CN113214700A

CN113214700A - Rainproof-mark passive-radiation refrigeration coating, preparation method thereof and coating structure

Info

Publication number: CN113214700A
Application number: CN202110535945.3A
Authority: CN
Inventors: 张卫东; 蔡元柱; 张红强; 李艳稳; 刘联华; 冯雅; 秦杰; 窦枚
Original assignee: China Southwest Architectural Design and Research Institute Co Ltd
Current assignee: China Southwest Architectural Design and Research Institute Co Ltd
Priority date: 2021-05-17
Filing date: 2021-05-17
Publication date: 2021-08-06

Abstract

The invention discloses a rain mark-proof passive radiation refrigeration coating, a preparation method thereof and a coating structure. The paint comprises a rain mark-proof functional synthetic emulsion, a carboxylic acid copolymer polyammonium salt dispersant, hollow glass beads, silicon dioxide, an auxiliary agent and water. The preparation method comprises the step of preparing the rainproof mark passive radiation refrigeration coating through rainproof mark functional synthetic emulsion, carboxylic acid copolymer polyammonium salt dispersant, hollow glass beads, silicon dioxide, an auxiliary agent and water. The rain-proof mark passive radiation refrigeration coating forms a single-layer structure. The invention has the beneficial effects that: the coating has excellent rain mark-proof self-cleaning performance, and the coating can not influence the appearance and reduce the solar reflectivity due to rain marks; the solar reflectivity is not lower than 96.8%; under the direct sunlight at noon in summer, the coating has stronger refrigerating effect that the surface temperature is lower than the ambient temperature than silver-plated non-metallic films and fluorescent and radiation refrigerating coatings.

Description

Rainproof-mark passive-radiation refrigeration coating, preparation method thereof and coating structure

Technical Field

The invention belongs to the technical field of passive radiation refrigeration, and particularly relates to a rain-mark-proof passive radiation refrigeration coating, a preparation method thereof and a coating structure.

Background

The air conditioner active refrigeration technology consumes electric energy, and only discharges heat of buildings and other surfaces needing refrigeration to outdoor space, thereby enhancing the urban heat island effect. In contrast, the radiation refrigeration in the daytime belongs to a passive refrigeration technology, which takes the atmosphere (the temperature of the effective sky is usually lower than the temperature of the near-surface by about 10 ℃) or/and a cold universe space (+3K or-270 ℃) outside the atmosphere as a good radiator, and radiates the heat on the surface to the atmosphere far away from the surface or/and an outer space outside the atmosphere in the form of infrared radiation, so that the passive refrigeration technology has the following advantages: the method is beneficial to saving refrigeration energy consumption in summer, reducing carbon dioxide gas emission caused by burning non-renewable fossil energy for power generation and realizing the national sustainable development strategy of carbon neutralization; and the urban heat island effect and global warming are relieved.

Therefore, since the first experiment in the human scientific history in 2014 successfully observed the passive radiation refrigeration phenomenon that the surface temperature is lower than the ambient temperature in the daytime, especially in the direct sunlight, the passive radiation refrigeration technology in the daytime becomes one of the hottest leading-edge research fields in the world in the last years. However, achieving significant daytime passive radiative cooling places extremely stringent requirements on the optical properties of the surface material as follows: the solar reflectivity of the surface is not lower than 94%, and the higher the reflectivity, the better, the absorption of the surface to solar heat is favorably suppressed to the maximum extent; the surface has good selective infrared radiation at an atmospheric window (8-13 mu m) so as to directly radiate the surface heat to the space in the form of infrared radiation; or high emissivity in the atmospheric window and the entire infrared region outside the atmospheric window to dissipate surface heat as infrared radiation to the cosmonautic space and atmosphere far from the earth's surface.

The existing passive radiation refrigeration technology comprises the following three types: (1) silver plating is carried out on a non-metal substrate such as a silicon crystal plate, lithium fluoride and a high molecular polymer film to improve the solar reflectivity of the surface, and radiation refrigeration in the daytime is realized by utilizing the natural property that the non-metal material has high infrared broad spectrum or selective radiation of an atmospheric window; (2) bleaching wood by a complete delignification method to prepare a structural refrigeration material; (3) and (3) coating materials. However, the surfaces of all three techniques are white.

As a functional exterior wall latex coating, in daytime, like other exterior wall coatings, a passive radiation refrigeration coating has the same effect that a paint film is soaked by rainwater or dew and leaves vertical strip-shaped traces after flowing through, so that uneven surface appearance is caused. The rain mark comprises: in the season of high humidity and easy dew formation or in the season of high humidity and easy occurrence of short-time light rain, hydrophilic or water-soluble organic matters such as an emulsifier, a dispersant and the like in the latex paint film are dissolved out by surface retained water and migrate to the surface of the paint film. When the water is completely volatilized, the water is enriched and separated out on the paint film, and light marks are left; travertine/salt precipitation-induced travertine; staining rain marks and fading rain marks. The presence of these rain marks not only affects the appearance of the coating, but also, for daytime radiation-cooled coatings, reduces the solar reflectance in the rain mark region, causing the daytime radiation-cooled coating to lose its cooling performance.

On the other hand, the effective solar reflectance of the fluorescent and radiation refrigeration coating which is earlier developed by the research and development team is only 94%, although the fluorescent and radiation refrigeration with the surface temperature lower than the ambient temperature can be realized by direct sunlight in daytime, the solar reflectance has a small promotion space, and meanwhile, after the fluorescent refrigeration is introduced, the solar reflectance cannot be directly measured by a standard ultraviolet/visible light/near infrared spectrophotometer due to the interference of fluorescence, only the ground state solar reflectance when the fluorescence is quenched can be measured, and then the contribution of the fluorescence is measured by a light illuminator in combination with an outdoor test, so that the test method is extremely troublesome. Therefore, pure radiation refrigeration coatings with higher solar reflectance have yet to be developed.

Disclosure of Invention

The invention aims to: the invention provides a rain-mark-proof passive radiation refrigeration coating, a preparation method thereof and a coating structure, and solves the problem that the rain mark of the existing coating affects the appearance and the reflectivity. The invention aims to provide a daytime radiation refrigeration coating with solar reflectivity not less than 96.8% and infrared radiance not less than 90%, and the coating has excellent rain mark self-cleaning performance, can completely meet the passive refrigeration requirements of buildings, oil and gas storage tanks, Liquefied Natural Gas (LNG) transport ships, tank cars, cold chain logistics, grain bins, communication base stations, transformer substations, curtains, sunshade umbrellas and other scenes, and can also be applied to infrared camouflage stealth of military grid cloth.

The purpose of the invention is realized by the following technical scheme:

a rain mark-proof passive radiation refrigeration coating comprises a rain mark-proof functional synthetic emulsion, a carboxylic acid copolymer polyammonium salt dispersant, hollow glass beads, silicon dioxide, an auxiliary agent and water.

The refrigeration coating is of a single-layer structure with an integrated bottom surface, and has excellent performance of preventing bright-spot rain marks (snail marks), white rain marks, water white rain marks (white watermarks), pollution rain marks (strip pollution) and fading rain marks. The excellent raindrop-resistant self-cleaning performance is obtained by the following steps: (1) proper emulsion is selected, so that the coating film is internally self-crosslinked in the drying film-forming process, the water penetration is reduced, and the early-stage rain mark resistance of the coating film is improved; (2) hydrophobic modified dispersing agent is used to improve the early rain mark resistance of the coating; (3) and a proper dispersant is added, so that a low-molecular-weight soluble hydrophilic substance can be locked in the drying process of the coating, and a water-soluble substance in the coating is prevented from dissolving out and migrating to the surface of the coating.

The hollow glass beads are used as white pigment, so that the solar scattering area of the surface of the coating can be increased, and the solar reflectivity is improved. The silica can improve the selective infrared radiation of the coating in an atmospheric window so as to improve the infrared radiance of the coating material in the whole infrared region.

Further, the paint comprises, by weight, 10-20 parts of a rain mark-proof functional synthetic emulsion, 1-3 parts of a carboxylic acid copolymer polyammonium salt dispersant, 40-50 parts of hollow glass beads, 10-20 parts of silicon dioxide, 5-10 parts of an auxiliary agent and 10-22 parts of water.

Furthermore, the auxiliary agent comprises a dispersing agent, a wetting agent, a defoaming agent, a flatting agent and a film-forming auxiliary agent.

Further, the paint comprises, by weight, 1-2 parts of a dispersing agent, 1-2 parts of a wetting agent, 1-2 parts of a defoaming agent, 1-2 parts of a leveling agent and 1-2 parts of a film-forming assistant.

Furthermore, the non-radiative heat transfer coefficient in conduction and convection is 5.2-5.25 Wm^-2K^-1In the sunny summer, the aluminum plate coated with the passive radiation refrigerating material for preventing rain marks is coated at the noon time of direct solar radiation, and the surface temperature of the coating is lower than the ambient temperature (7.72 +/-0.49) - (9.87 +/-0.32).

The preparation method of the rain mark-proof passive radiation refrigeration coating comprises the steps of preparing the rain mark-proof passive radiation refrigeration coating through a rain mark-proof functional synthetic emulsion, a carboxylic acid copolymer polyammonium salt dispersant, hollow glass beads, silicon dioxide, an auxiliary agent and water.

Further, mixing the rain mark-proof functional synthetic emulsion, the polycarboxylate ammonium salt dispersant, the hollow glass beads, the silicon dioxide and the auxiliaries except the film-forming auxiliary according to the formula amount, stirring and dispersing at a high speed, adding the film-forming auxiliary according to the formula amount under stirring at a low speed, and dispersing to prepare the rain mark-proof passive radiation refrigeration coating.

A coating structure of the rain-proof mark passive radiation refrigeration coating is characterized in that the rain-proof mark passive radiation refrigeration coating forms a single-layer structure.

Furthermore, the thickness of the single-layer structure is not less than 300 mu m, the solar reflectivity of the coating is 96-97%, and the infrared radiance is not less than 90%.

The invention has the beneficial effects that: the rainproof mark self-cleaning daytime passive radiation refrigeration coating has a single-layer structure on the bottom surface, does not introduce fluorescence refrigeration, and is a single radiation refrigeration coating. Compared with the existing fluorescent and radiation refrigeration coating and other refrigeration coatings, the coating has the following obvious advantages: the coating has excellent rain mark-proof self-cleaning performance, and the coating can not influence the appearance and reduce the solar reflectivity due to rain marks; the solar reflectivity is not less than 96.8 percent, is far higher than the minimum requirement of realizing passive radiation refrigeration in daytime on the solar reflectivity of the surface of the coating not less than 94 percent, is also higher than the solar reflectivity of the existing fluorescent and radiation refrigeration coating, and is equivalent to the solar reflectivity of a silver-plated non-metallic film material; under the direct sunlight at noon in summer, the coating has stronger refrigerating effect that the surface temperature is lower than the ambient temperature than silver-plated non-metallic films and fluorescent and radiation refrigerating coatings.

The main scheme and the further selection schemes can be freely combined to form a plurality of schemes which are all adopted and claimed by the invention; in the invention, the selection (each non-conflict selection) and other selections can be freely combined. The skilled person in the art can understand that there are many combinations, which are all the technical solutions to be protected by the present invention, according to the prior art and the common general knowledge after understanding the scheme of the present invention, and the technical solutions are not exhaustive herein.

Drawings

Fig. 1 is a schematic diagram of the reflectivity of the cold-proof coating for rain marks in example 1 of the present invention at different wavelengths.

FIG. 2 is a schematic diagram of the surface temperature, ambient air temperature and illumination intensity of the aluminum plate at different times of the cold-coating layer for preventing rain marks in example 1 of the present invention.

Fig. 3 is a graph showing the reflectivity of the cold-proof coating for preventing rain marks in example 2 of the present invention at different wavelengths.

Fig. 4 is a schematic diagram of the surface temperature, the ambient air temperature and the illumination intensity of the aluminum plate at different times of the cold-coating layer for preventing rain marks in example 2 of the present invention.

Fig. 5 is a graph showing the reflectivity of the cold-proof coating for rain marks in example 3 of the present invention at different wavelengths.

FIG. 6 is a schematic diagram of the surface temperature, ambient air temperature and illumination intensity of the aluminum plate at different times of the cold-coating layer for preventing rain marks in example 3 of the present invention.

Detailed Description

The following non-limiting examples serve to illustrate the invention.

The prepared white rain mark self-cleaning daytime passive radiation refrigeration coating is coated on a 4cm x 4cm aluminum plate in an airless spraying mode, and the spectral reflectivity, the total solar reflectivity and the infrared emissivity of the coating are respectively measured by an ultraviolet/visible light/near infrared spectrophotometer (Pekin-Elmer Lambda950) and a portable infrared radiance tester (AE1, Devices & Services Co., Dallas, TX).

The prepared white rain-proof mark self-cleaning daytime passive radiation refrigeration coating is coated on an aluminum alloy plate (31cm in length, 31cm in width and 1.0cm in thickness) of a self-built refrigerator in an airless spraying mode, and the ambient temperature is measured by using a thermal resistor placed in a louver box near the refrigerator. The wind speed and the conduction and convection non-radiative heat transfer coefficients are measured by an anemometer, and the solar irradiation intensity is measured by an irradiator. The measured data are transmitted to the computer terminal through wireless.

Example 1

The passive radiation refrigeration coating for preventing rain marks comprises, by weight, 20 parts of a synthetic emulsion with a function of preventing rain marks, 2 parts of a polycarboxylate ammonium salt hydrophobic modified dispersing agent, 50 parts of hollow glass beads, 10 parts of silicon dioxide, 2 parts of a dispersing agent, 2 parts of a wetting agent, 2 parts of a defoaming agent, 1 part of a leveling agent, 1 part of a film forming assistant and 10 parts of water.

The preparation method of the rain-mark-preventing passive radiation refrigeration coating comprises the steps of mixing the rain-mark-preventing functional synthetic emulsion, the polycarboxylate dispersant, the silicon dioxide and the auxiliaries except the film-forming auxiliary according to the formula amount, stirring at a high speed for dispersion, adding the film-forming auxiliary according to the formula amount under low-speed stirring, and preparing the rain-mark-preventing self-cleaning daytime passive radiation refrigeration coating after dispersion.

The rain mark-proof passive radiation refrigeration coating is coated on an aluminum alloy plate of a self-built refrigerator, and the thickness of a dry film of the coating is controlled to be 300 mu m, so that a single-coating structure of the coating can be obtained.

Fig. 1 is a schematic diagram of the reflectivity of the cold-proof coating for preventing rain marks at different wavelengths according to the embodiment of the invention. The total infrared radiance of the rainproof mark self-cleaning daytime passive radiation refrigeration coating is 91%, the total solar reflectivity is 96.9%, and the ultraviolet spectrum reflectivity, the visible light spectrum reflectivity and the near infrared spectrum reflectivity are 95.1%, 98.8% and 94.3% respectively.

Fig. 2 is a schematic diagram of the surface temperature, the ambient air temperature and the illumination intensity of the aluminum plate of the cold-coating layer for preventing rain marks in the embodiment of the invention at different times. It can be seen that during the midday period when sunlight is direct, the heat transfer coefficient when conduction and convection are non-radiative is 4.55Wm^-2K^-1In the case of (2), the surface temperature of the coating layer is constantly lower than the ambient air temperature, and the average value of the lower air temperature is (7.72. + -. 0.49 ℃ C.).

Example 2

The passive radiation refrigeration coating for preventing rain marks comprises, by weight, 15% of a synthetic emulsion with a function of preventing rain marks, 3% of a polycarboxylate ammonium salt hydrophobic modified dispersing agent, 45% of hollow glass beads, 15% of silicon dioxide, 1.4% of a dispersing agent, 1.4% of a wetting agent, 1.4% of a defoaming agent, 1.4% of a leveling agent, 1.4% of a film-forming assistant and 15% of water.

A preparation method and a coating structure of the passive radiation refrigeration coating are the same as those of the embodiment 1.

Fig. 3 is a schematic diagram of the reflectivity of the cold-proof coating for preventing rain marks at different wavelengths according to the embodiment of the invention. The total infrared radiance of the rain-proof mark self-cleaning daytime passive radiation refrigeration coating is 91.5%, the total solar reflectivity is 96.9%, and the ultraviolet spectrum reflectivity, the visible light spectrum reflectivity and the near infrared spectrum reflectivity are 96.9%, 98.9% and 94.2% respectively.

Fig. 4 is a schematic diagram of the surface temperature, the ambient air temperature and the illumination intensity of the aluminum plate of the cold-coating layer for preventing rain marks in the embodiment of the invention at different times. It can be seen that in the noon when the weather is clear and the sunlight is direct, the non-radiative heat transfer coefficient when conduction and convection is 5.247Wm^-2K^-1In the case of (2), the surface temperature of the coating is constantly lower than the ambient air temperature, and the average value of the lower air temperature is (8.01 +/-0.35) DEG C.

Example 3

A rain-mark-proof passive radiation refrigeration coating comprises the following components in parts by weight: 10% of a rain mark-proof functional synthetic emulsion, 1% of a polycarboxylate ammonium salt hydrophobic modified dispersing agent, 40% of hollow glass beads, 20% of silicon dioxide, 1% of a dispersing agent, 1% of a wetting agent, 1% of a defoaming agent, 2% of a leveling agent, 2% of a film-forming assistant and 22% of water.

Fig. 1 is a schematic diagram of the reflectivity of the cold-proof coating for preventing rain marks at different wavelengths according to the embodiment of the invention. The total infrared radiance of the rain-proof mark self-cleaning daytime passive radiation refrigeration coating is 92.3%, the total solar reflectivity is 96.9%, and the ultraviolet spectrum reflectivity, the visible light spectrum reflectivity and the near infrared spectrum reflectivity are 95.1%, 98.5% and 94.3% respectively.

Fig. 2 is a schematic diagram of the surface temperature, the ambient air temperature and the illumination intensity of the aluminum plate of the cold-coating layer for preventing rain marks in the embodiment of the invention at different times. It can be seen that in the noon when the weather is clear and the sunlight is direct, the non-radiative heat transfer coefficient when conduction and convection is 5.2Wm^-2K^-1In the case of (2), the surface temperature of the coating is constantly lower than the ambient air temperature, and the average value of the lower air temperature is (9.87 +/-0.32) DEG C.

The foregoing basic embodiments of the invention and their various further alternatives can be freely combined to form multiple embodiments, all of which are contemplated and claimed herein. In the scheme of the invention, each selection example can be combined with any other basic example and selection example at will. For example, fig. … … can also be regarded as a combination of the basic example and the option … …, fig. … … can also be regarded as a combination of the basic example and the option … …, and so on, which are not exhaustive, and those skilled in the art can recognize many combinations.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. The utility model provides a rain-proof trace passive radiation refrigeration coating which characterized in that: comprises rain mark-proof functional synthetic emulsion, carboxylic acid copolymer polyammonium salt dispersant, hollow glass beads, silicon dioxide, auxiliary agent and water.

2. The rain-mark-proof passive radiation refrigeration coating as claimed in claim 1, wherein: the waterproof paint comprises, by weight, 10-20 parts of a rainproof functional synthetic emulsion, 1-3 parts of a carboxylic acid copolymer ammonium salt dispersant, 40-50 parts of hollow glass beads, 10-20 parts of silicon dioxide, 5-10 parts of an auxiliary agent and 10-22 parts of water.

3. A rain-mark-proof passive radiation refrigeration coating as claimed in claim 1 or 2, characterized in that: the auxiliary agent comprises a dispersing agent, a wetting agent, a defoaming agent, a flatting agent and a film-forming auxiliary agent.

4. A rain-mark resistant passive radiation refrigeration coating as claimed in claim 3, characterized in that: the paint comprises, by weight, 1-2 parts of a dispersing agent, 1-2 parts of a wetting agent, 1-2 parts of a defoaming agent, 1-2 parts of a leveling agent and 1-2 parts of a film-forming assistant.

5. The rain-mark-proof passive radiation refrigeration coating as claimed in claim 1, wherein: the non-radiative heat transfer coefficient in conduction and convection is 5.2-5.25 Wm^-2K^-1In the sunny summer, the aluminum plate coated with the passive radiation refrigerating material for preventing rain marks is coated at the noon time of direct solar radiation, and the surface temperature of the coating is lower than the ambient temperature (7.72 +/-0.49) - (9.87 +/-0.32).

6. A preparation method of the rain-mark-proof passive radiation refrigeration coating as claimed in any one of claims 1 to 5, is characterized in that: the rain mark-proof passive radiation refrigeration coating is prepared from rain mark-proof functional synthetic emulsion, carboxylic acid copolymer polyammonium salt dispersant, hollow glass beads, silicon dioxide, auxiliary agent and water.

7. The method of claim 6, wherein: the auxiliary agent comprises a dispersing agent, a wetting agent, a defoaming agent, a flatting agent and a film-forming auxiliary agent.

8. The production method according to claim 6 or 7, characterized in that: mixing the rain-mark-proof functional synthetic emulsion, the polycarboxylate dispersant, the hollow glass beads, the silicon dioxide and the auxiliaries except the film-forming auxiliary according to the formula amount, stirring and dispersing at a high speed, adding the film-forming auxiliary according to the formula amount under stirring at a low speed, and dispersing to prepare the rain-mark-proof passive radiation refrigeration coating.

9. A coating structure of the rain-mark-proof passive radiation refrigeration coating as claimed in any one of claims 1 to 5, characterized in that: the rain-proof mark passive radiation refrigeration coating forms a single-layer structure.

10. The coating architecture according to claim 9, wherein: the thickness of the single-layer structure is not less than 300 mu m, the solar reflectivity of the coating is 96-97%, and the infrared radiance is not less than 90%.