Single-component heat-conducting wave-absorbing gel as well as preparation method and application thereof

Abstract

The invention relates to single-component heat-conducting and wave-absorbing gel as well as a preparation method and application thereof, and belongs to the technical field of heat-conducting and wave-absorbing gel. The single-component heat-conducting wave-absorbing gel comprises liquid silicone oil, methyl vinyl raw rubber, hydroxyl silicone oil, a mixed modified filler, a curing agent and a catalyst, wherein the liquid silicone oil comprises at least one of vinyl silicone oil or phenyl vinyl silicone oil; the mixed modified filler comprises a modified heat-conducting filler and a modified wave-absorbing filler. Through synergistic cooperation of the liquid silicone oil, the mixed modified filler, the methyl vinyl raw rubber and the hydroxyl silicone oil, the product simultaneously has high thermal conductivity and wave-absorbing characteristic, has a moisture and heating dual-curing mode, can control seepage of the silicone oil, has good bonding strength, can well connect an interface between a radiator and a heat source, and has good thermal conductivity and wave-absorbing property. Therefore, the method can be effectively applied to electronic components.

Description

Technical Field

[0001] The present application relates to the technical field of heat-conducting and wave-absorbing composite materials, and in particular to a single-component heat-conducting and wave-absorbing gel and a preparation method and application thereof. Background Art

[0002] As electronic devices develop towards high power consumption, miniaturization and integration, heat dissipation and electromagnetic interference (EMI) problems are becoming increasingly serious. Traditional heat dissipation materials such as thermal grease and heat sinks have limitations and cannot solve both heat dissipation and EMI problems at the same time. Thermal grease needs to be replaced regularly and is prone to oil seepage, affecting device stability; heat sinks are limited by structure and materials and are difficult to meet complex heat dissipation requirements. Traditional EMI suppression materials may increase device complexity and cost and are incompatible with heat dissipation requirements.

[0003] To meet these challenges, single-component thermally conductive and absorbing gels have emerged, which can effectively reduce contact thermal resistance, improve heat dissipation efficiency, and suppress EMI to a certain extent, providing dual protection of heat dissipation and electromagnetic shielding. However, existing single-component thermally conductive and absorbing gels are usually cured in the form of micro-crosslinking. Although they can solve the problems of oil seepage and silicon precipitation in the gel to a certain extent, they will still seep oil when used under long-term high temperature conditions, and the bonding performance is poor. Summary of the invention

[0004] To solve the above problems, the purpose of the embodiments of the present application includes providing a one-component thermally conductive and absorbing gel and a preparation method and application thereof. The silicone oil precipitation of the one-component thermally conductive and absorbing gel is controllable and has excellent bonding properties.

[0005] In a first aspect, the present application provides a one-component thermally conductive and wave-absorbing gel, comprising liquid silicone oil, methyl vinyl rubber, hydroxy silicone oil, a mixed modified filler, a curing agent and a catalyst; wherein the liquid silicone oil comprises at least one of vinyl silicone oil or phenyl vinyl silicone oil; and the mixed modified filler comprises a modified thermally conductive filler and a modified wave-absorbing filler.

[0006] In the above technical scheme, the mixed modified filler is evenly dispersed in the liquid resin matrix and has good compatibility with the resin through the synergistic combination of methyl vinyl rubber, liquid silicone oil, hydroxy silicone oil and mixed modified filler, so that the single-component thermal conductive wave absorbing gel has high thermal conductivity and wave absorbing properties. At the same time, the introduction of methyl vinyl rubber can reduce the exudation of silicone oil, and can be double cured to have good bonding strength. On the one hand, methyl vinyl rubber has a large weight average molecular weight. After being introduced into the system and combined with liquid silicone oil, it can improve the strength of the product after curing and ensure the efficient filling and combination of the mixed modified filler at the same time. In addition, the longer molecular chain can well lock the small molecular branched silicone oil and reduce the precipitation of silicone oil. On the other hand, methyl vinyl rubber and liquid silicone oil are cured by heating to accelerate curing or curing at room temperature for a long time, while hydroxy silicone oil reacts with water vapor in the air to perform moisture curing. The double curing method combined with the addition of methyl vinyl rubber makes the product have good bonding strength.

[0007] In some embodiments of the present application, the single-component thermally conductive and absorbing gel includes the following components in parts by weight: 85-135 parts of liquid silicone oil, 8-15 parts of methyl vinyl rubber, 15-25 parts of hydroxy silicone oil, 800-1350 parts of modified thermally conductive filler, 250-500 parts of modified absorbing filler, 5-10 parts of curing agent, 0.1-0.5 parts of inhibitor, 1-4 parts of platinum water catalyst, and 1-2 parts of organic tin catalyst.

[0008] In the above technical solution, liquid silicone oil and methyl vinyl rubber can be cured by heating or prolonged curing at room temperature under the action of curing agent and platinum water catalyst, while hydroxy silicone oil can be cured by moisture under the action of organic tin catalyst. By controlling the specific ratio of each component, thermal conductivity and wave absorption can be effectively improved, bonding strength can be enhanced and silicone oil exudation can be reduced.

[0009] In some embodiments of the present application, the ratio of vinyl silicone oil to phenyl vinyl silicone oil in liquid silicone oil is (60-125):(10-30). The viscosity of vinyl silicone oil is 100-500 mPa.s, and the viscosity of phenyl vinyl silicone oil is 8000-10000 mPa.s.

[0010] In the above technical solution, vinyl silicone oil has good powder filling properties but poor temperature resistance, while phenyl vinyl silicone oil is the opposite. By controlling the dosage and viscosity of the two, the filling amount of the mixed modified filler and the temperature resistance of the final product can be effectively regulated.

[0011] In some embodiments of the present application, the modified thermally conductive filler is a thermally conductive filler treated with a silane coupling agent, and the modified absorbing filler is a absorbing filler treated with a silane coupling agent;

[0012] Optionally, the thermally conductive filler includes at least one of aluminum oxide, aluminum nitride, diamond or boron nitride, and the particle size of the thermally conductive filler is 0.1-120 μm;

[0013] Optionally, the wave absorbing filler includes at least one of carbonyl iron powder, iron silicon aluminum, tin oxide or tin pyrophosphate;

[0014] Optionally, the silane coupling agent includes at least one of vinyl terminated silane or alkyl alkoxy silane.

[0015] In the above technical solution, by performing surface coating modification on the thermal conductive filler and the wave absorbing filler, the compatibility between the filler and the silicone oil can be effectively enhanced, thereby increasing the effective filling amount of the powder and enhancing the thermal conductivity and wave absorbing properties.

[0016] In some embodiments of the present application, the weight average molecular weight of the methyl vinyl rubber is 500,000-700,000.

[0017] In the above technical solution, the methyl vinyl rubber has a suitable weight average molecular weight, which can effectively improve the overall strength of the product, control the leakage of silicone oil, and does not affect the effective filling of the powder filler.

[0018] In a second aspect, the present invention provides a method for preparing a single-component thermally conductive and wave-absorbing gel, comprising the following steps:

[0019] Powder surface modification: spraying silane coupling agent solution onto the surface of mixed thermal conductive filler and wave absorbing filler under vacuum heating and stirring conditions to obtain mixed modified filler;

[0020] Pretreatment of liquid resin matrix: liquid silicone oil and methyl vinyl rubber are heated and stirred in vacuum, and then hydroxy silicone oil is added, and stirred and mixed under nitrogen protection to obtain a liquid resin matrix;

[0021] Gel preparation: Mix the mixed modified filler, liquid resin matrix, inhibitor, curing agent and catalyst to obtain a single-component thermal conductive and wave absorbing gel.

[0022] In the above technical scheme, by pre-treating the liquid resin matrix with vacuum heating, small siloxane molecules can be effectively removed, and the methyl vinyl rubber can be used to further reduce the leakage of silicone oil and prevent the liquid resin from cross-linking and curing in advance. Spraying silane coupling agent on the surface of thermal conductive fillers and wave absorbing fillers can make the surface of powder fillers uniformly coated and modified, which can enhance the compatibility between powder and resin, improve the uniformity of the dispersion of fillers in the liquid resin matrix, and thus improve the thermal conductivity and wave absorbing properties.

[0023] In some embodiments of the present application, in the powder surface modification step, the vacuum heating and stirring conditions include: temperature of 80-100° C., time of 0.5-2 h.

[0024] In the above technical solution, spraying the modified solution under heating and stirring conditions can achieve surface coating modification more uniformly and fully.

[0025] In some embodiments of the present application, in the liquid resin matrix pretreatment step, the vacuum heating, stirring and mixing conditions include: a temperature of 80-150° C. and a time of 0.5-2 h.

[0026] In the above technical solution, continuous stirring at high temperature can better disperse the methyl vinyl rubber and the vinyl silicone oil, while removing small siloxane molecules.

[0027] In some embodiments of the present application, in the gel preparation step, the mixing conditions include: stirring at below 30° C. for 0.5-1.5 h under nitrogen protection.

[0028] In the above technical solution, the air can be completely isolated under nitrogen protection and low temperature conditions to prevent the liquid silicone oil and hydroxy silicone oil from solidifying prematurely.

[0029] In a third aspect, the present application also provides the application of the above-mentioned single-component thermally conductive and wave-absorbing gel in electronic components.

[0030] The single-component thermally conductive and wave-absorbing gel provided in the embodiment of the present application has high thermal conductivity and wave-absorbing properties, and also has curable bonding properties and reliable bonding strength, so it can be effectively used in WIFI6, home appliances, automotive electronics, smart wearables, optical modules, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 This is a process flow chart of a method for preparing a single-component thermally conductive and microwave-absorbing gel provided in an embodiment of the present application. DETAILED DESCRIPTION

[0033] Figure 1 This is a process flow chart of the preparation method of the single-component thermally conductive and wave-absorbing gel provided in the embodiment of the present application. Figure 1 The method for preparing the single-component thermally conductive and wave-absorbing gel provided in the present application comprises the following steps:

[0034] S110, powder surface modification: spraying a silane coupling agent solution onto the surface of the mixed thermal conductive filler and wave absorbing filler under vacuum heating and stirring conditions to obtain a mixed modified filler.

[0035] The usage ratio of the thermal conductive filler and the wave absorbing filler can be (800-1350):(250-500).

[0036] The thermally conductive filler may include at least one of aluminum oxide, aluminum nitride, diamond, and boron nitride, and the particle size of the thermally conductive filler is 0.1-120 μm. Preferably, by selecting thermally conductive powders of various particle sizes and types, the thermally conductive network structure can be adjusted to further improve the thermal conductivity. As an example, the thermally conductive filler may include spherical aluminum oxide with a particle size of 10 μm, spherical aluminum nitride with a particle size of 120 μm, and single crystal diamond with a particle size of 40 μm.

[0037] The wave absorbing filler may include at least one of spherical carbonyl iron powder, flake iron-silicon-aluminum, snow-petal-shaped tin oxide and tin pyrophosphate.

[0038] The silane coupling agent may include at least one of vinyl terminated silane or alkyl alkoxy silane. As an example, the silane coupling agent may be vinyl trimethoxy silane, vinyl triethoxy silane, methyl methoxy silane, methyl triethoxy silane, and the like.

[0039] It is understandable that other coupling agents with reactive groups or other excellent grafting effects with a thermal decomposition temperature above 200° C. can also be used. The coupling agent has a high thermal decomposition temperature, has excellent stability at high temperatures after coating and modification, and can also reduce the impact of volatilization.

[0040] The silane coupling agent solution can be prepared by diluting the silane coupling agent with ethanol. The mass ratio of the silane coupling agent to the ethanol can be 1:5. The amount of the silane coupling agent can be 3.5wt% of the total weight of the mixed powder.

[0041] The temperature of vacuum heating and stirring treatment can be 80-100° C., the time can be 0.5-2 h, and the stirring speed can be 800 rpm / min. As an example, the temperature of vacuum heating and stirring is 80° C., and the time is 1 h.

[0042] It can be understood that in the embodiment of the present application, the weight added after the silane coupling agent coating modification can be ignored. The weight of the modified thermal conductive filler can be regarded as equal to the weight of the thermal conductive filler, and the weight of the modified absorbing filler can be regarded as equal to the weight of the absorbing filler.

[0043] S120, pretreatment of liquid resin matrix: vacuum heating and stirring the liquid silicone oil and methyl vinyl rubber, adding hydroxy silicone oil, stirring and mixing under nitrogen protection, to obtain a liquid resin matrix.

[0044] Among them, the weight ratio of methyl vinyl rubber, liquid silicone oil and hydroxy silicone oil can be (8-15):(90-135):(15-25).

[0045] The liquid silicone oil may include at least one of vinyl silicone oil and phenyl vinyl silicone oil. Preferably, the liquid silicone oil is vinyl silicone oil and phenyl vinyl silicone oil, wherein the viscosity of the vinyl silicone oil is 100-500 mPa.s, and the viscosity of the phenyl vinyl silicone resin is 8000-10000 mPa.s. The usage ratio of the vinyl silicone oil and the phenyl vinyl silicone resin is (60-125):(10-30).

[0046] The weight average molecular weight of the methyl vinyl raw rubber is greater than 500,000. Preferably, the weight average molecular weight of the methyl vinyl raw rubber is 500,000-700,000.

[0047] It should be noted that the hydroxy silicone oil in the embodiments of the present application refers to polydimethylsiloxane terminated with silanol groups, and the viscosity of the hydroxy silicone oil may be 350 mPa.s.

[0048] The specific mixing method can be: heat the methyl vinyl raw rubber and phenyl vinyl silicone oil and stir them centrifugally, then add the vinyl silicone oil, stir and mix them under vacuum conditions at 80-150°C for 0.5-2h, finally add the hydroxy silicone oil, pass nitrogen protection, and continue stirring for 0.5-1.5h to obtain a treated liquid resin matrix.

[0049] Optionally, vinyl silicone oil can be used in a variety of different viscosities, such as 100mPa.s and 500mPa.s. The viscosity corresponds to the weight average molecular weight and the length of the molecular chain. By compounding vinyl silicone oils of different viscosities with methyl vinyl rubber and hydroxy silicone oils of corresponding viscosities, the final strength of the product can be controlled and the filling property of the mixed modified filler can be optimized.

[0050] S130, gel preparation: mixing the mixed modified filler, the liquid resin matrix, the inhibitor, the curing agent, the first catalyst, and the second catalyst to obtain a single-component thermal conductive and wave absorbing gel.

[0051] The mixing is carried out under nitrogen protection, the temperature is below 30° C., and the stirring is performed for 0.5-1.5 h.

[0052] The usage ratio of the mixed modified filler, the liquid resin matrix, the inhibitor, the curing agent, the first catalyst and the second catalyst can be (1300-1850): (115-175): (0.1-0.5): (5-10): (1-4): (1-2).

[0053] The inhibitor may be ethynyl cyclohexanol, the curing agent may be hydrogen-containing silicone oil, the first catalyst may be a platinum water catalyst with a platinum activity of 5000 ppm, and the second catalyst may be an organic tin compound.

[0054] In actual production, the preparation method further includes canning the single-component thermal conductive and microwave absorbing gel. Specifically, the steps include: under nitrogen protection, using professional gel canning equipment to pack the gel into EFD single-component syringes of different specifications, such as 10cc, 30cc, 300cc, etc.

[0055] The embodiment of the present application also provides a single-component thermal conductive and wave absorbing gel prepared by the above-mentioned preparation method, comprising the following components in parts by weight: 85-135 parts of liquid silicone oil, 8-15 parts of methyl vinyl rubber, 15-25 parts of hydroxy silicone oil, 1300-1850 parts of mixed modified filler, 5-10 parts of curing agent, 0.1-0.5 parts of inhibitor, and 1-5 parts of catalyst.

[0056] The liquid silicone oil includes at least one of vinyl silicone oil and phenyl vinyl silicone oil, the mixed modified filler includes a modified thermal conductive filler and a modified wave absorbing filler, and the catalyst includes a platinum water catalyst and an organic tin catalyst.

[0057] By adding methyl vinyl rubber, vinyl silicone oil and hydroxy silicone oil into the system and using modified thermal conductive fillers and modified absorbing fillers, the prepared single-component absorbing gel has excellent thermal conductivity and absorbing properties, can control the leakage of silicone oil, and has good bonding properties, which can well connect the interface between the radiator and the heat source.

[0058] The embodiment of the present application also provides an application of the above-mentioned single-component thermal conductive wave absorbing gel in electronic products. Among them, the electronic products can be WIFI6, home appliances, automotive electronics, smart wearables, optical modules, etc.

[0059] The single-component thermally conductive and absorbing gel has both high thermal conductivity and wave absorption, which can solve the problems of heat conduction and electromagnetic interference at the same time. The product is in the form of gel and is easy to plasticize. It can be used in low stress, large assembly tolerance and scenes. It can be used with a dispensing machine for automated application as a solution for unmanned workshops. In addition, the product has a dual curing method of moisture and heating, which can control the seepage of silicone oil. It also has good bonding properties and can well connect the interface between the radiator and the heat source. Therefore, it can be effectively used in various electronic components.

[0060] When in use, the single-component thermal conductive and absorbing gel can be dispensed on the chip or heat sink with the cooperation of air pressure or screw dispensing machine, and placed at room temperature for 8-12 hours. After the surface reacts with moisture in the air to undergo moisture curing, it is further placed in a 60-90°C oven and continued to be baked for 2-4 hours to obtain the best curing and bonding properties.

[0061] Among them, leaving it at room temperature allows the hydroxy silicone oil to be moisture-cured first, increasing the bonding strength with the interface. In this process, the liquid silicone oil and methyl vinyl rubber slowly cure. By further heating and baking, the curing is accelerated and the reaction is more complete, thereby improving the bonding strength.

[0062] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0063] The sources of some of the raw materials used in the examples and comparative examples of the present application are shown in Table 1 below.

[0064] Table 1 Sources of some raw materials in the examples and comparative examples

[0065]

[0066]

[0067] Example 1

[0068] This embodiment provides a single-component thermally conductive and microwave-absorbing gel, and a preparation method thereof comprises the following steps:

[0069] (1) Powder surface modification: 80g of spherical alumina with a particle size of 10μm, 100g of single-crystal alumina with a particle size of 0.6μm, 700g of spherical aluminum nitride with a particle size of 120μm, 200g of spherical aluminum nitride with a particle size of 2μm, 150g of single-crystal diamond with a particle size of 40μm, and 325g of flaky carbonyl iron powder, 10g of snowflake-shaped tin oxide and tin pyrophosphate compound powder, were placed in a stirred reactor, the fine powder agglomeration phenomenon was broken up, and the powder was pre-dispersed. Vinyl-terminated silane was diluted with alcohol at a mass ratio of 1:5, and the amount of vinyl-terminated silane was 3.5wt% of the total weight of the mixed powder. Under stirring conditions, the vinyl-terminated silane solution was sprayed on the surface of the mixed powder, and the stirring speed was increased to 800rpm / min during the stirring and dispersion process, and vacuum heating treatment was performed at a temperature of 80°C and a modification time of 1h to obtain a mixed modified filler.

[0070] (2) Pretreatment of liquid resin matrix: 10 g of methyl vinyl rubber with a weight average molecular weight of 500,000 and 20 g of phenyl vinyl silicone oil with a viscosity of 10,000 mPa.s were centrifugally stirred at a high temperature of 150°C. After the solid methyl vinyl rubber was completely fused with the liquid phenyl vinyl silicone oil, 70 g of vinyl silicone oil with a viscosity of 100 mPa.s and 10 g of vinyl silicone oil with a viscosity of 500 mPa.s were added successively. The mixture was treated at 150°C in a vacuum state for 30 min. Finally, 15 g of hydroxy silicone oil with a viscosity of 350 mPa.s was added. Nitrogen protection was introduced and the treatment was continued for 1 h. The treated liquid resin matrix was obtained by cooling.

[0071] (3) Gel preparation: Add the mixed modified filler to the liquid resin matrix, mix and stir in a stirring tank, add 0.1g of ethynyl cyclohexanol inhibitor and 5g of hydrogenated silicone oil curing agent, 1.5g of platinum water catalyst with a platinum activity of 5000ppm, and 1g of organic tin compound in sequence, keep nitrogen protection during stirring, and pass cooling water through the stirring barrel to ensure that the temperature of the stirring tank is below 30°C, stir for 1 hour, and obtain the final glue. The stirred glue is filled into EFD single-component syringes of different specifications, such as 10cc, 30cc, 300cc, etc., through professional gel canning equipment under nitrogen protection to obtain a single-component thermal conductive and wave absorbing gel.

[0072] The preparation methods of Examples 2-6 are substantially the same as those of Example 1, the only difference being the specific raw materials and the amounts used, as shown in Table 2.

[0073] Table 2 Amount of raw materials used in Examples 1-6 (unit: g)

[0074]

[0075]

[0076] Comparative Example 1

[0077] This comparative example provides a single-component heat-conducting and wave-absorbing gel, and its preparation method is substantially the same as that of Example 1, except that: in step (2), methyl vinyl rubber is not added.

[0078] Step (2) comprises: 30 g of phenyl vinyl silicone oil with a viscosity of 10000 mPa.s, 70 g of vinyl silicone oil with a viscosity of 100 mPa.s and 10 g of vinyl silicone oil with a viscosity of 500 mPa.s are vacuumed and continuously heated at 150°C for 30 min, and finally 15 g of hydroxy silicone oil with a viscosity of 350 mPa.s is added, nitrogen protection is introduced, the treatment is continued for 1 h, and cooling is performed to obtain a treated liquid resin matrix.

[0079] Comparative Example 2

[0080] This comparative example provides a single-component thermally conductive and wave-absorbing gel, and its preparation method is substantially the same as that of Example 1, except that: hydroxy silicone oil is not added in step (2).

[0081] Step (2) comprises: centrifugally stirring 10 g of methyl vinyl rubber with a weight average molecular weight of 500,000 and 25 g of phenyl vinyl silicone oil with a viscosity of 10,000 MPa.s at a high temperature of 150°C, and after the solid rubber is completely compatible with the silicone oil to form a liquid, successively adding 75 g of vinyl silicone oil with a viscosity of 100 MPa.s and 15 g of vinyl silicone oil with a viscosity of 500 MPa.s, and evacuating and continuously heating at 150°C for 30 minutes.

[0082] Comparative Example 3

[0083] This comparative example provides a single-component thermally conductive and microwave-absorbing gel, and its preparation method is substantially the same as that of Example 1, except that in step (1), the thermally conductive filler and the microwave-absorbing filler are not subjected to surface modification treatment.

[0084] Step (1) comprises: putting 80 g of spherical alumina with a particle size of 10 μm, 100 g of single-crystal alumina with a particle size of 0.6 μm, 700 g of spherical aluminum nitride with a particle size of 120 μm, 200 g of spherical aluminum nitride with a particle size of 2 μm, 150 g of single-crystal diamond with a particle size of 40 μm, and 325 g of flaky carbonyl iron powder, and 10 g of snowflake-shaped tin oxide and tin pyrophosphate compound powder into a stirred reactor, stirring and mixing at 80° C. for 1 hour to obtain a mixed filler.

[0085] Performance testing and results

[0086] The single-component thermally conductive and absorbing gel samples prepared in the examples and comparative examples were dispensed on the chip using a dispensing machine, left at room temperature for 12 hours, and after the surface moisture solidified, further placed in a 75°C oven and continued to bake for 2.5 hours to obtain a thermally conductive and absorbing sheet. The thermally conductive and absorbing sheet was subjected to performance testing, and the specific testing method was as follows:

[0087] (1) Thermal conductivity: The thermal conductivity of the thermally conductive and absorbing sheet is tested according to ASTM D 5470;

[0088] (2) Hardness: The hardness of the thermal conductive and absorbing sheet is tested according to ASTM D 2240 standard;

[0089] (3) Reflection loss: According to the GJB2038A-2011 test standard, the reflection loss of the thermal conductive and absorbing sheet is tested using the bow reflection method;

[0090] (4) Oil-diameter ratio: Place a heat-conducting and absorbing sheet with a diameter of 30 mm on filter paper, cover it with filter paper, compress it by 50%, put it in an oven at 125°C for 72 hours, and measure the longest diffusion distance A of the heat-conducting and absorbing sheet on the filter paper. Oil-diameter ratio = A / 30*100%;

[0091] (5) Bond strength: Tested in accordance with GB / T 7124-2008 test standard.

[0092] The above performance test results are shown in Table 3.

[0093] Table 3 Properties of heat-conducting and wave-absorbing sheets in Examples and Comparative Examples

[0094]

[0095]

[0096] As can be seen from Table 3, the single-component thermally conductive and absorbing gels prepared in Examples 1-6 of the present application all have excellent thermal conductivity and absorbing properties, as well as excellent bonding properties, and also have suitable hardness and a low oil-diameter ratio, which can meet the requirement that the thermal conductivity is not less than 3.5w / mk, the reflection loss at 25Ghz can be as low as -49Db / mm, the Shore C hardness can be maintained at a suitable 40-60, the oil-diameter ratio is not higher than 105%, and the bonding strength is greater than 0.5Mpa.

[0097] By comparing the performance test results of Example 1 and Comparative Examples 1-3, it can be seen that in Comparative Example 1, no methyl vinyl rubber is added, and the bonding strength after gel curing is significantly reduced, and the oil-diameter ratio is increased. In Comparative Example 2, no hydroxy silicone oil is added, resulting in only one cross-linking curing mode in the system, and the bonding strength is significantly reduced. In Comparative Example 3, no surface modification is performed on the thermal conductive filler and the wave absorbing filler, resulting in poor compatibility and poor dispersibility between the filler and the liquid resin, resulting in a significant reduction in both thermal conductivity and wave absorbing performance, and an increase in the oil-diameter ratio and a serious decrease in bonding performance.

[0098] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

Claims

1. A single-component thermally conductive and microwave-absorbing gel, characterized in that: It includes liquid silicone oil, methyl vinyl rubber, hydroxy silicone oil, mixed modified filler, curing agent and catalyst; wherein the liquid silicone oil includes at least one of vinyl silicone oil or phenyl vinyl silicone oil; the mixed modified filler includes modified thermal conductive filler and modified wave absorbing filler.

2. The single-component thermally conductive and wave-absorbing gel according to claim 1, characterized in that: The composition comprises the following components in parts by weight: 85-135 parts of liquid silicone oil, 8-15 parts of methyl vinyl rubber, 15-25 parts of hydroxy silicone oil, 800-1350 parts of modified thermal conductive filler, 250-500 parts of modified absorbing filler, 5-10 parts of curing agent, 0.1-0.5 parts of inhibitor, 1-4 parts of platinum water catalyst, and 1-2 parts of organic tin catalyst.

3. The single-component thermally conductive and wave-absorbing gel according to any one of claims 1 to 2, characterized in that: The ratio of the amount of vinyl silicone oil to the amount of phenyl vinyl silicone oil in the liquid silicone oil is (60-125):(10-30); The viscosity of the vinyl silicone oil is 100-500 mPa.s, and the viscosity of the phenyl vinyl silicone oil is 8000-10000 mPa.s.

4. The single-component thermally conductive and wave-absorbing gel according to any one of claims 1 to 2, characterized in that: The modified thermally conductive filler is a thermally conductive filler treated with a silane coupling agent, and the modified wave-absorbing filler is a wave-absorbing filler treated with a silane coupling agent; Optionally, the thermally conductive filler includes at least one of aluminum oxide, aluminum nitride, diamond or boron nitride, and the particle size of the thermally conductive filler is 0.1-120 μm; Optionally, the wave absorbing filler includes at least one of carbonyl iron powder, iron silicon aluminum, tin oxide or tin pyrophosphate; Optionally, the silane coupling agent includes at least one of vinyl terminated silane or alkyl alkoxy silane.

5. The single-component thermally conductive and wave-absorbing gel according to any one of claims 1 to 2, characterized in that: The weight average molecular weight of the methyl vinyl raw rubber is 500,000-700,000.

6. A method for preparing the single-component thermally conductive and wave-absorbing gel according to any one of claims 1 to 5, characterized in that: The following steps are involved: Powder surface modification: spraying a silane coupling agent solution onto the surface of the mixed thermal conductive filler and wave absorbing filler under vacuum heating and stirring conditions to obtain the mixed modified filler; Pretreatment of the liquid resin matrix: the liquid silicone oil and the methyl vinyl rubber are heated and stirred in a vacuum, and then the hydroxy silicone oil is added, and the mixture is stirred and mixed under nitrogen protection to obtain a liquid resin matrix; Gel preparation: The mixed modified filler, liquid resin matrix, inhibitor, curing agent and catalyst are mixed to obtain a single-component heat-conducting and wave-absorbing gel.

7. The preparation method according to claim 6, characterized in that: In the powder surface modification step, the vacuum heating and stirring conditions include: temperature of 80-100° C. and time of 0.5-2 h.

8. The preparation method according to claim 6, characterized in that: In the liquid resin matrix pretreatment step, the vacuum heating, stirring and mixing conditions include: a temperature of 80-150° C. and a time of 0.5-2 h.

9. The preparation method according to claim 6, characterized in that: In the gel preparation step, the mixing conditions include: stirring at below 30° C. for 0.5-1.5 h under nitrogen protection.

10. Use of the single-component thermally conductive and microwave-absorbing gel according to any one of claims 1 to 5 in electronic components.

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