Thermal insulation coating capable of resisting temperature of 600 DEG C and containing In2O3 and rutile type TiO2 aerogel and preparation method of thermal insulation coating

Abstract

The invention belongs to the technical field of coatings, and discloses a 600 DEG C heat insulation coating containing In2O3 and rutile type TiO2 aerogel and a preparation method of the 600 DEG C heat insulation coating. The coating is composed of an organic-inorganic compound adhesive, In2O3 at rutile type TiO2 aerogel, hollow glass beads, HAP ultra-long nanowires and auxiliaries, the aerogel is prepared by combining sol-gel with CO2 supercritical drying, and the aerogel is calcined at 800 DEG C to form a rutile crystal form. The compound adhesive is prepared from alkaline silica sol, modified organic silicon emulsion and a silane coupling agent through hydro-thermal synthesis. The coating is prepared by dispersing all the components at a high speed, heat conduction is inhibited by using aerogel nanopores, infrared radiation is reflected synergistically by rutile TiO2 and In2O3, and heat convection is blocked by a lock catch structure formed by hollow glass beads and HAP nanowires. The thermal conductivity of the obtained coating at 600 DEG C is as low as 0.035-0.044 W / (m.K), the coating has excellent temperature resistance, thermal shock resistance and full-wave band heat reflection capacity, and the technical problems of high-temperature phase change, structural collapse and poor thermal stability of a traditional coating are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of coatings, and in particular relates to a 600°C heat-insulating coating containing In2O3@rutile TiO2 aerogel and a preparation method thereof. Background Art

[0002] In recent years, global warming has become increasingly evident, with significant impacts from high energy consumption and heat radiation. Energy pollution in the construction and industrial sectors is particularly significant, leading to an increasing use of green and environmentally friendly materials. As an innovative, environmentally friendly material, reflective thermal insulation coatings are gaining a significant foothold in these sectors. Their superior thermal insulation and energy-saving properties are injecting new vitality into the development of green environmental protection.

[0003] Traditional reflective thermal insulation coatings generally have the following problems:

[0004] (1) The reflectivity is limited (usually ≤80%), which cannot effectively block heat radiation;

[0005] (2) Insufficient high temperature resistance, prone to phase change or decomposition when exposed to an environment above 200°C for a long time;

[0006] (3) The coating thickness is inconsistent with the construction process. For example, barrier coatings need to be applied thickly to reduce heat conduction, but this can easily lead to cracking and poor adhesion.

[0007] (4) The material is not stable enough and is easily affected by ultraviolet rays, humidity and chemical corrosion, resulting in performance degradation. Summary of the Invention

[0008] The present invention aims to solve the key technical problems of traditional thermal insulation coatings at high temperatures of 600°C, such as low reflectivity, high thermal conductivity, coating cracking and poor thermal stability caused by material phase change and collapse of aerogel structure. Through the synergistic effect of In2O3@rutile TiO2 aerogel composite structure and organic-inorganic composite adhesive (silica sol / organic silicon interpenetrating network), the coating can achieve ultra-low thermal conductivity and stable heat reflective performance at 600°C.

[0009] The purpose of the present invention is achieved through the following technical solutions.

[0010] The preparation method of the thermal insulation coating containing In2O3@rutile TiO2 aerogel and resistant to 600°C temperature of the present invention is as follows:

[0011] A method for preparing a 600°C heat-insulating coating containing In2O3@rutile TiO2 aerogel, comprising: using In2O3@rutile TiO2 aerogel, an organic-inorganic composite adhesive, hollow glass microspheres, ultra-long hydroxyapatite (HAP) nanowires, a film-forming agent, a leveling agent, a quick-drying agent, a thickener, a wetting agent, and deionized water; and performing high-speed dispersing and stirring. The method is characterized in that:

[0012] (1) The organic-inorganic composite adhesive comprises alkaline silica sol, modified silicone emulsion, and silane coupling agent, which are calculated by mass fraction as follows: 60-80 parts of alkaline silica sol, 20-30 parts of modified silicone emulsion, and 2-5 parts of silane coupling agent. The silane coupling agent diluent, modified silicone emulsion, and alkaline silica sol are added to a hydrothermal reactor in proportion, and the reaction is continuously carried out at 120° C. and a pressure of 1 MPa for 6 hours to obtain an organic-inorganic composite adhesive.

[0013] Organic-inorganic composite adhesives affect the coating's anti-cracking performance and maximum heat resistance. According to product requirements, the coating dries naturally without cracking and has a maximum temperature resistance of ≥600°C.

[0014] (2) The In2O3@rutile TiO2 aerogel of the present invention is prepared by the following method:

[0015] S1: Tetrabutyl titanate (TBOT) was added dropwise into anhydrous ethanol (EtOH) and stirred thoroughly at room temperature to obtain a light yellow mixed solution, which was recorded as mixed solution 1;

[0016] S2: Add nano-In2O3 powder, H2O, EtOH, acetic acid (HAc) and N,N-dimethylformamide (DMF) to another beaker and stir vigorously at room temperature to obtain an off-white mixed solution, which is recorded as mixed solution 2;

[0017] S3: Use a dropper to draw mixed solution 2 and add it dropwise to mixed solution 1 at a rate of 1-2 mL / min, and stir to fully hydrolyze it to obtain a uniform In2O3@TiO2 sol;

[0018] S4: The In2O3@TiO2 sol was allowed to stand at room temperature for 2 hours to gel and obtain In2O3@TiO2 gel. The In2O3@TiO2 sol was then immersed in EtOH. The EtOH liquid level should be about 2 cm higher than the upper surface of the In2O3@TiO2 gel. The EtOH was replaced every 24 hours. This step was repeated 3 to 4 times to fully displace the residual water and organic matter in the gel, obtaining In2O3@TiO2 wet gel.

[0019] S5: The In2O3@TiO2 wet gel is placed in a drying kettle of a multi-purpose supercritical test device, and an appropriate amount of anhydrous ethanol is added to completely submerge it, and CO2 supercritical drying is performed to obtain the In2O3@TiO2 aerogel.

[0020] S6: placing the In2O3@TiO2 aerogel in a tubular furnace, setting the heating rate of the tubular furnace to 1°C / min, the calcination temperature to 800°C, and the calcination time to 3 hours. After the tubular furnace temperature is naturally cooled to room temperature, the sample is taken out. The high-temperature calcination treatment changes the crystal phase of the TiO2 material to obtain In2O3@rutile TiO2 aerogel;

[0021] (3) Calculated by mass fraction: 100 parts of organic-inorganic composite adhesive, 20-40 parts of In2O3@rutile TiO2 aerogel, 40-65 parts of hollow glass microspheres, 12-15 parts of HAP ultra-long nanowires, 2-4 parts of film-forming agent, 0.5-1.5 parts of leveling agent, 1.5-3 parts of quick-drying agent, 0.5-1.5 parts of thickener, and 0.5-1.5 parts of wetting agent. Add the above components in sequence and stir at high speed for 30-60 minutes. Add deionized water to adjust the viscosity of the coating according to the requirements of scraping to obtain a gray-white viscous In2O3@rutile TiO2 aerogel heat-insulating coating resistant to 600℃.

[0022] The mixed solution 1 of the present invention comprises, by mass fraction, 10 to 20 parts of TBOT and 20 to 30 parts of EtOH.

[0023] The mixed solution 2 of the present invention comprises, by mass fraction, 2 to 5 parts of nano-In2O3 powder, 2 to 4 parts of H2O, 10 to 20 parts of EtOH, 2 to 5 parts of HAc, and 0.5 to 1.5 parts of DMF.

[0024] The CO2 supercritical drying pressure of the present invention is 10-13 MPa, the drying temperature is 40-55° C., and the drying time is 30-60 min.

[0025] Compared with the existing preparation method of thermal insulation coating, the present invention has the following advantages and beneficial effects:

[0026] (1) The present invention adds TiO2 aerogel and dopes nano-In2O3 powder, combines the optical performance advantages of TiO2 and In2O3 powder, and can reflect back infrared wavelengths with obvious thermal effects; it has the high porosity and temperature resistance of nano-powder and aerogel, and the nano-pores are smaller than the free path of air molecules, achieving high-performance temperature resistance and heat insulation.

[0027] (2) The present invention uses a composite organic-inorganic adhesive rather than a simple mixture. The silane coupling agent is fully hydrolyzed, and the hydrolysis product is silanol, which plays a role in coupling and anchoring the alkaline silica sol and the modified silicone emulsion, thereby enhancing the bonding strength, adhesion and temperature resistance of the adhesive.

[0028] (3) The thermal insulation coating is prepared by using In2O3@rutile TiO2 aerogel, which is suitable for large-scale production, has simple construction conditions and excellent thermal insulation performance.

[0029] (4) Synergistic effect of hollow glass microspheres and HAP nanowires

[0030] Hollow glass microspheres (40-65 parts) block heat convection by closing pores, but the gaps between them easily form heat conduction channels. HAP ultra-long nanowires (12-15 parts) with high aspect ratio (>100) are interspersed between microspheres to form a "micro-nano interlocking structure", which not only enhances the mechanical strength of the coating but also scatters heat radiation through multi-level channels. In addition, the nanorod-like structure of HAP ( <002> The preferential growth in crystal direction can directionally reflect infrared waves, forming a complementary reflection spectrum with In2O3@TiO2 aerogel to achieve full-band thermal insulation.

[0031] (5) Synergistic effect of organic-inorganic composite adhesives

[0032] A single adhesive system struggles to achieve both heat resistance and adhesion. Alkaline silica sol (60-80 parts) provides a heat-resistant backbone through a rigid Si-O-Si network, while a modified silicone emulsion (20-30 parts) imparts flexibility and substrate adhesion to the coating. A silane coupling agent (2-5 parts) bridges the inorganic / organic interface through hydrogen and chemical bonds, inhibiting phase separation at high temperatures. A hydrothermal reaction (120°C, 1 MPa, 6 hours) promotes the formation of an interpenetrating network between the silica sol and emulsion, improving the coating's density and thermal shock resistance.

[0033] (6) 800℃ calcination induced crystal phase transformation

[0034] Calcination treatment (heating to 800℃ at 1℃ / min and maintaining for 3h) promotes the complete conversion of anatase TiO2 into rutile (conversion temperature ≥610℃). At the same time, In2O3 nanoparticles form strong chemical bonds (Ti-O-In) with TiO2 through surface hydroxyl groups, thereby improving the temperature resistance limit of the composite material to above 600℃.

[0035] (7) Titanium dioxide has the characteristics of high refractive index and strong hiding power, so it can be used in heat-reflective coatings without the need for adding covering pigments. Titanium dioxide has three crystal forms: rutile, anatase, and brookite. Anatase is a metastable phase. The temperature at which pure anatase titanium dioxide is converted to rutile titanium dioxide is 610-915°C, which completely converts anatase titanium dioxide into rutile titanium dioxide.

[0036] Rutile titanium dioxide is chemically stable, non-toxic, and has excellent heat resistance, providing effective UV shielding across the entire UV range. Aerogel is a highly porous, low-density material composed of nanoscale particles. Its complex three-dimensional network structure and nanoscale pore size significantly inhibit solid-state and gaseous heat conduction, resulting in extremely low thermal conductivity. In2O3@rutile TiO2 aerogel effectively reflects infrared waves, effectively suppressing the radiative propagation of heat, further enhancing thermal insulation performance.

[0037] Therefore, combining the ultra-low thermal conductivity and strong thermal stability of In2O3@rutile TiO2 aerogel, adding a large amount of In2O3@rutile TiO2 aerogel to high-temperature resistant coatings can greatly improve the coating's thermal insulation, light-shielding, and temperature resistance properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is the SEM image of In2O3@rutile TiO2 aerogel;

[0039] Figure 2 It is a heat-insulating coating block containing In2O3@rutile TiO2 aerogel and is resistant to 600℃ temperature;

[0040] Figure 3 This is the XRD pattern of In2O3@rutile TiO2 aerogel after high-temperature calcination;

[0041] Figure 4 is the thermal conductivity of Example 1;

[0042] Figure 5 is the thermal conductivity of Example 2;

[0043] Figure 6 is the thermal conductivity of Example 3;

[0044] Figure 7 is the proportional thermal conductivity;

[0045] Figure 8 It is a 600℃ temperature resistance test of the coating block;

[0046] Figure 9 This is a comparative table of embodiments. DETAILED DESCRIPTION

[0047] The present invention is further described below in conjunction with experimental schemes, research results and examples, but the scope of protection claimed in the present invention is not limited thereto.

[0048] The purpose of the present invention is to provide a method for preparing a 600°C heat-insulating coating containing In2O3@rutile TiO2 aerogel. In2O3@rutile TiO2 aerogel is applied to the heat-insulating coating to prepare a heat-insulating coating containing In2O3@rutile TiO2 aerogel. The heat-insulating coating has good heat resistance and heat insulation properties, solves the problem of poor heat resistance and heat insulation properties of the coating, has low production cost, and is a high-quality heat-resistant heat-insulating coating.

[0049] Example 1

[0050] This embodiment provides a method for preparing a 600°C heat-insulating coating containing In2O3@rutile TiO2 aerogel, which comprises using In2O3@rutile TiO2 aerogel, an organic-inorganic composite adhesive, hollow glass microspheres, ultra-long hydroxyapatite (HAP) nanowires, a film-forming agent, a leveling agent, a quick-drying agent, a thickener, a wetting agent, and deionized water, and performing high-speed dispersion and stirring. The method comprises the following steps:

[0051] (1) The organic-inorganic composite adhesive comprises alkaline silica sol, modified silicone emulsion, and silane coupling agent, which are calculated by mass fraction as follows: 68 parts of alkaline silica sol, 30 parts of modified silicone emulsion, and 2 parts of silane coupling agent. The silane coupling agent diluent, modified silicone emulsion, and alkaline silica sol are added to a hydrothermal reactor in proportion, and the reaction is continuously carried out at 120° C. and a pressure of 1 MPa for 6 hours to obtain an organic-inorganic composite adhesive.

[0052] (2) The In2O3@rutile TiO2 aerogel is prepared by the following method:

[0053] S1: 10 parts of tetrabutyl titanate (TBOT) were added dropwise to 20 parts of anhydrous ethanol (EtOH), and the mixture was stirred thoroughly at room temperature to obtain a light yellow mixed solution, which was recorded as mixed solution 1;

[0054] S2: Add 2 parts of nano-In2O3 powder, 2 parts of H2O, 10 parts of EtOH, 2 parts of acetic acid (HAc), and 0.5 parts of N,N-dimethylformamide (DMF) to another beaker and stir vigorously at room temperature to obtain an off-white mixed solution, which is recorded as mixed solution 2.

[0055] S3: Use a dropper to draw mixed solution 2 and add it dropwise to mixed solution 1 at a rate of 1-2 mL / min, and stir to fully hydrolyze it to obtain a uniform and transparent In2O3@TiO2 sol;

[0056] S4: The In2O3@TiO2 sol was allowed to stand at room temperature for 2 hours to gel and obtain In2O3@TiO2 gel. The In2O3@TiO2 sol was then immersed in EtOH. The EtOH liquid level should be about 2 cm higher than the upper surface of the In2O3@TiO2 gel. The EtOH was replaced every 24 hours. This step was repeated 3 to 4 times to fully displace the residual water and organic matter in the gel, obtaining In2O3@TiO2 wet gel.

[0057] S5: The In2O3@TiO2 wet gel was placed in a drying vessel of a multi-purpose supercritical test device, and an appropriate amount of anhydrous ethanol was added to completely submerge it. The In2O3@TiO2 aerogel was obtained by supercritical CO2 drying at a pressure of 10 MPa, a drying temperature of 40°C, and a drying time of 50 min.

[0058] S6: placing the In2O3@TiO2 aerogel in a tubular furnace, setting the heating rate of the tubular furnace to 1°C / min, the calcination temperature to 800°C, and the calcination time to 3 hours. After the tubular furnace temperature is naturally cooled to room temperature, the sample is taken out. The high-temperature calcination treatment changes the crystal phase of the TiO2 material to obtain In2O3@rutile TiO2 aerogel;

[0059] (3) Calculated by mass fraction: 100 parts of organic-inorganic composite adhesive, 20 parts of In2O3@rutile TiO2 aerogel, 61 parts of hollow glass microspheres, 13 parts of HAP ultra-long nanowires, 3 parts of film-forming agent, 0.5 parts of leveling agent, 1.5 parts of quick-drying agent, 0.5 parts of thickener, and 0.5 parts of wetting agent. Add the above components in sequence and stir at high speed for 30 to 60 minutes. Add deionized water to adjust the viscosity of the coating according to the requirements of scraping to obtain a grayish white viscous In2O3@rutile TiO2 aerogel heat-insulating coating that is resistant to 600℃.

[0060] The thermal conductivity (25°C) of the In2O3@rutile TiO2 aerogel thermal insulation coating, which is resistant to 600°C temperatures, is 0.044W / (m·K). It dries naturally at room temperature without cracks and has a maximum temperature resistance of 615°C.

[0061] Example 2

[0062] This embodiment provides a method for preparing a 600°C heat-insulating coating containing In2O3@rutile TiO2 aerogel, which comprises using In2O3@rutile TiO2 aerogel, an organic-inorganic composite adhesive, hollow glass microspheres, ultra-long hydroxyapatite (HAP) nanowires, a film-forming agent, a leveling agent, a quick-drying agent, a thickener, a wetting agent, and deionized water, and performing high-speed dispersion and stirring. The method comprises the following steps:

[0063] (1) The organic-inorganic composite adhesive comprises alkaline silica sol, modified silicone emulsion, and silane coupling agent, which are calculated by mass fraction as follows: 72 parts of alkaline silica sol, 25 parts of modified silicone emulsion, and 3 parts of silane coupling agent. The silane coupling agent diluent, modified silicone emulsion, and alkaline silica sol are added to a hydrothermal reactor in proportion, and the reaction is continuously carried out at 120° C. and a pressure of 1 MPa for 6 hours to obtain an organic-inorganic composite adhesive.

[0064] (2) The In2O3@rutile TiO2 aerogel is prepared by the following method:

[0065] S1: 15 parts of tetrabutyl titanate (TBOT) were added dropwise to 30 parts of anhydrous ethanol (EtOH), and the mixture was stirred at room temperature to obtain a light yellow mixed solution, which was recorded as mixed solution 1;

[0066] S2: Add 5 parts of nano-In2O3 powder, 3 parts of H2O, 12 parts of EtOH, 3 parts of acetic acid (HAc), and 1 part of N,N-dimethylformamide (DMF) to another beaker and stir vigorously at room temperature to obtain an off-white mixed solution, which is recorded as mixed solution 2.

[0067] S3: Use a dropper to draw mixed solution 2 and add it dropwise to mixed solution 1 at a rate of 1-2 mL / min, and stir to fully hydrolyze it to obtain a uniform and transparent In2O3@TiO2 sol;

[0068] S4: The In2O3@TiO2 sol was allowed to stand at room temperature for 2 hours to gel and obtain In2O3@TiO2 gel. The In2O3@TiO2 sol was then immersed in EtOH. The EtOH liquid level should be about 2 cm higher than the upper surface of the In2O3@TiO2 gel. The EtOH was replaced every 24 hours. This step was repeated 3 to 4 times to fully displace the residual water and organic matter in the gel, obtaining In2O3@TiO2 wet gel.

[0069] S5: The In2O3@TiO2 wet gel was placed in a drying vessel of a multi-purpose supercritical test device, and an appropriate amount of anhydrous ethanol was added to completely submerge it. The In2O3@TiO2 aerogel was obtained by supercritical CO2 drying at a pressure of 11 MPa, a drying temperature of 45°C, and a drying time of 45 min.

[0070] S6: placing the In2O3@TiO2 aerogel in a tubular furnace, setting the heating rate of the tubular furnace to 1°C / min, the calcination temperature to 800°C, and the calcination time to 3 hours. After the tubular furnace temperature is naturally cooled to room temperature, the sample is taken out. The high-temperature calcination treatment changes the crystal phase of the TiO2 material to obtain In2O3@rutile TiO2 aerogel;

[0071] (3) Calculated by mass fraction: 100 parts of organic-inorganic composite adhesive, 35 parts of In2O3@rutile TiO2 aerogel, 41.5 parts of hollow glass microspheres, 15 parts of HAP ultra-long nanowires, 4 parts of film-forming agent, 1.0 part of leveling agent, 1.5 parts of quick-drying agent, 1.0 part of thickener, and 1.0 part of wetting agent. Add the above components in sequence and stir at high speed for 30 to 60 minutes. Add deionized water to adjust the viscosity of the coating according to the requirements of scraping to obtain a grayish white viscous In2O3@rutile TiO2 aerogel heat-insulating coating resistant to 600℃.

[0072] The thermal conductivity (25°C) of the In2O3@rutile TiO2 aerogel thermal insulation coating, which is resistant to 600°C temperatures, is 0.035W / (m·K). It dries naturally at room temperature without cracks and has a maximum temperature resistance of 640°C.

[0073] Example 3

[0074] This embodiment provides a method for preparing a 600°C heat-insulating coating containing In2O3@rutile TiO2 aerogel, which comprises using In2O3@rutile TiO2 aerogel, an organic-inorganic composite adhesive, hollow glass microspheres, ultra-long hydroxyapatite (HAP) nanowires, a film-forming agent, a leveling agent, a quick-drying agent, a thickener, a wetting agent, and deionized water, and performing high-speed dispersion and stirring. The method comprises the following steps:

[0075] (1) The organic-inorganic composite adhesive comprises alkaline silica sol, modified silicone emulsion, and silane coupling agent, which are calculated by mass fraction as follows: 75 parts of alkaline silica sol, 20 parts of modified silicone emulsion, and 5 parts of silane coupling agent. The silane coupling agent diluent, modified silicone emulsion, and alkaline silica sol are added to a hydrothermal reactor in proportion, and the reaction is continuously carried out at 120° C. and a pressure of 1 MPa for 6 hours to obtain an organic-inorganic composite adhesive.

[0076] (2) The In2O3@rutile TiO2 aerogel is prepared by the following method:

[0077] S1: 18 parts of tetrabutyl titanate (TBOT) were added dropwise to 25 parts of anhydrous ethanol (EtOH), and the mixture was stirred at room temperature to obtain a light yellow mixed solution, which was recorded as mixed solution 1;

[0078] S2: 4 parts of nano-In2O3 powder, 3 parts of H2O, 15 parts of EtOH, 3 parts of acetic acid (HAc), and 1.5 parts of N,N-dimethylformamide (DMF) were added to another beaker and stirred vigorously at room temperature to obtain an off-white mixed solution, which was recorded as mixed solution 2.

[0079] s3: Use a dropper to draw mixed solution 2 and add it dropwise to mixed solution 1 at a rate of 1-2 mL / min, and stir to fully hydrolyze it to obtain a uniform and transparent In2O3@TiO2 sol;

[0080] S4: The In2O3@TiO2 sol was allowed to stand at room temperature for 2 hours to gel and obtain In2O3@TiO2 gel. The In2O3@TiO2 sol was then immersed in EtOH. The EtOH liquid level should be about 2 cm higher than the upper surface of the In2O3@TiO2 gel. The EtOH was replaced every 24 hours. This step was repeated 3 to 4 times to fully displace the residual water and organic matter in the gel, obtaining In2O3@TiO2 wet gel.

[0081] S5: The In2O3@TiO2 wet gel was placed in a drying vessel of a multi-purpose supercritical test device, and an appropriate amount of anhydrous ethanol was added to completely submerge it. The In2O3@TiO2 aerogel was obtained by supercritical CO2 drying at a pressure of 12 MPa, a drying temperature of 55°C, and a drying time of 35 min.

[0082] S6: placing the In2O3@TiO2 aerogel in a tubular furnace, setting the heating rate of the tubular furnace to 1°C / min, the calcination temperature to 800°C, and the calcination time to 3 hours. After the tubular furnace temperature is naturally cooled to room temperature, the sample is taken out. The high-temperature calcination treatment changes the crystal phase of the TiO2 material to obtain In2O3@rutile TiO2 aerogel;

[0083] (3) Calculated by mass fraction: 100 parts of organic-inorganic composite adhesive, 30 parts of In2O3@rutile TiO2 aerogel, 48.5 parts of hollow glass microspheres, 14 parts of HAP ultra-long nanowires, 3 parts of film-forming agent, 1.0 part of leveling agent, 1.5 parts of quick-drying agent, 1.5 parts of thickener, and 1.5 parts of wetting agent. Add the above components in sequence and stir at high speed for 30 to 60 minutes. Add deionized water to adjust the viscosity of the coating according to the requirements of scraping to obtain a grayish white viscous In2O3@rutile TiO2 aerogel heat-insulating coating that is resistant to 600℃.

[0084] The thermal conductivity (25°C) of the In2O3@rutile TiO2 aerogel thermal insulation coating, which is resistant to 600°C temperatures, is 0.038W / (m·K). It dries naturally at room temperature without cracks and has a maximum temperature resistance of 635°C.

[0085] Example 4

[0086] Compared with Example 1, the preparation process of the organic-inorganic composite adhesive and In2O3@rutile TiO2 aerogel is the same, except that the coating formula of Example 1 is replaced with the coating formula of Example 2.

[0087] The thermal conductivity (25°C) of the In2O3@rutile TiO2 aerogel thermal insulation coating, which is resistant to 600°C temperatures, is 0.038W / (m·K). It dries naturally at room temperature without cracks and has a maximum temperature resistance of 615°C.

[0088] Example 5

[0089] Compared with Example 3, the preparation process of the organic-inorganic composite adhesive and In2O3@rutile TiO2 aerogel is the same, except that the coating formula of Example 3 is replaced by the coating formula of Example 2.

[0090] The thermal conductivity (25°C) of the In2O3@rutile TiO2 aerogel thermal insulation coating, which is resistant to 600°C temperatures, is 0.037W / (m·K). It dries naturally at room temperature without cracks and has a maximum temperature resistance of 635°C.

[0091] Example 6

[0092] Compared with Example 3, the preparation process of the organic-inorganic composite adhesive and In2O3@rutile TiO2 aerogel is the same, except that the coating formula of Example 3 is replaced with the coating formula of Example 2, and the amount of the organic-inorganic composite adhesive in the coating formula is changed to 80 parts.

[0093] The In2O3@rutile TiO2 aerogel heat-insulating coating with a temperature resistance of 600°C produces cracks when dried naturally at room temperature, and the thermal conductivity (25°C) and maximum temperature resistance cannot be measured.

[0094] Comparative Example

[0095] This comparative example provides a method for preparing a 600°C heat-insulating coating, which comprises using an organic-inorganic composite adhesive, hollow glass microspheres, hydroxyapatite (HAP) ultra-long nanowires, a film-forming agent, a leveling agent, a quick-drying agent, a thickener, a wetting agent, and deionized water, and performing high-speed dispersion and stirring steps, comprising the following steps:

[0096] (1) The organic-inorganic composite adhesive is the same as that in Example 2;

[0097] (2) Calculated by mass fraction: 100 parts of organic-inorganic composite adhesive, 76.5 parts of hollow glass microspheres, 15 parts of hydroxyapatite (HAP) ultra-long nanowires, 4 parts of film-forming agent, 1.0 part of leveling agent, 1.5 parts of quick-drying agent, 1.0 part of thickener, and 1.0 part of wetting agent. Add the above components in sequence and stir at high speed for 30 to 60 minutes. Add deionized water to adjust the viscosity of the coating according to the requirements of scraping to obtain a grayish white viscous thermal insulation coating.

[0098] The thermal conductivity coefficient of the thermal insulation coating (25°C) is 0.056W / (m·K), it dries naturally at room temperature without cracks, and has a maximum temperature resistance of 640°C.

Claims

1. A thermal insulation coating containing In2O3@rutile TiO2 aerogel and resistant to 600℃, characterized in that: Calculated by mass fraction: 100 parts of organic-inorganic composite adhesive, 20-40 parts of In2O3@rutile TiO2 aerogel, 40-65 parts of hollow glass microspheres, 12-15 parts of HAP ultra-long nanowires, 2-4 parts of film-forming agent, 0.5-1.5 parts of leveling agent, 1.5-3 parts of quick-drying agent, 0.5-1.5 parts of thickener, and 0.5-1.5 parts of wetting agent.

2. The coating according to claim 1, characterized in that The organic-inorganic composite adhesive comprises, by mass fraction, 60-80 parts of alkaline silica sol, 20-30 parts of modified silicone emulsion, and 2-5 parts of silane coupling agent.

3. The coating according to claim 1, characterized in that The In2O3@rutile TiO2 aerogel comprises, by mass fraction, 2 to 5 parts of nano-In2O3 powder, 10 to 20 parts of TBOT, 2 to 4 parts of H2O, 30 to 50 parts of EtOH, 2 to 5 parts of HAc, and 0.5 to 1.5 parts of DMF.

4. A method for preparing a 600°C heat-insulating coating containing In2O3@rutile TiO2 aerogel, characterized in that: Calculated by mass fraction: 100 parts of organic-inorganic composite adhesive, 20-40 parts of In2O3@rutile TiO2 aerogel, 40-65 parts of hollow glass microspheres, 12-15 parts of HAP ultralong nanowires, 2-4 parts of film-forming agent, 0.5-1.5 parts of leveling agent, 1.5-3 parts of quick-drying agent, 0.5-1.5 parts of thickener, and 0.5-1.5 parts of wetting agent. Add the above components in sequence and stir at high speed for 30-60 minutes. Add deionized water to adjust the viscosity of the coating according to the requirements of scraping to obtain an off-white viscous In2O3@rutile TiO2 aerogel heat-resistant 600°C thermal insulation coating.

5. The preparation method according to claim 4, characterized in that The organic-inorganic composite adhesive comprises, by mass fraction, 60-80 parts of alkaline silica sol, 20-30 parts of modified silicone emulsion, and 2-5 parts of silane coupling agent. The silane coupling agent diluent, modified silicone emulsion, and alkaline silica sol are added to a hydrothermal reactor in proportion, and the mixture is reacted continuously at 120° C. and a pressure of 1 MPa for 6 hours to obtain the organic-inorganic composite adhesive.

6. The preparation method according to claim 4, characterized in that The In2O3@rutile TiO2 aerogel comprises, by mass fraction, 2 to 5 parts of nano-In2O3 powder, 10 to 20 parts of TBOT, 2 to 4 parts of H2O, 30 to 50 parts of EtOH, 2 to 5 parts of HAc, and 0.5 to 1.5 parts of DMF, and is prepared by the following method: S1: TBOT was added dropwise to EtOH and stirred thoroughly at room temperature to obtain a light yellow mixed solution, which was recorded as mixed solution 1; S2: Add nano-In2O3 powder, H2O, EtOH, acetic acid HAc and N,N-dimethylformamide DMF to another beaker and stir vigorously at room temperature to obtain an off-white mixed solution, which is recorded as mixed solution 2; S3: Use a dropper to draw mixed solution 2 and add it dropwise to mixed solution 1 at a rate of 1-2 mL / min, and stir to fully hydrolyze it to obtain a uniform In2O3@TiO2 sol; S4: The In2O3@TiO2 sol is allowed to stand at room temperature for 2 hours. The In2O3@TiO2 sol is gelled to obtain In2O3@TiO2 gel, which is then immersed in EtOH. The EtOH liquid level needs to be about 2 cm higher than the upper surface of the In2O3@TiO2 gel and is replaced every 24 hours. This step is repeated 3 to 4 times to fully replace the residual water and organic matter in the gel to obtain In2O3@TiO2 wet gel. S5: The In2O3@TiO2 wet gel is placed in a drying vessel of a multi-purpose supercritical test device, and an appropriate amount of anhydrous ethanol is added to completely submerge it, and then subjected to CO2 supercritical drying to obtain the In2O3@TiO2 aerogel; S6: Place the In2O3@TiO2 aerogel in a tubular furnace, set the heating rate of the tubular furnace to 1℃ / min, the calcination temperature to 800℃, and the calcination time to 3h. After the tubular furnace temperature naturally cools to room temperature, take out the sample. The high-temperature calcination treatment changes the crystal phase of the TiO2 material to obtain In2O3@rutile TiO2 aerogel.

7. The preparation method according to claim 6, characterized in that: The CO2 supercritical drying pressure is 10-13 MPa, the drying temperature is 40-55°C, and the drying time is 30-60 min.

8. The preparation method according to claim 6, characterized in that Its characteristics are: The mass fraction of EtOH in the mixed solution 1 is 20 to 30 parts.

9. The preparation method according to claim 6, characterized in that Its characteristics are: The mass fraction of EtOH in the mixed solution 2 is 10 to 20 parts.

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