Antibacterial composition and preparation method thereof

Abstract

The invention relates to the field of functional material preparation, and discloses an antibacterial composition and a preparation method thereof, the composition comprises an interface hydrophobically modified porous inorganic carrier, an organic sulfuryl antibacterial agent, elemental iodine and an optional electron donor additive. The preparation method comprises the following steps: adding the raw materials into mixing equipment and uniformly mixing; raising the temperature to T1, and stirring and reacting at a constant temperature under a vacuum condition, so that the molten organic sulfuryl antibacterial agent is filled into a carrier pore channel; reducing the temperature of the system to a temperature T2, adding elemental iodine, sealing the reaction kettle, and carrying out a heat preservation reaction under a stirring condition; and cooling and crushing the reaction product. By improving the wettability of a carrier interface, overcoming the filling resistance of an organic melt and utilizing dual mechanisms of inorganic framework confinement and internal chemical complexation, the heat-resistant stability and the processing dispersibility of iodine are remarkably improved, and the material is endowed with excellent washing resistance and long-acting slow release performance; the technical problem that a traditional iodine-based antibacterial agent is prone to sublimation and loss is solved.

Description

Technical Field

[0001] This invention relates to the field of functional materials preparation technology, specifically to an antibacterial composition and its preparation method. Background Technology

[0002] Elemental iodine possesses broad-spectrum and highly effective bactericidal and antiviral properties, making it widely used in medical and water treatment fields. However, elemental iodine has a high saturated vapor pressure, is highly sublimable, and is chemically reactive, resulting in poor thermal stability and making it difficult to directly apply to the modification of polymer materials such as polypropylene and nylon that require high-temperature melting processing. Directly adding elemental iodine not only generates large amounts of colored fumes during processing, corroding equipment and polluting the environment, but also leads to low residual levels of the effective components in the final product, and it is prone to rapid release during use, lacking long-lasting antibacterial capabilities.

[0003] To address these issues, existing technologies often employ porous inorganic materials (such as zeolites, silica gel, and mesoporous molecular sieves) as supports for the physical adsorption and loading of iodine. While the porous structure of these supports can limit the thermal motion of iodine molecules to some extent, physical adsorption alone is insufficient to effectively bind iodine molecules during high-temperature processing or in aqueous environments, leading to rapid desorption or sublimation of iodine. Therefore, researchers have attempted to introduce organic complexing agents (such as polyvinylpyrrolidone) into the pores of the support to anchor iodine molecules.

[0004] However, conventional porous inorganic carriers typically have a large number of hydroxyl groups distributed on their pore walls, exhibiting strong hydrophilicity, while many organic complex matrices or stabilizers with excellent heat resistance are usually hydrophobic and have high melt viscosity. During the preparation process, due to the significant interfacial energy difference between the inorganic carrier pore walls and the hydrophobic organic melt, the organic melt struggles to overcome capillary resistance and penetrate deep into the micropores, often only adhering to the outer surface of the carrier particles or blocking the pore openings. This results in the ineffective utilization of the large pore volume within the carrier, preventing the subsequently loaded iodine molecules from entering the pores to form a stable, confined complex structure with the organic matrix, and causing them to exist mostly in a free or surface-crystalline state. This surface-enriched distribution makes the antibacterial agent prone to agglomeration during subsequent polymer melt spinning or extrusion, and the surface iodine rapidly sublimates at high temperatures, causing foaming and breakage of the matrix material, severely affecting processing performance. Furthermore, during the washing process of end products (such as fiber fabrics), the active ingredients on the surface are easily washed away by water, failing to meet durability requirements. Therefore, how to overcome the interfacial wetting barrier between inorganic carriers and organic matrices and achieve deep loading and stable locking of active components is a technical problem that urgently needs to be solved in the field of iodine-based antibacterial materials. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an antibacterial composition and its preparation method, which solves the problems in existing inorganic carrier-loaded iodine technology for antibacterial compositions, where the difference in interfacial energy of the pore walls prevents the hydrophobic organic matrix from being deeply filled, resulting in poor heat processing resistance, easy sublimation of active ingredients, and insufficient washability of the antibacterial agent.

[0006] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides an antibacterial composition, which adopts the following technical solution: An antibacterial composition comprising the following components in parts by weight: 55-72 parts of an interface-modified porous inorganic carrier; 15-25 parts of an organic sulfone-based antibacterial agent; 5-15 parts of elemental iodine; and 0-5 parts of an electron donor auxiliaries.

[0007] By employing the above technical solution, this invention utilizes an interface-modified porous inorganic carrier as a framework, effectively reducing the polarity of the inorganic pore wall surface and improving its wetting properties with the hydrophobic organic sulfone-based antibacterial agent melt. During the preparation process, the interface-modified layer reduces the capillary resistance of the melt entering the micropores, enabling the organic sulfone-based antibacterial agent to deeply fill the micropores or mesopores of the carrier. The organic sulfone-based antibacterial agent entering the pores acts as a solvation matrix, utilizing the electron-withdrawing or electron-donating properties of the sulfone structure to undergo charge-transfer complexation reactions with the infiltrated elemental iodine, forming a stable chemically anchored structure. The rigid framework of the inorganic carrier provides physical spatial confinement, blocking the direct transfer of external heat; the organic matrix filling the pores increases the tortuosity of the diffusion path of iodine molecules and raises the activation energy required for iodine molecule desorption. This dual mechanism of physical confinement and chemical anchoring significantly increases the initial sublimation temperature of elemental iodine, inhibits its volatilization during high-temperature processing, and utilizes the hydrophobic properties of the organic matrix to delay the contact and dissolution of internal active ingredients by water molecules, thus achieving stable and long-term release of iodine in an aqueous environment.

[0008] Preferably, the interface hydrophobically modified porous inorganic carrier is composed of a porous inorganic carrier and an interface modifier, and the weight ratio of the porous inorganic carrier to the interface modifier is 100:(2-10).

[0009] By adopting the above technical solution, a specific ratio of interface modifier can form a monolayer or thin layer covering the pore wall of the carrier, which not only achieves the oleophilic transformation of the surface properties, but also avoids the blockage of the pore opening by excessive modifier, and retains sufficient pore volume for subsequent active component filling.

[0010] Preferably, the porous inorganic carrier is ZSM-5 zeolite, SBA-15 mesoporous silica, or Y-type zeolite; the interface modifier is zinc stearate or polypropylene wax; and the organic sulfone-based antibacterial agent is 4,4'-dichlorodiphenyl sulfone or bisphenol S.

[0011] By employing the above technical solutions, the aforementioned porous supports possess regular pore structures and suitable pore sizes, enabling them to accommodate larger organic sulfone-based matrices. Zinc stearate or polypropylene wax exhibits low viscosity and good lubricity at high temperatures, facilitating melt flow. 4,4'-dichlorodiphenyl sulfone or bisphenol S possesses high heat distortion temperatures and rigid benzene ring structures, significantly enhancing the thermal stability of iodine molecules when used as a matrix.

[0012] Preferably, the electron donor is polyvinylpyrrolidone, and the dosage is 2-5 parts.

[0013] By adopting the above technical solution, polyvinylpyrrolidone, as an auxiliary complexing agent, can form additional complexing centers with iodine molecules, further stabilizing the dispersed iodine and reducing the proportion of free iodine.

[0014] Preferably, the interface hydrophobic modified porous inorganic carrier is prepared by dehydrating the porous inorganic carrier, mixing it with an interface modifier, and stirring it under negative pressure conditions of 130-160℃ and -0.01MPa to -0.05MPa.

[0015] By adopting the above technical solution, the high temperature and negative pressure conditions promote the melting and liquefaction of the interface modifier and displace the pore gas, so that it spreads evenly on the surface of the carrier pore wall and forms a stable hydrophobic modification layer.

[0016] Secondly, the present invention provides a method for preparing an antibacterial composition, employing the following technical solution: A method for preparing an antibacterial composition includes the following steps: Deep filling: The interface hydrophobically modified porous inorganic carrier, organic sulfone-based antibacterial agent and optional electron donor auxiliary agent are added to the mixing equipment and mixed evenly; Melt anchoring: The mixture system formed in the deep filling step is heated to temperature T1 and stirred under vacuum conditions to allow the molten organic sulfone-based antibacterial agent to fill into the carrier pores; Gas-phase lock-in: The temperature of the mixture is lowered to temperature T2, elemental iodine is added, the reaction vessel is sealed, and the reaction is carried out under stirring and heat preservation conditions; Post-processing: The reaction product is cooled and pulverized to obtain the antibacterial composition.

[0017] By adopting the above technical solution, this preparation method constructs a stepwise gradient assembly mechanism from interface modification to melt filling and then to gas phase locking. The specific mechanism of action is as follows: First, in the melt anchoring stage, high temperature is used to bring the organic sulfone-based antibacterial agent to a molten and flowing state, while a high vacuum environment eliminates gas resistance within the pores. At this point, the pre-existing hydrophobic modified layer on the pore walls of the carrier plays a crucial role, eliminating the inorganic-organic interfacial tension barrier, inducing the hydrophobic melt to overcome pore resistance, deeply wetting and filling the micropores or mesopores of the carrier, thereby constructing continuous organic adsorption sites within the carrier.

[0018] Secondly, in the gas-phase locking stage, the system temperature is lowered to T2. This temperature range is typically set above the sublimation temperature of iodine but below the melting point or flow temperature of the organic sulfone component. Under these conditions, elemental iodine sublimates into gaseous molecules with extremely high permeability. Driven by the concentration gradient, the gaseous iodine molecules rapidly diffuse into the carrier pores. Since the pores are pre-filled with a complexing organic sulfone matrix, the entering iodine molecules are rapidly captured and undergo a chemical complexation reaction, thus being firmly locked deep within the pores.

[0019] This process avoids the competitive adsorption problem caused by simultaneous heating of components in traditional mixing processes, preventing the enrichment and recrystallization of elemental iodine on the outer surface of the carrier. In the product, iodine is mainly embedded in the pores in an amorphous form, and is externally coated with a hydrophobic modification layer and an inorganic framework. This structure effectively resists external mechanical friction and water erosion, improving the material's washability.

[0020] Preferably, the temperature T1 is 170-260℃, the vacuum condition is -0.06MPa to -0.09MPa, and the reaction time is 40-90 minutes.

[0021] By adopting the above technical solution, the higher temperature T1 ensures that the organic sulfone-based antibacterial agent is fully melted and the viscosity is reduced, the high vacuum provides a strong pressure difference driving force, and the long-term stirring reaction ensures the thermodynamic balance of the filling process, thereby maximizing the utilization rate of the pore volume.

[0022] Preferably, the temperature T2 is 80-110℃, and the heat preservation reaction time is 1.0-3.0 hours.

[0023] By adopting the above technical solution, controlling the temperature T2 ensures that iodine has sufficient vapor pressure to maintain the diffusion rate, while also preventing secondary flow or excessive volatilization of the filled organic matrix, thus ensuring the stable progress of the gas phase loading process.

[0024] Preferably, prior to the deep filling, the method further includes a step of preparing an interface-modified porous inorganic support: (1) The porous inorganic carrier is subjected to heating and degassing treatment; (2) Mix the treated carrier with the interface modifier; (3) The mixture is heated to temperature T0 and stirred under negative pressure. After cooling, the hydrophobic modified porous inorganic carrier is obtained.

[0025] By employing the above technical solution, the pre-degassing treatment removes adsorbed water from the pores, preventing moisture from hindering the subsequent entry of organic matter. The independent interface modification step ensures the complete construction of the hydrophobic layer on the pore walls, laying the interfacial foundation for the subsequent introduction of hydrophobic functional components.

[0026] Preferably, the temperature T0 is 130-160℃, and the negative pressure condition is -0.01MPa to -0.05MPa.

[0027] By adopting the above technical solution, the process parameters ensure that the interface modifier is in a molten, low-viscosity state and can enter the pore area under negative pressure assistance to form an effective hydrophobic barrier.

[0028] This invention provides an antibacterial composition and its preparation method. It has the following beneficial effects: 1. This invention overcomes the wetting barrier between the hydrophilic inorganic framework and the hydrophobic organic sulfone-based melt by modifying the pore walls of the porous inorganic carrier with hydrophobic interface, enabling the high-viscosity organic matrix to deeply fill the micropores. This effectively utilizes the physical thermal barrier and spatial confinement effect of the inorganic framework, solving the weight loss and foaming problems caused by the easy volatilization of iodine molecules during high-temperature melting and processing. At the same time, the oleophilic modification of the carrier surface reduces the interfacial energy between the inorganic filler and the polymer matrix, eliminating the agglomeration phenomenon under high filling amount, and ensuring the monodispersity and processing stability of the composition in the matrix resin.

[0029] 2. This invention avoids the disordered accumulation caused by competitive adsorption of components in traditional mixing processes by using a stepwise gradient process from interface modification to melt filling and then to gas phase locking. This forces iodine molecules to diffuse into the confined channels pre-filled with sulfone-based media, thereby inhibiting the surface self-aggregation and crystallization of iodine at the microscopic level, promoting its stable existence in an amorphous state. This effectively resists external mechanical friction and water erosion, reduces the washing loss rate of active ingredients, and endows the final product with excellent wash resistance and long-lasting antibacterial ability.

[0030] 3. This invention uses an organic sulfone-based compound as a specific solubilizing matrix to construct a stable charge-transfer complex system with iodine molecules within the pores of a porous carrier. This chemical anchoring effect is used to raise the escape energy barrier of iodine molecules, thereby effectively solving the technical defects of elemental iodine being extremely prone to sublimation and exhibiting burst release in the aqueous phase. At the same time, combined with the diffusion hindrance effect formed by the hydrophobic matrix within the pores, zero-order or near-zero-order stable release of iodine is achieved during storage and use, extending the service life of the antibacterial material. Attached Figure Description

[0031] Figure 1 This is a flowchart of the preparation process of the present invention. Detailed Implementation

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Please see the appendix Figure 1 : Preparation Example 1: This preparation example provides a porous inorganic support intermediate with hydrophobic interface modification, including the following steps: (1) 60 parts by weight of porous carrier A (ZSM-5 zeolite, particle size 2.0 μm) were placed in a vacuum drying oven and degassed at 250 °C and -0.09 MPa for 4.0 hours, and then cooled to 120 °C for later use. (2) Transfer the pretreated porous carrier A to a high-speed mixer and add 3 parts by weight of interface modifier A (zinc stearate, melting point 120°C). (3) Heat the mixer to 135°C and stir for 30 minutes at 1000 rpm and a slight negative pressure (-0.02 MPa) to fully wet and coat the inner wall of the micropores of the carrier with the molten interface modifier. After cooling, the hydrophobic modified carrier intermediate P1 is obtained.

[0034] Preparation Example 2: This preparation example provides a porous inorganic support intermediate with hydrophobic interface modification, including the following steps: (1) Place 70 parts by weight of porous carrier B (SBA-15 mesoporous silica, particle size 5.0 μm) in a vacuum drying oven and degas it for 3.0 hours at 200℃ and -0.09 MPa, and then cool it to 100℃ for later use. (2) Transfer the pretreated porous carrier B to a high-speed mixer and add 2 parts by weight of interface modifier A (zinc stearate). (3) Heat the mixer to 130°C and stir for 20 minutes at 500 rpm and a slight negative pressure (-0.01 MPa). After cooling, the hydrophobic modified carrier intermediate P2 is obtained.

[0035] Preparation Example 3: This preparation example provides a porous inorganic support intermediate with hydrophobic interface modification, including the following steps: (1) Place 50 parts by weight of porous carrier A (ZSM-5 zeolite) in a vacuum drying oven and degas it at 300℃ and -0.09MPa for 5.0 hours, then cool it to 120℃ for later use. (2) Transfer the pretreated porous carrier A to a high-speed mixer and add 5 parts by weight of interface modifier B (polypropylene wax, softening point 150℃). (3) Heat the mixer to 160°C and stir for 40 minutes at 1500 rpm and a slight negative pressure (-0.05 MPa). After cooling, the hydrophobic modified carrier intermediate P3 is obtained.

[0036] Example 1: This embodiment provides a highly heat-resistant iodine-sulfone-based antibacterial composition based on interface gradient modification, the raw material composition of which, by weight, is as follows: The hydrophobic modified carrier intermediate P1 obtained in Preparation Example 1 contained 63 parts of ZSM-5 zeolite (60 parts and zinc stearate, 3 parts), 20 parts of organic sulfone antibacterial agent A (4,4'-dichlorodiphenyl sulfone), 10 parts of elemental iodine, and 2 parts of electron donor auxiliaries (PVP K30).

[0037] The preparation method of this embodiment includes the following steps: S1, Deep Fill: 63 parts by weight of the hydrophobic modified carrier intermediate P1 obtained in Preparation Example 1 were placed into a high-speed mixer equipped with heating and vacuum functions, and 20 parts by weight of organic sulfone antibacterial agent A and 2 parts by weight of PVP were added.

[0038] S2, Melt anchoring: Turn on the stirrer (1200 rpm) and heat the mixture to 180°C. Maintain the temperature and stir the mixture under a vacuum of -0.08 MPa for 60 minutes. During this process, the molten organic sulfone-based antibacterial agent deeply fills the pores of the carrier by wetting the pre-formed hydrophobic layer on the inner wall of the pores.

[0039] S3, Gas Phase Locking: Stop heating and lower the system temperature to 95℃ (T3), then add 10 parts by weight of elemental iodine. Seal the reactor and maintain the temperature for 2.0 hours with low-speed stirring (300 rpm) to allow the sublimated iodine molecules to permeate into the pores and form a complex structure with the sulfone matrix.

[0040] S4. Post-processing: Cooling water is introduced to quickly cool the material to below 30°C. The resulting solid product is then pulverized by an air jet mill and sieved through a 500-mesh screen to obtain a grayish-purple high heat-resistant antibacterial compound powder.

[0041] Example 2: This embodiment provides a high heat-resistant iodine-sulfone-based antibacterial composition based on interface gradient modification. The raw material composition by weight is as follows: 72 parts of hydrophobic modified carrier intermediate P2 (containing 70 parts of SBA-15 mesoporous silica and 2 parts of zinc stearate) obtained in Preparation Example 2, 15 parts of organic sulfone-based antibacterial agent A (4,4'-dichlorodiphenyl sulfone), and 5 parts of elemental iodine.

[0042] The preparation method of this embodiment includes the following steps: S1, Deep Fill: 72 parts by weight of the hydrophobic modified carrier intermediate P2 obtained in Preparation Example 2 were put into a mixer and 15 parts by weight of organic sulfone-based antibacterial agent A were added.

[0043] S2, Melt anchoring: Turn on the stirrer (800 rpm) and heat the mixture to 170°C. Maintain the temperature and stir the mixture under a vacuum of -0.06 MPa for 40 minutes to allow the molten sulfone-based component to fill the pores of the support.

[0044] S3, Gas Phase Locking: Stop heating and lower the system temperature to 80°C (T3). Add 5 parts by weight of elemental iodine. Seal the reactor and maintain the temperature for 1.0 hour with low stirring (200 rpm).

[0045] S4. Post-processing: The product is rapidly cooled to room temperature and then subjected to airflow pulverization and sieving to obtain a light purple antibacterial composition powder.

[0046] Example 3: This embodiment provides a high heat-resistant iodine-sulfone-based antibacterial composition based on interface gradient modification. The raw material composition by weight is as follows: 55 parts of hydrophobic modified carrier intermediate P3 obtained in Preparation Example 3 (the carrier in Preparation Example 3 should be adjusted to a high-porosity Y-type zeolite, containing 50 parts of zeolite and 5 parts of polypropylene wax), 25 parts of organic sulfone-based antibacterial agent B (bisphenol S), 15 parts of elemental iodine, and 5 parts of electron donor auxiliary agent (PVP K30).

[0047] The preparation method of this embodiment includes the following steps: S1, Deep Fill: 55 parts by weight of the hydrophobic modified support intermediate P3 obtained in Example 3 (the support is a high-porosity Y-type zeolite with a pore volume > 0.6 cm³) were used. 3 / g) is put into a high-speed mixer with high temperature heating function, and 25 parts by weight of organic sulfone antibacterial agent B and 5 parts by weight of PVP are added.

[0048] S2, Melt anchoring: Turn on the stirrer (2000 rpm) and heat the mixture to 260℃ (note: above the melting point of bisphenol S, and Y-type zeolite has excellent thermal stability). Maintain the temperature and stir the mixture under a high vacuum of -0.09 MPa for 90 minutes. Under these high temperature and high vacuum conditions, the high-viscosity bisphenol S melt, aided by the hydrophobic PP wax layer, fully penetrates deep into the pores of the macroporous zeolite.

[0049] S3, Gas Phase Locking: Stop heating and lower the system temperature to 110℃ (T3), then add 15 parts by weight of elemental iodine. Seal the reactor and maintain the temperature for 3.0 hours with low-speed stirring (500 rpm) to ensure that the high concentration of iodine molecules diffuses and complexes fully.

[0050] S4. Post-processing: The material is cooled and solidified by rapidly introducing a refrigerant. The resulting dark brown solid product is then pulverized and sieved by airflow to obtain a high-load, high-heat-resistant antibacterial composition powder.

[0051] Comparative Example 1: This comparative example provides an antibacterial composition that differs from Example 1 in that the interface modification step and interface modifier A (zinc stearate) in Preparation Example 1 are omitted, while all other steps are the same.

[0052] Comparative Example 2: This comparative example provides an antibacterial composition that differs from Example 1 in that it employs an integrated mixing process instead of a stepwise gradient filling process; all other aspects are the same.

[0053] Comparative Example 3: This comparative example provides an antibacterial composition that differs from Example 1 in that it does not contain organic sulfone-based antibacterial agent A, while all other aspects are the same.

[0054] Test Example 1: This test case aims to compare the performance differences between the products obtained in Example 1 and Comparative Example 1, and to verify the technical effect of the hydrophobic modification step of the porous carrier channel inner wall interface in constructing a heat-resistant system and improving processing rheology.

[0055] Experimental steps: Thermogravimetric analysis was performed using a TGA instrument. 10.0 mg of each powder sample from Example 1 and Comparative Example 1 were placed in an alumina crucible. The temperature was increased from room temperature to 400 °C at a rate of 20 °C / min under a nitrogen atmosphere, and the percentage of mass loss at 300 °C and 350 °C was recorded.

[0056] The filter pressure value (FPV) test is conducted according to ISO 23900-5 standard. The powder to be tested is mixed with polypropylene resin to prepare a masterbatch with a content of 10wt%. The masterbatch is melt-extruded using a single screw extruder equipped with a 325-mesh filter screen. The pressure change of the melt flowing through the filter screen is recorded and the FPV value is calculated.

[0057] The effective iodine retention rate was determined by treating the sample in a muffle furnace at 300℃ for 30 minutes, cooling it, and then extracting it with anhydrous ethanol using a Soxhlet extract for 4 hours. The residual iodine content of the extract was determined by titration with sodium thiosulfate, and the ratio of the residual iodine content to the initial iodine content was calculated (see Table 1 for data details).

[0058] Experimental data: Table 1

[0059] Note: The thermal weight loss rate data has been adjusted to exclude the baseline value of water adsorbed by the carrier itself.

[0060] Test Summary: Table 1 shows that the thermal weight loss rate and filtration pressure value of Example 1 are lower than those of Comparative Example 1, while the iodine retention rate is higher. Comparative Example 1 did not undergo interface hydrophobic modification; the hydrophilicity of the porous carrier pore walls and the hydrophobic dichlorodiphenyl sulfone melt created an interfacial tension difference, hindering the melt from entering the micropores. The organic components mainly adhered to the outer surface of the carrier, lacking the spatial confinement protection of the pore structure. The complex structure of iodine molecules and sulfone groups easily dissociated and volatilized upon heating, resulting in significant mass loss at high temperatures and a low iodine retention rate. During processing, the surface polarity of the unmodified inorganic carrier was incompatible with the polypropylene matrix, and the accumulated organic matter on the surface easily caused agglomeration, leading to an increase in filtration pressure.

[0061] Example 1 utilizes zinc stearate to modify the pore walls, reducing the interfacial energy between the organic melt and the pore walls, promoting the wetting and filling of dichlorodiphenyl sulfone melt into the micropores. Iodine molecules, after entering the pores, are anchored by the organic matrix. The physical barrier of the inorganic framework and internal chemical complexation jointly limit the dispersion and escape of iodine, reducing mass loss at high temperatures and improving iodine retention. The aliphatic structure formed by the interface modifier on the outer layer of the carrier particles improves the compatibility between the inorganic filler and the polypropylene matrix, reduces agglomeration during melt processing, and lowers the filtration pressure. Experimental results show that the hydrophobic modification of the pore inner walls facilitates deep loading of organic components and improves the material's thermal stability and processing dispersibility.

[0062] Test Example 2: Experimental steps: The powders prepared in Example 1 and Comparative Example 2 were mixed with polypropylene chips at an addition rate of 3 wt%, respectively, and then melt-spun into polypropylene fibers, which were then woven into standard fabric samples.

[0063] The crystal structure of the powder sample was analyzed by X-ray diffraction (XRD), with a scanning range of 2θ from 5° to 40°. The intensity of the iodine characteristic peak was observed and recorded.

[0064] The wash resistance test was conducted according to AATCC 61-2A standard, with the fabric sample subjected to 20 cycles of washing at a temperature of 49°C and mechanical agitation with steel balls.

[0065] The iodine content and antibacterial rate of the fabric samples before and after washing were determined. The iodine content was determined by combustion-ion chromatography (IC). The antibacterial rate was tested according to JIS L 1902 standard, and the test species was Staphylococcus aureus. The washing loss rate was calculated based on the test results (see Table 2 for data details).

[0066] Table 2

[0067] Note: The relative intensities of the characteristic peaks of iodine in XRD are normalized based on the intensity of the main peak of pure iodine.

[0068] Test Summary: Table 2 shows that the XRD characteristic peak intensity of iodine in Comparative Example 2 sample is relatively high, indicating that iodine mainly exists in the form of free crystals. In the one-pot mixing process, all components are heated simultaneously, and the interface modifier and sulfone-based agent compete for adsorption on the support surface, failing to form an ordered pore-filling layer. After sublimation, iodine has difficulty entering the pores and effectively binding with the sulfone groups, and recrystallizes on the support and mixture surface after cooling. The characteristic peak intensity of iodine in Example 1 sample is low, indicating that iodine is mainly in an amorphous or dispersed state. The stepwise process first modifies the pore walls hydrophobically, which facilitates the wetting and filling of the pores by the sulfone-based melt. Subsequently, the introduced iodine molecules enter the pores and complex with the sulfone groups within the confined space, inhibiting the crystallization behavior of iodine.

[0069] The wash resistance test results showed that Comparative Example 2 had a higher iodine loss rate and a decreased antibacterial rate after washing. The free iodine distributed on the carrier surface had weak binding force with the carrier and was easily detached under mechanical washing and water flow. Example 1 showed a lower iodine loss rate and maintained a high antibacterial rate even after multiple washes. This is because the iodine was loaded deep into the carrier pores, and the external hydrophobic modification layer and inorganic framework structure blocked the dissolving effect of water molecules. The experiments show that the stepwise preparation process helps to construct a stable complex structure within the pores, improving the wash resistance and long-term antibacterial effect of the material.

[0070] Test Example 3: Experimental steps: The thermal escape behavior of the powder was analyzed using thermogravimetric-mass spectrometry (TG-MS). 15.0 mg of each of the powders from Example 1 and Comparative Example 3 were weighed and heated to 300 °C at a rate of 10 °C / min under a helium atmosphere. The ion current intensities at mass-to-charge ratios m / z=127 and 254 were monitored, and the iodine escape initiation temperature and peak temperature were recorded.

[0071] The sustained-release performance was tested using the static immersion method. 1.0 g of each powder was weighed and placed in an Erlenmeyer flask containing 100 mL of deionized water, and the flask was shaken at a constant temperature of 25 °C. The supernatant was collected at 1 hour, 24 hours, 72 hours, and 168 hours, and the iodine concentration was determined using a UV-Vis spectrophotometer to calculate the cumulative release (details are shown in Table 3).

[0072] Table 3

[0073] Test Summary: Table 3 shows that the initial iodine release temperature of Comparative Example 3 was 95℃, and the peak temperature was 132℃. This comparative example did not contain any organic sulfone components; the iodine molecules were mainly physically adsorbed onto the pore walls of the hydrophobic modified carrier, resulting in weak binding forces. Upon heating, the iodine easily desorbed and sublimated. In the aqueous phase release test, Comparative Example 3 showed a high release rate within 1 hour, which leveled off after 24 hours, indicating that iodine molecules diffused rapidly into the water under the influence of concentration gradients and lacked long-term sustained-release capability.

[0074] The initial iodine release temperature in Example 1 was 215°C, and the peak temperature was 288°C. In Example 1, a dichlorodiphenyl sulfone matrix was filled into the pores. After iodine molecules entered the pores, they underwent charge-transfer complexation with the sulfone groups. The chemical interaction strength was higher than that of physical adsorption, which restricted the thermal motion of iodine molecules. At the same time, the organic matrix filling in the pores increased the diffusion resistance of iodine molecules. Aqueous phase release tests showed that the iodine release rate of Example 1 was lower, and the cumulative release amount after 168 hours was lower than that of Comparative Example 3. The hydrophobic modification of the pore walls and the sulfone matrix hindered the entry of water molecules into the pores, reducing the iodine dissolution rate. The experimental results indicate that the organic sulfone matrix has an anchoring effect on iodine molecules, inhibiting the sublimation of iodine and its rapid release in the aqueous phase.

Claims

1. An antibacterial composition, characterized in that, The components include the following parts by weight: 55-72 parts of porous inorganic carrier with hydrophobic interface modification; 15-25 parts of organic sulfone-based antibacterial agent; 5-15 parts of elemental iodine; 0-5 parts of electronic donor additive.

2. The antibacterial composition according to claim 1, characterized in that, The interface hydrophobic modified porous inorganic carrier is composed of a porous inorganic carrier and an interface modifier, and the weight ratio of the porous inorganic carrier to the interface modifier is 100:(2-10).

3. The antibacterial composition according to claim 2, characterized in that, The porous inorganic carrier is ZSM-5 zeolite, SBA-15 mesoporous silica, or Y-type zeolite; the interface modifier is zinc stearate or polypropylene wax; and the organic sulfone-based antibacterial agent is 4,4'-dichlorodiphenyl sulfone or bisphenol S.

4. The antibacterial composition according to claim 1, characterized in that, The electron donor additive is polyvinylpyrrolidone, preferably 2-5 parts.

5. The antibacterial composition according to claim 1, characterized in that, The hydrophobic modified porous inorganic carrier is prepared by dehydrating the porous inorganic carrier, mixing it with an interface modifier, and stirring it under negative pressure conditions of 130-160℃ and -0.01MPa to -0.05MPa.

6. A method for preparing an antibacterial composition, applied to an antibacterial composition as described in any one of claims 1-5, characterized in that, Includes the following steps: Deep filling: The interface hydrophobically modified porous inorganic carrier, organic sulfone-based antibacterial agent and optional electron donor auxiliary agent are added to the mixing equipment and mixed evenly; Melt anchoring: The mixture system formed in the deep filling step is heated to temperature T1 and stirred under vacuum conditions to allow the molten organic sulfone-based antibacterial agent to fill into the carrier pores; Gas-phase lock-in: The temperature of the mixture is lowered to temperature T2, elemental iodine is added, the reaction vessel is sealed, and the reaction is carried out under stirring and heat preservation conditions; Post-processing: The reaction product is cooled and pulverized to obtain the antibacterial composition.

7. The method for preparing an antibacterial composition according to claim 6, characterized in that, The temperature T1 is 170-260℃, the vacuum condition is -0.06MPa to -0.09MPa, and the reaction time is 40-90 minutes.

8. The method for preparing an antibacterial composition according to claim 7, characterized in that, The temperature T2 is 80-110℃, and the heat preservation reaction time is 1.0-3.0 hours.

9. The method for preparing an antibacterial composition according to claim 7, characterized in that, Prior to the deep filling, the method also includes the step of preparing a porous inorganic support with hydrophobic interface modification. (1) The porous inorganic carrier is subjected to heating and degassing treatment; (2) Mix the treated carrier with the interface modifier; (3) The mixture is heated to temperature T0 and stirred under negative pressure. After cooling, the hydrophobic modified porous inorganic carrier is obtained.

10. A method for preparing an antibacterial composition according to claim 9, characterized in that, The temperature T0 is 130-160℃, and the negative pressure condition is a pressure of -0.01MPa to -0.05MPa.

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