Temperature and humidity adjustable fabric

Abstract

The invention discloses a temperature and humidity adjustable fabric. The fabric is woven from a composite fiber membrane, and the composite fiber membrane includes: a porous fiber layer and a heat-insulating reflective layer. The porous fiber layer is woven from a porous fiber membrane, wherein the porous fiber membrane has both radiative cooling and osmotic dehumidification functions; the heat-insulating reflective layer is a polyethylene aerogel with good thermal insulation performance and high reflectivity in the solar band (0.25-2.5 μm). The new fabric can achieve passive cooling, so that the surface temperature is reduced. At the same time, the new fabric can achieve perspiration and moisture permeability functions, thereby improving wearing comfort.

Description

Technical Field

[0001] The invention relates to a novel radiation cooling fabric, belonging to the technical field of passive energy utilization. Background Art

[0002] The huge amount of energy used in modern society has led to a sharp decline in the earth's energy reserves, so a passive radiation cooling technology without external energy consumption has received more and more attention. Radiative cooling technology is a new type of refrigeration technology in which radiation cooling materials emit electromagnetic waves through the atmospheric window (8-13μm) to outer space (temperature close to absolute zero), exchange heat with outer space, and then reduce the surface temperature of the material. Radiative cooling does not require any external energy input and can effectively alleviate the problem of large energy consumption.

[0003] Nowadays, due to the intensification of global warming, the outdoor temperature in summer has reached new highs, posing a great threat to the health of outdoor workers. Therefore, individual cooling has become increasingly important, and the design of individual passive cooling clothing using radiant cooling technology has great application prospects.

[0004] Professor Cui's team at Stanford University1 prepared porous composite PE fibers by extrusion and phase separation. In the test, the skin temperature covered with nanoporous PE fabric was 2.3℃ lower than that covered with cotton fabric. The principle is as follows: the porous composite fiber has air holes of 50-1000nm. Since the diameter of the air holes is equivalent to the solar band (0.25-2.5μm), the fiber can effectively reflect sunlight. At the same time, since PE has a high transmittance in the infrared band, the infrared thermal radiation of the human body can be emitted outward through the clothing made of PE fiber, thereby reducing the temperature of the human skin surface. However, since the porous PE fiber itself does not have a high atmospheric window emissivity, its actual cooling effect is limited. Chinese patent CN110042564A discloses a radiation cooling composite fiber membrane and its preparation method and application, wherein the highly emissive radiation particle silica particles with good monodispersity are evenly dispersed in a polymer solution, and the composite fiber membrane is obtained by electrospinning, and the radiation cooling effect is more obvious. However, the composite fiber produced by this method has poor air permeability and perspiration performance, and the preparation process is complicated and the equipment cost is high.

[0005] In summary, the prior art lacks a design solution for a new type of radiant cooling fabric that simultaneously satisfies radiant cooling, breathability and sweat removal, and UV blocking. To solve this problem, the present invention proposes a new type of temperature and humidity adjustable fabric woven from a composite fiber membrane.

[0006] References:

[0007] [1]Hsu, PC; Song, AY; Catrysse, PB; Liu, C.; Peng, YC; Summary of the invention

[0008] The invention discloses a temperature and humidity adjustable fabric, which has both radiant cooling performance and breathable perspiration-releasing performance, and provides a design scheme for passive cooling clothing for human body.

[0009] The temperature and humidity adjustable fabric is woven from a composite fiber membrane.

[0010] The composite fiber membrane comprises a porous fiber membrane with radiation cooling performance and penetration dehumidification performance and a heat insulation reflection layer with high thermal resistance and high reflection.

[0011] The porous fiber membrane has the function of blocking liquid droplets, preventing the liquid droplets from wetting the radiation cooling material and reducing its radiation cooling capacity;

[0012] The porous fiber membrane comprises a polymer material and a material having a radiation cooling property;

[0013] The polymer material is PVDF or PTFE; the material having the performance of radiation cooling is one of PDMS, PVDF, Al2O3, SiC, SiO2, MgO, and BaSO4.

[0014] The preparation process of the textile fabric can adopt the following two schemes:

[0015] Solution 1 is to mix PVDF and radiation cooling material Al2O3 to make a casting solution, and then obtain Al2O3 / PVDF composite fiber membrane by spinning, and then weave it into fabric, specifically including:

[0016] (1) adding a certain amount of Al2O3 to dimethylformamide (DMF), stirring the mixture with ultrasonic waves at 65°C for 2 hours, wherein the mass ratio of Al2O3 to DMF is 1:30-40;

[0017] (2) adding PVDF powder to the above solution, stirring at 65°C for 2 hours under constant temperature and ultrasonic conditions, wherein the mass ratio of the PVDF powder to Al2O3 is 1:6-8;

[0018] (3) adding a porogen to the above-mentioned mixed solution, stirring ultrasonically for 2 hours, and then standing and degassing for 48 hours after stopping stirring to obtain a casting solution, wherein the porogen is polyvinyl pyrrolidone (PVP) or polyurethane (PU), and the mass ratio of PVP to PVDF is 1:3-5;

[0019] (4) pouring the above-mentioned casting solution into a melt spinning device, passing the casting solution extruded from the spinneret through a gel tank, precipitating gel, eluting and soaking in water, and then placing in a cool place to dry to obtain an Al2O3 / PVDF porous fiber membrane; the gel tank has a cross section such as Figure 2 The structure shown is used to prepare a porous fiber membrane with a special shape;

[0020] (5) The Al2O3 / PVDF porous fiber membrane is subjected to a hydrophilic treatment to obtain a hydrophilic Al2O3 / PVDF porous fiber membrane.

[0021] (6) placing the hydrophilic Al2O3 / PVDF porous fiber membrane with a special shape into an extrusion device, and covering the surface of the hydrophilic Al2O3 / PVDF porous fiber membrane with a heat insulating reflective layer by extrusion to obtain a composite fiber membrane with a complete cylindrical shape; the heat insulating reflective layer is polyethylene aerogel;

[0022] (7) The composite fiber membrane is weaved, and the heat insulating reflective layer always maintains a uniform direction during weaving, thereby finally obtaining a composite fiber membrane textile.

[0023] The second method is to dissolve the radiation cooling material polydimethylsiloxane (PDMS) to obtain a PDMS film-making solution, take a PVDF porous fiber, immerse it in the PDMS film-making solution for a period of time, obtain a PDMS / PVDF porous fiber, and then weave it to obtain a PDMS / PVDF fabric, which specifically includes:

[0024] (1) First, PDMS is dissolved in an organic solvent in a certain proportion, and then a cross-linking agent is added and mixed and stirred for 2 hours, and then a catalyst is added, and magnetic stirring is performed at room temperature for 8 hours, centrifuged, and then allowed to stand for 24 hours to degas to prepare a PDMS film-forming solution; the organic solvent is n-hexane, the mass fraction of PDMS in the film-forming solution is 12%, the cross-linking agent is tetraethyl orthosilicate, the mass ratio of PDMS to tetraethyl orthosilicate is 1:0.1, and the catalyst is dibutyltin dilaurate, and the mass ratio of PDMS to dibutyltin dilaurate is 1:20;

[0025] (2) dissolving PVDF and PEG in a certain proportion in an organic solvent DMAC, stirring the mixture at 65° C. under constant temperature magnetic stirring until the mixture is uniform, and then standing until there are no bubbles, to obtain a casting solution; the mass proportions of the PVDF, PEG, and DMAC are 10%-20%, 2%-15%, and 65%-80%, respectively.

[0026] (3) adding the above-mentioned casting solution to a melt spinning machine, passing the casting solution extruded from the spinneret through a gel tank, precipitating gel, eluting and soaking in water, and then placing in a cool place to dry, thereby obtaining a PVDF porous fiber membrane;

[0027] (4) immersing the PVDF porous fiber membrane in the above-mentioned PDMS membrane-forming solution for 3 seconds, then taking it out and drying it at room temperature, repeating the above-mentioned immersion and drying operations for 3 times, and then placing it in a vacuum oven at 80° C. to vacuum dry it to obtain a PDMS / PVDF porous fiber membrane;

[0028] (5) The above-mentioned PDMS / PVDF porous fiber membrane is subjected to hydrophilic treatment, and the obtained hydrophilic Al2O3 / PVDF composite fiber membrane is placed in a cross-section such as Figure 2 In the device shown, PVDF casting solution is injected to produce a hydrophilic PDMS / PVDF porous fiber membrane with a special shape;

[0029] (6) placing the hydrophilic PDMS / PVDF porous fiber membrane with a special shape into an extrusion device, and covering the surface of the PDMS / PVDF porous fiber membrane with a heat insulating reflective layer by extrusion to obtain a composite fiber membrane with a complete cylindrical shape; the heat insulating reflective layer is polyethylene aerogel;

[0030] (7) The composite fiber membrane is weaved, and the heat insulating reflective layer always maintains a uniform direction during weaving, thereby finally obtaining a composite fiber membrane textile.

[0031] The heat-insulating reflective layer is an aerogel film with good thermal insulation performance, high solar spectrum band (0.25-2.5μm) reflectivity and high atmospheric window (8-13μm) transparency. The thermal conductivity of the aerogel is not higher than 0.05W / m·K, the solar spectrum band reflectivity is higher than 0.85, the atmospheric window band transmittance is higher than 0.8, and the aerogel thickness is 50μm-5mm.

[0032] The aerogel layer is polyethylene aerogel or an aerogel with a thermal conductivity not higher than 0.05 W / m·K, a reflectivity higher than 0.85 in the solar spectrum band (0.25-2.5 μm), and a transmittance higher than 0.8 in the atmospheric window band (8-13 μm).

[0033] The polyethylene aerogel has a strong reflection effect on ultraviolet rays (0.25-0.6 μm) in the solar band, and the reflectivity is greater than 70%.

[0034] The temperature and humidity adjustable fabric can be designed into protective clothing and used in specific environments.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The temperature and humidity adjustable fabric proposed by the present invention has the functions of radiation cooling, breathable perspiration and reduced ultraviolet light absorption. Among them, the composite fiber membrane has a low preparation cost. By combining the polymer material with the radiation cooling material, it can not only realize individual passive cooling, but also can pass water vapor, which is conducive to the discharge of sweat and ensures the comfort of the human body; the aerogel material has the functions of heat preservation and sunlight reflection. The combination of composite fiber and aerogel material is conducive to enhancing the radiation cooling effect and reducing the absorption of ultraviolet rays. Clothes made of this fabric are conducive to improving the comfort of outdoor workers in summer and preventing heat stroke. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 : A schematic diagram of a temperature and humidity adjustable fabric;

[0038] Figure 2 : Schematic diagram of the cross section of the porous fiber membrane preparation device;

[0039] Figure 3 : Schematic diagram of partial pressure of water vapor inside and outside the woven fabric;

[0040] In the figure: 1 is a composite fiber fabric; 2 is a polyethylene aerogel; 3 is a PVDF porous fiber. DETAILED DESCRIPTION

[0041] In order to better understand the present invention, specific embodiments are listed below to further illustrate the present invention. However, the content of the present invention is by no means limited to the following embodiments:

[0042] Embodiment 1:

[0043] (1) First prepare the PDMS membrane solution, and then prepare the PDMS / PVDF porous fiber membrane by the pulling method. The specific process is as follows:

[0044] First, 100g of PDMS was dissolved in 1000g of n-hexane, and then ethyl orthosilicate was added and mixed and stirred for 2 hours, and then 2000g of dibutyltin dilaurate was added, and magnetic stirring was performed at room temperature for 8 hours, centrifuged, and then allowed to stand for 24 hours to degas to prepare a membrane-making solution; a pure PVDF composite fiber membrane was taken, and it was immersed in the above PDMS membrane-making solution for 3 seconds, and then taken out and dried at room temperature, and the above immersion and drying operations were repeated 3 times, and then placed in a vacuum oven at 80°C for vacuum drying for 8 hours to prepare a PDMS / PVDF porous fiber membrane;

[0045] (2) Place the above PDMS / PVDF porous fiber membrane into a cross-section Figure 2 In the device shown, PVDF casting solution is injected to produce a PDMS / PVDF porous fiber membrane with a special shape;

[0046] (3) The PDMS / PVDF porous fiber membrane with a special shape is subjected to a hydrophilic treatment, and the obtained hydrophilic PDMS / PVDF porous fiber membrane is placed in an extrusion device, and the polyethylene aerogel is covered on the surface of the PDMS / PVDF porous fiber membrane by extrusion to obtain a composite fiber membrane with a complete cylindrical shape;

[0047] (4) Take a plurality of porous fiber membranes and weave the parts with polyethylene aerogel upward to obtain the corresponding woven fabric. Since the PDMS / PVDF porous fiber membrane is hydrophilic, it will concentrate the sweat on the inner surface of the fabric, forming a water vapor pressure difference between the inner and outer surfaces of the fabric (such as Figure 3 As shown), driven by the pressure difference, the sweat vapor will be discharged, thus achieving the effect of sweating and dehumidification;

[0048] (6) The fabric with temperature and humidity regulation function composed of PDMS / PVDF fabric and aerogel is designed into protective clothing. When designing, it should be noted that the aerogel layer faces outward and the fiber layer faces inward.

[0049] The clothing is made of temperature and humidity regulating fabrics, in which PDMS / PVDF composite fibers use the high emissivity of PDMS and PVDF at the atmospheric window to emit energy into outer space, and then use the high solar reflectivity of the polyethylene aerogel on the upper layer of the fabric to reduce the input of solar energy, thereby achieving a cooling effect; at the same time, the surface of the porous fiber membrane has pores of a specific size, which can selectively pass water vapor; in summary, this clothing is beneficial for outdoor workers in summer to cool down and sweat, and prevent heatstroke.

[0050] Embodiment 2:

[0051] 10 g of Al2O3 was added to 300 g of dimethylformamide (DMF), and the mixture was ultrasonically stirred at 65°C for 2 hours. 1.5 g of PVDF powder was added to the mixture, and the mixture was ultrasonically stirred at 65°C for 2 hours. 0.5 g of porogen PVP was added to the mixture, and the mixture was ultrasonically stirred for 2 hours. After the stirring was stopped, the mixture was allowed to stand for 48 hours to degas, and a casting solution was obtained. The casting solution was poured into a melt spinning device, and the casting solution extruded from the spinneret was passed through a gel tank to precipitate gel, and then rinsed and soaked in water. , place it in a cool place to dry to obtain an Al2O3 / PVDF composite fiber membrane, which is subjected to a hydrophilic treatment to obtain a hydrophilic Al2O3 / PVDF composite fiber membrane; the hydrophilic Al2O3 / PVDF composite fiber membrane is placed in an extrusion device, and the polyethylene aerogel is covered on the surface of the Al2O3 / PVDF composite fiber membrane by extrusion to obtain a composite fiber membrane; the composite fiber membrane is weaved to ensure that the polyethylene aerogel always maintains a uniform direction during weaving to obtain a composite fiber membrane textile.

Claims

1. A temperature and humidity adjustable fabric, characterized in that: It is woven from a composite fiber membrane; the composite fiber membrane comprises a heat-insulating reflective layer (2) and a porous fiber membrane layer (3); The porous fiber membrane comprises a polymer material and a material having a radiation cooling property; The pore size of the porous fiber membrane is between that of water vapor molecules and water clusters, and water vapor molecules can pass through but small water droplets cannot, that is, it has permeation dehumidification. At the same time, the radiation refrigeration material exchanges heat with the outer space by emitting infrared electromagnetic waves to the outer space, thereby reducing the surface temperature of the fiber; The heat-insulating reflective layer (2) is an aerogel film; The aerogel film is polyethylene aerogel or an aerogel having a thermal conductivity of no more than 0.05 W / m∙K, a reflectivity of a solar spectrum band higher than 0.85, and a transmittance of an atmospheric window band higher than 0.8, and the aerogel thickness is 50 μm-1 mm; The polyethylene aerogel has a strong reflective effect on ultraviolet rays in the solar band, with a reflectivity greater than 70%; The preparation process of the temperature and humidity adjustable fabric adopts one of the following two schemes: Solution 1 is to mix PVDF and radiation cooling material Al2O3 to make a casting solution, and then obtain Al2O3 / PVDF composite fiber membrane by spinning, and then weave it into fabric, specifically including: (1) adding a certain amount of Al2O3 to dimethylformamide (DMF), stirring at 65°C for 2 hours with ultrasonic stirring, wherein the mass ratio of Al2O3 to DMF is 1:30-40; (2) adding PVDF powder to the above solution, stirring at 65°C for 2 hours under constant temperature and ultrasonic stirring, wherein the mass ratio of PVDF powder to Al2O3 is 1:6-8; (3) adding a porogen to the above-mentioned mixed solution, stirring with ultrasound for 2 hours, and then standing and degassing for 48 hours after stopping stirring to obtain a casting solution, wherein the porogen is polyvinyl pyrrolidone (PVP) or polyurethane (PU), and the mass ratio of PVP to PVDF is 1:3-5; (4) pouring the above-mentioned casting solution into a melt spinning device, passing the casting solution extruded from the spinneret through a gel tank, precipitating the gel, eluting and soaking in water, and then placing in a cool place to dry, thereby obtaining an Al2O3 / PVDF porous fiber membrane; (5) treating the Al2O3 / PVDF porous fiber membrane to make it hydrophilic, thereby obtaining a hydrophilic Al2O3 / PVDF porous fiber membrane; (6) placing the hydrophilic Al2O3 / PVDF porous fiber membrane into an extrusion device, and covering the heat insulating reflective layer (2) on the surface of the hydrophilic Al2O3 / PVDF porous fiber membrane by extrusion to obtain a composite fiber membrane with a complete cylindrical shape; (7) weaving the composite fiber membrane, wherein the heat insulating reflective layer (2) always maintains a uniform orientation during weaving, thereby finally obtaining a composite fiber membrane textile; The second method is to dissolve the radiation cooling material polydimethylsiloxane (PDMS) to obtain a PDMS film-making solution, take a PVDF porous fiber, immerse it in the PDMS film-making solution for a period of time, obtain a PDMS / PVDF porous fiber, and then weave it to obtain a PDMS / PVDF fabric, which specifically includes: (1) First, PDMS is dissolved in an organic solvent in a certain proportion, and then a cross-linking agent is added and mixed and stirred for 2 hours, and then a catalyst is added, and magnetic stirring is performed at room temperature for 8 hours, centrifuged, and then allowed to stand for 24 hours to degas to prepare a PDMS film-forming solution; the organic solvent is n-hexane, the mass fraction of PDMS in the film-forming solution is 12%, the cross-linking agent is tetraethyl orthosilicate, and the mass ratio of PDMS to tetraethyl orthosilicate is 1:0.1, and the catalyst is dibutyltin dilaurate, and the mass ratio of PDMS to dibutyltin dilaurate is 1:20; (2) dissolving PVDF and PEG in a certain proportion in an organic solvent DMAC, stirring the mixture at 65°C with a constant temperature magnetic force until the mixture is uniform, and then standing the mixture until there are no bubbles, to obtain a casting solution; the mass proportions of PVDF, PEG and DMAC are 10%-20%, 2%-15% and 65%-80% respectively; (3) adding the above-mentioned casting solution into a melt spinning machine, and passing the casting solution extruded from the spinneret through a gel tank to precipitate gel, and then eluting and soaking in water, and then placing in a cool place to dry, thereby obtaining a PVDF porous fiber membrane; (4) Immerse the PVDF porous fiber membrane in the above-mentioned PDMS membrane-forming solution for 3 seconds, then take it out and dry it at room temperature, repeat the above-mentioned membrane immersion and drying operation 3 times, and then put it into a vacuum oven at 80°C for vacuum drying to obtain a PDMS / PVDF porous fiber membrane; (5) subjecting the PDMS / PVDF porous fiber membrane to a hydrophilic treatment and injecting a casting solution to obtain a hydrophilic PDMS / PVDF porous fiber membrane; (6) placing the hydrophilic PDMS / PVDF porous fiber membrane into an extrusion device, and covering the heat insulating reflective layer (2) on the surface of the PDMS / PVDF porous fiber membrane by extrusion to obtain a composite fiber membrane with a complete cylindrical shape; (7) Weaving the composite fiber membrane, wherein the heat insulating reflective layer (2) always maintains a uniform orientation during weaving, thereby finally obtaining a composite fiber membrane textile.

Images