Single-component high-thermal-conductivity gel capable of resisting slippage and cracking and preparation method of single-component high-thermal-conductivity gel

Abstract

The invention provides a single-component high-thermal-conductivity gel capable of resisting slip cracking and a preparation method thereof, and relates to the technical field of thermal conductive adhesives. The single-component high-thermal-conductivity gel capable of resisting slippage and cracking is prepared from the following components in parts by weight: 60 to 90 parts of vinyl-terminated silicone oil, 5 to 15 parts of base rubber, 5 to 15 ppm of platinum catalyst, 0 to 10 parts of side hydrogen silicone oil, 10 to 20 parts of hydrogen-terminated silicone oil, 0.01 to 0.2 part of inhibitor and 1600 to 3500 parts of modified thermal conductive powder, the modified heat-conducting powder is prepared by the following steps: hydrolyzing vinyl silane, epoxy silane and tertiary amino silane to obtain a silane oligomer, carrying out condensation polymerization on the silane oligomer and hydroxyl on the surface of the heat-conducting powder to obtain an intermediate product, and carrying out free radical polymerization on the intermediate product and long-chain olefin. The single-component high-thermal-conductivity gel is prepared through surface treatment of the heat-conducting powder and matching of the base glue, and compared with existing heat-conducting gel, the single-component high-thermal-conductivity gel can effectively inhibit slippage and cracking phenomena under extreme environment conditions.

Description

Technical Field

[0001] This invention relates to the field of thermally conductive adhesives, and in particular to a single-component high thermal conductivity gel resistant to slip cracking and its preparation method. Background Technology

[0002] In recent years, with the continuous development and innovation of science and technology, industries such as electronic communications, intelligent robots, and new energy vehicles have experienced rapid growth. Most electronic components are moving towards miniaturization, precision, and increased power, leading to increasingly higher requirements for heat dissipation. If the heat generated by electronic components during operation cannot be dissipated in a timely manner, it will significantly impact their service life and lifespan. Currently, the main thermal conductive materials used in electronic components on the market include thermal conductive gel, thermal conductive pads, and thermal conductive grease. Thermal conductive gel, due to its excellent thermal conductivity, wide range of filling properties, and adaptability to automated dispensing, is widely used in industries such as 5G communications, consumer electronics, and new energy vehicles.

[0003] Thermal conductive gels can be divided into pre-cured one-component thermal conductive gels and two-component thermal conductive gels. Pre-cured one-component thermal conductive gels are similar to high-viscosity thermal grease, while two-component thermal conductive gels, after curing, resemble thermal pads. However, thermal pads are mainly used on smooth, flat surfaces, while two-component thermal conductive gels are suitable for various irregular surfaces. Especially in 5G communication and base station applications, most thermal conductive gels are used in vertically placed environments and face extreme conditions, such as the extreme cold of the Arctic and Antarctic, and the harsh weather of deserts, where the temperature difference between day and night can reach tens of degrees Celsius. Under such extreme temperature conditions, thermal conductive gels can experience severe slippage and cracking, significantly reducing their heat dissipation efficiency and shortening product lifespan.

[0004] Chinese patent document CN117720817 A discloses a single-component anti-cracking and anti-slip thermally conductive gel, its preparation method, and its application. It achieves anti-cracking and anti-slip properties through the synergistic effect of zirconium tungstate and raw rubber, avoiding the hardening and cracking caused by post-curing of pre-cured gels under long-term use at high temperatures. It can maintain a stable, flowing gel state in extreme environments for extended periods and can be repeatedly applied without damaging equipment. However, zirconium tungstate is difficult to synthesize, has high costs, and poor high-temperature performance, making its industrial application in the market challenging.

[0005] Slippage in thermally conductive gels is primarily due to insufficient adhesion between the gel and the contact surface under extreme conditions when used vertically, causing it to slowly slide off under gravity. Cracking, on the other hand, occurs when the thermally conductive material undergoes thermal expansion and contraction, and the powder treatment agent or silicone oil fails to effectively inhibit this expansion or contraction. Currently, high thermal conductivity gel materials on the market mainly consist of raw materials such as alumina, zinc oxide, aluminum hydroxide, aluminum nitride, and boron nitride. To address the industry's pain points and challenges, it is necessary to start with conventional materials. Summary of the Invention

[0006] This invention provides a single-component high thermal conductivity gel resistant to slip cracking and its preparation method, aiming to solve the above-mentioned problems existing in the background art.

[0007] To achieve the above objectives, embodiments of the present invention provide a single-component high thermal conductivity gel with anti-slip cracking and its preparation method. This involves surface modification of thermally conductive powder and the combination of a base adhesive. Specifically, small-molecule silanes are first hydrolyzed into oligomers, which then undergo a polycondensation reaction with the hydroxyl groups on the surface of the thermally conductive powder. The vinyl groups in the oligomers then undergo further free radical polymerization with long-chain olefins to prepare a modified thermally conductive powder with three encapsulation layers, thereby effectively inhibiting cracking. Simultaneously, the synergistic effect of the aluminum hydroxide sheet structure, the base adhesive, and the polar groups on the surface of the thermally conductive powder effectively improves slippage.

[0008] Embodiments of the present invention provide a single-component high thermal conductivity gel resistant to slip cracking, comprising the following components by weight:

[0009] 60-90 parts of vinyl-terminated silicone oil

[0010] 5-15 parts base adhesive

[0011] Platinum catalyst 5-15 ppm

[0012] Side-hydrogen silicone oil 0-10 parts

[0013] 10-20 parts of hydrogen-terminated silicone oil

[0014] Inhibitor 0.01-0.2 parts,

[0015] 1600-3500 parts of modified thermally conductive powder;

[0016] The preparation process of the modified thermally conductive powder is as follows: vinylsilane, epoxysilane, and tertiary aminosilane are hydrolyzed to obtain silane oligomers, which are then subjected to polycondensation reaction with hydroxyl groups on the surface of the thermally conductive powder to obtain intermediate products. These intermediate products are then subjected to free radical polymerization with long-chain olefins to obtain modified thermally conductive powder with three encapsulation layers.

[0017] Preferably, the preparation process of the modified thermally conductive powder specifically includes the following steps:

[0018] S1. Vinylsilane, epoxysilane, and tertiary aminosilane are added to a methanol solution, the pH is adjusted to 2-3 with dilute hydrochloric acid, the mixture is stirred at room temperature for 1-2 h, and then rotary evaporated at 100-120℃ to obtain silane oligomers; wherein the mass ratio of vinylsilane:epoxysilane:tertiary aminosilane:methanol is 10-30:10-30:10-30:10-60.

[0019] S2. Spray the above-mentioned silane oligomer onto the surface of the thermally conductive powder, heat to 100-120℃ and react for 0.5-2 hours to obtain an intermediate product; wherein the silane oligomer accounts for 0.1%-1% of the total mass of the thermally conductive powder;

[0020] S3. In a reaction vessel, solvent, long-chain olefin, and thermal initiator are added sequentially and stirred. Then, the above intermediate product is added, and the mixture is heated to 80-100℃ and reacted for 2-4 hours. After filtration, washing, and drying, modified thermally conductive powder is prepared. The mass ratio of long-chain olefin: thermally conductive powder: solvent is 0.1-0.5: 80-120: 80-120, and the thermal initiator accounts for 0.1wt.%-0.8wt.% of the long-chain olefin.

[0021] Preferably, the viscosity of the vinyl-terminated silicone oil is 50-1000 cp, and the vinyl content is 0.1 wt.%-2 wt.%. More preferably, the viscosity of the vinyl-terminated silicone oil is 100-500 cp, and the vinyl content is 0.1 wt.%-1 wt.%.

[0022] Preferably, the vinyl content in the base adhesive is 0.1 wt.% to 1 wt.%, and the silica content is 10 wt.% to 32 wt.%. More preferably, the vinyl content in the base adhesive is 0.2 wt.% to 1 wt.%, and the silica content is 20 wt.% to 32 wt.%.

[0023] Preferably, the hydrogen content of the side-hydrogen silicone oil is 0.01 wt.% to 0.4 wt.%, and the viscosity is 10 to 300 mPa·s. More preferably, the hydrogen content of the side-hydrogen silicone oil is 0.01 wt.% to 0.3 wt.%, and the viscosity is 50 to 200 mPa·s.

[0024] Preferably, the hydrogen content of the terminal hydrogen silicone oil is 0.007 wt.% to 0.3 wt.%, and the viscosity is 10 to 1000 mPa·s. More preferably, the hydrogen content of the terminal hydrogen silicone oil is 0.016 wt.% to 0.2 wt.%, and the viscosity is 30 to 500 mPa·s.

[0025] Preferably, the platinum catalyst is at least one of chloroplatinic acid, chloroplatinic acid-isopropanol complex, and chloroplatinic acid-divinyltetramethyldisiloxane complex.

[0026] Preferably, the inhibitor is at least one selected from 1-ethynyl-1-cyclohexanol, tetramethyltetravinylcyclotetrasiloxane, 2-methyl-3-butynyl-2-ol, 3-methyl-1-ethynyl-3-ol, 3,5-dimethyl-1-hexynyl-3-ol, and 3-methyl-1-dodecynyl-3-ol.

[0027] Preferably, the thermally conductive powder includes at least one of aluminum hydroxide, aluminum oxide, zinc oxide, aluminum nitride, boron nitride, and diamond.

[0028] More preferably, the thermally conductive powder is aluminum hydroxide and aluminum oxide.

[0029] More preferably, the alumina is spherical or near-spherical with a particle size of 1–100 μm; the aluminum hydroxide is plate-like with a particle size of 1–100 μm.

[0030] More preferably, the alumina is spherical with a particle size of 1-50 μm; and the aluminum hydroxide is plate-like with a particle size of 1-50 μm.

[0031] Based on a general inventive concept, embodiments of the present invention provide a method for preparing a slip-crack resistant single-component high thermal conductivity gel, the method comprising the following steps:

[0032] Step 1: Add the vinyl-terminated silicone oil and base adhesive to a planetary mixer and mix for 5-15 minutes until homogeneous. Then add the modified thermally conductive powder in batches, mixing for 10-30 minutes after each addition until homogeneous.

[0033] Step 2: Add inhibitor, side-hydrogen silicone oil, and terminal-hydrogen silicone oil and stir for 15-30 min. Then add platinum catalyst, stir under vacuum for 15-30 min, and heat to 80-100℃ to cure for 60-120 min to prepare the single-component high thermal conductivity gel.

[0034] This invention prepares a single-component high thermal conductivity gel by surface treatment of thermally conductive powder and combination with a base adhesive. Compared with existing thermally conductive gels, it has the following beneficial effects:

[0035] (1) Small molecule silane coupling agents are hydrolyzed to form oligomers, which then react with the hydroxyl groups on the surface of the thermally conductive powder. Since the silane oligomers have better encapsulation properties for the thermally conductive powder than small molecule silanes, they are grafted onto the surface of the thermally conductive powder to form the first layer of encapsulation. Then, the vinyl groups in the silane oligomers undergo free radical polymerization with the vinyl groups in the long-chain olefins to form the second layer of encapsulation on the surface of the thermally conductive powder. Furthermore, the long carbon chains in the long-chain olefins can entangle the thermally conductive powder to form the third layer of encapsulation. This three-layer encapsulation provides excellent protection against thermal expansion and contraction (i.e., cracking) of the thermally conductive gel under extreme conditions. At the same time, the presence of long-chain alkyl groups can improve extrusion performance.

[0036] (2) Since most aluminum hydroxides are irregular shapes such as sheet-like structures, they can increase the contact area with the substrate in the system, thereby increasing the friction force and reducing the slippage caused by gravity when placed vertically. Among them, spherical alumina is preferred, as it has a larger contact area with the substrate than spherical alumina.

[0037] (3) Furthermore, the macromolecular silicone oil in the base adhesive can effectively encapsulate and entangle the modified thermally conductive powder, thereby inhibiting cracking. Since the polar groups on the surface of the modified thermally conductive powder can form intermolecular forces with the hydroxyl groups of the silica in the base adhesive and the hydroxyl groups on the surface of the substrate, the bonding force between the thermally conductive gel and the surface of the substrate can be enhanced, which can effectively inhibit slippage and cracking to a certain extent. Detailed Implementation

[0038] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with specific embodiments.

[0039] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0040] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0041] Currently, most thermal conductive gels used in 5G communications and base stations are placed vertically and face extreme environments, such as the extreme cold of the Arctic and Antarctic, the harsh weather of deserts, and even the diurnal temperature range of tens of degrees Celsius in some areas. Under such extreme temperature conditions, thermal conductive gels may experience severe slippage and cracking, resulting in a significant decrease in heat conduction and heat dissipation, and a reduction in product lifespan.

[0042] Embodiments of the present invention provide a single-component high thermal conductivity gel resistant to slip cracking, comprising the following components by weight:

[0043] 60-90 parts of vinyl-terminated silicone oil

[0044] 5-15 parts base adhesive

[0045] Platinum catalyst 5-15 ppm

[0046] Side-hydrogen silicone oil 0-10 parts

[0047] 10-20 parts of hydrogen-terminated silicone oil

[0048] Inhibitor 0.01-0.2 parts,

[0049] 1600-3500 parts of modified thermally conductive powder;

[0050] The preparation process of the modified thermally conductive powder is as follows: vinylsilane, epoxysilane, and tertiary aminosilane are hydrolyzed to obtain silane oligomers, which are then subjected to polycondensation reaction with hydroxyl groups on the surface of the thermally conductive powder to obtain intermediate products. These intermediate products are then subjected to free radical polymerization with long-chain olefins to obtain modified thermally conductive powder with three encapsulation layers.

[0051] Preferably, the preparation process of the modified thermally conductive powder specifically includes the following steps:

[0052] S1. Vinylsilane, epoxysilane, and tertiary aminosilane are added to a methanol solution, the pH is adjusted to 2-3 with dilute hydrochloric acid, the mixture is stirred at room temperature for 1-2 h, and then rotary evaporated at 100-120℃ to obtain silane oligomers; wherein the mass ratio of vinylsilane:epoxysilane:tertiary aminosilane:methanol is 10-30:10-30:10-30:10-60.

[0053] S2. Spray the above-mentioned silane oligomer onto the surface of the thermally conductive powder, heat to 100-120℃ and react for 0.5-2 hours to obtain an intermediate product; wherein the silane oligomer accounts for 0.1%-1% of the total mass of the thermally conductive powder;

[0054] S3. In a reaction vessel, solvent, long-chain olefin, and thermal initiator are added sequentially and stirred. Then, the above intermediate product is added, and the mixture is heated to 80-100℃ and reacted for 2-4 hours. After filtration, washing, and drying, modified thermally conductive powder is prepared. The mass ratio of long-chain olefin: thermally conductive powder: solvent is 0.1-0.5: 80-120: 80-120, and the thermal initiator accounts for 0.1wt.%-0.8wt.% of the long-chain olefin.

[0055] Preferably, the viscosity of the vinyl-terminated silicone oil is 50-1000 cp, and the vinyl content is 0.1 wt.%-2 wt.%. More preferably, the viscosity of the vinyl-terminated silicone oil is 100-500 cp, and the vinyl content is 0.1 wt.%-1 wt.%.

[0056] Preferably, the vinyl content in the base adhesive is 0.1 wt.% to 1 wt.%, and the silica content is 10 wt.% to 32 wt.%. More preferably, the vinyl content in the base adhesive is 0.2 wt.% to 1 wt.%, and the silica content is 20 wt.% to 32 wt.%.

[0057] Preferably, the hydrogen content of the side-hydrogen silicone oil is 0.01 wt.% to 0.4 wt.%, and the viscosity is 10 to 300 mPa·s. More preferably, the hydrogen content of the side-hydrogen silicone oil is 0.01 wt.% to 0.3 wt.%, and the viscosity is 50 to 200 mPa·s.

[0058] Preferably, the hydrogen content of the terminal hydrogen silicone oil is 0.007 wt.% to 0.3 wt.%, and the viscosity is 10 to 1000 mPa·s. More preferably, the hydrogen content of the terminal hydrogen silicone oil is 0.016 wt.% to 0.2 wt.%, and the viscosity is 30 to 500 mPa·s.

[0059] Preferably, the platinum catalyst is at least one of chloroplatinic acid, chloroplatinic acid-isopropanol complex, and chloroplatinic acid-divinyltetramethyldisiloxane complex.

[0060] Preferably, the inhibitor is at least one selected from 1-ethynyl-1-cyclohexanol, tetramethyltetravinylcyclotetrasiloxane, 2-methyl-3-butynyl-2-ol, 3-methyl-1-ethynyl-3-ol, 3,5-dimethyl-1-hexynyl-3-ol, and 3-methyl-1-dodecynyl-3-ol.

[0061] Preferably, the thermally conductive powder includes at least one of aluminum hydroxide, aluminum oxide, zinc oxide, aluminum nitride, boron nitride, and diamond.

[0062] More preferably, the thermally conductive powder is aluminum hydroxide and aluminum oxide.

[0063] More preferably, the alumina is spherical or near-spherical with a particle size of 1–100 μm; the aluminum hydroxide is plate-like with a particle size of 1–100 μm.

[0064] More preferably, the alumina is spherical with a particle size of 1-50 μm; and the aluminum hydroxide is plate-like with a particle size of 1-50 μm.

[0065] Based on a general inventive concept, embodiments of the present invention provide a method for preparing a slip-crack resistant single-component high thermal conductivity gel, the method comprising the following steps:

[0066] Step 1: Add the vinyl-terminated silicone oil and base adhesive to a planetary mixer and mix for 5-15 minutes until homogeneous. Then add the modified thermally conductive powder in 3 batches, mixing for 10-30 minutes after each addition until homogeneous.

[0067] Step 2: Add inhibitor, side-hydrogen silicone oil, and terminal-hydrogen silicone oil and stir for 15-30 min. Then add platinum catalyst, stir under vacuum for 15-30 min, and heat to 80-100℃ to cure for 60-120 min to prepare the single-component high thermal conductivity gel.

[0068] The following is a detailed description through specific embodiments.

[0069] An embodiment of the present invention provides a method for preparing modified alumina, comprising the following steps:

[0070] (1) In a reaction vessel equipped with a stirrer and a dropping funnel, 20 parts of vinylsilane (vinyltriacetoxysilane), 20 parts of epoxysilane (KH560), and 10 parts of tertiary aminosilane (N,N-diethyl-3-aminopropyltrimethoxysilane) were added to 20 parts of methanol solution (methanol content 50%). The pH of the solution was adjusted to 2-3 with dilute hydrochloric acid and stirred at room temperature for 1 h. Subsequently, small molecules and by-products were removed by rotary evaporation to prepare silane oligomers.

[0071] (2) The above silane oligomer was sprayed onto the surface of alumina in a stirred tank and reacted for 1 hour. The mass ratio of silane oligomer to alumina was 0.5:100. The mixture was heated to 100°C for 1 hour to obtain an intermediate product.

[0072] (3) In a reaction vessel equipped with a stirrer, reflux condenser, dropping funnel and thermometer, add an appropriate amount of xylene, 1-hexadecene and thermal initiator (benzoyl peroxide BPO). The mass ratio of 1-hexadecene:alumina:xylene is 0.5:100:100. The thermal initiator (benzoyl peroxide BPO) accounts for about 0.5 wt.% of 1-hexadecene. Then add the above intermediate product, heat to 80°C and react for 3 hours. After filtration, washing and drying, the modified alumina is obtained.

[0073] Embodiments of the present invention also provide a method for preparing modified aluminum hydroxide, comprising the following steps:

[0074] (1) In a reaction vessel equipped with a stirrer and a dropping funnel, 20 parts of vinylsilane (vinyltriacetoxysilane), 20 parts of epoxysilane (KH560), and 10 parts of tertiary aminosilane (N,N-diethyl-3-aminopropyltrimethoxysilane) were added to 20 parts of methanol solution (methanol content 50%). The pH of the solution was adjusted to 2-3 with dilute hydrochloric acid and stirred at room temperature for 1 h. Subsequently, small molecules and by-products were removed by rotary evaporation to prepare silane oligomers.

[0075] (2) The above silane oligomer was sprayed onto the surface of aluminum hydroxide in a stirred tank and reacted for 1 hour. The mass ratio of silane oligomer to aluminum hydroxide was 0.5:100. The mixture was heated to 100°C for 1 hour to obtain an intermediate product.

[0076] (3) In a reaction vessel equipped with a stirrer, reflux condenser, dropping funnel and thermometer, add an appropriate amount of xylene, 1-hexadecene and thermal initiator (benzoyl peroxide BPO). The mass ratio of 1-hexadecene:aluminum hydroxide:xylene is 0.5:100:100. The thermal initiator (benzoyl peroxide BPO) accounts for about 0.5 wt.% of 1-hexadecene. Then add the above intermediate product, heat to 80°C and react for 3 hours. After filtration, washing and drying, the modified aluminum hydroxide is obtained.

[0077] The modified alumina and modified aluminum hydroxide described above were used in all the following examples.

[0078] Example 1

[0079] This embodiment provides a single-component high thermal conductivity gel that resists slip cracking, comprising the following components by weight:

[0080]

[0081] The preparation method of the above-mentioned anti-slip cracking single-component high thermal conductivity gel includes the following steps:

[0082] (1) Add the vinyl-terminated silicone oil and base glue into a planetary mixer and mix for 5-15 minutes until they are evenly mixed. Then add the modified thermally conductive powder in 3 equal batches. After each addition, mix for 10-30 minutes until the system is evenly mixed.

[0083] (2) After adding inhibitor, side hydrogen silicone oil and terminal hydrogen silicone oil and stirring for 15-30 min, add platinum catalyst and continue vacuum stirring for 15-30 min. Then heat to 80-100℃ and solidify for 60-120 min to prepare the single-component high thermal conductivity gel.

[0084] Example 2

[0085] This embodiment provides a single-component high thermal conductivity gel that resists slip cracking, comprising the following components by weight:

[0086]

[0087] The preparation method of the above-mentioned anti-slip cracking single-component high thermal conductivity gel includes the following steps:

[0088] (1) Add the vinyl-terminated silicone oil and base glue into a planetary mixer and mix for 5-15 minutes until they are evenly mixed. Then add the modified thermally conductive powder in 3 equal batches. After each addition, mix for 10-30 minutes until the system is evenly mixed.

[0089] (2) After adding inhibitor, side hydrogen silicone oil and terminal hydrogen silicone oil and stirring for 15-30 min, add platinum catalyst and continue vacuum stirring for 15-30 min. Then heat to 80-100℃ and solidify for 60-120 min to prepare the single-component high thermal conductivity gel.

[0090] Example 3

[0091] This embodiment provides a single-component high thermal conductivity gel that resists slip cracking, comprising the following components by weight:

[0092]

[0093] The preparation method of the above-mentioned anti-slip cracking single-component high thermal conductivity gel includes the following steps:

[0094] (1) Add the vinyl-terminated silicone oil and base glue into a planetary mixer and mix for 5-15 minutes until they are evenly mixed. Then add the modified thermally conductive powder in 3 equal batches. After each addition, mix for 10-30 minutes until the system is evenly mixed.

[0095] (2) After adding inhibitor, side hydrogen silicone oil and terminal hydrogen silicone oil and stirring for 15-30 min, add platinum catalyst and continue vacuum stirring for 15-30 min. Then heat to 80-100℃ and solidify for 60-120 min to prepare the single-component high thermal conductivity gel.

[0096] Example 4

[0097] This embodiment provides a single-component high thermal conductivity gel that resists slip cracking, comprising the following components by weight:

[0098]

[0099] The preparation method of the above-mentioned anti-slip cracking single-component high thermal conductivity gel includes the following steps:

[0100] (1) Add the vinyl-terminated silicone oil and base glue into a planetary mixer and mix for 5-15 minutes until they are evenly mixed. Then add the modified thermally conductive powder in 3 equal batches. After each addition, mix for 10-30 minutes until the system is evenly mixed.

[0101] (2) After adding inhibitor, side hydrogen silicone oil and terminal hydrogen silicone oil and stirring for 15-30 min, add platinum catalyst and continue vacuum stirring for 15-30 min. Then heat to 80-100℃ and solidify for 60-120 min to prepare the single-component high thermal conductivity gel.

[0102] Example 5

[0103] This embodiment provides a single-component high thermal conductivity gel that resists slip cracking, comprising the following components by weight:

[0104]

[0105] The preparation method of the above-mentioned anti-slip cracking single-component high thermal conductivity gel includes the following steps:

[0106] (1) Add the vinyl-terminated silicone oil and base glue into a planetary mixer and mix for 5-15 minutes until they are evenly mixed. Then add the modified thermally conductive powder in 3 equal batches. After each addition, mix for 10-30 minutes until the system is evenly mixed.

[0107] (2) After adding inhibitor, side hydrogen silicone oil and terminal hydrogen silicone oil and stirring for 15-30 min, add platinum catalyst and continue vacuum stirring for 15-30 min. Then heat to 80-100℃ and solidify for 60-120 min to prepare the single-component high thermal conductivity gel.

[0108] This comparative example provides a method for preparing hexadecyltrimethoxysilane-modified alumina, comprising the following steps: spraying hexadecyltrimethoxysilane onto the surface of alumina in a stirred tank and reacting for 2 hours, wherein the mass ratio of hexadecyltrimethoxysilane to alumina is 0.5:100, heating to 80°C for 2 hours, to obtain hexadecyltrimethoxysilane-modified alumina.

[0109] This comparative example provides a method for preparing hexadecyltrimethoxysilane-modified aluminum hydroxide, comprising the following steps: spraying hexadecyltrimethoxysilane onto the surface of aluminum hydroxide in a stirred tank and reacting for 2 hours, wherein the mass ratio of hexadecyltrimethoxysilane to aluminum hydroxide is 0.5:100, heating to 80°C for 2 hours, to obtain hexadecyltrimethoxysilane-modified aluminum hydroxide.

[0110] The following comparative examples all use the above-mentioned hexadecyltrimethoxysilane-modified alumina and hexadecyltrimethoxysilane-modified aluminum hydroxide.

[0111] Comparative Example 1

[0112] This comparative example provides a single-component high thermal conductivity gel, which comprises the following components by weight:

[0113]

[0114] The preparation method of the above-mentioned single-component high thermal conductivity gel includes the following steps:

[0115] (1) Add vinyl-terminated silicone oil into a planetary mixer, and then add hexadecyltrimethoxysilane-modified alumina and hexadecyltrimethoxysilane-modified aluminum hydroxide in three equal batches. Stir for 10-30 min after each addition until the system is evenly mixed.

[0116] (2) After adding inhibitor, side hydrogen silicone oil and terminal hydrogen silicone oil and stirring for 15-30 min, add platinum catalyst and continue vacuum stirring for 15-30 min. Then heat to 80-100℃ and solidify for 60-120 min to prepare the single-component high thermal conductivity gel.

[0117] Comparative Example 2

[0118] This comparative example provides a single-component high thermal conductivity gel, which comprises the following components by weight:

[0119]

[0120] The preparation method of the above-mentioned single-component high thermal conductivity gel includes the following steps:

[0121] (1) Add vinyl-terminated silicone oil into a planetary mixer, and then add hexadecyltrimethoxysilane-modified alumina and hexadecyltrimethoxysilane-modified aluminum hydroxide in three equal batches. Stir for 10-30 min after each addition until the system is evenly mixed.

[0122] (2) After adding inhibitor, side hydrogen silicone oil and terminal hydrogen silicone oil and stirring for 15-30 min, add platinum catalyst and continue vacuum stirring for 15-30 min. Then heat to 80-100℃ and solidify for 60-120 min to prepare the single-component high thermal conductivity gel.

[0123] Comparative Example 3

[0124] This comparative example provides a single-component high thermal conductivity gel, which comprises the following components by weight:

[0125]

[0126] The preparation method of the above-mentioned single-component high thermal conductivity gel includes the following steps:

[0127] (1) Add the vinyl-terminated silicone oil and base glue into a planetary mixer and mix for 5-15 minutes until they are evenly mixed. Then add hexadecyltrimethoxysilane-modified alumina and hexadecyltrimethoxysilane-modified aluminum hydroxide in three equal batches. After each addition, stir for 10-30 minutes until the system is evenly mixed.

[0128] (2) After adding inhibitor, side hydrogen silicone oil and terminal hydrogen silicone oil and stirring for 15-30 min, add platinum catalyst and continue vacuum stirring for 15-30 min. Then heat to 80-100℃ and solidify for 60-120 min to prepare the single-component high thermal conductivity gel.

[0129] Comparative Example 4

[0130] This comparative example provides a single-component high thermal conductivity gel, which comprises the following components by weight:

[0131]

[0132] The preparation method of the above-mentioned single-component high thermal conductivity gel includes the following steps:

[0133] (1) Add the vinyl-terminated silicone oil and base glue into a planetary mixer and mix for 5-15 minutes until they are evenly mixed. Then add hexadecyltrimethoxysilane-modified alumina and hexadecyltrimethoxysilane-modified aluminum hydroxide in three equal batches. After each addition, stir for 10-30 minutes until the system is evenly mixed.

[0134] (2) After adding inhibitor, side hydrogen silicone oil and terminal hydrogen silicone oil and stirring for 15-30 min, add platinum catalyst and continue vacuum stirring for 15-30 min. Then heat to 80-100℃ and solidify for 60-120 min to prepare the single-component high thermal conductivity gel.

[0135] Comparative Example 5

[0136] This comparative example provides a single-component high thermal conductivity gel, which comprises the following components by weight:

[0137]

[0138] The preparation method of the above-mentioned single-component high thermal conductivity gel includes the following steps:

[0139] (1) Add vinyl-terminated silicone oil into a planetary mixer, and then add silane oligomer modified thermal conductive powder in three equal batches. Stir for 10-30 minutes after each addition until the system is evenly mixed.

[0140] (2) After adding inhibitor, side hydrogen silicone oil and terminal hydrogen silicone oil and stirring for 15-30 min, add platinum catalyst and continue vacuum stirring for 15-30 min. Then heat to 80-100℃ and solidify for 60-120 min to prepare the single-component high thermal conductivity gel.

[0141] The thermally conductive gels prepared in Examples 1 to 5 and Comparative Examples 1 to 5 were subjected to performance testing, specifically including the following steps:

[0142] Equal amounts of the thermally conductive gels prepared in Examples 1-5 and Comparative Examples 1-5 were placed between an aluminum fixture with a surface roughness of 3.0 ± 0.2 μm and a glass plate, with a thickness limited to 2 mm. The fixtures were vertically inserted into a base and placed in a high-temperature oven at 125°C, an 85% RH oven at 85°C, and a thermal shock chamber at -40°C to 125°C for 1000 hours. The temperature was maintained at -40°C for 25 minutes, then increased to 125°C in 5 minutes, decreased to -40°C in 15 minutes, and maintained at 125°C for 25 minutes. Each cycle lasted 1 hour, and 1000 cycles were performed. The samples were observed for slippage and cracking.

[0143] In the slip test, "0, +, ++, +++" represent no slip, slight slip, moderate slip, and severe slip, respectively.

[0144] In the cracking test, "0, +, ++, +++" represent no cracking, slight cracking, moderate cracking, and severe cracking, respectively.

[0145] The test results are shown in Table 1 below:

[0146] Table 1

[0147]

[0148] As can be seen from Table 1 above, when the base adhesive was used in combination with modified aluminum hydroxide and modified aluminum oxide in Examples 1 to 5, no slippage or cracking was found under various aging conditions for 1000 hours.

[0149] In Comparative Examples 1 and 2, the thermally conductive gels made of alumina and aluminum hydroxide modified with common long-chain alkylsilanes exhibited severe slippage and cracking under various conditions. However, in Comparative Example 2, the presence of aluminum hydroxide increased the contact area with the contact material interface, resulting in improved slippage compared to Comparative Example 1.

[0150] Comparative Examples 3 and 4 used a base adhesive, which showed improvement in slip cracking. This is because the base adhesive contains more macromolecular long-chain silicone oil, which is much better at encapsulating and wrapping the thermally conductive powder than low-viscosity vinyl silicone oil.

[0151] In Comparative Example 5, the modified thermally conductive alumina and aluminum hydroxide prepared in the above examples alone showed a significant improvement in slip and cracking under all aging conditions.

[0152] Based on Examples 1 to 5 and Comparative Examples 1 to 5, it can be seen that, from the perspective of modified thermally conductive powder, the surface forms a multi-layered effective coating during the modification process, which can effectively suppress thermal expansion and contraction, thereby greatly improving cracking. The coating layer is a macromolecule formed by free radical polymerization of silane oligomers, which has much better temperature resistance than ordinary long-chain alkyl hexadecyltrimethoxysilanes. At the same time, the polar groups on the powder surface can form corresponding intermolecular forces with the silica in the base adhesive and the hydroxyl groups on the substrate contact surface, improving the adhesion of the thermally conductive gel to the substrate surface in a vertical condition. Meanwhile, the high-viscosity macromolecular silicone oil in the base adhesive can also reduce the cracking of the thermally conductive gel to a certain extent by coating the thermally conductive powder. Modified aluminum hydroxide, due to its surface morphology being mainly sheet-like, can increase the base area for contact with the substrate, thereby improving adhesion and reducing slippage. Through the coordinated effect of various aspects, the slippage and cracking of single-component thermally conductive gels can be improved to a limited extent.

[0153] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A single component high thermal conductivity gel against slippage cracking, characterized by, According to the weight parts, the following components are included: vinyl-terminated silicone oil 60-90 parts, base glue 5-15 parts, platinum catalyst 5-15 ppm, side hydrogen silicone oil 0-10 parts, hydrogen-terminated silicone oil 10-20 parts, inhibitor 0.01-0.2 parts, modified heat-conducting powder 1600-3500 parts. The preparation process of the modified heat-conducting powder: hydrolyze vinyl silane, epoxy silane and tertiary amino silane to obtain silane oligomers, then perform polycondensation reaction with the hydroxyl groups on the surface of the heat-conducting powder to obtain an intermediate product, and then perform free radical polymerization with long-chain olefins to obtain the modified heat-conducting powder with three layers of wrapping.

2. The single component high thermal conductivity gel against slippage cracking according to claim 1, characterized in that, The preparation process of the modified heat-conducting powder specifically includes the following steps: S1, add vinyl silane, epoxy silane and tertiary amino silane to a methanol solution, adjust the pH to 2-3 by dilute hydrochloric acid, stir and mix at room temperature for 1-2 hours, and rotary evaporate at 100-120°C to obtain silane oligomers; wherein the mass ratio of vinyl silane: epoxy silane: tertiary amino silane: methanol is 10-30: 10-30: 10-30: 10-60; S2, spray the above silane oligomers onto the surface of the heat-conducting powder, heat to 100-120°C and react for 0.5-2 hours to obtain an intermediate product; wherein the silane oligomers account for 0.1%-1% of the total mass of the heat-conducting powder; S3, add solvent, long-chain olefins and thermal initiator into a reaction kettle in sequence, stir and mix, then add the above intermediate product, heat to 80-100°C and react for 2-4 hours, and then filter, wash and dry to obtain the modified heat-conducting powder: wherein the mass ratio of long-chain olefins: heat-conducting powder: solvent is 0.1-0.5: 80-120: 80-120, and the thermal initiator accounts for 0.1wt.%-0.8wt.% of the long-chain olefins.

3. The single component high thermal conductivity gel against slippage cracking according to claim 1, characterized in that, The viscosity of the vinyl-terminated silicone oil is 50-1000 cp, and the content of vinyl is 0.1wt.%-2wt.%.

4. The single component high thermal conductivity gel against slippage cracking according to claim 1, characterized in that, The content of vinyl in the base glue is 0.1wt.%-1wt.% and the content of white carbon black is 10wt.%-32wt.%.

5. The single component high thermal conductivity gel against slippage cracking according to claim 1, characterized in that, The hydrogen content of the side hydrogen silicone oil is 0.01wt.%-0.4wt.% and the viscosity is 10-300 mPa·s; the hydrogen content of the hydrogen-terminated silicone oil is 0.007wt.%-0.3wt.% and the viscosity is 10-1000 mPa·s.

6. The single component high thermal conductivity gel against slippage cracking according to claim 1, characterized in that, The platinum catalyst is at least one of chloroplatinic acid, chloroplatinic acid-isopropyl alcohol complex and chloroplatinic acid-divinyltetramethyldisiloxane complex.

7. The single component high thermal conductivity gel against slippage cracking according to claim 1, characterized in that, The inhibitor is at least one of 1-ethynyl-1-cyclohexanol, tetramethyltetraethenylcyclotetrasiloxane, 2-methyl-3-butynyl-2-alcohol, 3-methyl-1-ethynyl-3-alcohol, 3,5-dimethyl-1-hexynyl-3-alcohol and 3-methyl-1-dodecyn-3-alcohol.

8. The single component high thermal conductivity gel against slippage cracking according to claim 1, characterized in that, The heat-conducting powder includes at least one of aluminum hydroxide, aluminum oxide, zinc oxide, aluminum nitride, boron nitride and diamond.

9. The single component high thermal conductivity gel against slippage cracking according to claim 8, characterized in that, The aluminum oxide is spherical, and the particle size is 1-100 um; the aluminum hydroxide has a flaky structure, and the particle size is 1-100 um.

10. A process for the preparation of a single component high thermal conductivity gel against slippage cracking, characterized by, The preparation method of the single-component high-thermal-conductivity gel comprises the following steps: First step: put end-vinyl silicone oil and base glue into a planetary mixer, stir for 5-15 min to mix uniformly, then put modified thermal-conductivity powder into the mixer in batches, stir for 10-30 min after each batch, and repeat until the mixture is uniform; Second step: add inhibitor, side-hydrogen silicone oil and end-hydrogen silicone oil, stir for 15-30 min, then add platinum catalyst, stir for 15-30 min under vacuum, heat to 80-100 DEG C, and solidify for 60-120 min to obtain the single-component high-thermal-conductivity gel.

Images