Hydrophobic radiation refrigeration film suitable for regions with hot summer and cold winter and preparation method of hydrophobic radiation refrigeration film

Abstract

The invention discloses a hydrophobic radiation refrigeration film suitable for regions hot in summer and cold in winter and a preparation method of the hydrophobic radiation refrigeration film. The hydrophobic radiation refrigeration film is prepared from the following components: ultra-high molecular weight polypropylene, high-density polypropylene, methylbenzene, radiation refrigeration functional particles, hydrophobic functional particles and paraffin. Wherein the mass ratio of the ultra-high molecular weight polypropylene to the high-density polypropylene to the paraffin to the radiation refrigeration functional particles to the hydrophobic functional particles is (10-15): (5-10): (60-80): (5-10): (5-10); the hydrophobic radiation refrigeration film is of a three-layer structure, and grids are evenly distributed on each layer of structure. The radiation refrigeration film has efficient reflectivity in the wave band of 300-2500nm, has efficient emissivity in an infrared atmosphere window area (the wavelength is 8-13mu m), has super-hydrophobic capacity and has a contact angle of about 120 degrees with water. Therefore, the film has a good application prospect in hot-summer and cold-winter areas.

Description

Technical Field

[0001] The invention belongs to the field of radiation cooling films, and in particular relates to a hydrophobic radiation cooling film suitable for hot summer and cold winter areas and a preparation method thereof. Background Art

[0002] Global greenhouse gas emissions continue to increase, mainly due to the emission of gases such as carbon dioxide and methane, which has led to the strengthening of the greenhouse effect in the atmosphere and caused global temperature rise. In the past few decades, the surface temperature of the earth has increased by about 1°C, leading to a series of environmental problems such as rising sea levels and melting glaciers. With global warming, extreme weather events such as heavy rains, droughts, and heat waves occur frequently, a large amount of carbon dioxide dissolves in seawater, and the degree of ocean acidification increases, posing a threat to the marine ecosystem, especially the damage to biodiversity such as coral reefs. Therefore, it is particularly important to achieve energy conservation and passive cooling technology.

[0003] Developing passive radiative cooling as a green cooling method can not only save energy to a large extent, but also alleviate the problems of environmental pollution and greenhouse effect caused by traditional refrigeration methods. Radiative cooling is a refrigeration technology that achieves cooling by spontaneously radiating heat to the cold outer space. Radiative cooling can achieve true zero power consumption, no need for refrigerants, zero emission passive cooling, and its maximum cooling power can reach 140-150W / m 2 Because the atmosphere has different transmittances to electromagnetic waves of different wavelengths, and the transmittance in the 8-13 micron band is extremely high, this band is called the "atmospheric window". Therefore, by regulating the spectral properties of the radiation cooling film, it can have the highest possible emissivity in the 8-13 micron band. In order to improve the radiation cooling work, in addition to the high emissivity in the 8-13 micron band, the reflectivity in the 0.3-2.5 micron band should also be as high as possible, so as to achieve high-power radiation cooling per unit area.

[0004] At present, radiant cooling films do not have both radiant cooling and self-cleaning hydrophobic properties. If placed outdoors for a long time, they will be affected by dust, rain, etc., resulting in a decrease in radiant cooling capacity, especially in hot summer and cold winter areas, where there is more rain in summer. Therefore, the hydrophobic function is realized so that rainwater does not stay on the surface of the radiant cooling film. Because of the existence of the hydrophobic function, rainwater can be used to remove dust adhering to the surface, which is particularly important for improving the cooling effect. Summary of the invention

[0005] The present invention proposes a radiation cooling film with a self-cleaning function suitable for areas with hot summers and cold winters and a preparation method thereof. The film has a high reflectivity (>90%) in the solar band (300-2500nm) and a high emissivity (>90%) in the "atmospheric window" (8-13μm) band. It can be prepared by conventional preparation methods and has strong universality.

[0006] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical scheme.

[0007] The present invention provides a hydrophobic radiation refrigeration film suitable for hot summer and cold winter areas, which is prepared by using the following components: ultra-high molecular weight polypropylene (molecular weight range 1×10 6 -1×10 7 ), high-density polypropylene (density range is 0.9-0.915g / cm 3 ), toluene, radiation cooling functional particles, hydrophobic functional particles, paraffin. The hydrophobic radiation cooling film has a three-layer structure, and each layer is provided with a uniformly distributed grid, and the grid structure is used to further increase the hydrophobicity of the film.

[0008] The size of the grid is 1.5 mm×1.5 mm.

[0009] Furthermore, the radiation cooling functional particles include silicon dioxide, titanium dioxide, and aluminum oxide.

[0010] Furthermore, the hydrophobic functional particles include: silicon dioxide and titanium dioxide.

[0011] Furthermore, the diameter of the radiation cooling functional particles is 5nm-20μm.

[0012] Furthermore, the diameter of the hydrophobic functional particles is 5nm-20μm.

[0013] Furthermore, the mass ratio of the ultra-high molecular weight polypropylene, high-density polypropylene, paraffin, radiation refrigeration functional particles, and hydrophobic functional particles is 10-15: 5-10: 60-80: 5-10: 5-10.

[0014] A method for preparing a hydrophobic radiation refrigeration film suitable for hot summer and cold winter areas, comprising the following steps:

[0015] S1: Put paraffin wax, ultra-high molecular weight polypropylene and high-density polypropylene into a sealed beaker heated to 150-300°C and stir for 10-60 minutes at a speed of 100-1000 rpm to mix thoroughly;

[0016] S2. Add the radiation cooling functional particles or the hydrophobic functional particles to the mixture obtained in S1, maintain the temperature at 150-300° C., continue stirring, stir for 10-60 minutes, rotate at 100-1000 rpm, and mix thoroughly;

[0017] S3: transferring the mixture obtained in S2 to a film pressing tool and pressing it into a film. The obtained film has evenly distributed grids, which are specifically formed by extrusion of the film pressing tool. A film pressing tool with a grid of a corresponding size is selected according to the required grid size.

[0018] S4 transfers the membrane obtained in S3 into a toluene solution to extract paraffin in the membrane;

[0019] S5: Apply adhesive to the surface of the object to be radiated and cooled in advance, and cover the surface of the object to be radiated and cooled with the film obtained in S4, and let it stand for 1-10 hours according to different situations until the film is completely cured to obtain the first layer structure;

[0020] S6: After the film is completely solidified, the above S1-S5 process is repeated twice, and the second and third layer structures are covered on the structure obtained in the previous time, so as to obtain a hydrophobic radiation cooling film with a three-layer structure; in the preparation process of the three-layer structure, the functional particles are selected in sequence from silicon dioxide, titanium dioxide, and aluminum oxide.

[0021] Furthermore, based on the above preparation method, a hydrophobic radiation cooling film with a three-layer structure can be formed on the surface of an object requiring radiation cooling for radiation cooling. The hydrophobic radiation cooling film has a thickness of 300-500 μm.

[0022] Furthermore, the adhesive glue is solid double-sided adhesive, liquid spray glue or two-liquid mixed hardening glue.

[0023] Compared with the prior art, the present invention provides a hydrophobic radiation refrigeration film suitable for hot summer and cold winter areas and a preparation method thereof. The film of the present invention uses ultra-high molecular weight polypropylene and high-density polypropylene at the same time, which can fully disperse the functional particles evenly. At the same time, a uniformly distributed grid is designed on the surface of each layer structure to enhance the hydrophobicity of the film, and the grid is conducive to improving the material performance at the scale selected by the present invention. At this time, the hydrophobicity and radiation refrigeration performance of the film are both good. In addition, the present application designs the hydrophobic radiation refrigeration film into a three-layer structure. While each layer of the structure has both radiation refrigeration and hydrophobic properties, the three layers also have a synergistic effect, that is, the top layer of aluminum oxide is used to improve the reflectivity of the ultraviolet band, and the middle layer of titanium dioxide absorbs ultraviolet rays that are not completely reflected, so that the material has the advantage of anti-aging, and improves the durability and practicality of the material in actual working conditions. The bottom layer of silicon dioxide is used to improve the emissivity of the material "atmospheric window" band. The experimental results show that the radiative cooling film provided by the present invention has a high reflectivity in the 300-2500nm band and a high emissivity in the infrared atmospheric window region (wavelength 8-13um), and has super hydrophobicity, with a contact angle with water of about 120°. It can be seen that the film has good application prospects in areas with hot summers and cold winters. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope.

[0025] Figure 1 A flow chart of the technical solution of the method for preparing the radiation refrigeration material proposed in the present invention;

[0026] Figure 2 The present invention is a flow chart of a method for preparing a radiation cooling material according to an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0028] The present invention provides a hydrophobic radiation refrigeration film suitable for hot summer and cold winter areas, which is prepared by using ultra-high molecular weight polypropylene, high-density polypropylene, toluene, radiation refrigeration functional particles, hydrophobic functional particles, and paraffin. The molecular weight range of ultra-high molecular weight polypropylene is 1×10 6 -1×10 7 The density of high-density polypropylene ranges from 0.9 to 0.915 g / cm 3 .

[0029] The radiation cooling functional particles include but are not limited to one or more of silicon dioxide, titanium dioxide, and aluminum oxide.

[0030] The hydrophobic functional particles include but are not limited to one or more of silicon dioxide, titanium dioxide and the like.

[0031] The adhesive glue includes but is not limited to one or more of solid double-sided adhesive, liquid spray adhesive or two-liquid mixed hardening adhesive.

[0032] Example 1

[0033] S1: paraffin wax (72 g), ultra-high molecular weight polypropylene (10 g), and high-density polypropylene (10 g) were placed in a sealed beaker heated to 210° C. and stirred for 50 minutes at a speed of 800 rpm to mix thoroughly;

[0034] S2: Add silica particles (2 μm, 7 g) to S1, maintain the temperature at 210 °C, continue stirring for 50 minutes at a speed of 800 rpm, and mix thoroughly;

[0035] S3 transfers the mixture obtained in S2 to a film pressing tool and presses it into a film. The obtained film has evenly distributed grids; the size of the grids is 1.5 mm×1.5 mm; and the film thickness is about 100 μm.

[0036] S4 transfers the membrane obtained in S3 into a toluene solution, immerses the membrane, and extracts the paraffin in the membrane;

[0037] S5: Apply adhesive to the surface of the object to be radiated and cooled in advance, and cover the film obtained in S4 on the surface of the aluminum plate and let it stand for 5 hours.

[0038] After the film is completely solidified, replace silicon dioxide with titanium dioxide particles (1μm, 7g) and aluminum oxide particles (50nm, 7g), respectively, and repeat the above process to prepare the second and third layer structures. Cover the obtained film (structure) on the surface of the previous film (structure), and finally form a hydrophobic radiation cooling film with a three-layer structure on the object that needs radiation cooling.

[0039] The performance test results of the radiative cooling film prepared in Example 1 are shown in Table 1 below. From the data in the table, it can be seen that the radiative cooling film of the present invention has a high reflectivity in the 300-2500nm band and a high emissivity in the infrared atmospheric window region (wavelength 8-13um), and has super hydrophobicity, and the contact angle with water is about 120°. It can be seen that the film has good application prospects in areas with hot summers and cold winters.

[0040] Table 1 Test results of the film prepared in Example 1

[0041] Example 2

[0042] The difference between this embodiment and embodiment 1 is that the amount of silicon dioxide used is 3 g, and the other processes and amounts remain unchanged.

[0043] Table 2 Test results of the film obtained in Example 2

[0044] Example 3

[0045] The difference between this embodiment and embodiment 1 is that the amount of silicon dioxide used is 10 g, and the other processes and amounts remain unchanged.

[0046] Table 3 Test results of the film obtained in Example 3

Claims

1. A hydrophobic radiation cooling film suitable for hot summer and cold winter areas, characterized by: The ultra-high molecular weight polypropylene is prepared by using the following ingredients: ultra-high molecular weight polypropylene, high-density polypropylene, toluene, radiation cooling functional particles, hydrophobic functional particles, and paraffin. The molecular weight range of the ultra-high molecular weight polypropylene is 1×10 6 -1×10 7 The density of the high-density polypropylene is in the range of 0.9-0.915 g / cm 3 ; Among them, the mass ratio of ultra-high molecular weight polypropylene, high-density polypropylene, paraffin, radiation refrigeration functional particles, and hydrophobic functional particles is: 10-15: 5-10: 60-80: 5-10: 5-10; the hydrophobic radiation refrigeration film has a three-layer structure, and each layer is provided with a uniformly distributed grid.

2. The hydrophobic radiation cooling film suitable for hot summer and cold winter areas according to claim 1, characterized in that: The radiation refrigeration functional particles include silicon dioxide, titanium dioxide and aluminum oxide.

3. The hydrophobic radiative cooling film suitable for hot summer and cold winter areas according to claim 1, characterized in that: The hydrophobic functional particles include silicon dioxide and titanium dioxide.

4. The hydrophobic radiative cooling film suitable for hot summer and cold winter areas according to claim 1, characterized in that: The diameter of the radiation cooling functional particles is 5nm-20μm.

5. The hydrophobic radiative cooling film suitable for hot summer and cold winter areas according to claim 1, characterized in that: The diameter of the hydrophobic functional particles is 5nm-20μm.

6. The hydrophobic radiative cooling film suitable for hot summer and cold winter areas according to claim 1, characterized in that: The thickness of the hydrophobic radiation refrigeration film is 300-500 μm.

7. The method for preparing a hydrophobic radiation refrigeration film suitable for hot summer and cold winter areas according to claim 1, characterized in that: The size of the grid is 1.5 mm×1.5 mm.

8. A method for preparing a hydrophobic radiation refrigeration film suitable for hot summer and cold winter areas according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: placing paraffin wax, ultra-high molecular weight polypropylene, and high-density polypropylene in a sealed container, heating and stirring at 150-300° C. for 10-60 minutes at a speed of 100-1000 rpm, and mixing thoroughly; S2: adding radiation cooling functional particles or hydrophobic functional particles to the mixture obtained in S1, maintaining the temperature at 150-300° C., continuing stirring for 10-60 minutes at a speed of 100-1000 rpm, and mixing thoroughly; S3 transfers the mixture obtained in S2 to a film pressing tool and presses it into a film, wherein the obtained film is provided with evenly distributed grids; S4 transfers the membrane obtained in S3 into a toluene solution to extract paraffin in the membrane; S5: Apply adhesive to the surface of the object to be radiated and cooled in advance, and cover the surface of the object to be radiated and cooled with the film obtained in S4, and let it stand for 1-10 hours until the film is completely cured to obtain the first layer structure; S6 repeats steps S1-S5 twice to obtain a three-layer structure, thereby preparing the hydrophobic radiation refrigeration film; wherein, when preparing the second layer structure and the third layer structure, the difference from preparing the first layer structure is that the second layer structure is covered on the first layer structure, and the third layer structure is covered on the second layer structure; the hydrophobic radiation refrigeration film includes both radiation refrigeration functional particles and hydrophobic functional particles.

9. The method for preparing a hydrophobic radiation refrigeration film suitable for hot summer and cold winter areas according to claim 8, characterized in that: The adhesive glue is solid double-sided adhesive, liquid spray glue or two-liquid mixed hardening glue.

Images