A waterborne heat-insulating coating based on modified barium sulfate and its preparation method

Abstract

The present invention discloses an aqueous heat-insulating coating based on modified barium sulfate and a preparation method thereof. The aqueous heat-insulating coating comprises the following components in mass fractions: 30% - 35% of polymer emulsion, 20% - 25% of barium sulfate powder modified by zirconia, 1% - 1.5% of alcohol ester 12, 0.5% - 1% of dispersant, 0.5% - 1% of leveling agent, 0.5% - 1% of defoaming agent, and 40% - 45% of deionized water. The preparation method is to first add the modified barium sulfate powder and the dispersant into deionized water, stir and disperse evenly under ultrasonic conditions, then sequentially add the polymer emulsion, alcohol ester 12, leveling agent and defoaming agent, continue to stir evenly, and then perform degassing treatment to obtain the aqueous heat-insulating coating. The aqueous heat-insulating coating obtained by the present invention not only has simple construction operation, but also has good heat-insulating effect, and reduces the heat absorption performance of the coating itself and the heat energy release at night.

Description

Technical Field

[0001] The present invention belongs to the technical field of waterborne heat-insulating coatings, and particularly relates to a waterborne heat-insulating coating based on modified barium sulfate and a preparation method thereof. Background Art

[0002] Heat-insulating materials can improve the heat-insulating performance of building envelopes, thereby playing a role in reducing building energy consumption. However, traditional heat-insulating coatings can only delay the ingress of heat, absorb heat themselves, and release heat energy at night, which is likely to form the urban heat island effect. Therefore, improving existing heat-insulating materials to avoid causing the urban heat island effect is a current research hotspot for heat-insulating materials. At the same time, waterborne coatings use water as a solvent, contain low VOC (Volatile Organic Compound), and have the characteristics of safety, low toxicity, small odor, non-flammability, easy cleaning, and environmental protection. They are environmentally friendly coatings advocated by the country at present. Therefore, waterborne heat-insulating coatings that can be used for painting exterior and interior walls of buildings have also become one of the important research directions, requiring that waterborne heat-insulating coatings can not only improve the heat-insulating and heat-preserving performance of buildings but also alleviate the urban heat island effect. Summary of the Invention

[0003] In view of the above deficiencies, the present invention discloses a waterborne heat-insulating coating based on modified barium sulfate and a preparation method thereof. The obtained waterborne heat-insulating coating not only has simple construction operation but also has good heat-insulating effect, and reduces the heat absorption performance of the coating itself and the heat energy release at night.

[0004] The present invention is realized by the following technical solutions:

[0005] A waterborne heat-insulating coating based on modified barium sulfate, which comprises the following components in mass fractions: 30% - 35% of polymer emulsion, 20% - 25% of modified barium sulfate powder, 1% - 1.5% of alcohol ester twelve (dodecyl alcohol ester), 0.5% - 1% of dispersant, 0.5% - 1% of leveling agent, 0.5% - 1% of defoaming agent, and 40% - 45% of deionized water; the polymer emulsion is any one or a combination of two of acrylic emulsion and silicone-acrylic emulsion;

[0006] The preparation method of the modified barium sulfate powder comprises the following steps:

[0007] S1. Weigh ZrO2 powder (zirconia powder), add it to deionized water, and disperse it evenly by ultrasonic treatment. Then add sodium stearate and stir for 1 h under the condition of a 70 °C water bath to obtain a zirconia feed liquid. The mass ratio of sodium stearate to ZrO2 powder is 3:100. Weigh BaSO4 powder (barium sulfate powder), add it to deionized water, and disperse it evenly by ultrasonic treatment. Then add sodium stearate and stir for 1 h under the condition of a 70 °C water bath to obtain a barium sulfate feed liquid. The mass ratio of sodium stearate to BaSO4 powder is 3:100.

[0008] S2. Mix the barium sulfate feed liquid and the zirconia feed liquid obtained in step S1, then add a 1% NaOH solution by mass fraction to adjust the pH value to 9 - 10, continue stirring for 1 h, and then perform suction filtration to obtain a precipitate. After drying and grinding the precipitate, calcine it at 400 °C for 2 h, and then ball-mill the calcined powder for 30 min to obtain modified barium sulfate powder. In the modified barium sulfate powder, the proportion of ZrO2 powder is 2.5% - 7.5%.

[0009] In the present invention, sodium stearate is first used to perform surface modification on BaSO4 powder and ZrO2 powder respectively, so that the surfaces of BaSO4 powder and ZrO2 powder have hydrophobicity. Then, the two are mixed and by adjusting the pH value, ZrO2 is attached to the surface of BaSO4. Then, through high-temperature calcination, sodium stearate decomposes, forming defects on the surface of the ZrO2-modified BaSO4 powder, improving the reflection and scattering of the barium sulfate powder to solar radiation. Uniformly adding it to the water-based coating can effectively improve the heat insulation effect of the water-based coating.

[0010] Further, in step S1, the stirring speed is 1000 r / min.

[0011] Further, in step S1, the polymer emulsion is obtained by mixing acrylic emulsion and silicone-acrylic emulsion in a volume ratio of 1:2.

[0012] Further, in step S2, add a 1% NaOH solution by mass fraction to adjust the pH value to 9 - 10, and continue stirring for 1 h at a speed of 1000 r / min, and then perform suction filtration to obtain a precipitate.

[0013] Further, in step S2, the drying temperature is 70 °C.

[0014] Further, the dispersant includes any one of X-405, Genapol ED3060, COATEX A122, COADIS 123K, and Hydropalat306; the leveling agent includes any one of XYS-5360, Hydropalat3070, BYK341, and EFKA-3580; the defoamer includes any one of Silok4600, DAPRO DF7580, DEE FO3030, DREWPLUS T-4201, and Suefynol DF695.

[0015] The preparation method of the above waterborne heat-insulating coating based on modified barium sulfate is to first weigh the modified barium sulfate powder and the dispersant and add them to deionized water in sequence. Under the conditions of ultrasonic wave and a stirring speed of 1000 r / min, stir and disperse evenly to obtain a slurry. Then, add the polymer emulsion, 2-ethylhexyl acetate, leveling agent, and defoamer to the slurry in sequence, continue to stir evenly, and then perform ultrasonic degassing treatment to obtain the waterborne heat-insulating coating. The prepared waterborne heat-insulating coating can be coated on the substrate by spraying or brushing, and after drying, a coating is formed, and the coating thickness is controlled at 180-220 μm.

[0016] The beneficial effects of this technical solution compared with the prior art are as follows:

[0017] Barium sulfate has a relatively high electron band gap and a phonon resonance of 9 μm, which makes the barium sulfate powder have a low sunlight absorption rate and a high reflectivity. However, currently, barium sulfate is only added to the coating as a filler or a whitening pigment, and the improvement effect on the heat-insulating performance of the coating is not good. Therefore, in the present invention, the barium sulfate powder is modified to obtain modified barium sulfate powders with different structures, so as to achieve the effect of improving the performance of barium sulfate. Adding the modified barium sulfate powder to the coating (as shown in Figure 13 ) can obtain a good heat-insulating effect, thereby reducing the temperature of the substrate. Description of the Drawings

[0018] Figure 1 is the infrared spectrogram of barium sulfate powder, zirconia powder, and the modified barium sulfate powder described in Example 1, where curve 1 is the zirconia powder, curve 2 is the barium sulfate powder, and curve 3 is the modified barium sulfate powder.

[0019] Figure 2 is the SEM picture of the barium sulfate powder described in Comparative Example 1.

[0020] Figure 3 is the SEM picture of the zirconia powder described in Comparative Example 2.

[0021] Figure 4 is the SEM picture of the modified barium sulfate powder described in Example 1.

[0022] Figure 5 It is the SEM picture of the surface of the coating obtained in Example 1.

[0023] Figure 6 It is the SEM picture of the surface of the coating obtained in Comparative Example 1.

[0024] Figure 7 It is the SEM picture of the surface of the coating obtained in Comparative Example 2.

[0025] Figure 8 It is the SEM picture of the surface of the coating obtained in Comparative Example 3.

[0026] Figure 9 It is the SEM picture of the cross-section of the coating obtained in Example 1.

[0027] Figure 10 It is the SEM picture of the cross-section of the coating obtained in Comparative Example 1.

[0028] Figure 11 It is the SEM picture of the cross-section of the coating obtained in Comparative Example 2.

[0029] Figure 12 It is the SEM picture of the cross-section of the coating obtained in Comparative Example 3.

[0030] Figure 13 It is the structural schematic diagram of the coating obtained by the method of the present invention, wherein label 1 is barium sulfate, label 2 is zirconia, label 3 represents incidence, label 4 represents reflection, and label 5 represents radiation. Embodiment

[0031] The present invention will be further illustrated by the following examples, which shall not be construed as limiting the present invention. For the specific experimental conditions and methods not specified in the following examples, the technical means adopted are usually conventional means well known to those skilled in the art.

[0032] Example 1: An aqueous heat-insulating coating based on modified barium sulfate, which comprises the following components in mass fractions: polymer emulsion 32.5%, modified barium sulfate powder 21.5%, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate 1.3%, dispersant 0.7%, leveling agent 0.6%, defoaming agent 0.6%, deionized water 42.8%; the polymer emulsion is obtained by mixing acrylic emulsion and silicone-acrylic emulsion in a volume ratio of 1:2;

[0033] The preparation method of the modified barium sulfate powder comprises the following steps:

[0034] S1. Weigh ZrO2 powder and add it to deionized water, then ultrasonically disperse it evenly. Next, add sodium stearate and treat it for 1 h in a 70 °C water bath with a stirring speed of 1000 r / min to obtain a zirconia feed solution. The mass ratio of sodium stearate to ZrO2 powder is 3:100. Weigh BaSO4 powder and add it to deionized water, then ultrasonically disperse it evenly. Next, add sodium stearate and treat it for 1 h in a 70 °C water bath with a stirring speed of 1000 r / min to obtain a barium sulfate feed solution. The mass ratio of sodium stearate to BaSO4 powder is 3:100.

[0035] S2. Mix the barium sulfate feed solution and the zirconia feed solution obtained in step S1, then add a 1% NaOH solution to adjust the pH value to 9.5. Continue to stir for 1 h at a speed of 1000 r / min and then filter to obtain a precipitate. First, dry the precipitate at 70 °C, then grind it and calcine it at 400 °C for 2 h. Ball-mill the calcined powder for 30 min to obtain modified barium sulfate powder. In the modified barium sulfate powder, the proportion of ZrO2 powder is 5%. The dispersant is Hydropalat 306. The leveling agent is EFKA-3580. The defoaming agent is Silok 4600.

[0036] The preparation method of the waterborne heat-insulating coating based on modified barium sulfate in this example is to first weigh the modified barium sulfate powder and the dispersant and add them to deionized water in turn. Stir and disperse them evenly under ultrasonic conditions with a stirring speed of 1000 r / min to obtain a slurry. Then, add a polymer emulsion, lauryl alcohol ester, a leveling agent, and a defoaming agent to the slurry in turn, continue to stir evenly, and then perform ultrasonic degassing treatment to obtain a waterborne heat-insulating coating. The prepared waterborne heat-insulating coating can be applied to the substrate by spraying or brushing, and a coating is formed after drying. The thickness of the coating is controlled at 210 μm.

[0037] Example 2: A waterborne heat-insulating coating based on modified barium sulfate, which comprises the following components by mass fraction: 30% polymer emulsion, 25% modified barium sulfate powder, 1% lauryl alcohol ester, 0.5% dispersant, 0.5% leveling agent, 0.5% defoaming agent, 42.5% deionized water. The polymer emulsion is an acrylic emulsion.

[0038] The preparation method of the modified barium sulfate powder comprises the following steps:

[0039] S1. Weigh ZrO₂ powder and add it to deionized water, then ultrasonically disperse it evenly. Next, add sodium stearate and treat it for 1 h in a 70 °C water bath with a stirring speed of 1000 r / min to obtain a zirconia feed liquid. The mass ratio of sodium stearate to ZrO₂ powder is 3:100. Weigh BaSO₄ powder and add it to deionized water, then ultrasonically disperse it evenly. Next, add sodium stearate and treat it for 1 h in a 70 °C water bath with a stirring speed of 1000 r / min to obtain a barium sulfate feed liquid. The mass ratio of sodium stearate to BaSO₄ powder is 3:100.

[0040] S2. Mix the barium sulfate feed liquid and the zirconia feed liquid obtained in step S1, then add a 1% NaOH solution to adjust the pH value to 9. Continue to stir for 1 h at a speed of 1000 r / min and then filter to obtain a precipitate. First, dry the precipitate at 70 °C, then grind it and calcine it at 400 °C for 2 h. Ball-mill the calcined powder for 30 min to obtain modified barium sulfate powder. In the modified barium sulfate powder, the proportion of ZrO₂ powder is 2.5%. The dispersant is X-405. The leveling agent is XYS-5360. The defoaming agent is DAPRO DF7580.

[0041] The preparation method of the waterborne heat-insulating coating based on modified barium sulfate in this example is to first weigh the modified barium sulfate powder and the dispersant and add them to deionized water in sequence. Stir and disperse them evenly under ultrasonic conditions with a stirring speed of 1000 r / min to obtain a slurry. Then, add polymer emulsion, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, leveling agent, and defoaming agent to the slurry in sequence, continue to stir evenly, and then perform ultrasonic degassing treatment to obtain the waterborne heat-insulating coating. The prepared waterborne heat-insulating coating can be coated on the substrate by spraying or brushing, and a coating is formed after drying. The coating thickness is controlled at 180 μm.

[0042] Example 3: A waterborne heat-insulating coating based on modified barium sulfate, which comprises the following components by mass fraction: polymer emulsion 35%, modified barium sulfate powder 20%, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate 1.5%, dispersant 1%, leveling agent 1%, defoaming agent 1%, deionized water 40.5%. The polymer emulsion is a silicone-acrylic emulsion.

[0043] The preparation method of the modified barium sulfate powder comprises the following steps:

[0044] S1. Weigh ZrO₂ powder, add it to deionized water, and ultrasonically disperse it evenly. Then add sodium stearate and treat it for 1 h in a 70 °C water bath with a stirring speed of 1000 r / min to obtain a zirconia feed solution. The mass ratio of sodium stearate to ZrO₂ powder is 3:100. Weigh BaSO₄ powder, add it to deionized water, and ultrasonically disperse it evenly. Then add sodium stearate and treat it for 1 h in a 70 °C water bath with a stirring speed of 1000 r / min to obtain a barium sulfate feed solution. The mass ratio of sodium stearate to BaSO₄ powder is 3:100.

[0045] S2. Mix the barium sulfate feed solution and the zirconia feed solution obtained in step S1. Then add a 1% NaOH solution to adjust the pH value to 10. Continue to stir for 1 h at a speed of 1000 r / min and then filter to obtain a precipitate. First, dry the precipitate at 70 °C, then grind it and calcine it at 400 °C for 2 h. Ball-mill the calcined powder for 30 min to obtain modified barium sulfate powder. In the modified barium sulfate powder, the proportion of ZrO₂ powder is 7.5%. The dispersant is Genapol ED3060. The leveling agent is Hydropalat 3070. The defoaming agent is DREWPLUS T-4201.

[0046] The preparation method of the waterborne heat-insulating coating based on modified barium sulfate in this example is to first weigh the modified barium sulfate powder and the dispersant and add them to deionized water in turn. Stir and disperse them evenly under ultrasonic conditions with a stirring speed of 1000 r / min to obtain a slurry. Then add polymer emulsion, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, leveling agent, and defoaming agent to the slurry in turn, continue to stir evenly, and then perform ultrasonic degassing treatment to obtain a waterborne heat-insulating coating. The prepared waterborne heat-insulating coating can be applied to the substrate by spraying or brushing, and a coating is formed after drying. The coating thickness is controlled at 220 μm.

[0047] Example 4: A waterborne heat-insulating coating based on modified barium sulfate, which comprises the following components in mass fraction: polymer emulsion 31%, modified barium sulfate powder 21.5%, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate 1%, dispersant 0.5%, leveling agent 0.5%, defoaming agent 0.5%, deionized water 45%.

[0048] The preparation method of the modified barium sulfate powder comprises the following steps:

[0049] S1. Weigh ZrO2 powder and add it to deionized water, then ultrasonically disperse it evenly. Then add sodium stearate and treat it for 1 h in a 70 °C water bath with a stirring speed of 1000 r / min to obtain a zirconia slurry. The mass ratio of sodium stearate to ZrO2 powder is 3:100. Weigh BaSO4 powder and add it to deionized water, then ultrasonically disperse it evenly. Then add sodium stearate and treat it for 1 h in a 70 °C water bath with a stirring speed of 1000 r / min to obtain a barium sulfate slurry. The mass ratio of sodium stearate to BaSO4 powder is 3:100.

[0050] S2. Mix the barium sulfate slurry and zirconia slurry obtained in step S1, then add a 1% NaOH solution to adjust the pH value to 9. Continue to stir for 1 h at a speed of 1000 r / min and then filter to obtain a precipitate. First, dry the precipitate at 70 °C, then grind it and calcine it at 400 °C for 2 h. Ball-mill the calcined powder for 30 min to obtain modified barium sulfate powder. In the modified barium sulfate powder, the proportion of ZrO2 powder is 5%. The dispersant is COADIS 123K. The leveling agent is BYK341. The defoaming agent is DEE FO3030.

[0051] The preparation method of the waterborne heat-insulating coating based on modified barium sulfate in this example is to first weigh the modified barium sulfate powder and the dispersant and add them to deionized water in turn. Stir and disperse them evenly under ultrasonic conditions with a stirring speed of 1000 r / min to obtain a slurry. Then add polymer emulsion, 2-ethylhexyl acetate, leveling agent and defoaming agent to the slurry in turn, continue to stir evenly, and then perform ultrasonic degassing treatment to obtain the waterborne heat-insulating coating. The prepared waterborne heat-insulating coating can be coated on the substrate by spraying or brushing, and a coating is formed after drying. The thickness of the coating is controlled at 220 μm.

[0052] Example 5: A waterborne heat-insulating coating based on modified barium sulfate, which comprises the following components by mass fraction: polymer emulsion 32%, modified barium sulfate powder 23.5%, 2-ethylhexyl acetate 1.5%, dispersant 1%, leveling agent 1%, defoaming agent 1%, deionized water 40%.

[0053] The preparation method of the modified barium sulfate powder comprises the following steps:

[0054] S1. Weigh ZrO₂ powder and add it to deionized water, then ultrasonically disperse it evenly. Next, add sodium stearate and treat it for 1 h in a 70 °C water bath with a stirring speed of 1000 r / min to obtain a zirconia feed liquid. The mass ratio of sodium stearate to ZrO₂ powder is 3:100. Weigh BaSO₄ powder and add it to deionized water, then ultrasonically disperse it evenly. Next, add sodium stearate and treat it for 1 h in a 70 °C water bath with a stirring speed of 1000 r / min to obtain a barium sulfate feed liquid. The mass ratio of sodium stearate to BaSO₄ powder is 3:100.

[0055] S2. Mix the barium sulfate feed liquid and the zirconia feed liquid obtained in step S1. Then add a 1% NaOH solution to adjust the pH value to 9.5. Continue to stir for 1 h at a speed of 1000 r / min and then filter to obtain a precipitate. First, dry the precipitate at 70 °C, then grind it and calcine it at 400 °C for 2 h. Ball-mill the calcined powder for 30 min to obtain modified barium sulfate powder. In the modified barium sulfate powder, the proportion of ZrO₂ powder is 5%. The dispersant is COADIS 123K. The leveling agent is EFKA-3580. The defoaming agent is Suefynol DF695.

[0056] In this example, the preparation method of the waterborne heat-insulating coating based on modified barium sulfate is to first weigh the modified barium sulfate powder and the dispersant and add them to deionized water in turn. Stir and disperse them evenly under ultrasonic conditions with a stirring speed of 1000 r / min to obtain a slurry. Then, add polymer emulsion, lauryl alcohol ester, leveling agent, and defoaming agent to the slurry in turn, continue to stir evenly, and then perform ultrasonic degassing treatment to obtain the waterborne heat-insulating coating. The prepared waterborne heat-insulating coating can be coated on the substrate by spraying or brushing, and a coating is formed after drying. The thickness of the coating is controlled at 220 μm.

[0057] Comparative Example 1: The waterborne heat-insulating coating in this comparative example includes the following components by mass fraction: polymer emulsion 32.5%, barium sulfate powder 21.5%, lauryl alcohol ester 1.3%, dispersant 0.7%, leveling agent 0.6%, defoaming agent 0.6%, deionized water 42.8%. The polymer emulsion is obtained by mixing acrylic emulsion and silicone-acrylic emulsion in a volume ratio of 1:2. The dispersant is Hydropalat306. The leveling agent is EFKA-3580. The defoaming agent is Silok4600.

[0058] The preparation method of the waterborne heat-insulating coating described in this comparative example is to first weigh barium sulfate powder and a dispersant and sequentially add them to deionized water, and stir and disperse evenly to obtain a slurry under the conditions of ultrasonic wave and a stirring speed of 1000 r / min. Then, a polymer emulsion, lauryl acetate, a leveling agent, and an antifoaming agent are sequentially added to the slurry, and stirring is continued until evenly mixed. Then, ultrasonic degassing treatment is carried out to obtain the waterborne heat-insulating coating. The prepared waterborne heat-insulating coating can be coated on the substrate by spraying or brushing, and a coating is formed after drying, and the coating thickness is controlled at 210 μm.

[0059] Comparative Example 2: The waterborne heat-insulating coating described in this comparative example comprises the following components by mass fraction: 32.5% of polymer emulsion, 21.5% of zirconia powder, 1.3% of lauryl acetate, 0.7% of dispersant, 0.6% of leveling agent, 0.6% of antifoaming agent, and 42.8% of deionized water; the polymer emulsion is obtained by mixing an acrylic emulsion and a silicone-acrylic emulsion in a volume ratio of 1:2; the dispersant is Hydropalat 306; the leveling agent is EFKA-3580; the antifoaming agent is Silok 4600.

[0060] The preparation method of the waterborne heat-insulating coating described in this comparative example is to first weigh zirconia powder and a dispersant and sequentially add them to deionized water, and stir and disperse evenly to obtain a slurry under the conditions of ultrasonic wave and a stirring speed of 1000 r / min. Then, a polymer emulsion, lauryl acetate, a leveling agent, and an antifoaming agent are sequentially added to the slurry, and stirring is continued until evenly mixed. Then, ultrasonic degassing treatment is carried out to obtain the waterborne heat-insulating coating. The prepared waterborne heat-insulating coating can be coated on the substrate by spraying or brushing, and a coating is formed after drying, and the coating thickness is controlled at 210 μm.

[0061] Comparative Example 3: The waterborne heat-insulating coating described in this comparative example comprises the following components by mass fraction: 32.5% of polymer emulsion, 21.5% of mixed powder, 1.3% of lauryl acetate, 0.7% of dispersant, 0.6% of leveling agent, 0.6% of antifoaming agent, and 42.8% of deionized water; the mixed powder is obtained by mixing zirconia powder and barium sulfate powder in a mass ratio of 5:100; the polymer emulsion is obtained by mixing an acrylic emulsion and a silicone-acrylic emulsion in a volume ratio of 1:2; the dispersant is Hydropalat 306; the leveling agent is EFKA-3580; the antifoaming agent is Silok 4600.

[0062] The preparation method of the waterborne heat-insulating coating described in this comparative example is to first weigh the mixed powder and the dispersant and add them to deionized water in sequence. Under the conditions of ultrasonic wave and a stirring speed of 1000 r / min, stir and disperse evenly to obtain a slurry. Then, add the polymer emulsion, 2-ethylhexyl acetate, leveling agent and defoamer to the slurry in sequence, continue to stir evenly, and then perform ultrasonic degassing treatment to obtain the waterborne heat-insulating coating. The prepared waterborne heat-insulating coating can be coated on the substrate by spraying or brushing, and a coating is formed after drying, and the coating thickness is controlled at 210 μm.

[0063] Experimental Example 1: Prepare the waterborne heat-insulating coating according to the methods described in Examples 1 to 5 and Comparative Examples 1 to 3, and prepare test plates according to the method in the standard HG∕T 4341-2012 "Thermal Reflection Coating for Metal Surfaces", and at the same time make a blackboard as a reference sample. Control the temperature of the back of the blackboard to be 70 ± 1 °C, and then replace the blackboard with the test plate, and calculate the heat-insulating temperature difference from the reference blackboard according to the following formula: △T = T0-T i , where:

[0064] △T represents the value of the heat-insulating temperature difference from the reference blackboard, with the unit of °C; T0 represents the value of the average temperature of the back of the reference blackboard, with the unit of °C; T i represents the value of the average temperature of the back of the test plate, with the unit of °C. The test results are shown in Table 1.

[0065] Table 1 Test Results of Different Waterborne Heat-Insulating Coatings

[0066]

[0067] It can be seen from the data in Table 1 that the coating formed by using the coating prepared according to the method of the present invention has better heat-insulating effect, because according to Figures 1 to 12 it can be known that the modified barium sulfate powder prepared according to the method of the present invention has obvious differences in structure from barium sulfate powder and zirconia powder, and the coating formed by using the coating with the modified barium sulfate powder of the present invention is compared with the coating obtained by using barium sulfate powder or zirconia powder alone and their mixed powder, there are obvious structural differences. The structure of the modified barium sulfate powder prepared by the method of the present invention can improve its performance after being applied to the coating, which makes the heat-insulating effect obtained by the coating also different.

[0068] Experimental Example 2: Prepare modified barium sulfate powders with different proportions of zirconia powder according to the method described in Example 1. In the modified barium sulfate powder, the content of zirconia powder is 1%, 2.5%, 5%, 7.5%, 10% respectively;

[0069] According to the method of the present invention, different modified barium sulfate powder is added to prepare the waterborne heat-insulating coating. Specifically, 5 g of modified barium sulfate powder and 0.15 g of dispersant are weighed and added to 10 mL of deionized water, and stirred and dispersed evenly under ultrasonic conditions to obtain a slurry. Then, 7.5 g of acrylic emulsion, 0.3 g of lauryl alcohol ester, 0.15 g of leveling agent and 0.15 g of defoaming agent are added to the slurry in sequence, and stirred evenly. Then, degassing treatment is carried out to obtain the waterborne heat-insulating coating;

[0070] The obtained waterborne heat-insulating coating is tested according to the method described in Experimental Example 1, and the test results are shown in Table 2.

[0071] Table 2 Test results of waterborne heat-insulating coatings with different modified barium sulfate powders

[0072]

[0073] It can be seen from the data in Table 2 that the modified barium sulfate powder obtained by modifying barium sulfate powder with zirconia according to the method of the present invention has better performance, and adding it to the coating can improve its heat-insulating effect. However, the dosage ratio of zirconia and barium sulfate powder needs to be strictly controlled. Excessive use of zirconia powder will change the structure of the modified barium sulfate powder and reduce its performance.

[0074] In addition, it should be understood that although this specification is described according to the embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A waterborne heat-insulating coating based on modified barium sulfate, characterized in that: It comprises components with the following mass fractions: 30% - 35% of polymer emulsion, 20% - 25% of modified barium sulfate powder, 1% - 1.5% of alcohol ester 12, 0.5% - 1% of dispersant, 0.5% - 1% of leveling agent, 0.5% - 1% of defoamer, and 40% - 45% of deionized water; the polymer emulsion is any one or a combination of two of acrylic emulsion and silicon-acrylic emulsion; The preparation method of the said modified barium sulfate powder comprises the following steps: S1. Weigh ZrO2 powder and add it to deionized water, then ultrasonically disperse it evenly. Next, add sodium stearate and stir it for 1 h under the condition of a 70 °C water bath to obtain zirconia stock solution. The mass ratio of sodium stearate to ZrO2 powder is 3:100; weigh BaSO4 powder and add it to deionized water, then ultrasonically disperse it evenly. Next, add sodium stearate and stir it for 1 h under the condition of a 70 °C water bath to obtain barium sulfate stock solution. The mass ratio of sodium stearate to BaSO4 powder is 3:100; S2. Mix the barium sulfate stock solution and zirconia stock solution obtained in step S1, then add a 1% NaOH solution by mass fraction to adjust the pH value to 9 - 10, continue stirring for 1 h, then filter to obtain a precipitate. After drying and grinding the precipitate, calcine it at 400 °C for 2 h, and ball-mill the calcined powder for 30 min to obtain the modified barium sulfate powder. In the said modified barium sulfate powder, the proportion of ZrO2 powder is 2.5% - 7.5%.

2. The waterborne heat-insulating coating based on modified barium sulfate according to claim 1, wherein: In step S1, the stirring speed is 1000 r / min.

3. The waterborne heat-insulating coating based on modified barium sulfate according to claim 1, wherein: In step S1, the polymer emulsion is obtained by mixing acrylic emulsion and silicon-acrylic emulsion in a volume ratio of 1:

2.

4. The waterborne heat-insulating coating based on modified barium sulfate according to claim 1, wherein: In step S2, add a 1% NaOH solution by mass fraction to adjust the pH value to 9 - 10, continue stirring for 1 h at a speed of 1000 r / min, then filter to obtain a precipitate.

5. The waterborne heat-insulating coating based on modified barium sulfate according to claim 1, characterized in that: In step S2, the drying temperature is 70 °C.

6. The water-based heat-insulating coating based on modified barium sulfate according to claim 1, wherein: The said dispersant includes any one of X-405, Genapol ED3060, COATEX A122, COADIS 123K, and Hydropalat306; the said leveling agent includes any one of XYS-5360, Hydropalat3070, BYK341, and EFKA-3580; the said defoamer includes any one of Silok4600, DAPRO DF7580, DEE FO3030, DREWPLUS T-4201, and Suefynol DF695.

7. The preparation method of the water-based heat-insulating coating based on modified barium sulfate according to any one of claims 1 to 6, characterized in that: The said preparation method is to first weigh the modified barium sulfate powder and the dispersant and add them to deionized water in sequence, stir and disperse them evenly under the conditions of ultrasonic wave and a stirring speed of 1000 r / min to obtain a slurry. Then, add the polymer emulsion, alcohol ester 12, leveling agent, and defoamer to the slurry in sequence, continue to stir evenly, and then perform ultrasonic degassing treatment to obtain the water-based heat-insulating coating.

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