CN115323801B

CN115323801B - Coated textile with all-day efficient passive radiation cooling function and preparation method thereof

Info

Publication number: CN115323801B
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: 2024-04-30
Anticipated expiration: 2042-09-15
Also published as: CN115323801A

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 coated fabric or a coated fabric added with inorganic particles, the coated fabric prepared by the method has higher radiation refrigeration effect. Meanwhile, the coated textile has good hydrophobicity, can ensure the 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 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

Each year, the energy used for cooling is consumed at a rate of about 52.3EJ, accounting for about 14.6% of the global energy demand. The ever-increasing power consumption increases the 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 heat radiation emitted by the ground to penetrate through the middle infrared atmospheric window (the wavelength is about 8-13 mu m), thereby achieving the cooling effect. The atmospheric window is a dynamic behavior of the earth's atmosphere that allows 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 ambient temperature through radiation heat exchange with the outer space. Compared with the traditional cooling technology, the radiation cooling technology is more and more widely focused and studied as a passive cooling technology without energy consumption and greenhouse gas emission.

The radiation cooling fabric is prepared in two main modes, 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 high 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 radiation cooling performance can be obtained through the design of the coating composition and the structure. However, the coating technology currently faces a plurality of problems of improved cooling effect, complex preparation process, high cost and the like, and greatly limits the wide application of the radiation cooling technology in the textile field.

Disclosure of Invention

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

A coated textile with a full-day efficient 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 refrigeration layer is 0-50%.

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

The radiation refrigerating layer with inorganic particles and porous structure used for the coated textile is suitable for reflecting sunlight with the wave band of 0.3-2.5 mu m and has high emissivity in the wave band of 8-13 mu m, so that the radiation refrigerating layer is suitable for emitting heat in an infrared radiation mode through an atmospheric window. The solar reflectance of the coated textile is greater than or equal to 0.93, and the atmospheric window emissivity is greater 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 particle diameter of the inorganic particles is 0.5 to 6. Mu.m. More preferably, the inorganic particles have a particle diameter of 0.5 to 3. Mu.m. More preferably 0.8 to 1.3. Mu.m.

Preferably, the pore diameter of the porous structure is 50 to 2000nm. Further preferably 80 to 500nm. Still more preferably 100-200nm.

Preferably, the porosity of the radiation refrigeration 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 refrigeration layer. More preferably 10 to 21%. Still more preferably 18%.

Preferably, the thickness of the radiation refrigeration layer is 40-200 μm. Further preferably 120 to 180. Mu.m.

Preferably, the radiation refrigeration 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). More 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 preferred is 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. Further preferred are alumina (Al ₂O₃) particles. As still further preferred, the inorganic particles are spherical alumina particles.

The preparation method of the coated textile with the all-day efficient passive radiation cooling function, which is characterized by comprising the following steps:

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

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

optionally, adding a pore-forming agent to the organic solvent while adding inorganic particles 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, the mixture is dispersed for 20 to 60 minutes by ultrasonic, 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 poured onto 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 for 1-3 hours in a water bath at 30-50 ℃ until the radiation refrigeration layer material is completely dissolved.

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

Preferably, the pore-forming agent is one or more of water, absolute ethyl alcohol and methylene dichloride. Further preferably water.

As a specific preference, a method for preparing a coated textile with an all-day efficient passive radiation cooling function comprises the following steps:

(1) Weighing Al ₂O₃, water and acetone, adding into a beaker, and performing ultrasonic dispersion to form uniform dispersion;

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

(3) Casting the coating dispersion liquid on PET fabric, and roll-coating by using a coater; after the acetone and water are completely volatilized, the preparation of the composite porous coated fabric (coated textile with the full-day efficient passive radiation cooling function) is completed.

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

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

According to the coated textile with the all-day efficient passive radiation cooling function, the inorganic particles are added into the radiation refrigerating layer, and the porous structure is arranged, so that the scattering effect of the coated textile on sunlight is fully utilized, the reflectivity of sunlight is effectively increased, and the radiation refrigerating effect is further improved. Compared with a pure porous coated fabric or a coated fabric added with inorganic particles, the coated fabric prepared by the method has higher radiation refrigeration effect. Meanwhile, the coated textile has good hydrophobicity, can ensure the 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 inorganic particles is small.

Drawings

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

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

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

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

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

FIG. 6 is a graph characterizing the reflectance of the 3# coated textile prepared in example 1;

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

FIG. 8 is a graph representing reflectance profiles of the 19# coated textile prepared in example 4;

FIG. 9 is a graph depicting a comparison of temperature test characterizations of the 3# coated textile produced in example 1 and the PET fabric in comparative example 1;

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

Detailed Description

The invention will be further illustrated with reference to specific examples.

Example 1: selection of porosity

(1) 2G of Al ₂O₃ with the average particle size of 1.2 mu m, water and 24g of acetone are weighed, added into a 50mL beaker, and subjected to ultrasonic dispersion for 30min to form a uniform dispersion;

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

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

In the preparation process, the addition amount of water is 0.5g, 0.75g, 1g, 1.25g and 1.5g respectively, and the finally prepared composite porous coated fabric is respectively marked as No.1, no. 2, no. 3, no. 4 and No. 5. The porosities and the corresponding reflectances and emittances 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 increases (i.e., the amount of pore-forming agent added in step 1 increases), the reflectance of the coated textile increases and then stabilizes, while the emissivity does not change with the change in porosity; the porosity of the 3# coated textile is the most preferred porosity, with the combination of properties and the amount of pore former (water) added.

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

The thickness of the coating of the radiation refrigeration fabric prepared in the embodiment is 150 mu m, and the volume fractions of aluminum oxide are 18%. The solar reflectance of the 3# coated textile is 0.95 (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 refrigerating effect of the radiation refrigerating layer. The pore diameter of the porous structure of the 3# coated textile is 100-200 nm.

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

Example 2: selection of the average particle size of the inorganic particles

(1) Weighing 2g of Al ₂O₃ and 24g of acetone, adding into a 50mL beaker, and performing ultrasonic dispersion for 30min to form a uniform dispersion;

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

According to the preparation process, al ₂O₃ with average grain diameters 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 and 5 mu m is used, and the prepared coated textiles are respectively marked as No. 6, no. 7, no. 8, no. 9, no. 10, no. 11, no. 12 and No. 13; the parameters of each coated textile are shown in table 2:

table 2 performance 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 the 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 does not change with the average particle size.

The radiation refrigeration fabrics (coated textiles) prepared in this example all had a coating thickness of 150 μm, an alumina volume fraction of 18% and a porosity of 0%. The SEM image of the surface of the 8# coated textile is shown in fig. 5, with no porous structure on the coating, indicating that it has no porous structure; solar reflectance was 0.93 (as shown in fig. 7), and atmospheric window emissivity was 0.96. As can be seen from fig. 3, the radiation refrigeration layer of the 6# coated textile has alumina particles with an average particle size of 0.5 μm on the radiation refrigeration layer, as shown in fig. 3 and 4 for the surface SEM images of the 6# and 13# coated textiles, respectively; as can be seen from fig. 4, the surface of the radiant refrigeration layer of the 13# coated textile has alumina particles with an average particle size of 5 μm.

As can be seen from the comparison of the reflectivity of the coated textile of 3# in example 1 and the coated textile of 8# in this example, the reflectivity 0.95 and the emissivity 0.98 of the coated textile of 3# having a porous structure are both higher than the reflectivity 0.93 and the emissivity 0.96 of the coated textile of 8# not having a porous structure, indicating that the porous structure can enhance the reflectivity of the coated textile. The preparation of the 3# coated textile in example 1 is the best example.

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

(1) Al ₂O₃ with the average particle size of 1.2 mu m and 24g of acetone are weighed, added into a 50mL beaker, and subjected to ultrasonic dispersion for 30min to form uniform dispersion;

According to the preparation method, the addition amounts of Al ₂O₃ are respectively set to be 0.5g, 1g, 1.5g, 2g and 2.5g, and the prepared coated textiles are respectively marked as No. 14, no. 15, no. 16 and No. 17 (the same as No. 8 in the example 2) and No. 18; the parameters of each prepared coated textile are shown in table 3:

Coated textile	14#	15#	16#	17#	18#
						Alumina/g	0.5	1	1.5	2	2.5
Alumina volume fraction/%	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 can be seen from table 3, as the amount of alumina added (volume fraction) increases, the reflectivity of the resulting coated textile also increases, but when the volume fraction reaches 18%, the reflectivity no longer increases; considering together, a volume fraction of alumina of 18% is the most preferred volume fraction.

Example 4

(1) 2G of Al ₂O₃ with the average particle size of 1.2 mu m and 30g of acetone are weighed, added into a 50mL beaker, and subjected to ultrasonic dispersion for 30min to form uniform dispersion;

(3) The coating dispersion was then cast onto PET fabric and roll coated using a laboratory coater. After complete evaporation of the acetone, the preparation of the composite coated fabric (coated textile) was completed, which coated textile was designated 19#.

The radiant refrigerant fabric (coated textile 19 #) prepared in this example had a coating thickness of 100 μm, an alumina volume fraction of 18%, a porosity of 0%, a solar reflectance of 0.81 (as shown in fig. 8) and an atmospheric window emissivity of 0.98.

Comparing the 8# coated textile of example 2 (coating thickness of 150 μm, reflectivity of 0.93) with the 19# coated textile of this example, it is seen that both the coating thickness (100 μm) and the reflectivity (0.81) of the 19# coated textile are significantly lower than the coating thickness and the reflectivity 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 is not treated.

As shown in fig. 9, under daytime sun light irradiation, the 3# coated textile caused an average temperature cooling of 5.4 ℃ compared to the normal PET fabric (comparative example 3); 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 excellent passive cooling performance.

The invention has the greatest advantage that the prepared coated textile uses aluminum oxide and pore-forming agent (water) with lower cost, and obtains ultra-high solar reflectance. The radiation refrigerating layer fully utilizes the scattering effect of inorganic particles (alumina) and pores (porous structure), increases the reflectivity of sunlight and improves the radiation refrigerating 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 above embodiments, and various changes can be made according to the objects of the invention. Any modifications, additions, and equivalent substitutions made within the principle of the invention should be included in the protection scope of the invention.

Claims

1. The coated textile with the full-day efficient 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 refrigerating layer is 20-35%;

The volume of the inorganic particles is 18-21% of the volume of the radiation refrigerating layer;

the particle size of the inorganic particles is 0.8-1.3 mu m;

the pore diameter of the porous structure is 100-200nm;

The thickness of the radiation refrigerating layer is 120-180 mu m;

The radiation refrigerating 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;

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.

2. The method for preparing a coated textile with an all-day efficient passive radiation cooling function according to claim 1, comprising the following steps:

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

adding inorganic particles into an organic solvent, and simultaneously adding a pore-forming agent into the organic solvent; and the pore-forming agent and the organic solvent are not the same substance.

3. The preparation method according to claim 2, wherein the organic solvent is one or more of acetone, butanone, dichloromethane, and chloroform;

the pore-forming agent is one or more of water, absolute ethyl alcohol and methylene dichloride.