High-covering inorganic-organic coated titanium dioxide as well as preparation method and application thereof

Abstract

The invention discloses high-covering inorganic-organic coated titanium dioxide as well as a preparation method and application thereof, and belongs to the field of titanium dioxide. Rutile type titanium dioxide is added into a dispersing agent and is matched with 0.6-0.8 mm zirconium beads (the filling rate is 65%-80%) for sanding, silicate ions in sodium silicate are adsorbed on the surface of rutile type titanium dioxide, titanium dioxide is difficult to agglomerate, the dispersion uniformity of rutile type titanium dioxide particles in slurry is improved, the particle size is controlled to be uniform, and the light scattering efficiency is optimized; the preparation method comprises the following steps: adding an acidic aluminum salt and an alkaline aluminum salt at a specific temperature in a parallel flow manner, carrying out inorganic coating, adding an organic matter, carrying out organic coating, and finally obtaining the titanium dioxide through gas powder, and the titanium dioxide has the advantages of high titanium dioxide whiteness, low oil absorption, excellent glossiness and excellent covering power.

Description

TECHNICAL FIELD

[0001] The application relates to the field of titanium white powder, in particular to high-hiding inorganic-organic coated titanium white powder and a preparation method and application thereof. BACKGROUND

[0002] With the development of market diversification and the intensification of product quality competition, high-hiding and high-gloss titanium white powder has become a high-end material in the ink field. In terms of visual presentation, high gloss can significantly improve the texture of ink. When applied to cosmetic boxes and luxury packaging, it can enhance the attractiveness of the product. When used for label and poster printing, it can make colors more vibrant and images clearer, and strengthen the visual impact. In terms of performance, high-gloss titanium white powder, with high refractive index and dispersibility, can ensure uniform ink printing and reduce graininess. Its excellent weather resistance and chemical stability can resist ultraviolet radiation and ensure that outdoor billboards and other printed matter do not fade over time. High-hiding titanium white powder not only effectively covers the base color of the substrate, ensuring the purity of the pattern color, but also reduces the amount of formula used, reducing ink consumption and achieving VOC emission reduction and cost control. High-hiding and high-gloss titanium white powder has become a core material to meet the needs of ink aesthetics, function, process and market competition, and is the key to the development of high-end printed matter and functional ink.

[0003] The preparation process of high-performance titanium white powder is often complex. For example, patent CN112538283A discloses a preparation method of high-weather-resistant and high-hiding titanium white powder, which comprises the following steps: a, crushing titanium dioxide primary product to form a slurry, adding sodium silicate, and adjusting the pH value to 9.0-11.0; b, heating the slurry to 80-100 DEG C, adding sodium silicate solution, and adding an acidic aluminum-containing compound solution in a flow manner to maintain the pH value of the slurry at 8.0-10.0, and aging; c, cooling the aged slurry to 40-50 DEG C, adding sodium silicate solution, and adding an acidic aluminum-containing compound in a flow manner to maintain the pH value of the slurry at 8.0-10.0, and aging; d, adjusting the pH value of the slurry to 4.0-6.5 with an acidic aluminum-containing compound, and aging; e, adjusting the pH value of the slurry to 7.0-8.0 with an alkaline aluminum-containing compound, and filtering, washing, drying, and crushing to obtain the product.

[0004] CN115584147A discloses a coating method of titanium dioxide powder special for ink, comprising: adding dispersing agent and rutile titanium dioxide into deionized water for beating and dispersing, then sand grinding and screening; adding the sand grinding and screening slurry into a coating device for dilution, stirring and heating; adding acid aluminum salt solution to adjust the pH value of the slurry to be acidic and aging; adding basic aluminum salt solution and acid aluminum salt solution in parallel and aging; adding basic aluminum salt solution to adjust the pH value of the slurry to be basic and aging; adding basic aluminum salt solution and acid aluminum salt solution in parallel and aging; adding acid aluminum salt solution to adjust the pH value of the slurry to be neutral and aging; filtering and washing the aged slurry; and adding silane coupling agent drop by drop after beating the filter cake, and drying and crushing to obtain titanium dioxide powder special for ink.

[0005] Due to the increasing requirements for the hiding power of titanium dioxide in the field of ink, the preparation process of existing titanium dioxide is more strict, and the comprehensive performance of titanium dioxide is also improved synchronously. Therefore, the existing preparation of titanium dioxide still has problems to be solved, such as poor dispersibility, low whiteness, low gloss, and low hiding power. SUMMARY

[0006] In view of the above problems, the present application provides a high-hiding inorganic-organic coated titanium dioxide and a preparation method and application thereof. The titanium dioxide is prepared by inorganic coating and organic coating after sand grinding and dispersing, under specific temperature and coating conditions, to obtain titanium dioxide with high hiding power.

[0007] The present application provides a high-hiding inorganic-organic coated titanium dioxide, which is obtained by organic coating after aging of basic aluminum and acid aluminum after sand grinding of rutile titanium dioxide; the particle size of the high-hiding inorganic-organic coated titanium dioxide is 0.30-0.35 μm, the oil phase whiteness is 95-97, the oil dispersibility is 6.75, the color removal power is 2060-2080, and the oil absorption is 17-18 g / L. The gloss at 20° of the high-hiding inorganic-organic coated titanium dioxide is 22-29, the gloss at 60° is 87-90, and the gloss at 85° is 97-102; the hiding power of the high-hiding inorganic-organic coated titanium dioxide is 75-77%.

[0008] The present application also provides a preparation method of the high-hiding inorganic-organic coated titanium dioxide, comprising the following steps: Step 1: dissolving rutile titanium dioxide and dispersing agent in deionized water by stirring to obtain a mixed solution, sand grinding the mixed solution in a sand mill, and then screening, diluting, and maintaining pH to obtain a premixed slurry; Step 2: under continuous stirring, adding basic aluminum salt solution and acid aluminum salt solution to the premixed slurry for primary aging, then adjusting the pH of the system with an acid solution and continuing to stir for secondary aging to obtain an aged slurry. Step 3, the ripening slurry is filtered and the solid product is washed with deionized water to obtain a filter cake, the filter cake is pulped, then an organic substance is added and stirred, and then dried, crushed and air-powdered to obtain the high-hiding inorganic-organic coated titanium dioxide pigment.

[0009] Further, the mass of the dispersant in step 1 is 0.1-0.6% of the mass of the rutile titanium dioxide.

[0010] Further, the mass-volume ratio of the rutile titanium dioxide to the desalted water in step 1 is (1:1.5)-(1:3), wherein the unit of mass is g and the unit of volume is ml.

[0011] Further, the dispersant in step 1 is sodium silicate.

[0012] Further, the stirring and dissolving speed in step 1 is 300-500 rpm, and the stirring and dissolving time is 10-50 min.

[0013] Further, the sand mill in step 1 is filled with zirconium beads, the particle size of the zirconium beads is 0.4-0.8 mm, and the filling rate of the zirconium beads is 50-80%.

[0014] Further, the speed of the sand mill in step 1 is 2000-2500 rpm, and the sand milling time is 15-75 min.

[0015] Further, the mesh size of the sieving in step 1 is 300-350 mesh.

[0016] Further, the dilution desalted water in step 1, the stirring speed during dilution is 300-500 rpm, and the concentration of the titanium dioxide after dilution is 280-320 g / L.

[0017] Further, the pH value in step 1 is maintained at 9-10.5.

[0018] Further, the method for maintaining the pH value is: when the solution pH is greater than 10.5, 100 g / L aluminum sulfate is added for adjustment, and when the solution pH is less than 9, 100 g / L sodium metaaluminate is added for adjustment.

[0019] Further, the basic aluminum salt solution and the acidic aluminum salt solution in step 2 are added in parallel flow.

[0020] Further, the stirring speed in step 2 is 300-500 rpm.

[0021] Further, the heating temperature in step 2 is 40-70℃.

[0022] Further, the mass of the basic aluminum salt in the basic aluminum salt solution in step 2 is 1-2% of the mass of titanium dioxide in the system at this time.

[0023] Further, the concentration of the basic aluminum salt solution in step 2 is 90-120 g / L.

[0024] Further, the basic aluminum salt in the basic aluminum salt solution in step 2 is one or both of sodium metaaluminate or potassium metaaluminate.

[0025] Further, the mass of the acid aluminum salt in the acid aluminum salt solution in step 2 is 0.8-1.8% of the mass of titanium dioxide in the system at this time.

[0026] Further, the concentration of the acid aluminum salt solution in step 2 is 90-120 g / L.

[0027] Further, the acid aluminum salt in the acid aluminum salt solution in step 2 is one or more of aluminum nitrate, aluminum sulfate and aluminum chloride.

[0028] Further, the pH value in the first ripening in step 2 is 9-10.

[0029] Further, the time of the first ripening in step 2 is 90-120 min.

[0030] Further, the acid solution in step 2 is one or more of 180-200 g / L of sulfuric acid, phosphoric acid and nitric acid solution.

[0031] Further, the acid solution adjusts the pH of the system to 6-7.5 in step 2.

[0032] Further, the time of the second ripening in step 2 is 120-180 min.

[0033] Further, the conductivity of the filtrate in step 3 is ≤100 us / cm.

[0034] Further, the speed of the beating in step 3 is 300-500 rpm, the desalination water is used for the beating, and the time of the beating is 60-100 min.

[0035] Further, the amount of the organic matter added in step 3 is 0.1-0.5% of the mass of the rutile titanium dioxide at this time.

[0036] Further, the organic matter in step 3 is one or both of trimethylolpropane or trimethylolethane.

[0037] Further, the stirring speed in step 3 is 300-500 rpm, and the stirring time is 60-90 min.

[0038] Further, the drying temperature in step 3 is 100-150 DEG C, and the drying time is 5-10 h.

[0039] Further, the gas flow pressure in step 3 is 0.1-0.8 MPa.

[0040] Further, the feeding rate in step 3 is 100-200 Hz.

[0041] An ink, raw materials of the ink comprising the high-hiding inorganic organic coated titanium dioxide.

[0042] The beneficial effects of the present application are: 1. In the present application, rutile titanium dioxide is added into sodium silicate as a dispersant for sand milling. Silicate ions in sodium silicate are adsorbed on the surface of rutile titanium dioxide, increasing the electric charge surface negative charge density of rutile titanium dioxide, forming a double electric layer, so that the rutile titanium dioxide particles are difficult to agglomerate due to electrostatic repulsion, improving the dispersion uniformity of the rutile titanium dioxide particles in the slurry, thus improving the dispersibility of the titanium dioxide. Subsequently, the rutile titanium dioxide and the dispersant are sand milled at a specific size of zirconium beads and a specific filling rate, so that the particle size of the titanium dioxide is uniform, the loss of light scattering efficiency caused by excessively large or small particle size is reduced, the hiding power and gloss are maximized, the concentration of the titanium dioxide in the slurry after sand milling is high, and in order to prevent affecting the subsequent coating effect, the slurry is first diluted to obtain a suitable premixed slurry. 2. The dispersed slurry is inorganic coated at a specific coating temperature in the present application. At a specific temperature and pH in the present application, the inorganic aluminum salt solution stably forms boehmite particles, which can uniformly deposit and form a continuous and dense coating layer when colliding with titanium dioxide particles. In the present application, the inorganic coating is carried out by adding the acid aluminum salt and the basic aluminum salt in a concurrent manner. The mass of the rutile titanium dioxide in the system is calculated by the specific weight ratio, and the acid aluminum salt and the basic aluminum salt are added. The maturation process of the inorganic coating only needs twice, wherein the pH of the first maturation is 9-10.5, and the pH of the second maturation is 6-7.5. Under the change of pH from alkaline to acidic, the aluminum salt stably and uniformly coats the rutile titanium dioxide. Thereafter, the rutile titanium dioxide is organically coated by continuously adding an organic substance. After drying, the titanium dioxide is crushed at a specific powdering rate, and finally the titanium dioxide with high gloss and high hiding power is prepared. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1The finished product of the high-hiding inorganic-organic coated titanium dioxide white powder. DETAILED DESCRIPTION

[0044] The application will be described in detail below in conjunction with the examples: The application provides a high-hiding inorganic-organic coated titanium dioxide white powder, which is prepared by sanding and inorganic-organic coating under specific conditions, greatly improving the gloss and hiding power and other properties.

[0045] Example 1 The application provides a high-hiding inorganic-organic coated titanium dioxide white powder, which is obtained by sanding, aging with basic aluminum and acidic aluminum, and then organic coating of the rutile titanium dioxide; the particle size of the high-hiding inorganic-organic coated titanium dioxide white powder is 0.313 μm, the oil-phase whiteness is 95.96, the oil dispersibility is 6.75, the color reduction is 2060, and the oil absorption is 17.3 g / L. The gloss at 20° of the high-hiding inorganic-organic coated titanium dioxide white powder is 24.1, the gloss at 60° is 89.4, and the gloss at 85° is 97.2, and the hiding power of the high-hiding inorganic-organic coated titanium dioxide white powder is 75.35%.

[0046] The application also provides a preparation method of the high-hiding inorganic-organic coated titanium dioxide white powder, which comprises the following steps: Step 1, 750 g of rutile titanium dioxide and 40 ml (concentration 100 g / L) of sodium silicate aqueous solution are stirred at a speed of 300 rpm for 30 min to be dissolved in 1300 ml of desalted water to obtain a mixed solution, the mixed solution is sand-milled in a sand mill with a zirconium bead of 0.6 mm and a filling rate of 50% at a speed of 2000 rpm for 60 min, and then sieved with a 325 mesh sieve, and the sieved solution is diluted with desalted water to a concentration of 295 g / L of the rutile titanium dioxide under the condition of 300 rpm, and the pH value of the system is kept at 9 to obtain a premix slurry; Step 2, under the condition of continuous stirring at 300 rpm, 100 g / L of NaAlO2 solution (the amount of addition is 1.75% of the mass of the rutile titanium dioxide at this time) and 100 g / L of Al2(SO4)3 solution (the amount of addition is 1.55% of the mass of the rutile titanium dioxide at this time) are added to the premix slurry at 55 ℃ to perform primary aging, the pH value of the system is kept at 9 during the primary aging, and after 90 min of primary aging, the pH value of the system is adjusted to 6 with 200 g / L of sulfuric acid solution, and the stirring is continued for 120 min to perform secondary aging to obtain an aged slurry; Step 3, the slurry is filtered and the solid product is washed with deionized water until the conductivity of the filtrate is ≤100 us / cm, to obtain a filter cake, which is slurried with desalted water at 300 rpm for 60 min, then trimethylolpropane is added (the amount added is 0.4% of the mass of the rutile titanium dioxide at this time) and stirred at a speed of 300 rpm for 60 min, then the slurry is dried at 130°C for 8h, the dried product is crushed and then air-pulverized at 0.5 MPa, 150 Hz and a feeding rate of 150 Hz to obtain the high-hiding inorganic-organic coated titanium dioxide.

[0047] Example 2 The present embodiment provides a high-hiding inorganic-organic coated titanium dioxide, which is obtained by organic coating after sanding of rutile titanium dioxide and aging with basic aluminum and acidic aluminum; the particle size of the high-hiding inorganic-organic coated titanium dioxide is 0.335 μm, the oil-phase whiteness is 95.92, the oil dispersibility is 6.75, the color reduction is 2060, and the oil absorption is 17.8 g / L. The gloss at 20° of the high-hiding inorganic-organic coated titanium dioxide is 28.1, the gloss at 60° is 88.5, and the gloss at 85° is 99.5, and the hiding power of the high-hiding inorganic-organic coated titanium dioxide is 75.57%.

[0048] The present embodiment also provides a preparation method of the high-hiding inorganic-organic coated titanium dioxide, which comprises the following steps: Step 1, 750 g of rutile titanium dioxide and 30 ml (concentration 100 g / L) of sodium silicate aqueous solution are stirred at a speed of 500 rpm for 20 min and dissolved in 1500 ml of desalted water to obtain a mixed solution, which is ground in a sand mill with a zirconium bead filling rate of 80% at 2500 rpm for 45 min and then sieved with a 300 mesh sieve, and the sieved solution is diluted with desalted water at a speed of 500 rpm until the concentration of the rutile titanium dioxide is 280 g / L, and the pH value of the system is maintained at 10 to obtain a premixed slurry; Step 2, under the condition of continuous stirring at 500 rpm, 100 g / L of NaAlO2 solution (the amount added is 2% of the mass of the rutile titanium dioxide at this time) and 100 g / L of Al2(SO4)3 solution (the amount added is 1.8% of the mass of the rutile titanium dioxide at this time) are added to the premixed slurry at 40°C for primary aging, the pH value of the system is maintained at 10 during the primary aging, and after 120 min of primary aging, the pH value of the system is adjusted to 7 with 200 g / L of sulfuric acid solution, and the stirring is continued for 150 min for secondary aging to obtain an aged slurry; Step 3, the slurry is filtered and the solid product is washed with deionized water until the conductivity of the filtrate is ≤100 us / cm, to obtain a filter cake, which is slurried with desalted water at 500 rpm for 60 min, then trimethylolpropane is added (the amount added is 0.1% of the mass of the rutile titanium dioxide at this time) and stirred at a speed of 500 rpm for 60 min, then the slurry is dried at 150°C for 5h, the dried product is crushed and then air-powdered at 0.1 MPa and a feed rate of 100 Hz to obtain the high-hiding inorganic-organic coated titanium dioxide.

[0049] Example 3 The present example provides a high-hiding inorganic-organic coated titanium dioxide, which is obtained by organic coating after sanding rutile titanium dioxide and then aging with basic aluminum and acidic aluminum; the particle size of the high-hiding inorganic-organic coated titanium dioxide is 0.324 μm, the oil-phase whiteness is 95.98, the oil dispersibility is 6.75, the color reduction is 2070, and the oil absorption is 17.1 g / L. The gloss at 20° of the high-hiding inorganic-organic coated titanium dioxide is 22.5, the gloss at 60° is 87.9, and the gloss at 85° is 101.8, and the hiding power of the high-hiding inorganic-organic coated titanium dioxide is 76.49%.

[0050] The present example also provides a preparation method of the high-hiding inorganic-organic coated titanium dioxide, which comprises the following steps: Step 1, 750 g of rutile titanium dioxide and 40 ml (concentration 100 g / L) of sodium silicate aqueous solution are stirred at a speed of 300 rpm for 50 min and dissolved in 1300 ml of desalted water to obtain a mixed solution, the mixed solution is sand-milled in a sand mill with a zirconium bead of 0.8 mm and a filling rate of 50% at 2000 rpm for 75 min, and then sieved with a 350 mesh sieve, and the sieved solution is diluted with desalted water at a speed of 400 rpm until the concentration of the rutile titanium dioxide is 320 g / L, and the pH value of the system is maintained at 9 to obtain a premixed slurry; Step 2, under the condition of continuous stirring at 400 rpm, 120 g / L of NaAlO2 solution (the amount added is 1.75% of the mass of the rutile titanium dioxide at this time) and 120 g / L of Al2(SO4)3 solution (the amount added is 1.55% of the mass of the rutile titanium dioxide at this time) are added to the premixed slurry at 70°C for primary aging, the pH value of the system is maintained at 9 during the primary aging, and after 90 min of primary aging, the pH value of the system is adjusted to 6 with 180 g / L of sulfuric acid solution, and the stirring is continued for 180 min for secondary aging to obtain an aged slurry; Step 3, the slurry is filtered and the solid product is washed with deionized water until the conductivity of the filtrate is ≤100 us / cm, to obtain a filter cake, the filter cake is slurried with desalted water at 400 rpm for 100 min, then trimethylolpropane is added (the amount added is 0.5% of the mass of the rutile titanium dioxide at this time), stirred at a speed of 300 rpm for 90 min, then the slurry is dried at 100°C for 10 h, the dried product is crushed and then air-pulverized at 0.8 MPa, 100 Hz and a feed rate of 100 Hz to obtain the high-hiding inorganic-organic coated titanium dioxide pigment.

[0051] Example 4 The present example provides a high-hiding inorganic-organic coated titanium dioxide pigment, which is obtained by organic coating after sanding of rutile titanium dioxide and then aging with basic aluminum and acidic aluminum; the particle size of the high-hiding inorganic-organic coated titanium dioxide pigment is 0.345 μm, the oil-phase whiteness is 95.99, the oil dispersibility is 6.75, the color reduction is 2080, and the oil absorption is 18.0 g / L. The gloss at 20° of the high-hiding inorganic-organic coated titanium dioxide pigment is 28.1, the gloss at 60° is 89.6, and the gloss at 85° is 100.1, and the hiding power of the high-hiding inorganic-organic coated titanium dioxide pigment is 75.45%.

[0052] The present example also provides a preparation method of the high-hiding inorganic-organic coated titanium dioxide pigment, which comprises the following steps: Step 1, 750 g of rutile titanium dioxide and 40 ml (concentration 100 g / L) of a sodium silicate aqueous solution are stirred at a speed of 300 rpm for 30 min and dissolved in 1300 ml of desalted water to obtain a mixed solution, the mixed solution is sand-milled in a sand mill with a zirconium bead of 0.6 mm and a filling rate of the zirconium bead of 50% at 2000 rpm for 60 min, and then sieved with a 325 mesh sieve, and the sieved solution is diluted with desalted water at 300 rpm until the concentration of the rutile titanium dioxide is 295 g / L, and the pH value of the system is maintained at 9 to obtain a premixed slurry; Step 2, under the condition of continuous stirring at 300 rpm, 100 g / L of a NaAlO2 solution (the amount added is 1.75% of the mass of the rutile titanium dioxide at this time) and 100 g / L of an Al2(SO4)3 solution (the amount added is 1.55% of the mass of the rutile titanium dioxide at this time) are added to the premixed slurry at 55°C for primary aging, the pH value of the system is maintained at 9 during the primary aging, and after 90 min of primary aging, the pH value of the system is adjusted to 6 with a 200 g / L sulfuric acid solution, and the stirring is continued for 120 min for secondary aging to obtain an aged slurry; Step 3, the slurry is filtered and the solid product is washed with deionized water until the conductivity of the filtrate is ≤100 us / cm, to obtain a filter cake, which is slurried with desalted water at 300 rpm for 60 min, then trimethylolpropane is added (the amount added is 0.4% of the mass of the rutile titanium dioxide at this time) and stirred at a speed of 300 rpm for 60 min, then the slurry is dried at 130°C for 8 h, the dried product is crushed and then air-pulverized at 0.5 MPa, 150 Hz and a feeding rate of 150 Hz to obtain the high-hiding inorganic-organic coated titanium dioxide pigment.

[0053] Example 5 The present example provides a high-hiding inorganic-organic coated titanium dioxide pigment, which is obtained by organic coating after sanding of rutile titanium dioxide and aging with basic aluminum and acidic aluminum. The particle size of the high-hiding inorganic-organic coated titanium dioxide pigment is 0.319 μm, the oil-phase whiteness is 96.01, the oil dispersibility is 6.75, the color reduction is 2080, and the oil absorption is 17.6 g / L. The gloss at 20° of the high-hiding inorganic-organic coated titanium dioxide pigment is 23.8, the gloss at 60° is 87.2, and the gloss at 85° is 100.6. The hiding power of the high-hiding inorganic-organic coated titanium dioxide pigment is 75.34%.

[0054] The present example also provides a preparation method of the high-hiding inorganic-organic coated titanium dioxide pigment, which comprises the following steps: Step 1, 750 g of rutile titanium dioxide and 40 ml (concentration 100 g / L) of a sodium silicate aqueous solution are stirred at a speed of 300 rpm for 30 min and dissolved in 1300 ml of desalted water to obtain a mixed solution, which is ground in a sand mill with a zirconium bead of 0.6 mm and a filling rate of 50% at 2000 rpm for 60 min, and then sieved with a 325 mesh sieve. The sieved solution is diluted with desalted water at 300 rpm until the concentration of the rutile titanium dioxide is 295 g / L, and the pH value of the system is maintained at 9 to obtain a premixed slurry. Step 2, under the condition of continuous stirring at 300 rpm, 100 g / L of a NaAlO2 solution (the amount added is 1.75% of the mass of the rutile titanium dioxide at this time) and 100 g / L of an Al2(SO4)3 solution (the amount added is 1.55% of the mass of the rutile titanium dioxide at this time) are added to the premixed slurry at 55°C for primary aging, the pH value of the system is maintained at 9 during the primary aging, and after 90 min of primary aging, the pH value of the system is adjusted to 6 with a 200 g / L sulfuric acid solution, and the stirring is continued for 120 min for secondary aging to obtain an aged slurry. Step 3: Filter the matured slurry and wash the solid product with deionized water until the conductivity of the filtrate is ≤100 μS / cm to obtain a filter cake. After beating the filter cake with deionized water at 300 rpm for 60 min, add trimethylolpropane (0.4% of the mass of the rutile titanium dioxide at this time) and stir at 300 rpm for 60 min. Then, dry the slurry at 130°C for 8 h. After crushing the dried product, perform air-powdering at a feed rate of 0.5 MPa and 150 Hz to obtain the high-coverage inorganic-organic coated titanium dioxide.

[0055] Comparative Example 1 This comparative example provides a titanium dioxide powder, which is obtained by grinding rutile titanium dioxide sand and then organically coating it after aging with alkaline aluminum and acidic aluminum; the titanium dioxide powder has a particle size of 0.382 μm, an oil phase whiteness of 95.61, an oil dispersibility of 6.50, a tinting strength of 2060, and an oil absorption of 19.2 g / L; The titanium dioxide has a gloss of 20.2 at 20°, 78.6 at 60°, and 96.5 at 85°, and its hiding power is 74.92%.

[0056] This comparative example also provides a method for preparing the titanium dioxide, comprising the following steps: Step 1: Dissolve 750g of rutile titanium dioxide and 40ml (concentration 100g / L) of ammonium hexametaphosphate aqueous solution in 1300ml of demineralized water at 300rpm for 30min to obtain a mixture. Mill the mixture in a sand mill with 0.6mm zirconium beads at 2000rpm for 60min, and then sieve it through a 325-mesh sieve. Dilute the sieved solution with demineralized water at 300rpm to a concentration of 295g / L of rutile titanium dioxide, keeping the pH of the system at 9, to obtain a premixed slurry. Step 2: Under continuous stirring at 300 rpm, add 100 g / L NaAlO2 solution (1.75% of the mass of rutile titanium dioxide at this time) and 100 g / L Al2(SO4)3 solution (1.55% of the mass of rutile titanium dioxide at this time) to the premixed slurry at 55°C for a first maturation. During the first maturation, maintain the pH of the system at 9. After the first maturation for 90 min, adjust the pH of the system to 6 with 200 g / L sulfuric acid solution, and continue stirring for 120 min for a second maturation to obtain the matured slurry. Step 3: Filter the matured slurry and wash the solid product with deionized water until the conductivity of the filtrate is ≤100 μS / cm to obtain a filter cake. After beating the filter cake with deionized water at 300 rpm for 60 min, add trimethylolpropane (0.4% of the mass of the rutile titanium dioxide at this time) and stir at 300 rpm for 60 min. Then, dry the slurry at 130°C for 8 h. After crushing the dried product, pulverize it at a feed rate of 0.5 MPa and 150 Hz to obtain the titanium dioxide.

[0057] Comparative Example 2 This comparative example provides a titanium dioxide powder, which is obtained by grinding rutile titanium dioxide sand and then organically coating it after aging with alkaline aluminum and acidic aluminum. The titanium dioxide powder has a particle size of 0.391 μm, an oil phase whiteness of 95.52, an oil dispersibility of 6.25, a tinting strength of 2070, and an oil absorption of 19.1 g / L. The titanium dioxide has a gloss of 20.5 at 20°, 77.1 at 60°, and 97.2 at 85°, and its hiding power is 75.05%.

[0058] This comparative example also provides a method for preparing the titanium dioxide, comprising the following steps: Step 1: Dissolve 750g of rutile titanium dioxide and 40ml (concentration 100g / L) of sodium silicate aqueous solution in 1300ml of demineralized water at 300rpm for 30min to obtain a mixture. Then, mill the mixture in a sand mill with 1.2mm zirconium beads at 2000rpm for 60min and sieve it through a 325-mesh sieve. Dilute the sieved solution with demineralized water at 300rpm until the concentration of rutile titanium dioxide is 295g / L, while maintaining the pH of the system at 9 to obtain a premixed slurry. Step 2: Under continuous stirring at 300 rpm, add 100 g / L NaAlO2 solution (1.75% of the mass of rutile titanium dioxide at this time) and 100 g / L Al2(SO4)3 solution (1.55% of the mass of rutile titanium dioxide at this time) to the premixed slurry at 55°C for a first maturation. During the first maturation, maintain the pH of the system at 9. After the first maturation for 90 min, adjust the pH of the system to 6 with 200 g / L sulfuric acid solution, and continue stirring for 120 min for a second maturation to obtain the matured slurry. Step 3: Filter the matured slurry and wash the solid product with deionized water until the conductivity of the filtrate is ≤100 μS / cm to obtain a filter cake. After beating the filter cake with deionized water at 300 rpm for 60 min, add trimethylolpropane (0.4% of the mass of the rutile titanium dioxide at this time) and stir at 300 rpm for 60 min. Then, dry the slurry at 130°C for 8 h. After crushing the dried product, pulverize it at a feed rate of 0.5 MPa and 150 Hz to obtain the titanium dioxide.

[0059] Comparative Example 3 This comparative example provides a titanium dioxide powder, which is obtained by grinding rutile titanium dioxide sand and then organically coating it after aging with alkaline aluminum and acidic aluminum; the titanium dioxide powder has a particle size of 0.378 μm, an oil phase whiteness of 95.54, an oil dispersibility of 6.25, a tinting strength of 2060, and an oil absorption of 18.7 g / L; The titanium dioxide has a gloss of 19.9 at 20°, a gloss of 77.3 at 60°, and a gloss of 95.4 at 85°, and the hiding power of the titanium dioxide is 75.11%.

[0060] This comparative example also provides a method for preparing the titanium dioxide, comprising the following steps: Step 1: Dissolve 750g of rutile titanium dioxide and 40ml (concentration 100g / L) of sodium silicate aqueous solution in 1300ml of demineralized water at 300rpm for 30min to obtain a mixture. Mill the mixture in a sand mill with 0.6mm zirconium beads at 50% filling rate at 2000rpm for 60min, and then sieve it through a 325-mesh sieve. Dilute the sieved solution with demineralized water at 300rpm to a concentration of 295g / L of rutile titanium dioxide, and maintain the pH of the system at 9 to obtain a premixed slurry. Step 2: Under continuous stirring at 300 rpm, add 100 g / L NaAlO2 solution (1.75% of the mass of rutile titanium dioxide at this time) and 100 g / L Al2(SO4)3 solution (1.55% of the mass of rutile titanium dioxide at this time) to the premixed slurry at 30°C for a first maturation. During the first maturation, maintain the pH of the system at 9. After the first maturation for 90 min, adjust the pH of the system to 6 with 200 g / L sulfuric acid solution, and continue stirring for 120 min for a second maturation to obtain the matured slurry. Step 3: Filter the matured slurry and wash the solid product with deionized water until the conductivity of the filtrate is ≤100 μS / cm to obtain a filter cake. After beating the filter cake with deionized water at 300 rpm for 60 min, add trimethylolpropane (0.4% of the mass of the rutile titanium dioxide at this time) and stir at 300 rpm for 60 min. Then, dry the slurry at 130°C for 8 h. After crushing the dried product, pulverize it at a feed rate of 0.5 MPa and 150 Hz to obtain the titanium dioxide.

[0061] Comparative Example 4 This comparative example provides a titanium dioxide powder, which is obtained by grinding rutile titanium dioxide sand and then organically coating it after aging with alkaline aluminum and acidic aluminum; the titanium dioxide powder has a particle size of 0.370 μm, an oil phase whiteness of 95.60, an oil dispersibility of 6.25, a tinting strength of 2080, and an oil absorption of 19.0 g / L; The titanium dioxide has a gloss of 18.1 at 20°, a gloss of 75.3 at 60°, and a gloss of 94.9 at 85°, and the hiding power of the titanium dioxide is 74.82%.

[0062] This comparative example also provides a method for preparing the titanium dioxide, comprising the following steps: Step 1: Dissolve 750g of rutile titanium dioxide and 40ml (concentration 100g / L) of sodium silicate aqueous solution in 1300ml of demineralized water at 300rpm for 30min to obtain a mixture. Mill the mixture in a sand mill with 0.6mm zirconium beads at 50% filling rate at 2000rpm for 60min, and then sieve it through a 325-mesh sieve. Dilute the sieved solution with demineralized water at 300rpm to a concentration of 295g / L of rutile titanium dioxide, and maintain the pH of the system at 9 to obtain a premixed slurry. Step 2: Under continuous stirring at 300 rpm, add 100 g / L NaAlO2 solution (1.75% of the mass of rutile titanium dioxide at this time) and 100 g / L Al2(SO4)3 solution (1.55% of the mass of rutile titanium dioxide at this time) to the premixed slurry at 80°C for a first maturation. During the first maturation, maintain the pH of the system at 9. After the first maturation for 90 min, adjust the pH of the system to 6 with 200 g / L sulfuric acid solution, and continue stirring for 120 min for a second maturation to obtain the matured slurry. Step 3: Filter the matured slurry and wash the solid product with deionized water until the conductivity of the filtrate is ≤100 μS / cm to obtain a filter cake. After beating the filter cake with deionized water at 300 rpm for 60 min, add trimethylolpropane (0.4% of the mass of the rutile titanium dioxide at this time) and stir at 300 rpm for 60 min. Then, dry the slurry at 130°C for 8 h. After crushing the dried product, pulverize it at a feed rate of 0.5 MPa and 150 Hz to obtain the titanium dioxide.

[0063] Comparative Example 5 This comparative example provides a titanium dioxide powder, which is obtained by grinding rutile titanium dioxide sand and then organically coating it after aging with alkaline aluminum and acidic aluminum; the titanium dioxide powder has a particle size of 0.386 μm, an oil phase whiteness of 95.64, an oil dispersibility of 6.50, a tinting strength of 2080, and an oil absorption of 19.1 g / L; The titanium dioxide has a gloss of 19.6 at 20°, a gloss of 76.7 at 60°, and a gloss of 95.8 at 85°, and the hiding power of the titanium dioxide is 74.90%.

[0064] This comparative example also provides a method for preparing the titanium dioxide, comprising the following steps: Step 1: Dissolve 750g of rutile titanium dioxide and 40ml (concentration 100g / L) of sodium silicate aqueous solution in 1300ml of demineralized water at 300rpm for 30min to obtain a mixture. Mill the mixture in a sand mill with 0.6mm zirconium beads at 50% filling rate at 2000rpm for 60min, and then sieve it through a 325-mesh sieve. Dilute the sieved solution with demineralized water at 300rpm to a concentration of 295g / L of rutile titanium dioxide, and maintain the pH of the system at 9 to obtain a premixed slurry. Step 2: Under continuous stirring at 300 rpm, add 100 g / L Al2(SO4)3 solution (1.55% of the mass of rutile titanium dioxide at this time) to the premixed slurry at 55°C for a first curing time of 90 min. Then add 100 g / L NaAlO2 solution (1.75% of the mass of rutile titanium dioxide at this time) and continue stirring for 120 min for a second curing time to obtain a cured slurry. Step 3: Filter the matured slurry and wash the solid product with deionized water until the conductivity of the filtrate is ≤100 μS / cm to obtain a filter cake. After beating the filter cake with deionized water at 300 rpm for 60 min, add trimethylolpropane (0.4% of the mass of the rutile titanium dioxide at this time) and stir at 300 rpm for 60 min. Then, dry the slurry at 130°C for 8 h. After crushing the dried product, pulverize it at a feed rate of 0.5 MPa and 150 Hz to obtain the titanium dioxide.

[0065] Comparative Example 6 This comparative example provides a titanium dioxide powder, which is obtained by grinding rutile titanium dioxide sand and then organically coating it after aging with alkaline aluminum and acidic aluminum; the titanium dioxide powder has a particle size of 0.384 μm, an oil phase whiteness of 95.51, an oil dispersibility of 6.50, a tinting strength of 2070, and an oil absorption of 19.8 g / L; The titanium dioxide has a gloss of 19.7 at 20°, 76.9 at 60°, and 96.1 at 85°, and its hiding power is 74.94%.

[0066] This comparative example also provides a method for preparing the titanium dioxide, comprising the following steps: Step 1: Dissolve 750g of rutile titanium dioxide and 40ml (concentration 100g / L) of sodium silicate aqueous solution in 1300ml of demineralized water at 300rpm for 30min to obtain a mixture. Mill the mixture in a sand mill with 0.6mm zirconium beads at 50% filling rate at 2000rpm for 60min, and then sieve it through a 325-mesh sieve. Dilute the sieved solution with demineralized water at 300rpm to a concentration of 295g / L of rutile titanium dioxide, and maintain the pH of the system at 9 to obtain a premixed slurry. Step 2: Under continuous stirring at 300 rpm, add 100 g / L NaAlO2 solution (1.75% of the mass of rutile titanium dioxide at this time) and 100 g / L Al2(SO4)3 solution (1.55% of the mass of rutile titanium dioxide at this time) to the premixed slurry at 80°C for a first ripening. During the first ripening, maintain the pH of the system at 5.5. After the first ripening for 90 min, adjust the pH of the system to 6 with 200 g / L sulfuric acid solution, and continue stirring for 120 min for a second ripening to obtain the ripened slurry. Step 3: Filter the matured slurry and wash the solid product with deionized water until the conductivity of the filtrate is ≤100 μS / cm to obtain a filter cake. After beating the filter cake with deionized water at 300 rpm for 60 min, add trimethylolpropane (0.4% of the mass of the rutile titanium dioxide at this time) and stir at 300 rpm for 60 min. Then, dry the slurry at 130°C for 8 h. After crushing the dried product, pulverize it at a feed rate of 0.5 MPa and 150 Hz to obtain the titanium dioxide.

[0067] Comparative Example 7 This comparative example provides a titanium dioxide powder, which is obtained by grinding rutile titanium dioxide sand and then organically coating it after aging with alkaline aluminum and acidic aluminum; the titanium dioxide powder has a particle size of 0.391 μm, an oil phase whiteness of 95.60, a tinting strength of 1980, and an oil absorption of 20.3 g / L; The titanium dioxide has a gloss of 15.2 at 20°, a gloss of 69.5 at 60°, and a gloss of 92.5 at 85°, and the hiding power of the titanium dioxide is 73.21%.

[0068] This comparative example also provides a method for preparing the titanium dioxide, comprising the following steps: Step 1: Dissolve 750g of rutile titanium dioxide and 40ml (concentration 100g / L) of sodium silicate aqueous solution in 1300ml of demineralized water at 300rpm for 30min to obtain a mixture. Mill the mixture in a sand mill with 0.6mm zirconium beads at 50% filling rate at 2000rpm for 60min, and then sieve it through a 325-mesh sieve. Dilute the sieved solution with demineralized water at 300rpm to a concentration of 295g / L of rutile titanium dioxide, and maintain the pH of the system at 9 to obtain a premixed slurry. Step 2: Under continuous stirring at 300 rpm, add 100 g / L NaAlO2 solution (1.75% of the mass of rutile titanium dioxide at this time) and 100 g / L Al2(SO4)3 solution (1.55% of the mass of rutile titanium dioxide at this time) to the premixed slurry at 55°C for a first maturation. During the first maturation, maintain the pH of the system at 9. After the first maturation for 90 min, adjust the pH of the system to 6 with 200 g / L sulfuric acid solution, and continue stirring for 120 min for a second maturation to obtain the matured slurry. Step 3: Filter the matured slurry and wash the solid product with deionized water until the conductivity of the filtrate is ≤100us / cm to obtain a filter cake. Dry the filter cake at 130℃ for 8 hours. After the dried product is crushed, it is gas-powdered at a feed rate of 0.5MPa and 150Hz to obtain the titanium dioxide.

[0069] Comparative Example 8 This comparative example provides a titanium dioxide, which is obtained by grinding rutile titanium dioxide sand and then organically coating it after aging with alkaline aluminum and acidic aluminum. The titanium dioxide has a particle size of 0.389 μm, an oil phase whiteness of 95.65, an oil dispersibility of 6.25, a tinting strength of 2060, and an oil absorption of 19.3 g / L. The titanium dioxide has a gloss of 17.6 at 20°, 75.8 at 60°, and 95.2 at 85°, and its hiding power is 75.01%.

[0070] This comparative example also provides a method for preparing the titanium dioxide, comprising the following steps: Step 1: Dissolve 750g of rutile titanium dioxide and 40ml (concentration 100g / L) of ammonium hexametaphosphate aqueous solution in 1300ml of demineralized water at 300rpm for 30min to obtain a mixture. Mill the mixture in a sand mill with 0.6mm zirconium beads at 2000rpm for 60min, and then sieve it through a 325-mesh sieve. Dilute the sieved solution with demineralized water at 300rpm to a concentration of 295g / L of rutile titanium dioxide, keeping the pH of the system at 9, to obtain a premixed slurry. Step 2: Under continuous stirring at 300 rpm, add 100 g / L NaAlO2 solution (1.75% of the mass of rutile titanium dioxide at this time) and 100 g / L Al2(SO4)3 solution (1.55% of the mass of rutile titanium dioxide at this time) to the premixed slurry at 55°C for a first maturation. During the first maturation, maintain the pH of the system at 9. After the first maturation for 90 min, adjust the pH of the system to 6 with 200 g / L sulfuric acid solution, and continue stirring for 120 min for a second maturation to obtain the matured slurry. Step 3: Filter the matured slurry and wash the solid product with deionized water until the conductivity of the filtrate is ≤100 μS / cm to obtain a filter cake. After beating the filter cake with deionized water at 300 rpm for 60 min, add trimethylolpropane (0.4% of the mass of the rutile titanium dioxide at this time) and stir at 300 rpm for 60 min. Then, dry the slurry at 130°C for 8 h. After crushing the dried product, pulverize it by air at a feed rate of 0.2 MPa and 170 Hz to obtain the titanium dioxide.

[0071] The method for maintaining pH in this invention is as follows: when the solution pH is greater than a predetermined value, 100 g / L aluminum sulfate is added for adjustment; when the solution pH is less than a predetermined value, 100 g / L sodium aluminate is added for adjustment.

[0072] Table 1 shows the performance of titanium dioxide in this embodiment.

[0073] Table 2 shows the performance of titanium dioxide in this comparative example.

[0074] The testing standard for oil phase whiteness in this invention is GB / T5211.20-1999, the testing standard for oil dispersibility is GB / T21868.5-2008, the testing standard for tinting strength is GB / T5211.16-2007, and the testing standard for oil absorption is GB / T5211.15-2014. The gloss test conditions are as follows: the sample is mixed with a polyurethane polymer and coated into a film, and then tested using a gloss meter. The hiding power test conditions are as follows: the sample is mixed with a polyurethane polymer and coated into a film, and then tested using a colorimeter.

[0075] As shown in Tables 1 and 2, in the presence of silicate ions in sodium silicate, the silicate ions adsorb onto the surface of rutile titanium dioxide, increasing the negative charge density on the surface of rutile titanium dioxide and forming an electric double layer. This makes it difficult for rutile titanium dioxide particles to agglomerate due to electrostatic repulsion, thus improving the uniformity of dispersion of rutile titanium dioxide particles in the slurry. Therefore, the prepared titanium dioxide has good dispersibility. At the same time, the size and particle size of the zirconium beads in the sand mill concentrate the energy on individual rutile titanium dioxide particles rather than agglomerates during the sand milling process, thereby more efficiently milling the rutile titanium dioxide particles to the target particle size range. The milled particles are uniform in size, resulting in high whiteness, low oil absorption, and excellent gloss and hiding power of the prepared titanium dioxide. In Comparative Example 1, due to the different types of dispersants, the dispersion effect of rutile titanium dioxide was reduced compared to the present invention, resulting in poor dispersibility of the final titanium dioxide. In Comparative Example 2, the particle size of zirconium beads was increased during the sand milling process. Similarly, due to the increased porosity between the sand milled zirconium beads, the dispersibility of rutile titanium dioxide became poor. The large particles of titanium dioxide made the surface uneven and the gloss insufficient. Comparative Examples 3 and 4 respectively decreased and increased the inorganic coating temperature of rutile titanium dioxide. When the temperature was too low, the Brownian motion speed of the boehmite particles formed by aluminum salts during the inorganic coating process was slow, and the tendency of homogeneous nucleation was greater than that of heterogeneous nucleation. This resulted in larger particle agglomeration and adsorption on the surface of titanium dioxide particles, leading to uneven and discontinuous coating layers and poor coating effect. When the temperature was too high, the Brownian motion of the boehmite particles formed by aluminum salts accelerated sharply, and the particles deposited on the surface of titanium dioxide particles too quickly, which easily led to agglomeration, resulting in uneven coating layers and poor coating effect. In Comparative Example 5, the alkaline aluminum salt and acidic aluminum salt were not added simultaneously in a co-current manner. Instead, the acidic aluminum salt was added first, followed by the alkaline aluminum salt. This caused the pH value in the system to change from acidic to alkaline, which hindered the formation of boehmite particles and ultimately resulted in poor gloss of the titanium dioxide. Although both alkaline aluminum and acidic aluminum salt solutions were added to Comparative Example 6, the pH during its first aging process was still 5.5, which is acidic, consistent with Comparative Example 5. As a result, the gloss and hiding power of the titanium dioxide obtained decreased. In Comparative Example 7, the lack of organic coating significantly reduced the gloss and hiding power of the titanium dioxide. In Comparative Example 8, the changes in the pressure and rate of the air-powder resulted in uneven particle size distribution of titanium dioxide during air-powdering, which affected the performance of titanium dioxide.

[0076] As can be seen from the above, the high-coverage inorganic-organic coated titanium dioxide of the present invention has a wide range of applications, low cost, and a very high market prospect.

[0077] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other way. Any modifications or equivalent changes made based on the technical essence of the present invention shall still fall within the scope of protection claimed by the present invention.

Claims

1. A high-coverage inorganic-organic coated titanium dioxide, characterized in that, The high-coverage inorganic-organic coated titanium dioxide is obtained by grinding rutile titanium dioxide sand, followed by aging with alkaline aluminum and acidic aluminum, and then organically coating it. The high-coverage inorganic-organic coated titanium dioxide has a particle size of 0.30-0.35μm, an oil phase whiteness of 95-97, an oil dispersibility of 6.75, a tinting strength of 2060-2080, and an oil absorption of 17-18g / L. The high-coverage inorganic-organic coated titanium dioxide has a gloss of 22-29 at 20°, 87-90 at 60°, and 97-102 at 85°, and its hiding power is 75-77%.

2. A method for preparing the high-coverage inorganic-organic coated titanium dioxide according to claim 1, characterized in that, Includes the following steps: Step 1: Dissolve rutile titanium dioxide and dispersant in demineralized water to obtain a mixture. Grind the mixture in a sand mill and then sieve it. After sieving, dilute and maintain the pH to obtain a premixed slurry. Step 2: Under continuous stirring, the premixed slurry is heated and alkaline aluminum salt solution and acidic aluminum salt solution are added for primary maturation. Then, the pH of the system is adjusted with acid solution and stirring is continued for secondary maturation to obtain maturated slurry. Step 3: Filter the matured slurry and wash the solid product with deionized water to obtain a filter cake. Pulverize the filter cake, add organic matter and stir, then dry, pulverize and mix with air powder to obtain the high-coverage inorganic-organic coated titanium dioxide.

3. The preparation method according to claim 2, characterized in that, The dispersant in step 1 is sodium silicate.

4. The preparation method according to claim 2, characterized in that, In step 1, the sand mill is filled with zirconium beads, the zirconium beads have a particle size of 0.4-0.8 mm, and the zirconium bead filling rate is 50-80%.

5. The preparation method according to claim 2, characterized in that, The mesh size of the sieve in step 1 is 300-350 mesh.

6. The preparation method according to claim 2, characterized in that, In step 1, the pH value is maintained at 9-10.

5.

7. The preparation method according to claim 2, characterized in that, The heating temperature in step 2 is 40-70℃.

8. The preparation method according to claim 2, characterized in that, The alkaline aluminum salt in the alkaline aluminum salt solution in step 2 is one or both of sodium aluminate or potassium aluminate.

9. The preparation method according to claim 2, characterized in that, The acidic aluminum salt in the acidic aluminum salt solution in step 2 is one or more of aluminum nitrate, aluminum sulfate, and aluminum chloride.

10. An ink, characterized in that, The raw materials for the ink include the high-coverage inorganic-organic coated titanium dioxide as described in claim 1.

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