CN102408806B - Transparent thermal insulation coating with high emission in atmospheric window area and preparation method thereof - Google Patents

Abstract

The invention discloses a high-emission transparent heat-insulating paint in atmospheric window regions. The main material of the transparent heat-insulating paint is prepared from the following components in parts by weight: 30-70 parts of polymer emulsion, 10-30 parts of nano doped oxide powder, 2-30 parts of high-emission nano powder in atmospheric window regions, 1-10 parts of anionic dispersant, 2-20 parts of nonionic dispersant, 0.5-2 parts of defoaming agent, 0-5 parts of thickening agent, 1-2 parts of film forming assistant, 1-2 parts of antifreezing agent, 1-2 parts of leveling agentand 5-20 parts of distilled water. The invention also discloses a preparation method of the transparent heat-insulating paint, which comprises the following steps: after evenly mixing the components,regulating the pH value to 8.5-9.5 with a multifunctional assistant AMP-95 to obtain the high-emission-rate transparent heat-insulating paint in atmospheric window regions. The paint has high emission rate in atmospheric window regions, and can implement effective heat dissipation.

Description

Transparent thermal insulation coating with high emission in atmospheric window area and preparation method thereof

technical field

The invention relates to a coating, in particular to a high-emission transparent heat-insulating coating which can be coated on the atmospheric window area of the outer surface of building or vehicle window glass and a preparation method thereof.

Background technique

From the point of view of thermal radiation, outer space can be approximated as a black body with an absolute temperature of zero. If a black body with a temperature of T=300K is set outside the atmosphere (blocking the direct sunlight); then it will be gradually cooled down. According to the Stephen-Boltzmann law, the energy W per unit area radiated into outer space can be calculated:

W＝αT ⁴ ＝5.7×10 ^-8 ×300 ⁴ ≈450W/m ²

This value is a very high cooling capacity. In outer space, good thermal insulation can be obtained by using radiant coatings. The National Aeronautics and Space Administration (NASA) developed a new type of high-radiation coating (Emisshield) technology in 1994 and used it for the X-33 and X-34 orbiters. The product has an emissivity as high as 0.8-0.9 at room temperature, and its service temperature can reach 3000F or even higher.

But within the atmosphere, because the atmosphere blocks part of the infrared radiation from reaching outer space, its cooling effect will be greatly reduced. Because within the atmosphere, not all radiation emitted by the Earth passes through space. A considerable portion of the radiation is absorbed by the Earth's atmosphere and re-emitted to the Earth's surface.

The infrared radiation of the atmosphere mainly comes from water vapor, carbon dioxide, ozone and suspended particles in the atmosphere, among which water vapor and carbon dioxide play a major role. In the wavelength range of 8-13.5 μm, the infrared absorption ability of water vapor and carbon dioxide is weak, so the infrared radiation ability in this wave band is also weak, which makes the atmosphere have a strong effect on the infrared radiation of 8-13.5 μm. For high transparency, we call the wavelength range of 8-13.5μm the "atmospheric window". In practical applications, such an infrared window can be used to achieve the purpose of radiation cooling.

Figure 1 shows the relationship between the radiation power of the radiator in the atmosphere and the radiation power projected on the radiator by the sky and the wavelength. It can be seen that when the radiation heat loss is consistent with the heat gain, the temperature of the radiator can reach the lowest value. On a clear, cloudless night, a blackbody can cool down to 10-20°C below the ambient air temperature. Figure 2 shows the case where the radiator is an ideal black body in the range of 8-13.5 μm, and the ideal reflector in other ranges. It can be seen that such a radiator can be lowered to a lower temperature than a black body.

Transparent thermal insulation paint is a paint that can form a transparent coating after application, and the coating has strong blocking properties against sunlight in the near-infrared region. US patent US5518810 Infrared ray cutoff material and infrared cutoff powder use for same describes a coating formed by dispersing tin-doped indium oxide powder in inorganic or organic polymers, which is transparent in the visible light region and can block wavelengths above 1000nm Near-infrared light, so as to achieve the purpose of heat insulation.

Among the patents related to transparent heat-insulating coatings—such as the Chinese patent "Nano-transparent heat-insulating composite coating and its thermal insulation effect test device" with the application number 200410014672.4, and the Chinese patent "An infrared shielding device" with the application number 201010199580.3 type glass thermal insulation coating and its preparation method”—both use nano-doped oxides as functional fillers. However, due to the strong absorption of nano-doped oxides on infrared rays and their low infrared emissivity, the coating continuously absorbs solar infrared radiation, but cannot be effectively cooled by thermal radiation. Therefore, the surface coated with the coating will rise to a very high temperature under the sunlight-especially the midday sun in summer-and after the direct sunlight is over, because the coating is in the infrared region-especially With low emissivity in the atmospheric window region, the cooling process of the surface to which the coating is applied also proceeds very slowly. If the coating is in a high temperature state for a long time, it will increase the cooling load inside the building or vehicle, and affect the service life of the coating.

And if the coating has high emission performance in the atmospheric window area, it can be cooled quickly after direct sunlight, effectively reducing the time the coating surface stays at a higher temperature, reducing the cooling load inside buildings or vehicles, and prolonging the life of the coating. Coating service life.

The high emissivity of the coating is widely used in opaque solar heat reflective coatings to avoid excessive heat accumulation on the surface of the coating. According to the Chinese patent "solar heat radiation reflective coating" with the publication number CN 101812269 A, Include 20-70% film-forming substance, 20-60% solvent, 2-10% hollow particle, 2-10% infrared powder, 0.1-1% nano-titanium dioxide, 4-20% additive to obtain the coating by weight percentage, after After coating and forming a film, at least achieve a full-spectrum solar heat reflectance greater than or equal to 85%, and a hemispherical emissivity greater than or equal to 85%. Publication number is CN 101565581A Chinese patent "reflective thermal insulation coating and its preparation method" described in the reflective thermal insulation coating, its full-spectrum solar reflectance is 0.87, and its hemispherical emissivity is 0.87. However, these coatings are not transparent and cannot meet the requirements of transparent coatings.

Contents of the invention

The technical problem to be solved by the present invention is to provide a transparent heat-insulating coating with high emission in the atmospheric window, which can overcome the problem that the transparent heat-insulating coating disclosed in the prior art has a low emissivity in the atmospheric window area and cannot effectively dissipate heat insufficient.

In order to solve the above technical problems, the present invention provides a transparent heat-insulating coating with high emission in the atmospheric window area. The main material of the transparent heat-insulating coating is composed of the following components by weight: 30-70 parts of polymer emulsion, 10-30 parts of powder, 2-30 parts of nano powder with high emission in the atmospheric window area, 1-10 parts of anionic dispersant, 2-20 parts of non-ionic dispersant, 0.5-2 parts of defoamer, thickener 0-5 parts, 1-2 parts of film-forming aid, 1-2 parts of antifreeze, 1-2 parts of leveling agent and 5-20 parts of distilled water.

As the improvement of the highly emissive transparent heat-insulating coating in the atmospheric window area of the present invention:

The polymer emulsion is polyacrylate emulsion, styrene-acrylic emulsion or silicone-acrylic emulsion;

The nano-doped oxide powder is at least one of antimony-doped tin dioxide, fluorine-doped tin dioxide, gallium-doped zinc oxide, aluminum-doped zinc oxide and indium tin oxide with a particle size range of 5 to 60 nm;

The nano-powders with high emission in the atmospheric window area are silica, mullite powder, silicon carbide, alumina and aluminosilicate (xAl ₂ O ₃ ·ySiO ₂ ) with a particle size ranging from 5 to 60 nm. at least one;

Anionic dispersant is sodium hexametaphosphate, sodium tripolyphosphate or polymer anionic dispersant;

The non-ionic dispersant is dispersant DP270 (that is, polyacrylate dispersant DP270);

The defoamer is 090 defoamer, SPA-202 defoamer, Dapro DF 7010 defoamer or tributyl phosphate;

The thickener is hydroxyethyl cellulose ether;

The film-forming aid is alcohol ester-12;

Antifreeze is propylene glycol;

The leveling agent is polypropylene oxide.

The present invention also simultaneously provides a method for preparing the above-mentioned high-emission transparent heat-insulating coating in the atmospheric window region, which includes the following steps in sequence:

1) Add distilled water, anionic dispersant, nonionic dispersant, and 25-35% (by weight) defoamer in sequence under low-speed stirring, and stir well;

2) In the mixture obtained in step 1), add nano-doped oxide powder and high-emission nano-powder in the atmospheric window area in sequence, and after stirring evenly, add 1/2 to 1/4 (weight ratio) of thickening The antifoaming agent and 35～45% (weight ratio) are stirred evenly to obtain the color paste; the color paste is placed in a high-speed disperser and dispersed for 30 minutes;

3) Add coalescent, antifreeze and leveling agent to the polymer emulsion under low-speed stirring;

4), add the color paste obtained in step 2) to the result of step 3), and then stir at a low speed. During the stirring process, add the remaining defoamer and the remaining thickener dropwise, and use the multifunctional additive AMP-95 to adjust the pH to 8.5～9.5, transparent thermal insulation coating with high emission in the atmospheric window area.

In the present invention, low-speed stirring refers to 300-400r/min; in step 2), nano-doped oxide powder and high-emission nano-powder in the atmospheric window area are sequentially added, and the rotating speed of the high-speed disperser is 3000-4000r/min .

The beneficial effect of the present invention is that: the present invention has the following performances by adding nano particles with a reasonable ratio of high emission in the atmospheric window area: the emission rate in the atmospheric window area is high, and effective heat dissipation can be realized.

Description of drawings

The specific implementation manners of the present invention will be described in further detail below in conjunction with the accompanying drawings.

Fig. 1 is the radiant power representing the radiation body in the atmosphere and the relationship diagram between the radiation power and the wavelength projected on the radiation body by the sky;

Figure 2 shows that when the radiator is an ideal black body in the range of 8-13.5 μm, and the ideal reflector is surrounded in other ranges, the relationship between the radiation power of the radiator and the radiation power projected on the radiator by the sky and the wavelength picture.

Detailed ways

The parts in the following examples are all parts by weight.

Embodiment 1, a transparent heat-insulating coating with high emission in the atmospheric window area, by weight, the main material of the transparent heat-insulating coating is composed of the following components: 50 parts of polyacrylate emulsion, nanometer antimony-doped tin dioxide (particle diameter 5-60nm) 15 parts, nano-mullite powder (particle size 5-60nm) 15 parts, 2 parts of sodium hexametaphosphate as an anionic dispersant, 4 parts of DP270 dispersant as a non-ionic dispersant , 1 part of 090 defoamer, 3 parts of hydroxyethyl cellulose ether as a thickener, 1 part of polypropylene oxide as a leveling agent, 1 part of alcohol ester-12 as a film-forming aid, as an antifreeze 1 part of propylene glycol, 7 parts of distilled water.

Its preparation method is to carry out following steps successively:

1), Premix:

Add 7 parts of distilled water, 2 parts of sodium hexametaphosphate, 4 parts of DP270 dispersant and 0.3 part of 090 defoamer in sequence under low-speed stirring (300-400r/min), and stir well (stir for 30 minutes);

2), high-speed dispersion:

Add 15 parts of nano-antimony-doped tin dioxide and 15 parts of nano-mullite powder to the mixture obtained in step 1), and stir evenly (stirring for 30 minutes), then add 1 part of hydroxyethyl cellulose ether and 090 disinfectant Stir 0.4 parts of the foaming agent evenly (stir for 30 minutes) to obtain the color paste; place the color paste in a high-speed disperser (3000-4000r/min) for 30 minutes to disperse.

3) Under low-speed stirring (300-400r/min), add 1 part of alcohol ester-12, 1 part of propylene glycol and 1 part of polypropylene oxide to 50 parts of polyacrylate emulsion;

4) Add the dispersed color paste obtained in step 2) to the obtained product in step 3), then stir at a low speed (300-400r/min) for 30 minutes, add the remaining 0.3 parts of 090 defoamer and the remaining Thickener (hydroxyethyl cellulose ether) 2 parts, and adjust PH to 9 by AMP-95, filter (through 400 mesh screen, the purpose is to remove the impurity that may exist), obtain the transparent Insulation paint.

Embodiment 2, a transparent heat-insulating coating with high emission in the atmospheric window, by weight, the main material of the transparent heat-insulating coating is made up of the following components: 50 parts of styrene-acrylic emulsion, fluorine-doped tin dioxide (particle diameter is 5～ 60nm) 15 parts, nano mullite powder (particle size 5 ~ 60nm) 15 parts, sodium hexametaphosphate as an anionic dispersant 2.5 parts, DP270 dispersant as a nonionic dispersant 5 parts, 090 1 part of foaming agent, 3 parts of hydroxyethyl cellulose ether as a thickener, 1 part of polypropylene oxide as a leveling agent, 1 part of alcohol ester-12 as a coalescent, 1 part of propylene glycol as an antifreeze parts, 6 parts of distilled water.

Its preparation method is to carry out following steps successively:

1), Premix:

Add 6 parts of distilled water, 2.5 parts of sodium hexametaphosphate, 5 parts of DP270 dispersant and 0.3 part of 090 defoamer in sequence under low-speed stirring (300-400r/min), and stir well (stir for 30 minutes);

2), high-speed dispersion:

Add 15 parts of fluorine-doped tin dioxide and 15 parts of nano-mullite powder to the mixture obtained in step 1), and stir evenly (stirring for 30 minutes), then add 1 part of hydroxyethyl cellulose ether and 090 defoaming Mix 0.4 parts of the agent evenly (stir for 30 minutes) to obtain the color paste; place the color paste in a high-speed disperser for 30 minutes (3000-4000r/min).

3) Under low-speed stirring (300-400r/min), add 1 part of alcohol ester-12, 1 part of propylene glycol and 1 part of polypropylene oxide to 50 parts of styrene-acrylic emulsion;

4) Add the dispersed color paste obtained in step 2) to the obtained product in step 3), then stir at a low speed (300-400r/min) for 30 minutes, add the remaining 0.3 parts of 090 defoamer and the remaining Thickener (hydroxyethyl cellulose ether) 2 parts, and through AMP-95 to adjust the pH to 9, filtered to obtain a transparent heat-insulating coating with high emission in the atmospheric window area.

Embodiment 3, a transparent heat-insulating coating with high emission in the atmospheric window, by weight, the main material of the transparent heat-insulating coating is composed of the following components: 50 parts of styrene-acrylic emulsion, nano-indium tin oxide (particle diameter is 5-60nm ) 7 parts, 8 parts of nano-antimony-doped tin dioxide (with a particle size of 5-60nm), 15 parts of nano-mullite powder (with a particle size of 5-60nm), 2.5 parts of sodium hexametaphosphate as an anionic dispersant , 5 parts of DP270 dispersant as a non-ionic dispersant, 1 part of 090 defoamer, 3 parts of hydroxyethyl cellulose ether as a thickener, 0.5 parts of polypropylene oxide as a leveling agent, as a film-forming agent 1 part of alcohol ester-12 as auxiliary agent, 1 part of propylene glycol as antifreeze, and 6 parts of distilled water.

Its preparation method is to carry out following steps successively:

1), Premix:

Add 6 parts of distilled water, 2.5 parts of sodium hexametaphosphate, 5 parts of DP270 dispersant and 0.3 part of 090 defoamer in sequence under low-speed stirring (300-400r/min), and stir well (stir for 30 minutes);

2), high-speed dispersion:

Add 8 parts of nano-antimony-doped tin dioxide, 7 parts of nano-indium tin oxide and 15 parts of nano-mullite powder in sequence to the mixture obtained in step 1), stir evenly (stirring for 30 minutes), and then add hydroxyethyl cellulose Stir 1 part of plain ether and 0.4 part of 090 defoamer evenly (stir for 30 minutes) to obtain a color paste; place the color paste in a high-speed disperser for 30 minutes (3000-4000r/min).

3) Under low-speed stirring (300-400r/min), add 1 part of alcohol ester-12, 1 part of propylene glycol and 0.5 part of polypropylene oxide to 50 parts of styrene-acrylic emulsion;

4) Add the dispersed color paste obtained in step 2) to the obtained product in step 3), then stir at a low speed (300-400r/min) for 30 minutes, add the remaining 0.3 parts of 090 defoamer and the remaining Thickener (hydroxyethyl cellulose ether) 2 parts, and through AMP-95 to adjust the pH to 9, filtered to obtain a transparent heat-insulating coating with high emission in the atmospheric window area.

Embodiment 4, a transparent heat-insulating coating with high emission in the atmospheric window, by weight, the main material of the transparent heat-insulating coating is made up of the following components: 50 parts of polyacrylate emulsion, nano antimony-doped tin dioxide (particle diameter is 5-60nm) 15 parts, nano-mullite powder (5-60nm particle size) 10 parts, nano-silica powder (5-60nm particle size) 5 parts, hexametaphosphoric acid as an anionic dispersant 2 parts of sodium, 4 parts of DP270 dispersant as a non-ionic dispersant, 1 part of 090 defoamer, 3 parts of hydroxyethyl cellulose ether as a thickener, 1 part of polypropylene oxide as a leveling agent, 1 part of alcohol ester-12 as a film-forming aid, 1 part of propylene glycol as an antifreeze, and 7 parts of distilled water.

Its preparation method is to carry out following steps successively:

1), Premix:

Add 7 parts of distilled water, 2 parts of sodium hexametaphosphate, 4 parts of DP270 dispersant and 0.3 part of 090 defoamer in sequence under low-speed stirring (300-400r/min), and stir well (stir for 30 minutes);

2), high-speed dispersion:

In the mixture obtained in step 1), 15 parts of nano-antimony-doped tin dioxide, 10 parts of nano-mullite powder, and 5 parts of nano-silica powder were sequentially added, and after stirring evenly (stirring for 30 minutes), adding hydroxyethyl 1 part of base cellulose ether and 0.4 part of 090 defoamer were stirred evenly (stirring for 30 minutes) to obtain a color paste; the color paste was dispersed in a high-speed disperser for 30 minutes (3000-4000r/min).

3) Under low-speed stirring (300-400r/min), add 1 part of alcohol ester-12, 1 part of propylene glycol and 1 part of polypropylene oxide to 50 parts of polyacrylate emulsion;

4) Add the dispersed color paste obtained in step 2) to the obtained product in step 3), then stir at a low speed (300-400r/min) for 30 minutes, add the remaining 0.3 parts of 090 defoamer and the remaining Thickener (hydroxyethyl cellulose ether) 2 parts, and through AMP-95 to adjust the pH to 9, filtered to obtain a transparent heat-insulating coating with high emission in the atmospheric window area.

Comparative example 1, a kind of high-emissive transparent heat-insulating coating in the atmospheric window area, by weight, in the component of the main ingredient of its transparent heat-insulating coating: replace 15 parts of nano-molecules with 15 parts of nano-antimony-doped tin dioxide Come stone powder; That is, the total consumption of nano-antimony-doped tin dioxide is 30 parts; The rest are the same as in Example 1.

Tested by an ultraviolet-visible-near-infrared spectrophotometer, the visible light transmittance of the coating prepared by the transparent heat-insulating coating obtained in Examples 1, 2, 3, and 4 is greater than or equal to 80%, and the transmittance in the infrared region with a wavelength of 1000-2500nm Less than 10%, tested according to the JC/T235-2008 standard, the full-spectrum hemispherical emissivity of the atmospheric window area is greater than or equal to 0.8. The transparent heat-insulating coatings are all transparent, that is, after being applied to the surface of an object according to a conventional thickness, the object can be seen clearly through the coating layer.

Tested by an ultraviolet-visible-near-infrared spectrophotometer, the visible light transmittance of the coating prepared by the transparent heat-insulating coating obtained in Comparative Example 1 is 80% to 85%, and the transmittance in the infrared region with a wavelength of 1000-2500nm is less than 10%. Tested according to the JC/T235-2008 standard, the full-spectrum hemispherical emissivity of the atmospheric window area is only 0.45.

Finally, it should be noted that the above examples are only some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and many variations are possible. All deformations that can be directly derived or associated by those skilled in the art from the content disclosed in the present invention should be considered as the protection scope of the present invention.

Claims (2)

1. the transparent heat insulating dope of atmospheric window zone high emission, the major ingredient that it is characterized in that transparent heat insulating dope is grouped into by the one-tenth of following weight part: 5 ~ 20 parts of 30 ~ 70 parts of polymer emulsions, 10 ~ 30 parts of mixed nanometer oxidate powders, 2 ~ 30 parts of the nano-powders of atmospheric window oral region high emission, 1 ~ 10 part of anionic dispersing agent, 2 ~ 20 parts of non-ionic dispersing agents, 0.5 ~ 2 part of defoamer, 0 ~ 5 part of thickening material, 1 ~ 2 part of film coalescence aid, 1 ~ 2 part of frostproofer, 1 ~ 2 part of flow agent and distilled water;

Described polymer emulsion is polyacrylate dispersion, benzene emulsion or organosilicon crylic acid latex;

Described mixed nanometer oxidate powder is that particle size range is at least a in 5 ~ 60nm antimony-doped stannic oxide, fluorine-doped tin dioxide, gallium-doped zinc oxide, Al-Doped ZnO and the tin indium oxide;

The nano-powder of described atmospheric window zone high emission be particle size range be 5 ~ 60nm silicon-dioxide, mullite powder, silicon carbide, aluminum oxide and aluminosilicate at least a;

Described anionic dispersing agent is Sodium hexametaphosphate 99, tripoly phosphate sodium STPP or polymer-type anionic dispersing agent; Described non-ionic dispersing agent is dispersion agent DP270;

Described defoamer is 090 defoamer, SPA-202 defoamer, Dapro DF 7010 defoamers or tributyl phosphate;

Described thickening material is hydroxyethyl ether cellulose;

Described film coalescence aid is alcohol ester-12;

Described frostproofer is propylene glycol;

Described flow agent is poly(propylene oxide).

2. the preparation method of the transparent heat insulating dope of atmospheric window zone high emission as claimed in claim 1 is characterized in that may further comprise the steps successively:

1) defoamer that, is sequentially added into distilled water, anionic dispersing agent, non-ionic dispersing agent, 25 ~ 35% weight ratios under stirring at low speed stirs;

2) nano-powder that, in the mixture of step 1) gained, adds successively mixed nanometer oxidate powder and atmospheric window oral region high emission, after stirring, add again the thickening material of 1/2 ~ 1/4 weight ratio and the defoamer of 35 ~ 45% weight ratios and stir, get mill base; Place high speed dispersor to disperse 30 minutes mill base;

3), under the state of stirring at low speed, film coalescence aid, frostproofer and flow agent are joined in the polymer emulsion;

4), with step 2) mill base adds in the step 3) gains after the dispersion of gained, then stirring at low speed, drip residue defoamer and remaining thickening material in the whipping process, and regulate pH to 8.5 ~ 9.5 with multifunctional assistant AMP-95, get the transparent heat insulating dope of atmospheric window zone high emission.

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