Preparation method of photocatalytic antibacterial modified titanium dioxide, antibacterial composition, preparation method and application thereof

Abstract

The application relates to the field of photocatalysis, in particular to a photocatalytic antibacterial modified titanium dioxide preparation method, an antibacterial composition and a preparation method and application thereof, the preparation method of the antibacterial modified titanium dioxide comprises the following steps: ultrasonic dispersion of titanium dioxide in a polyethylene glycol aqueous solution for 15-20 min, pH adjustment to 5-6, EDC / NHS addition, and stirring activation for 20-30 min; antibacterial salt of polylysine is added, the temperature is increased to 45-50 DEG C, and reaction is carried out for 4-5 h to obtain antibacterial modified titanium dioxide. The application improves the problem of insufficient antibacterial performance of the existing photocatalytic titanium dioxide, provides antibacterial modified titanium dioxide, constructs a high-efficiency cooperative photocatalytic antibacterial system, and improves the long-acting antibacterial property and stability of the composition.

Description

Technical Field

[0001] This application relates to the field of photocatalysis technology, and in particular to a method for preparing photocatalytic antibacterial modified titanium dioxide, an antibacterial composition, the preparation method thereon, and its application. Background Technology

[0002] Nano-titanium dioxide, as a core antibacterial material in the field of photocatalysis, has advantages such as low cost, non-toxicity, good stability, long-lasting antibacterial effect, air purification, and self-cleaning. It has been widely used in many industries with antibacterial requirements, such as building coatings, medical devices, and optical substrate protection. For example, photocatalytic titanium dioxide-supported antibacterial compositions are used in prism plates to provide antibacterial effects. However, excessive addition of titanium dioxide can significantly reduce optical performance, and the haze is unacceptable for some products with high optical performance requirements.

[0003] More importantly, the long-term effectiveness of antibacterial function remains a significant challenge. Due to the lack of systematic optimization of the interfacial compatibility between the surface properties of nano-titanium dioxide and the resin emulsion, it is prone to aggregation in the composition. This makes it difficult to fully expose photocatalytic active sites and achieve sufficient contact with bacteria, thus restricting the full release of antibacterial efficiency. Furthermore, uneven dispersion further affects the optical uniformity of the coating. Traditional mechanical mixing fails to create a stable bond between the antibacterial components and the film-forming system. Some synergistic antibacterial components easily migrate and escape during contact with moisture or daily wiping, causing the coating's antibacterial efficacy to gradually decrease over time. Existing technologies have largely addressed this issue by adjusting the mixing ratio or adding dispersing agents, failing to fundamentally solve the stability problem of the antibacterial components and thus failing to meet the continuous antibacterial requirements of long-term use. Summary of the Invention

[0004] In order to improve the long-lasting antibacterial performance of photocatalytic antibacterial products, this application provides a method for preparing photocatalytic antibacterial modified titanium dioxide, an antibacterial composition, the preparation method thereon, and its application.

[0005] In a first aspect, this application provides a method for preparing photocatalytic antibacterial modified titanium dioxide, which adopts the following technical solution: The method for preparing antibacterial modified titanium dioxide includes: adding titanium dioxide to an aqueous solution of polyethylene glycol and ultrasonically dispersing it for 15-20 min, adjusting the pH to 5-6, adding EDC / NHS, and stirring and activating for 20-30 min; then adding polylysine antibacterial salt, heating to 45-50℃ and reacting for 4-5 h to obtain antibacterial modified titanium dioxide.

[0006] Preferably, the mass ratio of titanium dioxide to polylysine antibacterial salt is (3-5):1.

[0007] Secondly, this application provides an antibacterial composition comprising the photocatalytically antibacterial modified titanium dioxide described in the first aspect. The technical solution adopted is as follows: An antibacterial composition comprising the following components in weight percentages: 5.6-6.1% antibacterial modified titanium dioxide, 13.9-24.6% resin emulsion, 1.4-1.7% dispersant, 0.8-1.0% wetting agent, 0.5-0.8% film-forming aid, and 65.8-77.8% water; wherein the resin emulsion comprises modified styrene-butadiene emulsion, styrene-acrylic emulsion, and quaternary ammonium salt modified polysiloxane emulsion.

[0008] Preferably, the preparation method of modified styrene-butadiene emulsion includes: adding styrene-butadiene emulsion to an aqueous solution containing sodium bicarbonate, heating to 65-75℃ and stirring for 10-15 min, adding ammonium persulfate and hydroxyethyl acrylate, stirring at 75-80℃ for 1-2 h, adjusting the pH to 6.5-7.5, adding an organosilicon defoamer, and stirring for 10-15 min to obtain modified styrene-butadiene emulsion.

[0009] Preferably, the mass ratio of the modified styrene-butadiene emulsion, the styrene-acrylic emulsion, and the quaternary ammonium salt modified polysiloxane emulsion is (2.4-2.8):(1.5-1.9):(1.2-1.6).

[0010] Preferably, the dispersant is nonylphenol polyoxyethylene ether, and the wetting agent is fatty alcohol polyoxyethylene ether.

[0011] Preferably, the film-forming aid is a mixture of dodecayl alcohol ester and propylene glycol phenyl ether in a mass ratio of 3:1.

[0012] The inventors discovered that the antibacterial modified titanium dioxide of this application has an antibacterial synergistic effect with styrene-butadiene emulsion, styrene-acrylic emulsion, and quaternary ammonium salt modified polysiloxane emulsion, and has constructed a highly efficient photocatalytic antibacterial system, which improves the antibacterial long-term effect and stability of the composition, and prevents the problems of uneven dispersion of antibacterial components, excessively rapid decay of efficacy, and reduced photocatalytic performance.

[0013] Antibacterial modified titanium dioxide is used as the core antibacterial component. The antibacterial modification of nano titanium dioxide retains its photocatalytic activity and reduces its optical properties such as haze. The antibacterial modification improves its antibacterial performance. Furthermore, the antibacterial modification in this application optimizes the interaction with the resin emulsion system, thereby improving the antibacterial stability of the overall antibacterial composition and avoiding the decay of the coating's antibacterial efficacy. Styrene-butadiene emulsion (SBR) in resin emulsions possesses excellent film-forming properties and mechanical strength, enabling it to rapidly form a continuous and dense coating skeleton. This provides a stable foundation for the antibacterial modified titanium dioxide. Further modification allows the active sites in the molecular chains to interact more closely with other components, ensuring the integrity of the coating structure and preventing brittleness and peeling. Styrene-acrylic emulsion (SAC) exhibits considerable substrate adhesion and weather resistance, allowing it to adhere tightly to substrates, especially polystyrene, effectively enhancing the bonding between the coating and the substrate. This prevents coating peeling due to external wiping or environmental changes during long-term use, establishing a strong bond between the coating and the substrate and a dense and stable internal structure. This ensures that the antibacterial modified titanium dioxide is uniformly dispersed and firmly fixed within the coating, avoiding insufficient exposure of active sites due to agglomeration, guaranteeing the uniformity of antibacterial performance, and providing support for long-lasting antibacterial effects. The addition of polysiloxane emulsion, with its excellent hydrophobicity, chemical stability, and UV resistance, forms a protective layer on the surface and enhances the efficiency of reactive oxygen species generation, significantly improving the coating's anti-fouling properties and lifespan. The antibacterial groups introduced through quaternary ammonium salt modification enhance the ability to capture bacteria, making it easier for bacteria to approach the titanium dioxide surface and improving the photocatalytic sterilization effect. Simultaneously, the chemical stability of polysiloxane protects the crystal structure of the antibacterial modified titanium dioxide from damage, ensuring long-term photocatalytic activity. The quaternary ammonium salt-modified polysiloxane emulsion coating provides a dual guarantee of external barrier and internal component protection, delaying the loss of antibacterial components and coating aging. The synergy between the quaternary ammonium salt-modified polysiloxane emulsion and the antibacterial modified titanium dioxide enhances the efficiency of reactive oxygen species generation, and the quaternary ammonium salt groups enhance the ability to capture bacteria, making it easier for bacteria to approach the titanium dioxide surface and improving the photocatalytic sterilization effect. At the same time, the chemical stability of polysiloxane protects the crystal structure of the antibacterial modified titanium dioxide from damage, ensuring long-term photocatalytic activity.

[0014] The interaction between the modified styrene-butadiene emulsion and the quaternary ammonium salt modified polysiloxane emulsion and styrene-acrylic emulsion further enhances the synergy of the system, reduces coating porosity, and lowers the possibility of bacterial growth that could affect the antibacterial effect. The three-dimensional network structure formed by the resin emulsion uniformly encapsulates and fixes the antibacterial modified titanium dioxide, ensuring that it does not settle or leak during long-term use. This not only guarantees the high efficiency of antibacterial action but also achieves long-term maintenance of antibacterial performance through the improved stability of the coating structure, providing a reliable guarantee for the long-term and efficient application of the photocatalytic antibacterial composition.

[0015] The inventors discovered that introducing polylysine antibacterial salts into the surface of titanium dioxide exhibits excellent biocompatibility and antibacterial activity. It specifically adsorbs Gram-positive bacteria such as Staphylococcus aureus and Gram-negative bacteria such as Escherichia coli. Its polypeptide backbone can rapidly bind to bacterial cell membranes through electrostatic interactions, disrupting cell membrane integrity and intracellular osmotic pressure balance, thus achieving targeted sterilization. After antibacterial treatment, the polylysine antibacterial salts specifically adsorb bacteria and accumulate on the titanium dioxide surface, enhancing antibacterial performance and shortening the diffusion distance of reactive oxygen species generated by photocatalysis. This allows reactive oxygen species to more efficiently oxidize and decompose bacterial organisms, significantly improving sterilization efficiency. Simultaneously, the antibacterial groups are firmly coated and fixed on the titanium dioxide surface, avoiding the problems of easy migration and loss of antibacterial components in traditional physical mixing, providing a structural basis for long-lasting antibacterial effects. Therefore, if the content of polylysine antibacterial salt is too low, the specific adsorption and dual bactericidal effects will be weakened, and the antibacterial efficiency will decrease; if the content of polylysine antibacterial salt is too high, its molecular chain entanglement may reduce the dispersibility of titanium dioxide particles, affecting the uniformity and optical properties of the coating, and ultimately affecting the long-term stability. At the same time, the modified styrene-butadiene emulsion can interact with the polylysine antibacterial salt on the surface of antibacterial modified titanium dioxide, firmly fixing the antibacterial modified titanium dioxide on the emulsion molecular chain, effectively inhibiting its aggregation and migration, ensuring uniform exposure of antibacterial sites and photocatalytic active sites, and strengthening the binding stability with the resin system, avoiding the loss of antibacterial components during long-term use, and providing structural support for long-term antibacterial effect.

[0016] Modified styrene-butadiene emulsion interacts with styrene-acrylic emulsion and quaternary ammonium salt modified polysiloxane emulsion to achieve stable coating film formation, fix antibacterial components, and achieve long-lasting antibacterial effect. If the content of styrene-acrylic emulsion is too low, its adhesion to the substrate is insufficient, resulting in poor bonding between the coating and the substrate, making it easy to peel off due to external wiping or environmental aging, thus compromising the stability of the antibacterial system. If the content of quaternary ammonium salt modified polysiloxane emulsion is too low, its chemical stability and antibacterial interaction will be weakened, reducing the adsorption and bactericidal effect and compromising the overall long-lasting antibacterial performance.

[0017] The inventors discovered that the interaction of the film-forming aids in the proportions of this application not only ensures uniform film formation, adhesion, and photocatalytic activity, but also optimizes the structural stability of the coating, further enhancing the long-lasting antibacterial performance of the system. The dodecyl alcohol ester possesses excellent film-forming promoting ability, effectively lowering the minimum film-forming temperature of the resin emulsion. This facilitates the formation of a continuous and dense coating from modified styrene-butadiene emulsions, styrene-acrylic emulsions, and quaternary ammonium salt-modified polysiloxane emulsions, reducing porosity defects and preventing bacterial invasion and loss of antibacterial components. Furthermore, the good compatibility and solubility of propylene glycol phenyl ether enhance the compatibility of the film-forming aids with the water-based system and various resin components.

[0018] Thirdly, this application provides a method for preparing an antibacterial composition, employing the following technical solution: A method for preparing an antibacterial composition includes the following preparation steps: S1. Take antibacterial modified titanium dioxide and add it to water and stir for 20-30 minutes to obtain solution A; S2. Take the resin emulsion, add the dispersant, and stir to mix to obtain solution B; S3. Add the solution B obtained in step S2 to the solution A obtained in step S1, add wetting agent and film-forming aid, stir and mix, adjust the pH value of the system to 7-8, discharge the material, and obtain the antibacterial composition.

[0019] Fourthly, this application provides the application of a photocatalytic antibacterial composition in a prism plate.

[0020] Preferably, the prism plate is made of polystyrene.

[0021] By optimizing the substrate material to which the antibacterial composition of this application adheres, adhesion can be further improved, thereby preventing the coating from migrating out during routine wiping and reducing the long-term antibacterial efficacy of the coating.

[0022] In summary, this application includes at least one of the following beneficial technical effects: 1. The antibacterial modified titanium dioxide of this application has an antibacterial synergistic effect with styrene-butadiene emulsion, styrene-acrylic emulsion and quaternary ammonium salt modified polysiloxane emulsion, and constructs a highly efficient photocatalytic antibacterial system, which improves the antibacterial long-term effect and stability of the composition, and prevents the problems of uneven dispersion of antibacterial components, rapid performance decay and reduced photocatalytic performance.

[0023] 2. The antibacterial modified titanium dioxide of this application enables the antibacterial composition to possess highly efficient photocatalytic properties and long-lasting and stable antibacterial activity. Attached Figure Description

[0024] Figure 1 A photograph of the photocatalytic antibacterial composition prepared in Example 1 after standing for 48 hours.

[0025] Figure 2 Comparison of the photocatalytic antibacterial composition prepared in Example 1 with Rhodamine B before and after UV irradiation (top and bottom).

[0026] Figure 3 Comparison of the photocatalytic antibacterial composition prepared in Example 1 before (left) and after (right) irradiation by a 25W panel lamp. Detailed Implementation

[0027] The present application will be further described in detail below with reference to embodiments and comparative examples: Some of the raw materials used in the examples and comparative examples are as follows: Nano titanium dioxide (anatase type), product number: XFI83, purchased from Nanjing Xianfeng Nanomaterials Technology Co., Ltd.; Dispersant: Nonylphenol polyoxyethylene ether, purchased from Shanghai Maclean; Wetting agent: Fatty alcohol polyoxyethylene ether AEO-9; Organosilicon defoamer, model BYK-066N; Styrene-butadiene emulsion (viscosity: 800Mpa.s), purchased from Jinan Zhongao Chemical Co., Ltd.; Styrene-acrylic emulsion, model: ROSF-1998A, Foshan Rosef Technology Co., Ltd.; Hydroxy-coated polysiloxane emulsion, model: PC15326; Polylysine antibacterial salt: Polylysine hydrochloride BR, 95%, purchased from Shanghai Yuanye Biotechnology Co., Ltd., product number: S25425; Ammonia water: 25% ammonia solution; Unless otherwise specified, all raw materials used in the examples and comparative examples are conventional products that can be purchased commercially.

[0028] Preparation Example 1 Preparation of antibacterial modified titanium dioxide: Take 80g of titanium dioxide and add it to 500ml of aqueous solution containing 5g of polyethylene glycol. Disperse it by ultrasonication for 20min. Add 0.05mol / L PBS buffer to adjust the pH to 6. Add 2.5g of EDC and 1.6g of NHS. Stir and activate for 30min. Then add 20g of polylysine hydrochloride. Heat to 45℃ and react for 5h. Centrifuge at 5000r / min for 20min. Wash with water 4 times. Vacuum dry at 60℃ for 6h. Grind and pass through a 300-mesh sieve to obtain antibacterial modified titanium dioxide.

[0029] Preparation Example 2 Preparation of antibacterial modified titanium dioxide: Take 85g of titanium dioxide and add it to 500ml of aqueous solution containing 5g of polyethylene glycol. Disperse it by ultrasonication for 20min. Add 0.05mol / L PBS buffer to adjust the pH to 6. Add 2.5g of EDC and 1.6g of NHS. Stir and activate for 30min. Then add 15g of polylysine hydrochloride. Heat to 45℃ and react for 5h. Centrifuge at 5000r / min for 20min. Wash with water 4 times. Vacuum dry at 60℃ for 6h. Grind and pass through a 300-mesh sieve to obtain antibacterial modified titanium dioxide.

[0030] Preparation Example 3 Preparation of antibacterial modified titanium dioxide: 72g of titanium dioxide was added to 500ml of aqueous solution containing 5g of polyethylene glycol and ultrasonically dispersed for 20min. 0.05mol / L PBS buffer was added to adjust the pH to 6. 2.5g of EDC and 1.6g of NHS were added and stirred to activate for 30min. Then 28g of polylysine hydrochloride was added, and the mixture was heated to 45℃ and reacted for 5h. The mixture was centrifuged at 5000r / min for 20min, washed 4 times with water, vacuum dried at 60℃ for 6h, and ground through a 300-mesh sieve to obtain antibacterial modified titanium dioxide.

[0031] Preparation Example 4 Preparation of modified styrene-butadiene emulsion: 100g of styrene-butadiene emulsion was added to 80g of aqueous solution containing 0.3g of sodium bicarbonate. The mixture was heated to 70℃ and stirred for 15min. At 70℃, an initiator solution containing 0.8g of ammonium persulfate and 5g of water, and a monomer solution containing 6g of hydroxyethyl acrylate and 10g of water were added dropwise simultaneously and slowly. After the addition was complete, the mixture was stirred at 75℃ for 1.5h. The temperature was then lowered to 35℃, and the pH was adjusted to 7.5 with ammonia. 0.2g of organosilicon defoamer was added, and the mixture was stirred for 15min. The mixture was then distilled under reduced pressure at 65℃ and -0.09MPa, and filtered to obtain the modified styrene-butadiene emulsion.

[0032] Preparation Example 5 Preparation of quaternary ammonium salt modified polysiloxane emulsion: Take 150g of hydroxyl polysiloxane and 80mL of isopropanol, stir evenly, heat to 60℃, add 1.5g of tetramethylammonium hydroxide, stir for 10min, add 25g of 3-chloro-2-hydroxypropyltrimethylammonium chloride, heat to 80℃, and react for 3h at a stirring speed of 600r / min. After adjusting the pH to 7.2 with glacial acetic acid, distill under reduced pressure at 70℃ and a vacuum degree of -0.08MPa to obtain quaternary ammonium salt modified polysiloxane emulsion.

[0033] Preparation Example 6 Preparation of quaternary ammonium salt modified polysiloxane emulsion: Take 160g of hydroxyl polysiloxane and 80mL of isopropanol, stir evenly and heat to 60℃, add 1.5g of tetramethylammonium hydroxide, stir for 10min, add 15g of 3-chloro-2-hydroxypropyltrimethylammonium chloride, heat to 80℃, and react for 3h at a stirring speed of 600r / min. After adjusting the pH to 7.2 with glacial acetic acid, distill under reduced pressure at 70℃ and a vacuum degree of -0.08MPa to obtain quaternary ammonium salt modified polysiloxane emulsion. Example 1

[0034] The preparation method of the photocatalytic antibacterial composition includes the following preparation steps: S1, 5.6g of the antibacterial modified titanium dioxide prepared in Preparation Example 1 is added to 76.5g of water and stirred for 30min to obtain solution A; S2, 14.8g of resin emulsion is added to 1.5g of nonylphenol polyoxyethylene ether and stirred to obtain solution B; (the resin emulsion is the modified styrene-butadiene emulsion, styrene-acrylic emulsion prepared in Preparation Example 4, and the quaternary ammonium salt modified polysiloxane emulsion prepared in Preparation Example 5, with a mass ratio of 2.5:1.5:1.2); S3, solution B obtained in step S2 is added to solution A obtained in step S1, 1.0g of fatty alcohol polyoxyethylene ether and 0.6g of film-forming aid are added and stirred (the mass ratio of film-forming aid is 3:1 of alcohol ester dodecyl and propylene glycol phenyl ether), 25% ammonia water is added dropwise to adjust the pH of the system to 8, and the product is discharged to obtain the photocatalytic antibacterial composition. Example 2

[0035] The only difference between Example 2 and Example 1 is that the resin emulsion in Example 2 is the modified styrene-butadiene emulsion and styrene-acrylic emulsion prepared in Preparation Example 4 with a mass ratio of 2:2:1.2, and the quaternary ammonium salt modified polysiloxane emulsion prepared in Preparation Example 5. Example 3

[0036] The only difference between Example 3 and Example 1 is that the resin emulsion in Example 3 is the modified styrene-butadiene emulsion and styrene-acrylic emulsion prepared in Preparation Example 4 with a mass ratio of 2.5:1.8:0.9, and the quaternary ammonium salt modified polysiloxane emulsion prepared in Preparation Example 5. Example 4

[0037] The only difference between Example 4 and Example 1 is that the antibacterial modified titanium dioxide in Example 4 is 5.6g of the antibacterial modified titanium dioxide prepared in Example 2. Example 5

[0038] The only difference between Example 5 and Example 1 is that the antibacterial modified titanium dioxide in Example 5 is the antibacterial modified titanium dioxide prepared in Example 3. Example 6

[0039] The only difference between Example 6 and Example 1 is that the resin emulsion in Example 6 is the modified styrene-butadiene emulsion and styrene-acrylic emulsion prepared in Preparation Example 4 with a mass ratio of 2.5:1.5:1.2, and the quaternary ammonium salt modified polysiloxane emulsion prepared in Preparation Example 6.

[0040] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that the resin emulsion in Comparative Example 1 is a styrene-acrylic emulsion with a mass ratio of 4:1.2, while the resin emulsion in Preparation Example 5 is a quaternary ammonium salt modified polysiloxane emulsion.

[0041] Comparative Example 2 The only difference between Comparative Example 2 and Example 1 is that the resin emulsion in Comparative Example 2 is the modified styrene-butadiene emulsion prepared in Preparation Example 4 with a mass ratio of 4:1.2 and the quaternary ammonium salt modified polysiloxane emulsion prepared in Preparation Example 5.

[0042] Comparative Example 3 The only difference between Comparative Example 3 and Example 1 is that the resin emulsion in Comparative Example 3 is the modified styrene-butadiene emulsion prepared in Preparation Example 4 with a mass ratio of 4:1.2 and the quaternary ammonium salt modified polysiloxane emulsion prepared in Preparation Example 5.

[0043] Comparative Example 4 The only difference between Comparative Example 4 and Example 1 is that the resin emulsion in Comparative Example 4 is a styrene-butadiene emulsion, a styrene-acrylic emulsion with a mass ratio of 2.5:1.5:1.2, and the quaternary ammonium salt modified polysiloxane emulsion obtained in Preparation Example 5.

[0044] Comparative Example 5 The only difference between Comparative Example 5 and Example 1 is that the resin emulsion in Comparative Example 5 is the modified styrene-butadiene emulsion, styrene-acrylic emulsion, and hydroxyl polysiloxane emulsion prepared in Preparation Example 4 with a mass ratio of 2.5:1.5:1.2.

[0045] Comparative Example 6 The only difference between Comparative Example 6 and Example 1 is that the 5.6g of antibacterial modified titanium dioxide prepared in Example 1 in Comparative Example 6 was replaced with 5.6g of titanium dioxide.

[0046] The photocatalytic antibacterial compositions prepared in each embodiment and comparative example were used at 35 g / m². 2 The coating was sprayed onto a polystyrene prism plate sample. The sample was then placed in an oven and the oven temperature was set to 60°C to cure the coating, resulting in the coated samples of the catalytic antibacterial compositions of each embodiment and comparative example.

[0047] 1. The prism plate samples prepared in each embodiment and comparative example were subjected to a xenon lamp accelerated aging test for 1000 hours according to GB / T 1865-2009 standard. At the 1000-hour aging time point, the cross-cut adhesion test was performed on each prism plate sample according to GB / T 9286-2021 "Paints and Varnishes - Cross-cut Adhesion Test". 2. The antibacterial properties of each coating sample were tested in accordance with GB / T 23763-2009 "Evaluation of Antibacterial Properties of Photocatalytic Antibacterial Materials and Products". The strain used for the antibacterial test was Staphylococcus albus 8032. The test results are recorded in Table 1 below.

[0048] Table 1 Sample number Adhesion grade after 1000 hours Initial antibacterial rate (%) Antibacterial rate (%) after 1000h Example 1 0 99.98 99.88 Example 2 0 97.51 95.24 Example 3 2 94.79 88.49 Example 4 1 97.78 96.36 Example 5 1 95.12 91.34 Example 6 2 96.24 90.52 Comparative Example 1 4 98.79 90.56 Comparative Example 2 5 (Large-area peeling) 97.58 92.17 Comparative Example 3 4 87.78 77.15 Comparative Example 4 3 95.89 87.98 Comparative Example 5 3 89.28 81.56 Comparative Example 6 2 75.98 68.21 like Figure 1 The photocatalytic antibacterial composition prepared in Example 1 of this application, after standing for 48 hours, still showed no obvious precipitate at the bottom, remaining a white and homogeneous dispersion. Figure 2 To obtain 35 μL of the photocatalytic antibacterial agent prepared in Example 1 of this application, mix it with 35 μL of Rhodamine B and irradiate it with a 30W UV lamp for 5 min. Comparison of images before (top) and after (bottom) UV lamp irradiation. Figure 3 To obtain a comparison image, take 0.25 ml of antibacterial solution, apply it to a 50×50 mm prism plate, dry it for 10 minutes, and then irradiate it with a 25W panel lamp for 10 minutes. The image shows the comparison before (left) and after (right) irradiation.

[0049] Combined with Examples 1-3, Example 6, and Comparative Examples 1-5, it can be seen that the test data results of the prism plate sample of Example 1 after 1000 hours of aging test, including adhesion, long-term antibacterial performance, and resistance to photodegradation, are all better than those of Examples 2-3, Example 6, and the comparative examples. This may be because the antibacterial modified titanium dioxide of this application has an antibacterial synergistic effect with styrene-butadiene emulsion, styrene-acrylic emulsion, and quaternary ammonium salt modified polysiloxane emulsion, constructing a highly efficient photocatalytic antibacterial system, improving the antibacterial long-term effect and stability of the composition, preventing uneven dispersion of antibacterial components, rapid efficacy decay, and reduction of photocatalytic performance; the modified styrene-butadiene emulsion interacts with styrene-acrylic emulsion and quaternary ammonium salt modified polysiloxane emulsion to jointly achieve stable coating film formation, fix antibacterial components, and achieve long-term antibacterial effect.

[0050] Based on Examples 1, 4-5, and Comparative Example 6, the prism plate sample of Example 1, after a 1000-hour aging test, showed better results in adhesion, long-lasting antibacterial performance, and resistance to photodegradation than Examples 2-3, 6, and the comparative example. This may be because polylysine antibacterial salt was introduced into the titanium dioxide surface treatment. Polylysine antibacterial salt has excellent biocompatibility and antibacterial activity, and has specific adsorption capacity for Gram-positive bacteria such as Staphylococcus aureus and Gram-negative bacteria such as Escherichia coli, achieving targeted sterilization. It also shortens the diffusion distance of reactive oxygen species generated by photocatalysis, significantly improving sterilization efficiency and providing a structural basis for long-lasting antibacterial effects. Furthermore, it interacts with the modified styrene-butadiene emulsion, firmly fixing the antibacterial modified titanium dioxide onto the emulsion molecular chain, effectively inhibiting its aggregation and migration, ensuring uniform exposure of antibacterial sites and photocatalytic active sites, and strengthening the binding stability with the resin system. This prevents the loss of antibacterial components during long-term use and provides structural support for long-lasting antibacterial effects.

[0051] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for preparing photocatalytic antibacterial modified titanium dioxide, characterized in that, The process includes the following steps: adding titanium dioxide to an aqueous solution of polyethylene glycol and ultrasonically dispersing for 15-20 min, adjusting the pH to 5-6, adding EDC / NHS, and stirring to activate for 20-30 min; then adding polylysine antibacterial salt and heating to 45-50℃ for 4-5 h to obtain antibacterial modified titanium dioxide; the mass ratio of titanium dioxide to polylysine antibacterial salt is (3-5):

1.

2. An antibacterial composition, characterized in that, The composition comprises the following components by weight percentage: 5.6-6.1% antibacterial modified titanium dioxide, 13.9-24.6% resin emulsion, 1.4-1.7% dispersant, 0.8-1.0% wetting agent, 0.5-0.8% film-forming aid, and 65.8-77.8% water; wherein the resin emulsion comprises modified styrene-butadiene emulsion, styrene-acrylic emulsion, and quaternary ammonium salt modified polysiloxane emulsion; and the antibacterial modified titanium dioxide is the antibacterial modified titanium dioxide obtained by the preparation method according to any one of claims 1-2.

3. The antibacterial composition according to claim 2, characterized in that, The method for preparing the modified styrene-butadiene emulsion includes: adding the styrene-butadiene emulsion to an aqueous solution containing sodium bicarbonate, heating to 65-75℃ and stirring for 10-15 min, adding ammonium persulfate and hydroxyethyl acrylate, stirring at 75-80℃ for 1-2 h, adjusting the pH to 6.5-7.5, adding an organosilicon defoamer, and stirring for 10-15 min to obtain the modified styrene-butadiene emulsion.

4. The antibacterial composition according to claim 2, characterized in that, The mass ratio of the modified styrene-butadiene emulsion, styrene-acrylic emulsion, and quaternary ammonium salt modified polysiloxane emulsion is (2.4-2.8):(1.5-1.9):(1.2-1.6).

5. The antibacterial composition according to claim 2, characterized in that, The dispersant is nonylphenol polyoxyethylene ether, and the wetting agent is fatty alcohol polyoxyethylene ether.

6. A method for preparing the antibacterial composition according to any one of claims 2-5, characterized in that, The preparation steps include the following: S1. Take antibacterial modified titanium dioxide and add it to water and stir for 20-30 minutes to obtain solution A; S2. Take the resin emulsion, add the dispersant, and stir to mix to obtain solution B; S3. Add the solution B obtained in step S2 to the solution A obtained in step S1, add wetting agent and film-forming aid, stir and mix, adjust the pH value of the system to 7-8, discharge the material, and obtain the antibacterial composition.

7. The use of the antibacterial composition according to any one of claims 2-5, characterized in that, Application of antibacterial compositions in prism plates.

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