Broad-spectrum efficient antibacterial polymer composite material as well as preparation method and application thereof

Abstract

The invention discloses a broad-spectrum efficient antibacterial polymer composite material as well as a preparation method and application thereof, and particularly relates to the technical field of production of polymer composite materials. According to the broad-spectrum efficient antibacterial polymer composite material, PA6 is used as a main body, an organic antibacterial pyridine ring and an inorganic antibacterial material metal silver are synthesized into an antibacterial agent, then long-chain quaternary ammonium salt is grafted, N-butylbenzenesulfonamide, thymol and the like are further compounded to serve as the antibacterial agent, and the broad-spectrum property and the high efficiency of the antibacterial property of the material are remarkably improved. The defects that a traditional antibacterial material is few in antibacterial variety, slow in effect taking time and short in acting time are effectively overcome; the antibacterial rate of gram-positive bacteria in 24 hours is larger than or equal to 99%, the virus titer of the film is reduced by 4.2 log10, the antibacterial rate in 1 hour reaches 92.1%, the dynamic friction coefficient is 0.2-0.4, the tensile strength is larger than or equal to 35 MPa, the hand feeling is not lost while the tensile strength and the antibacterial property are guaranteed, and the film is suitable for the fields of medical dressings, artificial joints, environment, industry and the like.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of polymer composite material preparation, and particularly relates to a broad-spectrum high-efficiency antibacterial polymer composite material and a production method thereof. BACKGROUND

[0002] In recent years, infectious diseases caused by pathogenic microorganisms such as bacteria and viruses have occurred frequently, not only directly threatening individual health, but also having a profound impact on community public health, the medical system and economic stability. The problems of cross-infection in hospital environment, microbial contamination in food packaging, and pathogen transmission on contact surfaces in public space make materials with long-acting antibacterial function a key link to protect public health safety. Traditional antibacterial materials, such as single antibiotics and small molecule bactericides, have been difficult to meet the broad-spectrum protection needs in complex scenarios due to their limited antibacterial range and the problem of easily causing microbial drug resistance, and it is urgent to develop broad-spectrum high-efficiency materials that can simultaneously inhibit gram-positive bacteria, gram-negative bacteria and some viruses.

[0003] Current antibacterial polymer materials are mainly based on two mainstream technical routes of chemistry and physics: the advantage of the chemical route is that such materials load biocides such as silver ions, zinc ions and small molecule organic bactericides in polymer matrices such as polyethylene, polylactic acid and nylon, and achieve antibacterial effect by slow leaching of biocides. For example, nanosilver particles are dispersed in polyvinyl alcohol (PVA) film to inhibit microbial growth by silver ion release; or adding thymol and other natural antibacterial agents in polylactic acid (PLA) fibers to achieve short-term antibacterial effect by small molecule migration. Its advantages are fast antibacterial effect and high initial antibacterial efficiency, and it is widely used in disposable medical products (such as masks, protective clothing), short-term food packaging and other scenarios.

[0004] The antibacterial performance of the polymer composite material prepared by the prior art is limited: it is difficult to balance broad-spectrum and long-acting: most single antibacterial materials are only effective against specific types of microorganisms, for example, silver-based antibacterial agents have significant inhibitory effect on bacteria, but have weak effect on envelope viruses and fungi such as Candida albicans, and need high concentration to act on gram-negative bacteria, and the response speed is slow and the cost is high. SUMMARY

[0005] In order to solve the problems of insufficient broad-spectrum performance, slow bacterial response, insufficient heat resistance and high cost of the broad-spectrum high-efficiency antibacterial polymer composite material in the prior art, the present application proposes a broad-spectrum high-efficiency antibacterial polymer composite material and its production method and application. In order to achieve the purpose of the present application, the following technical solutions are adopted:

[0006] The present application proposes a preparation method of a broad-spectrum high-efficiency antibacterial polymer composite material, which comprises the following components:

[0007] Carrier resin: polypropylene 40-50 parts;

[0008] Antibacterial agent: modified PA6 30-40 parts; thymol 5-8 parts; nano zinc powder 5-8 parts; N-butyl benzene sulfonamide 6-7 parts;

[0009] Dispersant: ethylene bis-stearamide and polyethylene wax 1:1 compound 3-5 parts;

[0010] Reinforcing agent: ternary ethylene propylene rubber 10-20 parts;

[0011] Lubricant: calcium stearate 1-2 parts;

[0012] The preparation method of the modified PA6 comprises the following steps:

[0013] S1. Preparation of antibacterial agent

[0014] S101. Generation of amide bond: dissolve 3-aminopyridine and triethylamine in acetonitrile solution, place in a round-bottom flask, slowly drop 30 mL of 1,3,5-benzene tricarbonyl chloride in dichloromethane solution under ice water bath with constant pressure funnel, stir for 2 h, remove the ice water bath, stir at room temperature for 48 h, collect the solid by filtration, wash with saturated NaHCO3, water, ethyl acetate, and vacuum dry to obtain yellow powder product, i.e. N1-phenyl-N3,N5-di(pyridin-3-yl)benzene-1,3,5-tricarbonyl amide; under the condition of ice water bath at 0-5℃, the amino nitrogen atom (containing lone pair of electrons) of 3-aminopyridine acts as a nucleophile to attack the carbonyl carbon (δ+) of the acyl chloride group in the 1,3,5-benzene tricarbonyl chloride molecule, forming a new C-N bond, while the carbonyl oxygen atom changes from double bond to single bond, accepting a lone pair of electrons to form an oxygen anion, generating unstable tetrahedral intermediate [C6H3(COCl)2(CO-NH-C5H4N)]. The function of the ice water bath is to reduce the reaction rate, avoid the side reactions such as hydrolysis of acyl chloride due to excessive heat release of the reaction, and reduce the disordered generation of polysubstituted products, thereby improving the selectivity of the target product; the tetrahedral intermediate is unstable, and the oxygen anion re-forms a carbonyl double bond (C=O) through electron transfer, while the chlorine atom connected to the carbonyl carbon leaves with a pair of electrons to form chloride ion (Cl-), and finally forms a stable amide bond (-CO-NH-). At this time, one acyl chloride group in the 1,3,5-benzene tricarbonyl chloride molecule is converted into an amide group, generating a monosubstituted intermediate [C6H3(COCl)2(CO-NH-C5H4N)]. Wash with saturated NaHCO3 to remove residual triethylamine hydrochloride [(C2H5)3NHCl]. - - - + - ​​​​] and unreacted 1,3,5-benzene tricarboxylic acid chloride hydrolysis product carboxylic acid; water washing is to further remove residual inorganic salts such as NaCl, triethylamine salt and water-soluble impurities such as excess 3-aminopyridine, under low-temperature ice bath conditions, the target product (yellow powder) has low solubility in ethyl acetate, while unreacted small amount of 1,3,5-benzene tricarboxylic acid chloride, mono / substituted intermediates and other organic impurities have high solubility in ethyl acetate, which can be removed by washing to improve the purity of the product.

[0015]

[0016] S102. Silver ion impregnation: N1-phenyl-N3,N5-di(pyridin-3-yl)benzene-1,3,5- triformamide obtained in S101 is added to anhydrous ethanol, heated to 77°C, and after complete dissolution, silver trifluoroacetate is added to the solution, heated and condensed under reflux at 60°C, and reacted for 24 h; after the solution is completely cooled, centrifugal filtration is performed, washed with ultrapure water three times, and vacuum dried; N1-phenyl-N3,N5-di(pyridin-3-yl)benzene-1,3,5-triformamide silver is obtained in the form of a brown powder; when the triformamide ligand is dissolved in anhydrous ethanol by heating to 77°C, multiple nitrogen-containing sites in the molecular structure of the triformamide ligand, such as the nitrogen atoms on the pyridine ring and the nitrogen atoms in the amide bond, become potential coordination active centers due to the presence of lone pair electrons; the electronegativity of the nitrogen atom on the pyridine ring is 3.04, and its lone pair electron does not participate in the conjugate system; although the electron cloud density of the nitrogen atom in the amide bond is slightly lower due to the electron-withdrawing effect of the carbonyl group, it can still provide a lone pair electron to lay the foundation for combination with silver ions. The role of anhydrous ethanol is to weaken the intermolecular forces of the ligand through a polar solvent environment (dielectric constant 24.5) to promote its dissolution and expose the coordination sites, avoid the interference of water with the combination of silver ions and the ligand, and prevent the hydrolysis of silver ions to generate silver hydroxide or silver oxide.

[0017] The subsequently added silver trifluoroacetate (AgTFA) dissociates in the ethanol solution to generate Ag + and CF3COO - —Ag + As a soft acid, it has strong affinity for soft base coordination atoms such as nitrogen, and will preferentially coordinate with the nitrogen atoms on the pyridine ring in the triformamide ligand: the empty orbital of Ag + accepts the lone pair electron of the nitrogen atom on the pyridine ring to form a coordination bond. Since three pyridine rings are symmetrically distributed in the triformamide ligand molecule, each ligand molecule can form a polydentate coordination structure with Ag + through multiple pyridine ring nitrogen atoms, which can significantly improve the stability of the complex and avoid easy dissociation of Ag + in the subsequent process. At the same time, the nitrogen atom in the amide bond may assist in stabilizing Ag +This further enhances the compactness of the complex structure. The reaction system was refluxed at 60°C for 24 hours, which, on the one hand, promoted the Ag... + The collision frequency with ligand molecules accelerates the complete coordination reaction, ensuring that each Ag... + Both can form stable complexes with ligands; on the other hand, the reflux device can prevent the evaporation of ethanol solvent from causing abnormal concentrations and avoid local Ag... + When the concentration is too high, the silver particles agglomerate and form amorphous particles.

[0018] During the reaction, trifluoroacetate (CF3COO) - As an anion after dissociation, Ag mainly plays a role in balancing the charge—when Ag + When CF3COO forms a coordination complex with a neutrally charged triformamide ligand, - The silver-trimethylamide complex adsorbs onto the surface of the complex via electrostatic attraction, maintaining the electroneutrality of the system. However, due to its weak binding force with the complex, it can be removed by washing. Upon cooling of the solution after the reaction, the silver-trimethylamide coordination complex precipitates as its solubility decreases, and the ethanol solvent's ability to dissolve the polar complex diminishes at low temperatures, forming solid particles. Centrifugal filtration separates the solid complex from the solution using centrifugal force. Three washes with ultrapure water utilize the polarity of water to remove the CF3COO adsorbed on the complex surface. - Unreacted AgTFA and a small amount of free ligands were dissolved and removed—CF3COO - Easily soluble in water, unreacted Ag + A small amount of Ag can be formed in water. + Hydrated ions are washed away, and although the free ligands have low solubility in water, repeated washing can significantly reduce their residue. The final vacuum drying step is carried out at a low temperature, which removes the water adsorbed on the surface of the complex while avoiding the decomposition of the complex due to the destruction of the Ag-N coordination bond by high temperature. The final product is a brown powdery antibacterial agent—the brown color originates from the characteristic absorption of the silver-ligand complex, while the antibacterial activity comes from the complexed Ag. + Its slow-release ability allows it to exert antibacterial effects by interacting with bacteria.

[0019] R1 is a pyridinyl group.

[0020] S2. Grafting of long-chain quaternary ammonium salts

[0021] The PA6 / PVA high polymer composite is treated by padding with a completely soluble methacryloyloxyethyl trimethyl ammonium chloride padding liquid at room temperature; then it is taken out of the padding bath, squeezed to 80% belt liquid rate using a laboratory padder, and then dried in an oven at 80°C for 30 min, and finally cured at 120°C for 50 min; after the reaction is completed, the product is cooled to room temperature in a desiccator until a constant weight is reached; the dried sample is washed with hot water five times to remove the polymethacryloyloxyethyl trimethyl ammonium chloride homopolymer; and then it is placed in a 10% sodium nitrate solution, passed through a resin column at a flow rate of 1-2 BV / h until the effluent has no silver nitrate precipitate, concentrated under reduced pressure at a temperature of 50-55°C, cooled and crystallized, and dried in an oven at 30°C for 24 h to obtain the quaternary ammonium salt grafted PA6; during the room temperature padding stage, the structure of the PA6 / PVA high polymer composite provides multiple adsorption sites for the methacryloyloxyethyl trimethyl ammonium chloride (DMC) molecules; during the 80°C drying process, as the water evaporates, the DMC monomers gradually accumulate inside and on the surface of the fibers, and the intermolecular distance shortens, but the carbon-carbon double bonds (C=C) in the DMC molecules remain chemically active and do not undergo polymerization—low-temperature drying can avoid premature polymerization of the monomers to form homopolymers, ensuring that they are uniformly distributed in the fiber matrix in a free state; during the 120°C curing stage, ammonium persulfate attacks the hydrogen on the nitrogen atom of PA6 to form N· free radicals, and then the carbon-carbon double bonds (C=C) undergo radical polymerization at this temperature, anchoring the quaternary ammonium salt long chain to the PA6 molecular chain by chemical bonds to achieve graft copolymerization. This covalent bonding is different from simple physical adsorption and can significantly improve the binding strength of the quaternary ammonium salt to the fiber, laying the foundation for subsequent wash resistance.

[0022] The purpose of the hot water washing step is to remove PDMC homopolymers that do not participate in grafting: the homopolymers are combined with the fibers only by physical entanglement or weak interaction, and their solubility increases in hot water (temperature higher than the glass transition temperature of the homopolymer), so they can be effectively removed after five washes; while the covalently grafted PDMC segments remain stably attached to the PA6 molecular chain due to chemical bonds, and the chloride ions are replaced by nitrate ions through anion exchange resin; finally, the residual water is removed by low-temperature drying to obtain the quaternary ammonium salt grafted PA6 molecular chain.

[0023]

[0024] S3. Modification of PA6

[0025] The grafting quaternary ammonium salt island fiber obtained in S2 is weighed and added into the trifluoroethanol solution, and the reaction vessel is placed in a parallel synthesizer and heated and stirred at 60°C for 2h. After the reaction is completely dissolved, the obtained antibacterial agent N1-phenyl-N3, N5-di(pyridin-3-yl)benzene-1, 3, 5-triformamide silver in S1 is added and stirred at 60°C for 1h. The nano-silver is weighed and added into the reaction system, and continues to be stirred at 60°C for 1h. After the stirring is completed, ultrasonic treatment is performed for 0.5h to obtain the modified PA6, and further processing is performed to obtain a broad-spectrum and high-efficiency antibacterial polymer composite material. As a strong polar fluorine-containing solvent, the hydroxyl (-OH) and fluorine atom (-F) in the molecule of trifluoroethanol can destroy the intermolecular force of the PA6 / PVA polymer composite material of the grafting quaternary ammonium salt through hydrogen bonding and dipole interaction. For the PVA marine phase, the hydroxyl of trifluoroethanol and the hydroxyl of PVA form competitive hydrogen bonds, weakening the entanglement between PVA molecular chains. For the PA6 island phase, the strong polarity of trifluoroethanol can penetrate between the amide bonds of PA6, reducing the regularity of the crystalline region. At the same time, the quaternary ammonium salt group (-N + (CH3)3) and the fluorine atom of trifluoroethanol form electrostatic attraction, further promoting the gradual dissolution of the fiber under heating and stirring at 60°C to form a uniform polymer solution, creating conditions for the subsequent molecular dispersion of the components.

[0026] After adding the antibacterial agent obtained in S1, the nitrogen atom of the pyridine ring and the oxygen atom of the amide bond in the molecular structure can form hydrogen bonds with the polar groups of PA6 / PVA in the solution, and at the same time, the cationic group of the quaternary ammonium salt produces electrostatic interaction. The silver ion in the antibacterial agent forms a charge balance with the cation of the quaternary ammonium salt, so that the antibacterial agent is uniformly dispersed and anchored on the polymer chain through multiple secondary bonds, avoiding agglomeration. After the addition of nano-silver, the silver atoms on the surface can form coordinate bonds (Ag-N bonds) with the nitrogen atoms of the pyridine ring in the antibacterial agent, and at the same time, electrostatic adsorption with the chloride ions or other anions of the quaternary ammonium salt, forming an antibacterial agent-nano-silver composite unit; the composite unit is stably combined in the PA6 / PVA matrix through the hydrogen bonding between the antibacterial agent and the polymer chain. Stirring at 60°C promotes the uniform distribution of nano-silver in the solution, and the subsequent ultrasonic treatment for 0.5h further breaks down the possible nano-silver agglomerates through high-frequency mechanical vibration, refines the particle size and uniformly embeds the nano-silver in the polymer network, ensuring the dispersibility of the antibacterial component.

[0027]

[0028]

[0029] Preferably, the molar ratio of the raw materials used in S101 is: 3-amino pyridine: 1, 3, 5-benzene tricarboxylic acid chloride = 3.0-3.1:1; the addition amount of triethylamine is 10% of the total amount of the system.

[0030] Preferably, the mass fraction of the solute of the 1,3,5-benzene tricarbonyl chloride dichloromethane solution used in S101 is 70%; the yield of the reaction is about 40-50%.

[0031] Preferably, the molar ratio of the raw materials used in S102 is: N1-phenyl-N3, N5-di(pyridine-3-yl) benzene-1,3,5-tricarboxamide obtained from S101: silver trifluoroacetate = 1:3.0-3.1.

[0032] Preferably, the methyl acryloyloxyethyl trimethyl ammonium chloride padding solution used in S2 is a 10% solution by mass fraction, and contains 2.0 g / L of potassium persulfate.

[0033] Preferably, the mass fraction of the raw materials used in S2 is: PA6 / PVA high molecular composite 60-70 parts, methyl acryloyloxyethyl trimethyl ammonium chloride padding solution 50-60 parts.

[0034] Preferably, the mass fraction of the raw materials used in S2 is: PA6 / PVA high molecular composite 60-70 parts, methyl acryloyloxyethyl trimethyl ammonium chloride padding solution 50-60 parts.

[0035] Preferably, the further processing in S3 includes the following steps:

[0036] 1) Pretreatment: dry the modified PA6 obtained from S3 in an oven at 80-100°C for 4-6h, control the water content to ≤0.1%, prevent bubbles during extrusion; first add the dried modified PA6, dispersant, antioxidant in a high-speed mixer, mix at low speed for 2min; then add the premixed thymol, nano zinc powder, N-butyl benzene sulfonamide, calcium stearate, mix at high speed for 5-8min, until the material is uniform and no obvious particles;

[0037] 2) Initial plasticization: set the initial feeding speed to 30-50rpm, match the screw speed, ensure continuous feeding of the material; check the gap between the cutter blades to be 0.1-0.2mm, run for 30 seconds under no load, ensure smooth rotation of the blades without abnormal noise; add water to the cooling water tank to a depth of 15-20cm, start the temperature controller to adjust the water temperature to 20-30°C; start the twin-screw extruder, start the screw at 100rpm, gradually increase to 300-400rpm, avoid instantaneous overload, after the screw runs smoothly, start the feeder, send the pre-mixed material modified PA6+antibacterial agent+additives into the hopper at a uniform speed;

[0038] 3) melt molding: after the melt is extruded from the die, immediately use a traction roller, the speed is 5%-10% faster than the extrusion speed, the strip material is pulled to the cooling water tank, to ensure that the strip material is straight without bending; the cutter rotation speed is 500-800 rpm, matched with the traction speed, to ensure that the particle length is 3-5 mm; immediately use a vibrating screen after cutting, the screen mesh aperture is 2-6 mm, the qualified particles are sent into a hot air circulating oven, dried at 80-90 DEG C for 2-3h, turn over every 1h to ensure uniform drying, the final moisture content is controlled to be ≤0.05%, the dried master batch is hot filled into an aluminum foil bag, sealed after vacuumizing, and the bag is marked with batch, type of antibacterial agent and addition amount.

[0039] Further, the prepared broad-spectrum high-efficiency antibacterial high polymer composite material can be applied to medical dressings, artificial joints, home, personal care, biological environment and the like.

[0040] 1) medical dressing: the product needs to be sterilized by 121 DEG C high-pressure steam for 30 min to remove microbial contamination, and at the same time, γ-ray irradiation is used, the dose is 25-30 kGy, combined with other medicaments, and applied to the wound surface of the patient;

[0041] 2) artificial joint: the product needs to be polished to make the roughness Ra≤0.2 μm, to reduce the bacterial adhesion site, and at the same time, the antibiotic release rate is verified by in-vitro simulation of body fluid immersion under the condition of 37 DEG C, to ensure that the effective antibacterial concentration is maintained for 6-8 weeks;

[0042] 3) household and commodity field: after the antibacterial plastic is formed, nano-SiO2 coating treatment is needed to improve the oil stain resistance;

[0043] 4) personal care products: the antibacterial fiber fabric needs to add 0.5%-1% silicon oil to improve the use comfort and avoid skin irritation caused by the antibacterial agent;

[0044] 5) water treatment filter material: the antibacterial film needs to be adjusted to have a pore size of 0.1-1 μm, and the water flux is ≥100 L / (m 2 ·h), and at the same time, the acid and alkali resistance test of pH 3-11 is carried out to adapt to complex water quality;

[0045] 6) air purification filter screen: the antibacterial non-woven fabric needs to be treated by static electrification with a voltage of 5-10 kV to improve the dust capture capacity and retain the antibacterial performance.

[0046] The beneficial effects of the application are:

[0047] (1) The present application effectively solves the problems of long-acting but slow response of organic antibacterial agents and fast response but short life of inorganic antibacterial agents by chemically bonding organic pyridine ring and inorganic silver ions, and the synthesized antibacterial agent combines the advantages of both to achieve full coverage and efficient killing of different types of microorganisms. In the antibacterial agent prepared by S1, the nitrogen atom of the pyridine ring can form a stable complex with silver ions, and the silver ions combine with active groups such as sulfhydryl and amino groups of microorganisms by slow release, inhibit enzyme activity and DNA replication, and the rigid aromatic structure of benzene triformamide can enhance the penetration ability of the cell wall of microorganisms; nano-silver releases more silver ions and produces active oxygen by virtue of high specific surface area, further strengthening the inactivation effect on enveloped viruses and non-enveloped viruses, and under the synergistic action, the antibacterial rate of the composite material to gram-positive bacteria, gram-negative bacteria, fungi and viruses can reach more than 99%, and the antibacterial response speed is fast, which can significantly inhibit the activity of microorganisms within 30 minutes after contact, solving the limitation of single antibacterial component that the effect on specific microorganisms is not good.

[0048] (2) The present application further improves the positive charge of quaternary ammonium salt group by relying on covalent grafting of long-chain quaternary ammonium salt, which can adsorb negatively charged bacteria such as Escherichia coli and Staphylococcus aureus and the cell membrane of fungi such as Candida albicans by electrostatic action, destroy the membrane structure integrity, cause cell content leakage, and realize contact death; when the addition amount of quaternary ammonium salt is 9%, the antibacterial rate of the composite fiber to Escherichia coli is increased to 99.99%, and to Staphylococcus aureus is 99.81%. Compared with surface grafting, the density of antibacterial groups is higher, and can continuously contact with microorganisms, avoiding the antibacterial blind area.

[0049] (3) The present application realizes long-acting antibacterial through the dual mechanism of chemical bonding + slow release regulation. In S2 step, quaternary ammonium salt is covalently bonded with PA6 by in-situ grafting and is not easy to fall off during water washing; the antibacterial agent prepared by S1 can be firmly anchored inside the fiber due to the hydrogen bonding and coordination action with PA6 molecular chain, avoiding the migration and loss of traditional physical mixed antibacterial agent; nano-silver forms a slow-release library by the coating of antibacterial agent and the adsorption of fiber matrix, continuously releases low-concentration silver ions in long-term use, and maintains the antibacterial activity. After 50 times of water washing test, the antibacterial rate of the composite material to Escherichia coli and Staphylococcus aureus still remains more than 96%, far exceeding the washing resistance standard of conventional antibacterial fabrics, and can meet the long-term use requirements of medical, underwear, home textile and other high-frequency washing scenes.

[0050] (4) The application selects water-soluble marine island fibers of marine facies, improves the environmental protection of the material, and balances the antibacterial function and use comfort. The superfine fibers formed after the dissolution of the marine facies can improve the moisture absorption performance of the fibers through the hydroxyl structure of PVA; the mild padding-curing process in the S2 step avoids the damage to the fiber structure caused by high temperature and high pressure, and the 80% liquid retention rate and low-temperature drying parameters can reduce fiber shrinkage and stiffening; in the S3 step, trifluoroethanol as an environmentally friendly solvent can quickly dissolve the fibers and the antibacterial components, and the subsequent removal of the homopolymer by hot water washing avoids skin irritation caused by residual chemical reagents; at the same time, the particle sizes of the nano-silver and the antibacterial agent are controlled at the nanometer level, and they are uniformly dispersed in the fibers, so that the fabric does not have a rough grainy feeling, keeps a soft touch and good air permeability, and has no foreign body sensation when it is close to the skin, meeting the skin-friendly requirements of close-fitting fabrics such as underwear and baby clothes.

[0051] (5) The application strengthens the structural stability of the PA6 / PVA high polymer composite material through multiple interface effects. On the one hand, in the S2 step, the methacryloyloxyethyl trimethyl ammonium chloride (DMC) is grafted to the PA6 molecular chain by in-situ copolymerization, the quaternary ammonium salt group of DMC can form strong electrostatic interaction and hydrogen bond with the terminal amino group and the terminal carboxyl group of PA6, and the vinyl double bond of DMC can add to the macromolecular free radical of PA6 to form a grafted copolymer connected by covalent bond, which effectively reduces the slippage between the molecular chains of the fibers and improves the tensile resistance of the fibers; on the other hand, in the S3 step, trifluoroethanol as a good solvent can promote the uniform dispersion of the grafted quaternary ammonium salt island fibers, the antibacterial agent and nano-silver prepared in S1, the amide bond and pyridine ring in the antibacterial agent molecule can form intermolecular hydrogen bond with the amide group of PA6, and nano-silver is embedded into the gap inside the fiber through physical filling effect, further enhancing the structural density of the fiber, avoiding the problem of mechanical property decline caused by antibacterial component agglomeration in traditional antibacterial modification, so that the finally prepared composite material applied in various fields still maintains excellent tensile strength and elongation at break, meeting the wear resistance and tear resistance requirements in actual use. BRIEF DESCRIPTION OF DRAWINGS

[0052] Figure 1 NMR spectrum of N1-phenyl-N3,N5-di(pyridin-3-yl)benzene-1,3,5-tricarboxamide prepared in Example 2;

[0053] Figure 2 NMR spectrum of quaternary ammonium salt grafted PA6 / PVA high polymer composite material prepared in Example 2. DETAILED DESCRIPTION

[0054] The technical solutions of the present application and their effects will be further described below with reference to the drawings in the embodiments of the present application. The following embodiments are only used to illustrate the content of the present application and are not used to limit the protection scope of the present application. Simple changes made by applying the concept of the present application to the present application are within the scope of the present application.

[0055] The sources of the materials in the following examples and comparative examples are as follows:

[0056] PA6 / PVA high molecular composite material: Guangzhou Huhuan Chemical Auxiliary Co., Ltd.;

[0057] 3-aminopyridine: Shanghai Aladdin Science and Technology Co., Ltd.;

[0058] Triethylamine: Shanghai Aladdin Science and Technology Co., Ltd.;

[0059] 1,3,5-benzene tricarboxylic acid chloride-containing dichloromethane solution: Guangzhou Huhuan Chemical Auxiliary Co., Ltd.;

[0060] Silver trifluoroacetate: Guangzhou Huhuan Chemical Auxiliary Co., Ltd.;

[0061] Methacryloyloxyethyl trimethyl ammonium chloride padding liquor

[0062] N-butyl benzene sulfonamide: Guangzhou Anjiang Chemical Reagent Co., Ltd.;

[0063] Anhydrous methanol: Shanghai Aladdin Science and Technology Co., Ltd.;

[0064] Acetonitrile: Shanghai Aladdin Science and Technology Co., Ltd.;

[0065] Ethyl acetate: Shanghai Aladdin Science and Technology Co., Ltd.;

[0066] Silver trifluoroacetate: Shanghai Maikelin Biological Technology Co., Ltd.;

[0067] Trifluoroethanol: Shanghai Maikelin Biological Technology Co., Ltd.;

[0068] Deionized water: self-made.

[0069] Examples 1-3 and comparative examples 1-8 all use the synthesis method of the broad-spectrum and high-efficiency antibacterial high molecular composite material in the present application.

[0070] Example 1: Preparation of S1.N1-phenyl-N3,N5-di(pyridin-3-yl)benzene-1,3,5-tricarboxamide silver

[0071] S101. Amide bond formation: 28.5 g of 3-aminopyridine, 5.85 g of triethylamine were dissolved in acetonitrile solution, placed in a round-bottom flask, and 30 mL of 1,3,5-benzene tricarbonyl chloride in dichloromethane solution was slowly dropped into the flask through a constant pressure funnel under ice water bath, stirred for 2 h, then the ice water bath was removed, and stirred at room temperature for 48 h. The solid was collected by filtration, washed with saturated NaHCO3, water, and ethyl acetate, and dried in vacuum to obtain the product, N1-phenyl-N3,N5-di(pyridin-3-yl)benzene-1,3,5-tricarboxamide, in the form of yellow powder;

[0072] S102. Silver ion impregnation: 40 g of N1-phenyl-N3,N5-di(pyridin-3-yl)benzene-1,3,5-tricarboxamide obtained in S101 was added to anhydrous ethanol, heated to 77°C, and after complete dissolution, 65 g of silver trifluoroacetate was added to the solution, and heated and condensed under reflux at 60°C for 24 h. After the solution was completely cooled, it was centrifuged and filtered, washed with ultrapure water three times, and dried in vacuum to obtain the antibacterial agent in the form of brown powder;

[0073] S2. Grafting of long-chain quaternary ammonium salt

[0074] 60 g of PA6 / PVA high molecular composite material was padded with 80 mL of completely soluble methacryloyloxyethyl trimethyl ammonium chloride padding solution at room temperature; then it was taken out of the padding bath, squeezed to 80% belt liquid rate using a laboratory padder, and then dried in an oven at 80°C for 30 min, and finally cured at 120°C for 50 min. After the reaction was completed, the product was cooled to room temperature in a desiccator until a constant weight was reached. The dried sample was washed with hot water five times to remove polymethacryloyloxyethyl trimethyl ammonium chloride homopolymer; then it was placed in a 10% sodium nitrate solution, passed through a resin column at a flow rate of 1-2 BV / h until there was no precipitation of silver nitrate in the effluent, concentrated under reduced pressure at a temperature of 50-55°C, and cooled to crystallize, and then dried in an oven at 30°C for 24 h to obtain the quaternary ammonium salt grafted PA6;

[0075] S3. Modification of PA6

[0076] 50 mL of trifluoroethanol was measured in a container, and 65 g of the island fiber of the grafted quaternary ammonium salt obtained in S2 was added to the trifluoroethanol solution. The reaction vessel was placed in a parallel synthesizer and heated and stirred at 60°C for 2 h. After the reactants were completely dissolved, 85 g of the antibacterial agent obtained in S1 was added, and stirred at 60°C for 1 h. Nano-silver was added to the reaction system, and stirring was continued at 60°C for 1 h. After stirring was completed, ultrasonic treatment was performed for 0.5 h to obtain the modified PA6. Further treatment was performed to obtain a broad-spectrum high-efficiency antibacterial high molecular composite material. The further treatment process includes (the same as other examples and comparative examples):

[0077] 1) Pretreatment: The modified PA6 obtained in S3 and polypropylene were dried in an oven at 80-100°C for 4-6h, and the water content was controlled at ≤0.1% to prevent bubbles during extrusion; in a high-speed mixer, the dried modified PA6, dispersant, and antioxidant were first added, and mixed at low speed for 2min; then the premixed thymol, nano-zinc powder, N-butyl benzene sulfonamide, and calcium stearate were added, and mixed at high speed for 5-8min until the material was uniform and no obvious particles were present;

[0078] 2) Initial plasticization: the initial feeding speed was set to 30-50rpm to match the screw speed, and ensure continuous feeding of the material; the gap between the pelletizer blades was checked to be 0.1-0.2mm, and the idle running was tested for 30 seconds to ensure smooth rotation of the blades without abnormal noise; the cooling water tank was filled with water to a depth of 15-20cm, and the water temperature was adjusted to 20-30°C using a temperature controller; the twin-screw extruder was started, and the screw speed was gradually increased from 100rpm to 300-400rpm to avoid instantaneous overload; after the screw ran smoothly, the feeder was turned on, and the pre-mixed material modified PA6+antibacterial agent+additives was fed into the hopper at a uniform speed;

[0079] 3) Melt forming: after the melt was extruded from the die, it was immediately pulled by a traction roller at a speed 5%-10% faster than the extrusion speed to stretch the strip to the cooling water tank to ensure that the strip was straight without bending; the cutter speed was 500-800rpm to match the traction speed, and ensure that the particle length was 3-5mm; after cutting, the qualified particles were immediately sent to a hot air circulating oven through a vibrating screen with a mesh size of 2-6mm, and dried at 80-90°C for 2-3h, with the material being turned over every 1h to ensure uniform drying, and the final water content was controlled at ≤0.05%; the dried masterbatch was immediately packed in an aluminum foil bag, vacuum sealed, and labeled with the batch number, type of antibacterial agent, and addition amount on the outside of the bag.

[0080] Example 2: Preparation of S1.N1-phenyl-N3,N5-di(pyridin-3-yl)benzene-1,3,5-tricarboxamide silver

[0081] S101. Formation of amide bond: 28.5g of 3-aminopyridine and 6.25g of triethylamine were dissolved in an acetonitrile solution, and placed in a round-bottom flask. A 35mL solution of 1,3,5-benzene tricarboxylic acid chloride in dichloromethane was slowly added dropwise through a constant pressure funnel under an ice water bath, and stirred for 2h. After removing the ice water bath, it was stirred at room temperature for 48h. The solid was collected by filtration, washed with saturated NaHCO3, water, and ethyl acetate, and dried under vacuum to obtain a yellow powder product, which was N1-phenyl-N3,N5-di(pyridin-3-yl)benzene-1,3,5-tricarboxamide; Figure 1The characteristic peaks of aromatic hydrogen appearing at 7-9.5 ppm prove the existence of phenyl and pyridine ring structure in the molecule; the characteristic peaks of amido hydrogen appearing at 5-8 ppm prove the formation of amido bond (-CO-NH-);

[0082] S102. Silver ion impregnation: 52 g of N1-phenyl-N3,N5-di(pyridine-3-yl)benzene-1,3,5-triformamide obtained in S101 was added to anhydrous ethanol, heated to 77°C, and after complete dissolution, 55 g of silver trifluoroacetate was added to the solution, and heated and condensed under reflux at 60°C for 24 h; after the solution was completely cooled, it was centrifuged and filtered, washed with ultrapure water three times, and dried in vacuum. An antibacterial agent in the form of a brown powder was obtained;

[0083] S2. Grafting of long-chain quaternary ammonium salt

[0084] 65 g of PA6 / PVA high molecular composite material was padded with 70 mL of completely soluble methacryloyloxyethyl trimethyl ammonium chloride padding solution at room temperature; then it was taken out of the padding bath, squeezed to 80% wet pick-up using a laboratory mangle, and then dried in an oven at 80°C for 30 min, and finally cured at 120°C for 50 min; after the reaction was completed, the product was cooled to room temperature in a desiccator until a constant weight was reached; the dried sample was washed with hot water five times to remove polymethacryloyloxyethyl trimethyl ammonium chloride homopolymer; then it was placed in a 10% sodium nitrate solution, passed through a resin column at a flow rate of 1-2 BV / h until the effluent was free of silver nitrate precipitate, concentrated under reduced pressure at a temperature of 50-55°C, cooled and crystallized, and dried in an oven at 30°C for 24 h to obtain quaternary ammonium salt grafted PA6;

[0085] S3. Modification of PA6

[0086] 50 mL of trifluoroethanol was measured into a container, and 70 g of island-in-sea fiber grafted with quaternary ammonium salt obtained in S2 was added to the trifluoroethanol solution, and the reaction vessel was placed in a parallel synthesizer and heated and stirred at 60°C for 2 h; after the reactants were completely dissolved, 80 g of antibacterial agent obtained in S1 was added, and stirred at 60°C for 1 h; then 10 g of nano-silver was added to the reaction system, and stirring was continued at 60°C for 1 h; after stirring was completed, ultrasonic treatment was performed for 0.5 h to obtain modified PA6, and further processing was performed to obtain a broad-spectrum high-efficiency antibacterial high molecular composite material.

[0087] Example 3: Preparation of S1. N1-phenyl-N3,N5-di(pyridine-3-yl)benzene-1,3,5-triformamide silver

[0088] S101. Amide bond formation: 28.5 g of 3-aminopyridine, 6.85 g of triethylamine were dissolved in acetonitrile solution, placed in a round-bottom flask, and 40 mL of 1,3,5-benzotri carbonyl chloride in dichloromethane solution was slowly dropped into the flask through a constant pressure funnel under ice water bath, stirred for 2 h, then the ice water bath was removed, and stirred at room temperature for 48 h. The solid was collected by filtration, washed with saturated NaHCO3, water, ethyl acetate, and dried in vacuum to obtain the product, N1-phenyl-N3,N5-di(pyridin-3-yl)benzene-1,3,5-tricarboxamide, in the form of yellow powder;

[0089] S102. Silver ion impregnation: 44 g of N1-phenyl-N3,N5-di(pyridin-3-yl)benzene-1,3,5-tricarboxamide obtained in S101 was added to anhydrous ethanol, heated to 77°C, and after complete dissolution, 45 g of silver trifluoroacetate was added to the solution, and heated and condensed under reflux at 60°C for 24 h. After the solution was completely cooled, it was centrifuged and filtered, washed with ultrapure water three times, and dried in vacuum to obtain the antibacterial agent in the form of brown powder;

[0090] S2. Grafting of long-chain quaternary ammonium salt

[0091] 70 g of PA6 / PVA high molecular composite material was padded with 60 mL of completely soluble methacryloyloxyethyl trimethyl ammonium chloride padding solution at room temperature; then it was taken out of the padding bath, squeezed to 80% belt liquid rate using a laboratory padder, and then dried in an oven at 80°C for 30 min, and finally cured at 120°C for 50 min. After the reaction was completed, the product was cooled to room temperature in a desiccator until a constant weight was reached. The dried sample was washed with hot water five times to remove polymethacryloyloxyethyl trimethyl ammonium chloride homopolymer; then it was placed in a 10% sodium nitrate solution, passed through a resin column at a flow rate of 1-2 BV / h until the effluent was free of silver nitrate precipitate, concentrated under reduced pressure at a temperature of 50-55°C, and cooled to crystallize. The product was dried in an oven at 30°C for 24 h to obtain quaternary ammonium salt grafted PA6;

[0092] S3. Modification of PA6

[0093] 50 mL of trifluoroethanol was measured in a container, and 75 g of island-in-sea fibers grafted with quaternary ammonium salt obtained in S2 was added to the trifluoroethanol solution. The reaction vessel was placed in a parallel synthesizer and heated and stirred at 60°C for 2 h. After the reactants were completely dissolved, 75 g of the antibacterial agent obtained in S1 was added, and stirred at 60°C for 1 h. Nano-silver was added to the reaction system, and stirring was continued at 60°C for 1 h. After stirring was completed, ultrasonic treatment was performed for 0.5 h to obtain modified PA6. Further treatment obtained a broad-spectrum high-efficiency antibacterial high molecular composite material.

[0094] Comparative Example 1

[0095] The same as example 2, except that 1,3,5 benzene tricarboxylic acid chloride is replaced by benzoyl chloride in step S1.

[0096] Comparative example 2

[0097] The same as example 2, except that anion impregnation is not used in step S102.

[0098] Comparative example 3

[0099] The same as example 2, except that the bacteriostatic agent prepared in step S1 is not added.

[0100] Comparative example 4

[0101] The same as example 2, except that the long chain quaternary ammonium salt is not added, i.e. step S2 is missing.

[0102] Comparative example 5

[0103] The same as example 2, except that the PA6 / PVA high molecular composite in step S2 is replaced by PA6 fiber.

[0104] Comparative example 6

[0105] The same as example 2, except that the nano silver is not added.

[0106] Comparative example 7

[0107] The same as example 2, except that N, butyl benzene sulfonamide is not added in the process strengthening step.

[0108] Comparative example 8

[0109] Broad-spectrum high-efficiency antibacterial high molecular composite material sold by Beijing Aisel Technology Co., Ltd.

[0110] The broad-spectrum and high-efficiency antibacterial high polymer composite material prepared in Examples 1-3 and Comparative Examples 1-8 was tested for its broad-spectrum, high efficiency, mechanical strength, and skin-friendliness in terms of antibacterial performance according to GB / T 20944.1-2007: "Evaluation of Antibacterial Performance Part 1: Agar Plate Diffusion Method", GB / T 20944.2-2007: "Evaluation of Antibacterial Performance Part 2: Absorption Method", GB / T 1040.1-2018: "Determination of Tensile Properties of Plastics Part 1: General Principles", GB / T 9341-2008: "Determination of Flexural Properties of Plastics", GB / T 3923.1-2013: "Textiles - Determination of Tensile Properties of Fabrics - Part 1: Determination of Breaking Force and Elongation at Break (Strip Method)", and GB 31701-2015: "Technical Specifications for Safety of Infant and Children's Textile Products". The corresponding results and data were summarized and plotted in Table 1-2:

[0111] Table 1: Broad-spectrum testing of the broad-spectrum and high-efficiency antibacterial high polymer composite material prepared in Examples 1-3 and Comparative Examples 1-8

[0112]

[0113] As shown in Table 1, in Examples 1-3, the performance of Example 2 was the best. From the microscopic mechanism, it is closely related to the molecular structure design and synergistic effect of the antibacterial agent. In the preparation of S1 stage, Example 2 uses 1,3,5-benzene tricarbonyl chloride as the cross-linking core, which reacts with 3-aminopyridine to form N1-phenyl-N3,N5-di(pyridin-3-yl)benzene-1,3,5-tricarbonyl amide with a symmetrical triamide structure. The nitrogen atom on the pyridine ring can form a stable complex system with silver ions from silver trifluoroacetate through coordination, and the three functional group structure of 1,3,5-benzene tricarbonyl chloride can construct more dense antibacterial active sites. Compared with the linear molecule formed by replacing benzoyl chloride with a single functional group in Comparative Example 1, the active sites are more uniform and have higher density, which can simultaneously interact with the cell membrane surface groups of different types of microorganisms. For bacteria such as Escherichia coli and Staphylococcus aureus, the cationic silver-amide complex can be attached to the negatively charged bacterial cell membrane through electrostatic attraction, destroy the membrane structure integrity, and cause intracellular material leakage. For fungi such as Candida albicans, the complex can also penetrate the chitin layer of the cell wall, inhibit intracellular enzyme activity and nucleic acid synthesis, and achieve antibacterial effect across different types of microorganisms.

[0114] Secondly, the in-situ co-grafted quaternary ammonium salt, methacryloyloxyethyl trimethyl ammonium chloride, further strengthens the micro foundation of broad-spectrum. The ratio of 65 g PA6 / PVA high polymer composite material to 70 mL quaternary ammonium salt padding liquid in Example 2 can form a moderate density of quaternary ammonium salt cation layer on the surface of the material. The long-chain alkyl of the quaternary ammonium salt can insert into the phospholipid bilayer of the microbial cell membrane, and form a synergistic destruction effect with the silver-amide complex. Silver ions mainly damage microbial DNA through oxidation, while quaternary ammonium salts focus on physically destroying the membrane structure. Both of them attack the microorganisms from different paths, avoiding the development of microbial resistance under a single antimicrobial mechanism, and covering the different structural weaknesses of Gram-negative bacteria such as E. coli, Gram-positive bacteria such as Staphylococcus aureus, and fungi such as Candida albicans, such as the outer membrane lipoprotein of Gram-negative bacteria, the thick peptidoglycan layer of Gram-positive bacteria, and the chitin cell wall of fungi, which can be effectively broken through by this synergistic system.

[0115] From the application level, after the PVA in the PA6 / PVA high polymer composite material of Example 2 is removed by marine dissolution, the porous structure formed by the PA6 island phase provides a good slow-release channel for the antimicrobial agents, silver-amide complex and quaternary ammonium salt. In the agar plate diffusion test, the active ingredients can slowly and continuously diffuse into the surrounding medium, forming a larger inhibition zone. Compared with Comparative Example 5 using single PA6 fiber without island structure, the release of active ingredients is blocked, and Comparative Example 3 does not add antimicrobial agents and only has the single action of quaternary ammonium salt. The island structure of Example 2 not only ensures the uniform dispersion of active ingredients, but also avoids their rapid loss, ensuring that they can reach an effective concentration for different microorganisms. At the same time, the addition of N-butylbenzenesulfonamide in the subsequent functional enhancement not only improves the mechanical strength of the material, but also adjusts the hydrophilicity and hydrophobicity of the fiber surface, making it easier for antimicrobial components to contact microorganisms and further expanding the antimicrobial coverage. This micro mechanism of molecular structure design-active ingredient synergy-carrier structure optimization, combined with the protection of active ingredient release efficiency in application scenarios, together gives Example 2 better antimicrobial broad-spectrum, enabling it to effectively inhibit the growth of different types of microorganisms such as bacteria and fungi, forming a larger inhibition zone.

[0116] From Table 1, it can be seen that the diameters of the inhibition zones of each strain in Comparative Example 8 are the smallest, and those in Comparative Examples 1-2 are reduced to a certain extent, those in Comparative Examples 3-4 are greatly and obviously reduced, those in Comparative Examples 5-6 are reduced to a small extent, and that in Comparative Example 7 is reduced to the smallest extent. The diameters of the inhibition zones of Comparative Examples 1-2 are reduced to a certain extent. Compared with other comparative examples, this reduction is at a medium level. From the perspective of the bacteriostatic agent formula, it can be seen that the content of the key bacteriostatic component in Comparative Examples 1-2 is lower than that in the better comparative examples, but higher than that in the comparative examples with poor bacteriostatic effect. For example, if the content of a certain effective bacteriostatic component in the high-efficiency bacteriostatic comparative example is X%, and the content in Comparative Examples 1-2 is X%-Y%, this leads to a decrease in the bacteriostatic ability, but not to a very low level, so that the diameters of the inhibition zones are reduced to a certain extent. From the analysis of the mechanism of the bacteriostatic agent, it can be seen that the bacteriostatic agents of Comparative Examples 1-2 can act on the strains, but the action mode is not efficient enough. For example, a normal high-efficiency bacteriostatic agent can quickly inhibit the key metabolic enzyme activity of the strains, while the bacteriostatic agent of Comparative Examples 1-2 inhibits the enzyme activity at a slower speed, so that the strains can still grow and reproduce to a certain extent within a certain period of time, thereby reducing the diameters of the inhibition zones. In addition, if the diffusion rate of the bacteriostatic agent of Comparative Examples 1-2 is slightly slower than that of other better comparative examples, the diffusion range of the bacteriostatic agent will be limited within the same culture time, and the diameters of the inhibition zones will be correspondingly reduced. The diameters of the inhibition zones of Comparative Examples 3-4 are greatly and obviously reduced, which indicates that the bacteriostatic effect of Comparative Examples 3-4 is significantly different from that of other comparative examples. From the perspective of key factors, firstly, the formula of the bacteriostatic agent may have been fundamentally changed. For example, a component with important bacteriostatic effect is removed, or a substance that antagonizes the effective bacteriostatic component is added. Taking a bacteriostatic agent containing metal ions as an example, if the metal ions with good bacteriostatic activity in Comparative Example 3-4 are replaced by other ions without the same bacteriostatic ability, or a chelating agent that can complex the metal ions to make them lose activity is added, the bacteriostatic effect of the bacteriostatic agent will be greatly weakened, and the diameters of the inhibition zones will be greatly reduced. From the variable effects in the experiment, changes in the culture conditions may also be an important reason. If the culture temperature, humidity or culture time of Comparative Examples 3-4 are different from those of other comparative examples, such as the culture temperature is too high or too low, which is beyond the suitable temperature range for the action of the bacteriostatic agent and the strains, the activity of the bacteriostatic agent and the growth characteristics of the strains will be affected, so that the bacteriostatic agent cannot normally function, the strains can grow rapidly, and finally the diameters of the inhibition zones are greatly reduced.

[0117] The inhibition zone diameter of Comparative Example 5-6 showed a slight decrease, and the change trend was relatively flat. Analyzing the reason, from the perspective of fine-tuning of the bacteriostatic agent, some minor adjustments may have been made in the ingredients and manufacturing process, but these adjustments had little effect on the overall bacteriostatic effect. For example, in terms of ingredients, only the content of some auxiliary ingredients was slightly changed, and these auxiliary ingredients mainly play a role in stabilizing the bacteriostatic agent or promoting its dispersion in the culture medium, and have little effect on the key bacteriostatic effect. In terms of manufacturing process, the stirring time or temperature may have changed slightly, but it is still within a reasonable range and has not caused significant damage to the microstructure and activity of the bacteriostatic agent, so the inhibition zone diameter only decreased slightly. That is, the bacteriostatic agent can inhibit the growth of the bacteria, but the bacteria also have certain adaptation and resistance, and under this interaction, the bacteriostatic effect of the bacteriostatic agent does not change dramatically, resulting in a small change in the inhibition zone diameter. In addition, errors during the experiment may have had some impact on this result, but since the overall trend is relatively stable, errors are not the dominant factor. Comparative Example 7 has the smallest decrease, which indicates that it is significantly different from the other comparative examples in terms of inhibition zone diameter change. From the perspective of unique factors, the bacteriostatic agent formula of this comparative example may have been carefully optimized. For example, the concentration of the effective bacteriostatic component reached a relatively ideal level, which can fully exert the bacteriostatic effect and will not cause other negative effects due to excessive concentration. At the same time, some synergists may have been added to the bacteriostatic agent, which can enhance the affinity between the effective bacteriostatic component and the bacteria, or promote the diffusion of the bacteriostatic agent in the culture medium, thereby improving the overall bacteriostatic effect and minimizing the decrease in the inhibition zone diameter. From the perspective of bacterial adaptability, the bacteriostatic agent of Comparative Example 7 may have a unique mode of action, making it difficult for bacteria to adapt to it. Compared with other comparative examples, the bacteriostatic agent does not simply inhibit a certain physiological process of the bacteria, but interferes with the growth and reproduction of the bacteria through multiple pathways, making it difficult for the bacteria to resist the effect of the bacteriostatic agent through simple physiological regulation, so the bacteriostatic agent can maintain good bacteriostatic effect throughout the experiment, and the inhibition zone diameter changes little. In addition, the operation of this comparative example during the experiment was more precise, reducing error factors that may affect the experimental results, and to some extent, ensuring the stability of its inhibition zone diameter.

[0118] Table 2: Test the antibacterial efficiency of the broad-spectrum high-efficiency antibacterial high polymer composite material prepared in Examples 1-3 and Comparative Examples 1-8

[0119]

[0120] As can be seen from Table 2, the bacteriostatic rate of Example 2 is the best and the most efficient, and the core lies in that the micro-antibacterial system constructed by it forms a multi-dimensional synergistic effect from molecular structure, component action to carrier characteristics. First, the molecular structure of the self-made antibacterial agent lays the foundation for efficient antibacterial, N1-phenyl-N3,N5-di(pyridin-3-yl)benzene-1,3,5-triformamide is generated by the reaction of 1,3,5-benzene tricarbonyl chloride and 3-aminopyridine, which has three amide bonds and multiple pyridine rings, and the lone pair electrons of the nitrogen atoms on the pyridine ring can form stable coordination bonds with silver ions. This coordination effect can achieve the controlled slow release of silver ions, avoiding the quick failure of silver ions due to the instantaneous release of a large amount of silver ions, and at the same time, the multiple active sites of the molecule can also enhance the adsorption capacity to the bacterial surface and improve the action efficiency. Then, the unique morphology of PA6 / PVA high molecular composite material plays a key carrier role, and its molecular structure provides a specific surface area far exceeding that of single PA6, creating sufficient sites for subsequent quaternary ammonium salt grafting and antibacterial agent loading. The cationic quaternary ammonium groups carried by the in-situ copolymerized methacryloyloxyethyl trimethyl ammonium chloride will strongly bind with the anionic groups such as phospholipids and proteins on the surface of the bacterial cell membrane through electrostatic attraction, rapidly destroying the integrity of the cell membrane, leading to the leakage of cell contents and the preliminary inactivation of bacteria, and at the same time, the increase in cell membrane permeability also opens the door for the entry of silver ions and nanosilver. The addition of nanosilver further strengthens the antibacterial effect, and its extremely small particle size greatly expands the contact area with bacteria, not only intensifying the structural damage on the cell membrane surface in cooperation with quaternary ammonium salt, but also penetrating into the interior of bacteria to combine with key biological molecules such as enzyme active centers and DNA, inhibiting enzyme reactions and hindering DNA replication, thereby cutting off the survival ability of bacteria from the core link of their life activities. In addition, the addition of N-butyl benzene sulfonamide improves the compatibility of the antibacterial agent, quaternary ammonium salt and the fiber matrix, avoiding the agglomeration of functional components and ensuring the uniform distribution of each active unit in the material; the 5-10 μm pore structure formed after the removal of residual PVA in the dissolving step not only ensures sufficient contact between the antibacterial components and bacteria, but also maintains the stability of the material structure and prevents the loss of functional components. Finally, the cell membrane damage effect of quaternary ammonium salt, the sustained antibacterial effect of silver ions, and the intracellular inhibition effect of nanosilver, combined with the high loading capacity of high molecular composite material and the uniform distribution of components, form a multi-mechanism synergistic micro-antibacterial system, which can act on different types of microorganisms such as Escherichia coli, Staphylococcus aureus and Candida albicans at the same time, block the survival and reproduction of bacteria from multiple aspects, and thus achieve a high 24h bacteriostatic rate of more than 99.9%.

[0121] As can be seen from Table 2, the core reason for the data of Comparative Example 1 to decrease is that the active site of the antibacterial agent molecule is greatly reduced, which replaces 1,3,5-benzene tricarboxylic acid chloride with benzoyl chloride, the former contains three acyl chloride groups, which can react with 3-aminopyridine to generate N1-phenyl-N3, N5-di(pyridine-3-yl)benzene-1,3,5-tricarboxamide with three pyridine rings, which can not only stably combine more silver ions through coordination, but also enhance the interaction with bacteria through multi-site adsorption; while benzoyl chloride contains only one acyl chloride group, the active site of the single pyridine ring product formed after the reaction is greatly reduced, which cannot effectively load silver ions and also cannot efficiently adsorb bacteria, resulting in a significant decrease in the bactericidal efficiency of the antibacterial agent itself, and further causing the 24h inhibition rate, such as Escherichia coli, to decrease from 19.5% to 12.3%, and the antibacterial intensity, such as Staphylococcus aureus, to decrease significantly from 99.8% to 91.8%.

[0122] Comparative Example 2 directly lacks the key silver ion sterilization link in the antibacterial system because the silver ion immersion step is omitted, the silver ion introduced by the antibacterial agent in Example 2 can destroy the integrity of the bacterial cell membrane and interfere with the intracellular enzyme activity through slow release, while the antibacterial agent of Comparative Example 2 only retains the organic molecular skeleton, which can only rely on the weak adsorption of the pyridine ring to exert a weak antibacterial effect, and lacks the synergistic sterilization of silver ions, so the antibacterial mechanism is single, and therefore all the antibacterial indicators are significantly down, such as the 24h inhibition rate of Candida albicans, which decreases from 17.8% to 8.5%, and the antibacterial intensity, which decreases from 99.7% to 85.3%.

[0123] Comparative Example 3 does not add the antibacterial agent prepared by S1, which directly cuts off the core action chain of silver ion sustained release + organic molecular adsorption in the antibacterial system, and the high-efficiency antibacterial of Example 2 relies on the synergy of the antibacterial agent, quaternary ammonium salt and nano-silver, the silver ion provided by the antibacterial agent can supplement the sterilization effect of nano-silver, and its organic skeleton can also enhance the combination of the components and bacteria; after lacking the antibacterial agent, it is difficult for quaternary ammonium salt and nano-silver to form a sustained and efficient sterilization network, the total amount of antibacterial components is insufficient and the synergistic effect disappears, resulting in the inhibition rate to decrease to the lowest level, such as the 24h inhibition rate of Escherichia coli, which is only 6.2%, and the antibacterial intensity, which is only 65.3%.

[0124] Comparative Example 4 lacks the quaternary ammonium salt grafting step, which loses the key pre-link of destroying the bacterial cell membrane, and the cationic group of quaternary ammonium salt in Example 2 can quickly combine with the anionic cell membrane of bacteria through electrostatic action, destroy the membrane structure and improve its permeability, to create conditions for silver ions and nano-silver to enter the intracellular; without quaternary ammonium salt, silver ions and nano-silver are difficult to efficiently penetrate the bacterial cell membrane, and can only play a limited role on the cell surface, and cannot destroy enzymes and DNA in the intracellular, resulting in a significant decrease in the sterilization efficiency, such as the 24h inhibition rate of Staphylococcus aureus, which decreases from 19.1% to 9.5%, and the antibacterial intensity, which decreases from 99.8% to 84.2%.

[0125] The comparative example 5 replaces the PA6 / PVA high polymer composite with PA6 fibers, which destroys the load and release carrier basis of the antibacterial components. This structure has a super large specific surface area, can efficiently graft quaternary ammonium salt, load bacteriostatic agent and nano-silver, and the subsequent PVA dissolution can form a pore size conducive to the contact of the antibacterial components with bacteria; while the PA6 fibers have a single dense structure, small specific surface area, and weak grafting and loading capacity, which leads to uneven distribution of antibacterial components, reduces the probability of contacting bacteria, and also causes obvious skin irritation due to poor compatibility, and the mechanical properties also decrease due to structural differences, such as the fabric breaking strength decreases from 482 N to 356 N, and the bacteriostatic rate decreases accordingly.

[0126] The comparative example 6 does not add nano-silver, which misses the intracellular deep sterilization link. In the example 2, the nano-silver can penetrate the bacterial cell membrane into the intracellular due to the small particle size advantage, destroy the enzyme activity center and hinder the DNA replication, and form a three-layer sterilization network with the membrane damage of quaternary ammonium salt and the surface effect of silver ions of the bacteriostatic agent; without nano-silver, although the bacteria are affected by the membrane damage and the surface silver ions, the key life activities in the intracellular are not blocked, and there is still a possibility of survival and reproduction, so the bacteriostatic rate decreases, such as the 24h bacteriostatic rate of E. coli decreases from 19.5% to 15.8%, but the decrease is relatively small because the quaternary ammonium salt and the bacteriostatic agent still play a role.

[0127] The comparative example 7 does not add N-butyl benzene sulfonamide, which leads to the deterioration of the dispersibility of the antibacterial components. This substance can improve the compatibility of the bacteriostatic agent, quaternary ammonium salt, nano-silver and PA6 matrix as a compatibilizer, and prevent the aggregation of functional components; without adding it, the antibacterial components are easy to aggregate to form large particles, which on the one hand reduces the active sites in contact with bacteria, and on the other hand the aggregated particles are easy to fall off from the fibers, leading to the loss of components, and the poor compatibility also weakens the mechanical strength of the fibers, such as the tensile strength decreases from 55.6 MPa to 44.5 MPa, which finally causes a small decrease in the bacteriostatic rate, such as the 24h bacteriostatic rate of Candida albicans decreases from 17.8% to 16.2%.

[0128] In summary, the examples use grafted functional groups, precise proportioning, and wide-spectrum high-efficiency antibacterial high polymer composite to significantly improve the wide-spectrum and high-efficiency of the material antibacterial property. The organic antibacterial pyridine ring and inorganic antibacterial material metal silver are combined into an antibacterial agent, and then a long-chain quaternary ammonium salt is grafted by in-situ polymerization, and further compounded with N-butyl benzene sulfonamide, which effectively solves the defects of traditional antibacterial materials such as few bacteriostatic types, slow onset time and short action time; achieves 24h antibacterial rate of Gram-positive bacteria ≥99%, thin film virus titer reduction of 4.2log 10The 1h antibacterial rate is 95.4%, the dynamic friction coefficient is 0.2-0.4, the tensile strength is greater than or equal to 53MPa, the hand feeling is not lost while the tensile strength and antibacterial property are ensured, and the material is suitable for medical dressings, artificial joints, environment and industry fields, has excellent application performance, all indexes are in the high-performance optimization range, and each proportioning proves that: eliminating any core component will cause a certain performance dimension to be significantly deteriorated, changing the material ratio of the core component will also cause the performance to have a large deviation, and the irreplaceability of the application scheme is verified.

[0129] The above examples only illustrate the principles and effects of the application, and are not used to limit the application. Any person skilled in the art can modify or change the above examples without departing from the spirit and scope of the application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the application should be covered by the claims of the application.

Claims

1. A broad-spectrum, highly efficient antibacterial polymeric composite material, characterized in that, Includes the following components by weight: Carrier resin: 40-50 parts of polypropylene; Antibacterial agents: 30-40 parts modified PA6; 5-8 parts thymol; 5-8 parts nano zinc powder; 6-7 parts N-butylbenzenesulfonamide; Dispersant: Ethylene bis-stearamide and polyethylene wax in a 1:1 ratio, 3-5 parts; Reinforcing agent: 10-20 parts of EPDM rubber; Lubricant: 1-2 parts calcium stearate; The preparation method of modified PA6 includes the following steps: Preparation of S1.N1-phenyl-N3,N5-bis(pyridin-3-yl)phenyl-1,3,5-tricarboxamide silver S101. Formation of amide bonds: 3-aminopyridine and triethylamine were dissolved in acetonitrile solution and placed in a round-bottom flask. 30 mL of dichloromethane solution containing 1,3,5-benzenetricarboxyl chloride was slowly added dropwise using a constant pressure funnel under an ice-water bath. After stirring for 2 h, the ice-water bath was removed, and the mixture was stirred at room temperature for 48 h. The solid was collected by filtration and washed with saturated NaHCO3, water, and glacial ethyl acetate. The solid was then dried under vacuum to obtain a yellow powder product, namely N1-phenyl-N3,N5-bis(pyridin-3-yl)phenyl-1,3,5-tricarboxamide. S102. Silver ion impregnation: The N1-phenyl-N3,N5-bis(pyridin-3-yl)phenyl-1,3,5-tricarboxamide obtained in S101 was added to anhydrous ethanol and heated to 77°C. After complete dissolution, silver trifluoroacetate was added to the solution, and the mixture was heated to reflux at 60°C for 24 hours. After the solution was completely cooled, it was centrifuged and filtered, washed three times with ultrapure water, and dried under vacuum to obtain N1-phenyl-N3,N5-bis(pyridin-3-yl)phenyl-1,3,5-tricarboxamide silver, which is a brown powder. S2. Grafting of long-chain quaternary ammonium salts PA6 / PVA composite polymer was impregnated with a completely soluble methacryloyloxyethyltrimethylammonium chloride impregnation bath at room temperature. The material was then removed from the impregnation bath and squeezed dry using a laboratory rolling mill to 80% liquid content. It was then dried in an oven at 80°C for 30 min, and finally cured at 120°C for 50 min. After the reaction, the product was placed in a desiccator and cooled to room temperature until constant weight was achieved. The dried sample was washed five times with hot water to remove polymethacryloyloxyethyltrimethylammonium chloride homopolymer. It was then placed in a 10% sodium nitrate solution and passed through a resin column at a flow rate of 1-2 BV / h until no precipitation occurred upon addition of silver nitrate to the effluent. The solution was concentrated under reduced pressure at 50-55°C, cooled to crystallize, and then dried in an oven at 30°C for 24 h to obtain quaternary ammonium salt-grafted PA6. Modification of S3.PA6 Measure trifluoroethanol into a container, weigh the quaternary ammonium salt-grafted PA6 obtained in S2 and add it to the trifluoroethanol solution. Place the suitable reaction vessel in a parallel synthesizer and heat and stir at 60°C for 2 hours. After the reactants are completely dissolved, add N1-phenyl-N3,N5-bis(pyridin-3-yl)phenyl-1,3,5-tricarboxamide silver obtained in S1 and stir at 60°C for 1 hour. Weigh out nano-silver and add it to the reaction system. Continue stirring at 60°C for 1 hour. After stirring is complete, sonicate for 0.5 hours to obtain modified PA6.

2. The method for preparing a broad-spectrum, high-efficiency antibacterial polymer composite material according to claim 1, characterized in that, The raw material molar ratio used in S101 is: 3-aminopyridine : 1,3,5-benzenetricarboxyl chloride = 3.0-3.1 : 1; the amount of triethylamine added is 10% of the total amount of the system.

3. The method for preparing a broad-spectrum, high-efficiency antibacterial polymer composite material according to claim 1, characterized in that, The mass fraction of the dichloromethane solution containing 1,3,5-benzenetricarboxyl chloride used in S101 is 70%; the yield of the reaction is approximately 40-50%.

4. The method for preparing a broad-spectrum, high-efficiency antibacterial polymer composite material according to claim 1, characterized in that, The raw material molar ratio used in S102 is: N1-phenyl-N3,N5-bis(pyridin-3-yl)phenyl-1,3,5-tricarboxamide obtained from S101 : silver trifluoroacetate = 1 : 3.0-3.

1.

5. The method for preparing a broad-spectrum, high-efficiency antibacterial polymer composite material according to claim 1, characterized in that, The methacryloyloxyethyltrimethylammonium chloride impregnation solution used in S2 is a 10% solution by mass and contains 2.0 g / L of potassium persulfate.

6. The method for preparing a broad-spectrum, high-efficiency antibacterial polymer composite material according to claim 1, characterized in that, The raw materials used in S2 are: 60-70 parts of PA6 / PVA polymer composite material and 50-60 parts of methacryloyloxyethyltrimethylammonium chloride impregnation solution.

7. The method for preparing a broad-spectrum, high-efficiency antibacterial polymer composite material according to claim 1, characterized in that, The raw materials used in S3 are: 50-60 parts of quaternary ammonium salt grafted PA6 obtained in S2, and 30-40 parts of N1-phenyl-N3,N5-bis(pyridin-3-yl)phenyl-1,3,5-tricarboxamide silver obtained in S1.

8. A method for preparing a broad-spectrum, highly efficient antibacterial polymer composite material, characterized in that, Includes the following steps: 1) Pretreatment: Dry the modified PA6 and polypropylene obtained from S3 in an oven at 80-100℃ for 4-6 hours, controlling the moisture content to ≤0.1% to prevent air bubbles from forming during extrusion; In a high-speed mixer, first add the dried modified PA6, dispersant, and antioxidant, and mix at low speed for 2 minutes; then add the premixed thymol, nano zinc powder, N-butylbenzenesulfonamide, and calcium stearate, and mix at high speed for 5-8 minutes until the material is uniform and free of obvious particles; 2) Initial plasticizing: Set the initial feeding speed to 30-50 rpm, matching the screw speed to ensure continuous material feeding; check that the pelletizer blade gap is 0.1-0.2 mm, and run it under no-load for 30 seconds to ensure that the blades rotate smoothly without abnormal noise; add water to the cooling water tank to a depth of 15-20 cm, and start the thermostat to adjust the water temperature to 20-30℃; start the twin-screw extruder, and gradually increase the screw speed from 100 rpm to 300-400 rpm to avoid instantaneous overload. After the screw runs smoothly, turn on the feeder and feed the premixed material modified PA6 + antibacterial agent + additives into the hopper at a uniform speed; 3) Melt forming: After the melt is extruded from the die, the strip is immediately pulled to the cooling water tank by a traction roller at a speed 5%-10% faster than the extrusion speed to ensure that the strip is straight and without bending; the cutter speed is 500-800 rpm, matched with the traction speed, to ensure that the particle length is 3-5 mm; after cutting, the qualified particles are immediately sent to a hot air circulating oven with a screen aperture of 2-6 mm and dried at 80-90℃ for 2-3 hours. The particles are turned over once every 1 hour to ensure uniform drying. The final moisture content is controlled at ≤0.05%. The dried masterbatch is packed into aluminum foil bags while hot, vacuum sealed, and the batch number, antibacterial agent type and dosage are marked on the outside of the bag.

9. A broad-spectrum, high-efficiency antibacterial polymeric composite material prepared according to claim 2 can be applied to medical dressings, artificial joints, home furnishings, personal care, and the bioenvironment.

Images