CN115323801A

CN115323801A - Coated textile with all-day efficient passive radiation cooling function and preparation method thereof

Info

Publication number: CN115323801A
Application number: CN202211123713.8A
Authority: CN
Inventors: 苏娟娟; 崔超凡; 韩建
Original assignee: Zhejiang Sci Tech University ZSTU
Current assignee: Zhejiang Sci Tech University ZSTU
Priority date: 2022-07-12
Filing date: 2022-09-15
Publication date: 2022-11-11
Anticipated expiration: 2042-09-15
Also published as: CN115323801B

Abstract

The invention provides a coated textile with an all-day efficient passive radiation cooling function and a preparation method thereof. Compared with a pure porous coating fabric or a coating fabric only added with inorganic particles, the coating textile prepared by the invention has higher radiation refrigeration effect. Meanwhile, the coated textile has good hydrophobicity, can ensure outdoor durability of cooling performance, and endows the coated textile with self-cleaning performance. The preparation method of the coated textile is simple, the cost is low, and the addition amount of the inorganic particles is small.

Description

Coated textile with all-day efficient passive radiation cooling function and preparation method thereof

Technical Field

The invention belongs to the technical field of radiation cooling materials, and particularly relates to a coated textile with an all-day efficient passive radiation cooling function and a preparation method thereof.

Background

Energy for cooling is consumed at a rate of about 52.3EJ each year, accounting for about 14.6% of global energy demand. The increasing power consumption increases global demand for energy and also brings environmental problems such as greenhouse effect. The radiation cooling technology utilizes the huge temperature difference between the earth and the universe to promote the thermal radiation emitted by the ground to penetrate through a middle infrared atmospheric window (the wavelength is about 8-13 mu m), thereby achieving the cooling effect. Atmospheric windows are dynamic behaviors of the earth's atmosphere that allow infrared radiation of a particular wavelength to pass through the atmosphere without being absorbed. The outer space is used as a huge cold source, and the temperature of the earth object can be reduced to be lower than the environmental temperature by carrying out radiation heat exchange with the outer space. Compared with the traditional cooling technology, the radiation cooling technology is more and more widely concerned and researched as a passive cooling technology without energy consumption and greenhouse gas emission.

The radiation cooling fabric is prepared in two ways, including composite spinning technology and coating technology. The fiber product prepared by the composite spinning technology has excellent radiation cooling performance, but the addition amount of the functional filler is large, so that the spinning processing difficulty is large, and the physical and mechanical properties of the fiber product are poor. The coating technology has higher applicability and flexibility, and the coated fabric with the radiation cooling performance can be obtained through the design of the coating composition and the structure. However, the coating technology has many problems of the cooling effect to be improved, the preparation process to be complicated, the cost to be high and the like, and the wide application of the radiation cooling technology in the textile field is greatly limited.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides the radiation refrigeration functional coating textile which is low in cost, can be prepared in a large area and is high in radiation refrigeration efficiency and the preparation method thereof, and solves the problems of poor cooling performance of a radiation refrigeration layer, complex preparation process, high cost and the like in the prior art.

A coating textile with an all-day high-efficiency passive radiation cooling function comprises a substrate and a radiation refrigerating layer which is arranged on the substrate and has inorganic particles and a porous structure;

the porosity of the radiation refrigerating layer is 0-50%.

Wherein, the inorganic particles and the porous structure are respectively and independently distributed on the surface and in the radiation refrigeration layer.

The radiation refrigerating layer with inorganic particles and porous structure used for the coated textile of the invention is suitable for reflecting sunlight with a wave band of 0.3-2.5 microns and has high emissivity in a wave band of 8-13 microns, so that the radiation refrigerating layer is suitable for emitting heat in an infrared radiation mode through an atmospheric window. The coating textile has the solar light reflectivity of more than or equal to 0.93 and the atmospheric window emissivity of more than 0.95. The radiation refrigeration layer combines inorganic particles and a porous structure, fully utilizes the scattering effect of the radiation refrigeration layer on sunlight, and increases the reflectivity of the sunlight.

Preferably, the inorganic particles have a particle size of 0.5 to 6 μm. More preferably, the inorganic particles have a particle size of 0.5 to 3 μm. More preferably 0.8 to 1.3 μm.

Preferably, the pore diameter of the porous structure is 50 to 2000nm. More preferably 80 to 500nm. More preferably 100 to 200nm.

Preferably, the porosity of the radiation refrigerating layer is 10-40%. More preferably 20 to 35%.

Preferably, the volume of the inorganic particles is 6 to 24% of the volume of the radiation refrigerating layer. More preferably 10 to 21%. Still more preferably 18%.

Preferably, the thickness of the radiation refrigerating layer is 40-200 μm. More preferably 120 to 180 μm.

Preferably, the radiation refrigerating layer material is one or more of polyvinylidene fluoride-hexafluoropropylene copolymer (P (VDF-HFP)), polyvinylidene fluoride (PVDF), polyethylene terephthalate (PET), polyvinyl chloride (PVC), polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA), polylactic acid (PLA), polytetrafluoroethylene (PTFE) and polymethylpentene (TPX). Further preferably, polyvinylidene fluoride-hexafluoropropylene copolymer (P (VDF-HFP)).

Preferably, the substrate is one or more of cotton fabric, nylon fabric, polylactic acid fabric, silk fabric, polyester fabric and polyethylene fabric. Further preferably a polyester fabric (PET fabric).

Preferably, the inorganic particles are one or more of alumina, silica, silicon carbide, silicon nitride, aluminum phosphate, barium sulfate and titanium dioxide. More preferably, alumina (Al) ₂ O ₃ ) Particles. More preferably, the inorganic particles are spherical alumina particles.

The preparation method of any one of the coated textiles with the all-day efficient passive radiation cooling function comprises the following steps:

(1) Adding inorganic particles into an organic solvent, performing ultrasonic dispersion, then adding a radiation refrigeration layer material, and uniformly stirring until the radiation refrigeration layer material is completely dissolved to prepare a dispersion liquid;

(2) Coating the dispersion liquid on the surface of a substrate, and volatilizing an organic solvent to obtain the coated textile;

alternatively, the pore-forming agent is added to the organic solvent while the inorganic particles are added to the organic solvent; and the pore-forming agent and the organic solvent are not the same substance.

When the pore-forming agent is added at the same time, preferably, in the step (1), after the inorganic particles and the pore-forming agent are added, ultrasonic dispersion is carried out for 20-60min, so that the materials are uniformly mixed.

Preferably, in the step (2), the specific operation of applying the dispersion to the surface of the substrate is as follows:

the dispersion was cast on the substrate surface and roll coated using a coater.

Preferably, in the step (1), after the radiation refrigeration layer material is added, stirring is carried out in a water bath at the temperature of 30-50 ℃ for 1-3 h until the radiation refrigeration layer material is completely dissolved.

Preferably, the organic solvent is one or more of acetone, butanone, dichloromethane and trichloromethane. Acetone is more preferred.

Preferably, the pore-forming agent is one or more of water, absolute ethyl alcohol and dichloromethane. More preferably water.

Specifically, the preparation method of the coated textile with the function of high-efficiency passive radiation cooling all day preferably comprises the following steps:

(1) Weighing Al ₂ O ₃ Adding water and acetone into a beaker, and performing ultrasonic dispersion to form uniform dispersion liquid;

(2) Then adding P (VDF-HFP) into the dispersion liquid, stirring in a water bath until the P (VDF-HFP) is completely dissolved in acetone to form uniform and stable coating dispersion liquid;

(3) Then pouring the coating dispersion liquid on the PET fabric, and rolling by using a coating machine; and after the acetone and the water are completely volatilized, the preparation of the composite porous coating fabric (the coating textile with the all-day high-efficiency passive radiation cooling function) is finished.

The invention provides a radiation cooling coating textile with alumina particles and a porous structure and a preparation method thereof, and shows the cooling performance. The coating textile comprises a passive radiation refrigeration layer and a fabric fiber (substrate) two-layer structure, wherein the passive radiation refrigeration layer has high influence on sunlight reflection and mid-infrared emission; the particle size of inorganic particles in the radiation refrigeration layer is optimized, the high reflection of the inorganic particles to sunlight is exerted, and the radiation cooling effect is further improved. Furthermore, the coated textile has good hydrophobicity, which can ensure outdoor durability of cooling performance and impart self-cleaning performance to the coated textile. The preparation process of the coated textile is simple and low in cost. The coated textile and the preparation method thereof successfully prove the application of radiation cooling in the textile and provide another idea for preparing the radiation cooling coated fabric which is low in cost and can be produced in a large area.

Compared with the prior art, the invention has the following beneficial effects:

according to the coated textile with the all-day efficient passive radiation cooling function, the inorganic particles are added in the radiation cooling layer, the porous structure is arranged, the scattering effect of the coated textile on sunlight is fully utilized, the reflectivity of the coated textile on the sunlight is effectively increased, and the radiation cooling effect is further improved. Compared with a pure porous coating fabric or a coating fabric only added with inorganic particles, the coating textile prepared by the invention has higher radiation refrigeration effect. Meanwhile, the coated textile has good hydrophobicity, can ensure outdoor durability of cooling performance and endows the coated textile with self-cleaning performance. The preparation method of the coated textile is simple, the cost is low, and the addition amount of the inorganic particles is small.

Drawings

FIG. 1 is a surface topography characterization SEM image of a # 3 coated textile prepared in example 1;

FIG. 2 is a surface topography characterization SEM image of the 3# coated textile prepared in example 1;

FIG. 3 is a surface topography characterization SEM image of the 6# coated textile prepared in example 2;

FIG. 4 is a surface topography characterization SEM image of the 13# coated textile prepared in example 2;

FIG. 5 is a surface topography characterization SEM image of the 8# coated textile prepared in example 2;

FIG. 6 is a reflectance characterization plot of a # 3 coated textile prepared in example 1;

FIG. 7 is a graph representing the reflectance of the 8# coated textile prepared in example 2;

FIG. 8 is a reflectance characterization plot of the 19# coated textile prepared in example 4;

FIG. 9 is a graph of a comparison of temperature test characterization of # 3 coated textile made in example 1 and PET fabric in comparative example 1;

FIG. 10 is a graphical representation of the aqueous contact angle of the surface of the coated textile # 3 prepared in example 1.

Detailed Description

The present invention is further illustrated by the following specific examples.

Example 1: selection of porosity

(1) 2g of Al having an average particle size of 1.2 μm were weighed ₂ O ₃ Adding water and 24g of acetone into a 50mL beaker, and performing ultrasonic dispersion for 30min to form uniform dispersion liquid;

(2) Then 3g of P (VDF-HFP) is added into the dispersion liquid, and the mixture is magnetically stirred for 2 hours in a water bath at 40 ℃ until the P (VDF-HFP) is completely dissolved in acetone to form uniform and stable coating dispersion liquid;

(3) The coating dispersion was then cast onto PET fabric and roll coated using a lab coater. And after the acetone and the water are completely volatilized, the preparation of the composite porous coating fabric (coating textile) is finished.

In the preparation process, the addition amounts of water are respectively 0.5g, 0.75g, 1g, 1.25g and 1.5g, and finally the prepared composite porous coating fabric is respectively marked as 1#, 2#, 3#, 4#, and 5#; the porosity and corresponding reflectivity and emissivity of the five coated textiles are shown in table 1:

TABLE 1 Performance parameters of five coated textiles prepared in this example

Coated textile	1#	2#	3#	4#	5#
						Porosity/%	20	25	30	35	40
Reflectivity/%)	0.94	0.94	0.95	0.95	0.95
						Emissivity/%)	0.98	0.98	0.98	0.98	0.98

As can be seen from Table 1, as the porosity is increased (i.e. the addition amount of the pore-forming agent water in step 1 is increased), the reflectance of the coated textile is increased first and then reaches stability, and the emissivity is not changed along with the change of the porosity; the porosity of the 3# coating textile is the most preferred porosity, combining the properties and the addition of the pore-forming agent (water).

Morphology characterization SEM of # 3 radiation refrigeration fabric (coated textile) surface as shown in fig. 1 and 2, it can be seen from fig. 1 that the surface of the radiation refrigeration layer has alumina particles with a diameter of about 1.2 microns; as can be seen from fig. 2, the radiation refrigerating layer has a nanoporous structure thereon.

The coating thickness of the radiation refrigeration fabric prepared in the embodiment is 150 μm, and the volume fraction of the aluminum oxide is 18%. The solar light reflectivity of the 3# coating textile is 0.95 (as shown in fig. 6), and the atmospheric window emissivity is 0.98, which indicates that the arrangement of the inorganic particles and the porous structure can effectively improve the radiation refrigeration effect of the radiation refrigeration layer. The pore diameter of the porous structure of the 3# coating textile is 100-200nm.

As shown in fig. 10, the contact angle of the water drop on the surface of the 3# coated textile prepared in this example is 126.4 °, indicating that the coated textile also has good hydrophobicity.

Example 2: selection of average particle size of inorganic particles

(1) 2g of Al are weighed ₂ O ₃ And 24g of acetone, adding the mixture into a 50mL beaker, and performing ultrasonic dispersion for 30min to form a uniform dispersion liquid;

(3) The coating dispersion was then cast onto PET fabric and roll coated using a lab coater. And after the acetone is completely volatilized, the preparation of the composite coating fabric (coating textile) is finished.

According to the above preparation process, al having an average particle diameter of 0.5. Mu.m, 0.8. Mu.m, 1.2. Mu.m, 1.5. Mu.m, 2. Mu.m, 3. Mu.m, 4. Mu.m, 5 μm was used ₂ O ₃ The prepared coating textiles are respectively marked as 6#, 7#, 8#, 9#, 10#, 11#, 12# and 13#; the parameters of each coated textile are shown in table 2:

TABLE 2 Property parameters of the coated textiles prepared in this example

Coated textile	Average particle diameter of alumina/. Mu.m	Reflectivity/%)	Emissivity/%)
				6#	0.5	0.91	0.96
7#	0.8	0.92	0.96
				8#	1.2	0.93	0.96
9#	1.5	0.91	0.96
				10#	2	0.91	0.96
11#	3	0.9	0.96
				12#	4	0.89	0.96
13#	5	0.89	0.96

As can be seen from Table 2, as the average particle size of alumina increases, the reflectance of each coated textile increases and then decreases, and reaches a maximum at an average particle size of 1.2 μm (8 #); the emissivity of each coated textile did not change with the change in average particle size.

The thickness of the coating of the radiation refrigeration fabric (coated textile) prepared in the embodiment is 150 μm, the volume fraction of alumina is 18%, and the porosity is 0%. Surface SEM image of # 8 coated textile as shown in fig. 5, without porous structure on the coating, indicating that it does not have porous structure; the solar reflectance was 0.93 (as shown in fig. 7) and the atmospheric window emissivity was 0.96. Surface SEM images of # 6 and # 13 coated textiles are shown in fig. 3 and 4, respectively, and from fig. 3 it can be seen that the radiation-cooled layer of # 6 coated textile has alumina particles with an average particle size of 0.5 μm; as can be seen in fig. 4, the surface of the radiation refrigeration layer of the 13# coated textile had alumina particles with an average particle size of 5 μm.

From the comparison of the reflectivity of the coated textile # 3 in example 1 and the reflectivity of the coated textile # 8 in this example, the reflectivity 0.95 and the emissivity 0.98 of the coated textile # 3 with the porous structure are both higher than the reflectivity 0.93 and the emissivity 0.96 of the coated textile # 8 without the porous structure, indicating that the porous structure can improve the reflectivity of the coated textile. The preparation of the 3# coated textile in example 1 is the most preferred example.

Example 3: selection of alumina volume fraction in radiant refrigeration layer

(1) Al having an average particle diameter of 1.2 μm was weighed ₂ O ₃ And 24g of acetone, adding the mixture into a 50mL beaker, and performing ultrasonic dispersion for 30min to form a uniform dispersion liquid;

According to the above preparation method, al ₂ O ₃ The addition amounts of the components are respectively set to be 0.5g, 1g, 1.5g, 2g and 2.5g, and the prepared coating textiles are respectively marked as 14#, 15#, 16#, 17# (the same as 8# in the embodiment 2) and 18#; the parameters of each coated textile prepared are shown in table 3:

coated textile	14#	15#	16#	17#	18#
						Alumina/g	0.5	1	1.5	2	2.5
Volume fraction of alumina/%)	6	10	15	18	21
						Reflectivity/%)	0.68	0.78	0.86	0.93	0.93
Emissivity/%)	0.95	0.95	0.96	0.96	0.96

As shown in Table 3, the reflectivity of the prepared coated textile is increased along with the increase of the addition amount (volume fraction) of the aluminum oxide, but when the volume fraction reaches 18%, the reflectivity is not increased any more; taken together, a volume fraction of 18% alumina is the most preferred volume fraction.

Example 4

(1) 2g of Al having an average particle size of 1.2 μm were weighed ₂ O ₃ And 30g of acetone, adding into a 50mL beaker, and carrying out ultrasonic dispersion for 30min to form a uniform dispersion liquid;

(2) Then adding 3g of P (VDF-HFP) into the dispersion, magnetically stirring for 2h in water bath at 40 ℃, and forming uniform and stable coating dispersion after P (VDF-HFP) is completely dissolved in acetone;

(3) The coating dispersion was then cast onto PET fabric and roll coated using a lab coater. And after the acetone is completely volatilized, the preparation of the composite coating fabric (coating textile) is finished, and the coating textile is marked as 19#.

The coating thickness of the radiation refrigeration fabric (coating textile 19 #) prepared by the embodiment is 100 μm, the volume fraction of alumina is 18%, the porosity is 0%, the solar reflectance is 0.81 (as shown in figure 8), and the atmospheric window emissivity is 0.98.

Comparing the 8# coated textile (coating thickness 150 μm, reflectivity 0.93) of example 2 with the 19# coated textile of this example, the coating thickness (100 μm) and reflectivity (0.81) of the 19# coated textile are significantly lower than those of the 8# coated textile; it is stated that the amount of acetone added can affect the final coating thickness, which in turn affects the reflectivity of the product.

Comparative example 1

The surface of the PET fabric was not treated.

As shown in fig. 9, the 3# coated textile resulted in an average temperature cooling of 5.4 ℃ compared to the normal PET fabric (comparative example 3) under daytime solar irradiation; finally, its temperature may be 11.0 ℃ lower than ambient temperature; at night, the cooling device also has sub-ambient temperature cooling of 5.0 ℃ and has excellent passive cooling performance.

The preparation method has the greatest advantage that the prepared coated textile uses the alumina and the pore-forming agent (water) with lower cost, and ultrahigh sunlight reflectivity is obtained. The radiation refrigeration layer makes full use of the scattering effect of inorganic particles (aluminum oxide) and pores (porous structure), increases the reflectivity of sunlight and improves the radiation refrigeration effect.

The embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to the embodiments, and various changes can be made according to the objects of the invention. Any modification, addition, or equivalent substitution made within the scope of the principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A coating textile with an all-day high-efficiency passive radiation cooling function is characterized by comprising a substrate and a radiation refrigerating layer which is arranged on the substrate and has inorganic particles and a porous structure;

the porosity of the radiation refrigeration layer is 0-50%.

2. The coated textile with efficient passive radiative cooling throughout the day of claim 1, wherein the particle size of the inorganic particles is 0.5-6 μm.

3. The coated textile with efficient passive radiative cooling throughout the day of claim 1, wherein the pore size of the porous structure is between 50 and 2000nm.

4. A coated textile product having an all-day high efficiency passive radiant cooling function as claimed in claim 1 wherein said radiant cooling layer has a porosity of 10-40%.

5. The coated textile with high-efficiency passive radiative cooling throughout the day of claim 1, wherein the volume of the inorganic particles is between 6 and 24% of the volume of the radiative cooling layer.

6. A coated textile product with efficient passive radiative cooling throughout the day according to claim 1, wherein the thickness of the radiative cooling layer is between 40 and 200 μm.

7. The coated textile product with all-day high-efficiency passive radiation cooling function according to claim 1, wherein the radiation cooling layer material is one or more of polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinylidene fluoride, polyethylene terephthalate, polyvinyl chloride, polydimethylsiloxane, polymethyl methacrylate, polylactic acid, polytetrafluoroethylene and polymethylpentene.

8. The coated textile with the all-day high-efficiency passive radiation cooling function according to claim 1, wherein the substrate is one or more of cotton fabric, nylon fabric, polylactic acid fabric, silk fabric, polyester fabric and polyethylene fabric;

the inorganic particles are one or more of alumina, silica, silicon carbide, silicon nitride, aluminum phosphate, barium sulfate and titanium dioxide.

9. The method for preparing the coated textile with the function of high-efficiency passive radiation cooling all day long according to any one of claims 1 to 8, which is characterized by comprising the following steps:

(1) Adding inorganic particles into an organic solvent, performing ultrasonic dispersion, adding a radiation refrigerating layer material, and uniformly stirring to prepare a dispersion liquid;

(2) Coating the dispersion liquid on the surface of a substrate, and obtaining the coated textile after the organic solvent is volatilized;

alternatively, the inorganic particles are added to the organic solvent while the pore-forming agent is added to the organic solvent; and the pore-forming agent and the organic solvent are not the same substance.

10. The preparation method according to claim 9, wherein the organic solvent is one or more of acetone, butanone, dichloromethane and chloroform;

the pore-making agent is one or more of water, absolute ethyl alcohol and dichloromethane.