CN108483934A - A kind of tungsten bronze/silica dioxide gel heat-insulation functional material and preparation method thereof - Google Patents

Abstract

The invention discloses a kind of tungsten bronze/silica dioxide gel heat-insulation functional materials and preparation method thereof, and the functional material is using silica and tungsten bronze as primary raw material, and by 100% silica of mass fraction, 10 15% tungsten bronzes are combined；Preparation method is：Transparent silica dioxide gel is first prepared under the catalysis of catalyst with sol-gal process, it is spare after aged, dilution, filtering；Function tungsten bronze nano-particle is scattered in liquid alcohol, through grinding for several times, ultrasound, then with silica dioxide gel be mixed；On the glass sheet with coating by gained functional paint, dry, sintering, then repeatedly spin coating, until film thickness reaches required thickness.Function film made from this method maintains good near-infrared shielding properties compared with common organic film, and thermal stability is remarkably improved.

Description

A kind of tungsten bronze/silica gel thermal insulation functional material and its preparation method

technical field

The invention belongs to the technical field of transparent layers, and in particular relates to a tungsten bronze/silicon dioxide gel thermal insulation functional material and a preparation method thereof.

Background technique

With the substantial growth of our country's building area, the problem of building energy consumption has become more and more serious, which has caused great pressure on energy supply and ecological environment. At present, my country's building energy consumption accounts for about 30% of the total energy consumption of the society. Among these energy consumption, heating energy consumption in winter in the north and air conditioning energy consumption in summer in the south account for the main part. The area of door and window glass accounts for about 30% of the outer structure of the building. It is the main channel for energy exchange between the building and the environment, and it is the main part that causes building energy consumption. Its energy dissipation accounts for about 2/3 of the total building energy consumption. Transparent heat insulation materials can shield the radiation of near-infrared light (wavelength range 1000-2500nm) on the premise of maintaining visible light and visual transparency, thereby reducing solar energy intake, which can effectively reduce air-conditioning energy consumption in summer and reduce energy consumption in winter. The indoor heat is diffused outwards to realize the purpose of building energy saving.

In recent years, great progress has been made in the use of nanoparticles dispersed in transparent coatings to block near-infrared light. Applying them to the glass of buildings or cars can reduce the energy consumption of air conditioners, thereby reducing the emission of greenhouse gases. emission. Traditional energy-saving windows (electrochromic glass, aerochromic glass, etc.) have complex structures and sometimes require energy input, while transparent coatings dispersed with near-infrared blocking nanoparticles are relatively simple and more efficient in terms of energy saving.

Near-infrared shielding materials generally refer to a class of functional thin film materials that have strong absorption or reflection of near-infrared light without affecting the transmission of visible light. The more well-known near-infrared shielding nanomaterials include the following categories: noble metals (Ag, Au, etc.), semiconductor oxides (ATO, ITO, etc.), rare earth hexaborides (LaB6, PrB6, NdB6). Surface plasmon resonance makes these nanomaterials have the property of shielding near-infrared, but they have their own advantages and disadvantages: films containing noble metal particles have low transmittance in the visible region; ATO and ITO are relatively stable and have high transmittance in the visible region. transmittance, but they can only effectively shield near-infrared light with a wavelength greater than 1500nm; hexaboride insulation materials can only shield near-infrared light with a certain wavelength, and due to the high hardness of rare earth hexaboride, it must be grind.

Tungsten bronze (M _x WO ₃ , M is Na+, K ⁺ , Rb ⁺ , Cs ⁺ and NH ₄ ⁺ ) has been reported as the most promising heat shielding material in recent years. It has high visible light transmittance and can shield wavelength Near-infrared light greater than 1000nm, so it has more excellent near-infrared shielding performance. In the prior art, Chinese patent CN104528829A discloses a preparation method of cesium tungsten bronze powder; and Chinese patent CN104726040A discloses a preparation method of PVB slurry containing tungsten bronze; Xiaoyong Wu et al. (Nanoscale.2015.7 (40) : 17048-17054.) prepared a novel Cs _x WO ₃ /ZnO smart window coating material, which not only has excellent thermal insulation performance, but also can catalyze and decompose harmful NO gas in the air under the action of light, but the process is relatively Complicated; In addition, Jingxiao Liu et al. (Applied Surface Science.2014.309:175-180.) stated that the choice of dispersant has a non-negligible impact on the near-infrared shielding performance of tungsten bronze nanoparticles.

Contents of the invention

Aiming at the deficiencies of the existing problems, the purpose of the present invention is to provide a tungsten bronze/silica gel thermal insulation functional material and its preparation method; the present invention aims to prepare a transparent thermal insulation coating with excellent performance, and optimize the production process, improve the thermal stability of the clear coat, and reduce the application cost.

The technical scheme that the present invention solves its technical problem adopts is:

A tungsten bronze/silicon dioxide gel thermal insulation functional material is composed of silicon dioxide and tungsten bronze as main raw materials, 100% silicon dioxide and 10-15% tungsten bronze by mass fraction.

As a preferred technical solution of the present application, the silicon dioxide is catalyzed by a catalyst and prepared by a sol-gel method, and the catalyst is selected from any one of hydrochloric acid, sulfuric acid or ammonia water.

The preparation method of the above-mentioned tungsten bronze/silica gel thermal insulation functional material comprises the following steps:

(1) Mix and stir ethyl orthosilicate and absolute ethanol according to a volume ratio of 1:1, heat to reflux, add a catalyst, and continue to reflux at 70-80°C for 2 hours, and after the reaction is completed, seal and age at room temperature for more than 24 hours. Dilute with liquid alcohol, stir, and filter with a microporous membrane to obtain silica gel;

(2) Weigh tungsten bronze nanoparticles and disperse them in ethanol, grind them separately, ultrasonicate them, and then stir and mix them with silica gel to obtain functional coatings;

(3) Take a clean glass substrate, apply the functional coating obtained in step (2) on the glass substrate, dry naturally at room temperature, and then heat up to 200°C at a heating rate of 1°C/min for sintering;

(4) Step (3) is repeated until the obtained film on the glass substrate reaches the required thickness.

As the preferred technical solution of the present application, the tungsten bronze nanoparticles in the step (2) are CsxWO3, and the specific preparation method is as follows:

(1) Dissolve tungsten chloride in absolute ethanol, stir vigorously to obtain a light yellow solution, then add cesium hydroxide monohydrate, and after the solution is uniformly mixed, add acetic acid;

(2) Transfer the obtained precursor solution to a high-pressure reactor and react at 160-240° C.; the obtained dark blue product is centrifuged, washed with water and ethanol respectively, and finally vacuum-dried to obtain the product.

As a preferred technical solution of the present application, the glass substrate in the step (3) is first ultrasonically cleaned with absolute ethanol, then cleaned with sulfuric acid, surface hydroxylated, and finally deionized water ultrasonically cleaned.

As a preferred technical solution of the present application, the catalyst in the step (1) is hydrochloric acid with a concentration of 0.01mol/L.

As a preferred technical solution of the present application, the alcohol selected in the step (1) is ethanol or ethylene glycol.

As a preferred technical solution of the present application, the coating method in the step (3) is a spin coating method or an extraction method.

Preferably, when using the spin coating method, the rotation speed is 3000r/min, and the time is 20s.

Compared with the prior art, the tungsten bronze/silica gel thermal insulation functional material and its preparation method provided by the present invention have the following beneficial effects:

(1) The present invention prepares functional films on glass substrates by compounding silica gel and tungsten bronze. Due to the characteristics of SiO ₂ gel films that are smooth, compact and have few defects, compared with ordinary organic films, the sintered two Silicon oxide film has good thermal stability;

( ₂ ) The present invention explores and prepares SiO through experiment The optimum technique of gel film, on this basis, changes the proportioning ratio of silicon dioxide and tungsten bronze nanoparticle, finally finds that 1200nm wavelength near-infrared light can be absorbed by tungsten bronze The transmittance is reduced from 90% to 10%.

Description of drawings

Figure 1 is the UV-Vis-NIR spectrum of glass coated with tungsten bronze/silica gel functional film. Wherein what curve a represented was the near-infrared shielding performance figure of embodiment 1; What curve b represented was the near-infrared shielding performance figure of embodiment 2; What curve c represented was the near-infrared shielding performance figure of embodiment 3; Curve d was blank The transmittance curve of the silica gel coating;

Fig. 2 is the SEM image of the tungsten bronze/silica gel functional thin film of Example 2 (1200X, 100000X from left to right).

Detailed ways

The present invention is described in further detail below in conjunction with embodiment. The reagents or instruments used are not indicated by the manufacturer, and they are all regarded as conventional products that can be purchased through the market.

Example 1:

(1) Mix and stir 5ml tetraethyl orthosilicate and 5ml absolute ethanol, add 1.61ml of 0.1mol/L dilute hydrochloric acid dropwise after heating to reflux, and continue the reflux reaction at 70°C for 2h; after the reaction, airtight aging at room temperature 24h, dilute with ethanol with a volume ratio of 1:3, stir for 10min, and filter with a 0.2um microporous membrane to obtain _SiO2Gel ;

(2) Weigh 0.05g of Cs _x WO ₃ nanoparticles and disperse them in ethanol, grind them separately, ultrasonicate 3 times, then stir and mix them with SiO ₂ gel, the mass fraction of Cs _x WO ₃ is 10%, to obtain a functional coating;

(3) Take a clean glass substrate, and spin-coat the functional coating on the glass substrate; the spin-coating speed is 3000r/min, and the time is 20s; the glass plate coated with the functional film is naturally dried at room temperature, and then heated at a rate of 1°C/min Heat up to 200°C for sintering;

(4) Repeat step 3 until the film obtained on the glass plate reaches the required thickness; finally test the near-infrared shielding performance of the glass.

The transmittance curve of the glass coating prepared by this method is shown in curve a in FIG. 1 , the transmittance of visible light is 52%, and the transmittance of near-infrared light is about 17%.

Example 2:

(1) Mix and stir 5ml tetraethyl orthosilicate and 5ml absolute ethanol, add 1.61ml of 0.1mol/L dilute hydrochloric acid dropwise after heating to reflux, and continue the reflux reaction at 80°C for 2h; after the reaction, airtight aging at room temperature 24h, dilute with ethanol with a volume ratio of 1:2, stir for 10min, and filter with a 0.2um microporous membrane to obtain _SiO2Gel ;

(2) Weigh 0.05g of tungsten bronze nanoparticles and disperse them in ethanol, grind them respectively, and ultrasonicate them three times, then stir and mix them with SiO ₂ gel, the mass fraction of Cs _x WO ₃ is 15%, to obtain a functional coating;

(3) Take a clean glass substrate, and spin-coat the functional coating on the glass substrate; the spin-coating speed is 2000r/min, and the time is 20s; the glass plate coated with the functional film is naturally dried at room temperature, and then heated at a rate of 1°C/min Heat up to 200°C for sintering;

(4) Repeat step 3 until the film obtained on the glass plate reaches the required thickness; finally test the near-infrared shielding performance of the glass.

The transmittance curve of the glass coating prepared by this method is shown in curve b in FIG. 1 , the transmittance of visible light is 63%, and the transmittance of near-infrared light is about 7%.

Example 3:

(1) Mix and stir 5ml tetraethyl orthosilicate and 5ml absolute ethanol, add 1.61ml of 0.1mol/L dilute hydrochloric acid dropwise after heating to reflux, and continue the reflux reaction at 70°C for 2h; after the reaction, airtight aging at room temperature 24h, dilute with ethanol with a volume ratio of 1:3, stir for 10min, and filter with a 0.2um microporous membrane to obtain _SiO2Gel ;

(2) Weigh 0.05g of tungsten bronze nanoparticles and disperse them in ethanol, grind them respectively, and ultrasonicate them three times, then stir and mix them with SiO ₂ gel, the mass fraction of Cs _x WO ₃ is 15%, to obtain a functional coating;

(3) Take a clean glass substrate, and spin-coat the functional coating on the glass substrate; the spin-coating speed is 3000r/min, and the time is 20s; the glass plate coated with the functional film is naturally dried at room temperature, and then heated at a rate of 1°C/min Heat up to 200°C for sintering;

(4) Repeat step 3 until the film obtained on the glass plate reaches the required thickness; finally test the near-infrared shielding performance of the glass.

The transmittance curve of the glass coating that this method makes is shown in curve c in Fig. 1, and visible light transmittance is 71%, and near-infrared light transmittance is about 6%; As shown in Figure 2, it can be seen that the coating is smooth, dense and has few defects.

Example 4:

(1) Mix and stir 5ml tetraethyl orthosilicate and 5ml absolute ethanol, add 1.61ml of 0.1mol/L dilute hydrochloric acid dropwise after heating to reflux, and continue the reflux reaction at 70°C for 2h; after the reaction is completed, airtight aging at room temperature For 24 hours, dilute with ethanol with a volume ratio of 1:3, stir for 10 minutes, and filter with a 0.2um microporous membrane to obtain a silica gel;

(2) Take a clean glass substrate, and spin-coat silica gel on the glass substrate; the spin-coating speed is 3000r/min, and the time is 20s; The heating rate is raised to 200°C for sintering;

(4) Repeat step 3 until the film obtained on the glass plate reaches the required thickness; finally test the near-infrared shielding performance of the glass.

The transmittance curve of the glass coating only coated with silica gel obtained by this method is shown in curve d in Figure 1, the visible light transmittance is close to 90%, and the near-infrared light transmittance is higher than 90%. The peaks between 800-900nm are produced by the instrument automatically switching the light source during the measurement.

The protection content of the present invention is not limited to the above embodiments. Without departing from the spirit and scope of the inventive concept, changes and advantages that can be conceived by those skilled in the art are all included in the present invention, and the appended claims are the protection scope.

Claims (9)

1. A tungsten bronze/silica gel thermal insulation functional material, characterized in that, silicon dioxide and tungsten bronze are used as the main raw materials, and the mass fraction is 100% silicon dioxide and 10-15% tungsten bronze. . 2. The tungsten bronze/silica gel thermal insulation functional material according to claim 1, characterized in that the silica is catalyzed by a catalyst and prepared by a sol-gel method, and the catalyst is selected from hydrochloric acid, sulfuric acid or any one in ammonia water. 3. The preparation method of tungsten bronze/silica gel thermal insulation functional material according to claim 1, characterized in that, comprising the steps of: (1) Mix and stir ethyl orthosilicate and absolute ethanol according to a volume ratio of 1:1, heat to reflux, add a catalyst, and continue to reflux at 70-80°C for 2 hours, and after the reaction is completed, seal and age at room temperature for more than 24 hours. Dilute with liquid alcohol, stir, and filter with a microporous membrane to obtain silica gel; (2) Weigh tungsten bronze nanoparticles and disperse them in ethanol, grind them separately, ultrasonicate them, and then stir and mix them with silica gel to obtain functional coatings; (3) Take a clean glass substrate, coat the functional coating obtained in step (2) on the glass substrate, dry naturally at room temperature, and then heat up and sinter; (4) Step (3) is repeated until the obtained film on the glass substrate reaches the required thickness. 4. the preparation method of tungsten bronze/silicon dioxide thermal insulation functional material according to claim 3, is characterized in that, in described step (2), tungsten bronze nano-particle is CsxWO3, and concrete preparation method is as follows: (1) Dissolve tungsten chloride in absolute ethanol, stir vigorously to obtain a light yellow solution, then add cesium hydroxide monohydrate, and after the solution is uniformly mixed, add acetic acid; (2) Transfer the obtained precursor solution to a high-pressure reactor and react at 160-240° C.; the obtained dark blue product is centrifuged, washed with water and ethanol respectively, and finally vacuum-dried to obtain the product. 5. the preparation method of tungsten bronze/silicon dioxide thermal insulation functional material according to claim 3 is characterized in that, the glass substrate in the described step (3) is first ultrasonically cleaned with dehydrated alcohol, then cleaned with sulfuric acid, Hydroxylation of the surface, and finally ultrasonic cleaning with deionized water. 6. The preparation method of tungsten bronze/silicon dioxide thermal insulation functional material according to claim 3, characterized in that the catalyst in the step (1) is hydrochloric acid with a concentration of 0.01mol/L. 7. The preparation method of tungsten bronze/silicon dioxide thermal insulation functional material according to claim 3, characterized in that the alcohol selected in the step (1) is ethanol or ethylene glycol. 8. The preparation method of tungsten bronze/silicon dioxide thermal insulation functional material according to claim 3, characterized in that, the coating method in the step (3) is a spin coating method or an extraction method. 9. The preparation method of tungsten bronze/silicon dioxide thermal insulation functional material according to claim 8, characterized in that, when using the spin coating method, the rotation speed is 3000r/min, and the time is 20s.