Passive cooling radiation refrigeration light-transmitting film and preparation method thereof

Abstract

The invention relates to the field of energy-saving and environment-friendly new materials, in particular to a passive cooling radiation refrigeration light-transmitting film and a preparation method thereof. Comprising a first release protective film layer, a back adhesive layer, a first base material film layer, a second base material film layer, an IR reflecting layer, an IR selective emitting layer, a third base material film layer, a self-cleaning and self-repairing functional coating and a second release protective film layer which are sequentially stacked. The passive cooling radiation refrigeration light-transmitting film provided by the invention is moderate in thickness, strong in flexibility and large in stretchability, and can be tightly attached to any surface part. Under the condition that the appearance color is not influenced, the visible light wave band transmittance is greater than 70%, the infrared light reflectivity is greater than 68%, the 8-13 [mu] m atmosphere window emissivity is greater than 97%, the radiation refrigeration power is greater than 140 W / m < 2 >, and the heat insulation performance is good; as the used base material is TPU or PET, the tensile property is large, the flexibility is strong, and the product has good flexibility and contractibility, and is not easy to wrinkle and blister during film pasting construction.

Description

Technical Field

[0001] The present invention relates to the field of new energy-saving and environmental protection materials, and particularly to a radiative cooling and light-transmitting film with passive cooling and a preparation method thereof. Background Art

[0002] The management of the temperature inside an automobile or a building has always been a key issue in design and user experience. Especially in the hot summer, the temperature inside an automobile or a building can quickly rise to an uncomfortable level. Traditional window films mainly reduce the heat inside the vehicle by increasing the solar reflectance. However, this method often affects the light-transmitting performance of the glass window, resulting in limited visibility and may also affect the overall appearance. In addition, the efficiency of traditional window films in reducing temperature may not be ideal. Especially when the glass window is heated after being exposed to sunlight for a long time, internal secondary thermal radiation will be generated.

[0003] Therefore, those skilled in the art have provided a radiative cooling and light-transmitting film with passive cooling and a preparation method thereof to solve the problems raised in the above background art. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a radiative cooling film with passive cooling and a preparation method thereof. By designing the material layer structure, the problem in the prior art that although the heat insulation film can reduce temperature and heat insulation to a certain extent, it cannot solve the problems of secondary thermal radiation of glass and light-transmitting effect is solved.

[0005] A radiative cooling film with passive cooling includes a first release protective film layer, an adhesive layer, a first substrate film layer, a second substrate film layer, an IR reflection layer, an IR selective emission layer, a third substrate film layer, a self-cleaning and self-healing functional coating, and a second release protective film layer, which are sequentially stacked.

[0006] Preferably, the IR reflection layer includes a metal reflection layer and a metal / metal oxide protective layer that are alternately stacked in sequence.

[0007] Preferably, the number of layers of the metal / metal oxide protective layer is one more than the number of layers of the metal reflection layer, and its function is to improve the infrared reflectance of the entire radiative cooling film.

[0008] Preferably, the number of layers of the IR reflection layer is 3 - 7 layers.

[0009] Preferably, the thickness of the IR reflection layer is 15 - 250 nm.

[0010] Preferably, the material of the metal reflection layer in the IR reflection layer is selected from at least one of Al, Ag, and Au, and the material of the metal / metal oxide protective layer is selected from one or more of Ti, Nb, TiO 2 , NbO.

[0011] Preferably, the IR selective emission layer is a polymer resin layer with radiation cooling functional nanoscale ceramic particles uniformly dispersed therein; The radiation cooling functional nanoscale ceramic particles are selected from at least one of TiO 2 , Al 2 O 3 , SiO 2 , Si 3 N 4 , BaSO 4 , SiOxNy (where x is between 0.1 and 2, and y is between 0.1 and 2). The ceramic particles are bonded to the ceramic IR selective emission layer by chemical bonding, physical bonding, or a combination of chemical bonding and physical bonding. The average particle spacing of the ceramics is 0.5 - 1.5 times the average particle diameter of the ceramic particles. Each ceramic particle can be solid or hollow, with an average emissivity between 0.5 and 1, a particle diameter less than 100 nm, and the thickness of the IR selective emission layer is 1 - 50 μm.

[0012] Preferably, the thickness of the self - cleaning and self - repairing functional coating is 1 - 10 μm.

[0013] Preferably, the first / second release protective film layer is a PET film with a thickness of 20 - 100 μm.

[0014] Preferably, the first substrate film layer and the third substrate film layer are independently TPU films with a thickness of 50 - 100 μm.

[0015] Preferably, the pressure - sensitive adhesive layer is a pressure - sensitive adhesive with a thickness of 3 - 25 μm.

[0016] Preferably, the second substrate film layer is a PET film with a thickness of 3 - 23 μm.

[0017] This film has the following technical characteristics: the visible light band transmittance is greater than 70%; the near - infrared light reflectance is greater than 68%; the emissivity in the 8 - 13 μm atmospheric window is greater than 97%; the radiation cooling power is greater than 140 W / m².

[0018] A preparation method of a passive - cooling radiation cooling film includes the following steps: Step 1: After coating a pressure - sensitive adhesive on one side of the first substrate film layer, the first release protective film layer is laminated with the first base film layer; Step 2: On the side of the first substrate film layer facing away from the first release protective film layer, the first substrate film layer is adhered; Step 3: On the side of the second substrate film layer facing away from the first substrate film layer, a metal / metal oxide is sputtered to form an IR reflection layer; Step 4: On the side of the IR reflective layer facing away from the second substrate film layer, coat a polymer resin containing radiation cooling functional nanoscale ceramic particles to form an IR selective emission layer; Step 5: On the side of the IR selective emission layer facing away from the IR reflective layer, bond the third substrate film layer; Step 6: On the side of the third substrate film layer facing away from the IR selective emission layer, coat a self-cleaning and self-repairing coating; Step 7: On the side of the self-cleaning and self-repairing coating facing away from the third substrate film layer, bond the second release protective film layer.

[0019] Technical effects and advantages of the present invention: The passive cooling radiation cooling transparent film provided by this application has a moderate thickness, strong flexibility, and large stretchability, and can be closely attached to any surface part. Without affecting the appearance color, it has a visible light band transmittance of more than 70%, an infrared light reflectivity of more than 68%, an 8 - 13um atmospheric window emissivity of more than 97%, and a radiation cooling power of more than 140W / m 2 . It has good heat insulation performance; since the substrate used is TPU or PET, it has large stretchability, strong flexibility, and the product has good flexibility and shrinkage, and it is not easy to wrinkle or blister during the film application construction. And the production and preparation process of the passive cooling radiation cooling transparent film product provided by this application is simple, the firmness of metal material sputtering on the substrate surface can be effectively controlled, and any stretching during preparation will not affect the appearance and heat insulation effect. Brief Description of the Drawings

[0020] Figure 1 It is a system structure diagram of a passive cooling radiation cooling transparent film provided by an embodiment of this application. Detailed Embodiments

[0021] The present invention will be further described in detail below in conjunction with the drawings and specific embodiments. The embodiments of the present invention are given for the purpose of illustration and description, and are not exhaustive or limited to the disclosed form. Many modifications and variations are obvious to those of ordinary skill in the art. The embodiments are selected and described to better illustrate the principles and practical applications of the present invention, and enable those of ordinary skill in the art to understand the present invention and thus design various embodiments with various modifications suitable for specific purposes. Embodiment

[0022] Please refer to Figure 1 , in this embodiment, a passive cooling radiation cooling transparent film and its preparation method are provided, including A passive cooling radiative cooling transparent film, comprising a first release protective film layer, an adhesive layer, a first substrate film layer, a second substrate film layer, an IR reflective layer, an IR selective emission layer, a third substrate film layer, a self-cleaning and self-healing functional coating, and a second release protective film layer, which are sequentially stacked.

[0023] The IR reflective layer includes a metal reflective layer and a metal / metal oxide protective layer that are alternately stacked in sequence.

[0024] The number of layers of the metal / metal oxide protective layer in the IR reflective layer is 1 more than the number of layers of the metal reflective layer.

[0025] The function of the IR reflective layer is to improve the infrared reflectivity of the entire radiative cooling film.

[0026] The number of layers of the IR reflective layer is 3 to 7 layers.

[0027] The thickness of the IR reflective layer is 15 to 250 nm.

[0028] In the IR reflective layer, the material of the metal reflective layer is selected from at least one of Al, Ag, and Au.

[0029] In the IR reflective layer, the material of the metal / metal oxide protective layer is selected from one or more of Ti, Nb, TiO2, and NbO.

[0030] The IR selective emission layer is a polymer resin layer in which radiative cooling functional nanoscale ceramic particles are uniformly dispersed inside.

[0031] The radiative cooling functional nanoscale ceramic particles are selected from at least one of TiO 2 , Al 2 O 3 , SiO 2 , Si 3 N 4 , BaSO 4 , and SiOxNy.

[0032] For the radiative cooling functional nanoscale ceramic particles, x in SiOxNy is between 0.1 and 2, and y in SiOxNy is between 0.1 and 2.

[0033] For the radiative cooling functional nanoscale ceramic particles, the ceramic particles are bonded to the ceramic IR selective emission layer by chemical bonding, physical bonding, or a combination of chemical bonding and physical bonding.

[0034] The average particle spacing is 0.5 to 1.5 times the average particle diameter of the ceramic particles.

[0035] Each ceramic particle is solid or hollow.

[0036] The average emissivity of the radiative cooling functional nanoscale ceramic particles is between 0.5 and 1.

[0037] The particle size of the radiative cooling functional nanoscale ceramic particles is less than 100 nm.

[0038] The thickness of the IR selective emission layer is 1 - 50 μm.

[0039] The thickness of the self - cleaning and self - repairing functional coating is 1 - 10 μm.

[0040] The first / second release protective film layer is a PET film with a thickness of 20 - 100 μm.

[0041] The first substrate film layer and the third substrate film layer are independently TPU films with a thickness of 50 - 100 μm.

[0042] The pressure - sensitive adhesive layer is a pressure - sensitive adhesive with a thickness of 3 - 25 μm.

[0043] The second substrate film layer is a PET film with a thickness of 3 - 23 μm.

[0044] The radiative cooling and light - transmissive thin film for passive cooling includes the following technical features: The visible - light band transmittance is greater than 70%; The near - infrared light reflectance is greater than 68%; The emissivity in the 8 - 13 μm atmospheric window is greater than 97%; The radiative cooling power is greater than 140 W / m 2 。

[0045] According to another aspect of the present application, there is also provided a method for preparing the above - mentioned radiative cooling and light - transmissive thin film for passive cooling, which is characterized by including the following steps: Step 1: After coating a pressure - sensitive adhesive on one side of the first substrate film layer, the first release protective film layer is laminated with the first base film layer; Step 2: On the side of the first substrate film layer facing away from the first release protective film layer, the first substrate film layer is adhered; Step 3: On the side of the second substrate film layer facing away from the first substrate film layer, a metal / metal oxide is sputtered to form an IR reflection layer; Step 4: On the side of the IR reflection layer facing away from the second substrate film layer, a polymer resin containing radiative cooling functional nanoscale ceramic particles is coated to form an IR selective emission layer; Step 5: On the side of the IR selective emission layer facing away from the IR reflection layer, the third substrate film layer is adhered; Step 6: On the side of the third substrate film layer facing away from the IR selective emission layer, a self - cleaning and self - repairing coating is coated; Step 7: Bond the second release protective film layer to the side of the self-cleaning and self-repairing coating that faces away from the third base film layer.

[0046] The above-mentioned radiative cooling and light-transmitting film for passive cooling can be pasted on the surface of an automobile or a building to improve the heat insulation performance of the automobile or the building and prevent a large amount of heat from being transferred into the automobile or the building under sunlight exposure.

[0047] When this solution is in use: The preparation steps of the film are as follows: Composite adhesive layer: Prepare a first base film layer (TPU film) with a thickness of 50-100 μm, evenly coat a pressure-sensitive adhesive with a thickness of 3-25 μm on one side as the adhesive layer, and then laminate the first release protective film layer (PET film) with a thickness of 20-100 μm to the first base film layer coated with the adhesive layer to ensure close adhesion and no air bubbles.

[0048] Form an IR reflection layer: Select a second base film layer (PET film) with a thickness of 3-23 μm, and on its surface, through a sputtering process, in an alternating laminated manner, sequentially sputter a metal reflection layer (the material is selected from at least one of Al, Ag, and Au) and a metal / metal oxide protective layer (the material is selected from one or more of Ti, Nb, TiO 2 , NbO) to form an IR reflection layer; control the number of layers of the IR reflection layer to be 3-7 layers, and the thickness is in the range of 15-250 nm.

[0049] Prepare an IR selective emission layer: Uniformly disperse radiative cooling functional nano-ceramic particles (selected from at least one of TiO 2 , Al 2 O 3 , SiO 2 , Si 3 N 4 , BaSO 4 , SiOxNy) in a polymer resin, and then coat it on the side of the IR reflection layer that faces away from the second base film layer to form an IR selective emission layer with a thickness of 1-50 μm; ensure that the ceramic particles are firmly bonded in the polymer resin layer through chemical bonding, physical bonding, or a combination of chemical bonding and physical bonding, and the average particle spacing is controlled to be 0.5-1.5 times the average particle diameter of the ceramic particles. Each ceramic particle can be solid or hollow, with an average emissivity between 0.5 and 1 and a particle diameter less than 100 nm.

[0050] Bond the third base film layer: Bond a third base film layer (TPU film) with a thickness of 50-100 μm to the side of the IR selective emission layer that faces away from the IR reflection layer, ensuring smooth bonding and no misalignment.

[0051] Coating a self-cleaning and self-healing coating: On the side of the third substrate film layer facing away from the IR selective emission layer, a self-cleaning and self-healing functional coating with a thickness of 1-10 μm is coated to uniformly cover the surface of the third substrate film layer.

[0052] Film performance testing: Visible light transmittance testing: The transmittance of the prepared film in the visible light band is tested using a spectrophotometer. The test results show that the visible light transmittance of the film is greater than 70%, meeting the requirement of high transmittance and ensuring clear vision indoors or in the car.

[0053] Near-infrared light reflectance testing: The near-infrared light reflectance of the film is tested using an infrared spectrometer. The results show that the near-infrared light reflectance of the film is greater than 68%, effectively reflecting near-infrared light and reducing heat absorption.

[0054] Emissivity testing in the 8-13um atmospheric window: The emissivity of the film in the 8-13um atmospheric window is tested using a thermal radiation tester. The test results show that the emissivity is greater than 97%, enabling efficient heat radiation and achieving passive cooling.

[0055] Radiative cooling power testing: Under simulated actual use conditions, the radiative cooling power of the film is tested using a power testing device. The results show that the radiative cooling power is greater than 140 W / m², indicating that the film has good cooling performance.

[0056] In the specific embodiments of the present disclosure, the detailed descriptions of known functions and known components are omitted. To ensure the compatibility of the device, the operating means adopted are consistent with the parameters of market instruments.

[0057] Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art and related fields without creative efforts shall fall within the scope of protection of the present invention. The structures, devices, and operation methods not specifically described and explained in the present invention shall be implemented according to the conventional means in the art without special instructions and limitations.

Claims

1. A passive cooling radiation cooling light-transmitting film, characterized in that: It consists of the following layers stacked in sequence: The first release protective film layer has a thickness of 20-100 μm and is made of PET; The back adhesive layer has a thickness of 3-25 μm and is made of a pressure-sensitive adhesive; The first substrate film layer has a thickness of 50-100 μm and is made of TPU; The second substrate film layer has a thickness of 3-23 μm and is made of PET; An IR reflective layer having a thickness of 15-250 nm, wherein the IR reflective layer comprises a metal reflective layer and a metal / metal oxide protective layer which are alternately stacked in sequence, and the number of layers of the metal / metal oxide protective layer of the IR reflective layer is one more than the number of layers of the metal reflective layer; The IR selective emission layer has a thickness of 1-50 μm, and the IR selective emission layer material is a polymer resin layer with radiation cooling functional nano-scale ceramic particles uniformly dispersed inside; The third substrate film layer has a thickness of 50-100 μm and is made of TPU; Self-cleaning and self-repairing functional coating, the thickness of which is 1-10 μm; The second release protective film layer has a thickness of 20-100 μm, and the material of the second release protective film layer is PET.

2. The passive cooling radiation cooling light-transmitting film according to claim 1, characterized in that: The material of the metal reflective layer in the IR reflective layer is selected from at least one of Al, Ag and Au.

3. The passive cooling radiation cooling light-transmitting film according to claim 1, characterized in that: The material of the metal / metal oxide protective layer is selected from one or more of Ti, Nb, TiO2, and NbO.

4. The passive cooling radiation cooling light-transmitting film according to claim 1, characterized in that: The radiation cooling functional nano-scale ceramic particles are selected from at least one of TiO2, Al2O3, SiO2, Si3N4, BaSO4, and SiOxNy.

5. The passive cooling radiation cooling light-transmitting film according to claim 4, characterized in that: The x in the SiOxNy is between 0.1 and 2, and the y in the SiOxNy is between 0.1 and 2.

6. The passive cooling radiation cooling light-transmitting film according to claim 1, characterized in that: The ceramic particles are bonded to the ceramic IR selective emission layer by chemical bonding, physical bonding, or a combination of chemical bonding and physical bonding.

7. The passive cooling radiation cooling light-transmitting film according to claim 1, characterized in that: The average ceramic particle spacing is 0.5-1.5 times the average particle size of the ceramic particles. Each ceramic particle is solid or hollow, has an average emissivity between 0.5 and 1, and a particle size of less than 100 nm.

8. A method for preparing a passive cooling radiation cooling light-transmitting film according to any one of claims 1 to 7, characterized in that: The steps include: Step 1: After coating a pressure-sensitive adhesive on one side of the first substrate film layer, compounding the first release protective film layer with the first base film layer; Step 2: Laminating the first substrate film layer on a side of the first substrate film layer away from the first release protective film layer; Step 3: sputtering metal / metal oxide to form an IR reflective layer on a side of the second substrate film layer facing away from the first substrate film layer; Step 4: coating a polymer resin containing nano-scale ceramic particles having radiation cooling functionality on a side of the IR reflective layer away from the second substrate film layer to form an IR selective emission layer; Step 5: Laminating a third substrate film layer on a side of the IR selective emission layer facing away from the IR reflection layer; Step 6: coating a self-cleaning and self-repairing coating on a side of the third substrate film layer away from the IR selective emission layer; Step 7: Laminating a second release protective film layer on the side of the self-cleaning and self-repairing coating layer away from the third substrate film layer.

Images