Radiant reflective heat shield coating and method of making same

Abstract

The application discloses a preparation method of a radiation type reflective heat insulation coating, which is composed of the following raw materials: reflective heat insulation fillers, radiation heat insulation fillers, water-based film forming substances, barrier type heat insulation fillers, dispersants, defoaming agents, thickening agents, deionized water and heavy calcium powder. The radiation type reflective heat insulation coating prepared by the application adopts self-made flower-like rutile titanium dioxide as the reflective filler, and the flower-like titanium dioxide has a larger surface area to reflect sunlight; metal oxides which are beneficial to promoting the transformation of titanium dioxide from the anatase crystal type to the rutile crystal type with higher reflectivity are added in the preparation process; and the prepared radiation type reflective heat insulation coating has good infrared radiation performance in each wave band of the atmospheric window.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of thermal insulation coatings, and particularly relates to a preparation method of a radiation type reflective thermal insulation coating. BACKGROUND

[0002] With the development of economy, the proportion of building energy consumption is also increasing, and the use of thermal insulation coatings can effectively reduce building energy consumption and plays a huge role in the field of building energy saving. At present, thermal insulation coatings are mainly divided into reflective thermal insulation coatings, barrier thermal insulation coatings and radiation thermal insulation coatings. Reflective thermal insulation coatings insulate heat outside the building by efficiently reflecting sunlight, and the most commonly used reflective functional filler is titanium dioxide, which has strong hiding power, and titanium dioxide also has high solar reflectance in the visible and near-infrared bands. Barrier thermal insulation coatings mainly rely on the addition of low thermal conductivity functional fillers to block the transfer of external heat, and radiation thermal insulation coatings rely on high-emissivity functional fillers to actively emit heat to the outside to achieve the purpose of thermal insulation. The radiation type reflective thermal insulation coating disclosed in the application is a thermal insulation coating that combines thermal radiation, heat reflection and heat barrier.

[0003] When titanium dioxide is added as a reflective functional filler to thermal insulation coatings, the reflectivity of the thermal insulation coatings will increase with the increase of the content of titanium dioxide. After reaching the optimal reflectivity, further increase of titanium dioxide will cause agglomeration and poor dispersibility. Flower-shaped titanium dioxide has a higher surface area, and its light scattering in the coating is more sufficient, which can more fully utilize the high solar reflectance characteristics of titanium dioxide. Rutile titanium dioxide has higher reflectivity, weather resistance and thermal stability than anatase titanium dioxide. The complete conversion of titanium dioxide crystal form from anatase to rutile usually requires calcination at more than 1000 degrees Celsius for a long time. After adding some metal oxides with similar ionic radii to titanium ions, the metal oxides will easily enter the titanium ions, change the lattice energy of the crystal, and cause distortion of the titanium dioxide lattice, which is more conducive to the formation of rutile titanium dioxide. Flower-shaped rutile titanium dioxide can endow the thermal insulation coating with higher solar reflectance to improve the thermal insulation performance of the coating. SUMMARY

[0004] This section aims to summarize some aspects of the embodiments of the application and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of the specification to avoid obscuring the purpose of this section, abstract and title, and such simplifications or omissions cannot be used to limit the scope of the application.

[0005] In view of the above and / or problems existing in the prior art, the present application is proposed.

[0006] Therefore, the present application aims at overcoming the deficiencies in the prior art and providing a preparation method of a radiation type reflective thermal insulation coating.

[0007] To solve the above technical problems, the present application provides the following technical scheme: a preparation method of a radiation type reflective thermal insulation coating, characterized in that it comprises,

[0008] After the tetrabutyl titanate and ethanol are fully mixed and stirred, a pH regulator is added, and after being fully mixed, it is added to a high-pressure reaction kettle, the high-pressure reaction kettle is heated to a constant temperature, and then cooled to room temperature, centrifuged, washed, and dried to obtain a reflective thermal insulation material flower-like rutile titanium dioxide;

[0009] The dried flower-like titanium dioxide is mixed with metal oxides that can promote the generation of rutile titanium dioxide and fully stirred and uniform, and then calcined to obtain a reflective thermal insulation material flower-like rutile titanium dioxide;

[0010] After the dispersant, deionized water, and water-based film-forming material are fully stirred, the reflective thermal insulation filler flower-like rutile titanium dioxide, radiation thermal insulation filler, barrier type thermal insulation filler, and heavy calcium powder are added, and then fully stirred again, the thickening agent is finally added to obtain a radiation type reflective thermal insulation coating;

[0011] Among them, the reflective thermal insulation filler flower-like rutile titanium dioxide is 10%, the radiation thermal insulation filler is 3-6%, the water-based film-forming material is 35-45%, the barrier type thermal insulation filler is 10-15%, the dispersant is 0.5-2%, the thickening agent is 0.5-2%, the deionized water is 5-15%, and the heavy calcium powder is 5-15%, all in terms of mass percentage.

[0012] As a preferred scheme of the preparation method of the present application, the reflective thermal insulation filler is self-made flower-like rutile titanium dioxide.

[0013] As a preferred scheme of the preparation method of the present application, the pH regulator is a 0.1 mol / L NaOH solution, and the pH of the solution is adjusted to 7-9.

[0014] As a preferred scheme of the preparation method of the present application, the volume ratio of tetrabutyl titanate to ethanol is 1-3:70-100.

[0015] As a preferred scheme of the preparation method of the present application, the high-pressure reaction kettle is heated to a constant temperature, the temperature is 160-200°C, and the time is ≥12 h.

[0016] As a preferred scheme of the preparation method of the present application, the calcination to obtain a reflective thermal insulation material flower-like rutile titanium dioxide is carried out at a temperature of 800°C for 2 h.

[0017] As a preferred scheme of the preparation method, the metal oxide is one or more of ferric oxide, tin dioxide, vanadium pentoxide and zinc oxide, and the total mass of the added ferric oxide, tin dioxide, vanadium pentoxide and zinc oxide is 0.3% to 0.8% of the mass fraction of the flower-shaped titanium dioxide.

[0018] As a preferred scheme of the preparation method, the radiation heat insulation filler is ferric oxide, manganese dioxide, silicon carbide, chromium trioxide and copper oxide, and the mass ratio of the ferric oxide, manganese dioxide, silicon carbide, chromium trioxide and copper oxide is 2:2:2:1:1.

[0019] As a preferred scheme of the preparation method, the water-based film-forming substance is a silicone-acrylate emulsion.

[0020] As a preferred scheme of the preparation method, the barrier type heat insulation filler is hollow glass microbeads.

[0021] As a preferred scheme of the preparation method, the dispersant is a polycarboxylate dispersant 5040 type.

[0022] Still another object of the present application is to provide a product prepared by the preparation method of the radiation type reflective heat insulation coating.

[0023] The present application has the following advantages:

[0024] (1) The radiation type reflective heat insulation coating prepared by the present application uses the self-prepared reflective heat insulation filler (flower-shaped rutile titanium dioxide), which has a larger surface area for reflecting sunlight compared with traditional titanium dioxide, and the light scattering in the coating is more sufficient, and the reflective rate is higher. The added metal oxide can promote the formation of rutile titanium dioxide at a lower calcination temperature and a shorter calcination time.

[0025] (2) The radiation type reflective heat insulation coating prepared by the present application can not only passively block heat from entering the building, but also rely on the internal high-emissivity material to radiate heat to the outside. The heat insulation coating has good emissivity in each wave band in the atmospheric window, and the heat insulation effect is much better than that of the existing heat insulation and heat preservation coatings. BRIEF DESCRIPTION OF DRAWINGS

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0027] Figure 1 This is a scanning electron microscope image of the flower-shaped rutile titanium dioxide prepared in Example 1.

[0028] Figure 2 The image shows a scanning electron microscope (SEM) image of the self-made flower-shaped rutile titanium dioxide from Comparative Example 1.

[0029] Figure 3 The image shows a scanning electron microscope (SEM) image of the self-made flower-shaped rutile titanium dioxide from Comparative Example 3.

[0030] Figure 4 The image shown is a scanning electron microscope image of the self-made flower-shaped rutile titanium dioxide from Comparative Example 4. Detailed Implementation

[0031] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0032] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0033] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0034] The hollow glass microspheres used in the following examples and comparative examples were purchased from Saint-Tropez New Materials Co., Ltd., model HL60.

[0035] Example 1

[0036] This embodiment relates to the preparation of a self-made flower-shaped rutile titanium dioxide, including the following steps:

[0037] Preparation of self-made flower-shaped rutile titanium dioxide:

[0038] (1) 2mL tetrabutyl titanate and 70mL ethanol were mixed in a beaker and stirred in a water bath for 30 minutes. Then 0.1mol / L NaOH solution was added to adjust the pH of the solution to 8. The solution was mixed thoroughly and then added to a 100mL high-pressure reaction kettle. The high-pressure reaction kettle was heated to maintain a temperature of 180℃. After 12 hours, the solution was cooled to room temperature, centrifuged, washed, and dried to obtain flower-shaped titanium dioxide.

[0039] (2) The flower-shaped titanium dioxide prepared in step (1) was mixed with metal oxides (the total mass of the added iron trioxide, tin dioxide, vanadium pentoxide, and zinc oxide was 0.5% of the mass fraction of the flower-shaped titanium dioxide) that can promote the formation of rutile titanium dioxide and stirred thoroughly. Then the mixture was placed in a muffle furnace and calcined at 800℃ for 2 hours to obtain flower-shaped rutile titanium dioxide.

[0040] The flower-shaped rutile titanium dioxide prepared in this example was used as a reflective thermal insulation filler to prepare thermal insulation coating 1.

[0041] Thermal insulation coating 1 contains the following components by mass percentage: 45% water-based film-forming resin silicone-acrylic emulsion, 10% reflective thermal insulation filler (self-made flower-shaped rutile titanium dioxide), 10% deionized water, 5% radiation thermal insulation filler (iron trioxide, manganese dioxide, silicon carbide, chromium trioxide, and copper oxide, with a mass ratio of 2:2:2:1:1), 15% barrier-type thermal insulation filler (hollow glass microbeads HL60), 13% heavy calcium powder, 1% polycarboxylate 5040-type wetting dispersant, and 1% DH3100 thickening agent.

[0042] The specific preparation process of thermal insulation coating 1 is as follows:

[0043] To prepare a radiation-type reflective thermal insulation coating, 1% polycarboxylate 5040-type dispersant, 10% deionized water, and 45% silicone-acrylic emulsion water-based film-forming material were sequentially added to a beaker and stirred thoroughly. Then 10% reflective thermal insulation filler (self-made flower-shaped rutile titanium dioxide), 5% radiation thermal insulation filler (iron trioxide, manganese dioxide, silicon carbide, chromium trioxide, and copper oxide, with a mass ratio of 2:2:2:1:1), 15% barrier-type thermal insulation filler (hollow glass microbeads HL60), and 13% heavy calcium powder were added and stirred again. Finally, 1% DH3100 thickening agent was added to complete the preparation.

[0044] Figure 1 The scanning electron microscope image of the flower-shaped rutile titanium dioxide prepared in Example 1 is shown in Figure 1. Figure 1It can be seen that a large number of petal-like protrusions are generated on the surface of the rutile titanium dioxide, and a large number of needle-like flocculent hairs are generated on the surface of the protrusions. The flower-like hierarchical structure greatly increases the surface area of the rutile titanium dioxide, and the reflection of sunlight is more sufficient, and the heat insulation performance is good. Figure 1 It can be seen that a flower-like hierarchical structure is generated on the surface of the rutile titanium dioxide, and the surface area of the rutile titanium dioxide is greatly increased.

[0045] Comparative Example 1

[0046] The difference from Example 1 is that the PH of the solution is adjusted from 8 to 5 in step (1). The flower-like rutile titanium dioxide prepared in this comparative example is used as a reflective heat insulation filler to prepare heat insulation coating 2.

[0047] Figure 2 The scanning electron microscope image of the flower-like rutile titanium dioxide prepared in Comparative Example 1 is shown in Figure 2. Figure 2 It can be seen that in an acidic environment, the surface of the rutile titanium dioxide has only a small amount of protrusions, and it is difficult to form flower-like rutile titanium dioxide with a large surface area, the solar reflectivity is small, and the heat insulation performance is small.

[0048] Comparative Example 2

[0049] The difference from Example 1 is that the PH of the solution is adjusted from 8 to 11 in step (1). The flower-like rutile titanium dioxide prepared in this comparative example is used as a reflective heat insulation filler to prepare heat insulation coating 3.

[0050] Comparative Example 3

[0051] The difference from Example 1 is that the PH adjusting agent 0.1 mol / L NaOH solution is replaced by ammonia water (NH3 content is 25% to 28%) in step (1). The flower-like rutile titanium dioxide prepared in this comparative example is used as a reflective heat insulation filler to prepare heat insulation coating 4.

[0052] Figure 3 The scanning electron microscope image of the flower-like rutile titanium dioxide prepared in Comparative Example 3 is shown in Figure 4. Figure 3 It can be seen that when the PH adjusting agent is ammonia water (NH3 content is 25% to 28%), a flower-like hierarchical structure and larger particles are generated on the surface of the rutile titanium dioxide. This is because there is a large amount of water in the ammonia water, and the tetrabutyl titanate will rapidly hydrolyze to generate flocculent particulate matter (titanium hydroxide) when it comes into contact with water. The generation of flocculent particles will result in a decrease in the surface area of the flower-like rutile titanium dioxide, a decrease in solar reflectivity, and a decrease in heat insulation performance.

[0053] Comparative Example 4

[0054] The difference from Example 1 is that the temperature of the autoclave is constant at 120°C instead of 180°C in step (1). The flower-like rutile titanium dioxide prepared in this comparative example is used as a reflective heat-insulating filler to prepare heat-insulating paint 5.

[0055] Figure 4 The scanning electron microscope image of the flower-like rutile titanium dioxide prepared in Comparative Example 4 is shown in Figure 4. Figure 4 It can be seen that when the constant temperature of the autoclave is 120°C, the flower-like hierarchical structure is not formed on the surface of the rutile titanium dioxide. Too low a temperature will result in insufficient pressure, which is not conducive to the formation of flower-like rutile titanium dioxide.

[0056] Comparative Example 5

[0057] The difference from Example 1 is that the temperature of the autoclave is constant for 6 hours instead of 12 hours in step (1). The flower-like rutile titanium dioxide prepared in this comparative example is used as a reflective heat-insulating filler to prepare heat-insulating paint 6.

[0058] Comparative Example 6

[0059] The difference from Example 1 is that the proportion of metal oxides that can promote the formation of rutile titanium dioxide is increased in step (2) (the total mass of the added iron trioxide, tin dioxide, vanadium pentoxide and zinc oxide is increased from 0.5% to 2% of the mass fraction of the flower-like titanium dioxide). The flower-like rutile titanium dioxide prepared in this comparative example is used as a reflective heat-insulating filler to prepare heat-insulating paint 7.

[0060] Comparative Example 7

[0061] The difference from Example 1 is that no metal oxides that can promote the formation of rutile titanium dioxide are added in step (2) (the total mass of the added iron trioxide, tin dioxide, vanadium pentoxide and zinc oxide is 0.3% to 0.8% of the mass fraction of the flower-like titanium dioxide). The flower-like rutile titanium dioxide prepared in this comparative example is used as a reflective heat-insulating filler to prepare heat-insulating paint 8.

[0062] Comparative Example 8

[0063] The difference from Example 1 is that 10% of the reflective heat-insulating filler (flower-like rutile titanium dioxide prepared by the inventor) is replaced by 10% of the reflective heat-insulating filler (rutile titanium dioxide particles, 0.1 to 0.3 microns). The 10% rutile titanium dioxide particles (0.1 to 0.3 microns) prepared in this comparative example are used as a reflective heat-insulating filler to prepare heat-insulating paint 9.

[0064] Comparative Example 9

[0065] The difference from Example 1 is that 5% of the radiation heat insulation filler (ferric oxide, manganese dioxide, silicon carbide, chromium sesquioxide and copper oxide, the mass ratio of ferric oxide, manganese dioxide, silicon carbide, chromium sesquioxide and copper oxide is 2:2:2:1:1) is not added, 13% of the heavy calcium powder is changed to 18% of the heavy calcium powder, and the heat insulation coating prepared in Comparative Example 9 is recorded as heat insulation coating 10.

[0066] Comparative Example 10

[0067] The difference from Example 1 is that 5% of the radiation heat insulation filler is changed to 10% of the radiation heat insulation filler (ferric oxide, manganese dioxide, silicon carbide, chromium sesquioxide and copper oxide, the mass ratio of ferric oxide, manganese dioxide, silicon carbide, chromium sesquioxide and copper oxide is 2:2:2:1:1), 13% of the heavy calcium powder is changed to 8% of the heavy calcium powder, and the heat insulation coating prepared in Comparative Example 10 is recorded as heat insulation coating 11.

[0068] Comparative Example 11

[0069] The difference from Example 1 is that 10% of the reflection heat insulation filler (self-made flower-like rutile titanium dioxide) is changed to 15% of the reflection heat insulation filler (self-made flower-like rutile titanium dioxide), 13% of the heavy calcium powder is changed to 8% of the heavy calcium powder, and the heat insulation coating prepared in Comparative Example 11 is recorded as heat insulation coating 12.

[0070] Performance test

[0071] The heat insulation coatings prepared in Example 1 and Comparative Examples 1-11 are tested for performance, specifically: the above coatings are respectively coated on the same stainless steel plate using a coater to form a coating layer with a thickness of 800 microns, and the heat insulation performance and reflectivity are measured.

[0072] Solar reflectance ratio test: the reflectivity of the coating on the stainless steel plate is measured according to the standard of GJB2502-2015 using a C84-II reflectivity tester.

[0073] Hemispherical emittance test: the measurement is carried out at room temperature according to the standard of GJB2502-2015 using an IR-2 dual-band infrared emittance tester, and the coating is applied to a circular iron sheet with a diameter of 8 cm for measurement at room temperature.

[0074] Thermal conductivity test: the test is carried out according to the standard of GB / T10297-2015.

[0075] Heat insulation performance test: the coating is sprayed on the stainless steel plate using a coater, and the side with the coating is placed upwards in a heat insulation film temperature tester. The temperature probe below the glass plate collects the temperature before and after the infrared lamp irradiation, and the temperature difference is displayed.

[0076] Adhesion test: The standard is GB / T1720-79.

[0077] The test results are shown in Table 1 below:

[0078] Table 1 Performance test results of the radiation type reflective thermal insulation coating prepared in the examples

[0079] Sample Hemispherical emittance % Thermal insulation temperature difference (°C) Solar reflectance % Example 1 95.5 15.8 94.3 Comparative Example 1 95.5 10.8 85.8 Comparative Example 2 95.5 11.6 87.4 Comparative Example 3 95.5 12.2 88.2 Comparative Example 4 95.5 9.8 84.7 Comparative Example 5 95.5 12.5 89.2 Comparative Example 6 93.1 12.8 91.8 Comparative Example 7 95.5 12.6 89.3 Comparative Example 8 95.5 12.4 88.8 Comparative Example 9 82.1 9.1 92.7 Comparative Example 10 88.9 7.4 78.3 Comparative Example 11 89.8 11.2 91.1

[0080] From Figure 1 As can be seen from the performance test results in Table 1, the rutile titanium dioxide prepared in Example 1 generates a flower-like hierarchical structure on the surface, which greatly increases the surface area of the rutile titanium dioxide and makes the reflection of sunlight more sufficient, has the highest solar emission ratio and hemispherical emittance, and has the best thermal insulation performance.

[0081] In Comparative Example 1, the pH in step (1) is changed from 8 to 5, and the flower-like rutile titanium dioxide prepared has Figure 2 It can be seen that in an acidic environment, the surface of the rutile titanium dioxide has only a small amount of protrusions, and it is difficult to form a flower-like rutile titanium dioxide with a large surface area, and the solar emission ratio and thermal insulation performance are lower than those of Example 1. In Comparative Example 2, the pH in step (1) is changed from 8 to 11, and the flower-like rutile titanium dioxide is generated too quickly, and the solar emission ratio is lower than that of Example 1. In Comparative Example 3, the pH adjuster in step (1) is changed from 0.1 mol / L NaOH solution to ammonia water (NH3 content is 25% to 28%), and the flower-like rutile titanium dioxide prepared has Figure 3 It can be seen that the surface has a flower-like hierarchical structure and larger particles are generated, which is due to the large amount of water in the ammonia water, and the tetrabutyl titanate will rapidly hydrolyze to generate flocculent particulate matter (titanium hydroxide). The generation of flocculent particulate matter will reduce the surface area of the flower-like rutile titanium dioxide, and the solar emission ratio and thermal insulation performance of Comparative Example 3 are lower than those of Example 1. In Comparative Example 4, the constant temperature of the high-pressure reaction kettle in step (1) is changed from 180 degrees Celsius to 120 degrees Celsius, and the flower-like rutile titanium dioxide prepared has Figure 4It can be seen that when the constant temperature of the autoclave is 120 degrees Celsius, the surface of the rutile titanium dioxide fails to form a flower-like hierarchical structure, and the low temperature leads to insufficient pressure, which is not conducive to the formation of flower-like rutile titanium dioxide. The solar emission ratio and the heat insulation performance of Comparative Example 4 are lower than those of Example 1. In Comparative Example 5, the constant temperature of the autoclave in step (1) is changed from 12 hours to 6 hours, which is insufficient for the reaction, leading to insufficient reaction and low yield of flower-like rutile titanium dioxide, and the solar emission ratio is lower than that of Example 1. In Comparative Example 6, the proportion of metal oxides that can promote the formation of rutile titanium dioxide is increased in step (2) (the total mass of the added iron trioxide, tin dioxide, vanadium pentoxide and zinc oxide is increased from 0.5% to 2% of the mass fraction of the flower-like titanium dioxide), and the solar emission ratio is not significantly improved, and the hemispherical emissivity is slightly lower than that of Example 1. In Comparative Example 7, the proportion of metal oxides that can promote the formation of rutile titanium dioxide is not increased in step (2) (the total mass of the added iron trioxide, tin dioxide, vanadium pentoxide and zinc oxide is 0.5% of the mass fraction of the flower-like titanium dioxide), and the yield of rutile titanium dioxide with a higher solar reflectance is low, and the solar reflectance of Comparative Example 7 is lower than that of Example 1. In Comparative Example 8, 10% of the reflective heat insulation filler (self-made flower-like rutile titanium dioxide) is changed to 10% of the reflective heat insulation filler (rutile titanium dioxide particles, 0.1-0.3 microns), and the surface area of the rutile titanium dioxide particles is smaller than that of the flower-like rutile titanium dioxide, and the reflection of sunlight is insufficient, and the solar reflectance of Comparative Example 7 is lower than that of Example 1, and the heat insulation performance is poorer than that of Example 1. In Comparative Example 9, no radiation heat insulation filler is added compared to Example 1, and the hemispherical emissivity of Comparative Example 9 is much lower than that of Example 1, and the active heat dissipation capacity of the coating prepared in Comparative Example 9 is weak, and the heat insulation performance of Comparative Example 9 is poorer than that of Example 1. In Comparative Example 10, 5% of the radiation heat insulation filler is changed to 10% of the radiation heat insulation filler compared to Example 1, and the excessive radiation heat insulation filler has serious agglomeration problems, which reduces the radiation surface area and weakens the active heat dissipation capacity of the coating, and the hemispherical emissivity and the heat insulation performance of Comparative Example 10 are poorer than those of Example 1. In Comparative Example 11, 10% of the reflective heat insulation filler (self-made flower-like rutile titanium dioxide) is changed to 15% of the reflective heat insulation filler (self-made flower-like rutile titanium dioxide) compared to Example 1, and the excessive reflective heat insulation filler has serious agglomeration problems, which leads to an increase in the thermal conductivity of the coating and a decrease in the solar reflectance, and the heat insulation effect of Comparative Example 11 is poorer than that of Example 1.

[0082] It should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit it. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the present application, which should be covered in the scope of the present application.

Claims

1. A method for preparing a radiation-reflective heat-insulating coating, characterized in that: The process includes thoroughly mixing tetrabutyl titanate and ethanol, stirring, adding a pH adjuster, mixing thoroughly, adding the mixture to a high-pressure reactor, heating the high-pressure reactor to a constant temperature, then cooling to room temperature, centrifuging, washing, drying, and storing to obtain flower-shaped titanium dioxide as a reflective heat-insulating material. Dry and prepared flower-shaped titanium dioxide is mixed with metal oxides that can promote the formation of rutile titanium dioxide and stirred thoroughly. Then it is calcined to obtain flower-shaped rutile titanium dioxide, a reflective heat insulation material. After thoroughly mixing the dispersant, deionized water and water-based film-forming substance, add the reflective heat insulation material flower-shaped rutile titanium dioxide, radiation heat insulation filler, barrier heat insulation filler and heavy calcium carbonate powder, stir thoroughly again, and finally add the thickener to obtain a radiation-type reflective heat insulation coating. The composition, by mass percentage of each raw material, is as follows: the reflective heat-insulating material, flower-shaped rutile titanium dioxide, is 10%; the radiative heat-insulating filler is 3-6%; the aqueous film-forming substance is 35-45%; the barrier-type heat-insulating filler is 10-15%; the dispersant is 0.5-2%; the thickener is 0.5-2%; the deionized water is 5-15%; and the heavy calcium carbonate powder is 5-15%. The pH adjuster is a 0.1 mol / L NaOH solution, used to adjust the pH of the solution to 7-9; The metal oxide is a composition of ferric oxide, tin dioxide, vanadium pentoxide, and zinc oxide, and the total mass added is 0.3% to 0.8% of the mass fraction of the flower-shaped titanium dioxide. The radiant heat insulation filler is a composition of ferric oxide, manganese dioxide, silicon carbide, chromium trioxide and copper oxide, with a mass ratio of ferric oxide, manganese dioxide, silicon carbide, chromium trioxide and copper oxide of 2:2:2:1:1; the aqueous film-forming substance is silicone acrylic emulsion; and the dispersant is polycarboxylate.

2. The preparation method according to claim 1, characterized in that: The volume ratio of tetrabutyl titanate to ethanol is 1~3:70~100.

3. The preparation method according to claim 1, characterized in that: The high-pressure reactor is heated to a constant temperature of 160℃~200℃ for ≥12 hours.

4. The preparation method according to claim 1, characterized in that: The calcination process yields flower-shaped rutile titanium dioxide, a reflective and heat-insulating material, at a temperature of 800°C for 2 hours.

5. The preparation method according to claim 1, characterized in that: The aforementioned barrier-type heat insulation filler is hollow glass microspheres.

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