A self-layered colored low emissivity coating and its preparation method

Abstract

This invention discloses a self-layering colored low-emissivity coating and its preparation method, belonging to the field of coating materials technology. The self-layering colored low-emissivity coating provided by this invention comprises: a low-emissivity oil-based dispersion mixture and a pigment-water mixture; the low-emissivity oil-based dispersion mixture comprises: flake aluminum powder, solvent A, solvent B, and a first binder; the pigment-water mixture comprises: pigment, solvent C, and a second binder. The self-layering colored low-emissivity coating provided by this invention can spontaneously form a unique double-layer structure after spraying, greatly reducing labor costs and application complexity. Furthermore, the self-layering colored low-emissivity coating provided by this invention has low thermal emissivity (i.e., mid-infrared emissivity) and high near-infrared reflectivity, selectively reflects visible light of the desired color, and exhibits excellent stability.

Description

Technical Field

[0001] This invention relates to the field of coating materials technology, specifically to a self-layering colored low-emissivity coating and its preparation method. Background Technology

[0002] Energy shortages and excessive CO2 emissions are pressing global issues, highlighting the urgent need to reduce energy consumption. In various environments, including construction, transportation, storage, aquaculture, and brewing, a significant portion of energy is used for heating and cooling to maintain appropriate temperatures. Among various thermal regulation strategies, thermal insulation materials play a crucial role in improving energy efficiency by reducing radiative heat transfer. For example, in buildings, thermal insulation materials effectively limit heat loss in winter and prevent heat absorption in summer, thereby significantly reducing heating and cooling energy consumption. This insulation effect not only stabilizes indoor temperatures but also reduces reliance on active heating and cooling systems, ultimately contributing to energy conservation and reduced greenhouse gas emissions under diverse climatic and application conditions.

[0003] Traditional thermal insulation materials are low thermal conductivity materials, which have the ability to inhibit heat conduction. To achieve satisfactory thermal insulation effects, these materials are usually designed with high porosity to absorb air, thereby increasing thermal resistance. Depending on their working mechanism, a thickness of several millimeters to several centimeters is typically required to achieve sufficient thermal insulation. In contrast, thinner, low-emissivity materials achieve insulation by altering their surface radiation properties. Their low emissivity (i.e., high reflectivity) significantly reduces heat radiation exchange, thereby enhancing insulation through radiation control.

[0004] Low-emissivity coatings are generally classified into two types based on their application: transparent and opaque. Transparent low-emissivity coatings are typically used for windows, reflecting infrared heat radiation while allowing visible light to pass through, thus improving energy efficiency without altering the appearance. Opaque coatings, on the other hand, usually have a metallic silver or gray appearance, leading to aesthetic limitations and potential light pollution. In many practical applications, aesthetics are just as important as thermal performance, thus creating a pressing need for colored low-emissivity coatings that combine effective thermal insulation with aesthetic appeal.

[0005] To address this challenge, researchers have explored several methods for creating colored low-emissivity materials, such as surface modification, material mixing, and lamination. However, because the emissivity values ​​are not low enough to meet the requirements for effective thermal insulation performance, the resulting colors often do not meet people's aesthetic expectations.

[0006] Therefore, there is still an urgent need for a self-layering colored low-emissivity coating that is easy to operate, has low emissivity, and provides good thermal insulation. Summary of the Invention

[0007] Peng et al. (Y. Peng et al., "Colorful low-emissivity paints for spaceheating and cooling energy savings," Proceedings of the National Academy of Sciences of the United States of America 120(34), e2300856120 (2023). https: / / doi.org / 10.1073 / pnas.2300856120.) reported a colored self-layering colored low-emissivity paint; however, it requires two separate spraying processes to form a two-layer structure, increasing labor costs and application complexity. This invention, by employing specific solvents A, B, and C, and a specific ratio of isopropanol to water in solvent C, unexpectedly discovered that the resulting coating exhibits self-stratification after spraying. After spraying, the low-emissivity oil dispersion mixture and the pigment-water mixture are immiscible due to their different polarities and automatically stratify due to their different densities, with the pigment-water mixture on top and the low-emissivity oil dispersion mixture on the bottom. After solvent evaporation, a double-layer coating is formed with the pigment layer on top and the aluminum layer on the bottom, significantly reducing labor costs and application complexity, resulting in unexpected technical effects. Furthermore, by employing specific solvents A, B, and C, and a specific ratio of isopropanol to water in solvent C, this invention unexpectedly discovered high near-infrared reflectivity, low mid-infrared emissivity, and excellent high-temperature, low-temperature, and light-induced stability, also exhibiting unexpected technical effects.

[0008] To address the aforementioned technical problems, the present invention provides the following technical solutions.

[0009] In a first aspect, the present invention provides a self-layering colored low emissivity coating.

[0010] A self-layering colored low-emissivity coating comprises: a low-emissivity oil-based dispersion mixture and a pigment-aqueous mixture;

[0011] The low emissivity oil layer dispersion mixture comprises: flake aluminum powder, solvent A, solvent B, and a first binder;

[0012] The pigment-water mixture comprises: pigment, solvent C, and a second binder.

[0013] In some embodiments, solvent A comprises at least one selected from tetrachloroethylene, dichloromethane, perfluorohexane, and 1,1,2,2-tetrachloroethane. In some preferred embodiments, solvent A is tetrachloroethylene.

[0014] In some embodiments, solvent B comprises at least one selected from 1,1,2,2-tetrachloroethane and dichloromethane. In some preferred embodiments, solvent B is 1,1,2,2-tetrachloroethane.

[0015] In some embodiments, the first adhesive comprises polyvinyl butyral. In some embodiments, the first adhesive is polyvinyl butyral.

[0016] In some embodiments, solvent C comprises isopropanol, ethanol, methanol, or a mixture of any alcohol solvent and water. In some preferred embodiments, solvent C is isopropanol and water.

[0017] In some embodiments, solvent C is isopropanol and water, and the volume ratio of isopropanol to water is 3:1 to 1:3. In some embodiments, solvent C is isopropanol and water, and the volume ratio of isopropanol to water is 3:1, 3:2, 1:1, 2:3, or 1:3. In some embodiments, solvent C is isopropanol and water, and the volume ratio of isopropanol to water is 3:2 to 1:3.

[0018] In some embodiments, the second adhesive comprises at least one of polyvinyl alcohol, nitrile rubber, or epoxy resin. In some preferred embodiments, the second adhesive is polyvinyl alcohol.

[0019] In some embodiments, the pigment comprises an inorganic pigment. In some embodiments, the pigment comprises at least one of Prussian blue, iron oxide, and goethite.

[0020] In some embodiments, the sheet diameter of the aluminum powder is 10 μm-120 μm. In some embodiments, the sheet diameter of the aluminum powder is 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm or 120 μm.

[0021] In some embodiments, each 1 g of the flake aluminum powder corresponds to 2.5 ml to 10 ml of solvent A. In some embodiments, each 1 g of the flake aluminum powder corresponds to 2.5 ml, 2.75 ml, 3 ml, 3.5 ml, 4 ml, 4.5 ml, 5 ml, 5.5 ml, 6 ml, 7 ml, 8 ml, 9 ml, or 10 ml of solvent A. In some embodiments, each 1 g of the flake aluminum powder corresponds to 2.75 ml to 10 ml of solvent A.

[0022] In some embodiments, each 1 g of the first adhesive corresponds to 50 ml to 150 ml of solvent B. In some embodiments, each 1 g of the first adhesive corresponds to 50 ml, 60 ml, 70 ml, 71 ml, 72 ml, 73 ml, 74 ml, 75 ml, 80 ml, 85 ml, 90 ml, 100 ml, 110 ml, 120 ml, 130 ml, 140 ml, or 150 ml of solvent B. In some embodiments, each 1 g of the first adhesive corresponds to 73 ml to 100 ml of solvent B.

[0023] In some embodiments, the mass ratio of the first adhesive to the flake aluminum powder is 1:20-1:500. In some embodiments, the mass ratio of the first adhesive to the flake aluminum powder is 1:20, 1:30, 1:40, 1:50, 1:60, 1:70, 1:72, 1:73, 1.5:110, 1:74, 1:80, 1:81, 1:82, 1:83, 1:84, 1:85, 1:90, 1:100, 1:110, 1:120, 1:130, 1:140, 1:150, 1:200, 1:250, 1:300, 1:350, 1:400, 1:450, or 1:500. In some embodiments, the mass ratio of the first adhesive to the flake aluminum powder is 1:20-1:500. In some embodiments, the mass ratio of the first adhesive to the flake aluminum powder is 1.5:110 to 1:100. In some embodiments, the mass ratio of the first adhesive to the flake aluminum powder is 1.5:110, 1:80, or 1:100.

[0024] In some embodiments, the mass ratio of the pigment to the flake aluminum powder is 1:110-50:110. In some embodiments, the mass ratio of the pigment to the flake aluminum powder is 1:110-5:110. In some embodiments, the mass ratio of the pigment to the flake aluminum powder is 1:110, 2:110, 3:110, 3.3:110, 3.85:110, 4:110, or 5:110. In some embodiments, the mass ratio of the pigment to the flake aluminum powder is 3.3:110-5:110.

[0025] In some embodiments, the volume ratio of solvent C to the mass of the pigment is 0.6 ml:1 mg to 0.6 ml:50 mg. In some embodiments, the volume ratio of solvent C to the mass of the pigment is 0.6 ml:1 mg, 0.6 ml:2 mg, 0.6 ml:3 mg, 0.6 ml:4 mg, 0.6 ml:5 mg, 0.6 ml:6 mg, 0.6 ml:7 mg, 0.6 ml:8 mg, 0.6 ml:9 mg, 0.6 ml:10 mg, 0.6 ml:15 mg, 0.6 ml:20 mg, 0.6 ml:25 mg, 0.6 ml:30 mg, 0.6 ml:35 mg, 0.6 ml:40 mg, 0.6 ml:45 mg, or 0.6 ml:50 mg. In some embodiments, the volume ratio of solvent C to the mass of the pigment is 0.6 ml:4 mg to 0.6 ml:7 mg.

[0026] In some embodiments, the volume ratio of solvent C to the mass ratio of the second adhesive is 0.6 ml:10 mg to 0.6 ml:40 mg.

[0027] In some embodiments, solvent A is tetrachloroethylene; solvent B is 1,1,2,2-tetrachloroethane; the first binder is polyvinyl butyral; the pigment includes at least one selected from Prussian blue, iron oxide, and goethite; solvent C is isopropanol and water; the second binder is polyvinyl alcohol; the volume ratio of isopropanol to water is 3:2-1:3; each g of the flake aluminum powder corresponds to 2.75 ml-10 ml of solvent A; each g of the first binder corresponds to 73 ml-100 ml of solvent B; the mass ratio of the first binder to the flake aluminum powder is 1.5:110-1:100; the mass ratio of the pigment to the flake aluminum powder is 3.3:110-5:110; the volume ratio of solvent C to the mass of the pigment is 0.6 ml:4 mg-0.6 ml:7 mg; the volume ratio of solvent C to the mass of the second binder is 0.6 ml:10 mg-0.6 ml:40 mg.

[0028] In some embodiments, solvent A is tetrachloroethylene; solvent B is 1,1,2,2-tetrachloroethane; the first binder is polyvinyl butyral; the pigment includes at least one selected from Prussian blue, iron oxide, and goethite; solvent C is isopropanol and water; the second binder is polyvinyl alcohol; the volume ratio of isopropanol to water is 1:1; each 1 g of the flake aluminum powder is mixed with 5 ml of solvent A; each 1 g of the first binder is mixed with 100 ml of solvent B; the mass ratio of the first binder to the flake aluminum powder is 1:100; the mass ratio of the pigment to the flake aluminum powder is 5:110; the volume ratio of solvent C to the mass of the pigment is 0.6 ml:5 mg; the volume ratio of solvent C to the mass of the second binder is 0.6 ml:20 mg.

[0029] In some embodiments, solvent A is tetrachloroethylene; solvent B is 1,1,2,2-tetrachloroethane; the first binder is polyvinyl butyral; the pigment includes at least one selected from Prussian blue, iron oxide, and goethite; solvent C is isopropanol and water; the second binder is polyvinyl alcohol; the volume ratio of isopropanol to water is 2:3; each 1 g of the flake aluminum powder is mixed with 10 ml of solvent A; each 1 g of the first binder is mixed with 73 ml of solvent B; the mass ratio of the first binder to the flake aluminum powder is 1.5:110; the mass ratio of the pigment to the flake aluminum powder is 4:110; the volume ratio of solvent C to the mass of the pigment is 0.6 ml:4 mg; the volume ratio of solvent C to the mass of the second binder is 0.6 ml:10 mg.

[0030] In some embodiments, solvent A is tetrachloroethylene; solvent B is 1,1,2,2-tetrachloroethane; the first binder is polyvinyl butyral; the pigment includes at least one selected from Prussian blue, iron oxide, and goethite; solvent C is isopropanol and water; the second binder is polyvinyl alcohol; the volume ratio of isopropanol to water is 3:2; each 1 g of the flake aluminum powder corresponds to 2.75 ml-10 ml of solvent A; each 1 g of the first binder corresponds to 75 ml of solvent B; the mass ratio of the first binder to the flake aluminum powder is 1:100; the mass ratio of the pigment to the flake aluminum powder is 3.3:110; the volume ratio of solvent C to the mass of the pigment is 0.6 ml:6 mg; the volume ratio of solvent C to the mass of the second binder is 0.6 ml:30 mg.

[0031] In some embodiments, solvent A is tetrachloroethylene; solvent B is 1,1,2,2-tetrachloroethane; the first binder is polyvinyl butyral; the pigment includes at least one selected from Prussian blue, iron oxide, and goethite; solvent C is isopropanol and water; the second binder is polyvinyl alcohol; the volume ratio of isopropanol to water is 1:3; each 1 g of the flake aluminum powder corresponds to 5.5 ml of solvent A; each 1 g of the first binder corresponds to 80 ml of solvent B; the mass ratio of the first binder to the flake aluminum powder is 1:80; the mass ratio of the pigment to the flake aluminum powder is 3.85:110; the volume ratio of solvent C to the mass of the pigment is 0.6 ml:7 mg; the volume ratio of solvent C to the mass of the second binder is 0.6 ml:40 mg.

[0032] In a second aspect, the present invention provides a method for preparing the self-layered colored low emissivity coating described in the first aspect.

[0033] A method for preparing a self-layered colored low-emissivity coating as described in the first aspect, comprising:

[0034] (1) Dissolve the first adhesive in solvent B to obtain a first adhesive solution; dissolve the second adhesive in a portion of the formulation amount of solvent C to obtain a second adhesive solution;

[0035] (2) Mix the flake aluminum powder, the first binder solution and solvent A to obtain the low emissivity oil layer dispersion mixture;

[0036] (3) Mix the pigment, the second binder solution and the remaining amount of solvent C to obtain the pigment aqueous mixture;

[0037] (4) Mix the low emissivity oil layer dispersion mixture and the pigment water layer mixture to obtain the self-layered colored low emissivity coating.

[0038] In some embodiments, the amount of solvent C added in step (1) is five-twelfths to ten-twelfths of the formulation amount of solvent C. In some embodiments, the amount of solvent C added in step (1) is five-twelfths, six-twelfths, seven-twelfths, eight-twelfths, nine-twelfths, four-fifths, or ten-twelfths of the formulation amount of solvent C.

[0039] Thirdly, the present invention provides a low emissivity product or thermal insulation material.

[0040] In some embodiments, a low-emissivity article has its surface coated with the self-layered colored low-emissivity coating described in the first aspect or the self-layered colored low-emissivity coating prepared by the preparation method described in the second aspect.

[0041] In some embodiments, a thermal insulation material has its surface coated with the self-layered colored low emissivity coating described in the first aspect or the self-layered colored low emissivity coating prepared by the preparation method described in the second aspect. Beneficial effects

[0042] Compared with the prior art, a certain technical solution of the present invention has at least one of the following beneficial technical effects:

[0043] (1) The self-layering colored low-emissivity coating provided by this invention can spontaneously layer after spraying, wherein the pigment-water mixture is on the upper layer and the low-emissivity oil dispersion mixture is on the lower layer. After the solvent evaporates, a double-layer coating is formed with a pigment layer on the upper layer and an aluminum layer on the lower layer, which greatly reduces labor costs and application complexity, and has unexpected technical effects. In addition, the self-layering colored low-emissivity coating provided by this invention can spontaneously layer to form a pigment layer and an aluminum layer after spraying, with the pigment layer covering the aluminum layer. Depending on the different pigments, different colors are formed, which has excellent aesthetic effects and avoids the light pollution caused by a single metallic silver or gray appearance.

[0044] (2) The self-layering colored low-emissivity coating provided by this invention has high near-infrared reflectivity. Under intense sunlight in summer, high near-infrared reflectivity allows a large amount of near-infrared light to be reflected, which helps reduce the absorption of solar heat by the coated object. At the same time, the self-layering colored low-emissivity coating provided by this invention has low thermal emissivity (i.e., mid-infrared emissivity), which prevents heat from the surrounding environment from entering the interior of the object coated with the self-layering colored low-emissivity coating provided by this invention, thereby reducing cooling energy consumption. In winter, low thermal emissivity (i.e., mid-infrared emissivity) helps retain the heat inside the object coated with the self-layering colored low-emissivity coating provided by this invention, preventing heat from being lost to the outside environment too quickly, which helps maintain indoor heat, reduce heat loss, and save heating energy consumption.

[0045] (3) Compared with other solvents A (such as cyclohexane, acetone or xylene), the solvent A provided by the present invention (such as tetrachloroethylene) is beneficial to the formation of self-separation in the obtained coating, which has unexpected technical effects.

[0046] (4) Compared with other solvents A (such as cyclohexane, acetone or xylene), the solvent A provided by the present invention (such as tetrachloroethylene) is beneficial to reduce the mid-infrared (wavelength 4 μm - 16 μm) emissivity of the obtained coating and increase the near-infrared (wavelength 780 nm - 2000 nm) reflectivity of the obtained coating, which has unexpected technical effects.

[0047] (5) Compared with other solvents B (such as isopropanol, ethanol or acetone), the solvent B provided by the present invention (such as 1,1,2,2-tetrachloroethane) is beneficial to the formation of self-separation in the resulting coating, which has unexpected technical effects.

[0048] (6) Compared with other solvents B (such as isopropanol, ethanol or acetone), the solvent B provided by the present invention (such as 1,1,2,2-tetrachloroethane) is beneficial to reduce the mid-infrared (wavelength 4 μm - 16 μm) emissivity of the obtained coating and increase the near-infrared (wavelength 780 nm - 2000 nm) reflectivity of the obtained coating, which has unexpected technical effects.

[0049] (7) Compared with other solvents C (such as isopropanol or acetone), the solvent C provided by the present invention (such as a mixture of isopropanol and water) is beneficial to the formation of self-separation in the resulting coating, which has unexpected technical effects.

[0050] (8) Compared with other solvents C (such as water, isopropanol or acetone), the solvent C provided by the present invention (such as a mixture of isopropanol and water) is beneficial to reduce the mid-infrared (wavelength 4μm - 16μm) emissivity of the obtained coating and increase the near-infrared (wavelength 780 nm - 2000 nm) reflectivity of the obtained coating, which has unexpected technical effects.

[0051] (9) Compared with other volume ratios of isopropanol and water in solvent C (such as isopropanol:water (V:V) = 20:1-10:1), the volume ratio of isopropanol and water in solvent C provided by the present invention (such as isopropanol:water (V:V) = 3:2-1:3) is beneficial to the formation of self-separation in the resulting coating, and has unexpected technical effects.

[0052] (10) Compared with other volume ratios of isopropanol and water in solvent C (such as isopropanol:water (V:V) = 20:1-1:10), the volume ratio of isopropanol and water in solvent C provided by the present invention (such as isopropanol:water (V:V) = 3:2-1:3) is beneficial to reduce the mid-infrared (wavelength 4 μm - 16 μm) emissivity of the obtained coating and increase the near-infrared (wavelength 780 nm - 2000 nm) reflectivity of the obtained coating, which has unexpected technical effects.

[0053] (11) Compared with other solvents A, the coatings obtained by using solvent A (such as tetrachloroethylene) provided by the present invention have better high-temperature, low-temperature and light-illumination stability of mid-infrared (wavelength 4 μm - 16 μm) emissivity and high-temperature, low-temperature and light-illumination stability of near-infrared (wavelength 780 nm - 2000 nm) reflectivity, and have unexpected technical effects.

[0054] (12) Compared with other solvents B, the coatings obtained by using solvent B (such as 1,1,2,2-tetrachloroethane) provided by the present invention have better high-temperature, low-temperature and light-illumination stability of mid-infrared (wavelength 4 μm - 16 μm) emissivity and high-temperature, low-temperature and light-illumination stability of near-infrared (wavelength 780 nm - 2000 nm) reflectivity, and have unexpected technical effects.

[0055] (13) Compared with other solvents C, the coatings obtained by using the solvent C provided by the present invention (such as a mixture of isopropanol and water) have better high-temperature, low-temperature and light-illumination stability of mid-infrared (wavelength 4 μm - 16 μm) emissivity and high-temperature, low-temperature and light-illumination stability of near-infrared (wavelength 780 nm - 2000 nm) reflectivity, and have unexpected technical effects.

[0056] (14) Compared with other volume ratios of isopropanol and water in solvent C, the coatings obtained by using the volume ratio of isopropanol and water in solvent C provided by the present invention (such as isopropanol:water (V:V) = 3:2-1:3) have better high-temperature, low-temperature and light-illumination stability of mid-infrared (wavelength 4 μm - 16 μm) emissivity and high-temperature, low-temperature and light-illumination stability of near-infrared (wavelength 780 nm - 2000 nm) reflectivity, and have unexpected technical effects.

[0057] (15) The self-layered colored low emissivity coating provided by the present invention is beneficial to the insulation of heat transfer and has excellent thermal insulation performance.

[0058] Terminology Explanation

[0059] Before describing the invention in more detail, it should be understood that the invention is not limited to the specific embodiments described herein, as such embodiments can vary. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. All publications and patents referenced herein are incorporated herein by reference in their entirety.

[0060] Where numerical ranges are provided, it should be understood that, unless the context clearly indicates otherwise, interpolated values ​​between the upper and lower limits of the range, and any other stated or interpolated values ​​within the range, are covered within the invention, up to one-tenth of the lower limit unit. The upper and lower limits of these smaller ranges may be independently included within the smaller range and are also covered within the invention, subject to any specific exclusion restrictions within the range. Where the range includes one or both of the limits, ranges excluding any one or both of the limits are also included in the invention.

[0061] The term "wt%" indicates a weight percentage.

[0062] In the following content, all figures disclosed herein, whether or not they use the words "approximately" or "about," are approximate values. The value of each figure may vary by 1%, 2%, 5%, 7%, 8%, 10%, 15%, or 20%. Whenever a figure with a value of N is disclosed, any figure with a value of N+ / -1%, N+ / -2%, N+ / -3%, N+ / -5%, N+ / -7%, N+ / -8%, N+ / -10%, N+ / -15%, or N+ / -20% will be explicitly disclosed, where "+ / -" indicates addition or subtraction.

[0063] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0064] The terms “comprising” or “including” are open-ended expressions, meaning they include the contents specified in this invention but do not exclude other aspects.

[0065] In this invention, the term "flake diameter" refers to the diameter corresponding to the circumcircle of the particle. This circumcircle can just contain the aluminum powder particle, and its diameter is used as a numerical value to measure the flake diameter.

[0066] The term "V:V" indicates a volume ratio.

[0067] In this invention, the volume-to-mass ratio specifically refers to the ratio between the volume of a corresponding component and its mass within the coating. This ratio is not intended to limit the actual amount of the corresponding component added to the coating. For example, when stated as "the volume ratio of solvent C to the mass of the second binder is 0.6 ml:10 mg," it means that for every 0.6 ml of solvent C added, 10 mg of the second binder needs to be added. However, this does not mean that the actual volume of solvent C in the coating is fixed at 0.6 ml, or that the actual mass of the second binder is fixed at 10 mg.

[0068] Prussian blue is a coordination compound, also known as Tönnies blue or ferric ferrocyanide, with the English name Prussian Blue and the abbreviation PB. Its molecular formula is Fe4(Fe(CN)6)3.

[0069] The term "iron oxide" refers to ferric oxide.

[0070] The term "goethite" refers to α-FeOOH (i.e., α-type hydroxy iron oxide). Detailed Implementation

[0071] The present invention will be explained below with reference to embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0072] I. Paint Spraying Method:

[0073] Unless otherwise stated, the self-layering colored low-emissivity coatings of the following embodiments or the coatings of the comparative examples are sprayed according to the following operation:

[0074] Using 40 mm × 50 mm × 1 mm glass as a substrate, the material was rinsed sequentially with deionized water, ethanol, and acetone, and finally dried with nitrogen. The coating material was shaken well and then sprayed onto the substrate using a spraying method. The spray gun pressure was set to 200 kPa, and a 0.5 mm nozzle (SIBONGD, S-CP2-0.5) was used. During spraying, the tip of the spray gun was approximately 0.1 meters from the substrate. After the coating dried naturally, a coating with a total thickness of approximately 15 μm was obtained, consisting of a pigment layer and an aluminum layer.

[0075] II. Methods for detecting mid-infrared reflectance:

[0076] The tests were conducted using a Fourier transform infrared spectrometer with an integrating sphere.

[0077] Instrument manufacturer and model: Thermo Fisher Scientific, USA, Nicolet iS50.

[0078] Point ball: PIKE.

[0079] III. Methods for detecting near-infrared reflectance:

[0080] The tests were conducted using an ultraviolet / visible / near-infrared spectrophotometer with an integrating sphere.

[0081] Instrument manufacturer and model: PerkinElmer, Lambda1050+.

[0082] Examples 1-4: Self-layering colored low-emissivity coatings

[0083] Formula: See Table 1.

[0084] Table 1: Formulations of Self-Laminating Colored Low Emissivity Coatings

[0085]

[0086] Preparation method:

[0087] (1) Dissolve the first adhesive in solvent B to obtain the first adhesive solution; dissolve the second adhesive in five-sixths of the formula amount of solvent C to obtain the second adhesive solution;

[0088] (2) Mix the flake aluminum powder, the first binder solution and solvent A to obtain the low emissivity oil layer dispersion mixture;

[0089] (3) Mix the pigment, the second binder solution and the remaining amount of solvent C to obtain the pigment aqueous mixture;

[0090] (4) Mix the low emissivity oil layer dispersion mixture and the pigment water layer mixture, oscillate and sonicate to obtain the self-layered colored low emissivity coating.

[0091] Examples 5-6: Self-layering colored low-emissivity coatings with different pigments

[0092] Based on the formulation and preparation method of Example 1, Prussian blue was replaced with an equal mass of iron oxide to obtain the self-layering colored low emissivity coating of Example 5.

[0093] Based on the formulation and preparation method of Example 1, Prussian blue was replaced with an equal mass of goethite to obtain the self-layered colored low emissivity coating of Example 6.

[0094] Comparative Examples 1-3: Investigation of Solvent A

[0095] The coatings of Comparative Examples 1-3 differ from those of Example 1 in that the type of solvent A is different. Otherwise, they are the same as those of Example 1. The specific selection of solvent A for Comparative Examples 1-3 is shown in Table 2. The coatings of Comparative Examples 1-3 were obtained.

[0096] Table 2: Investigation of Solvent A

[0097] Comparative Example Solvent A Comparative Example 1 Cyclohexane Comparative Example 2 acetone Comparative Example 3 xylene

[0098] Comparative Examples 4-6: Investigation of Solvent B

[0099] The coatings of Comparative Examples 4-6 differ from those of Example 1 in that the type of solvent B is different. Otherwise, they are the same as those of Example 1. The specific selection of solvent B in Comparative Examples 4-6 is shown in Table 3, thus obtaining the coatings of Comparative Examples 4-6.

[0100] Table 3: Investigation of Solvent B

[0101] Comparative Example Solvent B Comparative Example 4 Isopropanol Comparative Example 5 ethanol Comparative Example 6 acetone

[0102] Comparative Examples 7-9: Investigation of Solvent C

[0103] The coatings of Comparative Examples 7-9 differ from those of Example 1 in that the type of solvent C is different. Otherwise, they are the same as those of Example 1. The specific selection of solvent C for Comparative Examples 7-9 is shown in Table 4, thus obtaining the coatings of Comparative Examples 7-9.

[0104] Table 4: Investigation of solvent C

[0105] Comparative Example Solvent C Comparative Example 7 water Comparative Example 8 Isopropanol Comparative Example 9 acetone

[0106] Comparative Examples 10-12: Investigation of the ratio of isopropanol to water in solvent C

[0107] The coatings of Comparative Examples 10-12 differ from those of Example 1 in that the ratio of isopropanol to water in solvent C is different. Otherwise, they are the same as those of Example 1. The specific selection of the ratio of isopropanol to water in solvent C for Comparative Examples 7-9 is shown in Table 5, thus obtaining the coatings of Comparative Examples 10-12.

[0108] Table 5: Investigation of the ratio of isopropanol to water in solvent C

[0109] Comparative Example Volume ratio of isopropanol to water (isopropanol:water (V:V)) Comparative Example 10 10:1 Comparative Example 11 20:1 Comparative Example 12 1:10

[0110] Experimental Example 1: Emissivity and Reflectivity Detection

[0111] The self-layered colored low emissivity coatings obtained in the above embodiments and the coatings obtained in the comparative examples were sprayed (sprayed according to the operation under "I. Coating Spraying Method" above). After drying to form a coating, the mid-infrared (wavelength 4 μm - 16 μm) emissivity, near-infrared (wavelength 780 nm - 2000 nm) reflectivity and self-layering effect were tested. The test results are shown in Table 6.

[0112] Table 6: Results of Emissivity and Reflectivity Measurements

[0113] coating Mid-infrared (wavelength 4 μm - 16 μm) emissivity Near-infrared (wavelength 780 nm - 2000 nm) reflectance Whether it is self-layered (whether the pigment layer is on top and the aluminum layer is on the bottom). Example 1 0.107 0.892 yes Example 2 0.121 0.773 yes Example 3 0.105 0.786 yes Example 4 0.138 0.771 yes Example 5 0.160 0.840 yes Example 6 0.139 0.863 yes Comparative Example 1 0.285 0.765 no Comparative Example 2 0.396 0.705 no Comparative Example 3 0.151 0.891 no Comparative Example 4 0.370 0.712 no Comparative Example 5 0.349 0.709 no Comparative Example 6 0.325 0.695 no Comparative Example 7 0.285 0.689 yes Comparative Example 8 0.378 0.714 no Comparative Example 9 0.347 0.769 no Comparative Example 10 0.327 0.701 no Comparative Example 11 0.374 0.652 no Comparative Example 12 0.276 0.716 yes

[0114] Results analysis:

[0115] (1) Compared with other solvents A (such as cyclohexane (Comparative Example 1), acetone (Comparative Example 2) or xylene (Comparative Example 3), the solvent A provided by the present invention (such as tetrachloroethylene in Examples 1-6) is beneficial to the formation of self-separation in the obtained coating, which has unexpected technical effects.

[0116] (2) Compared with other solvents A (such as cyclohexane (Comparative Example 1), acetone (Comparative Example 2) or xylene (Comparative Example 3), the use of solvent A provided by the present invention (such as tetrachloroethylene in Examples 1-6) is beneficial to reduce the mid-infrared (wavelength 4 μm - 16 μm) emissivity of the obtained coating and increase the near-infrared (wavelength 780 nm - 2000 nm) reflectivity of the obtained coating, which has unexpected technical effects.

[0117] (3) Compared with other solvents B (such as isopropanol (Comparative Example 4), ethanol (Comparative Example 5) or acetone (Comparative Example 6), the solvent B provided by the present invention (such as 1,1,2,2-tetrachloroethane in Examples 1-6) is beneficial to the formation of self-separation in the obtained coating, which has unexpected technical effects.

[0118] (4) Compared with other solvents B (such as isopropanol (Comparative Example 4), ethanol (Comparative Example 5) or acetone (Comparative Example 6), the solvent B provided by the present invention (such as 1,1,2,2-tetrachloroethane in Examples 1-6) is beneficial to reduce the mid-infrared (wavelength 4 μm - 16 μm) emissivity of the obtained coating and increase the near-infrared (wavelength 780 nm - 2000 nm) reflectivity of the obtained coating, which has unexpected technical effects.

[0119] (5) Compared with other solvents C (such as isopropanol (Comparative Example 8) or acetone (Comparative Example 9), the solvent C provided by the present invention (such as isopropanol and water in Examples 1-4) is beneficial to the formation of self-separation of the obtained coating, which has unexpected technical effects.

[0120] (6) Compared with other solvents C (such as water (Comparative Example 7), isopropanol (Comparative Example 8) or acetone (Comparative Example 9), the solvent C provided by the present invention (such as isopropanol and water in Examples 1-6) is beneficial to reduce the mid-infrared (wavelength 4 μm - 16 μm) emissivity of the obtained coating and increase the near-infrared (wavelength 780 nm - 2000 nm) reflectivity of the obtained coating, which has unexpected technical effects.

[0121] (7) Compared with other volume ratios of isopropanol and water in solvent C (such as isopropanol:water (V:V) = 20:1-10:1 (Comparative Example 10-Comparative Example 11)), the volume ratio of isopropanol and water in solvent C provided by the present invention (such as isopropanol:water (V:V) = 3:2-1:3 in Examples 1-6) is beneficial to the formation of self-separation in the obtained coating, and has unexpected technical effects.

[0122] (8) Compared with other volume ratios of isopropanol and water in solvent C (such as isopropanol:water (V:V) = 20:1-1:10 (Comparative Examples 10-13)), the volume ratio of isopropanol and water in solvent C provided by the present invention (such as isopropanol:water (V:V) = 3:2-1:3 in Examples 1-6) is beneficial to reduce the mid-infrared (wavelength 4 μm - 16 μm) emissivity of the obtained coating and increase the near-infrared (wavelength 780 nm - 2000 nm) reflectivity of the obtained coating, which has unexpected technical effects.

[0123] Experimental Example 2: Stability Study

[0124] 1. High temperature stability

[0125] The layered colored low emissivity coatings obtained in the above examples and the coatings obtained in each comparative example were sprayed according to the operation under "I. Coating Spraying Method" above. After drying to form a coating, the mid-infrared (wavelength 4 μm - 16 μm) emissivity and near-infrared (wavelength 780 nm - 2000 nm) reflectivity were measured. Then, the coatings were placed under high temperature (80 ℃) conditions for 6 months, and the mid-infrared (wavelength 4 μm - 16 μm) emissivity and near-infrared (wavelength 780 nm - 2000 nm) reflectivity were measured. The results are shown in Table 7.

[0126] Table 7: Stability study at high temperature (80 °C) for 6 months

[0127] coating Mid-infrared (wavelength 4 μm - 16 μm) emissivity Near-infrared (wavelength 780 nm - 2000 nm) reflectance Example 1 - Before placing under high temperature conditions 0.106 0.893 Example 2 - Before placing under high temperature conditions 0.122 0.772 Example 3 - Before placing under high temperature conditions 0.104 0.785 Example 4 - Before placing under high temperature conditions 0.137 0.772 Example 5 - Before placing under high temperature conditions 0.160 0.841 Example 6 - Before placing under high temperature conditions 0.139 0.864 Comparative Example 2 - Before being placed under high temperature conditions 0.396 0.704 Comparative Example 8 - Before being placed under high temperature conditions 0.377 0.715 Comparative Example 12 - Before being placed under high temperature conditions 0.277 0.715 Example 1: High temperature for 6 months 0.109 0.892 Example 2: High temperature for 6 months 0.123 0.772 Example 3: High temperature for 6 months 0.109 0.781 Example 4: High temperature for 6 months 0.141 0.765 Example 5: High temperature for 6 months 0.162 0.838 Example 6: High temperature for 6 months 0.140 0.860 Comparative Example 2: High Temperature for 6 Months 0.457 0.587 Comparative Example 8: High Temperature for 6 Months 0.478 0.592 Comparative Example 12: High Temperature for 6 Months 0.509 0.621

[0128] 2. Low temperature stability

[0129] The layered colored low emissivity coatings obtained in the above examples and the coatings obtained in each comparative example were sprayed according to the operation under "I. Coating Spraying Method" above. After drying to form a coating, the mid-infrared (wavelength 4μm - 16 μm) emissivity and near-infrared (wavelength 780 nm - 2000 nm) reflectivity were measured. Then, the coatings were placed under low temperature (-20 ℃) ​​conditions for 6 months, and the mid-infrared (wavelength 4 μm - 16 μm) emissivity and near-infrared (wavelength 780 nm - 2000 nm) reflectivity were measured. The results are shown in Table 8.

[0130] Table 8: Stability study at low temperature (-20 ℃) ​​for 6 months

[0131] coating Mid-infrared (wavelength 4 μm - 16 μm) emissivity Near-infrared (wavelength 780 nm - 2000 nm) reflectance Example 1 - Before placing under low temperature conditions 0.107 0.893 Example 2 - Before placing under low temperature conditions 0.121 0.772 Example 3 - Before placing under low temperature conditions 0.104 0.786 Example 4 - Before placing under low temperature conditions 0.138 0.772 Example 5 - Before placing under low temperature conditions 0.161 0.840 Example 6 - Before placing under low temperature conditions 0.138 0.865 Comparative Example 2 - Before being placed under low temperature conditions 0.395 0.705 Comparative Example 8 - Before being placed under low temperature conditions 0.378 0.713 Comparative Example 12 - Before being placed under low temperature conditions 0.275 0.717 Example 1: Low temperature for 6 months 0.107 0.892 Example 2: Low temperature for 6 months 0.122 0.773 Example 3: Low temperature for 6 months 0.108 0.786 Example 4: Low temperature for 6 months 0.139 0.770 Example 5: Low temperature for 6 months 0.161 0.839 Example 6: Low temperature for 6 months 0.140 0.858 Comparative Example 2: Low Temperature for 6 Months 0.431 0.684 Comparative Example 8: Low Temperature for 6 Months 0.458 0.612 Comparative Example 12: Low Temperature for 6 Months 0.341 0.598

[0132] 3. Light stability

[0133] The layered colored low-emissivity coatings obtained in the above embodiments and the coatings obtained in the comparative examples were sprayed according to the operation under "I. Coating Spraying Method" above. After drying to form a coating, the mid-infrared (wavelength 4 μm - 16 μm) emissivity and near-infrared (wavelength 780 nm - 2000 nm) reflectivity were measured. Then, an ultraviolet lamp (350 mW / cm²) was placed in a transparent container. 2 After being placed under irradiation conditions for 6 months, the mid-infrared (wavelength 4 μm - 16 μm) emissivity and near-infrared (wavelength 780 nm - 2000 nm) reflectivity were measured. The results are shown in Table 9.

[0134] Table 9: Ultraviolet lamp (350 mW / cm²) 2 According to the 6-month stability study

[0135] coating Mid-infrared (wavelength 4 μm - 16 μm) emissivity Near-infrared (wavelength 780 nm - 2000 nm) reflectance Example 1 - Before placing under ultraviolet lamp irradiation conditions 0.108 0.891 Example 2 - Before placing under ultraviolet light irradiation conditions 0.120 0.771 Example 3 - Before placing under ultraviolet light irradiation conditions 0.103 0.787 Example 4 - Before placing under ultraviolet light irradiation conditions 0.139 0.771 Example 5 - Before placing under UV lamp irradiation conditions 0.161 0.841 Example 6 - Before placing under UV lamp irradiation conditions 0.139 0.865 Comparative Example 2 - Before UV lamp irradiation 0.396 0.704 Comparative Example 8 - Before UV lamp irradiation 0.378 0.715 Comparative Example 12 - Before UV Lamp Irradiation 0.275 0.716 Example 1: UV lamp irradiation for 6 months 0.110 0.890 Example 2: UV lamp irradiation for 6 months 0.126 0.771 Example 3: UV lamp irradiation for 6 months 0.111 0.779 Example 4: UV lamp irradiation for 6 months 0.139 0.769 Example 5: UV lamp irradiation for 6 months 0.163 0.836 Example 6: UV lamp irradiation for 6 months 0.143 0.857 Comparative Example 2: UV lamp irradiation for 6 months 0.554 0.603 Comparative Example 8: UV lamp irradiation for 6 months 0.567 0.612 Comparative Example 12: UV lamp irradiation for 6 months 0.454 0.517

[0136] in conclusion:

[0137] (1) Compared with other solvents A, the coatings obtained by using solvent A provided by the present invention (such as tetrachloroethylene in Examples 1-6) have better high-temperature, low-temperature and light-illumination stability of mid-infrared (wavelength 4 μm - 16 μm) emissivity and high-temperature, low-temperature and light-illumination stability of near-infrared (wavelength 780 nm - 2000 nm) reflectivity, and have unexpected technical effects.

[0138] (2) Compared with other solvents B, the coatings obtained by using solvent B provided by the present invention (such as 1,1,2,2-tetrachloroethane in Examples 1-6) have better high-temperature, low-temperature and light-illumination stability of mid-infrared (wavelength 4 μm - 16 μm) emissivity and high-temperature, low-temperature and light-illumination stability of near-infrared (wavelength 780 nm - 2000 nm) reflectivity, and have unexpected technical effects.

[0139] (3) Compared with other solvents C, the coatings obtained by using the solvent C provided by the present invention (such as isopropanol and water in Examples 1-6) have better high-temperature, low-temperature and light-illumination stability of mid-infrared (wavelength 4 μm - 16 μm) emissivity and high-temperature, low-temperature and light-illumination stability of near-infrared (wavelength 780 nm - 2000 nm) reflectivity, and have unexpected technical effects.

[0140] (4) Compared with other volume ratios of isopropanol and water in solvent C, the coatings obtained by using the volume ratio of isopropanol and water in solvent C provided by the present invention (such as isopropanol:water (V:V) = 3:2-1:3 in Examples 1-6) have superior high-temperature, low-temperature and light-illumination stability of mid-infrared (wavelength 4 μm - 16 μm) emissivity and high-temperature, low-temperature and light-illumination stability of near-infrared (wavelength 780 nm - 2000 nm) reflectivity, and have unexpected technical effects.

[0141] Experimental Example 3: Ice Cream Melting Test (Insulation Performance Assessment)

[0142] Ice cubes: Water containing blue food-grade pigment was added to ice cream molds and frozen at -20°C for 2 days. The ice cubes were then unmolded and used as ice cubes in this experiment. The initial weight of the ice cubes was approximately 18 grams each.

[0143] Ice cubes of the same mass (approximately 18 g) were placed in cubic glass boxes containing different embodiments of layered colored low emissivity paint, commercial red paint, or no paint, with the same thickness applied to the inner, outer, or both inner and outer surfaces. The bottom of the boxes was insulated with a heat-insulating plate and placed at 24 °C for 1 hour. The mass of the ice cubes that melted was measured, and the results are shown in Table 10.

[0144] Table 10: Thermal Insulation Performance Evaluation

[0145]

[0146] Conclusion: The self-layering colored low emissivity coating provided by this invention is beneficial for heat transfer insulation and has excellent thermal insulation performance.

[0147] The method of this invention has been described through preferred embodiments. Those skilled in the art will readily be able to modify or appropriately alter and combine the methods and applications described herein within the scope, spirit, and context of this invention to implement and apply the technology of this invention. Those skilled in the art can refer to the content herein to appropriately improve process parameters. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included within the scope of this invention.

Claims

1. A self-layering colored low-emissivity coating, characterized in that, include: Low emissivity oil layer dispersion mixture and pigment aqueous layer mixture; The low emissivity oil layer dispersion mixture comprises: flake aluminum powder, solvent A, solvent B and a first binder, wherein solvent A comprises at least one of tetrachloroethylene, dichloromethane, perfluorohexane and 1,1,2,2-tetrachloroethane, solvent B comprises at least one of 1,1,2,2-tetrachloroethane and dichloromethane, and the first binder comprises polyvinyl butyral. The pigment-water mixture comprises: pigment, solvent C, and a second binder, wherein the pigment includes inorganic pigment, the solvent C is isopropanol and water, the volume ratio of isopropanol and water is 3:1 to 1:3, and the second binder is polyvinyl alcohol.

2. The self-layering colored low emissivity coating according to claim 1, wherein solvent A is tetrachloroethylene; and solvent B is 1,1,2,2-tetrachloroethane.

3. In the self-layering colored low emissivity coating according to claim 1, the volume ratio of isopropanol to water is 3:1, 1:1, or 2:

3.

4. The self-layered colored low-emissivity coating according to claim 1, wherein the pigment comprises at least one of Prussian blue, iron oxide, and goethite.

5. The self-layered colored low emissivity coating according to claim 1, wherein the flake diameter of the aluminum powder is 10 μm-120 μm.

6. The self-layering colored low-emissivity coating according to claim 1, wherein each 1g of the flake aluminum powder is mixed with 2.5ml-10ml of solvent A; and / or Each 1g of the first adhesive is mixed with 50ml-150ml of solvent B; and / or The mass ratio of the first adhesive to the flake aluminum powder is 1:20-1:500; and / or The mass ratio of the pigment to the flake aluminum powder is 1:110-50:110; and / or The volume ratio of solvent C to the mass ratio of the pigment is 0.6 ml:1 mg to 0.6 ml:50 mg; and / or The volume ratio of solvent C to the mass of the second adhesive is 0.6 ml:10 mg to 0.6 ml:40 mg.

7. The self-layering colored low-emissivity coating according to claim 1, characterized in that, Solvent A is tetrachloroethylene; solvent B is 1,1,2,2-tetrachloroethane; the first binder is polyvinyl butyral; the pigment includes at least one of Prussian blue, iron oxide, and goethite; solvent C is isopropanol and water; the second binder is polyvinyl alcohol; the volume ratio of isopropanol to water is 3:2-1:3; each g of the flake aluminum powder corresponds to 2.75 ml-10 ml of solvent A; each g of the first binder corresponds to 73 ml-100 ml of solvent B; the mass ratio of the first binder to the flake aluminum powder is 1.5:110-1:100; the mass ratio of the pigment to the flake aluminum powder is 3.3:110-5:110; the volume ratio of solvent C to the mass of the pigment is 0.6 ml:4 mg-0.6 ml:7 mg; the volume ratio of solvent C to the mass of the second binder is 0.6 ml:10 mg-0.6 ml:40 mg.

8. A method for preparing a self-layering colored low-emissivity coating according to any one of claims 1-7, characterized in that, Includes the following steps: (1) Dissolve the first adhesive in solvent B to obtain a first adhesive solution; dissolve the second adhesive in a portion of the formulation amount of solvent C to obtain a second adhesive solution; (2) Mix the flake aluminum powder, the first binder solution and solvent A to obtain the low emissivity oil layer dispersion mixture; (3) Mix the pigment, the second binder solution and the remaining amount of solvent C to obtain the pigment aqueous mixture; (4) Mix the low emissivity oil layer dispersion mixture and the pigment water layer mixture to obtain the self-layered colored low emissivity coating.

9. According to the preparation method of claim 8, the amount of solvent C in step (1) is five-twelfths to ten-twelfths of the formulation amount of solvent C.

10. A low emissivity product or thermal insulation material, characterized in that, The surface is coated with a self-layered colored low emissivity coating as described in any one of claims 1-7 or a self-layered colored low emissivity coating prepared by the preparation method described in any one of claims 8-9.

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