2CH2CH=CH2, controlling the temperature inside the reactor to not exceed 100°C. After the addition is complete, maintain the temperature at 90°C and continue heating and stirring for 6 hours.

[0034] Step 2: The above reaction solution is distilled and purified under conditions of 200℃ and 20 Pa vacuum, and the high-boiling component (boiling range: 200-230℃) is collected with a purity of over 98%.

[0035] Example 3 The fluoroether-modified siloxane of this application is synthesized using the following method, wherein m=10, n=10, x=5, and Q is -CH3; wherein the R0 group is C6H. 13 -, R ƒ The functional group is CF3CF2[CF2OCF(CF3)]2-.

[0036] The preparation method is the same as in Example 1, except that the first hydrogen-containing silicone oil used is (CH3)3Si-[-O-HSi(CH3)-]. 20 -OSi(CH3)3, the fluorinated olefin is selected as CF3CF2[CF2OCF(CF3)]2(CH2)3CH=CH2, and the reaction conditions such as the ratio of hydrogen-containing silicone oil to olefin, reaction temperature and catalyst equivalent are the same as in Example 1.

[0037] Example 4 The fluoroether-modified siloxane of this application is synthesized using the following method, wherein m=10, n=10, x=5, and Q is -CH3; wherein the R0 group is C8H. 17-,R ƒ The functional group is CF3CF2[CF2OCF(CF3)]2-.

[0038] The preparation method is the same as in Example 3, the only difference being the selected ingredients. α -The olefin is n-octene.

[0039] Example 5 The fluoroether-modified siloxane of this application is synthesized using the following method, wherein m=1, n=1, x=3, and Q is -CF3; wherein the R0 group is C6H. 13 -,R ƒ The functional group is CF3CF2[CF2OCF(CF3)]2-.

[0040] The preparation method is the same as in Example 1, except that the first hydrogen-containing silicone oil is (CF3)3Si-[-O-HSi(CH3)-]2-OSi(CF3)3.

[0041] Table 1 lists the relevant properties of the five synthesized fluoroether-modified siloxanes, including dielectric properties, kinematic viscosity, and open-cup flash point. For comparative purposes, the liquid cooling performance of KEY-138 electronic fluorinated liquid from Zhongke Micro New Materials and ICL-1100 organosilicon coolant from Dow Chemical is compared with the aforementioned invention.

[0042] Table 1

[0043] Table 2 shows the compatibility performance of the two synthesized fluoroether-modified siloxanes. The specific method used was as follows: EPDM rubber and silicone rubber fragments (50×5×2 mm) of a certain size were cut as test samples. The initial length and initial weight of each sample were recorded. The test samples were completely immersed in the test fluid in a container, which was then sealed and heated to 50°C in an oven. After storing at 50°C for four months, the samples were removed, and both sides were blotted dry with absorbent paper. The sample length and weight were recorded. The change in length and weight relative to the initial immersion was determined: a length increase greater than 15% (relative to the initial length) or a weight increase greater than 50% (relative to the initial weight) constituted "significant swelling," and the sample was considered unqualified.

[0044] The compatibility performance of this invention and Dow Chemical's PDMS silicone oil was compared, and the comparison results are shown in the table below: Table 2

[0045] In the comparison of liquid cooling performance, it was found that compared with KEY-138, which is mainly composed of fluorocarbon compounds, the fluoroether-modified siloxane synthesized in this invention has a higher thermal conductivity and a better advantage in liquid cooling heat transfer efficiency. Compared with ICL-1100, which is mainly composed of organosilicon, the lower kinematic viscosity and dielectric constant can provide better heat transfer efficiency and dielectric insulation in the liquid cooling system. The higher open flash point and breakdown voltage ensure that this invention has a high safety factor in data center liquid cooling applications.

[0046] Comparison of compatibility performance revealed that, compared with fluorine-free PDMS silicone oil, the two fluoroether-modified siloxanes had a smaller impact on the swelling of the two types of test materials, and both were within the requirements of the compatibility test.

[0047] Although the present invention has been described in detail above with reference to the preferred embodiments, those skilled in the art should understand that any improvements and modifications made to the present invention without departing from the spirit and intent of the invention are still within the scope of protection claimed by the present invention.

Claims

1. A fluoroether-modified siloxane, characterized in that, The average chemical structure is: Where m is selected from integers 1-200, n is selected from integers 1-250, and x is selected from integers 1-200; Q is -CH3 or -CF3, R0 indicates a straight-chain alkyl group, and R... ƒ It is represented by a perfluoropolyether group.

2. The fluoroether-modified siloxane according to claim 1, characterized in that, m is selected from integers from 1 to 20, n is selected from integers from 1 to 20, and x is selected from integers from 1 to 15.

3. The fluoroether-modified siloxane according to claim 1, characterized in that, The structure of R0 is: C z H 2z+1 -, where z is an integer selected from 1 to 30; R ƒ The structure is: CF3CF2[CF2OCF(CF3)] y - where y is an integer selected from 1 to 15.

4. The fluoroether-modified siloxane according to claim 3, characterized in that, z is selected from integers from 1 to 20, and y is selected from integers from 1 to 6.

5. The fluoroether-modified siloxane according to claim 1, characterized in that, The fluoroether-modified siloxane has a dielectric constant above 2.0, an open-cup flash point above 200℃, and a breakdown voltage above 40 kV·mm. -1 The thermal conductivity is above 0.07 W·(m·K). -1 above.

6. A method for preparing the fluoroether-modified siloxane according to any one of claims 1 to 5, characterized in that, To prepare fluoroether-modified siloxanes with a Z value ≥ 2, the following steps are taken: After the first hydrogen-containing silicone oil is mixed with the catalyst and heated, a fluorinated olefin is added to carry out a hydrosilylation reaction. After removing the unreacted hydrogen-containing silicone oil, a fluorinated siloxane intermediate is obtained. The fluorinated siloxane intermediate is then mixed with the catalyst and heated, and then α-olefin is introduced. The mixture is heated under reflux to carry out a hydrosilylation reaction. After the reaction, the reaction solution is purified to obtain the fluorinated ether modified siloxane. To prepare a fluoroether-modified siloxane with a Z value of 1, the following steps are taken: After mixing and heating the second hydrogen-containing silicone oil with the catalyst, a fluorinated olefin was added to carry out a hydrosilylation reaction. After the reaction, the reaction solution was purified to obtain the fluorinated ether modified siloxane. The first hydrogen-containing silicone oil has the following structural formula: The second hydrogen-containing silicone oil has the following structural formula: 。 7. The method for preparing fluoroether-modified siloxane according to claim 6, characterized in that, The hydrosilylation reaction is carried out at a temperature of 60-100℃ and for a time of 2-8 h. The catalyst is a platinum-based catalyst, and the amount of catalyst used accounts for 1500-3500 ppm of the total reaction system; The total C=C equivalent ratio of Si-H in the first hydrogen-containing silicone oil to that in the fluorinated olefin is 2:1-2:1.2, and the C=C equivalent ratio of Si-H in the fluorinated siloxane intermediate to that in the α-olefin is 1:1-1:1.

5. The equivalent ratio of Si-H to C=C in the fluorinated olefin in the second hydrogen-containing silicone oil is 1:1 to 1:1.

5. The purification method is vacuum distillation, with a temperature of 140-240℃ and a pressure of 0-30 Pa.

8. The method for preparing fluoroether-modified siloxane according to claim 7, characterized in that, The hydrosilylation reaction is carried out at a temperature of 80-100℃ for 4-6 hours. The catalyst is used in an amount of 1800-2300 ppm of the total reaction system; The preferred ratio of Si-H to the total C=C equivalent in the first hydrogen-containing silicone oil is 2:1 to 2:1.05; The preferred equivalent ratio of Si-H to C=C in α-olefins in fluorosiloxane intermediates is 1:1 to 1:1.05; The preferred equivalent ratio of Si-H to C=C in the second hydrogen-containing silicone oil is 1:1 to 1:1.

05.

9. The method for preparing fluoroether-modified siloxane according to claim 6, characterized in that, The fluorinated olefin is selected from R. ƒ (CH2) x-2 CH=CH2, where R ƒ It is a perfluoropolyether with the structure CF3CF2[CF2OCF(CF3)]. y - where y = 1-15, preferably 1-6.

10. The application of the fluoroether-modified siloxane according to any one of claims 1-5 or the fluoroether-modified siloxane prepared by the method according to any one of claims 6-9 in the field of liquid cooling.

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