An adaptive fish-scale modified rice husk ash radiation-cooling polymer coating, its preparation method and application

Abstract

The application discloses a self-adaptive fish scale modified rice hull ash radiation refrigeration polymer coating as well as a preparation method and application thereof, and belongs to the technical field of coating compositions. The preparation method is high in efficiency and convenient, the raw materials are widely sourced, and the production cost is low, so that high-value utilization of solid waste can be realized. In the obtained fish scale modified rice hull ash radiation refrigeration polymer coating, the raw material fish scale has a fluorescent effect, can stably absorb ultraviolet rays during the day, and the infrared radiation of silicon dioxide in the rice hull ash and the excitation radiation of titanium dioxide in the polymer coating can be combined, so that the radiation effect of the coating under multi-scene illumination is realized, and the refrigeration effect is achieved. The application has a good use prospect in reducing heat input.

Description

Technical Field

[0001] This invention relates to the field of coating composition technology, and in particular to an adaptive fish scale modified rice husk ash radiation cooling polymer coating, its preparation method and application. Background Technology

[0002] To reduce energy consumption and mitigate the harmful effects of strong solar radiation in summer, daytime radiative cooling is a passive radiative cooling method that consumes no energy.

[0003] With the development of the coatings industry, the functions of coatings are becoming increasingly specialized, and the market demand for coatings with special functions is also rising. Radiative cooling refers to a cooling method that directly releases heat into outer space through atmospheric windows via infrared radiation. The characteristic of radiative cooling is that the surface temperature of the cooling element is constantly lower than the air temperature, and then the temperature of the cooling element is lowered below the air temperature through conduction, thus achieving the purpose of radiative cooling. These cooling systems themselves become heat sources. Radiative cooling technology utilizes the spontaneous thermal radiation of materials for cooling, requiring no energy input, making it a low-carbon, environmentally friendly technology with a net cooling effect.

[0004] For example, Chinese invention patent CN111303709A discloses a radiation-cooling coating, its preparation method, and its application. This radiation-cooling coating, by mass percentage, comprises the following raw material components: porous cordierite 4%~8%, titanium dioxide 10%~18%, acrylic resin 22%~35%, silane coupling agent 0.5%~1.5%, film-forming aid 0.1%~1%, leveling agent 0.1%~1%, dispersant 0.1%~1%, defoamer 0.2%~1%, thickener 0.1%~2%, anti-flash rust agent 0.1%~2%, and the balance being dipropylene glycol methyl ether acetate. It is prepared by mixing the above raw materials. This radiation-cooling coating possesses both high solar reflectivity and selective high emissivity within atmospheric windows. Its preparation method is simple, easy to implement, and low-cost. However, this material requires pre-preparation of a gel and high-temperature calcination, making the process relatively complex and energy-intensive. Furthermore, the coating has a large porosity, resulting in poor waterproofing and hindering long-term use.

[0005] Chinese invention patent CN115386273A discloses a daytime radiation cooling coating, composed of a selectively permeable / absorbing polymer and 9-12μm highly selectively radiating silica spheres in a volume ratio of 1:0.01-0.1; wherein the selectively permeable / absorbing polymer is composed of polymethylpentene (TPX) and acrylic resin in a mass ratio of 0.01-0.05:1. This invention's daytime radiation cooling coating has low preparation cost and simple process, exhibits high permeability in the 0.2-2.5μm range, and achieves high infrared absorption in the 8-13μm range through the coupling of polymethylpentene (TPX) and silica microspheres. When coated on substrates of different properties such as highly reflective metals, it can achieve a temperature drop lower than the ambient temperature under high solar radiation during the day, thereby reducing cooling energy consumption and saving significant amounts of energy. However, the coating uses a single type of microparticle, limiting the types of radiation it can absorb. Its effectiveness will be reduced under other solar radiation conditions, and its function requires further optimization.

[0006] Chinese invention patent CN110373072A discloses a radiation self-cooling functional coating and its preparation method. The coating is composed of an 8-14 μm infrared highly selective radiation nano-functional composition and a fluorinated resin. The fluorinated resin solid component accounts for 30%-80% of the total solid component mass of the coating. The 8-14 μm infrared highly selective radiation nano-functional composition is composed of nano-silica, rare earth silicate compounds, and molybdate compounds in a mass ratio of 1:(0.5-2):(0.5-2). The stoichiometric ratio of the rare earth silicate compounds is SiO2. (0.5~2.0)RE2O3 (0.1~1.0)Na₂O; the molybdate compound has the molecular formula RMoO₄. This invention's radiation-induced self-cooling functional coating has a simple preparation process and can be coated onto the surfaces of substrates with different properties, such as metals, plastics, and ceramics, to form a radiation-induced self-cooling functional coating, achieving zero-energy cooling and saving significant energy consumption. While this application solves the technical problem of limited particle types, the formulation of the radiation nanofunctional composition used is more complex, and the different optical properties between particles make selective emission and reflection difficult to adjust to an ideal state, leaving room for improvement in its performance.

[0007] In summary, this invention provides a radiation-cooling polymer coating that is widely available, inexpensive, and easy to prepare. It effectively reduces solar heat input and the radiation effect of the coating under various lighting conditions, thereby achieving a cooling effect and is of great significance in reducing energy consumption. Summary of the Invention

[0008] In view of the above-mentioned deficiencies of the prior art, in a first aspect of the present invention, a method for preparing a fish-scale modified rice husk ash radiation-cooling polymer coating with efficient and convenient process, wide availability of raw materials, and low production cost is provided, comprising the following steps:

[0009] (1) Rice husk ash and fish scales are mixed with organic solvents and ground to obtain modified rice husk ash slurry and fish scale slurry;

[0010] (2) The modified rice husk slurry and fish scale slurry are mixed and ground, a surface activator is added and a mixed slurry is obtained; the organic solvent in the mixed slurry is removed, and the residue is reacted to obtain fish scale modified rice husk ash;

[0011] (3) In the presence of the template agent in the microemulsion solution environment, the fish scale modified rice husk ash forms a tiered structure of fish scale modified rice husk ash under the hydrolysis of titanate ester;

[0012] (4) The fish-scale modified rice husk ash with the stepped structure is mixed with coating additives and styrene-acrylic emulsion to obtain a fish-scale modified rice husk ash radiation cooling polymer coating.

[0013] The inventive concept of this invention lies in the selection of rice husk ash and fish scales, making full use of agricultural and forestry solid waste to achieve the goals of green environmental protection and resource conservation. Combined with liquid-phase grinding, it offers energy-saving advantages. The design concept of choosing fish scales is that the fluorescent substances present in fish scales help consume the energy of natural light irradiation, thereby expanding the range of light source consumption for the coating; at the same time, fish scales are biological waste, and this method also helps to utilize them at a high value. Through grinding in an organic solution, fly ash and fish scales are respectively refined in particle size and have their surface groups modified. The activation energy provided by grinding stimulates the activation sites on fly ash and fish scales, while simultaneously activating solvent molecules, promoting the reaction between solvent molecules and groups on the surface of fly ash and fish scales, optimizing the molecular structure and groups on the surface of fly ash and fish scales. The combination of grinding and modifying rice husk ash slurry and fish scale slurry is a low-consumption and high-efficiency modification method. Furthermore, the short reaction time greatly simplifies the processing and ensures the modification efficiency of the process. In subsequent steps, a microemulsion method was employed to construct a tiered modified material using titanate hydrolysis, which improved the structural stability of the modified material and significantly expanded the hierarchical structure. Simultaneously, the photo-effect of titanate hydrolysis products was utilized to further broaden the material's light absorption and radiation range, enabling the coating to adapt its radiation effect under various lighting conditions. This invention, employing a solid waste recycling approach, explores an effective way to achieve high-value utilization of bio-fertilizers, playing a crucial role in building energy conservation and contributing to building energy saving and carbon reduction.

[0014] Preferably, in step (1) by weight, 3-5 parts of rice husk ash, 1-3 parts of fish scale, and 50 parts of organic solvent are used to prepare modified rice husk ash slurry and fish scale slurry, respectively; in step (2), the amount of modified rice husk ash slurry is 20-40 parts, the amount of fish scale slurry is 20-40 parts, the amount of surfactant is 0.3-0.5 parts, and the amount of organic solvent is 50 parts; in step (3), the amount of template agent is 1-3 parts, the amount of fish scale modified rice husk ash is 4-6 parts, the amount of water is 50 parts, and the amount of titanate is 2-4 parts; in step (4), the amount of fish scale modified rice husk ash with tiered structure is 6-10 parts, the amount of coating additive is 4-12 parts, and the amount of styrene-acrylic emulsion is 20-40 parts.

[0015] During the preparation of the final product, technicians can add appropriate coating additives as needed to optimize the product or processing performance, such as rheology modifiers, dispersants, colorants, stabilizers, etc., which are commonly used in this field.

[0016] More preferably, the coating additives include 1-3 parts rheology modifier, 1-3 parts dispersant, 1-3 parts colorant, and 1-3 parts stabilizer.

[0017] Furthermore, the rheology modifier is at least one of organobentonite and polyamide wax.

[0018] Furthermore, the dispersant is at least one of sodium citrate and sodium tripolyphosphate.

[0019] Furthermore, the colorant is at least one of chitosan oligosaccharide and diethylaminoethanol hexanoate.

[0020] Furthermore, the stabilizer is at least one of didecyl phosphite, hydroxypropyl distarch phosphate, and dibasic lead phosphite.

[0021] Based on the inventive concept of this invention, fish scales can be sourced from a wide variety of sources. Considering the content and type of fluorescent substances and the ease of obtaining biological waste, pinecone, flounder, and sea bream are very suitable fish scale sources for the process of this invention.

[0022] Preferably, in step (1), the source of the fish scales includes at least one of pinecone, flounder, and sea bream.

[0023] Preferably, in step (1), the organic solvent is at least one of polyethylene glycol, ethylene glycol phenyl ether, and dimethyl ester.

[0024] Preferably, in step (1), the grinding time of rice husk ash or fish scales in organic solvent is 30-60 min.

[0025] Preferably, in step (2), the reaction temperature is 160~200℃ and the reaction time is 20~40min.

[0026] Preferably, in step (2), the surfactant is at least one of polyvinyl alcohol, Span, and Tween.

[0027] Preferably, in step (3), the template agent is at least one of phosphate ester and polyvinylpyrrolidone.

[0028] Preferably, in step (3), the hydrolysis time is 30~60 min.

[0029] In a second aspect of the present invention, a fish-scale modified rice husk ash radiation-cooling polymer coating that effectively reduces solar heat input and has radiation effects under various lighting conditions is provided, which is prepared by the method of the first aspect of the present invention.

[0030] In a third aspect of the invention, the application of the fish-scale modified rice husk ash radiation cooling polymer coating of the second aspect of the invention is provided, specifically as an application of radiation cooling coating material in reducing heat input.

[0031] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0032] This invention provides a method for preparing a fish scale-modified rice husk ash radiation cooling polymer coating. The process is efficient and convenient, with a wide range of raw material sources and low production costs, enabling high-value utilization of solid waste. Using fly ash and fish scales as the main raw materials, both derived from low-value waste, the application value of the material is greatly enhanced through recycling and functional optimization. The method employs grinding activation and modification, featuring green and low-carbon process characteristics. Compared with existing chemical modification methods, the process technology is more environmentally friendly and lower in cost.

[0033] This invention provides a fish-scale modified rice husk ash radiation-cooling polymer coating. The fish scales in the coating have a fluorescent effect and stably absorb ultraviolet light during the day. The infrared radiation of silica in rice husk ash and the excitation radiation of titanium dioxide in the polymer coating are combined. By utilizing the radiation effects of different components on different wavelengths of light, the performance of the coating is enriched and the radiation-cooling efficiency of the coating is improved. Through the matching design of different components and different functions, the functions of the coating are coordinated to achieve the best radiation-cooling effect of the coating.

[0034] This invention provides an application of fish-scale modified rice husk ash radiation cooling polymer coating, which has good prospects for reducing heat input; it conforms to the theme of promoting and developing building energy conservation and low carbon emission reduction, has significant economic benefits, and has extremely high technology promotion value. Detailed Implementation

[0035] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0036] Rice husk ash is a commercially available product, composed of 40%~60% silicon dioxide, 1%~2% aluminum oxide, and 5%~10% calcium oxide; fish scales are scales from pinecone, flounder, and sea bream, which are recycled scales that are mechanically crushed into powder for use; other chemical reagents can be purchased on the market.

[0037] Example 1

[0038] The preparation method of fish scale modified rice husk ash radiation cooling polymer coating is as follows:

[0039] (1) Add 50 parts by weight of polyethylene glycol, 5 parts by weight of rice husk ash and 210 parts by weight of agate balls (large balls: medium balls: small balls = 1:3:3) into a ball mill jar, grind with a planetary ball mill at 800 r / min for 30 min, and then sieve the mixture in the jar to obtain modified rice husk ash slurry; similarly, add 3 parts by weight of pine cone fish scales to 50 parts by weight of polyethylene glycol, grind, and then separate to obtain fish scale slurry;

[0040] (2) Mix 40 parts by weight of modified rice husk ash and 20 parts by weight of fish scale slurry and grind them further. Add 0.3 parts by weight of polyvinyl alcohol to obtain a mixed slurry. After centrifugation to remove polyethylene glycol, transfer it to a reaction vessel and prepare fish scale modified rice husk ash at 180°C. The reaction time is 20 min.

[0041] (3) Add 6 parts by weight of fish scale modified rice husk ash and 1 part by weight of phosphate ester to 50 parts by weight of water, and hydrolyze it for 30 minutes with 4 parts by weight of titanate ester to obtain fish scale modified rice husk ash with a tiered structure.

[0042] (4) Mix and disperse 10 parts by weight of fish scale modified rice husk ash with 2 parts by weight of organic bentonite, 2 parts by weight of sodium citrate, 2 parts by weight of chitosan oligosaccharide, 2 parts by weight of didecyl phosphite and 30 parts by weight of styrene-acrylic emulsion to obtain fish scale modified rice husk ash radiation cooling polymer coating.

[0043] Example 2

[0044] The preparation method of fish scale modified rice husk ash radiation cooling polymer coating is as follows:

[0045] (1) Add 50 parts by weight of polyethylene glycol, 3 parts by weight of rice husk ash and 210 parts by weight of agate balls (large balls: medium balls: small balls = 1:3:3) into a ball mill jar, grind with a planetary ball mill at 800 r / min for 30 min, and then sieve the mixture in the jar to obtain modified rice husk ash slurry; similarly, add 1 part by weight of halibut scales to 50 parts by weight of polyethylene glycol, grind, and separate to obtain fish scale slurry;

[0046] (2) Mix 20 parts by weight of modified rice husk ash and 40 parts by weight of fish scale slurry and grind them further. Add 0.5 parts by weight of Span to obtain a mixed slurry. After centrifugation to remove polyethylene glycol, transfer it to a reaction vessel and prepare fish scale modified rice husk ash at 160°C. The reaction time is 20 min.

[0047] (3) Add 4 parts by weight of fish scale modified rice husk ash and 1 part by weight of polyvinylpyrrolidone to 50 parts by weight of water, and then perform a hydrolysis reaction of 3 parts by weight of titanate for 35 minutes to obtain fish scale modified rice husk ash with a tiered structure.

[0048] (4) Mix and disperse 6 parts by weight of fish scale modified rice husk ash with 1 part by weight of polyamide wax, 1 part by weight of sodium tripolyphosphate, 1 part by weight of diethylaminoethanol hexanoate, 1 part by weight of hydroxypropyl distarch phosphate and 20 parts by weight of styrene-acrylic emulsion to obtain fish scale modified rice husk ash radiation cooling polymer coating.

[0049] Example 3

[0050] The preparation method of fish scale modified rice husk ash radiation cooling polymer coating is as follows:

[0051] (1) Add 50 parts by weight of polyethylene glycol, 4 parts by weight of rice husk ash and 210 parts by weight of agate balls (large balls: medium balls: small balls = 1:3:3) into a ball mill jar, grind with a planetary ball mill at 800 r / min for 60 min, and then sieve the mixture in the jar to obtain modified rice husk ash slurry; similarly, add 1 part by weight of sea bream scales to 50 parts by weight of polyethylene glycol, grind, and separate to obtain fish scale slurry;

[0052] (2) The modified rice husk ash and fish scale slurry were mixed and ground further. 0.4 parts by weight of Tween were added to obtain a mixed slurry. After removing the polyethylene glycol by centrifugation, the mixture was transferred to a reaction vessel and fish scale modified rice husk ash was prepared at 200°C. The reaction time was 40 min.

[0053] (3) Add 5 parts by weight of fish scale modified rice husk ash and 2 parts by weight of phosphate ester to 50 parts by weight of water, and hydrolyze 2 parts by weight of titanate ester for 35 min to obtain fish scale modified rice husk ash with a tiered structure.

[0054] (4) Mix and disperse 7 parts by weight of fish scale modified rice husk ash with 3 parts by weight of organic bentonite, 3 parts by weight of sodium citrate, 3 parts by weight of chitosan oligosaccharide, 3 parts by weight of dibasic lead phosphite and 40 parts by weight of styrene-acrylic emulsion to obtain fish scale modified rice husk ash radiation cooling polymer coating.

[0055] Example 4

[0056] The preparation method of fish scale modified rice husk ash radiation cooling polymer coating is as follows:

[0057] (1) Add 50 parts by weight of ethylene glycol phenyl ether, 4 parts by weight of rice husk ash and 210 parts by weight of agate balls (large balls: medium balls: small balls = 1:3:3) to a ball mill jar, grind with a planetary ball mill at 800 r / min for 30 min, and then sieve the mixture in the jar to obtain modified rice husk ash slurry; similarly, add 2 parts by weight of halibut scales to 50 parts by weight of ethylene glycol phenyl ether, grind, and then separate to obtain fish scale slurry;

[0058] (2) The modified rice husk ash and fish scale slurry were mixed and ground further. 0.5 parts by weight of Span were added to obtain a mixed slurry. After centrifugation to remove ethylene glycol phenyl ether, the mixture was transferred to a reaction vessel and fish scale modified rice husk ash was prepared at 190°C. The reaction time was 20 min.

[0059] (3) Add 6 parts by weight of fish scale modified rice husk ash and 3 parts by weight of polyvinylpyrrolidone to 50 parts by weight of water, and then perform a hydrolysis reaction of 2 parts by weight of titanate for 40 min to obtain fish scale modified rice husk ash with a tiered structure.

[0060] (4) Mix and disperse 6 parts by weight of fish scale modified rice husk ash with 3 parts by weight of organic bentonite, 3 parts by weight of sodium citrate, 3 parts by weight of chitosan oligosaccharide, 3 parts by weight of dibasic lead phosphite and 40 parts by weight of styrene-acrylic emulsion to obtain fish scale modified rice husk ash radiation cooling polymer coating.

[0061] Example 5

[0062] The preparation method of fish scale modified rice husk ash radiation cooling polymer coating is as follows:

[0063] (1) Add 50 parts by weight of diformate, 4 parts by weight of rice husk ash and 210 parts by weight of agate balls (large balls: medium balls: small balls = 1:3:3) into a ball mill jar, grind with a planetary ball mill at 800 r / min for 30 min, and then sieve the mixture in the jar to obtain modified rice husk ash slurry; similarly, add 3 parts by weight of halibut scales to 50 parts by weight of diformate, grind, and then separate to obtain fish scale slurry;

[0064] (2) The modified rice husk ash and fish scale slurry were mixed and ground further. 0.5 parts by weight of Tween were added to obtain a mixed slurry. After centrifugation to remove the dimethyl ester, the slurry was transferred to a reaction vessel and fish scale modified rice husk ash was prepared at 160°C. The reaction time was 30 min.

[0065] (3) Add 4 parts by weight of fish scale modified rice husk ash and 3 parts by weight of polyvinylpyrrolidone to 50 parts by weight of water, and hydrolyze it for 40 minutes with 2 parts by weight of titanate to obtain fish scale modified rice husk ash with a tiered structure.

[0066] (4) Mix and disperse 6 parts by weight of fish scale modified rice husk ash with 3 parts by weight of organic bentonite, 3 parts by weight of sodium citrate, 3 parts by weight of chitosan oligosaccharide, 3 parts by weight of dibasic lead phosphite and 40 parts by weight of styrene-acrylic emulsion to obtain fish scale modified rice husk ash radiation cooling polymer coating.

[0067] Comparative Example 1

[0068] The preparation method of modified rice husk ash radiation-cooling polymer coating includes the following steps:

[0069] (1) Add 50 parts by weight of polyethylene glycol, 4 parts by weight of rice husk ash and 210 parts by weight of agate balls (large balls: medium balls: small balls = 1:3:3) into a ball mill jar, grind for 30 minutes at 800 r / min using a planetary ball mill, and then sieve the mixture in the jar to obtain modified rice husk ash slurry.

[0070] (2) Add 0.4 parts by weight of polyvinyl alcohol to the modified rice husk ash slurry to obtain the slurry. After centrifugation to remove the polyethylene glycol, transfer it to the reactor and prepare the composite modified rice husk ash at 180°C.

[0071] (3) Add 5 parts by weight of composite modified rice husk ash and 2 parts by weight of phosphate ester to 50 parts by weight of water, and obtain titanium dioxide modified rice husk ash by hydrolysis reaction of 2 parts by weight of titanate ester for 50 min.

[0072] (4) Titanium dioxide modified rice husk ash is mixed and dispersed with 2 parts by weight of organic bentonite, 2 parts by weight of sodium citrate, 2 parts by weight of chitosan oligosaccharide, 2 parts by weight of dibasic lead phosphite and 30 parts by weight of styrene-acrylic emulsion to obtain modified rice husk ash radiation cooling polymer coating.

[0073] Comparative Example 2

[0074] The preparation method of fish scale radiation-cooled polymer coating is as follows:

[0075] (1) Add 50 parts by weight of polyethylene glycol, 0.5 parts by weight of halibut scales and 210 parts by weight of agate balls (large balls: medium balls: small balls = 1:3:3) into a ball mill jar, grind with a planetary ball mill at 800 r / min for 30 min, and then sieve the mixture in the jar to obtain fish scale slurry;

[0076] (2) Add 0.4 parts by weight of polyvinyl alcohol to the fish scale slurry to obtain a mixed slurry. After centrifugation to remove the polyethylene glycol, transfer it to a reaction vessel and prepare composite modified fish scales at 180°C.

[0077] (3) Add 5 parts by weight of composite modified fish scales and 2 parts by weight of phosphate ester to 50 parts by weight of water, and obtain titanium dioxide modified fish scales by hydrolysis reaction of 2 parts by weight of titanate ester for 60 min.

[0078] (4) Titanium dioxide modified fish scales are mixed and dispersed with 2 parts by weight of organic bentonite, 2 parts by weight of sodium citrate, 2 parts by weight of chitosan oligosaccharide, 2 parts by weight of dibasic lead phosphite and 30 parts by weight of styrene-acrylic emulsion to obtain fish scale radiation cooling polymer coating.

[0079] Comparative Example 3

[0080] (1) Add 50 parts by weight of polyethylene glycol, 5 parts by weight of rice husk ash and 210 parts by weight of agate balls (large balls: medium balls: small balls = 1:3:3) to a ball mill jar, grind with a planetary ball mill at 800 r / min for 30 min, and then sieve the mixture in the jar to obtain modified rice husk ash slurry; similarly, add 3 parts by weight of halibut scales to 50 parts by weight of polyethylene glycol, grind, and separate to obtain fish scale slurry; the grinding time is 30 min;

[0081] (2) Mix 40 parts by weight of modified rice husk ash and 20 parts by weight of fish scale slurry and grind them further. Add 0.3 parts by weight of polyvinyl alcohol to obtain a mixed slurry. After centrifugation to remove polyethylene glycol, transfer it to a reaction vessel and prepare fish scale modified rice husk ash at 180°C. The reaction time is 20 min.

[0082] (3) Add 5 parts by weight of fish scale modified rice husk ash and 2 parts by weight of phosphate ester to 50 parts by weight of water to obtain fish scale modified rice husk ash with a tiered structure.

[0083] (4) Mix and disperse 8 parts by weight of fish scale modified rice husk ash with 1 part by weight of organic bentonite, 1 part by weight of sodium citrate, 1 part by weight of chitosan oligosaccharide, 1 part by weight of didecyl phosphite and 30 parts by weight of styrene-acrylic emulsion to obtain fish scale modified rice husk ash radiation cooling polymer coating.

[0084] The performance of the coatings in the examples and comparative examples was tested, including mid-infrared solar absorptivity and temperature difference with the surrounding environment. The infrared solar absorptivity was characterized by Fourier transform infrared spectrometer, and the temperature difference with the surrounding environment was measured by infrared thermal imager. The test results are shown in Table 1.

[0085] Table 1:

[0086]

[0087] Data shows that, compared with Examples 1 to 5, Example 1 has the best effect, exhibiting the highest mid-infrared solar absorptivity and the largest temperature difference with the surrounding environment. This is because the coating has constructed a multi-level structure in the coating process, which absorbs and radiates sunlight of multiple wavelengths, thus exhibiting a good radiative cooling effect.

[0088] Compared with Example 1, Example 2 showed poor performance. When preparing fish scale modified rice husk ash, the amount of fish scale added was too high, which would affect the final radiation cooling effect. This is because the main component of rice husk ash has a better radiation effect on sunlight than the fluorescent component in fish scale.

[0089] Compared with Example 1, Example 3 showed poor performance. The amount of titanate added was too small, and the reaction temperature was too high, which affected the control of the ladder structure and failed to achieve the well-designed radiation effect.

[0090] Compared with Example 1, Example 4 performed poorly. The reaction temperature was too high, the rice husk ash was not well activated in the solvent, and the reaction with the fish scale component was poor. Ultimately, this affected the composition and structural design of the coating and failed to achieve a good radiative cooling effect.

[0091] Compared with Example 1, Example 5 showed poor performance because Tween could not fully exert the role of surfactant in dimethyl ester, which affected the preparation and structure of fish scale modified rice husk ash, and ultimately failed to achieve a good radiative cooling effect.

[0092] Compared with Example 1, Comparative Example 1 performed poorly, lacking fish scale components and unable to complete the fish scale modified rice husk ash design with a tiered structure. During the coating process, the absorption of infrared rays in sunlight was weakened, and the heat conduction channels in the coating increased, resulting in a decrease in the temperature difference with the surroundings.

[0093] Compared with Example 1, Comparative Example 2 performed poorly. It lacked rice husk ash, and the addition of fish scale and titanium dioxide to the coating prevented the formation of a tiered structure. Furthermore, the infrared absorption was greatly reduced, while the heat conduction was increased, resulting in a decrease in the temperature difference with the surrounding environment.

[0094] Compared with Example 1, Comparative Example 3 performed poorly. The lack of titanium dioxide in the coating reduced the coating's reflection and radiation of sunlight, weakened infrared absorption, and resulted in a smaller temperature difference with the surrounding environment.

[0095] Based on the analysis of the examples and comparative examples, the grinding and combination of modified rice husk ash and fish scale slurry facilitates low-consumption and high-efficiency modification. By utilizing the hydrolysis of titanate esters to form titanium dioxide, a tiered structure of the modifier is ultimately constructed. During coating application, this expands the light absorption and radiation range of the material and optimizes the radiative cooling effect of the coating.

[0096] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for preparing a fish scale modified rice husk ash radiation refrigeration polymer coating, characterized by, It comprises the following steps: (1) rice husk ash, fish scales are mixed with organic solvents respectively to be ground to obtain modified rice husk ash slurry, fish scale slurry; the organic solvent is at least one of polyethylene glycol, ethylene glycol phenyl ether; (2) the modified rice husk ash slurry and fish scale slurry are mixed and ground, a surface active agent is added and a mixed slurry is obtained; the organic solvent in the mixed slurry is removed, and the remaining material is reacted to obtain fish scale modified rice husk ash; the surface active agent is at least one of polyvinyl alcohol, span, tween; (3) in the presence of a microemulsion solution environment of a template agent, the fish scale modified rice husk ash forms a hierarchical structure of fish scale modified rice husk ash under the hydrolysis of titanate; the template agent is polyvinylpyrrolidone; (4) the hierarchical structure of fish scale modified rice husk ash is mixed with a coating additive and a styrene-acrylic emulsion to obtain a fish scale modified rice husk ash radiation refrigeration polymer coating.

2. The method of claim 1, wherein: In step (1), 3-5 parts of rice husk ash, 1-3 parts of fish scales and 50 parts of organic solvent are used to prepare modified rice husk ash slurry and fish scale slurry; in step (2), the amount of modified rice husk ash slurry is 20-40 parts, the amount of fish scale slurry is 20-40 parts, the amount of surface active agent is 0.3-0.5 parts, and the amount of organic solvent is 50 parts; in step (3), the amount of template agent is 1-3 parts, the amount of fish scale modified rice husk ash is 4-6 parts, the amount of water is 50 parts, and the amount of titanate is 2-4 parts; in step (4), the amount of hierarchical structure of fish scale modified rice husk ash is 6-10 parts, the amount of coating additive is 4-12 parts, and the amount of styrene-acrylic emulsion is 20-40 parts.

3. The method of claim 2, wherein: The coating additive comprises 1-3 parts of rheological agent, 1-3 parts of dispersant, 1-3 parts of colorant and 1-3 parts of stabilizer.

4. The method of claim 3, wherein: The rheological agent is at least one of organic bentonite and polyamide wax; the dispersant is at least one of sodium citrate and sodium tripolyphosphate; the stabilizer is at least one of didecyl phosphite, hydroxypropyl distarch phosphate and lead bisphosphite.

5. The method of claim 1, wherein: In step (1), the source of fish scales includes at least one of pine ball fish, flatfish and sea bream; the grinding time of rice husk ash or fish scales in organic solvents is 30-60 min.

6. The method of claim 1, wherein: In step (2), the reaction temperature is 160-200℃, and the reaction time is 20-40 min.

7. The method of claim 1, wherein: In step (3), the hydrolysis time is 30-60 min.

8. A fish scale modified rice husk ash radiation refrigeration polymer coating characterized by: It is made by the method of any one of claims 1-7.

9. Use of fish scale modified rice husk ash radiation refrigeration polymer coating as claimed in claim 8, wherein the said fish scale modified rice husk ash radiation refrigeration polymer coating is prepared by the process as claimed in claim 1 to 8. It is used as a radiation refrigeration coating material to reduce heat input.

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