Masterbatch, radiative cooling fiber, radiative cooling multilayer fabric and its applications

Abstract

The present invention provides a masterbatch containing a radiative cooling powder mixture, a radiative cooling fiber produced using the masterbatch, and a radiative cooling multi-layer fabric produced using the radiative cooling fiber. [Solution] A masterbatch is disclosed that consists of 10wt%-30wt% of a radiative cooling powder mixture and 70wt%-90wt% of a polymer substrate. The masterbatch of the present invention can be used to manufacture fiber fabrics with radiative cooling functions. The present invention disperses the radiative cooling powder mixture and the heat-absorbing functional masterbatch in a thermal emitting layer and a thermally conductive layer, respectively. The thermal emitting layer plays the role of radiative cooling, while the thermally conductive layer plays the role of heat absorption and transfer, allowing the thermally conductive layer to have a much higher temperature, ensuring high-power radiation from the radiative cooling powder and achieving lower radiative cooling temperatures.

Description

[Technical Field]

[0001] The present invention relates to the technical field of radiative cooling, specifically to masterbatches, radiative cooling fibers, radiative cooling multilayer fabrics and their applications. [Background technology]

[0002] Radiative cooling achieves cooling by radiating heat from an object to a cooling source in the form of electromagnetic waves. Its main advantage is that it does not require the input of other forms of energy. At normal ambient temperatures, blackbody radiators emit infrared radiation in the 8-13 μm range. To achieve cooling, some of this energy can be radiated to the cooling source. For surface objects, outer space can be considered a natural transparent window in the 8-13 μm range. Radiative cooling utilizes this atmospheric window to radiate heat into outer space, saving energy and pollution.

[0003] Adding functional components with radiative cooling capabilities to composite fibers to impart radiative cooling effects has become an important application direction for radiative cooling. Most polymer fibers themselves have good thermal conductivity and lack significant absorption of far-infrared radiation in the 4-14 μm range. Human skin is also an infrared transmitter with an emissivity of 0.98. The thermal radiation emitted by the human body at rest is primarily mid-infrared radiation in the 7-14 μm range. Therefore, adding functional particles capable of emitting radiation in the 8-13 μm range through the atmospheric window can enable composite fibers to emit infrared radiation across almost the entire wavelength range, achieving highly efficient cooling. For example, Chinese Patent CN111455483A discloses a method for producing radiative cooling fibers and fabrics using the same. The method involves proportionally blending inorganic microparticles with a polymer matrix to produce a composite masterbatch, which is then extruded to produce radiative cooling fibers. The radiative cooling fibers are then knitted and / or woven into radiative cooling fabrics. In the radiative cooling fiber of this patent application, the inorganic micro-nanoparticles are uniformly dispersed, and the fibers in the produced fabric are also uniform. Therefore, the inorganic micro-nanoparticles inside the fabric block infrared radiation emitted into the atmospheric window, and if they do not have the function of directional radiation, the radiative cooling effect of the fabric will be reduced. For example, Chinese Patent No. CN 118007296A discloses a method for producing radiative cooling fabric materials and products thereof, which first uses electrospinning to produce nano-cooling fibers, and then sprays nano-radiative particles on the surface of the nano-cooling fibers. The nano-cooling fibers have the ability to scatter sunlight and achieve a synergistic effect with the nano-radiative particles sprayed on the surface. However, because the nano-radiative particles are sprayed on the surface of the nanofibers, the sprayed nano-radiative particles fall off, which seriously affects the feel and range of use of the fabric and prevents the fabric from achieving long-term radiative cooling effects.

[0004] Common sense tells us that no matter what temperature an object is, the higher its temperature, the higher the thermal radiation power it emits. According to the Stefan-Boltzmann law, the emitted power is proportional to the fourth power of the emitter's absolute temperature, so an increase in the emitter temperature can significantly increase the thermal radiation power. However, when it comes to radiative cooling fabrics, whether they are wearable clothing or home textiles, in an indoor environment, there is air between the heat source (the human body) and the fabric. After the radiation cools to a certain temperature, the air between the heat source and the fabric acts as an insulator, preventing sufficient heat accumulation in the fabric, limiting the temperature reduction achieved by radiative cooling fabrics. Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional radiative cooling fibers lack radiation directionality, and there are situations where heat is not maintained between the manufactured radiative cooling fabric and the heat source. These two problems result in a limited degree of temperature reduction in radiative cooling textile products. To solve these problems, the present invention proposes a masterbatch containing a radiative cooling powder mixture, as well as radiative cooling fibers manufactured using this masterbatch and radiative cooling multi-layer fabrics manufactured using the radiative cooling fibers.

[0006] The first aspect of the present invention provides a masterbatch, which comprises 10 wt% to 30 wt% of a radiative cooling powder mixture and 70 wt% to 90 wt% of a polymer substrate, and is produced using a melt granulation method, and the particle size of the masterbatch is 0.5 to 4 mm.

[0007] In the masterbatch of the present invention, the radiative cooling powder mixture is composed of the following components in parts by weight: 10-20 parts of SiO2, 9-22 parts of SiC, 2-10 parts of TiO2, 1-15 parts of ZnO, 2-10 parts of ZnS, 2-10 parts of BaSO4, 2-10 parts of Al2O3, 0-10 parts of boron nitride, 0-5 parts of graphene, 0-10 parts of antibacterial material, 0-20 parts of polyethylene, 0-5 parts of polycarbonate, and 0-10 parts of polyethylene oxide.

[0008] Furthermore, when the weight ratio of SiO2 to SiC is 1:(0.9-1.1), the combined radiation ranges of SiO2 and SiC within this ratio range exhibit stable, high radiation characteristics in the wavelength range of 4-14 μm. When the weight ratio of TiO2 to ZnO is 1:(0.5-1.5), the combination of TiO2 and ZnO can efficiently emit wavelengths above 13 μm, achieving full radiation in the far-infrared wavelength range. When the weight ratio of boron nitride, graphene, or Al2O3 to BaSO4 is 1:(0.7-1.3), within this ratio range, these materials all have high thermal conductivity, allowing the fiber to continuously absorb heat from the heat source (human body) and achieve a sustained cooling effect.

[0009] In the masterbatch of the present invention, the polymer substrate is one of PE, PP, PA6, PA66 or PET, and the selected polymer substrate itself has excellent thermal conductivity, can quickly conduct heat to the radiative cooling powder, and does not have significant absorption performance for infrared rays with a wavelength of 4 to 14 μm, so it does not block the radiation of the radiative cooling powder for infrared rays with a wavelength of 4 to 14 μm.

[0010] The second aspect of the present invention provides a fiber with radiative cooling function, which comprises 75wt%-95wt% of fiber raw material and 5wt%-25wt% of the above masterbatch, where the material of the fiber raw material is selected from one of PE, PP, PA, PET or PMMA, and is produced by melt spinning or solution spinning technology.

[0011] The third aspect of the present invention provides a multilayer fabric with radiative cooling function. Because radiative cooling must be performed directly on the atmospheric window, the fiber of the present invention must be placed on the outermost layer when applied to the radiative cooling multilayer fabric. The radiative cooling multilayer fabric of the present invention comprises, from top to bottom, a thermally emitting layer, a thermally conductive layer, and a lining layer. The thermally emitting layer is woven using the radiative cooling fiber of the present invention, and the thermally conductive layer contains 5 wt% to 20 wt% of a heat-absorbing masterbatch. By using appropriate weaving techniques, the radiative layer can be positioned on the outermost layer, radiating infrared rays directly to the atmospheric window. The middle layer is a thermally conductive layer that absorbs heat toward the heat source and plays the roles of heat absorption, heat storage, and heat conduction. The lining layer is made of woven PE, PET, or nylon fibers.

[0012] Specifically, the endothermic functional masterbatch is composed of the following components in parts by weight: 2 to 20 parts of graphene, 5 to 20 parts of aluminum powder, 1 to 5 parts of copper powder, 2 to 10 parts of carbon nanotubes, and 2 to 5 parts of polyimide powder, and the endothermic functional masterbatch is produced using a melt granulation method.

[0013] The multi-layer fabric, which contains SiC, Al2O3, graphene, aluminum powder, copper powder, and polyimide powder, has radiative cooling properties and can also reflect and block high-energy infrared rays with wavelengths of 780 to 2500 nm.

[0014] The present invention disperses a mixture of radiative cooling powder and an endothermic functional masterbatch in the heat radiation layer and the heat conduction layer, respectively, so that the part containing the radiative cooling powder plays the role of radiative cooling, and the part containing the endothermic functional masterbatch plays the role of absorbing heat from the human body or the room, allowing the heat conduction layer to have a much higher temperature and ensuring the high-power radiation of the radiative cooling powder, so that each function can be better performed without being affected and a synergistic effect can be achieved, which enhances the radiative cooling ability of the multi-layer fabric and achieves a lower radiative cooling temperature. The multi-layer fabric of the present invention can reflect, block or emit infrared rays of all wavelengths, and after the finished product is manufactured, it can significantly cool the environment, or the fabric itself can provide a lasting cooling sensation.

[0015] The multilayer fabric of the present invention functions as a radiative cooling device when the temperature is high during the day, and has a heat-retaining function when the temperature is low at night due to the heat-absorbing and heat-storing functional particles added thereto. The multilayer fabric of the present invention can be used as a surface layer for household and outdoor products such as clothing, home textile products, curtains, and tents. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a structural schematic diagram of the radiative cooling multilayer fabric of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] In order to make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in combination with the drawings in the embodiments of the present invention.

[0018] 1. Masterbatch manufacturing Table 1 shows the component ratios of the radiative cooling powder mixture for radiative cooling masterbatches 1 to 6. Table 2 shows the specific materials and mass ratios of the polymer substrates for radiative cooling masterbatches 1 to 6. After uniformly mixing the components in Table 1, they were mixed with the polymer substrate according to the mass ratios in Table 2, melted, and granulated to prepare radiative cooling masterbatches 1 to 6. Table 3 shows the component ratios of endothermic functional masterbatches 1' to 6'. After uniformly mixing the components in Table 3, they were mixed with the same polymer substrates in Table 2 in the same ratios, melted, and granulated to obtain endothermic functional masterbatches 1' to 6'. The dimensions of radiative cooling masterbatches 1 to 6 and endothermic functional masterbatches 1' to 6' were both 2.5 x 4 mm.

[0019] [Table 1]

[0020] [Table 2]

[0021] [Table 3]

[0022] 2. Textile manufacturing The fiber raw materials are respectively fed into the screw of the spinning machine in a certain proportion as radiation cooling masterbatches 1-6 and endothermic functional masterbatches 1'-6' by a metering pump and melted. The temperatures in zones 1 to 5 are controlled at 190-280°C, 200-285°C, 220-290°C, 220-290°C, and 220-285°C, respectively. The melt is ejected through the spinneret, side-air dried, oiled, drafted, and packaged to obtain radiation cooling filaments or high thermal conductivity filaments, with filament specifications of 50-300D / 48-228f.

[0023] 3. Radiation cooling fabric manufacturing As shown in Figure 1, the radiative cooling multilayer fabrics of Examples 1 to 6 were woven from radiative cooling fibers and high thermal conductivity fibers. The fabric structure of the fabric is a woven fabric consisting of a thermal radiation layer 1, a thermal conductivity layer 2, and a backing layer 3. The thermal radiation layer 1 is woven with radiative cooling filaments, the thermal conductivity layer 2 is woven with high thermal conductivity filaments, and the backing layer 3 is a fiber cloth woven with PE, PET, or nylon fibers. The radiative cooling multilayer fabric can be formed by a special weaving method or by combining three types of fabrics. The type of fiber substrate and the fiber fineness of each layer can be the same or different. The gram weight fraction of each layer in the radiative cooling multilayer fabric is 40% to 70% for the thermal radiation layer 1, 20% to 50% for the thermal conductivity layer 2, and 10% to 30% for the backing layer 3. Specific parameters for each example are as follows:

[0024] Example 1 The radiative cooling multi-layer fabric has a fiber fineness of 60D in each layer. The thermal radiation layer 1 is composed of 75 wt% polyethylene particles and 25 wt% radiative cooling masterbatch 1, and the thermal conduction layer 2 is composed of 85 wt% polyethylene particles and 15 wt% endothermic functional masterbatch 1'.

[0025] Example 2 This is a radiative cooling multi-layer fabric, and the fiber fineness of each layer is 7D. The thermal radiation layer 1 is composed of 80 wt% PA6 particles and 20 wt% radiative cooling masterbatch 2, and the thermal conduction layer 2 is composed of 85 wt% PA6 particles and 15 wt% endothermic functional masterbatch 2'.

[0026] Example 3 The radiative cooling multi-layer fabric has a fiber fineness of 60D in the heat-emitting layer 1, which is composed of 85 wt% polyethylene particles and 15 wt% radiative cooling masterbatch 3, and a fiber fineness of 75D in the heat-conducting layer 2, which is composed of 90 wt% PA6 particles and 10 wt% endothermic functional masterbatch 3'.

[0027] Example 4 The radiative cooling multi-layer fabric has a fiber fineness of 150D in the thermal radiation layer 1, which is composed of 90 wt% PET particles and 10 wt% radiative cooling masterbatch 6, and a fiber fineness of 60D in the thermal conduction layer 2, which is composed of 87 wt% PA66 particles and 13 wt% endothermic functional masterbatch 4'.

[0028] Example 5 The radiative cooling multi-layer fabric has a fiber fineness of 150D in the thermal radiation layer 1, which is composed of 90wt% PET particles and 10wt% radiative cooling masterbatch 6, and a fiber fineness of 75D in the thermal conduction layer 2, which is composed of 80wt% PA6 particles and 20wt% heat-absorbing functional masterbatch 5'.

[0029] Example 6 The radiative cooling multi-layer fabric has a fiber fineness of 150D in the thermal radiation layer 1, which is composed of 95 wt% PET particles and 5 wt% radiative cooling masterbatch 6, and a fiber fineness of 150D in the thermal conduction layer 2, which is composed of 95 wt% PET particles and 5 wt% heat-absorbing functional masterbatch 6'.

[0030] The multilayer fabrics of Comparative Examples 1 to 6 were produced by replacing the heat conduction layer 2 in the radiative cooling multilayer fabrics of Examples 1 to 6 with a lining layer 3, respectively.

[0031] Blank Examples 1 to 6 are fabrics of the same specifications obtained after removing the radiative cooling masterbatch and endothermic functional masterbatch from the radiative cooling multilayer fabrics of Examples 1 to 6, respectively.

[0032] 4. Testing and evaluation of results 1. Testing and evaluation of radiative cooling effects a. Production of radiative cooling fabric: The thermal radiation layer 1, thermal conduction layer 2 and lining layer 3 were mixed at gram weight ratios of 60%, 20% and 20%, respectively, to produce curtains measuring 3 meters long, 1.8 meters wide and 1.8 meters high using the fabrics of Examples 1-6, Comparative Examples 1-6 and Blank Examples 1-6.

[0033] b. Preparation of radiative cooling equipment. Three rooms with the same layout and an indoor area of ​​15 square meters were selected, with windows facing south. Each room had only one type of window, with a window glass size of 1.2 meters high and 1.5 meters wide, and a light transmittance of more than 92%.

[0034] c. Comparative test of radiative cooling. The test took place in Yantai, a city in northern China, in the summer of August, with an outdoor temperature of 32-35°C and a humidity of 30-50%. Before the test, the glass windows were closed and uncovered with curtains, allowing the sun to shine directly into the room. During the test, the curtains completely covered the windows, and a temperature sensor was placed 1 meter away from the curtains and 1.5 meters high. After the door was closed and sealed, the indoor and outdoor temperatures were recorded simultaneously every half hour. The test time was from 9:00 a.m. to 12:00 p.m., the test cycle was 3 hours, and the test was conducted in groups of three for 6 consecutive days. The results are shown in Table 4.

[0035] The data in Table 4 reveal that the curtains made from the radiative refrigerant fibers of Examples 1 to 6 have a higher radiative cooling effect than the multilayer fibers without a thermally conductive layer 2 of Comparative Examples 1 to 6, because the heat-absorbing functional masterbatch in the thermally conductive layer 2 absorbs heat more quickly and transfers it to the radiative refrigerant powder in the thermal radiative layer 1, and the radiative refrigerant powder has high radiative power even at slightly lower temperatures, thereby further reducing the temperature. On the other hand, the pure polymer fibers of Examples 1 to 6 do not have radiative cooling capabilities, can only reflect sunlight to a limited extent, and cannot radiate infrared rays with wavelengths of 8 to 13 μm to the atmosphere. As a result, the indoor temperature rises as the outdoor temperature rises, and the cooling effect is very limited.

[0036] [Table 4]

[0037] 2. Thermal performance test Taking into account the needs of radiative cooling fabrics in different applications, the fabric's solar reflectance ratio and atmospheric window emissivity performance tests can better evaluate the fabric's radiative cooling performance, while the cool-to-the-touch test can be used for radiative cooling applications using the human body as a heat source, such as clothing and home textiles, to achieve cooling through radiative cooling, while also achieving a cooling effect through high thermal conductivity. Table 5 shows the thermal performance test data for the cool-to-the-touch, heat-shielding rate, solar reflectance ratio, and emissivity of the fabrics of Examples 1-6, Comparative Examples 1-6, and Blank Examples 1-6.

[0038] [Table 5]

[0039] The above description of the disclosed embodiments will enable those skilled in the art to make or use the present invention. Various modifications of these embodiments will be apparent to those skilled in the art, as the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A masterbatch comprising: It consists of 10 wt% to 30 wt% of a radiative cooling powder mixture and 70 wt% to 90 wt% of a polymer matrix; The radiative cooling powder mixture contains the following components in parts by weight: SiO ２ 10-20 parts, SiC 9-22 parts, TiO ２ 2 to 10 parts, ZnO 1 to 15 parts, ZnS 2 to 10 parts, BaSO ４ 2 to 10 parts Al ２ O ３ 2-10 parts of polyethylene oxide, 0-20 parts of polyethylene terephthalate, 0-5 parts of polycarbonate, 0-5 parts of polyethylene oxide, 0-10 parts of boron nitride, 0-10 parts of graphene, 0-5 parts of antibacterial material, 0-20 parts of polyethylene terephthalate, 0-5 parts of polycarbonate, and 0-10 parts of polyethylene oxide, The masterbatch is characterized in that the polymer substrate is one of PE, PP, PA6, PA66 or PET.

2. 2. The masterbatch according to claim 1, wherein the particle size of the masterbatch is 0.5 to 4 mm.

3. SiO ２ and SiC in a weight ratio of 1: (0.9 to 1.1), and TiO ２ and ZnO in a weight ratio of 1: (0.5 to 1.5), and boron nitride and graphene or Al ２ O ３ and BaSO ４ The masterbatch according to claim 2, characterized in that the weight ratio of

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