Composite material and temperature-controlled tent

Abstract

The composite material provided by the application comprises a metal oxide / polyurethane film substrate, and a grid arranged in an array is arranged on one side surface of the film substrate, and the grid comprises a main body structure and a groove surrounding the main body structure. By adding metal oxide in the polyurethane, the reflectivity of the polyurethane film can be effectively improved, and when the polyurethane film is used as a tent cloth, the tent cloth has good cooling effect. By adding the paraffin phase change module in the grid of the composite material, the temperature control is realized by using the phase change characteristics of the paraffin. Further, the hollow cuboid structure is designed on the surface of the paraffin phase change module, the paraffin phase change module is fixed in the grid by interference fit with the groove of the grid structure, the preparation difficulty of the composite material is greatly reduced, the amount of the phase change material is reduced, and the stability and reliability of the composite material are improved.

Description

Technical Field

[0001] This invention relates to the field of materials technology, and in particular to a composite material and a temperature-controlled tent. Background Technology

[0002] Passive cooling is a technology that achieves cooling without energy input, relying on the structural characteristics of the material itself. Its zero-energy consumption has made it a research hotspot. Traditional radiative cooling materials mainly achieve heat radiation into space through high solar reflectivity (high reflectivity) and high infrared emissivity in the atmospheric window band (approximately 8 μm~13 μm). For example, Chinese patent application CN202110234567.X discloses a tent cooling solution based on an Al2O3 / polyethylene composite film. This solution improves the mechanical strength of the film by adding Al2O3 particles to the polyethylene matrix and composites it with an aluminum foil reflective layer to achieve 80% solar reflectivity. However, the cooling effect of this composite film is poor; when used in tent fabric, it cannot effectively maintain a low temperature inside the tent under outdoor sunlight. Summary of the Invention

[0003] In view of this, the technical problem to be solved by the present invention is to provide a composite material and a temperature-controlled tent made therefrom. When the composite material provided by the present application is used in the tent tarpaulin, it can effectively reduce the temperature inside the tent under outdoor sunlight, and has a good cooling effect.

[0004] This application provides a composite material comprising: a metal oxide / polyurethane film matrix, wherein a grid arranged in an array is provided on one side surface of the film matrix, the grid comprising a main structure and grooves surrounding the main structure.

[0005] In some specific implementations, the cross-section of the mesh is square, and the side length of the square is 20 μm to 70 μm;

[0006] The width of the trench is 1 μm to 10 μm and the depth is 20 μm to 70 μm;

[0007] The distance between adjacent outer walls of adjacent grids is 10 μm to 50 μm.

[0008] In some specific implementations, a highly thermally conductive coating is formed within the trench.

[0009] In some specific implementations, a paraffin phase change module is provided within the grid; the paraffin phase change module is connected to the grid through a high thermal conductivity layer.

[0010] In some specific implementations, the paraffin phase change module includes a cuboid and a hollow cuboid connected to the cuboid;

[0011] The cross-sections of the cuboid, the hollow cuboid, and the grid overlap;

[0012] The hollow cuboid and the groove form an interference fit, fixing the paraffin phase change module in the grid.

[0013] In some specific implementations, the height of the cuboid is 10 μm to 100 μm;

[0014] The height of the hollow cuboid is 1 μm to 10 μm.

[0015] In some specific implementations, the metal oxide in the metal oxide / polyurethane film matrix is ​​TiO2.

[0016] In some specific implementations, the metal oxide / polyurethane film substrate includes a fabric and a metal oxide / polyurethane layer laminated on the surface of the fabric.

[0017] In some specific implementations, the metal oxide accounts for 1% to 20% of the weight of the polyurethane;

[0018] The particle size of the metal oxide is 100 nm to 800 nm.

[0019] This application also provides a temperature-controlled tent, comprising the composite material described in the above technical solution.

[0020] This application provides a composite material comprising: a metal oxide / polyurethane film matrix, wherein an array of grids is arranged on one side surface of the film matrix, the grids comprising a main structure and grooves surrounding the main structure. This application adds metal oxides to the polyurethane and simultaneously forms an array of grids on the film surface, effectively improving the reflectivity of the polyurethane film and providing excellent cooling when used as tent fabric. Furthermore, this application incorporates a paraffin phase change module within the grid of the composite material, utilizing the phase change properties of paraffin to achieve temperature control. Specifically, when the external temperature rises, the paraffin absorbs heat and undergoes a phase change to maintain a low temperature inside the tent; when the external temperature decreases, the paraffin undergoes a phase change and releases heat, thereby increasing the temperature inside the tent, thus achieving intelligent temperature control of the tent. Even further, this application designs a hollow cuboid structure on the surface of the paraffin phase change module, which, through an interference fit with the grooves of the grid structure, fixes the paraffin phase change module within the grid, significantly reducing the difficulty of composite material preparation, reducing the amount of phase change material used, and improving the stability and reliability of the composite material. Attached Figure Description

[0021] Figure 1 This is a top view of the grid array structure formed in this application;

[0022] Figure 2 A top view of the standardized paraffin phase change module provided in this application;

[0023] Figure 3 This is a schematic diagram of the structure of the cubic tent frame provided in the embodiments of this application;

[0024] Figure 4 A photograph of the tent prepared according to Embodiment 1 of this application;

[0025] Figure 5 This is a statistical graph showing the fracture strength of the materials prepared in the embodiments and comparative examples of this application;

[0026] Figure 6 This is a statistical chart of the elongation at break of the materials prepared in the embodiments and comparative examples of this application. Detailed Implementation

[0027] This invention provides a composite material and a temperature-controlled tent. Those skilled in the art can refer to the content of this document and appropriately modify the process parameters to achieve the desired result. The methods and applications of this invention have been described through preferred embodiments. It is evident that those skilled in the art can modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit, and scope of this invention to realize and apply the technology of this invention.

[0028] The terms “including,” “having,” or “containing,” including the use of their grammatical synonyms, should generally be understood as open-ended and non-restrictive, for example, not excluding other unstated elements or steps, unless otherwise specifically stated or understood from the context.

[0029] It should be understood that the order of the steps or the order in which certain actions are performed is not important as long as the invention remains operational. Furthermore, two or more steps or actions can be performed simultaneously.

[0030] The use of any and all instances or exemplary language such as “e.g.” or “including” in this document is merely intended to better illustrate the invention and is not intended to limit the scope of the invention unless the claims are made. No language in this specification should be construed as indicating that any unclaimed element is essential to the practice of the invention.

[0031] Furthermore, the numerical ranges and parameters used to define the present invention are approximate values, and the relevant values ​​in the specific embodiments have been presented as precisely as possible. However, any value inevitably contains standard deviations due to individual test methods. Therefore, unless explicitly stated otherwise, it should be understood that all ranges, quantities, values, and percentages used in this disclosure are modified with the word "approximately". Here, "approximately" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a specific value or range.

[0032] This application provides a composite material comprising: a metal oxide / polyurethane film matrix, wherein a grid arranged in an array is provided on one side surface of the film matrix, the grid comprising a main structure and grooves surrounding the main structure.

[0033] The composite material provided in this application includes a metal oxide / polyurethane film matrix, i.e., a polyurethane film with added metal oxide. In some specific implementations, the thickness of the metal oxide / polyurethane film matrix is ​​10 μm to 500 μm, preferably 50 μm to 400 μm. In some specific implementations, the metal oxide is nanoparticles, with a particle size preferably 100 nm to 800 nm, more preferably 200 nm to 600 nm. In some specific implementations, the metal oxide accounts for 1% to 20% of the weight of the polyurethane, preferably 5% to 20%, more preferably 10% to 20%. In some specific implementations, the metal oxide is TiO2. In some specific implementations, the metal oxide / polyurethane film matrix includes a fabric and a metal oxide / polyurethane layer laminated on the surface of the fabric. Using a fabric and a metal oxide / polyurethane layer composite can further reduce the emissivity of the composite material. This application does not have any special limitations on the fabric, and it can be nylon fabric, etc. Specifically, the thickness of the fabric is 5 μm to 400 μm, preferably 50 μm to 300 μm; the thickness of the metal oxide / polyurethane layer is 5 μm to 400 μm, preferably 10 μm to 300 μm.

[0034] This application does not impose any special restrictions on the preparation method of the film substrate. It can be prepared using a casting method, for example, by melt-blending polyurethane resin and metal oxide, followed by extrusion casting to obtain a metal oxide / polyurethane film substrate. When the metal oxide / polyurethane film substrate includes a fabric and a metal oxide / polyurethane layer composited on the surface of the fabric, it can be prepared using the following method: melt-blending polyurethane resin and metal oxide, extruding, and directly coating onto the surface of the fabric, followed by setting to obtain a metal oxide / polyurethane film substrate including the fabric and a metal oxide / polyurethane layer composited on the surface of the fabric. This application does not impose any special restrictions on the processes and parameters of the melt extrusion, casting, coating, and setting operations; processes and parameters commonly used by those skilled in the art are acceptable.

[0035] In the composite material provided in this application, one surface of the film matrix is ​​provided with an array of grids, the grids including a main structure and grooves surrounding the main structure. See also Figure 1 , Figure 1This is a top view of the grid array structure formed in this application, where 1 is the grid, 11 is the main structure, and 12 is the groove 12 surrounding the main structure 11.

[0036] The grid 1 is arranged in an array on the surface of the thin film substrate. Those skilled in the art will understand that an array arrangement refers to multiple geometric structures comprising multiple rows and columns, which can be a row-column arrangement or a honeycomb arrangement; this application does not have any particular limitation in this regard. In this application, the grid 1 includes a main structure 11 and grooves 12 surrounding the main structure. The grooves 12 separate the main structure 11 from other areas of the thin film substrate where the grid 1 is not located. In some specific implementations, the cross-section of the grid 1 is square, and the side length a of the square is preferably 20 μm to 70 μm, more preferably 30 μm to 60 μm, and most preferably 40 μm to 50 μm. In some specific implementations, the width b of the groove 12 is 1 μm to 10 μm, preferably 3 μm to 8 μm, more preferably 4 μm to 7 μm; the depth of the groove 12 is 20 μm to 70 μm, preferably 30 μm to 60 μm, and more preferably 40 μm to 50 μm. In some specific implementations, the distance c between adjacent outer walls of adjacent grids is 10 μm to 50 μm, preferably 15 μm to 45 μm, and more preferably 20 μm to 40 μm. The arrayed grids on the surface of the thin film substrate can increase the reflectivity of the thin film by 5% to 10%, thereby improving the cooling effect.

[0037] This application does not impose any particular restrictions on the formation method of the mesh, but preferably employs a hot-pressing process to form the corresponding mesh structure on the surface of the film substrate. Specifically, this application uses a mold with a raised structure that matches the mesh structure (details will not be elaborated here), places one side surface of the composite film in contact with the mold, performs hot pressing, and cools and sets the composite film temperature using an air-cooling system before releasing the pressure, thus forming a mesh array on the surface of the composite film. In some specific implementations, the hot-pressing temperature is 100℃~200℃, preferably 120℃~180℃; the pressure is 0.5 MPa~5 MPa, preferably 1 MPa~3 MPa; and the time is 50 s~200 s, preferably 80 s~150 s.

[0038] In some specific implementations, a high thermal conductivity coating is formed within the trench, which enables heat transfer in the composite material. This application does not impose any particular limitations on the high thermal conductivity coating, but it is preferably formed from a high thermal conductivity resin with a thermal conductivity ≥3.5 W / m·K. The high thermal conductivity resin is preferably a silicone resin, such as a single-component organosilicon material of type HN-3245. This application does not impose any particular limitations on the formation method of the high thermal conductivity coating; the high thermal conductivity resin coating is applied into the trench and cured to obtain the high thermal conductivity coating.

[0039] In some specific implementations, a paraffin phase change module is disposed within the grid. The paraffin phase change module is connected to the grid via a high thermal conductivity layer to achieve heat transfer. Specifically, the thermal resistance of the graphite phase change module and the composite material is <0.002 m. 2 • K / W, significantly improving heat transfer efficiency. In some specific implementations, the paraffin phase change module includes paraffin wax and packaging material encapsulating the paraffin wax. In some specific implementations, the packaging material can be aluminum-plastic composite material. This application does not impose any special restrictions on the preparation method of the paraffin phase change module; it can be prepared according to the following method: molding the paraffin wax and then encapsulating it with the packaging material. In some specific implementations, the molding method of the paraffin wax can be extrusion calendering. In some specific implementations, the encapsulation method can be encapsulation using a high-speed heat sealing machine. This application does not impose any special restrictions on the molding and encapsulation processes and parameters; processes and parameters commonly used by those skilled in the art are acceptable.

[0040] In some specific implementations, the paraffin phase change module includes a cuboid and a hollow cuboid connected to the cuboid;

[0041] The cross-sections of the cuboid, the hollow cuboid, and the grid overlap;

[0042] The hollow cuboid and the groove form an interference fit, fixing the paraffin phase change module in the grid.

[0043] See Figure 2 , Figure 2This is a top view of the standardized paraffin phase change module provided in this application. The standardized paraffin phase change module includes a cuboid 21 and a hollow cuboid 22 connected to the cuboid. The cross-sections of the cuboid 21, the hollow cuboid 22, and the grid 1 completely overlap, causing the wall of the hollow cuboid to form an interference fit with the grooves of the grid, thus fixing the paraffin phase change module within the grid. In some specific implementations, the tolerance of the interference fit is -0.1 μm to +0.05 μm. The cross-sections of the cuboid 21 and the hollow cuboid 22 are the same as and overlap with the cross-section of the grid. In some specific implementations, the cross-section of the cuboid 21 is a square, preferably with a side length of 20 μm to 70 μm, more preferably 30 μm to 60 μm, and most preferably 40 μm to 50 μm. The height of the cuboid 21 is preferably 20 μm to 70 μm, more preferably 30 μm to 60 μm, and most preferably 40 μm to 50 μm. In some specific implementations, the cross-section of the hollow cuboid 22 is a square, and the side length of the square is preferably 20 μm to 70 μm, more preferably 30 μm to 60 μm, and most preferably 40 μm to 50 μm. In some specific implementations, the height of the hollow cuboid 22 is preferably 1 μm to 10 μm, preferably 3 μm to 8 μm, and more preferably 4 μm to 7 μm. In some specific implementations, the wall thickness a2 of the hollow cuboid 22 is adapted to the width of the groove and forms an interference fit, preferably 1 μm to 10 μm, preferably 3 μm to 8 μm, and more preferably 4 μm to 7 μm.

[0044] In some specific implementations, the areal density of the paraffin phase change module is 25 g / m³. 2 ~45 g / m 2 It can achieve differentiated thermal management by changing the areal density of the paraffin phase change module.

[0045] This application precisely embeds the paraffin phase change module into the grid on the surface of the thin film substrate through an interference fit. The high thermal conductivity coating on the groove surface achieves zero-gap thermal contact between the paraffin phase change module and the thin film substrate, eliminating the need for additional fixing materials and greatly reducing installation costs.

[0046] This application also provides a temperature-controlled tent, comprising the composite material described in the above technical solution. The composite material described in the above technical solution can be used as a tent fabric, with the mesh side facing outwards. It achieves efficient cooling through the optical microstructure (i.e., mesh) on the thin film surface, while simultaneously absorbing and releasing heat through an embedded paraffin phase change module, thus maintaining temperature stability.

[0047] This application provides a composite material comprising: a metal oxide / polyurethane film matrix, wherein one side surface of the film matrix is ​​provided with an array of grids, the grids comprising a main structure and grooves surrounding the main structure. This application adds metal oxide to the polyurethane and simultaneously forms an array of grids on the film surface, effectively improving the reflectivity of the polyurethane film and providing excellent cooling when used as tent fabric. Furthermore, this application incorporates a paraffin phase change module within the grid of the composite material, utilizing the phase change properties of paraffin to achieve temperature control. For example, when the external temperature is high, paraffin absorbs external heat to maintain a low temperature inside the tent; when the external temperature decreases, paraffin releases heat through phase change, increasing the temperature inside the tent, thereby achieving intelligent temperature control of the tent. Even further, this application designs a hollow cuboid structure on the surface of the paraffin phase change module, which, through an interference fit with the grooves of the grid structure, fixes the paraffin phase change module within the grid, significantly reducing the difficulty of composite material preparation, reducing the amount of phase change material used, and improving the stability and reliability of the composite material.

[0048] The present application will be further described below with reference to the embodiments.

[0049] Example 1

[0050] 100 parts by weight of dried thermoplastic polyurethane elastomer (TPU) granules (model A990) were mixed evenly with 10 parts by weight of TiO2 powder with a particle size of 400 nm. The mixture was then added to the barrel of a casting machine. The barrel temperature was set to 180 ℃~190 ℃, the die temperature to 185 ℃, and the screw speed to 60 r / min. The materials were then completely melted and mixed evenly to obtain a TPU-TiO2 melt system.

[0051] Using a nylon fabric with a thickness of 200 μm as a substrate, a composite film was prepared by an integrated casting composite process: the nylon fabric was first flattened and fixed by a tension roller, and the above-mentioned TPU-TiO2 molten system was simultaneously extruded through a casting die and directly coated onto the surface of the nylon fabric. After being shaped by a cooling roller and traction-wound, a continuous composite film with a width of 1.5 m was obtained, and the thickness of the composite film was 300 μm ± 10 μm.

[0052] A mold is provided with an array of protrusions on its surface. Each protrusion is a hollow cube with a height of 50 μm, a wall thickness of 5 μm, and an outer wall side length of 50 μm. The distance between the outer walls of adjacent surfaces of two adjacent hollow cubes is 20 μm. One surface of the composite film is brought into contact with the mold, and contact hot pressing is performed at a temperature of 160 ℃ ± 5 ℃ and a pressure of 1.2 MPa ± 0.2 MPa, maintaining the pressure for 120 s ± 10 s. Before releasing the pressure, the composite film temperature is reduced to below 80 ℃ using an air-cooling system for shaping. A square grid array is formed on the surface of the composite film. See [link to documentation]. Figure 1 , Figure 1 This is a top view of the grid array structure formed in this application. 1 is a grid, and the cross-section of grid 1 is a square with a side length a of 50 μm. Grid 1 includes a main structure 11 and a groove 12 surrounding the main structure. The width b of the groove 12 is 5 μm and the depth is 50 μm. The distance c between the outer walls of adjacent grooves of adjacent grids is 20 μm.

[0053] Example 2

[0054] A standardized paraffin phase change module was obtained by encapsulating paraffin wax in aluminum-plastic composite material. (See [link to relevant documentation]). Figure 2 , Figure 2 This is a top view of the standardized paraffin phase change module provided in this application. The standardized paraffin phase change module includes a cuboid 21 with a square cross-section and a hollow cuboid 22 connected to the cuboid. The square cross-sections of the cuboid 21 and the hollow cuboid 22 completely overlap. The height of the cuboid is 45 μm, and the side length of its square cross-section is 50 μm ± 5 μm. The height of the hollow cuboid is 5 μm, the outer wall side length a1 of its square cross-section is 50 μm ± 5 μm, and the wall thickness a2 of the hollow cuboid is 5 μm.

[0055] A high thermal conductivity resin (a single-component organosilicon material of model HN-3245) with a thermal conductivity ≥3.5 W / m·K was coated in the grooves 11 on the surface of the composite film prepared in Example 1. After curing, a resin layer with a thickness of 5 μm was formed. The above-mentioned standardized paraffin phase change module was embedded and installed on the surface of the composite film, so that the hollow cuboid of the standardized paraffin phase change module and the groove of the film grid formed an interference fit. Then, contact hot pressing was performed under the conditions of 160 ℃±5 ℃ and 1.2 MPa±0.2 MPa, and the pressurization time was maintained for 120 s±10 s. Before the pressure was released, the temperature of the composite film was reduced to below 80 ℃ by the air cooling system to fix the shape, so that the standardized paraffin phase change module was embedded and installed on the surface of the composite film to form a composite material.

[0056] Example 3

[0057] 100 parts by weight of dried thermoplastic polyurethane elastomer (TPU) granules (model A990) were mixed evenly with 10 parts by weight of TiO2 powder with a particle size of 100 nm. The mixture was then added to the barrel of a casting machine. The barrel temperature was set to 180 ℃~190 ℃, the die temperature to 185 ℃, and the screw speed to 60 r / min to ensure that the material was completely melted and mixed evenly. The mixture was then extruded through a wide die onto the surface of a cooling roller. After traction and winding, a TPU-TiO2 film with a width of 1.5 m and a thickness of 70 μm±10 μm was prepared.

[0058] A mold is provided with an array of protrusions on its surface. Each protrusion is a hollow cube with a height of 50 μm, a wall thickness of 5 μm, and an outer wall side length of 50 μm. The distance between the outer walls of adjacent surfaces of two adjacent hollow cubes is 20 μm. One surface of the TPU-TiO2 film is brought into contact with the mold, and contact hot pressing is performed at a temperature of 160 ℃ ± 5 ℃ and a pressure of 1.2 MPa ± 0.2 MPa, maintaining the pressure for 120 s ± 10 s. Before releasing the pressure, the TPU-TiO2 film temperature is reduced to below 80 ℃ using an air-cooling system for shaping. A square grid array is formed on the surface of the TPU-TiO2 film. See [link to documentation]. Figure 1 , Figure 1 This is a top view of the grid array structure formed in this application. 1 is a grid, and the cross-section of grid 1 is a square with a side length a of 50 μm. Grid 1 includes a main structure 11 and a groove 12 surrounding the main structure. The width b of the groove 12 is 5 μm and the depth is 50 μm. The distance c between the outer walls of adjacent grooves of adjacent grids is 20 μm.

[0059] Example 4

[0060] A standardized paraffin phase change module was obtained by encapsulating paraffin wax in aluminum-plastic composite material. (See [link to relevant documentation]). Figure 2 , Figure 2 This is a top view of the standardized paraffin phase change module provided in this application. The standardized paraffin phase change module includes a cuboid 21 with a square cross-section and a hollow cuboid 22 connected to the cuboid. The square cross-sections of the cuboid 21 and the hollow cuboid 22 completely overlap. The height of the cuboid is 45 μm, and the side length of its square cross-section is 50 μm ± 5 μm. The height of the hollow cuboid is 5 μm, the outer wall side length a1 of its square cross-section is 50 μm ± 5 μm, and the wall thickness a2 of the hollow cuboid is 5 μm.

[0061] A high thermal conductivity resin (a single-component organosilicon material of model HN-3245) with a thermal conductivity ≥3.5 W / m·K was coated in the grooves 11 on the surface of the TPU-TiO2 film prepared in Example 3. After curing, a resin layer with a thickness of 5 μm was formed. The above-mentioned standardized paraffin phase change module was embedded and installed on the surface of the TPU-TiO2 film, so that the hollow cuboid of the standardized paraffin phase change module and the groove of the film grid form an interference fit. Then, contact hot pressing was performed under the conditions of temperature 160±5 ℃ and pressure 1.2±0.2 MPa, and the pressurization time was maintained for 120 s±10 s. Before the pressure was released, the temperature of the TPU-TiO2 film was reduced to below 80 ℃ by the air cooling system to fix the shape, so that the standardized paraffin phase change module was embedded and installed on the surface of the TPU-TiO2 film to form a composite material.

[0062] Comparative Example 1

[0063] 100 parts by weight of dried thermoplastic polyurethane elastomer (TPU) granules (model A990) were added to the barrel of a casting machine. The barrel temperature was set to 180 ℃~190 ℃, the die temperature to 185 ℃, and the screw speed to 60 r / min to ensure that the material was completely melted and mixed evenly. Then, the material was extruded and cast onto the surface of the cooling roller through a wide die. After traction and winding, a transparent TPU film with a width of 1.5 m and a thickness of 70 μm±10 μm was prepared.

[0064] A mold is provided with an array of protrusions on its surface. Each protrusion is a hollow cube with a height of 50 μm, a wall thickness of 5 μm, and an outer wall side length of 50 μm. The distance between the outer walls of adjacent surfaces of two adjacent hollow cubes is 20 μm. One surface of a TPU film is brought into contact with the mold, and contact hot pressing is performed at a temperature of 160 ℃ ± 5 ℃ and a pressure of 1.2 MPa ± 0.2 MPa, maintaining the pressure for 120 s ± 10 s. Before releasing the pressure, the TPU film temperature is reduced to below 80 ℃ using an air-cooling system for shaping. A square grid array is formed on the surface of the TPU film. See [link to documentation]. Figure 1 , Figure 1 This is a top view of the grid array structure formed in this application. 1 is a grid, and the cross-section of grid 1 is a square with a side length a of 50 μm. Grid 1 includes a main structure 11 and a groove 12 surrounding the main structure. The width b of the groove 12 is 5 μm and the depth is 50 μm. The distance c between the outer walls of adjacent grooves of adjacent grids is 20 μm.

[0065] Comparative Example 2

[0066] A standardized paraffin phase change module was obtained by encapsulating paraffin wax in aluminum-plastic composite material. (See [link to relevant documentation]). Figure 2 , Figure 2 This is a top view of the standardized paraffin phase change module provided in this application. The standardized paraffin phase change module includes a cuboid 21 with a square cross-section and a hollow cuboid 22 connected to the cuboid. The square cross-sections of the cuboid 21 and the hollow cuboid 22 completely overlap. The height of the cuboid is 45 μm, and the side length of its square cross-section is 50 μm ± 5 μm. The height of the hollow cuboid is 5 μm, the outer wall side length a1 of its square cross-section is 50 μm ± 5 μm, and the wall thickness a2 of the hollow cuboid is 5 μm.

[0067] A high thermal conductivity resin (a single-component silicone material of model HN-3245) with a thermal conductivity ≥3.5 W / m·K was coated in the grooves 11 on the surface of the transparent TPU film prepared in Comparative Example 1. After curing, a resin layer with a thickness of 5 μm was formed. The above-mentioned standardized paraffin phase change module was embedded and installed on the surface of the transparent TPU film, so that the hollow cuboid of the standardized paraffin phase change module and the groove of the film grid formed an interference fit. Then, contact hot pressing was performed under the conditions of temperature 160±5 ℃ and pressure 1.2±0.2 MPa, and the pressure was maintained for 120 s±10 s. Before the pressure was released, the temperature of the transparent TPU film was reduced to below 80 ℃ by the air cooling system to fix the shape, so that the standardized paraffin phase change module was embedded and installed on the surface of the transparent TPU film to form a composite material.

[0068] Application Example 1

[0069] Provide such as Figure 3 The cube-shaped tent frame shown is Figure 3 This is a schematic diagram of the cubic tent frame provided in the embodiments of this application, with dimensions of 1 m * 1 m * 1 m. The films prepared in Examples 1-4 and Comparative Examples 1-2 are precisely cut to the designed dimensions and firmly fixed to the tent frame using methods such as glue, tape, or sewing, with the side imprinted with the grid array structure facing outwards. This ensures a seamless bonding between the film and the frame, free of bubbles and wrinkles, resulting in the tent, as shown in the physical image. Figure 4 As shown, Figure 4 A photograph of the tent prepared according to Embodiment 1 of this application.

[0070] The tents prepared above were placed on open ground that could be exposed to sunlight for all-weather temperature control experiments. Thermocouples were used to monitor the internal temperature of the tents in real time, and solar power meters were used to monitor the solar irradiance in real time. A 24-hour continuous outdoor experiment was carried out at 22 ℃ to 35 ℃. During the experiment, the internal temperature of the tents and the real-time solar power were recorded simultaneously.

[0071] The reflectance, average temperature and maximum temperature of each tent were calculated. The results are shown in Tables 1 and 2. Table 2 shows the reflectance results of the tents provided in the embodiments and comparative examples of this application, and Table 2 shows the average temperature and maximum temperature of the tents provided in the embodiments and comparative examples of this application.

[0072] Table 1. Reflectance results of the tents provided in the embodiments and comparative examples of this application.

[0073]

[0074] As shown in Table 1, the addition of TiO2 significantly improves the reflectivity of the polyurethane film. Comparative Example 1 is a transparent polyurethane film without TiO2, with a reflectivity of only 10.15%; Example 3 is a polyurethane film with only TiO2 added, and the reflectivity is increased to 65.50%, which is significantly higher than that of Comparative Example 1. This indicates that TiO2 can effectively enhance the reflectivity of the film.

[0075] The solar spectral reflectance of different samples varied significantly, which is closely related to the material composition and structure. The average reflectance of the pure TPU film prepared in Comparative Example 1 was only 10.15%, indicating that the pure TPU matrix cannot effectively block sunlight and lacks passive cooling performance. The average reflectance of the TPU-TiO2 film prepared in Example 3 reached 65.50%, thanks to the high reflectivity of rutile TiO2. After being uniformly dispersed in the TPU matrix, it can effectively reflect visible and near-infrared energy from sunlight, increasing reflectivity and giving the material passive cooling potential. The TPU-TiO2 fabric composite film prepared in Example 1 further improved its reflectivity, reaching an average reflectance of 76.74%. This is because the fabric, as a substrate, combined with the TPU-TiO2 coating, not only increased the overall thickness of the composite film but also increased the number of solar reflections through the multi-level pores of the fabric fibers, further enhancing the reflectivity.

[0076] Table 2. Results of the average and maximum temperatures throughout the day for the tents provided in the embodiments of this application and Comparative Example 1.

[0077]

[0078] As shown in Table 2:

[0079] The polyurethane films with added TiO2 (Example 1 and Comparative Example 3) showed a significant cooling effect compared to the transparent film without added TiO2 (Comparative Example 1), with an average temperature reduction of 2.2 ℃ to 5.4 ℃ throughout the day, a maximum temperature reduction of 2.3 ℃ to 5.9 ℃, and an instantaneous temperature difference of ≥2 ℃ at each time point. In Example 1, which used a TiO2 / polyurethane composite fabric film, the average temperature throughout the day was further reduced by 3.2 ℃, the maximum temperature was reduced by 3.6 ℃, and the instantaneous temperature difference reached ≥5 ℃ compared to the ordinary TiO2 film (Example 3).

[0080] Of particular note is that the system integrating the paraffin phase change refrigeration module (Example 2, Example 3, and Comparative Example 2) exhibits superior temperature control performance: compared to the corresponding group without the module, Example 2 is 3.1 ℃ (average) / 1.3 ℃ (maximum) lower than Example 1, Example 4 is 3.9 ℃ / 3.3 ℃ lower than Example 3, and Comparative Example 2 is 2.7 ℃ / 1.8 ℃ lower than Comparative Example 1, fully verifying the technical advantages of the "optical reflection-phase change energy storage" synergistic temperature control system.

[0081] Therefore, it is feasible to fabricate a smart temperature-controlled tent using a TiO2 / polyurethane composite film in synergy with a modular phase-change refrigeration unit. Its "reflection-energy storage" dual-mode synergistic design effectively improves reflectivity, thereby enhancing temperature control. This smart temperature-controlled tent is suitable for thermal management in outdoor activities and field operations. By optimizing material ratios and structural design, its temperature control performance can be further improved, reducing reliance on active cooling equipment and achieving energy conservation and sustainable development.

[0082] Experimental Example 2

[0083] 2.1 Mechanical properties

[0084] To evaluate the reliability of the materials in engineering scenarios such as outdoor tents and temporary buildings, mechanical property tests were conducted on the materials prepared in Example 1 (TPU-TiO2 / PA), Example 3 (TPU-TiO2), and Comparative Example 1 (TPU), as well as on commercial tarpaulins. The results are as follows: Figure 5 and Figure 6 As shown, Figure 5 This is a statistical graph showing the fracture strength of the materials prepared in the embodiments and comparative examples of this application. Figure 6 This is a statistical chart of the elongation at break of the materials prepared in the embodiments and comparative examples of this application.

[0085] Depend on Figure 5 and Figure 6 It can be known that:

[0086] Regarding tensile strength, the pure TPU film prepared in Comparative Example 1 exhibited a tensile strength of 24.9 MPa, while the TPU-TiO2 film prepared in Example 3 showed a tensile strength increased to 43.44 MPa. This is because the 10% added TiO2, acting as an inorganic rigid filler, forms a stable interface with the TPU matrix after uniform dispersion. Under stress, it effectively transfers load through interfacial interaction, and its high rigidity inhibits TPU molecular chain slippage, hinders crack initiation and propagation, thereby improving tensile strength. The TPU-TiO2 / PA composite film prepared in Example 1 further increased its tensile strength to 72.47 MPa, a 191.04% improvement over pure PU. This is because nylon fabric itself possesses excellent tensile strength. As a substrate, it forms an integrated structure with the TPU-TiO2 coating, acting as a load-bearing skeleton to bear the main load, effectively dispersing local stress concentration and improving the tensile strength of the composite system. The tensile strength of the control group's commercial PVC tarpaulin was only 9.53 MPa.

[0087] In terms of elongation at break, both the pure TPU film prepared in Comparative Example 1 and the TPU-TiO2 film prepared in Example 3 exhibited excellent toughness, with elongation at break of 740% and 917%, respectively. The elongation at break of the TPU-TiO2 / PA film prepared in Example 1 was 44%, which is still higher than the 27% of commercial PVC tarpaulin, and it possesses the basic flexibility and deformation resistance required for outdoor scenarios. The core reason for the decrease in toughness of the TPU-TiO2 / PA film prepared in Example 1 lies in the rigid constraint of the nylon fabric: the nylon fabric is a rigid fiber weave structure with tightly packed molecular chains, high crystallinity, and low elongation at break. When combined with the TPU-TiO2 coating, it significantly restricts the free stretching and contraction of the TPU molecular chains in the coating. Under stress, the flexible coating needs to deform in tandem with the rigid fabric. The rigidity of the fabric fibers greatly restricts the deformation capacity of the overall system. Moreover, the strong interfacial bonding between the coating and the fabric further inhibits the slippage of the TPU molecular chains, exacerbating the reduction in toughness. However, the 44% elongation at break can still meet the requirements for slight deformation such as wind and pulling in outdoor scenarios.

[0088] In summary, the prepared TPU-TiO2 / PA composite film achieves a high reflectivity of 76.74% and efficient passive cooling performance, while also exhibiting a high tensile strength of 72.47 MPa and an elongation at break of 44%, meeting the mechanical performance requirements of outdoor experiments and further expanding the application fields of passive radiation cooling materials.

[0089] 2.2 Thermal stability

[0090] Thermogravimetric analysis was performed on the film materials and commercial tarpaulins prepared in Examples 1-4 and Comparative Examples 1-2. The results are shown in Table 3. Table 3 contains the thermogravimetric data of the film materials provided in the examples and comparative examples of this application.

[0091] Table 3. Thermogravimetric data of the thin film materials provided in the embodiments and comparative examples of this application.

[0092]

[0093] Table 3 shows that the 5% weight loss temperature of the pure TPU film prepared in Comparative Example 1 is 310.11 ℃, the 10% weight loss temperature is 323.26 ℃, and the maximum weight loss rate temperature is 471.90 ℃, reflecting the basic thermal stability of the TPU matrix. The 5% weight loss temperature of the TPU-TiO2 film prepared in Example 3 is increased to 321.06 ℃ (approximately 10 ℃ higher than pure TPU), the 10% weight loss temperature is 335.18 ℃, and the maximum weight loss rate temperature slightly increases to 475.71 ℃. This is because TiO2, as a rigid filler, inhibits the thermal motion of the TPU molecular chains, delays thermal decomposition, and improves the thermal stability of the system. The 5% weight loss temperature (310.15 ℃) of the TPU-TiO2 / PA film prepared in Example 1 is close to that of pure TPU, but the maximum weight loss rate temperature decreases to 357.10 ℃. This is because the thermal decomposition temperature of nylon (PA) fabric (approximately 350℃) is... The temperature of PA in the composite system is lower than that of the TPU matrix, which leads to rapid decomposition of PA at around 350 °C. The 5% weight loss temperature of commercial tarpaulin is only 239.81 °C, which is much lower than that of the passive radiation cooling roll material.

[0094] After the addition of the phase change paraffin module, the thermal decomposition initiation temperature of the phase change paraffin (a mixture of alkanes) is much lower than that of all TPU matrices (approximately 200 °C to 250 °C). During modular integration, even with good encapsulation, paraffin molecules remaining at the interface or in the process can become weak points in the material system under long-term high temperatures, potentially causing the 5% weight loss temperature to migrate to varying degrees towards the decomposition temperature of paraffin.

[0095] Although the addition of the paraffin module is expected to decrease the initial thermal decomposition temperature (5% weight loss) of all systems by 5-20 °C, the actual values ​​are still much higher than (>100 °C) the extreme high-temperature outdoor environment temperature (typically <80 °C). Therefore, from the perspective of material thermal decomposition, the thermal stability requirements for outdoor applications can be fully met.

[0096] In summary, the initial thermal decomposition temperatures of the prepared TPU-based samples were all above 300 ℃, which is far higher than the highest outdoor temperature, and fully meets the requirements for outdoor thermal stability.

[0097] 2.3 UV resistance test

[0098] Ultraviolet radiation in outdoor service environments can easily lead to molecular chain degradation and performance decline in passive radiation cooling materials, which is one of the core factors restricting the long-term application of passive radiation cooling materials. Therefore, the comparative and exemplary samples were subjected to continuous ultraviolet irradiation for 7 days using an ultraviolet aging chamber to test the change in reflectance before and after aging. The results are shown in Table 4, which presents the reflectance change data of the thin film materials provided in the exemplary and comparative samples of this application before and after aging.

[0099] Table 4. Data on the change in reflectance of the thin film materials provided in the embodiments and comparative examples of this application before and after aging.

[0100]

[0101] As shown in Table 4:

[0102] Before UV aging, the reflectivities of the films prepared in Comparative Example 1, Example 3, Example 1, Comparative Example 2, Example 4, and Example 2 were 10.15%, 65.50%, 76.74%, 10.10%, 64.32%, and 75.54%, respectively; after aging, the reflectivities of the corresponding films were 10.40%, 62.25%, 72.68%, 10.01%, 61.78%, and 71.52%, respectively. From the trend, the reflectivity of pure TPU film showed no significant fluctuation. The reflectivity of the TPU-TiO2 film prepared in Example 3 decreased by 3.25%, and the reflectivity of the TPU-TiO2 / PA film prepared in Example 1 decreased by 4.06%. This is because ultraviolet radiation causes slight molecular chain degradation on the material surface, resulting in a slight change in surface roughness. However, rutile TiO2 itself has excellent ultraviolet shielding and photostability, which can effectively inhibit the photodegradation of the TPU matrix. At the same time, the structural support of the nylon (PA) fabric reduces the deformation and aging of the coating. Therefore, the decrease was less than 5%, and the reflectivity of the material remained at a high level after aging, meeting the requirements of passive cooling. The introduction of the standard phase change paraffin module, due to its encapsulation material and interface effect, slightly exacerbates the ultraviolet aging of the polyurethane film system, but has a limited impact on the composite film with TiO2 as the functional core. TPU-TiO2 and TPU-TiO2 / PA-based smart temperature control materials, after module integration, remain the preferred solution for outdoor applications with high reflectivity and excellent weather resistance.

[0103] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A composite material, characterized in that, include: A metal oxide / polyurethane thin film substrate, wherein one side surface of the thin film substrate is provided with an array of grids, the grids including a main structure and grooves surrounding the main structure.

2. The composite material according to claim 1, characterized in that, The cross-section of the grid is square, and the side length of the square is 20 μm to 70 μm; The width of the trench is 1 μm to 10 μm and the depth is 20 μm to 70 μm; The distance between adjacent outer walls of adjacent grids is 10 μm to 50 μm.

3. The composite material according to claim 1 or 2, characterized in that, A highly thermally conductive coating is formed within the trench.

4. The composite material according to claim 3, characterized in that, A paraffin phase change module is provided within the grid; The paraffin phase change module is connected to the mesh through a high thermal conductivity layer.

5. The composite material according to claim 4, characterized in that, The paraffin phase change module includes a cuboid and a hollow cuboid connected to the cuboid; The cross-sections of the cuboid, the hollow cuboid, and the grid overlap; The hollow cuboid and the groove form an interference fit, fixing the paraffin phase change module in the grid.

6. The composite material according to claim 5, characterized in that, The height of the cuboid is 10 μm to 100 μm; The height of the hollow cuboid is 1 μm to 10 μm.

7. The composite material according to any one of claims 1 to 6, characterized in that, In the metal oxide / polyurethane film matrix, the metal oxide is TiO2.

8. The composite material according to claim 7, characterized in that, The metal oxide / polyurethane film substrate includes a fabric and a metal oxide / polyurethane layer laminated on the surface of the fabric.

9. The composite material according to claim 7, characterized in that, The metal oxide accounts for 1% to 20% of the weight of the polyurethane; The particle size of the metal oxide is 100 nm to 800 nm.

10. A temperature-controlled tent comprising the composite material described in any one of claims 1 to 9.

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