Transmission type radiation refrigeration film
By designing a combination of hollowed-out metal layer and other layers in the radiation refrigeration film, the problem of the existing radiation refrigeration film losing its light transmittance is solved, and a transmissive radiation refrigeration film that maintains the refrigeration effect in scenes where light transmission is required is achieved.
Patent Information
- Application Number
- CN202311366504.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-10-20
- Publication Date
- 2025-04-22
AI Technical Summary
The existing radiation refrigeration film has lost its light transmittance due to the metal layer, and cannot be used in scenarios where light transmittance is required.
A transmissive radiation refrigeration film is designed, including a self-cleaning layer, a base film, a hollow metal layer, a refrigeration layer and a viscose layer. Through the combination of the hollow metal layer and other layers, the transmittance is ensured to be greater than 30% and the haze is less than 2%.
It is achieved to ensure the transmittance and light transmittance of the film while maintaining the refrigeration effect, and can be used in scenarios where light transmittance is required.
Smart Images
Figure CN119860614A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of radiation cooling technology, and in particular to a transmission-type radiation cooling film. Background Art
[0002] Radiative cooling film is a thin film that can regulate temperature. It has the advantages of no energy consumption and no pollution. It is widely used in energy-saving building materials, photovoltaic industry, outdoor products and other fields. Radiative cooling film can use the characteristics of heat-carrying infrared radiation of a specific wavelength to pass through the earth's atmosphere and radiate into space without hindrance, convert unnecessary heat into infrared rays of a specific wavelength, and then reflect the infrared rays into space.
[0003] By setting a metal layer in the radiant cooling film, the cooling effect of the radiant cooling film can be improved. However, the radiant cooling film with a metal layer is not light-transmissive and is limited to use in scenes that do not require light transmission, such as transportation vehicles and cold chains. For scenes that require light transmission, such as glass in buildings, the radiant cooling film cannot be used. Summary of the invention
[0004] The present application provides a transmission type radiation cooling film to solve the problem that the radiation cooling film is not light-transmissive.
[0005] The present application provides a transmission-type radiation cooling film, comprising: a self-cleaning layer, a base film, a metal layer, a cooling layer and an adhesive layer, wherein the base film, the metal layer and the cooling layer are sequentially arranged between the self-cleaning layer and the adhesive layer; when the self-cleaning layer, the base film, the metal layer, the cooling layer and the adhesive layer are stacked, the transmittance is greater than 30% and the haze is less than 2%.
[0006] Optionally, when the thickness of the metal layer is 2nm-35nm, the metal layer is hollowed out or fully set, the hollowed out is set as discontinuous points, and the distance between adjacent points in the discontinuous points is 100μm-200μm.
[0007] Optionally, when the thickness of the metal layer is 35nm-200nm, the metal layer is hollowed out, the hollowed out is discontinuous points, and the distance between adjacent points in the discontinuous points is 100μm-200μm.
[0008] Optionally, when the thickness of the metal layer is 2nm-35nm, a chromium layer is further provided between the metal layer and the base film.
[0009] Optionally, the self-cleaning layer is a polymer containing silicon or fluorine and / or the self-cleaning layer is provided with a micro-nano structure, and the micro-nano structure includes protrusions and depressions distributed at intervals. By adding a polymer containing silicon or fluorine to the self-cleaning layer and providing the micro-nano structure, the self-cleaning layer has the functions of being hydrophobic and anti-fouling and improving the radiation cooling effect.
[0010] Optionally, the base film is any one or more combinations of PET, PVC, PC, PP, PE, PMMA, and TPU, and the base film thickness is 23 μm-200 μm. By selecting the base film to be any one or more combinations of PET, PVC, PC, PP, PE, PMMA, and TPU, the self-cleaning layer and the metal layer can be respectively provided on both sides of the base film without affecting the transmittance of the transmission-type radiation cooling film.
[0011] Optionally, the metal layer is a combination of one or more of aluminum, silver, titanium, copper, and nickel. By providing the metal layer, the cooling effect of the transmission-type radiation cooling film can be improved. Optionally, the cooling layer is formed by coating a coating mixed with a filler, and the filler is at least one or more of a combination of silicon dioxide and glass microbeads, and the filler particle diameter is 15μm-50μm. By coating silicon dioxide and glass microbeads on the surface of the metal layer, the radiation energy can be concentrated in the infrared band to achieve infrared radiation.
[0012] Optionally, the adhesive layer is a self-adhesive adhesive with a thickness of 20 μm-50 μm. By setting the adhesive layer to be a self-adhesive adhesive with a thickness of 20 μm-50 μm, the transmission-type radiation cooling film can be adhered to the target object, and the self-adhesive adhesive will not lose its adhesiveness due to water loss.
[0013] Optionally, the adhesive layer further includes an infrared absorber and an ultraviolet absorber, and the ratio of the adhesive, the infrared absorber and the ultraviolet absorber is adhesive: infrared absorber: ultraviolet absorber = 1: 0.5-3: 0.1-3. By adding the infrared absorber and the ultraviolet absorber to the adhesive, light in other wavelengths other than visible light can be absorbed and then radiated out through the cooling layer.
[0014] It can be seen from the above technical scheme that the present application provides a transmission type radiation cooling film, comprising: a self-cleaning layer, a base film, a metal layer, a cooling layer and an adhesive layer, wherein the base film, the metal layer and the cooling layer are sequentially arranged between the self-cleaning layer and the adhesive layer; when the self-cleaning layer, the base film, the metal layer, the cooling layer and the adhesive layer are stacked, the transmittance is greater than 30% and the haze is less than 2%. By setting the transmittance of the base film, the metal layer, the cooling layer and the adhesive layer to be greater than 30% when stacked, the problem of the radiation cooling film being opaque can be solved. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] In order to more clearly illustrate the technical solution of the present application, the drawings required for use in the embodiments are briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.
[0016] Figure 1 A schematic diagram of the structure of a transmission-type radiation cooling film provided in an embodiment of the present application;
[0017] Figure 2 A schematic diagram of another transmission-type radiation cooling film structure provided in an embodiment of the present application;
[0018] Figure 3 This is a comparison chart of the sunlight transmittance of the transmission-type radiation cooling film and the PET film provided in the embodiments of the present application.
[0019] Reference numerals:
[0020] Among them, 1-self-cleaning layer; 2-base film; 3-metal layer; 4-refrigeration layer; 5-adhesive layer; 6-chromium layer. DETAILED DESCRIPTION
[0021] The following embodiments are described in detail, and examples thereof are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementations described in the following embodiments do not represent all implementations consistent with the present application. They are only examples of systems and methods consistent with some aspects of the present application as detailed in the claims.
[0022] Radiative cooling film is a film that can regulate temperature. It has the advantages of no energy consumption and no pollution. It is widely used in energy-saving building materials, photovoltaic industry, outdoor products and other fields. Radiative cooling film can utilize the property that heat-carrying infrared radiation of a specific wavelength can pass through the earth's atmosphere unimpeded and radiate into space, convert unnecessary heat into infrared rays of a specific wavelength, and then reflect the infrared rays into space. By providing the metal layer 3 in the radiative cooling film, the cooling effect of the radiative cooling film can be improved. However, the radiative cooling film provided with the metal layer 3 is not light-transmitting and is limited to use in scenes where light transmission is not required, such as transportation vehicles and cold chains. For scenes that require light transmission, such as glass in buildings, radiative cooling film cannot be used.
[0023] To solve the problem of radiation cooling film opacity, see Figure 1 , Figure 1The schematic diagram of the structure of the transmission type radiation cooling film provided in the embodiment of the present application includes: a self-cleaning layer 1, a base film 2, a metal layer 3, a cooling layer 4 and an adhesive layer 5, wherein the base film 2, the metal layer 3 and the cooling layer 4 are sequentially arranged between the self-cleaning layer 1 and the adhesive layer 5; when the self-cleaning layer 1, the base film 2, the metal layer 3, the cooling layer 4 and the adhesive layer 5 are stacked, the transmittance is >30%, and the haze is <2%. When the thickness of the metal layer is 2nm-35nm, the metal layer is hollowed out or fully arranged, and the hollowing is arranged as discontinuous points, and the spacing between adjacent points in the discontinuous points is 100μm-200μm. When the thickness of the metal layer is 35nm-200nm, the metal layer is hollowed out, and the hollowing is arranged as discontinuous points, and the spacing between adjacent points in the discontinuous points is 100μm-200μm.
[0024] It can be understood that transmittance is the ratio of the radiation energy projected and transmitted through the object to the total radiation energy projected onto the object during the process of the incident light flux leaving from the illuminated surface or the incident surface of the medium to the other side. Haze is a cloud state caused by light scattering inside or on the surface of a transparent or translucent object.
[0025] The self-cleaning layer 1 is embossed on one side of the base film 2 by coating, the metal layer 3 is arranged on the other side of the base film 2, and then the cooling layer 4 and the adhesive layer 5 are arranged in sequence, and the radiation cooling effect is achieved by the metal layer 3 and the adhesive layer 5, and the transmittance of the metal layer 3 is increased by hollowing out discontinuous points, so that the transmittance of the self-cleaning layer 1, the base film 2, the metal layer 3, the cooling layer 4, and the adhesive layer 5 when stacked together is greater than 30%, so that the radiation cooling film with the metal layer 3 can be used in scenes where light transmission is required.
[0026] In some embodiments, the self-cleaning layer 1 is a polymer containing silicon or fluorine, and the self-cleaning layer 1 is provided with a micro-nano structure, and the micro-nano structure includes convex parts and concave parts distributed at intervals. The self-cleaning layer 1 has the functions of being hydrophobic and anti-fouling and improving the radiation cooling effect.
[0027] In some embodiments, the base film 2 is any one or more combinations of PET (polyethylene terephthalate), PVC (polyvinyl chloride), PC (polycarbonate), PP (polypropylene), PE (polyethylene), PMMA (polymethyl methacrylate), TPU (thermoplastic polyurethane elastomer), and the thickness of the base film 2 is 23 μm-100 μm. One side of the base film 2 is coated and embossed to obtain the self-cleaning layer 1, and the other side of the base film 2 is connected to the metal layer 3, while not affecting the transmittance of the transmission-type radiation cooling film.
[0028] In some embodiments, the thickness of the metal layer 3 is 2nm-200nm. In metals, since there are free electrons in the metal, the free electrons are not bound by the nucleus. When light propagates to the metal surface, the free electrons will be forced to vibrate under the action of its electric field, and then produce vibrations with the same frequency as the incident light, and this vibration emits light with the same frequency as the original light. Among them, when the thickness of the metal layer 3 is less than the mean free path of the free electrons in the metal layer 3, the mean free path increases as the thickness of the metal layer 3 increases. Therefore, by setting the metal layer 3, the cooling effect of the transmission-type radiation cooling film can be improved.
[0029] In some embodiments, the metal layer 3 is one or more combinations of aluminum, silver, titanium, copper, and nickel. For example, the metal layer 34 is aluminum, which is a good thermal insulation material. The thermal insulation of aluminum is mainly reflected in the thermal radiation performance of aluminum. Aluminum is a metal with a strong ability to reflect sunlight. When the thickness of the aluminum layer is less than 35nm, the transmittance of the aluminum layer decreases with the increase of thickness, and the reflectivity increases with the increase of thickness. When the thickness of the aluminum layer is greater than 35nm, the transmittance of the aluminum layer is close to zero. As the thickness increases, the reflectivity increases sharply. When the thickness is greater than the mean free path of the electrons in the aluminum layer, the reflectivity no longer increases with the increase of thickness. Therefore, aluminum is used as the material of the metal layer 34, and the influence of the thickness of the metal layer 34 on the reflectivity and weight is comprehensively considered. In some embodiments, when the thickness of the metal layer is 2nm-35nm, the metal layer is hollowed out or fully set, and the hollowing is set as discontinuous points, and the distance between adjacent points in the discontinuous points is 100μm-200μm. When the thickness of the metal layer is 35nm-200nm, the metal layer is hollowed out, and the hollowing is set as discontinuous points, and the distance between adjacent points in the discontinuous points is 100μm-200μm. When the thickness of the metal layer is 2nm-35nm, a chromium layer is also provided between the metal layer and the base film. That is, when the thickness of the aluminum layer is less than 35nm, the metal layer 3 may be hollowed out, or it may not be hollowed out, and when the thickness of the aluminum layer is less than 35nm, the aluminum layer has a certain transmittance. Therefore, when the self-cleaning layer 1, the base film 2, the metal layer 3, the refrigeration layer 4 and the adhesive layer 5 are stacked together, and the transmittance is greater than 30%, the aluminum layer can be set globally. When the thickness of the aluminum layer is greater than 35nm, since the transmittance of the aluminum layer is close to zero, although the aluminum layer has a good reflectivity, it cannot meet the transmission requirements. Therefore, according to the principle that light can be transmitted to the human eye through a certain density of dot matrix, the aluminum layer can be hollowed out to set discontinuous points, and the spacing between adjacent discontinuous points can be set to 100μm-200μm, or it can be a continuous line. By setting the ratio of blocking and non-blocking, the aluminum layer can meet the cooling requirements while also being transparent. In addition, the dot matrix can be used to customize the pattern to improve the visual effect and anti-peeping effect of the transmission-type radiation cooling film.
[0030] It is understandable that the thickness of the metal layer 34 is 10nm-200nm. For example, aluminum is selected as the metal layer 34, and the thickness can be any one of 10nm, 11nm, ..., 200nm. When the thickness of the metal layer 3 exceeds 35nm, the transmittance of the metal layer 3 is close to zero. Therefore, when the thickness of the metal layer 3 exceeds 35nm, the light-transmitting effect of the metal layer 3 can be achieved through discontinuous points or continuous lines. When the thickness of the metal layer 3 is less than 35nm, the metal layer 3 has a certain transmittance. When the self-cleaning layer 1, the base film 2, the metal layer 3, the refrigeration layer 4, and the adhesive layer 5 are stacked together, the transmittance is greater than 30%, and the metal layer 3 does not need to be hollowed out. When the thickness of the metal layer 3 is greater than 35nm, since the metal layer is thick and opaque, there is no need to set a chromium layer.
[0031] like Figure 2 As shown, in some embodiments, when the thickness of the metal layer 3 is less than 35 nm, the chromium layer 6 is further provided between the metal layer 3 and the base film 2. When the thickness of the metal layer 3 is less than 35 nm, the metal layer 3 has a certain transmittance, but the chromium layer 6 needs to be provided between the metal layer 3 and the base film 2. By adding the chromium layer 6, the chromium layer 6 absorbs light in the ultraviolet and infrared bands, thereby improving the cooling effect.
[0032] In some embodiments, the refrigeration layer 4 is formed by coating with a coating mixed with a filler, and the filler is at least one or more combinations of silicon dioxide and glass microspheres, and the filler particle diameter is 15μm-50μm. After mixing one or more of silicon dioxide and glass microspheres, they are coated on one side of the base film 2 in the principle of the metal layer 3. Among them, the glass microsphere is a hollow glass microsphere with a smooth surface at the micrometer level, and the main chemical component is borosilicate glass. It is a hollow transparent positive sphere observed under an electron microscope. The glass microsphere has a variety of properties such as low density, high strength, high temperature resistance, acid and alkali resistance, low thermal conductivity, and electrical insulation, and has good fluidity and chemical stability. The average particle size of the hollow glass microsphere is only tens of micrometers, and the air inside cannot flow freely, making convection heat transfer difficult to occur, leaving only the heat conduction of still air, and the thermal conductivity of still air is low, and the heat conducted through the air inside the hollow glass microsphere is less. Therefore, the filler is set as glass microspheres, which can make the refrigeration layer 4 have many reflective interfaces, thereby reducing radiative heat conduction, increasing thermal impedance, and reducing heat transfer efficiency.
[0033] In addition, the internal structure of silicon dioxide is composed of cross-linked nanoparticles, which are connected into a skeleton to form a unique mesh porous structure with a pore size between 15nm and 50nm. By using silicon dioxide to form the cooling layer 4, heat conduction can be suppressed, heat convection can be blocked, and heat radiation can be blocked, thereby blocking heat transfer in all directions and having an extremely low thermal conductivity. The cooling layer 4 is formed by mixing silicon dioxide and glass beads and coating them to enhance the cooling effect.
[0034] In some embodiments, the adhesive layer 5 is a self-adhesive adhesive, and the thickness of the adhesive layer 5 is 20 μm-50 μm. The thickness of the adhesive layer 5 is 20 μm-50 μm, and the adhesive layer 5 can adhere the transmission type radiation cooling film to the object that needs to be cooled, forming a strong mechanical and chemical bond between the transmission type radiation cooling film and the object. The adhesive layer 5 also has the functions of high temperature resistance, oxidation resistance, UV radiation resistance and solvent resistance, and can have strong viscosity at room temperature.
[0035] In some embodiments, the adhesive layer 5 further includes an infrared absorber and an ultraviolet absorber, and the ratio of the adhesive, the infrared absorber and the ultraviolet absorber is adhesive: infrared absorber: ultraviolet absorber = 1: 0.5-3: 0.1-3. In order to improve the refrigeration effect of the transmission type radiation refrigeration film, an infrared absorber and an ultraviolet absorber can be added to the adhesive, the ultraviolet absorber can absorb 200nm-400nm light, and the infrared absorber is used to absorb 800nm-2500nm. 0.5-3 infrared absorbers and 0.1-3 ultraviolet absorbers are added to the adhesive. By adding infrared absorbers and ultraviolet absorbers to the adhesive layer 5, light in other bands except visible light can be absorbed and then radiated out through the refrigeration layer 4 to achieve the absorption of non-visible light and improve the refrigeration effect.
[0036] like Figure 3 As shown, Figure 3 This is a comparison chart of the sunlight transmittance between the transmission type radiation cooling film and the PET film. Figure 3 It can be seen that the transmittance of the transmission type radiation cooling film to ultraviolet light is close to zero in the sunlight band of 200nm-400nm, and the transmittance of the transmission type radiation cooling film to infrared light in the sunlight band of 780nm-2500nm is also much lower than the transmittance of the PET film to infrared light. Therefore, the transmission type radiation cooling film can block most of the light in the ultraviolet and infrared bands, and reduce the heat generated by light in other bands except visible light. At the same time, the transmittance in the sunlight band of 400nm-780nm is greater than 30%. Therefore, the transmission type radiation cooling film provided in the embodiment of the present application does not affect the transmittance in the visible light region.
[0037] In some embodiments, the performance test of the transmission type radiation cooling film mainly includes the effect of adding ultraviolet absorber and infrared absorber on the transmittance. As shown in Table 1:
[0038] Table 1: Transmittance comparison test
[0039]
[0040] As shown in Table 1, when no ultraviolet absorber and infrared absorber are added, the transmittance in the ultraviolet region and infrared region is 15% and 35%, and after adding the ultraviolet absorber and infrared absorber, the transmittance in the ultraviolet region and infrared region is 0% and 15%. It can be seen that after adding the ultraviolet absorber and infrared absorber, the adhesive layer can completely isolate the ultraviolet light band, and the infrared light band can also be greatly reduced. Therefore, after adding the ultraviolet absorber and infrared absorber, the adhesive layer can absorb non-visible light and improve the cooling effect. At the same time, after adding the ultraviolet absorber and infrared absorber, the impact on the visible light region is small, and the light transmittance of the transmission type radiation cooling film is not affected.
[0041] It can be seen from the above technical scheme that the present application provides a transmission type radiation cooling film, comprising: a self-cleaning layer 1, a base film 2, a metal layer 3, a cooling layer 4 and an adhesive layer 5, wherein the base film 2, the metal layer 3 and the cooling layer 4 are sequentially arranged between the self-cleaning layer 1 and the adhesive layer 5; when the self-cleaning layer 1, the base film 2, the metal layer 3, the cooling layer 4 and the adhesive layer 5 are stacked, the transmittance is greater than 30% and the haze is less than 2%. By setting the transmittance greater than 30% when the base film 2, the metal layer 3, the cooling layer 4 and the adhesive layer 5 are stacked, the problem of the radiation cooling film being opaque can be solved.
[0042] Similar parts between the embodiments provided in this application can be referenced to each other. The specific implementation methods provided above are only a few examples under the general concept of this application and do not constitute a limitation on the protection scope of this application. For those skilled in the art, any other implementation methods expanded based on the scheme of this application without creative work belong to the protection scope of this application.
Claims
1. A transmission type radiation cooling film, characterized in that: include: A self-cleaning layer (1), a base film (2), a metal layer (3), a refrigeration layer (4) and an adhesive layer (5), wherein the base film (2), the metal layer (3) and the refrigeration layer (4) are sequentially arranged between the self-cleaning layer (1) and the adhesive layer (5); when the self-cleaning layer (1), the base film (2), the metal layer (3), the refrigeration layer (4) and the adhesive layer (5) are stacked, the transmittance is greater than 30% and the haze is less than 2%.
2. The transmission type radiation cooling film according to claim 1, characterized in that: When the thickness of the metal layer (3) is 2nm-35nm, the metal layer (3) is hollowed out or fully set, the hollowed out is set as discontinuous points, and the distance between adjacent points in the discontinuous points is 100μm-200μm.
3. The transmission type radiation cooling film according to claim 1, characterized in that: When the thickness of the metal layer (3) is 35 nm-200 nm, the metal layer (3) is hollowed out, the hollowed out portions are discontinuous points, and the distance between adjacent points in the discontinuous points is 100 μm-200 μm.
4. The transmission type radiation cooling film according to claim 1, characterized in that: When the thickness of the metal layer is 2nm-35nm, a chromium layer (6) is further provided between the metal layer (3) and the base film (2).
5. The transmission type radiation cooling film according to claim 1, characterized in that: The self-cleaning layer (1) is a polymer containing silicon or fluorine and / or the self-cleaning layer (1) is provided with a micro-nano structure, wherein the micro-nano structure comprises protrusions and depressions distributed at intervals.
6. The transmission type radiation cooling film according to claim 1, characterized in that: The base film (2) is any one or more combinations of PET, PVC, PC, PP, PE, PMMA, and TPU, and the thickness of the base film (2) is 23 μm-200 μm.
7. The transmission type radiation cooling film according to claim 1, characterized in that: The metal layer (3) is one or a combination of aluminum, silver, titanium, copper and nickel.
8. The transmission type radiation cooling film according to claim 1, characterized in that: The cooling layer (4) is formed by coating a coating mixed with a filler, wherein the filler is at least one or a combination of silicon dioxide and glass microbeads, and the filler particle diameter is 15 μm-50 μm.
9. The transmission type radiation cooling film according to claim 1, characterized in that: The adhesive layer (5) is a self-adhesive adhesive and has a thickness of 20 μm-50 μm.
10. The transmission type radiation cooling film according to claim 9, characterized in that: The adhesive layer (5) further comprises an infrared absorber and an ultraviolet absorber, and the ratio of the self-adhesive sticker, the infrared absorber and the ultraviolet absorber is self-adhesive sticker: infrared absorber: ultraviolet absorber = 1: 0.5-3: 0.1-3.