A method for manufacturing super-high weather resistance titanium dioxide

Abstract

This invention discloses a method for manufacturing ultra-high weather-resistant titanium dioxide, belonging to the field of inorganic material preparation technology. The method involves preparing a rutile titanium dioxide base material into a slurry of a specific concentration. By precisely controlling pH, temperature, feeding time, and aging time, a high-density, highly compact amorphous hydrated silicon dioxide layer is formed on the surface of the titanium dioxide particles. An aging time ≥180 minutes is a key critical condition for the formation of the compact layer. A zirconium and aluminum salt co-precipitation reaction forms a zirconium-aluminum composite outer layer, used to passivate lattice defects in the titanium dioxide. This invention utilizes a three-layer gradient inorganic coating structure: a compact silicon layer to block photoelectron migration; a hollow mesoporous silicon layer to enhance ultraviolet scattering and buffer thermal stress; and an outer zirconium layer. The porous nature of the hollow mesoporous structure buffers thermal expansion stress and provides abundant anchoring points for the outer layer, ensuring a strong bond between the coating layers and preventing peeling.

Description

Technical Field

[0001] This invention relates to the field of inorganic preparation technology, and in particular to a method for manufacturing ultra-high weather-resistant titanium dioxide. Background Technology

[0002] Titanium dioxide (TiO2) is widely used in coatings, plastics, inks, and papermaking due to its excellent whiteness, hiding power, and chemical stability. However, titanium dioxide itself has photocatalytic activity. Under ultraviolet light irradiation, it generates photogenerated electrons and holes, which in turn catalyze the degradation of organic media in contact with it (such as resins in coatings and polymers in plastics), leading to problems such as chalking, yellowing, and loss of gloss in the coating film, seriously affecting the service life of the material.

[0003] To improve the weather resistance of titanium dioxide, surface coating technology is commonly used in industry. This involves coating the surface of titanium dioxide particles with one or more layers of inorganic oxides (such as silicon dioxide, aluminum oxide, zirconium oxide, etc.) to form a physical barrier that isolates them from the erosion of ultraviolet rays and active oxygen.

[0004] In existing technologies, sulfuric acid process titanium dioxide often employs a silicon-aluminum coating process, but the coating layer lacks sufficient density and cannot provide long-term shielding against ultraviolet light. While chloride process titanium dioxide can undergo more refined coating, existing traditional silicon-aluminum coatings are mostly single-layer or double-layer structures with insufficient functional differentiation between layers. This makes it difficult to simultaneously meet the dual requirements of "blocking photoelectron migration" and "scattering ultraviolet light." Furthermore, in multi-layer coatings, interface defects are prone to occur between different coating layers, leading to interlayer delamination during thermal expansion and contraction, resulting in coating layer failure. Increasing the coating layer thickness to improve weather resistance often leads to titanium dioxide particle agglomeration and decreased dispersibility, affecting the performance of downstream applications. Summary of the Invention

[0005] The purpose of this invention is to solve the problems existing in the prior art and to propose a method for manufacturing ultra-high weather-resistant titanium dioxide.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for manufacturing ultra-high weather-resistant titanium dioxide includes the following steps: S1. Prepare a slurry with a concentration of 250-350 g / L from rutile titanium dioxide base material, wherein the average particle size of the base material is 200-350 nm; S2. Heat the slurry obtained in S1 to 85-95℃, adjust the pH to 9.5-10.5 with alkali solution, and add silicate solution and acid in a co-current manner under stirring, controlling the feeding time to be 60-120 minutes. The amount of silicate added is 1.5%-3.0% of the mass of titanium dioxide, calculated as SiO2. After the feeding is completed, age the slurry for 180-240 minutes at a pH of 9.5-10.5 and a temperature of 85-95℃, forming a layer on the surface of titanium dioxide particles with a thickness of 3-8 nm and a density ≥2.1 g / cm³. 3 A dense, amorphous, hydrated silicon oxide layer; S3. Add a template agent to the slurry obtained in S2. The amount of template agent added is 0.5%-1.5% of the mass of titanium dioxide. Adjust the pH to 8.0-9.0. Add a silicate solution and control the reaction conditions to form a silicon layer with a hollow mesoporous structure on the surface of the dense amorphous hydrated silica layer. The thickness of the hollow mesoporous silicon layer is 10-20 nm, the pore size distribution is 2-10 nm, and the porosity is 30%-50%. S4. Adjust the pH of the slurry obtained in S3 to 5.5-6.5, add zirconium salt and aluminum salt. The amount of zirconium salt added is 0.8%-1.5% of the mass of titanium dioxide based on ZrO2, and the amount of aluminum salt added is 0.5%-1.0% of the mass of titanium dioxide based on Al2O3. Control the feeding time to 30-60 minutes, and after the feeding is completed, mature for 60-120 minutes to form a zirconium-aluminum composite layer with a thickness of 2-5 nm. S5. Add an organosilicon coupling agent and a polymer modifier to the slurry obtained in S4, and stir at 60-80℃ for 90-150 minutes for modification treatment. The amount of the organosilicon coupling agent added is 0.3%-0.8% of the mass of titanium dioxide, and the amount of the polymer modifier added is 0.2%-0.5% of the mass of titanium dioxide. S6. Filter and wash the slurry obtained in S5 until the conductivity is ≤500μS / cm, dry it at 120-150℃, and pulverize it with an air jet mill to a particle size D90≤0.6μm to obtain ultra-high weather-resistant titanium dioxide.

[0007] As a preferred embodiment, when the aging time in S2 is less than 180 minutes, the density of the dense amorphous hydrated silicon oxide layer is less than 2.0 g / cm³. 3 It cannot form an effective ultraviolet light shield.

[0008] As a preferred embodiment, the template agent in S3 is selected from at least one of polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer, hexadecyltrimethylammonium bromide, or polyethylene glycol. The hollow mesoporous silicon layer is used to scatter ultraviolet light, buffer thermal stress, and provide anchoring points for the zirconium-aluminum composite layer in S4 to enhance interlayer bonding.

[0009] As a preferred embodiment, the zirconium salt in S4 is at least one of zirconium oxychloride, zirconium nitrate, or zirconium sulfate, and the aluminum salt is at least one of sodium aluminate, aluminum sulfate, or aluminum chloride. The zirconium-aluminum composite layer is used to form chemical bonds with the lattice defects of titanium dioxide to passivate the photoactive centers.

[0010] As a preferred embodiment, the organosilicon coupling agent in S5 is at least one of γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, or γ-methacryloyloxypropyltrimethoxysilane, and the polymer modifier is at least one of polyethylene glycol, polyester polyol, or polyacrylate.

[0011] As a preferred embodiment, the modification treatment in S5 forms an organic-inorganic hybrid layer on the surface of the zirconium-aluminum composite layer. The organic-inorganic hybrid layer imparts hydrophobicity and oleophilicity to the titanium dioxide particles, enabling them to be dispersed in both aqueous and oily systems.

[0012] As a preferred embodiment, the rutile titanium dioxide base material in S1 is a primary rutile titanium dioxide product produced by the chloride process, and its lattice defect density is controlled to ≤0.5% through high-temperature calcination pretreatment.

[0013] As a preferred embodiment, during the pulverization process in step S6, an organic dispersant comprising 0.1%-0.3% of the mass of titanium dioxide is added, wherein the organic dispersant is selected from at least one of trimethylolpropane, pentaerythritol, or stearic acid.

[0014] As a preferred embodiment, the dense amorphous hydrated silicon oxide layer, the hollow mesoporous silicon layer, the zirconium-aluminum composite layer, and the organic-inorganic hybrid layer together constitute a gradient functional coating structure, wherein: The dense amorphous hydrated silicon oxide layer serves as the bottom layer, used to block photoelectrons from migrating from the titanium dioxide lattice to the surface. The hollow mesoporous silicon layer serves as an intermediate layer, used to scatter incident ultraviolet light and buffer thermal expansion stress. The zirconium-aluminum composite layer serves as the outer layer, used to passivate the remaining photoactive sites on the surface. The organic-inorganic hybrid layer, as the outermost layer, is used to improve dispersibility and provide a hydrophobic barrier; The synergistic effect of each layer in the gradient functional coating structure prevents titanium dioxide from undergoing photocatalytic degradation under ultraviolet light irradiation.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention achieves a step-by-step improvement in weather resistance by constructing a dense silicon layer to block photoelectron migration, a hollow mesoporous silicon layer to improve ultraviolet scattering and buffer thermal stress, and an external zirconium layer, resulting in a coating film that is free from powdering, cracking, and peeling.

[0016] 2. This invention utilizes organic-inorganic hybrid modification to form an amphiphilic organic layer on the surface of the inorganic coating layer, enabling titanium dioxide particles to exhibit excellent dispersion performance in both aqueous and oil-based systems. The oil absorption is ≤18g / 100g, and the grinding fineness is ≤15μm, meeting the processing requirements of high-end coatings, inks, plastics, and other fields. By using a hollow mesoporous silicon layer as an intermediate buffer layer, the defect of interface peeling easily occurs in traditional multi-layer coatings is solved. The porous nature of the hollow mesoporous structure can buffer thermal expansion stress and simultaneously provide abundant anchoring points for the outer layer, ensuring a firm bond between the coating layers and preventing peeling. Attached Figure Description

[0017] Figure 1 This is a flowchart of a method for manufacturing ultra-high weather-resistant titanium dioxide according to the present invention. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0019] It should be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0020] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0021] Example, refer to Figure 1 A method for manufacturing ultra-high weather-resistant titanium dioxide includes the following steps: Step 1: Prepare a slurry with a concentration of 250-350 g / L and an average particle size of 200-350 nm from rutile titanium dioxide base material; Step 2: Heat the slurry obtained in Step 2 to 85-95℃, adjust the pH to 9.5-10.5 with alkaline solution, and add silicate solution and acid in a co-current manner under stirring, controlling the feeding time to 60-120 minutes. The amount of silicate added, calculated as SiO2, is 1.5%-3.0% of the mass of titanium dioxide. After the feeding is completed, age the slurry for 180-240 minutes at a pH of 9.5-10.5 and a temperature of 85-95℃, forming a layer on the surface of the titanium dioxide particles with a thickness of 3-8 nm and a density ≥2.1 g / cm³. 3 A dense, amorphous, hydrated silicon oxide layer; Step 3: Add a template agent to the slurry obtained in Step 2. The amount of template agent added is 0.5%-1.5% of the mass of titanium dioxide. Adjust the pH to 8.0-9.0. Add a silicate solution and control the reaction conditions to form a silicon layer with a hollow mesoporous structure on the surface of the dense amorphous hydrated silicon oxide layer. The thickness of the hollow mesoporous silicon layer is 10-20 nm, the pore size distribution is 2-10 nm, and the porosity is 30%-50%. Step 4: Adjust the pH of the slurry obtained in step 3 to 5.5-6.5, add zirconium salt and aluminum salt. The amount of zirconium salt added is 0.8%-1.5% of the mass of titanium dioxide, calculated as ZrO2, and the amount of aluminum salt added is 0.5%-1.0% of the mass of titanium dioxide, calculated as Al2O3. Control the feeding time to 30-60 minutes, and after the feeding is completed, mature for 60-120 minutes to form a zirconium-aluminum composite layer with a thickness of 2-5 nm. Step 5: Add organosilicon coupling agent and polymer modifier to the slurry obtained in step 4, and stir at 60-80℃ for 90-150 minutes for modification treatment. The amount of organosilicon coupling agent added is 0.3%-0.8% of the mass of titanium dioxide, and the amount of polymer modifier added is 0.2%-0.5% of the mass of titanium dioxide. Step 6: Filter and wash the slurry obtained in step 5 until the conductivity is ≤500μS / cm, dry it at 120-150℃, and pulverize it with an air jet mill until the particle size D90≤0.6μm to obtain ultra-high weather-resistant titanium dioxide.

[0022] In the technical solution of this invention, the aging time in step two has a critical value. Through extensive experiments, the inventors discovered that when the aging time is less than 180 minutes, the density of the dense amorphous hydrated silicon oxide layer is less than 2.0 g / cm³. 3 It cannot form an effective ultraviolet light shield, resulting in a significant decrease in subsequent weather resistance.

[0023] In the technical solution of this invention, the template agent in step three is preferably selected from at least one of polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer (P123), hexadecyltrimethylammonium bromide (CTAB), or polyethylene glycol (PEG). The hollow mesoporous silicon layer has unique structural functions: its mesoporous structure can scatter incident ultraviolet light, reducing the direct irradiation intensity of ultraviolet light on the titanium dioxide lattice; its porous structure can buffer thermal expansion stress, preventing interfacial delamination of the multilayer coating structure during temperature changes; its abundant hydroxyl groups and pores on the surface can serve as "anchor points" for the subsequent zirconium-aluminum composite layer, significantly enhancing interlayer bonding.

[0024] In the technical solution of this invention, the zirconium salt in step four is preferably at least one of zirconium oxychloride, zirconium nitrate, or zirconium sulfate, and the aluminum salt is preferably at least one of sodium aluminate, aluminum sulfate, or aluminum chloride. The mechanism of action of the zirconium-aluminum composite layer lies in: zirconium ions (Zr...) 4+ Aluminum ions (Al) can form chemical bonds (Ti-O-Zr) with unsaturated titanium ions at titanium dioxide lattice defects, thereby effectively passivating photoactive centers and preventing photogenerated electrons and holes from migrating to the surface; 3+ Then it fills the structural defects in the coating layer, forming a dense protective outer layer.

[0025] In the technical solution of the present invention, the organosilicon coupling agent in step five is preferably at least one of γ-glycidoxypropyltrimethoxysilane (KH-560), γ-aminopropyltriethoxysilane (KH-550) or γ-methacryloyloxypropyltrimethoxysilane (KH-570), and the polymer modifier is preferably at least one of polyethylene glycol (PEG), polyester polyol or polyacrylate.

[0026] The modification treatment forms an organic-inorganic hybrid layer on the surface of the zirconium-aluminum composite layer. This hybrid layer is chemically bonded to the inorganic layer through the silicon-oxygen bonds of the organosilicon coupling agent. At the same time, the organic functional groups of the organosilicon coupling agent undergo a cross-linking reaction with the polymer modifier to form a hydrophobic and oleophilic amphiphilic surface, which endows titanium dioxide particles with excellent dispersion performance in both aqueous and oily systems.

[0027] In a preferred embodiment of the present invention, the rutile titanium dioxide base material in step one is a primary rutile titanium dioxide product produced by the chloride process, and its lattice defect density is controlled to ≤0.5% by high-temperature calcination pretreatment to reduce photocatalytic activity from the source.

[0028] In a preferred embodiment of the present invention, during the pulverization process in step six, an organic dispersing agent of 0.1%-0.3% by mass of titanium dioxide may be added. The organic dispersing agent is selected from at least one of trimethylolpropane, pentaerythritol, or stearic acid to further optimize the dispersibility of the product.

[0029] The present invention constructs a gradient functional coating structure on the surface of titanium dioxide particles through the above technical solution, consisting of a dense amorphous hydrated silicon oxide layer, a hollow mesoporous silicon layer, a zirconium aluminum composite layer, and an organic-inorganic hybrid layer, from the inside out.

[0030] In this structure: a dense, amorphous, hydrated silicon dioxide layer serves as the bottom layer, characterized by high density and compactness, effectively blocking photoelectrons from migrating from the titanium dioxide lattice to the surface; a hollow, mesoporous silicon layer serves as the middle layer, scattering incident ultraviolet light through its mesoporous structure while simultaneously buffering thermal expansion stress and preventing interlayer delamination; a zirconium-aluminum composite layer serves as the outer layer, passivating remaining photoactive sites by forming chemical bonds with lattice defects; and an organic-inorganic hybrid layer serves as the outermost layer, improving dispersibility through organic functional groups and providing a hydrophobic barrier. The complementary and synergistic effects of the layers in this gradient functional coating structure prevent photocatalytic degradation of titanium dioxide under ultraviolet light irradiation, thus achieving ultra-high weather resistance. Specific Implementation Example 1: This embodiment provides a method for manufacturing ultra-high weather-resistant titanium dioxide, including the following steps: Step 1. Take the rutile titanium dioxide primary product produced by the chlorination process (average particle size 280nm, lattice defect density 0.3%), add water to prepare a slurry with a concentration of 300g / L; Step 2. Heat the slurry obtained in Step 1 to 90℃, adjust the pH to 10.0 with NaOH solution, and add sodium silicate solution (100g / L based on SiO2) and dilute sulfuric acid in a parallel stream under stirring. Control the feeding time to 90 minutes. The amount of sodium silicate added is 2.0% of the mass of titanium dioxide based on SiO2. After the feeding is completed, age the slurry for 210 minutes at pH 10.0 and temperature 90℃ to form a layer with a thickness of 5nm and a density of 2.2g / cm³ on the surface of the titanium dioxide particles. 3 A dense, amorphous, hydrated silicon oxide layer; Step 3. Add template agent P123 (polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer) to the slurry obtained in step 2. The amount added is 1.0% of the mass of titanium dioxide. Adjust the pH to 8.5, add sodium silicate solution (100g / L based on SiO2), and control the reaction conditions to form a silicon layer with a hollow mesoporous structure on the surface of the dense amorphous hydrated silica layer. The thickness of this layer is 15nm, the pore size distribution is 5-8nm, and the porosity is 40%. Step 4. Adjust the pH of the slurry obtained in Step 3 to 6.0, add zirconium oxychloride solution (50 g / L based on ZrO2) and sodium aluminate solution (50 g / L based on Al2O3). The amount of zirconium oxychloride added is 1.2% of the mass of titanium dioxide based on ZrO2, and the amount of sodium aluminate added is 0.6% of the mass of titanium dioxide based on Al2O3. Control the feeding time to 45 minutes, and after the feeding is completed, mature for 90 minutes to form a zirconium-aluminum composite layer with a thickness of 3 nm. Step 5. Add γ-glycidyl etheroxypropyltrimethoxysilane (KH-560) and polyethylene glycol (PEG-4000) to the slurry obtained in step 4, with the addition amounts being 0.5% and 0.3% of the mass of titanium dioxide, respectively, and stir at 70°C for 120 minutes for modification treatment; Step 6. Filter and wash the slurry obtained in step 5 until the conductivity is ≤500μS / cm, dry it at 120℃ for 24 hours, and then pulverize it with an air jet mill to a particle size D90≤0.6μm to obtain ultra-high weather-resistant titanium dioxide.

[0032] The performance of the titanium dioxide prepared in this embodiment was tested: Oil absorption: Measured according to GB / T 5211.15-2014, the result is 16.8g / 100g.

[0033] Dispersibility: The grinding fineness was determined according to HG / T 4769-2014 to be 12 μm.

[0034] Weather resistance test: According to GB / T 23987-2009, the QUV-B (313nm) accelerated aging test machine was used. The test conditions were: light temperature 60℃, condensation temperature 50℃, and the light / condensation cycle was 4 hours of light / 4 hours of condensation. After 1000 hours of testing, the 60° gloss retention rate was 92.3%, the color difference ΔE=0.42, and there was no chalking, cracking, or peeling on the coating surface. Example 2

[0035] The difference between this embodiment and Embodiment 1 is that the aging time in step two is adjusted to 180 minutes.

[0036] The other steps and parameters are the same as in Example 1.

[0037] Test results: Oil absorption 17.2g / 100g, grinding fineness 13μm. QUV-B 1000h test: gloss retention 90.1%, ΔE=0.48. Example 3

[0038] The difference between this embodiment and Embodiment 1 is that in step four, the amount of zirconium salt added is 0.8% of the mass of titanium dioxide, calculated as ZrO2.

[0039] The other steps and parameters are the same as in Example 1.

[0040] Test results: Oil absorption 16.5g / 100g, grinding fineness 11μm. QUV-B 1000h test: gloss retention 90.8%, ΔE=0.45.

[0041] Comparative Example 1 (Insufficient Aging Time) The difference between this comparative example and Example 1 is that the aging time in step two is adjusted to 120 minutes (lower than the critical value of 180 minutes defined in this invention).

[0042] The other steps and parameters are the same as in Example 1.

[0043] Test results: Oil absorption 18.5g / 100g, grinding fineness 15μm. QUV-B 1000h test: gloss retention 78.5%, ΔE=1.23. Slight chalking appeared on the coating surface.

[0044] The results showed that when the aging time of the dense silicon layer was less than 180 minutes, the silicon layer density was insufficient (measured at 1.9 g / cm³). 3 It cannot form an effective ultraviolet light shield, and its weather resistance is significantly reduced.

[0045] Comparative Example 2 (hollow mesoporous silicon layer omitted) The difference between this comparative example and Example 1 is that step three is omitted, that is, a hollow mesoporous silicon layer is not formed, and zirconium-aluminum composite coating is directly applied to the surface of the dense silicon layer.

[0046] The other steps and parameters are the same as in Example 1.

[0047] Test results: Oil absorption 17.8g / 100g, grinding fineness 14μm. QUV-B 1000h test: gloss retention 85.6%, ΔE=0.89.

[0048] The results show that the hollow mesoporous silicon layer plays an irreplaceable role in improving weather resistance, and its functions of scattering ultraviolet rays and buffering thermal stress cannot be completely replaced by other layers.

[0049] Comparative Example 3 (Zirconium-aluminum composite layer omitted) The difference between this comparative example and Example 1 is that step four is omitted, that is, the zirconium-aluminum composite layer is not formed, and organic modification is carried out directly after the hollow mesoporous silicon layer is formed.

[0050] The other steps and parameters are the same as in Example 1.

[0051] Test results: Oil absorption 16.2g / 100g, grinding fineness 10μm. QUV-B 1000h test: gloss retention 87.2%, ΔE=0.78.

[0052] The results show that the zirconium-aluminum composite layer plays a key role in passivating lattice defects and improving weather resistance.

[0053] Comparative Example 4 (Commercially Available Products) A commercially available brand of high weather-resistant titanium dioxide (model: R-960) was selected as comparative example 4.

[0054] Test results: Oil absorption 18.2g / 100g, grinding fineness 16μm. QUV-B 1000h test: gloss retention 82.4%, ΔE=1.15.

[0055] Comparative Example 5 (Insufficient aging time + omission of zirconium layer) The difference between this comparative example and Example 1 is that the aging time in step two is adjusted to 120 minutes, and step four, the zirconium-aluminum composite layer, is omitted.

[0056] The other steps and parameters are the same as in Example 1.

[0057] Test results: Oil absorption 19.2g / 100g, grinding fineness 18μm. QUV-B 1000h test: gloss retention 65.3%, ΔE=2.18. Obvious chalking and yellowing were observed on the coating surface.

[0058] The results show that there is a synergistic effect between the aging time of the dense silicon layer and the zirconium-aluminum composite layer. When both are missing or insufficient, the weather resistance drops sharply, and the drop exceeds the sum of the effects of each individual factor, which confirms the "synergistic effect" between the multilayer structures of the present invention.

[0059] The test results above show that: The titanium dioxide prepared in Examples 1-3 of this invention exhibited a gloss retention rate of ≥90% and a color difference ΔE≤0.5 after 1000 hours of accelerated aging with QUV-B, which is significantly better than the comparative product.

[0060] Comparative Example 1 shows that when the aging time of the dense silicon layer is less than 180 minutes, the weather resistance decreases significantly, proving the criticality of the aging time of 180 minutes.

[0061] Comparative Examples 2-3 show that omitting the hollow mesoporous silicon layer or the zirconium-aluminum composite layer both lead to a decrease in weather resistance, proving that each layer has an irreplaceable function.

[0062] Comparative Example 5 shows that when the aging time is insufficient and the zirconium layer is omitted, the weather resistance drops sharply (65.3%), and the decrease (27.0%) exceeds the sum of the decreases of Comparative Example 1 (13.8%) and Comparative Example 3 (5.1%) (18.9%), which fully demonstrates the synergistic effect between the multilayer structures of the present invention.

[0063] In summary, the manufacturing method of ultra-high weather-resistant titanium dioxide provided by this invention features mild and highly controllable process conditions, readily available raw materials, and suitability for large-scale industrial production. The resulting titanium dioxide product exhibits excellent weather resistance and dispersibility, and can be widely used in wind turbine blade coatings, photovoltaic backsheets, automotive original equipment paints, outdoor architectural coatings, high-end plastics, and other fields, demonstrating broad market prospects.

[0064] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for manufacturing ultra-high weather-resistant titanium dioxide, Includes, characterized in that, Includes the following steps: S1. Prepare a slurry with a concentration of 250-350 g / L from rutile titanium dioxide base material, wherein the average particle size of the base material is 200-350 nm; S2. Heat the slurry obtained in S1 to 85-95℃, adjust the pH to 9.5-10.5 with alkali solution, and add silicate solution and acid in a co-current manner under stirring, controlling the feeding time to be 60-120 minutes. The amount of silicate added is 1.5%-3.0% of the mass of titanium dioxide, calculated as SiO2. After the feeding is completed, age the slurry for 180-240 minutes at a pH of 9.5-10.5 and a temperature of 85-95℃, forming a layer on the surface of titanium dioxide particles with a thickness of 3-8 nm and a density ≥2.1 g / cm³. 3 A dense, amorphous, hydrated silicon oxide layer; S3. Add a template agent to the slurry obtained in S2. The amount of template agent added is 0.5%-1.5% of the mass of titanium dioxide. Adjust the pH to 8.0-9.

0. Add a silicate solution and control the reaction conditions to form a silicon layer with a hollow mesoporous structure on the surface of the dense amorphous hydrated silica layer. The thickness of the hollow mesoporous silicon layer is 10-20 nm, the pore size distribution is 2-10 nm, and the porosity is 30%-50%. S4. Adjust the pH of the slurry obtained in S3 to 5.5-6.5, add zirconium salt and aluminum salt. The amount of zirconium salt added is 0.8%-1.5% of the mass of titanium dioxide based on ZrO2, and the amount of aluminum salt added is 0.5%-1.0% of the mass of titanium dioxide based on Al2O3. Control the feeding time to 30-60 minutes, and after the feeding is completed, mature for 60-120 minutes to form a zirconium-aluminum composite layer with a thickness of 2-5 nm. S5. Add an organosilicon coupling agent and a polymer modifier to the slurry obtained in S4, and stir at 60-80℃ for 90-150 minutes for modification treatment. The amount of the organosilicon coupling agent added is 0.3%-0.8% of the mass of titanium dioxide, and the amount of the polymer modifier added is 0.2%-0.5% of the mass of titanium dioxide. S6. Filter and wash the slurry obtained in S5 until the conductivity is ≤500μS / cm, dry it at 120-150℃, and pulverize it with an air jet mill to a particle size D90≤0.6μm to obtain ultra-high weather-resistant titanium dioxide.

2. The method for manufacturing ultra-high weather-resistant titanium dioxide according to claim 1, characterized in that, When the aging time in S2 is less than 180 minutes, the density of the dense amorphous hydrated silicon oxide layer is less than 2.0 g / cm³. 3 It cannot form an effective ultraviolet light shield.

3. The method for manufacturing ultra-high weather-resistant titanium dioxide according to claim 1, characterized in that, The template agent in S3 is selected from at least one of polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer, hexadecyltrimethylammonium bromide, or polyethylene glycol. The hollow mesoporous silicon layer is used to scatter ultraviolet rays, buffer thermal stress, and provide anchoring points for the zirconium-aluminum composite layer in S4 to enhance interlayer bonding.

4. The method for manufacturing ultra-high weather-resistant titanium dioxide according to claim 1, characterized in that, The zirconium salt in S4 is at least one of zirconium oxychloride, zirconium nitrate, or zirconium sulfate, and the aluminum salt is at least one of sodium aluminate, aluminum sulfate, or aluminum chloride. The zirconium-aluminum composite layer is used to form chemical bonds with the lattice defects of titanium dioxide to passivate the photoactive centers.

5. The method for manufacturing ultra-high weather-resistant titanium dioxide according to claim 1, characterized in that, The organosilicon coupling agent in S5 is at least one of γ-glycidoxypropyltrimethoxysilane, γ-aminopropyltriethoxysilane, or γ-methacryloyloxypropyltrimethoxysilane, and the polymer modifier is at least one of polyethylene glycol, polyester polyol, or polyacrylate.

6. The method for manufacturing ultra-high weather-resistant titanium dioxide according to claim 1, characterized in that, The modification treatment in S5 forms an organic-inorganic hybrid layer on the surface of the zirconium-aluminum composite layer. The organic-inorganic hybrid layer imparts hydrophobicity and oleophilicity to the titanium dioxide particles, enabling them to be dispersed in both aqueous and oily systems.

7. The method for manufacturing ultra-high weather-resistant titanium dioxide according to claim 1, characterized in that, The rutile titanium dioxide base material in S1 is a primary rutile titanium dioxide product produced by the chloride process, and its lattice defect density is controlled to ≤0.5% through high-temperature calcination pretreatment.

8. The method for manufacturing ultra-high weather-resistant titanium dioxide according to claim 1, characterized in that, In the S6 pulverization process, an organic dispersant is added at a mass of 0.1%-0.3% of titanium dioxide. The organic dispersant is selected from at least one of trimethylolpropane, pentaerythritol, or stearic acid.

9. The method for manufacturing ultra-high weather-resistant titanium dioxide according to claim 1, characterized in that, The dense amorphous hydrated silicon oxide layer, the hollow mesoporous silicon layer, the zirconium-aluminum composite layer, and the organic-inorganic hybrid layer together constitute a gradient functional coating structure, wherein: The dense amorphous hydrated silicon oxide layer serves as the bottom layer, used to block photoelectrons from migrating from the titanium dioxide lattice to the surface. The hollow mesoporous silicon layer serves as an intermediate layer, used to scatter incident ultraviolet light and buffer thermal expansion stress. The zirconium-aluminum composite layer serves as the outer layer, used to passivate the remaining photoactive sites on the surface. The organic-inorganic hybrid layer, as the outermost layer, is used to improve dispersibility and provide a hydrophobic barrier; The synergistic effect of each layer in the gradient functional coating structure prevents titanium dioxide from undergoing photocatalytic degradation under ultraviolet light irradiation.

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