Highly heat-conductive metal-based radiation heat dissipation coating and preparation method thereof

Abstract

The application belongs to the technical field of functional protective coating materials, and particularly relates to a high-thermal-conductivity metal-based radiation heat dissipation coating and a preparation method thereof. The high-thermal-conductivity metal-based radiation heat dissipation coating is prepared from raw materials including a thermal conductive filler, an epoxy resin, a curing agent and a dispersing agent. The thermal conductive filler includes one or more of carbon-based materials, nitrides and carbides. The coating has a thermal conductivity of more than 30 W / (m*K), an atmospheric window infrared emissivity of more than 95% at 100 DEG C, and excellent impact resistance, wear resistance, acid and alkali oil aging resistance, and is suitable for efficient heat dissipation of metal-based heat sources such as motors, engines and photovoltaic back plates.

Description

Technical Field

[0001] This invention belongs to the technical field of functional protective coating materials, specifically relating to a high thermal conductivity metal-based radiation heat dissipation coating and its preparation method. Background Technology

[0002] With the rapid development of cutting-edge technologies such as 5G communication, new energy vehicles, high-power LEDs, and aerospace, electronic devices and power equipment are rapidly evolving towards miniaturization, integration, and high power density, with heat flux density per unit area exceeding 100W / cm². 2 The heat generated inside the equipment increases significantly, making heat dissipation efficiency a key factor limiting equipment performance and lifespan. Studies show that for every 2°C increase in temperature, equipment durability decreases by 10%, and its service life is significantly shortened.

[0003] Traditional heat dissipation methods such as fins, heat pipes, and fans are difficult to meet the heat dissipation requirements of miniaturized devices due to their large size, heavy weight, high energy consumption, and noise issues. Coating heat dissipation technology has become a research hotspot for next-generation high-efficiency thermal management solutions due to its simple process, conformal shape, and lack of additional space and weight. However, current heat dissipation coatings rely on silicone thermal conductive gels or alumina gels, which can improve heat dissipation efficiency to some extent, but their thermal conductivity is still below 10 W / (m·K), and these thermal conductive coatings also have certain problems such as poor wear resistance and aging performance.

[0004] The thermal conductivity of the resin matrix in general coatings is relatively low due to the characteristics of its polymer structure (less than 0.4 W / (m·K)). Therefore, thermally conductive powders are usually added to increase its thermal conductivity. At the same time, the polymer resin matrix usually has a high emissivity in the atmospheric window, which can realize the heat dissipation path from heat conduction to heat radiation. However, the difficulty in realizing this heat dissipation path lies in the selection of the type, morphology and particle size of the thermally conductive filler, as well as the need to optimize the resin and filler of the coating to ensure that it has both high thermal conductivity and high emissivity, while also taking into account the physical properties of the coating itself, such as aging resistance and wear resistance.

[0005] Therefore, there is an urgent need to provide a high thermal conductivity metal-based radiation heat dissipation coating that has a high thermal conductivity coefficient, a high emissivity (greater than 95%) in the 6-10µm atmospheric window at 100℃, and also takes into account the coating's wear resistance, aging resistance and other properties. Summary of the Invention

[0006] The purpose of this invention is to provide a high thermal conductivity metal-based radiation heat dissipation coating that, while having a high thermal conductivity coefficient, also has a high emissivity (greater than 95%) in the 6-10µm atmospheric window at 100℃, and at the same time takes into account the coating's wear resistance, aging resistance and other properties.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] The first aspect of the present invention provides a high thermal conductivity metal-based radiation heat dissipation coating, the raw materials for which include thermally conductive fillers, epoxy resin, curing agent, and dispersant.

[0009] Preferably, the mass ratio of the thermally conductive filler to the epoxy resin is 1:(1-2).

[0010] Preferably, the mass ratio of the thermally conductive filler to the dispersant is (1-3):1.

[0011] Preferably, the amount of curing agent added is 45%-55% of the mass of epoxy resin.

[0012] Preferably, the thermally conductive filler accounts for 20%-30% of the system, and the dispersant accounts for 15%-20% of the system.

[0013] Preferably, the thermally conductive filler includes one or more of carbon-based materials, nitrides, and carbides.

[0014] Preferably, the thermally conductive filler has one or more morphologies, such as sheet, tubular, or spherical.

[0015] Preferably, the particle size of the nitride and carbide is 1-5 μm.

[0016] Preferably, the carbon-based material is a multi-walled material, i.e., a multi-walled carbon nanotube; more preferably, it is a carboxylated multi-walled carbon nanotube.

[0017] The multi-walled carbon nanotubes and carboxylated multi-walled carbon nanotubes have an inner diameter of 3-5 nm, an outer diameter of 8-15 nm, and a tube length of 8-15 μm.

[0018] In some preferred embodiments, the carboxylated multi-walled carbon nanotubes can be added in the form of a dispersion, such as a carboxylated carbon nanotube butyl acetate dispersion; the solid content of the carboxylated carbon nanotube butyl acetate dispersion is 2wt%, the inner diameter of the carbon nanotubes is 3-5nm, the outer diameter is 8-15nm, and the tube length is 10-30μm.

[0019] Preferably, the nitride is BN.

[0020] Preferably, the BN includes one or both of cubic BN and hexagonal BN.

[0021] Preferably, the carbide comprises SiC.

[0022] In some preferred embodiments, the thermally conductive filler comprises a carbon-based material, a nitride, and a carbide; the mass ratio of the carbon-based material, the nitride, and the carbide is 1:(6-8):(8-13), wherein the carbon-based material is carboxylated carbon nanotubes, and the nitride can be cubic phase BN or a mixture of cubic phase BN and hexagonal phase BN, with a mass ratio of 1:(2-3).

[0023] By multi-scale composites of carbon-based materials (carbon nanotubes), two-dimensional biomaterials (BN), and particulate SiC, a three-dimensional continuous thermally conductive network can be formed in epoxy resin, thereby significantly reducing the interfacial thermal resistance between fillers. This is because one-dimensional CNTs provide long-range thermal conduction channels, two-dimensional BN sheets provide in-plane high thermal conductivity paths and act as bridges, and particulate SiC fills the gaps between fibers and sheets. The three components interlock to form a three-dimensional framework from points to lines to surfaces, greatly improving the phonon transport efficiency within the coating, thus achieving thermal conductivity far superior to traditional single-filler systems.

[0024] Preferably, the epoxy resin has an epoxy equivalent of 210-240 g / eq and a softening point of 14-23℃.

[0025] Preferably, the epoxy resin E44 is purchased from Jiangsu Sanmu Chemical Co., Ltd.

[0026] By combining high thermal conductivity fillers with high infrared emissivity fillers into an epoxy resin matrix, excellent infrared emissivity can be maintained while ensuring high thermal conductivity. This is because epoxy resin itself has a high intrinsic emissivity in the atmospheric window, while the added fillers such as SiC and BN also have high emissivity in the mid-infrared region. At the same time, the high thermal conductivity fillers (such as carbon nanotubes) construct a continuous thermally conductive network, enabling heat from the matrix to be rapidly conducted to the coating surface, and the surface heat is then radiated into the environment through high emissivity, thus achieving a synergistic heat dissipation pathway of rapid conduction and efficient radiation.

[0027] By loading an appropriate proportion of composite thermally conductive fillers into epoxy resin, the coating maintains good spray / self-leveling workability, high impact resistance, low wear, and excellent aging resistance. This is because the surface of carboxylated carbon nanotubes has active groups that can chemically bond with epoxy resin, enhancing the filler-resin interface bonding force; simultaneously, one-dimensional and two-dimensional fillers can inhibit crack propagation and absorb impact energy during curing; and epoxy resin itself has excellent corrosion resistance and mechanical strength, thus maintaining the overall mechanical stability and durability of the coating even with a high filler content.

[0028] Preferably, the curing agent is one of polyamide 650, polyamide 651, polyamide 5140, and polyetheramine D230.

[0029] Preferably, the dispersant is one or more of isopropanol, methyl methyl ethyl ketone, methyl isobutyl ketone, xylene, and n-butanol.

[0030] In some preferred embodiments, the dispersant comprises xylene and n-butanol in a mass ratio of 1:(2-3).

[0031] A second aspect of the present invention provides a method for preparing the aforementioned high thermal conductivity metal-based radiation heat dissipation coating, comprising the following steps:

[0032] S1. Preparation of dispersion: Add the dispersion to the reaction vessel and stir at 800 rpm for 8-12 min to obtain the dispersion;

[0033] S2. Preparation of thermally conductive filler dispersion solution: Add the thermally conductive filler to the dispersion solution and stir at 1500 rpm for 3-4 hours to prepare the thermally conductive filler dispersion solution;

[0034] S3. Preparation of epoxy resin thermal conductive coating: Add epoxy resin to the thermal conductive filler dispersion, stir at 1500 rpm for 0.5-1.5 h, and then sonicate for 25-35 min to obtain epoxy resin thermal conductive coating.

[0035] S4. Preparation of high thermal conductivity and radiation heat dissipation coating: After stirring and mixing the epoxy resin thermally conductive coating and the curing agent at a speed of 500 rpm for 10-20 min, the mixture is applied to the surface of the substrate and dried to obtain a high thermal conductivity and radiation heat dissipation coating.

[0036] Preferably, in step S3, the specific conditions for ultrasound are: ultrasound frequency of 40kHz, ultrasound power of 110-130W, and ultrasound temperature of 23-25℃.

[0037] Preferably, in step S4, the coating method includes either self-leveling or spraying.

[0038] Preferably, in step S4, the specific drying steps are as follows: drying in an oven at 75-85℃ for 25-35 minutes, and then heating to 115-125℃ and drying for 25-35 minutes.

[0039] The working principle of the high thermal conductivity metal-based radiation heat dissipation coating prepared by this invention is described in [reference needed]. Figure 1 .from Figure 1 It can be seen that the heat Q of the matrix S The working heat Q generated from inside the substrate (such as motors, engines, etc.) T After coating the substrate surface with a thermally conductive and radiative heat dissipation coating, the heat Q of the substrate is reduced. S Heat will accumulate at the interface between the two materials, where the coating will dissipate the heat Q at the interface through good adhesion with the substrate. S-CThe heat is conducted to the heat dissipation coating, and the heat Q inside the coating is transferred by adding a filler with high thermal conductivity. C The heat is conducted to the coating surface, and finally, the high emissivity of the coating surface is used to dissipate the heat Q. C-A It radiates into the atmosphere, thereby achieving the purpose of heat dissipation and cooling of the substrate.

[0040] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows:

[0041] 1. This invention proposes a high thermal conductivity metal-based radiation heat dissipation coating, whose thermal conductivity is much higher than that of traditional materials, reaching more than 30 W / (m·K), and whose infrared emissivity can reach more than 95% at 100℃, exhibiting excellent thermal conductivity and thermal radiation performance.

[0042] 2. The high thermal conductivity metal-based radiation heat dissipation coating prepared by this invention has excellent physical properties, including good wear resistance, aging resistance, acid and alkali resistance, salt spray resistance, high hardness, and excellent impact resistance.

[0043] 3. The high thermal conductivity metal-based radiation heat dissipation coating prepared by this invention has a wide range of applications. It can be applied to various heat sources, especially metal-based ones, such as heat sinks for engines and motors, photovoltaic backsheets, etc. The coating can be sprayed, self-leveled, or impregnated, with diverse coating methods and controllable viscosity. Attached Figure Description

[0044] Figure 1 The working principle of the high thermal conductivity metal-based radiation heat dissipation coating prepared by this invention is shown in the figure: Q S -The heat of the matrix, Q T -Working heat, Q S-C -Heat at the interface, Q C -Heat inside the coating, Q C-A Heat on the coating surface.

[0045] Figure 2 The infrared emissivity test value is from Embodiment 1 of the present invention.

[0046] Figure 3 The infrared emissivity test value of Embodiment 1 of the present invention at 100°C.

[0047] Figure 4 This is a physical image of the bending test of Embodiment 1 of the present invention.

[0048] Figure 5 This is a photograph of the actual product used in the impact resistance test of the coating in Embodiment 1 of the present invention.

[0049] Figure 6 This is a photograph of the actual product used in the wear resistance test of the coating in Embodiment 1 of the present invention.

[0050] Figure 7 This is a photograph of the actual product used in the test of the coating's resistance to acid, alkali, and oil aging in Example 1 of the present invention. Detailed Implementation

[0051] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] All raw materials used in this invention are commercially available, as detailed below:

[0053] Carbon nanotubes, purity > 98wt%, inner diameter 3-5nm, outer diameter 8-15nm, length 10-30μm, Suzhou Andy Nanotechnology Co., Ltd.

[0054] Carboxylated carbon nanotubes, purity > 98wt%, carboxyl content 3.86wt%, inner diameter 3-5nm, outer diameter 8-15nm, length 8-15μm, Suzhou Andy Nanotechnology Co., Ltd.

[0055] Cubic BN, particle size 2μm, purity >99.9%, MCC New Materials Technology Co., Ltd.

[0056] Hexagonal BN, particle size 1μm, purity >98.5%, Suzhou Napu Materials Technology Co., Ltd.

[0057] TiO2, rutile type, particle size 0.5μm, purity >99.95%, China Metallurgical Research Institute.

[0058] Ag powder, particle size 2μm, purity >99.99%, Shanghai Maclean Biochemical Technology Co., Ltd.

[0059] SiC, particle size 1μm or 5μm, α phase, purity >98%, Zhengzhou Haixu Abrasive Co., Ltd.

[0060] AlN, particle size 5μm, N content >32.5%, Shanghai Maclean Biochemical Technology Co., Ltd.

[0061] Modified CNTs@SiO2, Shaanxi Longlin Nanofiber Materials Technology Co., Ltd.

[0062] Carboxylated carbon nanotube butyl acetate dispersion, wherein the carboxylated carbon nanotubes have a diameter of 5-15 nm, a length of 10-30 μm, and a solid content of 2 wt%, manufactured by Chengdu Jiacai Technology Co., Ltd.

[0063] Epoxy resin E44, epoxy equivalent 210-240g / eq, volatile matter ≤0.6%, softening point 14-23℃, Jiangsu Sanmu Chemical Co., Ltd.

[0064] Epoxy resin E51, epoxy equivalent 184-200g / eq, volatile matter ≤0.3%, viscosity at 25℃ 10-18Pa·s, Jiangsu Sanmu Chemical Co., Ltd.

[0065] Polyamide 650, amine value 180-220 mg KOH / g, viscosity at 75℃ 6-12 Pa·s, Chuzhou Huisheng Electronic Materials Co., Ltd.

[0066] Polyamide 651, amine value 280-320mg KOH / g, viscosity at 25℃ 2000-3000mPa·s, Chuzhou Huisheng Electronic Materials Co., Ltd.

[0067] Polyamide 5140, amine value 370-400mg KOH / g, viscosity at 25℃ 8000-12000mPa·s, Shenzhen Jiadida New Material Technology Co., Ltd.

[0068] Polyetheramine D230, amine value 5.6-6.2 mmol / g, viscosity at 25℃ 9-13 mPa·s, Chuzhou Huisheng Electronic Materials Co., Ltd.

[0069] Example 1:

[0070] This embodiment provides a high thermal conductivity metal-based radiation heat dissipation coating, the raw materials for which, by weight, are 18 parts of thermally conductive filler, 23 parts of epoxy resin, 11.5 parts of curing agent, and 10 parts of dispersant.

[0071] The mass ratio of the thermally conductive filler to the epoxy resin is 18:23.

[0072] The ratio of the thermally conductive filler to the dispersant is 1.8:1.

[0073] The amount of curing agent added is 50% of the mass of epoxy resin.

[0074] The thermally conductive filler accounts for 28.8% of the system, and the dispersant accounts for 16% of the system.

[0075] The thermally conductive filler is composed of carbon-based materials, nitrides, and carbides in a mass ratio of 1:7:10.

[0076] The carbon-based material is a carboxylated carbon nanotube.

[0077] The nitride is BN.

[0078] The BN is cubic phase BN with a particle size of 2 μm.

[0079] The carbide is SiC with a particle size of 1 μm.

[0080] The epoxy resin has an epoxy equivalent of 210-240 g / eq and a softening point of 14-23℃.

[0081] The epoxy resin is epoxy resin E44.

[0082] The curing agent is polyamide 651.

[0083] The dispersant is xylene and n-butanol in a mass ratio of 3:7.

[0084] The preparation method of the high thermal conductivity radiation heat dissipation coating includes the following steps:

[0085] S1. Preparation of dispersion: Add the dispersion to the reaction vessel and mix and stir at 800 rpm for 10 min to obtain the dispersion;

[0086] S2. Preparation of thermally conductive filler dispersion solution: Add the thermally conductive filler to the dispersion solution and stir at 1500 rpm for 3.5 h to prepare the thermally conductive filler dispersion solution;

[0087] S3. Preparation of epoxy resin thermal conductive coating: Epoxy resin is added to the thermal conductive filler dispersion, stirred at 1500 rpm for 1 hour, and then sonicated for 30 minutes to obtain epoxy resin thermal conductive coating.

[0088] S4. Preparation of high thermal conductivity radiation heat dissipation coating: After stirring and mixing the epoxy resin thermally conductive coating and the curing agent at a speed of 500 rpm for 15 min, the mixture is applied to the surface of the substrate and dried to obtain a high thermal conductivity radiation heat dissipation coating with a dry film thickness of 50 μm.

[0089] In step S3, the specific conditions for ultrasound are: ultrasound frequency of 40kHz, ultrasound power of 120W, and ultrasound temperature of 25℃.

[0090] In step S4, the coating method is spraying.

[0091] In step S4, the specific steps of drying are as follows: drying in an 80°C oven for 30 minutes, and then heating to 120°C and drying for 30 minutes.

[0092] Example 2:

[0093] This embodiment provides a high thermal conductivity metal-based radiation heat dissipation coating, and the specific implementation method is the same as that in Embodiment 1, except that:

[0094] The BN is a mixture of cubic BN and hexagonal BN in a mass ratio of 2:5.

[0095] Example 3:

[0096] This embodiment provides a high thermal conductivity metal-based radiation heat dissipation coating. The specific implementation method is the same as that in Embodiment 1, except that the raw materials for its preparation, by weight, are 12.8 parts of thermally conductive filler, 23 parts of epoxy resin, 11.5 parts of curing agent, and 10 parts of dispersant.

[0097] The mass ratio of the thermally conductive filler to the epoxy resin is 64:115.

[0098] The mass ratio of the thermally conductive filler to the dispersant is 1.28:1.

[0099] The amount of curing agent added is 50% of the mass of epoxy resin.

[0100] The thermally conductive filler accounts for 22.34% of the system, and the dispersant accounts for 17.45% of the system.

[0101] The thermally conductive filler is composed of carbon-based material, nitride, and carbide; the mass ratio of the carbon-based material, nitride, and carbide is 0.8:5:7, wherein the carbon-based material is carboxylated carbon nanotubes, added in the form of a dispersion, the solid content of the carboxylated carbon nanotube butyl acetate dispersion is 2wt%, the inner diameter of the carbon nanotubes is 3-5nm, the outer diameter is 8-15nm, and the tube length is 10-30μm; the nitride is cubic phase BN, and the carbide is SiC with a particle size of 5μm.

[0102] Comparative Example 1:

[0103] The only difference between this comparative example and Example 1 is:

[0104] The thermally conductive filler is a carbon-based material, nitride, and oxide in a mass ratio of 1:7:10.

[0105] The carbon-based material is a carboxylated carbon nanotube.

[0106] The nitride is BN.

[0107] The BN is a cubic phase BN.

[0108] The oxide is TiO2, rutile type, with a particle size of 0.5 μm.

[0109] Comparative Example 2:

[0110] The only difference between this comparative example and Example 2 is:

[0111] The epoxy equivalent of the epoxy resin is 184-200 g / eq.

[0112] The epoxy resin is epoxy resin E51.

[0113] Comparative Example 3:

[0114] The only difference between this comparative example and Example 1 is:

[0115] The high thermal conductivity metal-based radiation heat dissipation coating is prepared by means of the following raw materials, by weight: 16 parts thermally conductive filler, 23 parts epoxy resin, 11.5 parts curing agent, and 10 parts dispersant.

[0116] The mass ratio of the thermally conductive filler to the epoxy resin is 16:23.

[0117] The mass ratio of the thermally conductive filler to the dispersant is 1.6:1.

[0118] The thermally conductive filler accounts for 26.45% of the system, and the dispersant accounts for 16.53% of the system.

[0119] The thermally conductive filler is a carbon-based material, nitride, and oxide in a mass ratio of 1:5:10.

[0120] The carbon-based material is a carboxylated carbon nanotube.

[0121] The nitride is cubic phase BN.

[0122] The oxides are Al2O3 and TiO2 in a mass ratio of 7:3.

[0123] Comparative Example 4:

[0124] The only difference between this comparative example and Example 1 is:

[0125] The high thermal conductivity metal-based radiation heat dissipation coating is prepared by means of the following raw materials, by weight: 10 parts thermally conductive filler, 23 parts epoxy resin, 11.5 parts curing agent, and 10 parts dispersant.

[0126] The mass ratio of the thermally conductive filler to the epoxy resin is 10:23.

[0127] The mass ratio of the thermally conductive filler to the dispersant is 1:1.

[0128] The thermally conductive filler and dispersant each account for 18.35% of the system.

[0129] The thermally conductive filler is a carbon-based material and a nitride, with a mass ratio of 1:9.

[0130] The carbon-based material is a carboxylated carbon nanotube.

[0131] The nitride is AlN.

[0132] Comparative Example 5:

[0133] The only difference between this comparative example and Example 1 is:

[0134] The high thermal conductivity metal-based radiation heat dissipation coating is prepared by means of the following raw materials, by weight: 18 parts thermally conductive filler, 40 parts epoxy resin, 20 parts curing agent, and 10 parts dispersant.

[0135] The mass ratio of the thermally conductive filler to the epoxy resin is 18:40.

[0136] The mass ratio of the thermally conductive filler to the dispersant is 1.8:1.

[0137] The thermally conductive filler accounts for 20.45% of the system, and the dispersant accounts for 11.36% of the system.

[0138] Comparative Example 6:

[0139] The only difference between this comparative example and Example 1 is:

[0140] The high thermal conductivity metal-based radiation heat dissipation coating is prepared by means of the following raw materials, by weight: 18 parts thermally conductive filler, 23 parts epoxy resin, 11.5 parts curing agent, and 10 parts dispersant.

[0141] The thermally conductive filler is composed of carbon-based materials, metal powder, and carbides in a mass ratio of 1:7:10.

[0142] The carbon-based material is a carboxylated multi-walled carbon nanotube.

[0143] The metal powder is conductive silver powder.

[0144] The carbide is silicon carbide.

[0145] Performance testing:

[0146] Infrared emissivity: In accordance with the JGJ / T287-2014 standard, the coating was self-leveled / sprayed onto a tinplate sheet with dimensions of 30mm×30mm×0.28mm, and the emissivity of the coating at 100℃ was tested using a Fourier transform infrared spectrometer.

[0147] Thermal conductivity: In accordance with GB / T22588-2008 standard, the coating was sprayed onto a 304 stainless steel cylinder with dimensions of Ø10mm×2mm, and the thermal conductivity of the coating was tested using a laser thermal conductivity meter.

[0148] Bending test: According to GB / T6742 standard, the coating is self-leveled / sprayed onto a tinplate sheet with a size of 120mm×50mm×0.28mm, and the film elasticity tester is used for testing.

[0149] Impact resistance test: According to GB / T1732-2020 standard, the coating is self-leveled / sprayed onto the tinplate sheet and tested using a paint film impact tester.

[0150] Abrasion resistance test: The test was conducted according to the gasoline immersion method in standard HG / T3343-1985. The coating was self-leveled / sprayed onto the tinplate sheet and tested using an abrasion tester. A weight of 1000g was loaded and the rotation speed was approximately 60 rpm. After 500 rpm, the data was observed and recorded.

[0151] Acid, alkali and oil aging test: According to the national standard GB / T1736, acid and alkali resistance tests were conducted using 5% NaOH and 10% HCl by mass.

[0152] The coatings obtained in the examples and comparative examples were tested, and the calculation results are shown in Table 1.

[0153] The infrared emissivity test values ​​for Example 1 are shown below. Figure 2 Example 1 shows the infrared emissivity test value at 100°C. Figure 3 See the actual image of the bending test in Example 1. Figure 4 The actual image of the coating impact resistance test in Embodiment 1 of the present invention is shown below. Figure 5 Example 1: Actual image of the coating abrasion resistance test. (See attached image.) Figure 6 Example 1: Actual photos of the coating's resistance to acid, alkali, and oil aging, as shown in the image. Figure 7 .

[0154] Table 1 Performance Test Results

[0155]

[0156] From Table 1 and Figures 2-7 It can be seen that the high thermal conductivity metal-based radiation heat dissipation coatings prepared in Examples 1-3 exhibit excellent thermal conductivity, infrared emissivity, and physical properties. In Comparative Example 1, TiO2 was used to replace SiC carbide in the thermally conductive filler, and the thermal conductivity of TiO2 is 6-10 W·m. -1 ·K -1 Its thermal conductivity is 120 W·m lower than that of SiC. -1 ·K -1 Therefore, the thermal conductivity of the coating in Comparative Example 1 decreased sharply. Comparative Example 2 replaced epoxy resin E44 with epoxy resin E51. The bending resistance and impact resistance of E51 were lower than those of E44 because E51 has a slightly higher epoxy value, resulting in a higher crosslinking density after curing and a harder coating, but its toughness and impact resistance were relatively reduced. Comparative Example 3 modified the composition and proportion of the thermally conductive filler, introducing oxides Al2O3 and TiO2. Comparative Example 4 not only reduced the weight of the thermally conductive filler but also did not add carbides. The resulting high thermal conductivity metal-based radiation heat dissipation coating showed a thermal conductivity of 30 W·m compared to the traditional thermally conductive material using Al2O3 as the filler. -1 ·K -1The thermal conductivity of Al2O3 is still lower than that of silicon carbide. Furthermore, due to its large specific surface area, Al2O3 tends to increase the overall viscosity of the coating, making spraying difficult. In Comparative Example 5, the addition of epoxy resin resulted in a sharp decrease in thermal conductivity. This is because polymers such as epoxy are generally poor conductors of heat, leading to heat accumulation and a significant decrease in the coating's thermal conductivity. In Comparative Example 6, the thermally conductive powder was replaced with carbon-based materials, metal powder, and carbides, and the nitride was replaced with metallic silver powder. The thermal conductivity of silver powder is 427 W·m. -1 ·K -1 Its thermal conductivity is 185-300 W·m higher than that of BN. -1 ·K -1 However, silver powder has a much higher density than epoxy resin, making it prone to deposition and aggregation in coatings. Furthermore, its dispersibility in coatings is poor, making dispersion difficult and leading to a decrease in coating performance, which in turn reduces its thermal conductivity.

[0157] Therefore, this invention proposes a high thermal conductivity metal-based radiation heat dissipation coating and its preparation method. The thermal conductivity of the prepared coating can reach more than 30 W / (m·K), and the infrared emissivity of the atmospheric window at 100℃ is greater than 95%. At the same time, it has excellent impact resistance, wear resistance, and acid and alkali oil aging resistance, and is suitable for efficient heat dissipation of metal-based heat sources such as motors, engines, and photovoltaic backsheets.

[0158] 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 high thermal conductivity metal-based radiative heat dissipation coating, characterized in that, Its raw materials include thermally conductive fillers, epoxy resin, curing agents, and dispersants; The mass ratio of the thermally conductive filler to the epoxy resin is 1:(1-2). The thermally conductive filler includes one or more of carbon-based materials, nitrides, and carbides; The particle size of the nitride and carbide is 1-5 μm; the nitride is BN; the carbide is SiC; The carbon-based material is a multi-walled material.

2. The high thermal conductivity metal-based radiative heat dissipation coating according to claim 1, characterized in that... The mass ratio of the carbon-based material, nitride, and carbide is 1:(6-8):(8-13).

3. The high thermal conductivity metal-based radiative heat dissipation coating according to claim 1, characterized in that, The epoxy resin has an epoxy equivalent of 210-240 g / eq and a softening point of 14-23℃.

4. The high thermal conductivity metal-based radiative heat dissipation coating according to claim 1, characterized in that, The curing agent is one of polyamide 650, polyamide 651, polyamide 5140, and polyetheramine D230.

5. The high thermal conductivity metal-based radiative heat dissipation coating according to claim 1, characterized in that, The dispersant is one or more of isopropanol, methyl methyl isobutyl ketone, xylene, and n-butanol.

6. A method for preparing a high thermal conductivity metal-based radiation heat dissipation coating according to any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Prepare the dispersion; S2. Prepare a thermally conductive filler dispersion solution; S3. Preparation of epoxy resin thermally conductive coating; S4. Prepare a high thermal conductivity radiation heat dissipation coating.

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