Preparation method of weather-resistant titanium dioxide for ABS plastic

Abstract

The application belongs to the technical field of titanium white powder manufacturing, and particularly relates to a preparation method of weather-resistant titanium white powder for ABS plastic. The application is coated with alumina and silicon dioxide, the dense aluminum film inhibits the photocatalytic decomposition of ABS resin by titanium dioxide, the silicon dioxide composite coating has high physical strength and acid resistance, and provides a binding site for subsequent organic coating agents, so that the prepared titanium white powder has small particle size, uniform distribution, high compatibility with ABS resin, a flexible transition layer is formed at the interface between the siloxane flexible chain segment on the surface of the titanium white powder and the ABS resin, the flexible chain segment is deformed to dissipate energy when external force acts, the interface is prevented from debonding, and the prepared weather-resistant ABS product has excellent mechanical properties and weather resistance. Hydroxyl-terminated polysiloxane is introduced into the ABS resin, the hydroxyl groups are directionally adsorbed on the surface of the titanium white powder through hydrogen bond action, hard agglomeration between titanium white powders is reduced, the viscosity of the system is reduced, and the processing fluidity is improved.

Description

Technical Field

[0001] This invention belongs to the field of titanium dioxide manufacturing technology, specifically relating to a method for preparing weather-resistant titanium dioxide for ABS plastics. Background Technology

[0002] Acrylonitrile-butadiene-styrene copolymer resin (ABS) possesses characteristics such as high gloss, high rigidity, and excellent impact resistance. It also offers advantages such as ease of processing and coating, making it widely used in the casing materials of various household appliances. ABS resin contains a butadiene rubber component, which is prone to oxidation and breakage, leading to yellowing, reduced gloss, decreased mechanical properties, and shortened service life. Titanium dioxide is the most crucial white pigment and UV shielding agent in ABS resin, used to provide hiding power, whiteness, and protect the resin from photoaging. Titanium dioxide is mainly divided into rutile and anatase types. Rutile titanium dioxide has better thermal stability, refractive index, and weather resistance. However, unmodified titanium dioxide has strong surface hydrophilicity and high surface free energy, resulting in uneven dispersion and agglomeration in plastics, which reduces the mechanical strength of ABS plastic products.

[0003] Chinese invention patent CN110669358B discloses a titanium dioxide for plastics and inks and its preparation method, including the following steps: pretreatment of rutile titanium dioxide by pulping, grinding, and grading; inorganic coating with zinc oxide and aluminum oxide; further treatment; and finally organic coating to obtain the product. The titanium dioxide for plastics and inks prepared by this invention has good weather resistance and gloss, which can well meet the requirements of subsequent use. However, the existing technology has a technical problem: it does not improve the weather resistance of titanium dioxide in ABS resin through improvements to the titanium dioxide raw materials and core powder preparation process. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing weather-resistant titanium dioxide for ABS plastics, which solves the technical problem in the prior art that there is no improvement on the raw materials and core powdering process of titanium dioxide to further improve the weather resistance of titanium dioxide in ABS resin.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: The preparation method of weather-resistant titanium dioxide for ABS plastic includes the following steps: S1. Acid hydrolysis: Using ilmenite as raw material, ilmenite is added to a ball mill and ball-milled to obtain ilmenite powder. The ilmenite powder is added to sulfuric acid for acid hydrolysis, iron powder is added for reduction, polyacrylamide precipitant is added to settle impurities, filtered, ferrous sulfate is removed by low-temperature crystallization, and concentrated to obtain crude titanium sulfate solution. S2. Add crude titanium sulfate solution to constant temperature hot water, heat up and mature, filter and collect solid to obtain crude metatitanic acid, wash crude metatitanic acid with water, add salt treatment agent, filter by pressure to obtain filter cake, calcine filter cake, cool and grind to obtain crude titanium dioxide. S3. Pretreatment: Add crude titanium dioxide to a pulping tank, add deionized water and dispersant, pulp, sieve, and obtain slurry; S4. Inorganic coating: Sodium aluminate is added to the slurry, sulfuric acid is added dropwise to adjust the pH, the temperature is raised and aged, the solid is collected by filtration and then added to deionized water to obtain a modified slurry, sodium silicate is added dropwise, sodium hydroxide is added dropwise to adjust the pH, the temperature is raised and modified, the solid is collected by filtration, washed and dried to obtain inorganic coated titanium dioxide. S5. Organic coating: Add A-151 silane coupling agent to deionized water, add inorganic coated titanium dioxide, heat to modify, filter to collect solid, wash, and dry and pulverize by airflow to obtain weather-resistant titanium dioxide for ABS plastic.

[0006] Preferably, the chemical composition of ilmenite in S1 is as follows: titanium dioxide 50-54%, ferrous oxide 33-36%, iron oxide 5-6%, silicon dioxide 4-5%, aluminum oxide 1.5-2%, calcium oxide 0.6-0.8%, magnesium oxide 1.3-1.6%, sulfur 0.05-0.08%, and phosphorus 0.01-0.03%.

[0007] Preferably, in step S1, the ball milling rate of ilmenite powder to a 200-325 mesh sieve is greater than 90%, the mass ratio of ilmenite powder to sulfuric acid is 1:1.3-1.5, acid hydrolysis is carried out at 150-180℃ for 1-3 hours, the sulfuric acid concentration is maintained between 85-98 wt% during acid hydrolysis, the amount of iron powder is 2-3% of the mass of ilmenite, reduction is carried out until the color of the titanium solution changes from dark brown to reddish-purple, the amount of polyacrylamide precipitant added is 5-10% of the mass of ilmenite, crystallization is carried out at 10-20℃, and the titanium content of the crude titanium sulfate solution is 200-220 g / L.

[0008] Preferably, the volume ratio of crude titanium sulfate solution to constant temperature hot water in S2 is 20~23:100. It is added dropwise to constant temperature hot water at 95~97℃, and then heated to 99~102℃ under a slight boiling state for 30~50 minutes. A sample is then dropped into deionized water to check whether it turns white and gray spots appear. The temperature is then raised to 102~105℃ for 2~4 hours.

[0009] Preferably, the salt treatment agent in S2 is prepared by mixing phosphoric acid, zinc oxide, potassium carbonate and aluminum sulfate in a mass ratio of 2:3~5:2:1. The amount of salt treatment agent added is 0.8~1.2% of the mass of crude metatitanic acid. The mixture is heated to 400~500℃ and calcined for 0.5~1h, then heated to 700~800℃ and calcined for 1~2h, and finally heated to 900~950℃ and held for 10~30min. The mixture is then ground until the passing rate of a 300-mesh sieve is greater than 90%.

[0010] Preferably, the dispersing agent in S3 is any one or a combination of carboxymethyl cellulose, monoisopropanolamine, and polycarboxylate dispersant. The amount of dispersing agent added is 0.1-1% of the mass of crude titanium dioxide. The mixture is pulped at 1500-2500 rpm for 1-2 hours and then passed through a 400-500 mesh sieve to obtain a slurry with a titanium content of 300-350 g / L.

[0011] Preferably, in step S4, the amount of sodium aluminate added is 0.5-2% of the slurry mass, sulfuric acid is added dropwise to adjust the pH to 4.5-5.5, the temperature is raised to 70-80℃ and aged for 1-2 hours, the titanium content of the modified slurry is 300-350 g / L, the amount of sodium silicate added is 5-10% of the modified slurry mass, sodium hydroxide is added dropwise to adjust the pH to 8.5-9.5, the modification is carried out at 50-60℃ for 1-2 hours, washed with deionized water, and dried at 50-60℃.

[0012] Preferably, in step S5, the mass ratio of A-151 silane coupling agent, deionized water, and inorganic coated titanium dioxide is 4~6:100:30~35. The mixture is reacted at 80~90℃ for 1~2 hours, washed with deionized water, and dried and pulverized with an air flow rate of 15~25m / s. The inlet air temperature is 180~200℃, and the outlet air temperature is 110~120℃.

[0013] A method for preparing weather-resistant titanium dioxide for ABS plastics, which is then used to prepare weather-resistant ABS, includes the following steps: S11. Grind the ABS resin, sieve it, dry it, and set it aside. S12. Add ABS resin, weather-resistant titanium dioxide, ultraviolet absorber, and antioxidant to a high-speed mixer and stir to mix. Then add polysiloxane and stir to obtain a mixed powder. S13. The mixed powder is added to a twin-screw extruder for melt extrusion, pelletized, and cooled to obtain weather-resistant ABS.

[0014] Preferably, in step S11, the grinding balls are ball-milled at a speed of 100-300 rpm for 4-6 hours, the grinding balls are zirconia balls, the ball-to-material ratio is 10-15:1, the balls are passed through a 200-300 mesh sieve, and dried at 60-70℃.

[0015] Preferably, in step S12, the mass ratio of ABS resin, weather-resistant titanium dioxide for ABS plastic, ultraviolet absorber, antioxidant, and polysiloxane is 100:3~6:0.3~0.5:0.5~1.5:0.5~2. The mixture is stirred at 300~500 rpm for 30~50 min, and after adding the polysiloxane, it is stirred at 1000~2000 rpm for 20~40 min.

[0016] Preferably, in S12, the polysiloxane is a hydroxyl-terminated polysiloxane, the ultraviolet absorber is any one or a combination of UV-9 ultraviolet absorber, UV-531 ultraviolet absorber, and UV-328 ultraviolet absorber, and the antioxidant is prepared by mixing antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1.

[0017] Preferably, in step S13, the temperature is raised to 200~220°C for melt extrusion.

[0018] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. This invention increases the contact range between sulfuric acid and ilmenite by ball milling, ensuring titanium extraction rate and reducing the content of impurities such as iron and calcium. After salt treatment, a zinc phosphate glass phase is formed in the early stage of calcination, inhibiting titanium dioxide grain growth and sintering. The introduction of potassium ions promotes rutile transformation, which is beneficial for obtaining titanium dioxide powder with uniform particle size and suitable specific surface area. The alumina and silica composite coating, with the aluminum film densely covering the titanium dioxide surface, inhibits the photocatalytic decomposition of ABS resin by titanium dioxide. The silica composite coating has high physical strength and acid resistance, providing binding sites for subsequent organic coating agents. The organic coating introduces vinyl groups, which can match the styrene and butadiene segments of ABS resin, improving the compatibility of titanium dioxide in ABS resin. The titanium dioxide intermediate product obtained by this invention has less and smaller particle size, good dispersibility in the ABS resin matrix, and no significant impact on the material's impact resistance.

[0019] 2. This invention introduces hydroxyl-terminated polysiloxane into ABS resin and weather-resistant titanium dioxide prepared by the method provided by this invention. The hydroxyl groups in the polysiloxane are directionally adsorbed onto the surface of the titanium dioxide through hydrogen bonding, reducing hard agglomeration between titanium dioxide particles, lowering the viscosity of the system, and improving processing fluidity. The titanium dioxide prepared by this invention has a small particle size and uniform distribution, which improves its compatibility with ABS resin. The flexible siloxane segments on the surface of the titanium dioxide form a flexible transition layer at the interface with the ABS resin. When external force is applied, the flexible segments deform and dissipate energy, avoiding interface debonding. This results in weather-resistant ABS products with both excellent mechanical properties and weather resistance. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] The present invention relates to the chemical composition of ilmenite as follows: titanium dioxide 53.6%, ferrous oxide 33.17%, iron oxide 5.3%, silicon dioxide 4.2%, aluminum oxide 1.6%, calcium oxide 0.65%, magnesium oxide 1.4%, sulfur 0.066%, and phosphorus 0.014%.

[0022] The ABS resin involved in this invention is PA-709, with a melt flow index of 6 mL / (10 min) at 220℃ (10 kg), a tensile strength of 35 MPa, and an impact strength of 38 kJ / m. 2 The polycarboxylate dispersant is model XY-19; the polysiloxane is model RTV-107.

[0023] Example 1: The preparation method of weather-resistant titanium dioxide for ABS plastic in this example includes the following steps: S1. Acid hydrolysis: Using ilmenite as raw material, ilmenite is added to a ball mill and ball-milled until the passing rate of a 325-mesh sieve is greater than 90% to obtain ilmenite powder. 1 t of ilmenite powder is added to 1.5 t of sulfuric acid and acid hydrolyzed at 180℃ for 3 h. During the acid hydrolysis process, the sulfuric acid concentration is monitored and maintained at 98 wt%. 30 kg of iron powder is added to reduce the titanium solution until the color of the titanium solution changes from dark brown to reddish-purple. 100 kg of polyacrylamide flocculant is added to settle impurities. After filtration, the solution is crystallized at 20℃ to remove ferrous sulfate. The titanium content is concentrated to 220 g / L to obtain crude titanium sulfate solution. S2. Add 220L of crude titanium sulfate solution to 1000L of 97℃ constant temperature hot water, heat to 102℃ and mature for 50min at a slight boiling state. Take a sample and drop it into deionized water to check if it turns white and gray spots appear. Heat to 105℃ and mature for 4h. Filter and collect the solid to obtain crude metatitanic acid. Wash the crude metatitanic acid with water and add a salt treatment agent prepared by mixing phosphoric acid, zinc oxide, potassium carbonate and aluminum sulfate in a mass ratio of 2:5:2:1. The amount of salt treatment agent added is 1.2% of the mass of crude metatitanic acid. Filter to obtain filter cake. Heat the filter cake to 500℃ and calcine for 1h, then heat to 800℃ and calcine for 2h. Finally, heat to 950℃ and hold for 30min. After cooling, grind until the passing rate of a 300 mesh sieve is greater than 90% to obtain crude titanium dioxide. S3. Pretreatment: Add 1 t of crude titanium dioxide to a pulping tank, add deionized water and 1 kg of carboxymethyl cellulose, and pulp at 2500 rpm for 2 hours. Pass through a 400-mesh sieve to obtain a slurry with a titanium content of 350 g / L. S4. Inorganic Coating: 20 kg of sodium aluminate was added to 1 t of slurry, sulfuric acid was added dropwise to adjust the pH to 5.5, the temperature was raised to 80℃ and aged for 2 h, the solid was collected by filtration and then added to deionized water to obtain a modified slurry with a titanium content of 350 g / L. 100 kg of sodium silicate was added dropwise to 1 t of modified slurry, sodium hydroxide was added dropwise to adjust the pH to 9.5, the modification was carried out at 60℃ for 2 h, washed with deionized water, and dried at 60℃ to obtain inorganic coated titanium dioxide. S5. Organic Coating: Add 50 kg of A-151 silane coupling agent to 1 t of deionized water, add 350 kg of inorganic coated titanium dioxide, react at 90℃ for 2 h, filter to collect the solid, wash with deionized water, dry and pulverize with an air flow rate of 25 m / s, with an inlet air temperature of 200℃ and an outlet air temperature of 120℃ to obtain weather-resistant titanium dioxide for ABS plastic.

[0024] The method for preparing weather-resistant titanium dioxide for ABS plastic in this embodiment yields weather-resistant titanium dioxide for use in the preparation of weather-resistant ABS. The preparation method includes the following steps: S11. Grind the ABS resin at 300 rpm for 6 hours using zirconia balls with a ball-to-material ratio of 15:1. Pass the mixture through a 300-mesh sieve and dry it at 70°C for later use. S12. Add 100kg of ABS resin, 6kg of weather-resistant titanium dioxide for ABS plastic, 0.5kg of UV-328 ultraviolet absorber, and 1.5kg of antioxidant prepared by mixing antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1 into a high-speed mixer and mix at 500rpm for 50min. Then add 2kg of polysiloxane and stir at 2000rpm for 40min to obtain a mixed powder. S13. Add the mixed powder to a twin-screw extruder, heat to 220°C, melt and extrude, granulate, and cool to obtain weather-resistant ABS.

[0025] Example 2, the preparation method of weather-resistant titanium dioxide for ABS plastic in this example includes the following steps: S1. Acid hydrolysis: Using ilmenite as raw material, ilmenite is added to a ball mill and ball-milled until the passing rate of a 200-mesh sieve is greater than 90% to obtain ilmenite powder. 1 t of ilmenite powder is added to 1.3 t of sulfuric acid and acid hydrolyzed at 150℃ for 3 h. During the acid hydrolysis process, the sulfuric acid concentration is monitored and maintained above 85 wt%. 20 kg of iron powder is added to reduce the titanium solution until the color of the titanium solution changes from dark brown to reddish-purple. 80 kg of polyacrylamide flocculant is added to settle impurities. After filtration, the solution is crystallized at 15℃ to remove ferrous sulfate. The titanium content is concentrated to 210 g / L to obtain crude titanium sulfate solution. S2. Add 200L of crude titanium sulfate solution to 1000L of 95℃ constant temperature hot water, heat to 100℃ and mature for 30min under a slight boiling state. Take a sample and drop it into deionized water to check whether it turns white and gray spots appear. Heat to 103℃ and mature for 4h. Filter and collect the solid to obtain crude metatitanic acid. Wash the crude metatitanic acid with water and add a salt treatment agent prepared by mixing phosphoric acid, zinc oxide, potassium carbonate and aluminum sulfate in a mass ratio of 2:4:2:1. The amount of salt treatment agent added is 1% of the mass of crude metatitanic acid. Filter press to obtain filter cake. Heat the filter cake to 450℃ and calcine for 0.5h, then heat to 750℃ and calcine for 2h. Finally, heat to 920℃ and hold for 30min. After cooling, grind until the passing rate of a 300-mesh sieve is greater than 90% to obtain crude titanium dioxide. S3. Pretreatment: Add 1 t of crude titanium dioxide to a pulping tank, add deionized water and 8 kg of polycarboxylate dispersant, and pulp at 2000 rpm for 2 hours. Pass through a 400-mesh sieve to obtain a slurry with a titanium content of 300 g / L. S4. Inorganic coating: Add 5 kg of sodium aluminate to 1 t of slurry, add sulfuric acid to adjust the pH to 4.5, heat to 70℃ and age for 1 h, filter and collect the solid, then add deionized water to obtain a modified slurry with a titanium content of 300 g / L. Add 50 kg of sodium silicate to 1 t of modified slurry, add sodium hydroxide to adjust the pH to 8.5, modify at 60℃ for 1 h, wash with deionized water, and dry at 50℃ to obtain inorganic coated titanium dioxide. S5. Organic Coating: Add 40 kg of A-151 silane coupling agent to 1 t of deionized water, add 300 kg of inorganic coated titanium dioxide, react at 80℃ for 2 h, filter to collect the solid, wash with deionized water, dry and pulverize with an air flow rate of 15 m / s, with an inlet air temperature of 180℃ and an outlet air temperature of 110℃ to obtain weather-resistant titanium dioxide for ABS plastic.

[0026] The method for preparing weather-resistant titanium dioxide for ABS plastic in this embodiment yields weather-resistant titanium dioxide for use in the preparation of weather-resistant ABS. The preparation method includes the following steps: S11. Grind the ABS resin at 100 rpm for 4 hours. The grinding balls are zirconia balls with a ball-to-material ratio of 10:1. Pass the mixture through a 200-mesh sieve and dry it at 60℃ for later use. S12. Add 100kg of ABS resin, 3kg of weather-resistant titanium dioxide for ABS plastic, 0.3kg of UV-531 ultraviolet absorber, and 0.5kg of antioxidant prepared by mixing antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1 into a high-speed mixer and mix at 300rpm for 30min. Then add 0.5kg of polysiloxane and stir at 1000rpm for 20min to obtain a mixed powder. S13. Add the mixed powder to a twin-screw extruder, heat to 200°C, melt and extrude, granulate, and cool to obtain weather-resistant ABS.

[0027] Example 3, the preparation method of weather-resistant titanium dioxide for ABS plastic in this example includes the following steps: S1. Acid hydrolysis: Using ilmenite as raw material, ilmenite is added to a ball mill and ball-milled until the passing rate of a 300-mesh sieve is greater than 90% to obtain ilmenite powder. 1 t of ilmenite powder is added to 1.4 t of sulfuric acid and acid hydrolyzed at 170℃ for 2 h. During the acid hydrolysis process, the sulfuric acid concentration is monitored and maintained above 90 wt%. 25 kg of iron powder is added to reduce the titanium solution until the color of the titanium solution changes from dark brown to reddish-purple. 50 kg of polyacrylamide flocculant is added to settle impurities. After filtration, the solution is crystallized at 10℃ to remove ferrous sulfate. The titanium content is concentrated to 200 g / L to obtain crude titanium sulfate solution. S2. Add 200L of crude titanium sulfate solution to 1000L of 95℃ constant temperature hot water, heat to 99℃ and mature for 50min at a slight boiling state. Take a sample and drop it into deionized water to check if it turns white and gray spots appear. Heat to 102℃ and mature for 4h. Filter and collect the solid to obtain crude metatitanic acid. Wash the crude metatitanic acid with water and add a salt treatment agent prepared by mixing phosphoric acid, zinc oxide, potassium carbonate and aluminum sulfate in a mass ratio of 2:3:2:1. The amount of salt treatment agent added is 0.8% of the mass of crude metatitanic acid. Filter press to obtain filter cake. Heat the filter cake to 400℃ and calcine for 0.5h, then heat to 700℃ and calcine for 1h. Finally, heat to 900℃ and hold for 10min. After cooling, grind until the passing rate of a 300-mesh sieve is greater than 90% to obtain crude titanium dioxide. S3. Pretreatment: Add 1 t of crude titanium dioxide to a pulping tank, add deionized water and 1 kg of monoisopropanolamine, and pulp at 1500 rpm for 2 hours. Pass through a 400-mesh sieve to obtain a slurry with a titanium content of 300 g / L. S4. Inorganic coating: 10 kg of sodium aluminate was added to 1 t of slurry, sulfuric acid was added dropwise to adjust the pH to 5, the temperature was raised to 75℃ and aged for 1.5 h, the solid was collected by filtration and then added to deionized water to obtain a modified slurry with a titanium content of 300 g / L. 50 kg of sodium silicate was added dropwise to 1 t of modified slurry, sodium hydroxide was added dropwise to adjust the pH to 9, the modification was carried out at 55℃ for 1.5 h, washed with deionized water, and dried at 55℃ to obtain inorganic coated titanium dioxide. S5. Organic Coating: Add 50 kg of A-151 silane coupling agent to 1 t of deionized water, add 300 kg of inorganic coated titanium dioxide, react at 85℃ for 1.5 h, filter to collect the solid, wash with deionized water, dry and pulverize with an air flow rate of 20 m / s, with an inlet air temperature of 190℃ and an outlet air temperature of 115℃ to obtain weather-resistant titanium dioxide for ABS plastic.

[0028] The method for preparing weather-resistant titanium dioxide for ABS plastic in this embodiment yields weather-resistant titanium dioxide for use in the preparation of weather-resistant ABS. The preparation method includes the following steps: S11. Grind the ABS resin at a speed of 200 rpm for 5 hours. The grinding balls are zirconia balls with a ball-to-material ratio of 13:1. Pass the mixture through a 250-mesh sieve and dry it at 65°C for later use. S12. Add 100kg of ABS resin, 4kg of weather-resistant titanium dioxide for ABS plastic, 0.4kg of UV-9 ultraviolet absorber, and 1kg of antioxidant prepared by mixing antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1 into a high-speed mixer and mix at 400rpm for 40min. Then add 1kg of polysiloxane and stir at 1000rpm for 30min to obtain a mixed powder. S13. Add the mixed powder to a twin-screw extruder, heat to 210°C, melt and extrude, granulate, and cool to obtain weather-resistant ABS.

[0029] Comparative Example 1 differs from Example 1 in that in step S2, the temperature is directly raised to 900°C and calcined for 4 hours.

[0030] Comparative Example 2 differs from Example 1 in that the step of S5, which involves the organic coating of A-151, is omitted.

[0031] Comparative Example 3 differs from Example 1 in that no polysiloxane is added to the weather-resistant ABS.

[0032] Performance testing The titanium dioxide prepared in Example 1 was subjected to technical index tests. Its whiteness was measured using an integrating sphere whiteness meter, the L and B values ​​were measured using a spectrophotometer, the titanium dioxide content was measured using aluminum reduction-cerium sulfate titration, the iron oxide content was measured using flame atomic absorption spectrometry, and the average particle size was measured using laser diffraction. The test results are shown in Table 1 below: Table 1 Basic Properties of Titanium Dioxide As shown in Table 1, the titanium dioxide prepared in Example 1 has a titanium dioxide content of 98.5 wt%, an iron oxide content of 0.0036 wt%, an average particle size of 0.32 μm, a whiteness of 98.3, an L value of 98.7, and a B value of 0.3. This indicates that the titanium dioxide prepared by this invention has high titanium dioxide purity and low iron ion impurities, thus its whiteness is greater than 98 and its L value is greater than 98.5, ensuring that the titanium dioxide presents a bright white color and will not be affected by the yellowing or graying of the titanium dioxide itself. The average particle size of 0.32 μm helps to disperse evenly in the resin and avoid agglomeration, further demonstrating that the titanium dioxide prepared by this invention has excellent anti-yellowing weather resistance and stability when applied to ABS resin.

[0033] The notched impact strength of the weather-resistant ABS prepared in each example and comparative example was measured according to GB / T 1043.1-2008 "Determination of impact properties of simply supported plastic beams - Part 1: Non-instrumental impact test". The tensile strength of the weather-resistant ABS prepared in each example and comparative example was measured according to GB / T 1040.2-2022 "Determination of tensile properties of plastics - Part 2: Test conditions for molded and extruded plastics".

[0034] The weather-resistant ABS prepared in each embodiment and comparative example were subjected to UVA-340 ultraviolet light irradiation aging at an irradiance of 0.68 W / (m²). 2 The relative humidity was controlled at 50%, and the ABS was irradiated at a blackboard temperature of 60℃ for 6 hours and condensed for 4 hours as one cycle. After 50 cycles of aging, the impact strength and tensile strength of the weather-resistant ABS were measured, and the surface color was observed to see if it changed.

[0035] The test results are shown in Table 2 below: Table 2 Performance Tests of Weather-Resistant ABS As shown in Table 2, the notched impact strength of the weather-resistant ABS resins prepared in Examples 1-3 is 37.8-38 kJ / m. 2 The tensile strength is 35.1~35.3 MPa, and the notched impact strength after aging is 37~37.2 kJ / m. 2The tensile strength is 32.5~32.8MPa, and the color remains unchanged, indicating that the titanium dioxide prepared by this invention has virtually no effect on the impact strength and tensile strength of ABS resin when applied to ABS resin, and can slow down the degradation of the mechanical properties of ABS resin after UV aging, further demonstrating that the titanium dioxide prepared by this invention can improve the weather resistance of ABS.

[0036] 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.

[0037] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing weather-resistant titanium dioxide for ABS plastic, characterized in that, Includes the following steps: S1. Acid hydrolysis: Using ilmenite as raw material, ilmenite is added to a ball mill and ball milled to obtain ilmenite powder. The ilmenite powder is added to sulfuric acid for acid hydrolysis, iron powder is added for reduction, polyacrylamide precipitant is added to settle impurities, filtered, ferrous sulfate is removed by low-temperature crystallization, and concentrated to obtain crude titanium sulfate solution. S2. Add crude titanium sulfate solution to constant temperature hot water, heat up and mature, filter and collect solid to obtain crude metatitanic acid, wash crude metatitanic acid with water, add salt treatment agent, filter by pressure to obtain filter cake, calcine filter cake, cool and grind to obtain crude titanium dioxide. S3. Pretreatment: Add crude titanium dioxide to a pulping tank, add deionized water and dispersant, pulp, sieve, and obtain slurry; S4. Inorganic coating: Sodium aluminate is added to the slurry, sulfuric acid is added dropwise to adjust the pH, the temperature is raised and aged, the solid is collected by filtration and then added to deionized water to obtain a modified slurry, sodium silicate is added dropwise, sodium hydroxide is added dropwise to adjust the pH, the temperature is raised and modified, the solid is collected by filtration, washed and dried to obtain inorganic coated titanium dioxide. S5. Organic coating: Add A-151 silane coupling agent to deionized water, add inorganic coated titanium dioxide, heat to modify, filter to collect solid, wash, and dry and pulverize by airflow to obtain weather-resistant titanium dioxide for ABS plastic.

2. The method for preparing weather-resistant titanium dioxide for ABS plastic according to claim 1, characterized in that, The chemical composition of ilmenite in S1 is as follows: titanium dioxide 50-54%, ferrous oxide 33-36%, iron oxide 5-6%, silicon dioxide 4-5%, aluminum oxide 1.5-2%, calcium oxide 0.6-0.8%, magnesium oxide 1.3-1.6%, sulfur 0.05-0.08%, and phosphorus 0.01-0.03%. The ball milling of ilmenite powder to a 200-325 mesh sieve has a passing rate of more than 90%. The mass ratio of ilmenite powder to sulfuric acid is 1:1.3-1.

5. Acidification is carried out at 150-180℃ for 1-3 hours. During acidification, the sulfuric acid concentration is maintained between 85-98 wt%. The amount of iron powder used is 2-3% of the mass of ilmenite. Reduction continues until the color of the titanium solution changes from dark brown to reddish-purple. The amount of polyacrylamide flocculant added is 5-10% of the mass of ilmenite. Crystallization is carried out at 10-20℃. The titanium content of the crude titanium sulfate solution is 200-220 g / L.

3. The method for preparing weather-resistant titanium dioxide for ABS plastic according to claim 1, characterized in that, The volume ratio of crude titanium sulfate solution to constant-temperature hot water in S2 is 20~23:

100. It is added dropwise to constant-temperature hot water at 95~97℃, and then heated to 99~102℃ under a slight boiling state for 30~50 minutes. A sample is dropped into deionized water to check whether it turns white and gray spots appear. The temperature is then raised to 102~105℃ for 2~4 hours. The salt treatment agent is prepared by mixing phosphoric acid, zinc oxide, potassium carbonate and aluminum sulfate in a mass ratio of 2:3~5:2:

1. The amount of salt treatment agent added is 0.8~1.2% of the mass of crude metatitanic acid. The mixture is calcined at 400~500℃ for 0.5~1 hours, then calcined at 700~800℃ for 1~2 hours, and finally heated to 900~950℃ and held for 10~30 minutes. The mixture is then ground until the passing rate of a 300-mesh sieve is greater than 90%.

4. The method for preparing weather-resistant titanium dioxide for ABS plastic according to claim 1, characterized in that, The dispersing agent in S3 is any one or a combination of carboxymethyl cellulose, monoisopropanolamine, and polycarboxylate dispersant. The amount of dispersing agent added is 0.1-1% of the mass of crude titanium dioxide. The mixture is pulped at a speed of 1500-2500 rpm for 1-2 hours and then passed through a 400-500 mesh sieve to obtain a slurry with a titanium content of 300-350 g / L.

5. The method for preparing weather-resistant titanium dioxide for ABS plastic according to claim 1, characterized in that, In step S4, the amount of sodium aluminate added is 0.5-2% of the slurry mass, sulfuric acid is added dropwise to adjust the pH to 4.5-5.5, the temperature is raised to 70-80℃ and aged for 1-2 hours, the titanium content of the modified slurry is 300-350 g / L, the amount of sodium silicate added is 5-10% of the modified slurry mass, sodium hydroxide is added dropwise to adjust the pH to 8.5-9.5, the modification is carried out at 50-60℃ for 1-2 hours, washed with deionized water, and dried at 50-60℃.

6. The method for preparing weather-resistant titanium dioxide for ABS plastic according to claim 1, characterized in that, The mass ratio of A-151 silane coupling agent, deionized water, and inorganic coated titanium dioxide in S5 is 4~6:100:30~35. The reaction is carried out at 80~90℃ for 1~2 hours, washed with deionized water, and dried and pulverized with an air flow rate of 15~25m / s. The inlet air temperature is 180~200℃ and the outlet air temperature is 110~120℃.

7. The weather-resistant titanium dioxide for ABS plastic prepared by the method according to any one of claims 1-6, characterized in that, It is used to prepare weather-resistant ABS, and the preparation method includes the following steps: S11. Grind the ABS resin, sieve it, dry it, and set it aside. S12. Add ABS resin, ABS plastic weather-resistant titanium dioxide, ultraviolet absorber, and antioxidant to a high-speed mixer and stir to mix. Then add polysiloxane and stir to obtain a mixed powder. S13. The mixed powder is added to a twin-screw extruder for melt extrusion, pelletized, and cooled to obtain weather-resistant ABS.

8. The weather-resistant titanium dioxide for ABS plastic according to claim 7, characterized in that, In step S11, the material is ball-milled at 100-300 rpm for 4-6 hours using zirconia balls at a ball-to-material ratio of 10-15:

1. The material is then passed through a 200-300 mesh sieve and dried at 60-70°C. In step S12, the mass ratio of ABS resin, weather-resistant titanium dioxide for ABS plastics, ultraviolet absorber, antioxidant, and polysiloxane is 100:3-6:0.3-0.5:0.5-1.5:0.5-2, at 300-500 rpm. Mix at a speed of pm for 30-50 minutes, add polysiloxane and stir at a speed of 1000-2000 rpm for 20-40 minutes. The ultraviolet absorber is any one or a combination of UV-9 ultraviolet absorber, UV-531 ultraviolet absorber, and UV-328 ultraviolet absorber. The antioxidant is prepared by mixing antioxidant 1010 and antioxidant 168 in a mass ratio of 1:

1. The temperature in S13 is raised to 200-220℃ for melt extrusion.

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