Preparation method of glass fiber reinforced modified plastic titanium dioxide pigment

Abstract

The invention relates to a preparation method of a glass fiber reinforced modified plastic titanium dioxide pigment. The method comprises the following steps: producing a rutile type titanium dioxide primary product by adopting a chlorination process, and pulping to prepare slurry; adjusting the pH value by using inorganic acid or alkali, adding a silane coupling agent for curing within a certain time, adding high-molecular siloxane for curing, and curing the cured slurry to form a layer of uniform and transparent siloxane elastomer on the surface of titanium dioxide; and adding a silane coupling agent through steam powder to finally form the product. The titanium dioxide pigment prepared by the method not only has excellent covering power, whiteness, weather resistance and the like of titanium dioxide, but also has the characteristics of low hardness and low plastic product processing difficulty of zinc sulfide, and is suitable for being used in products with high weather resistance requirements of glass fiber reinforced modified plastic outdoor systems.

Description

Technical Field

[0001] This invention relates to a method for preparing glass fiber reinforced modified plastic titanium dioxide pigment. Background Technology

[0002] Titanium dioxide, as an important inorganic chemical product, has the characteristics of high refractive index, excellent hiding power and tinting power, good heat resistance and strong UV resistance. It is widely used in plastics, papermaking, coatings, cosmetics, food and other fields, and is an indispensable key raw material in many industrial fields.

[0003] Plastics are polymeric compounds formed by polymerization of monomers through addition or condensation reactions. Their main component is resin, and they are ductile synthetic polymers. Among plastic modifications, glass fiber reinforcement is the most widespread. Glass fiber reinforced plastics are composite plastics using glass fiber reinforced unsaturated polyester, epoxy resin, and phenolic resin as matrix materials. Glass fiber reinforced plastics have a low density, weighing only about 20% to 25% of carbon steel, but their tensile strength is close to or even exceeds that of carbon steel. Due to their high strength, good performance, and energy-saving advantages, they are widely used in industrial sectors and high-tech fields such as automobiles, machinery, electrical appliances, ships, 5G base stations, construction, and aerospace.

[0004] Currently, titanium dioxide, known for its strong coloring power and weather resistance, cannot be used in white glass fiber reinforced modified plastics. This is because rutile titanium dioxide has a Mohs hardness of around 7, while glass fiber has a hardness of around 5.5. During the plastic extrusion and injection molding process, the high shear force of the titanium dioxide wears down or directly cuts the glass fiber, resulting in a significant reduction in the mechanical properties of the glass fiber modified plastic and the loss of its original excellent properties. Furthermore, titanium dioxide used in plastics typically requires inorganic and organic surface modifiers to eliminate photoactivation points on the titanium dioxide surface. Surface coatings with silicon or aluminum are commonly used. Titanium dioxide crystals often contain defects such as oxygen vacancies and lattice distortions, resulting in an incomplete crystal structure and leaving oxygen vacancies on the surface. These oxygen vacancies can adsorb water molecules, forming hydroxyl groups (-OH-). In glass fiber reinforced modified plastics, the glass fibers undergo acid washing and other treatments to remove polar groups. However, the addition of titanium dioxide causes more polar groups (-OH-) to crystallize on the surface of the titanium dioxide and less on the glass fibers, resulting in a significant reduction in the adhesion between the glass fibers and the resin. Therefore, ZnS white pigment, which has slightly lower whiteness, hiding power, and weather resistance, is used in white glass fiber reinforced modified plastics. However, in high-end fields, especially aerospace where material stability is crucial, and in 5G base stations and rapidly developing automotive parts where whiteness and weather resistance are extremely important, ZnS white pigment cannot meet these application requirements. CN 202111509748.0 discloses "a preparation method of zinc sulfide modified titanium dioxide pigment", and CN202211312048.7 discloses "a preparation method of titanium dioxide pigment for glass fiber reinforced modified plastics". Both methods use inorganic zinc sulfide for surface modification. However, the whiteness and weather resistance of zinc sulfide itself are slightly inferior to those of rutile titanium dioxide. In order to shield the photoactivation points of titanium dioxide, a large amount of inorganic film needs to be coated. Therefore, it is impossible to bring out the best characteristics of high whiteness, high hiding power and best weather resistance of titanium dioxide in glass fiber reinforced modified plastics. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for preparing titanium dioxide pigment for glass fiber reinforced modified plastics. The titanium dioxide pigment for glass fiber reinforced modified plastics prepared by this method has the characteristics of high whiteness, high hiding power, high tinting strength, low hardness, and ultra-high weather resistance. Moreover, the glass fiber reinforced modified plastic products prepared by this method have excellent whiteness and ultra-high weather resistance, especially with excellent stability in the mechanical properties of the material.

[0006] The technical solution of this invention is: A method for preparing glass fiber reinforced modified plastic titanium dioxide pigment, characterized by: The specific steps are as follows: (1) Using rutile titanium dioxide primary product obtained by chloride process, titanium dioxide slurry is prepared by slurrying with deionized water; (2) Heat the titanium dioxide slurry to 40℃~60℃ and maintain this temperature throughout the coating process; (3) Adjust the pH of the slurry to 6.5-7.5 with inorganic acid solution or inorganic alkali solution; add silane coupling agent at one time, wherein the silane coupling agent is at least one of methyltrichlorosilane or phenyltrichlorosilane, and the amount of silane coupling agent added accounts for 1%-2% of the mass of TiO2, and mature for 60 min-120 min; (4) Add the slurry after maturation in step (3) to a high molecular weight siloxane liquid within 10 min to 30 min. The high molecular weight siloxane liquid is dihydroxy polydimethylsiloxane. The amount of high molecular weight siloxane liquid added accounts for 5% to 10% of the mass of TiO2. Mature for 60 min to 120 min. (5) After drying and curing the slurry after maturation in step (4), it is subjected to steam powder treatment, and a silane coupling agent is added during the steam powder process. The silane coupling agent is at least one of methyltrichlorosilane and phenyltrichlorosilane. The amount of silane coupling agent added accounts for 1% to 2% of the mass of TiO2, and glass fiber reinforced modified plastic titanium dioxide pigment is obtained.

[0007] Furthermore, the viscosity of the dihydroxy polydimethylsiloxane is ≥50000mm² / s.

[0008] Furthermore, in step (5), the drying and curing temperature is 100℃~200℃, and the drying and curing time is 8h.

[0009] Furthermore, the mass concentration of the titanium dioxide slurry is 20% to 30%.

[0010] Further, in step (3), the inorganic alkaline solution is at least one of sodium hydroxide solution and potassium hydroxide solution, and the inorganic acid solution is at least one of hydrochloric acid solution, sulfuric acid solution, nitric acid solution, and phosphoric acid solution.

[0011] Furthermore, the mass concentration of the inorganic alkaline solution is 10% to 20%, and the mass concentration of the inorganic acid solution is 10% to 20%.

[0012] Compared with the prior art, the beneficial effects of the present invention are: (1) Using rutile titanium dioxide oxide primary product as raw material, it has the characteristics of high spherical ratio, uniform particle size distribution, good weather resistance and strong covering power.

[0013] (2) Using silane coupling agent monomers (methyltrichlorosilane, phenyltrichlorosilane) as surface modification precursors, the chlorine atoms of methyltrichlorosilane and phenyltrichlorosilane are replaced by hydroxyl functional groups (-OH-) on the surface of titanium dioxide, thereby achieving adhesion between the silane coupling agent and the substrate, while shielding the heterogeneous nucleation effect of hydroxyl functional groups (-OH-) in glass fiber modified resin, preventing titanium dioxide and glass fiber from competing for bonding force with the resin substrate; another part of the chlorine atoms can undergo condensation reaction with the hydroxyl groups of hydroxyl polydimethylsiloxane to form a mixed polymer with a linear structure.

[0014] (3) After condensation of silane coupling agent monomers (methyltrichlorosilane, phenyltrichlorosilane) with dihydroxy polydimethylsiloxane and curing at a specific temperature, an elastomer with a transmittance of ≥95% is formed. This fully utilizes the high whiteness and strong hiding power of titanium dioxide. The elastomer formed after curing has high tensile strength and excellent material properties. Dihydroxy polydimethylsiloxane elastomer has excellent thermal stability after curing, with high temperature resistance up to 300℃ and strong UV resistance. It also has good temperature and humidity stability. Titanium dioxide modified with hydroxy polydimethylsiloxane elastomer is particularly suitable for applications in aerospace and 5G base stations where outdoor weather resistance is extremely important.

[0015] (3) The silane coupling agent monomers methyltrichlorosilane and phenyltrichlorosilane coated in the gas powder process can effectively improve the compatibility and dispersibility of titanium dioxide products in glass fiber reinforced modified plastics, improve the adhesion between glass fiber and resin, and enhance the mechanical properties of glass fiber reinforced composites. Such products can be applied to higher-end glass fiber reinforced modified plastic products, filling a gap in this field.

[0016] In summary, the titanium dioxide pigment prepared by this invention has high whiteness, ultra-high weather resistance and material properties, and can be widely used in the field of plastics such as glass fiber reinforced modified plastics, which have particularly high requirements for stable mechanical properties and weather resistance. Detailed Implementation

[0017] The present invention will be further described below with reference to specific embodiments. However, the application scope of the present invention is not limited to the embodiments. Various substitutions and modifications made without departing from the technical concept of the present invention should be within the scope of the present invention.

[0018] Example 1 1.1 Using rutile titanium dioxide primary product obtained by chloride process, slurry with deionized water was prepared to form titanium dioxide slurry with a mass concentration of 20%, and the temperature was raised to 40℃ and maintained throughout the coating process; 1.2 Adjust the pH of the slurry to 6.5 with a 10% hydrochloric acid solution or a 20% sodium hydroxide solution; add 1% methyltrichlorosilane by mass of TiO2 in one step and let it mature for 60 minutes. 1.3 Add 5% (by mass) of dihydroxy polydimethylsiloxane (HO-Si(CH3)2-O[Si(CH3)2-O]) to the slurry after maturation in step 1.2 within 10 min. n -Si(CH3)2-OH), with a viscosity of 50000 mm² / s, after aging for 80 min, it was dried and cured at 100℃ for 8 h; 1.4 The material dried in step 1.3 is subjected to steam powder treatment. During the steam powder treatment, methyltrichlorosilane accounting for 1% of the mass of TiO2 is added to obtain a special titanium dioxide pigment for glass fiber reinforced modified plastics.

[0019] Example 2 1.1 Using rutile titanium dioxide primary product obtained by chloride process, slurry was prepared with deionized water to form titanium dioxide slurry with a mass concentration of 30%, heated to 60°C, and maintained at this temperature throughout the coating process; 1.2 Adjust the pH of the slurry to 7.5 with a 20% hydrochloric acid solution or a 10% sodium hydroxide solution; add 2% phenyltrichlorosilane by mass of TiO2 in one step and let it mature for 120 min. 1.3 Add 10% (by mass) of dihydroxy polydimethylsiloxane (HO-Si(CH3)2-O[Si(CH3)2-O]) to the slurry matured in step 1.2 within 30 min. n -Si(CH3)2-OH), viscosity 50000 mm² / s, aged for 80 min, and then dried and cured at 200℃ for 8 h; 1.4 The material dried in step 1.3 is subjected to steam powder treatment. During the steam powder treatment, phenyltrichlorosilane accounting for 2% of the mass of TiO2 is added to obtain a special titanium dioxide pigment for glass fiber reinforced modified plastics.

[0020] Example 3 1.1 Using rutile titanium dioxide primary product obtained by chloride process, slurry was prepared by deionized water to form titanium dioxide slurry with a mass concentration of 25%, heated to 50°C, and maintained at this temperature throughout the coating process; 1.2 Adjust the pH of the slurry to 7.0 with a 15% hydrochloric acid solution or a 15% sodium hydroxide solution; add 1.5% methyltrichlorosilane by mass of TiO2 at once, and let it mature for 90 min; 1.3 Add 7.5% (by mass) of dihydroxy polydimethylsiloxane (HO-Si(CH3)2-O[Si(CH3)2-O]) to the slurry matured in step 1.2 within 20 min. n -Si(CH3)2-OH), viscosity 50000 mm² / s, aged for 80 min, and then dried and cured at 150℃ for 8 h; 1.4 The material dried in step 1.3 is subjected to steam powder treatment. During the steam powder treatment, 1.5% of phenyltrichlorosilane by mass of TiO2 is added to obtain a special titanium dioxide pigment for glass fiber reinforced modified plastics.

[0021] Comparative Example 1 Same as Example 3, except that step 1.2, in which methyltrichlorosilane accounting for 1.5% of the mass of TiO2, is added at once, is omitted.

[0022] 1.1 Using rutile titanium dioxide primary product obtained by chloride process, slurry was prepared by deionized water to form titanium dioxide slurry with a mass concentration of 25%, heated to 50°C, and maintained at this temperature throughout the coating process; 1.2 Adjust the pH of the slurry to 7.0 with a 15% hydrochloric acid solution or a 15% sodium hydroxide solution, and let it mature for 90 minutes; 1.3 Add 7.5% (by mass) of dihydroxy polydimethylsiloxane (HO-Si(CH3)2-O[Si(CH3)2-O]) to the slurry matured in step 1.2 within 20 min. n -Si(CH3)2-OH), viscosity 50000 mm² / s, aged for 80 min, and then dried and cured at 150℃ for 8 h; 1.4 The material dried in step 1.3 is subjected to steam powder treatment. During the steam powder treatment, 1.5% of phenyltrichlorosilane by mass of TiO2 is added to obtain titanium dioxide pigment.

[0023] Comparative Example 2 Same as Example 3, except that step 1.3, in which 7.5% of the mass of TiO2 is added within 20 minutes, is omitted.

[0024] 1.1 Using rutile titanium dioxide primary product obtained by chloride process, slurry was prepared by deionized water to form titanium dioxide slurry with a mass concentration of 25%, heated to 50°C, and maintained at this temperature throughout the coating process; 1.2 Adjust the pH of the slurry to 7.0 with a 15% hydrochloric acid solution or a 15% sodium hydroxide solution; add 1.5% methyltrichlorosilane by mass of TiO2 at once, and let it mature for 90 min; 1.3 The slurry matured in step 1.2 is dried and cured at 150℃ for 8 hours; 1.4 The material dried in step 1.3 is subjected to steam powder treatment. During the steam powder treatment, 1.5% of phenyltrichlorosilane by mass of TiO2 is added to obtain titanium dioxide pigment.

[0025] Comparative Example 3 Same as Example 3, except that step 1.4, in which phenyltrichlorosilane accounting for 1.5% of the mass of TiO2 is added during the gasification process, is omitted.

[0026] 1.1 Using rutile titanium dioxide primary product obtained by chloride process, slurry was prepared by deionized water to form titanium dioxide slurry with a mass concentration of 25%, heated to 50°C, and maintained at this temperature throughout the coating process; 1.2 Adjust the pH of the slurry to 7.0 with a 15% hydrochloric acid solution or a 15% sodium hydroxide solution; add 1.5% methyltrichlorosilane by mass of TiO2 at once, and let it mature for 90 min; 1.3 Add 7.5% (by mass) of dihydroxy polydimethylsiloxane (HO-Si(CH3)2-O[Si(CH3)2-O]) to the slurry matured in step 1.2 within 20 min. n -Si(CH3)2-OH), viscosity 50000 mm² / s, aged for 80 min, and then dried and cured at 150℃ for 8 h; 1.4 The material dried in step 1.3 is subjected to steam powder treatment to obtain titanium dioxide pigment.

[0027] Comparative Example 4 Same as Example 3: In step 1.2, 1.5% silane coupling agent A151 (based on the weight of vinyltriethoxysilane in TiO2) is added all at once. In step 1.4, 1.5% silane coupling agent A151 (based on the weight of vinyltriethoxysilane in TiO2) is added during the gasification process.

[0028] 1.1 Using rutile titanium dioxide primary product obtained by chloride process, slurry was prepared by deionized water to form titanium dioxide slurry with a mass concentration of 25%, heated to 50°C, and maintained at this temperature throughout the coating process; 1.2 Adjust the pH of the slurry to 7.0 with a 15% hydrochloric acid solution or a 15% sodium hydroxide solution; add 1.5% of the TiO2 mass of silane coupling agent A151 at once, and let it mature for 90 min; 1.3 Add 7.5% (by mass) of dihydroxy polydimethylsiloxane (HO-Si(CH3)2-O[Si(CH3)2-O]) to the slurry matured in step 1.2 within 20 min. n -Si(CH3)2-OH), viscosity 50000 mm² / s, aged for 80 min, and then dried and cured at 150℃ for 8 h; 1.4 The material dried in step 1.3 is subjected to steam powder treatment. During the steam powder treatment, 1.5% of the mass of TiO2 silane coupling agent A151 is added to obtain titanium dioxide pigment.

[0029] Comparative Example 5 Same as Example 3: In step 1.2, 1.5% silane coupling agent KH570 (based on the weight of γ-methacryloxypropyltrimethoxysilane in TiO2) is added at once; in step 1.4, 1.5% silane coupling agent KH570 (based on the weight of γ-methacryloxypropyltrimethoxysilane in TiO2) is added during the gasification process.

[0030] 1.1 Using rutile titanium dioxide primary product obtained by chloride process, slurry was prepared by deionized water to form titanium dioxide slurry with a mass concentration of 25%, heated to 50°C, and maintained at this temperature throughout the coating process; 1.2 Adjust the pH of the slurry to 7.0 with a 15% hydrochloric acid solution or a 15% sodium hydroxide solution; add 1.5% of the TiO2 mass of silane coupling agent KH570 at once, and let it mature for 90 minutes; 1.3 Add 7.5% (by mass) of dihydroxy polydimethylsiloxane (HO-Si(CH3)2-O[Si(CH3)2-O]) to the slurry matured in step 1.2 within 20 min. n -Si(CH3)2-OH), viscosity 50000 mm² / s, aged for 80 min, and then dried and cured at 150℃ for 8 h; 1.4 The material dried in step 1.3 is subjected to steam powder treatment. During the steam powder treatment, 1.5% of the mass of TiO2 silane coupling agent KH570 is added to obtain titanium dioxide pigment.

[0031] Comparative Example 6 Same as Example 3: Step 1.2: Adding 1.5% methyltrichlorosilane at once (the amount added is based on the weight of methyltrichlorosilane to TiO2); Step 1.4: Adding 1.5% phenyltrichlorosilane during the gasification process (the amount added is based on the weight of phenyltrichlorosilane to TiO2).

[0032] 1.1 Using rutile titanium dioxide primary product obtained by chloride process, slurry was prepared by deionized water to form titanium dioxide slurry with a mass concentration of 25%, heated to 50°C, and maintained at this temperature throughout the coating process; 1.2 Adjust the pH of the slurry to 7.0 with a 15% hydrochloric acid solution or a 15% sodium hydroxide solution, and let it mature for 90 minutes; 1.3 Add 7.5% (by mass) of dihydroxy polydimethylsiloxane (HO-Si(CH3)2-O[Si(CH3)2-O]) to the slurry matured in step 1.2 within 20 min. n -Si(CH3)2-OH), viscosity 50000 mm² / s, aged for 80 min, and then dried and cured at 150℃ for 8 h; 1.4 The material dried in step 1.3 is subjected to steam powder treatment to obtain titanium dioxide pigment.

[0033] Comparative Example 7 Same as Example 3, except that in step 1.2: the pH value of the slurry is adjusted to 5.5 with hydrochloric acid solution or sodium hydroxide solution.

[0034] 1.1 Using rutile titanium dioxide primary product obtained by chloride process, slurry was prepared by deionized water to form titanium dioxide slurry with a mass concentration of 25%, heated to 50°C, and maintained at this temperature throughout the coating process; 1.2 Adjust the pH of the slurry to 5.5 with a 15% hydrochloric acid solution or a 15% sodium hydroxide solution; add 1.5% methyltrichlorosilane by mass of TiO2 at once, and let it mature for 90 min; 1.3 Add 7.5% (by mass) of dihydroxy polydimethylsiloxane (HO-Si(CH3)2-O[Si(CH3)2-O]) to the slurry matured in step 1.2 within 20 min. n -Si(CH3)2-OH), viscosity 50000 mm² / s, aged for 80 min, and then dried and cured at 150℃ for 8 h; 1.4 The material dried in step 1.3 is subjected to steam powder treatment. During the steam powder treatment, 1.5% of phenyltrichlorosilane by mass of TiO2 is added to obtain titanium dioxide pigment.

[0035] Comparative Example 8 Same as Example 3, except that in step 1.2: the pH value of the slurry is adjusted to 8.5 with hydrochloric acid solution or sodium hydroxide solution.

[0036] 1.1 Using rutile titanium dioxide primary product obtained by chloride process, slurry was prepared by deionized water to form titanium dioxide slurry with a mass concentration of 25%, heated to 50°C, and maintained at this temperature throughout the coating process; 1.2 Adjust the pH of the slurry to 8.5 with a 15% hydrochloric acid solution or a 15% sodium hydroxide solution; add 1.5% methyltrichlorosilane by mass of TiO2 at once, and let it mature for 90 min; 1.3 Add 7.5% (by mass) of dihydroxy polydimethylsiloxane (HO-Si(CH3)2-O[Si(CH3)2-O]) to the slurry matured in step 1.2 within 20 min. n -Si(CH3)2-OH), viscosity 50000 mm² / s, aged for 80 min, and then dried and cured at 150℃ for 8 h; 1.4 The material dried in step 1.3 is subjected to steam powder treatment. During the steam powder treatment, 1.5% of phenyltrichlorosilane by mass of TiO2 is added to obtain titanium dioxide pigment.

[0037] Comparative Example 9 Same as Example 3, except that in step 1.2: 0.5% methyltrichlorosilane is added at once (the amount added is based on the weight of methyltrichlorosilane as a percentage of TiO2).

[0038] 1.1 Using rutile titanium dioxide primary product obtained by chloride process, slurry was prepared by deionized water to form titanium dioxide slurry with a mass concentration of 25%, heated to 50°C, and maintained at this temperature throughout the coating process; 1.2 Adjust the pH of the slurry to 7.0 with a 15% hydrochloric acid solution or a 15% sodium hydroxide solution; add 0.5% methyltrichlorosilane by mass of TiO2 in one step and let it mature for 90 minutes. 1.3 Add 7.5% (by mass) of dihydroxy polydimethylsiloxane (HO-Si(CH3)2-O[Si(CH3)2-O]) to the slurry matured in step 1.2 within 20 min. n -Si(CH3)2-OH), viscosity 50000 mm² / s, aged for 80 min, and then dried and cured at 150℃ for 8 h; 1.4 The material dried in step 1.3 is subjected to steam powder treatment. During the steam powder treatment, 1.5% of phenyltrichlorosilane by mass of TiO2 is added to obtain titanium dioxide pigment.

[0039] Comparative Example 10 Same as Example 3, except that in step 1.3: 2% dihydroxy polydimethylsiloxane (based on the weight of dihydroxy polydimethylsiloxane as TiO2) is added within 20 min.

[0040] 1.1 Using rutile titanium dioxide primary product obtained by chloride process, slurry was prepared by deionized water to form titanium dioxide slurry with a mass concentration of 25%, heated to 50°C, and maintained at this temperature throughout the coating process; 1.2 Adjust the pH of the slurry to 7.0 with a 15% hydrochloric acid solution or a 15% sodium hydroxide solution; add 1.5% methyltrichlorosilane by mass of TiO2 at once, and let it mature for 90 min; 1.3 Add 2% (by mass) of dihydroxy polydimethylsiloxane (HO-Si(CH3)2-O[Si(CH3)2-O]) to the slurry matured in step 1.2 within 20 min. n -Si(CH3)2-OH), viscosity 50000 mm² / s, aged for 80 min, and then dried and cured at 150℃ for 8 h; 1.4 The material dried in step 1.3 is subjected to steam powder treatment. During the steam powder treatment, 1.5% of phenyltrichlorosilane by mass of TiO2 is added to obtain titanium dioxide pigment.

[0041] Comparative Example 11 Same as Example 3, except that in step 1.4: 0.5% phenyltrichlorosilane is added during the gasification process (the amount added is based on the weight of phenyltrichlorosilane as a percentage of TiO2).

[0042] 1.1 Using rutile titanium dioxide primary product obtained by chloride process, slurry was prepared by deionized water to form titanium dioxide slurry with a mass concentration of 25%, heated to 50°C, and maintained at this temperature throughout the coating process; 1.2 Adjust the pH of the slurry to 7.0 with a 15% hydrochloric acid solution or a 15% sodium hydroxide solution; add 1.5% methyltrichlorosilane by mass of TiO2 at once, and let it mature for 90 min; 1.3 Add 7.5% (by mass) of dihydroxy polydimethylsiloxane (HO-Si(CH3)2-O[Si(CH3)2-O]) to the slurry matured in step 1.2 within 20 min. n -Si(CH3)2-OH), viscosity 50000 mm² / s, aged for 80 min, and then dried and cured at 150℃ for 8 h; 1.4 The material dried in step 1.3 is subjected to steam powder treatment. During the steam powder treatment, 0.5% of phenyltrichlorosilane by mass of TiO2 is added to obtain titanium dioxide pigment.

[0043] The whiteness (L*) of the titanium dioxide powder products prepared in Examples 1 to 3 and Comparative Examples 1 to 10 is shown in Table 1. The impact resistance test results were obtained by adding the above products to a glass fiber reinforced modified nylon resin system at a 2% addition ratio, and then injection molding notched impact test specimens. The initial whiteness L*, initial b*, and weather resistance index ΔE* were obtained by adding the above products to a glass fiber reinforced modified nylon resin system at a 2% addition ratio, and then injection molding white boards and undergoing 720 hours of xenon lamp irradiation.

[0044] Table 1 shows the relevant indicators and application indicators of the products in the examples. Powder L* <![CDATA[Izod impact strength kJ / m 2 > Initial L* (whiteness) △E* Example 1 98.29 13.26 93.03 0.65 Example 2 98.26 13.57 92.91 0.47 Example 3 98.27 13.79 92.97 0.53 Comparative Example 1 98.21 9.65 92.99 1.02 Comparative Example 2 98.2 9.21 93.01 1.14 Comparative Example 3 98.21 11.93 93.04 0.89 Comparative Example 4 98.18 10.03 92.98 1.08 Comparative Example 5 98.19 9.91 92.87 0.97 Comparative Example 6 98.17 9.03 92.91 1.24 Comparative Example 7 98.21 11.94 93.05 0.84 Comparative Example 8 98.19 12.26 92.88 0.78 Comparative Example 9 98.21 11.91 92.89 1.06 Comparative Example 10 98.22 11.74 92.93 0.86 Comparative Example 11 98.23 12.43 93.00 0.61

[0045] Note: The weather resistance of this invention is characterized by the change of ΔE* under xenon lamp irradiation for 720 hours after injection molding into a white board.

[0046] As can be seen from the comparison of Examples 1-3 in the table above, the relevant key indicators and application indicators of the three samples are very similar; the higher the impact resistance index, the less the impact of titanium dioxide on the impact resistance; the lower the weather resistance ΔE* index, the better the curing and coating effect of dihydroxy polydimethylsiloxane.

[0047] The comparison results between Comparative Example 1 and Example 3 show that after removing the first step of coating with methyltrichlorosilane, the impact resistance of the product decreased significantly, while the weather resistance decreased slightly. The comparison results between Comparative Example 2 and Example 3 show that after removing the coating with dihydroxypolydimethylsiloxane, the impact resistance and weather resistance decreased significantly. The comparison results between Comparative Example 3 and Example 3 show that after removing the coating of phenyltrichlorosilane with gasoline powder, the impact resistance of the product decreased. The comparison results between Comparative Examples 4 and 5 and Example 3 show that changing the type of silane coupling agent significantly reduced the impact resistance. The comparison results between Comparative Example 6 and Example 3 show… The removal of the first step of coating with methyltrichlorosilane and coating with phenyltrichlorosilane using air powder significantly reduced impact resistance and weather resistance. Comparisons 7 and 8 with Example 3 showed that excessively low / high pH values ​​in the coating caused a decrease in impact resistance and weather resistance. Comparison 9 with Example 3 showed that reducing the amount of methyltrichlorosilane significantly reduced impact resistance and weather resistance. Comparison 10 with Example 3 showed that reducing the amount of hydroxyl polydimethylsiloxane reduced impact resistance. Comparison 11 with Example 3 showed that reducing the amount of phenyltrichlorosilane coated with air powder reduced impact resistance.

[0048] Therefore, it can be seen that the titanium dioxide pigment produced according to the specific preparation method of the present invention has high whiteness, ultra-high weather resistance and cantilever beam notched impact resistance, and can be widely used in the field of high-quality plastics such as glass fiber reinforced modified plastics; moreover, the production cost of titanium dioxide pigment prepared by this method is low, the manufacturing method is simple, the raw material utilization rate is high, and it is conducive to energy conservation and environmental protection.

Claims

1. A method for preparing a glass fiber reinforced modified plastic titanium dioxide pigment, characterized by the following specific steps: The specific steps are as follows: (1) using chlorination rutile titanium dioxide primary product, using deionized water to make titanium dioxide slurry; (2) heating the titanium dioxide slurry to 40-60℃, and maintaining the temperature during the entire coating process; (3) adjusting the pH value of the slurry to 6.5-7.5 with an inorganic acid solution or an inorganic base solution; adding a silane coupling agent at one time, the silane coupling agent being at least one of methyltrichlorosilane and phenyltrichlorosilane, the amount of silane coupling agent added being 1-2% of the mass of TiO2, and aging for 60-120 min; (4) adding a high molecular siloxane liquid to the aged slurry in step (3) within 10-30 min, the high molecular siloxane pure liquid being dihydroxy polydimethylsiloxane, the amount of high molecular siloxane liquid added being 5-10% of the mass of TiO2, and aging for 60-120 min; (5) after drying and solidifying the aged slurry in step (4), performing steam powder treatment, and adding a silane coupling agent during the steam powder treatment, the silane coupling agent being at least one of methyltrichlorosilane and phenyltrichlorosilane, the amount of silane coupling agent added being 1-2% of the mass of TiO2, to obtain the glass fiber reinforced modified plastic titanium dioxide pigment.

2. The method for preparing glass fiber reinforced modified plastic titanium dioxide pigment according to claim 1, characterized in that: The viscosity of the dihydroxy polydimethylsiloxane is ≥50000 mm² / s.

3. The method for preparing glass fiber reinforced modified plastic titanium dioxide pigment according to claim 1, characterized in that: In step (5), the drying and solidifying temperature is 100-200℃, and the drying and solidifying time is 8 h.

4. The method for preparing glass fiber reinforced modified plastic titanium dioxide pigment according to claim 1, characterized in that: The mass concentration of the titanium dioxide slurry is 20-30%.

5. The method for preparing glass fiber reinforced modified plastic titanium dioxide pigment according to claim 1, characterized in that: In step (3), the inorganic base solution is at least one of a sodium hydroxide solution and a potassium hydroxide solution, and the inorganic acid solution is at least one of a hydrochloric acid solution, a sulfuric acid solution, a nitric acid solution, and a phosphoric acid solution.

6. The method for preparing glass fiber reinforced modified plastic titanium dioxide pigment according to claim 5, characterized in that: The mass concentration of the inorganic base solution is 10-20%, and the mass concentration of the inorganic acid solution is 10-20%.