Silver ant-like radiative refrigeration villus structure and preparation method and application thereof

Abstract

The present application relates to a kind of silver ant imitation radiation refrigeration fluff structure and its preparation method and application, the silver ant imitation radiation refrigeration fluff structure is made of multiple short fibers of silk in array distribution, the bottom of each short fiber of silk is vertically fixed on substrate surface, top is connected to form a fiber layer, and air layer is formed between fiber layer and substrate;The thickness of silver ant imitation radiation refrigeration fluff structure is 1-3mm;Its preparation method is: using electrostatic flocking method, short fiber of silk is flocked on the surface of substrate with adhesion, and silver ant imitation radiation refrigeration fluff structure is prepared;The silver ant imitation radiation refrigeration fluff structure of the present application can be applied to clothing and textile, wearable electronic products, cooler, automobile, outdoor tent and building exterior wall cooling refrigeration.The present application utilizes the triangular cross section of silk and electrostatic flocking technology to prepare bionic structure, realizes effective radiation cooling effect, and overcomes the difficulty that radiation refrigeration material is difficult to apply in personal cooling management.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of radiation refrigeration, and relates to a silver ant-like radiation refrigeration fluff structure and a preparation method and application thereof. BACKGROUND

[0002] Reducing energy consumption is the key to sustainable development. Since temperature regulation for human comfort consumes a large amount of energy, at present, research on temperature regulation without any energy consumption has attracted widespread attention. Radiation refrigeration refers to a refrigeration mode that realizes cooling by emitting infrared radiation to the atmospheric transparent window (8-13 μm) to the maximum extent. At present, after realizing the absorption of as little solar spectrum as possible and increasing the emission of the atmospheric window, the radiation refrigeration material has developed from night-time radiation refrigeration to daytime radiation refrigeration. The key to daytime radiation refrigeration lies in the reflectivity and emissivity of the surface of the regulation material. By increasing the reflectivity of the material surface in the solar spectrum and the emissivity in the waveband transparent to the atmosphere, the purpose of cooling is achieved by realizing that the absorbed energy is less than the radiation energy in the daytime.

[0003] At present, research on materials with radiation refrigeration performance is focused on paint, wood, glass, electrospun film and the like, which can be applied in the field of building industry and the like. However, there are many problems at present. First, the radiation refrigeration materials such as wood and glass can be used for the outer layer of buildings and packaging to realize the cooling performance, but the wood and glass materials have poor mechanical properties, no bending and stretching physical properties, and are difficult to be compounded on a soft substrate to achieve the purpose of cooling. Second, the flexible radiation refrigeration materials such as electrospun film, encapsulated micro-nano particle film and porous film have only a small amount of films researched, but they have poor mechanical properties, poor moisture and air permeability and the like, and are not suitable for personal temperature management. In addition, some radiation refrigeration layers prepared by impregnation and coating and the like need to be filled with particles to improve the reflectivity and emissivity, and the addition of particles makes the dried coating hard and brittle, which cannot guarantee the style of the original substrate. At the same time, the physical appearance of such coating is mostly white or silver, which cannot meet the needs of individualization and aesthetic design.

[0004] Patent application CN 114659290 A discloses a radiation cooling surface based on fiber array and its preparation method and application. The radiation cooling surface in the patent application includes a bottom adhesive layer and a top fiber array structure layer. A large number of nanoparticles are filled in the bottom adhesive layer to improve the reflectivity of the surface to sunlight. However, the diameter of the particles, the filling amount and the thickness of the bottom layer have a great influence on the reflectivity and preparation process of the structure. The reflectivity will decrease due to the excessive or insufficient diameter of the particles, the insufficient filling amount and the insufficient adhesive layer. The thickness of the bottom adhesive layer will affect the firmness and mechanical properties of the flocking structure. Secondly, the fiber array structure composed of white nylon fibers needs the physical properties of the fibers to improve the reflectivity in the visible light region, and the chemical structure to improve the emissivity of infrared light. This covers the physical properties such as color and appearance design of the flocking substrate, and does not require important properties such as the size and structure of the fibers. The patent application indicates that the cooling and refrigeration described therein includes the use as an external wall of a building or a vehicle for sun protection and cooling, condensation of an outdoor water accumulation device, and does not involve the application of radiation cooling materials from a personal perspective.

[0005] Therefore, it is of great significance to study a method for constructing a radiation cooling structure on various types of substrates, which can ensure the characteristics of the substrate itself while achieving similar effects to existing radiation cooling materials only through the structure, making radiation cooling more convenient to apply to different substrates, even to wearable flexible substrates, meeting the comfort requirements of clothing and preserving personalized designs such as appearance. SUMMARY

[0006] In order to solve the problems in the prior art, the present application provides a silver ant-like radiation cooling flocking structure and its preparation method and application.

[0007] To achieve the above-mentioned purposes, the present application adopts the following solutions:

[0008] A silver ant-like radiation cooling flocking structure is composed of a plurality of arrayed silk short fibers. The bottom of each silk short fiber is vertically fixed on the surface of a substrate, and the top is connected to each other to form a randomly stacked fiber layer. An air layer is formed between the fiber layer and the substrate.

[0009] As a preferred technical solution:

[0010] The silver ant-like radiation cooling flocking structure has a thickness of 1-3 mm.

[0011] The present application also provides a preparation method of the silver ant-like radiation cooling flocking structure as described above. The electrostatic flocking method is used to flock the silk short fibers on the surface of a substrate with adhesion to obtain the silver ant-like radiation cooling flocking structure.

[0012] As a preferred technical solution:

[0013] The preparation method of the silver ant imitation radiation cooling fluff structure as described above comprises the following steps:

[0014] (1) preparing silk short fibers with a desired length by physically shearing long silk filaments without degumming treatment;

[0015] (2) degumming the silk short fibers obtained in step (1) to obtain single silk short fibers with a triangular cross section;

[0016] (3) screening the single silk short fibers obtained in step (2) on the cathode plate of an electrostatic flocking device, placing the surface layer with adhesion on the anode plate of the electrostatic flocking device with the adhesion surface facing down, and electrostatic flocking by using a high-voltage electrostatic flocking device;

[0017] (4) curing and drying the product after the electrostatic flocking is completed, and then performing a brush finishing to obtain the silver ant imitation radiation cooling fluff structure.

[0018] In the preparation method of the silver ant imitation radiation cooling fluff structure as described above, the length of the silk short fibers in step (1) is 2-7 mm, and the diameter is 5-15 μm. Different fiber lengths are used to control the thickness of the fluff structure, the thickness affects the spacing between the fibers and the substrate, and changes the refractive properties between the air and the fibers. The relationship between the fiber length and the thickness is as follows: the fluff structure prepared by using the silk short fibers with a fiber length of 2-3 mm has a thickness of about 1 mm; the fluff structure prepared by using the silk short fibers with a fiber length of 4-5 mm has a thickness of about 2 mm; and the fluff structure prepared by using the silk short fibers with a fiber length of 6-7 mm has a thickness of about 3 mm.

[0019] In the preparation method of the silver ant imitation radiation cooling fluff structure as described above, the degumming process in step (2) is boiling degumming of the silk short fibers in a 0.5 wt% sodium carbonate aqueous solution for 30 min, and then rinsing with deionized water at a temperature of 60℃. The boiling degumming and rinsing process are repeated for 3 times, and then the silk short fibers are dried at 60℃.

[0020] In the preparation method of the silver ant imitation radiation cooling fluff structure as described above, the surface layer with adhesion in step (3) is a semi-cured fabric surface, a metal surface, a plastic surface, or a film-forming surface coated with an adhesive.

[0021] In the preparation method of the silver ant imitation radiation cooling fluff structure as described above, the adhesive is one or more of an acrylic composite adhesive, a water-based polyurethane adhesive, an epoxy resin adhesive, and a silicone rubber, and the silicone rubber is preferred; and the semi-curing method is curing at a temperature of 25-100℃ for 5-30 min.

[0022] The preparation method of the silver ant-like radiative cooling fluff structure as described above, the distance between the upper plate and the lower plate in step (3) is 5-30 cm, the voltage of the electrostatic flocking is 5-35 kV, and the electrostatic flocking time is 10-120 s. The flocking density can be controlled by controlling the flocking time. When the flocking time is 10 s, 30 s, 60 s, 90 s and 120 s, the corresponding flocking densities are 2.5 g / m 2 , 5 g / m 2 , 7.5 g / m 2 , 10 g / m 2 and 12.5 g / m 2 .

[0023] The preparation method of the silver ant-like radiative cooling fluff structure as described above, the drying temperature in step (4) is 40-100 DEG C, and the drying time is 0.5-4 h.

[0024] The application also provides the application of the silver ant-like radiative cooling fluff structure as described above, which is applied to the cooling and refrigeration of clothing and textiles, wearable electronic products, coolers, cars, outdoor tents and building outer walls. The silver ant-like radiative cooling fluff structure can realize the radiative cooling effect on various different substrate surfaces, solve the problems of poor flexibility and mechanical properties of the radiative cooling material, ensure the service performance such as moisture permeability and air permeability of the flexible substrate such as fabric and wearable electronic equipment, expand the application range of the radiative cooling material, and realize the functions of no energy consumption and passive cooling.

[0025] The mechanism of the application is as follows:

[0026] In the prior art, wood, glass and other radiative cooling materials are used to realize the surface cooling performance of objects, but are usually limited to the outer layer of buildings and the outer layer of packaging, and are difficult to be compounded on soft substrates to achieve the purpose of cooling. The prior art also has flexible radiative cooling materials such as electrospun films, encapsulated micro-nanoparticle films and porous films, but faces problems such as poor mechanical properties and poor moisture permeability and air permeability, and is not suitable for personal temperature control management. In addition, the prior art also uses impregnation, coating and other methods to prepare a radiative cooling layer, but the addition of particulate matter makes the dried coating hard and brittle, and cannot guarantee the style of the original substrate.

[0027] Unlike the preparation of radiative cooling materials in the prior art, the application intends to construct a radiative cooling structure that can be constructed on various substrates while ensuring the characteristics of the substrate itself, and only through the structure to achieve an effect similar to existing radiative cooling materials, so that the radiative cooling is more convenient to apply on different substrates, even on wearable flexible substrates, to meet the comfort requirements of clothing and to retain personalized designs such as appearance.

[0028] It is found through investigation that short hair structures exist on the surface of some insects in nature, such as the body surface of Saharan silver ants [Keeping cool: Enhanced optical reflection and radiative heat dissipation in Saharan silver ants. Science (J), 349:298], the body surface of Megalobrachium [Biologically inspired flexible photonic films for efficient passive radiative cooling. Proc Natl Acad Sci U S A, 2020. 117(26): p. 14657-14666.], etc. Studies have found that the short hair cross-section of such hair structures is similar to a triangle, which can cause light to reflect and refract on the surface and inside the fiber, reducing the absorption of external energy. At the same time, such structures can increase the thermal radiation of insects outward, and can provide good cooling effect for insects living in hot environment.

[0029] Inspired by this, the present application constructs a silver antler radiation refrigeration fluff structure, specifically, using electrostatic flocking method, silk short fibers are flocked on the surface of the substrate with adhesion to prepare a silver antler radiation refrigeration fluff structure. Silk is a natural fiber, its cross section is irregular shape, most of which is similar to triangular shape. Triangular cross section silk can refract and reflect a large amount of light, when the external light source is shot, the light path first reflects a large amount of light between the short fluff, blocking most of the incident light from transmitting to the surface of the substrate; when the light irradiates the surface of the triangular fiber, the light path is reflected and refracted in the fiber multiple times, which can further block the way of incident light transmitting to the surface of the substrate. At present, electrostatic flocking technology is very mature in industry, short fibers are vertically erected on the surface of various substrates, and are widely used in decorative materials and thermal insulation materials due to the flocking and embroidery feeling. The electrostatic flocking material is mainly short fluff, long fluff, chemical fiber and other materials, which are convenient for cutting, electrostatic treatment and other processes conducive to electrostatic flocking technology. Because the silk products on the market are mostly a plurality of silk fibers applied together, the very thin, long and soft silk after degumming will easily become a bundle and entangle together, and it is not possible to arrange it neatly and cut it to a controllable length, and after cutting, it is not neat short fibers, and it is easy to form nodules. The present application adopts the method of cutting the undegummed silk first and then degumming, although it is very thin and soft after degumming, it is very short and cannot entangle together, and is in the state of single short fiber, which is more convenient for subsequent screening and flocking, and breaks through the technical barrier that silk must be applied in long silk state. The silk short fibers obtained by shearing are electrostatically flocked on the surface of the substrate with adhesion to form a silver antler radiation refrigeration fluff structure.The silk used in the invention has unique optical properties. The inside of the silk is composed of densely arranged nanoscale fibrils, which gives the silk special Anderson optical positioning performance. This performance suppresses most of the transmitted light through the silk and enhances the reflectivity in the visible and near-infrared range, which enables the invention to achieve the function of a reflective layer alone (in patent application CN 114659290 A, the fiber array is composed of white nylon fibers, which mainly improves the reflectivity by using the white appearance of the nylon fibers. However, the other part of the reflectivity needs to be completed by the inorganic fillers in the bottom adhesive layer, which means that the top pile structure in this patent application cannot independently achieve the performance of reflecting a large amount of sunlight). The pile structure in the invention is obtained by soft silk flocking. The bottom is perpendicular to the adhesive layer, and the fibers at the top form a randomly stacked fiber layer due to their flexibility. There is an air layer between the fiber layer and the substrate, which is very conducive to the unique optical properties of silk, achieving enhanced reflection of sunlight and improving the ability of the pile structure to radiate mid-infrared waves, which helps the pile structure to achieve radiation cooling performance, thereby greatly reducing the requirements for the bottom adhesive layer and avoiding the problems of inorganic filler concentration and adhesive layer thickness affecting the preparation process and performance in patent application CN 114659290 A.

[0030] Advantages

[0031] (1) The silver ant-like radiation cooling pile structure of the invention uses triangular cross-section and electrostatic flocking technology to prepare a biomimetic structure that maximally restores the biological structure with radiation cooling performance in nature and achieves effective radiation cooling effect.

[0032] (2) The silver ant-like radiation cooling pile structure of the invention uses silk short fibers to construct a radiation cooling pile structure, breaking through the technical barrier that silk must be applied in filament form and providing a new idea and direction for the recycling of waste silk.

[0033] (3) The preparation method of the silver ant-like radiation cooling pile structure can use simple and mature electrostatic flocking process equipment to prepare pile structures on different substrate surfaces. In particular, on the surface of flexible substrates such as fabrics and wearable electronic devices, no reflective materials such as nano-particle fillers are needed. Only the special optical properties of mulberry silk are used to enhance the reflectivity of the structure to sunlight, without solid particle filling, ensuring the flexibility and mechanical properties of the substrate.

[0034] (4) The preparation method of the silver ant-like radiation cooling pile structure does not have special requirements for the surface of the adhesive fiber and the substrate, neither in thickness nor in type, ensuring the simplicity of the process. At the same time, when a transparent adhesive is selected, the color, appearance design, and other physical properties of the substrate itself can be ensured without being blocked.

[0035] (5) The silver ant prepared by the application can be prepared on the surface of fabric, wearable electronic devices and other personal temperature management materials, and can effectively radiate and cool, thereby obtaining good cooling effect, reducing the temperature of the sample and the surrounding temperature below the ambient temperature, and realizing the function of passive cooling without energy consumption. Meanwhile, since there is no special requirement for the adhesive layer, the moisture permeability and air permeability of the substrate are ensured to a certain extent, thereby overcoming the difficulty of applying the radiative cooling material in personal cooling management. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 The figure is a schematic diagram of the preparation process of the silver ant radiative cooling fluff structure of the application;

[0037] Figure 2 The figure is a schematic diagram of the silver ant radiative cooling fluff structure of Example 1 of the application;

[0038] Figure 3 The figure is a SEM image of the silver ant radiative cooling fluff structure of Example 1 of the application;

[0039] Figure 4 The figure is a radiative cooling effect diagram of the silicon rubber film prepared in Example 1 and Comparative Example 1 in the outdoor environment;

[0040] Figure 5 The figure is a radiative cooling effect diagram of the silicon rubber film prepared in Example 1 and Comparative Example 1 in the indoor environment without illumination;

[0041] In the figure, 1 is incident light, 2 is radiated medium and far infrared wave, 3 is reflected light, 4 is silk short fiber, and 5 is a surface layer with adhesion. DETAILED DESCRIPTION

[0042] The application will be further described in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the application and not to limit the scope of the application. In addition, it should be understood that those skilled in the art can make various modifications or changes to the application after reading the content of the application, and these equivalent forms also fall within the scope of the appended claims.

[0043] The source of the substance used in the application is as follows:

[0044] (1) Silicone rubber polydimethylsiloxane: from Dow Corning Company, with a trade name of Sylgard 184;

[0045] (2) Acrylic composite glue: from Yoshida Chemical Industry Co., Ltd., with a trade name of E0512;

[0046] (3) Water-based polyurethane glue: from Yoshida Chemical Industry Co., Ltd., with a trade name of F0400;

[0047] (4) Epoxy resin glue: from Yoshida Chemical Co., Ltd., trade name F0700.

[0048] In the present application, the prepared sample is subjected to performance test, specifically: the sample is covered on the surface of a thermocouple, the testing device is placed in a foam heat insulation box, and the box is sealed with an infrared transparent polyethylene film to reduce the influence of convection and heat conduction on the test results, and the ambient temperature is the temperature in the box without convection; the outdoor irradiation condition is specifically: the temperature is the ambient temperature in the box (related to the air temperature of the day, without a determined temperature), and the light intensity is 800 Wm -2 ; the indoor non-irradiation condition is specifically: the temperature is 27℃.

[0049] Example 1

[0050] A preparation method of a silver ant imitation radiation refrigeration fluff structure, as shown in Figure 1 , comprises the following steps:

[0051] (1) preparing a silk short fiber with a length of 3 mm and a diameter of 5-15 μm by physically shearing an un-degummed silk filament;

[0052] (2) boiling degumming the silk short fiber obtained in step (1) in a 0.5wt% sodium carbonate aqueous solution for 30 min, then rinsing with deionized water at a temperature of 60℃, repeating the boiling degumming and rinsing process for 3 times, and then drying at 60℃ to obtain a single silk short fiber with a triangular cross section;

[0053] (3) screening the single silk short fiber obtained in step (2) on the upper plate of an electrostatic flocking equipment, curing silicone polydimethylsiloxane at 80℃ for 15 min, placing it on the upper plate of the electrostatic flocking equipment, and electrostatic flocking by using a high-voltage electrostatic flocking equipment;

[0054] wherein the distance between the upper plate and the lower plate is 20 cm, the voltage of the electrostatic flocking is 30 kV, the time of the electrostatic flocking is 60 s, and the flocking density is 7.5 g / m 2 ;

[0055] (4) curing and drying the product after electrostatic flocking at 80℃ for 2 h, and then finishing by brushing to obtain a silver ant imitation radiation refrigeration fluff structure with a thickness of 1 mm.

[0056] As shown in Figures 2-3As shown, the silver ant-like radiation cooling fluff structure is composed of a plurality of arrayed silk short fibers 4, the bottom of each silk short fiber is vertically fixed on the surface of the substrate (i.e. the surface layer 5 with adhesion), the top is connected to each other to form a randomly stacked fiber layer, and an air layer is formed between the fiber layer and the substrate; the triangular cross-section silk can refract and reflect a large amount of light, when the external light source is incident, a large amount of reflection occurs between the short fluff in the transmission process, blocking most of the incident light 1 from transmitting to the surface of the substrate; when the light is incident on the surface of the triangular fiber, the light path is reflected and refracted multiple times inside the fiber, which can further block the way of the incident light 1 transmitting to the surface of the substrate; there is an air layer between the fiber layer and the substrate, which is very conducive to exerting the unique optical properties of silk, enhancing the reflected light 3 and improving the ability of the fluff structure to radiate the mid-infrared wave 2, which helps the fluff structure to realize the radiation cooling performance.

[0057] Under outdoor irradiation conditions, the micro-environmental temperature of the prepared silver ant-like radiation cooling fluff structure is averagely reduced by more than 6℃ than the surrounding temperature, as shown in Figure 4 Under indoor non-irradiation conditions, the micro-environmental temperature of the prepared silver ant-like radiation cooling fluff structure is averagely reduced by about 3℃ than the surrounding temperature, as shown in Figure 5 .

[0058] The silver ant-like radiation cooling fluff structure is applied to the cooling and refrigeration of wearable electronic products.

[0059] Comparative Example 1

[0060] A preparation method of a silicone rubber film, the silicone rubber polydimethylsiloxane is cured at 80℃ for 15min, after the flow is extended, it is directly heated and cured into a silicone rubber film without fluff structure.

[0061] Under outdoor irradiation conditions, the micro-environmental temperature of the prepared silicone rubber film is averagely reduced by 2℃ than the surrounding temperature, as shown in Figure 4 Under indoor non-irradiation conditions, the micro-environmental temperature of the prepared silicone rubber film is not significantly reduced than the surrounding temperature, as shown in Figure 5 .

[0062] Comparing Comparative Example 1 with Example 1, it can be found that the cooling and refrigeration effect of Example 1 is obviously better than that of Comparative Example 1, because Example 1 increases the fluff structure designed and prepared in the application, which reflects a large amount of sunlight under sunlight irradiation conditions, reduces the input of external energy, and at the same time, the existence of the fluff increases the emissivity of the substrate, increases the energy radiated outward and reduces the temperature; under indoor non-sunlight irradiation conditions, the existence of the fluff improves the radiation performance of the substrate to realize radiation cooling and reduce the temperature.

[0063] Example 2

[0064] A preparation method of a silver ant-like radiative cooling fluff structure, as shown in Figure 1 , comprising the following steps:

[0065] (1) preparing silk short fibers with a length of 4 mm and a diameter of 5-15 μm by physically shearing untreated silk filaments;

[0066] (2) boiling the silk short fibers obtained in step (1) in a 0.5 wt% sodium carbonate aqueous solution for 30 min, then rinsing with deionized water at a temperature of 60°C, repeating the boiling degumming and rinsing process 3 times, and then drying at 60°C to obtain single silk short fibers with a triangular cross section;

[0067] (3) placing a cotton cloth coated with acrylic composite glue on one side and solidified at 25°C for 30 min under the upper plate of an electrostatic flocking device, with the side coated with acrylic composite glue facing downward, and then electrostatic flocking is performed using a high-voltage electrostatic flocking device;

[0068] wherein the distance between the upper plate and the lower plate is 5 cm, the voltage for electrostatic flocking is 35 kV, the electrostatic flocking time is 30 s, and the flocking density is 5 g / m 2 ;

[0069] (4) solidifying and drying the product after electrostatic flocking at 100°C for 0.5 h, and then finishing with brushing to obtain a silver ant-like radiative cooling fluff structure with a thickness of 2 mm.

[0070] The silver ant-like radiative cooling fluff structure is composed of a plurality of arrayed silk short fibers, the bottom of each silk short fiber is fixed vertically on the surface of the substrate, the top is connected to each other to form a randomly stacked fiber layer, and an air layer is formed between the fiber layer and the substrate.

[0071] Under outdoor irradiation conditions, the microenvironment temperature of the prepared silver ant-like radiative cooling fluff structure is averagely reduced by 4°C compared with the surrounding environment temperature; under indoor non-irradiation conditions, the microenvironment temperature of the prepared silver ant-like radiative cooling fluff structure is averagely reduced by 2°C compared with the surrounding environment temperature.

[0072] The silver ant-like radiative cooling fluff structure is applied to cooling and refrigeration of clothing and textiles.

[0073] Example 3

[0074] A preparation method of a silver ant-like radiative cooling fluff structure, as shown in Figure 1 , comprising the following steps:

[0075] (1) preparing silk short fibers with a length of 5 mm and a diameter of 5-15 μm by physically shearing untreated silk filaments;

[0076] (2) The silk short fibers obtained in step (1) are immersed in a 0.5wt% sodium carbonate aqueous solution and boiled for degumming for 30 min, then rinsed with deionized water at a temperature of 60°C, and the boiling degumming and rinsing process is repeated for 3 times, and then dried at 60°C to obtain single silk short fibers with a triangular cross section;

[0077] (3) The single silk short fibers obtained in step (2) are screened on the lower plate of the electrostatic flocking equipment, a polyester fabric coated with water-based polyurethane glue on one side and cured at 100°C for 5 min is placed on the upper plate of the electrostatic flocking equipment with the side coated with water-based polyurethane glue facing down, and electrostatic flocking is carried out using a high-voltage electrostatic flocking equipment;

[0078] The distance between the upper plate and the lower plate is 30 cm, the voltage for electrostatic flocking is 5kV, the electrostatic flocking time is 10s, and the flocking density is 2.5g / m 2 ;

[0079] (4) The product after electrostatic flocking is cured and dried at 70°C for 1h, and then brushed and finished to obtain a silver ant-like radiative cooling flock structure with a thickness of 2mm.

[0080] The silver ant-like radiative cooling flock structure is composed of a plurality of arrayed silk short fibers, the bottom of each silk short fiber is vertically fixed on the surface of the substrate, the top is connected to each other to form a randomly stacked fiber layer, and an air layer is formed between the fiber layer and the substrate;

[0081] Under outdoor irradiation conditions, the microenvironment temperature of the prepared silver ant-like radiative cooling flock structure is averagely reduced by 2°C compared with the surrounding environment temperature; under indoor non-irradiation conditions, the microenvironment temperature of the prepared silver ant-like radiative cooling flock structure is averagely reduced by 3°C compared with the surrounding environment temperature.

[0082] The silver ant-like radiative cooling flock structure is applied to the cooling and refrigeration of an outdoor tent.

[0083] Example 4

[0084] A preparation method of a silver ant-like radiative cooling flock structure, as shown in Figure 1 , comprises the following steps:

[0085] (1) Un-degummed silk filaments are prepared into silk short fibers with a length of 6mm and a diameter of 5-15μm by physical shearing;

[0086] (2) The silk short fibers obtained in step (1) are immersed in a 0.5wt% sodium carbonate aqueous solution and boiled for degumming for 30 minutes, then washed with deionized water at a temperature of 60°C, and the process of boiling degumming and washing is repeated for 3 times, and then dried at 60°C to obtain single silk short fibers with a triangular cross section;

[0087] (3) The single silk short fibers obtained in step (2) are screened on the upper plate of the electrostatic flocking equipment, an iron sheet coated with epoxy resin glue and cured at 50°C for 25 minutes is placed on the upper plate of the electrostatic flocking equipment with the epoxy resin glue coated side facing down, and electrostatic flocking is performed using a high-voltage electrostatic flocking equipment;

[0088] The distance between the upper plate and the lower plate is 10cm, the voltage for electrostatic flocking is 15kV, the electrostatic flocking time is 90s, and the flocking density is 10g / m 2 ;

[0089] (4) The product after electrostatic flocking is cured and dried at 50°C for 3 hours, and then brushed and finished to obtain a silver ant-like radiative cooling flock structure with a thickness of 3mm.

[0090] The silver ant-like radiative cooling flock structure is composed of a plurality of arrayed silk short fibers, the bottom of each silk short fiber is fixed vertically on the surface of the substrate, the top is connected to each other to form a randomly stacked fiber layer, and an air layer is formed between the fiber layer and the substrate;

[0091] Under outdoor irradiation conditions, the micro-environmental temperature of the prepared silver ant-like radiative cooling flock structure is averagely reduced by 5°C compared with the surrounding temperature; under indoor non-irradiation conditions, the micro-environmental temperature of the prepared silver ant-like radiative cooling flock structure is averagely reduced by 5°C compared with the surrounding temperature.

[0092] The silver ant-like radiative cooling flock structure is applied to the cooling and refrigeration of a cooler.

[0093] Example 5

[0094] A preparation method of a silver ant-like radiative cooling flock structure, as shown in Figure 1 , comprises the following steps:

[0095] (1) Un-degummed silk filaments are prepared into silk short fibers with a length of 7mm and a diameter of 5-15μm by physical shearing;

[0096] (2) The silk short fibers obtained in step (1) are immersed in a 0.5wt% sodium carbonate aqueous solution and boiled for degumming for 30 minutes, then washed with deionized water at a temperature of 60°C, and the process of boiling degumming and washing is repeated for 3 times, and then dried at 60°C to obtain single silk short fibers with a triangular cross section;

[0097] (3) The single silk short fiber obtained in step (2) is placed on the upper plate of the electrostatic flocking equipment, and a cotton cloth coated with silicone rubber and solidified at 75°C for 20 min is placed on the upper plate of the electrostatic flocking equipment with the coated side facing down, and electrostatic flocking is performed using a high-voltage electrostatic flocking equipment;

[0098] wherein the distance between the upper plate and the lower plate is 25 cm, the voltage for electrostatic flocking is 20 kV, the electrostatic flocking time is 120 s, and the flocking density is 12.5 g / m 2 ;

[0099] (4) The product after electrostatic flocking is solidified and dried at 40°C for 4 h, and then is subjected to a brushing finishing to obtain a silver ant imitation radiation cooling wool structure with a thickness of 3 mm.

[0100] The silver ant imitation radiation cooling wool structure is composed of a plurality of arrayed silk short fibers, the bottom of each silk short fiber is vertically fixed on the surface of a substrate, the top of each silk short fiber is connected to each other to form a randomly stacked fiber layer, and an air layer is formed between the fiber layer and the substrate.

[0101] Under outdoor irradiation conditions, the microenvironment temperature of the prepared silver ant imitation radiation cooling wool structure is averagely reduced by 7°C compared to the surrounding temperature; under indoor non-irradiation conditions, the microenvironment temperature of the prepared silver ant imitation radiation cooling wool structure is averagely reduced by 4°C compared to the surrounding temperature.

[0102] The silver ant imitation radiation cooling wool structure is applied to cooling and refrigeration of clothing and textiles.

Claims

1. A silver ant-like radiative cooling fluff structure applied to the cooling and refrigeration of clothing textiles and wearable electronic products, characterized in that: The silver ant-like radiation refrigeration fluff structure is composed of a plurality of arrayed short silk fibers with triangular cross sections, the bottom of each short silk fiber with triangular cross section is fixed vertically on the surface of a substrate, and the top is connected to each other to form a fiber layer, and an air layer is formed between the fiber layer and the substrate; ​ The thickness of the silver ant-like radiation refrigeration fluff structure is 1-3 mm. The preparation method of the single short silk fiber with triangular cross section comprises the following steps: firstly, preparing short silk fibers with desired length from long silk filaments without degumming treatment by physical shearing, and then degumming the short silk fibers to obtain single short silk fibers with triangular cross section. The silver ant-like radiation refrigeration fluff structure is prepared by electrostatic flocking of a plurality of short silk fibers with triangular cross section on the surface of a substrate with adhesion, and the electrostatic flocking time is 10-120 s.

2. The method for preparing a silver ant-inspired radiation-cooled villous structure as described in claim 1, characterized in that, The method comprises the following steps: (1) preparing short silk fibers with desired length from long silk filaments without degumming treatment by physical shearing; (2) degumming the short silk fibers obtained in step (1) to obtain single short silk fibers with triangular cross section; (3) screening the single short silk fibers with triangular cross section obtained in step (2) on the lower plate of an electrostatic flocking device, placing the surface layer with adhesion on the upper plate of the electrostatic flocking device with the adhesion surface facing downward, and electrostatic flocking by using a high-voltage electrostatic flocking device; (4) solidifying and drying the product after electrostatic flocking, and then finishing the product by brushing to obtain the silver ant-like radiation refrigeration fluff structure.

3. The preparation method of the silver-ant simulation radiative cooling fluff structure according to claim 2, characterized in that, In step (1), the length of the short silk fibers is 2-7 mm, and the diameter is 5-15 µm.

4. The preparation method of the silver-ant simulation radiative cooling fluff structure according to claim 2, characterized in that, In step (2), the degumming process comprises the following steps: boiling the short silk fibers in a 0.5wt% sodium carbonate aqueous solution for 30 min, rinsing with deionized water at 60 ℃, repeating the boiling degumming and rinsing process for 3 times, and then drying at 60 ℃.

5. The method for preparing a simulated silver ant radiation-cooled villous structure according to claim 2, characterized in that, In step (3), the surface layer with adhesion is a semi-cured fabric surface, metal surface, plastic surface or film-forming surface coated with an adhesive.

6. The method of claim 5, wherein the silver ant structure is prepared by the steps of: providing a silver ant structure; and coating the silver ant structure with a radiation-reflecting material. The adhesive is one or more of acrylic composite glue, water-based polyurethane glue, epoxy resin glue and silicone rubber; The semi-cured method is to cure at a temperature of 25-100 ℃ for 5-30 min.

7. The method of claim 2, wherein the silver ant structure is prepared by the following steps: (1) preparing a silver ant structure by the method of claim 1; (2) coating the silver ant structure with a radiation-reflecting material; and (3) removing the radiation-reflecting material from the silver ant structure. In step (3), the distance between the upper plate and the lower plate is 5-30 cm, and the electrostatic flocking voltage is 5-35 kV.

8. The preparation method of the silver-ant simulation radiative cooling fluff structure according to claim 2, characterized in that, In step (4), the drying temperature is 40-100 ℃, and the drying time is 0.5-4 h.

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