A titanium dioxide with high heat insulation property and its preparation method

Abstract

The present invention discloses a titanium dioxide with high heat insulation performance and a preparation method thereof. The titanium dioxide includes a titanium dioxide substrate located in the core and a coating layer located on the surface of the titanium dioxide substrate. The coating layer includes at least a germanium oxide coating layer and a magnesium aluminum silicate coating layer from the inside to the outside. In this application, germanium oxide coating is first adopted. Germanium oxide is a wide-bandgap material, which can effectively improve the heat insulation performance of titanium dioxide. Then, magnesium aluminum silicate is used for the second coating. Magnesium aluminum silicate has a low thermal conductivity, which can improve the heat insulation performance of titanium dioxide. Moreover, magnesium aluminum silicate has a large specific surface area and a high porosity, which can improve the hiding power of the coating. Therefore, the titanium dioxide provided in this application, when used in coatings, can not only improve the heat resistance of the coatings, but also ensure the weather resistance and hiding power.

Description

Technical Field

[0001] The present invention belongs to the technical field of titanium dioxide preparation, and specifically relates to a titanium dioxide with high heat preservation performance and a preparation method thereof. Background Art

[0002] Building heat insulation is an important aspect of saving energy, improving the living environment and service functions. The proportion of building energy consumption in the total energy consumption of mankind is generally 30-40%, and most of it is the energy consumption of heating and air conditioning. Therefore, building energy conservation is of great significance. The development of thermal insulation materials is very fast. Adopting good thermal insulation technologies and materials in industry and construction can often achieve twice the result with half the effort.

[0003] Traditional thermal insulation materials mainly improve the gas void ratio, reduce the thermal conductivity and conduction coefficient. For fibrous thermal insulation materials, in order to increase convective heat transfer and radiative heat transfer in the use environment, a relatively thick cladding layer is required; while for profile inorganic thermal insulation materials, assembly construction is required, which has defects such as many joints, poor aesthetics, poor waterproof performance, and short service life. Therefore, people have been seeking and researching a new type of material that can greatly improve the heat insulation and reflection performance of thermal insulation materials.

[0004] At the same time, a boom in new thermal insulation materials has quietly emerged in China. Among them, new thermal insulation coatings have attracted more and more attention and favor due to their good economic benefits, energy conservation and environmental protection, heat insulation effect and simple construction. Patent CN115260861 A discloses adding ceramic microspheres, fly ash, etc. to the coating formula to improve the heat preservation performance of the coating, but in actual use, defects such as poor weather resistance and low hiding power cannot be avoided, while titanium dioxide can improve weather resistance and hiding power.

[0005] Therefore, the present application has developed a titanium dioxide with high heat preservation performance, which can not only improve the heat resistance of the coating, but also ensure weather resistance and hiding power. Summary of the Invention

[0006] The purpose of the present invention is to provide a titanium dioxide with high heat preservation performance and a preparation method thereof to solve the deficiencies of the prior art.

[0007] The purpose of the present invention is achieved by the following technical solutions:

[0008] A titanium dioxide with high heat preservation performance includes a titanium dioxide substrate located in the core and a coating layer located on the surface of the titanium dioxide substrate. The coating layer at least includes a germanium oxide coating layer and a magnesium aluminum silicate coating layer from the inside to the outside.

[0009] Preferably, the germanium oxide coating layer is formed by the following steps: a germanic acid source is in a titanium dioxide-based material slurry with a pH of 9.5-9.8, and by gradually adjusting the pH to 8-8.5, germanium oxide precipitates on the surface of the titanium dioxide substrate.

[0010] Preferably, the amount of germanium oxide coating, calculated as germanium oxide, is 0.1-0.2% of the mass of the titanium dioxide substrate.

[0011] Preferably, the magnesium aluminosilicate coating layer is formed by reacting a silicic acid source and a magnesium source with the titanium dioxide substrate coated with germanium oxide under the condition of pH 9-10, and then reacting with an aluminum source under the condition of pH 8-9.

[0012] Preferably, the coating layer further includes an aluminum oxide coating layer located outside the magnesium aluminosilicate coating layer.

[0013] The preparation method of the high heat-insulating titanium dioxide as described above includes the following steps:

[0014] S1. Take the titanium dioxide base material slurry, add a germanic acid source, and perform germanium oxide coating;

[0015] S2. Then add a silicic acid source, a magnesium source and an aluminum source to perform magnesium aluminosilicate coating.

[0016] Preferably, in step S1, first adjust the pH of the titanium dioxide base material slurry to 9.5-9.8, then add the germanic acid source, and then adjust the pH of the slurry to 8-8.5, and homogenize to form a germanium oxide coating layer.

[0017] Preferably, the addition amount of the germanic acid source, calculated as germanium oxide, is 0.1-0.2% of the mass of the titanium dioxide substrate.

[0018] Preferably, in step S2, the silicic acid source, the magnesium source and the aluminum source are added in sequence. After adding the magnesium source, adjust the pH of the slurry to 9-10, then add the aluminum source. After adding the aluminum source, adjust the pH of the slurry to 8-9, and homogenize to form a magnesium aluminosilicate coating layer.

[0019] Preferably, for the silicic acid source, the addition amount, calculated as silicon oxide, is 2-4% of the mass of the titanium dioxide substrate; for the magnesium source, the addition amount, calculated as magnesium oxide, is 1.2-2.5% of the mass of the titanium dioxide substrate; for the aluminum source, the addition amount, calculated as aluminum oxide, is 1.5-2% of the mass of the titanium dioxide substrate.

[0020] Preferably, the preparation method of the high heat-insulating titanium dioxide as described above includes the following steps:

[0021] S1. Take the titanium dioxide base material slurry, adjust the slurry concentration to 250-350 g / L, the temperature to 60-70 °C, and adjust the pH to 9.5-9.8;

[0022] S2. Add a germanate source. The addition time of the germanate source is 10 - 15 min. Then adjust the pH of the slurry to 8 - 8.5, and the pH adjustment time is 20 - 40 min. Then homogenize for 5 - 15 min;

[0023] S3. Add a silicate source. The addition time of the silicate source is 5 - 10 min;

[0024] S4. Add a magnesium source. The addition time of the magnesium source is 30 - 60 min. Then homogenize for 10 - 20 min. Ensure that the pH of the slurry is within 9 - 10 during the whole reaction process;

[0025] S5. Add an aluminum source. The addition time of the aluminum source is 20 - 30 min. Then homogenize for 10 - 20 min. Ensure that the pH of the slurry is within 8 - 9 during the whole reaction process.

[0026] This application first uses germanium dioxide for coating. Germanium dioxide is a wide - bandgap material, which can effectively improve the heat - preservation property of titanium dioxide. Then, magnesium aluminum silicate is used for the second - layer coating. Magnesium aluminum silicate has a low thermal conductivity, which can improve the heat - preservation performance of titanium dioxide. Moreover, magnesium aluminum silicate has a large specific surface area and a high porosity, which can improve the hiding power of the coating. Therefore, the titanium dioxide provided by this application, when used in coatings, can not only improve the heat - resistance of the coating, but also ensure the weather resistance and hiding power. Detailed implementation mode

[0027] The present invention provides a titanium dioxide with high heat - preservation property, including a titanium dioxide substrate located in the core and a coating layer located on the surface of the titanium dioxide substrate. The coating layer at least includes a germanium oxide coating layer and a magnesium aluminum silicate coating layer from the inside to the outside.

[0028] This application first uses germanium oxide to coat on the surface of titanium dioxide. Germanium oxide is a wide - bandgap material with optical properties such as high infrared refractive index and low scattering rate, which can effectively improve the heat - preservation property of titanium dioxide. Then, magnesium aluminum silicate is used for the second - layer coating. Compared with the aluminum silicate coating layer and magnesium silicate coating layer (the coating layer is microporous), the coating layer of magnesium aluminum silicate is fibrous, has a low thermal conductivity, which can improve the heat - preservation performance of titanium dioxide. Moreover, magnesium aluminum silicate has a large specific surface area and a high porosity, which can improve the hiding power of the coating. At the same time, it has good dispersibility and rheology in the coating, and can significantly improve the formulation applicability of titanium dioxide in the coating system.

[0029] Therefore, the titanium dioxide provided by this application not only has high heat - preservation performance, but also has good hiding power, and can be widely used in heat - preservation coatings.

[0030] Preferably, the germanium oxide coating layer is formed by the following steps: a germanic acid source is added to a titanium dioxide-based material slurry with a pH of 9.5 to 9.8, and by gradually adjusting the pH to 8 to 8.5, germanium oxide precipitates on the surface of the titanium dioxide substrate. The process of germanium oxide precipitation is similar to that of the silica film layer. The germanic acid source can be sodium germanate, potassium germanate, etc.

[0031] Preferably, the amount of germanium oxide coating, calculated as germanium oxide, is 0.1 to 0.2% of the mass of the titanium dioxide substrate. Research has shown that germanium oxide has good heat preservation performance under the condition of trace coating.

[0032] Preferably, the magnesium aluminum silicate coating layer is formed by reacting a silicic acid source and a magnesium source with the titanium dioxide substrate coated with germanium oxide under the condition of pH 9 to 10, and then reacting with an aluminum source under the condition of pH 8 to 9.

[0033] Preferably, the coating layer further includes an aluminum oxide coating layer located outside the magnesium aluminum silicate coating layer, and more preferably a boehmite-type aluminum oxide coating layer, which is beneficial to improving the dispersibility of titanium dioxide.

[0034] This application also provides a method for preparing the high heat-preserving titanium dioxide as described above, including the following steps:

[0035] S1. Take a titanium dioxide-based material slurry, add a germanic acid source, and perform germanium oxide coating;

[0036] S2. Then add a silicic acid source, a magnesium source, and an aluminum source, and perform magnesium aluminum silicate coating.

[0037] Preferably, in step S1, first adjust the pH of the titanium dioxide-based material slurry to 9.5 to 9.8, and alkaline substances such as sodium hydroxide and potassium hydroxide can be used to adjust the pH. Then add the germanic acid source, and then adjust the pH of the slurry to 8 to 8.5, and acidic substances such as sulfuric acid and hydrochloric acid can be used to adjust the pH, and homogenize to form a germanium oxide coating layer.

[0038] Preferably, the addition amount of the germanic acid source, calculated as germanium oxide, is 0.1 to 0.2% of the mass of the titanium dioxide substrate. The germanic acid source is added in the form of a solution, and the solution concentration, calculated as germanium oxide, is 40 to 80 g / L.

[0039] Preferably, the silicon source, magnesium source, and aluminum source are added in sequence. After adding the magnesium source, the pH of the slurry is adjusted to 9-10, and then the aluminum source is added. After adding the aluminum source, the pH of the slurry is adjusted to 8-9. Under this pH condition, aluminum ions and magnesium ions precipitate synchronously and are homogenized to form a magnesium aluminum silicate coating layer. The silicon source can be sodium silicate, potassium silicate, etc., and is added in the form of a solution. The solution concentration is 80-120 g / L in terms of silicon dioxide. The magnesium source can be magnesium sulfate, magnesium chloride, etc., and is added in the form of a solution. The solution concentration is 80-120 g / L in terms of magnesium oxide. The aluminum source can be sodium metaaluminate, potassium metaaluminate, aluminum sulfate, etc., and is added in the form of a solution. The solution concentration is 80-150 g / L in terms of aluminum oxide.

[0040] Preferably, the addition amount of the silicon source, in terms of silicon oxide, is 2-4% of the mass of the titanium dioxide substrate; the addition amount of the magnesium source, in terms of magnesium oxide, is 1.2-2.5% of the mass of the titanium dioxide substrate; the addition amount of the aluminum source, in terms of aluminum oxide, is 1.5-2% of the mass of the titanium dioxide substrate.

[0041] The present application provides a preferred method for preparing high heat-insulating titanium dioxide, including the following steps:

[0042] S1. Take a titanium dioxide-based material slurry, adjust the slurry concentration to 250-350 g / L, the temperature to 60-70 °C, and adjust the pH to 9.5-9.8;

[0043] S2. Add sodium germanate, and the addition time of sodium germanate is 10-15 min. Then adjust the pH of the slurry to 8-8.5, and the pH adjustment time is 20-40 min. Then homogenize for 5-15 min;

[0044] S3. Add the silicon source, and the addition time of the silicon source is 5-10 min;

[0045] S4. Add the magnesium source, and the addition time of the magnesium source is 30-60 min. Then homogenize for 10-20 min, and ensure that the pH of the slurry is 9-10 during the whole reaction process;

[0046] S5. Add the aluminum source, and the addition time of the aluminum source is 20-30 min. Then homogenize for 10-20 min, and ensure that the pH of the slurry is 8-9 during the whole reaction process;

[0047] S6. Add a certain amount of basic aluminum salt such as sodium metaaluminate and acidic aluminum salt such as aluminum sulfate in parallel flow, maintain the parallel flow pH at 7.8-8.2, and the parallel flow time is 20-40 min. Then homogenize for 10-30 min to form a boehmite alumina coating layer; the total amount of aluminum salt added in parallel flow is 1.5-3% of the mass of the titanium dioxide substrate in the slurry;

[0048] S7. Adjust the pH of the slurry to 5.8-6.2; adjust the pH of the slurry to weakly acidic, which is beneficial for water washing;

[0049] S8. The above slurry is washed with water, flash-evaporated, and steam-powdered to obtain the finished titanium dioxide product.

[0050] For the processes not defined in the present invention, such as washing with water, flash evaporation, steam powdering, etc., conventional methods in the art are selected.

[0051] Example 1

[0052] The uncoated titanium dioxide is crushed, wet-milled, sand-milled, and diluted. The slurry concentration is 300 g / L. Stirring is started and the temperature is raised to 70 °C; the pH of the slurry is adjusted to 9.6 with NaOH; a 0.1% sodium germanate solution is added to the titanium dioxide slurry with stirring within 15 min; the pH is adjusted to 8.3 with H2SO4 within 20 min and homogenized for 10 min; a 3.5% Na2SiO3 solution is added to the titanium dioxide slurry with stirring within 10 min; a 2% magnesium sulfate solution is added to the slurry with stirring within 60 min and homogenized for 10 min; a 1.2% sodium aluminate solution and a 0.8% aluminum sulfate solution are intermittently added to the slurry with stirring within 30 min to ensure that the pH of the solution is about 8.5 and homogenized for 10 min; then a 1.8% sodium aluminate solution and a 1.2% aluminum sulfate solution are added in parallel flow while maintaining the parallel flow pH at 8.0 ± 0.2, and the parallel flow addition time is 20 min and homogenized for 20 min; the pH is adjusted to 6.0 with dilute H2SO4 for 30 min and homogenized for 120 min; the product is obtained by washing with water, flash evaporation, and steam powdering.

[0053] Example 2

[0054] The uncoated titanium dioxide is crushed, wet-milled, sand-milled, and diluted. The slurry concentration is 300 g / L. Stirring is started and the temperature is raised to 60 °C; the pH of the slurry is adjusted to 9.7 with NaOH; a 0.1% sodium germanate solution is added to the titanium dioxide slurry with stirring within 15 min; the pH is adjusted to 8.2 with H2SO4 within 20 min and homogenized for 10 min; a 2% Na2SiO3 solution is added to the titanium dioxide slurry with stirring within 8 min; a 1.2% magnesium sulfate solution is added to the slurry with stirring within 30 min and homogenized for 5 min; a 0.9% sodium aluminate solution and a 0.6% aluminum sulfate solution are intermittently added to the slurry with stirring within 30 min to ensure that the pH of the solution is about 8.2 and homogenized for 10 min; a 1.2% sodium aluminate solution and a 0.8% aluminum sulfate solution are added in parallel flow while maintaining the parallel flow pH at 8.0 ± 0.2, and the addition time is 20 min and homogenized for 20 min; the pH is adjusted to 5.8 with dilute H2SO4 for 30 min and homogenized for 120 min; the product is obtained by washing with water, flash evaporation, and steam powdering.

[0055] Example 3

[0056] After the uncoated titanium dioxide is crushed, wet-milled, sand-milled and diluted, the slurry concentration is 300 g / L. Start stirring and heat up to 60 °C; adjust the pH of the slurry to 9.8 with NaOH; add 0.2% sodium germanate solution to the titanium dioxide slurry while stirring within 15 min; adjust the pH to 8.5 with H2SO4 within 20 min and homogenize for 10 min; add 1.5% Na2SiO3 solution to the titanium dioxide slurry while stirring within 8 min; add 1% magnesium sulfate solution to the slurry while stirring within 30 min and homogenize for 5 min; intermittently add 1.2% sodium aluminate solution and 0.8% aluminum sulfate solution to the slurry while stirring within 30 min to ensure that the pH of the solution is about 8.8 and homogenize for 10 min; simultaneously add 1.0% sodium aluminate solution and 0.5% aluminum sulfate solution in co-current flow, maintain the co-current flow pH at 8.0 ± 0.2, the addition time is 20 min and homogenize for 20 min; adjust the pH = 6.0 with dilute H2SO4, adjust for 30 min and homogenize for 120 min; wash with water, flash evaporate and steam pulverize to obtain the product.

[0057] Comparative Example 1

[0058] After the uncoated titanium dioxide is crushed, wet-milled, sand-milled and diluted, the slurry concentration is 300 g / L. Start stirring and heat up to 60 °C; adjust the pH of the slurry to 9.8 with NaOH; add 1.5% Na2SiO3 solution to the titanium dioxide slurry while stirring within 8 min; add 1% magnesium sulfate solution to the slurry while stirring within 30 min and homogenize for 5 min; intermittently add 1.2% sodium aluminate solution and 0.8% aluminum sulfate solution to the slurry while stirring within 30 min to ensure that the pH of the solution is about 8.8 and homogenize for 10 min; simultaneously add 1.5% sodium aluminate solution and 1% aluminum sulfate solution in co-current flow, maintain the co-current flow pH at 8.0 ± 0.2, the addition time is 20 min and homogenize for 20 min; adjust the pH = 6.0 with dilute H2SO4, adjust for 30 min and homogenize for 120 min; wash with water, flash evaporate and steam pulverize to obtain the product.

[0059] Comparative Example 2

[0060] After the uncoated titanium dioxide is crushed, wet-milled, sand-milled and diluted, the slurry concentration is 300 g / L. Start stirring and heat up to 60 °C; adjust the pH of the slurry to 9.8 with NaOH; add a 0.2% sodium germanate solution to the titanium dioxide slurry while stirring within 15 min; adjust the pH to 8.5 with H2SO4 within 20 min and homogenize for 10 min; at the same time, add a 3% NaAlO2 solution and a 2% Al2SO4 solution in parallel flow, maintain the parallel flow pH at 8.0 ± 0.2, add for 60 min and homogenize for 20 min; adjust the pH = 6.0 with dilute H2SO4, adjust for 30 min and homogenize for 120 min; wash with water, flash evaporate and steam pulverize to obtain the product.

[0061] Comparative Example 3

[0062] Foreign standard sample S.

[0063] Prepare a paint sample with a thickness of 5 mm according to the general paint process and measure the thermal conductivity of the sample at room temperature with a thermal conductivity analyzer. The results are shown in Table 1 as follows:

[0064] Table 1

[0065] Sample Thermal conductivity W / (m·K) Example 1 0.462 Example 2 0.497 Example 3 0.458 Comparative Example 1 0.617 Comparative Example 2 0.662 Comparative Example 3 0.584

[0066] As can be seen from the above table, the invention is significantly superior to the comparative example in terms of thermal conductivity.

[0067] Test according to the general heat insulation performance test method, and the results are shown in Table 2 as follows:

[0068] Table 2

[0069] Sample Heat insulation temperature difference (℃) Example 1 7.0 Example 2 6.2 Example 3 7.3 Comparative Example 1 3.7 Comparative Example 2 2.4 Comparative Example 3 5.1

[0070] Prepare latex paint according to the common latex paint formula and evaluate its application performance. The results are shown in Table 3 as follows:

[0071] Table 3

[0072] Sample L a b Hiding power Example 1 96.61 -0.16 1.95 90.52 Example 2 96.66 -0.15 1.99 89.96 Example 3 96.64 -0.16 1.93 90.14 Comparative Example 1 96.59 -0.18 1.96 90.04 Comparative Example 2 96.61 -0.18 1.94 89.93 Comparative Example 3 96.63 -0.19 1.93 89.71

[0073] As can be seen from the above data, the invention has better thermal conductivity and heat insulation performance than the comparative example, and its application performance is not inferior to that of the comparative example.

[0074] Although the preferred embodiments of the present invention have been described, additional changes and modifications can be made to these embodiments by those skilled in the art once they learn the basic creative concept. Therefore, the appended claims are intended to be construed to include the preferred embodiments as well as all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art can make various changes and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A titanium dioxide with high heat insulation property, characterized in that, It includes a titanium dioxide base material located in the core and a coating layer located on the surface of the titanium dioxide base material. The coating layer includes at least a germanium oxide coating layer and a magnesium aluminum silicate coating layer from the inside to the outside; The germanium oxide coating layer is formed by the following steps: A germanic acid source is in a titanium dioxide-based material slurry with a pH of 9.5 - 9.8, and by gradually adjusting the pH to 8 - 8.5, germanium oxide precipitates on the surface of the titanium dioxide base material; The magnesium aluminum silicate coating layer is formed by reacting a silicic acid source and a magnesium source with the titanium dioxide base material coated with germanium oxide under the condition of pH 9 - 10, and then reacting with an aluminum source under the condition of pH 8 - 9.

2. The high heat-insulating titanium dioxide as claimed in claim 1, wherein The amount of germanium oxide coating, calculated as germanium oxide, is 0.1 - 0.2% of the mass of the titanium dioxide base material.

3. The high heat-insulating titanium dioxide as claimed in claim 1, wherein The coating layer further includes an aluminum oxide coating layer located outside the magnesium aluminum silicate coating layer.

4. The preparation method of the high heat-insulating titanium dioxide according to any one of claims 1 to 3, characterized in that, It includes the following steps: S1. Take a titanium dioxide-based material slurry, first adjust the pH of the titanium dioxide-based material slurry to 9.5 - 9.8, then add a germanic acid source, and then adjust the pH of the slurry to 8 - 8.5, and homogenize to form a germanium oxide coating layer; S2. Then add a silicic acid source and a magnesium source, adjust the pH of the slurry to 9 - 10, and then add an aluminum source and adjust the pH of the slurry to 8 - 9, and homogenize to form a magnesium aluminum silicate coating layer.

5. The preparation method of the high heat-insulating titanium dioxide as claimed in claim 4, wherein The amount of germanic acid source added, calculated as germanium oxide, is 0.1 - 0.2% of the mass of the titanium dioxide base material.

6. The preparation method of the high heat-insulating titanium dioxide as claimed in claim 4, wherein The silicic acid source, the magnesium source and the aluminum source in step S2 are added in sequence.

7. The preparation method of the high heat-insulating titanium dioxide as claimed in claim 6, wherein For the silicic acid source, the added amount, calculated as silicon dioxide, is 2 - 4% of the mass of the titanium dioxide base material; for the magnesium source, the added amount, calculated as magnesium oxide, is 1.2 - 2.5% of the mass of the titanium dioxide base material; for the aluminum source, the added amount, calculated as aluminum oxide, is 1.5 - 2% of the mass of the titanium dioxide base material.

8. The preparation method of the high heat-insulating titanium dioxide according to claim 4, characterized in that, It includes the following steps: S1. Take a titanium dioxide-based material slurry, adjust the slurry concentration to 250 - 350 g / L, the temperature to 60 - 70 °C, and adjust the pH to 9.5 - 9.8; S2. Add a germanic acid source, the addition time of the germanic acid source is 10 - 15 min, then adjust the pH of the slurry to 8 - 8.5, the pH adjustment time is 20 - 40 min, and then homogenize for 5 - 15 min; S3. Add a silicic acid source, the addition time of the silicic acid source is 5 - 10 min; S4. Add a magnesium source, the addition time of the magnesium source is 30 - 60 min, and then homogenize for 10 - 20 min. Ensure that the pH of the slurry is within 9 - 10 during the whole reaction process; S5. Add an aluminum source, the addition time of the aluminum source is 20 - 30 min, and then homogenize for 10 - 20 min. Ensure that the pH of the slurry is within 8 - 9 during the whole reaction process.