Multilayer-coated titanium dioxide organic-inorganic hybrid particles, process for their production and use

Abstract

This invention belongs to the field of polymer nanomaterials and discloses a multilayered titanium dioxide organic-inorganic hybrid particle, its preparation method, and its application. The multilayered titanium dioxide organic-inorganic hybrid particle comprises titanium dioxide particles and, from the inside out, a silane coupling agent layer and an organic UV-blocking agent layer sequentially coated on its surface. The thickness of the silane coupling agent layer is 50-70 nm, and the thickness of the organic UV-blocking agent layer is 20-30 nm. The preparation method involves chemically bonding the organic UV-blocking agent to the silane coupling agent-coated titanium dioxide particles, thus forming the multilayered titanium dioxide organic-inorganic hybrid particle. Its application is in the preparation of fibers. The multilayered titanium dioxide organic-inorganic hybrid particle prepared using this invention exhibits high ultraviolet absorption, and the fibers and fabrics prepared using it have high blocking rates for both ultraviolet and visible light.

Description

Technical Field

[0001] This invention belongs to the field of polymer nanomaterials, and relates to a multilayer coated titanium dioxide organic-inorganic hybrid particle, its preparation method and application. Background Technology

[0002] In recent years, with the advancement of science and technology and the increasing health awareness of people, the research and development of UV-resistant functional materials has become increasingly important. Early on, organic UV shielding agents were the main UV-resistant finishing agents. Although they possess a certain degree of stability, prolonged exposure to ultraviolet light can lead to their decomposition, producing potentially harmful byproducts that can cause adverse symptoms such as allergies. Furthermore, they may be absorbed into the body through the skin, posing potential safety risks. In addition, the absorption wavelength range of organic UV shielding agents is relatively narrow, limiting their application scope.

[0003] Due to the drawbacks of organic UV shielding agents, current research has shifted towards inorganic shielding agents. Titanium dioxide particles, being an easily prepared, inexpensive, non-toxic, and biocompatible functional nanomaterial, have attracted significant attention. They not only effectively absorb and scatter ultraviolet (UV) radiation, protecting against its harmful effects, but also exhibit strong absorption of mid-wavelength UV radiation. However, the weak absorption of long-wavelength UV radiation by titanium dioxide particles limits their performance in certain specific applications.

[0004] To overcome the limitations of organic and inorganic shielding agents, existing technologies have begun to explore methods that combine the advantages of both to develop more efficient and safer UV-resistant functional materials. For example, patent CN108246216B discloses a core-shell structured organic / inorganic composite hollow porous microsphere and its preparation method. The method involves dissolving styrene, a difunctional dimethacrylate organic monomer, a photoinitiator, and an organic UV absorber in a solvent to obtain an electrospray solution. Modified titanium dioxide particles with double bonds on their surface are then added to the electrospray solution and dispersed evenly. The hollow porous microspheres, composed of cross-linked spheres, titanium dioxide particles, and an organic UV absorber, are then obtained by electrostatic spraying under visible light conditions. However, the prepared hollow porous microspheres use polystyrene microspheres as a carrier to attach titanium dioxide particles within the microspheres. The extinction effect comes solely from the titanium dioxide particles and the UV absorber themselves, without mentioning the synergistic effect between the two. Furthermore, from the perspective of titanium dioxide particles and the UV absorber alone, it is difficult to achieve high absorption efficiency for ultraviolet light.

[0005] Existing multilayer coating technologies can design specific layer structures to create synergistic effects between different layers, thereby enhancing the matting and UV resistance of titanium dioxide particles. However, current technologies primarily couple multiple functions into titanium dioxide particles through multilayer coating, such as increasing their weather resistance or antibacterial properties, rather than enhancing their UV resistance and improving their UV absorption rate through layer structure design. Summary of the Invention

[0006] The purpose of this invention is to solve the problems existing in the prior art and to provide a multilayer coated titanium dioxide organic-inorganic hybrid particle, its preparation method and application.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] Multilayer coated titanium dioxide organic-inorganic hybrid particles include titanium dioxide particles and a silane coupling agent layer and an organic UV stabilizer layer sequentially coated on their surface from the inside out;

[0009] The thickness of the silane coupling agent layer is 50-70 nm, and the thickness of the organic UV stabilizer layer is 20-30 nm.

[0010] When ultraviolet (UV) light strikes the particle surface, it first comes into contact with the organic UV-blocking agent layer. This organic agent absorbs some UV light in the 290-400 nm wavelength range. However, due to the low loading, the absorption rates for both the 290-350 nm and 350-400 nm wavelength ranges are only about 80%. The UV light penetrates the organic UV-blocking agent layer, passes through the silane coupling agent layer, and reaches the surface of the titanium dioxide particles. The titanium dioxide particles have a strong absorption capacity for the 290-350 nm wavelength range, absorbing approximately 19.8% of this wavelength. However, they only scatter the 350-400 nm wavelength range. Therefore, about 20% of the 350-400 nm wavelength UV light in the incident light is scattered on the surface of the titanium dioxide particles, re-enters the outermost organic UV-blocking agent layer, and is absorbed again. This step absorbs approximately 16% of the 350-400 nm wavelength UV light. Because the multilayer coating creates interfaces between titanium dioxide particles and the silane coupling agent layer, and between the silane coupling agent layer and the organic UV stabilizer layer, ultraviolet light is refracted and scattered at these interfaces. Approximately 4% of the 350-400 nm ultraviolet light is absorbed by the organic UV stabilizer layer during scattering and refraction, while approximately 0.2% of the 290-350 nm ultraviolet light is absorbed by the titanium dioxide particles. Therefore, in this multilayer coated titanium dioxide particle structure, the absorption rate of incident 290-400 nm ultraviolet light can approach 100%.

[0011] As a preferred technical solution:

[0012] The multi-layered titanium dioxide organic-inorganic hybrid particles described above have an ultraviolet absorption rate of over 99.9%.

[0013] The multilayer coated titanium dioxide organic-inorganic hybrid particles described above have an average particle size of 150-200 nm.

[0014] The multilayer coated titanium dioxide organic-inorganic hybrid particles described above use KH550 as the silane coupling agent and one or more of the following organic UV absorbers: benzophenone with phenolic hydroxyl groups, benzotriazole with phenolic hydroxyl groups, and triazine organic UV absorbers with phenolic hydroxyl groups.

[0015] The present invention also provides a method for preparing multilayer coated titanium dioxide organic-inorganic hybrid particles as described above, wherein an organic UV stabilizer is chemically bonded to titanium dioxide particles coated with a silane coupling agent, thereby producing multilayer coated titanium dioxide organic-inorganic hybrid particles.

[0016] As a preferred technical solution:

[0017] The method described above involves the following steps: dispersing titanium dioxide particles coated with silane coupling agent in a solvent to obtain a dispersion; adding sodium sulfite and stirring at 400-550 rpm for 0.4-1 h; adding an organic UV stabilizer and stirring at 400-550 rpm for 30-60 min; heating to the solvent reflux temperature and maintaining the temperature for 24 h; and then post-processing (washing with deionized water more than 3 times and pulverizing with a pulverizer) to obtain multi-layered coated titanium dioxide organic-inorganic hybrid particles. The solvent is a good solvent for the organic UV stabilizer. During the reaction, the phenolic hydroxyl groups of the organic UV stabilizer react with sodium sulfite to form sodium salts, increasing the polarity of the phenolic hydroxyl groups. The phenolic hydroxyl groups of the organic UV stabilizer readily undergo esterification reactions with the carboxyl groups in the silane coupling agent.

[0018] As described above, the solvent is an aqueous solution of ethanol with a concentration of 70-80% v / v, an aqueous solution of acetone with a concentration of 70-80% v / v, or water; the concentration of the dispersion is 8-10 mg / mL; the amount of sodium sulfite added per milliliter of solvent is 0.1-1 mg; and the mass ratio of the organic UV stabilizer to the titanium dioxide particles coated with the silane coupling agent is 1-3:100.

[0019] The preparation steps of silane coupling agent-coated titanium dioxide particles are as follows: (As described above)

[0020] (a) Pour titanium dioxide particles dried under vacuum at 120℃, deionized water, and sodium hexametaphosphate into a beaker to obtain a suspension. Emulsify the suspension using an emulsifier for 20-30 minutes, then place it in an ultrasonic instrument for ultrasonic dispersion. During this process, add a certain amount of deionized water to adjust the suspension concentration to 10 mg / mL. Use a concentration of 1.0 mol·L⁻¹. -1 The pH of the suspension was adjusted to 9.5-10.5 with NaOH solution, wherein the mass of sodium hexametaphosphate was 0.02% of the mass of titanium dioxide particles;

[0021] (b) Transfer to a three-necked flask and place in an oil bath at 85°C. Adjust the rotation speed to 400-550 rpm and heat and stir. Add dilute sulfuric acid and sodium silicate solution dropwise to both sides of the three-necked flask simultaneously. Adjust the amount of dilute sulfuric acid and sodium silicate solution added to make the pH of the suspension 9.5-10.0. Then age for 4-6 hours (the reaction aging time should not be too long to prevent densification caused by self-gelling. Utilize the inner amino layer to allow the UV stabilizer to diffuse in).

[0022] (c) After the reaction is complete, add the silane coupling agent dropwise while keeping the rotation speed constant. After 1-2 hours, centrifuge and wash with ethanol (to make the silane coupling agent spread out) 1-3 times. Dry at 80°C for 24 hours. The mass of the silane coupling agent is 3-5 wt% of the mass of the titanium dioxide particles.

[0023] The present invention also provides the application of the multilayer coated titanium dioxide organic-inorganic hybrid particles as described above for the preparation of fibers.

[0024] As a preferred technical solution:

[0025] As described above, the fiber is a PET pre-oriented yarn, and the content of multi-layered coated titanium dioxide organic-inorganic hybrid particles in the PET pre-oriented yarn is 3-8 wt%.

[0026] The preparation process of PET pre-oriented yarn is as follows: First, multi-layer coated titanium dioxide organic-inorganic hybrid particles are mixed with PET powder in a high-speed mixer for 10-20 minutes. Then, the mixture is melt-extruded at 280-290℃ to produce a masterbatch with a multi-layer coated titanium dioxide organic-inorganic hybrid particle content of 50-70wt%. Finally, the masterbatch is added to the PET pre-oriented yarn production equipment. After spinning, PET pre-oriented yarn (75D specification) is obtained.

[0027] The spinning process parameters include: melt conveying pipe temperature 285-290℃, spinning box temperature 295-300℃, side blowing air velocity 0.3-0.8m / s, first roller temperature 80-100℃, first roller speed 2300-2400m / min, second roller temperature 120-130℃, second roller speed 3700-3900m / min, spinning speed 2600-2700m / min, and winding speed 4300-4600m / min;

[0028] PET pre-oriented yarn is woven into a fabric sample by a shuttle loom. The fabric sample is tested according to GB / T 18830-2009 and has a UPF>50 and UVA<5%. According to GTTC / GF TM 091-2022, the blocking rate of ultraviolet and visible light is ≥99%.

[0029] Beneficial effects:

[0030] (1) The present invention modifies the surface of titanium dioxide particles to construct a multi-layer structure. When subjected to ultraviolet radiation, the organic anti-ultraviolet agent layer and titanium dioxide particles first absorb ultraviolet radiation in the 290-400 nm band. For ultraviolet radiation in the 350-400 nm band, which can only be scattered, the titanium dioxide particles rescatter it to the organic anti-ultraviolet agent layer and are absorbed again. Through the interface between the titanium dioxide particles and the silane coupling agent layer formed in the multi-layer coating, and the interface between the silane coupling agent layer and the organic anti-ultraviolet agent layer, refraction and scattering occur continuously, which can effectively enhance the absorption of ultraviolet radiation in the 290-400 nm band, and the absorption rate can reach more than 99.9%.

[0031] (2) The product prepared by the present invention has a high blocking rate for ultraviolet and visible light, which can further improve its application potential in the field of ultraviolet protection. Attached Figure Description

[0032] Figure 1 This is a cross-sectional view of the multilayer coated titanium dioxide organic-inorganic hybrid particles of the present invention;

[0033] Among them, 1-titanium dioxide particles, 2-silane coupling agent layer, and 3-organic UV stabilizer layer. Detailed Implementation

[0034] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0035] The test methods for the relevant performance indicators in the following embodiments and comparative examples are as follows:

[0036] Ultraviolet Absorption Rate: The powder was pressed into a 0.5 mm thin sheet, and the intensity I of the ultraviolet light transmitted through the sample was measured using a UV-Vis spectrophotometer (Shimadzu UV-2600). The absorbance A was calculated using the Lambert-Beer method: A = log(I0 / I), where I0 is the intensity of the ultraviolet monochromatic light from the spectrophotometer, and the ultraviolet absorption rate is 1 - 10. -A ×100%.

[0037] UPF (ultraviolet protection factor) and UVA (sunlight ultraviolet radiation): The fabric samples prepared in each example were measured according to GB / T 18830-2009 standard.

[0038] The blocking rate of ultraviolet and visible light: The fabric samples prepared in each example were measured according to the GTTC / GF TM 091-2022 standard "Test of Ultraviolet, Visible and Near Infrared Blocking Rate of Textiles" independently developed by Guangzhou Inspection Group.

[0039] Example A1

[0040] The preparation method of multilayer coated titanium dioxide organic-inorganic hybrid particles includes the following steps:

[0041] (1) Preparation of raw materials;

[0042] Titanium dioxide particles;

[0043] Deionized water

[0044] Sodium hexametaphosphate;

[0045] NaOH aqueous solution: concentration of 1.0 mol·L⁻¹ -1 ;

[0046] Dilute sulfuric acid: concentration 1 mol / L;

[0047] Sodium silicate solution: concentration 0.1 mol / L, solvent is water;

[0048] Silane coupling agent: KH550;

[0049] Ethanol;

[0050] Solvent: A 70% v / v aqueous solution of ethanol;

[0051] Sodium sulfite;

[0052] Organic UV protectant: 2-hydroxybenzophenone, CAS number 117-99-7;

[0053] (2) Preparation of titanium dioxide particles coated with silane coupling agent;

[0054] (2.1) Titanium dioxide particles dried under vacuum at 120℃, deionized water, and sodium hexametaphosphate were poured into a beaker to obtain a suspension. The suspension was emulsified for 20 min using an emulsifier and then ultrasonically dispersed in an ultrasonic instrument. During this process, deionized water was added to adjust the concentration of the suspension to 10 mg / mL, and the pH of the suspension was adjusted to 9.5 using NaOH aqueous solution. The mass of sodium hexametaphosphate was 0.02% of the mass of titanium dioxide particles.

[0055] (2.2) Transfer the pH-adjusted suspension to a three-necked flask, place it in an oil bath at 85°C, adjust the rotation speed to 400 rpm, heat and stir, add dilute sulfuric acid and sodium silicate solution dropwise to both sides of the three-necked flask at the same time, adjust the amount of dilute sulfuric acid and sodium silicate solution added so that the pH value of the suspension is 9.5, and then age for 4 hours.

[0056] (2.3) After aging, silane coupling agent was added dropwise while maintaining a constant rotation speed. After 1 hour, the mixture was centrifuged, washed once with ethanol, and dried at 80°C for 24 hours to obtain titanium dioxide particles coated with silane coupling agent; wherein the mass of silane coupling agent was 3 wt% of the mass of titanium dioxide particles.

[0057] (3) Disperse the titanium dioxide particles coated with silane coupling agent obtained in step (2) in a solvent to obtain a dispersion with a concentration of 8 mg / mL, add sodium sulfite to it and stir at 400 rpm for 0.4 h; wherein, the amount of sodium sulfite added per milliliter of solvent is 0.1 mg;

[0058] (4) After the stirring in step (3) is completed, add the organic UV stabilizer and stir at 400 rpm for 30 min. Heat to the solvent reflux temperature and keep warm for 24 h. Then wash with deionized water 4 times and finally crush with a pulverizer to obtain multi-layer coated titanium dioxide organic-inorganic hybrid particles. The mass ratio of the organic UV stabilizer to the silane coupling agent coated titanium dioxide particles is 1:100.

[0059] The final multilayer coated titanium dioxide organic-inorganic hybrid particles (the cross-sectional view of which is shown in Figure 1) were obtained. Figure 1 (As shown) It consists of titanium dioxide particles 1 and a silane coupling agent layer 2 and an organic UV stabilizer layer 3, which are sequentially coated on its surface from the inside out;

[0060] The average particle size of titanium dioxide particles 1 is 200 nm, the thickness of silane coupling agent layer 2 is 50 nm, and the thickness of organic UV stabilizer layer 3 is 20 nm.

[0061] The ultraviolet absorption rate of the multilayer coated titanium dioxide organic-inorganic hybrid particles is 99%.

[0062] Comparative Example A1

[0063] A method for preparing multilayer coated titanium dioxide organic-inorganic hybrid particles is basically the same as in Example A1, except that the mass of the silane coupling agent is adjusted to 2.5 wt% of the mass of the titanium dioxide particles, so that the thickness of the silane coupling agent layer of the finally obtained multilayer coated titanium dioxide organic-inorganic hybrid particles is 47 nm, while the thickness of the organic anti-ultraviolet agent layer remains unchanged.

[0064] The ultraviolet absorption rate of the multilayer coated titanium dioxide organic-inorganic hybrid particles is 87.2%.

[0065] Comparative Example A2

[0066] A method for preparing multilayer coated titanium dioxide organic-inorganic hybrid particles is basically the same as in Example A1, except that the mass of the silane coupling agent is adjusted to 5.5 wt% of the mass of the titanium dioxide particles, so that the thickness of the silane coupling agent layer of the finally obtained multilayer coated titanium dioxide organic-inorganic hybrid particles is 73 nm, while the thickness of the organic anti-ultraviolet agent layer remains unchanged.

[0067] The ultraviolet absorption rate of the multilayer coated titanium dioxide organic-inorganic hybrid particles is 85.5%.

[0068] Comparative Example A3

[0069] A method for preparing multilayer coated titanium dioxide organic-inorganic hybrid particles is basically the same as in Example A1, except that the mass ratio of the organic UV stabilizer to the silane coupling agent coated titanium dioxide particles is adjusted to 0.5:100, so that the thickness of the organic UV stabilizer layer of the finally obtained multilayer coated titanium dioxide organic-inorganic hybrid particles is 16 nm, while the thickness of the silane coupling agent layer remains unchanged.

[0070] The ultraviolet absorption rate of the multilayer coated titanium dioxide organic-inorganic hybrid particles is 84.6%.

[0071] Comparative Example A4

[0072] A method for preparing multilayer coated titanium dioxide organic-inorganic hybrid particles is basically the same as in Example A1, except that the mass ratio of the organic UV stabilizer to the silane coupling agent coated titanium dioxide particles is adjusted to 4:100, so that the thickness of the organic UV stabilizer layer of the finally obtained multilayer coated titanium dioxide organic-inorganic hybrid particles is 35 nm, while the thickness of the silane coupling agent layer remains unchanged.

[0073] The ultraviolet absorption rate of the multilayer coated titanium dioxide organic-inorganic hybrid particles is 86.8%.

[0074] Comparing Comparative Examples A1-A4 with Example A1, it can be seen that the thickness of the silane coupling agent layer and the thickness of the organic UV stabilizer layer need to be within a moderate range. If the thickness is too large, it will affect the absorption effect of titanium dioxide in the coated particles on ultraviolet light in the 290-400 nm band, while if the thickness is too small, it will affect the absorption effect of the coating layer on ultraviolet light in the 350-400 nm band, ultimately leading to a weakening of the absorption effect of the coated particles on ultraviolet light.

[0075] Example A2

[0076] The preparation method of multilayer coated titanium dioxide organic-inorganic hybrid particles includes the following steps:

[0077] (1) Preparation of raw materials;

[0078] Titanium dioxide particles;

[0079] Deionized water

[0080] Sodium hexametaphosphate;

[0081] NaOH aqueous solution: concentration of 1.0 mol·L⁻¹ -1 ;

[0082] Dilute sulfuric acid: concentration 1.5 mol / L;

[0083] Sodium silicate solution: concentration 0.15 mol / L, solvent is water;

[0084] Silane coupling agent: KH550;

[0085] Ethanol;

[0086] Solvent: An aqueous solution of ethanol with a concentration of 80% v / v;

[0087] Sodium sulfite;

[0088] Organic UV stabilizer: Benzotriazolyldodecyl p-cresol, CAS No. 125304-04-3;

[0089] (2) Preparation of titanium dioxide coated with silane coupling agent;

[0090] (2.1) Titanium dioxide particles dried under vacuum at 120℃, deionized water, and sodium hexametaphosphate were poured into a beaker to obtain a suspension. The suspension was emulsified using an emulsifier for 22 min and then ultrasonically dispersed in an ultrasonic instrument. During this process, deionized water was added to adjust the concentration of the suspension to 10 mg / mL, and the pH of the suspension was adjusted to 9.8 using NaOH aqueous solution. The mass of sodium hexametaphosphate was 0.02% of the mass of titanium dioxide particles.

[0091] (2.2) Transfer the pH-adjusted suspension to a three-necked flask and place it in an oil bath at 85°C. Adjust the rotation speed to 475 rpm and heat and stir. Add dilute sulfuric acid and sodium silicate solution dropwise to both sides of the three-necked flask at the same time. Adjust the amount of dilute sulfuric acid and sodium silicate solution added so that the pH value of the suspension is 9.6, and then age for 4.5 hours.

[0092] (2.3) After aging, silane coupling agent was added dropwise while maintaining a constant rotation speed. After 1.2 hours, the mixture was centrifuged, washed twice with ethanol, and dried at 80°C for 24 hours to obtain titanium dioxide particles coated with silane coupling agent; wherein the mass of silane coupling agent was 3.5 wt% of the mass of titanium dioxide particles.

[0093] (3) Disperse the titanium dioxide particles coated with silane coupling agent obtained in step (2) in a solvent to obtain a dispersion with a concentration of 8.5 mg / mL, add sodium sulfite to it and stir at a speed of 475 rpm for 0.6 h; wherein, the amount of sodium sulfite added per milliliter of solvent is 0.3 mg;

[0094] (4) After the stirring in step (3) is completed, add the organic UV stabilizer and stir at 480 rpm for 40 min. Heat to the solvent reflux temperature and keep warm for 24 h. Then wash with deionized water 4 times and finally crush with a pulverizer to obtain multi-layer coated titanium dioxide organic-inorganic hybrid particles. The mass ratio of the organic UV stabilizer to the silane coupling agent coated titanium dioxide particles is 1.5:100.

[0095] The resulting multilayer coated titanium dioxide organic-inorganic hybrid particles consist of titanium dioxide particles and, from the inside out, a silane coupling agent layer and an organic UV stabilizer layer that are sequentially coated on their surface.

[0096] The average particle size of the titanium dioxide particles is 180 nm, the thickness of the silane coupling agent layer is 55 nm, and the thickness of the organic UV stabilizer layer is 22 nm.

[0097] The ultraviolet absorption rate of the multilayer coated titanium dioxide organic-inorganic hybrid particles is 99.2%.

[0098] Example A3

[0099] The preparation method of multilayer coated titanium dioxide organic-inorganic hybrid particles includes the following steps:

[0100] (1) Preparation of raw materials;

[0101] Titanium dioxide particles;

[0102] Deionized water

[0103] Sodium hexametaphosphate;

[0104] NaOH aqueous solution: concentration of 1.0 mol·L⁻¹ -1 ;

[0105] Dilute sulfuric acid: concentration 2 mol / L;

[0106] Sodium silicate solution: concentration 0.2 mol / L, solvent is water;

[0107] Silane coupling agent: KH550;

[0108] Ethanol;

[0109] Solvent: A 70% v / v aqueous solution of acetone;

[0110] Sodium sulfite;

[0111] Organic UV protectant: 2-[4,6-bis(2,4-dimethylyl)-1,3,5-triazin-2-yl]-5-(octoxy)phenol, CAS number 2725-22-6;

[0112] (2) Preparation of titanium dioxide particles coated with silane coupling agent;

[0113] (2.1) Titanium dioxide particles dried under vacuum at 120℃, deionized water, and sodium hexametaphosphate were poured into a beaker to obtain a suspension. The suspension was emulsified using an emulsifier for 25 min and then ultrasonically dispersed in an ultrasonic instrument. During this process, deionized water was added to adjust the concentration of the suspension to 10 mg / mL, and the pH of the suspension was adjusted to 10 using NaOH aqueous solution. The mass of sodium hexametaphosphate was 0.02% of the mass of titanium dioxide particles.

[0114] (2.2) Transfer the pH-adjusted suspension to a three-necked flask, place it in an oil bath at 85°C, adjust the rotation speed to 500 rpm, heat and stir, add dilute sulfuric acid and sodium silicate solution dropwise to both sides of the three-necked flask at the same time, adjust the amount of dilute sulfuric acid and sodium silicate solution added so that the pH value of the suspension is 9.7, and then age for 5 hours.

[0115] (2.3) After aging, silane coupling agent was added dropwise while maintaining a constant rotation speed. After 1.5 hours, the mixture was centrifuged, washed twice with ethanol, and dried at 80°C for 24 hours to obtain titanium dioxide particles coated with silane coupling agent; wherein the mass of silane coupling agent was 4 wt% of the mass of titanium dioxide particles.

[0116] (3) Disperse the titanium dioxide particles coated with silane coupling agent obtained in step (2) in a solvent to obtain a dispersion with a concentration of 9 mg / mL, add sodium sulfite to it and stir at 500 rpm for 0.8 h; wherein, the amount of sodium sulfite added per milliliter of solvent is 0.5 mg;

[0117] (4) After the stirring in step (3) is completed, add the organic UV stabilizer and stir at 500 rpm for 50 min. Heat to the solvent reflux temperature and keep warm for 24 h. Then wash with deionized water 4 times and finally crush with a pulverizer to obtain multi-layer coated titanium dioxide organic-inorganic hybrid particles. The mass ratio of the organic UV stabilizer to the silane coupling agent coated titanium dioxide particles is 2:100.

[0118] The resulting multilayer coated titanium dioxide organic-inorganic hybrid particles consist of titanium dioxide particles and, from the inside out, a silane coupling agent layer and an organic UV stabilizer layer that are sequentially coated on their surface.

[0119] The average particle size of the titanium dioxide particles is 165 nm, the thickness of the silane coupling agent layer is 60 nm, and the thickness of the organic UV stabilizer layer is 25 nm.

[0120] The ultraviolet absorption rate of the multilayer coated titanium dioxide organic-inorganic hybrid particles is 99.5%.

[0121] Example A4

[0122] The preparation method of multilayer coated titanium dioxide organic-inorganic hybrid particles includes the following steps:

[0123] (1) Preparation of raw materials;

[0124] Titanium dioxide particles;

[0125] Deionized water

[0126] Sodium hexametaphosphate;

[0127] NaOH aqueous solution: concentration of 1.0 mol·L⁻¹ -1 ;

[0128] Dilute sulfuric acid: concentration 2.5 mol / L;

[0129] Sodium silicate solution: concentration 0.25 mol / L, solvent is water;

[0130] Silane coupling agent: KH550;

[0131] Ethanol;

[0132] Solvent: A 75% v / v aqueous solution of acetone;

[0133] Sodium sulfite;

[0134] Organic UV stabilizer: a mixture of 2-hydroxybenzophenone (CAS No. 117-99-7) and benzotriazolyldodecyl p-cresol (CAS No. 125304-04-3) in a mass ratio of 1:1;

[0135] (2) Preparation of titanium dioxide particles coated with silane coupling agent;

[0136] (2.1) Titanium dioxide particles dried under vacuum at 120℃, deionized water, and sodium hexametaphosphate were poured into a beaker to obtain a suspension. The suspension was emulsified using an emulsifier for 28 min and then ultrasonically dispersed in an ultrasonic instrument. During this process, deionized water was added to adjust the concentration of the suspension to 10 mg / mL, and the pH of the suspension was adjusted to 10.2 using NaOH aqueous solution. The mass of sodium hexametaphosphate was 0.02% of the mass of titanium dioxide particles.

[0137] (2.2) Transfer the pH-adjusted suspension to a three-necked flask and place it in an oil bath at 85°C. Adjust the rotation speed to 525 rpm and heat and stir. Add dilute sulfuric acid and sodium silicate solution dropwise to both sides of the three-necked flask at the same time. Adjust the amount of dilute sulfuric acid and sodium silicate solution added so that the pH value of the suspension is 9.9, and then age for 5.5 hours.

[0138] (2.3) After aging, silane coupling agent was added dropwise while maintaining a constant rotation speed. After 1.8 hours, the mixture was centrifuged, washed three times with ethanol, and dried at 80°C for 24 hours to obtain titanium dioxide particles coated with silane coupling agent; wherein the mass of silane coupling agent was 4.5 wt% of the mass of titanium dioxide particles.

[0139] (3) Disperse the titanium dioxide particles coated with silane coupling agent obtained in step (2) in a solvent to obtain a dispersion with a concentration of 9.5 mg / mL, add sodium sulfite to it and stir at a speed of 525 rpm for 0.85 h; wherein, the amount of sodium sulfite added per milliliter of solvent is 0.8 mg;

[0140] (4) After the stirring in step (3) is completed, add the organic UV stabilizer and stir at 520 rpm for 55 min. Heat to the solvent reflux temperature and keep warm for 24 h. Then wash with deionized water 5 times and finally crush with a pulverizer to obtain multi-layer coated titanium dioxide organic-inorganic hybrid particles. The mass ratio of the organic UV stabilizer to the silane coupling agent coated titanium dioxide particles is 2.5:100.

[0141] The resulting multilayer coated titanium dioxide organic-inorganic hybrid particles consist of titanium dioxide particles and, from the inside out, a silane coupling agent layer and an organic UV stabilizer layer that are sequentially coated on their surface.

[0142] The average particle size of the titanium dioxide particles is 160 nm, the thickness of the silane coupling agent layer is 65 nm, and the thickness of the organic UV stabilizer layer is 28 nm.

[0143] The ultraviolet absorption rate of the multilayer coated titanium dioxide organic-inorganic hybrid particles is 99.8%.

[0144] Example A5

[0145] The preparation method of multilayer coated titanium dioxide organic-inorganic hybrid particles includes the following steps:

[0146] (1) Preparation of raw materials;

[0147] Titanium dioxide particles;

[0148] Deionized water

[0149] Sodium hexametaphosphate;

[0150] NaOH aqueous solution: concentration of 1.0 mol·L⁻¹ -1 ;

[0151] Dilute sulfuric acid: concentration 3 mol / L;

[0152] Sodium silicate solution: concentration 0.3 mol / L, solvent is water;

[0153] Silane coupling agent: KH550;

[0154] Ethanol;

[0155] Solvent: 80% v / v aqueous acetone solution;

[0156] Sodium sulfite;

[0157] Organic UV stabilizer: Benzotriazolyldodecyl p-cresol, CAS No. 125304-04-3;

[0158] (2) Preparation of titanium dioxide particles coated with silane coupling agent;

[0159] (2.1) Titanium dioxide particles dried under vacuum at 120℃, deionized water, and sodium hexametaphosphate were poured into a beaker to obtain a suspension. The suspension was emulsified using an emulsifier for 30 min and then ultrasonically dispersed in an ultrasonic instrument. During this process, deionized water was added to adjust the concentration of the suspension to 10 mg / mL, and the pH of the suspension was adjusted to 10.5 using NaOH aqueous solution. The mass of sodium hexametaphosphate was 0.02% of the mass of titanium dioxide particles.

[0160] (2.2) Transfer the pH-adjusted suspension to a three-necked flask, place it in an oil bath at 85°C, adjust the rotation speed to 550 rpm, heat and stir, add dilute sulfuric acid and sodium silicate solution dropwise to both sides of the three-necked flask at the same time, adjust the amount of dilute sulfuric acid and sodium silicate solution added so that the pH value of the suspension is 10, and then age for 6 hours.

[0161] (2.3) After aging, silane coupling agent was added dropwise while maintaining a constant rotation speed. After 2 hours, the mixture was centrifuged, washed three times with ethanol, and dried at 80°C for 24 hours to obtain titanium dioxide particles coated with silane coupling agent. The mass of the silane coupling agent was 5 wt% of the mass of the titanium dioxide particles.

[0162] (3) Disperse the titanium dioxide particles coated with silane coupling agent obtained in step (2) in a solvent to obtain a dispersion with a concentration of 10 mg / mL, add sodium sulfite to it and stir at a speed of 550 rpm for 1 h; wherein, the amount of sodium sulfite added per milliliter of solvent is 1 mg.

[0163] (4) After the stirring in step (3) is completed, add the organic UV stabilizer and stir at 550 rpm for 60 min. Heat to the solvent reflux temperature and keep warm for 24 h. Then wash with deionized water 5 times and finally crush with a pulverizer to obtain multi-layer coated titanium dioxide organic-inorganic hybrid particles. The mass ratio of the organic UV stabilizer to the silane coupling agent coated titanium dioxide is 3:100.

[0164] The resulting multilayer coated titanium dioxide organic-inorganic hybrid particles consist of titanium dioxide particles and, from the inside out, a silane coupling agent layer and an organic UV stabilizer layer that are sequentially coated on their surface.

[0165] The average particle size of the titanium dioxide particles is 150 nm, the thickness of the silane coupling agent layer is 70 nm, and the thickness of the organic UV stabilizer layer is 30 nm.

[0166] The ultraviolet absorption rate of the multilayer coated titanium dioxide organic-inorganic hybrid particles is 99.9%.

[0167] Example B1

[0168] The method for preparing PET pre-oriented yarns using multilayer coated titanium dioxide organic-inorganic hybrid particles comprises the following steps:

[0169] (1) Preparation of raw materials;

[0170] Multilayer coated titanium dioxide organic-inorganic hybrid particles: prepared in Example A1;

[0171] PET powder: Manufacturer is China Petroleum & Chemical Corporation, grade is FG720;

[0172] (2) The multi-layer coated titanium dioxide organic-inorganic hybrid particles and PET powder are mixed in a high-speed mixer for 10 min, and then melt-extruded at 280°C to produce a masterbatch with a multi-layer coated titanium dioxide organic-inorganic hybrid particle content of 50 wt%. Finally, the masterbatch is added to the PET pre-oriented yarn production equipment. After spinning, PET pre-oriented yarn (specification 75D) is obtained; wherein, the content of multi-layer coated titanium dioxide organic-inorganic hybrid particles in the PET pre-oriented yarn is 3 wt%.

[0173] The spinning process parameters include: melt conveying pipe temperature 290℃, spinning box temperature 295℃, side blowing air velocity 0.8m / s, first roller temperature 100℃, first roller speed 2300m / min, second roller temperature 130℃, second roller speed 3700m / min, spinning speed 2600m / min, and winding speed 4300m / min.

[0174] The PET pre-oriented yarn obtained above is used to weave a fabric sample using a twill weft elastic loom.

[0175] The final fabric sample had a weight of 152 gsm (g / m²), a UPF of 55, a UVA of 4%, and a blocking rate of 99.2% for ultraviolet and visible light.

[0176] Example B2

[0177] The method for preparing PET pre-oriented yarns using multilayer coated titanium dioxide organic-inorganic hybrid particles comprises the following steps:

[0178] (1) Preparation of raw materials;

[0179] Multilayer coated titanium dioxide organic-inorganic hybrid particles: prepared in Example A2;

[0180] PET powder: Manufacturer is China Petroleum & Chemical Corporation, grade is FG720;

[0181] (2) The multi-layer coated titanium dioxide organic-inorganic hybrid particles and PET powder are mixed in a high-speed mixer for 12 min, and then melt-extruded at 282°C to produce a masterbatch with a multi-layer coated titanium dioxide organic-inorganic hybrid particle content of 55 wt%. Finally, the masterbatch is added to the PET pre-oriented yarn production equipment. After spinning, PET pre-oriented yarn (75D specification) is obtained; wherein, the content of multi-layer coated titanium dioxide organic-inorganic hybrid particles in the PET pre-oriented yarn is 4 wt%.

[0182] The spinning process parameters include: melt conveying pipe temperature 288℃, spinning box temperature 296℃, side blowing air velocity 0.7m / s, first roller temperature 95℃, first roller speed 2320m / min, second roller temperature 128℃, second roller speed 3750m / min, spinning speed 2630m / min, and winding speed 4400m / min.

[0183] The PET pre-oriented yarn obtained above is used to weave a fabric sample using a twill weft elastic loom.

[0184] The final fabric sample had a weight of 152 gsm, a UPF of 65, a UVA of 3%, and a blocking rate of 99.4% for ultraviolet and visible light.

[0185] Example B3

[0186] The method for preparing PET pre-oriented yarns using multilayer coated titanium dioxide organic-inorganic hybrid particles comprises the following steps:

[0187] (1) Preparation of raw materials;

[0188] Multilayer coated titanium dioxide organic-inorganic hybrid particles: prepared in Example A3;

[0189] PET powder: Manufacturer is China Petroleum & Chemical Corporation, grade is FG720;

[0190] (2) The multi-layer coated titanium dioxide organic-inorganic hybrid particles and PET powder are mixed in a high-speed mixer for 15 min, and then melt-extruded at 285°C to produce a masterbatch with a multi-layer coated titanium dioxide organic-inorganic hybrid particle content of 60 wt%. Finally, the masterbatch is added to the PET pre-oriented yarn production equipment. After spinning, PET pre-oriented yarn (75D specification) is obtained; wherein, the content of multi-layer coated titanium dioxide organic-inorganic hybrid particles in the PET pre-oriented yarn is 6 wt%.

[0191] The spinning process parameters include: melt conveying pipe temperature 287℃, spinning box temperature 297℃, side blowing air velocity 0.6m / s, first roller temperature 90℃, first roller speed 2350m / min, second roller temperature 125℃, second roller speed 3800m / min, spinning speed 2650m / min, and winding speed 4500m / min.

[0192] The PET pre-oriented yarn obtained above is used to weave a fabric sample using a twill weft elastic loom.

[0193] The final fabric sample had a weight of 152 gsm, a UPF of 70, a UVA of 3%, and a blocking rate of 99.5% for ultraviolet and visible light.

[0194] Example B4

[0195] The method for preparing PET pre-oriented yarns using multilayer coated titanium dioxide organic-inorganic hybrid particles comprises the following steps:

[0196] (1) Preparation of raw materials;

[0197] Multilayer coated titanium dioxide organic-inorganic hybrid particles: prepared in Example A4;

[0198] PET powder: Manufacturer is China Petroleum & Chemical Corporation, grade is FG720;

[0199] (2) The multi-layer coated titanium dioxide organic-inorganic hybrid particles and PET powder are mixed in a high-speed mixer for 18 min, and then melt-extruded at 288°C to produce a masterbatch with a multi-layer coated titanium dioxide organic-inorganic hybrid particle content of 65 wt%. Finally, the masterbatch is added to the PET pre-oriented yarn production equipment. After spinning, PET pre-oriented yarn (specification 75D) is obtained; wherein, the content of multi-layer coated titanium dioxide organic-inorganic hybrid particles in the PET pre-oriented yarn is 8 wt%.

[0200] The spinning process parameters include: melt conveying pipe temperature 286℃, spinning box temperature 299℃, side blowing air velocity 0.5m / s, first roller temperature 86℃, first roller speed 2380m / min, second roller temperature 122℃, second roller speed 3850m / min, spinning speed 2680m / min, and winding speed 4500m / min.

[0201] The PET pre-oriented yarn obtained above is used to weave a fabric sample using a twill weft elastic loom.

[0202] The final fabric sample had a weight of 152 gsm, a UPF of 80, a UVA of 2%, and a blocking rate of 99.8% for ultraviolet and visible light.

[0203] Example B5

[0204] The method for preparing PET pre-oriented yarns using multilayer coated titanium dioxide organic-inorganic hybrid particles comprises the following steps:

[0205] (1) Preparation of raw materials;

[0206] Multilayer coated titanium dioxide organic-inorganic hybrid particles: prepared in Example A5;

[0207] PET powder: Manufacturer is China Petroleum & Chemical Corporation, grade is FG720;

[0208] (2) The multi-layer coated titanium dioxide organic-inorganic hybrid particles and PET powder are mixed in a high-speed mixer for 20 min, and then melt-extruded at 290°C to produce a masterbatch with a multi-layer coated titanium dioxide organic-inorganic hybrid particle content of 70 wt%. Finally, the masterbatch is added to the PET pre-oriented yarn production equipment. After spinning, PET pre-oriented yarn (75D specification) is obtained; wherein, the content of multi-layer coated titanium dioxide organic-inorganic hybrid particles in the PET pre-oriented yarn is 8 wt%.

[0209] The spinning process parameters include: melt conveying pipe temperature 285℃, spinning box temperature 300℃, side blowing air speed 0.3m / s, first roller temperature 80℃, first roller speed 2400m / min, second roller temperature 120℃, second roller speed 3900m / min, spinning speed 2700m / min, and winding speed 4600m / min.

[0210] The PET pre-oriented yarn obtained above is used to weave a fabric sample using a twill weft elastic loom.

[0211] The final fabric sample had a weight of 152 gsm, a UPF of 85, a UVA of 1%, and a blocking rate of 99.9% for ultraviolet and visible light.

Claims

1. Multilayer coated titanium dioxide organic-inorganic hybrid particles, characterized in that, It includes titanium dioxide particles and a silane coupling agent layer and an organic UV stabilizer layer that are sequentially coated on its surface from the inside out; The thickness of the silane coupling agent layer is 50-70 nm, and the thickness of the organic UV stabilizer layer is 20-30 nm.

2. The multilayer coated titanium dioxide organic-inorganic hybrid particles according to claim 1, characterized in that, The ultraviolet absorption rate of multi-layered titanium dioxide organic-inorganic hybrid particles is over 99.9%.

3. The multilayer coated titanium dioxide organic-inorganic hybrid particles according to claim 1, characterized in that, The average particle size of titanium dioxide particles is 150-200 nm.

4. The multilayer coated titanium dioxide organic-inorganic hybrid particles according to any one of claims 1 to 3, characterized in that, The silane coupling agent is KH550; the organic UV absorber is one or more of the following: benzophenone with phenolic hydroxyl groups, benzotriazole with phenolic hydroxyl groups, and triazine organic UV absorbers with phenolic hydroxyl groups.

5. The method for preparing multilayer-coated titanium dioxide organic-inorganic hybrid particles as described in claim 4, characterized in that, Organic UV stabilizers are chemically bonded to titanium dioxide particles coated with silane coupling agents, resulting in multi-layered titanium dioxide organic-inorganic hybrid particles.

6. The method according to claim 5, characterized in that, The specific process is as follows: Titanium dioxide particles coated with silane coupling agent are dispersed in a solvent to obtain a dispersion. Sodium sulfite is added to the dispersion and stirred at 400-550 rpm for 0.4-1 h. Then, an organic UV stabilizer is added and stirred at 400-550 rpm for 30-60 min. The temperature is raised to the solvent reflux temperature and kept at that temperature for 24 h. After post-treatment, multi-layered titanium dioxide organic-inorganic hybrid particles are obtained. The solvent is a good solvent for the organic UV stabilizer.

7. The method according to claim 6, characterized in that, The solvent is an aqueous solution of ethanol with a concentration of 70-80% v / v, an aqueous solution of acetone with a concentration of 70-80% v / v, or water; the concentration of the dispersion is 8-10 mg / mL; the amount of sodium sulfite added per milliliter of solvent is 0.1-1 mg; the mass ratio of the organic UV stabilizer to the titanium dioxide particles coated with the silane coupling agent is 1-3:

100.

8. The application of the multilayer coated titanium dioxide organic-inorganic hybrid particles as described in any one of claims 1-4, characterized in that, Used to prepare fibers.

9. The application according to claim 8, characterized in that, The fiber is a PET pre-oriented yarn, and the content of multi-layered coated titanium dioxide organic-inorganic hybrid particles in the PET pre-oriented yarn is 3-8 wt%. PET pre-oriented yarn is woven into a fabric sample by a shuttle loom. The fabric sample is tested according to GB / T 18830-2009 and has a UPF>50 and UVA<5%. According to GTTC / GF TM 091-2022, the blocking rate of ultraviolet and visible light is ≥99%.

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