An oil-free, single-component thermally conductive gel and its preparation method

Abstract

This invention discloses a one-component thermally conductive gel and its preparation method. The thermally conductive gel is prepared from raw materials comprising the following components: 100 parts of modified vinyl silicone oil, 20-60 parts of modified side-hydrogen-containing silicone oil, 2400-3200 parts of thermally conductive powder, an inhibitor, and a platinum catalyst. The modified vinyl silicone oil has a viscosity of 10 mPa·s to 200 mPa·s and a vinyl content of 0.1 wt% to 1.5 wt%. The modified side-hydrogen-containing silicone oil has a hydrogen content of 0.05 wt% to 0.3 wt% and a viscosity of 50 to 500 mPa·s. The one-component thermally conductive gel prepared by this invention, by using modified side-hydrogen-containing silicone oil and modified vinyl silicone oil as the pre-curing system of the one-component thermally conductive gel, and by controlling the silicon-hydrogen ratio, has the advantages of high extrusion rate and zero oil seepage.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to thermally conductive gels, and particularly to an oil-free, single-component thermally conductive gel and its preparation method. Background Technology

[0002] With the rapid development of industries such as 5G communications and new energy vehicles, thermal management materials have ushered in unprecedented opportunities. As electronic components become increasingly powerful, thermal management becomes more crucial, placing higher demands on thermal management materials. Organosilicon thermal conductive gel, as a novel thermal interface material, has attracted significant industry attention due to its combination of the advantages of thermal pads and thermal grease.

[0003] One-component thermal conductive gels, due to their ease of application (dispensing is possible) and resistance to powdering, can replace thermal grease and are widely used in communication equipment such as base stations, 3C terminals, and automotive electronic control systems. However, unlike two-component thermal conductive gels, which cure as an elastomer, one-component thermal conductive gels, due to dispensing speed considerations, generally cure as a paste rather than a fully cross-linked elastomer, resulting in a very low cross-linking density. This low cross-linking density inevitably leads to some polymers, such as vinyl silicone oil, remaining in a free state without reacting. Some manufacturers even use only non-reactive methyl silicone oil mixed with powder, without any pre-curing reaction, which can easily lead to oil seepage and oil-powder separation with long-term use, affecting heat dissipation reliability. One-component thermal conductive gels often use high-molecular-weight resins combined with thermally conductive powders, undergoing pre-curing to form a cross-linked network structure to achieve low oil seepage characteristics.

[0004] Chinese patent application CN113897063A discloses a curable single-component thermally conductive gel and its preparation method. It achieves the advantages of long-term storage at low temperatures and rapid curing at room temperature by using hydrogen-containing polysiloxane, peroxide and thermally conductive filler, without the need for special heating.

[0005] Chinese patent application CN115403933A discloses a high-extrusion, low-oil-permeability single-component thermally conductive gel and its preparation method. The method utilizes vinyl silicone oil to impart excellent flowability and adhesion to the thermally conductive gel, resulting in low thermal resistance and superior thermal conductivity. Adding thermally conductive powders alumina and zinc oxide further enhances the gel's heat transfer performance. Surface treatment of boron nitride increases its porosity, improving its adsorption capacity for silicone oil molecules and reducing the likelihood of silicone oil molecules precipitating from the system and causing oil permeation. Simultaneously, the structure of boron nitride itself acts as a lubricant in the thermally conductive gel, reducing internal and external friction and increasing the extrusion and application rates, thus ensuring that the thermally conductive gel possesses both high extrusion rate and low oil permeation rate. This technology requires surface treatment of boron nitride with a boron trifluoride diethyl ether complex to increase its porosity, thereby enhancing its adsorption capacity for silicone oil molecules. Simultaneously, the lubricating properties of boron nitride in the thermally conductive gel system result in a better extrusion rate and lower oil seepage rate. However, adding boron nitride is typically difficult, and its high oil absorption value means that the risk of oil seepage remains with long-term use.

[0006] Currently, single-component thermally conductive gels that can achieve zero oil seepage are extremely rare. Summary of the Invention

[0007] Based on this, the present invention aims to provide a single-component thermally conductive gel with zero oil seepage and high extrusion rate, and a method for preparing the same.

[0008] A first aspect of the present invention is to provide a one-component thermally conductive gel, which, by weight, is prepared from raw materials comprising the following components:

[0009] 100 parts of modified vinyl silicone oil,

[0010] 20-60 parts of modified hydrogen-containing silicone oil.

[0011] 2400-3200 parts of thermally conductive powder

[0012] Inhibitor 0.01-0.2 parts,

[0013] Platinum catalyst 2ppm-10ppm (based on platinum mass);

[0014] The modified vinyl silicone oil is prepared by hydrosilylation reaction of terminal vinyl silicone oil and hydrogen-containing silane in the presence of a platinum catalyst, wherein the hydrogen-containing silane is trimethoxysilane or triethoxysilane; the modified vinyl silicone oil has a viscosity of 10 mPa·s to 200 mPa·s and a vinyl content of 0.1wt% to 1.5wt%.

[0015] The modified side-hydrogenated silicone oil is prepared by a hydrosilylation reaction of side-hydrogenated silicone oil and 1-olefins with 8-16 carbons in the presence of a platinum catalyst. The modified side-hydrogenated silicone oil has a hydrogen content of 0.05wt% to 0.3wt% and a viscosity of 50 to 500 mPa·s.

[0016] In some of these embodiments, the viscosity of the modified vinyl silicone oil is 30 mPa·s to 100 mPa·s, more preferably 50 mPa·s to 100 mPa·s.

[0017] In some of these embodiments, the modified hydrogen-containing silicone oil has a hydrogen content of 0.1wt% to 0.2wt% and a viscosity of 100 mPa·s to 300 mPa·s.

[0018] In some embodiments, the modified side-hydrogenated silicone oil is prepared by hydrosilylation reaction of side-hydrogenated silicone oil and 1-olefins with 8-16 carbons in the presence of a platinum catalyst. Preferably, 1-olefins with 10-14 carbons are used.

[0019] In some of the embodiments, the hydrogen content of the modified hydrogen-containing silicone oil prepared is 0.15wt% to 0.3wt%, and the viscosity is 50 to 500 mPa·s, preferably 0.15wt% to 0.25wt%, and the viscosity is 100 to 300 mPa·s.

[0020] In some of these embodiments, the molar ratio of the silane group of the side-hydrogen-containing silicone oil to the vinyl group of the 1-olefin with 8-16 carbons is (3-5):1.

[0021] In some of the embodiments, the modified vinyl silicone oil is prepared with a viscosity of 10 mPa·s to 200 mPa·s, preferably 50 mPa·s to 200 mPa·s, and a vinyl content of 0.6 wt% to 2.0 wt%.

[0022] In some embodiments, the molar ratio of silane groups in the modified hydrogen-containing silicone oil to vinyl groups in the modified vinyl silicone oil is between 1.5 and 3.0, preferably between 2.0 and 3.0.

[0023] In some embodiments, when the modified vinyl silicone oil is 100 parts, the modified hydrogen-containing silicone oil is 30-55 parts; and / or the thermally conductive powder is 2600-3100 parts.

[0024] In some of these embodiments, when the modified vinyl silicone oil is 100 parts, the inhibitor is 0.1-0.2 parts; and / or the platinum catalyst is 3-8 ppm.

[0025] In some of these embodiments, the thermally conductive powder is one or a combination of aluminum oxide, zinc oxide, magnesium oxide, aluminum nitride, and boron nitride.

[0026] In some of the embodiments, the platinum catalyst is one or a combination of chloroplatinic acid, chloroplatinic acid-isopropanol complex, and cassette catalyst.

[0027] In some of these embodiments, the inhibitor is one or a combination of 1-ethynyl-1-cyclohexanol, tetramethyltetravinylcyclotetrasiloxane, 2-methyl-3-butynyl-2-ol, 3-methyl-1-hexynyl-3-ol, 3,5-dimethyl-1-hexynyl-3-ol, and 3-methyl-1-dodecynyl-3-ol.

[0028] A second aspect of the present invention is to provide a method for preparing the thermally conductive gel, comprising the following steps:

[0029] (1) The modified vinyl silicone oil and the modified hydrogen-containing silicone oil are put into a mixer and stirred and mixed evenly. Then the thermally conductive powder is added in batches. After the addition is completed, the temperature is raised to 70℃~90℃ and stirred and reacted for 1-3 hours to obtain the adhesive. The adhesive is then cooled to room temperature.

[0030] (2) Add the inhibitor to a mixer and mix thoroughly;

[0031] (3) Add the platinum catalyst, stir and mix evenly, and remove bubbles by vacuum to obtain a mixture;

[0032] (4) The mixture obtained in step (3) is heated and pre-cured to obtain the single-component thermally conductive gel.

[0033] The preparation method of the present invention uses modified side-containing hydrogen silicone oil and modified vinyl silicone oil as the pre-curing system of a single-component thermal conductive gel, which together with other components including thermally conductive powder form a whole. After pre-curing, a branched structure is formed, and the silicon-hydrogen ratio is controlled, thereby obtaining a single-component thermal conductive gel with high extrusion rate and no oil leakage. Compared with existing single-component thermal conductive gels, the single-component thermal conductive gel of the present invention has the following beneficial effects: (1) Modified side-containing hydrogen silicone oil is used as the main chain, and modified vinyl silicone oil is used as the side chain extender of modified side-containing hydrogen silicone oil. After pre-curing, a branched structure is formed, which is completely different from the straight chain structure or cross-linked network structure after pre-curing of traditional single-component thermal conductive gel technology. We found that, through appropriate silicon-hydrogen ratio design, this branched structure not only has high extrudability, but also all modified vinyl silicone oil participates in the reaction, which can minimize the release and exudation of unreacted polymers; (2) The modified side hydrogen-containing silicone oil contains long-chain alkyl groups (e.g., 8-16 carbons), which can effectively modify the thermally conductive powder and improve its dispersibility. Without the use of small molecule powder modifiers, it not only has good extrudability, but also avoids the precipitation of powder modifiers; (3) The modified vinyl silicone oil used contains alkoxy groups, which can form chemical bonds or hydrogen bonds with the hydroxyl groups on the surface of the thermally conductive powder, enhancing the bonding force between the polymer system and the thermally conductive powder, and further reducing oil leakage. In summary, the branched network structure formed after pre-curing, combined with the anchoring effect of alkoxy groups in the modified vinyl silicone oil on the powder, and the "zero" addition of small molecule powder modifiers, work synergistically to achieve zero oil leakage. Detailed Implementation

[0034] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments are merely illustrative of the present invention and should not be construed as limiting the invention.

[0035] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention.

[0036] The terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, apparatus, product, or device that includes a series of steps is not limited to the steps or modules listed, but may optionally include steps not listed, or may optionally include other steps inherent to such process, method, product, or device.

[0037] In this invention, "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0038] The following are specific examples.

[0039] Unless otherwise specified, the viscosity in the following examples refers to the viscosity at 25°C; unless otherwise specified, "parts" refers to parts by weight.

[0040] The modified vinyl silicone oil in the single-component thermally conductive gel of the present invention can be prepared by a hydrosilylation reaction of terminal vinyl silicone oil (viscosity of 10 mPa·s to 200 mPa·s, preferably 50 mPa·s to 200 mPa·s, vinyl content of 0.6 wt% to 2.0 wt%) and a hydrogen-containing silane in the presence of a platinum catalyst.

[0041] The reaction formula is as follows:

[0042]

[0043] Each molecule of the modified vinyl silicone oil has a Si-Vi group at one end and a Si(OR)3 group at the other end, where Vi is vinyl and OR is methoxy or ethoxy. In the following examples, the modified vinyl silicone oil used has a methoxy group as its OR.

[0044] In practical applications, the viscosity is controlled at 10 mPa·s to 200 mPa·s, preferably 30 mPa·s to 100 mPa·s, and the vinyl content is 0.5wt% to 1.0wt%.

[0045] The modified side-hydrogenated silicone oil is prepared by a hydrosilylation reaction of side-hydrogenated silicone oil (hydrogen content of 0.15wt% to 0.3wt%, viscosity of 50 to 500 mPa·s, preferably hydrogen content of 0.15wt% to 0.25wt%, viscosity of 100 to 300 mPa·s) and 1-olefins with 8 to 16 carbon atoms in the presence of a platinum catalyst, as shown in the following reaction formula:

[0046] .

[0047] Wherein, n is 5-13, preferably 7-11. In the following examples, n in the modified hydrogen-containing silicone oil is 9.

[0048] The hydrogen content of the modified hydrogen-containing silicone oil is controlled to be 0.05wt% to 0.3wt%, preferably 0.1wt% to 0.2wt%; the viscosity is 50 to 500 mPa·s, preferably 100 mPa·s to 300 mPa·s.

[0049] The modified hydrogen-containing silicone oil has the following structure:

[0050]

[0051] The thermally conductive gel described in the following examples can be prepared by referring to the following method.

[0052] The preparation method of the single-component thermally conductive gel includes the following steps:

[0053] (1) According to the specific amount, the modified vinyl silicone oil and the modified side hydrogen-containing silicone oil are put into a planetary mixer and stirred for about 5 minutes to mix evenly. The thermally conductive powder is added in three batches. After the addition is completed, the temperature is raised to about 80°C and reacted for about 2 hours. The resulting rubber material is cooled to room temperature.

[0054] (2) Add the inhibitor to a planetary mixer and mix for about 20 minutes;

[0055] (3) The catalyst is added to a planetary mixer and stirred for 30 minutes. Vacuum is then used to remove air bubbles to obtain a mixture.

[0056] (4) The resulting mixture is packaged and pre-cured at 70°C for about 3 hours to obtain the single-component thermal conductive gel.

[0057] Example 1

[0058] The single-component thermally conductive gel composition described in this embodiment has the following raw material composition:

[0059]

[0060] The molar ratio of silanol groups in the side-end hydrogen-containing silicone oil to vinyl groups in the single-end vinyl silicone oil is 2.97.

[0061] The method for preparing the modified vinyl silicone oil:

[0062] (1) Add 100 parts of vinyl-terminated silicone oil with a viscosity of 50 cP and a vinyl content of 2.0 wt%, 5 ppm (based on Pt content) of Castel catalyst and 200 parts of toluene to a three-necked flask equipped with a stirrer, reflux condenser, dropping funnel and thermometer, and stir until homogeneous.

[0063] (2) Slowly add 4.5 parts of trimethoxysilane to the above mixture, and after the addition is complete, heat to 80°C and reflux for 1 hour;

[0064] (3) After the reaction is complete, toluene is evaporated and the catalyst is removed by activated carbon adsorption to obtain modified vinyl silicone oil with a viscosity of 50 cP and a vinyl content of 1.0 wt%.

[0065] The molar ratio of vinyl groups to trimethoxysilane groups in the vinyl-terminated silicone oil is 2:1.

[0066] The method for preparing the modified hydrogen-containing silicone oil:

[0067] (1) In a reactor equipped with a stirrer, reflux condenser, dropping funnel and thermometer, first add 100 parts of side-containing hydrogen silicone oil with a viscosity of 300 cP and a hydrogen content of 0.25 wt%, 200 parts of toluene and 5 ppm (based on Pt content) of platinum catalyst, and stir evenly.

[0068] (2) Slowly add 7.9 parts of 1-dodecene to the above mixture, and after the addition is complete, heat to 80°C and reflux for 1 hour;

[0069] (3) After the reaction is complete, toluene is evaporated and the catalyst is removed by activated carbon adsorption to obtain modified hydrogen-containing silicone oil with a viscosity of 300 cP and a hydrogen content of 0.2 wt%.

[0070] The molar ratio of the silanol group to the vinyl group of 1-dodecene in the side-containing hydrogen silicone oil is 5:1.

[0071] Example 2

[0072] The single-component thermally conductive gel composition described in this embodiment has the following raw material composition:

[0073]

[0074] The molar ratio of silanol groups in the side-end hydrogen-containing silicone oil to vinyl groups in the single-end vinyl silicone oil is 1.82.

[0075] The method for preparing the modified vinyl silicone oil:

[0076] (1) Add 100 parts of vinyl-terminated silicone oil with a viscosity of 200 cP and a vinyl content of 0.6 wt%, 5 ppm (based on Pt content) of Castel catalyst and 200 parts of toluene to a three-necked flask equipped with a stirrer, reflux condenser, dropping funnel and thermometer, and stir until homogeneous.

[0077] (2) Slowly add 1.4 parts of trimethoxysilane to the above mixture, and after the addition is complete, heat to 80°C and reflux for 1 hour;

[0078] (3) After the reaction is complete, toluene is evaporated and the catalyst is removed by activated carbon adsorption to obtain modified vinyl silicone oil with a viscosity of 200 cP and a vinyl content of 0.3 wt%.

[0079] The vinyl-to-trimethoxysilane molar ratio of the hydroxyl group to the vinyl group in the vinyl-terminated silicone oil is 2:1. The modified hydrogen-containing silicone oil is prepared as follows:

[0080] (1) In a reactor equipped with a stirrer, reflux condenser, dropping funnel and thermometer, first add 100 parts of side-containing hydrogen silicone oil with a viscosity of 100 cP and a hydrogen content of 0.15 wt%, 200 parts of toluene and 5 ppm (based on Pt content) of platinum catalyst, and stir evenly.

[0081] (2) Slowly add 7.9 parts of 1-dodecene to the above mixture, and after the addition is complete, heat to 80°C and reflux for 1 hour;

[0082] (3) After the reaction is complete, toluene is evaporated and the catalyst is removed by activated carbon adsorption to obtain modified hydrogen-containing silicone oil with a viscosity of 100 cP and a hydrogen content of 0.1 wt%.

[0083] The molar ratio of the silanol group to the vinyl group of 1-dodecene in the side-containing hydrogen silicone oil is 3:1.

[0084] Example 3

[0085] The single-component thermally conductive gel composition described in this embodiment has the following raw material composition:

[0086]

[0087] The molar ratio of silanol groups in the side-containing hydrogen silicone oil to vinyl groups in the single-ended vinyl silicone oil is 2.03.

[0088] The method for preparing the modified vinyl silicone oil:

[0089] (1) Add 100 parts of vinyl-terminated silicone oil with a viscosity of 100 cP and a vinyl content of 1.0 wt%, 5 ppm (based on Pt content) of Castel catalyst and 200 parts of toluene to a three-necked flask equipped with a stirrer, reflux condenser, dropping funnel and thermometer, and stir until homogeneous.

[0090] (2) Slowly add 2.3 parts of trimethoxysilane to the above mixture, and after the addition is complete, heat to 80°C and reflux for 1 hour;

[0091] (3) After the reaction is complete, toluene is evaporated and the catalyst is removed by activated carbon adsorption to obtain modified vinyl silicone oil with a viscosity of 100 cP and a vinyl content of 0.5 wt%.

[0092] The molar ratio of vinyl groups to trimethoxysilane groups in the vinyl-terminated silicone oil is 2:1.

[0093] The method for preparing the modified hydrogen-containing silicone oil:

[0094] (1) In a reactor equipped with a stirrer, reflux condenser, dropping funnel and thermometer, first add 100 parts of side-containing hydrogen silicone oil with a viscosity of 200 cP and a hydrogen content of 0.20 wt%, 200 parts of toluene and 5 ppm (based on Pt content) of platinum catalyst, and stir until uniform.

[0095] (2) Slowly add 7.9 parts of 1-dodecene to the above mixture, and after the addition is complete, heat to 80°C and reflux for 1 hour;

[0096] (3) After the reaction is complete, toluene is evaporated and the catalyst is removed by activated carbon adsorption to obtain modified hydrogen-containing silicone oil with a viscosity of 200 cP and a hydrogen content of 0.15 wt%.

[0097] The molar ratio of the silanol group to the vinyl group of 1-dodecene in the side-containing hydrogen silicone oil is 4:1.

[0098] Example 4

[0099] The single-component thermally conductive gel composition described in this embodiment has the following raw material composition:

[0100]

[0101] The molar ratio of silanol groups in the side-containing hydrogen silicone oil to vinyl groups in the single-ended vinyl silicone oil is 2.03.

[0102] The modified vinyl silicone oil is prepared using the same method as in Example 3.

[0103] The method for preparing the modified hydrogen-containing silicone oil is the same as in Example 3.

[0104] Example 5

[0105] The single-component thermally conductive gel composition described in this embodiment has the following raw material composition:

[0106]

[0107] The molar ratio of silanol groups in the side-containing hydrogen silicone oil to vinyl groups in the single-ended vinyl silicone oil is 2.03.

[0108] The modified vinyl silicone oil is prepared using the same method as in Example 3.

[0109] The method for preparing the modified hydrogen-containing silicone oil:

[0110] (1) In a reactor equipped with a stirrer, reflux condenser, dropping funnel and thermometer, first add 100 parts of side-containing hydrogen silicone oil with a viscosity of 150 cP and a hydrogen content of 0.20 wt%, 200 parts of toluene and 5 ppm (based on Pt content) of platinum catalyst, and stir evenly.

[0111] (2) Slowly add 7.9 parts of 1-dodecene to the above mixture, and after the addition is complete, heat to 80°C and reflux for 1 hour;

[0112] (3) After the reaction is complete, toluene is evaporated and the catalyst is removed by activated carbon adsorption to obtain modified hydrogen-containing silicone oil with a viscosity of 150 cP and a hydrogen content of 0.15 wt%.

[0113] The molar ratio of the silanol group to the vinyl group of 1-dodecene in the side-containing hydrogen silicone oil is 4:1.

[0114] Comparative Example 1

[0115] The single-component thermally conductive gel composition described in this comparative example has the following raw material composition:

[0116]

[0117] The molar ratio of silanol groups in the hydrogen-terminated silicone oil to vinyl groups in the vinyl-terminated silicone oil is 0.41.

[0118] The specific preparation method includes the following steps:

[0119] (1) Add the vinyl-terminated silicone oil, hydrogen-terminated silicone oil and inhibitor into a planetary mixer and stir for 5 minutes to mix evenly. Add the modified thermally conductive powder in three batches and stir for 30 minutes after adding to mix evenly.

[0120] (2) The catalyst is added to a planetary mixer and stirred for 20 minutes, and then vacuumed to remove air bubbles;

[0121] (3) After dispensing, heat at 70°C for 3 hours to obtain a pre-cured single-component thermally conductive gel.

[0122] Comparative Example 2

[0123] The single-component thermally conductive gel composition in this comparative example has the following raw material composition:

[0124]

[0125] The molar ratio of silanol groups in the side-hydrogen-containing silicone oil to vinyl groups in the end-vinyl silicone oil is 0.27.

[0126] The specific preparation method includes the following steps:

[0127] (1) Add the terminal vinyl silicone oil, the side hydrogen-containing silicone oil and the inhibitor into a planetary mixer and stir for 5 minutes to mix evenly. Add the modified thermally conductive powder in three batches and stir for 30 minutes after adding to mix evenly.

[0128] (2) The catalyst is added to a planetary mixer and stirred for 20 minutes, and then vacuumed to remove air bubbles;

[0129] (3) After dispensing, heat at 70°C for 3 hours to obtain a pre-cured single-component thermally conductive gel.

[0130] Comparative Example 3

[0131] The single-component thermally conductive gel composition in this comparative example has the following raw material composition:

[0132]

[0133] The molar ratio of silanol groups in the side-hydrogen-containing silicone oil to vinyl groups in the end-vinyl silicone oil is 0.20.

[0134] Comparative Example 4

[0135] The single-component thermally conductive gel composition in this comparative example has the following raw material composition:

[0136]

[0137] The molar ratio of silanol groups in the side-hydrogen-containing silicone oil to vinyl groups in the end-vinyl silicone oil is 1.22.

[0138] Comparative Example 5

[0139] The single-component thermally conductive gel composition described in this embodiment has the following raw material composition:

[0140]

[0141] The molar ratio of silanol groups in the side-hydrogen-containing silicone oil to vinyl groups in the end-vinyl silicone oil is 4.45.

[0142] The thermally conductive gel compositions of the above examples and comparative examples were tested respectively:

[0143] 1. Thermal conductivity: Measured according to ASTM D 5470 Characterization test for thermal conductivity properties of thin thermally conductive solid electrical insulating materials;

[0144] 2. Extrusion rate measurement method: Fill a 30cc syringe with rubber compound, set the air pressure to 0.6MPa, and record the extrusion volume (mass) in 1 minute.

[0145] 3. Oil seepage determination method: Take 10g of single-component thermal conductive gel, place it on filter paper, make a circular gel sample with a diameter of 3cm, bake at 120℃ for 7 days and calculate the oil seepage area (oil seepage area = maximum area of ​​oil seepage edge - area of ​​circular gel sample).

[0146] The test results are as follows:

[0147]

[0148] As shown in the table above, the oil-to-powder mass ratio in Examples 1-5 was 1:20 (i.e., the amount of thermally conductive powder was 20 times the sum of the amounts of modified vinyl silicone oil and modified side-hydrogen-containing silicone oil), and the thermal conductivity reached approximately 6.0 W / mK. This is due, on the one hand, to the branched structure formed after pre-curing, which is neither purely linear nor cross-linked, and on the other hand, to the design of a specific silicon-hydrogen ratio. This branched structure not only has a high extrusion rate (exceeding 30 g / min) but also excellent oil resistance. On the other hand, the modified side-hydrogen-containing silicone oil acts as a reactive polymer, and its dodecyl alkyl side chain makes it function as a powder modifier, thus avoiding the use of easily exuding small molecule powder modifiers such as dodecyltrimethoxysilane, thereby achieving zero oil leakage.

[0149] Comparative Example 1, compared to Examples 1-5, uses a pure chain-extended system of terminal vinyl silicone oil and terminal hydrogen-containing silicone oil, exhibiting an extrusion rate of only 21.3 g / min and an oil penetration area as high as 6.87 cm². 2 The oil seepage was severe; both Comparative Examples 2 and 3 used side-containing hydrogen silicone oil as a crosslinking agent, and their extrudability was far inferior to that of Examples 1-5, with the oil seepage area exceeding 4 cm². 2 The results described above are far inferior to those of Examples 1-5. Comparative Example 4 differs from Example 3 in that its silicon-to-hydrogen ratio is designed to be 1.22, resulting in very dense branched segments. Although the oil seepage area is smaller, the extrudability is too low to meet the requirements for high extrusion. Comparative Example 5 differs from Example 3 in that its silicon-to-hydrogen ratio is designed to be 4.45, resulting in overly loose branched segments. Although its extrusion rate is high, the overly loose branched structure weakens its anchoring effect on the powder, thus failing to achieve zero oil seepage. Selecting suitable modified vinyl silicone oil and modified side-hydrogen-containing silicone oil to form a branched structure and controlling a suitable silicon-to-hydrogen ratio are crucial for obtaining a single-component thermally conductive gel with high extrusion rate and zero oil seepage, avoiding the release and exudation of unreacted polymers.

[0150] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0151] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A one-component thermally conductive gel, characterized in that, It is prepared from raw materials comprising the following components, by weight: 100 parts of modified vinyl silicone oil, 20-60 parts of modified hydrogen-containing silicone oil. 2400-3200 parts of thermally conductive powder Inhibitor 0.01-0.2 parts, Platinum catalyst 2ppm-10ppm; The modified vinyl silicone oil is prepared by hydrosilylation reaction of terminal vinyl silicone oil and hydrogen-containing silane in the presence of a platinum catalyst. The hydrogen-containing silane is trimethoxysilane or triethoxysilane. The modified vinyl silicone oil has a viscosity of 10 mPa·s to 200 mPa·s and a vinyl content of 0.1 wt% to 1.5 wt%. The modified side-hydrogenated silicone oil is prepared by a hydrosilylation reaction of side-hydrogenated silicone oil and 1-olefins with 8-16 carbons in the presence of a platinum catalyst. The modified side-hydrogenated silicone oil has a hydrogen content of 0.05wt% to 0.3wt% and a viscosity of 50 to 500 mPa·s. The molar ratio of silanol groups in the modified hydrogen-containing silicone oil to vinyl groups in the modified vinyl silicone oil is 1.5 to 3.

0. The structural formula of the end-vinyl silicone oil is:

2. The single-component thermally conductive gel according to claim 1, characterized in that, The modified vinyl silicone oil has a viscosity of 50 mPa·s to 100 mPa·s and a vinyl content of 0.5 wt% to 1.0 wt%; and / or the modified hydrogen-containing silicone oil has a hydrogen content of 0.1 wt% to 0.2 wt% and a viscosity of 100 mPa·s to 300 mPa·s.

3. The single-component thermally conductive gel according to claim 1, characterized in that, The modified hydrogen-containing silicone oil prepared by means of the modified side-hydrogen silicone oil has a hydrogen content of 0.15wt% to 0.3wt% and a viscosity of 50 to 500 mPa·s. and / or During preparation, the molar ratio of the silanol group of the side-containing silicone oil to the vinyl group of the 1-olefin with 8-16 carbons is (3-5):

1.

4. The single-component thermally conductive gel according to claim 3, characterized in that, The hydrogen content of the hydrogen-containing silicone oil is 0.15wt% to 0.25wt%, and the viscosity is 100 to 300 mPa·s.

5. The single-component thermally conductive gel according to claim 1, characterized in that, The viscosity of the terminal vinyl silicone oil during the preparation of the modified vinyl silicone oil is 10 mPa·s to 200 mPa·s.

6. The single-component thermally conductive gel according to claim 5, characterized in that, The viscosity of the vinyl-terminated silicone oil is 50 mPa·s to 200 mPa·s, and the vinyl content is 0.6 wt% to 2.0 wt%.

7. The single-component thermally conductive gel according to any one of claims 1-6, characterized in that, The molar ratio of silane groups in the modified hydrogen-containing silicone oil to vinyl groups in the modified vinyl silicone oil is 2.0 to 3.

0.

8. The single-component thermally conductive gel according to any one of claims 1-6, characterized in that, When the modified vinyl silicone oil is 100 parts, the modified hydrogen-containing silicone oil is 30-55 parts, and the thermally conductive powder is 2600-3100 parts; and / or The inhibitor was administered at a dose of 0.1-0.2 parts; and / or The platinum catalyst concentration is 3 ppm to 8 ppm.

9. The single-component thermally conductive gel according to any one of claims 1-6, characterized in that, The thermally conductive powder is one or a combination of aluminum oxide, zinc oxide, magnesium oxide, aluminum nitride, and boron nitride.

10. The single-component thermally conductive gel according to any one of claims 1-6, characterized in that, The platinum catalyst is one or a combination of chloroplatinic acid, chloroplatinic acid-isopropanol complex, and cassette catalyst.

11. The single-component thermally conductive gel according to any one of claims 1-6, characterized in that, The inhibitor is one or a combination of 1-ethynyl-1-cyclohexanol, tetramethyltetravinylcyclotetrasiloxane, 2-methyl-3-butynyl-2-ol, 3-methyl-1-hexynyl-3-ol, 3,5-dimethyl-1-hexynyl-3-ol, and 3-methyl-1-dodecynyl-3-ol.

12. A method for preparing the single-component thermally conductive gel according to any one of claims 1-11, characterized in that, Includes the following steps: (1) The modified vinyl silicone oil and the modified hydrogen-containing silicone oil are put into a mixer and stirred and mixed evenly. Then the thermally conductive powder is added in batches. After the addition is completed, the temperature is raised to 70℃~90℃ and stirred and reacted for 1-3 hours to obtain the adhesive. The adhesive is then cooled to room temperature. (2) Add the inhibitor to a mixer and mix thoroughly; (3) Add the platinum catalyst, stir and mix evenly, and remove bubbles by vacuum to obtain a mixture; (4) The mixture obtained in step (3) is heated and pre-cured to obtain the single-component thermally conductive gel.

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