High-thermal-conductivity radiation refrigeration heat dissipation coating for LED lighting module and preparation method thereof

Abstract

The application belongs to the technical field of coating preparation, and provides high-heat-conducting radiation refrigeration heat dissipation coating for LED lighting modules and a preparation method thereof; first, dopamine and tannic acid are used to cooperatively coat hexagonal boron nitride sheets, and zinc oxide is deposited in situ to obtain sheet-shaped heat-conducting fillers with low interface thermal resistance; second, magnesium silicate is hydrothermally generated using a lignocellulose template, is locally carbonized under a nitrogen atmosphere, and is grafted with aminopropyl silane to form a heat-conducting framework; third, gadolinium-doped calcium titanate hollow spheres are prepared by a citric acid complexation method, and an aluminum oxide-phosphate double-shell housing is constructed, and the three kinds of functional particles are high-speed dispersed with methyl-phenyl siloxane resin, a coupling agent and a low-volatile solvent at a predetermined ratio, and are vacuum defoamed to obtain the high-heat-conducting radiation refrigeration heat dissipation coating for LED lighting modules.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coating preparation, and relates to high-thermal-conductivity radiation refrigeration heat dissipation coating for LED lighting module and a preparation method thereof. BACKGROUND

[0002] As a solid-state light source, the light-emitting efficiency of LED is continuously improved, but most of the electric energy is still accumulated in the chip junction area in the form of heat. If heat dissipation is not timely, the junction temperature rise will lead to severe light decay, color drift and even failure, thereby shortening the life of the lamp and affecting the light quality. The existing heat dissipation scheme mainly relies on metal heat dissipation fins, heat-conductive silicone grease and black coating. Although the traditional black paint can improve the surface emissivity, it lacks sufficient heat conduction capacity; a single filler type heat-conductive coating (such as aluminum nitride, boron nitride or aluminum oxide) is difficult to meet the requirements of high thermal conductivity and high emissivity under thin film conditions due to the filling limit, interface adhesion and cost reasons. Some coatings introduce graphene, carbon nanotubes or diamond, but it is difficult to disperse, or fluorination treatment or chemical vapor deposition is used to obtain low interface thermal resistance, but the process requires high vacuum, strong corrosive gas or high energy consumption equipment, and the safety and environmental protection pressure is high, which is not conducive to the introduction of conventional production lines of large-scale lighting enterprises. SUMMARY

[0003] In view of the deficiencies in the prior art, the purpose of the present application is to provide high-thermal-conductivity radiation refrigeration heat dissipation coating for LED lighting module and a preparation method thereof. First, dopamine-tannic acid bilayer and zinc oxide in-situ deposition technology are used to composite coat boron nitride sheet to obtain a heat-conductive unit with low interface thermal resistance; second, wood cellulose is used as a template to grow magnesium silicate crystal rods, and after local carbonization in nitrogen, amino propyl silane is grafted to form a longitudinal heat-conductive bridge; third, ytterbium-doped calcium titanate hollow spheres are prepared by citric acid complexation method, thereby meeting the needs of actual production.

[0004] To achieve this purpose, the present application adopts the following technical solutions:

[0005] In the first aspect, the present application provides a preparation method of high-thermal-conductivity radiation refrigeration heat dissipation coating for LED lighting module, which comprises:

[0006] S1, hexagonal boron nitride sheet powder is added to deionized water dispersion, dopamine hydrochloride and Tris buffer are put in, tannic acid and zinc acetate aqueous solution are added, and modified boron nitride sheet powder is obtained;

[0007] S2, wood cellulose powder is dispersed in deionized water, magnesium chloride hexahydrate and sodium silicate nonahydrate are added in sequence to obtain a slurry, the slurry is transferred to an autoclave for reaction, the product is filtered and dried, and then carbonized in a nitrogen atmosphere to obtain a powder, and after cooling, the powder is put into anhydrous ethanol, and gamma-aminopropyl triethoxysilane is added to obtain magnesium silicate powder;

[0008] S3, dissolve calcium nitrate tetrahydrate in deionized water, add citric acid complex, add tetrabutyl titanate and ytterbium nitrate pentahydrate under ice bath condition to obtain a gel, dry the gel, pre-calcine and keep warm to obtain calcium titanate balls, disperse the calcium titanate balls in deionized water, add aluminum nitrate nonahydrate, filter, dry and calcine, spray into a phosphoric acid solution and solidify to obtain calcium titanate hollow sphere powder;

[0009] S4, mix methylphenyl silicone resin, modified boron nitride flake powder, magnesium silicate powder and calcium titanate hollow sphere powder, add γ-glycidoxypropyl triethoxysilane and dipropylene glycol methyl ether, and obtain a high-thermal-conductivity radiation refrigeration heat dissipation coating for an LED lighting module after degassing.

[0010] Specifically includes:

[0011] S1, add hexagonal boron nitride flake powder to deionized water for shearing dispersion, add dopamine hydrochloride and Tris buffer to adjust the pH to 8.3-8.7, add tannic acid and zinc acetate aqueous solution to adjust the pH to 9.5-10.5, and obtain modified boron nitride flake powder after filtration, washing and drying;

[0012] S2, disperse wood cellulose powder in deionized water, add magnesium chloride hexahydrate and sodium silicate nonahydrate in sequence to obtain a slurry, transfer the slurry to an autoclave, react at a first temperature, dry the product, carbonize in a nitrogen atmosphere at a second temperature, and obtain magnesium silicate powder after cooling, adding γ-aminopropyl triethoxysilane and refluxing and stirring at a third temperature.

[0013] S3, dissolve calcium nitrate tetrahydrate in deionized water, heat to a fourth temperature and add citric acid complex, add tetrabutyl titanate and ytterbium nitrate pentahydrate under ice bath condition to obtain a gel, dry the gel, pre-calcine and keep warm to obtain calcium titanate balls, disperse the calcium titanate balls in deionized water, add aluminum nitrate nonahydrate, adjust the pH to 7.8-8.2 and react, filter, dry and calcine at a seventh temperature, spray into a phosphoric acid solution and solidify to obtain calcium titanate hollow sphere powder;

[0014] S4, mix methylphenyl silicone resin, modified boron nitride flake powder, magnesium silicate powder and calcium titanate hollow sphere powder, add γ-glycidoxypropyl triethoxysilane and dipropylene glycol methyl ether, and obtain a high-thermal-conductivity radiation refrigeration heat dissipation coating for an LED lighting module after degassing.

[0015] The surface of boron nitride sheet is chemically inert. First, a layer of polydopamine film rich in hydroxyl, amine and pyrrole ring is generated by self-oxidation and polymerization of the ortho-benzene diol and amine structure of dopamine in a weak alkaline Tris medium. The film is closely adsorbed with boron nitride through π-π stacking, and at the same time provides coordination sites for subsequent reactions with the help of surface functional groups. Then tannic acid is introduced, and the multiple ortho-phenolic hydroxyl groups in tannic acid can form hydrogen bonds and ester bonds with the amine and phenolic hydroxyl groups on the polydopamine, further constructing a cross-linked and dense polyphenol network to improve the mechanical toughness and chemical stability of the shell layer. Zinc complexes are added to the system and the base is adjusted, and the catechol groups in the polydopamine layer coordinate with zinc ions, causing zinc ions to be adsorbed and locally enriched; under alkaline conditions, zinc ions hydrolyze to form zinc hydroxide and are dehydrated to form nanometer-sized zinc oxide, which is uniformly deposited on the surface of the polyphenol network. The nanometer-sized zinc oxide dots are connected to the polyphenol shell layer by coordination bonds, reducing the thermal resistance at the filler-resin interface.

[0016] Lignocellulose naturally has a large number of hydroxyl groups. In a hydrothermal environment, magnesium ions and silicate ions are first coordinated and condensed, and magnesium silicate crystal nuclei are rapidly deposited on the surface of the fibers and grow outward along the fiber axis, eventually forming a continuous inorganic shell while retaining the organic skeleton inside. Subsequently, the product is subjected to mild carbonization in a nitrogen atmosphere, and the cellulose skeleton is partially dehydrated and deoxidized and rearranged into graphitized micro-carbon filaments, which are densely covered by the inorganic shell. Ammonia propyl silane is introduced, and the silane hydroxyl groups are condensed with the hydroxyl groups of the inorganic shell. The ammonia propyl group extends outward and can further condense with the silicone resin during subsequent curing, significantly reducing the interfacial contact resistance. The magnesium silicate rod has both a longitudinal rigid crystal lattice heat conduction channel and a carbon core and silane layer that enables tight coupling with the resin.

[0017] Citric acid coordinates with calcium ions and titanate ions to form a uniform metal-organic gel; ytterbium ions incorporated into the gel framework share positions with calcium-titanium oxygen octahedra. During subsequent temperature decomposition, citric acid is cracked to release gas and leave a carbon-rich void skeleton, accompanied by rearrangement of the calcium titanate crystal phase, resulting in hollow structures inside the spherical particles, with ytterbium ions remaining stable in the crystal lattice. Next, aluminum hydroxide is deposited in a mild alkaline aqueous system, and is converted to a nanoscale alumina shell after low-temperature calcination, providing mechanical reinforcement and heat resistance barrier. Phosphoric acid aqueous solution is then sprayed and solidified, and phosphate ions form a dense coordination layer on the surface of the alumina, blocking water vapor and ion erosion. The resulting hollow calcium titanate sphere has a heat storage cavity inside, and the double shell on the outside has both structural stability and moisture-proof function. The ytterbium-doped perovskite crystal produces a strong absorption-emission band in the mid-infrared atmospheric window, which can simultaneously play a role in radiative cooling in the heat conduction network.

[0018] As a preferred technical solution of the present application, in S1, the mass ratio of the hexagonal boron nitride flaky powder, deionized water, dopamine hydrochloride, Tris buffer, tannic acid and zinc acetate aqueous solution is (100-110):(2000-2200):(1.8-2.2):(1.8-2.2):(1.8-2.2):(193-235), for example, it can be (100, 101, 102, 103, 104, 105, 106, 107, 108, 109 or 110):(2000, 2020, 2040, 2060, 2080, 2100, 2120, 2140, 2160, 2180 or 2200):(1.8, 1.84, 1.88, 1.92, 1.96, 2.0, 2.04, 2.08, 2.12, 2.16 or 2.2):(1.8, 1.84, 1.88, 1.92, 1.96, 2.0, 2.04, 2.08, 2.12, 2.16 or 2.2):(1.8, 1.84, 1.88, 1.92, 1.96, 2.0, 2.04, 2.08, 2.12, 2.16 or 2.2):(193, 197.2, 201.4, 205.6, 209.8, 214, 218.2, 222.4, 226.6, 230.8 or 235), but not limited to the listed values, other values not listed in the range are also applicable.

[0019] In some optional examples, the mass fraction of the zinc acetate aqueous solution is 6-8wt.%, for example, it can be 6wt.%, 6.2wt.%, 6.4wt.%, 6.6wt.%, 6.8wt.%, 7wt.%, 7.2wt.%, 7.4wt.%, 7.6wt.%, 7.8wt.% or 8wt.%, but not limited to the listed values, other values not listed in the range are also applicable.

[0020] As a preferred technical solution of the present application, in S2, the mass ratio of the lignocellulose powder, magnesium chloride hexahydrate and sodium silicate nonahydrate is (18-22):(54-66):(36-44), for example, it can be (18, 18.4, 18.8, 19.2, 19.6, 20, 20.4, 20.8, 21.2, 21.6 or 22):(54, 55.2, 56.4, 57.6, 58.8, 60, 61.2, 62.4, 63.6, 64.8 or 66):(36, 36.9, 37.8, 38.7, 39.6, 40.5, 41.4, 42.3, 43.2, 44.1 or 44), but not limited to the listed values, other values not listed in the range are also applicable.

[0021] In some alternative examples, the first temperature is 175-185 °C, for example, it can be 175 °C, 176 °C, 177 °C, 178 °C, 179 °C, 180 °C, 181 °C, 182 °C, 183 °C, 184 °C or 185 °C, but not limited to the listed values, other values not listed in the range are also applicable.

[0022] In some alternative examples, the time of the first temperature reaction is 7-9 h, for example, it can be 7 h, 7.2 h, 7.4 h, 7.6 h, 7.8 h, 8 h, 8.2 h, 8.4 h, 8.6 h, 8.8 h or 9 h, but not limited to the listed values, other values not listed in the range are also applicable.

[0023] In some alternative examples, the second temperature is 290-310 °C, for example, it can be 290 °C, 292 °C, 294 °C, 296 °C, 298 °C, 300 °C, 302 °C, 304 °C, 306 °C, 308 °C or 310 °C, but not limited to the listed values, other values not listed in the range are also applicable.

[0024] In some alternative examples, the time of carbonization is 0.8-1.2 h, for example, it can be 0.8 h, 0.84 h, 0.88 h, 0.92 h, 0.96 h, 1.0 h, 1.04 h, 1.08 h, 1.12 h, 1.16 h or 1.2 h, but not limited to the listed values, other values not listed in the range are also applicable.

[0025] In some alternative examples, the mass ratio of the powder, anhydrous ethanol and γ-aminopropyl triethoxysilane is 100: (90-100): (1.8-2.2), for example, it can be 100: (90, 91, 92, 93, 94, 95, 96, 97, 98, 99 or 100): (1.8, 1.84, 1.88, 1.92, 1.96, 2.0, 2.04, 2.08, 2.12, 2.16 or 2.2), but not limited to the listed values, other values not listed in the range are also applicable.

[0026] In some alternative examples, the third temperature is 55-65 °C, for example, it can be 55 °C, 56 °C, 57 °C, 58 °C, 59 °C, 60 °C, 61 °C, 62 °C, 63 °C, 64 °C or 65 °C, but not limited to the listed values, other values not listed in the range are also applicable.

[0027] In some optional examples, the time for the reflux stirring is 1.5-2.5h, for example, it can be 1.5h, 1.6h, 1.7h, 1.8h, 1.9h, 2.0h, 2.1h, 2.2h, 2.3h, 2.4h or 2.5h, but not only limited to the listed values, other values not listed in the range of values are also applicable.

[0028] As a preferred technical solution of the present application, in S3, the mass ratio of the calcium nitrate tetrahydrate, citric acid, tetrabutyl titanate and ytterbium nitrate pentahydrate is (53-65):(104-126):(61-75):(6-8), for example, it can be (53, 54.2, 55.4, 56.6, 57.8, 59, 60.2, 61.4, 62.6, 63.8 or 65):(104, 106.2, 108.4, 110.6, 112.8, 115, 117.2, 119.4, 121.6, 123.8 or 126):(61, 62.4, 63.8, 65.2, 66.6, 68, 69.4, 70.8, 72.2, 73.6 or 75):(6, 6.2, 6.4, 6.6, 6.8, 7.0, 7.2, 7.4, 7.6 or 8), but not only limited to the listed values, other values not listed in the range of values are also applicable.

[0029] In some optional examples, the fourth temperature is 78-82℃, for example, it can be 78℃, 78.4℃, 78.8℃, 79.2℃, 79.6℃, 80℃, 80.4℃, 80.8℃, 81.2℃, 81.6℃ or 82℃, but not only limited to the listed values, other values not listed in the range of values are also applicable.

[0030] In some optional examples, the fifth temperature is 280-320℃, for example, it can be 280℃, 284℃, 288℃, 292℃, 296℃, 300℃, 304℃, 308℃, 312℃, 316℃ or 320℃, but not only limited to the listed values, other values not listed in the range of values are also applicable.

[0031] In some optional examples, the time for the pre-calcination is 1.5-2.5h, for example, it can be 1.5h, 1.6h, 1.7h, 1.8h, 1.9h, 2.0h, 2.1h, 2.2h, 2.3h, 2.4h or 2.5h, but not only limited to the listed values, other values not listed in the range of values are also applicable.

[0032] In some optional examples, the mass fraction of the phosphoric acid solution is 85wt.%.

[0033] In some optional examples, the sixth temperature is 640-660℃, for example, can be 640℃, 642℃, 644℃, 646℃, 648℃, 650℃, 652℃, 654℃, 656℃, 658℃ or 660℃, but not only limited to the listed values, other values not listed in the range of values are also applicable.

[0034] In some optional examples, the time for the sixth temperature holding is 1.5-2.5h, for example, can be 1.5h, 1.6h, 1.7h, 1.8h, 1.9h, 2.0h, 2.1h, 2.2h, 2.3h, 2.4h or 2.5h, but not only limited to the listed values, other values not listed in the range of values are also applicable.

[0035] In some optional examples, the mass ratio of the calcium titanate ball, aluminum nitrate nonahydrate and phosphoric acid solution is (95-100):(6-8):(0.4-0.6), for example, can be (95, 95.5, 96, 96.5, 97, 97.5, 98, 98.5, 99, 99.5 or 100):(6, 6.2, 6.4, 6.6, 6.8, 7.0, 7.2, 7.4, 7.6 or 8):(0.4, 0.42, 0.44, 0.46, 0.48, 0.5, 0.52, 0.54, 0.56, 0.58 or 0.6), but not only limited to the listed values, other values not listed in the range of values are also applicable.

[0036] In some optional examples, the time for adjusting the pH to 7.8-8.2 and reacting is 0.8-1.2h, for example, can be 0.8h, 0.84h, 0.88h, 0.92h, 0.96h, 1.0h, 1.04h, 1.08h, 1.12h, 1.16h or 1.2h, but not only limited to the listed values, other values not listed in the range of values are also applicable.

[0037] In some optional examples, the seventh temperature is 290-310℃, for example, can be 290℃, 292℃, 294℃, 296℃, 298℃, 300℃, 302℃, 304℃, 306℃, 308℃ or 310℃, but not only limited to the listed values, other values not listed in the range of values are also applicable.

[0038] In some optional examples, the time for the seventh temperature calcination is 1-2h, for example, can be 1h, 1.1h, 1.2h, 1.3h, 1.4h, 1.5h, 1.6h, 1.7h, 1.8h, 1.9h or 2h, but not only limited to the listed values, other values not listed in the range of values are also applicable.

[0039] In some optional examples, the temperature of the curing is 115-125℃, for example, it can be 115℃, 116℃, 117℃, 118℃, 119℃, 120℃, 121℃, 122℃, 123℃, 124℃ or 125℃, but not only limited to the listed values, other values in the range of the values are also applicable.

[0040] In some optional examples, the time of the curing is 1-1.5h, for example, it can be 1h, 1.05h, 1.1h, 1.15h, 1.2h, 1.25h, 1.3h, 1.35h, 1.4h, 1.45h or 1.5h, but not only limited to the listed values, other values in the range of the values are also applicable.

[0041] As a preferred technical solution of the present application, in S4, the mass ratio of the methylphenyl silicone resin, modified boron nitride flake powder, magnesium silicate powder, calcium titanate hollow sphere powder, γ-glycidoxypropyltriethoxysilane and dipropylene glycol methyl ether is (270-330):(150-185):(200-230):(125-155):(6-8):(80-90), for example, it can be (270, 276, 282, 288, 294, 300, 306, 312, 318, 324 or 330):(150, 153.5, 157, 160.5, 164, 167.5, 171, 174.5, 178, 181.5 or 185):(200, 203, 206, 209, 212, 215, 218, 221, 224, 227 or 230):(125, 128, 131, 134, 137, 140, 143, 146, 149, 152 or 155):(6, 6.2, 6.4, 6.6, 6.8, 7.0, 7.2, 7.4, 7.6, 7.8 or 8):(80, 81, 82, 83, 84, 85, 86, 87, 88, 89 or 90), but not only limited to the listed values, other values in the range of the values are also applicable.

[0042] In the second aspect, the present application provides a high-thermal-radiation refrigeration heat dissipation coating for LED lighting modules prepared by the preparation method of the first aspect.

[0043] Compared with the prior art, the beneficial effects of the present application are: (1) by the synergistic effect of modified boron nitride flake powder, magnesium silicate powder and calcium titanate hollow sphere powder, an efficient heat conduction path is constructed, the modified boron nitride provides the main heat conduction path, and the magnesium silicate and calcium titanate effectively enhance the overall heat conduction performance of the coating by reducing the interfacial thermal resistance and optimizing the heat conduction path; (2) the surface infrared emission characteristics of the modified boron nitride and the magnesium silicate, and the porous structure and infrared emission capability of the calcium titanate hollow sphere, together improve the infrared radiation performance of the coating, especially in the atmospheric window band to achieve efficient heat dissipation, achieving passive radiation refrigeration effect; (3) the methylphenyl silicone resin as polysiloxane has high thermal stability, excellent ultraviolet resistance and moisture resistance, so that the material can still maintain structural integrity and performance stability in extreme environments such as high temperature and strong light, improving the uniform dispersibility and long-term reliability of the system. DETAILED DESCRIPTION

[0044] The technical solutions of the present application will be described in detail below in combination with specific embodiments. The embodiments described herein are specific specific embodiments of the present application, which are used to illustrate the concept of the present application; these descriptions are all explanatory and exemplary, and should not be understood as limiting the embodiments of the present application and the protection scope of the present application. In addition to the embodiments described herein, those skilled in the art can also employ other technical solutions that are obvious based on the content disclosed in the claims and the specification of the present application, which include technical solutions that make any obvious substitutions and modifications to the embodiments described herein.

[0045] The chemical reagents used in the embodiments and comparative examples of the present application are all commercially available goods and are not subjected to any further purification treatment.

[0046] Example 1

[0047] The present embodiment provides a high-heat-conducting radiation refrigeration heat dissipation coating for LED lighting module and a preparation method thereof, and the preparation method specifically comprises the following steps:

[0048] S1, 100g of hexagonal boron nitride flake powder is added to 2000g of deionized water for shearing dispersion, 1.8g of dopamine hydrochloride and 1.8g of Tris buffer are added, the pH is adjusted to 8.3, 1.8g of tannic acid and zinc acetate aqueous solution are added, the pH is adjusted to 9.5, and then the mixture is subjected to suction filtration, washing and drying to obtain modified boron nitride flake powder;

[0049] S2, 18 g of lignocellulose powder was dispersed in deionized water, 54 g of magnesium chloride hexahydrate and 36 g of sodium silicate nonahydrate were added in sequence to obtain a slurry, the slurry was transferred to an autoclave, reacted at 175 ℃ for 7 h, the product was filtered, dried, and then carbonized at 290 ℃ in a nitrogen atmosphere for 0.8 h, after cooling, 100 g of the powder was put into 90 g of anhydrous ethanol, 1.8 g of γ-aminopropyltriethoxysilane was added, and reflux stirring was carried out at 55 ℃ for 1.5 h to obtain magnesium silicate powder;

[0050] S3, 53 g of calcium nitrate tetrahydrate was dissolved in deionized water, heated to 78 ℃ and added with 104 g of citric acid complex, 61 g of tetrabutyl titanate and 6 g of ytterbium nitrate pentahydrate were added under ice bath condition to obtain a gel, the gel was dried and dehydrated, precalcined at 280 ℃ for 1.5 h, and then heated to 640 ℃ for 1.5 h to obtain calcium titanate balls, the calcium titanate balls were dispersed in deionized water, 6 g of aluminum nitrate nonahydrate was added, the pH was adjusted to 7.8 and reacted for 0.8 h, after filtration and drying, 290 ℃ calcination was carried out for 1 h, 0.4 g of 85 wt.% phosphoric acid solution was sprayed, and 115 ℃ solidification was carried out for 1 h to obtain calcium titanate hollow ball powder;

[0051] S4, 270 g of 60% solid content methylphenyl silicone resin, 150 g of modified boron nitride flake powder, 200 g of magnesium silicate powder and 125 g of calcium titanate hollow ball powder were mixed, 6 g of γ-glycidoxypropyltriethoxysilane and 80 g of dipropylene glycol methyl ether were added, and after degassing, a high-thermal-conductivity radiation refrigeration heat dissipation coating for an LED lighting module was obtained.

[0052] Example 2

[0053] The embodiment provides a high-thermal-conductivity radiation refrigeration heat dissipation coating for an LED lighting module and a preparation method thereof, and the preparation method specifically comprises the following steps:

[0054] S1, 105 g of hexagonal boron nitride flake powder was added to 2150 g of deionized water for shearing dispersion, 2.1 g of dopamine hydrochloride and 2.1 g of Tris buffer were added, the pH was adjusted to 8.6, 2.1 g of tannic acid and zinc acetate aqueous solution were added, the pH was adjusted to 10.2, and after filtration, washing and drying, modified boron nitride flake powder was obtained;

[0055] S2, 19 g of lignocellulose powder was dispersed in deionized water, 62 g of magnesium chloride hexahydrate and 42 g of sodium silicate nonahydrate were added in sequence to obtain a slurry, the slurry was transferred to an autoclave, reacted at 182 ℃ for 8.5 h, the product was filtered, dried, and then carbonized at 305 ℃ in a nitrogen atmosphere for 1.1 h, after cooling, 100 g of the powder was put into 98 g of anhydrous ethanol, 2.1 g of γ-aminopropyltriethoxysilane was added, and reflux stirring was carried out at 62 ℃ for 2.2 h to obtain magnesium silicate powder;

[0056] S3, dissolve 62 g of calcium nitrate tetrahydrate in deionized water, heat to 81℃ and add 120 g of citric acid complex, add 72 g of tetrabutyl titanate and 7.5 g of ytterbium nitrate pentahydrate under ice bath conditions to obtain a gel, dry the gel by drying, and place it in a 310℃ pre-calcination for 2.2h, and then heat it to 655℃ and keep it for 2.2h to obtain calcium titanate balls, disperse the calcium titanate balls in deionized water, add 7.5 g of aluminum nitrate nonahydrate, adjust the pH to 8.1 and react for 1.1h, dry after filtration, and then calcine at 305℃ for 1.8h, spray 0.55 g of 85wt.% phosphoric acid solution and solidify at 122℃ for 1.3h to obtain calcium titanate hollow sphere powder;

[0057] S4, mix 310 g of methylphenyl silicone resin with a solid content of 60%, 160 g of modified boron nitride flake powder, 220 g of magnesium silicate powder, and 150 g of calcium titanate hollow sphere powder, then add 7.5 g of γ-glycidoxypropyltriethoxysilane and 88 g of dipropylene glycol methyl ether, and then deaerate to obtain a high-thermal-conductivity radiation refrigeration heat dissipation coating for an LED lighting module.

[0058] Example 3

[0059] The present embodiment provides a high-thermal-conductivity radiation refrigeration heat dissipation coating for an LED lighting module and a preparation method thereof, and the preparation method specifically comprises the following steps:

[0060] S1, add 108 g of hexagonal boron nitride flake powder to 2100 g of deionized water and shear disperse, add 2.0 g of dopamine hydrochloride and 2.0 g of Tris buffer, adjust the pH to 8.5, add 2.0 g of tannic acid and zinc acetate aqueous solution, adjust the pH to 10.0, and then filter, wash and dry to obtain modified boron nitride flake powder;

[0061] S2, disperse 20 g of wood cellulose powder in deionized water, and then add 60 g of magnesium chloride hexahydrate and 40 g of sodium silicate nonahydrate to obtain a slurry, transfer the slurry to an autoclave, react at 180℃ for 8h, dry the product, and then carbonize it at 300℃ in a nitrogen atmosphere for 1.0h, cool it, and then add 100 g of the powder to 95 g of anhydrous ethanol, add 2.0 g of γ-aminopropyltriethoxysilane, and then reflux and stir at 60℃ for 2.0h to obtain magnesium silicate powder;

[0062] S3, dissolve 60 g of calcium nitrate tetrahydrate in deionized water, heat to 80℃ and add 115 g of citric acid complex, add 70 g of tetrabutyl titanate and 7 g of ytterbium nitrate pentahydrate under ice bath conditions to obtain a gel, dry the gel by drying, and place it in a 300℃ pre-calcination for 2.0 h, and then heat to 650℃ and keep for 2.0 h to obtain calcium titanate balls, disperse the calcium titanate balls in deionized water, add 7 g of aluminum nitrate nonahydrate, adjust the pH to 8.0 and react for 1.0 h, dry after filtration, and then calcine at 300℃ for 1.5 h, spray 0.5 g of 85wt.% phosphoric acid solution and solidify at 120℃ for 1.2 h to obtain calcium titanate hollow sphere powder;

[0063] S4, mix 300 g of methylphenyl silicone resin with a solid content of 60%, 170 g of modified boron nitride flake powder, 210 g of magnesium silicate powder, and 140 g of calcium titanate hollow sphere powder, then add 7 g of γ-glycidoxypropyltriethoxysilane and 85 g of dipropylene glycol methyl ether, and then deaerate to obtain a high-thermal-conductivity radiation refrigeration heat dissipation coating for an LED lighting module.

[0064] Example 4

[0065] The present embodiment provides a high-thermal-conductivity radiation refrigeration heat dissipation coating for an LED lighting module and a preparation method thereof, and the preparation method specifically comprises the following steps:

[0066] S1, add 110 g of hexagonal boron nitride flake powder to 2200 g of deionized water and shear disperse, add 2.2 g of dopamine hydrochloride and 2.2 g of Tris buffer, adjust the pH to 8.7, add 2.2 g of tannic acid and zinc acetate aqueous solution, and adjust the pH to 10.5, then filter, wash and dry to obtain modified boron nitride flake powder;

[0067] S2, disperse 22 g of wood cellulose powder in deionized water, and then add 66 g of magnesium chloride hexahydrate and 44 g of sodium silicate nonahydrate to obtain a slurry, transfer the slurry to an autoclave, react at 185℃ for 9 h, dry the product, and then carbonize it at 310℃ in a nitrogen atmosphere for 1.2 h, then cool it, add 100 g of the powder to 100 g of anhydrous ethanol, add 2.2 g of γ-aminopropyltriethoxysilane, and reflux stir at 65℃ for 2.5 h to obtain magnesium silicate powder;

[0068] S3, dissolve 65 g of calcium nitrate tetrahydrate in deionized water, heat to 82°C and add 126 g of citric acid complex, add 75 g of tetrabutyl titanate and 8 g of ytterbium nitrate pentahydrate under ice bath conditions to obtain a gel, dry the gel by baking, pre-calcine at 320°C for 2.5 h, heat to 660°C and keep for 2.5 h to obtain calcium titanate balls, disperse the calcium titanate balls in deionized water, add 8 g of aluminum nitrate nonahydrate, adjust the pH to 8.2 and react for 1.2 h, dry after filtration and bake at 310°C for 2 h, spray 0.6 g of 85 wt.% phosphoric acid solution and solidify at 125°C for 1.5 h to obtain calcium titanate hollow sphere powder;

[0069] S4, mix 330 g of methylphenyl silicone resin with a solid content of 60%, 185 g of modified boron nitride flake powder, 230 g of magnesium silicate powder and 155 g of calcium titanate hollow sphere powder, add 8 g of γ-glycidoxypropyltriethoxysilane and 90 g of dipropylene glycol methyl ether, and defoam to obtain a high-thermal-conductivity radiation refrigeration heat dissipation coating for an LED lighting module.

[0070] Comparative Example 1

[0071] This comparative example provides a high-thermal-conductivity radiation refrigeration heat dissipation coating for an LED lighting module and a preparation method thereof, which is different from Example 1 in that the mass of modified boron nitride flake powder in S4 is 0, and other process parameters and operating conditions are exactly the same as those in Example 1.

[0072] Comparative Example 2

[0073] This comparative example provides a high-thermal-conductivity radiation refrigeration heat dissipation coating for an LED lighting module and a preparation method thereof, which is different from Example 1 in that the mass of magnesium silicate powder in S4 is 0, and other process parameters and operating conditions are exactly the same as those in Example 1.

[0074] Comparative Example 3

[0075] This comparative example provides a high-thermal-conductivity radiation refrigeration heat dissipation coating for an LED lighting module and a preparation method thereof, which is different from Example 1 in that the mass of calcium titanate hollow sphere powder in S4 is 0, and other process parameters and operating conditions are exactly the same as those in Example 1.

[0076] The test method for solar reflectance and hemispherical emissivity is GB / T25261-2018. The test method for atmospheric window (8-13 μm) emissivity is to use a reflectometer, such as a SOC-100 Hemispherical Directional Reflectometer, to test the infrared emissivity at a wavelength of 8-13 μm, i.e. the atmospheric window emissivity. The test method for thermal conductivity is ASTM-E1530-06. The test results are shown in Table 1.

[0077] Table 1 Test results of high thermal conductivity radiation refrigeration paint for LED lighting module of Example 1-Example 4 and Comparative Example 1-Comparative Example 3

[0078] Solar reflectance (%) Hemispherical emittance (%) Atmospheric window emittance (%) Thermal conductivity (W / m-K) Example 1 90 88 90 0.58 Example 2 91 90 92 0.55 Example 3 92 89 91 0.57 Example 4 91 91 91 0.56 Comparative Example 1 84 79 81 0.37 Comparative Example 2 82 80 78 0.42 Comparative Example 3 78 76 75 0.50

[0079] As shown in Table 1, compared with Example 1, the solar reflectance, hemispherical emissivity, atmospheric window (8-13 μm) emissivity and thermal conductivity of Comparative Example 1 all decrease; the solar reflectance, hemispherical emissivity, atmospheric window (8-13 μm) emissivity and thermal conductivity of Comparative Example 2 all decrease; the solar reflectance, hemispherical emissivity, atmospheric window (8-13 μm) emissivity and thermal conductivity of Comparative Example 3 all decrease. The boron nitride sheet has high in-plane thermal conductivity, can build efficient thermal conduction channels in the coating, and its sheet structure can also provide certain scattering and infrared emission enhancement. Comparative Example 1 lacks modified boron nitride sheet powder, so the radiation refrigeration effect of Comparative Example 1 decreases, and the thermal conductivity decreases. The one-dimensional structure of magnesium silicate rod powder can play a role in the thermal conduction path in the coating, and is beneficial to light scattering and infrared emission in a certain waveband. Comparative Example 2 lacks magnesium silicate powder, so the radiation refrigeration effect of Comparative Example 2 decreases, and the thermal conductivity decreases. The calcium titanate hollow sphere is very beneficial to reducing the density of the coating and improving light scattering (especially solar reflectance), and the difference in refractive index between the inner and outer layers of the hollow particle can provide multiple scattering paths for sunlight, thereby improving the reflectivity. Comparative Example 3 lacks calcium titanate hollow spheres, so the radiation refrigeration effect of Comparative Example 3 decreases.

[0080] The above description is merely a specific implementation of the present application, but the protection scope of the present application is not limited thereto. It should be understood by those skilled in the art that any changes or replacements within the technical scope disclosed by the present application can be easily conceived by those skilled in the art, and all such changes and replacements fall within the protection scope and disclosure scope of the present application.

Claims

1. A method for preparing a high thermal conductivity, radiation-induced cooling and heat dissipation coating for LED lighting modules, characterized in that, The preparation method includes: S1, add hexagonal boron nitride flake powder to deionized water for dispersion, add dopamine hydrochloride and Tris buffer, add tannic acid and zinc acetate aqueous solution to obtain modified boron nitride flake powder; S2, dispersing lignocellulose powder in deionized water, adding magnesium chloride hexahydrate and sodium silicate nonahydrate sequentially to obtain a slurry, transferring the slurry to a hydrothermal reactor for reaction, filtering and drying the product, then carbonizing it in a nitrogen atmosphere to obtain powder, cooling the powder and adding anhydrous ethanol, adding γ-aminopropyltriethoxysilane to obtain magnesium silicate powder. S3, dissolve calcium nitrate tetrahydrate in deionized water, add citric acid to complex, add tetrabutyl titanate and ytterbium nitrate pentahydrate under ice bath conditions to obtain a gel, dry the gel to dehydrate, pre-calcine and keep warm to obtain calcium titanate balls, disperse the calcium titanate balls in deionized water, add aluminum nitrate nonahydrate, filter, dry and calcine, spray with phosphoric acid solution and solidify to obtain calcium titanate hollow ball powder; S4, methyl phenyl silicone resin, modified boron nitride flake powder, magnesium silicate powder and calcium titanate hollow sphere powder are mixed with γ-glycidoxypropyltriethoxysilane and dipropylene glycol methyl ether, and after degassing, a high thermal conductivity radiation cooling and heat dissipation coating for LED lighting modules is obtained.

2. The method for preparing the high thermal conductivity radiation cooling and heat dissipation coating for LED lighting modules according to claim 1, characterized in that, In S1: The mass ratio of the hexagonal boron nitride flake powder, deionized water, dopamine hydrochloride, Tris buffer, tannic acid and zinc acetate aqueous solution is (100-110): (2000-2200): (1.8-2.2): (1.8-2.2): (1.8-2.2): (193-235).

3. The method for preparing the high thermal conductivity radiation cooling and heat dissipation coating for LED lighting modules according to claim 1, characterized in that, In S1: The zinc acetate aqueous solution has a mass fraction of 6wt.%-8wt.%.

4. The method for preparing the high thermal conductivity radiation cooling and heat dissipation coating for LED lighting modules according to claim 1, characterized in that, In S2: The mass ratio of the lignocellulose powder, magnesium chloride hexahydrate and sodium silicate nonahydrate is (18-22):(54-66):(36-44).

5. The method for preparing the high thermal conductivity radiation cooling and heat dissipation coating for LED lighting modules according to claim 1, characterized in that, In S2: The mass ratio of the powder, anhydrous ethanol and γ-aminopropyltriethoxysilane is 100:(90-100):(1.8-2.2).

6. The method for preparing the high thermal conductivity radiation cooling and heat dissipation coating for LED lighting modules according to claim 1, characterized in that, In S3: The mass ratio of calcium nitrate tetrahydrate, citric acid, tetrabutyl titanate and ytterbium nitrate pentahydrate is (53-65):(104-126):(61-75):(6-8).

7. The method for preparing the high thermal conductivity radiation cooling and heat dissipation coating for LED lighting modules according to claim 1, characterized in that, In S3: The mass ratio of the calcium titanate balls, aluminum nitrate nonahydrate, and phosphoric acid solution is (95-100):(6-8):(0.4-0.6).

8. The method for preparing the high thermal conductivity radiation cooling and heat dissipation coating for LED lighting modules according to claim 1, characterized in that, In S4: The mass ratio of the methylphenyl silicone resin, modified boron nitride flake powder, magnesium silicate powder, calcium titanate hollow sphere powder, γ-glycidoxypropyltriethoxysilane and dipropylene glycol methyl ether is (270-330):(150-185):(200-230):(125-155):(6-8):(80-90).

9. A high thermal conductivity radiation cooling coating for an LED lighting module obtained by the preparation method according to any one of claims 1-8.