High emissivity selective hydrophobic pastes for clothing dyeing and methods of making the same

Abstract

The application belongs to the field of new material preparation, and particularly relates to a high-emission selective hydrophobic slurry for clothes dyeing and a preparation method thereof, which comprises the following steps: S1. 10-30 parts of tellurium oxide, 20-45 parts of niobium oxide and 10-35 parts of rare earth oxide are weighed, and after being fully mixed, ball milling and powdering are sequentially performed; S2. the obtained precursor powder is subjected to melting and sintering to obtain a molten liquid; S3. after the molten liquid is subjected to quenching, filtration and drying, a coarse powder A is obtained; S4. the coarse powder A is subjected to sand milling to obtain slurry A1, A2 and A3 with different median particle sizes; S5. the slurry A1, A2 and A3 are mixed in proportion, and then subjected to hydrophobic modification to obtain the slurry. The slurry can realize the effects of low absorption in the visible light, near-infrared and 3-8 mu m wave bands and high emission in the 8-14 mu m wave band, and has excellent radiation refrigeration effect.

Description

Technical Field

[0001] This invention belongs to the field of new material preparation, specifically relating to a highly emission-selective hydrophobic slurry for clothing dyeing and its preparation method. Background Technology

[0002] Radiative cooling is a relatively new method for managing clothing thermal energy in recent years. It achieves this by simultaneously giving the fabric surface high solar reflectivity and high atmospheric window emission performance. When people wear this type of clothing, the high solar reflectivity reduces the amount of solar energy incident. Under ideal, dry conditions, the air absorbs almost no thermal radiation in the 8-13 micrometer range, thus achieving efficient heat dissipation. This wavelength range is also known as the atmospheric window band.

[0003] However, in practical applications, especially in hot and humid environments, water molecules in the air have a certain absorption capacity for the entire infrared spectrum, which obviously reduces the radiative cooling effect of the material. Therefore, to ensure material performance, it is necessary to minimize the absorption capacity of the material in wavelengths other than 8-13 micrometers, which will compensate for the loss of radiative cooling effect to some extent. The ratio of the emissivity of a material in the 8-13 micrometer range to its full-spectrum infrared emissivity is called emissivity selectivity. The higher the selectivity, the better the radiative cooling effect of the material, and vice versa.

[0004] To achieve the radiation cooling function on the fabric surface, dyes with radiation cooling properties are required, and the most crucial components of these dyes are the fillers and sizing agents that also possess radiation cooling capabilities. Furthermore, self-cleaning performance is another important function of clothing, and achieving this requires the printed filler surface to have a hydrophobic effect. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a highly emission-selective filler for preparing clothing with radiation cooling and self-cleaning functions, which is suitable for dyeing clothing surfaces.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A method for preparing a highly emission-selective hydrophobic slurry for clothing dyeing includes the following steps:

[0008] S1. Weigh 10-30 parts by weight of tellurium oxide, 20-45 parts by weight of niobium oxide and 10-35 parts by weight of rare earth oxide, mix them thoroughly and then perform ball milling and powdering steps in sequence to obtain precursor powder;

[0009] S2. The precursor powder is melted and sintered to obtain a molten liquid;

[0010] S3. The molten liquid is poured into cold water for quenching, filtered and dried to obtain coarse powder A;

[0011] S4. Ethanol is added to the coarse powder A to prepare a mixture, and a dispersant is added to the mixture before sand milling to obtain slurries A1, A2, and A3 with different median particle sizes.

[0012] S5. Mix the slurries A1, A2 and A3 in proportion, add the modifying agent, and reflux at 40°C for 20-25 hours to obtain the slurry.

[0013] Furthermore, the rare earth oxides include cerium oxide and / or lanthanum oxide.

[0014] Furthermore, in step S1, the ball milling is carried out using a planetary ball mill with a rotation speed of 400 r / min, a ball mill ball ratio of large, medium and small balls of 3:4:3, a ball mill chamber air, liquid and ball volume ratio of 1:1:1, and a ball milling time of 12 h.

[0015] Furthermore, in step S2, the melting and sintering process includes five stages, specifically:

[0016] The first stage involves uniformly raising the temperature from 50℃ to 400℃ over a period of 35 minutes.

[0017] The second stage involves maintaining the temperature at 400℃ for 30 minutes.

[0018] The third stage involves uniformly raising the temperature from 400℃ to 900℃ over a period of 60 minutes.

[0019] The fourth stage involves uniformly raising the temperature from 900℃ to 1400℃ over a period of 120 minutes.

[0020] The fifth step involves maintaining the temperature at 1400℃ for 240 minutes.

[0021] Furthermore, during the fifth stage of the process, after holding the liquid at a temperature of 180 min, the liquid is stirred at a speed of 60 r / min for 30 min, and then the temperature is held until the sintering is completed.

[0022] Furthermore, in step S4, the content of the coarse powder A in the mixture is 40%;

[0023] And / or, in step S4, the dispersant is selected as BYK111 type dispersant, and the amount of the dispersant added is 10-13% of the mass of the mixture.

[0024] Furthermore, in step S4, the median particle sizes of the slurries A1, A2, and A3 are 15-25 μm, 5-10 μm, and 0.3-0.7 μm, respectively.

[0025] Furthermore, in step S5, the mixing ratio of slurries A1, A2, and A3 is 1:0.8-1.3:0.4-0.6 by mass.

[0026] And / or, in step S5, the modifying agent includes heptadecafluorodecyltrimethoxysilane;

[0027] And / or, in step S5, the mass ratio of the modified additive to the mixed slurry is 4-6:100.

[0028] The present invention also provides a highly emission-selective hydrophobic slurry for clothing dyeing obtained by the above preparation method.

[0029] The present invention also provides the application of the above-mentioned highly emission selective, hydrophobic slurry in the field of clothing.

[0030] In existing technologies, titanium dioxide is the most commonly used infrared reflective filler. However, the quality of the filler is affected by the content of rutile crystals, and high-purity rutile titanium dioxide is very expensive. Therefore, using amorphous materials as fillers can completely avoid the influence of crystal purity on material properties, giving it a greater advantage in industrial production.

[0031] The essence of filler reflecting infrared radiation is Mie scattering with incident light. Generally, large-particle fillers have a better reflection effect on infrared radiation with longer wavelengths, while small-particle fillers have a better reflection effect on incident light with shorter wavelengths. In existing technologies, the fillers used are often processed using uniform ball milling or sand milling processes. The resulting slurry has a uniform particle size, which has a good reflection effect on incident light of a specific wavelength, but poor reflection performance across the entire solar spectrum.

[0032] The beneficial effects of this invention are:

[0033] 1. The near-infrared reflectivity of fillers depends on their refractive index and light absorption rate. High-emission near-infrared reflective materials require high refractive index and low absorption rate. Tellurium-niobium type glass has high transmittance in the visible and infrared bands and is often used to prepare nonlinear optoelectronic devices; while lanthanum-niobium glass formed with rare earth materials such as lanthanum and cerium has a high refractive index. Based on this, this invention modifies tellurium-niobium type glass with rare earth materials, which can simultaneously exert the material's high refractive index and low absorption performance, thereby giving the material high near-infrared reflectivity. In addition, tellurium-niobium type glass has low absorption efficiency in the near-infrared and 3-8μm bands, while oxides formed with rare earth materials also have low absorption rates in the 3-8μm band. Therefore, after modifying tellurium-niobium type glass with rare earth materials, it is possible to achieve low absorption in the visible, near-infrared, and 3-8μm bands, and high emission in the 8-14μm band, that is, to achieve high selectivity.

[0034] 2. In the production process of this invention, through process control, the powder material is first processed into intermediate raw materials with a certain particle size, and then the powders of various particle size distributions are proportioned according to a certain content to finally obtain a filler product with multiple particle size distributions. This filler can produce excellent reflection effect on sunlight across the entire wavelength range.

[0035] 3. In the final production process of the filler slurry, the surface of the filler is hydrophobically modified by using heptadecafluorodecyltrimethoxysilane. When this filler is used to formulate printing dyes for screen printing, it can make the clothing exhibit superhydrophobic and self-cleaning effects. Attached Figure Description

[0036] Figure 1 The XRD test results are for coarse powder A in Example 1;

[0037] Figure 2 The results of the reflectivity test of the slurry in Example 1 are as follows;

[0038] Figure 3 This is a comparison of the surface temperature of the fabric before and after coating with the slurry prepared in Example 1. Detailed Implementation

[0039] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings, but the scope of protection of the present invention is not limited to the following description.

[0040] Example 1

[0041] A method for preparing a highly emission-selective hydrophobic slurry for clothing dyeing includes the following steps:

[0042] S1. Weigh out 15 parts by weight of tellurium oxide, 26 parts by weight of niobium oxide, and 16 parts by weight of lanthanum oxide. Mix them thoroughly and add a certain amount of water. Wet the mixture in a planetary ball mill at a speed of 400 r / min. The ratio of large, medium, and small balls is 3:4:3. The volume ratio of air, liquid, and balls in the mill chamber is controlled at 1:1:1. The grinding time is 12 h. After grinding, filter the grinding beads through a 40-mesh sieve to obtain a coarse slurry. Dry the coarse slurry thoroughly in a 90℃ oven to obtain a precursor sample that has agglomerated into lumps. Put the lumpy precursor sample back into a powder crusher to grind it into powder to obtain a uniformly mixed precursor powder.

[0043] S2. The precursor powder is loaded into an alumina crucible and heated in a melting furnace equipped with a stirring paddle. The heating procedure is as follows: First stage, heating from 50°C to 400°C for 35 minutes; Second stage, maintaining a constant temperature of 400°C for 30 minutes; Third stage, heating from 400°C to 900°C for 1 hour; Fourth stage, heating from 900°C to 1400°C for 2 hours; Fifth stage, maintaining a constant temperature of 1400°C for 4 hours; then the procedure is terminated. During the fifth stage of holding for 3 hours, the alumina stirring paddle is lowered into the molten material and slowly stirred at 60 revolutions per minute for 30 minutes, then the stirring paddle is lifted. After the heating procedure is completed, a molten liquid is obtained.

[0044] S3. The molten liquid is poured into cold water for quenching, filtered and dried to obtain coarse powder A;

[0045] S4. Ethanol is added to the coarse powder A to prepare a mixture, so that the content of coarse powder A in the mixture is 40%. 12% by mass of BYK111 type dispersant is added to the mixture, and then it is placed in a sand mill for sand milling. The grinding ball particle size is 0.5 mm. The particle size of the slurry is measured with a laser particle size analyzer every 15 minutes to obtain slurry A1 with D50 of 21 μm, slurry A2 with D50 of 6.2 μm, and slurry A3 with D50 of 0.45 μm, respectively.

[0046] S5. Mix the slurry A1, slurry A2 and slurry A3 in a mass ratio of 1:1:0.5, add 5% by mass of heptadecafluorodecyltrimethoxysilane to the mixture, and reflux at 40°C for 24 hours to obtain the slurry.

[0047] Performance testing:

[0048] The coarse powder A was subjected to XRD testing, and the test results are as follows: Figure 1 As shown in the figure, within the scanning angle range, the intensity of the scattered X-rays changes gradually without independent spikes, indicating that the coarse powder A is an amorphous material.

[0049] For reflective properties, the slurry needs to be prepared into a coating sample for testing. The specific procedure is as follows: Take 30 parts of the above slurry, 5 parts of dispersant (DM-1501) from Shanghai ANOKY Co., Ltd., 30 parts of waterborne polyurethane resin, 5 parts of nonionic formaldehyde-free crosslinking agent (DM-8926) from Shanghai ANOKY Co., Ltd., 2 parts of fastness modifier (DM-2582N) from Shanghai ANOKY Co., Ltd., 2 parts of general-purpose leveling agent, 1 part of defoamer, and 25 parts of water. Mix them evenly to obtain the finished white coating. Apply the coating to the surface of artificial cotton fabric using screen printing, with a thickness of 35 μm and a screen mesh of 330 mesh, to obtain a hydrophobic fabric.

[0050] The reflectivity of the fabric was tested using a UV-Vis-IR spectrophotometer, and the results are as follows: Figure 2 As shown, the coating achieves a reflectivity of up to 92% (average). Comparing the changes in fabric surface temperature before and after coating, [the following text appears to be incomplete and requires further context: "attached..."] Figure 3 This is a comparison of the surface temperature of the fabric before and after coating with the slurry prepared in Example 1.

[0051] The emissivity of the slurry was tested using an IR-1 hemispherical emissivity meter, following the testing method specified in GB / T25261—2018 "Reflective Thermal Insulation Coatings for Buildings". At 25℃, the emissivity was measured to be 0.96 in the 8-13 μm window band and 0.8 in the 2.5-25 μm band. Calculations showed an emissivity selectivity as high as 1.2 (0.96 / 0.8), indicating that the material's high emissivity is concentrated in the atmospheric window band, with lower emissivity in non-window bands, demonstrating good radiative cooling properties.

[0052] Example 2

[0053] A method for preparing a rare-earth functional pigment paste for clothing dyeing includes the following steps:

[0054] S1. By weight, prepare 25 parts tellurium oxide, 36 parts niobium oxide, and 20 parts cerium oxide. After thorough mixing, add a certain amount of water and wet-mill in a planetary ball mill. The ball mill speed is 400 r / min, the ratio of large, medium, and small balls is 3:4:3, and the volume ratio of air:liquid:balls in the chamber is controlled at 1:1:1. The grinding time is 12 hours. After grinding, filter the grinding beads through a 40-mesh sieve to obtain a coarse grinding slurry. Dry the coarse grinding slurry thoroughly in a 90℃ oven to obtain a precursor sample that has agglomerated into lumps. Put the blocky precursor sample back into a powder crusher for grinding to obtain a uniformly mixed precursor powder.

[0055] S2. The precursor powder is loaded into an alumina crucible and heated in a melting furnace equipped with a stirring paddle. The heating procedure is as follows: first, heating from 50°C to 400°C for 35 minutes; second, maintaining a constant temperature of 400°C for 30 minutes; third, heating from 400°C to 900°C for 1 hour; fourth, heating from 900°C to 1400°C for 2 hours; fifth, maintaining a constant temperature of 1400°C for 4 hours; then the procedure is terminated. During the fifth stage of holding for 3 hours, the alumina stirring paddle is lowered into the molten material and slowly stirred at 60 revolutions per minute for 30 minutes, after which the stirring paddle is lifted. After the heating procedure is completed, a molten liquid is obtained.

[0056] S3. The molten liquid is poured into cold water for quenching, filtered and dried to obtain coarse powder A;

[0057] S4. Ethanol is added to the coarse powder A to prepare a mixture, so that the content of coarse powder A in the mixture is 40%. 14% by weight of BYK111 type dispersant is added to the mixture, and then it is placed in a sand mill for sand milling. The grinding ball particle size is 0.5 mm. The particle size of the slurry is measured with a laser particle size analyzer every 15 minutes to obtain slurry A1 with D50 of 20 μm, slurry A2 with D50 of 8 μm, and slurry A3 with D50 of 0.7 μm, respectively.

[0058] S5. Mix the slurry A1, slurry A2 and slurry A3 in a mass ratio of 1:0.8:0.6, add 6% by mass of heptadecafluorodecyltrimethoxysilane to the mixed slurry, and reflux at 40°C for 24 hours to obtain the colored paint slurry.

[0059] Comparative Example 1

[0060] A highly emission-selective hydrophobic slurry for clothing dyeing is provided. The difference between this slurry and that of Example 1 is that the finished slurry has a uniform particle size. Specifically, in step S4, powder A is uniformly milled to obtain a finished slurry with a D50 of 5 μm; the remaining steps are the same.

[0061] Comparative Example 2

[0062] A highly emission-selective hydrophobic slurry for clothing dyeing is provided. The preparation method differs from Example 1 in that the components of Comparative Example 2 do not contain rare earth oxides. Specifically, in step S1, 25 parts of tellurium oxide and 36 parts of niobium oxide are directly mixed before proceeding to other steps.

[0063] Comparative Example 3

[0064] Rutile titanium dioxide with a median particle size of 5-6 μm was purchased from Shanghai Yuejiang.

[0065] The reflectivity and emissivity of Example 2 and Comparative Examples 1-4 were tested using the same method, and their emissivity selectivity and average cooling were calculated.

[0066] The results are shown in Table 1 below (average).

[0067] Table 1

[0068]

[0069]

[0070] Comparative Example 4

[0071] In Comparative Example 4, the modifying agent heptadecafluorodecyltrimethoxysilane in Example 1 was replaced with commercially available ACUSOL 880 hydrophobic modifier, while the other steps remained unchanged.

[0072] Comparative Example 5

[0073] In Comparative Example 4, the modifying agent heptadecafluorodecyltrimethoxysilane in Example 1 was replaced with hexamethyldisilazane, while the other steps remained unchanged.

[0074] Hydrophobicity test:

[0075] Following the same method, the slurries from Comparative Examples 4 and 5 were prepared into coatings and applied to the surface of artificial cotton fabric. Water droplets were then placed on the coatings, and the surface contact angle of the water droplets was measured using a water contact angle tester. A larger surface contact angle indicates better hydrophobicity. The results are shown in Table 2 below.

[0076] Table 2

[0077] Surface contact angle 146° 145° 130° 138°

[0078] As shown in Table 2, for the slurry of the present invention, the hydrophobic modification effect of heptadecafluorodecyltrimethoxysilane is better than that of general modifiers.

[0079] Slurry stability test:

[0080] Example 3

[0081] The molten liquid obtained after steps S1 and S2 in Example 1 was poured while hot onto the surface of a horizontally placed stainless steel plate and allowed to cool naturally in the air to obtain a solid.

[0082] Comparative Example 6

[0083] Weigh out 40 parts by weight of tellurium oxide, 15 parts by weight of niobium oxide, and 40 parts by weight of lanthanum oxide, and perform steps S1 and S2 in Example 1. Pour the resulting molten liquid onto the surface of a horizontally placed stainless steel plate while it is still hot, and allow it to cool naturally in the air to obtain a solid.

[0084] The difference between Comparative Example 6 and Example 3 is that the proportions of the raw materials used to prepare the slurry are different.

[0085] Comparative Example 7

[0086] Weigh out 15 parts of tellurium oxide, 26 parts of gallium oxide, and 16 parts of lanthanum oxide, and perform steps S1 and S2 in Example 1. Pour the resulting molten liquid onto the surface of a horizontally placed stainless steel plate while it is still hot, and allow it to cool naturally in the air to obtain a solid.

[0087] The difference between Comparative Example 7 and Example 3 is that the raw material niobium oxide is replaced with gallium oxide.

[0088] Comparative Example 8

[0089] Weigh out 15 parts tellurium oxide, 26 parts niobium oxide, and 16 parts lanthanum oxide, and proceed with step S1 of Example 1. The obtained precursor powder is placed in an alumina crucible, and the temperature is raised from 50°C to 1500°C over 4 hours. The temperature is then maintained at 1500°C for 4 hours to obtain a molten liquid. While still hot, the molten liquid is poured onto the surface of a horizontally placed stainless steel plate and allowed to cool naturally in air to obtain a solid.

[0090] The difference between Comparative Example 8 and Example 3 is the sintering procedure.

[0091] The morphology of the samples obtained in Example 3 and Comparative Examples 6-8 was observed, and the refractive index of the samples was tested using an elliptic polarization spectrometer. The results are shown in Table 3.

[0092]

[0093] As shown in Table 3, whether the slurry of the present invention can form a uniform and stable glass body is closely related to the ratio of each raw material, the type of metal oxide, or the sintering process.

[0094] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A method for preparing a highly emission-selective hydrophobic slurry for clothing dyeing, characterized in that, Includes the following steps: S1. Weigh 10-30 parts of tellurium oxide, 20-45 parts of niobium oxide and 10-35 parts of rare earth oxide by weight, mix them thoroughly and then perform ball milling and powdering steps in sequence to obtain precursor powder; S2. The precursor powder is melted and sintered to obtain a molten liquid; The melting and sintering process includes five stages, specifically: The first stage involves uniformly raising the temperature from 50℃ to 400℃ over a period of 35 minutes. The second stage involves maintaining the temperature at 400℃ for 30 minutes. The third stage involves uniformly raising the temperature from 400℃ to 900℃ over a period of 60 minutes. The fourth stage involves uniformly raising the temperature from 900℃ to 1400℃ over a period of 120 minutes. The fifth stage involves holding the temperature at 1400℃ for 240 minutes. S3. The molten liquid is poured into cold water for quenching, filtered and dried to obtain coarse powder A; S4. Ethanol is added to the coarse powder A to prepare a mixture, and a dispersant is added to the mixture before sand milling to obtain slurries A1, A2, and A3 with different median particle sizes. The median particle sizes of the slurries A1, A2, and A3 are 15–25 μm, 5–10 μm, and 0.3–0.7 μm, respectively. S5. Mix the slurries A1, A2 and A3 in a mass ratio of 1:0.8~1.3:0.4~0.6, add the modifying agent, and reflux at 40°C for 20~25 h to obtain the slurry.

2. The method for preparing a highly emission-selective hydrophobic slurry for clothing dyeing according to claim 1, characterized in that, The rare earth oxides include cerium oxide and / or lanthanum oxide.

3. The method for preparing a highly emission-selective hydrophobic slurry for clothing dyeing according to claim 1, characterized in that, In step S1, the ball milling is carried out using a planetary ball mill with a rotation speed of 400 r / min, a ball mill ball ratio of large, medium and small balls of 3:4:3, a ball mill chamber air, liquid material and ball volume ratio of 1:1:1, and a ball milling time of 12 h.

4. The method for preparing a highly emission-selective hydrophobic slurry for clothing dyeing according to claim 1, characterized in that, When performing the fifth stage of the procedure, after holding the temperature for 180 min, the liquid is stirred at a speed of 60 r / min for 30 min, and then the temperature is held until the sintering is completed.

5. The method for preparing a highly emission-selective hydrophobic slurry for clothing dyeing according to claim 1, characterized in that, In step S4, the content of coarse powder A in the mixture is 40%; And / or, in step S4, the dispersant is selected as BYK111 type dispersant, and the amount of the dispersant added is 10~13% of the mass of the mixture.

6. The method for preparing a highly emission-selective hydrophobic slurry for clothing dyeing according to claim 1, characterized in that, In step S5, the modifying agent includes heptadecafluorodecyltrimethoxysilane; And / or, in step S5, the mass ratio of the modified additive to the mixed slurry is 4~6:

100.

7. A highly emission-selective hydrophobic slurry for clothing dyeing obtained by the preparation method according to any one of claims 1 to 6.

8. The application of the highly emission-selective hydrophobic slurry according to claim 7 in the field of clothing.

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