Infrared low emissivity material with high radio wave permeability and preparation method thereof

Abstract

The present application relates to the technical field of functional new material, and more particularly to a radio electromagnetic wave high-transmission infrared low-emissivity material and a preparation method thereof.The radio electromagnetic wave high-transmission infrared low-emissivity material has a reflection effect in the 2-20 mu m infrared band and a direct transmission effect in the 100 kHz-1.6 THz communication electromagnetic wave band.The radio electromagnetic wave high-transmission infrared low-emissivity material comprises a scattering body.The present application has the advantages of solving the problems of electromagnetic shielding effect and limited application of the existing low-emissivity material, simple preparation method, and application of the material in the fields of new energy vehicles, low-carbon energy-saving buildings, cold-chain logistics, low-carbon agriculture, smart cities, and infrared thermal camouflage of radiation heat insulation and compatible multi-band stealth technology, and has a good application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of functional new materials, and particularly relates to an infrared low-emissivity material with high transmission of radio electromagnetic waves and a preparation method thereof. BACKGROUND

[0002] Infrared thermal radiation is an important energy and information transmission carrier. Any object above absolute zero in nature will radiate energy in the form of electromagnetic waves. At room temperature and medium-high temperature, the objects in daily life mainly radiate in the 2-20 μm mid-infrared band. Infrared thermal radiation has wide application and great significance in the fields of infrared camouflage, thermal photovoltaic systems, night imaging, thermal regulation, etc.

[0003] Radiation temperature control is to change the radiation characteristics of an object in the environment by constructing the spectral characteristics of a specific wave band, and then to change the temperature of the object to achieve low-energy heat management. The building industry currently accounts for about 40% of global primary energy consumption, more than 50% of which is used for heating, ventilation and air conditioning systems. Existing temperature control designs are mainly based on thermal conduction and heat convection to achieve temperature control, and rarely involve thermal radiation regulation. However, the heat consumed by the human body and the building through thermal radiation accounts for about half of the total heat. Some designs are based on thermal radiation for heat management, but the surface low-emissivity materials used in existing designs are metals or metal oxides, which cannot balance "infrared low-emissivity thermal insulation and energy saving" and "effective transmission of communication information", making the existing infrared low-emissivity temperature control materials greatly limited in application. Especially in the context of new energy vehicles, low-carbon energy-saving buildings, cold-chain logistics, smart cities realizing networking, intelligentization and digitization, 5G and 6G communication technology upgrading, it is difficult to play a role.

[0004] Infrared low-emissivity materials can not only be applied to radiation temperature control, but also are widely concerned in the field of thermal infrared camouflage. Thermal infrared camouflage mainly reduces the radiant energy or radiation temperature of the target object to hide the true temperature of the object, thereby avoiding the object from being detected by infrared detection equipment. Commonly used infrared detection equipment works in the 3-5 μm and 8-14 μm wave bands, and thermal infrared camouflage is also mainly for these two wave bands. One way to achieve thermal infrared camouflage is to adjust the emissivity. In the case that the temperature of the object remains unchanged, reducing the emissivity will reduce the thermal radiation energy of the object and reduce the possibility of the object being identified by the infrared detection device, thereby achieving infrared thermal camouflage. The infrared stealth technology of weapon equipment requires balance and comprehensive design with other stealth technologies (radar stealth, etc.). However, metal or metal oxide low-emissivity materials have high reflectivity in the 2-18 GHz wave band commonly used by radar detection systems, and cannot balance infrared stealth and radar stealth.

[0005] Therefore, it is of great significance to realize infrared thermal insulation materials with the characteristics of "wide-band infrared low emissivity" and "low electromagnetic signal attenuation" for the deep integration of the dual-carbon strategy core technology represented by low-carbon buildings and new energy vehicles with the next generation of information technology, and it has important value for realizing the compatibility of multi-band stealth technology such as infrared thermal camouflage and radar millimeter wave stealth. SUMMARY

[0006] The present application provides a kind of infrared low emissivity material of wireless electromagnetic wave high transmission and preparation method thereof to solve the above problems.

[0007] The first object of the present application is to provide an infrared low emissivity material with high transmission of wireless electromagnetic waves, which has a reflective effect in the 2-20 μm infrared band and a direct transmission effect in the 100 kHz-1.6 THz communication electromagnetic wave band; the infrared low emissivity material with high transmission of wireless electromagnetic waves comprises scatterers.

[0008] Preferably, the infrared low emissivity material with high transmission of wireless electromagnetic waves has an average reflectivity of at least 40% in the 2-20 μm infrared band and a transmission rate of at least 40% in the 100 kHz-1.6 THz communication electromagnetic wave band.

[0009] Preferably, the scatterers are constructed by non-metallic infrared low emissivity materials and air, or by at least two non-metallic infrared low emissivity materials; the scatterers have a regular or irregular cylindrical, pyramidal, spherical or strip shape.

[0010] Preferably, the scatterers are constructed by non-metallic infrared low emissivity materials and air, and the construction method is to construct air holes with a diameter of 0.2-50 μm in the non-metallic infrared low emissivity material to form the scatterers, or to construct non-metallic infrared low emissivity particles with a size of 0.2-50 μm in the air to form the scatterers.

[0011] Preferably, the scatterers are constructed by at least two non-metallic infrared low emissivity materials, and the construction method is to use two or more non-metallic infrared low emissivity materials with different refractive indices to prepare the scatterers, wherein one of the non-metallic infrared low emissivity materials is non-metallic infrared low emissivity particles with a particle size of 0.2-50 μm.

[0012] Preferably, the non-metallic infrared low emissivity material is at least one of an infrared transparent crystal and an infrared transparent polymer;

[0013] The infrared transparent crystal is at least one of sodium chloride, potassium chloride, potassium bromide, zinc sulfide, calcium fluoride, magnesium fluoride, cesium iodide, zinc selenide, zinc sulfide, diamond, sapphire, barium fluoride, cesium bromide, fused quartz, lithium fluoride, silver bromide, silver chloride;

[0014] The infrared transparent polymer is at least one of polyethylene, polyethylene and polystyrene copolymer, polypropylene, silicone rubber, butyl rubber, ethylene-propylene-diene rubber, acrylic resin, alkyd resin, epoxy resin, polyurethane, polytetrafluoroethylene, hydrogenated styrene-butadiene block copolymer, ethylene-butene tri-block copolymer, polyolefin, and tyrosine tripeptide.

[0015] The second object of the present application is to provide a preparation method of the infrared low-emissivity material with high radio electromagnetic wave transmission, which specifically comprises the following steps: uniformly mixing the scatterer, the adhesive and the solvent to form a scatterer-adhesive-solvent dispersion liquid; the mass ratio of the scatterer and the adhesive is 50wt%-100wt% of the scatterer and 0wt%-50wt% of the adhesive; and the mass ratio of the solvent to the sum of the mass of the scatterer and the adhesive is 1-8:2.

[0016] The scatterer-adhesive-solvent dispersion liquid is uniformly coated on the substrate with a thickness of 0.05-10mm; and a film layer structure is formed after solidification, that is, the infrared low-emissivity material with high radio electromagnetic wave transmission.

[0017] Preferably, the solvent is any one of tetrahydrofuran, n-hexane, acetone, water, ethanol, dichloromethane, trichloromethane or toluene; and the adhesive is at least one of polyethylene, polyethylene and polystyrene copolymer, polypropylene, silicone rubber, butyl rubber, ethylene-propylene-diene rubber, acrylic resin, alkyd resin, epoxy resin, polyurethane, polytetrafluoroethylene, hydrogenated styrene-butadiene block copolymer, ethylene-butene tri-block copolymer, polyolefin and tyrosine tripeptide.

[0018] The third object of the present application is to provide a preparation method of the infrared low-emissivity material with high radio electromagnetic wave transmission, which specifically comprises the following steps: pressing the scatterer into a test cake; and cooling the test cake to room temperature after high-temperature sintering, so as to obtain the infrared low-emissivity material with high radio electromagnetic wave transmission.

[0019] Preferably, the pressing pressure of the test cake is 1-20MPa; and the high-temperature sintering condition is that the heating rate is 1-15℃ / min, the sintering temperature is 200-2000℃, and the holding time is 30-180min.

[0020] Compared with the prior art, the present application can achieve the following beneficial effects:

[0021] (1) The preparation process of the infrared low-emissivity material with high radio electromagnetic wave transmission is simple, and the material can be obtained through a simple process method.

[0022] (2) The preparation method can make the obtained radio electromagnetic wave high-transmittance infrared low-emissivity material have an infrared average reflectivity of > 50% in a 2-20 mu m wave band and a communication electromagnetic wave band 100 kHz-1.6 THz transmittance of > 50%, and solves the problems of electromagnetic shielding effect and limited application of the existing low-emissivity material. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a particle size distribution diagram of the micron sodium chloride crystal particles provided according to the embodiment 1 of the present application;

[0024] Figure 2 is a macroscopic photo of large-scale preparation of the radio electromagnetic wave high-transmittance infrared low-emissivity material provided according to the embodiment 1 of the present application;

[0025] Figure 3 is a reflectivity / transmittance spectrum diagram of the radio electromagnetic wave high-transmittance infrared low-emissivity material provided according to the embodiment 1 of the present application; in the diagram, A is a visible light reflection spectrum, B is an infrared reflectivity spectrum, and C is a 300 kHz-40 GHz and 0.1 THz-1.6 THz electromagnetic wave transmittance spectrum;

[0026] Figure 4 is a temperature change diagram of the heat preservation and insulation performance test of the radio electromagnetic wave high-transmittance infrared low-emissivity material provided according to the embodiment 1 of the present application;

[0027] Figure 5 is a cold chain transportation insulation box simulation experiment result diagram of the radio electromagnetic wave high-transmittance infrared low-emissivity material provided according to the embodiment 1 of the present application;

[0028] Figure 6 is a 26 GHz wireless video transmission experiment result diagram of the radio electromagnetic wave high-transmittance infrared low-emissivity material provided according to the embodiment 1 of the present application; in the diagram, A is a constellation diagram of a receiving end wireless signal when there is no any obstacle between a transmitting antenna and a receiving antenna; B is a constellation diagram of a receiving end wireless signal when the thermal radiation material in the embodiment 1 is placed between the transmitting antenna and the receiving antenna; and C is a constellation diagram of a receiving end wireless signal when a commercial aluminum foil heat preservation material is placed between the transmitting antenna and the receiving antenna;

[0029] Figure 7 is a wireless charging experiment result diagram of the radio electromagnetic wave high-transmittance infrared low-emissivity material provided according to the embodiment 1 of the present application; in the diagram, A is a charging condition diagram when a mobile phone is directly placed on a wireless charger; B is a charging condition diagram when the thermal radiation material in the embodiment 1 is placed between the mobile phone and the wireless charger; and C is a charging condition diagram when a metal aluminum foil is placed between the mobile phone and the wireless charger;

[0030] Figure 8is a result picture of a terahertz imaging experiment using the infrared low-emissivity material with high radio electromagnetic wave transmittance according to the present application embodiment 1, in which, A is a top view of the article in the bag, B is a terahertz imaging result picture of the thermal insulation bag prepared using the embodiment 1, and C is a terahertz imaging result picture of the thermal insulation bag using the commercial aluminum foil;

[0031] Figure 9 is an infrared reflectivity spectrum of the infrared low-emissivity material with high radio electromagnetic wave transmittance provided according to the present application embodiment 2;

[0032] Figure 10 is an infrared reflectivity spectrum of the infrared low-emissivity material with high radio electromagnetic wave transmittance provided according to the present application embodiment 3;

[0033] Figure 11 is an infrared reflectivity spectrum of the infrared low-emissivity material with high radio electromagnetic wave transmittance provided according to the present application embodiment 4 and embodiment 5. DETAILED DESCRIPTION

[0034] Hereinafter, embodiments of the present application will be described with reference to the accompanying drawings. In the following description, the same modules are denoted by the same reference numerals. In the case of the same reference numerals, their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated.

[0035] In order to make the objects, technical solutions, and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not constitute a limitation on the present application.

[0036] The present application provides an infrared low-emissivity material with high radio electromagnetic wave transmittance, comprising a scatterer, the infrared low-emissivity material with high radio electromagnetic wave transmittance has a reflection effect in the infrared waveband of 2-20 μm and has a direct transmission effect in the communication electromagnetic waveband of 100 kHz-1.6 THz; preferably, the infrared low-emissivity material with high radio electromagnetic wave transmittance has a reflection effect in the infrared waveband of 2-14 μm;

[0037] The material has an average reflectivity of at least 40% in the infrared waveband of 2-20 μm and a transmittance of at least 40% in the communication electromagnetic waveband of 100 kHz-1.6 THz;

[0038] The scatterer is constructed by a non-metal infrared low-emissivity material and air, or is constructed by at least two non-metal infrared low-emissivity materials, and has a low emissivity in the infrared waveband; the shape of the constructed scatterer can be regular or irregular, including a column, a pyramid, a sphere, a strip, and irregular columns, pyramids, spheres, strips, etc.;

[0039] When the scatterer is constructed by non-metal infrared low emissivity material and air, the construction method is: constructing air holes with a diameter of 0.2-50 μm in the non-metal infrared low emissivity material to form the scatterer, or constructing non-metal infrared low emissivity particles with a size of 0.2-50 μm in the air to form the scatterer;

[0040] When the scatterer is constructed by at least two non-metal infrared low emissivity materials, the construction method is: preparing the scatterer by using two or more non-metal infrared low emissivity materials with different refractive indexes; one of the non-metal infrared low emissivity materials is non-metal infrared low emissivity particles with a particle size of 0.2-50 μm;

[0041] The non-metal infrared low emissivity material is at least one of infrared transparent crystal and infrared transparent polymer;

[0042] The infrared transparent crystal is at least one of non-metal infrared transparent crystal such as sodium chloride, potassium chloride, potassium bromide, zinc sulfide, calcium fluoride, magnesium fluoride, cesium iodide, zinc selenide, zinc sulfide, diamond, sapphire, barium fluoride, cesium bromide, fused quartz, lithium fluoride, silver bromide, silver chloride, etc.

[0043] The infrared transparent polymer is at least one of polyethylene, polyethylene and polystyrene copolymer, polypropylene, silicone rubber, butyl rubber, ethylene-propylene-diene rubber, acrylic resin, alkyd resin, epoxy resin, polyurethane, polytetrafluoroethylene, hydrogenated styrene-butadiene block copolymer, polyolefin, and tyrosine tripeptide.

[0044] A preparation method of an infrared low emissivity material with high radio wave permeability, comprising the following steps: uniformly mixing a scatterer, an adhesive and a solvent to form a scatterer-adhesive-solvent dispersion liquid; uniformly spreading the scatterer-adhesive-solvent dispersion liquid on a substrate to a thickness of 1-5 mm; and curing the coating layer to form a film layer structure, i.e. the infrared low emissivity material with high radio wave permeability; in a specific embodiment, the curing is performed after the material is placed at room temperature (15-25°C) for 10-20 hours.

[0045] The mass ratio of the scatterer and the adhesive is 80wt%-100wt% of the scatterer and 0wt%-20wt% of the adhesive; the ratio of the mass of the solvent to the sum of the mass of the scatterer and the mass of the adhesive is 1-3:1; the solvent is any one of tetrahydrofuran, n-hexane, acetone or toluene; the adhesive is any one of a three-embedded copolymer material (consisting of polystyrene and ethylene-butene copolymer, abbreviated as SEBS), polyethylene (PE) and polytetrafluoroethylene (PTFE) infrared low emissivity organic matter, dissolved in the solvent.

[0046] A preparation method of an infrared low-emissivity material with high radio wave permeability, comprising the following steps: putting scatterers into a mold to press into a test cake; cooling the test cake to room temperature after high-temperature sintering, to obtain an infrared high-reflection, high-transmission radio wave material, i.e., an infrared low-emissivity material with high radio wave permeability.

[0047] The pressure for pressing the test cake is 1-20 MPa; the high-temperature sintering is performed at a temperature rising rate of 1-15 ℃ / min, a sintering temperature of 200-2000 ℃, and a holding time of 30-180 min; preferably, the pressure for pressing the test cake is 4-20 MPa; the high-temperature sintering is performed at a temperature rising rate of 2-10 ℃ / min, a sintering temperature of 450-600 ℃, and a holding time of 90-150 min.

[0048] Example 1

[0049] A preparation method of an infrared low-emissivity material with high radio wave permeability, comprising the following steps: uniformly mixing scatterers, a binder, and an organic solvent to form a scatterer-binder-organic solvent dispersion liquid; specifically, the scatterer is sodium chloride crystals with a size of 0.5-20 microns, the binder is SEBS, the ratio of the scatterer to the binder is 95 wt% of sodium chloride crystals and 5 wt% of SEBS, and the organic solvent is tetrahydrofuran with a mass of 200% of the sum of the mass of the scatterer and the binder. First, SEBS is dissolved in tetrahydrofuran, and the mixture is stirred magnetically at room temperature for 12 hours until it is uniformly mixed, then micron-sized NaCl particles are added, and the mixture is continuously stirred for 2 hours until it is uniformly mixed, to form a NaCl-SEBS-tetrahydrofuran dispersion liquid.

[0050] The scatterer-binder-organic solvent dispersion liquid is scraped onto a substrate using a scraper to form a 2-mm-thick NaCl-SEBS-tetrahydrofuran dispersion liquid on PE; after 12 hours at room temperature, the tetrahydrofuran is completely volatilized, the sample is solidified, and a 850-μm-thick porous structure thin film coating, i.e., an infrared low-emissivity material with high radio wave permeability, is formed.

[0051] This embodiment demonstrates the preparation of an infrared low-emissivity material with high radio and microwave wave transmission by utilizing the principle of medium scattering. Compared with commercial thermal insulation materials, the infrared low-emissivity material can save indoor heating energy consumption, reduce the consumption of refrigeration materials for cold chain transportation, and support WIFI wireless video information transmission, wireless charging, and cold chain logistics terahertz security imaging application scenarios, due to its high infrared reflectance of over 90% and high radio and microwave wave transmission of over 70%. Due to its excellent infrared heat radiation suppression and high radio and microwave wave transmission characteristics, the infrared low-emissivity material is expected to replace the traditional metal thermal insulation material with strong electromagnetic shielding effect, meeting the social demand for "thermal comfort thermal insulation" and "high communication quality smart city of everything".

[0052] A thermal insulation test device was built using a tin box and thermal insulation polystyrene foam. The size of the tin box was 40 cm x 25 cm x 24 cm. The radio and microwave wave transmission infrared low-emissivity material prepared in Example 1 was coated on the inner and outer surfaces of the tin box. A thermocouple was suspended and attached to the inside of the box to measure the temperature inside the box. The control group was a tin box coated with commercial white paint on the inner and outer surfaces. A thermocouple was suspended and attached to the same position inside the box to measure the temperature inside the box. The tin box was placed on the thermal insulation foam, and the device was placed on the ground outside. The thermocouple was used to record the ambient temperature and ground temperature.

[0053] Using the tin box coated with the thermal radiation material on the inner and outer surfaces, the control group was a white paint box and a tin box coated with commercial aluminum foil thermal insulation material on the inner and outer surfaces, a cold chain transportation insulation box simulation experiment was conducted. Under the hot outdoor conditions in summer, the same mass of ice was placed in the thermal radiation material box, the white paint box, and the aluminum foil thermal insulation box, respectively, and the melting rate of the ice in the box was recorded.

[0054] A wireless communication system was built to conduct a wireless signal transmission experiment. The wireless communication system used QPSK modulation technology to encode a video signal into a 26 GHz radio electromagnetic signal, which was transmitted from the transmitting antenna end to the receiving antenna end at a rate of 357 Kbps. Between the transmitting antenna and the receiving antenna, the following conditions were set: no obstacles, placement of the radio and microwave wave transmission infrared low-emissivity material in Example 1, and placement of commercial aluminum foil thermal insulation material. The constellation diagram of the received signal was recorded under the three conditions to represent the quality of wireless signal transmission.

[0055] A wireless charging experiment was conducted using a wireless charger. The wireless electromagnetic wave frequency emitted by the wireless charger was 100-148.5 kHz, and the mobile phone used supported a wireless charging power of up to 27 W. Between the wireless charger and the mobile phone, the following conditions were set: no obstacles, placement of the thermal radiation material in Example 1, and placement of aluminum foil. The charging condition of the mobile phone under the three conditions was recorded.

[0056] A terahertz imaging experiment was performed using a terahertz security imaging system. The working frequency of the terahertz security imaging system was 35 GHz. The infrared low-emissivity material with high radio electromagnetic wave transmittance was prepared in a non-woven bag, and a commercial aluminum foil thermal insulation bag was used as a control group. Fruits, canned cola, metal toy guns and other objects were placed in the thermal insulation bags of Example 1 and the control commercial aluminum foil thermal insulation bag, and the terahertz security imaging system was used to perform security imaging on the objects in the thermal insulation box.

[0057] As shown in Figure 1 The scanning electron microscope photograph of the micrometer sodium chloride crystal particles in Example 1 of the present application is shown, which shows that the size of the micrometer sodium chloride crystal particles is 0.5-20 μm.

[0058] As shown in Figure 2 The macro photograph of the large-scale preparation of the infrared low-emissivity material with high radio electromagnetic wave transmittance in Example 1 of the present application is shown, which shows that the material has a white appearance, and the material has good fluidity, universality, easy processability, etc.

[0059] As shown in Figure 3 The reflectance spectrum of the infrared low-emissivity material with high radio electromagnetic wave transmittance in Example 1 of the present application under the sunlight waveband (0.2-2.5 μm) is shown in A of FIG. 6, and the average solar reflectance of the material reaches 97.9%; the reflectance spectrum of the material under the mid-infrared waveband (2.5-20 μm) is shown in B of FIG. 6, and the average infrared reflectance of the material in the range of 2.5-14 μm reaches 85.2%. As shown in Figure 3 The transmittance of the material in the communication electromagnetic waveband (1-40 GHz) reaches more than 80%. Both sodium chloride and SEBS are infrared low-emissivity materials, and have very low absorption of infrared radiation in the range of 2.5-20 μm. Due to Mie scattering, the scattering body of the sodium chloride crystal particles in the size range of 0.5-20 μm can strongly scatter sunlight and mid-infrared light, so that the material has high reflectivity in the waveband of 0.2-20 μm, and reflects solar radiation energy and near-infrared-mid-infrared radiation, which meets the optical requirements of radiation thermal insulation. At the same time, the material does not contain metal or metal oxide, and the dielectric material has high transmittance of electromagnetic waves in the communication waveband, which meets the electromagnetic requirements of various communication scenes.

[0060] Figure 4The diagram illustrates the temperature variation during a test of the thermal insulation performance of the infrared-low emissivity material with high radio electromagnetic wave transmittance in Embodiment 1 of the present invention. Under outdoor conditions, compared to a commercially available white-painted metal box, the metal box covered with the thermal radiation material exhibits a lower internal temperature during sunny, warm days and at night when temperatures are lower. Throughout the day, the metal box covered with the thermal radiation material has a cooling effect on high-temperature environments and a heat-insulating effect on low-temperature environments, demonstrating better stability against outdoor temperature changes and reducing the energy consumption of HVAC systems required to maintain a constant indoor temperature.

[0061] Figure 5 The diagram shows the simulation results of an insulated box for cold chain transportation made of infrared low emissivity material with high radio electromagnetic wave transmittance according to Embodiment 1 of the present invention. Under hot outdoor conditions in summer, compared with commercial white paint boxes and commercial aluminum foil insulation boxes, the thermal radiation material in Embodiment 1 can reduce the melting rate of ice inside the box. This demonstrates that infrared low emissivity material with high radio electromagnetic wave transmittance can reduce the amount of refrigeration material used in cold chain transportation scenarios.

[0062] Figure 6 The diagram shows the experimental results of 26GHz wireless video transmission using the infrared low emissivity material with high radio electromagnetic wave transmittance according to Embodiment 1 of the present invention. When there are no obstacles between the transmitting and receiving antennas, the constellation diagram of the wireless signal at the receiving end is as follows. Figure 6 As shown in Figure A, the points in the constellation diagram are dispersed and stable, allowing for correct demodulation of the bit information transmitted by the transmitter, and ensuring normal video transmission. When the thermal radiation material from Example 1 is placed between the transmitting and receiving antennas, the constellation diagram of the receiving wireless signal is as follows. Figure 6 As shown in Figure B, the points in the constellation diagram are dispersed and stable, allowing for correct demodulation of the bit information transmitted by the transmitter, and ensuring normal video transmission. When commercial aluminum foil insulation material is placed between the transmitting and receiving antennas, the constellation diagram of the receiving wireless signal is as follows. Figure 6 As shown in Figure C, the constellation diagram is disordered, making it impossible to demodulate the bit information transmitted by the transmitter, and video transmission fails. Experimental results show that the infrared low emissivity material with high radio electromagnetic wave transmittance in Embodiment 1 of this invention has superior radio electromagnetic wave transmittance, enabling high-quality wireless communication.

[0063] Figure 7 This is a diagram showing the experimental results of wireless charging using a material with high radio electromagnetic wave transmittance and low infrared emissivity, as provided in Embodiment 1 of the present invention. When the mobile phone is placed directly on the wireless charger, as... Figure 7 As shown in Figure A, it can charge normally, and the phone screen displays a charging power of 27W; when the thermal radiation material in Example 1 is placed between the phone and the wireless charger, as... Figure 7As shown in the middle B, the wireless charging can still be performed, and the power is 27W; when the metal aluminum foil is placed between the mobile phone and the wireless charger, as shown in Figure 7 As shown in the middle C, the charging cannot be performed.

[0064] Figure 8 is a result map of a terahertz imaging experiment according to the present application embodiment 1 using the infrared low-emissivity material with high transmission of wireless electromagnetic waves. Figure 8 As shown in the middle A, the fruits, canned cola, metal toy gun and other items placed in the bag are shown in the top view. When the commercial aluminum foil insulation bag is imaged for security inspection using the terahertz imaging instrument, as shown in Figure 8 As shown in the middle C, due to the shielding effect of the aluminum foil, the items in the bag cannot be detected, and therefore the box needs to be opened for security inspection, resulting in temperature change. When the security inspection is performed using the insulation bag of embodiment 1, as shown in Figure 8 As shown in the middle B, the terahertz imaging map of the fruits, canned cola, metal toy gun and other items in the bag is clear. When the insulation bag prepared using the infrared low-emissivity material with high transmission of wireless electromagnetic waves is used, the security inspection and detection without opening the box are supported, and the cold chain storage, security inspection and transportation are all insulated.

[0065] Embodiment 2

[0066] A preparation method of an infrared low-emissivity material with high transmission of wireless electromagnetic waves, comprising the following steps: uniformly mixing a scatterer, an adhesive and an organic solvent to form a scatterer-adhesive-organic solvent dispersion liquid; specifically, the preferred scatterer is a micrometer sodium chloride crystal, the size of the micrometer sodium chloride crystal is 0.5-20 micrometers, and the adhesive is SEBS; the ratio of the scatterer to the adhesive is: 82wt% of sodium chloride crystal and 18wt% of SEBS. The organic solvent is n-hexane, and the mass of the organic solvent is 300% of the sum of the masses of the scatterer and the adhesive. First, the SEBS is dissolved in the n-hexane, and the mixture is uniformly stirred at room temperature for 12 hours, then the micrometer NaCl particles are added, and the mixture is continuously stirred for 2 hours to form a NaCl-SEBS-n-hexane dispersion liquid.

[0067] The NaCl-SEBS-n-hexane dispersion liquid is scraped and coated on the PE substrate by using a scraper, and the scraping thickness is 2mm. After 12 hours at room temperature, the n-hexane is completely volatilized, the sample is solidified, and a 850μm thick coating layer, i.e. the infrared low-emissivity material with high transmission of wireless electromagnetic waves, is formed.

[0068] As shown in Figure 9 The infrared high-reflection, high-transmission electromagnetic wave band thermal radiation coating in the present application embodiment 2 has a reflection spectrum in the middle infrared wave band (2.5-20μm).

[0069] Embodiment 3

[0070] A preparation method of an infrared low-emissivity material with high radio electromagnetic wave transmittance, comprising the following steps: putting scattering bodies into a mold to press into a test cake; and cooling the test cake to room temperature after high-temperature sintering, so as to obtain the infrared low-emissivity material with high radio electromagnetic wave transmittance.

[0071] Specifically, the scattering bodies are micro sodium chloride crystals, and the size of the micro sodium chloride crystals is 0.5-20 microns. First, the micro sodium chloride crystal powder is put into a cylindrical mold with a diameter of 80 mm, and the micro sodium chloride crystal powder is pressed into a cylindrical test cake with a diameter of 8 mm under a pressure of 4 MPa; the test cake is put into a tube furnace, the temperature is raised from room temperature to 500 DEG C at a rate of 10 DEG C / min, and after maintaining the high temperature of 500 DEG C for 120 min, the heating is stopped and the temperature is naturally lowered to room temperature, and the test cake is taken out, so as to obtain the infrared low-emissivity material with high radio electromagnetic wave transmittance.

[0072] As shown in FIG. 3, the reflectance spectrum of the infrared low-emissivity material with high radio electromagnetic wave transmittance in the embodiment 3 of the present application in the mid-infrared wave band (2.5-20 microns) is shown. Figure 10 The average infrared reflectivity of the coating in the range of 2.5-14 microns reaches 92.2%.

[0073] Embodiment 4

[0074] A preparation method of an infrared low-emissivity material with high radio electromagnetic wave transmittance, comprising the following steps: putting scattering bodies into a mold to press into a test cake; and cooling the test cake to room temperature after high-temperature sintering, so as to obtain the infrared low-emissivity material with high radio electromagnetic wave transmittance.

[0075] Specifically, the scattering bodies are micro sodium chloride crystals, and the size of the micro sodium chloride crystals is 0.5-20 microns. First, the micro sodium chloride crystal powder is put into a cylindrical mold with a diameter of 80 mm, and the micro sodium chloride crystal powder is pressed into a cylindrical test cake with a diameter of 8 mm under a pressure of 4 MPa; the test cake is put into a tube furnace, the temperature is raised from room temperature to 500 DEG C at a rate of 10 DEG C / min, and after maintaining the high temperature of 500 DEG C for 120 min, the heating is stopped and the temperature is naturally lowered to room temperature, and the test cake is taken out, so as to obtain the infrared low-emissivity material with high radio electromagnetic wave transmittance.

[0076] As shown in FIG. 4, the reflectance spectrum of the infrared low-emissivity material with high radio electromagnetic wave transmittance in the embodiment 4 of the present application in the mid-infrared wave band (2.5-20 microns) is shown. Figure 11 The average infrared reflectivity of the coating in the range of 2.5-14 microns reaches 92.2%.

[0077] Embodiment 5

[0078] The application discloses a preparation method of an infrared low-emissivity material with high radio electromagnetic wave permeability.

[0079] Specifically, the scattering body is micron sodium chloride crystals, preferably, the proportion of the scattering body is 100%, and preferably, the size of the micron sodium chloride crystals is 0.2-5 mu m. First, the micron sodium chloride crystal powder is placed in a cylindrical mold with a diameter of 80 mm, and the micron sodium chloride crystal powder is pressed into a cylindrical test cake with a diameter of 8 mm under a pressure of 4 MPa; the test cake is placed in a tube furnace, the temperature is raised from room temperature to 500 DEG C at a rate of 10 DEG C / min, and after maintaining the high temperature of 500 DEG C for 120 min, the heating is stopped and the temperature is naturally lowered to room temperature, and the test cake is taken out, thereby obtaining the infrared low-emissivity material with high radio electromagnetic wave permeability.

[0080] As shown in Figure 11 The reflectance spectrum of the infrared low-emissivity material with high radio electromagnetic wave permeability in the embodiment 5 of the application in the mid-infrared wave band (2.5-20 mu m) is shown.

[0081] The material can be applied in the fields of radiation refrigeration, radiation heating and thermal radiation camouflage, applied in the fields of radiation heat preservation and insulation and compatible multi-band stealth infrared thermal camouflage of new energy vehicles, low-carbon energy-saving buildings, cold chain logistics, low-carbon agriculture, smart cities, and has good application prospect. Specifically, by the principle of medium scattering, a non-metal infrared low-emissivity material and air are used to construct a scattering body, an infrared low-emissivity material with high radio electromagnetic wave permeability is prepared, the characteristics of "wide-band infrared low-emissivity high reflectivity" and "low electromagnetic signal attenuation" are realized, the problem that the existing infrared low-emissivity material is incompatible with "infrared low-emissivity" and "high radio wave permeability" is overcome, and the deep integration of the core technology of the double-carbon strategy represented by low-carbon buildings and new energy vehicles and the next generation of information technology has important significance, and the compatibility of infrared thermal camouflage and radar millimeter wave stealth and other multi-band stealth technologies has important value.

[0082] It should be understood that the various forms of flow shown above can be used to reorder, add or delete steps. For example, the steps described in the present application can be executed in parallel, in sequence or in different order, as long as the desired results of the technical solutions of the present application can be achieved, and the present application does not limit this.

[0083] The above detailed description does not limit the scope of the application. Various modifications, combinations, sub-combinations and alternatives can be made to the detailed description. Any modification, equivalent replacement and improvement etc. made within the spirit and principle of the application shall be included in the scope of the application.

Claims

1. An infrared low emissivity material with high transmission of radio electromagnetic waves, characterized in that: The radio electromagnetic wave high-transmittance and infrared low-emissivity material has an infrared average reflectivity of at least 40% in a 2-20-micron wave band and a transmittance of at least 40% in a communication electromagnetic wave band of 100 kHz-1.6 THz; the radio electromagnetic wave high-transmittance and infrared low-emissivity material comprises scatterers; the scatterers have shapes of regular or irregular cylinders, pyramids, spheres or strips; and the scatterers are constructed by non-metal infrared low-emissivity materials and air or by at least two non-metal infrared low-emissivity materials. The scatterers are constructed by non-metal infrared low-emissivity materials and air, and the construction method is as follows: non-metal infrared low-emissivity particles with a size of 0.2-50 microns are constructed in air to form the scatterers; the scatterers are pressed into a test cake; and the test cake is sintered at a high temperature and then cooled to room temperature, wherein the test cake is pressed at a pressure of 1-20 MPa; the high-temperature sintering is performed at a temperature rising rate of 1-15 ℃ / min, a sintering temperature of 200-2000 ℃ and a holding time of 30-180 min. The radio electromagnetic wave high-transmittance and infrared low-emissivity material is constructed by at least two non-metal infrared low-emissivity materials, and the construction method specifically comprises the following steps: uniformly mixing the scatterers, SEBS and a solvent to form a scatterer-adhesive-solvent dispersion liquid, placing the dispersion liquid at room temperature for 10-20 hours for solidification, and forming a film layer structure after solidification; the mass ratio of the scatterers and SEBS is 82 wt%-100 wt% of the scatterers and 0 wt%-18 wt% of SEBS, and SEBS is not 0 wt%; the mass ratio of the solvent to the sum of the masses of the scatterers and the adhesive is 1-8:2; and the non-metal infrared low-emissivity material is non-metal infrared low-emissivity particles with a particle size of 0.2-20 microns.

2. The infrared low emissivity material of claim 1, wherein: the infrared low emissivity material has a transmittance of 70% or more for a radio electromagnetic wave having a frequency of 100 MHz or more and a wavelength of 3 m or less. The non-metal infrared low-emissivity material is an infrared transparent crystal. The infrared transparent crystal is at least one of sodium chloride, potassium chloride, potassium bromide, zinc sulfide, calcium fluoride, magnesium fluoride, cesium iodide, zinc selenide, diamond, sapphire, barium fluoride, cesium bromide, fused quartz, lithium fluoride, silver bromide and silver chloride.

3. A method for preparing an infrared low emissivity material with high radio electromagnetic wave transmission according to any one of claims 1-2, characterized in that: The scatterer-adhesive-solvent dispersion liquid is uniformly coated on a substrate to a thickness of 0.05-10 mm, and a film layer structure, i.e., the radio electromagnetic wave high-transmittance and infrared low-emissivity material, is formed after solidification.

4. The method of claim 3, wherein the infrared low emissivity material having high transparency to radio electromagnetic waves is prepared by the steps of: (a) preparing a first layer on a substrate; (b) preparing a second layer on the first layer; and (c) preparing a third layer on the second layer. The solvent is any one of tetrahydrofuran, n-hexane, acetone, water, ethanol, dichloromethane, trichloromethane or toluene.

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