Double-layer quick-drying moisture-permeable high-emission refrigeration film as well as preparation method and application thereof

Abstract

The invention provides a double-layer quick-drying moisture-permeable high-emission refrigeration film as well as a preparation method and application thereof. The double-layer quick-drying moisture-permeable high-emission refrigeration film comprises a hydrophilic layer and a hydrophobic layer, wherein the hydrophilic layer comprises titanium carbide and polyurethane, the hydrophobic layer comprises polyvinylidene fluoride and an adhesive, and the double-layer quick-drying moisture-permeable high-emission refrigeration film further comprises an alkaline substance. The double-layer quick-drying moisture-permeable high-emission refrigeration film has the characteristics of better refrigeration performance, higher moisture permeability and better wearable performance, including but not limited to high moisture permeability and high air permeability.

Description

Technical Field

[0001] The present invention belongs to the technical field of double-layer quick-drying, moisture-permeable and highly emissive refrigeration films, and in particular relates to a quick-drying, moisture-permeable refrigeration film with mid-infrared high emissivity characteristics, and a preparation method and application thereof. Background Art

[0002] Radiative cooling technology has shown great promise in reducing the cost of space cooling in various cooling applications. In contrast to active cooling that requires electricity to drive the refrigeration cycle, radiative cooling uses a transparent window in the atmosphere to emit thermal radiation directly to outer space without consuming any energy. Cooling technology is of great significance to human activities in order to maintain appropriate temperatures in extreme environments. Currently, electric systems such as air conditioning are widely used as a preferred and important cooling technology. However, it consumes a lot of energy to cool the space, which forces us to explore new cooling technologies with lower or zero energy consumption in the context of the increasingly serious energy crisis. Due to its characteristic of no energy consumption, it will be a very promising strategy for saving energy.

[0003] In recent years, radiative cooling clothing has gradually emerged in people's field of vision and has quickly attracted great interest because they are light and provide good thermal comfort to the body without any energy input. Considering the cost and practical situation, radiative cooling clothing has been considered an attractive strategy, but its function is not perfect enough. Based on radiative cooling technology, the atmosphere has a high transmittance or emissivity in the range of 8-13 microns. Radiative cooling clothing can cool objects to low temperatures by strongly emitting thermal radiation in the range of 8-13 microns. Although there have been some studies on radiative cooling clothing, most of the red radiative cooling clothing still has a serious problem in achieving fast drying and moisture perspiration, that is, water molecules are bidirectionally transported in the fabric. Unfortunately, the manufacturing technology of these radiative cooling materials is complicated and cannot be fast drying and moisture perspiration, which limits the practical application of these radiative cooling clothing. Designing a radiative cooling clothing with simple manufacturing process and directional fast drying and sweat perspiration performance is very important in the field of functional clothing.

[0004] Moisture wicking technology has attracted increasing attention due to its ability to provide a drier and cooler microclimate for personal thermal comfort under extreme environmental conditions, such as those faced by athletes, soldiers, or industrial workers. Most moisture wicking fabrics are composed of synthetics such as polyester and nylon, which, unlike cotton, can quickly pull moisture away from the skin and absorb little moisture when humans sweat. However, due to the limited moisture transport capacity of such fabrics, the evaporation rate of moisture is relatively slow, and the moisture absorption process of such fabrics is bidirectional; that is, it can be triggered from the skin to the environment or in the opposite direction, which will limit its practical application in high-humidity environmental conditions. To address these limitations, it is very important to develop smart quick-drying, moisture-permeable radiant cooling fabrics. Summary of the invention

[0005] In order to solve the above problems, the purpose of the present invention is to provide a double-layer quick-drying, moisture-permeable and highly emissive refrigeration film and a preparation method and application thereof. The double-layer quick-drying, moisture-permeable and highly emissive refrigeration film has better refrigeration performance, faster moisture permeability and better wearability, including but not limited to the characteristics of high moisture permeability.

[0006] In order to achieve the above-mentioned purpose, the present invention provides a double-layer quick-drying, moisture-permeable and highly emissive refrigeration film, which includes a hydrophilic layer and a hydrophobic layer; wherein the hydrophilic layer contains titanium carbide and polyurethane, and the hydrophobic layer contains polyvinylidene fluoride and an adhesive (preferably polyurethane), and the composition of the double-layer quick-drying, moisture-permeable and highly emissive refrigeration film also includes alkaline substances.

[0007] According to a specific embodiment of the present invention, preferably, calculated by weight, the composition of the double-layer quick-drying, moisture-permeable and highly emissive refrigeration film comprises less than 10 parts of polyvinylidene fluoride, less than 30 parts of titanium carbide, 10-30 parts of polyurethane, and less than 10 parts of alkaline substances.

[0008] According to a specific embodiment of the present invention, preferably, calculated by weight, the composition of the double-layer quick-drying, moisture-permeable and highly emissive refrigeration film comprises 10 parts of polyvinylidene fluoride, 10-30 parts of titanium carbide (more preferably 10-20 parts), 10-20 parts of polyurethane, and less than 10 parts of alkaline substances.

[0009] According to a specific embodiment of the present invention, preferably, in the hydrophilic layer, the weight ratio of the titanium carbide to the polyurethane is 0.1-1:1, more preferably 1:1.

[0010] According to a specific embodiment of the present invention, preferably, in the hydrophobic layer, the weight ratio of the polyvinylidene fluoride to the polyurethane is 0.1-1:1, more preferably 1:1.

[0011] According to a specific embodiment of the present invention, preferably, the alkaline substance comprises sodium hydroxide.

[0012] According to a specific embodiment of the present invention, preferably, the composition of the double-layer quick-drying, moisture-permeable and highly emissive refrigeration film further comprises less than 5 parts of sodium hydroxide.

[0013] According to a specific embodiment of the present invention, preferably, the particle size of the titanium carbide is ≤2 μm, more preferably 0.5-1 μm.

[0014] According to a specific embodiment of the present invention, preferably, the thickness of the double-layer quick-drying, moisture-permeable and highly emissive refrigeration film is 0.01-0.015 mm.

[0015] According to a specific embodiment of the present invention, preferably, the moisture permeability of the double-layer quick-drying, moisture-permeable, high-emissivity refrigeration film is greater than 12000 g·m 2 / 24h.

[0016] According to a specific embodiment of the present invention, preferably, the refrigeration temperature of the double-layer quick-drying, moisture-permeable and highly emissive refrigeration film is greater than 2°C.

[0017] The present invention also provides a method for preparing the above-mentioned double-layer quick-drying, moisture-permeable, and highly emissive refrigeration film, which comprises the following steps: (1) mixing and dispersing polyvinylidene fluoride and an adhesive in a solvent to obtain a polymer solution; mixing and dispersing titanium carbide and polyurethane in a solvent to obtain a functional material solution; (2) making the above-mentioned polymer solution into a moisture-permeable film, and then forming a highly emissive, moisture-permeable, and refrigeration film on the surface of the moisture-permeable film with the above-mentioned functional material solution to obtain a double-layer film; (3) subjecting the above-mentioned double-layer film to an alkali treatment, and vacuum drying to obtain the double-layer quick-drying, moisture-permeable, and highly emissive refrigeration film.

[0018] According to a specific embodiment of the present invention, preferably, in step (1), the temperature of mixing and dispersing is 50-60°C, more preferably 60°C.

[0019] According to a specific embodiment of the present invention, preferably, the solvent of the polymer solution and the functional material solution includes one or a combination of two or more of dimethylformamide, tetrahydrofuran, and acetone, and dimethylformamide is more preferred. The selected solvent can fully dissolve the polymer powder, and the solution does not contain highly toxic chemicals, so that the prepared product has low toxicity residue and low environmental pollution.

[0020] According to a specific embodiment of the present invention, preferably, the amount of dimethylformamide used is 80 parts or less.

[0021] According to a specific embodiment of the present invention, preferably, the moisture permeable film and the high-emission moisture permeable refrigeration film are formed by electrospinning technology.

[0022] According to a specific embodiment of the present invention, preferably, the voltage of electrospinning is 20-25 KV, the syringe advancement rate is 0.3-0.5 mL / h, and the collection distance is 12-15 cm.

[0023] According to a specific embodiment of the present invention, preferably, the voltage of electrospinning is 25 KV, the syringe advancement rate is 0.5 mL / h, and the collection distance is 15 cm.

[0024] According to a specific embodiment of the present invention, preferably, in step (3), the alkali treatment is performed by soaking in a sodium hydroxide solution for 5-10 minutes.

[0025] According to a specific embodiment of the present invention, the above preparation method comprises the following specific steps:

[0026] (1) dissolving 10-20 parts by weight of polyvinylidene fluoride and polyurethane powder in 80 parts by weight of dimethylformamide, stirring to obtain a polymer electrospinning solution (i.e., the aforementioned polymer solution); dispersing 10-20 parts by weight of titanium carbide functional material in 80 parts by weight of dimethylformamide, ultrasonically stirring for half an hour, adding 20 parts by weight of polyurethane powder, ultrasonically stirring and obtaining a functional material-doped polymer electrospinning original solution (i.e., the aforementioned functional material solution);

[0027] (2) forming a film from the polymer electrospinning solution using an electrospinning technique to obtain a moisture permeable film;

[0028] (3) forming a film of the polymer electrospinning solution doped with the functional material on the moisture permeable film obtained in step (2) by using an electrospinning technique to obtain a moisture permeable high-emissivity refrigeration film, thereby forming a double-layer film;

[0029] (4) Soaking the double-layer film in a solution of sodium hydroxide of less than 5 parts by weight for less than 10 minutes, and drying in a vacuum oven to obtain the double-layer quick-drying, moisture-permeable, high-emissivity refrigeration film. The alkali treatment process changes the hydrophilicity of the functional material, so that the electrospun film doped with the functional material has more hydrophilic groups, thereby accelerating the transmission of water molecules.

[0030] The present invention also provides the application of the above-mentioned double-layer quick-drying, moisture-permeable and highly emissive refrigeration film in the fields of refrigeration clothing, moisture-permeable clothing, building structure cloth membranes, and smart wearables.

[0031] The double-layer electrospun film with hydrophilic difference of the present invention has high mid-infrared emission characteristics, and the doped functional material has fast-drying thermal conductivity and its layered structure provides a transmission channel for water molecules, thereby achieving a fast-drying, moisture-permeable, high-emission refrigeration effect; at the same time, the double-layer fast-drying, moisture-permeable, high-emission refrigeration film of the present invention has more supramolecular bonds between the polymer powder and the functional material. Since a large number of hydrophilic groups exist on the surface of the functional material, it is tightly combined with the polyurethane, so there will be no phenomenon of functional material falling off in later use, thereby avoiding the problem of reduced thermal insulation performance of the fast-drying, moisture-permeable, refrigeration film in later use. In summary, the double-layer fast-drying, moisture-permeable, high-emission refrigeration film of the present invention has the characteristics of good refrigeration performance, faster moisture permeability and better wearable performance. It is expected to become a promising textile material for optimizing mid-infrared emissivity, and is used in refrigeration clothing, moisture-permeable clothing, architectural structure cloth membranes and smart wearable fields, and the preparation process is streamlined, the process is simple, and it is easy to realize industrialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the process flow for preparing a double-layer quick-drying, moisture-permeable, and highly emissive refrigeration film;

[0033] Figure 2 Thermal imager pictures for cooling performance;

[0034] Figure 3 Thermal imaging camera pictures of cooling performance. DETAILED DESCRIPTION

[0035] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be understood as limiting the scope of implementation of the present invention. The following parts and proportions not specifically marked are all parts by weight. The particle size of the titanium carbide used is ≤2μm.

[0036] Comparative Example 1

[0037] This comparative example provides a waterproof and breathable polyvinylidene fluoride / polyurethane breathable film, which is prepared by the following steps:

[0038] First, 80 parts by weight of dimethylformamide organic solution was vigorously dispersed in a flask, and then 10 parts by weight of polyvinylidene fluoride powder and 10 parts by weight of polyurethane were slowly added to 80 parts by weight of dimethylformamide under vigorous stirring at 60°C to obtain a polymer solution; then, through electrospinning technology, a plastic syringe containing a uniform polymer solution (5mL) was used, and the electrospinning parameters were adjusted, with an additional voltage of 25kV and a syringe speed of 1.5mL / h, and the distance between the rolling collector and the syringe needle was set to 15 cm. A waterproof and breathable polyvinylidene fluoride / polyurethane breathable film with a thickness of 0.01mm was prepared.

[0039] Comparative Example 2

[0040] This comparative example provides a waterproof and breathable polyvinylidene fluoride / polyurethane breathable film, which is prepared by the following steps:

[0041] First, 80 parts by weight of dimethylformamide organic solution are vigorously dispersed in a flask, and then 10 parts by weight of polyvinylidene fluoride powder and 10 parts by weight of polyurethane are slowly added to 80 parts by weight of dimethylformamide under vigorous stirring at 60°C to obtain a polymer solution; then, through electrospinning technology, a plastic syringe containing a uniform polymer solution (5 mL) is used, and the electrospinning parameters are adjusted, a voltage of 25 kV and a syringe speed of 1.5 mL / h are applied, and the distance between the rolling collector and the syringe needle is set to 15 cm to obtain an initial polymer electrospinning film, and then the initial polymer electrospinning film is placed in 1 part by weight of sodium hydroxide alkaline solution and immersed for 5 minutes, and finally vacuum dried at 60°C for 24 hours to prepare a waterproof and breathable polyvinylidene fluoride / polyurethane breathable film with a thickness of 0.01 mm.

[0042] Comparative Example 3

[0043] This comparative example provides a waterproof and breathable polyvinylidene fluoride / polyurethane breathable film, which is prepared by the following steps:

[0044] First, 80 parts by weight of dimethylformamide organic solution are vigorously dispersed in a flask, and then 10 parts by weight of polyvinylidene fluoride powder and 10 parts by weight of polyurethane are slowly added to 80 parts by weight of dimethylformamide under vigorous stirring at 60°C to obtain a polymer solution; then, through electrospinning technology, a plastic syringe containing a uniform polymer solution (5 mL) is used, and the electrospinning parameters are adjusted, a voltage of 25 kV and a syringe speed of 1.5 mL / h are applied, and the distance between the rolling collector and the syringe needle is set to 15 cm to obtain an initial polymer electrospinning film, and then the initial polymer electrospinning film is placed in 2 parts by weight of sodium hydroxide alkaline solution and immersed for 5 minutes, and finally vacuum dried at 60°C for 24 hours to prepare a waterproof and breathable polyvinylidene fluoride / polyurethane breathable film with a thickness of 0.01 mm.

[0045] Comparative Example 4

[0046] This comparative example provides a waterproof and breathable polyvinylidene fluoride / polyurethane breathable film, which is prepared by the following steps:

[0047] First, 80 parts by weight of dimethylformamide organic solution are vigorously dispersed in a flask, and then 10 parts by weight of polyvinylidene fluoride powder and 10 parts by weight of polyurethane are slowly added to 80 parts by weight of dimethylformamide under vigorous stirring at 60°C to obtain a polymer solution; then, through electrospinning technology, a plastic syringe containing a uniform polymer solution (5 mL) is used, and the electrospinning parameters are adjusted, a voltage of 25 kV and a syringe speed of 1.5 mL / h are applied, and the distance between the rolling collector and the syringe needle is set to 15 cm to obtain an initial polymer electrospinning film, and then the initial polymer electrospinning film is placed in 4 parts by weight of sodium hydroxide alkaline solution and immersed for 5 minutes, and finally vacuum dried at 60°C for 24 hours to prepare a waterproof and breathable polyvinylidene fluoride / polyurethane breathable film with a thickness of 0.01 mm.

[0048] Comparative Example 5

[0049] This comparative example provides a polyurethane / titanium carbide high-emission moisture-permeable refrigeration film, which is prepared by the following steps:

[0050] First, 70 parts by weight of dimethylformamide organic solution were vigorously dispersed in a flask, and then polyurethane powder (20 parts by weight) and titanium carbide functional material (10 parts by weight) were slowly added to dimethylformamide under vigorous stirring at 60°C to obtain a functional material solution; then, through electrospinning technology, a plastic syringe containing a uniform functional material solution (5 mL) was used, and the electrospinning parameters were adjusted, an additional voltage of 25 kV and a syringe speed of 1.5 mL / h were applied, and the distance between the rolling collector and the syringe needle was set to 15 cm, to prepare a polyurethane / titanium carbide high-emissivity moisture-permeable refrigeration film with a thickness of 0.01 mm.

[0051] Comparative Example 6

[0052] This comparative example provides a polyurethane / titanium carbide high-emission moisture-permeable refrigeration film, which is prepared by the following steps:

[0053] First, 70 parts by weight of dimethylformamide organic solution were vigorously dispersed in a flask, and then polyurethane powder (20 parts by weight) and titanium carbide functional material (10 parts by weight) were slowly added to dimethylformamide under vigorous stirring at 60°C to obtain a functional material solution; then, through electrospinning technology, a plastic syringe containing a uniform functional material solution (5 mL) was used, and the electrospinning parameters were adjusted, a voltage of 25 kV and a syringe speed of 1.5 mL / h were applied, and the distance between the rolling collector and the syringe needle was set to 15 cm to obtain an initial polymer electrospun film, and then the initial polymer electrospun film was placed in 1 part by weight of sodium hydroxide alkaline solution and immersed for 5 minutes, and finally vacuum dried at 60°C for 24 hours to prepare a polyurethane / titanium carbide high-emissivity moisture-permeable refrigeration film with a thickness of 0.01 mm.

[0054] Comparative Example 7

[0055] This comparative example provides a polyurethane / titanium carbide high-emission moisture-permeable refrigeration film, which is prepared by the following steps:

[0056] First, 70 parts by weight of dimethylformamide organic solution were vigorously dispersed in a flask, and then polyurethane powder (20 parts by weight) and titanium carbide functional material (10 parts by weight) were slowly added to dimethylformamide under vigorous stirring at 60°C to obtain a functional material solution; then, through electrospinning technology, a plastic syringe containing a uniform functional material solution (5 mL) was used, and the electrospinning parameters were adjusted, a voltage of 25 kV and a syringe speed of 1.5 mL / h were applied, and the distance between the rolling collector and the syringe needle was set to 15 cm to obtain an initial polymer electrospun film, and then the initial polymer electrospun film was placed in 2 parts by weight of sodium hydroxide alkaline solution and immersed for 5 minutes, and finally vacuum dried at 60°C for 24 hours to prepare a polyurethane / titanium carbide high-emissivity moisture-permeable refrigeration film with a thickness of 0.01 mm.

[0057] Comparative Example 8

[0058] This comparative example provides a polyurethane / titanium carbide high-emission moisture-permeable refrigeration film, which is prepared by the following steps:

[0059] First, 70 parts by weight of dimethylformamide organic solution were vigorously dispersed in a flask, and then polyurethane powder (20 parts by weight) and titanium carbide functional material (10 parts by weight) were slowly added to dimethylformamide under vigorous stirring at 60°C to obtain a functional material solution; then, through electrospinning technology, a plastic syringe containing a uniform functional material solution (5 mL) was used, and the electrospinning parameters were adjusted, a voltage of 25 kV and a syringe speed of 1.5 mL / h were applied, and the distance between the rolling collector and the syringe needle was set to 15 cm to obtain an initial polymer electrospun film, and then the initial polymer electrospun film was placed in 4 parts by weight of sodium hydroxide alkaline solution and immersed for 5 minutes, and finally vacuum dried at 60°C for 24 hours to prepare a polyurethane@titanium carbide high-emissivity moisture-permeable refrigeration film with a thickness of 0.01 mm.

[0060] Comparative Example 9

[0061] This comparative example provides a polyurethane / titanium carbide high-emission moisture-permeable refrigeration film, which is prepared by the following steps:

[0062] First, 60 parts by weight of dimethylformamide organic solution were vigorously dispersed in a flask, and then polyurethane powder (20 parts by weight) and titanium carbide functional material (20 parts by weight) were slowly added to dimethylformamide under vigorous stirring at 60°C to obtain a functional material solution; then, through electrospinning technology, a plastic syringe containing a uniform functional material solution (5 mL) was used, and the electrospinning parameters were adjusted, a voltage of 25 kV and a syringe speed of 1.5 mL / h were applied, and the distance between the rolling collector and the syringe needle was set to 15 cm, to prepare a polyurethane / titanium carbide high-emissivity moisture-permeable refrigeration film with a thickness of 0.01 mm.

[0063] Comparative Example 10

[0064] This comparative example provides a polyurethane / titanium carbide high-emission moisture-permeable refrigeration film, which is prepared by the following steps:

[0065] First, 60 parts by weight of dimethylformamide organic solution were vigorously dispersed in a flask, and then polyurethane powder (20 parts by weight) and titanium carbide functional material (20 parts by weight) were slowly added to dimethylformamide under vigorous stirring at 60°C to obtain a functional material solution; then, through electrospinning technology, a plastic syringe containing a uniform functional material solution (5 mL) was used, and the electrospinning parameters were adjusted, a voltage of 25 kV and a syringe speed of 1.5 mL / h were applied, and the distance between the rolling collector and the syringe needle was set to 15 cm to obtain an initial polymer electrospun film, and then the initial polymer electrospun film was placed in 1 part by weight of sodium hydroxide alkaline solution and immersed for 5 minutes, and finally vacuum dried at 60°C for 24 hours to prepare a polyurethane / titanium carbide high-emissivity moisture-permeable refrigeration film with a thickness of 0.01 mm.

[0066] Comparative Example 11

[0067] This comparative example provides a polyurethane / titanium carbide high-emission moisture-permeable refrigeration film, which is prepared by the following steps:

[0068] First, 60 parts by weight of dimethylformamide organic solution were vigorously dispersed in a flask, and then polyurethane powder (20 parts by weight) and titanium carbide functional material (20 parts by weight) were slowly added to dimethylformamide under vigorous stirring at 60°C to obtain a functional material solution; then, through electrospinning technology, a plastic syringe containing a uniform functional material solution (5 mL) was used, and the electrospinning parameters were adjusted, a voltage of 25 kV and a syringe speed of 1.5 mL / h were applied, and the distance between the rolling collector and the syringe needle was set to 15 cm to obtain an initial polymer electrospun film, and then the initial polymer electrospun film was placed in 2 parts by weight of sodium hydroxide alkaline solution and immersed for 5 minutes, and finally vacuum dried at 60°C for 24 hours to prepare a polyurethane / titanium carbide high-emissivity moisture-permeable refrigeration film with a thickness of 0.01 mm.

[0069] Comparative Example 12

[0070] This comparative example provides a polyurethane / titanium carbide high-emission moisture-permeable refrigeration film, which is prepared by the following steps:

[0071] First, 60 parts by weight of dimethylformamide organic solution were vigorously dispersed in a flask, and then polyurethane powder (20 parts by weight) and titanium carbide functional material (20 parts by weight) were slowly added to dimethylformamide under vigorous stirring at 60°C to obtain a functional material solution; then, through electrospinning technology, a plastic syringe containing a uniform functional material solution (5 mL) was used, and the electrospinning parameters were adjusted, a voltage of 25 kV and a syringe speed of 1.5 mL / h were applied, and the distance between the rolling collector and the syringe needle was set to 15 cm to obtain an initial polymer electrospun film, and then the initial polymer electrospun film was placed in 4 parts by weight of sodium hydroxide alkaline solution and immersed for 5 minutes, and finally vacuum dried at 60°C for 24 hours to prepare a polyurethane / titanium carbide high-emissivity moisture-permeable refrigeration film with a thickness of 0.01 mm.

[0072] Example 1

[0073] This embodiment provides a double-layer quick-drying, moisture-permeable, high-emission refrigeration film, the process flow is as follows: Figure 1 As shown, it is prepared by the following steps:

[0074] First, two electrospinning original solutions were prepared at the same time. An organic solution of dimethylformamide (80 parts by weight) was vigorously dispersed in a flask, and then polyvinylidene fluoride powder (10 parts by weight) and polyurethane powder (10 parts by weight) were slowly added to the dimethylformamide solution under vigorous stirring at 60°C to obtain a polymer solution; 70 parts by weight of the dimethylformamide organic solution was vigorously dispersed in a flask, and then polyurethane powder (20 parts by weight) and titanium carbide functional material (10 parts by weight) were slowly added to the dimethylformamide under vigorous stirring at 60°C to obtain a functional material solution; and then, through electrospinning technology, a plastic syringe containing a uniform polymer solution (5 mL) was used, and the electrospinning parameters were adjusted, and an external The voltage was 25 kV and the syringe speed was 0.5 mL / h, and the distance between the rolling collector and the syringe needle was set to 15 cm to obtain an initial polymer electrospinning film. Then, an electrospinning solution containing titanium carbide powder (functional material solution) was electrospun for a second time on the initial polymer electrospinning film using electrospinning technology to obtain a double-layer initial polymer electrospinning film (double-layer membrane). Then, the double-layer initial polymer electrospinning film was immersed in 2 parts by weight of sodium hydroxide alkaline solution for 5 minutes, and finally vacuum dried at 60°C for 24 hours to obtain a polyvinylidene fluoride / polyurethane-polyurethane / polyurethane double-layer quick-drying, moisture-permeable, and highly emissive refrigeration film with a thickness of 0.01 mm.

[0075] Example 2

[0076] This embodiment provides a double-layer quick-drying, moisture-permeable, and highly emissive refrigeration film, which is prepared by the following steps:

[0077] First, two electrospinning original solutions were prepared at the same time. An organic solution of dimethylformamide (80 parts by weight) was vigorously dispersed in a flask, and then polyvinylidene fluoride powder (10 parts by weight) and polyurethane powder (10 parts by weight) were slowly added to the dimethylformamide under vigorous stirring at 60°C to obtain a polymer solution; 60 parts by weight of the dimethylformamide organic solution was vigorously dispersed in a flask, and then polyurethane powder (20 parts by weight) and titanium carbide functional material (20 parts by weight) were slowly added to the dimethylformamide solution under vigorous stirring at 60°C to obtain a functional material solution; and then, through electrospinning technology, a plastic syringe containing a uniform polymer solution (5 mL) was used, and the electrospinning parameters were adjusted, and an external The voltage was 25 kV and the syringe speed was 0.5 mL / h, and the distance between the rolling collector and the syringe needle was set to 15 cm to obtain an initial polymer electrospinning film. Then, an electrospinning solution containing titanium carbide powder (functional material solution) was electrospun for a second time on the initial polymer electrospinning film using electrospinning technology to obtain a double-layer initial polymer electrospinning film (double-layer membrane). Then, the double-layer initial polymer electrospinning film was immersed in 2 parts by weight of sodium hydroxide alkaline solution for 5 minutes, and finally vacuum dried at 60°C for 24 hours to obtain a polyvinylidene fluoride / polyurethane-polyurethane / polyurethane double-layer quick-drying, moisture-permeable, and highly emissive refrigeration film with a thickness of 0.01 mm.

[0078] Performance Testing

[0079] The films obtained in the above embodiments and comparative examples were tested, and the results of their refrigeration performance, WVT (water vapor transmission rate), and complete drying time are shown in Table 1; the thermal imaging image of the refrigeration performance is shown in Figure 2 and Figure 3 As shown, Figure 2 In the figure, from left to right and from top to bottom are the thermal images of Comparative Examples 1 to Comparative Examples 8, Figure 3 In the figure, from left to right and from top to bottom are the thermal imaging images of Comparative Example 9-Comparative Example 12 and Example 1-Example 2.

[0080] The refrigeration performance is tested using the ASTM E1594-16 standard and the German TESTO 871 infrared thermal imager.

[0081] The moisture permeability test was conducted using the ASTM E96 BW standard using a Haida HD-100T constant temperature and humidity chamber (conditions: temperature of 25° C., relative humidity of 50%).

[0082] The complete drying time of the film was measured by the finger contact method according to GB / T 1728-79(86) standard.

[0083] Table 1

[0084] project Refrigeration performance (℃) <![CDATA[Water vapor transmission rate (kg·m 2 d -1 )]]> Complete drying time (min) Comparative Example 1 2.0 18.779 15.1 Comparative Example 2 1.9 17.221 15.5 Comparative Example 3 2.0 17.548 14.9 Comparative Example 4 2.1 18.562 15.2 Comparative Example 5 3.0 16.456 11.8 Comparative Example 6 3.2 22.364 10.5 Comparative Example 7 3.1 26.805 8.3 Comparative Example 8 3.0 - - Comparative Example 9 4.1 17.922 8.6 Comparative Example 10 4.1 25.325 7.9 Comparative Example 11 4.3 32.804 7.2 Comparative Example 12 4.2 - - Example 1 2.8 21.351 6.8 Example 2 4.1 25.558 4.5

[0085] As can be seen from Table 1, by comparing Comparative Examples 1-4, 5-8, and 9-12, the refrigeration performance results show that as the concentration of alkali treatment increases, the refrigeration temperature of the resulting film does not increase significantly; as the content of the functional material titanium carbide increases, the refrigeration temperature increases from 2°C to 4°C. It can be seen from Examples 1 and 2 that the refrigeration temperature also increases from 2.8°C to 4.1°C. By comparison, it can be seen that with the addition of thermal conductive functional materials, the refrigeration performance of the resulting film is significantly enhanced. Specifically, this is because the introduction of thermal conductive functional materials changes the thermal conductivity of the film and accelerates heat dissipation.

[0086] By comparing the moisture permeability results of Examples 1-4, 5-8, and 9-12, it can be seen that with the increase of the concentration of alkali treatment, there is no obvious improvement in Examples 1-4, which is about 17-18 kg·m 2 d -1 The moisture permeability of Comparative Examples 5-8 and 9-12 increases with the increase of alkali concentration. It can be seen from Examples 1 and 2 that under the same alkali concentration treatment conditions, the moisture permeability also increases from 21kg·m 2 d -1 Increased to 25kg·m 2 d -1 The comparison shows that the moisture permeability of the obtained film is significantly enhanced with the addition of alkali concentration. This is because the introduction of hydrophilic groups and the increase of water molecule channels after alkali treatment change the hydrophilicity of the film, accelerate water penetration, and thus improve moisture permeability.

[0087] By comparing the comparative examples 1-4, 5-8, and 9-12, it can be seen from the results of the complete drying time that as the concentration of the alkali treatment increases, the complete drying time of the comparative examples 1-4 lasts for a relatively long time, about 15 minutes, and there is no obvious change; the moisture permeability of the comparative examples 5-8 and 9-12 shows a trend of obvious reduction in the complete drying time as the alkali concentration increases. Through the double-layer membrane embodiment 1 and embodiment 2, under the conditions of the same alkaline concentration treatment, the complete drying time is also reduced from 6.8 minutes to 4.5 minutes. By comparison, it can be seen that with the addition of the alkali concentration, the complete drying time of the obtained membrane is significantly reduced. Specifically, it is because the introduction of hydrophilic groups and the increase of water molecule channels after the alkali treatment change the hydrophilicity of the film, accelerate the penetration of water, and thus improve the moisture permeability; the complete drying time of the double-layer membrane is significantly reduced than that of the single-layer membrane, because the double-layer membrane has a hydrophobic layer and a hydrophilic layer, and the hydrophobic layer hinders the reverse osmosis of water molecules, and the water molecules are quickly transported from the hydrophobic layer to the hydrophilic layer, and then rapidly diffuse in the hydrophilic layer, thereby reducing the time for complete drying. For a single layer, it is difficult for water molecules to penetrate the hydrophobic film, while the hydrophilic film molecules diffuse and penetrate in both directions, so that some of the reversely permeated water molecules still exist in the film and cannot be dried in time.

Claims

1. A double-layer quick-drying, moisture-permeable, high-emissivity refrigeration film, comprising a hydrophilic layer and a hydrophobic layer; in, The hydrophilic layer contains titanium carbide and polyurethane, the hydrophobic layer contains polyvinylidene fluoride and adhesive, and the double-layer quick-drying, moisture-permeable and highly emissive refrigeration film also contains alkaline substances; Preferably, the adhesive is polyurethane.

2. The double-layer quick-drying, moisture-permeable, high-emissivity refrigeration film according to claim 1, wherein: Calculated by weight, the double-layer quick-drying, moisture-permeable, high-emissivity refrigeration film comprises less than 10 parts of polyvinylidene fluoride, less than 30 parts of titanium carbide, 10-30 parts of polyurethane, and less than 10 parts of alkaline substances; Preferably, in the hydrophilic layer, the weight ratio of titanium carbide to polyurethane is 0.1-1:1; Preferably, in the hydrophobic layer, the weight ratio of the polyvinylidene fluoride to the polyurethane is 0.1-1:

1.

3. The double-layer quick-drying, moisture-permeable, high-emissivity refrigeration film according to claim 1, wherein: The alkaline substance comprises sodium hydroxide; Preferably, the particle size of the titanium carbide is ≤2 μm, more preferably 0.5-1 μm.

4. The double-layer quick-drying, moisture-permeable, high-emissivity refrigeration film according to claim 1, wherein: The thickness of the double-layer quick-drying, moisture-permeable and highly emissive refrigeration film is 0.01-0.015 mm; Preferably, the moisture permeability of the double-layer quick-drying, moisture-permeable, high-emissivity refrigeration film is greater than 12000 g·m 2 / 24h; Preferably, the cooling temperature of the double-layer quick-drying, moisture-permeable and highly emissive cooling film is greater than 2°C.

5. The method for preparing the double-layer quick-drying, moisture-permeable and highly emissive refrigeration film according to any one of claims 1 to 4, comprising the following steps: (1) mixing and dispersing polyvinylidene fluoride and an adhesive in a solvent to obtain a polymer solution; mixing and dispersing titanium carbide and polyurethane in a solvent to obtain a functional material solution; (2) preparing the polymer solution into a moisture permeable film, and then applying the functional material solution onto the surface of the moisture permeable film to form a high-emission moisture permeable refrigeration film to obtain a double-layer film; (3) The double-layer film is subjected to alkali treatment and vacuum drying to obtain the double-layer quick-drying, moisture-permeable and highly emissive refrigeration film.

6. The preparation method according to claim 5, wherein: In step (1), the mixing and dispersing temperature is 50-60°C; Preferably, the solvent of the polymer solution and the functional material solution comprises one or a combination of two or more of dimethylformamide, tetrahydrofuran, and acetone, more preferably dimethylformamide; Preferably, the amount of dimethylformamide used is 80 parts or less.

7. The preparation method according to claim 5, wherein: The moisture-permeable film and the high-emission moisture-permeable refrigeration film are formed by adopting the electrostatic spinning technology.

8. The preparation method according to claim 7, wherein: The voltage of electrospinning was 20-25 KV, the syringe advancement rate was 0.3-0.5 mL / h, and the collection distance was 12-15 cm.

9. The preparation method according to claim 5, wherein: In step (3), the alkali treatment is performed by soaking in a sodium hydroxide solution for 5-10 minutes.

10. Application of the double-layer quick-drying, moisture-permeable, and highly emissive refrigeration film according to any one of claims 1 to 4 in the fields of refrigeration clothing, moisture-permeable clothing, building structure fabrics, and smart wearables.

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