Aqueous radiative cooling coating, coating and method of making the same

Abstract

The present application provides a kind of aqueous radiative cooling coating, coating and its preparation method, wherein the raw material of the coating includes inorganic filler, and the inorganic filler includes mesoporous material, metal oxide and carbonate.The coating provided by the present application can effectively reflect sunlight and can effectively passively radiate heat, thereby achieving the effect of cooling and energy saving.

Description

Technical Field

[0001] This invention relates to the field of radiative cooling materials, specifically to a water-based radiative cooling coating, a coating layer, and a method for preparing the same. Background Technology

[0002] Currently, due to the generally low refractive index of the functional materials used in radiative cooling coatings, it remains difficult to achieve high contrast ratio, high reflectivity, and high emissivity in single-layer radiative cooling coatings in research on their overall performance. Furthermore, the insufficient overall performance of these coatings fails to meet practical application requirements. Double-layer coating systems can achieve higher solar reflectivity and atmospheric window emissivity, while also improving the coating's contrast ratio and other overall performance. However, double-layer systems can cause inconvenience in production and construction, hindering the application and promotion of water-based radiative cooling coatings. Therefore, finding more effective materials to maintain a strong radiative cooling effect while improving the overall performance of the coating, ultimately developing single-layer water-based radiative cooling coatings with high contrast ratios, is an important development direction for this type of coating.

[0003] Therefore, research is urgently needed on how to obtain coatings with stronger overall performance and better radiative cooling properties. Summary of the Invention

[0004] The purpose of this invention is to provide a water-based radiative cooling coating, coating material and its preparation method, so as to improve the reflection effect of sunlight and thus achieve the purpose of cooling.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A water-based radiative cooling coating, wherein the raw materials of the coating include inorganic fillers;

[0007] The inorganic filler includes mesoporous materials, metal oxides, and carbonates.

[0008] In some embodiments of the present invention, the mesoporous material is mesoporous zirconium hydrogen phosphate, preferably plate-like mesoporous zirconium hydrogen phosphate, and more preferably plate-like mesoporous zirconium hydrogen phosphate with a particle size of 0.5 to 0.8 μm.

[0009] In some embodiments of the present invention, the metal oxide is at least one of aluminum oxide, zirconium oxide, and magnesium oxide, and / or the carbonate is at least one of calcium carbonate, strontium carbonate, magnesium carbonate, and aluminum carbonate;

[0010] Preferably, the alumina is spherical alumina;

[0011] Preferably, the alumina has a particle size of 0.8–1.0 μm;

[0012] Preferably, the calcium carbonate is spherical calcium carbonate;

[0013] Preferably, the calcium carbonate has a particle size of 0.5–0.8 μm.

[0014] Some embodiments of the present invention have at least one of the following features:

[0015] The raw materials of the coating also include a thickener, preferably the content of the thickener is 0.01 to 0.10 wt.% of the total mass of the coating, preferably the thickener is at least one of cellulose ether, cellulose ether derivatives, polyurethane, and inorganic thickener;

[0016] The raw materials of the coating also include a neutralizing agent, preferably the content of the neutralizing agent is 0.20 to 1.00 wt.% of the total mass of the coating, and preferably the neutralizing agent is at least one of organic amine neutralizing agents and inorganic alkali neutralizing agents;

[0017] The raw materials of the coating also include a dispersant, preferably the content of the dispersant is 1.00 to 3.00 wt.% of the total mass of the coating, and preferably the dispersant is at least one of polycarboxylate type dispersant and polyether type dispersant;

[0018] The raw materials of the coating also include a defoamer, preferably the content of the defoamer is 0.20 to 1.00 wt.% of the total mass of the coating, and preferably the defoamer is at least one of organosilicon defoamer and mineral oil defoamer;

[0019] The raw materials of the coating also include water-based resin. Preferably, the content of the water-based resin is 25.0 to 30.0 wt.% of the total mass of the coating. Preferably, the water-based resin is at least one of acrylate copolymer emulsion, silicone emulsion, and fluorocarbon emulsion. More preferably, the viscosity of the acrylate copolymer emulsion is 300 to 1000 mPa·s.

[0020] The raw materials of the coating also include film-forming aids. Preferably, the content of the film-forming aids is 1.00 to 5.00 wt.% of the total mass of the coating. Preferably, the film-forming aids are at least one of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, diisobutyl succinate, and dipropylene glycol butyl ether.

[0021] The raw materials of the coating also include a bactericide, preferably the content of the bactericide is 1.00 to 3.00 wt.% of the total mass of the coating, preferably the bactericide is at least one of organosulfur bactericides, organobromine bactericides, quaternary ammonium salt bactericides, and isothiazolinone bactericides;

[0022] The raw materials of the coating also include water, preferably with a water content of 25.0 to 45.0 wt.% of the total mass of the coating.

[0023] To achieve the above objectives, the present invention also provides the following technical solutions:

[0024] A method for preparing the above-mentioned water-based radiative cooling coating, the method comprising the following steps:

[0025] S1, add water, thickener, neutralizer, dispersant and defoamer into the dispersion tank;

[0026] S2, Inorganic filler is added to the dispersion cylinder;

[0027] S3, mix the water-based resin, film-forming aid, bactericide and the material obtained in step S2, and disperse them in the dispersion tank to obtain the water-based radiative cooling coating.

[0028] In some embodiments of the present invention, step S1 has at least one of the following features:

[0029] The mass ratio of water, thickener, neutralizer, dispersant, and defoamer is (500-650):(0.5-2.0):(5-10):(10-20):(10-20);

[0030] Add the water, thickener, neutralizer, dispersant, and defoamer at a rotation speed of 500–800 rpm;

[0031] The dispersion time of the water, thickener, neutralizer, dispersant, and defoamer in the dispersion tank is 0.2 to 0.5 hours.

[0032] The temperature inside the dispersion tank is (5~10℃)~(40~55℃).

[0033] In some embodiments of the present invention, step S2 has at least one of the following features:

[0034] The mass ratio of the inorganic filler to the material obtained in step S1 is (4.0-4.5):(2.0-3.5);

[0035] The dispersion cylinder rotates at 1500–2500 rpm, and the dispersion time is 0.5–1.0 h.

[0036] The temperature inside the dispersion tank is 5–55°C.

[0037] In some embodiments of the present invention, step S3 has at least one of the following features:

[0038] The mass ratio of the aqueous resin, film-forming aid, bactericide, and material obtained in step S2 is (20-25):(1.2-1.8):(0.5-1.0).

[0039] The dispersion cylinder rotates at 500–800 rpm, and the dispersion time is 0.2–0.5 h.

[0040] The temperature inside the dispersion tank is 5–40°C.

[0041] To achieve the above objectives, the present invention also provides the following technical solutions:

[0042] A coating, said coating being made from an aqueous radiative cooling coating as described above, or from an aqueous radiative cooling coating obtained by the method described above;

[0043] The reflectivity of the coating is greater than or equal to 94%, preferably greater than or equal to 94.15%.

[0044] To achieve the above objectives, the present invention also provides the following technical solutions:

[0045] A method for preparing the above-mentioned coating involves applying the above-mentioned water-based radiative cooling coating or the water-based radiative cooling coating obtained by the above method to the surface of a substrate, and then drying it to obtain the coating.

[0046] Other applicable areas will become apparent from the description provided in this disclosure.

[0047] The descriptions and specific examples in the invention summary are intended to be illustrative only and are not intended to limit the scope of this disclosure.

[0048] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0049] 1. The coating provided by this invention has a high reflectivity to sunlight, thereby achieving a significant cooling effect;

[0050] 2. This invention uses sheet-like mesoporous zirconium hydrogen phosphate and metal oxide as a radiative cooling coating. It can achieve high solar reflectivity and atmospheric window emissivity without the need for multiple coatings or ultra-high pigment volume concentration (PVC) of the coating, thereby obtaining excellent cooling effect.

[0051] 3. The single-layer radiative cooling coating prepared by this invention has excellent comprehensive performance, which is better than the requirements of the superior grade of GB / T9755-2024 "Synthetic Resin Emulsion Wall Coatings", and breaks through the current standard value performance of single-layer radiative cooling coatings. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other solutions can be obtained based on these drawings without creative effort.

[0053] Figure 1 The graph shows the test data obtained from the self-testing device provided in a specific embodiment of the present invention. Detailed Implementation

[0054] 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. It should be understood that the specific embodiments described herein are only for illustration and explanation of the present invention and are not intended to limit the present invention.

[0055] Any specific numerical values ​​disclosed herein (including the endpoints of numerical ranges) are not limited to their exact values, but should be understood to also include values ​​close to the exact value, such as all possible values ​​within ±5% of the exact value. Furthermore, with respect to the disclosed numerical ranges, one or more new numerical ranges can be obtained by arbitrarily combining the endpoint values ​​of the range, the endpoint values ​​with specific point values ​​within the range, and the specific point values ​​themselves; these new numerical ranges should also be considered as specifically disclosed herein.

[0056] The terminology used in this disclosure is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” as used in this disclosure are intended to include the plural forms as well. The terms “comprising,” “including,” “containing,” and “having” are inclusive and thus describe the presence of said features, elements, compositions, steps, integers, operations, and / or components, but do not exclude the presence or inclusion of one or more other features, integers, steps, operations, elements, components, and / or sets thereof. Although the open-ended term “comprising” should be understood as a non-limiting term used to describe and claim the various embodiments described in this disclosure, in some aspects it may instead be understood as a more restrictive and limiting term, such as “consisting of” or “substantially consisting of.” Thus, for any given embodiment describing a composition, material, component, element, feature, integer, operation, and / or process step, this disclosure also particularly includes embodiments consisting of or substantially consisting of such compositions, materials, components, elements, features, integers, operations, and / or process steps. In the case of “consisting of…”, the alternative embodiments exclude any additional compositions, materials, components, elements, features, integers, operations and / or process steps. In the case of “essentially composed of…”, any additional compositions, materials, components, elements, features, integers, operations and / or process steps that substantially affect the essential and novel characteristics are excluded from such embodiments. However, any compositions, materials, components, elements, features, integers, operations and / or process steps that do not substantially affect the essential and novel characteristics may be included in the embodiments.

[0057] Any method steps, processes, and operations described in this disclosure should not be construed as necessarily requiring them to be performed in a particular order as discussed or shown, unless explicitly specified. It should also be understood that additional or alternative steps may be used unless otherwise stated.

[0058] In this application, except where expressly stated, any matters or issues not mentioned are directly applicable to those known in the art without any modification. Furthermore, any implementation described in this disclosure may be freely combined with one or more other implementations described in this disclosure, and the resulting technical solutions or concepts shall be considered part of the original disclosure or original record of this application, and should not be regarded as new content not disclosed or anticipated in this disclosure, unless those skilled in the art consider the combination to be clearly unreasonable.

[0059] Unless otherwise stated, the terms used herein have the same meaning as commonly understood by those skilled in the art, and if a term is defined herein and its definition differs from the common understanding in the art, the definition herein shall prevail.

[0060] Unless otherwise stated, when % is mentioned in this document, it means wt.%.

[0061] Existing radiation cooling coatings still have low solar reflectivity, and there is an urgent need for a coating or coating material that can effectively reflect sunlight and has a significant cooling effect. In view of this, the present invention proposes the following technical solution.

[0062] First aspect

[0063] This invention provides an aqueous radiative cooling coating, wherein the raw materials of the coating include inorganic fillers; wherein the inorganic fillers include mesoporous materials, metal oxides and carbonates.

[0064] It is worth noting that in existing technologies, when common metal oxides and rare earth materials are used as fillers in radiative cooling coatings, the overall performance of the resulting coatings still fails to meet increasingly stringent usage requirements. For example, existing radiative cooling coatings still suffer from drawbacks such as poor scrub resistance and low contrast ratio. Therefore, this invention uses a composite of mesoporous materials, metal oxides, and carbonates as fillers to prepare the aforementioned radiative cooling coating and the coating made from this filler. This invention aims to utilize the reflective radiation properties of mesoporous materials, metal oxides, and carbonates to enhance the reflectivity of sunlight and the emissivity of atmospheric windows.

[0065] In some embodiments of the present invention, the mesoporous material is mesoporous zirconium hydrogen phosphate, preferably plate-shaped mesoporous zirconium hydrogen phosphate, and more preferably plate-shaped mesoporous zirconium hydrogen phosphate with a particle size of 0.5 to 0.8 μm.

[0066] It is worth noting that mesoporous zirconium hydrogen phosphate, especially lamellar mesoporous zirconium hydrogen phosphate, and even more particularly lamellar mesoporous zirconium hydrogen phosphate with a particle size of 0.5–0.8 μm, has an optical band gap wider than that of the sun. Therefore, it can be used as a radiation cooling material to improve the solar reflectivity and emissivity of coatings and coatings made from such coatings. Moreover, due to the morphological characteristics of its mesoporous structure, mesoporous zirconium hydrogen phosphate can cause sunlight to be scattered multiple times in its pores, thereby further enhancing the reflective radiation effect of coatings made from such coatings. Furthermore, lamellar mesoporous zirconium hydrogen phosphate has a larger specific surface area. After the lamellar mesoporous zirconium hydrogen phosphate with a larger specific surface area spreads on the surface of the coated substrate, it can provide the coating made from such coatings with excellent contrast ratio and service resistance.

[0067] In some embodiments of the present invention, the metal oxide is at least one of aluminum oxide, zirconium oxide, and magnesium oxide.

[0068] In some embodiments of the present invention, the carbonate is at least one selected from calcium carbonate, strontium carbonate, magnesium carbonate, and aluminum carbonate.

[0069] In some embodiments of the present invention, the alumina is spherical alumina.

[0070] In some embodiments of the present invention, the particle size of the alumina is 0.8 to 1.0 μm. Exemplarily, it can be any value selected from 0.85 μm, 0.9 μm, or 0.95 μm, or any value within a range consisting of any two of these values.

[0071] In some embodiments of the present invention, the calcium carbonate is spherical calcium carbonate.

[0072] In some embodiments of the present invention, the particle size of the calcium carbonate is 0.5 to 0.8 μm. Exemplarily, it can be any value selected from 0.55 μm, 0.6 μm, 0.65 μm, 0.7 μm, or 0.75 μm, or any value within the range formed by any two of these values.

[0073] It is worth noting that in some embodiments of the present invention, spherical alumina and spherical calcium carbonate are used together as fillers. The reflective radiation characteristics of spherical alumina and spherical calcium carbonate are utilized to enhance the reflectivity of sunlight and the emissivity of atmospheric windows, thereby making the coating made from the coating material have better reflective radiation effect and better cooling effect.

[0074] Furthermore, in some embodiments of the present invention, spherical alumina with a particle size of 0.8 to 1.0 μm and spherical calcium carbonate with a particle size of 0.5 to 0.8 μm are used together as fillers. The unique reflective radiation characteristics of spherical alumina and spherical calcium carbonate within this particle size range are utilized to further enhance the solar reflectivity and atmospheric window emissivity, thereby making the coating obtained from the coating material have better reflective radiation effect and better cooling effect.

[0075] In some embodiments of the present invention, the raw materials of the coating also include a thickener.

[0076] In some embodiments of the present invention, the content of the thickener is 0.01 to 0.10 wt.% of the total mass of the coating. For example, it can be any one of 0.02 wt.%, 0.03 wt.%, 0.04 wt.%, 0.05 wt.%, 0.06 wt.%, 0.07 wt.%, 0.08 wt.%, or 0.09 wt.%, or any one of any two of these values.

[0077] In some embodiments of the present invention, the thickener is at least one of cellulose ether, cellulose ether derivatives, polyurethane, and inorganic thickener.

[0078] In some embodiments of the present invention, the raw materials of the coating also include a neutralizing agent.

[0079] In some embodiments of the present invention, the content of the neutralizing agent is 0.20 to 1.00 wt.% of the total mass of the coating. Exemplarily, it can be any one of 0.3 wt.%, 0.4 wt.%, 0.5 wt.%, 0.6 wt.%, 0.7 wt.%, 0.07 wt.%, 0.8 wt.%, or 0.9 wt.%, or any one of any two of these values.

[0080] In some embodiments of the present invention, the neutralizing agent is at least one of organic amine neutralizing agents and inorganic base neutralizing agents.

[0081] In some embodiments of the present invention, the raw materials of the coating also include a dispersant.

[0082] In some embodiments of the present invention, the content of the dispersant is 1.00 to 3.00 wt.% of the total mass of the coating. Exemplarily, it can be any one of 1.2 wt.%, 1.5 wt.%, 1.7 wt.%, 1.9 wt.%, 2 wt.%, 2.3 wt.%, 2.5 wt.%, or 2.7 wt.%, or any one of any two of these values.

[0083] In some embodiments of the present invention, the dispersant is at least one of a polycarboxylate dispersant and a polyether dispersant.

[0084] In some embodiments of the present invention, the raw materials of the coating also include a defoamer.

[0085] In some embodiments of the present invention, the content of the defoamer is 0.20 to 1.00 wt.% of the total mass of the coating. Exemplarily, it can be any one of 0.25 wt.%, 0.3 wt.%, 0.4 wt.%, 0.5 wt.%, 0.6 wt.%, 0.7 wt.%, 0.8 wt.%, or 0.9 wt.%, or any one of any two of these values.

[0086] In some embodiments of the present invention, the defoamer is at least one of silicone defoamers and mineral oil defoamers.

[0087] In some embodiments of the present invention, the raw materials of the coating also include water-based resin.

[0088] In some embodiments of the present invention, the content of the water-based resin is 25.0 to 30.0 wt.% of the total mass of the coating. For example, it can be any one of 26 wt.%, 27 wt.%, 28 wt.%, 29 wt.%, or 29.5 wt.%, or any one of any two of these values.

[0089] In some embodiments of the present invention, the aqueous resin is at least one of acrylate copolymer emulsion, silicone emulsion, and fluorocarbon emulsion.

[0090] In some embodiments of the present invention, the viscosity of the acrylate copolymer emulsion is 300–1000 mPa·s. Exemplarily, it can be any value from 400 mPa·s, 500 mPa·s, 600 mPa·s, 700 mPa·s, 800 mPa·s, or 900 mPa·s, or any value within a range consisting of any two of these values.

[0091] In some embodiments of the present invention, the raw materials of the coating also include film-forming aids.

[0092] In some embodiments of the present invention, the content of the film-forming aid is 1.00 to 5.00 wt.% of the total mass of the coating. For example, it can be any one of 2 wt.%, 3 wt.%, or 4 wt.%, or any one of any two of these values ​​within a range.

[0093] In some embodiments of the present invention, the film-forming aid is at least one selected from 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, diisobutyl succinate, and dipropylene glycol butyl ether.

[0094] In some embodiments of the present invention, the raw materials of the coating also include a bactericide.

[0095] In some embodiments of the present invention, the content of the bactericide is 1.00 to 3.00 wt.% of the total mass of the coating. For example, it can be any one of 2 wt.%, 2.3 wt.%, or 2.5 wt.%, or any one of any two of these values.

[0096] In some embodiments of the present invention, the bactericide is at least one of organosulfur bactericides, organobromine bactericides, quaternary ammonium salt bactericides, and isothiazolinone bactericides.

[0097] In some embodiments of the present invention, the raw materials of the coating also include water.

[0098] In some embodiments of the present invention, the water content is 25.0 to 45.0 wt.% of the total mass of the coating. For example, it can be any one of 29 wt.%, 30 wt.%, or 40 wt.%, or any one of any two of these values.

[0099] In some embodiments of the present invention, deionized water is used.

[0100] Second aspect

[0101] This invention provides a method for preparing the above-mentioned water-based radiative cooling coating, the method comprising the following steps: S1, adding water, thickener, neutralizer, dispersant and defoamer into a dispersion tank; S2, adding inorganic filler into the dispersion tank; S3, mixing water-based resin, film-forming aid, bactericide and the material obtained in step S2, dispersing in the dispersion tank to obtain the water-based radiative cooling coating.

[0102] In some embodiments of the present invention, in step S1, the mass ratio of water, thickener, neutralizer, dispersant and defoamer is (500-650):(0.5-2.0):(5-10):(10-20):(10-20).

[0103] In some embodiments of the present invention, in step S1, the water, thickener, neutralizer, dispersant, and defoamer are added at a rotation speed of 500-800 rpm.

[0104] In some embodiments of the present invention, in step S1, the dispersion time of the water, thickener, neutralizer, dispersant, and defoamer in the dispersion tank is 0.2 to 0.5 hours.

[0105] In some embodiments of the present invention, in step S1, the temperature inside the dispersion tank is (5-10°C) to (40-55°C).

[0106] In some embodiments of the present invention, in step S2, the mass ratio of the inorganic filler to the material obtained in step S1 is (4.0-4.5):(2.0-3.5).

[0107] In some embodiments of the present invention, in step S2, the rotation speed of the dispersion cylinder is 1500-2500 rpm, and the dispersion time is 0.5-1.0 h.

[0108] In some embodiments of the present invention, in step S2, the temperature inside the dispersion tank is 5 to 55°C.

[0109] In some embodiments of the present invention, in step S3, the mass ratio of the aqueous resin, film-forming aid, bactericide and the material obtained in step S2 is (20-25):(1.2-1.8):(0.5-1.0).

[0110] In some embodiments of the present invention, in step S3, the rotation speed of the dispersion cylinder is 500-800 rpm, and the dispersion time is 0.2-0.5 h.

[0111] In some embodiments of the present invention, in step S3, the temperature inside the dispersion tank is 5 to 40°C.

[0112] According to Kirchhoff's laws and the principle of infrared molecular vibration, the functional groups of the film-forming material affect the solar absorption and infrared radiation effects of the coating. Polymer molecules containing π bonds or conjugated π bonds absorb solar radiation more readily; therefore, polymers containing such functional groups should be avoided as much as possible when selecting polymers. In addition, functional groups such as CX, Si-O-Si, and Si-OC bonds can generate higher emissivity within the atmospheric window range. Therefore, this invention selects an acrylic copolymer emulsion as the coating film-forming material.

[0113] Third aspect

[0114] The present invention provides a coating, which is made from the above-described water-based radiative cooling coating, or from the water-based radiative cooling coating obtained by the above-described method.

[0115] In some embodiments of the present invention, the reflectivity of the coating is greater than or equal to 94%.

[0116] In some embodiments of the present invention, the reflectivity of the coating is greater than or equal to 94.15%.

[0117] Fourth aspect

[0118] The present invention provides a method for preparing the above-mentioned coating, wherein the above-mentioned water-based radiative cooling coating or the water-based radiative cooling coating obtained by the above method is applied to the surface of a substrate, and the coating is obtained after drying.

[0119] Example 1

[0120] At 25°C and 600 rpm, 30.0 parts by weight of deionized water, 0.05 parts by weight of cellulose thickener HBR250, 0.50 parts by weight of organic amine neutralizer SN95, 1.00 parts by weight of polycarboxylate dispersant SN5040, and 1.00 parts by weight of mineral oil defoamer 2410AC were added sequentially to a dispersion tank and dispersed for 0.5 h. After dispersion, 30.0 parts by weight of spherical alumina with a particle size of 0.8–1.0 μm, 8.00 parts by weight of spherical calcium carbonate with a particle size of 0.5–0.8 μm, and 2.00 parts by weight of lamellar mesoporous zirconium hydrogen phosphate with a particle size of 0.5–0.8 μm were added sequentially to the dispersion tank, and the speed was adjusted to 2000 rpm. The mixture was dispersed at 30°C for 0.5 h to obtain the first mixture.

[0121] After dispersion, 25.0 parts by weight of acrylate copolymer emulsion 706T, 1.45 parts by weight of film-forming aid 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, and 1.00 parts by weight of bactericide 5-chloro-2-methyl-4-isothiazolin-3-one were added to the first mixture, and dispersion was continued for 0.5 hours. After dispersion was completed, the above-mentioned water-based radiative cooling coating was obtained.

[0122] The water-based radiative cooling coating is uniformly applied to the surface of the substrate and dried at a constant temperature and humidity for 7 days to obtain the radiative cooling coating.

[0123] Example 2

[0124] At 25℃ and 600 rpm, 29.5 parts by weight of deionized water, 0.05 parts by weight of cellulose thickener HBR250, 0.50 parts by weight of organic amine neutralizer SN95, 1.00 parts by weight of polycarboxylate dispersant SN5040, and 1.00 parts by weight of mineral oil defoamer 2410AC were added sequentially to a dispersion tank and dispersed for 0.5 h. After dispersion, 30.0 parts by weight of spherical alumina with a particle size of 0.8–1.0 μm, 8.00 parts by weight of spherical calcium carbonate with a particle size of 0.5–0.8 μm, and 2.50 parts by weight of plate-like mesoporous zirconium hydrogen phosphate with a particle size of 0.5–0.8 μm were added sequentially to the dispersion tank, and the speed was adjusted to 2000 rpm for high-speed dispersion for 0.5 h to obtain the first mixture.

[0125] After dispersion, 25.0 parts by weight of acrylate copolymer emulsion 706T, 1.45 parts by weight of film-forming aid 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, and 1.00 parts by weight of bactericide 5-chloro-2-methyl-4-isothiazolin-3-one were added to the first mixture, and dispersion was continued for 0.5 hours. After dispersion was completed, the above-mentioned water-based radiative cooling coating was obtained.

[0126] The water-based radiative cooling coating is uniformly applied to the surface of the substrate and dried at a constant temperature and humidity for 7 days to obtain the radiative cooling coating.

[0127] Example 3

[0128] At 25℃ and 600 rpm, 29.0 parts by weight of deionized water, 0.05 parts by weight of cellulose thickener HBR250, 0.50 parts by weight of organic amine neutralizer SN95, 1.00 parts by weight of polycarboxylate dispersant SN5040, and 1.00 parts by weight of mineral oil defoamer 2410AC were added sequentially to a dispersion tank and dispersed for 0.5 h. After dispersion, 30.0 parts by weight of spherical alumina with a particle size of 0.8-1.0 μm, 8.00 parts by weight of spherical calcium carbonate with a particle size of 0.5-0.8 μm, and 3.00 parts by weight of plate-like mesoporous zirconium hydrogen phosphate with a particle size of 0.5-0.8 μm were added sequentially to the dispersion tank, and the speed was adjusted to 2000 rpm for high-speed dispersion for 0.5 h to obtain the first mixture.

[0129] After dispersion, 25.0 parts by weight of acrylate copolymer emulsion 706T, 1.45 parts by weight of film-forming aid 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, and 1.00 parts by weight of bactericide 5-chloro-2-methyl-4-isothiazolin-3-one were added to the first mixture, and dispersion was continued for 0.5 hours. After dispersion was completed, the above-mentioned water-based radiative cooling coating was obtained.

[0130] The water-based radiative cooling coating is uniformly applied to the surface of the substrate and dried at a constant temperature and humidity for 7 days to obtain the radiative cooling coating.

[0131] Example 4

[0132] At 25°C and 600 rpm, 28.0 parts by weight of deionized water, 0.05 parts by weight of cellulose thickener HBR250, 0.50 parts by weight of organic amine neutralizer SN95, 1.00 parts by weight of polycarboxylate dispersant SN5040, and 1.00 parts by weight of mineral oil defoamer 2410AC were added sequentially to a dispersion tank and dispersed for 0.5 h. After dispersion, 30.0 parts by weight of spherical alumina with a particle size of 0.8–1.0 μm, 8.00 parts by weight of spherical calcium carbonate with a particle size of 0.5–0.8 μm, and 4.00 parts by weight of plate-like mesoporous zirconium hydrogen phosphate with a particle size of 0.5–0.8 μm were added sequentially to the dispersion tank, and the speed was adjusted to 2000 rpm for high-speed dispersion for 0.5 h to obtain the first mixture.

[0133] After dispersion, 25.0 parts by weight of acrylate copolymer emulsion 706T, 1.45 parts by weight of film-forming aid 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, and 1.00 parts by weight of bactericide 5-chloro-2-methyl-4-isothiazolin-3-one were added to the first mixture, and dispersion was continued for 0.2 to 0.5 hours. After dispersion, the above-mentioned water-based radiative cooling coating was obtained.

[0134] The water-based radiative cooling coating is uniformly applied to the surface of the substrate and dried at a constant temperature and humidity for 7 days to obtain the radiative cooling coating.

[0135] Comparative Example 1

[0136] At 25°C and 600 rpm, 28.0 parts by weight of deionized water, 0.05 parts by weight of cellulose thickener HBR250, 0.50 parts by weight of organic amine neutralizer SN95, 1.00 parts by weight of polycarboxylate dispersant SN5040, and 1.00 parts by weight of mineral oil defoamer 2410AC were added sequentially to a dispersion tank and dispersed for 0.5 h. After dispersion, 32.0 parts by weight of spherical alumina with a particle size of 0.8–1.0 μm and 10.00 parts by weight of spherical calcium carbonate with a particle size of 0.5–0.8 μm were added sequentially to the dispersion tank, and the speed was adjusted to 2000 rpm for high-speed dispersion for 0.5 h to obtain the first mixture.

[0137] After dispersion, 25.0 parts by weight of acrylate copolymer emulsion 706T, 1.45 parts by weight of film-forming aid 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, and 1.00 parts by weight of bactericide 5-chloro-2-methyl-4-isothiazolin-3-one were added to the first mixture, and dispersion was continued for 0.2 to 0.5 hours. After dispersion, the above-mentioned water-based radiative cooling coating was obtained.

[0138] The water-based radiative cooling coating is uniformly applied to the surface of the substrate and dried at a constant temperature and humidity for 7 days to obtain the radiative cooling coating.

[0139] Comparative Example 2

[0140] At 25℃ and 600 rpm, 28.0 parts by weight of deionized water, 0.05 parts by weight of cellulose thickener HBR250, 0.50 parts by weight of organic amine neutralizer SN95, 1.00 parts by weight of polycarboxylate dispersant SN5040, and 1.00 parts by weight of mineral oil defoamer 2410AC were added sequentially to a dispersion tank and dispersed for 0.5 h. After dispersion, 30.0 parts by weight of spherical alumina with a particle size of 0.8–1.0 μm, 8.00 parts by weight of spherical calcium carbonate with a particle size of 0.5–0.8 μm, and 4.00 parts by weight of spherical mesoporous zirconium hydrogen phosphate with a particle size of 8.0–15.0 μm were added sequentially to the dispersion tank, and the speed was adjusted to 2000 rpm for high-speed dispersion for 0.5 h to obtain the first mixture.

[0141] After dispersion, 25.0 parts by weight of acrylate copolymer emulsion 706T, 1.45 parts by weight of film-forming aid 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, and 1.00 parts by weight of bactericide 5-chloro-2-methyl-4-isothiazolin-3-one were added to the first mixture, and dispersion was continued for 0.2 to 0.5 hours. After dispersion, the above-mentioned water-based radiative cooling coating was obtained.

[0142] The water-based radiative cooling coating is uniformly applied to the surface of the substrate and dried at a constant temperature and humidity for 7 days to obtain the radiative cooling coating.

[0143] Comparative Example 3

[0144] At 25°C and 600 rpm, 60.0 parts by weight of deionized water, 0.05 parts by weight of cellulose thickener HBR250, 0.50 parts by weight of organic amine neutralizer SN95, 1.00 parts by weight of polycarboxylate dispersant SN5040, and 1.00 parts by weight of mineral oil defoamer 2410AC were added to a dispersion tank in sequence and dispersed for 0.5 h. After dispersion, 10.00 parts by weight of plate-like mesoporous zirconium hydrogen phosphate with a particle size of 0.5-0.8 μm were added to the dispersion tank, and the speed was adjusted to 2000 rpm for high-speed dispersion for 0.5 h to obtain the first mixture.

[0145] After dispersion, 25.0 parts by weight of acrylate copolymer emulsion 706T, 1.45 parts by weight of film-forming aid 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, and 1.00 parts by weight of bactericide 5-chloro-2-methyl-4-isothiazolin-3-one were added to the first mixture, and dispersion was continued for 0.2 to 0.5 hours. After dispersion, the above-mentioned water-based radiative cooling coating was obtained.

[0146] The water-based radiative cooling coating is uniformly applied to the surface of the substrate and dried at a constant temperature and humidity for 7 days to obtain the radiative cooling coating.

[0147] The performance test results of the coatings obtained in the above embodiments and comparative examples are listed in Table 1 below:

[0148] The solar reflectance was determined according to Appendix A of JG / T235-2014 "Reflective Thermal Insulation Coatings for Buildings". This method uses an ultraviolet-visible-near-infrared spectrophotometer with an integrating sphere to accurately measure the reflectance of the material at different wavelengths. Based on the relative energy distribution of sunlight within the thermal ray wavelength range, the solar reflectance of the material within a certain wavelength range is calculated using a weighted average method. Each sample is tested three times, and the average value is taken as the average solar reflectance. The atmospheric window emissivity was measured using a Fourier transform spectrometer with an integrating sphere, with a test range of 2500–25000 nm and a wavelength interval of 250 nm. After the test, the 800–1300 nm range was selected as the atmospheric window emissivity data. Each sample was tested three times, and the average value was taken as the average atmospheric window emissivity. The contrast ratio test method was performed according to Chapter 6 of GB / T23981.1-2019. Each sample was tested three times, and the average value was taken as the average contrast ratio.

[0149] Table 1. Performance test results of the coatings obtained in each embodiment and comparative example.

[0150]

[0151] The coatings obtained in the above four examples were tested according to the standard for superior-grade topcoats in GB / T9755-2024 "Synthetic Resin Emulsion Wall Coatings". The test results are shown in Table 2.

[0152] Table 2. Application performance test results of the coatings obtained in the embodiments of the present invention.

[0153]

[0154] See Figure 1 The test was conducted from 8:30 AM to 3:00 PM on March 25, 2025, in Hangzhou, Zhejiang Province. During the test period, the average solar radiant power was 949.56 W / m². 2 The average wind speed was 0.77 m / s, and the average ambient humidity was 20.98% RH. The three white paint samples used for temperature testing all had a brightness value of approximately 98.50 and a dry film thickness of approximately 200 μm.

[0155] Test results showed that the average temperature of commercial ordinary white paint was 34.62℃, the average temperature of commercial reflective heat-insulating white paint was 32.94℃, the average temperature of radiative cooling white paint was 28.60℃, and the average ambient temperature was 31.73℃. The average temperature of the radiative cooling white paint was significantly lower than that of the control white paint and the ambient temperature, demonstrating a significant cooling effect.

[0156] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims. Furthermore, specific examples have been used in the specification to illustrate the principles and implementation methods of the present invention. The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention, and the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A water-based radiative cooling coating, characterized in that, The raw materials for the coating include inorganic fillers; The inorganic filler includes mesoporous materials, metal oxides, and carbonates; in, The mesoporous material is lamellar mesoporous zirconium hydrogen phosphate. The metal oxide is at least one of aluminum oxide, zirconium oxide, and magnesium oxide. The carbonate is at least one of calcium carbonate, strontium carbonate, magnesium carbonate, and aluminum carbonate.

2. The water-based radiative cooling coating according to claim 1, characterized in that, The mesoporous material is a plate-like mesoporous zirconium hydrogen phosphate with a particle size of 0.5~0.8μm.

3. The water-based radiative cooling coating according to claim 1, characterized in that, The water-based radiative cooling coating has at least one of the following characteristics: The alumina is spherical alumina; The alumina has a particle size of 0.8~1.0 μm; The calcium carbonate is spherical calcium carbonate; The calcium carbonate has a particle size of 0.5~0.8μm.

4. The water-based radiative cooling coating according to claim 1, characterized in that, It has at least one of the following characteristics: The raw materials of the coating also include a thickener, the content of which is 0.01~0.10 wt.% of the total mass of the coating, and the thickener is at least one of cellulose ether, cellulose ether derivatives, polyurethane, and inorganic thickener; The raw materials of the coating also include a neutralizing agent, the content of which is 0.20~1.00 wt.% of the total mass of the coating, and the neutralizing agent is at least one of organic amine neutralizing agents and inorganic alkali neutralizing agents; The raw materials of the coating also include a dispersant, the content of which is 1.00~3.00 wt.% of the total mass of the coating, and the dispersant is at least one of polycarboxylate type dispersant and polyether type dispersant; The raw materials of the coating also include a defoamer, the content of which is 0.20~1.00 wt.% of the total mass of the coating, and the defoamer is at least one of organosilicon defoamers and mineral oil defoamers; The raw materials of the coating also include water-based resin, the content of which is 25.0~30.0 wt.% of the total mass of the coating, and the water-based resin is at least one of acrylate copolymer emulsion, silicone emulsion, and fluorocarbon emulsion, wherein the viscosity of the acrylate copolymer emulsion is 300~1000 mPa·s; The raw materials of the coating also include film-forming aids, the content of which is 1.00~5.00 wt.% of the total mass of the coating, and the film-forming aids are at least one of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, diisobutyl succinate, and dipropylene glycol butyl ether. The raw materials of the coating also include a bactericide, the content of which is 1.00~3.00 wt.% of the total mass of the coating, and the bactericide is at least one of organosulfur bactericides, organobromine bactericides, quaternary ammonium salt bactericides, and isothiazolinone bactericides; The raw materials of the coating also include water, and the water content is 25.0~45.0 wt.% of the total mass of the coating.

5. A method for preparing an aqueous radiative cooling coating as described in any one of claims 1 to 4, characterized in that, The method includes the following steps: S1, add water, thickener, neutralizer, dispersant and defoamer into the dispersion tank; S2, Inorganic filler is added to the dispersion cylinder; S3, mix the water-based resin, film-forming aid, bactericide and the material obtained in step S2, and disperse them in the dispersion tank to obtain the water-based radiative cooling coating.

6. The method according to claim 5, characterized in that, Step S1 has at least one of the following characteristics: The mass ratio of water, thickener, neutralizer, dispersant, and defoamer is (500~650):(0.5~2.0):(5~10):(10~20):(10~20); Add the water, thickener, neutralizer, dispersant, and defoamer at a rotation speed of 500-800 rpm; The dispersion time of the water, thickener, neutralizer, dispersant, and defoamer in the dispersion tank is 0.2~0.5h; The temperature inside the dispersion tank is (5~10℃)~(40~55℃).

7. The method according to claim 5, characterized in that, Step S2 has at least one of the following characteristics: The mass ratio of the inorganic filler to the material obtained in step S1 is (4.0~4.5):(2.0~3.5); The dispersion cylinder rotates at 1500~2500 rpm, and the dispersion time is 0.5~1.0 h; The temperature inside the dispersion tank is 5~55℃.

8. The method according to claim 5, characterized in that, Step S3 has at least one of the following characteristics: The mass ratio of the aqueous resin, film-forming aid, bactericide, and material obtained in step S2 is (20~25):(1.2~1.8):(0.5~1.0); The dispersion cylinder rotates at 500-800 rpm, and the dispersion time is 0.2-0.5 h. The temperature inside the dispersion tank is 5~40℃.

9. A coating, characterized in that, The coating is made from the water-based radiative cooling coating as described in any one of claims 1 to 4, or from the water-based radiative cooling coating obtained by the method as described in any one of claims 5 to 8; The reflectivity of the coating is greater than or equal to 94%.

10. A method for preparing the coating as described in claim 9, characterized in that, The water-based radiative cooling coating as described in any one of claims 1 to 4, or the water-based radiative cooling coating obtained by the method as described in any one of claims 5 to 8, is applied to the surface of a substrate, and the coating is obtained after drying.

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