CN115851040A - A kind of double-layer radiation cooling hydrophobic coating material and its preparation method and application - Google Patents

Abstract

The invention relates to the technical field of radiation refrigeration, and provides a double-layer radiation refrigeration hydrophobic coating material and a preparation method and application thereof. The double-layer radiation refrigeration hydrophobic coating material comprises a radiation bottom coating and a reflection top coating, wherein the radiation bottom coating comprises SiO ₂ And a polymer solution; the reflective top coating comprises hydrophobically modified TiO ₂ Powder and polymer solution, the hydrophobically modified TiO ₂ Treating TiO powder with silane modifier ₂ Thus obtaining the compound. The double-layer radiation refrigeration hydrophobic coating material provided by the invention is simple and easy to prepare, and can be applied to the fields of textiles, building energy-saving materials, solar photoelectric and photo-thermal systems and the like.

Description

A kind of double-layer radiation cooling hydrophobic coating material and its preparation method and application

technical field

The invention relates to the technical field of radiation refrigeration, in particular to a double-layer radiation refrigeration hydrophobic coating material and its preparation method and application.

Background technique

In recent years, global warming has increased people's demand for cooling and cooling. As a result, the energy shortage has intensified. Among them, the electricity consumption of air-conditioning in residential buildings and commercial places in the world has reached 1932 TWh. As a common energy-input cooling method, air-conditioning accounts for more than 50% of building energy consumption and emits 10% of greenhouse gases. Further exacerbated energy shortages and global warming, resulting in a vicious circle. According to a survey, it is estimated that by 2050, the demand for cooling equipment will be 10 times that of the present. In this regard, in order to reduce carbon emissions and achieve the strategic goal of global carbon neutrality in 2060, people have been working hard to explore new and greener thermal management methods.

Radiative refrigeration technology has the advantages of no power input, zero pollution, reliability and stability, etc. It can be widely used in building energy saving, new textile research and development, solar photoelectric thermal system and other fields. It is the most promising method to replace electric cooling. have significant economic benefits. Studies in recent years have shown that infrared radiation coatings can reduce energy consumption of residential buildings by 12-53%, office buildings by 5-28%, and public buildings by 7-17%. Therefore, radiative refrigeration technology is expected to become a new green refrigeration method to replace traditional air-conditioning refrigeration, and alleviate the increasingly severe global warming and energy shortage.

Titanium dioxide (TiO ₂ ) and silicon dioxide (SiO ₂ ) have the advantages of high infrared emissivity and low solar light absorption, cheap price, stable physical and chemical properties, no harmful elements such as chlorine and fluorine, and no VOC volatilization. The team of Shen Weidong of Zhejiang University (CN110274326A) discloses a multilayer daytime radiation cooling coating, the middle layer is composed of low refractive index TiO ₂ layers and high refractive index SiO ₂ layers alternately, the top layer is magnesium fluoride, the structure is complex, and the fabrication The process is cumbersome and hinders large-scale production. Hua Bao et al. (Solar Energy Materials168, 2017, 78-84) designed and prepared a simple double-layer radiative cooling coating with TiO ₂ as the top layer and SiO ₂ as the bottom layer. It can be lowered by 5°C in between. However, this type of material is greatly affected by the ambient humidity, and it is difficult to exert its theoretical radiative cooling effect in a humid environment. Zhang Weidong et al. (CN113278331 A) designed and prepared a self-cleaning passive radiative cooling coating, which uses styrene-acrylic emulsion as a super-hydrophobic self-cleaning topcoat and passive radiative cooling coating as a primer, which has excellent self-cleaning ability. However, the presence of the topcoat masks the solar reflection efficiency of the primer, resulting in poor passive radiative cooling. In addition, the above work only studies the radiative cooling effect of the material on the aluminum substrate, which lacks versatility and limits the large-scale application of the material. Therefore, there are still challenges to obtain efficient, stable and mass-producible radiative cooling materials with a wide range of applications.

Contents of the invention

Aiming at the above shortcomings and deficiencies of the prior art, the present invention aims to provide an efficient, stable and mass-producible double-layer radiation cooling hydrophobic coating material and its preparation method and application.

The invention provides a double-layer radiative refrigeration hydrophobic coating material, comprising a radiation primer and a reflective top coat, wherein:

The radiation primer comprises _SiO2 and a polymer solution;

The reflective top coat includes hydrophobic modified TiO ₂ powder and polymer solution, and the hydrophobic modified TiO ₂ powder is obtained by treating TiO ₂ with a silane modifier.

Preferably, the particle size of the SiO ₂ is 0.5 μm-10 μm, and the particle size of the TiO ₂ is 0.5-10 μm.

Preferably, the polymer solution comprises polyethylene glycol solution, acrylic acid solution or cellulose solution; and/or

The silane modifier includes hexadecyltrimethoxysilane HDTMS, octyltrimethoxysilane MSDS, methyltrimethoxysilane MTMS.

Preferably, the SiO ₂ and the polymer solution are used in an amount ratio of 1-100g/100mL, and/or

The amount ratio of the hydrophobically modified _TiO2 powder to the polymer solution is 1-100g/100mL, and/or

The mass concentration of the polymer solution is 20%-50%, and/or

The mass ratio of the silane modifier to TiO ₂ is 0.2-10:1.

The present invention also provides a method for preparing a double-layer radiation refrigeration hydrophobic coating material, comprising the following steps:

S1, preparation of hydrophobically modified _TiO2 powder:

Dissolving _TiO2 in absolute ethanol to prepare a _TiO2 alcoholysis solution; dissolving the silane modifier in absolute ethanol to obtain a hydrophobic modifier alcoholysis solution;

Mix the _TiO2 alcoholysis solution with the hydrophobic modifier alcoholysis solution, adjust the pH value to be neutral to weakly alkaline, and stir the reaction at a certain temperature;

After the reaction finishes, the mixed solution is centrifuged and dried to obtain hydrophobically modified _TiO2 powder;

S2, preparation of radiation primer: _SiO2 and polymer solution are mixed and stirred to obtain a uniform suspension Y1;

S3. Preparation of reflective top coat: mixing and stirring the hydrophobically modified _TiO2 powder with the polymer solution to obtain a uniform suspension Y2;

S4. Preparation of the radiation bottom layer: after the diluted adhesive is evenly coated on the surface of the substrate, the suspension Y1 is evenly sprayed on the surface, and then dried to obtain the radiation bottom layer;

S5. Preparation of the reflective top layer: uniformly coat the suspension Y2 on the radiation bottom layer, dry to obtain the reflective top layer, and finally obtain a double-layer radiation cooling hydrophobic coating material.

Preferably, in step S1:

The concentration of the _TiO2 alcoholysis solution is 0.5-2g/100mL;

The concentration of the hydrophobic modifier alcoholysis solution is 0.1-20g/100mL;

The amount ratio of the _TiO2 alcoholysis solution to the hydrophobic modifier alcoholysis solution is 1.5-2.5:1;

The pH value is 7-11, preferably with ammonia water to adjust the pH value;

The temperature of the stirring reaction is 30-60°C, and the time is 0.5-2.5h;

The centrifugation is performed 2-5 times in total, each time for 10-30min, and the rotating speed is 8000-12000r/min;

The drying temperature is 40-120° C. and the drying time is 6-12 hours.

Preferably, the amount ratio of _SiO2 to polymer solution in the suspension Y1 in step S2 is 1-100g/100mL, and the stirring conditions are temperature 20-80°C, stirring speed 300-1000rpm, stirring time 15- 60min;

The dosage ratio of the hydrophobically modified _TiO2 powder and the polymer solution in the suspension Y2 in step S3 is 1-100g/100mL, and the stirring conditions are temperature 20-80°C, stirring speed 300-1000rpm, stirring time 15-60min.

Preferably, in step S4:

The coating method includes spraying, dripping, brushing or rolling;

The drying temperature of the radiation bottom layer is 40-80° C. and the drying time is 0.5-2 hours; the base material includes aluminum alloy, PVC board, wood board, polyester fabric and cotton fabric.

Preferably, the coating method in step S5 includes spray coating, drip coating, brush coating or rolling coating; the drying temperature of the reflective top layer is 40-80° C. and the drying time is 8-15 hours.

The double-layer radiative refrigeration hydrophobic coating material provided by the invention has good applications in the fields of textiles, building energy-saving materials, solar photovoltaic photothermal systems and the like.

Fig. 1 is a schematic diagram of the modification process of hydrophobically modified TiO ₂ in a preferred embodiment of the present invention. Fig. 2 is a schematic diagram of the structure of the double-layer radiative cooling hydrophobic coating material and the principle of radiative cooling in a preferred embodiment of the present invention. Mechanism of the present invention is:

Select one or more of CC, CO, CH and C-OH as the coating substrate, and add a polymer with high infrared emissivity and TiO ₂ and SiO ₂ with low solar absorption. The solar spectrum reflective layer on the top layer is composed of TiO ₂ , and the bottom "atmospheric window" band radiation layer is formed by SiO ₂ , the reflective layer can strongly scatter sunlight and has high reflectivity, while the radiant layer has high emissivity performance, This results in efficient cooling. At the same time, the hydrophobic modification of the coating can be realized after a large number of _TiO2 particles filled in the top layer are hydrophobically modified. A modifier with only CO and CH was selected, and the -OH on the surface of TiO ₂ reacted with the methoxy group (-OCH ₃ ) on the alkyltrimethoxysilane, and a large amount of -OH on the surface of TiO ₂ was grafted Numerous alkyltrimethoxysilane molecules, the hydrophobic group alkyl chains and _-OCH3 in the alkyltrimethoxysilane molecules are distributed on the surface of _TiO2 , which increases its radiative refrigeration performance while endowing it with hydrophobic properties. Therefore, a highly efficient radiative cooling hydrophobic coating material was finally obtained. At the same time, the adhesive is used to pre-spray on the bottom of the substrate, so that the radiant cooling coating can be applied to various substrate surfaces.

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

1. The radiation refrigeration particles (TiO ₂ and SiO ₂ ) used in the present invention are cheap, and the hydrophobic modification method is simple and easy to implement, and no additional high-cost equipment and complicated preparation conditions are required in the modification and coating preparation process, the method It is simple, can realize industrialized production, and solves the above-mentioned problems of large-scale production.

2. The present invention fully considers the influence of environmental humidity on the cooling effect of the coating, selects a suitable hydrophobic modifier, performs hydrophobic modification on the radiation cooling particles, and forms a synergistic cooling effect at the same time, further improves the cooling power, and realizes stability, high efficiency, Long-lasting cooling.

3. The present invention explores the radiation cooling effect of the coating on the surface of different materials, and finds that the prepared coating can be sprayed on the surface of many materials such as textiles, building materials, and photovoltaic materials to form an efficient and stable cooling coating. The resulting cooling coating It has a wide range of applications and strong universality, which expands the application potential of refrigeration coatings in different fields.

Description of drawings

Fig. 1 is the hydrophobically modified TiO that preferred embodiment of the present invention provides _The modified process schematic diagram;

Fig. 2 is a schematic diagram of the structure of the double-layer radiation cooling hydrophobic coating material and the principle of radiation cooling provided by the preferred embodiment of the present invention;

Fig. 3 is the apparent physical figure of the double-layer radiation cooling hydrophobic coating provided by the preferred embodiment of the present invention on the surface of different materials;

Fig. 4 is an infrared thermal image of the substrate and the double-layer radiative cooling hydrophobic coating material provided by the preferred embodiment of the present invention under sunlight;

Figure 5 shows the contact angle between the substrate and the double-layer radiative cooling hydrophobic coating provided by the preferred embodiment of the present invention. The contact angle has increased from 61° to 126°, which improves the hydrophobicity of the coating and improves the environmental stability.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. . Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The percentages involved in the preferred embodiments of the present invention are all mass percentages.

Example 1

Dissolve 1 g of TiO ₂ with a particle size of 0.5 μm, 0.8 μm, 1 μm, 3 μm, 5 μm, 8 μm, and 10 μm in 100 mL of absolute ethanol, stir magnetically for 30 minutes, and prepare a TiO ₂ alcoholysis solution for use; dissolve 1 g of MSDS In 50mL of absolute ethanol, stir magnetically for 30min to obtain the MSDS alcoholysis solution for later use; mix the prepared TiO ₂ with the MSDS alcoholysis solution, adjust the pH value to 9 with ammonia water, stir and react at 50°C for 2h, and the reaction ends Finally, the mixture was centrifuged at 10,000 rpm for 20 minutes at high speed, and the centrifugation was repeated 3 times; the TiO ₂ sample was dried at 60°C and constant temperature for 10 h to obtain dry hydrophobically modified TiO ₂ powder. Example 2

Dissolve 0.5g, 1.5g, and 2g of _TiO2 with a particle size of 5 μm in 100mL of absolute ethanol, stir magnetically for 30min, and prepare a _TiO2 alcoholysis solution for use; dissolve 1g of MSDS in 50mL of absolute ethanol, Stir magnetically for 30 minutes to obtain the MSDS alcoholysis solution for later use; mix the prepared TiO ₂ with the MSDS alcoholysis solution, adjust the pH value to 9 with ammonia water, stir and react at 50°C for 2 hours, and after the reaction is completed, mix the solution under the condition of 10000rpm Centrifuge at high speed for 20min, repeat centrifugation 3 times; dry the TiO ₂ sample at 60°C and constant temperature for 10h to obtain dry hydrophobically modified TiO ₂ powder.

Example 3

Dissolve 1g of _TiO2 with a particle size of 5μm in 100mL of absolute ethanol, stir magnetically for 30min, and prepare a _TiO2 alcoholysis solution for use; Dissolve in 50mL of absolute ethanol, stir magnetically for 30min, and obtain the HDTMS alcoholysis solution for later use; mix the prepared TiO ₂ with the HDTMS alcoholysis solution, adjust the pH value to 9 with ammonia water, stir and react at 50°C for 2h, and react After the end, the mixture was centrifuged at 10,000 rpm for 20 minutes at high speed, and the centrifugation was repeated 3 times; the TiO ₂ sample was dried at 60°C and constant temperature for 10 h to obtain dry hydrophobically modified TiO ₂ powder.

Example 4

Dissolve 1g of TiO ₂ with a particle size of 5 μm in 100mL of absolute ethanol, stir magnetically for 30min, and prepare a TiO ₂ alcoholysis solution for use; dissolve 0.2g, 0.5g, 1.5g, 2g, 5g, 10g of MSDS in In 50mL of absolute ethanol, stir magnetically for 30min to obtain the MSDS alcoholysis solution for later use; mix the prepared TiO ₂ with the MSDS alcoholysis solution, adjust the pH value to 9 with ammonia water, stir and react at 50°C for 2h, after the reaction is completed The mixture was centrifuged at 10,000 rpm for 20 minutes at high speed, and the centrifugation was repeated 3 times; the TiO ₂ sample was dried at 60°C and constant temperature for 10 h to obtain dry hydrophobically modified TiO ₂ powder.

Example 5

Dissolve 1g of _TiO2 with a particle size of 5μm in 100mL of absolute ethanol, stir magnetically for 30min, and prepare a _TiO2 alcoholysis solution for use; Dissolve in 50mL of absolute ethanol, stir magnetically for 30min to obtain MTMS alcoholysis solution for later use; mix the prepared TiO ₂ with MTMS alcoholysis solution, adjust the pH value to 9 with ammonia water, stir and react at 50°C for 2h, react After the end, the mixture was centrifuged at 10,000 rpm for 20 minutes at high speed, and the centrifugation was repeated 3 times; the TiO ₂ sample was dried at 60°C and constant temperature for 10 h to obtain dry hydrophobically modified TiO ₂ powder.

Example 6

Dissolve 1g of _TiO2 with a particle size of 5μm in 100mL of absolute ethanol and stir magnetically for 30min to prepare a _TiO2 alcoholysis solution for use; dissolve 1g of MSDS in 50mL of absolute ethanol and stir magnetically for 30min to obtain MSDS The alcoholysis solution is ready for use; mix the prepared TiO ₂ with the MSDS alcoholysis solution, adjust the pH value to 7, 8, 10, 11 with ammonia water, stir and react at 50°C for 2h, after the reaction is completed, mix the mixed solution at 10000rpm Centrifuge at high speed for 20min, repeat centrifugation 3 times; dry the TiO ₂ sample at 60°C and constant temperature for 10h to obtain dry hydrophobically modified TiO ₂ powder.

Example 7

Dissolve 1g of _TiO2 with a particle size of 5μm in 100mL of absolute ethanol and stir magnetically for 30min to prepare a _TiO2 alcoholysis solution for use; dissolve 1g of MSDS in 50mL of absolute ethanol and stir magnetically for 30min to obtain MSDS The alcoholysis solution is ready for use; mix the prepared TiO ₂ with the MSDS alcoholysis solution, adjust the pH value to 9 with ammonia water, stir and react at 30°C, 40°C, and 60°C for 2h, and after the reaction, mix the solution at 10000rpm Centrifuge at high speed for 20min, repeat centrifugation 3 times; dry the TiO ₂ sample at 60°C and constant temperature for 10h to obtain dry hydrophobically modified TiO ₂ powder.

Example 8

Dissolve 1g of _TiO2 with a particle size of 5μm in 100mL of absolute ethanol and stir magnetically for 30min to prepare a _TiO2 alcoholysis solution for use; dissolve 1g of MSDS in 50mL of absolute ethanol and stir magnetically for 30min to obtain MSDS The alcoholysis solution is ready for use; mix the prepared TiO ₂ with the MSDS alcoholysis solution, adjust the pH value to 9 with ammonia water, stir and react at 50°C for 0.5h, 1h, 1.5h, 2.5h, after the reaction is completed, mix the solution in Under the condition of 10000rpm, high-speed centrifugation for 20min, and repeated centrifugation for 3 times; the TiO ₂ sample was dried at 60°C and constant temperature for 10h to obtain dry hydrophobically modified TiO ₂ powder.

Example 9

Dissolve 1g of _TiO2 with a particle size of 5μm in 100mL of absolute ethanol and stir magnetically for 30min to prepare a _TiO2 alcoholysis solution for use; dissolve 1g of MSDS in 50mL of absolute ethanol and stir magnetically for 30min to obtain MSDS The alcoholysis solution is ready for use; mix the prepared TiO ₂ with the MSDS alcoholysis solution, adjust the pH value to 9 with ammonia water, stir and react at 50°C for 2 hours, and centrifuge the mixed solution at 10,000 rpm for 20 minutes at high speed after the reaction, repeat 3 times Secondary centrifugation; dry the TiO ₂ sample at 40°C, 80°C, 100°C, 120°C and constant temperature for 10h to obtain dry hydrophobically modified TiO ₂ powder.

Example 10

Dissolve 1g of _TiO2 with a particle size of 5μm in 100mL of absolute ethanol and stir magnetically for 30min to prepare a _TiO2 alcoholysis solution for use; dissolve 1g of MSDS in 50mL of absolute ethanol and stir magnetically for 30min to obtain MSDS The alcoholysis solution is ready for use; mix the prepared TiO ₂ with the MSDS alcoholysis solution, adjust the pH value to 9 with ammonia water, stir and react at 50°C for 2 hours, and centrifuge the mixed solution at 10,000 rpm for 20 minutes at high speed after the reaction, repeat 3 times Centrifuge once; dry the TiO ₂ sample at 60°C and constant temperature for 6h, 8h, 12h to obtain dry hydrophobically modified TiO ₂ powder.

In the following examples, the hydrophobically modified TiO ₂ powder is 1 g of TiO ₂ with a particle size of 5 μm and 1 g of HDTMS hydrophobically modified.

Example 11

Prepare 20%, 30%, 40%, 50% PVA solution, stir at 500rpm for 30min at 70°C, fully dissolve and set aside; mix 3g of 8μm SiO ₂ with 10mL PVA solution, then stir at 500rpm for 30min , to obtain a uniform suspension (Y1), set aside. Mix 1g of hydrophobically modified _TiO2 powder with 10mL of PVA solution, then stir at 500rpm for 30min to obtain a uniform suspension (Y2), which is ready for use. Use a spray gun to evenly spray the diluted adhesive on the surface of 10cm×10cm polyester fabric, spray the suspension (Y1) evenly on the surface, then dry the bottom layer at 60°C for 1 hour, and set aside; use a spray gun to evenly spray the suspension (Y2) sprayed on the bottom layer, and then dried at 60°C for 12 hours, and finally obtained a high-efficiency double-layer radiation cooling hydrophobic coating material.

Example 12

Prepare 20%, 30%, 40%, 50% cellulose solution, stir at 500rpm for 30min at 30°C, fully dissolve and set aside; mix 3g of 8μm SiO ₂ with 10mL cellulose solution, and then stir at 500rpm Stir for 30 minutes to obtain a uniform suspension (Y1), which is set aside. Mix 1g of hydrophobically modified _TiO2 powder with 10mL of cellulose solution, and then stir at 500rpm for 30min to obtain a uniform suspension (Y2), which is set aside. Use a spray gun to evenly spray the diluted adhesive on the surface of 10cm×10cm polyester fabric, spray the suspension (Y1) evenly on the surface, then dry the bottom layer at 60°C for 1 hour, and set aside; use a spray gun to evenly spray the suspension (Y2) sprayed on the bottom layer, and then dried at 60°C for 12 hours, and finally obtained a high-efficiency double-layer radiation cooling hydrophobic coating material.

Example 13

Prepare 20%, 30%, 40%, 50% acrylic acid solution, stir at 500rpm for 30min at 30°C, fully dissolve and set aside; mix 3g of 8μm _SiO2 with 10mL acrylic acid solution, then stir at 500rpm for 30min , to obtain a uniform suspension (Y1), set aside. Mix 1g of hydrophobically modified _TiO2 powder with 10mL of acrylic acid solution, and then stir at 500rpm for 30min to obtain a uniform suspension (Y2), which is set aside. Use a spray gun to evenly spray the diluted adhesive on the surface of 10cm×10cm polyester fabric, spray the suspension (Y1) evenly on the surface, then dry the bottom layer at 60°C for 1 hour, and set aside; use a spray gun to evenly spray the suspension (Y2) sprayed on the bottom layer, and then dried at 60°C for 12 hours, and finally obtained a high-efficiency double-layer radiation cooling hydrophobic coating material.

Example 14

Prepare 30% PVA solution, stir at 500rpm at 70°C for 30min, fully dissolve and set aside; mix 3g of 0.1μm, 0.5μm, 1μm, 3μm, 5μm, 10μm SiO ₂ with 10mL PVA solution, then at 500rpm Stir for 30 minutes to obtain a uniform suspension (Y1), which is set aside. Mix 1g of hydrophobically modified _TiO2 powder with 10mL of PVA solution, then stir at 500rpm for 30min to obtain a uniform suspension (Y2), which is ready for use. Use a spray gun to evenly spray the diluted adhesive on the surface of 10cm×10cm polyester fabric, spray the suspension (Y1) evenly on the surface, then dry the bottom layer at 60°C for 1 hour, and set aside; use a spray gun to evenly spray the suspension (Y2) sprayed on the bottom layer, and then dried at 60°C for 12 hours, and finally obtained a high-efficiency double-layer radiation cooling hydrophobic coating material.

Example 15

Prepare 30% PVA solution, stir at 500rpm at 70°C for 30min, fully dissolve and set aside; mix 0.1g, 0.5g, 1g, 5g, 10g of 8μm SiO ₂ with 10mL PVA solution, then stir at 500rpm After 30 minutes, a uniform suspension (Y1) was obtained and set aside. Mix 1g of hydrophobically modified _TiO2 powder with 10mL of PVA solution, then stir at 500rpm for 30min to obtain a uniform suspension (Y2), which is ready for use. Use a spray gun to evenly spray the diluted adhesive on the surface of 10cm×10cm polyester fabric, spray the suspension (Y1) evenly on the surface, then dry the bottom layer at 60°C for 1 hour, and set aside; use a spray gun to evenly spray the suspension (Y2) sprayed on the bottom layer, and then dried at 60°C for 12 hours, and finally obtained a high-efficiency double-layer radiation cooling hydrophobic coating material.

Example 16

Prepare 30% PVA solution, stir at 500rpm at 70°C for 30min, fully dissolve and set aside; mix 1g of 8μm SiO ₂ with 10mL PVA solution, then stir at 500rpm for 30min to obtain a uniform suspension (Y1) ,spare. Mix 1g of hydrophobically modified _TiO2 powder with 10mL of PVA solution, then stir at 500rpm for 30min to obtain a uniform suspension (Y2), which is ready for use. Use a spray gun to evenly spray the diluted adhesive on the surface of 10cm×10cm polyester fabric, then spray the suspension (Y1) evenly on the surface, then dry the bottom layer at 40°C and 80°C for 1 hour, and set aside; use a spray gun to spray the suspension (Y2) was uniformly sprayed on the bottom layer, and then dried at 60° C. for 12 hours to obtain a high-efficiency double-layer radiation refrigeration hydrophobic coating material.

Example 17

Prepare 30% PVA solution, stir at 500rpm at 70°C for 30min, fully dissolve and set aside; mix 1g of 8μm SiO ₂ with 10mL PVA solution, then stir at 500rpm for 30min to obtain a uniform suspension (Y1) ,spare. Mix 1g of hydrophobically modified _TiO2 powder with 10mL of PVA solution, then stir at 500rpm for 30min to obtain a uniform suspension (Y2), which is ready for use. Use a spray gun to evenly spray the diluted adhesive on the surface of 10cm×10cm aluminum alloy, PVC board, wood board, and cotton fabric, spray the suspension (Y1) evenly on the surface, then dry the bottom layer at 60°C for 1 hour, and set aside; use a spray gun The suspension (Y2) was uniformly sprayed on the bottom layer, and then dried at 60° C. for 12 hours to obtain a high-efficiency double-layer radiation cooling hydrophobic coating material.

Fig. 3 is the apparent physical figure of the double-layer radiation cooling hydrophobic coating obtained in this embodiment on the surface of polyester fabric, PVC and aluminum alloy materials. It can be seen that the surface of the sample is uniform and no bubbles are produced, which shows that the film-forming property is good and easy Processing can realize industrialized large-scale preparation. Figure 4 is an infrared thermal image of PVC and double-layer radiative cooling hydrophobic coating PVC material under sunlight. It can be seen from the figure that compared with PVC sheet, the presence of double-layer radiative cooling hydrophobic coating PVC material achieves a temperature of 4.7 °C. Cool down.

Example 18

Prepare 30% PVA solution, stir at 500rpm at 70°C for 30min, fully dissolve and set aside; mix 1g of 8μm SiO ₂ with 10mL PVA solution, then stir at 500rpm for 30min to obtain a uniform suspension (Y1) ,spare. Mix 0.1g, 0.5g, 3g, 5g, 10g of hydrophobically modified TiO ₂ powder with 10mL of PVA solution, and then stir at 500rpm for 30min to obtain a uniform suspension (Y2) for later use. Use a spray gun to evenly spray the diluted adhesive on the surface of 10cm×10cm polyester fabric, spray the suspension (Y1) evenly on the surface, then dry the bottom layer at 60°C for 1 hour, and set aside; use a spray gun to evenly spray the suspension (Y2) Spray on the bottom layer, and then dry at 60°C for 12 hours, and finally obtain a high-efficiency double-layer radiation cooling hydrophobic coating material.

Fig. 5 is the actual measurement diagram of the contact angle of the coating prepared by adding 5g of HDTMS hydrophobically modified _TiO2 powder and adding 5g of unmodified _TiO2 powder in the top coat. It can be seen from the figure that the coating prepared after adding 5g of unmodified TiO ₂ powder to the top coating shows obvious hydrophilicity, and the contact angle is only 61°, while the coating prepared by hydrophobically modified TiO ₂ powder The water contact angle on the coating has been significantly increased, and the contact angle can reach 126°. This is due to the substitution of long-chain alkyl groups for the hydroxyl groups on the surface of _TiO2 , and at the same time, due to the large amount of particles added in the coating, the hydrophobic performance of the coating is improved, thereby improving the environmental stability of the coating.

Example 19

Prepare 30% PVA solution, stir at 500rpm at 70°C for 30min, fully dissolve and set aside; mix 1g of 8μm SiO ₂ with 10mL PVA solution, then stir at 500rpm for 30min to obtain a uniform suspension (Y1) ,spare. Mix 1g of hydrophobically modified _TiO2 powder with 10mL of PVA solution, then stir at 500rpm for 30min to obtain a uniform suspension (Y2), which is ready for use. Use a spray gun to evenly spray the diluted adhesive on the surface of 10cm×10cm polyester fabric, spray the suspension (Y1) evenly on the surface, then dry the bottom layer at 60°C for 1 hour, and set aside; use a spray gun to evenly spray the suspension (Y2) sprayed on the bottom layer, and then dried at 40°C, 50°C, 70°C, and 80°C for 12 hours, and finally obtained a high-efficiency double-layer radiation refrigeration hydrophobic coating material.

Finally, it should be noted that: the above is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, it still The technical solutions recorded in the foregoing embodiments may be modified, or some of the technical features may be replaced equivalently, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the within the protection scope of the present invention.

Claims (10)

1. A double-layer radiation refrigeration hydrophobic coating material is characterized by comprising a radiation bottom coating and a reflection top coating, wherein:

the radiation primer comprises SiO ₂ And a polymer solution;

the reflective top coating comprises hydrophobically modified TiO ₂ Powder and polymer solution, the hydrophobically modified TiO ₂ Treating TiO powder with silane modifier ₂ Thus obtaining the compound.

2. The double-layer radiation-cooled hydrophobic coating material as claimed in claim 1, wherein the SiO is ₂ Has a particle diameter of 0.5 to 10 μm, and said TiO ₂ The particle diameter of (A) is 0.5-10 μm.

3. The double-layer radiation-refrigerating hydrophobic coating material as claimed in claim 1, wherein the polymer solution comprises polyethylene glycol solution, acrylic acid solution or cellulose solution; and/or

The silane modifier comprises hexadecyl trimethoxy silane HDTMS, octyl trimethoxy silane MSDS and methyl trimethoxy silane MTMS.

4. The double-layer radiation-cooled hydrophobic coating of claim 1Material, characterized in that the SiO ₂ And the amount of the polymer solution is 1 to 100g/100mL, and/or

The hydrophobically modified TiO ₂ The dosage ratio of the powder to the polymer solution is 1-100g/100mL, and/or

The mass concentration of the polymer solution is 20-50%, and/or

The silane modifier and TiO ₂ The mass and dosage ratio of (A) is 0.2-10:1.

5. a preparation method of a double-layer radiation refrigeration hydrophobic coating material is characterized by comprising the following steps:

s1, hydrophobic modified TiO ₂ Preparation of powder:

adding TiO into the mixture ₂ Dissolving in absolute ethyl alcohol to prepare TiO ₂ An alcoholysis solution; dissolving a silane modifier in absolute ethyl alcohol to obtain a hydrophobic modifier alcoholysis solution;

adding TiO into the mixture ₂ Mixing the alcoholysis solution and the alcoholysis solution of the hydrophobic modifier, adjusting the pH value to be neutral to alkalescence, and stirring for reaction at a certain temperature;

after the reaction is finished, centrifugally separating and drying the mixed solution to obtain the hydrophobic modified TiO ₂ Powder;

s2, preparing the radiation bottom coating: mixing SiO ₂ Mixing with the polymer solution, and stirring to obtain uniform suspension Y1;

s3, preparing a reflective top layer coating: modifying the hydrophobicity of TiO ₂ Mixing and stirring the powder and the polymer solution to obtain uniform suspension Y2;

s4, preparing a radiation bottom layer: uniformly coating the diluted adhesive on the surface of a base material, uniformly spraying the suspension Y1 on the surface, and drying to obtain a radiation bottom layer;

s5, preparing a reflecting top layer: and uniformly coating the suspension Y2 on the radiation bottom layer, drying to obtain a reflection top layer, and finally obtaining the double-layer radiation refrigeration hydrophobic coating material.

6. The preparation method of the double-layer radiation refrigeration hydrophobic coating material according to claim 5, wherein in the step S1:

the TiO is ₂ The concentration of the alcoholysis solution is 0.5-2g/100mL;

the concentration of the hydrophobic modifier alcoholysis solution is 0.1-20g/100mL;

the TiO is ₂ The dosage ratio of the alcoholysis solution to the hydrophobic modifier alcoholysis solution is 1.5-2.5:1;

the pH value is 7-11, and is preferably adjusted by ammonia water;

the temperature of the stirring reaction is 30-60 ℃, and the time is 0.5-2.5h;

the centrifugal separation is carried out for 2-5 times, each time is 10-30min, and the rotating speed is 8000-12000r/min;

the drying temperature is 40-120 ℃, and the drying time is 6-12h.

7. The method for preparing the hydrophobic coating material for double-layer radiation refrigeration according to claim 5, wherein SiO in the suspension Y1 in the step S2 is SiO ₂ The dosage ratio of the polymer solution and the polymer solution is 1-100g/100mL, and the stirring conditions are that the temperature is 20-80 ℃, the stirring speed is 300-1000rpm, and the stirring time is 15-60min;

in step S3, the hydrophobic modified TiO in the suspension Y2 ₂ The dosage ratio of the powder to the polymer solution is 1-100g/100mL, and the stirring conditions are that the temperature is 20-80 ℃, the stirring speed is 300-1000rpm, and the stirring time is 15-60min.

8. The method for preparing the double-layer radiation refrigeration hydrophobic coating material according to claim 5, wherein in the step S4:

the coating mode comprises spraying, dripping, brushing or rolling;

the drying temperature of the radiation bottom layer is 40-80 ℃, and the drying time is 0.5-2h; the base material comprises aluminum alloy, a PVC plate, a wood plate, polyester fabric and cotton fabric.

9. The method for preparing the double-layer radiation refrigeration hydrophobic coating material according to the claim 5, wherein the coating manner in the step S5 comprises spraying, dripping, brushing or rolling; the drying temperature of the reflecting top layer is 40-80 ℃, and the drying time is 8-15h.

10. Use of the double-layer radiation-cooling hydrophobic coating material according to any one of claims 1 to 9 in textiles, building energy saving materials, solar photovoltaic-optical thermal systems.

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